non idiopathic spine deformities in young children

Non-Idiopathic Spine Deformities in Young Children

MuharremYazici

Editor

Non-Idiopathic Spine Deformities in Young Children

ISBN 978-3-642-19416-0 e-ISBN 978-3-642-19417-7DOI 10.1007/978-3-642-19417-7SpringerHeidelbergDordrechtLondonNewYork

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EFORT2011Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting,reproductiononmicrofilmorinanyotherway,andstorageindatabanks.DuplicationofthispublicationorpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9,1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.ViolationsareliabletoprosecutionundertheGermanCopyrightLaw.Theuseofgeneraldescriptivenames, registerednames, trademarks,etc. in thispublicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotectivelawsandregulationsandthereforefreeforgeneraluse.Product liability:Thepublisherscannotguarantee theaccuracyofany informationaboutdosageandapplicationcontainedinthisbook.Ineveryindividualcasetheusermustchecksuchinformationbyconsultingtherelevantliterature.

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EditorMuharremYazici,MDDepartmentofOrthopedicsHacettepeUniversityFacultyofMedicineSihhiye,[email protected]

To my mentors,Marc A. Asher, Yucel Tumer, Adil Surat and A. Mumtaz AlpaslanFor teaching me that the process of learning is endless

vii

Preface

Thetermaxisdefinesastraightlineinterconnectingthetwopolesofasphericalobject.Inbiology,itdenotestheimaginarycentrallineofthebody,ormorespecificallythevertebralcolumn.Thebonesoftheskullandthevertebralcolumntogethermakeuptheportionoftheskeletalsystemthatisknownastheaxialskeleton.Thevertebralcolumndoesnotjustgeographicallyresideinthecenterofthebody;itoccupiessuchapositionphysiologicallyandfunctionallyaswell.Justasitisimpossibleforanobjectwithadeviatedaxistofulfillitspredetermined functionor structure,anydeviationof thevertebralcolumnfrom thenormalwillinvariablyaffecttheappearanceandfunctionofthewholebody.Ananomalysuchasthisappearingduringtheperiodofgrowthdoesnotjustexistinalimitedperiodoftimeandconstituteproblemswithastaticnature,butchangeswiththepassageoftimeandbecomesadynamicpathology.

Spinal disorders in small childrenhavebecomeoneof themost heatedly discussedsubjectsofspinalsurgeryinthepastfewyears.Impressiveprogressincorrectivedefor-mitysurgeryhaspavedthewayforproceduresusuallyreservedforadultsandadolescentstobemodifiedtobeusedforthetreatmentofspinaldeformitiesinmuchyoungerchildren.However, theabilityofperfectlycorrectingdeformities inall threeplanes inskeletallymaturepatientshasonlysolvedpartoftheproblem.Ithasalsogivenrisetoadditionalconcerns,especiallythoseregardingthelossofmotioninthevertebralcolumn.Minorormajorlossoffunctionintheshorttermandadjacentsegmentdiseaseinthelongtermareinevitable resultsof theseprocedures.Yet,when thecosmetic and functionalproblemscausedbythedeformityatthatmomentandthepotentialcomplicationsassociatedwithfusioninanundeterminabletimeinthefutureareweighed,usuallythelatterproblemispreferredasappliedinadvanceddeformitiesandcorrectivesurgery.Inyoungerchildren,however,amuchgraverproblemarisesthatdwarfsintheaforementionedonesinscope:thelossofthegrowthpotentialofthespinalcolumn.Theinabilityoftheaxial skeletontogrowdoesnotjustmeantheinabilityoftheaxistogrow.Itaffectsthegrowthpotentialofthe whole body. A spine not permitted to grow will result in a short trunk and anunderdevelopedthorax.Thecomplicationsthatfollowathoraxunabletodeveloparesohugeastonotevenbecomparedwiththosecausedbyavertebralcolumnthatisshort,immobileoracandidate foradjacentsegmentdegeneration.Thoracic insufficiency isalife-threatening,orintheveryleast,profoundlyquality-of-lifealteringcomplication.

The last decade of pediatric spinal surgery has been about trying to understand thecausesandresultsofearlyonsetscoliosis,identifycoexistingproblems,foreseeingnewonesandsolvingthemall. Isincerelyhopethat thisbookwillbeacontributionto this

viii Preface

struggle,howeversmallitmaybe.Theinformationcontainedinthisbookisderivedfromthevaluableexperiencesofthosespinalsurgeonsthatareinvolvedwiththemanagementofyoungchildrenwithspinaldeformitiesintheirday-to-daypractice,andwill,hopefully,assistthepracticeofeveryothersurgeoninterestedinthissubjectwhilestimulatingupandcomingresearchintothefield.

Animportantportionofthecontentofthisbookwascoveredduringthepre-meetingcourseofthe28thEPOSMeetingin2009inLisbon.Althoughtheydidnotparticipateasspeakersinthiscourseatthattime,CarolHasler,IlkkaHelenius,DrorOvadiaandThanosTsirikoshavekindlyagreedtosharetheirknowledgeandexperienceforthecreationofthisbook.Also,withoutthebeliefinandsupportofEFORTSecretaryGeneralandLisbonEPOSMeetinghostManuelCassianoNeves,thepublicationofthisbookwouldnotbepossible.WeareabletohaveabooksuchasthisbecauseEFORT,oneoftheleadingteach-ingorganizationsinorthopaedicsurgeryintheworld,believedinthesignificanceofthisundertakingandneverwithhelditsgeneroussupport.

Iamproudtohavebeenchosentoleadthisprojectandwould,oncemore,liketothankeverybodyinvolvedfortheircontributions.

Ankara,Turkey MuharremYazici

ix

Contents

Part I Growth

1 Normal and Abnormal Growth of Spine........................................................ 3IlkkaJ.Helenius

Part II Evaluation

2 Clinical Evaluation............................................................................................ 17DrorOvadia

3 Radiologic Evaluation of Non-Idiopathic Early Onset Spine Deformities......... 25JorgeMineiro

Part III Deformities

4 Congenital Deformities of the Spine................................................................ 45AthanasiosI.Tsirikos

5 Neuromuscular Spine Deformities.................................................................. 73Carol-ClaudiusHasler

6 Cerebral Palsy................................................................................................... 77FreemanMiller

7 Duchennes Muscular Dystrophy and Spinal Muscular Atrophy................ 87DietrichSchlenzka

8 Other Neuromuscular Disorders with Scoliosis............................................. 97Carol-ClaudiusHasler

Part IV Management

9 Delaying Tactics: Traction, Casting, and Bracing.......................................... 109CharlesE.JohnstonII

x Contents

10 Indications for Non-fusion Operative Techniques in Non-Idiopathic Scoliosis........................................................... 121CharlesE.JohnstonII

11 Growth Modulation Techniques for Non-Idiopathic Early Onset Scoliosis........................................................................................ 133EricJ.WallandDonitaI.Bylski-Austrow

12 Instrumentation in the Childhood Spinal Deformities: Challenges, Problems, Limitations, and Solutions......................................... 145MuharremYaziciandZ.DenizOlgun

13 Fusionless Instrumentation for Non-Idiopathic Spine Deformities of Young Children: The Growing Rod Technique......................................... 157MuharremYaziciandZ.DenizOlgun

14 VEPTR Instrumentation in Early Onset Scoliosis......................................... 167FritzHefti,ArneMehrkens,andCarol-ClaudiusHasler

Index........................................................................................................................... 173

Part I

Growth

3M. Yazici (ed.), Non-Idiopathic Spine Deformities in Young Children, DOI: 10.1007/978-3-642-19417-7_1, 2011 EFORT

1.1 Introduction

Height will increase by 350% and weight 20-fold from birth to adulthood (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006). The spine, femur, and tibia will triple in length. In addition to two-dimensional growth, also volumetric growth occurs: at birth the volume of thorax is 6.7% of the final volume and the volume of lumbar vertebrae will be multi-plied by six from the age of 5 years to skeletal maturity. The growth of spine, thoracic cage, and lungs are closely associated with each other (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006). Disturbance within spinal or thoracic cage growth will adversely affect growth of lungs. Disturbance of growth may be due to dietary conditions (lack of energy, vitamin D, calcium, etc), skeletal dysplasia, spinal deformity, spinal fusion at an early age, and localized factors (after skeletal infections, trauma, etc.). In this chapter, focus will be on normal growth of spine, but also some disturbances of growth will be reviewed.

