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Results for “Monitoring, Intraoperative”

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At least 163 records · Page 9Linked to original sources

PubMed2002

[Intraoperative monitoring of hearing function in the removal of cerebellopontine angle tumor: auditory brainstem response and cochlear nerve compound action potential].

Intraoperative hearing monitoring may be the best approach for hearing preservation in the removal of cerebellopontine angle (CPA) tumors. We designed an intracranial electrode for a reliable and consistent recording of the cochlear nerve compound action potential (CNAP), and compared the efficiency of the CNAP and auditory brainstem response (ABR) while monitoring the CPA tumor removal. Simultaneous intraoperative monitoring of CNAP and ABR were performed in 7 patients with CPA tumors (5 acoustic neurinomas and 2 epidermoids) undergoing tumor removal aimed at hearing preservation. We designed an intracranial electrode for CNAP monitoring made of a fine malleable insulated wire with a tiny tuft of oxidized cellulose on the tip. Postoperatively, the hearing of 6 patients was preserved. Useful hearing was preserved in 5 of those. ABR recordings were unsatisfactory because of severe artifacts during the tumor removal. It was discernible only in 2 of the 7 patients. Postoperatively, useful hearing was preserved in the 2 patients with a discernible ABR during the tumor removal. Four of 5 patients with no discernible ABR during the tumor removal preserved hearing. Before the tumor removal, all patients showed a reproducible CNAP of an amplitude 20 times larger than the amplitude of ABR without artifacts. A reliable CNAP was recorded consistently throughout the tumor removal in 5 patients, in whom useful hearing was preserved postoperatively. CNAP disappeared completely during the tumor removal in 1 patient who lost hearing postoperatively. Because of severe artifacts and poor specificity, the intraoperative ABR monitoring can not predict the postoperative hearing condition. Our newly designed intracranial electrode enables consistent CNAP recording during tumor removal. CNAP reflects the effect of surgical manipulations on hearing and predicts the postoperative hearing condition. CNAP is a more efficient form of intraoperative monitoring than ABR during CPA tumor removal.

Action Potentials↗

PubMed2006

Revascularization and parent artery occlusion for giant internal carotid artery aneurysms in the intracavernous portion using intraoperative monitoring of cerebral hemodynamics.

OBJECTIVE: Therapeutic parent artery occlusion with or without revascularization is a useful surgical technique for the management of a giant aneurysm located in the intracavernous portion of the internal carotid artery (ICA). The purpose of the present study was to determine whether intraoperative cortical blood flow (CoBF) monitoring during surgical parent artery occlusion could identify patients who required bypass with a saphenous vein graft (high flow bypass). METHODS: Eleven patients with a giant aneurysm located in the intracavernous portion of the ICA underwent superficial temporal artery-middle cerebral artery bypass. CoBF was monitored intraoperatively in all patients using a thermal diffusion flow probe. The lowest CoBF during test occlusion of the ICA under functioning superficial temporal artery-middle cerebral artery bypass was determined, and the ratio of the value to the CoBF immediately before test occlusion of the ICA was calculated in the frontal and temporal lobes. When the CoBF ratio in the frontal or temporal lobe was less than 0.9, high flow bypass grafting was elected. RESULTS: Of the eleven patients undergoing superficial temporal artery-middle cerebral artery bypass, five patients underwent concomitant high flow bypass grafting. Postoperative cerebral ischemic events did not occur in any patient over a follow-up period ranging from 3 to 60 months. Postoperative cerebral angiography showed resolution of the aneurysm and patency of the bypass in all patients. CONCLUSION: Intraoperative CoBF monitoring using a thermal diffusion flow probe during surgical parent artery occlusion for giant intracavernous carotid artery aneurysms can identify patients who require concomitant high flow bypass grafting.

Aged↗

PubMed1996

Intraoperative monitoring of microvascular decompression in hemifacial spasm.

The significance of intraoperative electrophysiologic monitoring during microvascular decompression was evaluated prospectively in 261 patients with the hemifacial spasm from 1985 to 1995. The patients were divided into a monitored group and a non-monitored group. Identification of the offending vessels was facilitated by the monitoring during the surgical procedure and the complication rate of the monitored group was significantly lower than that of the non-monitored group (p < 0.05). In addition, the abnormal muscle response continued to improve during the follow-up period, thus the electrophysiological status of the hemifacial spasm after the microvascular decompression improved significantly with time (p < 0.05). In conclusion, intraoperative monitoring is useful for identifying the exact offender among multiple vessels, and lowering the complication rate of the microvascular decompression for the hemifacial spasm.

