A case of mucopolysaccharidosis IV with lower leg paresis due to thoraco-lumbar kyphoscoliosis

Adjunct diagnostic value of radiological findings in mucopolysaccharidosis type IVa-related thoracic spinal abnormalities: a pilot study

Background

In patients with mucopolysaccharidosis (MPS), systematic assessment and management of cervical instability, cervicomedullary and thoracolumbar junction spinal stenosis and spinal cord compression averts or arrests irreversible neurological damage, improving outcomes. However, few studies have assessed thoracic spinal involvement in MPS IVa patients. We aimed to evaluate thoracic spinal abnormalities in MPS IVa patients and identify associated image manifestations by CT and MRI study.

Results

Data of patients diagnosed and/or treated for MPS IVa at MacKay Memorial Hospital from January 2010 to December 2020 were extracted from medical records and evaluated retrospectively. Computed tomography (CT), plain radiography and magnetic resonance imaging (MRI) findings of MPS IVa-related spinal abnormalities were reviewed. Spine CT and plain radiography findings of 12 patients (6 males and 6 females with median age 7.5 years, range 1–28 years) revealed two subtypes of spinal abnormalities: thoracic kyphosis apex around T2 (subtype 1, n = 8) and thoracic kyphosis apex around T5 (subtype 2, n = 4). Spine CT and plain radiography clearly identified various degrees of thoracic kyphosis with apex around T2 or T5 in MPS IVa patients. Square-shaped to mild central beaking in middle thoracic vertebral bodies was observed in subtype 1 patients, while greater degrees of central beaking in middle thoracic vertebral bodies was observed in subtype 2 patients.

Conclusions

Spine CT findings clearly identify new radiological findings of thoracic kyphosis apex around T2 or T5 in MPS IVa patients. The degrees of central beaking at middle thoracic vertebral bodies may be a critical factor associated with different image presentations of thoracic kyphosis.

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.

MRI findings of the cervical spine in patients with mucopolysaccharidosis type VI: relationship with neurological physical examination

AIM

To describe the magnetic resonance imaging (MRI) findings of the cervical spine of patients with mucopolysaccharidosis type VI (MPS VI) and correlate them with clinical manifestations.

MATERIALS AND METHODS

This is a cross-sectional study involving 12 patients with MPS VI. A limited neurological examination was undertaken in each patient including Tinel's test, assessment of muscle tone, and the evaluation of deep tendon reflexes. Additionally, each patient underwent cervical spine MRI to evaluate platybasia, odontoid dysplasia, periodontoid soft-tissue thickening, spinal canal stenosis, myelopathy, basilar invagination, platyspondyly, and reduction of nasopharyngeal airway.

RESULTS

Nine patients were male (75%). The average age was 12.5 (±3.5 years). Tinel's test was negative in all patients. No muscle tone abnormalities were observed. Approximately 48% of the tested reflexes were considered abnormal, 10 of which (8.3%) were pathological occurring in five different patients (41.6%). At MRI, all patients showed periodontoid soft-tissue thickening and cervical spinal stenosis; six showed spinal cord compression and two showed myelopathy. Odontoid hypoplasia and basilar invagination were observed in nine patients. All patients with cervical stenosis on MRI had abnormal reflexes; however, only two of the six patients with evidence of cord compression on MRI had abnormal reflexes on clinical examination.

CONCLUSIONS

The present study of 12 patients with MPS VI demonstrated that a normal neurological examination cannot confidently exclude potential cord compression in patients with this condition. MRI may aid in the timely identification of cervical spine abnormalities, and potentially play a role in lessening morbidity and mortality in patients with MPS.

Spine challenges in mucopolysaccharidosis

PURPOSE

Mucopolysaccharidosis (MPS) are rare inherited metabolic diseases, causing lysosomal storage of mucopolysaccharides; clinical presentation involves skeletal system and particularly the spine. Anomalies include developing kyphosis at thoracolumbar junction, that can causes nervous symptoms, and dens hypoplasia with associated atlantoaxial subluxation that can cause myelopathy. We present our experience in the treatment of spine pathology in MPS.

METHODS

Medical treatments of MPS seem to have little impact on spine disease: treatment of cervical instability often includes surgical decompression and stabilization, as in patient MPS1 that we present, while thoracic lumbar kyphosis is treated by bracing and, in severe cases, with surgery. Bracing is more effective in kyphosis under 40° Cobb. Our surgical cases with thoracic lumbar kyphosis over 40° Cobb, treatment include the first one ever described by only posterior approach with vertebrectomy in MPS and a case of lateral costo-transverse approach instrumented correction.

RESULTS

Surgical patients had no major complications after surgery and CT scan at follow-up showed complete fusion without loss of correction, even if in a cervical case we used an adult rigid instrumentation in a four year-and-six month-old girl (11 years follow-up) and in thoracic lumbar kyphosis case treated by vertebrectomy due to diminutive anatomy we positioned interbody cage in suboptimal position.

