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Evaluating Sensory Nerve Outcomes After Horizontal Osteotomy for Mandibular Distraction in Infant Robin Sequence
Nicholas T Do1, Arlen D Denny2, Kristen A Klement2
1Division of Plastic Surgery, Harbor UCLA Medical Center, Torrance, CA.
Insights
The horizontal osteotomy technique for Pierre Robin syndrome is safe for the inferior alveolar nerve. Studies show the mandibular foramen is below the dentoalveolar plane, preserving nerve function long-term.
Area of Science:
- Craniofacial Surgery
- Pediatric Plastic Surgery
- Maxillofacial Surgery
Background:
- The optimal technique for mandibular distraction in infants with Pierre Robin syndrome remains debated.
- Limited data exists on the long-term sensory nerve outcomes following mandibular distraction procedures.
Purpose of the Study:
- To validate the safety of the horizontal osteotomy technique for mandibular distraction in Pierre Robin patients.
- To determine the location of the mandibular foramen relative to the dentoalveolar plane in infants.
- To evaluate the long-term inferior alveolar nerve function in patients who underwent distraction.
Main Methods:
- Analysis of preoperative 3D CT scans from infants (<1 year) with Pierre Robin syndrome to measure mandibular foramen position.
- Bilateral Semmes-Weinstein monofilament testing of the lower lip and chin in patients (>6 years) with a history of early mandibular distraction.
- Inclusion of patients with over 10 years of follow-up for sensory evaluation.
Main Results:
- The mandibular foramen was consistently located below the dentoalveolar plane, averaging 4.7 mm.
- All eight patients in the prospective arm (average age 12.2 years) demonstrated normal sensation in the lower lip and chin.
- Long-term follow-up revealed normative sensation in all evaluated patients.
Conclusions:
- The mandibular foramen's consistent position below the dentoalveolar plane supports the safety of horizontal osteotomy.
- Horizontal corticotomy just above the dentoalveolar plane effectively spares the inferior alveolar nerve in young Pierre Robin patients.
- This technique offers a safe and effective method for mandibular distraction with positive long-term sensory outcomes.
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.
