Failure of topical DMSO to improve blood flow or evoked potentials in rat spinal cord injury.

Dimethyl sulfoxide (DMSO) is a well-known hydroxyl radical scavenger, which is readily absorbed through biological membranes. We studied the effects of locally applied DMSO on acute spinal cord injury. Either 10% DMSO in saline (n=8) or saline alone (n=7) was applied directly to the exposed cervical spinal cord of rats 1 hour after clip compression injury of 26 g force for 1 minute.

Stereotactic radiosurgery for acoustic neuroma: a Canadian perspective.

Stereotactically delivered radiation is now an accepted treatment for patients with acoustic neuroma. In some cases, patient preference may be the reason for its selection, while in others neurosurgeons may select it for patients who are elderly or have significant risk factors for conventional surgery. The majority of patients with acoustic neuroma treatment with stereotactic radiosurgery have been treated with the Gamma Knife, with follow ups of over 25 years in some instances.

Surgical research in Canada: synopsis of a consensus conference.

Canadian surgical research requires careful nurturing if it is to flourish in tomorrow's environment. A consensus conference organized by the Research Development Committee of the Canadian Association of Surgical Chairs has addressed a number of issues to promote Canadian surgical research. This synopsis is a summary of the proceedings of that conference.

Effect of intrathecal nimodipine on spinal cord blood flow and evoked potentials in the normal or injured cord.

A method was developed for administering intrathecal pharmacotherapy in a rat model of spinal cord injury. The effects of intrathecal administration of nimodipine on spinal cord blood flow (SCBF) and evoked potentials (EPs) were measured in the normal and injured spinal cord. It had previously been shown that systemic nimodipine caused severe hypotension after spinal cord injury.

Prevention of arachnoiditis and postoperative tethering of the spinal cord with Gore-Tex surgical membrane: an experimental study with rats.

Objective: Arachnoidal adhesions and inflammation were evaluated in 72 rats after spinal dural repair with one of three materials, i.e., Gore-Tex surgical membrane, collagen-coated Vicryl mesh, or lyophilized spinal dural allograft.

Biology of neurological recovery and functional restoration after spinal cord injury.

Objective: This article reviews the anatomic and pathophysiological bases for recovery of neurological function after experimental or clinical spinal cord injury (SCI).

Methods: Current knowledge regarding the recovery of neurological function after experimental or clinical SCI was reviewed to determine the biological basis of neurological recovery.

Results: There is a great propensity for recovery after clinical or experimental SCI.

Spinal injuries in ice hockey.

SportSmart Canada maintains a registry of spinal injuries in hockey and has documented 214 cases of fracture or dislocation of the spine, occurring mainly in North America since 1966. The current annual incidence is approximately 15 cases per year and may be declining as a result of intense prevention programs. Most of the injuries have been to the cervical spine in players 16 to 20 years of age playing supervised games.

Occipital condyle fractures.

Objective: Occipital condyle fractures (OCFs) are infrequently recognized. Three recent cases of OCF in our center prompted a review of the incidence, clinical presentation, diagnosis, and treatment of this entity.

Methods: A retrospective review of medical records and radiographic results was performed for 93 of 316 consecutive patients who were victims of trauma, who presented at the Toronto Hospital during a 13-month period, and who had undergone computed tomography of the occiput.

Post-operative radiotherapy for recurrent dermoid cysts of the spine: a report of 3 cases.

We report three cases of recurrent, intraspinal dermoid cysts managed with post-operative radical radiotherapy. In all cases, the period between last surgery and cystic re-accumulation has been lengthened by the use of involved-field radiotherapy. This combined-modality approach could be beneficial in decreasing the probability of recurrence associated with incompletely-resected tumours, or in patients whose co-morbidities put them at increased operative risk for serial neurosurgical procedures.

Effect of a single huge dose of methylprednisolone on blood flow, evoked potentials, and histology after acute spinal cord injury in the rat.

Effects of a single, huge dose of methylprednisolone on post-traumatic spinal cord blood flow (SCBF), evoked potentials and histological changes were studied in a rat model of spinal cord injury. The purpose of this study was to assess the optimal dose of methylprednisolone for the treatment of rat spinal cord injury. Twenty-five male Wistar rats were subjected to an acute clip compression injury at 51 g for 1 min at C8-T1, and then received an intravenous bolus injection of one of the following 30 min after injury: vehicle, 30, 60, 120 or 240 mg kg-1 methylprednisolone.

Multilevel anterior cervical corpectomy and fibular allograft fusion for cervical myelopathy.

This study was conducted to determine the safety and efficacy of multilevel anterior cervical corpectomy and stabilization using fibular allograft in patients with cervical myelopathy. Thirty-six patients underwent this procedure for cervical myelopathy caused by spondylosis (20 patients), ossified posterior longitudinal ligament (four patients), trauma (one patient), or a combination of lesions (11 patients). The mean age (+/- standard deviation) of the patients was 58 +/- 10 years and 30 of the patients were men.

Serial recording of somatosensory and myoelectric motor evoked potentials: role in assessing functional recovery after graded spinal cord injury in the rat.

Accurate functional outcome measures are essential in assessing therapeutic interventions after experimental spinal cord injury (SCI). We examined the hypothesis that serial recording of somatosensory (SSEP) and myoelectric motor evoked potentials (mMEPs) would provide complementary information to standard methods of behavioral analysis in a rat model of SCI and would allow objective discrimination of functional recovery in sensory and motor tracts. Clip compression injury of varying severity (sham, 23 g, 34 g, 56 g) and transections were performed at T1 in adult rats.

