Intraoperative facial nerve monitoring during mandibular distraction osteogenesis in infants with Robin sequence
Monica Manrique*, Esperanza Mantilla-Rivas, Juan Rojas-Cortez, Md Sohel Rana, Sara Toro-Tobon, John Thomas, Gary F. Rogers, Albert Oh
Plastic and Reconstructive Surgery, Children's National Hospital, Washington,
Mandibular distraction osteogenesis (MDO) is used to treat severe upper airway obstruction in infants with Robin Sequence (RS). While MDO is effective, complications are not uncommon, including facial nerve dysfunction (FND), particularly involving the marginal mandibular nerve (MMN). We aim to evaluate changes in nerve conduction during MDO procedures and analyze if these changes are associated with clinical findings of FND.
We monitored facial nerve conduction in infants with RS undergoing MDO from 2019 to 2022 in our tertiary care institution, using electroneuronography (ENoG). This technique involves electrical stimulation of the facial nerve (FN) near the stylomastoid foramen and subsequent measurement of the motoric response, recorded at the orbicularis oculi and mentalis muscles. ENoG data was recorded at 10 different surgical points from skin incision to closure. Changes in latency and amplitude were compared to baseline measurements. Any increase in latency ≥10% or decrease in amplitude ≥60% from the baseline was considered a significant change in nerve conduction.
Seven bilateral surgical procedures [osteotomy/placement of hardware (4); hardware removal (2); hardware replacement (1)] out of 24 patients were randomly chosen and analyzed, for a total of 14 unilateral investigations. Mean age at surgery was 20.8 months. Retraction during osteotomy was the surgical step most associated with changes in MMN conduction, with a significant decrease in amplitude or increase in latency noted in 35.7% and 14.3%, respectively. Temporary MMN dysfunction was observed in 4 postoperative clinical examinations (28.6%). Sensitivity/Specificity were 50%/50%, while PPV/NPV were 20%/80%.
Intraoperative injury to the MMN may occur during MDO procedures, particularly during retraction/osteotomy. Real-time facial nerve intraoperative monitoring may be a useful tool that protects the MMN. Of note, no patient in our ongoing studies has demonstrated long-term FND >6 months, since initiation of this protocol.
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