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IMAGING OF LOW BACK PAIN I1 0033-8389/01 $15.00 + .OO
RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL
INSTABILITY AND DEGENERATIVE SPONDYLOLISTHESIS
Remy S. Nizard, MD, PhD, Marc Wybier, MD, and Jean-Denis Laredo, MD
Despite many efforts, there is no clear and widely accepted definition of lumbar instabil- ity because there are no unquestionable and currently applicable clinical or radiologic cri- teria available for this entity. Despite this problem of definition, an increasing number of lumbar spine fusions are performed for this specific diagnosis.15, 82 Conversely, degen- erative spondylolisthesis has an unequivocal radiologic definition. This article reviews the current concepts of lumbar instability and the different imaging modalities used to make the diagnosis as evident as possible. Degener- ative spondylolisthesis, which is a possible end stage of lumbar instability, is also dis- cussed. Particular attention is paid to the ra- diologic analysis of vertebral displacement, which is of pathophysiologic and therapeutic concern.
INTERVERTEBRAL INSTABILITY
Definition
In 1985, Kirkaldy-Willi~,4~ as the president of the International Society for the Study of
the Lumbar Spine, in an introductive lecture during a symposium on lumbar spine insta- bility raised three difficult questions: (1) what does the term lumbar instability mean, (2) how can it be detected, and (3) what are the best ways of treating varying degrees of this stage in the process of degeneration of the lumbar spine? Fourteen years later, and despite a large number of studies dealing with lumbar instability, including studies based on new imaging modalities, these questions remain unanswered. According to the American Academy of Orthopedic Surgeons: instability is defined as an abnormal response to applied loads, characterized by movement in the mo- tion segment beyond normal constraints. Pope and P a ~ ~ j a b i ~ ~ explained this response by damage to the restraints (including ligaments and muscles) that hold the spine in a stable position. Stokes and F r y m ~ y e r ~ ~ defined seg- menta2 instability as loss of spinal motion seg- mental stiffness, in such a way that force ap- plication to that motion segment produces greater displacement than is seen in a normal structure. This state leads to a painful condi-
From the Department of Orthopaedic Surgery (RSN), Service de Radiologie Osteo-Articulaire (MW, J-DL), H6pital Lariboisikre, Assistance Publique des HBpitaux de Paris, Paris, France
RADIOLOGIC CLINICS OF NORTH AMERICA
VOLUME 39 NUMBER 1 JANUARY 2001 55
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56 NIZARDetal
tion with the potential of progressive defor- mity and places neurologic structures at risk.
Biomechanical Background
During the movements of flexion-extension of the lumbar spine, rotation in the sagittal plane demonstrated by a change in the angle formed by the vertebral end plates at each intervertebral disk and translation in the sa- gittal plane (defined by a slip of one vertebra to the underlying one) may be observed. Ex- cessive displacements are restrained by nor- mal intervertebral structures. According to Panjabi,56 the load-displacement curve of the typical spinal motion segment is nonlinear with high flexibility when motion is around the neutral position of the spine and increas- ing passive resistance to motion nearer the end ranges of spinal motion. The total range of motion of a spinal motion segment may be divided into the neutral zone and the elastic zone. The neutral zone is that part of the range of physiologic intervertebral motion, measured from the neutral position, in which the spinal motion is produced with a minimal internal resistance and minimal expenditure of muscular energy.
As theorized by P~mjabi,5~ spinal stability depends on three functionally interdependent subsystems: (1) a passive subsystem, (2) an active subsystem, and (3) a neural control subsystem. These three subsystems adjust spine stability both around the neutral posi- tion and in extreme positions. The passive subsystem includes vertebral bodies, facet joints and their capsules, spinal ligaments, and passive tension from the musculotendi- nous units. Serial cuttings of these structures and finite element analysis helped to deter- mine their respective roles. In flexion, the main stabilizing structures are the posterior ligaments (interspinous and supraspinous lig- aments); the facet joints and their capsule; and the intervertebral disk.’, In extension, the main stabilizing structures are the anterior longitudinal ligament, the anterior part of the annulus fibrosus, and the facet joints.” Rota- tional movements are mainly controlled by the intervertebral disk and the facet joints.2O For side-bending movements, the intertrans-
verse ligaments probably play a significant role.% In the neutral zone of range of motion, muscles and tendons may act as transducers alerting changes in position and providing feedback to the neural control subsystem. In the end range of motion, these structures play a true mechanical role. The active subsystem consists of muscles and tendons. Differing roles have been assigned to unisegmental and plurisegmental muscle^.'^ Unisegmental mus- cles, such as intertransversarii and interspina- lis, located near the intervertebral center of rotation, may mainly act as transducers, send- ing information to the neural control subsys- tem for motion and position controls, whereas plurisegmental muscles (abdominal muscles and erector spinae) produce and control movements of the lumbar spine. The neural control subsystem includes the various trans- ducers mentioned previously and the neural control centers. The various transducers pro- vide information to the control centers, which determine the requirements to achieve stabil- ity. Several studies have suggested a relation- ship between low back pain and persistent deficits in neuromuscular control,s, 47, 48 but more data are needed to confirm this relation- ship. Based on these biomechanical data, Pan- jabi57 proposed to define clinical instability as ”a significant decrease in the capacity of the stabilizing system of the spine to maintain the intervertebral neutral zones within the physiologic limits, so that there is no neuro- logic dysfunction, no major deformity and no incapacitating pain.” Precise in vivo defini- tions of these physiologic limits remain to be determined.
