Novel loop neurorrhaphy technique to preserve lower lip sensate in mandibular reconstruction using an innervated vascularized iliac bone flap.

Abstract

This study aimed to introduce a novel loop neurorrhaphy technique using an innervated vascularized iliac bone flap (VIBF) with vascularized ilioinguinal nerve (IIN) to reconstruct the inferior alveolar nerve (IAN) and preserve lower lip sensation simultaneously with mandibular reconstruction. This study prospectively included patients who underwent mandibular reconstruction using VIBF from May 2018 to April 2020. Subjects were allocated into two groups: (1) Group I; innervated VIBF with loop neurorrhaphy (IIN doubly anastomosed with IAN and mental nerve), (2) Group II (control); conventional VIBF. Evaluation was done with operative time, intraoperative indocyanine green (ICG), lower lip sensory assessment (two-point discrimination [TPD] test and current perception threshold [CPT]), and drooling. Twelve patients were included; 6 in each group, (7 males and 5 females), age ranging from 18 to 57 years (average: 36.75 years). In all cases, intraoperative perfusion of IIN was confirmed by ICG. Group I showed a statistically significant more flap harvesting time compared with group II (mean difference, 5.67 min; P= 0.0091). There was a significant difference in sensory recovery favoring group I (P< 0.05). The TPD results in group I showed an average of 9.8± 6.9 mm and 6.2± 5.7 mm on operated and non-operated sides, while Group II showed a poor sensory recovery, and the TPD showed an average of 24.6± 6.7 mm and 8.4± 2.3 mm on operated and non-operated sides. The CPT results showed a significant difference between both groups. In Group I, the extent of drooling was 3.16 ± 0.75, while in Group II, the score was 1.6± 0.81, revealing a significant difference favoring Group I. Concurrent mandibular reconstruction using VIBF and loop neurorrhaphy with vascularized IIN to reconstruct IAN successfully restore lower jaw form and preserve lip sensation.