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Results for “Monitoring, Intraoperative”

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At least 451 records · Page 25Linked to original sources

PubMed2000

Accurate localization of an insulinoma by preoperative selective intra-arterial calcium injection and intraoperative glucose monitoring.

The role of pre- and intraoperative procedures for the localization of insulinomas has been extensively debated. We report a case of successful treatment using preoperative selective intra-arterial calcium injection and intraoperative glucose monitoring. A 12-year-old boy with hypoglycemic attacks had a large insulinoma in the head of the pancreas on computed tomography. Preoperative selective angiography combined with arterial stimulation-venous sampling (ASVS) by intra-arterial injection of calcium revealed no other insulinomas in the body and tail of the pancreas. Elevation of serum glucose on intraoperative monitoring confirmed complete enucleation of the insulinoma. Preoperative ASVS can accurately localize an insulinoma, and may help to increase the success rate of surgery and avoid blind pancreatectomy.

Blood Glucose↗

PubMed2002

Impact of brain shift on intraoperative neurophysiological monitoring with cortical strip electrodes.

BACKGROUND: Intraoperative neurophysiological monitoring has become the standard procedure for locating eloquent regions of the brain. Such continuous electrical stimulation of motor pathways is usually applied by means of flat silicon-embedded electrodes placed directly on the motor cortex. However, shifting of the silicon strip on the cortical surface as well as electrode displacement due to brain shift underneath the electrode can lead to inaccurate recordings not directly caused by intraoperative impairment of the motor cortex or the motor pathways. METHOD: This prospective study was conducted to quantify cortical brain shift during open cranial surgery and to assess its impact on electrode positioning in 31 procedures near the precentral gyrus. Three groups of different lesion volumes were distinguished. Movement of the cortex between opening of the dura and completion of tumor removal as well as cortical electrode shifting were digitally measured and analyzed. FINDINGS: Cortical surface structures evidenced a significantly larger shift (up to 23.4 mm) in comparison to the electrode strips (up to 4.2 mm) in lesions with a volume of over 20 ml. Cortex shifting highly correlated with lesion volume, whereas strip electrode movement was almost unidirectional and did not differ significantly among the three groups. However, the way they were placed (completely on the cortex vs. partly underlying or overlapping the craniotomy borders) affected the magnitude of their intraoperative displacement. As a consequence, 3 of the 31 cases (9.3%) showed a significant change in the recorded motor responses due to intraoperative dislocation of the stimulating electrode. INTERPRETATION: Changes in the location of cerebral structures due to intraoperative brain shift may exert a marked influence on intraoperative neurophysiological monitoring if cortical strip electrodes are used. Therefore, long-term monitoring of the central region requires continuous checking of the position of stimulating electrodes and, if necessary, correction of their location.

Adult↗

PubMed2001

[The role of transesophageal echocardiography in intraoperative hemodynamic monitoring].

Transesophageal echocardiography (TEE) is a semi-invasive diagnostic tool which allows a unique intraoperative visualization of cardiac chambers and valves. It is mainly used for intraoperative monitoring during cardiac surgery and in cardiopathic patients undergoing major non cardiac surgical procedures. TEE gives a beat-to-beat assessment of cardiac morphology and function, it is less invasive and more readily performed than pulmonary artery catheterization, and it allows an etiological diagnosis of hemodynamic problems. Based on TEE data, the anesthesiologist is able to modify in real time vasoactive therapy and fluid management. TEE data concern: 1) preload: left ventricular endodiastolic area is measured and this is considered an index of volemia; 2) systolic function: the circumferential shortening fraction, which correlates with LV ejection fraction, is measured; 3) onset of ischemia: ischemia is detected as a regional modification of normal kinetics; 4) causes of hemodynamic instability; 5) assessment of sovrahepatic anastomoses during liver transplantation.

Blood Volume↗

PubMed2005

Esophageal Doppler (ODM II) improves intraoperative hemodynamic monitoring during laparoscopic surgery.

