Myelography in achondroplasia: value of a lateral C1-2 puncture and non-ionic, water-soluble contrast medium

Reoperation for spinal restenosis in achondroplasia

The characteristics of spinal restenosis in achondroplasia and its treatment are evaluated in this study. Radiologic and surgical findings were correlated to establish the causes of achondroplastic spinal restenosis and the benefits of its therapy. Eight patients (five men, three women) with spinal restenotic complications of achondroplasia were studied. The most common neurological sign of recurrent stenosis was impaired motor function. The mean interval between the most recent surgeries was 8.2 years (9.5 years for surgeries at the same levels). The most common causes of recurrent stenosis were facet hypertrophy and disk disease. The complications were a dural tear and cerebellar hemorrhage in one patient and transient neurological deterioration in another. One patient died after operation. Restenosis can occur many years after original decompression in the achondroplastic spine, and repeated operation can successfully lessen pain and neurological symptoms in most patients.

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.

Anatomy of the lumbar spine in achondroplasia

The authors analyze the achondroplastic lumbar spine in the pre-puberal and post-puberal periods until adulthood by means of standard X-rays, CT scan, MRI, and myelography. The small spinal canal in achondroplasts must be considered the result of developmental and congenital conditions. Orthopaedic and surgical possibilities are reviewed with the goal of reducing to a minimum the developmental factors.

Thoracolumbosacral laminectomy in achondroplasia: long-term results in 22 patients

Neurologic problems caused by vertebral stenosis in the thoracolumbosacral (TLS) region are common in achondroplasia. Surgical decompression by means of laminectomy is recommended often, but its long-term results have not been assessed. We reviewed the clinical history of 22 achondroplastic patients who had at least one TLS laminectomy performed before 1981. Symptoms predated the first TLS laminectomy by a mean of 2.3 years (range 0.1-17 years). Preoperatively, 91% of patients had motor function impairment, 86% had sensory dysfunction, 86% had neurogenic claudication, 77% had radicular pain, 59% had symptomatic bladder dysfunction, and 32% had fecal incontinence. Only upper motor neurons were affected in 45%, only lower motor neurons in 27%, and both in 27%. Follow-up after the first TLS laminectomy averaged 8 years. Of the 20 patients who initially improved neurologically, 12 had functional improvement for more than 5 years. However, 11 of these 12 subsequently regressed and 10 had additional laminectomies. Long-term neurologic and functional improvement was associated with both a short duration of symptoms preoperatively and absence of cervical stenosis. Because of hypertrophic scarring, 9 patients developed compression at the site of the initial TLS laminectomy and required re-operation 6.4 years (range 1-11 years) later. We conclude that TLS laminectomy is an effective treatment for spinal stenosis if performed early in the course of the neurologic syndrome. However, some patients have, or later develop, compression adjacent to the myelographic site of stenosis, and some develop hypertrophic scarring at the site of initial decompression. We therefore suggest that the first TLS laminectomy extend (1) 3 levels cephalad to the myelographic block, (2) at least to S2, and (3) laterally at least to the facets.