Case Report

Orthognathic Surgery

Int. J. Oral Maxillofac. Surg. 2013; 42: 830–834http://dx.doi.org/10.1016/j.ijom.2013.01.019, available online at http://www.sciencedirect.com

Bilateral sagittal split osteotomyin a mandible previouslyreconstructed with a non-vascularized bone graftG. Mensink, J. P. Verweij, P. J. J. Gooris, J. P. R. van Merkesteyn: Bilateralsagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft. Int. J. Oral Maxillofac. Surg. 2013; 42: 830–834. # 2013International Association of Oral and Maxillofacial Surgeons. Published by ElsevierLtd. All rights reserved.

Abstract. We report a bilateral sagittal split osteotomy (BSSO) in a reconstructedmandible. A 28-year-old woman underwent a segmental mandibulectomy due to amulticystic ameloblastoma in the left jaw. After primary plate reconstruction, finalreconstruction was performed with a left posterior iliac crest cortico-cancellousautograft. Due to a pre-existing Class II malocclusion, the patient was analyzed forcombined orthodontic–surgical treatment. Subsequently, after 1 year of orthodontictreatment, the BSSO was planned. The sagittal split was performed in the remainingright mandible and on the left side in the iliac crest cortico-cancellous autograft. Tenmonths later, oral rehabilitation was completed with implant placement in theneomandible. Follow-up showed a Class I occlusion, with good function. Thepatient was very satisfied with the functional and aesthetic results. This case showsthat a BSSO can be performed in a reconstructed mandible, without side effects andwith good functional and aesthetic results.

0901-5027/070830 + 05 $36.00/0 # 2013 International Association of Oral and Maxillofacial Surge

G. Mensink1,2, J. P. Verweij1,P. J. J. Gooris2,J. P. R. van Merkesteyn1

1Department of Oral and MaxillofacialSurgery, Leiden University Medical Centre,Leiden, The Netherlands; 2Department ofOral and Maxillofacial Surgery, AmphiaHospital, Breda, The Netherlands

Key words: Bilateral sagittal split osteotomy;reconstruction; ameloblastoma.

Accepted for publication 28 January 2013Available online 27 February 2013

A bilateral sagittal split osteotomy(BSSO) is a procedure used frequentlyfor the correction of a Class II malocclu-sion. Although the technique still presentsa certain degree of technical difficulty, ithas become a reliable procedure in orthog-nathic surgery. Reports of BSSO in amandible reconstructed with a non-vascu-larized bone graft after hemimandibulect-omy (because of an ameloblastoma), havenot been published previously.

Multicystic ameloblastoma (MA) is anuncommon benign odontogenic neoplasmof the jaws. This cystic tumour is most

often found in the mandible, in the regionof the molars and ramus. Ameloblastomasusually progress slowly, but are locallyinvasive and, uncontrolled, may causesignificant morbidity and sometimesdeath. MA is the most common amelo-blastoma and is considered the mostaggressive variant. As curative treatment,a segmental mandibulectomy with a 1- to1.5-cm linear bony margin is the treatmentof choice in these cases.1

After (partial) resection of the mandibledue to large benign tumours, reconstruc-tion is necessary. Several reconstructive

procedures, such as vascularized and non-vascularized bone flaps, can be consid-ered.2,3 A common technique is recon-struction with a non-vascularized iliaccrest bone graft.4

After mandibular reconstruction, oralrehabilitation can be completed withimplant placement. High survival and suc-cess rates have been reported after implantplacement in autogenous bone grafts, withan excellent prognosis for implant-sup-ported prostheses.5

This study reports a case of a BSSO incombination with implant rehabilitation in

ons. Published by Elsevier Ltd. All rights reserved.

Bilateral sagittal split osteotomy 831

Fig. 1. Three-dimensional image of the multicystic ameloblastoma in the body and angle of theleft hemimandible.

Fig. 2. Three-dimensional image of the mandible after reconstruction with a plate andautologous bone from the left posterior iliac crest. The cortico-cancellous autograft consolidatedin a slightly inferior position.

the non-vascularized iliac crest bone graftin a 33-year-old woman, after hemiman-dibulectomy due to a MA.

Case report

A healthy, 28-year-old, female patient wasdiagnosed with a follicular-type MA in thebody of the mandible, near the mandibularangle on the left side (Fig. 1). The patientunderwent a segmental mandibulectomy,starting between the first and second pre-molar to the ramus, with preservation ofthe left condyle.