Minimally invasive laparoscopic surgery has been expanded to the elderly and high-risk surgical patients with underlying cardiac and pulmonary disease. However, possible cardiovascular changes during CO2 pneumoperitoneum necessitate close intraoperative monitoring. In this prospective study, 55 patients (mean age 62.52 years, range 26-82) undergoing laparoscopic surgery were included. Patients were categorized into 3 groups of low (group A: 12 patients, mean age 55.5 years), moderate (group B: 22 patients, mean age 59.5 years), and high (group C: 21 patients, mean age 69.71 years) surgical risk according to ASA physical status classification. Similar anesthetic agents and anesthetic techniques were used in the above cases. An esophageal Doppler (ODM II, Abbott Laboratories) was used to measure aortic blood flow velocity and thereby estimating stroke volume (SVe) and cardiac output (COe) throughout anesthesia, in addition to traditional monitoring. After abdominal insufflation (peak intra-abdominal pressure: 13-15 mm Hg) COe values decreased from the initial value after induction of anesthesia by 22%, 20%, and 18% for groups A, B, and C, respectively (P < 0.05). The above values further deteriorated (25%, 28%, and 30% for groups A, B, and C, respectively) in the anti-Trendelenburg positioning of the patient. The peak aortic blood flow velocity (PV) followed the changes, thus indicating that heart muscle contractility is affected during the procedure. Stabilization of the above values was achieved after 20 minutes of CO(2) pneumoperitoneum and improvement was noted only after deflation of the abdomen. Heart rate and blood pressure essentially remained unchanged throughout the procedure, although the final values were increased compared with initial. Insufflation of the abdomen with CO(2) produces measurable effects on the cardiovascular system that require reappraisal of hemodynamic monitoring during anesthesia. ODM II offers a reliable, relatively noninvasive, cost-effective tool for intraoperative monitoring of the hemodynamic changes with a potential for future application for improvement of intraoperative hemodynamic status of patients.

Adult↗

PubMed1993

Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.

Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. The spinal cord was stimulated using either epidural or subarachnoid electrodes. Compound muscle action potentials were recorded from quadriceps and tibialis anterior muscles. Well-formed, stable motor-evoked potentials were recorded in all but one patient, in whom a preexisting myelopathy was felt to preclude recording. Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.

Action Potentials↗

PubMedDate not supplied

[Intraoperative facial nerve monitoring: results].

Intraoperative facial nerve monitoring is performed by electromyographic recording of motor action potentials generated by facial nerve stimulation or mechanical damage of the facial nerve, and helps the surgeon to localize the course of this nerve, reduce the possibility of its injury during surgery, and assure its anatomical and functional integrity. We report our experience on the intraoperative facial nerve monitoring in 35 patients, ten of which belong to absolute indications for monitoring, and to relative indications the remaining cases. In every case, we used the Nerve Integrity Monitor (NIM-2), manufactured by Xomed. Assessment of facial nerve integrity degree is performed pre- and postoperatively using the House-Brackmann classification. We only found in two cases (5.7%) some degree of palsy in the late postoperative period. No correlation was found between the recorded intraoperative response and the functional results in the early postoperative period.

Adolescent↗

PubMed1994

Intraoperative SEP monitoring in neurosurgery around the brain stem and cervical spinal cord: differential recording of subcortical components.

The results of intraoperative monitoring of median nerve somatosensory evoked potentials (SEP's) were evaluated in 75 neurosurgical patients in order to assess the role of differential derivation of brain stem (P14) and spinal cord (N13) wave activity. These components were compared with the conventionally recorded neck potential ("N13") that reflects overlap of P14 and N13. The spinal cord N13 wave was recorded from the posterior to anterior lower aspect of the neck and the brain stem P14 wave from the midfrontal scalp to the nasopharynx; both derivations enabled isolated low-artifact recording of these components. In 18.7% of patients, moderate to major latency and/or amplitude shifts of N13 or P14 were found that were masked in conventional neck-scalp recordings of "N13". There was a 6.7% false-negative rate in this series. Using a neck-scalp derivation alone, a 14.7% false-negative rate would have resulted and an isolated worsening of the P14 component (with stable neck potential) in six cases would have been overlooked. It is concluded that the proposed SEP recording technique allows independent assessment of spinal cord and brain stem activity. It is, therefore, superior to the conventional neck-scalp derivation technique, in which important information may be concealed or even lost due to the overlap of the brain stem P14 and spinal cord N13 potentials.

