Thoracolumbar kyphosis in patients with mucopolysaccharidoses: clinical outcomes and predictive radiographic factors for progression of deformity

The surgical management of spinal disorders in lysosomal storage diseases: a systematic review

BACKGROUND

The skeletal manifestations of lysosomal storage diseases (LSDs) are largely refractory to available therapeutic modalities. Consequently, there is an increasing need to manage their spinal deformities. The aim was to perform a systematic review to answer the questions, "What are the reported indications for surgery for spinal deformity in patients with LSDs?" and "what are the published surgical management strategies?".

METHODS

Articles that made reference to at least one LSD, a spinal abnormality and surgical management were included. Extracted study data included: study type, sample size, methodology and year of publication. The following clinical information was collected: demographics, spinal abnormalities, and surgical indications, details and outcomes.

RESULTS

Thirty-seven articles were included, with 23 describing surgical management of craniocervical manifestations seen in mucopolysaccharidosis. Radiological evidence of myelopathy at the craniocervical junction and/or progressive clinical neurological compromise were accepted as surgical indications. Prophylactic surgery was proposed by some authors. The recommended surgical technique and whether to stabilise and/or decompress varied between articles and LSD types. Twenty-one articles discussed thoracolumbar pathology, including thoracolumbar kyphosis and scoliosis. Radiological severity, progression of deformity, and presence of neurological deterioration were discussed as surgical indications. Most papers recommended circumferential arthrodesis via combined anterior and posterior approaches.

CONCLUSION

The surgical management of spinal disorders in LSDs remains controversial. Centres managing these patients should be encouraged to have a standardised system of reporting outcomes, to facilitate recommendations for management of the spinal manifestations.

Incidence of spinal deformity surgery in a national health service from 2005 to 2018: an analysis of 2,205 children and adolescents

Aims

Severe spinal deformity in growing patients often requires surgical management. We describe the incidence of spinal deformity surgery in a National Health Service.

Methods

Descriptive study of prospectively collected data. Clinical data of all patients undergoing surgery for spinal deformity between 2005 and 2018 was collected, compared to the demographics of the national population, and analyzed by underlying aetiology.

Results

Our cohort comprised 2,205 patients; this represents an incidence of 14 per 100,000 individuals among the national population aged between zero and 18 years. There was an increase in mean annual incidence of spinal deformity surgery across the study period from 9.6 (7.2 to 11.7) per 100,000 individuals in 2005 to 2008, to 17.9 (16.1 to 21.5) per 100,000 individuals in 2015 to 2018 (p = 0.001). The most common cause of spinal deformity was idiopathic scoliosis accounting for 56.7% of patients. There was an increase in mean incidence of surgery for adolescent idiopathic scoliosis (AIS) (from 4.4 (3.1 to 5.9) to 9.8 (9.1 to 10.8) per 100,000 individuals; p < 0.001), juvenile idiopathic scoliosis (JIS) (from 0.2 (0.1 to 0.4) to one (0.5 to 1.3) per 100,000 individuals; p = 0.009), syndromic scoliosis (from 0.7 (0.3 to 0.9) to 1.7 (1.2 to 2.4) per 100,000 individuals; p = 0.044), Scheuermann's kyphosis (SK) (from 0.2 (0 to 0.7) to 1.2 (1.1 to 1.3) per 100,000 individuals; p = 0.001), and scoliosis with intraspinal abnormalities (from 0.04 (0 to 0.08) to 0.6 (0.5 to 0.8) per 100,000 individuals; p = 0.008) across the study period. There was an increase in mean number of posterior spinal fusions performed each year from mean 84.5 (51 to 108) in 2005 to 2008 to 182.5 (170 to 210) in 2015 to 2018 (p < 0.001) and a reduction in mean number of growing rod procedures from 45.5 (18 to 66) in 2005 to 2008 to 16.8 (11 to 24) in 2015 to 2018 (p = 0.046).

Conclusion

The incidence of patients with spinal deformity undergoing surgery increased from 2005 to 2018. This was largely attributable to an increase in surgical patients with adolescent idiopathic scoliosis. Paediatric spinal deformity was increasingly treated by posterior spinal fusion, coinciding with a decrease in the number of growing rod procedures. These results can be used to plan paediatric spinal deformity services but also evaluate preventative strategies and research, including population screening.

Treatment of Severe Kyphoscoliosis in Children with Mucopolysaccharidosis Type I (Pfaundler-Hurler Syndrome) Using the Growing Rod Technique: A Case Series with Mid-Term Results

BACKGROUND

Patients with mucopolysaccharidosis type I (MPS I) have a good life expectancy due to early therapeutic options, such as stem cell therapy. Stem cell therapy can prevent the progression of some skeletal malformations. In contrast, the progression of thoracolumbar kyphoscoliosis, genua vara, and hip dysplasia cannot be influenced. We present 3 cases of children with MPS I with thoracolumbar kyphosis/kyphoscoliosis treated with a growing rod system.

