September 2012 A.E. Abdulai Complete spontaneous bone regeneration COMPLETE SPONTANEOUS BONE REGENERATION FOLLOWING PARTIAL MANDIBULECTOMY A. E. ABDULAI Department of Oral and Maxillofacial Surgery, University of Ghana Dental School, Korle Bu Teaching Hospital. P. O. Box 77, Accra, Ghana. Corresponding Author: Dr. A. E. Abdulai E-mail address: aemilabdulai@yahoo.com Conflict of Interest: None declared SUMMARY mandibular fixation (MMF)7, 9, Kirschner wire1 or tita- 8 Bone formation in small deposits following the loss of nium mesh was employed in the surgery. Several ex- part of the mandible has often been reported in the lit- planations for this remarkable phenomenon have been erature, but reports of complete bone regeneration ex- proposed and include the development of new bone 3-10 1,10 tending over the entire anterior mandible from angle to from intact periosteum or its fragments which angle is rare. Even rarer, are reports on the behaviour serve as the direct source of osteogenic cells, and from 2 of such new bone in terms of facial development, over regenerated juvenile periosteum. a long term and the effect of load carrying on it. Pre- sented here is an unusual case of bone regeneration Presented in this report, is yet another case of sponta- after resection of a large portion of the mandible in a neous bone regeneration of the mandible after partial 12 year-old female patient with ameloblastoma in the mandibulectomy in a 12 -year-old female patient for anterior mandible. Inter-maxillary fixation, bone graft- the treatment of ameloblastoma. Long term follow-up ing, or insertion of any kind of implant was not em- of regenerated mandible is rare in the literature. The ployed. Spontaneous bone regeneration was noted six purpose of this report is to highlight the course and weeks after surgery, and the entire resected portion of behaviour of the regenerated bone over a period of thir- the mandible completely regenerated when the patient teen years, including five years of partial denture usage was seen again six years later. Mandibular growth was over the new bone. Though the periosteum was care- not significantly affected and thirteen years after her fully preserved as in many others reported, in this case treatment, including five years of partial denture usage no bone graft or implant was used, and no form of sta- over the new bone, the shape of the mandible is satis- bilization was employed during the healing period. factory without any evidence of bone resorption. The periosteum was totally preserved, perhaps accounting CASE REPORT for the complete bone regeneration and normal man- Clinical Examination dibular growth and form. A 12-year old girl child (M.A.) was referred for evalua- tion of her jaw swelling that had been noticed, and had Key Words: Mandibulectomy; Complete; Spontane- grown slowly over a year. General examination re- ous; Bone; Regeneration. vealed an otherwise healthy child with her haemogram and blood chemistry within normal range. Aspiration INTRODUCTION of the lesion produced a slimy sero-sanguineous fluid, Spontaneous bone regeneration following the loss of and a posterior-anterior view of radiograph of the jaws part or the entire mandible has occasionally been re- (Figure1) showed a cloudy expansion of the mandible ported in the literature. The causes of reported exten- from the angle region on the right to the premolar re- sive bone loss include shot gun blast injury1,2, enuclea- gion on the left, with the lower right mandibular canine tion of large cysts3,4 and infection.5-7 By far however, inferiorly displaced. A clinical diagnosis, later con- the commonest reported cause of extensive bone loss firmed histologically, as ameloblastoma was made. has been as a result of partial mandibulectomy6-10 for Immediate pre-operative findings revealed an extensive the treatment of a tumour or tumour-like condition. A tumour involving the entire anterior mandible, necessi- search on the World Wide Web reveals only a total of tating total resection despite her age. twenty cases of spontaneous mandibular bone regen- eration reported in the English literature by the end of Surgical Procedure the 2007. Only three of these cases were adults above Under general anaesthesia, an extra-oral surgical ap- 32 years. The rest were child patients with ages ranging proach via a sub-mandibular incision was performed. from 8 to 15 years. In most of the reported cases, some The tumour was exposed by blunt dissection and the kind of