Postoperative Instability
Instability is one of the modes of failure of lumbar surgery. It may occur in an operated intervertebral level after disk excision, exten- sive decompression, or at a level adjacent to a spinal fusion. Decompressive surgery is re- sponsible for muscular and ligamentous dam- age and bone removal that may impair stabil- ity at the operated levels. Preoperative risk factors of postoperative instability have been identified, and include the presence of an an- terior spondylolisthesis,38 L4-5 level as the
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 57
site of surgery,22* 71 a sagittal orientation of the facet j0ints,2~, 68 and radiographic signs of mild disk degeneration.68 Surgical removal of the whole facet joint also increases the risk of postoperative in~tability.~~ If it is defined as occurrence or progression of spondylolis- thesis, however, postoperative instability is not a frequent event.22* 26, 37* 38, 53
Spinal fusion has been shown to produce abnormal stresses on the adjacent cephalad or caudal nonfused segments. This is especially true with posterior fusion, which displaces the center of rotation of the lumbar spine in a cephalad and posterior direction.45, 46 Rigid fixation also is thought to produce additional stresses concentrated at the adjacent segments because of increased stiffness at the fused segments.45, 46 To evaluate the respective re- sponsibility of spinal fusion and the natural course of degenerative lesions in the occur- rence of degenerative changes at the adjacent operated levels, Hambly et a131 compared, at an average follow-up of 22.6 years, the plain radiographs of 42 patients who underwent posterolateral spinal fusion with those of an age- and gender-matched control group of patients simply evaluated for low-back pain. No statistical difference was observed be- tween the two groups in the frequency of radiographic degenerative changes at the transitional intervertebral levels (defined as the junction between fused and nonfused spine). The frequency of a dynamic instability (9% at the L2-3, 7% at the L3-4, and 13% at the L4-5 levels in the surgical group), defined as an anterior or posterior translation of more than 3 mm, was not statistically different be- tween the two groups. Moreover, the rates of dynamic instability at each intervertebral level observed by Hambly et a131 were similar to those found by Hayes et a132 on functional radiographs in asymptomatic male patients on pre-employment physical examination. The rates of postoperative spondylolisthesis (11% at the L 3 4 level after an L P S l fusion and 14% at the L4-5 level after a L5-Sl fu- sion31 in the surgical group) were not statisti- cally different between the two groups, but given the small number of patients in each group, the authors concluded that a degener- ative spondylolisthesis was more likely to de-
velop in fusion patients than in the general p~pula t ion .~~
Radiologic Evaluation
Because no well-established clinical criteria are available, the diagnosis of intervertebral instability is based on the radiologic finding of an abnormal vertebral motion. Differentia- tion between normal and abnormal motion, however, remains uncertain and challenging.
Neutral Roentgenograms
Several indirect radiographic signs have been reported to be indicative of or associated with spinal instability. Moderate disk degen- eration with mild space narrowing, osteo- sclerosis, and osteophytosis of vertebral end plates are thought to be associated with inter- vertebral instability; in contrast, a marked space narrowing is considered to be indica- tive of the late stabilization phase described by Kirkaldy-Willi~.~~? 85 According to Ma~rab,4~ the traction spur is a particular type of osteo- phyte that is located 2 or 3 mm from the end plate and has a horizontal orientation (Fig. 1). It is supposed to result from the tensile stresses exerted by the most external fibers of the annulus or those of the anterior longitudi- nal ligament on the vertebral body perios- teum in case of segmental instability.
The intervertebral vacuum phenomenon is defined by the presence of a gas collection
Figure 1. A T1 -weighted MR sagittal scan. Traction spur (arrowhead).
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58 NIZARD et a1
within the disk with two main radiologic ap- pearances. The typical central vacuum phe- nomenon is a gas collection that fills a large neocavity occupying both the nucleus and the annulus and is indicative of an advanced disk degeneration. Because instability may create excessive intervertebral distraction and nega- tive intradiskal pressure, allowing interstitial nitrogen to become gaseous, it is assumed that the intervertebral vacuum phenomenon is often associated with spinal instability. The other type of vacuum phenomenon is charac- terized by a gas collection located at the out- ermost part of the annulus fibrosus close to the vertebral corner. It is believed to be sec- ondary to a rupture of the insertion of Shar- pey's fibers and may also be the result of vertebral instability. Transitional vertebrae with a decreased motion at the L5-S1 level may induce overloading and instability at the L4-5 level. Unfortunately, the diagnostic value of these indirect signs of spinal instabil- ity remains unknown because their respective sensibility, specificity, and likelihood ratio cannot be determined in the absence of a well-defined gold standard.
Functional Radiography
Functional radiographs are the only im- aging technique that can demonstrate inter- vertebral instability or at least what is consid- ered to be an abnormal motion between two vertebrae (Fig. 2). This method is challenging and debatable, however, for three reasons.
First, reproducibility of functional radio- graphs is difficult and, according to Danielson et al,I4 a slight variation in patient positioning or in gantry tilting may result in a 10% to 15% variation in the range of vertebral dis- placement. These two factors (i.e., patient po- sitioning and direction of the X-ray beam) have to be accurate and reproducible to allow optimal measurement. Second, the way to perform functional radiographs and the method to measure displacements are still not ~tandardized.~~ Radiographic landmarks used for the measurements vary between reported studies and radiographic magnification is not always taken into account. In addition, the measured displacement is usually of the same magnitude as the precision error. Third, be- cause of the lack of gold standard to define intervertebral instability, the diagnostic value of functional radiographs cannot be deter- mined. These methodologic difficulties proba- bly account for the wide variation of the mea- surement results reported in studies conducted in asymptomatic subjects (Table
Vertebral instability is generally multidirec- tional,h3 whereas the displacement is evalu- ated in one plane at once. The sagittal and coronal planes are evaluated on plain radio- graphs and the axial plane by CT or MR imaging. In symptomatic patients, pain may act as a checkrein against bending of the trunk and so far results in underestimation of the true intervertebral motion. Functional radiographs performed with passive position- ing theoretically increase the range of the in-
1).7, 16, 32, 41, 61, 75
Figure 2. Functional lateral radiographs during a myelogram showing an L S L 4 intervertebral instability with a 16" angulation between flexion (A) and extension (6) and encroachment on the thecal sac.
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 59
Table 1. VALUES OF OBSERVED DISPLACEMENTS IN ASYMPTOMATIC SUBJECTS ON FUNCTIONAL RADIOGRAPHS
~~
Author Number Translation Rotation (Level)
Pearcy"' 11 - 13-16 (L1-L5)
Hayes et a13* 59 - 7-13 (Ll-W)
Boden and Wkd7 40 1.3 f 0.8 mm 7.7-8.2 (LI-W) 9.4 f 6.1 (L5-S1)
Dvorak et all6 41 2.63.1 l~un (Ll-W) 11.9-18.2 (Ll-L5) 17 f 4.3 (L5-Sl)
Tallroth et aIm 72 1470 2 5 nUn (L3-U) 13.3-16.4 (Ll-L5)
14 2 5 (E-S1)
14 (WS1)
-0.9 l~un k 1.5 (L5-Sl)
29% 2 5 mm (LA-L5) 7.1% 2 5 l~un (L5-S1)
17.3 f 5.1 (Women), 16.4 3.7 (Men) (E-Sl)
tervertebral motion because response to pain and upright position is attenuated.
In the coronal plane, a slight disruption of the alignment of the spinous processes and of the lateral border of the vertebral bodies with or without a lateral slip (laterolisthesis) should be checked carefully.
