Predictors of Intraspinal Pressure and Optimal Cord Perfusion Pressure After Traumatic Spinal Cord Injury.

BACKGROUND/OBJECTIVES: We recently developed techniques to monitor intraspinal pressure (ISP) and spinal cord perfusion pressure (SCPP) from the injury site to compute the optimum SCPP (SCPPopt) in patients with acute traumatic spinal cord injury (TSCI). We hypothesized that ISP and SCPPopt can be predicted using clinical factors instead of ISP monitoring. METHODS: Sixty-four TSCI patients, grades A-C (American spinal injuries association Impairment Scale, AIS), were analyzed. For 24 h after surgery, we monitored ISP and SCPP and computed SCPPopt (SCPP that optimizes pressure reactivity). We studied how well 28 factors correlate with mean ISP or SCPPopt including 7 patient-related, 3 injury-related, 6 management-related, and 12 preoperative MRI-related factors. RESULTS: All patients underwent surgery to restore normal spinal alignment within 72 h of injury. Fifty-one percentage had U-shaped sPRx versus SCPP curves, thus allowing SCPPopt to be computed. Thirteen percentage, all AIS grade A or B, had no U-shaped sPRx versus SCPP curves. Thirty-six percentage (22/64) had U-shaped sPRx versus SCPP curves, but the SCPP did not reach the minimum of the curve, and thus, an exact SCPPopt could not be calculated. In total 5/28 factors were associated with lower ISP: older age, excess alcohol consumption, nonconus medullaris injury, expansion duroplasty, and less intraoperative bleeding. In a multivariate logistic regression model, these 5 factors predicted ISP as normal or high with 73% accuracy. Only 2/28 factors correlated with lower SCPPopt: higher mean ISP and conus medullaris injury. In an ordinal multivariate logistic regression model, these 2 factors predicted SCPPopt as low, medium-low, medium-high, or high with only 42% accuracy. No MRI factors correlated with ISP or SCPPopt. CONCLUSIONS: Elevated ISP can be predicted by clinical factors. Modifiable factors that may lower ISP are: reducing surgical bleeding and performing expansion duroplasty. No factors accurately predict SCPPopt; thus, invasive monitoring remains the only way to estimate SCPPopt

Arterial injury in the lower limb from blunt trauma

BackgroundThe present study was performed to identify the factors associated with amputation in patients with blunt injuries to the lower limb associated with arterial injury. The ability of a scoring system to predict the outcome was tested.MethodsThere were 122 lower limb arterial injuries in 119 patients treated at the Royal Adelaide Hospital in the years 1962-1994. Prognostic factors considered were the site of the injury, the severity of the soft-tissue injury and shock, the presence of associated injuries and a description of the bone or joint injury. The mangled extremity severity score (MESS) was calculated retrospectively for each patient.ResultsThe outcome was primary amputation in 27 patients, delayed amputation in 36 patients and limb salvage in 59 patients. The seven deaths were all due to associated injuries. Factors associated with amputation were the severity of shock and soft-tissue injury (P ConclusionsThe major factor determining outcome was the severity of the soft-tissue injury. Progressive necrosis and infection was a major cause of late amputation. The MESS is not sufficiently precise to allow the decision regarding amputation to be made at the initial operation

The mangled extremity and attempt for limb salvage

<p>Abstract</p> <p>Background</p> <p>The decision, whether to amputate or reconstruct a mangled extremity remains the subject of extensive debate since multiple factors influence the decision.</p> <p>Methods</p> <p>Sixty three patients with high energy extremity trauma and attempts at limb salvage were retrospectively reviewed. We analyzed 10 cases of massive extremity trauma where there was made an attempt to salvage limbs, although there was a controversy between salvage and amputation.</p> <p>Results</p> <p>All of the patients except one had major vascular injury and ischemia requiring repair. Three patients died. All of the remaining patients were amputated within 15 days after the salvage procedure, mainly because of extremity sepsis. Seven patients required treatment at the intensive care unit. All patients had at least 2 reconstruction procedures and multiple surgical debridements.</p> <p>Conclusion</p> <p>The functional outcome should be considered realistically before a salvage decision making for extremities with indeterminate prognosis.</p

