Video fluoroscopic analysis of the effects of three commonly-prescribed off-the-shelf orthoses on vertebral motion.

STUDY DESIGN: Fluoroscopic assessment of the effects of commercially available spinal orthotics on lumbar vertebral motion as subjects performed flexion and extension maneuvers. OBJECTIVE: To quantitate the effects of 3 commonly available, off-the-shelf, soft, and semirigid spinal orthoses on lumbar spinal motion. SUMMARY OF BACKGROUND DATA: Commercially available soft and semirigid orthoses are widely prescribed for patients with low back pain and, at times, following surgery. Despite this use, surprisingly little is known about the magnitude of their effects on lumbar vertebral motion. METHODS: Ten subjects (6 men and 4 women) with an average age of 27.0 +/- 5.3 years, underwent videofluoroscopic imaging as they performed a full flexion/extension cycle. Assessments, during which the subjects were unbraced or wearing either a soft lumbrosacral orthosis (LSO), a semirigid LSO, or a semirigid thoracolumbrosacral orthosis (TLSO) were performed in random order. Images were obtained at a rate of 3.75 Hz and digitally processed to determine the sagittal rotation of the L3-L5 vertebral bodies. RESULTS: Each of the braces produced a statistically significant reduction in overall lumbar motion during the flexion maneuver (P = 0.007) but none had a detectable effect during extension. Relative effectiveness varied by vertebral level. At the L3-L4 level, only the TLSO had a statistically significant effect on intervertebral flexion movement (32%, P = 0.003). At the L4-L5 level all the orthoses were effective (and statistically indistinguishable) in their ability to reduce intervertebral flexion movements ranging from 48% for the semirigid TLSO to about 15% to 20% for the 2 LSOs. No effects were noted for any of the orthoses at the L5-S1 level. CONCLUSION: Commercially available soft and semirigid orthotics can have significant effects on lumbar vertebral body motion at the L3-L4 and L4-L5 levels.

Spinal extradural arteriovenous malformations with parenchymal drainage: venous drainage variability and implications in clinical manifestations.

OBJECT: Although nontraumatic spinal arteriovenous malformations and fistulas (AVMs and AVFs) restricted to the epidural space are rare, they can lead to significant neurological morbidity. Careful diagnostic imaging is essential to their detection and the delineation of the pathological anatomy. Aggressive endovascular and open operative treatment can provide arrest and reversal of neurological deficits. METHODS: The authors report on 6 cases of extradural AVMs/AVFs causing progressive myelopathy. Clinical findings, diagnostic evaluation, treatment, and outcome are discussed. Special consideration is given to the anatomy of the lesions and the operative techniques used to treat them. A review of the literature concerning extradural vascular malformations is also presented. RESULTS: All 6 cases of extradural AVMs had an extradural fistulous location with intradural medullary venous drainage. These cases illustrate progressive myelopathy through cord venous congestion (hypertension) that can be caused by an extradural nidus or fistula. In 4 cases, a large epidural lake was identified on angiography. At surgery, the epidural lake was obliterated and medullary drainage interrupted. All patients had stabilization of their neurological deficits and successful obliteration of the AVM/AVF was obtained. CONCLUSIONS: Extradural AVMs and AVFs are a poorly described entity with published clinical experience limited to sporadic case reports and small series. Although these lesions have a purely extradural location of arteriovenous shunting and early venous drainage, they can be responsible for acute and progressive neurological symptoms similar to those caused by their dural-based intradural counterparts. With careful imaging recognition of the pathological anatomy, surgical and endovascular techniques can be used for the treatment of extradural AVMs affording effective and durable obliteration with stabilization or reversal of neurological symptoms. Venous drainage directly correlates the pathologic mechanisms of presentation. Specific attention must be paid intraoperatively to the epidural lake common to both variants so that recurrence is avoided.

Intracranial electroencephalography with subdural grid electrodes: techniques, complications, and outcomes.

OBJECTIVE: Intracranial subdural grid monitoring is a useful diagnostic technique for surgical localization in patients with intractable partial epilepsy. The rationale for the present study was to assess the morbidity of intracranial recordings and the surgical outcomes. METHODS: We retrospectively reviewed the clinical data for 189 unique patients undergoing 198 intracranial subdural grid monitoring sessions between 1996 and 2004 at a tertiary epilepsy center. RESULTS: The mean age of patients undergoing monitoring was 28 +/- 14 years. An average of 63 +/- 23 electrodes were inserted. The mean duration of monitoring was 8 +/- 4 days. Localization of an epileptogenic zone occurred in 156 sessions (79%) resulting in 136 resections (69%). There were 13 major complications (6.6%), including five infections and six hematomas. Three patients (1.5%) developed permanent deficits related to implantation. Sixty-two (47%) of 136 patients undergoing resection were seizure-free after resection. An additional 38 patients (28%) had a significant reduction in seizures. The mean follow-up was 51 +/- 30 months. The duration of monitoring, bone flap replacement, number of electrodes, and perioperative corticosteroids were not associated with infection or complication. CONCLUSION: Subdural grid monitoring for identification an epileptogenic focus is high yield, revealing a focus in 79% of monitoring sessions. Complications rarely result in permanent morbidity (1.5%). Surgical outcome indicated that 74% of patients experienced a favorable reduction in seizure tendency.

Iatrogenic cerebellar implantation of a vestibular schwannoma. Case report.

Metastatic seeding or iatrogenic implantation of numerous types of primary central nervous system tumors, typically along cerebrospinal fluid pathways, is a frequently described albeit rare phenomenon and has never been reported in association with vestibular schwannoma (VS). The authors present a case of inadvertent surgical implantation of VS into the cerebellar hemisphere during resection of a recurrent VS in the cerebellopontine angle and internal auditory canal. A 42-year-old man presented with a 2.5-cm right VS that was removed without complication via a retrosigmoid approach. Routine imaging performed 5 years later revealed a 1.5-cm recurrence of the VS that was subsequently removed by reopening the retrosigmoid craniotomy. Five years later--10 years after initial presentation--follow-up imaging revealed a 1-cm recurrence of the VS and a separate 2.2-cm tumor in the inferior cerebellar parenchyma with surrounding edema. Both tumors were removed without complication by reopening the previous retrosigmoid craniotomy. Histological evaluation of these tumors revealed features typical of VS and similar to those of the tissue obtained from the two prior resections. Given the similarities among these tumors in pathological appearance and mitotic index, the presence of the intraparenchymal cerebellar schwannoma was probably due to intraoperative iatrogenic implantation.