Surgical treatment of carpal tunnel syndrome and trigger digits in children with mucopolysaccharide storage disorders

Mucopolysaccharidosis: What Pediatric Rheumatologists and Orthopedics Need to Know

Mucopolysaccharidosis (MPS) is a group of disorders caused by the reduced or absent activity of enzymes involved in the glycosaminoglycans (GAGs) degradation; the consequence is the progressive accumulation of the substrate (dermatan, heparan, keratan or chondroitin sulfate) in the lysosomes of cells belonging to several tissues. The rarity, the broad spectrum of manifestations, the lack of strict genotype-phenotype association, and the progressive nature of MPS make diagnosing this group of conditions challenging. Musculoskeletal involvement represents a common and prominent feature of MPS. Joint and bone abnormalities might be the main clue for diagnosing MPS, especially in attenuated phenotypes; therefore, it is essential to increase the awareness of these conditions among the pediatric rheumatology and orthopedic communities since early diagnosis and treatment are crucial to reduce the disease burden of these patients. Nowadays, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are available for some MPS types. We describe the musculoskeletal characteristics of MPS patients through a literature review of MPS cases misdiagnosed as having rheumatologic or orthopedic conditions.

Carpal tunnel syndrome and finger deformities in children with mucopolysaccharidoses and mucolipidoses: a retrospective review of 52 patients

This single-centre retrospective study reports our management of carpal tunnel syndrome in 52 children (103 hands) with mucopolysaccharidoses and mucolipidoses. All except one were bilateral. The median age at surgery was 4 years (range 1.5 to 12). The diagnosis of carpal tunnel syndrome was confirmed by an electromyogram (EMG) in all patients; 38% of these presented without any clinical signs. Surgical neurolysis was performed in all hands, combined with epineurotomy in 52 hands (50%) and flexor tenosynovectomy in 75 hands (73%). Surgery was bilateral in 98% of children (102 hands). The mean follow-up was 12 years (range 1 to 19) and the EMG was normalized in 78% of hands. Ten patients suffered recurrence, eight of whom required further surgery. Screening for carpal tunnel syndrome is essential for the management of children mucopolysaccharidoses and mucolipidoses. Surgical treatment should be carried out early with follow-up by EMG to detect recurrence.Level of evidence: IV.

Pediatric Trigger Digits

Pediatric trigger thumb (PTT) and finger (PTF) are upper extremity deformities that frequently go unrecognized by providers. Early recognition by pediatricians and caregivers is vital because PTT is successfully treated nonoperatively in more than 95% of patients if diagnosed early. Similarly, PTF can be successfully treated nonoperatively in 67% of patients. Although PTT is typically benign and 10 times more common, PTF may be associated with underlying concurrent medical conditions, such as juvenile rheumatoid arthritis, diabetes, mucopolysaccharide and lysosomal disorders, and trisomy 18. Routine examinations consisting of full hand range of motion should be performed in all children. Clinicians should be aware of the importance of conservative treatment options for PTT and PTF and the value of screening for underlying medical conditions associated with PTF.

Non-cardiac Manifestations in Adult Patients With Mucopolysaccharidosis

Mucopolysaccharidoses (MPS) are a heterogeneous group of disorders that results in the absence or deficiency of lysosomal enzymes, leading to an inappropriate storage of glycosaminoglycans (GAGs) in various tissues of the body such as bones, cartilage, heart valves, arteries, upper airways, cornea, teeth, liver and nervous system. Clinical manifestations can become progressively exacerbated with age and affect their quality of life. Developments in advanced supportive treatment options such as enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT) may have improved patients' life span. Adult MPS patients require specialist clinical surveillance long-term. In many cases, in addition to the MPS-related health problems, they may develop age-related complications. Considering the complexity of their clinical manifestations and lack of guidelines on the management of adult MPS disorders, multispecialty and multidisciplinary teams' care is essential to diagnose and treat health problems that are likely to be encountered. This review presents non-cardiac clinical manifestations, their pathophysiology, management and long-term outcomes in adult MPS patients.

Presentation and aetiology of paediatric trigger finger: a systematic review

Paediatric trigger finger is a rare condition distinct from paediatric trigger thumb and adult trigger digits. We performed a systematic review of paediatric trigger finger presentation and aetiology in order to guide workup and management. Fifty-one studies with 193 patients and 398 trigger fingers were included. Most patients had a single, unilateral trigger finger (54%). Fifty-five patients (29%) had an underlying condition, such as mucopolysaccharidosis; these cases appeared to be associated with multiple or bilateral trigger fingers or with carpal tunnel syndrome. All patients with mucopolysaccharidosis were treated surgically. Conservative management was reported in 33% of all patients, and two-thirds of these did not need further intervention. Patients undergoing surgical release infrequently had recurrence of triggering (6%). We propose an algorithmic approach for patients presenting with paediatric trigger finger. Presence of bilateral or multiple trigger digits or concomitant carpal tunnel syndrome should raise suspicion for an atypical underlying pathology.

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.

Ultrasound findings of finger, wrist and knee joints in Mucopolysaccharidosis Type I

INTRODUCTION

Musculoskeletal findings in MPS can progress after enzyme replacement. Our aim was to examine synovial recesses, tendons, retinacula and pulleys using ultrasonography for structural and inflammatory changes.

MATERIAL AND METHODS

The wrist, metacarpophalangeal (MCP), proximal and distal interphalangeal (PIP and DIP) joints, the finger flexor tendons and the knee including entheses of quadriceps and patella tendons were assessed clinically. Ultrasonography of the various synovial recesses of the wrist as well as the extensor retinaculum, carpal tunnel, MCP, PIP and DIP joints of the second finger, extensor and flexor tendons, A1-5 pulleys and the knee joint including relevant entheses followed. Significance of differences between patient values and available normative data were assessed using t-tests.