Sagittal displacements have been studied extensively. Functional radiography in the sa- gittal plane can be achieved either in maximal flexion and extension or with passive traction and compression. Measurements achieved on these radiographs are the translation of a ver- tebra with respect to the underlying one and the variation of the angle between the verte- bral end plates adjacent to the disk, which is commonly named rotation. Fribergu and Kalebo et al4I studied the sagittal displace- ments in the particular case of spondylolytic spondylolisthesis using the technique of trac- tion-compression radiography. To produce traction the patient is positioned to hang by hands from a horizontal bar perpendicular to the film plane with the toes slightly touching the ground; axial compression of the spine is brought about by positioning the patient to stand erect with an additional load of a knap- sack filled with 20 kg of sand. Recently, Pitka- nen et a P compared traction-compression with flexion-extension radiographs in a group of 306 patients with clinically suspected insta- bility based on (1) central low back pain on a prolonged static weight-bearing posture, (2) a visible and palpable step in the low lumbar spine, and (3) a so-called "instability catch." They found that flexion-extension demon- strated an abnormal motion in 23% of the patients, whereas traction-compression films
showed abnormal motion in only 2% of the patients. They concluded that traction-com- pression radiographs were of questionable value in the diagnosis of lumbar instability. Comparison of lateral views performed in the upright position with those obtained with ho- rizontal X-ray beam with the patient supine may also demonstrate an abnormal motion with spontaneous reduction of spondylolis- thesis when the patient is supine. This reduc- tion is sometimes seen on the lateral scout view performed during a CT examination or on MR images (Fig. 3). Finally, it can be con- cluded from this profuse literature that the value of functional radiographs remains de- batable. Many surgeons, however, use func- tional radiographs to disclose abnormal spi- nal motion before deciding on fusion. Unfortunately, even an abnormal motion is not necessarily related to the patient's clinical symptoms.
Computed Tomography Imaging
Computed tomography scan has a higher sensitivity than plain radiographs for the de- piction of a vacuum phenomenon within the intervertebral disk or the facet joints. As pre- viously suggested, however, the relationship between this finding and intervertebral insta- bility is questionable. Following Farfan et a1,I9, 2o Graf 24 described a technique of func- tional CT named twist-test that aimed to dem- onstrate a gap of the facet joint space during rotation of the trunk. The CT scan is taken through the facet joint while the patient twists the torso with the pelvis tightly strapped to
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60 NIZARD et a1
Figure 3. Intervertebral instability. A, Degenerative spondylolisthesis is visible on the lateral roentgenogram with the patient in the upright position. B, There is spontaneous reduction of the L 4 L 5 slippage on the sagittal T1-weighted MR image, with the patient supine.
Figure 4. Functional CT scan. Gap between the facet joints at the L4-L5 level during rotation. A, Neutral position with bilateral widening of the facet joint spaces. 8, Right rotation; no significant change. Left rotation, subluxation and joint space narrowing of the right facet joint.
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 61
the CT table. The gap appears as a vacuum phenomenon into the facet joint space during rotation. It is not known, however, whether this technique allows the differentiation be- tween normal and unstable spine and at what extent this finding is related to clinical symp- toms (Fig. 4).
Magnetic Resonance Imaging
Bram et a19 compared the MR imaging findings and those of flexion-extension radio- graphs in 60 patients (300 mobile lumbar units). They found no relationship between the occurrence of a sagittal translation of at least 3 mm on functional radiographs and the presence of abnormalities in the bone marrow adjacent to the end plates at MR imaging. Conversely, they found a significant associa- tion between radiographic instability and an- nular tears defined, according to April1 and Bogduk? as a high signal intensity dot on T2- weighted or postcontrast T1-weighted images and between instability and traction spurs. Unfortunately, lack of a good description of the population studied precludes a clear con- clusion on the relevance of these findings.
Lumbar Myelography
This is an invasive procedure that remains the only imaging modality allowing current evaluation of the compression of nerve roots and thecal sac in the upright position, and functional positions including end points of flexion, extension, and lateral bending of the lumbar spine. Dynamic myelography is the best method to determine which interverte- bra1 levels are responsible for the neurologic compression symptoms and the respective participation of the intervertebral disk and posterior elements in the production of the spinal stenosis. Myelography is still per- formed in some institutions as a preoperative procedure in case of neurologic impairment.
Other Diagnostic Methods
Several devices aiming at stabilizing the lumbar spine preoperatively have been tested
to predict the results of a lumbar fusion. The preoperative value of a lumbar cast is not established?, 66 A percutaneously settled ex- ternal fixation device theoretically allows a selective intervertebral segment immobiliza- tion. Several studies have tried to demon- strate the value of this procedure. The meth- odologic flaws of these studies prevent one from drawing a definitive conclusion on the relevance of this method?, 17, 36, n, ;rg Recently, Bednar and Raducan? in a prospective ran- domized study, showed that external fixation accurately predicted the result of a lumbar fusion. The aggressiveness of this procedure, however, and the high rate of complications including a rate of 9% of infection around the pins and a 9.8% rate of nerve root damage are dissuasive for an extensive and system- atic use.
Clinical and Radiologic Correlation
Clinical criteria of lumbar spine instability are still lacking." Low back pain has a very low specificity. The radiologic demonstration of disk degeneration is the only criterion sig- nificantly associated with low back pain as recently suggested by a meta-analysis."' Sev- eral clinical signs of lumbar instability have been identified by Paris.59 Complaints of "giv- ing away," a sudden catch, shake, or hitch during forward bending have not been rigor- ously evaluated.
As mentioned previously, Pitkanen et aP2 found that clinical signs of lumbar instability were poorly correlated with abnormalities found on functional radiographs. This dis- crepancy makes either the radiologic evalua- tion or the clinical definition of lumbar insta- bility questionable. Sat0 and KikuchP9 tried to evaluate the natural history of radiologic lumbar instability, excluding isthmic or de- generative spondylolisthesis. Fifty patients who had a radiographic diagnosis of lumbar instability were reexamined after 10 years. All patients suffered from incapacitating low back pain. Radiologic instability was defined as a 5-degree disk space widening or more by the Boxall et ale method or as a forward translation in flexion or posterior slippage in extension of at least 5% by the Taillard
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62 NIZARD et a1
meth0d.7~ Significant clinical symptoms were still present at the 10-year follow-up evalua- tion in 48% of the patients, whereas radiologic criteria of instability persisted in only 20% of patients. The association of a posterior disk space widening with an anterior slippage of the upper vertebra at the end point of flexion on initial radiographs was the only finding that was correlated with persisting and inca- pacitating low back pain. Unfortunately, the lack of clear definition of the inclusion criteria in this study limits the value of its conclu- sions.
Despite numerous efforts, determination of the relationship between clinical symptoms and radiographic abnormalities remains chal- lenging or even impossible because of the absence of a gold standard for the definition of lumbar instability.
Clinical Relevance
Many different surgical procedures have been proposed to achieve lumbar spine stabi- lization. The soft tissue stabilization system proposed by Graf," which is designed to pro- vide stabilization without fusion, has not been studied extensively and no convincing results have been reported.10, 25, 29, 51 Lumbar spine fusion remains the most widely used procedure to achieve stabilization. The suc- cess rates, as reported in a meta-analysis car- ried out in 1992, range from 16% to 95y0.~ Most of the studies reviewed in this meta- analysis, however, and those performed later, have major methodologic bias. Although lumbar fusion has been performed for more than 80 years, its clinical efficiency in lumbar spine degenerative diseases, especially in cases with no neurologic signs, remains to be established.
