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Results for “Monitoring, Intraoperative”

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At least 829 records · Page 46Linked to original sources

PubMed2004

Transcranial motor evoked potentials during basilar artery aneurysm surgery: technique application for 30 consecutive patients.

OBJECTIVE: Microsurgical clipping of basilar artery aneurysms carries a risk of neurological compromise resulting from midbrain or thalamic ischemia. Somatosensory evoked potential (SSEP) monitoring and electroencephalography are the standard techniques for assessing the level of cerebroprotective anesthesia and monitoring ischemia during temporary occlusion or after permanent clipping. Transcranial motor evoked potential (TcMEP) monitoring was added to determine whether this modality improved intraoperative monitoring. METHODS: Combined SSEP/electroencephalographic/TcMEP monitoring was used for 30 consecutive patients with basilar artery apex aneurysms in the past 1.5 years. Voltage thresholds were recorded before, during, and after aneurysm treatment for the last 10 patients. RESULTS: All 30 patients underwent an orbitozygomatic craniotomy for clipping (28 patients), wrapping (1 patient), or superficial temporal artery-superior cerebellar artery bypass (1 patient). Electrophysiological changes occurred for 10 patients (33%), elicited by temporary clipping (6 patients), permanent clipping (3 patients), or retraction (1 patient). Isolated SSEP changes were observed for one patient, isolated TcMEP changes for five patients, and changes in both TcMEPs and SSEPs for four patients. Among patients with simultaneous changes, TcMEP abnormalities were more robust and occurred earlier than SSEP abnormalities. Impaired motor conduction was detected first with an increase in the voltage threshold (from 206 +/- 22 to 410 +/- 49 V, P < 0.05, n = 3) and then with loss of TcMEP responses. SSEP and TcMEP signals returned to baseline values for all patients after corrective measures were taken. CONCLUSION: TcMEP monitoring can be safely and easily added to traditional neurophysiological monitoring during basilar artery aneurysm surgery. These results suggest that TcMEPs may be more sensitive than SSEPs to basilar artery and perforating artery ischemia. This additional intraoperative information might minimize the incidence of ischemic complications attributable to prolonged temporary occlusion or inadvertent perforator occlusion.

Adult↗

PubMed1992

Intraoperative angiography and endovascular ultrasound imaging.

Endovascular ultrasound imaging is a new technique that can be used to monitor intraoperatively the effects of balloon angioplasty or to inspect the quality of vascular reconstruction, such as endarterectomy or bypass surgery. The technique is based on high frequency ultrasonic imaging (30-40 MHz) using a rotating single element transducer mounted in an 8F catheter tip, providing 360 degrees cross-sectional real time images. The clinical application is based on the high correlation between the ultrasonic images and the histological characteristics of the corresponding vessel wall tissue and lumen geometry, as has been established in previous in vitro studies. Endovascular ultrasound assessment of percutaneous angioplasty procedures or intraoperative vascular reconstruction has become an adjunct to angiographic and/or angioscopic monitoring.

Angiography↗

PubMed2006

A pitfall in ligation of intrahepatic shunting after Fontan type operation.

An 8-year-old boy experienced progressive cyanosis after a Fontan type operation. Under the guidance of intraoperative color Doppler we performed a transabdominal ligation of the accessory hepatic veins which drained into a common atrium. Reoperation was needed through a median sternotomy to eliminate residual shunting. Although intraoperative Doppler is useful to aid in the ligation of accessory veins while portal hypertension is monitored, intraoperative angiogram serves better to ensure the elimination of intrahepatic shunting in a transabdominal approach.

Angiography↗

PubMed1984

Intraoperative evoked potential monitoring of the spinal cord. A restricted filter, scalp method during Harrington instrumentation for scoliosis.

Intraoperative monitoring of somatosensory evoked potentials (EPs) can improve the margin of safety during surgery around the spine. Several methods are available. The authors report their experience in monitoring 65 patients who underwent Harrington instrumentation and spinal fusion for correction of scoliosis. They studied the effects of changes in stimulating and recording parameters, seeking ways to reduce noise and variability in the EP signal. The authors were able to improve the quality of the monitoring records significantly by closer spacing of the scalp electrodes, bipolar rather than referential recording, faster rates of stimulation, and greater low-frequency filtering. The technique seems to be safe, easily performed, reproducible, and relatively inexpensive. It has produced no false-negative results to date, and it significantly reduced the incidence of false-positive results (false alarms) as compared with previously described techniques.