1.2 Spinal Ossification and Remodeling During Growth

Most vertebrae have at least three growth zones, and therefore the end morphology will be the result of 100 growth plates (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006). The pattern of posterior arch growth is linked to the presence of neural stem and differs from vertebral body growth, which more or less resembles growth of long bones. Ossification of

I.J. HeleniusTurku Childrens Hospital, Turku University Central Hospital, Kiinamyllynkatu 4-8, Turku FIN-20521, Finland e-mail: [email protected]

1Normal and Abnormal Growth of SpineIlkka J. Helenius

4 I.J. Helenius

1the vertebral bodies starts at the third month of intrauterine life. Three primary ossification centers are present within each vertebra, except for C1, C2, and sacrum. Ossification first appears in the lower thoracic and upper lumbar spine and radiates from there to both cra-nial and caudal direction (Ganey and Ogden 2001). Within the cervical spine, the primary ossification centers of the vertebral bodies appear sequentially after the primary centers appear in the vertebral arches. Vertebral body ossification begins in the lower cervical spine (C6 and 7). Posterior osseous defects, in which the ossification centers of the neural arch fail to fuse, are quite common: incidence of spina bifida occulta is estimated to be as high as 20%. The role of posterior element deficits in the development of conditions like spondylolisthesis is controversial.

The atlas (C1) centrum has one primary center of ossification, and each of the two neu-ral arches has their own (Ganey and Ogden 2001). The two posterior centers are present prenatally, while the anterior center may not appear until several months postnatally, which is good to know when evaluating this area in newborn and infants. The axis (C2) develops five primary and two secondary centers of ossification. The centrum and neural arches form in the conventional manner, and the odontoid process forms two laterally situated centers, which fuse almost always in the perinatal period.

At birth, lumbar vertebrae are relatively smaller than cervical and thoracic vertebrae (Dimeglio and Bonnel 1990; Dimeglio 1992). During growth, lumbar vertebrae and discs increase in size about 2 mm per year, while in the thoracic spine, the average increase is only 1 mm per year. The discs account for approximately 35% of the height of the spinal segment at birth, while at maturity this proportion is 22% in the cervical spine, 18% in the thoracic spine, and 35% of the lumbar spine (Dimeglio and Bonnel 1990; Dimeglio 1992). The anterior and posterior portions of the vertebrae do not grow in a similar fashion: in the thoracic spine, the posterior components grow at a faster manner than the anterior part, which results in the development of thoracic kyphosis. The reverse occurs in the lumbar spine. The anatomic shape of the vertebral bodies change during growth: the facet joint orientation is more horizontal in early childhood, increasing the risk of fracture dislocation of the spine in younger patients (Puisto et al. 2010).

1.3 Height, Sitting Height, and Length of Spine

Skeleton has two rapid growth periods from birth to 5 years and during puberty (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006). At birth, the standing height of the neonate is about 30% of final height. The spine makes up to 60% of the sitting height, whereas the head represents 20% and pelvis the remaining 20%. At birth, the sitting height averages 34 cm, at 5 years 62 cm, while at maturity 88 cm for women and 92 cm for men (Dimeglio 1992). The length of spine will nearly triple between birth and adult-hood. At birth, the vertebral column (C1-Sacrum) is approximately 24 cm long. At maturity the average adult spine is approximately 70 cm long in men and 65 cm in women. The cervical spine length averages 12 cm, thoracic spine 28 cm, lumbar spine 18 cm, and sacrum 12 cm.

51 Normal and Abnormal Growth of Spine

1.4 Cervical Spine Growth

At birth, the cervical spine measures 3.7 cm, growing about 9 cm to reach the adult length of 1213 cm (Dimeglio 2006). The length of the cervical spine will double by the age of 6. The cervical spine represents 22% of the C1S1 segment and about 15% of the sitting height. The diameter of spinal canal typically decreases from C1 to C7. In the adult, the normal transverse diameter of C3 is 27 mm and the average sagittal diameter is 19 mm.

1.5 T1S1 Growth

The T1S1 segment measures about 19 cm at birth, 28 cm at the age of 5, and 45 cm at skeletal maturity (Fig. 1.1). This segment represents 49% of the sitting height and 64% of the length of spine. During the first 5 years of life, its rate of growth is >2 cm per year, 0.9 cm between the ages of 5 and 10 years, and 1.8 cm during puberty (Dimeglio 1992). Thoracic spine (T1T12) is about 11 cm long at birth, 18 cm at 5 years of age, and will

10 years

Adult

L5

T12L1

T1

Sacrum

L5

T12L1

T1

Sacrum

L5

T12L1

T1

Sacrum

L5

T12L1

T1

Sacrum

Newborn

5 years

Boys Girls

Boys Girls

Boys Girls

Males Females

11 cm

7.5 cm

11 cm

7.5 cm

18 cm

10.5 cm

18 cm

10.5 cm

22 cm

12.5 cm

22 cm

12.5 cm

28 cm

16 cm

26.5 cm

15.5 cm

Fig. 1.1 Growth of the T1L5 segment of spine (Dimeglio and Bonnel 1990; Dimeglio 1992)

6 I.J. Helenius

1

reach a length of 28 cm in boys and 26 cm in girls at maturity. The thoracic segment has a rapid growth period from birth to 5 years of age (7 cm), a slower phase from 5 to 10 (4 cm), and a rapid growth through puberty (7 cm). The thoracic spinal canal is narrower than cervical or lumbar, thus producing risk for spinal cord in the case of traumatic injury or a process occupying space at this level. At the end of 5 years, the spinal canal growth to 95% of its definitive size (Fig. 1.2). The average transverse and sagittal diameters at T7 is about 15 mm.

The L1L5 segment is about 7 cm at birth and will increase to about 16 cm in men and 15.5 cm in women (Dimeglio 1992). In a similar fashion to thoracic spine, the growth velocity varies with age, being 3 cm from 0 to 5 years, 2 cm from 5 to 10 years, and more rapid through puberty (gain about 3 cm from 10 to 18). At birth, the spinal cord ends at L3, and at maturity it ends between L1 and L2.

The sagittal curves develop under the influence of neurologic maturation (Dimeglio 1992). The cervical lordosis appears when the child can hold his head straight (3 months). Thoracic kyphosis appears when the child can keep his trunk upright (6 months), and lum-bar lordosis appears when he can stand, at the age of 1416 months.

1.6 Thoracic Cage Growth

Dimeglio has termed the growth of the thorax or thoracic growth the fourth dimension of growth of spine (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006). From birth to age of 5, thoracic volume increases fivefold (Dimeglio 1992) (Fig. 1.3). On the other hand, by the age of 5 years, almost 60% of the sitting height is achieved, while only about 30% of thoracic volume has been achieved (Fig. 1.4). At the end of growth, the thorax has an anteroposterior diameter of about 21 cm in boys and 17 cm in girls, representing a growth of 9 cm since birth. The transverse diameter is 28 cm in boys and 24 cm in girls at the end of growth, meaning an increase of 14 cm since birth. The thoracic volume makes up to 6% at birth, 30% at the age of 5 years, and 50% at 10 years (Fig. 1.3).

In experimental models, rib elongation experiments produced scoliosis by pushing spine toward normal side (Sevastik et al. 1990). Rib resection (shortening) will produce

Newborn 5 years 10 years 15 years

Fig. 1.2 Growth of spinal canal. At the age of 5 years, spinal canal has achieved 95% of its adult size (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006)


scoliosis toward resection side (Langenskild and Michelsson 1961). This resulting sco-liosis can be partly corrected by elongation of convex ribs. Thus, the integrity of thoracic cage seems to be needed for normal spinal growth based on experimental data.

Thoracotomy in early childhood may result in rib fusions and pleural scarring (Gilsanz et al. 1983). Sistonen et al. (2009) evaluated 100 patients operated for esophageal atresia

Newborn 5 years 10 years 15 years

6%

30%

50%

100%

Fig. 1.3 Volumetric growth of thoracic cage (Dimeglio and Bonnel 1990; Dimeglio 1992, 2006)

Weight

26%

31%

Thoracic volume T1-S1 height

69%

L5

T12L1

T1

Sacrum

Fig. 1.4 Comparison of weight, thoracic cage volume, and T1S1 length at the age of 5 years. Almost 70% of spinal height has been achieved, in contrast to 30% of thoracic volume at this age (Dimeglio 1992)

8 I.J. Helenius

1during neonatal period. Of these 18% had developed scoliosis and rib fusions when followed up to adulthood.