RESULTS

Ultrasonography showed significant abnormal intraarticular material in the wrist without a clear distribution to synovial recesses and without effusions. Doppler signals were found in a perisynovial distribution and not intrasynovial as expected in in inflammatory arthritis. Findings were similar in the knee but not the fingers. Flexor and extensor tendons were also mostly normal in their structure but significant thickening of retinaculae and the flexor tendon pulleys was seen (p<0.0001 compared to normal).

CONCLUSION

MPS I patients showed intraarticular deposition of abnormal material in the wrist and knee but not in the finger joints where significant thickening of retinaculae/pulleys controlling tendon position was dominant. No ultrasound findings of inflammatory pathology were demonstrated but rather a secondary reaction to abnormal deposition and direct damage of GAG.

[Median nerve compression in the carpal tunnel in children - a delayed diagnosis. About 20 clinical cases]

OBJECTIVES

The carpal tunnel syndrome is rare in children. We performed a retrospective study of 10 children. The aim is to show that the diagnosis of carpal tunnel syndrome is difficult in children.

PATIENTS AND METHODS

We identified all children with median nerve compression in the carpal tunnel between 2010 at 2020, managed in our service.

RESULTS

Ten children with 20 hands included. There was different etiologies of carpal tunnel syndrome: 5 lysosomal storage diseases, 4 idiopathic carpal tunnel syndrome, 1 genodermatose, 1 Byler syndrome and 1 VACTERL syndrome. Common presenting symptoms were pain (five patients) and under use of fingers (five patients). Two children had opposition deficit of the thumb. We operated 19 hands. Median age at diagnosis was 4 years and 7 months. One children or 2 hands had a reanimation of opposition by tendinous transfer of flexor digitorum superficialis tendon of the ring finger. All children had a complete regression of the painful symptoms, a use improvement of fingers and recovery of the opposition of the thumb.

CONCLUSION

The diagnosis of carpal tunnel syndrome is difficult in children. It is common to be confronted with an advanced clinical symptoms. The atypical symptoms may cause diagnostic delay. Due to the quality of the clinical results obtained, we recommend open carpal tunnel release even when the diagnosis seems delayed.

LEVEL OF EVIDENCE

IV.

Hurdles in treating Hurler disease: potential routes to achieve a "real" cure

Mucopolysaccharidoses (MPSs) are multiorgan devastating diseases for which hematopoietic cell transplantation (HCT) and, to a lesser extent, enzyme replacement therapy have substantially altered the course of the disease. Furthermore, they have resulted in increased overall survival, especially for Hurler disease (MPS-1). However, despite the identification of clinical predictors and harmonized transplantation protocols, disease progression still poses a significant burden to patients, although at a slower pace. To design better therapies, we need to understand why and where current therapies fail. In this review, we discuss important aspects of the underlying disease and the disease progression. We note that the majority of progressive symptoms that occur in "hard-to-treat" tissues are actually tissues that are difficult to reach, such as avascular connective tissue or tissues isolated from the circulation by a specific barrier (eg, blood-brain barrier, blood-retina barrier). Although easily reached tissues are effectively cured by HCT, disease progression is observed in these "hard-to-reach" tissues. We used these insights to critically appraise ongoing experimental endeavors with regard to their potential to overcome the encountered hurdles and improve long-term clinical outcomes in MPS patients treated with HCT.

Trigger finger in children with hurler syndrome - distribution pattern and treatment options

Introduction: Mucopolysaccharidosis is a rare and congenital autosomal recessive lysosomal storage disorder of glycosaminoglycans. An enzyme defect leads to cell, tissue and organ dysfunction. Carpal tunnel syndrome and trigger finger are the results of mucopolysaccharid deposition.

Material and methods: We are treating 6 patients with mucopolysaccharide associated trigger fingers in an interdisciplinary setting with the department of pediatric hematology and oncology at Hannover Medical School, where each patient is examined inter alia for symptoms of trigger finger annually.

Besides an interview of the parents about abnormalities with regard to hand function, pain and/or neurologic symptoms the children are examined by palpation and by assessment of the active and passive range of finger motion.

In the case of finger locking due to an impaired excursion of the flexor tendons in the A2 and A3 pulley region, we performed a trap-door incision technique for A2 pulley widening and a simple release of the A3 pulley.

Results: In 6 patients 43 fingers were affected. The average age was 10 years. Pulley thickening was palpated in 19 fingers of to the left hand and 24 fingers of the right hand. In 7 fingers the A1 pulley was affected, in 28 fingers the A2 pulley and in 25 fingers the A3 pulley. The A4 and A5 pulley were not affected in any case. Trigger symptoms were seen in 13 fingers. Five of the 6 children were given an operation indication. In these cases we performed carpal tunnel release, release of Loge de Guyon, and trigger finger release, either in combination or alone. In all cases the procedure led to pain relief and functional improvement.

Conclusion: The treatment of trigger fingers in children with mucopolysaccharidosis as a rare disease is challenging with regard to diagnostics and indication.

The main treatment goal is pain relief and improvement of hand function.

Outcomes of Pediatric and Adolescent Carpal Tunnel Release

PURPOSE

To investigate carpal tunnel syndrome (CTS) presentation and long-term outcomes of carpal tunnel release (CTR) in children and adolescents.

