An Anatomical study for localisation of Zygomatic branch of Facial nerve and Masseteric nerve - An aid to nerve coaptation for facial reanimation surgery: A cadaver based study in Eastern India.

CONTEXT: In cases of chronic facial palsy, where direct neurotisation is possible, ipsilateral masseteric nerve is a very suitable motor donor. We have tried to specifically locate the masseteric nerve for this purpose.

AIMS: Describing an approach of localisation and exposure of both the zygomatic branch of Facial nerve and the nerve to masseter, with respect to a soft tissue reference point over face.

SETTINGS AND DESIGN: Observational cross sectional study, conducted on 12 fresh cadavers.

SUBJECTS AND METHODS: A curved incision was given, passing about 0.5cms in front of the tragal cartilage. A reference point "R" was pointed out. The zygomatic branch of facial nerve and masseteric nerve were dissected out and their specific locations were recorded from fixed reference points with help of copper wire and slide callipers.

STATISTICAL ANALYSIS USED: Central Tendency measurements and Unpaired "t" test.

RESULTS: Zygomatic branch of the Facial nerve was located within a small circular area of radius 1 cm, the centre of which lies at a distance of 1.1 cms (±0.4cm) in males and 0.2cm (±0.1cm) in females from the point, 'R', in a vertical (coronal) plane. The nerve to masseter was noted to lie within a circular area of 1 cm radius, the centre of which was at a distance of 2.5cms (±0.4cm) and 1.7cms (±0.2cm) from R, in male and female cadavers, respectively. Finally, Masseteric nerve's depth, from the masseteric surface was found to be 1cm (±0.1cm; male) and 0.8cm (±0.1cm; female).

CONCLUSIONS: This novel approach can reduce the post operative cosmetic morbidity and per-operative complications of facial reanimation surgery.