Spinal stenosis frequent in children with multiple hereditary exostoses

Is total-body MRI useful as a screening tool to rule out malignant progression in patients with multiple osteochondromas? Results in a single-center cohort of 319 adult patients

PURPOSE

To evaluate the results of total-body (TB) MRI used as a screening tool for assessment or exclusion of malignant transformation in patients with hereditary multiple osteochondromas (HMO).

PATIENTS AND METHODS

In a single-institute cohort of MO patients, 366 TB-MRI examinations, including T1-weighted and STIR images, were performed for screening and follow-up purposes to rule out the malignant transformation, and retrospectively analyzed. In each patient, the presence and location of osteochondromas in the axial and appendicular bones were recorded. Forty-seven patients underwent a second TB surveillance in this period. STIR sequences were used to identify sites of increased signal intensity that could represent suspicious thickened cartilage caps or indeterminate reactive changes related to osteochondromas.

RESULTS

In 82% of patients, one or more OC locations were determined in one or more flat bones. In 366 exams, nine OC (2,5 %) with suspicious imaging features were identified. These proved to be peripheral chondrosarcomas after targeted MRI and resection were performed. All nine malignant lesions were in flat bones (pelvis 5, ribs 3, scapula 1). Three of these patients were 19 years of age. In 12 patients who had peripheral or intraosseous low-grade chondrosarcoma in their history, before their first TB-MRI, no new lesions were identified. Twenty-three additional TB-MRI exams, demonstrating focal high T2 signal intensity, also gave rise to performing additional targeted MRI. One OC of the distal femur was excised and appeared benign. No suspicious cartilage caps were depicted on the remaining 22 targeted MRI exams but instead increased T2 signal was clarified by reactive changes (frictional bursitis, soft tissue edema) in close relation with benign osteochondromas. No malignant lesions were found in 47 patients who had a second TB surveillance (mean interval between exams 3.2 years, range 2-5 years).

CONCLUSION

TB-MRI can identify malignant transformation of osteochondromas in HMO patients. All peripheral chondrosarcomas occurred in flat bones (ribs, scapula, pelvis) in our study. TB-MRI might assist in triage between higher risk patients with a high burden of OC, including the location of OC in main flat bones vs lower risk patients without OC of the flat bones.

Surgical tool entrapment in a young patient with recurrent lumbar spinal stenosis: a case report

Lumbar spinal stenosis (LSS) is a prevalent cause of leg and back pain. In the youth, LSS is not common and mainly results from hereditary musculoskeletal disorders. Moreover, spinal fusion is a surgical approach to the treatment of LSS. Entrapment of surgical tools due to breakage is a rare yet important phenomenon in such operations. Therefore, neurological sequelae of these events need to be explored. The case was a 24-year-old male complaining of local back pain. Initially, he was diagnosed with LSS at L4 and L5. After the fusion of the vertebrae by the posterior spinal fusion (PSF) method, the patient's pain was resolved. However, the subject complained of worsening local back pain limiting his ability to do routine tasks. A few years later, radiographical evaluations indicated the possible presence of a surgical tool that could not be removed via surgery. During a third operation, the object was removed, and the patient's symptoms recovered. Immediate removal of entrapped surgical objects is necessary due to risks associated with migration and central nervous system damage. Comparing our results to other similar reports, we conclude that in cases of foreign object entrapment, neurological sequelae may be nonexistent or progressively worsen. Also, sequelae emerge either soon after the operation or emerge later. This complicates the diagnosis of such events and the decision of whether to subject the patient to additional neurosurgical operations to remove the tool. These variations may be observed due to the moving of the entrapped tool. Follow-up of neurological sequelae in spinal surgery patients is recommended.

Surgical outcomes of spinal osteochondroma in children: A multicentre observational study

BACKGROUND

Spinal osteochondroma (or exostosis) is a rare benign tumour whose clinical manifestations are delayed due to their slow growth and location. Few studies have addressed the characteristics and the diagnostic and therapeutic peculiarities of spinal osteochondroma in children. The objective of this multicentre observational study was to assess the outcomes of a cohort of children after surgery for spinal osteochondroma.

HYPOTHESIS

Surgical excision of spinal osteochondroma in children is not followed by complications or recurrences.

