Correction of late traumatic thoracic and thoracolumbar kyphotic spinal deformities using posteriorly placed intervertebral distraction cages.

OBJECTIVE: To assess the safety and stability of thoracic or thoracolumbar deformity correction from a solely posterior approach with placement of modular anterior cages and posterior segmental fixation in one operation. METHODS: Twenty-eight patients who failed brace trial for 6 months or longer were included in the series. All patients had progressive neurological deficit and/or deformity progression at time of operation. All patients underwent a single operation in the prone position. Segmental fixation was accompanied by anterior column reconstruction using modular cages avoiding nerve root sacrifice. Stackable cages were used for high thoracic deformity. Deformity, Cobb angle, visual analog pain score, and x-ray evaluation of fusion ensued for mean follow-up period of 31 months. RESULTS: Patients achieved a mean sagittal deformity correction of 13.3 degrees +/- 7.4 standard deviation. Improved or maintained American Spinal Injury Association scores were noted in all patients. The mean time of operation was 334 minutes +/- 85 standard deviation, or 6 to 7 hours. At a mean follow-up of 31 months (range, 12-36 mo), the following complications were noted: subsidence greater than 2.5 mm (n = 3), cage migration requiring revision (n = 1), brachial plexopathy from malpositioning (n = 1), and intraoperative cerebrospinal fluid leak managed via lumbar drain (n = 2). Plain and dynamic radiographic evidence of maintained deformity correction was noted in 27 patients. CONCLUSION: Delayed kyphotic deformity correction of the thoracolumbar spine is achieved via a posterior-only approach. At a mean follow-up period of 31 months, sagittal angles remained acceptable. Improved fusion criteria and patient numbers will be required to determine fusion and loss of correction rates over time.

Classification of posterior dynamic stabilization devices.

Numerous new posterior dynamic stabilization (PDS) devices have been developed for the treatment of disorders of the lumbar spine. In this report the authors provide a classification scheme for these devices and describe several clinical situations in which the instrumentation may be expected to play a role. By using this classification, the PDSs that are now available and those developed in the future can be uniformly categorized.

Dynamic intraspinous spacer technology for posterior stabilization: case-control study on the safety, sagittal angulation, and pain outcome at 1-year follow-up evaluation.

OBJECT: To assess the safety and efficacy of the DIAM implant, the authors compared the mean 12-month outcomes in patients who underwent lumbar surgery with DIAM placement and in those who underwent lumbar surgery only. METHODS: Of 62 patients who underwent simple lumbar surgery (laminectomy and/or microdiscectomy) in a 24-month period, 31 underwent concomitant surgical placement of a DIAM interspinous process spacer (33 devices total). Radiographic imaging, pain scores, and clinical assessments were obtained postoperatively to a mean of 12 months (range 8-25 months). Patients who did not undergo implantation of an interspinous process spacer (Group C) were compared with and stratified against patients who underwent placement of a DIAM implant (Group D). In Group D, no statistically significant differences were noted in anterior or posterior disc height when comparing patients pre- and postoperatively. Compared with Group C, a relative kyphosis of less than 2 degrees was noted on postoperative images obtained in Group D. No statistically significant differences in visual analog scale (VAS) pain scores or MacNab outcomes were noted between Groups C and D at a mean of 12 months of follow up. Complications in Group D included three intraoperative spinous process fractures and one infection. CONCLUSIONS: After simple lumbar surgery, the placement of a DIAM interspinous process spacer did not alter disc height or sagittal alignment at the mean 12-month follow-up interval. No adverse local or systemic reaction to the DIAM was noted. No difference in VAS or MacNab outcome scores was noted between the groups treated with or without the DIAM implants, particularly when the DIAM was used to alleviate low-back pain.

Anesthetic considerations in the treatment of cervical myelopathy.

BACKGROUND CONTEXT: The safe surgical treatment of patients with severe cervical spondylotic myelopathy involves a team approach incorporating special anesthetic considerations. This patient population is more vulnerable to perioperative complications. Advanced age, prolonged periods of immobility, multiple medical co-morbidities, and the risk of worsening neurologic injury mandate that the anesthesiologist pay special attention in the preoperative, induction, surgical, and recovery phases. PURPOSE: To review the literature regarding the anesthetic management of patients undergoing surgery for cervical spondylotic myelopathy. CONCLUSION: A basic understanding of the pathophysiology of cervical myelopathy as well as the nuances of the surgical treatment plan can help to ensure safe and effective patient management.

Vector analysis correlating bullet trajectory to outcome after civilian through-and-through gunshot wound to the head: using imaging cues to predict fatal outcome.

