Isolated oculomotor nerve palsy after lumbar epidural steroid injection in a diabetic patient.

BACKGROUND: In patients with diabetes mellitus, epidural steroid injections (ESI) have been noted to cause significant elevation of blood glucose levels, typically lasting 1-3 days. Here, we describe a previously unreported complication of a diabetic third nerve palsy associated with an ESI. CASE DESCRIPTION: A 66-year-old man with a history of coronary artery disease, hypertension, and insulin-dependent diabetes mellitus presented with low back pain and left lower extremity radiculopathy. The lumbar magnetic resonance imaging (MRI) revealed mild spondylosis, most severe at the L4-5 level, accompanied by a broad based disc protrusion resulting in mild central and moderate biforaminal stenosis. The patient underwent a left-sided L4-L5 transforaminal ESI resulting in transient elevation of his blood glucose levels. On post-procedure day 2, he developed a frontal headache and a complete right third nerve palsy with partial pupillary involvement. The MRI and MR angiography (MRA) of the brain revealed no compressive lesions or oculomotor abnormalities. Ophthalmoplegia and pupillary dysfunction resolved spontaneously over 4 months. CONCLUSIONS: Although rare, a history of a recent ESI should be considered as the etiology of an isolated oculomotor palsy in diabetic patients.

Spinal cord intramedullary pressure in thoracic kyphotic deformity: a cadaveric study.

STUDY DESIGN: In vitro cadaveric study of thoracic spinal cord intramedullary pressure (IMP) in kyphotic deformity. OBJECTIVE: To define the relationship between thoracic spinal kyphotic deformity and spinal cord IMP. SUMMARY OF BACKGROUND DATA: Previous studies of asymptomatic volunteers have revealed that there is wide variation in regional sagittal neutral upright thoracic spinal alignment with "normal" thoracic T4-T12 kyphosis ranging up to approximately +69° for 98.5% of the asymptomatic adult population. We sought to determine whether IMP changes in response to increasing thoracic kyphosis. METHODS: In 8 fresh-frozen cadavers, a progressive kyphotic deformity was created. Cadavers were positioned sitting with physiological thoracic kyphosis, head stabilized using a skull clamp, and spine segmentally instrumented from occiput to L2. The T3-T4 ligamentum flavum was removed, dura opened, and 3 pressure sensors were advanced caudally to T4-T5, T7-T8, and T11-T12 within the cord parenchyma. A stepwise thoracic kyphotic deformity was then induced by sequentially releasing and retightening the skull clamp while distracting posterior short segment rods and closing anterior segmental osteotomies. After each step, fluoroscopic images and pressure measurements were obtained; the T4-T12 Cobb angle was measured. RESULTS: Minor IMP increases of 2 to 5 mm Hg were observed at 1 or more spinal cord levels in 1 of 8 cadavers when the Cobb angle was less than +51° and in 4 of 8 cadavers when the angle was more than +51° and less than +63°. For Cobb angles more than +51° and less than +63°, a statistically significant, minor increase in IMP was detected at the T7-T8 level only (P = 0.02). At Cobb angles exceeding +63°, ΔIMP progressively increased at 1 or more spinal cord levels in 8 of 8 cadavers. Cobb angles ranging from +63° to +149° resulted in statistically significant increases in IMP ranging to more than 50 mm Hg. ΔIMP did not correlate with segmental spinal canal diameter (stenosis). CONCLUSION: Thoracic kyphosis less than +51° resulted in no meaningful increase in IMP, whereas kyphosis measuring +51° to +63° resulted in minor increases in IMP. After the thoracic kyphosis exceeded +63°, IMP increased significantly. ΔIMP with spinal alignment may help explain the wide range of "normal" thoracic neutral upright sagittal alignment in studies of asymptomatic adult individuals and may help further define thoracic kyphotic deformity.

Laminectomy, durotomy, and piotomy effects on spinal cord intramedullary pressure in severe cervical and thoracic kyphotic deformity: a cadaveric study.

OBJECT: Previous studies have shown that cervical and thoracic kyphotic deformity increases spinal cord intramedullary pressure (IMP). Using a cadaveric model, the authors investigated whether posterior decompression can adequately decrease elevated IMP in severe cervical and thoracic kyphotic deformities. METHODS: Using an established cadaveric model, a kyphotic deformity was created in 16 fresh human cadavers (8 cervical and 8 thoracic). A single-level rostral laminotomy and durotomy were performed to place intraparenchymal pressure monitors in the spinal cord at C-2, C4-5, and C-7 in the cervical study group and at T4-5, T7-8, and T11-12 in the thoracic study group. Intramedullary pressure was recorded at maximal kyphosis. Posterior laminar, dural, and pial decompressions were performed while IMP was monitored. In 2 additional cadavers (1 cervical and 1 thoracic), a kyphotic deformity was created and then corrected. RESULTS: The creation of the cervical and thoracic kyphotic deformities resulted in significant increases in IMP. The mean increase in cervical and thoracic IMP (change in IMP [ΔIMP]) for all monitored levels was 37.8 ± 7.9 and 46.4 ± 6.4 mm Hg, respectively. After laminectomies were performed, the mean cervical and thoracic IMP was reduced by 22.5% and 18.5%, respectively. After midsagittal durotomies were performed, the mean cervical and thoracic IMP was reduced by 62.8% and 69.9%, respectively. After midsagittal piotomies were performed, the mean cervical and thoracic IMP was reduced by 91.3% and 105.9%, respectively. In 2 cadavers in which a kyphotic deformity was created and then corrected, the ΔIMP increased with the creation of the deformity and returned to zero at all levels when the deformity was corrected. CONCLUSIONS: In this cadaveric study, laminar decompression reduced ΔIMP by approximately 15%-25%, while correction of the kyphotic deformity returned ΔIMP to zero. This study helps explain the pathophysiology of myelopathy in kyphotic deformity and the failure of laminectomy alone for cervical and thoracic kyphotic deformities with myelopathy. In addition, the study emphasizes the need for correction of deformity during operative treatment of kyphotic deformity, the need for maintaining adequate intraoperative blood pressure during operative treatment, and the higher risk of spinal cord injury associated with operative treatment of kyphotic deformity.