MATERIAL AND METHODS

We included consecutive children who had surgery between 2010 and 2018 at any of eight participating centres to remove spinal osteochondromas. The cause, clinical manifestations, and location of the lesions were collected. The surgical outcomes were evaluated after at least 2 years' follow-up.

RESULTS

We identified 22 patients who had surgery to remove 26 spinal osteochondromas at a mean age of 12.8±2.6 years. Among them, 7 had a solitary osteochondroma (SO group) and 15 had hereditary multiple osteochondromas (HMO group). At diagnosis, 72% of patients had clinical signs (spinal pain, n=4; one or more lumps, n=5; and neurological manifestations, n=3). In the HMO group, the diagnosis was made during routine MRI screening for tumours involving the spinal canal. Most osteochondromas involved the cervical spine (n=13), with no difference between the two groups (p=0.9). The lamina was the most common location but 54% of the tumours were growing within the canal (92% in the HMO group). After a mean follow-up of 5.2±4.4 years, no patients had experienced any recurrences or complications related to the disease or treatment.

DISCUSSION

Surgical excision of spinal osteochondromas in children is effective, with no medium-term recurrences. Our results also confirm the low peri-operative morbidity, even when the canal is involved, and the absence of any effect at last follow-up on spinal alignment. All patients with neurological manifestations at diagnosis made a full recovery.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

The Incidence of Vertebral Exostoses in Multiple Hereditary Exostoses and Recommendations for Spinal Screening

BACKGROUND

Multiple hereditary exostoses (MHE) lead to the development of pedunculated or sessile osteocartilaginous lesions. Vertebral involvement occurs in MHE and encroaching intracanal exostoses can result in devastating consequences. Magnetic resonance imaging (MRI) of the entire spine has been used to screen for vertebral exostoses to detect high-risk patients. The primary purpose of this investigation is to determine the incidence of vertebral and encroaching intracanal exostoses in patients with MHE. A secondary purpose is to determine if pelvis and rib exostoses serve as "harbinger" lesions of vertebral involvement in MHE.

METHODS

A retrospective chart review was performed on 39 patients (21 male and 18 female individuals) with MHE who underwent routine spinal screening with noncontrast entire spine MRI. The average age at screening was 12.3 years (range, 3 to 17 y). Screening was ordered consecutively on patients seen during the study period who were between ages 8 and 18 years or had complaints that could be related to encroaching intracanal exostoses.

RESULTS

The incidence of vertebral exostoses in this cohort of 39 patients with MHE was 28% (11 total). An encroaching intracanal exostosis was seen in 3 patients (2 cervical, 1 thoracic). Nonencroaching vertebral exostoses were discovered in 8 patients. Sufficient pelvis and rib imaging to determine the presence of pelvis and rib exostoses was available in 8 of those with vertebral exostoses and 19 of those with no vertebral exostoses on screening MRI. In this cohort, the sensitivity and specificity of the presence of both pelvis and rib exostoses for determining the presence of spinal involvement in MHE are 88% and 5%, respectively.

CONCLUSIONS

Based on the results of this cohort, vertebral exostoses are common in MHE, and screening MRI of the entire spine can be used to determine which patients need close observation. If a more selective screening protocol is utilized, an entire spine MRI could be obtained for patients who desire increased physical activity levels or for patients with both pelvis and rib exostoses. At a minimum, treating physicians should monitor patients with MHE closely for neurological symptoms and have a low threshold to obtain advanced spinal imaging.

LEVEL OF EVIDENCE

Level III-diagnostic.

Prospective spine at risk program for prevalence of intracanal spine lesions in pediatric hereditary multiple osteochondromas

STUDY DESIGN

Retrospective cohort study OBJECTIVES: To determine prevalence of hereditary multiple osteochondromas (HMO) and utility of MRI surveillance in a prospective Spine at Risk (SAR) program. Unidentified intraspinal exostoses in HMO can lead to neurologic injury in children during sedated procedures but no MRI guidelines exist. We sought to determine the prevalence and age of intraspinal exostoses from MRIs, and indications for MRI surveillance.

