Neurological considerations in achondroplasia

Surgical treatment of spinal stenosis in achondroplasia: Literature review comparing results in adults and paediatrics

BACKGROUND

This study aims to assess the quantity and quality of available literature on surgical treatment outcomes of spinal stenosis in adult and paediatric achondroplasia patients through a systematic review of literature and to investigate the suitability of conducting a meta-analysis on outcomes of surgical treatment.

METHODS

Online databases were searched according to PRISMA guidelines. No restrictions regarding study design, sample size, previous treatment, or publication date were implemented. The following terms: "Spinal stenosis", "Spinal Decompression", "Spinal fusion", each term separately combined with the term "Achondroplasia" were used. Quality of the included studies were assessed used the Modified Coleman method.

RESULTS

Five adult and four paediatric single-sample non-comparative studies were identified for inclusion (176 adult and 102 paediatric patients). Meta-analyses assessed the proportion of patients achieving full resolution of symptoms to be 0.51 (95% CI 0.00 to 1.00); the proportion of patients achieving full or partial resolution of symptoms to be 0.90 (95% CI 0.84 to 0.97); the proportion of procedures requiring re-operation to be 0.42 (95% CI 0.34 to 0.50; and the proportion of procedures involving dural tears to be 0.20 (95% CI 0.02 to 0.39). Statistical heterogeneity was very high for full resolution of symptoms and requirement for dural repair; and very low for other outcomes.

CONCLUSIONS

The available literature on this population and condition is sparse, highly heterogenous, and is generally of low quality limiting the value of meta-analysis. Overall, outcomes of surgical decompression of symptomatic spinal stenosis in achondroplasia patients show consistent degree of resolution of symptoms. Duration of symptoms prior to surgical treatment appears to play an important role in the overall outcome of treatment. Therefore, a delay in diagnosis and treatment can potentially be detrimental in achieving a better outcome.

Spinal stenosis surgery in pediatric patients with achondroplasia

OBJECT

Achondroplasia is a hereditary form of dwarfism caused by a defect in endochondral bone formation, resulting in skeletal abnormalities including short stature, shortened limb bones, macrocephaly, and small vertebral bodies. In the pediatric population, symptomatic spinal stenosis occurs at all spinal levels due to the abnormally narrow bone canal. In this study, clinical outcomes were assessed in children with achondroplasia after spinal canal decompression.

METHODS

A retrospective review was conducted involving pediatric patients with heterozygous achondroplasia and symptomatic stenosis after decompressive procedures at the authors' institution within a 9-year period. Measured outcomes included resolution of symptoms, need for repeated surgery, presence of fusion, development of deformity, and complications. Forty-four pediatric patients underwent a total of 60 decompressive procedures. The average patient age at surgery was 12.7 years (range 5-21 years). Forty-nine operations were performed for initial treatment of stenosis, and 11 were performed as revision surgeries on previously operated levels. A large proportion of patients (> 60%) required additional cervicomedullary decompressions, most often preceding the symptoms of spinal stenosis. Of the initial procedures, decompression locations included 32 thoracolumbar (65%), 10 lumbar (20%), four cervical (8%), two cervicothoracic (4%), and one thoracic (2%). Forty-three of the decompressive procedures (72%) included spinal fusion procedures. Of the 11 revisions, five were fusion procedures for progressive deformity at levels previously decompressed but not fused (all thoracolumbar), five were for decompressions of symptomatic junctional stenosis with extension of fusion, and one was for repeated decompression at the same level due to recurrence of symptomatic stenosis.

CONCLUSIONS

Decompression of the spinal canal in pediatric patients with achondroplasia can be accomplished safely with significant clinical benefit. Patients with a history of cervicomedullary compression may be at an increased risk of developing symptomatic stenosis prior to adolescence. Fusion procedures are recommended in patients with a large decompression overlying a thoracolumbar kyphosis to avoid progressive postoperative deformity.

Medical complications of achondroplasia: a multicentre patient review

Achondroplasia is the most prevalent chondrodysplasia and numerous authors have documented the varied social and medical complications that may compromise a full and productive life. Complications include cervicomedullary compression, spinal stenosis, restrictive and obstructive lung disease, otitis media, and tibial bowing, among others. These known complications have led to recommendations for the anticipatory management of such patients. There are relatively few data on the actual rates and timing of these problems. This paper reports data on the rates and age of occurrence of several of these complications based on a review of recorded chart information of 193 patients ascertained from several well established genetic centres with a known interest in the chondrodysplasias. The length of follow up varied and the rates of occurrence at specific age intervals were used to estimate the cumulative percentage affected for each complication. The report includes information on otitis media, ventilation tubes, hearing loss, tonsillectomy, speech problems, tibial bowing and osteotomy, ventricular shunting, apnoea, cervicomedullary decompression, and neurological signs attributable to spinal stenosis.

Total craniospinal decompression in achondroplastic stenosis

We describe our experience with total craniospinal decompression along the entire neuraxis, extending from the brain stem to the cauda equina, in seven patients with achondroplasia. These patients presented with clinically significant compression at multiple levels. In these patients, there were focal areas of complete myelographic block, typically at the cervicothoracic or thoracolumbar junction, as well as diffuse narrowing of the entire spinal subarachnoid space. In some, there were further complications of basilar impression, Arnold-Chiari malformation, or syringomyelia. Total craniospinal decompression was completed in either one or two stages. Only a small minority of our patients with achondroplasia had critical stenosis over this many levels, requiring total craniospinal decompression. However, with proper preparation and technique, we found that patients can tolerate even such an extensive decompressive procedure and benefit from surgery without suffering postoperative spinal instability.