stabilization in the form of a maxillo- periosteum neatly cut along the lower mandibular bor- 17 4 September 2012 Volume 46, Number 3 GHANA MEDICAL JOURNAL der in the direction of the surgical incision and care- fully stripped off on both sides of the mandible, thus entirely exposing the tumour, which was then com- pletely resected. The periosteum was carefully sutured back in place and the wound closed in layers without inserting any drain, graft or implant. She was placed on one mega-unit crystalline penicillin six hourly, I.V/I.M for a week. Figure 3 Photograph of patient showing close-up view of partial denture fitted in place It was evident then that the patient’s facial develop- ment was consistent with her age. Thirteen years after her treatment despite the weight carried on the regener- ated bone, from the use of the denture, there is no evi- dence of bone resorption, and the shape of the mandi- Figure 1.Radiograph showing posterior-anterior view ble is satisfactory with no evidence of recurrence. (Fig- of the jaws. Note the displaced right mandibular canine ure 4) and the extent of the lesion at presentation. Postoperative Course This was uneventful, and the patient was discharged home after 10 days. Interestingly, when she was re- viewed six weeks post op, bone regeneration was noted following a bimanual palpation of some firm callus- like tissue replacing the resected mandible. This was remarked in her notes and she was scheduled for fur- ther review and post op x-ray, but then she failed to keep the appointment and got lost to follow-up. At 18, six years after her operation, she reappeared to request for a partial denture to replace her missing teeth. The mandible, at that time, appeared completely Figure 4 Photograph of the patient, (M.A.) 13 years regenerated following a review of a radiograph, (Figure post-op showing a partial denture fitted in place. Note 2), taken to assess her for the construction of the partial the satisfactory development and shape of the mandi- denture (Figure 3). ble. DISCUSSION Spontaneous bone regeneration, an unexpected phe- nomenon that may take place following the loss of part or the entire mandible, has occasionally been reported in the literature. The reported causes of such extensive bone loss have included shot gun blast injury1,2, enu- cleation of large cysts3,4 and infection.5-7 The common- est reported cause of extensive bone loss however, has 6-10 Figure 2 Orthopantomograph of the mandible taken six been as a result of partial mandibulectomy for the years post operative. Note the completely regenerated treatment of a tumour or tumour-like condition. bone. Glenda H. de Villa et al8 presented, including their own, a total of 19 reports of spontaneous bone regen- eration of the mandible in the English literature up to 17 5 September 2012 A.E. Abdulai Complete spontaneous bone regeneration the year 2002. In all of those reports, authors reported This was found to be the case in the patient reported resecting a large portion of the mandible or repairing here. Her entire anterior mandibular segment was re- the remaining mandibular segments after an injury placed with new bone that was well formed and posi- without expecting any bone regeneration to take place tioned. in such a large gap. New bone was discovered only during routine postoperative clinical and radiographic Long-term follow-up of regenerated mandible is rare in examinations. Nagase9 et al, noted eggshell radiopac- the literature. The longest before now was a 5-year ity in the area of a resected condyle in an orthopanto- follow-up of a regenerated mandible presented by Bu- mogram taken 2 weeks postoperatively, Whiles Budal5 dal.5 It showed bone regeneration from the right third reported new bone formation between remaining man- molar to the left second molar. A situation quite akin to dibular stumps 2 weeks after resection of a large os- that reported here. teofibroma. A review of the literature presents several factors that may influence this process, and several As seen in Figure 2, there was no interruption in the suggestions by various authors have been put forward connection between the old and the new bone. A simi- in an attempt to explain this phenomenon. lar observation was made in a recent report, 10 where although there was no external sign of disfigurement, For instance both Adekeye6 and Nwoku7 suggested in the new mandible was apparently deformed in the area their reports that preservation of periosteum, coupled