METHODS

All pediatric and adolescent patients who underwent CTR between February 2003 and June 2018 were identified. Patients were grouped by etiology: lysosomal storage disease (11 hands), idiopathic (6 hands), acute traumatic (7 hands), delayed traumatic (5 hands) and tumorous (2 hands). Medical records were reviewed for presenting symptoms and preoperative treatments. Final outcomes were assessed via phone interviews, chart review, the Boston Carpal Tunnel Questionnaire (BCTQ), and Patient-Reported Outcomes Measurement Information System (PROMIS) scores.

RESULTS

All 25 patients (31 hands) identified were included in the study; median age at surgery was 12.7 years (range, 2.5-23.3 years). Eighteen patients completed surveys at a median of 4.7 years after surgery (range, 8 months-16 years). Common presenting symptoms in lysosomal storage disease were numbness/tingling (7 hands); pain was only reported in 1 hand. The most frequent indication for acute traumatic CTR (7 hands) was palmar hand swelling at the carpal tunnel (4 hands). Delayed traumatic and idiopathic CTS most often presented with numbness/tingling (4 hands and 6 hands, respectively) and pain (3 hands, 4 hands, respectively). Of the original 4 lysosomal storage disease surgeries included in long-term follow-up, all experienced gradual recurrence of symptoms after years of relief (range, 3-14 years). Two patients underwent revision CTR and were symptom-free at follow-up. All patients with acute traumatic and tumorous etiologies had full resolution of symptoms. Delayed traumatic and idiopathic etiologies frequently experienced recurrent or recalcitrant symptoms (4 of 5 and 3 of 6 surgeries, respectively).

CONCLUSIONS

Carpal tunnel release often alleviates symptoms in children with lysosomal storage disease for years to decades. Carpal tunnel release successfully relieves symptoms in acute traumatic cases, but is not always sufficient to relieve symptoms associated with delayed traumatic etiologies. Approximately half of patients with idiopathic CTS experience recalcitrant or recurrent symptoms.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Mucopolysaccharidoses I and II: Brief Review of Therapeutic Options and Supportive/Palliative Therapies

Purpose. Mucopolysaccharidoses (MPS) are group of inherited lysosomal storage diseases caused by mutations of enzymes involved in catalyzing different glycosaminoglycans (GAGs). MPS I and MPS II exhibit both somatic and neurological symptoms with a relatively high disease incidence. Hematopoietic stem cell therapy (HSCT) and intravenous enzyme replacement therapy (ERT) have had a significant impact on the treatment and comprehension of disease. This review is aimed at providing a comprehensive evaluation of the pros and cons of HSCT and ERT, as well as an up-to-date knowledge of new drugs under development. In addition, multiple disease management strategies for the uncontrollable manifestations of MPS I and MPS II to improve patients' quality of life are presented. Findings. Natural history of MPS I and MPS II shows that somatic and neurological symptoms occur earlier in severe forms of MPS I than in MPS II. ERT increases life expectancy and alleviates some of the somatic symptoms, but musculoskeletal, ophthalmological, and central nervous system (CNS) manifestations are not controlled. Additionally, life-long treatment burdens and immunogenicity restriction are unintended consequences of ERT application. HSCT, another treatment method, is effective in controlling the CNS symptoms and hence has been adopted as the standard treatment for severe types of MPS I. However, it is ineffective in MPS II, which can be explained by the relatively late diagnosis. In addition, several factors such as transplant age limits or graft-versus-host disease in HSCT have limited its application for patients. Novel therapies, including BBB-penetrable-ERT, gene therapy, and substrate reduction therapy, are under development to control currently unmanageable manifestations. BBB-penetrable-ERT is being studied comprehensively in the hopes of being used in the near future as a method to effectively control CNS symptoms. Gene therapy has the potential to “cure” the disease with a one-time treatment rather than just alleviate symptoms, which makes it an attractive treatment strategy. Several clinical studies on gene therapy reveal that delivering genes directly into the brain achieves better results than intravenous administration in patients with neurological symptoms. Considering new drugs are still in clinical stage, disease management with close monitoring and supportive/palliative therapy is of great importance for the time being. Proper rehabilitation therapy, including physical and occupational therapy, surgical intervention, or medications, can benefit patients with uncontrolled musculoskeletal, respiratory, ophthalmological, and neurological manifestations.

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.

Screening for Carpal Tunnel Syndrome in Patients With Mucopolysaccharidosis

Mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage diseases with multisystem manifestations, including carpal tunnel syndrome (CTS). This study comprised a systematic review of literature and hospital guidelines addressing the method and frequency of screening for carpal tunnel syndrome in mucopolysaccharidosis patients and a review of carpal tunnel syndrome in patients seen in the multidisciplinary mucopolysaccharidosis clinic of a pediatric hospital, in order to develop screening recommendations. The literature reported the importance of routine carpal tunnel syndrome screening from early childhood in patients with mucopolysaccharidosis I, II, IV, and VI. Screening methods included physical examination, nerve conduction studies, electromyography, and ultrasonography. Ten of 20 mucopolysaccharidosis patients in our series underwent carpal tunnel syndrome surgery. Given the high incidence of carpal tunnel syndrome at a young age in mucopolysaccharidosis, the authors recommend performing physical examination and obtaining patient and caregiver history for carpal tunnel syndrome every 6 months from the time of mucopolysaccharidosis diagnosis, supplemented by annual nerve conduction studies in cases with poor history or equivocal examination.

