Selective Neurectomy and Masseteric-to-Zygomatic Nerve Transfer With Processed Nerve Allograft for Postparalytic Ocular Sequelae: Preliminary Results

Abstract

Oro-ocular synkinesis is a debilitating sequela of facial nerve injury. While selective neurectomy (SN) offers a surgical alternative to botulinum toxin, its efficacy is often limited by recurrence. This study evaluates the feasibility and preliminary results of combining targeted SN with masseteric-to-zygomatic nerve transfer using processed nerve allografts. A retrospective cohort study was conducted on 10 patients (median age, 50.0 y) with postparalytic ocular sequelae who underwent combined SN and nerve transfer during functional gracilis muscle transfer between 2022 and 2024. Preoperative eye function was graded using the Facial Nerve Grading System (FNGS) 2.0. Ocular metrics, including Marginal Reflex Distance 1 and 2, palpebral fissure height, and eye area, were quantified using machine-learning-based software (Emotrics Plus) at rest and during maximal smiling. Median follow-up was 13.0 months. During smiling, the median eye area deviation decreased from 22.13 mm² (IQR: -16.81 to 44.78 mm²) to 4.28 mm² (IQR: -21.64 to 12.33 mm²). Patients with an initial FNGS eye score of 2 demonstrated a median reduction in absolute eye area deviation of 8.89 mm², while those with scores of 3 to 5 showed a reduction of 1.81 mm². Static lower eyelid position (MRD2) remained stable postoperatively (median deviation: -0.41 mm to -0.31 mm). This combined approach is technically viable and introduces the potential for neurological occupancy to address the limitations of conventional neurectomy. Preliminary findings suggest that the procedure provides functional release of synkinetic contractures while maintaining lower eyelid stability, particularly in patients with predominant synkinetic symptoms.