The use of electrophysiological monitoring in the intraoperative management of intracranial aneurysms.
OBJECTIVES: Somatosensory evoked potentials (SSEPs) and brainstem auditory evoked potentials (BAEPs) have been increasingly utilised during surgery for intracranial aneurysms to identify cerebral ischaemia. Between July 1994 and April 1996, we surgically treated 70 aneurysms in 49 consecutive patients (58 operations) with the aid of intraoperative evoked potential monitoring. This study sought to evaluate the usefulness of SSEP and BAEP monitoring during intracranial aneurysm surgery. METHODS: Mean patient age was 51.9 (range 18-79) years. The sizes of the aneurysms were 3-4 mm (15), 5-9 mm (26), 10-14 mm (11), 15-19 mm (seven), 20-24 mm (six), and >25 mm (five). SSEPs were monitored in 58 procedures (100%) and BAEPs in 15 (26%). The neurological status of the patients was evaluated before and after surgery. RESULTS: Thirteen of the 58 procedures (22%) monitored with SSEPs had SSEP changes (12 transient, one persistent); 45 (78%) had no SSEP changes. Three of 15 patients (20%) monitored with BAEPs had changes (two transient, one persistent); 12 (80%) had no BAEP changes. Of the 14 patients with transient SSEP or BAEP changes, these changes resolved with adjustment or removal of aneurysm clips (nine), elevating MAP (four), or retractor adjustment (one). Mean time from precipitating event to electrophysiological change was 8.9 minutes (range 3-32), and the mean time for recovery of potentials in patients with transient changes was 20.2 minutes (range 3-60). Clinical outcome was excellent in 39 patients, good in five, and poor in three (two patients died), and was largely related to pretreatment grade. CONCLUSIONS: SSEPs and BAEPs are useful in preventing clinical neurological injury during surgery for intracranial aneurysms and in predicting which patients will have unfavourable outcomes. (+info)
Intraoperative transoesophageal echocardiography as an adjuvant to fluoroscopy during endovascular thoracic aortic repair.
OBJECTIVES: To define the utility of intraoperative transeophageal echocardiography (TEE) during endovascular thoracic aortic repair. DESIGN: Retrospective study. MATERIALS: Five patients underwent six transluminal endovascular stent-graft procedures for repair of thoracic aortic disease. METHODS: After induction of anaesthesia, a multiplane or biplane TEE probe was placed to obtain views of the diseased aorta. Both transverse and longitudinal planes of the aortic arch and descending thoracic aortic segments were imaged. The aortic pathology was confirmed by TEE and the proximal and distal extents of the intrathoracic lesion were defined. Doppler and colour-flow imaging was used to identify flow patterns through the aorta before and after stent-graft deployment. RESULTS: Visualisation and confirmation of the aortic pathology by ultrasonography was accomplished in all patients. TEE was able to confirm proper placement of the endograft relative to the aortic lesion after deployment and was able to confirm exclusion of blood flow into the aneurysm sacs. CONCLUSIONS: TEE may facilitate repair by confirming aortic pathology, identifying endograft placement, assessment of the adequacy of aneurysm sack isolation, as well as dynamic intraoperative cardiac assessment. (+info)
A policy of quality control assessment helps to reduce the risk of intraoperative stroke during carotid endarterectomy.
OBJECTIVES: A pilot study in our unit suggested that a combination of transcranial Doppler (TCD) plus completion angioscopy reduced incidence of intra-operative stroke (i.e. patients recovering from anaesthesia with a new deficit) during carotid endarterectomy (CEA). The aim of the current study was to see whether routine implementation of this policy was both feasible and associated with a continued reduction in the rate of intraoperative stroke (IOS). MATERIALS AND METHODS: Prospective study in 252 consecutive patients undergoing carotid endarterectomy between March 1995 and December 1996. RESULTS: Continuous TCD monitoring was possible in 229 patients (91%), while 238 patients (94%) underwent angioscopic examination. Overall, angioscopy identified an intimal flap requiring correction in six patients (2.5%), whilst intraluminal thrombus was removed in a further six patients (2.5%). No patient in this series recovered from anaesthesia with an IOS, but the rate of postoperative stroke was 2.8%. CONCLUSIONS: Our policy of TCD plus angioscopy has continued to contribute towards a sustained reduction in the risk of IOS following CEA, but requires access to reliable equipment and technical support. However, a policy of intraoperative quality control assessment may not necessarily alter the rate of postoperative stroke. (+info)
Intraoperative ultrasonography evaluation of posterior vertebral wall displacement in thoracolumbar fractures.