METHODS

Retrospective review was performed of pediatric HMO patients who underwent total spine MRIs at a single institution after a prospective SAR program was instituted. Charts were reviewed for MRI indication and findings, symptoms, surgery, and location of other exostoses. Fisher's exact test was used to compare categorical variables and T test to compare continuous variables. Predictive value of pelvic/rib exostoses was calculated for intraspinal lesions.

RESULTS

Forty-three patients with HMO underwent total spine MRIs with average age of 11.5 years. Fifteen (35%) patients had exostoses on vertebral column, eight (19%) had intra-canal spinal exostoses. Higher prevalence of spine lesions occurred in symptomatic patients than asymptomatic (any spinal lesion: 73% prevalence in symptomatic vs 22% in asymptomatic, p < 0.005; intra-canal spinal lesion: 46% vs 9%, p < 0.05). Only two of the 11 'symptomatic presentations' could be attributable to intracanal spinal exostoses. Only one intra-canal exostosis found on asymptomatic surveillance was treated surgically. Presence of pelvic or rib exostoses were not strongly predictive of intra-canal lesions (23% PPV, 85% NPV, 63% sensitivity, 51% specificity).

CONCLUSIONS

Even with the presence of intra-canal exostoses, true symptomatic lesions are rare. Rib and pelvic lesions were not predictive of intra-canal lesions in our population. We recommend obtaining MRIs at time of preoperative evaluation in asymptomatic children old enough to not need sedation, or in patients with true neurologic symptoms to prevent unnecessary sedation of younger children for surveillance MRI.

LEVEL OF EVIDENCE

III.

Understanding the Action of RARγ Agonists on Human Osteochondroma Explants

Osteochondromas are cartilage-capped growths located proximate to the physis that can cause skeletal deformities, pain, limited motion, and neurovascular impingement. Previous studies have demonstrated retinoic acid receptor gamma (RARγ) agonists to inhibit ectopic endochondral ossification, therefore we hypothesize that RARγ agonists can target on established osteochondromas. The purpose of this study was to examine the action of RARγ agonist in human osteochondromas. Osteochondroma specimens were obtained during surgery, subjected to explant culture and were treated with RARγ agonists or vehicles. Gene expression analysis confirmed the up-regulation of RARγ target genes in the explants treated with NRX 204647 and Palovarotene and revealed strong inhibition of cartilage matrix and increased extracellular matrix proteases gene expression. In addition, immunohistochemical staining for the neoepitope of protease-cleaved aggrecan indicated that RARγ agonist treatment stimulated cartilage matrix degradation. Interestingly, cell survival studies demonstrated that RARγ agonist treatment stimulated cell death. Moreover, RNA sequencing analysis indicates changes in multiple molecular pathways due to RARγ agonists treatment, showing similarly to human growth plate chondrocytes. Together, these findings suggest that RARγ agonist may exert anti-tumor function on osteochondromas by inhibiting matrix synthesis, promoting cartilage matrix degradation and stimulating cell death.

Spinal Screening MRI Trends in Patients with Multiple Hereditary Exostoses: National Survey

Background

Multiple hereditary exostoses (MHE) is a rare disease characterized by multiple osteochondromas. Osteochondromas growing into the spinal canal can produce devastating consequences, including permanent neurologic deficits and even death. Routine screening of the entire spinal canal with magnetic resonance imaging (MRI) is a controversial topic lacking a clear consensus or recommendation to guide decision-making. This study presents a case of an intracanal osteochondroma at C1 identified by routine screening and a survey describing current practices of MHE experts.

Methods

MHE experts were surveyed. Survey questions addressed multiple aspects of care, including the type of practice center, the volume of patients with MHE, and current screening practices.

Results

A total of 104 experts were contacted, with a total of 26 experts participating in the survey and 23 completing the entire survey. Seventy-two percent of respondents do not perform a routine MRI screen of the spine. For experts that routinely screen, screening is performed across a wide/variable age range (4-18 years).

Conclusion

Screening protocols for MHE patients to identify osteochondromas within the spinal canal has struggled to reach consensus due to the rarity of the disease. Recent literature provides conflicting advice for patients without neurological symptoms. Our study demonstrates that even experts who are leading the field demonstrate wide practice variability. Most respondents do not routinely perform screening spinal MRI. Due to the wide variability, a national guideline is needed to help guide physician and parental decision-making for patients with MHE. Our case illustrates the potential benefit of identifying an osteochondroma within the spinal canal at a location where further growth could have devastating neurological sequelae.

