Intraoperative reduction of locked facets in the cervical spine by use of a modified interlaminar spreader: technical note.

OBJECTIVE: Facet dislocations commonly require intraoperative reduction after closed reduction with traction has failed. Reduction should be performed in a gradual, controlled fashion to prevent additional inadvertent spinal cord compromise. METHODS: We describe a new technique for safe and simple dorsal reduction of facet dislocations by use of a modified interlaminar spreader. This technique requires only minimal controlled manipulation of the spine. RESULTS: We have used this technique in 52 consecutive patients with no complications or failures related to its use in open reduction. This technique increases the stability of the cervical spine after reduction because it limits bone removal from the facet joints. CONCLUSION: This technique provides a feasible and reliable approach to open reduction of cervical facet dislocations via the posterior approach.

Surgical treatment for acute spinal cord injury study pilot study #2: evaluation of protocol for decompressive surgery within 8 hours of injury.

Acute spinal cord injury (SCI) is a major public health problem for which there is still only limited treatment available. The National Acute Spinal Cord Injury Study-2 (NASCIS-2) and -3 clinical trials demonstrated that the use of acute pharmacotherapy with methylprednisolone can attenuate the secondary injury cascade if administered within 8 hours of acute SCI. However, no trial has been performed to examine whether acute surgical decompressive procedures within this critical 8-hour time window can improve patients' neurological outcome. The purpose of the current prospective Surgical Treatment for Acute Spinal Cord Injury Study (STASCIS) pilot study was to determine the feasibility of obtaining a radiological diagnosis of spinal canal compromise of 25% or more and to perform spinal cord (C3-T1) decompressive procedures by 8 hours postinjury. One of the following three decompressive methods was used: 1) traction alone; 2) traction and surgery; or 3) surgery alone. Twenty-six patients from eight North American centers were entered into the study between 1996 and 1997. Significant difficulties were encountered in many centers in performing immediate magnetic resonance imaging examination in patients with acute SCI. Fewer than 10% of acute cervical SCI patients could be enrolled into this protocol mainly because the combination of the required time for rescue, resuscitation, transport, imaging study, and surgical preparation exceeded the 8-hour injury-to-decompressive surgery window. Eleven patients underwent decompressive procedures initially by being placed in traction at a mean time of 10.9 hours postinjury. Those patients not undergoing this procedure underwent decompressive surgery at a mean time of 40.1 hours. However, the surgical decompressive procedure was completed within 12 hours in seven patients. As a result of these findings, several major changes have been made to the STASCIS protocol for early decompressive therapy.

Methylprednisolone or tirilazad mesylate administration after acute spinal cord injury: 1-year follow up. Results of the third National Acute Spinal Cord Injury randomized controlled trial.

OBJECT: A randomized double-blind clinical trial was conducted to compare neurological and functional recovery and morbidity and mortality rates 1 year after acute spinal cord injury in patients who had received a standard 24-hour methylprednisolone regimen (24MP) with those in whom an identical MP regimen had been delivered for 48 hours (48MP) or those who had received a 48-hour tirilazad mesylate (48TM) regimen. METHODS: Patients for whom treatment was initiated within 3 hours of injury showed equal neurological and functional recovery in all three treatment groups. Patients for whom treatment was delayed more than 3 hours experienced diminished motor function recovery in the 24MP group, but those in the 48MP group showed greater 1-year motor recovery (recovery scores of 13.7 and 19, respectively, p=0.053). A greater percentage of patients improving three or more neurological grades was also observed in the 48MP group (p=0.073). In general, patients treated with 48TM recovered equally when compared with those who received 24MP treatments. A corresponding recovery in self care and sphincter control was seen but was not statistically significant. Mortality and morbidity rates at 1 year were similar in all groups. CONCLUSIONS: For patients in whom MP therapy is initiated within 3 hours of injury, 24-hour maintenance is appropriate. Patients starting therapy 3 to 8 hours after injury should be maintained on the regimen for 48 hours unless there are complicating medical factors.

Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study.