Yone et aim, 84 found in two studies that the results of decompression and fusion were better than those of decompression alone in patients who met preoperatively the radio- logic criteria of Posner et a P (Fig. 5). Results of these studies suggest that fusion is indi- cated when instability is radiologically dem- onstrated. Unfortunately, inclusion criteria and outcome measures were not defined clearly in these studies, and additional dem-
onstration is needed before accepting this conclusion as a rule.
DEGENERATIVE SPONDYLOLISTHESIS
Definition
Spondylolisthesis is easier to define than spinal instability. Etymologically, this term means "vertebral slipping." The so-called olis- thetic vertebra slips along the underlying ver- tebra. first differentiated the de- generative spondylolisthesis from the spondylolytic type; afterward he noticed on cadaveric specimens that the vertebral slip was not always associated with a neural arch discontinuity. Because this type of vertebral slipping mainly occurs in the elderly," New- man and Stone55 proposed the term degeneru- tive spondylolisthesis. It is caused by facet joint erosion and loosening of the muscular, capsu- lar, and ligamentous structures, which unite two adjacent vertebrae as the result of inter- vertebral degeneration.63 The incidence and prevalence of degenerative spondylolisthesis remain incompletely known.
Recently, Kauppila et al" studied the Fra- mingham cohort regarding degenerative spondylolisthesis. Among the 2824 subjects who had a first radiograph in 1967 to 1968, 1558 were dead by the follow-up examination and 617 accepted a follow-up radiograph in 1992 to 1993. The initial radiograph was done at a mean age of 54 years and the follow-up radiograph at a mean age of 79 years. At the follow-up examination, 12% of the men and 25% of the women had developed a degener- ative slippage of more than 3 mm. Mean inci- dence when both sexes were considered to- gether was 19.7%. The forward displacement was the more frequent type (68.3% of the slippage). The average anterior slippage was 18% k 5.5 and the average posterior slippage was 15% 4.0.
Vogt et alsl evaluated the prevalence of spondylolisthesis on the radiographs of 788 white women with a mean age of 71.5 years who were followed-up in a study on osteopo- rosis. The vertebral slip was measured at the L34, L4-5, and L5-Sl levels using a digitized
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 63
Anterior translation
>8%
L5 - s1 > 6%
L1- L2 to L4- L5
I I
= (RON)
Posterior translation Angdation
> 9 Yo > 9"
> 9 Yo > 1"
x X
100 ibd
0-
a
film measurement. The prevalence of an ante- rior slip of more than 3 mm was 28.4%, whereas the prevalence of a posterior slip of more than 3 mm was 14.2%. If a 5-mm cutoff point was used, the prevalence of anterior and posterior displacements was 14.2% and 3.2%, respectively. Seventy-three percent of the spondylolistheses were located at the L4-5 level, 28% at the L5-Sl level, and 12% at the L3-4 level. As expected, the prevalence of spondylolisthesis increased with age.
Facet joint degeneration probably plays a significant role in the genesis of degenerative spondylolisthesis,28 because in their normal arrangement facet joints prevent anterior slip- page.3O. 40, 70 A facet joint degeneration with
marked subchondral bone erosion is almost always present in degenerative spondylolis- thesis. Moreover, at the level of the spondylo- listhesis, facet joints usually have a relative sagittal orientation, which facilitates vertebral slipping and may be either a cause or a conse- quence of subchondral bone erosion.
The relationship between lumbar instability and degenerative spondylolisthesis was sug- gested by Kirkaldy-Willi~~~ who proposed a subdivision of lumbar spine degeneration into three phases. The first phase of joint dys- function is associated with slight reversible anatomic changes. In the second phase, insta- bility takes place. The intervertebral disk has a reduced height and loses its mechanical
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64 NIZARD et a1
properties. Ligaments and joint capsules be- come loose and degenerative changes occur in the facet joints. The result of these changes is an increased and abnormal range of move- ments. In the third and last stage, osteophytes and advanced disk space narrowing lead to restabilization of the intervertebral level with decrease or disappearance of the range of movement, sometimes after a vertebral slip- ping has occurred. Finally, if degenerative spondylolisthesis is the result of an interver- tebral instability that occurred at a given pe- riod in the natural course of the intervertebral degenerative process, the presence of a spon- dylolisthesis does not mean that vertebral in- stability is still present at the time of imaging because restabilization, as previously defined, may have already occurred.
Radiologic Evaluation
Direction of Slipping
The direction of slipping is defined ac- cording to the displacement of the upper (olisthetic) vertebra. Once degenerative changes have unlocked the intervertebral joint, the vertebral slipping occurs in a plane and along a direction that roughly depend on two factors: (1) the symmetry of facet joint lesions and (2) the distribution of weight- bearing forces at each intervertebral level. When facet joint degeneration and subluxa- tion are symmetric, vertebral slipping is mainly sagittal without significant rotatory
displacement. In the case of asymmetric sub- luxation, a rotatory displacement is associated with the anteroposterior displacement, the less dislocated joint being the axis of the rota- tion. In the latter situation, the orientation of the joint spaces is asymmetric with the most sagittally oriented joint space being the site of the most marked dislocation.
Anterior inclination of the disk space, which is usually present at the L 3 4 and the L4-5 levels, especially in cases of increased lumbar lordosis, induces anterior slipping, whereas a posterior inclination, which is usu- ally present at the L2-3 and L1-2 levels, may lead to posterior slipping (Fig. 6). In addition, a lateral slipping (laterolisthesis) may occur at one or two lumbar levels in elderly pa- tients. This lateral slipping is almost always associated with vertebral rotation and scolio- sis. This vertebral rotation may be induced by a pre-existing idiopathic scoliosis that in turn is worsened by the rotatory laterolisth- e s i~ . '~ If these patterns are the most frequent, however, anterior slipping may be observed at the upper vertebral levels, posterior slip- ping at the lower lumbar levels, and lateral slipping may occur without a pre-existing scoliosis and further result into de novo pro- gressive scoliosis." The anterior, posterior, and lateral degenerative spondylolistheses have a moderate magnitude of displacement. According to Kauppila et a1,4* average ante- rior slippage is 18% * 5.5% and average pos- terior slippage 15% & 4%. Only 10.6% of the 123 patients with vertebral slippage in this
Figure 6. An L4-L5 posterior slipping during extension. Flexion (A); extension (6).
