PURPOSE: Children with Hurler syndrome (HS) develop carpal tunnel syndrome (CTS) owing to glycosaminoglycan deposition secondary to enzyme deficiency. Advancement in the treatment of the underlying enzyme deficiency now commonly includes peritransplant intravenous enzyme replacement therapy (ERT). The primary objective of this study was to determine if the use of limited ERT in addition to hematopoietic stem cell transplantation (HCT) for the treatment of children with HS reduces the incidence of surgical intervention for CTS compared with a cohort of historical controls treated with HCT alone. The secondary objectives were to evaluate the impact of demographic and transplant-related characteristics on the incidence of CTS. Lastly, the results of surgical treatment of CTS in HS are reported.
METHODS: Medical records for a historical group of 43 HS patients who underwent HCT alone (group 1) were compared with 31 HS patients who underwent HCT + ERT (group 2). Both groups were compared for genotype, age at transplant, sex, transplant graft source, median/ulnar nerve conduction study parameters as well as the incidence and treatment of CTS. Pre- and postoperative nerve conduction studies were compared for children treated surgically for CTS.
RESULTS: The cumulative incidence of CTS at 5 years for HS children treated with HCT + ERT was 51% compared with 47% for HS children treated with HCT alone. The incidence of CTS did not depend upon graft source, age at transplant, or sex. Median nerve conduction velocity for both sensory and motor potentials demonstrated significant improvement after carpal tunnel release.
CONCLUSIONS: Although the administration of ERT prior to and for several months after HCT has become routine in our institution, our findings do not suggest this combined therapy is sufficient to decrease the development of CTS. Surgical intervention for median nerve compression remains the treatment of choice for CTS in HS children.
TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.