Henry Wang

Cervicomedullary compression in young patients with achondroplasia: Value of comprehensive neurologic and respiratory evaluation

We studied prospectively 26 young patients with achondroplasia to test two hypotheses: that respiratory problems may be the result of occult spinal cord compression, and that achondroplastic patients with cord compression might have occult respiratory abnormalities. Respiratory abnormalities were present in 85%, the majority caused by a primary problem of the pulmonary system, such as small thoracic cage or obstructed airway. Three patients had hypoxemia, recurrent cyanotic spells, and episodes of respiratory distress explainable only by cervicomedullary cord compression; in each patient, respiratory problems were alleviated by decompressive surgery. Another six patients with cervicomedullary compression had, in addition, at least one primary pulmonary cause of respiratory problems. After decompressive surgery the respiratory problems improved in three and were unchanged in three. Reconstructed sagittal CT images proved the most sensitive technique for detecting craniocervical stenosis as a cause of cervicomedullary cord compression, although some degree of stenosis was present in nearly all of the patients.

Occult, bilateral anterior sacral and intrasacral meningeal and perineurial cysts: case report and review of the literature.

None of the more than 180 cases of anterior sacral meningocele reported in the past 150 years has been bilateral, and only two have been associated with occult intrasacral meningocele. We report a unique case of bilateral anterior sacral cysts, communicating with the subarachnoid space, associated with occult intrasacral meningeal and perineurial (Tarlovs) cysts, in an asymptomatic woman. The pertinent clinical and diagnostic imaging literature is reviewed.

Compression syndromes due to hypertrophic nerve roots in hereditary motor sensory neuropathy type I

Three patients with hereditary motor sensory neuropathy type I developed neurologic deficits attributable to hypertrophic nerve roots. Compression of the cervical spinal cord by enlarged nerve roots occurred in our index patient. Multilevel decompressive laminectomies relieved the myelopathy. An unrelated patient who had syncope precipitated by neck rotation had hypertrophied nerve roots that eroded into the transverse foramina in juxtaposition to the vertebral arteries. In a 3rd patient, compression of hypertrophied nerve roots within the the cal sac and neural foramina was associated with spinal claudication and radiculopathy, respectively.

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.

Surgical Management of Cervicomedullary Compression in Achondroplastic Patients

In this segment it will not be necessary to go over the clinical presentations and pre-operative evaluations that are an essential part of the management of achondroplastic patients. It is sufficient to say that the clinical presentations such as delayed motor milestones, hyperreflexia and clonus, multiparesis, respiratory insufficiency and/or apnea, and obstructive sleep apnea are sufficient enough to warrant investigations to exclude cervicomedullary compression. If present, the evidence already presented during this conference in terms of outcome would justify surgical intervention. We will concentrate on the surgical preparation and the actual surgical procedure for decompressing the cervicomedullary region.

The Subarachnoid Fluid Space in Achondroplastic Spinal Stenosis: The Surgical Implication

The tragic outcome of decompressive laminectomy in patients with achondroplastic spinal stenosis has been reported (1, 2, 3, 4). Our experience at the Johns Hopkins Medical Institutions supports the observations in the literature. The poor outcome is caused mainly by the extremely stenotic canal, which makes adequate decompression difficult (5, 6, 7, 8, 9, 10, 11). Furthermore, the degree and extent of the spinal stenosis were frequently not clearly delineated by conventional myelography. However, intrathecal enhanced CT provides not only superb bony detail but also delineation of the soft-tissue content of the spinal canal (12). The relationships between the spinal cord and its surrounding subarachnoid space are also well demonstrated. This paper reports the depth of the subarachnoid fluid space surrounding the spinal cord at the cervical and thoracic levels, measured from the intrathecal enhanced axial CT images of 11 adult achondroplastic patients. It describes a modified decompressive laminectomy technique devised by the authors (S.U.) that has been applied in over 20 cases of achondroplastic spinal stenosis. It has helped to prevent the infliction of undue trauma on the neural tissue during the surgical manoeuvers.

Iohexol cervical myelography in adult outpatients

The incidence of adverse reactions following standard film or screen cervical myelography with iohexol in 32 adult outpatients was reported, lohexol at a dose of 1,080–3,000 mg of iodine was administered via a lateral C1-C2 approach in 26 patients and via a lumbar route in 6 patients. All 32 patients underwent postmyelographic cervical spine computed tomography and were discharged after the procedure was completed. No adverse reactions occurred in 53.1% of patients. The most common adverse reaction was headache (31.3%); other minor adverse reactions included exacerbation of pre-existing pain (12.5%), neck stiffness (9.4%), and vomiting (6.3%). Good to excellent technical quality was seen on all myelograms and computed tomographic scans. Outpatient cervical myelography with iohexol appears to be a safe and cost-effective alternative to inpatient examination.