Hereditary Multiple Exostoses: Current Insights

Hereditary multiple exostoses (HME), also called hereditary multiple osteochondromas, is a rare genetic disorder characterized by multiple osteochondromas that grow near the growth plates of bones such as the ribs, pelvis, vertebrae and especially long bones. The disease presents with various clinical manifestations including chronic pain syndromes, restricted range of motion, limb deformity, short stature, scoliosis and neurovascular alteration. Malignant transformation of exostosis is rarely seen. The disease has no medical treatment and surgery is only recommended in symptomatic exostoses or in cases where a malignant transformation is suspected. HME is mainly caused by mutations and functional loss of the EXT1 and EXT2 genes which encode glycosyltransferases, an enzyme family involved in heparan sulfate (HS) synthesis. However, the peculiar molecular mechanism that leads to the structural changes of the cartilage and to osteochondroma formation is still being studied. Basic science studies have recently shown new insights about altering the molecular and cellular mechanism caused by HS deficiency. Pediatricians, geneticists and orthopedic surgeons play an important role in the study and treatment of this severe pathology. Despite the recent significant advances, we still need novel insights to better specify the role of HS in signal transduction. The purpose of this review was to analyze the most relevant aspects of HME from the literature review, give readers an important tool to understand its clinical features and metabolic-pathogenetic mechanism, and to identify an effective treatment method. We focused on the aspects of the disease related to clinical management and surgical treatment in order to give up-to-date information that could be useful for following best clinical practice.

Is Routine Spine MRI Necessary in Skeletally Immature Patients With MHE? Identifying Patients at Risk for Spinal Osteochondromas

BACKGROUND

Multiple hereditary exostoses (MHE) is an autosomal dominant condition leading to development of osteochondromas throughout the body. Although long bones are most often affected, spine involvement may occur and usually requires advanced imaging for diagnosis. However, the high cost of detection, infrequent occurrence, and very low likelihood of spinal cord compression and neurological injury, create a management conundrum. The purpose of our investigation is to identify patients at greatest risk for spinal lesions and refine indications for advanced imaging.

METHODS

All MHE patients in a 24-year period were retrospectively reviewed. Skeletally immature patients with advanced imaging of the spine were further evaluated. The demographic characteristics, family history, clinical presentation, past surgical history, tumor burden, and distribution of patients with spinal lesions were compared with those without.

RESULTS

In total, 227 MHE patients were identified and 21 underwent advanced spinal imaging. Spinal lesions were found in 8 of the 21 screened patients (38.1%, 3.5% overall), of which 4 were intracanal and 1 was symptomatic (4.8%, 0.4% overall). Only the symptomatic patient underwent excision of the spinal lesion. Patients with spinal lesions had higher tumor burden than those without (median, 28.5 vs. 19 locations; P=0.010). There was a significant association with rib (P=0.018) and pelvic (P=0.007) lesions, which may serve as "harbinger" lesions. The presence of both a rib and a pelvic lesion used as a screening tool for spinal lesions produces a sensitivity of 100% and specificity of 69%.

CONCLUSIONS

Symptomatic spinal involvement in children with MHE is rare and tends to occur in patients with higher tumor burden. We recommend limiting advanced spine imaging to children with neurological symptoms or with rib and pelvic "harbinger" lesions. Patients without these findings are unlikely to have spine involvement needing intervention. This approach offers an opportunity to avoid unnecessary testing and substantially reduce costs of diagnostic imaging.

LEVEL OF EVIDENCE

Level III.