Adult↗

PubMed2003

[Specifics of preoperative care, intraoperative monitoring and postoperative evaluation of patients with thyroid carcinoma].

The aim of the study was to show the standards of preoperative management, intraoperative monitoring and postoperative evaluation of patients with thyroid gland carcinoma. It was point out the importance of the preoperative diagnosis of the tumor, and the concurrent diseases. The special attention was paid to difficult airway recognition and resolving this situation. Both, anesthetist's and surgeon's point of view of perioperative and postoperative complications were discussed with special interest on early surgical complications and the need for urgent anesthetic treatment. Criteria for minimal and desirable monitoring of vital functions were suggested in order to prevent, recognize and cure complications. Our conclusions were based on recent references from the world literature and on our own experience in Center for endocrine surgery KCS, Belgrade.

Anesthesia↗

PubMed1996

Intraoperative monitoring with pulse Doppler ultrasonography in transsphenoidal surgery: technique application.

We describe an intraoperative use of pulse Doppler ultrasonography in transsphenoidal surgery to prevent mechanical vascular injury, particularly to the intracavernous portion of the internal carotid artery. This system is integrated by connection to a video processor. The use of Doppler sonography provided real-time measurement of arterial or venous flow velocity and source of flow by both real-time sonograms and sound frequencies. With the use of a microprobe, 1 mm in diameter, vessels located within 7 mm from the tip of the probe could be easily, rapidly, and noninvasively detected, without disturbing operative field. Furthermore, both the size and the distance of a vessel could be measured by turning the dial of Doppler signal gain from initially waxing to waning Doppler sounds, because the acoustic sounds were adjusted to the axial flow of each vessel in 0.1-mm increments. Our intraoperative monitoring enhanced operative safety with technical simplicity and reliability.

Adenoma↗

PubMed1993

[Intraoperative monitoring of the facial nerve in transtemporal surgery of acoustic neurinoma].

Acoustic neuroma ablation by the enlarged middle cranial fossa approach results in a low incidence of postoperative facial nerve dysfunction. In 25 consecutive patients with tumors in the cerebellopontine angle with a diameter up to 2.3 cm, intraoperative monitoring of the facial nerve was evaluated. The facial nerve was monitored electrophysiologically with recordings of the spontaneous EMG and electrically evoked potentials (CMAP) from at least three groups of facial muscles. In 4 cases monitoring was helpful for identification and delineation of the facial nerve. The mechanically elicited potentials during tumor preparation and CMAP after electrical stimulation close to the brain stem were compared with the postoperative facial nerve function and the time course of recovery. If the ongoing EMG recordings resulted in potentials below 0.5 mV and the CMAP at the end of tumor preparation was higher than 0.5 mV, facial nerve function was normal in 9 of 10 cases on the first postoperative day. One patient had mild facial palsy. Poor results could be predicted if numerous discharges with amplitudes higher than 0.5 mV and affected CMAP after stimulation near the brain stem were found at the end of surgery. All 3 patients with these findings had facial paralysis at hospital discharge (an average of 9 days after the operation). Recovery from the palsies was found to be prolonged. Intraoperative monitoring of the facial nerve is now used routinely in surgery of the cerebellopontine angle and the internal auditory canal.

Adult↗

PubMed2000

Intraoperative monitoring to preserve central visual fields during occipital corticectomy for epilepsy.

Photic driving using a flashing strobe light was recorded via intracranial electrodes in two patients with occipital epilepsy being evaluated for surgery. The same technique was used to monitor the visual cortex intraoperatively. Visual evoked potentials (VEPs) were also obtained using the intracranial electrodes in one patient. Preoperative photic driving occurred in a separate location from the cortical areas producing ictal epileptiform activity. VEPs were located in the same site as photic driving. Photic driving was monitored throughout the resection and remained unaffected at the end of each procedure. Postoperative visual field testing in both patients showed preservation of central vision although some reduction in peripheral fields was seen. Intraoperative monitoring of the visual cortex using photic stimulation proved to be a reliable technique for preserving central vision during occipital lobe surgery.

Adult↗

PubMed1995

Efficacy of intraoperative neurophysiological monitoring.

