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At least 145 records · Page 8Linked to original sources
PubMed1992

[Intraoperative monitoring auditory function during surgery of internal auditory canal and C-P angle].

Intraoperative measurement of electrocochleography, auditory brainstem responses and eighth nerve action potentials are utilized to assess the functional integrity of the cochlea and cochlear nerve. All such assessments have only one purpose: for warning the surgeon the possibility of damage the auditory system or its surrounding structure. Eighteen patients with various otoneurological diseases undergoing surgery had intraoperative monitoring of such evoked electrophysiological responses. Hearing was preserved in sixteen patients. However, the CM/N1 in ECochG still keep for a few minutes even after transection of the cochlear nerve and there is another disadvantage of need for signal averaging in BAER. Recording of the response of the the auditory nerve directly from the eighth nerve provides the surgeon with immediate information when an insult has been made to the cochlear and eighth nerve. Therefore, combination of these three measurements are recommended depending on the situation.

Audiometry, Evoked Response↗
PubMed1993

Transesophageal echocardiography as an intraoperative monitor.

Echocardiography is recognized as a excellent diagnostic tool for non-invasive cardiac assessment. Recently, transesophageal echocardiography has been utilized as an "on line, real time" intraoperative monitoring device in cases where patients are at significant risk for intraoperative cardiac ischemia, large shifts in hemodynamic parameters, and/or air embolism. This advancement in cardiac and hemodynamic intraoperative monitoring is significant as it enables early recognition of cardiac ischemia through assessment of cardiac contractility and regional wall motion abnormalities; accurate volume status assessment with direct monitoring of cardiac chamber volumes, valvular function, and intracardiac shunting; and real time assessment of the presence, size, and location of intracardiac air. Transesophageal echocardiography is a safe and accurate tool enabling early recognition of those physiological intraoperative changes where early intervention is critical for improved patient outcome.

Echocardiography, Transesophageal↗
PubMed1992

Intraoperative monitoring for thoracolumbar or lumbar surgery with somatosensory evoked potentials after double stimuli.

Somatosensory evoked potentials were after double stimuli on the posterior tibial nerve for the intraoperative monitoring in 58 thoracolumbar or lumbar surgeries. The first cortical positive potential P38 and P'38 after the second stimulus was recorded after double stimuli. Transient decreased amplitude more than 50% or missing potential of P'38 was found in 11 cases. These P'38 changes occurred in five procedures of retracting the nerve roots or dural sacs, three cases of reducing of thoracolumbar fractures, and two procedures of transpedicular screwing. No causative procedure was found in one case. In those 11 cases, 5 showed no abnormality in P38 potentials and 6 cases showed less decreased amplitude in P38 than in P'38. Consequently, P'38, which was evoked by the second stimulus, can be used for the intraoperative monitoring in the thoracolumbar and lower lumbar surgery.

Adolescent↗
PubMed1998

Transtracheal electrical stimulation of the spinal cord for intraoperative monitoring of the motor pathway.

Because of the suppressant effects of anesthetic drugs and muscle relaxants on motor responses elicited by either magnetic or electrical transcranial stimulation, intraoperative monitoring of the motor system, and especially monitoring of lower limb function, presents many difficulties. The upper part of the spinal cord was stimulated in 14 anesthetized and relaxed dogs with a cathode attached to the intratracheal tube and an anode fixed above the upper cervical spinous processes. Action potentials evoked by single and serial stimuli were recorded from the exposed right femoral nerve and quadriceps muscle Averaging was necessary for serial stimulations. Reproducible early and late responses to both single and serial stimulations were recorded during regular anesthesia. The origin of the different responses is discussed. Transtracheal stimulation of the spinal cord is easy to perform and the responses recorded from the peripheral nerve or limb muscle are well reproducible in regular anesthesia. The method seems to be appropriate for intraoperative monitoring of the thoracolumbar spine.

Action Potentials↗
PubMed1991

Eliminating diathermy-induced artifacts during intraoperative monitoring of somatosensory-evoked potentials: a hardware solution.

Somatosensory-evoked potentials (SEPs) recorded intraoperatively are often contaminated by artifacts arising from unipolar diathermy. This increases variability in serial SEP recordings and decreases the reliability of SEPs for intraoperative monitoring. Rejection of single sweeps on the basis of a voltage criterion can only partially prevent the inclusion of sweeps containing artifacts. We describe a low-cost hardware system that will halt SEP acquisition automatically before diathermy becomes active. Activation of the diathermy switch will halt SEP acquisition by sending a digital inhibit signal to the evoked potential machine via a fiberoptic cable. A timer delays the activation of the diathermy until the last sweep has been completed. To allow the electroencephalographic amplifiers to recover from any overload condition resulting from the high-voltage/high-frequency input during diathermy, acquisition is resumed only after a user-selectable time interval. The system was evaluated in 50 patients. It effectively interrupted SEP acquisition each time diathermy was used. By eliminating diathermy noise from the averaged waveforms, the system will allow evoked potential monitoring even during periods of intensive use of diathermy.