Adolescent↗

PubMed2004

Monitoring of the lateral spread response in the endovascular treatment of a hemifacial spasm caused by an unruptured vertebral artery aneurysm. Case report.

The lateral spread response (LSR) is used in the electrophysiological diagnosis of a hemifacial spasm or for monitoring during microvascular decompression. The authors used LSRs for intraoperative monitoring during endovascular surgery in a rare case of vertebral artery (VA) aneurysm that caused intractable hemifacial spasm. A 49-year-old woman presented with a right hemifacial spasm that had persisted for 9 months. No other clinical symptom was observed. Vertebral artery angiography revealed a saccular aneurysm of the right VA. Magnetic resonance (MR) imaging demonstrated that the aneurysm was compressing the root exit zone of the right facial nerve. Endovascular treatment of the VA aneurysm was performed while monitoring the patient's LSRs. During occlusion of the VA at sites distal and proximal to the aneurysm, the LSRs temporarily disappeared and then reappeared with a higher amplitude than those measured preceding their disappearance. The hemifacial spasm alleviated gradually and disappeared completely 6 months after treatment. The LSRs changed in parallel with the improvement in the patient's hemifacial spasms and eventually disappeared. No recurrence of symptoms has been noticed as of 18 months postoperatively. This is the first report of the use of LSR monitoring during endovascular surgery for an intracranial aneurysm that causes hemifacial spasm. Intraoperative and postoperative changes in the LSRs provided useful information regarding the pathophysiology of hemifacial spasm.

Electric Stimulation↗

PubMed1993

Intraoperative facial nerve monitoring in posterior fossa acoustic neuroma surgery.

Intraoperative facial nerve monitoring has become an indispensable tool during cerebellopontine angle surgery. Ninety-seven patients underwent surgical removal of an acoustic neurinoma with the use of a pneumatic sensor monitoring between January 1, 1986, and December 31, 1990. In the early postoperative period, a normal or near-normal facial function (grades I and II) was achieved in 86% of the patients, a moderate dysfunction (grade III) was present in 7%, and a total or severe dysfunction (grades V or VI) was present in 6%. Normal function at 1 year was achieved in 90.5% of the patients, 4% were grade II, a moderate dysfunction (grade III) was present in 2%, and 3% showed a total or severe dysfunction (grade V and VI). The incidence of normal function decreased with tumor size, with an occurrence rate of 100%, 94%, and 91% in small, medium, and large tumors, respectively. In eight consecutive patients, all responses detected by the monitoring during the operation were collected and analyzed according to intraoperative events. Analysis of the results indicate that 95% of the 316 mechanically induced stimulations were of small or extremely small amplitude, and only 5% were of moderate amplitude. A medial-to-lateral strategy of dissection, preservation of the arachnoid veil over the facial nerve, a control by the monitoring of the amount of traction, and a more widespread use of sharp dissection were the major approaches to reduce surgical trauma during dissection.

Adult↗

PubMed2004

Effects of anesthetic agents and physiologic changes on intraoperative motor evoked potentials.

Motor evoked potentials (MEPs) have shown promise as a valuable tool for monitoring intraoperative motor tract function and reducing postoperative plegia. MEP monitoring has been reported to contribute to deficit prevention during resection of tumors adjacent to motor structures in the cerebral cortex and spine, and in detecting spinal ischemia during thoracic aortic reconstruction. Many commonly used anesthetic agents have long been known to depress MEP responses and reduce MEP specificity for motor injury detection. Although new stimulation techniques have broadened the spectrum of anesthetics that can be used during MEP monitoring, certain agents continue to have dose-dependent effects on MEP reliability. Understanding the effects of anesthetic agents and physiologic alterations on MEPs is imperative to increasing the acceptance and application of this technique in the prevention of intraoperative motor tract injury. This review is intended as an overview of the effects of anesthetics and physiology on the reproducibility of intraoperative myogenic MEP responses, rather than an analysis of the sensitivity and specificity of this monitoring method in the prevention of motor injury.

