A 72-h sedated porcine model of traumatic spinal cord injury.

Introduction: There is an increasing focus on the prevention of secondary injuries following traumatic spinal cord injury (TSCI), especially through improvement of spinal cord perfusion and immunological modulation. Such therapeutic strategies require translational and controlled animal models of disease progression of the acute phases of human TSCI. Research question: Is it possible to establish a 72-h sedated porcine model of incomplete thoracic TSCI, enabling controlled use of continuous, invasive, and non-invasive modalities during the entire sub-acute phase of TSCI? Material and methods: A sham-controlled trial was conducted to establish the model, and 10 animals were assigned to either sham or TSCI. All animals underwent a laminectomy, and animals in the TSCI group were subjected to a weight-drop injury. Animals were then kept sedated for 72 h. The amount of injury was assessed by ex-vivo measures MRI-based fiber tractography, histology and immunohistochemistry. Results: In all animals, we were successful in maintaining sedation for 72 h without comprising vital physiological parameters. The MRI-based fiber tractography showed that all TSCI animals revealed a break in the integrity of spinal neurons, whereas histology demonstrated no transversal sections of the spine with complete injury. Notably, some animals displayed signs of secondary ischemic tissue in the cranial and caudal sections. Discussion and conclusions: This study succeeded in producing a porcine model of incomplete TSCI, which was physiologically stable up to 72 h. We believe that this TSCI model will constitute a potential translational model to study the pathophysiology secondary to TSCI in humans.

Optimal reverse trendelenburg position in patients undergoing craniotomy for cerebral tumors.

OBJECT: To the authors' knowledge, repeated measurements of intracranial pressure (ICP), cerebral perfusion pressure (CPP), and the degree of dural tension during different positions on the operating table (reverse Trendelenburg position [rTp]) have not been studied in patients undergoing craniotomy. METHODS: In the present study 53 patients with supratentorial cerebral tumors who underwent craniotomy in the supine position were included. Subdural ICP, mean arterial blood pressure (MABP), CPP, and jugular bulb (JB) pressure were recorded, and the degree of dural tension was analyzed while patients were in the neutral operating position and at 5, 10, and 15 degrees rTp. The optimal operating position was defined as the one at which subdural ICP was as low as possible, and CPP was greater than or equal to 60 mm Hg or as high as possible. Subdural ICP, MABP, and JB pressure decreased significantly after each 5 degrres change in rTp compared with the preceding position. Dural tension decreased significantly up to 10 degrees rTp, but was unchanged at 15 degrees rTp. At 5 degrees rTp CPP remained unchanged, but it decreased significantly during 10 and 15 degrees rTp. The optimal position in the majority of patients was determined to be 15 degrees rTp. CONCLUSIONS: Before opening the dura mater for craniotomy, repeated measurements of ICP and CPP, in the neutral position and at 5, 10, and 15 degrees rTp, provide valuable information regarding the optimal level of ICP and CPP.

The effects of 10 degrees reverse Trendelenburg position on subdural intracranial pressure and cerebral perfusion pressure in patients subjected to craniotomy for cerebral aneurysm.

The aim of the current study was to examine the effects of 10 degrees reverse Trendelenburg position (rTp) on subdural intracranial pressure (ICP), cerebral perfusion pressure (CPP), and dural tension. Additionally, the relationship between preoperative Hunt and Hess (H and H) grade and the subdural ICP in patients scheduled for cerebral aneurysm surgery was investigated. Twenty-eight consecutive patients with a cerebral aneurysm were subjected to craniotomy in propofol/fentanyl or propofol/remifentanil anesthesia. Subdural ICP was measured after opening of the bone flap and exposure of dura. After reference measurements of subdural ICP and mean arterial blood pressure (MABP), the measurements were repeated during 10 degrees rTp. No significant differences between the anesthetic groups were disclosed. During 10 degrees rTp, a significant decrease in MABP, ICP, and jugular bulb pressure was observed whereas CPP remained unchanged. In H and H 0 patients (unruptured aneurysm), the ICP decreased from 2.9 +/- 2.6 mmHg to 0.4 +/- 2.2 mmHg at 10 degrees rTp. In H and H I to II patients, the ICP decreased from 9.3 +/- 3.8 mmHg to 4.6 +/- 3.3 mmHg at 10 degrees rTp. A significant difference in the mean baseline subdural ICP and DeltaICP (change in ICP) was found between patients with unruptured aneurysm and patients with subarachnoid hemorrhage (H&H I and II). Furthermore, the relationship between the subdural ICP at neutral position and DeltaICP was significant. In patients without intracranial hypertension, 10 degrees rTp decreases subdural ICP and dural tension in patients with ruptured as well as patients with unruptured cerebral aneurysm; CPP is unchanged.