Artifacts↗
PubMed1991

Intraoperative monitoring of the facial nerve during decompressive surgery for hemifacial spasm.

In 11 consecutive patients, intraoperative electromyographic (EMG) recordings were made from the facial muscles during microvascular decompression for hemifacial spasm. In one patient, recordings could not be obtained for technical reasons, and two patients had no abnormality. In the remaining eight patients, the abnormal response resolved before decompression in two, resolved immediately at the time of decompression in five, and failed to resolve in one. All patients were relieved of their hemifacial spasm. In the five patients whose abnormalities resolved at the time of decompression, there was a precise intraoperative correlation between decompression of the nerve and disappearance of the abnormal EMG response. In three cases, this was a useful guide to the need to decompress more than one vessel. These results confirm the findings of Møller and Jannetta, support the use of this technique for intraoperative monitoring of facial nerve decompression procedures, and provide strong circumstantial evidence that vascular cross-compression is an important etiological factor in hemifacial spasm.

Electromyography↗
PubMed1981

The value of intraoperative monitoring using the pulse volume recorder during peripheral vascular reconstructive operations.

Despite precautionary measures, occasional intraoperative technical problems are encountered during vascular procedures. Early detection and correction at the time of initial operation afford the best opportunity for long term success of vascular reconstruction. From early 1978 to the middle of 1979, more than 400 vascular reconstructive procedures were monitored intraoperatively using the pulse volume recorder, a type of air plethysmography. In at least 15 instances, the pulse volume recorder was deemed instrumental in detecting an intraoperative technical misadventure. In all instances, the technical problem was corrected before the patient left the operating room. Intraoperative monitoring with the pulse volume recorder is a useful method to complement physical examination and angiography in the immediate evaluation of the results of arterial reconstructive procedures. Routine use could decrease technical complications and early graft failures in peripheral vascular reconstructive operations.

Aged↗
PubMed2004

Transcranial electrical stimulation through screw electrodes for intraoperative monitoring of motor evoked potentials. Technical note.

The feasibility of high-frequency transcranial electrical stimulation (TES) through screw electrodes placed in the skull was investigated for use in intraoperative monitoring of the motor pathways in patients who are in a state of general anesthesia during cerebral and spinal operations. Motor evoked potentials (MEPs) were elicited by TES with a train of five square-wave pulses (duration 400 microsec, intensity < or = 200 mA, frequency 500 Hz) delivered through metal screw electrodes placed in the outer table of the skull over the primary motor cortex in 42 patients. Myogenic MEPs to anodal stimulation were recorded from the abductor pollicis brevis (APB) and tibialis anterior (TA) muscles. The mean threshold stimulation intensity was 48 +/- 17 mA for the APB muscles, and 112 +/- 35 mA for the TA muscles. The electrodes were firmly fixed at the site and were not dislodged by surgical manipulation throughout the operation. No adverse reactions attributable to the TES were observed. Passing current through the screw electrodes stimulates the motor cortex more effectively than conventional methods of TES. The method is safe and inexpensive, and it is convenient for intraoperative monitoring of motor pathways.

Adolescent↗
PubMed1991

Guidelines for intraoperative monitoring of dental patients undergoing conscious sedation, deep sedation, and general anesthesia.

The promulgation and adoption of intraoperative monitoring standards in medicine for anesthesia has resulted in early detection of untoward events during sedation and anesthesia, lowering of malpractice premiums, and an improvement in the quality of care. The American Dental Society of Anesthesiology has devised specific, detailed monitoring standards with universal applicability in the dental setting.

Anesthesia, Dental↗
PubMed1996

Carotid endarterectomy. Lessons from intraoperative monitoring--a decade of experience.