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 65
study had a displacement exceeding 25% ac- cording to Meyerding scale.54
Consequences of Vertebral Slipping on the Lumbar Spinal Canal
Degenerative spondylolisthesis is fre- quently associated with a significant nar- rowing of the lumbar spinal canal and com- pression of the neural s t ruc ture~ .~~ Studies of the natural history of degenerative lumbar spondylolisthesis have suggested that pro- gression of the slippage occurs in 30% of pa- t i e n t ~ . ~ ~ Compression of the neural structures results from different mechanisms. In the case of symmetric anterior facet joint subluxation with anterior spondylolisthesis, the two lower facets of the upper (olisthetic) vertebra ven- trally impinge on the spinal canal and lateral recesses (Fig. 7). Osteophytes frequently in- crease the impinging effect of the subluxated facets. The narrowing of the spinal canal and the lateral recesses lead to a compression of the thecal sac in the central spinal canal or the nerve root in the lateral recess on both sides. On a lateral view, the central spinal canal narrowing is located between the neural arch of the upper vertebra and the posterior
Figure 7. Degenerative anterior spondylolisthesis with symmetric facet joint subluxation. Axial CT scan. The subluxated inferior apophyseal processes of the superior vertebra (arrows) almost completely narrow the central spinal canal.
and superior corner of the vertebral body of the underlying vertebra. In the case of sym- metric posterior facet joint subluxation, which results in a retrospondylolisthesis, a central spinal canal narrowing is less frequent be- cause the range of slipping of the upper verte- bra is lower. The backward displacement of the inferior facets of the upper vertebra re- sults in a widening of the facet joint spaces. On a lateral view, the central canal narrowing, when present, is located between the poste- rior and inferior corner of the upper vertebral body and the lamina of the underlying verte- bra (Fig. 8). In the case of asymmetric anterior subluxation of the facet joints, the inferior facet located on the side of the most im- portant dislocation impinges ventrally on the ipsilateral nerve root into the lateral recess.44 Narrowing of the central spinal canal is usu- ally milder than in the case of symmetric anterior subluxation. In addition, a foraminal disk herniation is frequently present at the same level and on the side of maximal sub- luxation and is attributable to the shear effect of the vertebral rotation on the intervertebral disk.44 This association of an asymmetric facet joint subluxation with a unilateral recess ste- nosis and an ipsilateral foraminal disk hernia- tion on the side of maximal facet joint sublux- ation is a characteristic triad of rotatory spondylolisthesis (Fig. 9).44
Additional Features
Nonspecific diffuse degenerative changes are usually present on plain radiographs at several lumbar intervertebral levels. The range of sagittal and coronal slipping at the level of spondylolisthesis can be evaluated on the lateral and anteroposterior radiographs. A significant rotatory displacement associated with the spondylolisthesis may result on the anteroposterior view in a subtle bayonet-like disruption in the alignment of the spinous processes at the level of the olisthetic verte- bra.
The participation of each anatomic degen- erative structure in the narrowing of the spi- nal canal can be evaluated on MR imaging and CT examinations. A facet joint synovial cyst in the lateral foramen or in the central
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66 NIZARD et a1
Figure 8. Myelogram with lateral functional views in extension (A) and flexion (6): L4-L5 degenerative retrolisthesis with compression of the thecal sac between the postero-inferior corner of L4 and the lamina of L5.
Figure 9. Characteristic triad of rotatory spondylolisthesis. Axial CT scans at the L4-L5 level. A, Asymmetric subluxation of the L4-L5 facet joints maximal on the right side (arrow) narrowing the right lateral recess. 6, lpsilateral foramina1 L4-L5 disk herniation (open arrow) impinging on the right L4 nerve root.
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Tabl
e 2.
CH
AR
AC
TER
ISTI
CS
OF
CO
MPA
RAT
IVE
STU
DIE
S O
N L
UM
BA
R F
US
ION
FO
R D
EG
EN
ER
ATI
VE
SP
ON
DY
LOLI
STH
ES
IS A
ND
LU
MB
AR
INS
TAB
ILIT
Y
Num
ber
of
Ref
eren
ce
Pat
ient
Con
ditio
n P
atie
nts
Trea
tmen
t 1
Trea
tmen
t 2
Trea
tmen
t 3
Allo
catio
n of
Tre
atm
ent
Her
kow
itz a
nd K
urP
Sp
inal
ste
nosi
s ass
ocia
ted
with
deg
ener
ativ
e sp
ondy
lolis
thes
is
with
deg
ener
ativ
e sp
ondy
lolis
thes
is
Lum
bar
sten
osis
with
out
radi
olog
ic in
stab
ility
Brid
wel
l et a
llz
Spin
al st
enos
is as
soci
ated
Gro
b et
aIz
6
Yon
e et
alw
L
umba
r st
enos
is w
ith
radi
olog
ic in
stab
ility
Feff
er e
t aIz
1 D
egen
erat
ive
Yon
e an
d Sa
kous
3 sp
ondy
lolis
thes
is
Lum
bar s
teno
sis w
ith
radi
olog
ic in
stab
ility
(P
osne
r cri
teri
a)
50
Dec
ompr
essi
on
Dec
ompr
essi
on a
nd
noni
nstr
umen
ted
post
erol
ater
al fu
sion
44
Dec
ompr
essi
on
Dec
ompr
essi
on a
nd
Dec
ompr
essi
on a
nd
noni
nstn
unen
ted
inst
rum
ente
d po
ster
olat
eral
fusi
on
post
erol
ater
al fu
sion
inst
rum
ente
d po
ster
olat
eral
ex
tens
ive
inst
rum
ente
d fu
sion
po
ster
olat
eral
fusi
on
inst
rum
ente
d po
ster
olat
eral
fu
sion
(10
)
post
erol
ater
al fu
sion
inst
rum
ente
d po
ster
olat
eral
fu
sion
(19
)
45
Dec
ompr
essi
on
Dec
ompr
essi
on a
nd li
mite
d D
ecom
pres
sion
and
17
Dec
ompr
essi
on (7
) D
ecom
pres
sion
and
19
Dec
ompr
essi
on (1
1)
Dec
ompr
essi
on a
nd
33
Dec
ompr
essi
on (14)
Dec
ompr
essi
on a
nd
Alte
rnat
ely
assi
gned
to
trea
tmen
t
Ran
dom
izat
ion
met
hod
not
stat
ed
Ass
igne
d w
ith th
e da
te of
ad
mis
sion
to
hosp
ital
Unc
lear
Unc
lear
Patie
nts’
cho
ice
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Tabl
e 3.
RE
SU
LTS
OF
CO
MP
AR
ATI
VE
STU
DIE
S O
N L
UM
BA
R F
US
ION
FO
R D
EG
EN
ER
ATI
VE
SP
ON
DY
LOLI
STH
ES
IS A
ND
LU
MB
AR
INS
TAB
ILIT
Y
FOIIO
W-U
P
Ref
eren
ce
(yea
rs)
Mai
n O
utco
me
Her
kow
itz a
nd K
~r
z~
3
(2.4
-4)
Eval
uatio
n ba
sed
on p
ain,
Brid
wel
l et all2
3.2
(2-7
) Sl
ip p
rogr
essi
on
activ
ity, a
nd p
aink
iller
use
Gro
b et
aIz
6 2.
