Assessment of facial nerve injury with “House and Brackmann facial nerve grading system” in patients of temporomandibular joint ankylosis operated using deep subfascial approach

BACKGROUND: Preservation of the functional integrity of the facial nerve (FN) is a critical measure of success in temporomandibular joint (TMJ) surgery. In spite of the development of a myriad of surgical approaches to the TMJ, FN remains at risk. The deep subfascial approach provides an additional layer of protection (the deep layer of the temporalis fascia and the superficial temporal fat pad) to the temporal and zygomatic branches of the FN and thus, is the safest method to avoid FN injury. OBJECTIVES: To assess FN injury following TMJ surgery using deep subfascial approach and measuring it on House and Brackman facial nerve grading system (HBFNGS). MATERIALS AND METHODS: Twenty TMJs in 18 patients were operated for TMJ ankylosis, using “the deep subfascial approach.” FN function was assessed postoperatively at 24 h, 1 week, 1 month, 3 months, 6 months using HBFNGS. Statistical analysis was done using SPSS 16.0. RESULTS: Of 20 surgical sites 3 sites showed Grade III (moderate) FN injury and 17 sites showed Grade II (mild) FN injury at 24 h. The condition improved with time with full recovery of FN at all surgical sites at 6 months. CONCLUSION: The deep subfascial approach has a distinct advantage over the conventional approaches when dissecting the temporal region and is the safest method to avoid injury to FN.