Ultrasonography for diagnosis and follow-up of carpal tunnel syndrome in mucopolysaccharidosis

Functional results after carpal tunnel release in mucopolysaccharidosis

BACKGROUND

Mucopolysaccharidosis consists of a group of diseases caused by the deficiency of lysosomal enzymes, which may lead to the compression of the median nerve in the carpal tunnel due to the accumulation of glycosaminoglycan, resulting in the hand disability. The study purpose is to present functional results of carpal tunnel release in mucopolysaccharidosis patients. Patients were selected from an enzyme replacement group in the Department of Pediatric Neurology. The legal guardians of the patients were informed about the likely functional change of the hands induced by compression of the median nerve. Clinical evaluation was performed in those patients who received their legal guardians' consent to participate and was included inspection, assessment of functional level, wrinkle test and the digital pinch function to manipulate small and large objects. Ultrasound and electromyography were performed to confirm the clinical median nerve compression. Bilateral extended opening technique was performed to access the carpal tunnel and analyze the anatomic findings of the median nerve and the flexed tendons of the fingers. After the surgical release of the carpal tunnel, the clinical evaluation was repeated. Subjective observations of the legal guardians were also considered.

RESULTS

Seven patients underwent bilateral surgical opening of the carpal tunnel; six boys, mean age of 9.5 (5 to 13), five of them presenting Type II mucopolysaccharidosis, 1 Type I and 1 Type VI. The average follow-up was 12 months (10-13 months). The functional results observed included the improvement in the handling of small and large objects in all children who underwent decompression of the median nerve. The comparison between the pre-operative and post-operative functional levels revealed that 2 patients evolved from Level II to IV, 3 from Level III to IV, 1 from Level IV to V and 1 patient remained in Level III. Tenosynovitis around the flexor tendons and severe compression of the median nerve in the fourteen carpal tunnels were observed during the surgical procedure. In 6 wrists, partial tenosynovitis was performed.

CONCLUSIONS

Despite the improvement in the overall function of the children' hands, we cannot conclude that only surgery was responsible for the benefit. Better designed studies are required.

Ultrasonography Predictive Factors of Response to Local Steroid Injection in Patients with Carpal Tunnel Syndrome

Background:

The aim of this study is to determine the predictive value of ultrasonography for results of local steroid injection in patients with carpal tunnel syndrome (CTS).

Materials and Methods:

This prospective cohort study was conducted during a 1-year period in outpatient clinics of rehabilitation and physical medicine including 35 patients with moderate and severe CTS who receive ultrasonography-guided local steroid injection. The Boston self-assessment questionnaire and electrodiagnosis parameters were recorded at baseline, 1 month, and 3 months after therapy. We also recorded the baseline ultrasonography parameters to determine the predictors of outcome.

Results:

The sensory severity score and functional status scale along with electrodiagnosis parameters decreased significantly at 1 month (P < 0.001) and remained unchanged after 3 months. Volar bulging was negatively associated with sensory nerve action potential latency (r = −0.392; P = 0.020). Cross-sectional area (CSA) of maximal swelling (MS; r = 0.409; P = 0.015), CSA at 2-cm of MS (r = 0.563; P < 0.001), and CSA at 12-cm of MS (r = 0.521; P = 0.001) correlated positively with compound muscle action potential (CMAP) amplitude while maximal swelling/12-cm MS ratio (r = −0.439; P = 0.008) and maximal swelling/2-cm MS ratio (r = −0.342; P = 0.045) correlated negatively. CSA at 12-cm of MS also correlated positively with CMAP amplitude nerve conduction velocity (r = 0.436; P = 0.010).

Conclusion:

Volar bulging, CSA of maximal swelling, CSA of MS at 2-cm, and CSA of MS at 12-cm are among the ultrasonographic predictors of response to local steroid injection in patients with CTS.