5 (2
-3)
Eval
uatio
n ba
sed
on p
ain,
ac
tivity
, and
pai
nkill
er u
se
Yon
e et
alw
3
(2-5
) Ja
pane
se O
rtho
paed
ic
Feff
er e
t alz
l 4 (1-6)
Not
wel
l def
ined
A
ssoc
iatio
n sc
ore
Yon
e an
d Sa
kou"
2
min
imum
Ja
pane
se O
rtho
paed
ic
Ass
ocia
tion
scor
e
Sec
onda
ry
Res
ult
Out
com
es
T2 >
T1
(P=O
.OO
Ol)
Slip
pro
gres
sion
N
onfu
sion
T1
: 4/9
N
onfu
sion
T2
: 7/1
0 T
3 1
/24
(P =
0.00
1)
Wal
king
abi
lity
No
diff
eren
ce
T2>T
18O
Yo
good
and
ex
celle
nt v
s 28
% (P
c0.0
5)
Fusi
on: g
ood
(5),
fair
(3)
Dec
ompr
essi
on: g
ood
(5),
fair
(3),
poor
(3)
T
2>T
1 80
% go
od a
nd
exce
llent
vs
43%
Blo
od l
oss
Ope
rativ
e tim
e N
onfu
sion
D
evic
e-re
late
d co
mpl
icat
ions
Su
bjec
tive r
esul
t N
onfu
sion
In
stab
ility
Low
bac
k pa
in
Wal
king
abi
lity
Non
fusi
on
Res
ults
T1: 9
6%, T
2 28
%
36%
T2: 3
/10,
T3:
21/
24
28/3
1 be
tter i
f no
slip
T1 <
TZ
<T3
Tl<
T2<
T3
1 in
T3
4 de
vice
rem
oval
s
(P =
0.00
2)
prog
ress
ion
T2>
T1
(P<0
.05)
10%
Dec
ompr
essi
on (4
)
Sign
ifica
ntly
bet
ter i
n T2
Si
gnifi
cant
ly b
ette
r in T2
1/19
Com
plic
atio
ns
T2
nonf
usio
n T3
: inf
ectio
n, 1
scre
w o
ut
the
pedi
cle,
1 in
stab
ility
ab
ove
the
fusi
on
T2
1 fr
actu
re a
bove
, 1 ho
ok d
islo
catio
n -
T =
tre
atm
ent.
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RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 69
spinal canal is sometimes associated with the degenerative spondylolisthesis.@', 67 The range of rotation between two adjacent vertebrae may be measured with CT, but is mostly of theoretical interest. When spine fusion is con- sidered, T2-weighted M R images help in the evaluation of disk degeneration.
In our practice, lumbar myelography in- cluding functional views is still performed as a preoperative evaluation of the spinal steno- sis with neurologic symptoms. This technique may disclose a vertebral instability associated with the degenerative spondylolisthesis, which may explain to some extent why some cases with an apparently moderate spinal ca- nal narrowing on CT or MR imaging are symptomatic.
Clinical and Radiologic Correlation
The relationship between low back pain and degenerative spondylolisthesis is unclear. According to Vogt et a1,8l 37.5% of patients presenting with anterior spondylolisthesis had low back pain within the past 12-month period, whereas 32% of women without spon- dylolisthesis reported symptoms of low back pain. In addition, these authors found no sig- nificant correlation between anterior spondy- lolisthesis and the Occurrence of severe or incapacitating pain. Conversely, Kauppila et a14* in the Framingham cohort study showed that at the time of the second evaluation (at an average of 25 years after the first evalua- tisn) the rate of patients who experienced pain, aching, or stiffness in their back on most days was significantly greater in the spondy- lolisthesis group than in controls. In the case of degenerative spondylolisthesis with nerve root compression, the anatomic type of verte- bral slippage has, to some extent, an influence on the pattern of the neurologic symptoms, especially their unilateral or bilateral distribu- tion. In the case of symmetric (anterior or posterior) spondylolisthesis, with no or only mild rotatory component, nerve root involve- ment that is typically bilateral and pluriradi- cular is related to the compression of the the- cal sac in the central spinal canal and to a bilateral lateral recess stenosis. Conversely, in the case of asymmetric spondylolisthesis,
with a marked rotatory displacement, nerve root involvement is frequently unilateral in- volving one or two nerve roots on the side of maximal facet joint subluxation because of the compression of the nerve roots in the ipsilateral lateral recess and foramen. In a meta-analysis dealing with surgically treated degenerative spondylolisthesis, radiculopa- thy and neurogenic claudication were found preoperatively in 32% and 3% of the patients, re~pectively.~~
Clinical Relevance
Surgical treatment is indicated in degenera- tive spondylolisthesis associated with neuro- logic symptoms and when medical treatment has failed. Decompression with or without fusion may be discussed. In a meta-analysis of 25 studies dealing with the treatment of degenerative spondylolisthesis, Mardjetko et a150 suggested that patients who had spinal fusion associated with decompression had a better outcome than those treated with de- compression alone. Moreover, the fusion rate increased when fixation devices with pedicu- lar screws were used. It must be noted, how- ever, that only three of these studies were prospective and quasirandomized with im- perfect methods of treatment allocation (Table 2). In addition, these studies have several other serious weaknesses including lack of blinding and independent assessment of the outcome, which gave additional potential for bias. Despite these limitations, there is weak evidence that adding spinal fusion to decom- pression in degenerative spondylolisthesis produces less progressive slipping and better clinical outcome than decompression alone (Table 3).
