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Results for “Monitoring, Intraoperative”

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At least 865 records · Page 48Linked to original sources

PubMed1998

Intraoperative assessment of microsurgery with three-dimensional optical coherence tomography.

PURPOSE: To evaluate three-dimensional optical coherence tomography (OCT) for use in the assessment of the microsurgical anastomoses of vessels and nerves. MATERIALS AND METHODS: OCT is an optical analogue of ultrasonography and is capable of imaging nontransparent biologic tissue by detecting backscattered infrared light. Cross-sectional in vitro images of rabbit and human vessels and nerves were obtained in as little as 125 msec at 10-micron resolution by using a solid-state laser as a light source. A surgical microscope was integrated with OCT to perform simultaneous imaging with en face visualization. Cross-sectional images were assembled to produce three-dimensional reconstructions of microsurgical specimens. RESULTS: Three-dimensional OCT reconstructions depicted the structure within an arterial anastomosis and helped identify sites of luminal obstruction. The longitudinal spatial orientation of individual nerve fascicles was tracked in three dimensions to identify changes in position. In vitro human arteries and nerves embedded in highly scattering tissue and not visible at microscopy were located and imaged with OCT at eight frames per second. CONCLUSION: The three-dimensional, micrometer-scale, diagnostic imaging capabilities of OCT permit rapid feedback for assessment of microsurgical procedures. OCT technology can be readily integrated with surgical microscopes and has potential for intraoperative monitoring to improve patient outcome.

Anastomosis, Surgical↗

PubMed2001

Anesthetic management of renal cell carcinoma with inferior vena caval extension.

We present a case of a patient with renal cell carcinoma extending into the inferior vena cava. Preoperative diagnosis was facilitated by transthoracic and transesophageal echocardiography (TEE), and inferior venacavography. Intraoperatively, monitoring with continuous TEE was used. Preparation was made for cardiopulmonary bypass but surgery was successfully completed using extracorporeal venous shunting. We discuss the important aspects of preoperative diagnosis and the intraoperative anesthetic management of this case.

Anesthesia↗

PubMed1996

Combined carotid endarterectomy, innominate artery reconstruction, and coronary artery bypass grafting: case report.

Neurologic injury is one of the most devastating complications of combined carotid and cardiac procedures. Although the cause of the deficit is usually embolic, the exact cause is often not apparent at the time of surgery. We present a complex case of combined carotid endarterectomy, innominate artery reconstruction, and coronary artery bypass procedures in which intraoperative monitoring with somatosensory evoked potentials and transcranial Doppler ultrasonography combined with postoperative acetazolamide single photon emission computed tomographic scans was used to correlate intraoperative events with cerebral activity and functional results. Although computed tomographic scan, magnetic resonance imaging, and clinical evaluation were negative for any evidence of stroke, the patient exhibited subtle postoperative changes in neuropsychologic function. These changes were correlated with intraoperative microemboli detected by transcranial Doppler monitoring, and postoperative acetazolamide single photon emission computed tomographic scanning, which revealed bilateral cortical defects.

Acetazolamide↗

PubMed1998

[Continuous monitoring of the recurrent laryngeal nerve].

A new "all in one" sensing device for tracing and continuous intraoperative monitoring of the recurrent laryngeal nerve during thyroid surgery is described. The system, based on a double ballooned endotracheal tube, is atraumatic, easy to use and sensitive even to imminent trauma to the nerves. The most striking feature of this instrument is that it operates outside the sterile operating field and truly monitors continuously throughout the operation.

Adult↗

PubMedDate not supplied

[The perioperative diagnosis of cerebral ischemia during reconstructive operations on the carotid arteries (initial experience in using transcranial oximetry)].

Intraoperative monitoring of cerebral ischemia during surgery on the brachiocephalic arteries is carried out by several methods: transcranial dopplerography, electroencephalography, recording of the somatosensory evoked potentials, puncture measurement of intravascular pressure, etc. However, not all these methods are sufficiently informative, reliable, and safe. One of the methods meeting these requirements is noninvasive cerebral oximetry. The study was carried out by the Invos-3100 device (Somanetics, USA). The method of cerebral oximetry is based on optic spectroscopy using infrared light in the 650-1100 nm waveband. Monitoring was carried out in 34 patients with involvement of the brachiocephalic arteries. The results persuasively prove high informative value and safety of the method.

Brain↗

PubMed1994

Facial nerve monitoring in skull base surgery.

The purpose of this work was to compare pre- and post-operative facial nerve function between unmonitored and monitored cases of skull base lesions. The study involved 32 patients suffering from lateral skull base tumours (10 unmonitored and 22 monitored). Facial nerve function was monitored intraoperatively by an acoustic facial electromyographic system (NIM-2). Post-operative facial function was graded according to the House-Brackmann scale. In the group of monitored cases, facial nerve function was normal (Grade 1 or 2) in 79 per cent of the patients, while the unmonitored patients showed normal function in only 50 per cent of the cases. These results confirm previous observations that audible evoked electromyographic monitoring significantly reduces permanent facial nerve dysfunction.