OBJECTIVE: To compare the efficacy of methylprednisolone administered for 24 hours with methyprednisolone administered for 48 hours or tirilazad mesylate administered for 48 hours in patients with acute spinal cord injury. DESIGN: Double-blind, randomized clinical trial. SETTING: Sixteen acute spinal cord injury centers in North America. PATIENTS: A total of 499 patients with acute spinal cord injury diagnosed in National Acute Spinal Cord Injury Study (NASCIS) centers within 8 hours of injury. INTERVENTION: All patients received an intravenous bolus of methylprednisolone (30 mg/kg) before randomization. Patients in the 24-hour regimen group (n=166) received a methylprednisolone infusion of 5.4 mg/kg per hour for 24 hours, those in the 48-hour regimen group (n=167) received a methylprednisolone infusion of 5.4 mg/kg per hour for 48 hours, and those in the tirilazad group (n=166) received a 2.5 mg/kg bolus infusion of tirilazad mesylate every 6 hours for 48 hours. MAIN OUTCOME MEASURES: Motor function change between initial presentation and at 6 weeks and 6 months after injury, and change in Functional Independence Measure (FIM) assessed at 6 weeks and 6 months. RESULTS: Compared with patients treated with methylprednisolone for 24 hours, those treated with methylprednisolone for 48 hours showed improved motor recovery at 6 weeks (P=.09) and 6 months (P=.07) after injury. The effect of the 48-hour methylprednisolone regimen was significant at 6 weeks (P=.04) and 6 months (P=.01) among patients whose therapy was initiated 3 to 8 hours after injury. Patients who received the 48-hour regimen and who started treatment at 3 to 8 hours were more likely to improve 1 full neurologic grade (P=.03) at 6 months, to show more improvement in 6-month FIM (P=.08), and to have more severe sepsis and severe pneumonia than patients in the 24-hour methylprednisolone group and the tirilazad group, but other complications and mortality (P=.97) were similar. Patients treated with tirilazad for 48 hours showed motor recovery rates equivalent to patients who received methylprednisolone for 24 hours. CONCLUSIONS: Patients with acute spinal cord injury who receive methylprednisolone within 3 hours of injury should be maintained on the treatment regimen for 24 hours. When methylprednisolone is initiated 3 to 8 hours after injury, patients should be maintained on steroid therapy for 48 hours.

Spinal cord mapping with evoked responses for accurate localization of the dorsal root entry zone.

Direct spinal cord stimulation and recording techniques were used intraoperatively to localize the dorsal root entry zone (DREZ) in four patients with brachial plexus avulsion and severe intractable pain. The spinal cord was stimulated by a cordotomy needle placed on the pia-arachnoid at the DREZ or the dorsal or dorsolateral aspect of the spinal cord. Recordings were obtained from a subdural silver ball electrode placed rostral or caudal to the stimulation site. Spinal cord conduction velocity was significantly faster following dorsolateral stimulation than dorsal stimulation (mean = 66 and 45 m/sec respectively). The spinal cord evoked potential was significantly larger in amplitude following dorsolateral stimulation than dorsal stimulation at a specific stimulus intensity. Stimulation at the DREZ failed to evoke a response. These neurophysiological phenomena helped to accurately localize the DREZ before DREZ lesioning was undertaken. There were no untoward neurological deficits related to the DREZ lesions and all patients had satisfactory pain relief following the procedure. Intraoperative spinal cord mapping facilitates accurate DREZ localization when the DREZ cannot be visually identified.

Dorsal root entry zone localization using direct spinal cord stimulation: an experimental study.

Direct spinal cord stimulation and recording was performed in five dogs to identify the dorsal root entry zone (DREZ) and long tracts within the dorsal and dorsolateral spinal cord using electrophysiological mapping techniques. Intrathecal recordings were obtained from sites distal to the site of stimulation. Conduction velocity in the fastest conducting fibers was higher following low-intensity stimulation of the dorsolateral spinal cord than after dorsal spinal cord stimulation. The evoked response was larger following dorsolateral than dorsal spinal cord stimulation at a specific stimulus intensity. This technique is useful in identifying the DREZ using electrophysiological criteria alone.

Canal clearance in burst fractures using the AO internal fixator.

The purpose of this study was to evaluate the ability of posterior distraction delivered by the AO internal fixator to effect a satisfactory reduction of the intraspinal fragments in burst fractures. The overall decompression achieved was from an initial compromise of 54% to a residual encroachment of 40%. Canal clearance proved most effective when carried out in the first 4 days, with an initial canal compromise of between 34 and 66%. The extent of improvement, even in this group, was not dramatic, with an average of 31% encroachment still remaining, with some cases as high as 50%. Therefore, we recommend that when canal clearance is essential, anterior decompression is the treatment of choice.