References
1. Abumi K, Panjabi M, Kramer K, et ak Biomechanical evaluation of lumbar spinal stability after graded facetectomies. Spine 151142,1990
2. American Academy of Orthopaedic Surgeons: A Glossary on Spinal Terminology. Chicago, 1985
3. April1 C, Bogduk N High-intensity zone: A diagnos- tic sign of painful lumbar disc on magnetic resonance imaging. Br J Radio1 6361 , 1992
4. Axelsson P, Johnsson R, Stromqvist B, et al: External
![Page 16: Radiologic Assessment of Lumbar Intervertebral Instability and Degenerative Spondylolisthesis](https://reader035.vdocuments.net/reader035/viewer/2022073022/575098b81a28abbf6bde981b/html5/thumbnails/16.jpg)
70 NIZARDetal
pedicular fixation of the lumbar spine: Outcome eval- uation by functional tests. J Spinal Disord 12147, 1999
5. Axelsson P, Johnsson R, Stromqvist B, et al: Orthosis as prognostic instrument in lumbar fusion: No pre- dictive value in 50 cases followed prospectively. J Spinal Disord 8284,1995
6. Bednar DA, Raducan V External spinal skeletal fixa- tion in the management of back pain. Clin Orthop 322131, 1996
7. Boden S, Wiesel S Lumbosacral segmental motion in normal individuals. Have we been measuring insta- bility properly? Spine 15:571,1990
8. Boxall D, Bradford DS, Winter RB, et al: Management of severe spondylolisthesis in children and adoles- cents. J Bone Joint Surg Am 61:479,1979
9. Bram J, Zanetti M, Min K, et a1 h4R abnormalities of the intervertebral disks and adjacent bone marrow as predictors of segmental instability of the lumbar spine. Acta Radiol 39:18, 1998
10. Brechbuhler D, Markwalder TM, Braun M: Surgical results after soft system stabilization of the lumbar spine in degenerative disc disease: Long-term results. Acta Neurochir 140:521, 1998
11. Briard JL, Jegou D, Cauchoix J: Adult lumbar scolio- sis. Spine 4526,1979
12. Bridwell K, Sedgewick T, OBrien M, et al: The role of fusion and instrumentation in the treatment of degenerative spondylolisthesis with spinal stenosis. J Spinal Disord 6461,1993
13. Crisco JD, Panjabi M The intersegmental and multi- segmental muscles of the lumbar spine: A biome- chanical model comparing lateral stabilizing poten- tial. Spine 16:793, 1991
14. Daniehn 8, Frennered K, Irstam L Roentgenologic assessment of spondylolisthesis. I: A study of mea- surement variations. Acta Radiol 29:345, 1988
15. Davis H: Increasing rates of cervical and lumbar spine surgery in the United States, 1979-1990. Spine 19:1117, 1994
16. Dvorak J, Panjabi MM, Chang DG, et a1 Functional radiographic diagnosis of the lumbar spine: Flexion- extension ahd lateral bending. Spine 16:562, 1991
17. Esses SI, Botsford DJ, Kostuik J P The role of external spinal skeletal fixation in the assessment of low-back disorders. Spine 14:594, 1989
18. Faraj AA, Akasha K, Mulholland RC: Temporary ex- ternal fixation for low back pain: Is it worth doing? Eur Spine J 6187,1997
19. Farfan H The torsional injury of the lumbar spine. Spine 9:53, 1984
20. Farfan HF, Cossette JW, Robertson GH, et al: The effects of torsion on the lumbar intervertebral joints: The role of torsion in the production of disc degener- ation. J Bone Joint Surg Am 52:468,1970
21. Feffer H, Wiesel S, Cuckler J, et al: Degenerative spondylolisthesis: To fuse or not to fuse. Spine 10287,1985
22. Fox MW, Onofrio BM, Hanssen AD Clinical out- comes and radiological instability following decom- pressive lumbar laminectomy for degenerative spinal stenosis: A comparison of patients undergoing con- comitant arthrodesis versus decompression alone [see comments]. J Neurosurg 85793, 1996
23. Friberg 0: Lumbar instability: A dynamic approach by traction-compression radiography. Spine 12119, 1987
24. Graf H: Lumbar instability: Surgical management without fusion. Rachis 2123, 1992
25. Grevitt MI', Gardner AD, Spilsbury J, et al: The Graf stabilisation system: Early results in 50 patients. Eur Spine J 4169,1995
26. Grob D, Humke T, Dvorak J: Degenerative lumbar spinal stenosis: Decompression with and without arthrodesis. J Bone Joint Surg Am 771036,1995
27. Grobler L, Robertson F', Novotny J, et a1 Decompres- sion for degenerative spondylolisthesis and spinal stenosis at L4-5: The effects on facet joint morphol- ogy. Spine 18:1475, 1993
28. Grobler L, Robertson P, Novotny J, et al: Etiology of spondylolisthesis: Assessment of the role played by lumbar facet joint morphology. Spine 1880,1993
29. Hadlow SV, Fagan AB, Hillier TM, et al: The Graf ligamentoplasty procedure: Comparison with pos- terolateral fusion in the management of low back pain. Spine 23:1172,1998
30. Haher T, OBrien M, Dryer J, et al: The role of the lumbar facet joints in spinal stability: Identification of alternative paths of loading. Spine 19:2667,1994
31. Hambly MF, Wdtse LL, Raghavan N, et a1 The transi- tion zone above a lumbosacral fusion. Spine 232785, 1998
32. Hayes MA, Howard TC, Gruel CR, et al: Roentgeno- graphic evaluation of lumbar spine flexion-extension in asymptomatic individuals. Spine 14327,1989
33. Herkowitz H Spine update: Degenerative lumbar spondylolisthesis. Spine 20:1084, 1995
34. Herkowitz H, Kurz L: Degenerative lumbar spondy- lolisthesis with spinal stenosk A prospective study comparing decompression with decompression and intertransverse process arthrodesis [see comments]. J Bone Joint Surg Am 73:802, 1991
35. Hodges P, Richardson C: Inefficient muscular stabili- zation of the lumbar spine associated with low back pain: A motor control evaluation of transversus ab- dominis. Spine 21:2640, 1996
36. Jeanneret B, Jovanovic M, Magerl F Percutaneous diagnostic stabilization for low back pain: Correla- tion with results after fusion operations. Clin Orthop 3M130, 1994
37. Johnsson K, Redlund-Johnell I, Uden A, et al: Preop- erative and postoperative instability in lumbar spinal stenosis. Spine 14591,1989
38. Johnsson K, Willner S, Johnsson K Postoperative in- stability after decompression for lumbar spinal steno- sis. Spine 11:107, 1986
39. Junghanns H: Spondylolisthesis ohne spalt in Zwischengelenk stuck. Arch Orthop Unfallchir 29118-267,1930
40. Kaigle A, Holm S, Hansson T Experimental instabil- ity in the lumbar spine. Spine 20421, 1995
41. Kalebo P, Kadziolka R, Sward L: Compression- traction radiography of lumbar segmental instability. Spine 15:351, 1990
42. Kauppila LI, Eustace S, Eel DP, et al: Degenerative displacement of lumbar vertebrae: A &year follow- up study in Framingham. Spine 23:1868,1998