CASE DESCRIPTION

The medical records and radiologic imaging of 3 children with a diagnosis of MPS I and kyphosis/kyphoscoliosis of the lumbar spine treated between 2007 and 2019 were retrospectively analyzed. Two children presented with a kyphoscoliosis, and 1 child had a combination of severe anterolisthesis and kyphoscoliosis. Surgery to correct the kyphosis and dorsal stabilization was performed in all patients after exhausted conservative treatment. There were no neurologic complications. Postoperative treatment and aftercare included a corset for 4 months and physical therapy. In all 3 patients, distraction surgery of the lumbar stabilization was done twice at a mean interval of 1 year.

CONCLUSIONS

If conservative treatment fails and surgery is necessary, an individual approach is needed. Dorsal stabilization with pedicle screws using a growing rod technique is an option for the correction of thoracolumbar/lumbar kyphosis in children with MPS I. However, fusion should be prevented initially or should be kept as short as possible. We achieved acceptable correction of the spinal deformity using the growing rod technique. Finally, surgery with correction and fusion is necessary after exhausted correction potential.

Surgical Management of Spinal Disorders in People with Mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are a group of inherited, multisystem, lysosomal storage disorders involving specific lysosomal enzyme deficiencies that result in the accumulation of glycosaminoglycans (GAG) secondary to insufficient degradation within cell lysosomes. GAG accumulation affects both primary bone formation and secondary bone growth, resulting in growth impairment. Typical spinal manifestations in MPS are atlantoaxial instability, thoracolumbar kyphosis/scoliosis, and cervical/lumbar spinal canal stenosis. Spinal disorders and their severity depend on the MPS type and may be related to disease activity. Enzyme replacement therapy or hematopoietic stem cell transplantation has advantages regarding soft tissues; however, these therapeutic modalities are not effective for bone or cartilage and MPS-related bone deformity including the spine. Because spinal disorders show the most serious deterioration among patients with MPS, spinal surgeries are required although they are challenging and associated with high anesthesia-related risks. The aim of this review article is to provide the current comprehensive knowledge of representative spinal disease in MPS and its surgical management, including the related pathology, symptoms, and examinations.

Treatment of thoracolumbar kyphosis in patients with mucopolysaccharidosis type I: results of an international consensus procedure

Background

In all patients with mucopolysaccharidosis type I (MPS I), skeletal disease (dysostosis multiplex) is a prominent, debilitating, condition related complication that may impact strongly on activities of daily living. Unfortunately, it is not alleviated by treatment with hematopoietic cell transplantation (HCT) or enzyme replacement therapy (ERT). Although early kyphosis is one of the key features of dysostosis multiplex, there is no international consensus on the optimal management. Therefore, an international consensus procedure was organized with the aim to develop the first clinical practice guideline for the management of thoracolumbar kyphosis in MPS I patients.

Methods

A literature review was conducted to identify all available information about kyphosis and related surgery in MPS I patients. Subsequently, a modified Delphi procedure was used to develop consensus statements. The expert panel included 10 spinal orthopedic surgeons, 6 pediatricians and 3 physiotherapists, all experienced in MPS I. The procedure consisted of 2 written rounds, a face-to-face meeting and a final written round. The first 2 rounds contained case histories, general questions and draft statements. During the face-to-face meeting consensus statements were developed. In the final round, the panel had the opportunity to anonymously express their opinion about the proposed statements.

Results

Eighteen case series and case reports were retrieved from literature reporting on different surgical approaches and timing of thoracolumbar kyphosis surgery in MPS I. During the face-to-face meeting 16 statements were discussed and revised. Consensus was reached on all statements.

Conclusion

This international consensus procedure resulted in the first clinical practice guideline for the management of thoracolumbar kyphosis in MPS I patients, focusing on the goals and timing of surgery, as well as the optimal surgical approach, the utility of bracing and required additional assessments (e.g. radiographs). Most importantly, it was concluded that the decision for surgery depends not only on the kyphotic angle, but also on additional factors such as the progression of the deformity and its flexibility, the presence of symptoms, growth potential and comorbidities. The eventual goal of treatment is the maintenance or improvement of quality of life. Further international collaborative research related to long-term outcome of kyphosis surgery in MPS I is essential as prognostic information is lacking.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-0997-5) contains supplementary material, which is available to authorized users.

Mucopolysaccharidoses: overview of neuroimaging manifestations

The mucopolysaccharidoses are a heterogeneous group of inherited lysosomal storage disorders, characterized by the accumulation of undegraded glycosaminoglycans in various organs, leading to tissue damage. Mucopolysaccharidoses include eight individual disorders (IS [Scheie syndrome], IH [Hurler syndrome], II, III, IV, VI, VII and IX). They have autosomal-recessive transmission with the exception of mucopolysaccharidosis II, which is X-linked. Each individual disorder has a wide spectrum of phenotypic variation, depending on the specific mutation, from very mild to very severe. The skeletal and central nervous systems are particularly affected. The typical clinical presentation includes organomegaly, dysostosis multiplex with short trunk dwarfism, mental retardation and developmental delay. In this article, we review the neuroimaging manifestations of the different types of mucopolysaccharidoses including the dysostosis multiplex of the skull and spine as well as the various central nervous system complications. These include white matter injury, enlargement of the perivascular spaces, hydrocephalus, brain atrophy, characteristic enlargement of the subarachnoid spaces as well as compressive myelopathy. The correlation between several of the neuroimaging features and disease severity remains controversial, without well-established imaging biomarkers at this time. Imaging has, however, a crucial role in monitoring disease progression, in particular craniocervical junction stenosis, cord compression and hydrocephalus, because this allows for timely intervention before permanent damage occurs.

