Key Anatomical Clarifications for the Marginal Mandibular Branch of the Facial Nerve: Clinical Significance for the Plastic Surgeon

Background The marginal mandibular branch (MMBr) of the facial nerve is the least likely to recover from injury due to infrequent anastomosis with other branches. The MMBr has been described as coursing superior to the inferior border of the mandible. However, studies have reported variations in its location in embalmed and fresh specimens. It’s been postulated that the embalming process may effect its anatomical position. Objective Re-evalulate the location of the MMBr relavtive to the inferior border of the mandible in both fresh and embalmed cadavers, and compare its poition with sex, side of the face, and age. Methods Superficial fascial planes were dissected to reveal the MMBr and its anatomical relationships. Distance between the most inferior branch of the MMBr and antegonial notch were measured bilaterally. The most inferior position of the MMBr between the antegonial notch and gonion was measured. Fresh heads were used as a comparison, with an additional measurement taken between the MMBr and gonial angle. Results The MMBr was located inferior to the border of the mandible (90.3%) more often than above (9.6%). No significant differences were found between fresh and embalmed cadavers, sex, side of body, or age (p > .05). No significant difference was found between intact cadavers and fresh heads (p > .05). Conclusions This study confirms and describes reliable landmarks for safety zones for the MMBr during plastic and reconstructive surgery of the lower face and upper neck. This data adds reliability to studies using embalmed cadavers to investigate nerve locations.

Iatrogenic injury and regeneration of the facial nerve after parotid gland tumour surgery: a pilot study with clinical and neurophysiological assessment

Introduction. Benign tumour surgery of the parotid gland may cause iatrogenic injury of the facial nerve, with results of postoperative treatment depending on the type of injury. The study aimed to clarify the mechanism of facial nerve injury after benign tumour surgery of parotid gland. Materials and Methods. The effectiveness was verified preoperatively and 1, 3, 6 and 17 months postoperatively. House-Brackmann scales, electroneurography, blink reflex study and needle electromyography were performed. Pharmacological treatment (Galantamine, Cocarboxylase, Dexamethasone, Triamcinolone) and supervised physiotherapeutic procedures (Facial-Oral-Tract-Therapy, Proprioceptive neuromuscular facilitation) were applied for six months. Results. Tumour removal led to the total paralysis of the left facial nerve, IV, III and III House-Brackmann grades were ascertained at the subsequent 3rd–5th periods of observation. In postoperative studies, electroneurography results showed full functional recovery of the frontal branch and incomplete regeneration in the marginal mandibular branch. Blink reflex examination showed proper parameters of evoked potentials only during preoperative and the last observation period. Residual voluntary activity of the frontal muscle and weak voluntary activity of orbicularis oris muscle were recorded in the needle electromyography examination. Contracture of mimic muscles at rest and improvement of their voluntary activity on the left side was observed six months after surgery compared to the early period of observation. Conclusion. Consecutive studies showed the predominant axonal type of injury in the marginal mandibular branch and neuropraxia effect of the facial nerve, allowing the creation of a rehabilitation programme optimal for the functional recovery of the nerve.

Total temporomandibular joint replacement without a submandibular incision

Temporomandibular joint replacement is a well-accepted and successful treatment option for advanced pathology of the temporomandibular joint. There are however a number of complications associated with the procedure such as post-operative infection, facial nerve damage and scarring. Total joint replacement has traditionally involved the use of both a pre-auricular and submandibular incision. We present an approach that uses only a pre-auricular incision without the need for a submandibular incision. This approach is less invasive and has the potential to decrease risk of damage to the marginal mandibular branch of facial nerve and scarring of the neck.