Adult↗

PubMed1990

Electrophysiologic evaluation and monitoring of spinal cord and root function.

The spinal cord can be monitored intraoperatively with somatosensory evoked potentials. Although this is only a posterior column test, it is sensitive to most acute cord impairment. Techniques have become standardized and include monitoring from scalp or around the spinal cord itself. Motor evoked responses are currently under investigation for possible OR use, and they may someday supersede somatosensory testing as the monitoring tool of choice.

Electrodiagnosis↗

PubMed2003

Reliability of perioperative SSEP recordings in spine surgery.

OBJECTIVE: The reproducibility and clinical reliability of perioperative somatosensory-evoked potentials (SSEP) were prospectively evaluated in uneventful scoliosis surgery. The influence of anesthesia owing to induction of total intravenous anesthesia (TIVA) upon preoperative SSEP and the variability of intraoperative SSEP were calculated. The potential effect of spine surgery was assessed by comparing pre- to postoperative SSEP. METHODS: A total of 2,143 pre-, intra- and postoperative tibial and median SSEP recorded in 25 patients undergoing spine surgery owing to idiopathic scoliosis were analyzed. The anesthesia protocol consisted of a computerized target controlled infusion (TCI) device for propofol and intravenous application of an opioid. RESULTS: Anesthesia induced a significant and comparable prolongation of the tibial SSEP onset, P40 and P60 latencies, while the N50 latency was less changed. Throughout anesthesia, latencies of median (onset, N20, P25 and N35) and tibial (onset, P40, N50 and P60) SSEP showed mean variations of less than 6%. The intraoperative SSEP amplitudes were less stable with a relative standard deviation of 30-40%. In uneventful spine surgery, the postoperative tibial SSEP were not significantly changed in comparison to preoperative recordings. CONCLUSIONS: By using a standardized anesthesia protocol, the impact of anesthesia on preoperative SSEP can be predicted. Furthermore, the controlled application of sedatives and analgesics allows recording of stable SSEP parameters for intraoperative monitoring purposes. As in uneventful spine surgery pre- to postoperative SSEP are unchanged the latter comparison can be applied as an additional perioperative neuromonitoring procedure to assess the influence of spine surgery or other invasive interventions on spinal cord function.

Adolescent↗

PubMed1988

Intraoperative somatosensory potential monitoring. A clinical analysis of 127 surgical procedures.

During 127 operations for the correction of spinal deformities the spinal cord function was controlled by intraoperative monitoring. Cortical somatosensory evoked potentials (CSEP) were obtained by bilateral stimulation of the posterior tibial nerves at the ankle and recorded from electrodes at Fz-Cz. In addition, unilateral median nerve stimulation at the wrist was carried out to act as a control. Six cases with significant intraoperative alterations in wave-form and their postoperative neurologic status are described in detail. EP monitoring permits continuous monitoring of the patient for the total duration of operation and is therefore superior to the wake-up test. This method is particularly advisable for operations carried out in hypotensive anaesthesia as well as for postoperative control.

Adolescent↗

PubMed2005

Revisiting lithium-associated hyperparathyroidism in the era of intraoperative parathyroid hormone monitoring.

BACKGROUND: Chronic lithium therapy may cause hyperparathyroidism (HPT). The utility of intraoperative parathyroid hormone monitoring (IOPTH) in these patients is unknown. The authors' hypothesis was that multiglandular disease is more common in these patients, and the ability of IOPTH to predict cure may be limited. METHODS: Twelve patients had HPT during chronic lithium therapy and underwent parathyroidectomy with IOPTH. Criteria for curative resection were a decrease > or =50% from baseline and into the normal range. Calcium and PTH levels were measured during follow-up. RESULTS: Preoperatively, mean calcium was 11.0 +/- 0.1 mg/dL, and PTH was 116 +/- 14 pg/mL. Fifty percent of patients had multiglandular disease confirmed by IOPTH levels. Mean IOPTH decrease from baseline was 74 +/- 4%. Although 10 of 12 patients met criteria for curative resection, only 8 remain normocalcemic. The 2 patients who did not meet criteria remain normocalcemic. Mean postoperative calcium for all patients was 9.5 +/- 0.2 mg/dL. Of the 10 normocalcemic patients, 4 also have hyperparathormonemia (mean PTH, 119 +/- 19 pg/mL). CONCLUSIONS: The incidence of multiglandular disease in HPT after chronic lithium exposure is higher than standard HPT. The ability of IOPTH to predict durable normocalcemia is limited. Bilateral neck exploration should be considered for these patients regardless of whether IOPTH monitoring is used.

