Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence Patients

Abstract

There has yet to be a consensus on the appropriate technique for mandibular distraction in the infant Pierre Robin population nor is their sufficient data on sensory nerve outcomes. The purpose of this study is to validate the safety of the horizontal osteotomy by: (1) determining mandibular foramen location in infant Pierre Robin patients relative to the dentoalveolar plane and (2) evaluate long-term function of the inferior alveolar nerve in previously distracted Pierre Robin patients. Preoperative 3D Computed tomography (CT) scans of Pierre Robin patients < 1 year old were reviewed. A line at the level of the mandibular dentoalveolar plane was drawn across the lingual surface of the ramus and the distance to the mandibular foramen was then measured. Semmes-Weinstein monofilaments of the lower lip and chin bilaterally was performed on mandibular distraction patients in clinic. Inclusion criteria was patients >6 years of age having undergone bilateral mandibular distraction at <1 year of age. Fifteen patients' CT studies were examined. The mandibular foramen was consistently below the level of the dentoalveolar plane at an average distance of 4.7 mm. Eight patients were included in the prospective arm. Average age was 12.2. All patients had normal sensation at 2.83 through all areas. The mandibular foramen reliably exists below the dentoalveolar plane. In addition, all patients reviewed postoperatively with >10 years of follow up demonstrated normative sensation. The horizontal corticotomy performed just above the mandibular dentoalveolar plane spares the inferior alveolar nerve in young Pierre Robin patients undergoing distraction.