Our findings provide proof-of-principle that subdural intraspinal pressure at the injury site can be measured safely after traumatic spinal cord injury.

We recently showed that, after traumatic spinal cord injury (TSCI), laminectomy does not improve intraspinal pressure (ISP), spinal cord perfusion pressure (SCPP), or the vascular pressure reactivity index (sPRx) at the injury site sufficiently because of dural compression. This is an open label, prospective trial comparing combined bony and dural decompression versus laminectomy. Twenty-one patients with acute severe TSCI had re-alignment of the fracture and surgical fixation; 11 had laminectomy alone (laminectomy group) and 10 had laminectomy and duroplasty (laminectomy+duroplasty group). Primary outcomes were magnetic resonance imaging evidence of spinal cord decompression (increase in intradural space, cerebrospinal fluid around the injured cord) and spinal cord physiology (ISP, SCPP, sPRx). The laminectomy and laminectomy+duroplasty groups were well matched. Compared with the laminectomy group, the laminectomy+duroplasty group had greater increase in intradural space at the injury site and more effective decompression of the injured cord. In the laminectomy+duroplasty group, ISP was lower, SCPP higher, and sPRx lower, (i.e., improved vascular pressure reactivity), compared with the laminectomy group. Laminectomy+duroplasty caused cerebrospinal fluid leak that settled with lumbar drain in one patient and pseudomeningocele that resolved completely in five patients. We conclude that, after TSCI, laminectomy+duroplasty improves spinal cord radiological and physiological parameters more effectively than laminectomy alone.

OBJECTIVE:There is lack of monitoring from the injury site to guide management of patients with acute traumatic spinal cord injury. Here we describe a bedside microdialysis monitoring technique for optimizing spinal cord perfusion and drug delivery at the injury site.METHODS: 14 patients were recruited within 72 hours of severe spinal cord injury. We inserted intradurally at the injury site a pressure probe, to monitor continuously spinal cord perfusion pressure, and a microdialysis catheter, to monitor hourly glycerol, glutamate, glucose, lactate and pyruvate. The pressure probe and microdialysis catheter were placed on the surface of the injured cord. RESULTS:Microdialysis monitoring did not cause serious complications. Spinal cord perfusion pressure 90 -100 mmHg and tissue glucose >4.5 mM minimized metabolic derangement at the injury site. Increasing spinal cord perfusion pressure by ~10 mmHg, increased the entry of intravenously administered dexamethasone at the injury site three-fold. INTERPRETATION:This study determined the optimum spinal cord perfusion pressure and optimum tissue glucose concentration at the injury site. We also identified spinal cord perfusion pressure as a key determinant of drug entry into the injured spinal cord. Our findings challenge current guidelines, which recommend maintaining mean arterial pressure at 85 -90 mmHg for a week after spinal cord injury. We propose that future drug trials for spinal cord injury include pressure and microdialysis monitoring to optimize spinal cord perfusion and maximize drug delivery at the injury site.

The aim of this study was to examine how traumatic spinal cord injury is managed in the United Kingdom via a questionnaire survey of all neurosurgical units. We contacted consultant neurosurgeons and neuroanesthetists in all neurosurgical centers that manage patients with acute spinal cord injury. Two clinical scenarios-of complete and incomplete cervical spinal cord injuries-were given to determine local treatment policies. There were 175 responders from the 33 centers (36% response rate). We ascertained neurosurgical views on urgency of transfer, timing of surgery, nature and aim of surgery, as well as neuroanesthetic views on type of anesthetic, essential intraoperative monitoring, drug treatment, and intensive care management. Approximately 70% of neurosurgeons will admit patients with incomplete spinal cord injury immediately, but only 40% will admit patients with complete spinal cord injury immediately. There is no consensus on the timing or even the role of surgery for incomplete or complete injuries. Most (96%) neuroanesthetists avoid anesthetics known to elevate intracranial pressure. What was deemed essential intraoperative monitoring, however, varied widely. Many (22%) neuroanesthetists do not routinely measure arterial blood pressure invasively, central venous pressure (85%), or cardiac output (94%) during surgery. There is no consensus among neuroanesthetists on the optimal levels of arterial blood pressure, or oxygen and carbon dioxide partial arterial pressure. We report wide variability among U.K. neurosurgeons and neuroanesthetists in their treatment of acute traumatic spinal cord injury. Our findings reflect the lack of Class 1 evidence that early surgical decompression and intensive medical management of patients with spinal cord injury improves neurological outcome.

OBJECTIVE A novel technique for monitoring intraspinal pressure and spinal cord perfusion pressure in patients with traumatic spinal cord injury was recently described. This is analogous to monitoring intracranial pressure and cerebral perfusion pressure in patients with traumatic brain injury. Because intraspinal pressure monitoring is a new technique, its safety profile and impact on early patient care and long-term outcome after traumatic spinal cord injury are unknown. The object of this study is to review all patients who had intraspinal pressure monitoring to date at the authors' institution in order to define the accuracy of intraspinal pressure probe placement and the safety of the technique. METHODS At the end of surgery to fix spinal fractures, a pressure probe was inserted intradurally to monitor intraspinal pressure at the injury site. Postoperatively, CT scanning was performed within 48 hours and MRI at 2 weeks and 6 months. Neurointensive care management and complications were reviewed. The American Spinal Injury Association Impairment Scale (AIS) grade was determined on admission and at 2 to 4 weeks and 12 to 18 months postoperation. RESULTS To date, 42 patients with severe traumatic spinal cord injuries (AIS Grades A–C) had undergone intraspinal pressure monitoring. Monitoring started within 72 hours of injury and continued for up to a week. Based on postoperative CT and MRI, the probe position was acceptable in all patients, i.e., the probe was located at the site of maximum spinal cord swelling. Complications were probe displacement in 1 of 42 patients (2.4%), CSF leakage that required wound resuturing in 3 of 42 patients (7.1%), and asymptomatic pseudomeningocele that was diagnosed in 8 of 42 patients (19.0%). Pseudomeningocele was diagnosed on MRI and resolved within 6 months in all patients. Based on the MRI and neurological examination results, there were no serious probe-related complications such as meningitis, wound infection, hematoma, wound breakdown, or neurological deterioration. Within 2 weeks postoperatively, 75% of patients were extubated and 25% underwent tracheostomy. Norepinephrine was used to support blood pressure without complications. Overall, the mean intraspinal pressure was around 20 mm Hg, and the mean spinal cord perfusion pressure was around 70 mm Hg. In laminectomized patients, the intraspinal pressure was significantly higher in the supine than lateral position by up to 18 mm Hg after thoracic laminectomy and 8 mm Hg after cervical laminectomy. At 12 to 18 months, 11.4% of patients had improved by 1 AIS grade and 14.3% by at least 2 AIS grades. CONCLUSIONS These data suggest that after traumatic spinal cord injury intradural placement of the pressure probe is accurate and intraspinal pressure monitoring is safe for up to a week. In patients with spinal cord injury who had laminectomy, the supine position should be avoided in order to prevent rises in intraspinal pressure.