Anesthetics↗

PubMed2004

Intra-operative monitoring in scoliosis surgery with multi-pulse cortical stimuli and desflurane anesthesia.

STUDY DESIGN: Prospective, observational study. SETTING: Country General Hospital, Singapore. OBJECTIVE: Intraoperative monitoring (IOM) with motor-evoked potentials (MEPs) assesses the integrity of cortical spinal tracts during scoliosis surgery. MEPs are sensitive to the effects of inhalational anesthetic agents. We evaluate the use of desflurane in combination with multipulse cortical stimulation in this study. METHODS: In all, 10 consecutive neurologically normal subjects underwent scoliosis surgery with desflurane anesthesia (0.5 maximum alveolar concentration) and five pulse cortical stimulation (250 Hz) from two stimulators in parallel configuration, delivering a maximum intensity of 160 mA. RESULTS: Consistent MEPs were obtained from the abductor hallucis and tibialis anterior in nine of ten and five of five of subjects, respectively. Baseline coefficients of variations were below 16% for both muscles. CONCLUSION: This combination of anesthetic and stimulation protocols is efficacious for IOM during spinal cord surgery. Our findings support the use of desflurane for successful acquisition of MEPs during scoliois surgery as an alternative anesthetic regime.

Adolescent↗

PubMed2000

[Neuroimaging and neurofunctional diagnosis of brain tumors].

Recent advances in diagnostic modalities such as computerized tomography(CT-scan), magnetic resonance imaging(MRI), and electrophysiological examination including EEG, SEP, ABR, have facilitated the diagnosis of relatively small brain tumors, while refinement in microsurgical techniques with the aid of intraoperative echo-sonography, endoscopy, navigation surgery and application of intraoperative monitoring of brain function, have facilitated precise diagnosis and safe surgery for brain tumors. This paper presents the preoperative, intraoperative, and postoperative usefulness of these modalities in treating brain tumors.

Brain Neoplasms↗

PubMed1986

Anorectal pressure monitoring during surgery on sacral lipomeningocele. Case report.

Intraoperative monitoring of anorectal pressure was used in a case of sacral lipomeningocele accompanied by congenital dermal sinus to protect the physiological function of the anorectal sphincters. This monitoring system consists of a manometric anorectal balloon and neural electrical stimulation. The system was able to differentiate functioning neural structures from surrounding tissues during the operation.

Anus Diseases↗

PubMed1998

Role of a perivascular ultrasonic micro-flow probe in aneurysm surgery.

There are various intraoperative monitoring devices available today for helping the neurosurgeons the progress of the intracranial aneurysm surgery. Till now the intraoperative ultrasonic blood flow probes has been used only in vascular, cardiac, and transplant surgery. In the University of Illinois at Chicago we have been able to use the same technology in various neurovascular surgeries. We describe the use of the ultrasonic perivascular blood flow probes in patients operated for clipping of intracranial aneurysm. The use of this perivascular micro-flow probe and its importance in cerebral aneurysm will be discussed.

Brain↗

PubMed1998

Intraoperative adjuncts of spinal cord protection.

Immediate neurological deficits as a complication of aortic surgery occur as the direct result of hypoxia, related to the acute deprivation of spinal cord blood supply inflicted by prolonged aortic cross-clamping (AXC). The etiology of spinal cord ischemia constitutes a series of progressive interdependent events which include proximal hypertension, increase in cerebrospinal fluid pressure, perioperative hypotension, inadequate perfusion to critical intercostal or lumbar vessels, extent of aortic pathology and duration of AXC. Several intraoperative interventions and strategies, which address the multifactorial nature of cord injury, are presented by the authors. Of critical importance is the role of adequate distal aortic perfusion, with either left atrium-femoral artery (LA-FA) bypass or arterial-arterial passive shunts, to control both central hypertension, through proximal unloading, and hypotension distal to AXC. Equally crucial is the increase in CSF pressure, secondary to proximal hypertension, which acts antagonistically to distal aortic pressure in regulating spinal cord perfusion pressure (SCPP). Cerebrospinal fluid drainage (CSFD) reduces CSF pressure to offset SCPP to favor cord perfusion. Pharmacological agents, such as papaverine and steroids in combination with CSFD, produce a synergistic benefit of extending the time interval of safe AXC. Encouraging results have also been realized with circulatory arrest and profound hypothermia which reduce oxygen demand of neural tissues and extend the safe duration of AXC interval. The use of distal bypass is most effective with CSFD as an integral component of a multimodality approach, which also incorporates the intraoperative monitoring of somatosensory evoked potentials (SSEP), to detect the onset of spinal cord ischemia and assess the adequacy of distal aortic perfusion and disposition of critical segmental vessels.