Intraoperative ultrasonography (IOUS) was used to evaluate the location and compressive effects of intraspinal fragments in thoracolumbar fractures and the efficacy of reduction maneuvers in patients operated on for isolated or attached intraspinal fragments or for global posterior wall disruption. Dynamic IOUS was used to evaluate the effects of traction and lordosis. Fifty-eight patients were evaluated using a 7.5 MHz ultrasound probe, including 27 treated by impaction, 19 by removal of apparently isolated fragments, and 12 by traction followed by lordosis for global posterior wall disruption. IOUS had limitations and problems caused by split fragments and residual pedicular attachments that can compromise intraoperative maneuvers. The risk of secondary displacement of isolated fragments treated by impaction was very high. In particular, the pinching effect produced by T-shaped fractures was commonly responsible for secondary displacement. IOUS evaluation of canal clearance after fragment removal was satisfactory, but did not provide quantitative data. IOUS was easier to perform and apparently more reliable than intraoperative myelography. The dynamic IOUS data suggest that, except for severely tilted fragments that are completely free or remain attached to a pedicle, residual discal attachments significantly influence the likelihood of successful reduction. (+info)
Intraoperative limb length measurement in total hip arthroplasty.
In order to evaluate the efficacy of intraoperative measurement of limb length inequality (LLI), we performed a prospective study on 64 patients who underwent unilateral total hip arthroplasty. The patients were divided into 2 groups. In Group I, the LLI was evaluated by the Shuck test, and in Group II by intraoperative measurement using a Steinman pin and an adjustable caliper. Preoperative LLIs assessed on radiographs averaged 1.18 cm in Group I and 0.37 cm in Group II. (+info)
Infected total hip arthroplasty--the value of intraoperative histology.
Intraoperative histology showed a sensitivity of 100% and a specificity of 98%. These results were better than those observed for the other tests evaluated. Our data provide evidence that intraoperative histology is useful tool in the diagnosis of infected total hip arthroplasty. (+info)
Non-invasive aortic blood flow measurement in infants during repair of craniosynostosis.
We have assessed the potential clinical benefit of a new echo-Doppler device (Dynemo 3000) which provides a continuous measure of aortic blood flow (ABF) using an aortic flowmeter and a paediatric oesophageal probe, during repair of craniosynostosis in infants under general anaesthesia. The data recorded included: ABFi (i = indexed to body surface area), stroke volume (SVi), systemic vascular resistance (TSVRi), pre-ejection period (PEP), left ventricular ejection time (LVET), mean arterial pressure (MAP), heart rate (HR) and central venous pressure (CVP). Data were collected: before (T1) and 3 min after skin incision (T2), at the time of maximal haemorrhage (T3) and at the end of the procedure (T4). Twelve infants (aged 7.0 (range 6-12) months) were included. ABFi, MAP and CVP were significantly lower at T3 compared with T1 (2.0 (0.8) vs 3.0 (0.8) litre min-1 m-2, 46.1 (5.8) vs 65.2 (8.9) mm Hg and 2.8 (1.6) vs 5.2 (2.1) mm Hg; P < 0.05). PEP/LVET ratio was significantly lower at T2 compared with T1 (0.25 (0.05) vs 0.30 (0.06)) and increased at T4 (0.36 (0.04); P < 0.05). These preliminary results suggest that this non-invasive ABF echo-Doppler device may be useful for continuous haemodynamic monitoring during a surgical procedure associated with haemorrhage in infants. (+info)
Surgery-induced insulin resistance in human patients: relation to glucose transport and utilization.
To investigate the underlying molecular mechanisms for surgery-induced insulin resistance in skeletal muscle, six otherwise healthy patients undergoing total hip replacement were studied before, during, and after surgery. Patients were studied under basal conditions and during physiological hyperinsulinemia (60 microU/ml). Biopsies of vastus lateralis muscle were used to measure GLUT-4 translocation, glucose transport, and glycogen synthase activities. Surgery reduced insulin-stimulated glucose disposal (P < 0.05) without altering the insulin-stimulated increase in glucose oxidation or suppression of endogenous glucose production. Preoperatively, insulin infusion increased plasma membrane GLUT-4 in all six subjects (P < 0.05), whereas insulin-stimulated GLUT-4 translocation only occurred in three patients postoperatively (not significant). Moreover, nonoxidative glucose disposal rates and basal levels of glycogen synthase activities in muscle were reduced postoperatively (P < 0.05). These findings demonstrate that peripheral insulin resistance develops immediately postoperatively and that this condition might be associated with perturbations in insulin-stimulated GLUT-4 translocation as well as nonoxidative glucose disposal, presumably at the level of glycogen synthesis. (+info)