The pathogenic roles of heparan sulfate deficiency in hereditary multiple exostoses

Heparan sulfate (HS) is an essential component of cell surface and matrix proteoglycans (HS-PGs) that include syndecans and perlecan. Because of their unique structural features, the HS chains are able to specifically interact with signaling proteins -including bone morphogenetic proteins (BMPs)- via their HS-binding domain, regulating protein availability, distribution and action on target cells. Hereditary Multiple Exostoses (HME) is a rare pediatric disorder linked to germline heterozygous loss-of-function mutations in EXT1 or EXT2 that encode Golgi-resident glycosyltransferases responsible for HS synthesis, resulting in a systemic HS deficiency. HME is characterized by cartilaginous/bony tumors -called osteochondromas or exostoses- that form within perichondrium in long bones, ribs and other elements. This review examines most recent studies in HME, framing them in the context of classic studies. New findings show that the spectrum of EXT mutations is larger than previously realized and the clinical complications of HME extend beyond the skeleton. Osteochondroma development requires a somatic "second hit" that would complement the germline EXT mutation to further decrease HS production and/levels at perichondrial sites of osteochondroma induction. Cellular studies have shown that the steep decreases in local HS levels: derange the normal homeostatic signaling pathways keeping perichondrium mesenchymal; cause excessive BMP signaling; and provoke ectopic chondrogenesis and osteochondroma formation. Data from HME mouse models have revealed that systemic treatment with a BMP signaling antagonist markedly reduces osteochondroma formation. In sum, recent studies have provided major new insights into the molecular and cellular pathogenesis of HME and the roles played by HS deficiency. These new insights have led to the first ever proof-of-principle demonstration that osteochondroma formation is a druggable process, paving the way toward the creation of a clinically-relevant treatment.

Pediatric spondylolysis/spinal stenosis and disc herniation: national trends in decompression and discectomy surgery evaluated through the Kids' Inpatient Database

PURPOSE

The purpose of this study is to describe national trends in spinal decompression without fusion and discectomy procedures in the US pediatric inpatient population.

METHODS

The Kids' Inpatient Database (KID) was queried for pediatric patients with primary diagnoses of spinal spondylolysis/stenosis or disc herniation and having undergone spinal decompression without fusion or discectomy over more than a decade (2000 to 2012). The primary (indirect) outcomes of interest were in-hospital complication rates, length of stay (LOS), total costs, and discharge dispositions.

RESULTS

A total of 7315 patients, comprised of pediatric spinal spondylolysis/stenosis (n = 287, 3.92%) and pediatric disc herniation (n = 7028, 96.1%) patients, were included in the study. During the years 2000 to 2012, diagnoses of pediatric spondylolysis/spinal stenosis increased from 61 to 90 diagnoses per 3-year period, while diagnoses of pediatric disc herniation decreased from 2133 to 1335 diagnoses per 3-year period. Spinal decompression was associated with higher in-hospital complication rates (18.1 vs 5.3%, p < 0.0001), longer hospital stays (5 vs 1.69 days, p < 0.0001), higher mean total charges ($49,186 vs $19,057, p < 0.0001), and higher non-routine discharge rates (12.3 vs 2.5%, p < 0.0001) versus discectomy.

CONCLUSIONS

Spinal decompression is associated with longer hospital stays, more complications, higher costs, and more non-routine discharges when compared to discectomy. The data supports the disparate nature of these disease processes and elucidates basic clinical trends in uncommon spinal disorders affecting children.

Hereditary Multiple Exostoses: New Insights into Pathogenesis, Clinical Complications, and Potential Treatments

PURPOSE OF REVIEW

Hereditary multiple exostoses (HME) is a complex musculoskeletal pediatric disorder characterized by osteochondromas that form next to the growth plates of many skeletal elements, including long bones, ribs, and vertebrae. Due to its intricacies and unresolved issues, HME continues to pose major challenges to both clinicians and biomedical researchers. The purpose of this review is to describe and analyze recent advances in this field and point to possible targets and strategies for future biologically based therapeutic intervention.

RECENT FINDINGS

Most HME cases are linked to loss-of-function mutations in EXT1 or EXT2 that encode glycosyltransferases responsible for heparan sulfate (HS) synthesis, leading to HS deficiency. Recent genomic inquiries have extended those findings but have yet to provide a definitive genotype-phenotype correlation. Clinical studies emphasize that in addition to the well-known skeletal problems caused by osteochondromas, HME patients can experience, and suffer from, other symptoms and health complications such as chronic pain and nerve impingement. Laboratory work has produced novel insights into alterations in cellular and molecular mechanisms instigated by HS deficiency and subtending onset and growth of osteochondroma and how such changes could be targeted toward therapeutic ends. HME is a rare and orphan disease and, as such, is being studied only by a handful of clinical and basic investigators. Despite this limitation, significant advances have been made in the last few years, and the future bodes well for deciphering more thoroughly its pathogenesis and, in turn, identifying the most effective treatment for osteochondroma prevention.