Aortic Aneurysm, Abdominal↗

PubMed2006

Combined use of adamkiewicz artery demonstration and motor-evoked potentials in descending and thoracoabdominal repair.

BACKGROUND: We retrospectively reviewed the outcome of distal descending aortic and thoracoabdominal aortic repair with preoperative identification of the Adamkiewicz artery by magnetic resonance angiography and intraoperative monitoring of transcranial motor-evoked potentials. METHODS: We began combined use of demonstration of the Adamkiewicz artery and intraoperative recording of motor-evoked potentials for prevention of spinal cord complications in descending and thoracoabdominal aortic aneurysm repair in 1998. Ninety-two consecutive patients were studied, with descending aneurysm in 53 and thoracoabdominal aneurysm in 39 patients. The repair was performed through a left thoracic or thoracoabdominal incision, using partial cardiopulmonary bypass to prevent spinal cord injury. Magnetic resonance angiography revealed the Adamkiewicz artery in 70.7% of cases. During surgery, spinal cord ischemia was monitored using motor-evoked potentials. Anastomoses were performed using a segmental clamp technique to reduce spinal cord ischemic time. Based on the findings of magnetic resonance angiography and motor-evoked potentials, the Adamkiewicz artery and other relevant intercostals and lumbar arteries were revascularized or preserved, or both. RESULTS: The mean durations of partial cardiopulmonary bypass, cross-clamping, and surgery, respectively, were 144.4 +/- 232.2, 106.0 +/- 65.5, and 411.8 +/- 170.7 minutes. Three hospital deaths (3.3%) occurred in patients with a thoracoabdominal aortic aneurysm. Motor-evoked potentials changed in 9 patients (9.8%), in 8 (88.9%) of whom they were eventually restored. Although paraplegia developed in 1 patient (1.1%) with a mycotic descending aneurysm, the other patients survived without spinal cord injury. CONCLUSIONS: Combined visualization of the Adamkiewicz artery and determination of motor-evoked potentials are useful in preventing spinal cord injury in descending and thoracoabdominal aortic repair.

Adult↗

PubMed1997

[Transesophageal echocardiography in cardiac anesthesiology].

Starting from 1995 in the 3rd Military Central Clinic Hospital by A. A. Vishnevskiĭ the staff specialists apply transesophageal echocardiography as intraoperative monitor when operating on heart. On their personal experience and literature information the authors prove that the method of intraoperative application of echocardiography in heart surgery is very effective. When operating on revascularization of myocardium, on correction or replacement of heart valve or foreign body removal, this method makes it possible to receive all necessary information on the functional and morphological changes in the heart right on the operation table. Transesophageal echocardiography proved itself as highly valuable for noninvasive evaluation of cardiovascular patients.

Anesthesia↗

PubMed2001

[Comparative survey of cardiac arrests during anesthesia and surgery in the 1980 s and 1999 s].