Primary reconstruction was performedwith a plate (UniLOCK Plate 2.4, angled,TiCP, SYNTHES, Oberdorf, Germany).Seven months later, after recovery andconfirmation of clear pathological mar-gins, the mandible was reconstructed asdescribed by Marx.4 Restoration of the lefthemimandible was performed with a leftposterior iliac crest cortico-cancellousautograft. The defect of the mandiblewas measured (17 mm � 56 mm) preo-peratively, using an orthopantomogram(OPT). Via extra-oral approach, the initialreconstruction plate was visualized andfreed, because it had been fractured dueto trauma. A new similar plate was placedto support and fixate the bone graft. Thecortico-cancellous graft was adjusted tothe lingual side of the plate and kept inplace by primary closure of the soft tissuesin several layers. Recovery was unevent-ful and the graft consolidated in a slightlyinferior position (Fig. 2).

Postoperative follow-up showed a pre-existing Class II malocclusion with trau-matic gingival recession in the maxillaryincisors and generalized periodontitis(Figs 3 and 4). The second molar in theupper left jaw was absent. The secondpremolar and first molar of the upper leftjaw showed no occlusion because of miss-ing antagonists after the hemimandibu-lectomy.

Due to her Class II malocclusion withpalatal soft tissue trauma, the patient wasanalyzed for a combined orthodontic–sur-gical treatment and occlusal rehabilitationwith implants. A radiographic examina-tion in preparation for the BSSO showed abony union of the cortico-cancellous graft,diffuse periodontal reduction of bone, andan impacted third molar in the right mand-ible. Initial treatment of the periodontitiswas started.

Preceding the orthognathic surgery, 1year before to the BSSO, the reconstruc-tion plate was removed, combined withremodelling of the left hemimandible withautogenous bone from the right anterioriliac crest and removal of the impacted

third molar (Fig. 5). After successful treat-ment and stabilization of the periodontitis,staged orthodontic and surgical treatmentwas initiated to restore occlusion and pre-vent further palatal and periodontaltrauma.

After uneventful healing, the patientwas planned for orthognathic treatment,5 years after the first operation. A bilateralsagittal ramus split on the right side wasperformed, with the use of sagittal splittersand separators instead of chisels, as first

described by van Merkesteyn et al.6 andMensink et al.7 In the neomandible, thedistal end of the iliac crest graft was foundto be the site with the highest bone qualityand quantity, therefore the split wasplanned in this section of the mandible.Horizontal, sagittal, and vertical cuts weremade with a saw (sagittal cut) and Linde-man burr (horizontal and vertical cut), andthe split was completed with chisels incombination with sagittal splitters andseparators. Chisels were necessary due

832 Mensink et al.

Fig. 3. Lateral cephalogram taken 1 month before bilateral sagittal split osteotomy, showing apre-existing class 2 malocclusion.

to the small consistent cortical bone, andcould be used because of the absence ofthe inferior alveolar nerve after hemiman-dibulectomy. After complete mobilizationof the proximal and distal parts, the mand-ible was placed into the new intermaxil-lary relationship using a wafer, andintermaxillary wire fixation was applied.

After precise placement of the proximalsegments, with normal clinical support ofthe temporomandibular joints, the rightside was fixated with three bicorticalscrews in the upper border of the mand-ible. The iliac crest graft was then fixatedwith two bicortical screws. After removalof the temporary intermaxillary fixation, a

Fig. 4. Photograph taken before BSSO, show-ing the contour of the successfully recon-structed mandible, resulting in a Class IIprofile, with a shortened vertical length ofthe face.

new symmetrical Class I occlusion wascreated (Figs 6 and 7).

Three months after the BSSO, the initialstage of implant treatment took place. Twosubmucosal implants (length 13 mm, dia-meter 3.8 mm; Branemark, Nobel Bio-care, Houten, The Netherlands) wereplaced in the position of the former secondpremolar and first molar of the left mand-ible. Seven months after implant place-ment, the implants were recovered to placetwo healing abutments. Subsequently the

Fig. 5. Three-dimensional image of the reconstrtion plate and remodelling of the left hemimandibiliac crest.

prosthetic phase started, after healing ofthe wound.

From the first operation to the Class Iocclusal rehabilitation took about 6 years.At the last follow-up, the patient had goodfunction and was satisfied with the results.

