Apparent regeneration of the mandibular canal in a free bone graft

Apparent regeneration of the mandibular canal in a free bone graft Colin Hopper, FDS, FRCS(Edin),” Sussex, England

and Ian D. Poker, MDSc, FRACDS, FFD,b

THE QUEEN VICTORIA HOSPITAL A case is presented of recanalization of the inferior alveolar canal in a nonvascularized years after mandibular resection with preservation of the inferior alveolar nerve. (ORAL SURC ORAL MED ORAL PATHOL 1990;70:431-2)

B

ecker’ in 1970 described resection of the mandible with preservation of the inferior alveolar nerve, which was then inset into a free bone graft. Subsequently, a variety of descriptions of nerve repositioning procedures for many clinical conditions have appeared.*, 3 The ultimate position of the nerve is relevant when implants are placed in free bone grafts at a later date to complete the reconstruction.

bone graft some 4

mately 3 months, the sensation in the lower lip returned to normal. The patient was kept under regular review, and 4 years later an obvious mandibular canal was demonstrated radiographically within the graft (Fig. 3). Because this might merely represent a grooving of the outer cortex of bone, a posteroanterior radiograph was taken to help locate the mediolateral position of the canal. This investigation was not diagnostic, and a computed tomographic scan was

CASEREPORT

An 18-year-old girl had a S-year history of swelling of the left mandible. A biopsy was performed, which suggestedthe condition was a fibro-osseous lesion although the clinical behavior was suggestiveof a more aggressivelesion (Fig. 1). Therefore the patient underwent a conservative hemimandibulectomy with immediate restoration of mandibular continuity with a free iliac crest bone graft (Fig. 2). The inferior alveolar nerve was exteriorized and left to lie subperiosteally. Postoperatively, over a period of approxiSenior Registrar. bRegistrar in Oral and Maxillofacial Surgery.

Fig. 2. Immediate postoperative radiograph showing position bf free iliac crest bone graft.

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Fig.

1. Fibro-osseous lesion at left angle of mandible.

Fig. 3. Radiograph 4 years after operation. Clearly defined mandibular canal can now be seen. 431

432

Hopper and Poker

ORAL SURG ORAL MED ORAL PATHOL

October 1990

considered not to be indicated unless formal reconstruction was to be contemplated.4 Thus far, the patient has steadfastly refused any further surgery. DISCUSSION

The finding of a new mandibular canal was surprising. It is, however, not entirely unexpected, inasmuch as at the original operation the nerve was isolated and left beneath the periosteum. It is suggested that if implants are to be considered in this type of case, then plain radiology supplemented with computed tomographic scanning may be required to avoid damage to the neurovascular bundle. We thank Mr. Michael Awty for permission to report this case.

REFERENCES 1. Becker R. Continuity resection of the mandible with preservation of the mandibular nerve. Br J Oral Surg 1970;8:45-50. 2. Ailing C. Lateral repositioning of the inferior alveolar neurovascular bundle. J Oral Surg 1977;35:419. 3. Jensen 0, Neck D. Inferior alveolar nerve repositioning in conjunction with placement ofosseointegrated implants: a case report. ORAL SURG ORAL MED ORAL PATHOL 1987;63:263-8. 4. Tamas F. Position of the mandibular canal. Int J Oral Maxillofac Surg 1987;16:65-9. Reprint requests to: Dr. Colin Hopper Senior Registrar The Queen Victoria Hospital Holtye Road East Grinstead Sussex, England RH19 3D2