Congenital scoliosis associated with rib fusions may cause restrictive lung disease by producing segmental hypoplasia of the hemithorax (Campbell et al. 2003). An extreme form of spinal and thoracic cage growth disturbance is spondylothoracic dysplasia (Ramirez et al. 2007). Extreme extrinsic restrictive lung disease will develop as a result of posterior rib fusion and severe shortening of the thoracic spine due to block vertebrae. Ramirez et al. (2007) evaluated the natural history of 19 patients prospectively from neonatal care and nine retrospectively. Mortality in early neonatal period was high (42%, 8/19). In the remaining patients, the average thoracic spinal segment was 5.1 cm, representing 24% of normal values. The average height of the patients was 1.15 m representing the 1.15 percen-tile. The average anteroposterior diameter of the chest was significantly reduced and the vital capacity was 28% of the predicted values estimated using arm span.

1.7 Lung Growth

Growth of lung occurs by volume expansion and tissue hypertophy (Sponseller et al. 2007; Davies and Reid 1970; Thurlbeck 1982). From birth to maturity, the functional residual capacity increases from 80 to 3,000 mL, and the lung weight increases from 60 to 750 g. Up to 85% of alveoli develop after birth (Davies and Reid 1970). Alveoli are added by multi-plication after birth until the age of 8 years, although the most rapid phase occurs from birth until the age of 3 years (Davies and Reid 1970; Thurlbeck 1982). In later childhood, lung volumes increase mostly by an increase in the size of alveoli. In normal children, the ratio of residual volume per total lung capacity increases with age due to increased stiffness of chest wall that is greater than respiratory muscle strength increment that occurs with age.

Severe scoliosis in early childhood increases mortality in early adulthood (Pehrsson et al. 1992; Boffa et al. 1984). In an autopsy study, Davies and Reid (1971) were able to demonstrate hypoplasia of the lung with decreased number of alveoli in early onset scolio-sis resulting to death. Lung volumes and pulmonary arteries were smaller and the latter also decreased in number. In addition, alveoli were reduced more in number than expected, sug-gesting a compensatory increase in size of each alveolus. In a long-term follow-up study, Pehrsson et al. (1991) were able to show that scoliosis patients with vital capacity below 45% of predicted or scoliosis of 110 are at a significant risk for respiratory failure.

1.8 Growth of Fused Spine with or without Instrumentation

Experimental high thoracic spinal fusion in young rabbits produces hypoplasia of the entire upper thorax including ribs, sternum, and lung volume (Canavese et al. 2007). In addition, asymmetric high thoracic tether at Th1-3 produced larger scoliosis than mid-thoracic tether in growing rabbits (Carpintero et al. 1997).


The loss of growth after circumferential spinal growth can be estimated using the for-mula by Winter (1977): 0.07 number of fused vertebrae years of growth remaining. Using this formula it can be estimated that on a 5-year-old girl, circumferential spinal fusion from T7 to T12 results in 4.2 cm loss of spinal growth (0.07 6 vertebrae 10 years growth). Dimeglio (1992, 2006) has proposed a more detailed formula based on sitting height and bone age. Using similar case as above (assuming that skeletal age is in this set-ting similar to bone age), the loss of growth can be calculated as follows: The remaining sitting height is about 26 cm for a 5-year-old girl. The thoracic spine makes up to 30% of the sitting height. The remaining growth of the thoracic spine is therefore at the age of 5 years: 26 cm 30/100 = 7.8 cm. The deficit of growth/sitting height due to six vertebral arthrodesis is 6/12 7.8 cm = 3.9 cm.

Immature vertebral bodies continue to grow after solid posterior spinal fusion (Hallock et al. 1957), which was later named as the Crankshaft phenomenon by Dubousset et al. (1989). Crankshaft has been defined as a curve progression of >10 following posterior fusion. Bending of the posterior fusion mass is thought to occur because of growth potential in the vertebral bodies of the fused segment. In the differ-ential diagnosis, adding on (curve progression above or below operated area) and pseudoarthrosis should be excluded. The ability of an anterior and posterior fusion to stop the spinal growth and crankshaft phenomenon is an accepted principle (Shufflebarger and Clark 1991) but remains to be proven by prospective high-level follow-up study (Sponseller et al. 2007).

In patients with infantile or juvenile idiopathic scoliosis, studies support the hypothesis that curve progression after posterior spinal fusion is proportional to the number of unfused growth centers and number of years of growth remaining (Sponseller et al. 2007; Dubousset et al. 1989). Growth areas of the spine in congenital scoliosis patients have varied growth potential as many vertebrae are malformed with failures of formation and segmentation. Therefore, the risk of crankshaft has been expected to be lower in congenital scoliosis patients.

Hefti and McMaster (1983) followed 24 infantile and juvenile idiopathic scoliosis patients for a mean of 4.5 years. They were operated using the Harrington instrumenta-tion and posterior spinal fusion at the age of 10 years, ranging from 8.5 to 11 years. The length of spine remained almost the same with only 0.4 cm growth. The height of the vertebral bodies in the fusion area increased by 0.067 cm, while the intervertebral disc spaces narrowed initially thus accommodating this growth. At the end of follow-up, the vertebral bodies bulged laterally toward the convexity and pivoted on the posterior fusion, giving rise to loss of correction (9), increasing vertebral rotation and recurrence of the rib hump.

Winter and Moe (1982) evaluated 32 congenital scoliosis patients operated before the age of 5 using posterior spinal fusion with abundant bone graft material with a mean fol-low-up of 9.5 years. Nine patients were followed up to maturity. A bending of solid spinal fusion 10 occurred in 6 (19%) of all patients. Of the nine patients followed up to skeletal maturity, the sitting height was less than third percentile of normal population in six patients. One of these nine patients developed lordosis of the whole spine (kyphosis of 73). On the other hand, in patients with congenital kyphosis, posterior arthrodesis alone was highly effective and gave better correction of kyphosis than combined anteroposterior approach (16 vs. 4).

10 I.J. Helenius

1Winter et al. (1984) also evaluated outcomes of posterior spinal fusion in 290 congeni-

tal scoliosis patients aged 5 or more at the time of surgery. Roughly half of the patients were operated without and half with Harrington instrumentation. Bending of solid spinal fusion 10 occurred in 19% of these patients during follow-up.

High thoracic spinal fusions above sixth thoracic vertebrae resulted in short thoracic spine and worse pulmonary function tests than mid-thoracic spinal fusions (Karol et al. 2008). A critical length of thoracic spine needed for sufficient lung volume development appeared to be 18 cm.

Pedicle screws in young children cross the neurocentral synchondrosis. In experimental models, asymmetric neurocentral synchondrosis closure will result in short and small pedi-cle on the concavity of scoliosis (Zhang and Sucato 2008). Recently, Ruf et al. (2009) reviewed 30 children operated for congenital scoliosis caused by a fully segmented hemivertebra using posterolateral technique and bilateral pedicle screws at the age of 1 and 2 years. Follow-up time was more than 5 years in 14 children and more than 10 years in 5 children. None of these children showed evidence of neurologic compromise and MRI and CT scans showed no evidence of spinal stenosis. Despite transpedicular fixation, the vertebral bodies demonstrated growth in longitudinal as well as vertical direction. However, the posterior instrumentation acted like tether leading to less kyphosis or increasing lordo-sis (Ruf et al. 2009). Three cases with multisegmental instrumentation developed thoracic hypokyphosis with growth. After rod removal, the thoracic spine regained kyphosis.

1.9 Fusionless Instrumentation

Dual growing rod constructs represent the current golden standard surgical treatment option for progressive early onset scoliosis patients, in whom a long section of the spine is involved in the deformity or if fusion of a long section is required to achieve curve control (Yazici and Emans 2009). In a multicenter study, Akbarnia et al. (2005) evaluated 23 patients (7 idiopathic, 3 congenital, 13 secondary) with a minimum 2-year follow-up. All patients underwent lengthening of the implants every 6 months. The average number of lengthening was 6.6 and this resulted in growth of 4.6 cm or 1.2 cm/year. Patients with congenital scoliosis received significantly less length during initial procedure while length-ening produced similar growth. Distraction of the spine with growing rods may stimulate growth of spine, since growth of 1.2 cm per year exceeds that of normal spine. Recently, growing spine study group (Sankar et al. 2009) evaluated the received T1S1 gain over following surgical lengthening. A decrease of T1S1 gain from 10 mm at first lengthening to 6 mm at seventh lengthening occurred, but still some gain occurred even after multiple lengthening.

