Use of buccal fat pad as a pedicled graft for maxillary reconstruction in a 6-months old with juvenile aggressive ossifying fibroma

Abstract

Juvenile Aggressive Ossifying Fibroma (JAOF) is a benign but locally aggressive fibro-osseous lesion. It is a rapidly growing non-odontogenic neoplasm of the jaws that is often confused with malignant conditions because of its aggressive clinical behaviour. We report a case of maxillary JAOF in a 6-month old child which necessitated partial maxillectomy. The resultant defect was reconstructed with pedicled buccal fat pad. The patient has been followed up for a period of 5 years, with no sign of recurrence.

Highlights

  • Maxillary JAOF results in significant head and neck deformities.

  • Post-resection reconstruction a major challenge in paediatric patients.

  • Buccal fat pad can provide intermediate reconstruction solution.

Introduction

Juvenile Aggressive Ossifying Fibroma (JAOF) is a relatively rare benign non-odontogenic neoplasm of the jaws. The aetiology of JAOF is poorly understood. It generally occurs in children and young adults under 15 years of age in more than 80% of cases [ ]. It is distinguishable from conventional ossifying fibroma on the basis of patient’s age, rapid growth and high recurrence rate [ , ]. Although it is often confused with malignant conditions because of its clinical behaviour, no malignant transformation has however been reported [ ].

This report describes the use of a pedicled buccal fat pad to reconstruct a maxillary defect in a 6 month-old child with JAOF treated by partial maxillectomy.

Case report

A 6-months old female patient presented with a 2-months history of a rapidly growing swelling on her left cheek. She was referred from an Ear Nose and Throat specialist, with an incisional biopsy result suggestive of a fibro-osseous lesion [ ].

On extraoral examination ( Fig. 1 ) 7 a diffuse, painless and firm swelling was noted on the left cheek. Obliteration of the left alar facial groove and flaring of the alar were noted. Her left eye appeared enophthalmic and was superiorly displaced with resultant distension of the left upper eyelid. Intraorally there was a bony hard swelling in the left maxilla, which obliterated the buccal vestibule. The overlying mucosa was normal. CT Scans revealed a well-circumscribed heterogenous lesion in the left maxillary sinus, with displacement of the orbital floor (see Fig. 2 A, B,C).

Fig. 1
Extraoral examination revealed a diffuse swelling on the left cheek. Obliteration of the left alar-facial groove and flaring of the alar were noted.

Fig. 2
CT scans revealed well-circumscribed, heterogenous lesion in the left maxillary sinus, with superior displacement of orbital floor (Arrows) (A: coronal section; B: sagittal section; C: axial section).

The tumour was excised in toto using the Weber Fergusson approach, under general anaesthesia. The defect was filled with buccal fat pad ( Fig. 3 ) 7 : the fat pad was exposed into the defect after excision of the tumour. A curved 1.5mm titanium miniplate was used to reconstruct the left infraorbital rim. A resorbable mesh (Lactosorb, Zimmer Biomet) was secured onto the plate to reconstruct the orbital floor and the zygomatico-maxillary defect. The fat pad was sutured to the mesh and mucosal edges with 4/0 vicryl, making sure that it was under no tension.

Fig. 3
Intra-operative images showing A: the tumour; B: the zygomatico-maxillary defect; C. reconstruction with buccal fat pad. D & E: the titanium plate & Lactosorb with buccal fat pad underneath.

Histopathologic examination of the resected specimen confirmed diagnosis of a benign fibro-osseous lesion most consistent with trabecular juvenile ossifying fibroma. It revealed fibrous connective tissue that exhibited areas that were loose and other zones that were cellular. There was evidence of occasional myxomatous foci with associated areas of pseudocystic degeneration. Areas of haemorrhage and numerous clusters of multinucleated giant cells were present. The mineralised component showed a trabecular pattern with irregular strands of highly cellular osteoid encasing plump and irregular osteocytes. The bone trabeculae were lined by plump osteoblasts with areas of multinucleated osteoclasts ( Fig. 4 ) [ ]. Our patient’s last periodic check-up was at 60-months post-surgery, and she had healed uneventfully ( Fig. 5 ).

Fig. 4
Histology reveals mineralised component showing a trabecular pattern with strands of highly cellular osteoid encasing plump and irregular osteocytes.

Fig. 5
5 years postoperatively: A . clinical photograph. B . coronal CT Scan C . axial CT scan.