Surgical Management of Thoracolumbar Kyphosis in Patients With Mucopolysaccharidosis: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the indications and outcomes for surgical treatment of thoracolumbar kyphosis in patients with mucopolysaccharidoses (MPS) to define future studies.

SUMMARY OF BACKGROUND DATA

Improvements in the medical treatment of MPS have increased lifespan and improved quality of life for many patients, but with no effect on thoracolumbar kyphosis. A greater number of these challenging patients may now be considered spinal surgical candidates.

METHODS

In accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a PubMed database search was conducted using relevant keywords to identify articles describing MPS patients with thoracolumbar kyphosis treated surgically. Information was collected regarding demographics, indications for surgery, surgical details and outcomes.

RESULTS

Sixteen articles describing 58 patients were included for review. The median age at surgery was 7 years (range 2.4-65 years) and median follow up was 3.7 years (range 7 weeks-10.3 years). The most commonly reported surgical indication was progression of deformity in 39/58 patients (67%). Preoperative neurological compromise was reported in 7/58 (12%) patients and resolved completely postoperatively in all pediatric patients. Three pediatric patients had died before final follow up. Postoperative paraplegia was reported in 2/51 patients who were neurologically intact preoperatively. Additional significant perioperative medical complications were reported in nine patients.

CONCLUSION

Thoracolumbar spinal surgery is most commonly performed in MPS I. Preoperative neurological compromise associated with thoracolumbar kyphosis was reported only in MPS IV and VI, where it was associated with factors other than the degree of kyphosis. Perioperative complications are common, may be catastrophic and relate to the complexity of the MPS condition. The indications for thoracolumbar kyphosis surgery in other conditions of short stature cannot be extrapolated to MPS patients.

LEVEL OF EVIDENCE

4.

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.

Dwarf with dual spinal kyphotic deformity at the cervical and dorsal spine unassociated with odontoid hypoplasia: Surgical management

Morquio's syndrome is associated with systemic skeletal hypoplasia leading to generalized skeletal deformation. The hypoplasia of odontoid process is frequent association, which is responsible for atlantoaxial dislocation causing compressive myelopathy. However, development of sub-axial cervical kyphotic deformity unassociated with odontoid hypoplasia is extremely rare, and coexistence of dorsal kyphotic deformity is not reported in the western literature till date and represents first case. Current case is 16-year-old boy, who presented with severe kyphotic deformity of cervical spine with spastic quadriparesis. Interestingly, he also had additional asymptomatic kyphotic deformity of dorsal spine; however, odontoid proves hypoplasia was not observed. He was only symptomatic for cervical compression, accordingly surgery was planned. The patient was planned for correction of cervical kyphotic deformity under general anesthesia, underwent fourth cervical corpectomy with resection of posterior longitudinal ligament and fusion with autologous bone graft derived from right fibula, which was refashioned approximating to the width of the corpectomy size after harvesting and fixed between C3 and C5 vertebral bodies and further secured with anterior cervical plating. He tolerated surgical procedure well with improvement in power with significant reduction in spasticity. Postoperative X-ray, cervical spine revealed complete correction of kyphotic deformity cervical spine. At follow-up 6 months following surgery, he is doing well. Successful surgical correction of symptomatic cervical kyphotic deformity can be achieved utilizing anterior cervical corpectomy, autologous fibular bone graft, and anterior cervical plating.

Pathogenesis and treatment of spine disease in the mucopolysaccharidoses

The mucopolysaccharidoses (MPS) are a family of lysosomal storage disorders characterized by deficient activity of enzymes that degrade glycosaminoglycans (GAGs). Skeletal disease is common in MPS patients, with the severity varying both within and between subtypes. Within the spectrum of skeletal disease, spinal manifestations are particularly prevalent. Developmental and degenerative abnormalities affecting the substructures of the spine can result in compression of the spinal cord and associated neural elements. Resulting neurological complications, including pain and paralysis, significantly reduce patient quality of life and life expectancy. Systemic therapies for MPS, such as hematopoietic stem cell transplantation and enzyme replacement therapy, have shown limited efficacy for improving spinal manifestations in patients and animal models. Therefore, there is a pressing need for new therapeutic approaches that specifically target this debilitating aspect of the disease. In this review, we examine how pathological abnormalities affecting the key substructures of the spine - the discs, vertebrae, odontoid process and dura - contribute to the progression of spinal deformity and symptomatic compression of neural elements. Specifically, we review current understanding of the underlying pathophysiology of spine disease in MPS, how the tissues of the spine respond to current clinical and experimental treatments, and discuss future strategies for improving the efficacy of these treatments.