VEPTR implant has been designed primarily for the treatment of congenital scoliosis associated with fused ribs (Campbell et al. 2004a). Campbell et al. (2004b) evaluated the outcomes of 27 patients with congenital scoliosis associated with fused ribs, who under-went an opening wedge thoracostomy and VEPTR implantation at the age of 3.2 years with a mean 5.7-year follow-up. Twenty-five patients had at least one hemivertebra on the convexity and a unilateral bar on the concavity (mean length 4.2 vertebrae). The mean


length of thoracic spine was 11.7 cm preoperatively, 12.3 cm immediately after index procedure, and 15.7 cm at final follow-up, representing an increase of thoracic height a mean of 0.7 cm per year (range 0.21.37 cm per year). These findings of continued tho-racic spinal growth have been confirmed by Emans et al. (2005). On the other hand, rib-based instrumentation may increase the compliance of rib cage, thus decreasing functional lung volumes while increasing residual volume (Mayer and Redding 2009).

The most recent tool for correcting early onset scoliosis is the Shilla technique (Lenke and Dobbs 2007; McCarthy et al. 2008). It is a pedicle screw construct, with fixed apical pedicle screws and sliding pedicle screws on top and bottom of the construct with extra-long rods allowing growth along them. Recently, McCarthy (2008) has reported that trunk length has increased by 12% during 2-year follow-up in patients operated using the Shilla technique, but this growth includes also the immediate trunk lengthening due to scoliosis correction. Longer follow-up is needed to see whether local apical bony fusion or at the top or bottom fusion areas will diminish the remaining growth of spine. This kind of construct might be most suitable for syndromic early onset scoliosis patients, in whom repeated surgical procedures for lengthening purpose are a clear risk.

1.10 Conclusions

Spinal and thoracic cage growth is critical for lung growth and function as well as reason-able life. Spinal length will almost triple from birth to maturity. About 60% of the sitting height has been achieved by the age of 5 years, while only 30% of thoracic volume exists at this time (Fig. 1.4). The critical length of thoracic spine needed for satisfactory pulmo-nary function appears to be about 18 cm, which is the length of normal thoracic spine at the age of 5 years. The estimated loss of growth due to circumferential spinal fusion can be calculated by Dimeglios formula (Dimeglio 1992, 2006) including sitting height, skel-etal age, and number of fused vertebral bodies.

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Ganey, T.M., Ogden, J.A.: Development and maturation of the axial skeleton. In: Weinstein, S.L. (ed.) The Pediatric Spine. Principles and Practice, 2nd edn, pp. 354. Lippincott Williams & Wilkins, Philadelphia (2001)

Gilsanz, V., Boechat, I.M., Birnberg, F.A., et al.: Scoliosis after thoracotomy for esophageal atre-sia. AJR Am. J. Roentgenol. 141, 457460 (1983)

Hallock, H., Francis, K.C., Jones, J.B.: Spine fusion in young children: a long-term end-result study with particular reference to growth effects. J. Bone Joint Surg. Am. 39, 481491 (1957)

Hefti, F.L., McMaster, M.J.: The effect of the adolescent growth spurt on early posterior spinal fusion in infantile and juvenile idiopathic scoliosis. J. Bone Joint Surg. Br. 65-B, 247254 (1983)

Karol, L.A., Johnston, C., Mladenov, K.: Pulmonary function following early thoracic fusion in non-neuromuscular scoliosis. J. Bone Joint Surg. Am. 90-A, 12721281 (2008)

Langenskild, A., Michelsson, J.E.: Experimental progressive scoliosis in the rabbit. J. Bone Joint Surg. Br. 43-B, 116120 (1961)

Lenke, L.G., Dobbs, M.G.: Management of juvenile idiopathic scoliosis. J. Bone Joint Surg. Am. 89-A, 5563 (2007)

Mayer, O.H., Redding, G.: Early changes in pulmonary function after vertical expandable pros-thetic titanium rib insertion in children with thoracic insufficiency syndrome. J. Pediatr. Orthop. 29, 3538 (2009)

McCarthy, R.E., Cullogh, F.L., Luhmann, S.J., Lenke, L.G.: Shilla growth enhancing system for the treatment of scoliosis in children: greater than two year follow-up. Scoliosis research soci-ety 43rd annual meeting, Salt Lake (2008) p. 107

Pehrsson, K., Bake, B., Larsson, S., Nachemsson, A.: Lung function in adult idiopathic scoliosis: a 20 year follow up. Thorax 46, 474478 (1991)

Pehrsson, K., Larsson, S., Oden, A., Nachemsson, A.: Long-term follow-up of patients with untreated scoliosis. A study of mortality, causes of death, and symptoms. Spine 17, 10911096 (1992)

Puisto, V., Kriinen, S., Impinen, A., et al.: Incidence of spinal and spinal cord injuries and their surgical treatment in children and adolescents. A population based study. Spine 35, 104107 (2010)

Ramirez, N., Cornier, A.S., Campbell, R.M., Carlo, S., Arroyo, S., Romeu, J.: Natural history of thoracic insufficiency syndrome: a spondylothoracic dysplasia perspective. J. Bone Joint Surg. Am. 89, 26632675 (2007)


Ruf, M., Jensen, R., Letko, L., Harms, J.: Hemivertebra resection and osteotomies in congenital spine deformity. Spine 34, 17911799 (2009)

Sankar, W., Skaggs, D., Yacizi, M., et al.: Lengthening of dual growing rods: is there a law of diminishing returns? Paper #15 presented at 3rd international congress on early onset scoliosis and growing spine, Istanbul, Turkey, 2021 Nov 2009

Sevastik, J., Agadir, M., Sevastik, B.: Effect of rib elongation on the spine. Spine 15, 822829 (1990)

Shufflebarger, H.L., Clark, C.E.: Prevention of the crankshaft phenomenon. Spine 16(Suppl 8), S409S411 (1991)

Sistonen, S., Helenius, I., Peltonen, J., et al.: Natural history of spinal anomalies and scoliosis assosiated with esophageal atresia. Pediatrics 124, 11981204 (2009)

Sponseller, P.D., Yazici, M., Demetracopoulos, C., Emans, J.B.: Evidence basis for management of spine and chest wall deformities in children. Spine 32, S81S90 (2007)

Thurlbeck, W.M.: Postnatal human lung growth. Thorax 37, 564571 (1982)Winter, R.B.: Scoliosis and growth. Orthop. Rev. 6, 1720 (1977)Winter, R.B., Moe, J.H.: The results of spinal arthrodesis for congenital spinal deformity in patients

younger than five years old. J. Bone Joint Surg. Am. 64-A, 419432 (1982)Winter, R.B., Moe, J.H., Lonstein, J.E.: Posterior spinal arthrodesis for congenital scoliosis.

J. Bone Joint Surg. Am. 66-A, 11881197 (1984)Yazici, M., Emans, J.: Fusionless instrumentation system for congenital scoliosis. Expandable

spinal rods and vertical expandable prosthetic titanium rib in the management of congenital spine deformities in the growing child. Spine 34, 18001807 (2009)

Zhang, H., Sucato, D.J.: Unilateral pedicle screw epiphysiodesis of the neurocentral synchondro-sis. Production of idiopathic-like scoliosis in an immature animal model. J. Bone Joint Surg. Am. 90-A, 24602469 (2008)

Part II

Evaluation


2.1 Medical History

Evaluation of a child with scoliosis should begin with a comprehensive and complete his-tory followed by physical examination. The history should begin with prenatal information taken from the parents including health problems, previous pregnancies, medications taken during the pregnancy, and if any sonographic surveillance was performed, whether there were abnormal findings. Inquiries regarding length of gestation, type of delivery, childs presentation at birth, birth weight, and complications during birth, if any, should also be made (Akbarnia 2007). It is important to have information regarding other medical prob-lems especially of the genitourinary, cardiac, and nervous systems, and also of other mus-culoskeletal disorders such as DDH, club foot, and brachial plexus injuries (Winter 1983). General information regarding previous operations or illnesses may help to reveal disor-ders in other organ systems (McCarthy 2001).

It is important to ask about developmental milestones and the presence of cognitive delay, difficulties in learning, gait abnormalities, etc. (Wynne-Davies 1975).