Discussion

Management of JAOF tends to be difficult due to their aggressive nature, as well as the high recurrence rate. Surgical resection rather than enucleation and curettage (which have a considerably high recurrence rate) is therefore the preferred treatment of choice [ ]. Surgical treatment however results in major hard and soft tissue defects which impact not only cosmesis and function but craniofacial development as well. Reconstruction of these post-tumour ablative defects poses a big challenge, particularly in children.

The occurrence of tumours such as JAOF in children not only alters craniofacial growth and development but also results in psychological and social disorders [ ]. Treatment planning for these tumours must take into consideration the age of the patient, type and size of the lesion, and reconstruction of the resultant defect. Although treatment is aimed primarily at elimination of the pathology and restoration of both function and aesthetics, it must also consider the potential impact of the treatment and reconstruction on craniofacial growth and development. In this regard, consideration must be given to whether the dissection is going to be sub-periosteal or supra-periosteal; together with the post-ablative grafting options in cases requiring resections. With sub-periosteal dissection, the periosteum is left intact with only the pathological lesion removed, and thus increasing the body’s ability to form new bone especially in children [ , ].

Reconstructive options for jaw defects such as in the present case include vascularised composite free flaps and non-vascularised bone grafts (NVBG). As far as NVBG is concerned, cardinal prerequisites for successful bone grafting include bone transplantation into healthy tissues, a recipient area with adequate blood supply, wide contact between native bone and the graft and rigid fixation [ ]. Iliac crest and rib are the most commonly used NVBGs.

Indications for reconstruction with vascularised bone grafts (VBGs) include inadequate soft tissue bed for grafting (e.g. post radiation), insufficient soft tissue coverage following tumour resection or the need for postoperative radiation therapy [ ]. VBGs thus have the advantage of transferring soft tissues also. Donor sites include radial forearm osteocutaneous flap, iliac crest osteomyocutaneous and fibula osteocutaneous flap. Although fibular and other VBGs have been used for reconstruction of acquired and congenital limb abnormalities [ ], there is little reported on the long-term results on growth, function and cosmetic appearance at both recipient and donor sites in paediatric patients with head and neck defects [ ]. This precluded consideration for vascularised bone graft in the present case. Free flap reconstruction of the paediatric mandible/maxilla requires harvesting from actively growing sites (with its inherent consequences on growth). In addition to concerns about the sizes of the vessels in the flap pedicle and at recipient sites, the other critical consideration in paediatric patients is that the anatomic relationships may be slightly different than those in adults [ ]. A study by Yazar et al. [ ] however reported that paediatric head and neck reconstruction with microvascular free flap transfer is safe and reliable with high survival rate (98.6%). The average age at the time of reconstruction was 11.8 years (range: 2–17 years). Yazar et al. [ ] surmised that despite the small vessel sizes, vascular spasm is less common, presumably due to under-developed muscularis layer in the vessels of children [ ]. This study however fails to give details on the long term follow-up of these patients.

Concern from the parents about possible long-term functional deficits at the donor sites (such as valgus deformities and gait disturbances [ ]), the age of the patient and inadequate bone stock ruled out consideration for use of NVBG/VBG in our patient.

Firstly mentioned by Heister (1783) and later aptly described by Bichat (1802) [ ], the buccal fat pad is purported to perform a number of functions including filling and allowing slippage of fascial spaces between mimetic muscles; enhancement of intermuscular motion, separating muscles of mastication from one another; counteracting the negative pressure during suction in the new born; protection and cushioning of neurovascular bundles from injuries [ ]. Egyedi first reported its use as a pedicle graft for closure of post-surgical maxillary defects in 1977 [ ]. Buccal fat pad (BFP) is described as having a central body and 4 processes (buccal, pterygoid, superficial temporal and deep temporal extensions) ( Fig. 6 ) [ ]. Mean volume of each BFP is about 10.2 ml (range of 7.8–11.2 ml) [ ]. Ease of access has induced interest in its application as a pedicled graft for reconstruction of defects secondary to tumour resection or resultant oro-antral fistula from dentoalveolar surgery or trauma. Advantages include easy harvest, low morbidity, high success rate and elimination of donor-site skin scars. Blood supply to the BFP originates from maxillary artery (buccal and deep temporal branches), superficial temporal artery (transverse facial branch) and facial artery (inferior buccinator artery). The rich vascularity allows a reliable long axial flap and explain the rapid surface re-epithelialisation in a tension-free BFP flap. Re-epithelialisation is thought to start with an initial granulation tissue and subsequent transformation to a parakeratotic stratified squamous epithelium without a lamina propria and submucosa and with an absence of fat cells [ ].

Aug 8, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Use of buccal fat pad as a pedicled graft for maxillary reconstruction in a 6-months old with juvenile aggressive ossifying fibroma
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