Immediate reconstruction of the mandible after resection for aggressive odontogenic tumours: a cohort study

Abstract

The results are reported of a clinical follow-up study on 32 selected but consecutive patients with mandibular ameloblastoma. They were all treated by a segmental resection and reconstructed, using two 2.3 mm reconstruction plates and an autogenous particulate bone graft, taken from the anterior iliac crest, and platelet rich plasma. Follow-up ranged from 12 to 39 months, with an average of 27.9 months. Undisturbed healing occurred in 29 patients, while three had postoperative infections, but in only one case did that result in failure of the graft. The patients’ appreciation was measured using an adapted quality of life questionnaire. The results were compared with a similar group who did not undergo reconstruction. The eating of solid food, appearance and speech were considerably better in the reconstructed group. The conclusion is that this means of reconstruction is appropriate for patients with benign but aggressive odontogenic tumours of the mandible, particularly in developing countries, since the expenses seem to be affordable.

Aggressive odontogenic tumours include mainly ameloblastoma and odontogenic myxoma, although there are other rare tumours that could be classified as such. Several studies have shown that the majority of these tumours occur in the mandible. The tumours usually require a marginal or segmental resection with a 1 or 2 cm safe margin into healthy bone. In Tanzania, however, patients present late and commonly have tumours of considerable size that require segmental resections often including half or more of the mandible. Keratocystic odontogenic tumours (KCOTs), previously called odontogenic keratocysts, can also be considered to be aggressive but do not require resection and can be treated by conservative means with good results.

The common denominator of the large aggressive odontogenic tumours, apart from KCOTs, is that they give rise to buccal and lingual swelling and to a certain extent, to soft tissue expansion. Resections, therefore, usually do not lead to major soft tissue deficits, such as seen after resections for malignancies. On the contrary, redundant soft tissue is often present. Thus, when considering immediate reconstruction, the focus has to be mainly on the bony reconstruction since plenty of soft tissue is available.

Reconstruction of these patients in most of the developing countries in Africa, and probably in other areas of the world, implies high costs and, therefore, is often not available. A quality of life (QOL) study on a group of patients who underwent this type of resection without bony reconstruction, revealed rather poor results. These patients will have serious problems with eating and speaking, which affects their social life in a negative way. An affordable and effective means of immediately reconstructing these patients would contribute considerably to their well being. In a previous, preliminary study, the authors reported on the early results of a technique using 2.3 mm titanium plates, autogenous particulate bone grafts and autogenous platelet rich plasma (PRP). Despite some initial problems associated with the plating and radiated bone scaffolds used in the first three cases, the results were encouraging. Similar clinical studies in humans also revealed adequate results. It is the aim of this paper to present the results of a selective but consecutive group of patients who underwent this means of immediate reconstruction.

Materials and methods

From 2003 until 2010, 32 selected but consecutive patients underwent immediate reconstruction of the mandible after ablative surgery for an ameloblastoma. Locations of the ameloblastoma lesions in the mandible of patients who underwent reconstruction are shown in Fig. 1 . Five of these patients have been reported on in the preliminary study on 11 patients from the same institution. The first six patients of that early series of 11 cases were left out in the current study, since problems had occurred because of the use of an erroneous technique.

Fig. 1
Locations of the ameloblastoma lesions in the mandible of patients who underwent reconstruction: (A) in the symphysis (2); (B) in the symphysis and left body of the mandible (7); (C) in the symphysis and right body of the mandible (6); (D) lesions covering the symphysis, right and left body of the mandible body (14); (E) lesions confined to the right body of the mandible (2); (F) lesions confined to the left body of the mandible (1).

The selection was based on several parameters. First, the size of the tumour had to be such that the available plates could bridge the defect, while the tumour warranted a segmental resection. The maximum size of the plates is 173 mm (27 holes) (Smart Shape plates ® , KLS Martin), which implies that the maximum size of the defect to be bridged is 132 mm (21 holes). The resection should also leave a bony segment on both sides to provide sufficient room for the fixation of the plates, using three screws on both sides. Second, the patient had to agree with the suggested treatment, including the harvesting of the graft and had to sign written consent. Third, the condition of the patient had to be sufficient to undergo the proposed treatment. Fourth, the patient had to confirm that he or she would be prepared to return for periodic follow-ups.

All patients underwent a mandibular, segmental resection for an ameloblastoma. In most cases, the periosteum on the lingual and buccal side was left intact. In the cases where the tumour had perforated the bone, that part of the periosteum was resected along with the attached soft tissues. All patients received, 500 mg metronidazole i.v. every 8 h and 1 g ceftriaxone i.v. once a day, 24 h before the surgery and during the subsequent 9 days,. After the ablative surgery, the reconstruction began with harvesting of a cortico-cancellous bone graft from the anterior iliac crest, although this was often done simultaneously by a separate team. The size of this graft was approximately 5 by 5 cm, or more if possible. Additional cancellous bone was harvested from the donor site, in an attempt to harvest as much as possible. In some cases, where the resection was more than 12 cm, grafts had to be taken from both (left and right) iliac crests. The wounds were closed in layers in the usual fashion. Attention was then directed towards the stumps of the remaining mandible which were fixed with two long 2.3 mm titanium plates or pre-shaped plates, when applicable in the proper position with the remaining teeth wired in occlusion. At this stage, the intraoral wounds were closed, using mattress and regular sutures. The wounds were subsequently rinsed with saline before attention was directed to the bone grafts. The harvested bone was particulated and mixed with autogenous PRP and activated with CaCl and thrombin, for which Tissuecol ® was used. This graft was applied between the two titanium plates and the floor of the mouth. Where the periosteum was spared, the graft was placed between the two layers of periosteum, equally divided over the whole length of the defect. It was aimed to achieve a width of at least 8 mm.

