Soft Tissue Coverage with Submental Flap in Massive Medication-Related Osteonecrosis of the Mandible

Reza Tabrizi, Mehrdad Dehghanpour Barouj, Parsa Behnia and Pedram Bakhshaei^*
*Correspondence: Pedram Bakhshaei, Department of Oral and Maxillofacial Surgery, Dental School, Shahid Beheshti University of Medical Sciences, Iran, Email:

Keywords

Bisphosphonate associated osteonecrosis of the jaw • Mandible • Osteonecrosis • Myocutaneous flap

Introduction

Intravenous Bisphosphonates (BPs) are used to treat cancer-related conditions, including hypercalcemia of malignancy, Skeletal-Related Events (SREs) associated with bone, and for management of lytic lesions in the setting of multiple myeloma [1]. Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ) is a serious complication of BPs, which affects patients' quality of life. The American Association of Oral and Maxillofacial Surgeons (AAOMS) modified the nomenclature of BRONJ into medication-related osteonecrosis of the jaw (MRONJ) in 2014, to cover the growing number of osteonecrosis cases involving the jaw associated with antiangiogenetic therapies and other antiresorptive (denosumab) [2]. It was suggested that soft tissue coverage is essential for the proper treatment of MRONJ [3]. Direct toxic effect of BPs on oral mucosa causes a breakdown or impaired healing of the natural barrier of mucosa [4]. In this article, a massive case of MRONJ of the mandible was described which soft tissue was restored with a submental flap.

Case Report

A 63-year-old female presented to the oral and maxillofacial surgery department of Shahid Beheshti University of Medical Sciences on September 1, 2017. She was a known case of multiple myeloma. She underwent chemotherapy (Bortezomib 1.3 mg/m³, Doxorubicin 9 mg/m³, and Dexamethasone 40 mg) daily in 2014. Also, She received five treatment courses of Zometa (Zoledronic acid) 4 mg intravenously over a minimum of 15 minutes in 4 weeks intervals in 2015. She had a history of nonsurgical (without flapping) teeth removal in 2016. After teeth extractions, she had a massive exposed bone area in the mandible with pain (Figures 1 and 2). Initially, an incisional biopsy was conducted to rule out bone metastasis. Histological examination demonstrated bone necrosis without any malignancy invasion. Clinical examination showed stage II MRONJ.

Surgical technique

The patient underwent extensive debridement with removing necrotic bone to reach the perfused (bleeding) bone. To cover extensive exposed bone area, a submental flap was used. Doppler mapping was applied to identify the facial and submental arteries preoperatively. An elliptical skin paddle was marked based on the size of the defect. First, the ipsilateral lower border was incised, and the submandibular gland exposed. The upper border of the gland was skirted around to identify the submental and facial vessels. The ipsilateral anterior belly of the digastric was included in the flap. Next, the contralateral side of the flap was elevated as far as the midline in the subplatysmal plane. The skin incision in the upper margin of the flap was made 2 cm below the body of the mandible (Figure 3). The flap was rotated superiorly at the lateral of the mandible into the oral cavity and covered the extensive exposed area (Figure 4). In 1 year follow up, there was no sign of exposing bone, pain, or pus. Donor site healing was excellent, and the scar was well hidden.

Discussion

Debridement is a minimally invasive surgical procedure, which is mainly performed to manage stage II disease. This stage is characterized by exposed or necrotic bone with associated pain and soft tissue inflammation. Debridement can also be performed when there are thin sharp bone spicules [5]. Free bleeding edges in surgical intervention do not guarantee any relapse of the primary lesion. Therefore, a surgical intervention aimed at removing the infected tissue may instead result in wider bone exposure and exacerbate the symptoms [6]. The success of surgical intervention has been reported to be 59% to 90% [7]. After complete debridement of necrotic bone, a watertight defect closure is needed to minimize the risk of microbial contamination of the exposed bone. Soft tissue coverage of bone defect plays an important role in the success of treatments [8]. Furthermore, these patients may be immunosuppressed, which leads to having prolonged and complicated healing. The mylohyoid flap was used to cover the bone defect in BRONJ and reduced the relapse of the treatment [9,10]. The size of the mylohyoid flap limited use of it in extensive bone defects.

References

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