Intraoperative neurophysiological monitoring is of benefit in protecting tissue at risk for trauma or ischemia during surgical procedures. Monitoring modalities include EEG, computer processed EEG, somatosensory (SEP), auditory (BAEP), and visual evoked potentials (VEP), and cranial nerve monitoring. The efficacy of monitoring is controversial, because no properly controlled prospective study of outcome with and without monitoring has been done. The weight of evidence suggests that loss of spontaneous EEG and SEP correlate well with critical reductions of cerebral blood flow. Meta-analysis of series comprising 3,028 patients undergoing carotid endarterectomies shows that SEP deteriorated in 5.6% of cases, with 20% of these having postoperative deficits, but more might have had deficits if they had not been shunted. SEP monitoring can be useful in surgery affecting brain and cord vasculature. Monitoring is not indicated for routine lumbosacral spine surgery. BAEPs have predictive value for preservation of hearing after acoustic neuroma surgery, and other surgery near the brainstem. VEPs have been too variable to be of major use in the operating room. For neurophysiologic monitoring to be useful, it must be performed by an experienced team, and the surgeon must be willing to act on the findings. Under these circumstances, monitoring can reduce surgical complications in selected cases.

Brain↗

PubMed2002

Near infrared spectroscopy for intraoperative monitoring of the spinal cord.

STUDY DESIGN: Animal model study of three healthy commercial pigs was conducted. OBJECTIVE: To determine whether near infrared spectroscopic monitoring of the spinal cord is feasible, and whether changes in near infrared spectroscopy correlate with changes in blood flow to the cord or operative maneuvers. SUMMARY OF BACKGROUND DATA: Near infrared spectroscopy is a noninvasive continuous monitoring tool capable of measuring absolute changes in the concentration of three chromophores: oxygenated hemoglobin, deoxygenated hemoglobin, and cytochrome aa3, the terminal enzyme in the electron transfer chain and a measure of cellular energy equilibrium. Near infrared spectroscopy has been used to monitor the brain intraoperatively in multiple circumstances. The authors hypothesized that near infrared spectroscopy could be used to monitor the spinal cord's cellular energy equilibrium during spinal surgery (i.e., that vascular compromise could be identified before irreversible damage occurred). METHODS: The posterior elements of the spine were exposed, and near infrared spectroscopy optodes (fiberoptic bundles) were sutured to either the lamina or the spinous processes of T9, T10, or both and directed toward the spinal cord. Interventions included manipulation of oxygen saturation and distraction of the T9-T10 disc space. RESULTS: With reduced oxygen delivery (lower arterial oxygen saturation and blood flow), oxygenated hemoglobin concentration decreased and deoxygenated hemoglobin concentration increased. With distraction, blood volume (oxygenated hemoglobin plus deoxygenated hemoglobin) decreased, and cytochrome aa3 became more oxidized. Changes were apparent within 1 second of the intervention beginning, and recovery to the baseline of near infrared spectroscopy occurred with relief of each intervention. CONCLUSIONS: This near infrared spectroscopy technique monitors changes in oxygenation of the spinal cord, and therefore appears capable of intraoperative warning about impending vascular compromise of the spinal cord.

Animals↗

PubMed1992

Intraoperative monitoring by transtympanic electrocochleography and brainstem electrical response audiometry in acoustic neuroma surgery.

The preservation of hearing is a major aim of contemporary temporal bone surgery. Our present findings demonstrate that intraoperative monitoring is a key method for attaining serviceable postoperative hearing after the removal of an acoustic neuroma. Both electrocochleography (ECoG) and brainstem electrical response audiometry were performed in 96 patients operated on for acoustic neuromas. The specificity of the different monitoring methods was affected by surgical manipulations in addition to such non-specific influences as CSF drainage, core body temperature and anesthesia. In the present study ECoG was found to be more reliable in assessing the intra- and postoperative course with respect to the preservation of cochlear function.

Audiometry, Evoked Response↗

PubMed1994

[Intraoperative monitoring in patients undergoing surgery of lesions involving the cavernous sinus].