Discussion

The different treatment options forpatients with ameloblastoma range fromenucleation and curettage to more radicalsurgical management, such as marginal orsegmental resection. MAs are moreaggressive and associated with a higherrate of recurrence in comparison withunicystic or peripheral ameloblastomas.1

MAs of the follicular type show thehighest percentage of recurrence. As thispatient was diagnosed with an MA of thefollicular type, radical surgical manage-ment was indicated. A segmental mandi-bulectomy with histopathologically clearbony margins is the most effective meansto prevent recurrence and was thereforethe treatment of choice in this case.1

After segmental resection of the mand-ible, different methods of reconstructioncan be chosen. The two most frequentlyused techniques are reconstruction with avascularized bone flap (VBF), or a non-vascularized bone graft (NVBG). VBF,often in the form of a vascularized fibular

ucted mandible after removing the reconstruc-le with autologous bone from the right anterior

Bilateral sagittal split osteotomy 833

Fig. 6. Lateral cephalogram showing a class 1 occlusion after bilateral sagittal split osteotomyand subsequent implant placement.

free flap, is the most commonly usedtechnique for reconstruction, with highsuccess rates and high endosseousimplant success.8 In patients with priorradiation therapy or very large defects(>60 mm), reconstruction with a VBGis the therapy of choice, because thesefactors significantly decrease the successrates of NVBG.9

However, NVBG are widely used aswell, and can be very useful, especiallyin secondary reconstructions. Non-vascu-larized bone grafts allow for an easierreconstruction, with higher functional suc-cess, and create a better contour and bonevolume for facial aesthetics and subse-quent implant insertion than VBF.9,10 In

Fig. 7. Photograph taken after BSSO, show-ing a Class I profile as a result of the operation,with a normalized vertical length of the face.

this case, no prior radiation therapy wasnecessary because of the nature of thetumour, and the mandibular defect wasless than 60 mm.

Primary reconstruction with a plate wasperformed in order to be able to confirmclear bony margins histopathologicallybefore secondary reconstruction. Owingto the mentioned advantages, secondaryreconstruction was subsequently donewith a non-vascularized iliac crest poster-ior autograft.

The most common complication afterBSSO is damage to the inferior alveolarnerve, resulting in neurosensory distur-bances of the lip and/or chin, also knownas hypoesthesia. In this patient, hypoesthe-sia was already present on the left side dueto the previous hemimandibulectomy.This made the use of chisels in additionto our conventional technique favourable,because of the small cortical bone in theiliac crest autograft. On the right side, theinferior alveolar nerve was not damagedusing only sagittal splitters and separators,and no hypoesthesia was present after theBSSO. Other complications after BSSO,such as bad splits, infection, non-union,bleeding complications, and osteomyelitisare not very frequent and were not presentin this patient.

Oral rehabilitation with implant place-ment is often an important part of thedental reconstruction after mandibularreconstruction and helps prevent the recur-rence of malocclusion. High success andsurvival rates after implant placement inbone grafts have been reported.8

Dental implants placed in a non-vascu-larized bone graft provide a reliable basisfor dental rehabilitation.5 The timing ofimplant placement is normally several

months (3–4 months) after bone augmen-tation or reconstruction. In this caseimplant placement concomitant withBSSO was considered, but postoperativeimplant placement was preferred becauseof the altered position of the mandibleafter BSSO. When the patient discoveredshe was pregnant, placement of dentalimplants was delayed. Dental implantplacement was nevertheless necessarybecause of the proceeding bone reductionand was thus commenced later thanplanned, after more than 5 months ofpregnancy.

In our patient, occlusion Class Iremained present after BSSO, with goodfunctional and aesthetic results. Hypoesthe-sia on the left side was pre-existing, follow-ing the hemimandibulectomy, andhypoesthesia was absent on the right side.No other complications after BSSO werepresent, and successful implant placementresulted in full oral rehabilitation. Thisshows that BSSO can be performed in areconstructed mandible with no side effectsand a good result.

Funding

None.

Competing interests

None.

Ethical approval

Not required.

Acknowledgements. The authors gratefullyacknowledge O. Ruygrok (Department ofRadiology, Leiden University MedicalCentre) for the 3D imaging in this caseand E. M. Boerrigter for her role throughthe course of implant placement.

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Address:Gertjan MensinkDepartment of Oral and Maxillofacial

SurgeryAmphia HospitalMolengracht 21Postbus 901584800 RKBredaThe NetherlandsTel: +31 765953111;Fax: +31 765953430E-mail: GMensink1@amphia.nl