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The primary objective of this biomechanical study was to investigate the effect of decompressive surgery, specifically dorsal laminectomy and discectomy, on the stability of the lumbosacral joint in the dog. Different size laminectomies were compared with respect to their effect on lumbosacral stability. A total of eighteen lumbosacral motion units were collected from cadavers and divided into three groups. Group 1 was a control group and received no modification, Group 2 specimens received mini-dorsal laminectomies and discectomies (lamina of L7 caudal to the dorsal spinous process excised, lamina of S1 not affected) while Group 3 specimens received standard dorsal laminectomies and discectomies (75% of L7 lamina and 50% of S1 lamina excised). All specimens were potted in aluminium tubing and mounted in a four-point bending jig and tested in a load cell. Specimens were stressed to 21° in dorsiflexion and ventroflexion. The relevant surgical modification was then performed and the specimens re-tested to 21° in dorsiflexion and ventroflexion. All specimens were then tested to failure in ventroflexion. Force and angular displacement was recorded and used to obtain load-deformation curves for each specimen (5 curves for each specimen). From the load-deformation curves the stiffness (gradient of the graph) was determined at three set angles of deflection. These points were 6°-8°, 12°-16° and 18°-20°. The percentage change in stiffness for each specimen in both dorsiflexion and ventroflexion was obtained. Peak force at failure and angular deformation at failure were obtained when tested to failure in ventroflexion. When examining the overall stiffness of the specimen (dorsiflexion and ventroflexion and all angles of deflection) mini-dorsal laminectomy was shown to result in a 48.3% reduction in stiffness (P < 0.001) while standard dorsal laminectomy and discectomy resulted in a 59.8% reduction in stiffness (P < 0.001). These results were statistically significant. The difference between the two different types of laminectomies could be described as approaching significance (P=0.066). Larger group size would be required to determine whether this is in fact statistically significant Dorsal laminectomy combined with discectomy does have an effect on the stability of the lumbosacral joint. This may contribute to the relatively high recurrence rate following surgical treatment of degenerative lumbosacral stenosis especially in large breed highly active dogs. The study provides further support for decompressive surgery combined with a stabilisation technique when treating degenerative lumbosacral stenosis. It also provides potential support for the use of mini-dorsal laminectomies. / Dissertation (MMedVet)--University of Pretoria, 2009. / Companion Animal Clinical Studies / unrestricted

Background Moderate hypothermia after decompressive surgery might not be beneficial for stroke patients. However, normothermia may prove to be an effective method of enhancing neurological outcomes. The study aims were to evaluate the application of a pre-specified normothermia protocol in stroke patients after decompressive surgery and its impact on temperature load, and to describe the functional outcome of patients at 12 months after treatment. Methods We analysed patients with space-occupying middle cerebral artery (MCA) infarction treated with decompressive surgery and a pre-specified temperature management protocol. Patients treated primarily with device-controlled normothermia or hypothermia were excluded. The individual temperature load above 36.5 °C was calculated for the first 96 h after hemicraniectomy as the Area Under the Curve, using °C x hours. The effect of temperature load on functional outcome at 12 months was analysed by logistic regression. Results We included 40 stroke patients treated with decompressive surgery (mean [SD] age: 58.9 [10.1] years; mean [SD] time to surgery: 30.5 [16.7] hours). Fever (temperature > 37.5 °C) developed in 26 patients during the first 96 h after surgery and mean (SD) temperature load above 36.5 °C in this time period was 62,3 (+/− 47,6) °C*hours. At one year after stroke onset, a moderate to moderately severe disability (modified Rankin Scale score of 3 or 4) was observed in 32% of patients, and a severe disability (score of 5) in 37% of patients, respectively. The lethality in the cohort at 12 months was 32%. The temperature load during the first 96 h was not an independent predictor for 12 month lethality (OR 0.986 [95%-CI:0.967–1.002]; p < 0.12). Conclusions Temperature control in surgically treated patients with space-occupying MCA infarction using a pre-specified protocol excluding temperature management systems resulted in mild hyperthermia between 36.8 °C and 37.2 °C and a low overall temperature load. Future prospective studies on larger cohorts comparing different strategies for normothermia treatment including temperature management devices are needed.

Background: The optimal timing of surgical therapy for traumatic spinal cord injury (TSCI) remains unclear. The purpose of this study is to evaluate the impact of “ultra-early” (<4 h) versus “early” (4–24 h) time from injury to surgery in terms of the likelihood of neurologic recovery. Methods: The effect of surgery on neurological recovery was investigated by comparing the assessed initial and final values of the American Spinal Injury Association (ASIA) Impairment Scale (AIS). A post hoc analysis was performed to gain insight into different subgroup regeneration behaviors concerning neurological injury levels. Results: Datasets from 69 cases with traumatic spinal cord injury were analyzed. Overall, 19/46 (41.3%) patients of the “ultra-early” cohort saw neurological recovery compared to 5/23 (21.7%) patients from the “early” cohort (p = 0.112). The subgroup analysis revealed differences based on the neurological level of injury (NLI) of a patient. An optimal cutpoint for patients with a cervical lesion was estimated at 234 min. Regarding the prediction of neurological improvement, sensitivity was 90.9% with a specificity of 68.4%, resulting in an AUC (area under the curve) of 84.2%. In thoracically and lumbar injured cases, the estimate was lower, ranging from 284 (thoracic) to 245 min (lumbar) with an AUC of 51.6% and 54.3%. Conclusions: Treatment within 24 h after TSCI is associated with neurological recovery. Our hypothesis that intervention within 4 h is related to an improvement in the neurological outcome was not confirmed in our collective. In a clinical context, this suggests that after TSCI there is a time frame to get the right patient to the right hospital according to advanced trauma life support (ATLS) guidelines.

Background Moderate hypothermia after decompressive surgery might not be beneficial for stroke patients. However, normothermia may prove to be an effective method of enhancing neurological outcomes. The study aims were to evaluate the application of a pre-specified normothermia protocol in stroke patients after decompressive surgery and its impact on temperature load, and to describe the functional outcome of patients at 12 months after treatment. Methods We analysed patients with space-occupying middle cerebral artery (MCA) infarction treated with decompressive surgery and a pre-specified temperature management protocol. Patients treated primarily with device-controlled normothermia or hypothermia were excluded. The individual temperature load above 36.5 °C was calculated for the first 96 h after hemicraniectomy as the Area Under the Curve, using °C x hours. The effect of temperature load on functional outcome at 12 months was analysed by logistic regression. Results We included 40 stroke patients treated with decompressive surgery (mean [SD] age: 58.9 [10.1] years; mean [SD] time to surgery: 30.5 [16.7] hours). Fever (temperature > 37.5 °C) developed in 26 patients during the first 96 h after surgery and mean (SD) temperature load above 36.5 °C in this time period was 62,3 (+/− 47,6) °C*hours. At one year after stroke onset, a moderate to moderately severe disability (modified Rankin Scale score of 3 or 4) was observed in 32% of patients, and a severe disability (score of 5) in 37% of patients, respectively. The lethality in the cohort at 12 months was 32%. The temperature load during the first 96 h was not an independent predictor for 12 month lethality (OR 0.986 [95%-CI:0.967–1.002]; p < 0.12). Conclusions Temperature control in surgically treated patients with space-occupying MCA infarction using a pre-specified protocol excluding temperature management systems resulted in mild hyperthermia between 36.8 °C and 37.2 °C and a low overall temperature load. Future prospective studies on larger cohorts comparing different strategies for normothermia treatment including temperature management devices are needed.