CONCLUSIONS

Bracing is a viable treatment strategy in thoracic lumbar kyphosis and can obtain good clinical results at medium terms follow-up even if kyphosis deformity remains in radiographs. Surgical treatment is effective in severe evolving cases both at cervical and thoracic lumbar level, main difficulties arose from unavailability of dedicated instrumentation in very young patient, as even smallest devices available are often too big.

Surgical Management of Progressive Thoracolumbar Kyphosis in Mucopolysaccharidosis: Is a Posterior-only Approach Safe and Effective?

BACKGROUND

According to the current literature, the recommended surgical treatment is circumferential spinal fusion, including both anterior and posterior procedures, for progressive thoracolumbar kyphosis in mucopolysaccharidosis (MPS). The purpose of this study was to report our experience with the posterior-only approach and instrumented fusion for MPS kyphosis.

METHODS

Six consecutive patients with MPS and thoracolumbar junctional kyphosis managed with the posterior-only approach were included. Demographic data, the type of MPS, medical comorbidities, and accompanying clinical manifestations were recorded. Measurements recorded on radiographs for the study included the presence of any coronal-plane deformity, fusion levels, changes in the local kyphosis angle (LKA), proximal and distal junctional kyphosis angles, and the apical vertebral wedge angle.

RESULTS

The average age at the time of surgery was 6.6 (range, 4 to 12) years. The average follow-up duration was 52.6 (range, 44 to 64) months. The mean preoperative LKA of 63.1±15.8 (range, 48 to 92) degrees decreased to a mean of 16.6±8.4 (range, 5 to 30) degrees immediately after surgery. At the latest follow-up, the mean LKA was 19.6±8.8 (range, 8 to 34) degrees. Apical vertebral listhesis was reduced in all patients with surgical correction. The average apical vertebral wedge angle of 15 (range, 11 to 19) degrees at the early postoperative period decreased to 4.6 (range, 2 to 7) degrees at the latest follow-up. Adjacent-segment problems occurred in 2 patients. There were no neurological complications or implant failures in any of the patients.

CONCLUSIONS

Posterior-only corrective techniques and instrumented fusion with pedicle screws for progressive thoracolumbar junctional kyphosis in MPS patients are safe and effective methods. Its results are comparable to those achieved with conventional circumferential fusion. However, patients should be monitored closely for adjacent-segment problems.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

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.

Spinal involvement in mucopolysaccharidoses: a review

BACKGROUND

Mucopolysaccharidoses (MPS) represent a group of inheritable lysosomal storage diseases caused by mutations in the genes coding for enzymes involved in catabolism of different glycosaminoglycans (GAGs). They are clinically heterogeneous multisystemic diseases, often involving the spine. Bony abnormalities of the spine included in the so-called dysostosis multiplex and GAG deposits in the dura mater and supporting ligaments can result in spinal cord compression, which can lead to compressive myelopathy. Spinal involvement is a major cause of morbidity and mortality in some MPS (e.g., MPS IVA, VI, and I), and early radiological diagnosis is critical in preventing or arresting neurological deterioration and loss of function.

DISCUSSION

Management of MPS, however, requires a multidisciplinary approach because of the multiorgan nature of the disease. Indeed in order to appreciate the relevance and nuances of each other's specialty, radiologists and clinicians need to have a background of common knowledge, rather than a merely compartmentalized point of view. In the interest of the management of spinal involvement in MPS, this review article aims on one hand to provide radiologists with important clinical knowledge and on the other hand to equip clinicians with relevant radiological semiotics.

Diagnostic evaluation, monitoring, and perioperative management of spinal cord compression in patients with Morquio syndrome

Mucopolysaccharidosis IVA is an autosomal recessive condition caused by mutations in the GALNS gene, which encodes N-acetylgalactosamine-6-sulfatase, also called galactosamine-6-sulfatase (GALNS). A reduction in or absence of effective GALNS leads to faulty catabolism of keratan sulfate and chondroitin-6-sulfate within the lysosome; their accumulation causes cell, tissue, and organ dysfunction. The connective tissue, cartilage, ligaments, and bone of patients with Morquio A syndrome are particularly affected. Patients with Morquio A syndrome are at high risk of neurological complications because of their skeletal abnormalities; many patients are in danger of cervical myelopathy due to odontoid hypoplasia and ligamentous laxity leading to atlantoaxial subluxation. The multisystemic involvement of patients with Morquio A syndrome requires treatment by multidisciplinary teams; not all members of these teams may be aware of the potential for subluxation and quadriparesis. A multinational, multidisciplinary panel of 10 skeletal dysplasia or Morquio A syndrome specialists convened in Miami, FL on December 7 and 8, 2012 to develop consensus recommendations for early identification and effective management of spinal cord compression, for anesthesia and surgical best practices, and for effectual cardiac and respiratory management in patients with Morquio A syndrome. The target audience for these recommendations includes any physician who may encounter a patient with Morquio A syndrome, however doctors who do not have access to the full spectrum of specialists and resources needed to support patients with Morquio A syndrome should attempt to refer patients to a center that does. Physicians who manage Morquio A syndrome or comorbid conditions within specialty centers should review these expert panel recommendations and fully understand the implications of spinal cord instability for their own practices.