Vascular mechanisms in the pathophysiology of human spinal cord injury.

Vascular injury plays an important role in the primary and secondary injury mechanisms that cause damage to the acutely traumatized spinal cord. To understand the pathophysiology of human spinal cord injury, the authors investigated the vascular system in three uninjured human spinal cords using silicone rubber microangiography and analyzed the histological findings related to vascular injury in nine acutely traumatized human spinal cords obtained at autopsy. The interval from spinal cord injury to death ranged from 20 minutes to 9 months.

New spinal injuries in hockey.

Objectives: In this study, we wished to examine the nature and incidence of major spinal injuries sustained by ice hockey players and to add reported cases to a permanent registry.

Design: The study was a retrospective review of questionnaires returned by physicians reporting spinal injuries due to ice hockey.

Setting: Canada primarily, with reported cases from other nations.

The effects of cortical stimulation, anesthesia and recording site on somatosensory evoked potentials in the rat.

The purpose of this study was to standardize the method of spinal cord monitoring with evoked potentials in the rat. Seventeen male Wistar rats were anesthetized with alpha-chloralose and urethane. Somatosensory evoked potential (SEP) and cerebellar evoked potential (CEP) following sciatic nerve stimulation were mapped at different time points after induction of anesthesia.

Ultrastructural evidence for arteriolar vasospasm after spinal cord trauma.

Objective: The primary objective of this study was to investigate the potential contribution of vasospasm to the cascade of secondary injury process after traumatic spinal cord injury. Although ischemic factors have been implicated, in that vessel rupture, compression, and intravascular thrombosis are readily identifiable, vasospasm has been more difficult to detect.

Methods: The sulcal arterioles in the ventral median fissure of the cervical spinal cord from adult rats were quantitatively examined at the ultrastructural level up to 24 hours after compression injury.

Normal and abnormal calcium homeostasis in neurons: a basis for the pathophysiology of traumatic and ischemic central nervous system injury.

Clinical recovery after central nervous system (CNS) trauma or ischemia may be limited by a neural injury process that is triggered and perpetuated at the cellular level, rather than by a lesion amenable to surgical repair. It is widely thought that one such process, a fundamental pathological mechanism initiated by CNS injury, is a disruption of cellular Ca2+ homeostasis. Because of the critical role of Ca2+ ions in regulating innumerable cellular functions, this major homeostatic disturbance is thought to trigger neuronal and axonal degeneration and produce clinical disability.

Voltage-sensitive calcium channels mediate calcium entry into cultured mammalian sympathetic neurons following neurite transection.

Calcium ion entry following mechanical neurite transection was examined in cultured sympathetic neurons loaded with the Ca2+ indicator fluo-3. Neurite transection produced a rapid [Ca2+]i rise in the cell soma which preceded any [Ca2+]i rise in the neurite (n = 30). Blocking sodium channels with tetrodotoxin had no effect on the Ca2+ rise, but inactivating voltage-sensitive Ca2+ channels by bath-applying 140 mM potassium prior to the transection, and the simultaneous application of nimodipine and omega-conotoxin GVIA, blockers of L-type and N-type Ca2+ channels, respectively, considerably attenuated the Ca2+ rise in the soma and neurites.

Clinical syndromes associated with disproportionate weakness of the upper versus the lower extremities after cervical spinal cord injury.

Patients with cervical spinal cord injuries who present with weakness or paralysis of the hands and arms with relative preservation of lower extremity strengths are often categorized as having two clinical syndromes, cruciate paralysis and acute central cervical spinal cord injury. The explanation for the pathophysiological findings of the dissociated strength in the upper versus the lower extremities has relied on the assumption that there is a localized injury within a somatotopically organized corticospinal tract. This article summarizes the evidence that there is no somatotopic organization within the corticospinal tract in the medulla or cervical spinal cord in primates.

Characterization of axonal ultrastructural pathology following experimental spinal cord compression injury.

The present study characterizes axonal pathology associated with traumatic compression injuries of the spinal cord and quantitatively assesses subtypes of axonal pathology in the acute, post-injury period. Eighteen adult female Wistar rats underwent spinal cord compression injury with a 53 g modified aneurysm clip at the C8-T1 segment. Six additional rats served as sham controls.

Update on the pathophysiology and pathology of acute spinal cord injury.

There is evidence from both clinical and experimental studies that the spinal cord suffers both primary and secondary damage after acute spinal cord injury. The pathophysiology of secondary injury involves a multitude of cellular and molecular events which progress over the first few days after injury, the most important of which are systemic and local vascular insults, electrolyte shifts, oedema and excitotoxicity. These secondary processes contribute to the evolution of the pathological changes which in the severe injuries progress from central haemorrhagic necrosis involving mainly the grey matter to infarction of both the white and grey matter at the injury site and for a considerable distance proximally and distally.

C1-C2 posterior cervical fusion: long-term evaluation of results and efficacy.

Posterior wiring techniques are the most commonly used methods of achieving C1-C2 arthrodesis. Recently, transarticular screw fixation and interlaminar clamping have been advocated to achieve more secure fixation. A retrospective review of patients undergoing C1-C2 fusion for nonneoplastic disease was undertaken at the University of Toronto Hospital, with the aim of determining the long-term outcome of the selected procedures.