2.2 Physical Examination

The purpose of the physical examination is both to access the spinal deformity, and to try and eliminate other associated disorders. At this young age group, the child should be examined fully undressed except for underpants. Examination starts with the inspection of

D. OvadiaDepartment of Pediatric Orthopaedic Surgery, Dana Childrens Hospital, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, 6 Weizman Street, 64239 Tel Aviv, Israel e-mail: [email protected]

2Clinical EvaluationDror Ovadia

18 D. Ovadia

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the global body balance, the childs posture and body habitus, symmetry of the limbs, arm spans, and chest or flank asymmetry as well as inspection of the skin for any pigment changes such as caf-au-lait spots, axillary or groin freckles as seen in neurofibromatosis (NF), hairy patches, hemangiomas or sinuses along the back midline indicating spinal dysraphism (Fig. 2.1).

The clinical plumb-line should be accessed in both coronal and sagittal planes by using a plumb bob. The bob is dropped from the C7 spinous process down and beyond the glu-teal crease (Fig. 2.2). In the normal spine it will fall within 12 cm of the midline. Global pelvic balance should be examined by palpating both iliac crests and if obliquity and leg-length discrepancy (LLD) are suspected, repeating the examination with small wooden blocks underneath the short extremity will allow elimination of the LLD contribution to the pelvic obliquity (Fig. 2.3a, b).

The next step should be the evaluation of the range of motion of the spine, the flexibility of the curve, and the amount of rotation as measured by the angle of trunk rotation (ATR) using the scoliometer while the child is positioned in the Adams forward-bending test (Fig. 2.4) (Bunnell 1984). The test should be performed twice, once when the examiner is standing directly behind the child, and a second time when looking down from the head toward the buttocks. This can be sometimes difficult in very young children with early

Fig. 2.1 Port-wine hemangioma is seen around the lower lumbar spine that is indicating an occult spinal dysraphism

192 Clinical Evaluation

onset scoliosis (EOS) and can be simulated by laying the child in a prone position over the examiners knee. Accessing curve flexibility can be evaluated in a similar way by placing the child in a lateral position.

Chest excursion should be examined by placing both hands over the childs chest from behind, and asking the child to take a deep breath (Fig. 2.5a, b). Limitation in chest excur-sion may indicate syndromic scoliosis or thoracic insufficiency syndrome (Campbell et al. 2003).

Next, the child is asked to walk in the room. First in a regular way followed by walking on tip toes and then, walking on heels. This will allow testing most of the muscle function of the lower limbs.

The child is then placed supine on an examination table. Limb range of motion is exam-ined to detect either contractures around any of the joints or generalized hyperlaxity (Fig. 2.6ac). Leg length should be accessed by measuring the distance between the ante-rior superior iliac spine and the medial malleolus of each leg, and then by repeated measur-ing of the distance between the umbilicus and the medial malleolus. Differences in both these measurements will detect true LLD, while by measuring of the different lengths between these types of evaluation; a component of pelvic obliquity should be suspected and further investigated.

Fig. 2.2 Shoulder height inequality, waist asymmetry, and loss of coronal balance are some of the physical features that can be observed during the physical examination of a child with early onset scoliosis

20 D. Ovadia

2 a

b

Fig. 2.3 Limb-length inequality may be a cause of scoliosis. (a) Scoliosis in this patient was caused due to an overgrowth of the right leg, which was treated with epiphysiodesis of the distal femoral and proximal tibial growth plates. (b) Upon correction of limb-length discrepancy, the scoliotic deformity has also markedly regressed with no other treatment


Fig. 2.4 A rib hump, thoracic in this figure, will become more prominent with the Adams forward-bending test, as explained in the test

a b

Fig. 2.5 Thumb excursion test: at rest (a) and inhale (b). During inhalation, while right thumb moves laterally away from the spine, left one stays at the same position because of chest hypokinesia secondary to rib fusion

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2Fig. 2.6 (a) Hyperlaxity may be associated with scoliosis and its diagnosis depends on several findings. Thumb hyperlaxity is demonstrated in this figure. The patients thumb can be painlessly brought to contact the dorsal aspect of the forearm. (b) Another finding of hyperlaxity is the ability to bring the fingers to a position that is parallel to the forearm. (c) Flexible pes planus may be another indicator of generalized hyperlaxity

Finally, the neurologic examination is completed by performing clonus and Babinski testing of the feet, tendon reflex testing on both upper and lower extremities, followed by abdominal reflexes. Absence of this latter reflex may be indicative of underlying neuro-logic problems (Zadeh et al. 1995).

After completing a full physical examination, a radiological evaluation of the child should be carried out (Dobbs 2001, Schwend 1995). The plain radiograph evaluation is discussed in a separate chapter.


2.3 Pulmonary Evaluation

The pulmonary system can be significantly affected by the structural changes brought about scoliosis and this is one of the reasons for increased morbidity and even mortality in chil-dren with EOS. This is due to both intrinsic (amount of alveoli) and extrinsic (thoracic volume) factors. Some of these children with severe deformities might even suffer from thoracic insufficiency syndrome (TIS), defined as the inability of the thorax to support nor-mal respiration & lung growth (Campbell and Smith 2007). The most common respiratory defect in scoliosis is restrictive, with a decrease in vital capacity (VC) and forced expiratory volume in 1 s (FEV1) in correlation with the severity of the deformity. Therefore, it is advis-able that all children with EOS should undergo pulmonary evaluation prior to any surgical treatment. Pulmonary function tests are the best means to perform preoperative assessment, yet some of these children are too young to collaborate and successfully perform these tests. In such cases a multispecialty evaluation should be performed separately by the pediatric orthopedist, pediatric pulmonologist, and pediatric anesthesiologist.

2.4 Cardiac Evaluation

In patients with congenital anomalies, preexisting morbidities, and those with severe sco-liosis curves, the cardiac system might be affected. There can either be primary additional congenital cardiac anomalies or secondary impairment related to the severity of the defor-mity possibly leading to cor pulmonale. In such cases it is advisable to refer the child to a pediatric cardiologist for examination and to perform investigations including ECG and echocardiogram.

References

Akbarnia, B.A.: Management themes in early onset scoliosis. J. Bone Joint Surg. Am. 89, 4254 (2007)

Bunnell, W.: An objective criterion for scoliosis screening. J. Bone Joint Surg. Am. 66, 13811387 (1984)

Campbell, R.M., Smith, M.D.: Thoracic insufficiency syndrome and exotic scoliosis. J. Bone Joint Surg. Am. 89, 108122 (2007)

Campbell, R.M., Smith, M.D., Mayes, T.C., et al.: The characteristics of thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis. J. Bone Joint Surg. Am. 85, 399408 (2003)

McCarthy, R.E.: Evaluation of the Patient with Deformity: The Pediatric Spine, 2nd edn. Lippincott Williams & Wilkins, Philadelphia (2001)

Winter, R.: Congenital Deformities of the Spine. Thieme-Stratton, New York (1983)

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2Wynne-Davies, R.: Infantile idiopathic scoliosis. Causative factors, particularly in the first six

months of life. J. Bone Joint Surg. Br. 57, 138141 (1975)Zadeh, H.G., Sakka, S.A., Powell, M.P., Mehta, M.H.: Absent superficial abdominal reflexes

in children with scoliosis. An early indicator of syringomyelia. J. Bone Joint Surg. Br. 77, 762767 (1995)


Very often the diagnosis of an early onset spinal deformity can be diagnosed at birth or very early on in life. The radiological assessment of an early onset spinal deformity will be based either on direct or indirect signs from the clinical observations no matter what the likely diagnosis is idiopathic or non-idiopathic. However, not all spinal deformities are obvious on clinical examination in very young children. In these cases the physician should be aware of the most common syndromes associated with spinal deformities in order to request the appropriate studies to rule out the presence of such a deformity.

In the infantile and juvenile age group with scoliosis several authors have pointed out the high incidence of neural axis abnormalities, despite low frequency of findings on phys-ical observation or clinical history (Lewonowski et al. 1992; Charry et al. 1994; Evans et al. 1996). Scoliosis may occasionally be the first sign of underlying neural axis abnor-mality in this age group (Gupta et al. 1998).

On a routine setup when we see a young child with a spinal deformity we will have to screen the patient carefully in order to be able to identify a cause for a deformity that is not common in this age group. On occasion, the diagnosis may be obvious either from the curvature itself (i.e., congenital scoliosis) or from the underlying condition known to be associated with scoliosis/kyphosis (i.e., VATER syndrome, Rett syndrome, Duchenne muscular dystrophy). Scoliosis is usually first detected during a standard physical exam-ination by a pediatrician, noticed by a childs parents, or during a full workup for the childs underlying condition (i.e., neuromuscular disease).