Brown-Sequard syndrome after blunt cervical spine trauma: clinical and radiological correlations

The objective of this study was to describe clinical and radiological features of a series of patients presenting with Brown-Sequard syndrome after blunt spinal trauma and to determine whether a correlation exists between cervical plain films, CT, MRI and the clinical presentation and neurological outcome. A retrospective review was done of the medical records and analysis of clinical and radiological features of patients diagnosed of BSS after blunt cervical spine trauma and admitted to our hospital between 1995 and 2005. Ten patients were collected for study, three with upper- and seven with lower-cervical spine fracture. ASIA impairment scale and motor score were determined on admission and at last follow-up (6 months–9 years, mean 30 months). Patients with lower cervical spine fracture presented with laminar fracture ipsilateral to the side of cord injury in five out of six cases. T2-weighted hyperintensity was present in seven patients showing a close correlation with neurological deficit in terms of side and level but not with the severity of motor deficit. Patients with Brown-Sequard syndrome secondary to blunt cervical spine injury commonly presented T2-weighted hyperintensity in the clinically affected hemicord. A close correlation was observed between these signal changes in the MR studies and the neurologic level. Effacement of the anterior cervical subarachnoid space was present in all patients, standing as a highly sensitive but very nonspecific finding. In the present study, craniocaudal extent of T2-weighted hyperintensity of the cord failed to demonstrate a positive correlation with neurological impairment

Pharmacokinetic model of target-mediated disposition of thrombopoietin

Thrombopoietin, TPO, a 353 amino acid cytokine, is a primary regulator of platelet production that was cloned recently. A target-mediated (platelet receptors) pharmacokinetic model was developed to characterize the disposition of TPO. Receptor-mediated endocytosis was assigned as the major elimination pathway in the model. A nonspecific binding compartment was also incorporated into the model. TPO concentration vs time profiles from a published phase 1 and 2 clinical trial were used to apply this model. Noncompartmental analysis demonstrated that TPO exhibits nonlinear kinetics. The proposed model captured the concentration-time profiles relatively well. The first-order internalization rate constant was estimated as 0.1 h−1. The endogenous binding capacity was estimated as 164.0 pM. The second-order binding association constant (kon) was 0.055 h−1·pM−1 and the first-order dissociation constant (koff) was estimated as 2.5 h−1, rendering the equilibrium dissociation constant Kd as 45.5 pM. This model may be relevant to other therapeutic agents with receptor-mediated endocytotic disposition

Brown-Sequard syndrome revealing intradural thoracic disc herniation

Brown-Sequard syndrome (BSS) is a rare form of severe myelopathy characterised by a clinical picture reflecting hemisection of the spinal cord. This syndrome is mostly due to a penetrating injury to the spine but many other non-traumatic causes have been described. Intradural thoracic disc herniation (TDH) is one of the rare aetiologies of this syndrome. Despite progress in imaging techniques, diagnosis and treatment remain difficult. We retrospectively reviewed one of the largest reported series of six patients with BSS revealing intradural TDH between 2003 and 2007. There was a marked female predominance and the mean age was 44 years. Before surgery, half of the patients had a severe neurological deficit. The mean duration of symptoms until surgery was 8.5 months (range 0.5–24 months). Spine magnetic resonance imaging (MRI) or spine computer tomography scan showed calcified TDH between T5–T6 and T9–T10. The intradural location of the thoracic herniation was strongly suspected from the clinical data. All the patients underwent posterolateral transpedicular surgery with an operative microscope to open the dura mater. The intradural location of the herniation was overlooked in one case and the patient underwent a second procedure. The dura mater was carefully closed. Two patients’ condition worsened immediately after the surgery before slowly improving. All the other patients improved their neurological status immediately after the surgery and at 12 months follow-up. BSS with TDH on the spine MRI scan may be a warning symptom of the intradural location of the herniated disc. In such cases, spine surgeons are advised to use an operative magnification and to open the dura mater to avoid missing this potentially curable cause of severe myelopathy