43. Kirkaldy-Willis W Symposium on instability of the lumbar spine: Introduction. Spine 10:254, 1985
44. Laredo J, Abi-Ayad A: Spondylolisthesis d6genCratif lombaire. In Laredo JD, Morvan G, Wybier M (eds): Imagerie OstbArticulaire. Paris, Flammarion, 1998, p 903
45. Lee CK Accelerated degeneration of the segment adjacent to a lumbar fusion. Spine 13:375, 1988
46. Lee CK, Langrana NA Lumbosacral spinal fusion: A biomechanical study. Spine 9574, 1984
47. Luoto S, Taimela S, Hurri H, et al: Mechanisms ex-
![Page 17: Radiologic Assessment of Lumbar Intervertebral Instability and Degenerative Spondylolisthesis](https://reader035.vdocuments.net/reader035/viewer/2022073022/575098b81a28abbf6bde981b/html5/thumbnails/17.jpg)
RADIOLOGIC ASSESSMENT OF LUMBAR INTERVERTEBRAL INSTABILITY 71
plaining the association between low back trouble and deficits in information processing: A controlled study with follow-up. Spine 24255, 1999
48. Luoto S, Taimela S, Hurri H, et al: Psychomotor speed and postural control in chronic low back pain patients: A controlled follow-up study. Spine 212621, 1996
49. Macnab I: The traction spur: An indicator of segmen- tal instability. J Bone Joint Surg Am 53663, 1971
50. Mardjetko S, Connolly P, Shott S Degenerative lum- bar spondylolisthesis: A meta-analysis of literature 1970-1993 [see comments]. Spine 19:2256S, 1994
51. Markwalder TM, Merat M The lumbar and lumbosa- cral facet-syndrome: Diagnostic measures, surgical treatment and results in 119 patients. Acta Neurochir 12840,1994
52. Matsunaga S, Sakou T, Morizono Y, et a1 Natural history of degenerative spondylolisthesis: Pathogene- sis and natural course of the slippage. Spine 15:1204, 1990
53. McCullen G, Bemini P, Bemstein S, et al: Clinical and roentgenographic results of decompression for lumbar spinal stenosis. J Spinal Disord 7380,1994
54. Meyerding H Spondylolisthesis: Surgical treatment and results. J Surg Gynecol Obstet 54:371, 1932
55. Newman P, Stone K The etiology of spondylolis- thesis. J Bone Joint Surg Br 45:39,1963
56. Panjabi M: The stabilizing system of the spine. Part I Function, dysfunction, adaptation, and enhance- ment. J Spinal Disord 5383,1992
57. Panjabi M: The stabilizing system of the spine. Part I1 Neutral zone and instability hypothesis. J Spinal Disord 5390, 1992
58. Panjabi MM, Goel VK, Takata K: Physiologic strains in the lumbar spinal ligaments: An in vitro biome- chanical study. 1981 Volvo Award in Biomechanics. Spine 7192, 1982
59. Paris SV Physical signs of instability. Spine 10277, 1985
60. Parlier-Cuau C, Wybier M, Nizard R, et ak Symptom- atic lumbar facet joint synovial cysts: Clinical assess- ment of facet joint steroid injection after 1 and 6 months and long-term follow-up in 30 patients. Radi- ology 210:509, 1999
61. Pearcy M: Stereoradiography of lumbar spine mo- tion. Acta M o p Scand 561,1985
62. Pitkanen M, Manninen H, Lindgrer K, et a1 Limited usefulness of traction-compression films in the radio- graphic diagnosis of lumbar spinal instability: Com- parison with flexion-extension films. Spine 22193, 1997
63. Pope M, Panjabi M: Biomechanical definitions of spi- nal instability. Spine 10955, 1985
64. Posner I, White AAD, Edwards WT, et al: A biome- chanical analysis of the clinical stability of the lumbar and lumbosacral spine. Spine 7374,1982
65. Putto E, Tallroth K Extension-flexion radiographs for motion studies of the lumbar spine: A comparison of two methods. Spine 15:107,1990
66. Rask 8, Dall BE: Use of the pantaloon cast for the
selection of fusion candidates in the treatment of chronic low back pain. Clin Orthop 288:148, 1993
67. Reust P, Wendling D, Lagier R, et al: Degenerative spondylolisthesis, synovial cyst of the zygapophyseal joints, and sciatic syndrome: Report of two cases and review of the literature. Arthritis Rheum 31:288,1988
68. Robertson P, Grobler L, Novotny J, et al: Postopera- tive spondylolisthesis at L4-5 The role of facet joint morphology. Spine 181483,1993
69. Sat0 H, Kikuchi S: The natural history of radio- graphic instability of the lumbar spine. Spine 18:2075, 1993
70. Sharma M, Langrana N, Rodriguez J: Role of liga- ments and facets in lumbar spinal stability. Spine 20887,1995
71. Sienkiewiu PJ, Flatley 'IJ: Postoperative spondylolis- thesis. Clin Orthop 221:172,1987
72. Soini J, Antti-Poika I, Tallroth K, et al: Disc degenera- tion and angular movement of the lumbar spine: Comparative study using plain and flexion-extension radiography and discography. J Spinal Disord 4983, 1991
73. Stokes I, Frymoyer J: Segmental motion and instabil- ity. Spine 12688,1987
74. Taillard WF Les spondylolisthesis chez l'enfant et l'adolescent. Acta Orthop Scand 24:115-144, 1955
75. Tallroth K, Alaranta H, Soukka A: Lumbar mobility in asymptomatic individuals. J Spinal Disord 5:481, 1992
76. Tassin J, Defives T, Despres N: Dislocation arthro- sique des scolioses lombaires de l'adulte. In Buol B, Simon L (eds): Masson: La Scoliose Lombaire de Uadulte. Paris, Masson, 1990, p 46
77. Tokuhashi Y, Matsuzaki H, Sano S Evaluation of clinical lumbar instability using the treadmill. Spine 18:2321, 1993
78. Turner JA, Ersek M, Herron L, et a1 Patient outcomes after lumbar spinal fusions. Jama 268907,1992
79. van der Schaaf DB, van Limbeek J, Pavlov PW Tem- porary external transpedicular fixation of the lumbo- sacral spine. Spine 24481,1999
80. van Tulder M, Assendelft W, Koes B, et al: Spinal radiographic findings and nonspecific low back pain: A systematic review of observational studies. Spine 22:427, 1997
81. Vogt M, Rubin D, Valentin R, et ak Lumbar olisthesis and lower back symptoms in elderly white women: The Study of Osteoporotic Fractures. Spine 232640, 1998
82. Vol i i E, Mayer J, Diehr P, et al: Small area analysis of surgery for low-back pain. Spine 17575, 1992
83. Yone K, Sakou T Usefulness of Posner's definition of spinal instability for selection of surgical treatment for lumbar spinal stenosis. J Spinal Disord 1240,1999
84. Yone K, Sakou T, Kawauchi Y, et ak Indication of fusion for lumbar spinal stenosis in elderly patients and its significance. Spine 21:242,1996
85. Yong-Hing K, Kirkaldy-Willis WH The pathophysi- ology of degenerative disease of the lumbar spine. Orthop Clin North Am 14:491,1983
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R6my S. Nizard, MD, PhD Department of Orthopaedic Surgery
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