Mucopolysaccharidosis Type I in Children, a Forgotten Diagnosis Responsible for Undiagnosed Musculoskeletal Complaints: Report of Two Cases

Mucopolysaccharidoses (MPS) are a subgroup of lysosomal storage disorders. The underlying mechanism of MPS disorders are deficiency in specific enzymes which leads to accumulation of partially degraded glycosaminoglycans (GAGs) in various tissues. A wide variety of manifestations are reported but musculoskeletal complaints are common among them. In milder forms of MPS, musculoskeletal complaints are presenting symptoms. Delays in diagnosis due to unspecific and mild symptoms is common. Misdiagnosis of MPS as juvenile idiopathic arthritis and other inflammatory arthritis disorders is frequent. Early diagnosis and treatment prevents irreversible cellular damages and is a key factor in efficacy of enzyme replacement therapy. In this study we described two MPS patients with musculoskeletal complaints who were not diagnosed for a period of time. Although musculoskeletal manifestation are common in a variety of clinical conditions, their presence at low ages or co-occurrence of other manifestations (such as cardiac, respiratory, neurologic, etc.) in multiple systems should prompt evaluation of patients for MPS and other metabolic disorders. The rheumatologists' awareness on MPS should be promoted to achieve timely diagnosis and subsequent early treatment.

Diagnosis and Management of Carpal Tunnel Syndrome in Children with Mucopolysaccharidosis: A 10 Year Experience

INTRODUCTION

Mucopolysaccharidoses (MPS) are rare and clinically heterogeneous lysosomal storage disorders. Carpal tunnel syndrome (CTS) is a frequent complication in MPS types I, II, VI, and VII. CTS symptoms are difficult to recognize in these children, and often there is a lack of appropriate investigations.

PATIENTS AND METHODS

In this retrospective study, all MPS patients were referred to the electrodiagnostic (EDX) laboratory of a single academic center during a 10-year period. Forty-eight children underwent serial EDX studies for CTS diagnosis and follow-up after surgery. Forty-two patients were diagnosed with CTS. Sensory nerve conduction velocity (SNCV), distal motor latency (DML), and motor nerve conduction velocity through the wrist (MNCV-W) of the median nerve were reviewed and analyzed.

RESULTS

One-hundred-three EDX examinations were performed on 48 patients. The median age at disease diagnosis was 2.1 years versus 4.9 years for CTS diagnosis. Analysis of the series revealed that electrophysiological abnormalities of CTS could have started much earlier (before the age of 2 years or at diagnosis of MPS). Diagnosis was based on SNCV and DML results, and MNCV-W was taken into consideration. Bilateral CTS was frequent (88%) in the types of MPS studied in our population and was observed from the first year of life, and may not have be associated with obvious clinical symptoms. EDX studies also helped in the follow-up and detection of CTS relapses, thus leading to an early intervention allowing a better recovery.

CONCLUSION

EDX studies should be performed promptly and regularly in these patients. Prospective studies are required in order to understand the effect of disease-specific therapies in preventing the development of CTS in these patients.

SYNOPSIS

EDX studies should be performed in MPS patients soon after diagnosis and during routine follow-up, before and after surgical decompression.

Scoping review of symptoms in children with rare, progressive, life-threatening disorders

BACKGROUND

Q3 conditions are progressive, metabolic, neurological or chromosomal childhood conditions without a cure. Children with these conditions face an unknown lifespan as well as unstable and uncomfortable symptoms. Clinicians and other healthcare professionals are challenged by a lack of evidence for symptom management for these conditions.

AIMS

In this scoping review, we systematically identified and mapped the existing literature on symptom management for children with Q3 conditions. We focused on the most common and distressing symptoms, namely alertness, behavioural problems, bowel incontinence, breathing difficulties, constipation, feeding difficulties, sleep disturbance, temperature regulation, tone and motor problems and urinary incontinence. For children with complex health conditions, good symptom management is pertinent to ensure the highest possible quality of life.

METHODS

Scoping review. Electronic database searches in Ovid MEDLINE, Embase and CINAHL and a comprehensive grey literature search.

RESULTS

We included 292 studies in our final synthesis. The most commonly reported conditions in the studies were Rett syndrome (n=69), followed by Cornelia de Lange syndrome (n=25) and tuberous sclerosis (n=16). Tone and motor problems were the most commonly investigated symptom (n=141), followed by behavioural problems (n=82) and sleep disturbance (n=62).

CONCLUSION

The evidence for symptom management in Q3 conditions is concentrated around a few conditions, and these studies may not be applicable to other conditions. The evidence is dispersed in the literature and difficult to access, which further challenges healthcare providers. More research needs to be done in these conditions to provide high-quality evidence for the care of these children.

Recommendations for the management of MPS VI: systematic evidence- and consensus-based guidance

Introduction

Mucopolysaccharidosis (MPS) VI or Maroteaux-Lamy syndrome (253200) is an autosomal recessive lysosomal storage disorder caused by deficiency in N-acetylgalactosamine-4-sulfatase (arylsulfatase B). The heterogeneity and progressive nature of MPS VI necessitates a multidisciplinary team approach and there is a need for robust guidance to achieve optimal management. This programme was convened to develop evidence-based, expert-agreed recommendations for the general principles of management, routine monitoring requirements and the use of medical and surgical interventions in patients with MPS VI.

Methods

26 international healthcare professionals from various disciplines, all with expertise in managing MPS VI, and three patient advocates formed the Steering Committee group (SC) and contributed to the development of this guidance. Members from six Patient Advocacy Groups (PAGs) acted as advisors and attended interviews to ensure representation of the patient perspective. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with expertise and experience managing patients with MPS VI and the manuscript has been evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers.

Results

A total of 93 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions. Consensus was reached on all statements after two rounds of voting. The greatest challenges faced by patients as relayed by consultation with PAGs were deficits in endurance, dexterity, hearing, vision and respiratory function. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance).

Conclusion

This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS VI and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1080-y) contains supplementary material, which is available to authorized users.