We reviewed the intraoperative monitoring and anesthesia in 45 patients, who had undergone operation of lesions involving the cavernous sinus between September, 1990, and May, 1993. The patient was placed in a 30 degree of head-up position to reduce the bleeding from the cavernous venous plexus. However, air embolism during the operation has not been noted in any patients. In 13 of 45 patients, a transient or permanent internal carotid artery (ICA) occlusion was performed intraoperatively under the brain protection by thiopental and the monitoring of electroencephalograph, somatosensory evoked potentials, local cerebral blood flow, and oxygen saturation of internal jugular vein. There has been no complications related to the ICA occlusion. In 7 patients, intraoperative recordings of evoked extraocular muscle activities were undertaken to monitor ocular motor nerve function. Responses from the inferior rectus muscle to the oculomotor nerve stimulation, and from the lateral rectus muscle to the abducens nerve stimulation, were obtained in 5 patients and 1 patient, respectively. Intraoperative neurophysiological monitoring in the surgery of lesions involving the cavernous sinus is crucial to reduce the surgical complications, and a team approach, including neurosurgeons, anesthesiologists, and medical engineers, is important for the future progress.

Adolescent↗

PubMed2001

[Swelling of the tongue after intraoperative monitoring by transesophageal echocardiography].

Tongue swelling after surgery is a rare but potentially lethal postoperative complication. This is a case report of a 62-yr-old patient who developed tongue swelling after intraoperative monitoring by transesophageal echocardiography. The patient underwent replacement of the descending aorta with an interposition graft under cardiopulmonary bypass. A transesophageal echocardiography (TEE) probe was inserted after the induction of general anesthesia. Surgery and anesthesia were uneventful. After the surgical procedure, the TEE probe was removed. At that time, marked swelling of the tongue was noted. However, there was no diffuse edema in the neck, face, supraglottic structures or the larynx. The tongue swelling was thought to have been caused by local mechanical compression of the tongue with the TEE probe. The tongue returned to normal size the next day. Care should be taken to prevent the occurrence of this complication during and after TEE examination under general anesthesia.

Echocardiography, Transesophageal↗

PubMed1993

Up and down the spinal cord: intraoperative monitoring of sensory and motor spinal cord pathways.

Monitoring of spinal cord function during certain orthopedic and neurosurgical procedures is done to reduce the likelihood of neurologic complications. This article is based on intraoperative experiences gained at Duke University Medical Center since 1978. Both ascending sensory (up) and descending motor (down) data can be evaluated to assist in improved patient outcomes. Refinements in technique and better understanding of the neural generators of evoked potentials obligate the components to have improved sensitivity and specificity of spinal intraoperative monitoring. An additional improvement has been the intraoperative use of motor evoked potentials. This discussion deals with a description of specific responses obtained following lower-limb mixed nerve stimulation in terms of neural generation, influences of rate and intensity, and anesthetic effects. The techniques and advantages of bipolar epidural recording and stimulation are discussed. Motor tract stimulation via the same epidural electrodes used for recording of sensory components is described. Case reports are presented to emphasize major points.

Adolescent↗

PubMed1989

Neurophysiologic intraoperative monitoring: II. Facial nerve function.

Intraoperative facial nerve monitoring provides a potentially useful adjunct to recent surgical advances in neurotology and neurosurgery. These measures further aid the surgeon in preserving facial nerve function by enhancing visual identification with electrical monitoring of mechanically evoked facial muscle activation. Facial nerve monitoring in neurotologic surgery may achieve the following goals: (1) early recognition of surgical trauma to the facial nerve, with immediate feedback made available to the surgeon through monitoring of mechanical activation; (2) assistance in distinguishing the facial nerve from regional cranial nerves and from adjacent soft tissue and tumor with selective electrical stimulation; (3) facilitation of tumor excision by electrical mapping of portions of tumor that are remote from the facial nerve; (4) confirmation of nerve stimulability at the completion of surgery; and (5) identification of the site and degree of neural dysfunction in patients undergoing nerve exploration for suspected facial nerve neoplasm or undergoing decompression in acute facial palsy. This paper provides an overview of intraoperative facial nerve monitoring principles and methodology and reports a recent clinical investigation that demonstrates the utility of facial nerve monitoring in translabyrinthine acoustic neuroma surgery.

Electric Stimulation↗

PubMed1996

[Carotid TEA in asymptomatic stenoses--is intraoperative monitoring a conditio sine qua non?].

Continuous registration of somatosensory evoked potentials and continuous electroencephalographic monitoring (computerized topographic brain mapping) during carotid endarterectomy are the most used methods to predict the need for shunt insertion. Between 1990 and 1994 a consecutive series of 78 carotid endarterectomies for asymptomatic stenoses without any cerebral monitoring was performed in our department. In all patients an indwelling shunt had been inserted. The perioperative neurological morbidity and mortality rate was 0. In our opinion there is no need for an intraoperative monitoring during carotid endarterectomy if certain principles referring to the operative technique will be noted.