OBJECTIVE: We identify radiographic imaging similarities found on head computed tomographic (CT) scans of patients with through-and-through gunshot wounds to the head with fatal outcomes. METHODS: A retrospective analysis was conducted over an 18-month period from June 2001 through December 2002. Two hundred seventeen gunshot wound patients were evaluated. Exclusion criteria included any patient with cardiopulmonary injury and instability, airway compromise, or extracranial injuries affecting prognosis. Thirty-seven patients with isolated gunshot wounds to the head were included, 10 of which were fatal. Vital signs, examination results, Glasgow coma scale (GCS) score, intracranial pressure monitoring, surgical data, days in the intensive care unit, and CT scan appearance were collected. A Cartesian xyz coordinate system was created centered on the dorsum sella. Bullet pathways on CT scans were plotted and graphed onto a standardized magnetic resonance imaging scan. RESULTS: Ten patients progressed to brain death. GCS score and pupil irregularity were associated with fatal outcome (P < 0.0001). CT scans showed that brain shift was more common in survivors. Seventy percent of nonsurvivors had minimal brain shift. A tram-track sign on CT scans correlated with fatal outcome (P = 0.005). Vector analysis of nonsurvivors showed an area of the brain approximately 4 cm above the dorsum sella that, when penetrated through the midline, led to brain death (P = 0.0006). This zone was coined the zona fatalis. CONCLUSION: We confirm that GCS score and diabetes insipidus correlated with fatal outcome. In the setting of low-velocity gunshot wounds, fatal outcome and low GCS score were associated with a tram-track sign on CT scans. Bullet passage through a particular supra-dorsum sellar transventricular zone was associated with fatal outcome.

Reliability of three-dimensional fluoroscopy for detecting pedicle screw violations in the thoracic and lumbar spine.

OBJECTIVE: Thoracic and lumbar pedicle screws have become popular because of their biomechanical superiority over other methods of spinal fixation. However, the safety and efficacy of transpedicular screws depend on their proper placement. Recent advances in imaging have resulted in the ability to acquire three-dimensional (3-D) axial images of the spine during surgery, and this study was undertaken to assess the reliability of this technology to detect pedicle violations. METHODS: Pedicle screws were placed in six human cadaver spines from T1 to S1 using standard techniques. Intentional pedicle violations were created in 74 of 216 pedicles, and violations were graded on a four-point scale (range, 0-3). Radiographic images were then obtained using a conventional spiral computed tomographic scanner and the Siremobil Iso-C 3D (Siemens Medical Solutions, Erlangen, Germany) 3-D fluoroscopy unit. An independent neuroradiologist then graded pedicle violations as ascertained by the two imaging modalities. RESULTS: Using direct inspection of the pedicles as the "gold standard," the overall sensitivity and specificity for detecting pedicle violations were 0.716 and 0.789, respectively, with 3-D fluoroscopy. The overall sensitivity and specificity for detecting pedicle violations were 0.608 and 0.937, respectively, with conventional computed tomography. All Grade 2 pedicle violations were detected in the thoracic spine by both modalities, and all Grade 3 violations were detected by both modalities. CONCLUSION: Axial images obtained with 3-D fluoroscopy demonstrate a higher sensitivity but lower specificity than conventional computed tomographic scanning for assessing pedicle violations. By providing real-time intraoperative imaging, 3-D fluoroscopy may enhance the safety of thoracic transpedicular instrumentation.

Unusual presentations of cerebral solitary fibrous tumors: report of four cases.

OBJECTIVE AND IMPORTANCE: Four rare cases of central nervous system solitary fibrous tumors (C-SoFTs) are described. This tumor has not previously been reported in children or in deep cortical structures. Three of these tumors occurred in the posterior fossa. Only four cases in the posterior fossa have been described previously. Nine years after its debulking from the posterior fossa, one tumor disseminated to the spine, lung, and liver. Only one such aggressive C-SoFT has been described previously. CLINICAL PRESENTATION: A 7-year-old child had had 1 year of right-sided weakness at presentation. Magnetic resonance imaging scans revealed a left basal ganglia lesion. A 49-year-old woman and a 30-year-old man presented after experiencing headaches for months. Magnetic resonance imaging scans in these patients revealed a tumor in the fourth ventricle and right jugular foramen, respectively. A 55-year-old man had spinal, liver, and lung dissemination of a previous posterior fossa tumor at presentation. INTERVENTION AND TECHNIQUE: All four patients underwent craniotomy for resection or subtotal removal of the tumor. Intraoperative observations noted solid well-encapsulated tumors. Immunohistochemistry confirmed C-SoFTs in all four cases. CONCLUSION: C-SoFTs are rare central nervous system, typically dural-based, tumors. They frequently are overlooked in the differential diagnosis of solid central nervous system tumors. Our findings suggest that these tumors can occur at any age and in most locations, regardless of proximity to the meninges (basal ganglia and ventricle), suggesting that the cells of origin are not meningothelial, but rather the mesenchyme of the cerebral vasculature. T1- and T2-weighted magnetic resonance imaging was notable for areas of hypointensity and of hyperintensity best described as patchy or a ying-yang appearance in all cases. Delayed extracranial metastasis may be noted.

The acute cerebrovascular event: surgical and other interventional therapies.

Over the next decade, more early and aggressive treatments will become available for acute stroke. As EPs have been forced to push their skills and knowledge significantly further with the advent of time-sensitive interventions for myocardial ischemia, a similar sophistication will undoubtedly emerge in the management of acute stroke. Certain components of the neurological examination will likely assume a new significance and, as with the renewed focus on the nature of ST segment change on the ECG in ACS, there will be new attention to early imaging findings in stroke. Although it is unclear whether the balance of future advances in treatment will come from the world of neurosurgery, neurology, or interventional radiology, the EP is relatively assured to play a central role in their implementation.

Klüver-Bucy syndrome as a result of minor head trauma.

Klüver-Bucy syndrome (KBS) has been described as a disconnection of the temporal lobes from the remainder of the brain. Its presence in minor head trauma has not been previously reported. We therefore report what we believe to be the first case of KBS due to mild head trauma and unilateral injury to a temporal lobe.