Flexor Tendon Entrapment Caused by Intratendinous Tumor-Like Chronic Proliferative Tenosynovitis

The flexor tendon can be enlarged in chronic tenosynovitis, and it may sometimes trigger flexor tendon entrapment, but there have been no reports of its evaluation on preoperative imaging or postoperative pathologic examination. The case of a 54-year-old man who suffered flexor tendon entrapment due to intratendinous tumor-like tissue between the first and second annular pulleys, which was identified on magnetic resonance imaging preoperatively, is described. Ulnar superficialis slip resection and reduction flexor tenoplasty of flexor digitorum profundus were effective procedures for the release of flexor tendon entrapment under wide-awake surgery with local anesthesia. On postoperative pathologic examination, chondroid metaplasia was identified, in association with infiltration of chondrocytes and inflammatory cells into the flexor tendon fibers and tenosynovium. Preoperative imaging was useful in a case of chronic or severe tenosynovitis to assess the condition of flexor tendons, and wide-awake surgery was the appropriate procedure for the treatment of this case.

Tarsal tunnel syndrome in the mucopolysaccharidoses: A case series and literature review

BACKGROUND

The mucopolysaccharidoses (MPS) are a group of inherited, progressive, multi-system lysosomal storage disorders. Musculoskeletal manifestations include nerve entrapment syndromes, most commonly carpal tunnel syndrome. Tarsal tunnel syndrome (TTS) has also been reported. The purpose of this study was to investigate the clinical course of MPS patients with suspected TTS and to conduct a literature review of TTS in MPS.

METHODS

A review of the Medline and EMBASE databases was conducted in accordance with published guidelines from the Joanna Briggs Institute of Evidence Based Medicine with search strategy developed by a librarian trained in systematic reviews. A medical record review was undertaken for all patients managed in the multi-disciplinary MPS clinic in a tertiary referral paediatric centre, identifying patients with a suspected or established diagnosis of TTS. Data regarding the demographics, investigations, presentation, management, and clinical course were collected.

RESULTS

The literature review failed to identify any published papers regarding TTS in MPS, with conference proceedings only identified. Within a cohort of 19 MPS patients, four patients with a suspected diagnosis of TTS were identified (MPS I: two patients, MPS VI: two patients). Three patients underwent surgical tarsal tunnel decompression, two with good result. One patient had overlapping symptoms with spinal stenosis and improvement in suspected tarsal tunnel symptoms following spinal decompression and fusion.

Association between Stenosing Tenosynovitis and Dupuytren's Contracture in the Hand

Background:

Both stenosing tenosynovitis and Dupuytren’s contracture are common conditions encountered in hand surgery. Connections between 2 diseases have been suggested in literature. The purpose of this study was to examine whether there’s an association between the 2 processes.

Methods:

A retrospective chart review was performed to include all patients seen by a single surgeon between 2014 and 2017 with the diagnosis of either trigger finger or Dupuytren’s contracture in the same hand. Patients’ demographics, medical history, social and surgical histories are recorded. Univariate and multivariate analysis were conducted.

Results:

A cohort of 238 patients was identified. One hundred ninety-two patients were diagnosed with trigger finger. Eighty-nine patients were diagnosed with Dupuytren’s contracture. Forty-three patients carried both diagnoses. Median age was 61.6 (56–72). Half were male (50.4%) and 66.8% reported current alcohol intake. Other factors include history of former or current tobacco use (52.9%), diabetes (23.9%), and manual labor (31.1%). In the univariate model, trigger finger, sex, and age were significantly associated with the diagnosis of Dupuytren’s contracture, and Dupuytren’s contracture and sex were significantly associated with the trigger finger diagnosis. Diabetes, manual labor, use of alcohol and tobacco were not significant. In the multivariate model, age and trigger finger were significantly associated with Dupuytren’s contracture.

Conclusions:

Significant association between stenosing tenosynovitis and Dupuytren’s contracture was identified in our patient cohort. Patients with stenosing tenosynovitis may be at an increased risk of developing Dupuytren’s contracture or vice versa.

Early detection of median nerve compression by Electroneurography can improve outcome in children with Mucopolysaccharidoses

Background

Carpal tunnel syndrome (CTS) is a common complication of the mucopolysaccharidoses. In severe or attenuated mucopolysaccharidoses patients, clinical symptoms of CTS usually appear at a late stage of median nerve compression. Relying on CTS symptoms is often too late and there is a risk of axonal damage and further irreversible sequelae. Electroneurography is a powerful technique to detect the initial preclinical signs of median nerve compression. In a retrospective series of 13 children with mucopolysaccharidoses (10 Hunter, one Hurler-Scheie and 2 Hurler children), we describe the electroneurography progression of CTS (43 hand evaluations) and the severity of median nerve damage.

Results

The average age at mucopolysaccharidoses diagnosis was 33.6 months (11–66 months). Clinical signs of CTS appeared on average 44.6 months (0–73 months) after diagnosis of mucopolysaccharidoses. Electroneurography anomalies suggestive of CTS appeared as early as the age of 3.5 years and probably preceded clinical signs of CTS. Median nerve compression was bilateral and distal, initially on the sensory pathway then becoming motor-sensory. Beyond a threshold of 14 m/sec median distal motor nerve conduction velocity (MNCV_d) and index of terminal latency (MNCVd/MNCVp) of 0.27, there was true distal conduction slowdown.

Conclusions

To prevent irreversible sequelae of median nerve compression, we suggest annual electroneurography testing for mucopolysaccharidoses patients starting as early as 3 years of age, including both motor and sensory nerve pathways, on median and, in reference to the ulnar nerves, bilaterally at the wrist and the elbow. Timely surgical intervention can greatly improve the overall function and quality of life of these patients.