OBJECTIVE: The authors analyzed a single institution's 10-year experience with intraoperative monitoring during 709 primary carotid endarterectomies and investigated the impact of contralateral internal carotid artery stenosis on carotid artery stump pressure (SP). SUMMARY BACKGROUND DATA: Stump pressure reflects the combination of contralateral carotid artery anatomy, collateral intracranial vasculature, and systemic blood pressure. By controlling for blood pressure with a stump index (SI) (SI = [SP/mean arterial pressure] x 100), a correlation between pressure and contralateral carotid artery anatomy can be demonstrated. Although the use of SP has long been advocated as an indicator of adequate cerebral perfusion, its correlation with perioperative complications while using an intraluminal shunt has not been evaluated completely. METHODS: From a series of 886 primary carotid endarterectomy cases, SP and mean arterial pressure were measured prospectively in 709 procedures. Temporary intraluminal shunts were used in cases with demonstrated contralateral carotid occlusion, prior cerebrovascular accident (CVA), or SPs less than 35 mmHg. Ipsilateral and contralateral angiographic degree of carotid stenosis was recorded at the time of the operation. Neurologic status was recorded prospectively for all 709 procedures. Operative electroencephalogram (EEG) changes and SP then were compared with the neurologic status of the patient in the perioperative period. RESULTS: The mean SP for the group (n = 709) was 46.7 +/- 15.3 mmHg (mean +/- standard deviation [SD]) with a mean SI of 54.9 +/- 22.6. The distribution for the SI is a more gaussian curve than that for SP. There were 19 ipsilateral CVAs (2.7%). The mean SP in the nonstroke group was 47.1 +/- 15.2 mmHg (mean SI = 54.7 +/- 16.5) compared with 31.9 +/- 13.2 mmHg (mean SI = 38.8 +/- 18.2) in the stroke group (P < 0.0001). Stroke rate for SP < or = 35 mmHg was 7% (13/185) versus 1.1% (6/524) for SP > 35 (p < 0.0001). Stump index and SP are related to contralateral carotid artery stenosis. The pattern of SI or SP versus contralateral stenosis is biphasic, with an increase at 75%. If SI is < or = 40, the mean contralateral stenosis is 55.1%; if SI is > 40, the mean contralateral stenosis is 35.1% (p < 0.05). Continuous EEG monitoring was completed for the 549 most recent operations. Patients who had a perioperative stroke had EEG changes observed during the procedure in only 6 of 12 cases (50% sensitivity), with 76% specificity. Using SP < or = 35 mmHg, sensitivity was 68% and specificity was 75%.

Aged↗
PubMed1994

Intraoperative monitoring of intact PTH during surgery for primary hyperparathyroidism.

The intraoperative differential diagnosis between adenoma and hyperplasia during surgery for primary hyperparathyroidism (pHPT) is sometimes difficult. Several methods have been proposed to aid the surgeon in deciding on the amount of parathyroid tissue to be resected. We examined the use of intraoperative monitoring of intact PTH in 47 patients operated upon for pHPT. The highly sensitive assay for intact PTH was modified to permit a total turn-around time from gland excision to obtained result of about 60 min. The correlation (r) between the results of the modified and the conventional method, which requires 24 h of incubation, was 0.98. At 15 min after removal of the parathyroid adenoma the levels of intact PTH had decreased by [mean (SD)] 85 (11)%. A decrease of 63% in intact PTH in patients with parathyroid adenoma predicted with 95% confidence the 4 patients with primary hyperplasia as not having parathyroid adenoma. We conclude that intraoperative measurement of intact PTH could be a valuable adjunct to surgical skill, especially for reoperative parathyroid surgery.

Adenoma↗
PubMed2004

[Neurophysiologic intraoperative monitoring to preserve cranial nerve function in base of skull surgery].

BACKGROUND: Neurophysiologic intraoperative monitoring (NIM) has gone through a renaissance since the advent of computer technology. Currently, both motor and sensory cranial nerves, including the IInd and VIIIth cranial nerves, can be intraoperatively controlled by means of small and mobile systems. PATIENTS AND METHODS: In order to estimate the value of NIM using the new generation of computer systems, we analyzed the records of 379 patients who underwent skull base surgery since 1996. These comprised NIM of the IInd, VIIth, VIIIth cranial nerves in most cases and of the IXth, Xth, XIth, and XIIth cranial nerves in selected cases. RESULTS: Whereas 72% of these cases demonstrated changes in the recorded intraoperative NIM signals, only 29% of them gave evidence of either clinical or electrophysiological neural function alterations during the postoperative follow-up. CONCLUSIONS: NIM is the only available system capable of providing the surgeon with instant intraoperative neural status-related feedback.

Computer Systems↗
PubMed2006

Intraoperative monitoring study of ipsilateral motor evoked potentials in scoliosis surgery.

Ipsilateral motor evoked potentials (MEPs) in spinal cord surgery intraoperative monitoring is not well studied. We show that ipsilateral MEPs have significantly larger amplitudes and were elicited with lower stimulation intensities than contralateral MEPs. The possible underlying mechanisms are discussed based on current knowledge of corticospinal pathways. Ipsilateral MEPs may provide additional information on the integrity of descending motor tracts during spinal surgery monitoring.

