Carpal tunnel syndrome in lysosomal storage disorders: simple decompression or external neurolysis?

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.

Analysis of the Long-Term Outcome in Open Carpal Tunnel Release Surgeries with and without External Neurolysis of Median Nerve, Using Boston Carpal Tunnel Questionnaire (BCTQ)-Hindi Version

Background  The effectiveness of open carpal tunnel release (OCTR) in treating carpal tunnel syndrome (CTS) is well known. However, the role of ancillary external neurolysis of the median nerve is not well-documented. The Boston carpal tunnel questionnaire (BCTQ) is a commonly used disease-specific outcome instrument for CTS, which is validated across major languages of the world. No such validated Hindi version of BCTQ exists.

Objectives  To analyze and compare the long-term outcome in patients who underwent OCTR alone and OCTR with external neurolysis of the median nerve, using BCTQ–Hindi version, while checking its validity.

Materials and Methods  A retrospective, cross-sectional study was conducted at a tertiary care institute. The BCTQ was translated into Hindi language by a language expert. Eighty-four consecutive patients who underwent either unilateral/bilateral OCTR, with or without external neurolysis of the median nerve, between 2009 and 2019 were included in the study. Outcome analysis was done using BCTQ–Hindi version and patient satisfaction scoring. BCTQ–Hindi version was examined for statistical validity. Subgroup analysis of the outcome based on surgical technique (OCTR vs. OCTR with external neurolysis) used was carried out.

Results  Response rate was 80.9%. Total hands evaluated were 108. BCTQ–Hindi version showed statistical validity. Overall symptom severity score (SSS) and functional severity score (FSS) were 1.14 ± 0.4 and 1.12 ± 0.35, respectively. Subgroup analysis of outcome revealed statistically significant results in favor of OCTR with external neurolysis of the median nerve.

Conclusions  BCTQ–Hindi version is statistically validated. OCTR with external neurolysis of the median nerve is a promising avenue in surgical management of CTS. Further prospective studies are warranted.

Peripheral Nerve Compression Syndromes in Children

Nontraumatic neuropathies of the upper limb are rare in children. In this paper, we present the latest updates in this field and also critically review the diagnosis and treatment of nerve compression syndromes in children. This review describes the most common manifestations including idiopathic carpal tunnel syndrome (CTS), CTS occurring as a component of lysosomal storage diseases (mucopolysaccharidosis) and hereditary neuropathies, ulnar nerve neuropathy, and atraumatic radial nerve neuropathies.

The mucopolysaccharidoses: advances in medical care lead to challenges in orthopaedic surgical care

The mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders with clinical manifestations relevant to the orthopaedic surgeon. Our aim was to review the recent advances in their management and the implications for surgical practice. The current literature about MPSs is summarised, emphasising orthopaedic complications and their management. Recent advances in the diagnosis and management of MPSs include the recognition of slowly progressive, late presenting subtypes, developments in life-prolonging systemic treatment and potentially new indications for surgical treatment. The outcomes of surgery in these patients are not yet validated and some procedures have a high rate of complications which differ from those in patients who do not have a MPS. The diagnosis of a MPS should be considered in adolescents or young adults with a previously unrecognised dysplasia of the hip. Surgeons treating patients with a MPS should report their experience and studies should include the assessment of function and quality of life to guide treatment. Cite this article: Bone Joint J 2017;99-B:1132-9.

Does orthopaedic surgery improve quality of life and function in patients with mucopolysaccharidoses?

PURPOSE

Mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders associated with involvement of multiple organs along with a generalised skeletal dysplasia. Both haematopoetic stem cell transplant and enzyme replacement therapy have improved the outlook for patients while surgery remains high-risk and there is little information on clinical or functional outcome to justify many of the surgical procedures performed. This paper aims to summarise the orthopaedic surgical procedures in MPS patients for which quality of life (QoL) and functional data are available and to describe additional QoL and functional measurement tools of relevance to the assessment of orthopaedic outcomes in MPS.