Correlation between cerebral blood flow, somatosensory evoked potentials, CT scan grade and neurological grade in patients with subarachnoid hemorrhage.

Cerebral blood flow (CBF) and central conduction time (CCT) were recorded from 58 subarachnoid hemorrhage patients and from 49 age-matched controls. CBF was calculated following Xenon inhalation and CCT was determined from somatosensory evoked potentials (SSEP's) following median nerve stimulation. Each patient had a CT scan on the day of admission which was graded from I-IV. CBF, CCT and neurological grade (Hunt and Hess classification) were concomitantly recorded 1, 4, 7 and 14 days after subarachnoid hemorrhage. Mean CBF was highest in patients with neurological grades I and II (48.6 +/- 12.3 and 48.1 +/- 10.3 ml/100gm/min respectively) and lowest in patients with neurological grade IV (37.3 +/- 9.6 ml/100gm/min). Patients in neurological grade I or II had mean CBF and CCT measurements that were significantly different from those obtained from patients in neurological grade IV (P less than 0.05). Neurological grade and CT scan grade correlated with CBF (P less than 0.0001) better than CCT (P = 0.015). Unexpectedly low CBF's from patients in neurological grades II and III (less than 37 and less than 31 ml/100gm/min respectively) failed to significantly prolong CCT suggesting CCT is unable to detect marginal ischemia. A significant correlation between CBF and CCT occurred only when CBF was less than 30 ml/100gm/min (R = 0.75, P = 0.05). It appears that prolonged CCT is associated with a drop in CBF only when CBF drops below a certain threshold.

Posttraumatic ligamentous disruption of the cervical spine, an easily overlooked diagnosis: presentation of three cases.

Three patients with hyperflexion sprain of the cervical spine secondary to motor vehicle accidents are discussed. One patient exhibited tetraplegia and the other two only had paresthesia of the upper and/or lower extremities at the scene of the accident. All patients were young with no evidence of degenerative disc disease or osteoarthritis. Diagnosis of hyperflexion sprain is suggested by transient or persistent neurological deficits, local tenderness, or plain film findings, which include interspinous fanning, localized kyphotic angulation, subluxation, or disc space narrowing. Review of our patients' records revealed that some of these findings were evident at their initial presentation. In patients who have no neurological deficits, controlled flexion and extension views after routine plain films may be diagnostic of an unstable cervical spine. If there is a persistent neurological deficit, a magnetic resonance imaging scan is the examination of choice. If there is no compression of the thecal sac or spinal cord, supervised flexion and extension views of cervical spine should be done. Definitive management of the unstable spine is operative fixation.

Results of a locking-hook spinal rod for fractures of the thoracic and lumbar spine.

The results of a consecutive series of 110 patients treated with the locking-hook spinal rod are presented. A prospective protocol was completed in 95 patients. Pain was absent or mild in 93%. In those patients with a partial neurologic deficit, there was recovery of at least one Frankel grade in 84%. The overall kyphotic deformity was reduced from 21 to 17 degrees. In those patients in whom no anterior surgery was performed, the deformity improved from 21 to 13 degrees. No rod fractures occurred, and the overall instrument complication rate was 13.7%, of which one was due to infection and four secondary to uncrimped nuts, for a true complication rate of 8.4%. The locking-hook spinal rod has proven to be a satisfactory internal fixation device in the treatment of unstable thoracolumbar fractures.

Prediction of stability of cervical spine fracture managed in the halo vest and indications for surgical intervention.

A retrospective study was made of 173 cases of acute cervical spine injury with halo vest management to compare initial injury features with outcome. The object was to determine whether a mathematical model could be developed enabling a prediction to be made at the time of the initial assessment as to the probability of success or failure of conservative management using the halo vest alone, and thus perhaps avoid lengthy, unsuccessful treatment. Patients with facet joint dislocation were found to form a distinct subgroup of the injury population. Of the 70 patients in this subgroup, 44% achieved stability with the halo vest alone, but half of these had a "poor anatomical result." No mathematical model or associated injury features could be found to assist in the outcome prediction in this subgroup. Of the 103 patients without facet joint dislocation, 70% achieved stability with the vest alone and over 75% of these had a "good anatomical result." A useful model of outcome prediction was found for this subgroup by logistic regression analysis; the two most important predictors in the model were the amount of subluxation and the degree of angulation in the sagittal plane.