Carpal tunnel syndrome in mucopolysaccharidosis I: a registry-based cohort study

AIM

To characterize carpal tunnel syndrome (CTS) in patients with mucopolysaccharidosis I (MPS I).

METHOD

Data were included for patients with MPS I who had either nerve conduction examination that included a diagnosis of CTS or who had CTS release surgery. Although this represented a subset of patients with CTS in the MPS I Registry, the criteria were considered the most objective for data analysis.

RESULTS

As of March 2016, 994 patients were categorized with either severe (Hurler syndrome) or attenuated (Hurler-Scheie or Scheie syndromes) MPS I. Among these, 291 had a CTS diagnosis based on abnormal nerve conduction (n=54) or release surgery (n=237). Median ages (minimum, maximum) at first CTS diagnosis were 5 years 2 months (10mo, 16y 2mo) and 9y 11mo (1y 8mo, 44y 1mo) for patients with severe and attenuated MPS I respectively. Most patients had their first CTS diagnosis after MPS I diagnosis (94%) and treatment (hematopoietic stem cell transplant and/or enzyme replacement therapy) (74%). For 11% of patients with attenuated disease, CTS diagnosis preceded MPS I diagnosis by a mean of 7 years 6 months.

INTERPRETATION

CTS is a rare complication in pediatric patients and should alert medical care providers to the potential diagnosis of MPS I. Significant delays exist between diagnosis of CTS and MPS I for patients with attenuated disease.

WHAT THIS PAPER ADDS

There are significant delays in diagnosing carpal tunnel syndrome (CTS) in patients with mucopolysaccharidosis I (MPS I). Enzyme replacement therapy or hematopoietic stem cell transplant do not prevent the development of CTS. Testing for CTS in patients with MPS I is recommended to prevent irreparable damage. CTS in pediatric patients should alert physicians to potential diagnosis of MPS I.

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.

Carpal Tunnel Syndrome in the Setting of Mucopolysaccharidosis II (Hunter Syndrome)

BACKGROUND

Carpal tunnel syndrome (CTS) is a rare finding in children, but heavily represented in pediatric patients with mucopolysaccharidoses. Diagnosis is a challenge due to lack of the stereotypical symptomatic complaints and relies on examination and objective nerve conduction studies.

METHODS

We present a case of delayed presentation of CTS in a 12-year-old boy with Hunter syndrome, followed by a review of the literature.

RESULTS

Patient Z.D. presented with minimal reported CTS symptoms but advanced median nerve damage on electromyography. He underwent bilateral carpal tunnel release with median nerve neurolysis and flexor tenosynovectomies. Intraoperative examination demonstrated the presence of a "waist sign" of the median nerve and moderate flexor tenosynovial hypertrophy bilaterally. Parents reported mild subjective improvement of dexterity and fine motor skills postoperatively.

CONCLUSION

To optimize functional outcome, routine screening for CTS and intervention at an early age are emphasized in the mucopolysaccharidoses population.

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.

The Frequency of Carpal Tunnel Syndrome in Hurler Syndrome After Peritransplant Enzyme Replacement Therapy: A Retrospective Comparison

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.

Unique medical issues in adult patients with mucopolysaccharidoses

The mucopolysaccharidoses are a group of inherited metabolic diseases caused by deficiencies in enzymes involved in the sequential degradation of glycosaminoglycans (GAGs) leading to substrate accumulation in various tissues and organs. GAG accumulation can cause growth retardation and progressive damage to respiratory, cardiovascular, musculoskeletal, nervous, gastrointestinal, auditory, and visual systems. In the past, few people with severe phenotypic mucopolysaccharidosis (MPS) reached adulthood. However, better methods for diagnosis, multi-disciplinary care, and new therapies have extended lifespan, leading to an increasing number of patients surviving beyond childhood. The growing number of adult MPS patients poses significant challenges for clinicians who may not be familiar with the clinical manifestations of MPS. In addition, as new interventions have changed the natural history of these disorders, it is difficult to anticipate both the impact on life expectancy and other complications that may occur as these patients age. Because the MPS disorders are multi-organ diseases, their management requires a coordinated multi-disciplinary approach. Here we discuss the unique pattern of medical issues and multi-organ involvement in adult patients with MPS and identify the challenges that are associated with management of MPS. This review is based on information from an expert investigator meeting with MPS specialists held October 2-4, 2014 in Dublin, Ireland, as well as on current literature searches focusing on MPS and adults.

Musculoskeletal manifestations in mucopolysaccharidosis type I (Hurler syndrome) following hematopoietic stem cell transplantation

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for young Hurler patients. Despite halting of neurocognitive decline and improvement of life expectancy, the beneficial effect on the skeletal system is limited. As orthopedic complications are one of the most disabling factors following HSCT, this points to the need for new treatment strategies. The study summarizes musculoskeletal manifestations in 19 transplanted Hurler patients.

METHODS

Data were obtained retrospectively. Patients' charts for physical examinations of the joint range of motion (JROM) of shoulders, elbows, hips and knees were reviewed. Radiographic evaluations of thorax, spine, pelvis and hands were performed. MRI scans of the craniocervical junction were analyzed to determine odontoid hypoplasia and the prevalence of craniocervical stenosis.