Adolescent↗
PubMedDate not supplied

[Temporary arterial occlusion and intraoperative monitoring of somatosensory evoked potentials during treatment of cerebral aneurysms].

Temporary occlusion of the main artery feeding aneurysm with intraoperative monitoring of somatosensitive evoked potentials was performed in 10 patients: in the majority of them because premature aneurysm rupture, and in 3 patients to facilitate the dissection of the aneurysm and application of a definitive clip. The duration of temporary occlusion was between 5 to 20 minutes. The basic changes of SEP abnormalities were manifested in the prolongation of absolute latencies and the central conduction time. The changes were reversible. One patient died 30 days after the operation from lung infection; the condition of one was unchanged; two patients with mental sequelae had good but long recovery; outcome in one patient was good and in the others it was excellent. Temporary occlusion may not have disastrous consequences, and it can be well tolerated if performed in a reasonable period of time. The SEP monitoring is helpful in the operative management of aneurysms showing early signs of ischaemia.

Aged↗
PubMed1998

[Surgical management for preserving motor function in patients with gliomas near the primary motor cortex: usefulness of preoperative identification of motor cortex and intraoperative monitoring of motor evoked potentials].

Preoperative identification of precentral gyrus and intraoperative monitoring of motor evoked potentials (MEPs) were performed to preserve postoperative motor function in seven patients with gliomas near the primary motor cortex. Tumors were astrocytomas in 3 patients, glioblastomas in 2 patients, anaplastic astrocytoma and mixed glioma in one patient each. Preoperative identification of the primary motor cortex was performed by three-dimensional (3D) display of magnetic resonance (MR) images and by functional images using MR imaging and single-photon emission tomography. The primary motor cortex identified by 3D display of MR images coincided well with that identified by functional images. 3D display of MR images was also useful for detecting the relationship between the tumor and the primary motor cortex. Intraoperatively, the central sulcus was confirmed by the finding of phase reversal of cortical somatosensory evoked potential, and this corresponded with the preoperative identifications by 3D display and by functional mapping. The primary motor cortex was stimulated electrically, and MEP (corticospinal evoked potential) was continuously monitored during surgery using electrodes inserted in the cervical epidural space. The amplitude of direct waves of MEPs during surgery was maintained above half of that recorded at the beginning of tumor removal, and all patients showed preservation of preoperative motor function. These results suggest that preoperative identification of precentral gyrus and intraoperative MEP monitoring provide useful information for preserving motor function in patients with gliomas near the primary motor cortex.

Adult↗
PubMed1994

Intraoperative monitoring of the vagus nerve during intracranial glossopharyngeal and upper vagal rhizotomy: technical note.

Intracranial section of the glossopharyngeal and upper vagal rootlets for the treatment of vagoglossopharyngeal neuralgia may cause dysphagia or vocal cord paralysis from injury to the motor vagal rootlets in 10% to 20% of cases. To minimize this complication, we recently applied a technique of intraoperative monitoring of the vagus nerve (previously described by Lipton and McCaffery to monitor the recurrent laryngeal nerve during thyroid surgery) in a patient undergoing intracranial rhizotomy for vagoglossopharyngeal neuralgia. By inserting an electrode in the ipsilateral false vocal cord and stimulating the rostral vagal rootlets intraoperatively under general anesthesia, we could differentiate the rostral vagal motor rootlets from the sensory rootlets. In this patient, the technique allowed us to preserve a rostral vagal rootlet, which if sectioned, could have caused dysphagia or vocal cord paralysis. We conclude that intraoperative monitoring of the rostral vagal rootlets is an important technique to minimize complications of upper vagal rhizotomy.

Adult↗
PubMed2002

[Use of propofol for carotid endarterectomy: its effect on parameters of intraoperative monitoring and clinical outcomes].

In order to evaluate the effects of propofol on neurologic outcomes of patients for carotid endarterectomy (CEA), intraoperative monitoring and postoperative complications were evaluated. Fifty two CEA cases were divided into two groups according to the method of anesthesia; group P (+) using propofol (n = 26), and group P (-) without propofol (n = 26). During cross-clamping of the internal carotid artery, oxygen saturation of internal jugular vein (SjO2) and somatosensory evoked potentials(SEP) were monitored continuously on the operated side. Moreover, the patients with postoperative neurological complications were examined for each parameter. There were no significant differences between the two groups in %SjO2, %SEP and number of cases with neurologic deficits. In the patients with poor outcomes, the value of stump pressure (SP) was significantly lower. We conclude that propofol had no significant effect against neurological complications in CEA patients, and SP monitoring was effective for evaluation of the clinical outcome in CEA patients.

Aged↗