Adolescent↗

PubMed2001

Angled rigid neuroendoscope for continuous intraoperative visual monitoring: technical note.

We developed and tested a new, angled rigid endoscope as a tool for performing continuous visual monitoring during microsurgery. The shaft of the scope is angled 110 degrees at its midportion using a prism. We used the scope continuously in 30 cases including 15 pituitary tumours, 7 brain tumours, 7 cerebral aneurysms, and one hemifacial spasm. For pituitary tumours the tip of the scope was positioned in the sphenoid sinus or in the cavity formed by tumour removal; for cerebral aneurysms it was placed behind the parent artery or the aneurysmal neck. Image quality was acceptable for intraoperative monitoring. In no case did the neuroendoscope have a deleterious impact on th e proper function of the microscope or surgical instruments. This angled rigid scope was more effective for intraoperative monitoring than conventional straight scopes.

Endoscopes↗

PubMed1997

Evaluation with evoked and spontaneous electromyography during lumbar instrumentation: a prospective study.

The neuroanatomical structures that approximate the bony pedicles of the lumbar spine allow little room for technical error or compromise of the bone during pedicle screw insertion. Currently available neurophysiological monitoring techniques detect compromised bone and nerve root injury after it occurs. The purpose of this prospective study is to evaluate the reliability and efficacy of a unique neurophysiological monitoring technique. This technique provides immediate evaluation of pedicle cortical bone integrity in patients undergoing lumbar fusion with instrumentation by using electrified surgical instruments throughout the pedicle screw fusion procedure. Spontaneous electromyographic (EMG) activity was also monitored. Intraoperative evoked EMG stimulation was performed using a pedicle probe and feeler as monopolar stimulators during the insertion of 164 pedicle bone screws in 32 patients. The EMG response to subthreshold stimulation intensities indicated cortical bone compromise. Immediate and conclusive feedback via evoked EMG activity using stimulating pedicle probes in appropriate muscle groups was successful in identifying pedicle cortical bone compromise in four patients. One false-negative evoked EMG study was noted but was identified via spontaneous EMG activity. Intraoperative EMG monitoring alerted the surgeon that redirection of the pedicle probe or screw was necessary to avoid nerve root irritation or injury and served as an early warning system. Evoked EMG stimulation proved to be reliable and efficacious, especially when used in combination with spontaneous EMG. This technique may provide an added safeguard during implant placement procedures at centers where intraoperative neurophysiological monitoring is routinely performed.

Adult↗

PubMed2001

Hemifacial spasm: intraoperative electromyographic monitoring as a guide for microvascular decompression.

OBJECTIVE: Microvascular decompression is the logical and well-accepted treatment of choice for hemifacial spasm (HFS). In experienced hands, good to excellent results can be obtained. However, sometimes the exact site of the vascular compression is unclear. The aim of this study was to analyze whether intraoperative monitoring by stimulated electromyography of the facial nerve may help to improve the results of vascular decompression for HFS. METHODS: In a series of 74 patients operated for HFS, the impact of intraoperative facial nerve monitoring on the surgical procedure was analyzed by use of the clinical and operative patient records. The role of this type of monitoring, with assessment of the so-called abnormal muscle response, was broken down into four categories: a guiding, a confirming, an indirect confirming, or an inconclusive role. The relationship between abnormal muscle response monitoring results and final surgical outcome was analyzed. RESULTS: The overall cure rate was 87.8%, including patients who had previously undergone unsuccessful operations. Complications were minor, and hearing impairment was found in 2.7% of patients. A guiding role of intraoperative monitoring was apparent in 33.8% of patients, and a confirming role was demonstrated in 52.7% of patients, which resulted in a positive contribution of approximately 87% for intraoperative facial monitoring in microvascular decompression for HFS. In patients defined as guiding cases, the cure rate was 92%. CONCLUSION: This study demonstrates the applicability and usefulness of intraoperative facial nerve monitoring in microvascular decompression operations for HFS.