RESULTS

Nineteen Hurler patients (10 females, 9 males) with an average age of 8.1 years (range 2.5-23.8) at the latest follow-up, who underwent allogenic HSCT between 1991 and 2012, were assessed after an average follow-up period of 6.4 years (range 0.7-22.5). Seventeen patients achieved long-term engraftment, two developed graft failures. The majority of patients showed a steady state or improvements in the mobility of knees (31 %/63 %), hips (47 %/40 %) and elbows (56 %/38 %). However, shoulder abduction was impaired in ¾ of patients and showed the highest rate of progression (31 %). In patients with graft failure, progressive restrictions in JROM were noted. Assessments of the craniocervical junction by MRI showed stable or improved diameters in 67 % of patients. Correction or stabilization of odontoid hypoplasia was found in 64 %. However thoracolumbar kyphosis, scoliosis, hip dysplasia and genua valga were progressive despite HSCT. At the last follow up, 47 % of patients were partially wheelchair dependent, 10 % wheelchair bound and 25 % regularly experienced pain in the spine, hips and lower extremities due to orthopedic problems.

CONCLUSION

Joint mobility, odontoid hypoplasia and craniocervical stenosis might stabilize or even improve in Hurler patients following HSCT. However, despite the beneficial effects on some musculoskeletal manifestations, skeletal complications are frequently observed and the overall burden of orthopedic disease is significant. Frequent multi-disciplinary follow-up in a specialized center are essential. Novel therapeutic approaches (e.g. anti-inflammatory drugs) are needed to improve musculoskeletal outcomes.

Pediatric Trigger Digits

Pediatric trigger thumb presents not at birth but early in childhood. Most evidence suggests that it is caused by a developmental size mismatch between the flexor pollicis longus tendon and its sheath. Patients generally present with the thumb interphalangeal joint locked in flexion. Surgical reviews report near universally excellent outcomes after open release of the A1 pulley. However, recent reports indicate that there may be a role for nonsurgical treatment for families that are willing to wait several years for possible spontaneous resolution of the deformity. Triggering in digits other than the thumb in children is generally associated with an underlying diagnosis including anatomic abnormalities of the tendons, and metabolic, inflammatory, and infectious etiologies. Although some have advocated nonsurgical treatment, surgery is often necessary to address the underlying anatomic etiology. More extensive surgery beyond simple A1 pulley release is often required, including release of the A3 pulley and resection of a slip of the flexor digitorum superficialis tendon.

Five-Years Trigger Finger Due to Partial Flexor Tendon Laceration in a Child

Trigger finger (TF) is a condition that affects quality of life and one of the most common causes of hand pain and disability. TF is characterized by catching, snapping or locking of the involved finger flexor tendon, associated with pain. TF in the children occurs rarely than in adults and partial tendon laceration is an uncommon cause of TF in the children. Thus, our aim in this study to define TF due to partial flexor tendon laceration in a child.

Long-Term Results of Carpal Tunnel and Trigger Finger Releases in a Patient with Hurler Syndrome

CASE

Prior to the emergence of bone marrow transplantation as a treatment for Hurler syndrome, most individuals with this syndrome did not survive into their teenage years. We describe a twenty-three-year-old patient with Hurler syndrome who had been treated with bone marrow transplantation; we focus on the presentation and treatment of the associated carpal tunnel syndrome and trigger digits. After initial trigger digit release and revision bilateral carpal tunnel release with a tenosynovectomy, he maintained symptom-free hand function.

CONCLUSION

Surgical treatment of median nerve compression and trigger digits due to Hurler syndrome is effective in the long term.

Mucopolysaccharidoses

The mucopolysaccharidoses (MPSs) are a group of rare genetic disorders of glycosaminoglycan catabolism, caused by a deficiency of lysosomal enzymes required for GAG degradation. Incomplete breakdown of glycosaminoglycans leads to progressive accumulation of these substances in many tissues throughout the body. Different residual enzymatic activity can result in different phenotypes of the same MPS disorder, from severe to attenuated. Musculoskeletal manifestations are common across all forms of MPS. Skeletal and joint abnormalities are prominent features of many MPS disorders, particularly attenuated phenotypes. However, diagnostic delays occur frequently for patients with an MPS, especially those with more attenuated forms of disease. In the absence of appropriate treatment, these conditions are chronic, progressive and often debilitating, but treatment for many types of MPS is now available. Therefore, increasing awareness of MPS among rheumatologists is extremely important.

Bilateral carpal tunnel syndrome and multiple trigger fingers in a child with mucolipidosis Type III disease

This report presents a five-year-old girl with mucolipidosis Type III disease who had bilateral carpal tunnel syndrome and eight trigger fingers. Bilateral open carpal tunnel release was performed. The trigger fingers were treated with A1 and A3 pulleys release and the ulnar slips of the flexor digitorum superficialis tendons were removed.

Management of pediatric trigger thumb and trigger finger

Pediatric trigger thumb and trigger finger represent distinct conditions and should not be treated like adult acquired trigger finger. Over the last two decades, our understanding of the natural history of pediatric trigger thumb and the etiology and surgical management of pediatric trigger finger has improved. Pediatric trigger thumb may spontaneously resolve, although resolution may take several years. Open surgical release of the A1 pulley of the thumb is an alternative option that nearly uniformly restores thumb interphalangeal joint motion. Surgical management of pediatric trigger finger with isolated release of the A1 pulley has been associated with high recurrence rates. Awareness of the anatomic factors that may contribute to triggering in the pediatric finger and willingness to explore and address other involved components of the flexor mechanism can prevent surgical failure.

Diagnosis of the mucopolysaccharidoses

The mucopolysaccharidoses (MPSs) often present a diagnostic challenge, particularly for patients who have more slowly progressive disease phenotypes, as early disease manifestations can be subtle or non-specific. However, certain types of bone and joint involvement should always prompt consideration of an MPS diagnosis, such as early joint involvement without classic inflammatory features or erosive bone lesions, claw hand, spinal deformities or dysostosis multiplex. All such patients should be referred to a geneticist or metabolic specialist for diagnostic evaluation. The earlier the diagnosis is made, the better the potential outcome of treatment. Each type of MPS is associated both with deficient activity of a specific lysosomal enzyme that degrades specific glycosaminoglycans (GAGs) and with abnormalities in urinary GAG excretion. MPS patients usually excrete excess GAG in urine and/or have different relative proportions of types of GAG in urine as compared with age-matched normal subjects. Although urinary GAG analyses (both quantitative and qualitative) can suggest the most likely type of MPS, diagnosis must be confirmed by enzyme assay. Multiple assays may be necessary to identify the disease subtype. Correct identification of the MPS type is essential to guide treatment and management decisions.