Isolated basilar artery occlusion associated with a clivus fracture.

Most vascular injuries to the brain secondary to blunt head trauma involve the internal carotid circulation. A case of isolated basilar occlusion secondary to a clival fracture is described and compared to three other cases in the literature.

Functional recovery after decompressive craniectomy for cerebral infarction.

There is continuing controversy about the benefits of decompressive craniectomy in the treatment of lesions causing increased intracranial pressure (ICP) and brain edema. Laboratory work has shown a decrease in ICP after craniectomy, but also a paradoxical enhancement in the formation of underlying cerebral edema, which may act to the detriment of the patient. Since Rengachary et al. advocated craniectomy for massive cerebral infarction and reported their group of three patients, we have managed five patients with acute supratentorial cerebral infarction who progressed to uncal herniation and impending death from raised ICP and brain stem compression. All were treated with frontotemporal craniectomy after conventional medical therapy failed to achieve a response. All patients survived and are walking, despite a paresis appropriate to their original stroke. Two have returned to work. Good results with supratentorial craniectomy after infarction show that this procedure is life-saving and can also give acceptable functional recovery.

Decompression and circumferential stabilization of unstable spinal fractures.

A technique of anterior decompression of the spinal canal with anterior strut grafts, followed by posterior instrumentation and local fusion, is described in a group of 18 patients with unstable thoracolumbar fractures. All patients were found to have greater than 50% encroachment of the spinal canal and a preoperative kyphosis of 21.8 degrees. At follow-up 81% of patients with incomplete neurological lesions improved at least one Frankel Grade. Residual encroachment on the spinal canal was 4.6% and at follow-up the kyphotic angle was 17.1 degrees. Complications included one anterior graft loosening (not requiring revision), three loosened rods, only one of which required revision, and one fractured Harrington rod which did not require revision. The authors conclude that this technique is an effective and safe method for treating unstable thoracolumbar injuries and is recommended if anterior instrumentation is unavailable.

The neurological outcome following surgery for spinal fractures.

Sixty consecutive patients with spinal injuries and encroachment upon the spinal canal of greater than 20% were assessed for neurological outcome. The patients were divided into two groups, those undergoing posterior surgery alone, and those undergoing anterior surgery for formal decompression with or without anterior or posterior instrumentation. In those patients undergoing posterior surgery, an improvement rate in the neurological function of 83% was noted in patients with incomplete lesions, whereas an 88% improvement rate was found in those undergoing the anterior procedure. There was no statistical difference in outcome between these two groups. Positive correlations were found between the level of injury and Frankel grades. The cord lesions tended to demonstrate more severe neurological deficit, whereas the cauda equina lesions were associated with a lesser severity of neurologic deficit. A component of dislocation to the injury also resulted in a more severe neurological deficit. There was no apparent difference between the degree of bony encroachment of the spinal canal and the initial Frankel grade, nor was there a clear difference between those patients undergoing anterior versus posterior surgery.

The radiology of sacral cysts.

The radiological findings in 10 patients with sacral cysts were retrospectively reviewed and classified. The cysts were an incidental finding on computed tomography (CT) in four patients. The expansion of sacral foramina or the sacral canal as seen on plain films suggested the diagnosis in three. In only two of the five patients who had myelograms did the cysts fill with contrast. In eight, CT showed remodelling and expansion of the sacral foramina, or the canal, or both, by a homogeneous mass with a density of 5-20 Hounsfield units. One of the patients underwent magnetic resonance imaging which confirmed that the lesion was fluid-filled. We found that sacral cysts can be either symptomatic or asymptomatic, that they may or may not communicate with the subarachnoid space, and that they have a characteristic CT appearance.

Computed tomography of a sacral perineural cyst.

The CT findings of a symptomatic sacral perineural cyst are presented. The cyst failed to fill on a metrizamide myelogram. The CT findings are very suggestive of the diagnosis.