Wide Surgical Excision with Split Rib Graft Reconstruction of Mandible for Ameloblastoma; Our 10 Year Experience

Abstract

Ameloblastoma or adamantinoma is a benign odontogenic tumour arising in facial bones mostly in mandible. There are different modalities of treatment for ameloblastoma viz. chemotherapy, radiation therapy, curettage and liquid nitrogen but surgical resection or enucleation remains the most definitive treatment for this condition. After surgical excision mandibular defect can be reconstructed by non vascularised bone graft or free tissue transfer. we are presenting a detailed study of 50 patients in which mandible was reconstructed with non vascularised split rib graft after surgical resection of ameloblastoma. This is easy, less time consuming and requires no expertise with excellent results.

Background

The mandibular ameloblastoma is a benign odontogenic tumor that develops from the remaining components of the enamel organ (Epithelial rests of Mallasez), originally described by Falkson in 1879. Later on Mallasez introduced the term “adamantinoma” and “Churchill [1]” finally named it in 1934 as ameloblastoma. Ameloblastoma is responsible for 1 % of all the oral and maxillomandibular cysts and tumors [2]. These tumors are benign in nature, progress slowly; the resulting lesions can cause severe abnormalities of the face and jaw. Additionally, because abnormal cell growth easily infiltrates and destroys surrounding bony tissues, wide surgical excision is required to treat this disorder. And it has a high percentage of local recurrence rate and possible malignant development when treated inadequately.

There are three different macroscopic subtypes: solid or multicystic, unicystic and peripheral. With the advancement of craniofacial surgical techniques, use of free flaps for mandibular reconstruction; the segmental mandibulectomy and immediate reconstruction with free flaps are beginning to be used more effectively for the treatment of the mandibular ameloblastoma. But centres where microvascular surgery facilities are not available, non vascularised cancellous bone graft remains option of choice either from iliac creast or rib. There is a role of non vascularized bone graft if there is little the adjacent bone fragment. The technique is easy and less time consuming and can be done in places where facility of free tissue transfer does not exists.

Aim

The aim of this article is to evaluate the clinical results of the patients with mandibular ameloblastoma who were treated with segmental mandibulectomy and immediate reconstruction with non vascularised split rib graft.

Materials and Methods

Study was conducted in department of plastic & reconstructive surgery, in J.N.Medical College, A.M.U. Aligarh, India; since February 2002–February 2012. Total 50 patients with ameloblastoma mandible were treated with wide surgical excision and immediate reconstruction with non vascularised split rib graft. Patients age distribution is provided in Table 1. Females predominated with female to male ratio of 31:19. follow up period ranged from 2 month to 10 years.

Table 1.

Age of presentation

Age (years)	No. of patients	Percentage
11–25	17	34
26–40	25	50
41–55	8	16

All the patients were evaluated pre-operatively; clinically and radiologically. All the cases were subjected to midline lip splitting incision and defect closed with free rib graft from ipsilatreral side. In females the incision was placed in inframammary crease. The involved part of the mandible was explored and the lesion was removed enblock and send for histopathological examination which was consistent with ameloblastoma.

A healthy margin of 1 cm was removed on either side and cortex was tunneled on either Side. The created defect was assessed and template was made. Rib along with periosteum was harvested from ipsilateral Chest. The rib was splited longitudinally. The two halves were overlapped Sharing 1/3 of the Width. Then two halves were fixed together with stainless steel wire no 24. The rib graft was then telescoped in mandible and fixed with screws.

Incision was closed over suction drain of size F.G. 10 in every case and nasogastric tube feeding was started in evening on the day of operation. From post op day 2; respirometery in form of chest physiotherapy was started. Suction drain were removed after 2 days.

Results

Results were assessed in grade as given below: in Table 2.

Table 2.

The results

Grade	No. of cases	Percentage
Grade 1	30	60
Grade 2	15	30
Grade 3	04	08
Grade 4	01	02

Grade 1: Excellent, good symmetry in shape and position.

Grade 2: Good, natural look and some charm of normal mandible.

Grade 3: Fair, problems with shape.

Grade 4: Poor, graft loss.

Pleural puncture, local infection and graft loss were major complication, given in Table 3.

Table 3.

Complications

Type	No. of cases	Percentage
Pleural puncture	04	08
Infection	02	04
Graft loss	01	02

Discussion

Ameloblastoma is the most common epithelial odontogenic tumor. It usually occur in individuals aged 20–40 years. wide surgical excision had been advocated for its management to prevent its recurrence. more than 1 cm of normal margin of mandible and overlying periosteum if cortical perforarion had occurred has to be excised [3–11]. More conservative treatment modalities such as curettage, cryotherapy, or enucleation have resulted in recurrence rates of 75–90 % [4, 5]. Therefore we removed 1 cm normal margine in all case.

Regarding reconstruction after the excision free tissue transfer is the best option in terms of form,function and aesthetic appearance by Chana [12] and Disa [13]. But when micro vascular expertise is lacking; non vascularised bone graft is the option of choice.

In all our 50 cases reconstruction was done by non vascularised split rib graft. Despite the large tumors in our patient population, recurrences were not observed in patients undergoing mandibular resection 90 % patient has good to excellent result in terms of shape, symmetry, function and aesthetic appearance. Complications viz. pleural puncture was identified intra operatively and were repaired and prophylactic ICTD was done in one patient, infection was treated conservatively with antibiotics coverage as per pus culture report. Fig. 1, 2, 3, 4, 5, 6, 7, 8, 9.

Fig. 1.

Pre-op photograph showing right sided ameloblastoma mandible of patient 1

Fig. 2.

Orthopantomogram (OPG) of same patient 1

Fig. 3.

Intra-op photograph of tumor of same patient 1

Fig. 4.

Intra op photograph after split rib graft reconstruction of manbibular defect

Fig. 5.

Post-op photograph of same patient 1

Fig. 6.

Post-op orthopantomograme of same patient 1

Fig. 7.

Pre-op photograph of patient 2

Fig. 8.

Post-op photograph of patient 2

Fig. 9.

Post-op ortopantomograme of patient 2

Conclusion

There are various techniques for mandibular reconstruction after resection of ameloblastoma even for larger defect rib graft is ideal. The split rib graft technique can be done at centers where micro vascular Surgery is not routine. This is easy, less time consuming and requires no expertise with excellent results in form of shape, symmetry, function and aesthetic appearance.