Perioperative medullary complications in spinal and extra-spinal surgery in mucopolysaccharidosis: a case series of three patients

The mucopolysaccharidoses (MPS) are genetic lysosomal storage diseases. Peripheral bone dysplasia and spinal involvement are the predominant orthopedic damage. The risk of spinal cord compression due to stenosis of the craniocervical junction is well known in these patients, whereas the thoracolumbar kyphosis is often well tolerated over a long period of time. Thus, signs of spinal cord compression at this level occur later and more insidiously. The authors describe three cases of patients with thoracolumbar kyphosis who suffered from postoperative spinal cord compression in the absence of direct surgical trauma. Analysis of these cases and review of the literature helped identify causal factors resulting in spinal cord ischemia. The risk of perioperative spinal cord complications related to a thoracolumbar kyphosis must be discussed with patients with MPS and their families prior to any surgery, including extra-spinal procedures.

Surgical management of thoracolumbar kyphosis in mucopolysaccharidosis type 1 in a reference center

PURPOSE

Mucopolysaccharidosis (MPS) I is a rare autosomal recessive lysosomal storage disease. Thoracolumbar kyphosis is an early characteristic feature of the disease. Ossification failure in the anterosuperior quadrant of the vertebral body results in anterior dislocation. This study describes the surgical management of thoracolumbar kyphosis in MPS IH (Hurler syndrome) in a national reference center.

METHODS

Among 72 MPS I patients followed in our institution, we treated surgically 14 MPS IH patients with severe thoracolumbar kyphosis. The decision was made after documented deformity progression. Mean age at surgery was 8 (3.5-15) years. Sagittal imbalance of the trunk was constant. One patient underwent extended fusion for associated scoliosis. We retrospectively reviewed 13 patients who underwent selective circumferential fusion at the thoracolumbar level.

RESULTS

Average preoperative kyphosis was +57.5°(+30°; +90°). Surgical correction of the kyphosis was about 66 % and maintained at final follow-up. Fusion was obtained in all patients. Two patients required revision surgery consecutively to a previous posterior-only fusion, as a significant loss of correction occurred. One patient presented delayed neurologic deficit secondarily to cardiac embolism. One patient died postoperatively from cardiorespiratory failure.

CONCLUSION

Surgery is necessary when kyphosis is progressive despite orthopedic management, aggravating the multifactorial trunk imbalance. Regarding our experience, circumferential arthrodesis should be recommended to achieve stable correction. Surgical management requires a multidisciplinary approach due to multisystemic failure and neurological risks specific to metabolic disorders.

Brain and spinal MR imaging findings in mucopolysaccharidoses: a review

MPS represents a group of rare hereditary disorders characterized by multisystem involvement due to intralysosomal GAG accumulation. Among various tissues, both the central and peripheral nervous system are affected in almost all types of the disease. Thus, brain and spinal MR imaging are valuable tools for the assessment of neurologic involvement, and there is evidence that they might be reliable markers demonstrating disease severity and efficacy of treatment options currently used in patients with MPS. We aimed to review the most prominent MR imaging features of patients with MPS, paying attention to the physiopathologic mechanisms responsible for these alterations. Along with the description of neuroimaging findings, existing data in relation to their correlation with the severity of neurologic involvement is discussed, while another topic of great importance is the effect of various therapeutic regimens in the progression of brain and spinal MR imaging alterations. Finally, recent data concerning MR spectroscopy studies in MPS are also critically discussed.

A description of skeletal manifestation in adult case of morquio syndrome: radiographic and MRI appearance

We report on a rare case of Morquio syndrome, an autosomal recessive mucopolysaccharidosis including type IVA, a deficiency of N-acetylgalctosamine-6-sulfatase and type IVB a deficiency of β-galactosidase. A 43-year-old female patient affected by IVB Morquio syndrome underwent instrumental investigation. Conventional plain films of the entire spine, pelvis, chest and knees together with magnetic resonance imaging of the entire column, hip, knees, and ankles demonstrated the characteristics of skeletal changes of this disease. The main abnormalities were platyspondily and hypoplasia of the odontoid process, genua valga deformity and severe multiple degenerative changes of the hips, knees, and ankle joints. Radiographs and above all magnetic resonance imaging are crucial to provide substantial information about the gravity, evolution of the skeletal and joints changes, and the rehabilitation strategies to be followed.