Adult↗

PubMed2005

Multi-modality neurophysiological monitoring during surgery for adult tethered cord syndrome.

During complex microneurosurgery performed in patients with tethered cord syndrome, the conus medullaris and the roots that innervate the lower limbs, bladder and bowel are potentially exposed to damage. The aim of multimodality intraoperative monitoring (IOM) is to reduce the risk of inadvertent injury of neural tissue. We simultaneously record tibial nerve somatosensory evoked potentials (SSEPs) from the scalp and free run electromyography (EMG) of limb muscles supplied by L2 to S2 roots, anal and urethral sphincters. We also identify critical neural structures in the operative field, including the conus and exiting nerve roots, with a nerve stimulator to evoke EMG. SSEPs assess the sensory pathways mainly mediated by the S1 roots. Continuous EMG provides the surgeon with immediate auditory feedback resulting from irritative discharges triggered by manipulation of nerve fibres. Microstimulation can distinguish the filum terminale, scar tissue and invasive tumors from functional neural tissue, thus minimizing the risk of iatrogenic injury. Overall multimodality IOM proves a valuable adjunct to microneurosurgery of the lumbosacral spine.

Adult↗

PubMed2005

Cerebral hyperperfusion after carotid endarterectomy is associated with preoperative hemodynamic impairment and intraoperative cerebral ischemia.

The aim of this study was to investigate whether postoperative hyperperfusion is associated with preoperative cerebral hemodynamic impairment due to chronic ischemia and with acute cerebral ischemia during clamping of the internal carotid artery (ICA) during carotid endarterectomy (CEA). Transcranial cerebral oxygen saturation (SO2) was monitored intraoperatively using near-infrared spectroscopy in 89 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were also measured using single photon emission computed tomography (SPECT) before CEA. In addition, CBF was measured immediately after CEA and on the third postoperative day. Hyperperfusion (CBF increase>100% compared with preoperative values) was observed immediately after CEA in 10 of 18 patients (56%) with reduced preoperative CVR. Also, post-CEA hyperperfusion was observed in nine of 16 patients (56%) whose SO2 during clamping of the ICA decreased to less than 90% of the preclamping value. Logistic regression analysis showed that reduced preoperative CVR and reduced SO2 during ICA clamping were significant independent predictors of the development of hyperperfusion immediately after CEA. In fact, all patients with reduced preoperative CVR and reduced SO2 during ICA clamping developed post-CEA hyperperfusion, and two of these patients developed cerebral hyperperfusion syndrome. These data suggest that development of cerebral hyperperfusion after CEA is associated with preoperative hemodynamic impairment and intraoperative cerebral ischemia.

Aged↗

PubMed1997

Using transcranial duplex sonography for monitoring vessel patency during surgery for intracranial aneurysms.

This article reports a method for reliable intraoperative monitoring of blood flow velocities in the basal cerebral arteries during clipping of intracerebral aneurysms. Transcranial color-coded duplex sonography provides practical integration of transcranial Doppler technology with real-time imaging capabilities through the intact human skull. With a computerized sonography system equipped with a 2.5-MHz probe in 50 healthy volunteers, the contralateral internal carotid artery, A1 and A2, as well as M1 and P1 vessels were identified and measured in most patients. In 13 patients undergoing dipping of intracranial aneurysms, the technique successfully imaged 12; it allowed definitive identification of vessels potentially threatened by clipping and not fully visible to the surgeon. Data were easily comparable to preoperative data. This noninvasive, repeatable neuroimaging technique provides useful intraoperative information about intracranial hemodynamics during dipping of intracranial aneurysms.

Adult↗

PubMed1986

Recurrent versus residual carotid stenosis. Incidence detected by Doppler ultrasound.

A sterile Doppler probe was used for intraoperative monitoring of the integrity of carotid endarterectomy of 125 vessels of 107 patients. Our objective was to reduce the contribution of residual carotid lesions to recurrent stenosis, which was evaluated by Doppler spectrum analysis in the early (less than 3 months, 66 arteries) and late (3-77 months, mean 32 months, 47 arteries) postoperative period. Intraoperative Doppler monitoring detected residual occlusion in six (4.8%) external carotid arteries and stenosis in ten (8.0%) internal carotid arteries permitting selected arteriography and correction of all significant lesions. Follow-up revealed one (1.5%) asymptomatic common carotid occlusion at 6 weeks and three (6.4%) asymptomatic internal carotid stenoses at 6, 10 and 25 months after operation. When compared to previous published experience, these results suggest that intraoperative correction of residual carotid obstruction detected by Doppler ultrasound may reduce the incidence of postoperative "recurrent" carotid stenosis.

Adult↗

PubMed1993

Facial nerve monitoring in surgery for congenital auricular atresia.