A survey of unexpected cardiac arrests, excluding those associated with cardiac surgery, that had occurred during anesthesia and surgery in the period 1980-1999 was conducted. There was no significant difference between the number of such cardiac arrests that occurred in the 1980 s (29/36,159, 0.080%) and the number in the 1990 s (33/37,643, 0.088%). According to the classification by Keenan et al., there were 3 cases (0.0083%) in the 80 s and 4 cases (0.0106%) in the 90 s that occurred due to anesthetic management. Cardiac arrests due to surgery itself significantly decreased from 21 cases in the 80 s to 6 cases in the 90 s, probably due to proper treatment for massive bleeding, a decrease in the number of cases of anaphylactic shock, and the development of novel anesthetics. Conversely, cardiac arrests due to preoperative conditions of the patients significantly increased from 5 cases in the 80 s to 23 cases in the 90 s. This increase seems to be due to an increase in the number of severe and multiple injuries and an increase in complicated major surgery. The increase in number of cases due to preoperative conditions also depends on coronary spasm and cardiac conduction insufficiency. Taking into consideration the improvement in intraoperative monitoring and the development of novel anesthetics in the 90 s, greater efforts should be made by anesthesiologists to reduce the incidence of cardiac arrest due to anesthetic management, and preoperative evaluation of surgical patients needs to be reconsidered.

Anesthesia↗

PubMed2006

A model of real time monitoring of the cochlear function during an induced local ischemia.

The aim of this study was to investigate the utility of distortion product otoacoustic emissions (DPOAEs) in intraoperative monitoring (IM) of cochlear ischemic episodes in animals during internal auditory artery (IAA) compression. The IAA was exposed using the posterior fossa approach and then compressed for 3 and 5 min intervals to effect ischemia. DPOAE amplitudes and phases were measured at 4, 8, and 12 kHz geometric mean frequency (GMF). In each monitored ear, laser-Doppler cochlear blood flow (CBF) was measured. All IAA compressions resulted in rapid decrease of DPOAE amplitude and CBF, with simultaneous DPOAE phase increase. DPOAE phase changes were found to increase consistently within several seconds of IAA compression, while corresponding DPOAE amplitudes changed more slowly, with up to 30-40 s delays. Following IAA release, DPOAEs at 12 kHz GMF were characterized by longer delays in returning to baseline than those measured at lower frequencies. In some cases, CBF did not return to baseline. In this animal model, DPOAEs were found to be sensitive measures of cochlear function during transient cochlear ischemic episodes, suggesting the utility of DPOAE monitoring of auditory function during surgery of cerebello-pontine angle tumors.

Animals↗

PubMed2000

Intraoperative SSEP detection of ulnar nerve compression or ischemia in an obese patient: a unique complication associated with a specialized spinal retraction system.

OBJECTIVE: To report a case of peripheral nerve compression caused by a specialized spinal retraction system, the Thompson-Farley retractor system, that most likely would not have been detected without intraoperative monitoring of the ulnar nerve. DESIGN: Bilateral median and peroneal nerve somatosensory evoked potentials (SSEPs) were monitored continuously during a C5 corpectomy, as was core body temperature. RESULTS: Within minutes after cervical soft-tissue retraction, the left ulnar nerve SSEP began to decline in amplitude. Peroneal nerve SSEPs were normal throughout the surgery; core body temperature remained at 36 degrees +/- 0.2 degrees C. After much effort to reposition the patient, the SSEPs returned to baseline and the Thompson-Farley system was replaced by a self-retracting system. CONCLUSIONS: To our knowledge, this is the first report of peripheral nerve compression caused by the Thompson-Farley retractor system. Even with careful positioning on the operating table, obese patients may be particularly at risk for upper arm compression. Continuous monitoring of SSEPs is suggested to prevent postoperative morbidity.

Diskectomy↗

PubMed2005

Anesthetic management of infants with palliated hypoplastic left heart syndrome undergoing laparoscopic nissen fundoplication.

The safety of laparoscopic surgery in infants with single ventricle physiology has been a subject of controversy despite potential benefits over open surgery. We present the anesthetic management of five infants with palliated hypoplastic left heart syndrome that underwent laparoscopic Nissen fundoplication. After anesthetic induction and tracheal intubation, an intraarterial catheter was placed for hemodynamic monitoring. Insufflation pressure was limited to 12 mm Hg and was well tolerated by all patients. There were no intraoperative or postoperative complications. In patients with hypoplastic left heart syndrome, laparoscopic Nissen fundoplication can be safely performed with careful patient selection and close intraoperative monitoring.

Anesthesia, General↗