A mandibulectomy is a major surgical procedure involving the removal of part or all of the lower jawbone, known as the mandible. This surgery is performed when a disease process has severely compromised the integrity of the jaw, making its removal necessary to prevent further spread or manage structural failure. The mandible is the largest and strongest bone in the face, playing a fundamental role in chewing, speaking, and facial appearance. A mandibulectomy is a complex procedure requiring careful planning to address both the removal of diseased tissue and subsequent reconstruction.
Primary Medical Reasons for Mandibulectomy
The most frequent indication for a mandibulectomy is the treatment of malignant tumors, primarily oral cavity cancers like squamous cell carcinoma, which have invaded or are positioned extremely close to the jawbone. The surgeon must remove the entire tumor along with a margin of healthy tissue to ensure all cancerous cells are eliminated. The proximity of the tumor to the mandible determines whether the bone must be resected along with the soft tissue.
Other medical conditions can also necessitate this surgery. Severe bone infection, known as osteomyelitis, which has not responded to long-term antibiotic therapy, may require the removal of the infected bone section. Osteoradionecrosis, a complication where jawbone tissue dies due to damage from prior radiation therapy, is another cause. Aggressive but non-cancerous tumors or traumatic injuries that compromise the jaw’s structure may also lead to a mandibulectomy.
Categorizing the Types of Mandibular Removal
The extent of the surgery is classified based on how much of the jawbone is removed and whether the remaining bone retains its structural continuity. A marginal mandibulectomy involves removing a portion of the bone without disrupting the main arch of the jaw. This approach is typically used when a tumor is near the bone surface but has not invaded the inner marrow. Preserving the lower border of the mandible helps maintain the jaw’s function and shape, often avoiding the need for extensive bone reconstruction.
A segmental mandibulectomy involves removing a full segment of the jawbone, creating a gap or discontinuity. This more extensive procedure is required when the tumor has fully infiltrated the bone or when the entire thickness of the jaw must be resected to achieve a clear margin. The most radical version is a total mandibulectomy, which entails the complete removal of the entire lower jaw. Both segmental and total resections result in significant functional and aesthetic changes, demanding immediate and complex reconstruction.
Surgical Techniques for Jaw Reconstruction
Reconstruction is an integral step following any segmental or total mandibulectomy to restore the facial skeletal structure. The most common method involves using a vascularized free flap, where tissue, including bone, is transferred from another part of the patient’s body. The fibula free flap, taken from the lower leg, is a widely used option because it provides a long segment of strong bone, along with its own dedicated artery and vein. This bone is then shaped to match the contours of the missing jaw section.
The transferred artery and vein from the flap are connected to blood vessels in the neck using microsurgery, ensuring the new bone segment has a continuous blood supply. This vascularized transfer allows the bone to survive and heal effectively, even in previously irradiated areas. Surgeons may also use other donor sites, such as the scapula (shoulder blade) or the iliac crest (hip), depending on the defect size and location. Alloplastic materials like titanium plates or custom-made prostheses are sometimes used to bridge the gap, often combined with bone grafts or soft tissue flaps.
Adjusting to Post-Surgical Function and Appearance
The rehabilitation phase after a mandibulectomy focuses on regaining function in speech, swallowing, and chewing, which are frequently altered due to the loss of bone and soft tissue. Muscles controlling the tongue, cheeks, and floor of the mouth are attached to the mandible, and their function changes after the surgery. Patients often work with a speech-language pathologist to retrain these muscles, adjusting articulation and managing swallowing difficulties, known as dysphagia.
Swallowing can be particularly challenging, and patients may require a temporary feeding tube for nutrition while their mouth and throat heal. The loss of jaw continuity can cause the remaining mandible to deviate or rotate, affecting the alignment of the upper and lower teeth. Prosthodontics plays a role in long-term rehabilitation by providing dental implants or specialized prostheses that help correct alignment and restore the ability to chew food. The reconstructed jaw may change position over time due to muscle pull and healing.