The workup of these childrens scoliosis should follow the same steps as for an idio-pathic case, but curve progression in these children is not only dependent on the matu-rity parameters. Many other factors, related to the underlying condition, play a relevant role in curve aggravation and contribute to a prognosis that is somehow unpredictable.

J. MineiroHospital CUF Descobertas, Rua Mario Botas-parque das Nacoes, 1998-018 Lisbon, Portugal e-mail: [email protected]

3Radiologic Evaluation of Non-Idiopathic Early Onset Spine DeformitiesJorge Mineiro

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3The choice of imaging modality is determined by age and clinical presentation of the

child as will be discussed.

3.1 Skeletal Maturity Markers

Skeletal maturity is an important issue in order to assess the remaining growth to establish the risk of progression of a spinal deformity. It has indeed several components as chrono-logical age, height and weight changes, and skeletal and sexual maturation. It would be ideal for the physician to have a maturity measurement that would be simple, readily avail-able, and that would correlate with scoliosis progression. The most rapid growth phase corresponds to the accelerating phase of the pubertal growth spurt which is characterized by a gradual increase in the spinal growth rate (Dimeglio 2001). However, we do need to have a more accurate idea on the skeletal bone age and growth remaining for the child that pres-ents in the clinic with spinal deformity this can be estimated by several techniques that will be subsequently described, with radiographs from different bones in the skeleton.

However, when we talk about curve progression in non-idiopathic scoliosis, we have to take into account not only the maturity parameters (and skeletal markers) but also many other issues that are related to the underlying condition (i.e., neuromuscular scoliosis). In these cases the natural history of curve progression in the sagittal plane is even less well defined and predictable than scoliosis. The rate of scoliotic curve progression does vary among the different conditions and although aggravation is common in both cerebral palsy (CP) and Duchenne muscular dystrophy, in some of the CP children curves may develop very early on (before 8 years) and may require treatment between 4 and 6 years of age. In children with severe spinal muscular atrophy, scoliosis may become fixed by 68 years of age and when we look at paralytic curves, most of them remain flexible and do not prog-ress beyond 90 until the adolescent growth spurt.

The behavior of curve progression in non-idiopathic scoliosis is difficult to predict as each case has its own particularities that are related to the underlying condition and also to the childs age. Physicians looking after these patients need to be aware of skeletal markers in order to help treating of these unfortunate children.

3.1.1 Risser Sign

Determination of skeletal age is an important issue for the planning of surgical/conserva-tive treatment as well as for establishing the prognosis of spinal deformities in young children. Skeletal age relies on the fact that bones grow and physes mature in an orderly sequence. The most used skeletal marker for patients with scoliosis is the iliac apophysis. However, many other regions of the skeleton can be used for the same purpose like the pelvis, the hand, the knee, and the elbow.

The Risser sign is based on the radiographic excursion of the iliac crest apophyseal ossification. It starts at the antero-superior iliac spine and progresses posteriorly to the

273 Radiologic Evaluation of Non-Idiopathic Early Onset Spine Deformities

postero-superior iliac spine. Risser sign has been modified to distinguish phases of matura-tion of the iliac apophysis by dividing the crest into four quarters on the antero-posterior radiograph of the pelvis. As the ossification progresses to grade IV, a cap covers the whole crest and in grade V the apophysis is completely fused to the iliac crest and is a sign of complete maturity.

However, during the last phase of growth the Risser sign remains grade 0 for a large period of time. Risser grade I only appears by 13.5 years of skeletal age in girls and 15.5 years in boys (Dimeglio 2001). The iliac apophysis does not begin to show ossification until on average 18 months after the curve acceleration phase, meaning that most curve progression has occurred well before Risser I grade is evident on radiographs (Sanders et al. 2007). Taken into account these facts, the iliac apophysis as skeletal marker does not help spine surgeons to distinguish maturity levels prior to Risser grade I.

Regarding imaging the Risser sign, Isumi (1995) pointed out the discrepancy of the radiographs used to assess the iliac apophyses postero-anterior or anteroposterior due to the radiographic parallax of the x-ray beam with the pelvic brim.

Although the Risser sign is a simple, easily available method for assessing skeletal maturity, it should be used cautiously when more accurate skeletal maturity determination is required (Fig. 3.1).

Fig. 3.1 Risser sign (difficult accurate assessment and large field radiation exposure)

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3.1.2 Triradiate Cartilage

The closure of the triradiate cartilage can split approximately the Risser grade 0 in two halves as it occurs around the skeletal age of 12 years in girls and 14 years in boys (Dimeglio 2001).

Triradiate cartilage closure (Fig. 3.2) has been used for the purpose of assessing the risk for crankshaft phenomenon after posterior spinal fusion in young patients with immature spines (Sanders et al. 1995; Shufflebarger and Clark 1991; Sanders et al. 1997; Roberto et al. 1997).

3.1.3 The Sauvegrain Method (Olecranon Method)

The Sauvegrain method for the assessment of skeletal age has been used in France for the past decades (Sauvegrain et al. 1962). It uses lateral radiographs of the elbow during the accelerating phase of pubertal growth spurt from the skeletal age of 1113 in girls and from

Fig. 3.2 (a c) Triradiate cartilage closure during Risser 0


13 to 15 in boys. Complete ossification of the elbow ossification centers coincides with the end of the accelerated growth velocity and marks the commencement of the decelerating growth phase (Dimeglio et al. 2005) (Fig. 3.3).

Dimeglio et al. (2005) have simplified the Sauvegrain method in order to allow skeletal age to be evaluated by simple assessment of this apophysis at regular intervals of 6 months. Skeletal age can be assessed by grading of the olecranon apophysis from the ages of 11 to 13 in girls and from 13 to 15 in boys at 6-month intervals. These five different phases start at 11 years of age with the two ossification centers that progress to form a rectangular ossification center in shape by the age of 12 in girls and goes on to fuse to the ulna shaft by the age of 13 in girls (15 in boys).

As in children with juvenile idiopathic scoliosis, the spinal deformity may develop prior to the pubertal growth spurt during Risser 0, which is the phase where 90% of the surgically treated curves do increase (Charles et al. 2006). During the long Risser 0 phase, the olecranon ossification center may help to identify immature patients with scoliosis who are at risk of developing crankshaft phenomenon (the two early phases with two ossifica-tion centers or a half moonshaped nucleus of the olecranon on the lateral radiograph) (Sanders et al. 1995; Sanders et al. 1997; Shufflebarger and Clark 1991; Roberto et al. 1997; Hefti and McMaster 1983; Dubousset et al. 1989).

3.1.4 Digital Skeletal Age (DSA)

Sanders et al. (2007) pointed out that although all four methods for determining skeletal maturation (the Tanner-Whitehouse-III RUS method, the Greulich and Pyle method, the Oxford method, and the Risser Sign) correlated significantly with the curve acceleration

3 Points

5 Points

6 Points

6.5 Points

7 Points

Triradiatecartilageclosure

Risser I

11

1311.5

13.512

14

12.5

14.5

1315

GirlsBoys

18 years18 years

Fig. 3.3 Sauvegrain method (Olecranon method) (Courtesy of A. Dimeglio)

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phase (CAP), the weakest of all was the Risser Sign. In all his patients, the CAP began during the Risser phase 0. From the individual bone components of the RUS method, the radius and ulna had the lowest correlation to the curve acceleration phase. They tested the RUS method without the radius and ulna, using the phalanx and termed the method Digital Skeletal Age (DSA). Radiographically, the timing of the curve acceleration phase corre-sponded to the change from a covered to a capped phalangeal epiphysis (Tanner-Whitehouse-III stage F to stage G) (Tanner 1959) (Fig. 3.4). In this method the carpal scores reached maturity at the time of the curve acceleration phase (Sanders et al. 2007).

Although the Sanders study was performed in girls, it is likely that the stage of skeletal maturity will also be a strong predictor of curve progression in boys (Sanders et al. 2007). Although a significant correlation between the Tanner-Whitehouse-III method and curve acceleration phase was shown, DSA score in particular appears to provide a more predic-tive maturity determination, identifying the period of maximum curve deterioration risk (Sanders et al. 2007).

f (covered) g (capped)Tanner-Whitehouse III Stages

Fig. 3.4 Tanner-Whitehouse III maturation stages proximal middle phalanx changes


3.2 Conventional Radiography

3.2.1 Plain Radiographs

The initial evaluation of a child with a suspected spinal deformity should consist of pos-tero-anterior and lateral radiograph of the entire spine, including the cervical spine and the pelvis. Measurement of a scoliosis curvature is by the Cobb technique (Cobb 1948), as has been the rule for past decades.