Surgery for congenital auricular atresia places the facial nerve at risk because of its potential aberrancy; iatrogenic facial paralysis is a well-known potential risk. Five cases of congenital auricular atresia are presented. All patients had intraoperative monitoring of the facial nerve. The facial nerve was found to be abnormally displaced, usually due to hypoplasia of the tympanic ring. Preoperative and postoperative facial nerve function was unchanged by surgery. Facial nerve monitoring is an important adjunct in congenital ear surgery because it allows for early and precise identification of the nerve in the absence of normal surgical landmarks and provides for continuous monitoring of the nerve.

Adult↗

PubMed2002

Metabolism in pedicled and free TRAM flaps: a comparison using the microdialysis technique.

The most common complication in flap surgery is of a circulatory nature. Impeded blood flow leads to altered metabolism in the tissue. Possible metabolic differences between different zones of the transverse rectus abdominis muscle (TRAM) flap were studied and the metabolism of pedicled and free TRAM flaps was compared intraoperatively and postoperatively. The method used was microdialysis, which is a useful technique for following local metabolic changes continuously in various tissues.Twenty-two patients with a pedicled or free TRAM flap were monitored using the microdialysis technique. Two microdialysis catheters were placed subcutaneously in the flap (zone I and zone II), and a third one was placed subcutaneously in the flank to serve as a control. The flaps were monitored intraoperatively and postoperatively for 3 days with repeated analyses of extracellular glucose, lactate, and glycerol concentrations. An additional analysis of pyruvate was performed in some patients to calculate the lactate-to-pyruvate ratio. This study showed that glucose, lactate, and glycerol change in a characteristic way when complete ischemia (i.e., complete inhibition of the blood circulation) is present. A slower stabilization with prolonged metabolic signs of ischemia, such as lower glucose and higher lactate and glycerol concentrations, was seen in zone II compared with zone I, and more pronounced metabolic signs of ischemia, but with a faster recovery, were detected in the free TRAM flap group than in the pedicled TRAM flap group. The fact that the metabolites returned to normal earlier in free flaps than in pedicled flaps may indicate that free TRAM flaps sustain less ischemic damage because of better and more vigorous perfusion.

Abdominal Muscles↗

PubMed2001

[Evolution and change of strategy in carotid artery surgery in Debrecen].

In the 1st Department of Surgery, in Debrecen, operations on supraaortic arteries are done, since 1985. In the first five years, sporadically, only 2-3 carotid reconstruction have been done. Between 1990-1996 the number of these operations were about 20 per year, although the number of postoperative complications were around 1%. The number of operative interventions on the carotid region were doubled in 1997 and from 1999 were four times more. The authors analysed the data of the patients, accumulated in the last 6 years. In this period 258 operations were done. Unilateral significant stenosis found in 159 (61%) patients and bilateral serious stenosis or unilateral occlusion in 99 (38.6%) patients. 22.4% of the patients who were operated in our department, were waiting for coronary revascularisational operation because of angina pectoris. 5.4% suffered from vitium and were later undergone cardiac valve operation. By 24% of the patients later, electively we performed reconstructional vascular operation on the lower limbs. The base of preoperative examinations was cerebrovascular circulational insufficiency by almost half of the patients (46.1%). Beside anaesthesiological basic examinations, detailed diagnostics (exercised EKG, TTE, coronariography, Holter monitor) were done. In the overwhelming majority of the operations we used the eversion technique. The surgical interventions were performed in every case using non-invasive haemodynamical monitor (transoesophageal doppler ODM-II). Our results meet the requirement of the national and international standouts. These results prove, that with the help of comprehensive pre-operational examinations and preparation, intraoperative monitor and having up-to-date, precise operational technique, the international standards can be sustained even treating patients with such a high risk.

Adult↗

PubMed2002

Video-based system for intraoperative facial nerve monitoring: comparison with electromyography.

OBJECTIVE: To validate a recently developed intraoperative facial nerve monitoring system that is based on video control of facial movements. STUDY DESIGN: In a single-subject design study, involving 15 otoneurosurgical patients, the relationship between intensity of neural stimulation, facial movements, and electrophysiologic voltage were measured. The analysis was performed by measuring the ipsilateral oral commissure displacement in relation to different levels of current administered to the nerve during surgical procedures. SETTING: Electromyography and video system intraoperative facial nerve monitoring. PATIENTS: 15 patients (9 men, 6 women; mean age, 61 yr) undergoing a translabyrinthine approach for removal of acoustic neuroma. RESULTS: Electromyography showed slightly greater sensitivity. With regard to the stimulation-response ratio, facial movement and electromyographic amplitude showed very similar responses. CONCLUSIONS: The video system was considered useful in terms of validity and reliability. Furthermore, the authors' surgical experience showed some limitations of electromyography, especially in terms of electrical artifact during cauterization, totally masking the electrophysiologic monitoring.

Electric Stimulation↗