The skin was subsequently closed in layers and care was taken to fix the genioglossal and anterior belly of the digastric muscles to the chin muscles, if the symphyseal area was involved in the resection. For this reason a 3 × 0 Mersilene ® suture was led through one or two holes of the lower plate and then tied to the soft tissues of the chin. This was done before the bone graft was applied and would, thus, run through the graft. All patients received a nasogastric tube through which they were fed during the immediate postoperative period for up to 10 days.

The dentate patients were kept in intermaxillary fixation (IMF), using elastics, to help them find their occlusion. These elastics were gradually loosened when the skin and mucosa had healed. Most patients were edentulous or did not have enough teeth left after the resection to allow for IMF.

Patients were seen at regular intervals until it was clear that primary healing had occurred. Follow-up depended on the distance patients had to travel but it was aimed to see them after 3 and 6 months and yearly thereafter. Orthopantomograms were available of each patient pre-and immediately postoperatively and at least after 6 months and at last follow-up.

All patients filled out a QOL questionnaire at the last follow-up. This questionnaire was adapted from the version used in the authors’ preliminary study. In this study, 32 patients who were treated for ameloblastoma without reconstruction during the same period, were compared with the 32 who had primary reconstruction. For the patients with reconstruction a comparison was also made between those who were eventually provided with removable acrylic partial dentures and those who did not have such a denture.

Results

32 patients (11 males and 21 females) with an average age of 27.7 years were included in this study. The follow-up ranged from 6 months to 7 years; the average was 27.9 months. The particulars of the patients are presented in Table 1 . Healing was uneventful in all patients, except three. In one patient a serious infection occurred within 10 days which necessitated continuation of antimicrobial treatment and drainage and rinsing via the submandibular wound. It subsided after protracted use of antimicrobials, resulting in a submandibular fistula that drained pus along with evacuation of some necrotic bone particles. This stopped after about 3 months. The intraoral wound had healed primarily and there was good bony consolidation over the full length of the graft, as seen on radiographs taken 3 months postoperatively. Another patient also developed a submandibular fistula through which some bone particles were expelled. This was treated by irrigation and removal of some necrotic bone chips, which resulted in spontaneous closure of the fistula within 4 months. A third patient had an uncontrollable and severe infection resulting in a total loss of the graft. In three patients, who had undisturbed healing, a prominent upper plate had to be removed before a denture could be made, because it was partially exposed.

Table 1
List and follow up results of ameloblastoma patients who underwent reconstruction from 2001 to 2010.
SN Gender Age (years) Location Size defect (holes in plates) Follow-up (months) Recurrence Complications Time lapse between operation and complication (months) Prosthesis
1 M (EG) 63 Symphysis 11 25 N N N
2 M (SD) 19 Symphysis + left body 17 80 Y Recurrence 80 Y
3 M (JN) 17 Symphysis + left body 14 47 N N N
4 F (SN) 17 Right body 7 63 N N N
5 F (JM) 17 Symphysis + left body 21 83 N N Y
6 F (VEU) 21 Symphysis + left body 31 N N Y
7 F (MMG) 20 Symphysis + left body 16 22 N N N
8 M (SaMo) 23 Symphysis + bodies 12 47 N N Y
9 M (SaMa) 34 Symphysis + right body 19 23 N N Y
10 M (KM) 23 Symphysis + bodies 20 26 N N N
11 M (AM) 55 Symphysis + bodies 17 36 N N N
12 F (DSM) 28 Symphysis + bodies 19 33 N Postop infection Within one week N
13 F (SSM) 27 Symphysis + bodies 17 39 N N N
14 M (SN) 26 Symphysis + bodies 19 24 N N Within one week N
15 F (VA) 30 Symphysis + right body 12 13 N N Y
16 M (MK) 26 Symphysis and bodies 15 36 N N N
17 F (AJ) 22 Symphysis + bodies 18 31 N N Y
18 F (GM) 36 Symphysis + left body 13 13 N N Y
19 F (SMi) 17 Symphysis 11 19 N N Y
20 F (SB) 16 Left body 10 17 N N Y
21 F (BM) 32 Symphysis + bodies 18 16 N N N
22 F (JN) 40 Symphysis + right body 11 23 N N Y
23 F (FM) 17 Symphysis + left body 21 27 N N Y
24 F (CM) 36 Symphysis + right body 14 15 N Post-op infection Within one week N
25 F (VN) 25 Symphysis + right body 14 14 N N N
26 F (SI) 24 Symphysis + bodies 14 13 N N N
27 F (SH) 12 Symphysis + bodies 15 12 N N N
28 F (EM) 20 Symphysis + bodies 19 12 N N Y
29 F (SMa) 34 Symphysis + bodies 16 15 N N N
30 F (KS) 42 Symphysis + bodies 18 14 N N N
31 M (MMa) 35 Symphysis + bodies 18 13 N N N
32 M (Mmo) 31 Symphysis + right body 14 12 N N N
Average 27.6 Average 15.5 Average 27.9 months
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Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Immediate reconstruction of the mandible after resection for aggressive odontogenic tumours: a cohort study
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