Functional Leg Length Discrepancy among Pediatric Scoliosis: A Reversible Neuromuscular Compensation from Craniocervical Junction Misalignment

Abstract

Background: Leg length discrepancy (LLD) and pelvic obliquity have often been associated with scoliosis in the literature, and neuromuscular contributions have been mentioned as being possibly involved. It is herein hypothesized that a craniocervical junction (CCJ) misalignment (CCJM) may induce a neuromuscular imbalance leading to functional leg length discrepancy, and that re-establishing a proper alignment can result in some LLD disappearance. Methods: A total of n = 40 consecutive scoliotic children aged 7-16 years, 15-50 Cobb angle, were followed for a mean period of 16 months. Children presenting signs and symptoms of CCJM were evaluated with specific radiographs. Patients for whom the misalignment was confirmed received a CCJ adjustment for their re-alignment. Results: All patients presented at first LLD and CCJM. From a mean LLD of 11.0 mm at first presentation (Pre), there was a mean 90% reduction of LLD at the first follow-up visit (1.1 mm) after the re-alignment (mean 15 days Post), and the mean LLD during the complete follow-up period (2.0 mm) was 82% less than that of the mean Pre-LLD, with a mean yearly 1.2 CCJM recurrences and treatments per patient. Conclusion: The results suggest an association between LLD and CCJM among scoliotic children, and LLD may be reversed by means of a CCJ re-alignment which can be sustained. Occasional CCJM recurrences were typically due to falls or hits. The LLD were measured in a horizontal position. It is likely that in a vertical gravitational position, forcing the feet even on the ground, these neuromuscular imbalance forces responsible for this LLD would not disappear but translate into other pelvic and spinal compensatory deviations that may possibly contribute to the development of scoliosis.