Aged↗

PubMed2001

Intraoperative monitoring in neuroanesthesia: a national comparison between two surveys in Germany in 1991 and 1997. Scientific Neuroanesthesia Research Group of the German Society of Anesthesia and Intensive Care Medicine.

UNLABELLED: Two surveys initiated by the Neuroanesthesia Research Group of the German Society of Anesthesia and Intensive Care Medicine examined the practice of intraoperative monitoring during intracranial procedures in Germany in 1991 and 1997. Questionnaires were mailed to departments that were registered members of the German Society of Anesthesia and Intensive Care Medicine and that provided neuroanesthesia service on a routine basis in 1991. In 1997, the survey was repeated in the 1991 respondents. In 1991, 68 departments and in 1997, 44 departments returned completed questionnaires, indicating a response rate of 87% for 1991 and of 65% for 1997. Compared with 1991, the standards for monitoring, such as surveillance of oxygenation, ventilation, circulation, and body temperature, were universally applied in adult and pediatric patients in 1997. Overall, there was a 20% increase in neuromuscular blockade monitoring and in the use of electroencephalography and evoked potentials in 1997 compared with 1991. Further brain-specific monitoring was rarely provided in 1997. Overall, jugular venous oximetry was used in 20% and transcranial Doppler ultrasonography in 15% of responding hospitals. To detect venous air embolism in sitting patients, 75% of all responding hospitals used precordial Doppler ultrasonography in both years, whereas transesophageal echocardiography was more often used in 1997 (38%) as compared with 1991 (17%). IMPLICATIONS: Standards of anesthetic monitoring were surveyed in neuroanesthesia in Germany in 1991 and 1997. Central nervous system monitoring was not the standard of practice.

Adult↗

PubMed1990

Intraoperative monitoring of regional wall motion abnormalities for detecting myocardial ischemia by transesophageal echocardiography.

Transesophageal two-dimensional echocardiography has been used for intraoperative monitoring of regional wall motion of the left ventricle. Regional wall motion abnormality is a sensitive indicator of myocardial ischemia and the use of two-dimensional transesophageal echocardiography may have a substantial advantage for early detection of myocardial infarction and thus for initiating timely and appropriate therapy in preventing postoperative myocardial ischemia. With an expected increase in the use of intraoperative transesophageal echocardiography for monitoring regional wall motion, we described the practical aspects of transesophageal echocardiography: (1) insertion technique of transesophageal echocardiographic probe; (2) the technique for obtaining an optimal short-axis view of the left ventricle; and (3) the method for evaluating regional wall-motion abnormality and myocardial ischemia. Regional wall motion abnormality is best monitored at the mid-papillary muscle level where all three coronary arteries meet. In obtaining this view, the transesophageal echocardiographic probe was found to be predominantly located in the stomach. Failure in obtaining short-axis view of the left ventricle at this level occurred in patients with left ventricular dilatation or obesity. Because of the anatomical reason, the echocardiographic transducer cannot reach a proper plane. In anesthetized patients, air can be pushed into the stomach during induction and may disturb the visualization. The pitfalls in examining regional wall motion abnormalities include: (1) shifting of the center of left ventricular contraction; (2) inadequate direction of the scanning plane; and (3) paradoxical septal movement. Three cases are presented to demonstrate the usefulness of transesophageal echocardiography in managing coronary artery surgical patients.

Aged↗

PubMed1988

Neurophysiologic intraoperative monitoring: I. Auditory function.

As a result of advances in neuro-otology and neurosurgery, surgeons often operate in the vicinity of sensitive and delicate neural structures in an attempt to restore their function, remove tumor, or alleviate distressing and disabling symptoms. Concerns about preservation of neural function during these surgical procedures have provided the need and motivation for the development and adaptation of neurophysiologic techniques designed to provide feedback about impending trauma. The most common functions that are at risk in neuro-otologic surgery are related to the auditory nerve and centers and the facial nerve. This paper deals with principles and practices of intraoperative monitoring of auditory function. The following applications are illustrated and discussed: 1) intraoperative monitoring of auditory function during posterior fossa tumor resection, 2) auditory brain stem response and VIIIth nerve monitoring during retrolabyrinthine vestibular nerve section, 3) monitoring of auditory function during microvascular decompression of cranial nerve VII, VIII, or IX, and 4) special applications related to cochlear implant surgery.

Brain Stem↗