where the ramus had been pulled upward before the with the young ages of their patients, possible genetic formation of new bone. Such observation according the factors and infection may play important roles in rapid authors, demonstrates that the newly regenerated bone bone regeneration. Pramono,10 more recently, reported behaved in a manner similar to that of the original yet another case of spontaneous bone regeneration, bone, and lead them to conclude in their report that an and went on to suggest that unexpected spontaneous explanation for this unexpected bone regeneration may bone regeneration may be explained by the fact that be derived from the mechanism of fracture healing. periosteum, as the source of osteogenic cells, might be The difference according to them is that the former responsible for this process. Other factors mentioned in process takes place in a large mandibular defect, the literature include the presence of bony fragments,1, 2 whereas the latter occurs when the bony segments are and of a temporary reconstruction material such as tita- placed in close contact with each other and fixed. nium mesh8, 9 or Kirschner wire.1,2 In conclusion, the uninterrupted connection between The patient reported here was treated for Ameloblas- the old and new bone and the lack of vertical height toma of the mandible, for which various surgical meth- loss in the new bone, despite the use of a denture over ods, both conservative and radical, could be used. The it for over five years in the case reported here, lays treatment method chosen in this case was influenced by further credence to the fact that the newly regenerated factors such as the nature of presentation of the tumour, bone behaves in a manner similar to that of the original including the large extent and degree of bone involve- bone, and that its regeneration may be derived from the ment with tumour, the age of the patient and the limited mechanism of fracture healing, with intact periosteum resources including the lack of any form of reconstruc- being essentially necessary. tion material and or the means to acquire it at the time. Six weeks after her surgery, bone regeneration was REFERENCES noted in the firm callus-like tissue replacing the re- 1. Kisner WH. Spontaneous posttraumatic mandibu- sected mandible. lar regeneration. Plast Reconstr Surg 1980; 66:442-7. The young age of the patient, coupled with the preser- 2. Shuker S. Spontaneous regeneration of the mandi- vation of the periosteum as already suggested by some ble in a child. A sequel to partial avulsion as a re- previous reports6, 7,10, are some of the factors that could sult of a war injury. J Maxillofac 1985 Apr; have contributed to this phenomenon. Unlike in most 13(2):70-3. of the reports however, no significant infection6,7 was 3. Chiapasco M, Rossi A, Motta JJ, Crescentini M. encountered here, and no form of maxillomandibular Spontaneous bone regeneration after enucleation fixation (MMF) 7, 9, Kirschner wire1, or titanium mesh8 of large mandibular cysts: a radiographic com- was employed in the surgery. puted analysis of 27 consecutive cases. J Oral Maxillofac Surg. 2000 Sep;58(9):942-8 Kisner1 reported that the regenerated mandible in his 4. Di Dio M, De Luca M, Cammarata L, Pierazzi G. patient had attempted to replace the missing segment Bone regeneration after removal of a mandibular not only in substance but in position as well. cyst and following prosthetic rehabilitation with 17 6 September 2012 Volume 46, Number 3 GHANA MEDICAL JOURNAL implants. Case report. Minerva Stomatol. 2005 Case Report and Review of the Literature. Chang Jun; 54(6):373-8. Gung Med J 2003; 26:363-9. 5. Budal J. The osteogenic capacity of periosteum. 9. Nagase M, Ueda K, Suzuki I, Nakajima T. Spon- Oral Surg 1979; 47:227-9. taneous regeneration of the condyle following 6. Adekeye EO. Rapid bone regeneration subsequent hemimandibulectomy by disarticulation. J Oral to subtotal mandibulectomy. Oral Surg 1977; Maxillofac Surg 1985; 43:218-220. 44:521-6. 10. Pramono D Coen. Spontaneous bone regeneration 7. Nwoku AL. Unusually rapid bone regeneration after mandible resection in a case of ameloblas- following mandibular resection. J Maxillofac Surg toma: A case report. Annals of the Academy of 1980; 8:309-15. Medicine, Singapore. 2004, Jul; 33(4 Suppl):59- 8. Glenda H. de Villa, et al Spontaneous bone regen- 62. eration of the Mandible in an Elderly Patient: A 17 7 September 2012 A.E. Abdulai Complete spontaneous bone regeneration 2