Bilateral sagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft

Abstract

We report a bilateral sagittal split osteotomy (BSSO) in a reconstructed mandible. A 28-year-old woman underwent a segmental mandibulectomy due to a multicystic ameloblastoma in the left jaw. After primary plate reconstruction, final reconstruction was performed with a left posterior iliac crest cortico-cancellous autograft. Due to a pre-existing Class II malocclusion, the patient was analyzed for combined orthodontic–surgical treatment. Subsequently, after 1 year of orthodontic treatment, the BSSO was planned. The sagittal split was performed in the remaining right mandible and on the left side in the iliac crest cortico-cancellous autograft. Ten months later, oral rehabilitation was completed with implant placement in the neomandible. Follow-up showed a Class I occlusion, with good function. The patient was very satisfied with the functional and aesthetic results. This case shows that a BSSO can be performed in a reconstructed mandible, without side effects and with good functional and aesthetic results.

A bilateral sagittal split osteotomy (BSSO) is a procedure used frequently for the correction of a Class II malocclusion. Although the technique still presents a certain degree of technical difficulty, it has become a reliable procedure in orthognathic surgery. Reports of BSSO in a mandible reconstructed with a non-vascularized bone graft after hemimandibulectomy (because of an ameloblastoma), have not been published previously.

Multicystic ameloblastoma (MA) is an uncommon benign odontogenic neoplasm of the jaws. This cystic tumour is most often found in the mandible, in the region of the molars and ramus. Ameloblastomas usually progress slowly, but are locally invasive and, uncontrolled, may cause significant morbidity and sometimes death. MA is the most common ameloblastoma and is considered the most aggressive variant. As curative treatment, a segmental mandibulectomy with a 1- to 1.5-cm linear bony margin is the treatment of choice in these cases.

After (partial) resection of the mandible due to large benign tumours, reconstruction is necessary. Several reconstructive procedures, such as vascularized and non-vascularized bone flaps, can be considered. A common technique is reconstruction with a non-vascularized iliac crest bone graft.

After mandibular reconstruction, oral rehabilitation can be completed with implant placement. High survival and success rates have been reported after implant placement in autogenous bone grafts, with an excellent prognosis for implant-supported prostheses.

This study reports a case of a BSSO in combination with implant rehabilitation in the non-vascularized iliac crest bone graft in a 33-year-old woman, after hemimandibulectomy due to a MA.

Case report

A healthy, 28-year-old, female patient was diagnosed with a follicular-type MA in the body of the mandible, near the mandibular angle on the left side ( Fig. 1 ). The patient underwent a segmental mandibulectomy, starting between the first and second premolar to the ramus, with preservation of the left condyle.

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

Primary reconstruction was performed with a plate (UniLOCK Plate 2.4, angled, TiCP, SYNTHES, Oberdorf, Germany). Seven months later, after recovery and confirmation of clear pathological margins, the mandible was reconstructed as described by Marx. Restoration of the left hemimandible was performed with a left posterior iliac crest cortico-cancellous autograft. The defect of the mandible was measured (17 mm × 56 mm) preoperatively, using an orthopantomogram (OPT). Via extra-oral approach, the initial reconstruction plate was visualized and freed, because it had been fractured due to trauma. A new similar plate was placed to support and fixate the bone graft. The cortico-cancellous graft was adjusted to the lingual side of the plate and kept in place by primary closure of the soft tissues in several layers. Recovery was uneventful and the graft consolidated in a slightly inferior position ( Fig. 2 ).

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

Postoperative follow-up showed a pre-existing Class II malocclusion with traumatic gingival recession in the maxillary incisors and generalized periodontitis ( Figs 3 and 4 ). The second molar in the upper left jaw was absent. The second premolar and first molar of the upper left jaw showed no occlusion because of missing antagonists after the hemimandibulectomy.

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

Fig. 4
Photograph taken before BSSO, showing the contour of the successfully reconstructed mandible, resulting in a Class II profile, with a shortened vertical length of the face.

Due to her Class II malocclusion with palatal soft tissue trauma, the patient was analyzed for a combined orthodontic–surgical treatment and occlusal rehabilitation with implants. A radiographic examination in preparation for the BSSO showed a bony union of the cortico-cancellous graft, diffuse periodontal reduction of bone, and an impacted third molar in the right mandible. Initial treatment of the periodontitis was started.

Preceding the orthognathic surgery, 1 year before to the BSSO, the reconstruction plate was removed, combined with remodelling of the left hemimandible with autogenous bone from the right anterior iliac crest and removal of the impacted third molar ( Fig. 5 ). After successful treatment and stabilization of the periodontitis, staged orthodontic and surgical treatment was initiated to restore occlusion and prevent further palatal and periodontal trauma.

Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Bilateral sagittal split osteotomy in a mandible previously reconstructed with a non-vascularized bone graft
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