Mucopolysaccharidosis type II: European recommendations for the diagnosis and multidisciplinary management of a rare disease

Mucopolysaccharidosis type II (MPS II) is a rare, life-limiting, X-linked recessive disease characterised by deficiency of the lysosomal enzyme iduronate-2-sulfatase. Consequent accumulation of glycosaminoglycans leads to pathological changes in multiple body systems. Age at onset, signs and symptoms, and disease progression are heterogeneous, and patients may present with many different manifestations to a wide range of specialists. Expertise in diagnosing and managing MPS II varies widely between countries, and substantial delays between disease onset and diagnosis can occur. In recent years, disease-specific treatments such as enzyme replacement therapy and stem cell transplantation have helped to address the underlying enzyme deficiency in patients with MPS II. However, the multisystem nature of this disorder and the irreversibility of some manifestations mean that most patients require substantial medical support from many different specialists, even if they are receiving treatment. This article presents an overview of how to recognise, diagnose, and care for patients with MPS II. Particular focus is given to the multidisciplinary nature of patient management, which requires input from paediatricians, specialist nurses, otorhinolaryngologists, orthopaedic surgeons, ophthalmologists, cardiologists, pneumologists, anaesthesiologists, neurologists, physiotherapists, occupational therapists, speech therapists, psychologists, social workers, homecare companies and patient societies.

Take-home message

Expertise in recognising and treating patients with MPS II varies widely between countries. This article presents pan-European recommendations for the diagnosis and management of this life-limiting disease.

Orthopaedic management of Hurler's disease after hematopoietic stem cell transplantation: a systematic review

OBJECTIVE

The introduction of hematopoietic stem cell transplantation (HSCT) has significantly improved the life-span of Hurler patients (mucopolysaccharidosis type I-H, MPS I-H). Yet, the musculoskeletal manifestations seem largely unresponsive to HSCT. In order to facilitate evidence based management, the aim of the current study was to give a systematic overview of the orthopaedic complications and motor functioning of Hurler's patients after HSCT.

METHODS

A systematic review was conducted of the medical literature published from January 1981 to June 2010. Two reviewers independently assessed all eligible citations, as identified from the Pubmed and Embase databases. A pre-developed data extraction form was used to systematically collect information on the prevalence of radiological and clinical signs, and on the orthopaedic treatments and outcomes.

RESULTS

A total of 32 studies, including 399 patient reports were identified. The most frequent musculoskeletal abnormalities were odontoid hypoplasia (72%), thoracolumbar kyphosis (81%), genu valgum (70%), hip dysplasia (90%) and carpal tunnel syndrome (63%), which were often treated surgically during the first decade of life. The overall complication rate of surgical interventions was 13.5%. Motor functioning was further hampered due to reduced joint mobility, hand dexterity, motor development and longitudinal growth.

CONCLUSION

Stem cell transplantation does not halt the progression of a large range of disabling musculoskeletal abnormalities in Hurler's disease. Although prospective data on the quantification, progression and treatment of these deformities were very limited, early surgical intervention is often advocated. Prospective data collection will be mandatory to achieve better evidence on the effect of treatment strategies.

High prevalence of carpal tunnel syndrome in children with mucopolysaccharidosis type II (Hunter syndrome)

Although carpal tunnel syndrome (CTS) is the most common compressive neuropathy seen in the upper extremity of adults, it is rarely seen in children. Several reports have shown that mucopolysaccharidosis type II (Hunter syndrome), a rare genetic disorder, is one of the causes of CTS in children. Usual symptoms of CTS are pain, weakness, and paresthesias in the hand and digits. However, the diagnosis of CTS in Hunter syndrome is often delayed or unrecognized because of atypical symptoms and cognitive impairment. Here, we report the prevalence, clinical manifestation, and nerve conduction profiles of CTS in 45 Hunter syndrome patients. The mean age of the study participants was 117.1 (74.9) months (range: 4-408 months); all patients were male. Forty-three (96.0%) of the 45 patients with Hunter syndrome had CTS. Bilateral CTS was observed in all patients; 73 (82.0%) of the patients' hands had severe degree of CTS. Intriguingly, in contrast with other nerve velocities, decreases in forearm conduction velocities of the median nerve were observed in 28 (31.5%) of 89 hands with CTS. There was a significant difference in age (P < 0.001) between hands with normal, mild, moderate, and severe grades of CTS. The compound muscle action potential and sensory nerve action potential amplitudes of the median nerves decreased with age (CMAP, r = -0.526, P < 0.001; SNAP, r = -0.564, P < 0.001). Early recognition and intervention to ameliorate the symptoms of CTS are important in improving the quality of life of Hunter syndrome patients.

[Trigger digits]

Trigger finger is an entity seen commonly by hand surgeons. It is produced by a size mismatch between the flexor tendon and the A1 pulley, which causes pain, clicking, catching, and loss of motion of the affected finger. The diagnosis is usually easy but other pathological processes (extensor apparatus instability, locked metacarpo-phalangeal joint) must be excluded. Treatment modalities in trigger finger include splinting, corticosteroid injection and/or surgery. Indication depends on the clinical form of trigger finger.