METHODS

We reviewed the available literature to look for reported outcomes of orthopaedic surgery to lower and upper limbs and the spine. In addition, we describe the general and MPS-specific health measures that might be of relevance to the orthopaedic surgeon.

RESULTS

There is some evidence in the literature that orthopaedic surgery may improve QoL and function in some specific aspects of the MPS condition (in relation to genu valgum, carpal tunnel syndrome and trigger digits); however, the literature is sparse and consists of level 4/5 studies only. Further studies of these conditions should include QoL and functional assessment in order to confirm or refute these reports. In other areas (spine and hip), outcomes are judged largely on radiographic appearances with little clinical correlation and short follow-up; however, one long-term study of function following hip dysplasia surgery suggests poor outcomes. Anaesthetic morbidity/mortality is not insignificant in these complex patients with multi-organ involvement. Careful assessment is required, particularly when there is neurological involvement.

CONCLUSIONS

Orthopaedic surgeons involved with MPS patients should be encouraged to use and report measures of QoL and function with respect to musculoskeletal manifestations and response to surgery, recognising that such assessments in these complex and challenging patients may require a multidisciplinary approach.

Lysosomal storage disorders: A review of the musculoskeletal features

The lysosomal storage disorders are a collection of progressive, multisystem disorders that frequently present in childhood. Their timely diagnosis is paramount as they are becoming increasingly treatable. Musculoskeletal manifestations often occur early in the disease course, hence are useful as diagnostics clues. Non-inflammatory joint stiffness or pain, carpal tunnel syndrome, trigger fingers, unexplained pain crises and short stature should all prompt consideration of a lysosomal storage disorder. Recurrent ENT infections, hepatosplenomegaly, recurrent hernias and visual/hearing impairment - especially when clustered together - are important extra-skeletal features. As diagnostic and therapeutic options continue to evolve, children with lysosomal storage disorders and their families are facing more sophisticated options for screening and treatment. The aim of this article is to highlight the paediatric presentations of lysosomal storage disorders, with an emphasis on the musculoskeletal features.

Epidemiology and diagnosis of lysosomal storage disorders; challenges of screening

The lysosomal storage disorders (LSDs) are a group of genetic disorders resulting from defective lysosomal metabolism and subsequent accumulation of substrates. Patients present with a large phenotypic spectrum of disease manifestations that are generally not specific for LSDs, leading to considerable diagnostic delay and missed cases. Introduction of new disease modifying therapies for LSDs has made early diagnosis a priority. Increased awareness, but particularly the introduction of screening programs allow for early diagnosis and timely initiation of treatment. This review will provide insight into the epidemiology and diagnostic process for LSDs. In addition, challenges for carrier screening, high-risk screening and newborn population screening for LSDs are discussed.

Carpal tunnel syndrome in fabry disease

Carpal tunnel syndrome (CTS) is a common peripheral mononeuropathy affecting up to 4% of the general population, typically women in late middle age. The incidence in patients with Fabry disease (FD) is unclear, but may affect 25% of patients with this X-linked lysosomal storage disease. We report three cases of CTS in young Caucasian male patients with classical FD, who developed CTS symptoms with supportive nerve conduction study (NCS) findings. Two patients had bilateral CTS and two had evidence of concurrent ulnar nerve neuropathy on NCS, suggesting a systemic process contributed to nerve compression. All were receiving enzyme replacement therapy (ERT) and had a moderate burden of FD complications. It is possible that an increase in connective tissue in the intracarpal canal in FD patients may be incited by injury to fibroblasts, via either accumulation of globotriaosylceramide (GL3) or local ischaemia through endothelial injury. The former hypothesis may be a more plausible explanation for the development of CTS, as histology of the flexor retinaculae from our patients has demonstrated fibroblasts with characteristic vacuolation and excessive myxomatous stroma, despite endothelial clearance of GL3 in these patients receiving ERT. CTS should not be overlooked in FD patients and young patients presenting with CTS should be evaluated for an underlying systemic or genetic disorder. Surgical carpal tunnel decompression was effective in our patients, already troubled by long-standing acroparesthesia, in providing sustained relief of symptoms.