For those children that are not yet able to stand, the radiographs should be taken with the child lying supine, insuring that the upper cervical and lumbosacral areas are included in the images.

When children start walking, the spinal radiologic assessment should be preferably in the standing position, or taken sitting if they are not able to stand independently. Standing postero-anterior and lateral spine radiographs should be requested in order to document the curve size, to rule out congenital abnormalities, and to serve as a baseline for monitoring future progression. Lateral views of the spine standing should be done with the arms raised forward 45 as pointed out by Stagnara in order not to modify the lordosis or kyphosis (Stagnara et al. 1982) or with the fingertips on the clavicles as protocol in many centers (BrAIST).

In the past, con ed-down oblique views of the apex of the curve were routinely obtained to give a good antero-posterior view of the rotated vertebra and would help detecting hidden skeletal abnormalities. Today these views have been replaced by Computed Tomography (CT) reconstruction that gives the surgeon a two-dimensional reformatting or a three-dimensional reconstruction image that can be manipulated to give the treating physician more information about the deformity.

In most cases of early onset scoliosis, the chest dimensions and mechanics must be taken into consideration. With aggravation of the scoliosis, the thoracic asymmetry deteriorates, decreasing the height of the thoracic spine (defining the height of the thorax) and the height of the concave hemithorax will be more affected. Although aggravation of the scoliosis can be assessed on a plain radiograph by an increase in the Cobb angle and rotation of the verte-bral bodies in the curvature, it will not give the spatial dimension of the deformity and its effect on the thoracic function compromise. In these cases, it is important to assess the space available for the lungs; this estimate can be given by measuring the ratio (in percentage) of the height of the concave hemithorax compared with that of the convex hemithorax (Campbell et al. 2003). With modern imaging techniques the asymmetry between hemithoraces, as part of the thoracic deformity, can be assessed more accurately through CT. CT should therefore be considered part of the workup in the radiologic evaluation of these children with early onset spine deformities independent of its etiology as discussed later.

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33.2.2 Flexibility/Instability Testing

3.2.2.1 Bending/Traction Films

Once the decision has been made for the surgical management of scoliosis, the next step will be to determine which area of the spine needs to be incorporated into the fusion area. Although we realize that the vertebrae in the scoliotic curve need to be fused, should it be from end-to-end vertebra (Bute 1938), from neutral-to-neutral vertebra (Moe 1972; Golstein 1964) or should the fusion stop at the stable zone (Harrington 1972; King et al. 1983)? These criteria were developed prior to the introduction of modern segmental fixa-tion systems which can be used anteriorly or posteriorly. Despite controversy and different opinions, all criteria are based on the flexibility of the scoliotic curvature. This can be assessed either by bending or traction films. These films will provide not only information on the rigidity of the curves but also on the amount of correction that can be achieved safely and whether or not a secondary curve should be included in the initial fusion.

Side-bending films can be done either standing or supine. A bending film is usually done with maximal active side bending in the supine position and separate films should be obtained for each side (left and right bending) (Fig. 3.5). Occasionally, forceful bending may be used for special cases such as in neuromuscular scoliosis. The controversy on side-bending films being done standing or supine was answered by several studies in the early 1990s showing supine films to be better in demonstrating curve flexibility (Shufflebarger 1992; Transfeld et al. 1992).

Fig. 3.5 Supine side bending films


More recently, traction films have replaced the use of the side-bending films according to several authors. These can either be done on a Risser table, x-ray table (Fig. 3.6) or in certain cases on the operating table under general anesthetics for severely handicapped children that cannot cooperate with this maneuvre (i.e., patients with neuromuscular scoliosis or mental retardation) (Hamzaoglu et al. 2005). As was pointed out by Vaughan (1996), supine side-bending films proved to be more effective for selection of fusion levels than Risser table traction films in the case of scoliotic curvatures with a Cobb angle

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3 3.3 Spinal Deformity Measurement

3.3.1 Cobb Angle

Measurement of scoliosis curvature through the Cobb technique (1948) is used not only for the initial evaluation but also for monitoring of spinal curve progression in the future. According to the technique, the Cobb angle is measured between the endplates of the two end vertebrae (superior and inferior) on a single plane AP spine radiograph. As a single plane radiograph measurement it fails to account for vertebral rotation as it may not accu-rately demonstrate the severity of three-dimensional spinal deformity. The preselection of the end vertebrae using the same measuring tools for all radiographs may help reduce measurement error and therefore should be a rule to adopt whenever we have a case of early onset spinal deformity. At present, a great number of hospitals have digital radio-graphs that allow us a computerized measurement that may also help to reduce the mea-surement error induced by a pencil or marker.

However, it is the magnitude of the curvature measured by the Cobb angle that is the basis for decision making in the management of the spinal deformity. Despite the interob-server and intraobserver variability reported (from 2.6 to 8.8), it is undoubtedly an impor-tant method for the assessment of any of these early onset spinal conditions. Measurement variability in adolescent idiopathic scoliosis (Carman et al. 1990; Desmet et al. 1982; Morrissy et al. 1990; Ylikoski and Tallroth 1990) and congenital scoliosis (Facanha-Filho et al. 2001; Loder et al, 1995) have already been reported, but in children younger than 10 years of age with noncongenital scoliosis, Loder et al. (2004) pointed out that there must be a change of at least 7 to demonstrate significant progression.

Regarding the frequency of follow-up radiographs in these young children with spinal deformities there is no strict rule but it would be reasonable if the child has a rapidly pro-gressive curve, to repeat the radiographs in periods of 46 months. But if on the contrary, the curve is only minimally progressive, then repeat radiographs every 6 months or longer would be acceptable (Morrissy et al. 1990; Ylikoski and Tallroth 1990; Carman et al. 1990; Desmet et al. 1982). However, 4-month intervals are very short periods and radio-graphic changes are often not accurate enough for the physician to base his or her deci-sions. As far as radiation is concerned, we need to be aware that a 4-month interval would also mean that these children would have a greater number of radiographs and radiation exposure until the final procedure.

3.3.2 Spinal Penetration Index (SPI)

In 2003, Dubousset et al. (2003) reported on a deformity vertebral body protrusion that although part of three-dimensional scoliotic deformity could not be understood in terms of the more common Cobb angle measurement of scoliosis. This type of deformity has been


the cause of airway compression by vertebral bodies in the very severe thoracic scoliosis. Although apical lordosis of the thoracic spine is a constant finding in lordoscoliosis with the thoracic spine protruding into the chest cavity, the relevance of the antero-posterior diameter of the thorax relies on the indirect compromise of the vital capacity as has been stressed by Geyer (1998). Based on these findings, the SPI has been developed as a mor-phologic measurement that quantifies the penetration of the vertebral bodies and surround-ing structures in relation to the theoretical thoracic room calculated from a tangent to the right and left posterior ribs (Dubousset et al. 2003).

The SPI can be divided in two patterns Spinal Penetration Index Surface (SPIS) which is a two-dimensional measurement, and a Spinal Penetration Index Volume (SPIV) which is three-dimensional, both measuring the penetration of the spine and other accompanying structures inside the rib cage (Dubousset et al, 2003).

In a normal chest, SPIV can vary between 7% and 10% but in a severe lordoscoliosis it can increase to values of 18%, 26%, or more and in the case of SPIS it may reach 50% or even more. Both SPIS and SPIV should be used to compare the results between the pre- and postoperative period. Despite a good postoperative correction of the scoliosis curva-ture seen on the x-rays, when we think at the three-dimensional scale the results are very often not as obvious and the improvement in the SPIV is also less evident.

