O2113: Risk Factors and Outcomes of Neonatal Radial Nerve Palsy

Background: Neonatal radial nerve palsy is a rare, traumatic nerve injury that can occur following prolonged labor. Though previous series have reported high resolution rates, there is limited information regarding the natural history of affected infants. The purpose of this study is to review the presentation, treatment, and objective outcomes of patients with neonatal radial nerve palsy. We hypothesize that neonatal radial nerve palsy is amenable to non-surgical treatment and completely resolves before 1 year of age.

Methods: Patients at a single tertiary-care children’s hospital with a diagnosis of neonatal radial nerve palsy from 2014-2022 were retrospectively reviewed. Demographic information, risk factors, initial presentation, treatment, and serial Active Movement Scale (AMS) scores (range 0-7, 0 = no muscle tone or contraction, 7 = full movement against gravity) were abstracted. Descriptive statistics were used to summarize demographics, risk factors, treatments, and symptoms at presentation while univariate analysis was used to compare AMS scores at presentation and final follow up.

Results: A total of 28 patients (50% female) were identified with a mean age at presentation of 18.0 days. Twenty-four patients had complete wrist and finger drop (Figure 1), while the remaining four had weakness of wrist and finger extension. Mean AMS scores for wrist, finger, and thumb extension at presentation were 2.08/7, 1.58/7, and 1.48/7, respectively. Prolonged labor was recorded for 16 mothers (57.1%) including 12 that underwent Cesarean section and 1 that required an instrumented delivery. Fifteen patients (54%) had skin markings overlying the radial nerve, including posterolateral arm ecchymosis or fat necrosis (Figure 2). Nighttime and naptime wrist/finger extension splinting and stretching were used in 22 patients, stretching alone was utilized in 1 patient, and monitoring alone was recommended in 5 patients. There was a statistically significant increase in mean AMS scores between initial evaluation and final follow up for wrist, thumb, and finger extension (6.72/7, 6.77/7, 6.77/7 respectively, p< 0.001). All 28 patients demonstrated resolution at a mean of 11.8 weeks, with 18/26 demonstrating AMS score normalization by 4 months and 26/26 by 9 months.

Conclusion: This is the largest series of neonatal radial nerve palsy to date with objective and quantitative assessment of the injury’s natural progression over time. Most of the cohort presented with a maternal history of prolonged labor (64%) as well as physical findings consistent with prolonged compression of the radial nerve (54%). While initial presentation can be worrisome for parents and caregivers, excellent outcomes can be expected as demonstrated by all patients reporting complete resolution and AMS score normalization by 1 year of age.