Unsuspected osteochondroma-like outgrowths in the cranial base of Hereditary Multiple Exostoses patients and modeling and treatment with a BMP antagonist in mice

Hereditary Multiple Exostoses (HME) is a rare pediatric disorder caused by loss-of-function mutations in the genes encoding the heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. HME is characterized by formation of cartilaginous outgrowths-called osteochondromas- next to the growth plates of many axial and appendicular skeletal elements. Surprisingly, it is not known whether such tumors also form in endochondral elements of the craniofacial skeleton. Here, we carried out a retrospective analysis of cervical spine MRI and CT scans from 50 consecutive HME patients that included cranial skeletal images. Interestingly, nearly half of the patients displayed moderate defects or osteochondroma-like outgrowths in the cranial base and specifically in the clivus. In good correlation, osteochondromas developed in the cranial base of mutant Ext1f/f;Col2-CreER or Ext1f/f;Aggrecan-CreER mouse models of HME along the synchondrosis growth plates. Osteochondroma formation was preceded by phenotypic alteration of cells at the chondro-perichondrial boundary and was accompanied by ectopic expression of major cartilage matrix genes -collagen 2 and collagen X- within the growing ectopic masses. Because chondrogenesis requires bone morphogenetic protein (BMP) signaling, we asked whether osteochondroma formation could be blocked by a BMP signaling antagonist. Systemic administration with LDN-193189 effectively inhibited osteochondroma growth in conditional Ext1-mutant mice. In vitro studies with mouse embryo chondrogenic cells clarified the mechanisms of LDN-193189 action that turned out to include decreases in canonical BMP signaling pSMAD1/5/8 effectors but interestingly, concurrent increases in such anti-chondrogenic mechanisms as pERK1/2 and Chordin, Fgf9 and Fgf18 expression. Our study is the first to reveal that the cranial base can be affected in patients with HME and that osteochondroma formation is amenable to therapeutic drug intervention.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Management of nerve compression in multiple hereditary exostoses: a report of two cases and review of the literature

PURPOSE

Multiple hereditary exostoses (MHE) is a rare autosomal dominant condition that results in the growth of cartilage-capped prominences that often cause nerve compression and injury. Many patients suffer from continued and debilitating chronic pain which leads some to advocate avoiding surgical intervention in patients with multiple hereditary exostoses. We present a review of the literature as well as a case series at our institution in order to evaluate the role of surgery in multiple hereditary exostoses.

METHODS

We searched the literature for reports of patients with multiple hereditary exostoses undergoing surgery for nerve compression. We then reviewed the recent experience at our institution which revealed two patients with multiple hereditary exostoses.

RESULTS

Our literature search revealed that there have been several case series and retrospective analyses in the literature that assess the benefit of surgery in the case of nerve compression caused by exostoses. The majority of these reports are of solitary exostoses. Few reports expand on the role of surgery in patients with multiple hereditary exostoses suffering from nerve compressions secondary to bony overgrowth. A recent review of the experience at our institution revealed two patients with multiple hereditary exostoses who together underwent a total of four surgeries for treatment of peripheral nerve compression resulting in pain or weakness. Postoperative evaluation revealed improvement in pain and/or motor strength following each operation.

CONCLUSION

Based on our experience and literature review, we advocate that nerve compression in selected individuals with multiple hereditary exostoses that results in neurological injury should be considered for nerve decompression and resection of the offending exostosis.

Unusual case of hereditary multiple exostoses presenting with compressive myelopathy

A 15-year-old boy presented with progressive weakness of both lower limbs. He had classical clinical features suggestive of multiple hereditary exostoses (MHE). Imaging studies of the spine revealed osteochondromas at D7, D11 and L5 vertebrae. The tumour at D11 was encroaching into the spinal canal and causing cord compression. The patient underwent osteochondroma excision and posterior spinal stabilisation, following which there was complete neurological recovery by 3 months.