Dubousset et al. also defined the concept of two types of humps in thoracic scoliosis the visible, cosmetic rib hump and the hidden or functional vertebral hump (Dubousset et al. 2003). The visible or cosmetic rib hump which is the result of displacement of the rib and the spine due to the axial rotation of the scoliotic thoracic spine can be measured by tangential radiographs and surface three-dimensional topography. The technique for assessment of this deformity, determining the volume in excess on the convex side of the curve (exothoracic rib hump) (Fig. 3.7a) and the volume deficit on the concave side of the curve (exothoracic missing hump) (Fig. 3.7b), and the values would be determined by comparing it with the ideal normal transverse plane contour (Fig. 3.7). These findings can be used on clinical grounds helping out the surgeon on the decision to add any other pro-cedure for the hump management. For a common adolescent idiopathic scoliosis with a moderate exothoracic convex rib hump with a 1012 smooth slope on an inclinometer, no particular treatment is needed for the hump but only for the spine and this can either be

Fig. 3.7 Spinal penetration index (Courtesy of J. Dubousset)

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3through the front or back. Good correction of the spine rotation can improve the cosmesis generally by 50% or more. For the more severe thoracic scoliosis with an inclinometer of 1520 and a significant exothoracic concave missing hump, a classical convex thoraco-plasty in addition to posterior spinal instrumentation and fusion (either with or without an anterior release for prevention of the crankshaft phenomenon) should be done. In the most severe cases, with severe exothoracic rib humps, thoracoplasty on the concave side may be used to lift up the ribs and a rod can be placed in front of the ribs as was pointed out by Stagnara (1985).

For the cases with a significant endothoracic vertebral hump and compression of the airway, it is required to perform an osteotomy with anterior resection of part of the verte-bral bodies together with a posterior spinal instrumentation and fusion for decompression of the bronchi. In these patients hyperlordosis should be diagnosed early in order to pre-vent airway compromise and in the very young an anterior epiphysiodesis should be con-sidered (Dubousset et al. 2003) to prevent aggravation of the vertebral body protrusion.

3.4 Computed Tomography (CT)

For some complex early onset deformities, in particular congenital scoliosis (Fig. 3.8b), after removal of a spinal cord tumour (Fig 3.8a) or syndromic cases (Fig 3.8c and d), the CT provides a more detailed view of the deformity with an increased accuracy in defining the bony deformity as compared to the plain radiographs.

With the modern CT equipment, at the expense of an increased radiation exposure, it is possible to obtain three-dimensional reconstruction images. These films help a great deal to understand complex deformities and are also extremely helpful in establishing the surgi-cal strategy for the preoperative planning for correction of these curves. In the more com-plex type of congenital spinal malformation, these abnormalities had been classified as formation failures according to conventional classification (Winter 1983; Winter et al. 1968) based on plain radiographs, but three-dimensional analysis demonstrated many other conventionally unknown structures, suggesting a new malformation concept for this condition. This computerized analysis demonstrated posterior components of the mal-formed vertebrae which differed from the malformed anterior vertebrae and none of these abnormalities could be seen on the single plane radiology (Nakajima et al. 2007) (Fig. 3.8a). Advanced CT imaging (three-dimensional and curved/standard multiplanar reformatted images) allows a better understanding of some of these complex congenital spinal anoma-lies. In more than 50% of cases it has shown other components of these malformations that had not been identified before, either on plain radiology or on axial two-dimensional CT (Newton et al. 2002).

Another use of CT in the study of these early onset scoliosis is determining the extent of the chest wall deformities associated with these spinal deformities and in estimating the of preoperative lung volumes, particularly in the very young. In the case of posterior chest wall deformities, the use of the three-dimensional reconstruction helps to understand its relation to the spinal deformity.


Certain congenital scoliosis with severe spinal angulation and rotation may compro-mise thoracic function and growth as has been pointed out by Campbell (2003). However, the rotational component of the spinal deformity associated to another congenital abnor-mality of the chest wall, fused ribs, may induce severe distortion of the rib cage that requires a three-dimensional thoracic investigation. Three-dimensional loss of thoracic symmetry is difficult to assess on conventional radiographs and, therefore, can be mea-sured by CT. When evaluating these sick children in the clinic it may not be difficult to assess deterioration of the spinal deformity but it may be more troublesome to estimate the worsening thoracic asymmetry. Measuring deterioration of the thoracic rotation by the

Fig. 3.8 Spinal and Chest Computed Tomography (CT) in scoliosis of different aetiologies

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3increase in the angular relationship of the sternum to the sagittal plane of the spine may be one of the techniques to use in the clinic. Another method that has been described earlier (Dubousset et al. 2003) is the SPI assessing the reduced sagittal depth of the thorax and subsequent loss of thoracic volume and symmetry (Fig. 3.8c).

With advanced CT imaging studies such as three-dimensional reconstructions and transverse cut, images provide (Fig. 3.8a), an additional complement to the plain chest radiographs and give the treating surgeon the three-dimensional thoracic deformity.

3.5 Magnetic Resonance Imaging

The association between idiopathic scoliosis and craniovertebral abnormalities is well recognized. With the development of Magnetic Resonance Imaging (MRI), neural axis abnormalities, syringomyelia, and Chiari malformations are increasingly identified in children with scoliosis (even in idiopathic scoliosis). Although scoliosis can sometimes be the presenting sign in some of these conditions, very often the neurologic examination does not identify any abnormality (Park et al. 1997). Charry (1994) reported on 25 young patients with scoliosis with neural axis abnormalities but of these, 40% had very mild neurologic findings and the rest of them were asymptomatic.

On the other hand, the risk of neurologic complications in scoliosis surgery increases if these children are not screened appropriately (Nordeen et al. 1994). Although neuro-logically intact children with scoliosis may not need preoperative MRI, there are indeed certain patients at risk for which we should be aware. Children with juvenile-onset scoliosis (younger than 11 years at first visit), male gender, thoracic kyphosis >30, left-sided curves (thoracic or thoracolumbar), presence of pain, neurologic deficit including absent or asymmetrical abdominal reflexes, absent gag reflex (Inoue et al. 2004), rap-idly progressive curves, and severe curvatures in skeletally immature patients (Morcuende et al. 2003; Barnes et al. 1993) are a matter of concern and should be screened carefully and an MRI scan should be considered. According to Morcuende et al. (2003), the risk of neural axis abnormality increases if several of these features are presented together in the same patient. Dobbs et al. in a large multicentered study (Dobbs et al. 2002) have shown a 21.7% prevalence of neural axis abnormalities in otherwise asymptomatic children with infantile scoliosis and there was no correlation between the MR images, gender, curve magnitude, curve location or curve direction. When evaluating young children with spinal deformities, the orthopedic/pediatric sur-geon should be aware of the high risk of neural axis abnormalities that some of these patients have, in order to do the appropriate investigations needed before embarking on a more aggressive form of treatment for the scoliosis. It is a matter of concern the fact that >50% of children with idiopathic scoliosis and abnormalities on the MRI, will need a neurosurgical intervention between birth and the age of 10 years (Lewonowski et al. 1992; Charry et al. 1994; Gupta et al. 1998); therefore, within the same period of time progressive scoliosis may need surgical treatment, reinforcing the need for a proper screening of any atypical scoliosis.


MRI should also be an essential part of the evaluation in congenital spinal deformity and special attention should be paid to those cases with segmentation defects, mixed defects, and kyphosis (Basu et al. 2002) in order to rule out associated neural axis abnor-malities (Fig. 3.9).

For these patients with early onset spinal deformities and indication for an MRI scan, a T1- and T2-weighted sagittal screening images of the cervical, thoracic, and lumbosacral spine together with an additional sagittal and axial screening images of the craniocervical junction, cervicothoracic junction, thoracolumbar junction, lumbosacral junction, and the area of major deformity should be performed. Children with scoliosis and suspected spi-nal dysraphism should undergo routinely axial T1-weighted images through the conus and filum terminal in order to detect lipomas of the filum terminal (Fig. 3.9b and c), spi-nal cord tethering (Fig.3.9a), that could otherwise be missed on the saggital imaging (Saunders et al. 2007).

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Part III

Deformities


4.1 Introduction

Congenital deformities of the spine constitute a gradually blending spectrum of deformi-ties, ranging from a congenital scoliosis through kyphoscoliosis to a pure kyphosis. They are due to an asymmetrical failure of development of one or more vertebrae resulting in a localized imbalance in the longitudinal growth of the spine and an increasing spinal curva-ture affecting the coronal and/or the sagittal plane, which continues to progress until skel-etal maturity (McMaster and Ohtsuka 1982; McMaster and Singh 1999; Winter et al. 1968, 1973). The unbalanced development of the spine across the levels of the congenital verte-bral abnormalities can create a benign curve with slow or no progression during growth which may not require treatment other than observation. In contrast, certain types of con-genital anomalies affecting the vertebral column may produce a relentlessly aggressive deformity which can result in cosmetic, functional, respiratory, and neurological complica-tions and which necessitates early treatment. Und

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