Limb lengthening in children with Russell-Silver syndrome: a comparison to other etiologies.

INTRODUCTION/BACKGROUND Russell-Silver syndrome (RSS) is the combination of intrauterine growth retardation, difficulty feeding, and postnatal growth retardation. Leg length discrepancy (LLD) is one of four major diagnostic criteria of RSS and is present in most cases. We aimed to ascertain whether pediatric RSS patients will adequately consolidate bony regenerate following leg lengthening. MATERIALS AND METHODS We retrospectively reviewed pediatric RSS patients who underwent limb lengthening and compared them to a similar group of patients with LLD resulting from tumor, trauma, or congenital etiology. The primary outcome measurement was the bone healing index (BHI). RESULTS The RSS group included seven lengthened segments in five patients; the comparison group included 21 segments in 19 patients. The groups had similar lengthening amounts (3.3 vs. 3.9 cm, p = 0.507). The RSS group healed significantly faster (lower BHI) than the control group (BHI 29 vs. 43 days/cm, p = 0.028). Secondary analysis showed no difference between RSS and trauma patients in terms of the BHI (29 vs. 31); however, the BHI of the RSS group was significantly lower than both of the other congenital etiologies (29 vs. 41, p = 0.032) and tumor patients (29 vs. 66, p = 0.019). The RSS patients had fewer and less significant complications than the controls. DISCUSSION The limb lengthening regenerate healing of RSS patients is faster than the healing of patients with other congenital etiologies and tumor patients, and is as fast as the regenerate healing of patients with posttraumatic LLD. Although all RSS patients were treated with human growth hormone (hGH), we are unable to isolate the hGH contribution to the regenerate bone healing. We conclude that RSS patients can have safe limb lengthening.