Adult↗

PubMed2001

Prospective analysis of the efficacy of continuous intraoperative nerve monitoring during thyroidectomy, parathyroidectomy, and parotidectomy.

OBJECTIVE: Continuous intraoperative electromyographic monitoring was prospectively performed in all parotidectomies, thyroidectomies, and parathyroidectomies over approximately 5 years to assess the efficacy of this technology. STUDY DESIGN AND SETTING: Continuous intraoperative nerve monitoring with perioperative nerve assessment was performed. The postresection minimal stimulation level of the nerves was determined to evaluate if this level would predict nerve function postoperatively. RESULTS: Forty-four parotidectomies and 70 thyroid/parathyroid operations were performed with 140 nerves at risk (44 facial, 96 recurrent laryngeal). The incidence of temporary facial paralysis was 15.9% (7 of 44) and the incidence of permanent paralysis was 0%. The incidence of temporary recurrent laryngeal nerve paralysis in terms of nerves at risk was 1.0% (1 of 96), and the incidence of permanent recurrent laryngeal nerve paralysis was 0%. All patients with normally functioning facial and recurrent laryngeal nerves postoperatively had minimal stimulation levels less than or equal to 0.4 mA. CONCLUSION: Continuous intraoperative nerve monitoring was associated with extremely low rates of temporary and permanent nerve paralysis in our series of 140 nerves at risk as compared to the rates documented in the literature.

Adolescent↗

PubMed1984

Continuous intraoperative EEG monitoring during carotid surgery.

Continuous intraoperative EEG monitoring and stump pressure measurements were studied during 85 carotid revascularizations performed in 40 symptomatic cerebrovascular patients and in 32 asymptomatic subjects with a cervical bruit. The decision to place a temporary shunt was made on the basis of intraoperative EEG abnormalities regardless of stump pressure values. 11 patients with contralateral carotid lesions showed marked EEG alterations, at the moment of clamping, which returned to normal after the placement of an indwelling shunt. Stump pressure values showed a wide variation and a poor correlation with intraoperative EEG changes. In the early postoperative period there were no deaths; no new neurological deficits were detected. In the follow-up there was only 1 asymptomatic carotid rethrombosis, not revealed by the EEG, which was suspected by Doppler sonography and confirmed by angiography. The authors conclude that EEG gives valuable information about cerebral functions during carotid revascularization and can reduce the intraoperative complications of the procedure. Stump pressure measurement cannot be used alone as a safe indicator of cerebral ischemia during carotid cross-clamping.

Aged↗

PubMed2005

Microvascular decompression for primary hemifacial spasm. Importance of intraoperative neurophysiological monitoring.

There is considerable evidence that primary Hemi-Facial Spasm (HFS) is in almost all cases related to a vascular compression of the facial nerve at its Root Exit Zone (REZ) from brainstem, and that Micro-Vascular Decompression (MVD) constitutes its curative treatment. Clinical as well as electrophysiological features plead for mechanisms of the disease in structural lesions at the neural fibers (putatively: focal demyelination at origin of ephapses) and functional changes in the nuclear cells (hyperactivity of the facial nucleus). Lateral Spread Responses (LSRs) elicited by stimulation of the facial nerve branches testify of these electrophysiological perturbations. Monitoring LSRs during surgery is feasible; however the practical value of their intraoperative disappearance as control-test of an effective decompression remains controversial.MVD allows cure of the disease in most cases. Because the VIIIth nerve is at risk during surgery, intraoperative monitoring of Brainstem Auditory Evoked Potentials (BEAPs) is of value to reduce occurrence of hearing loss. Increase in latency of Peak V and decrease in amplitude of Peak I are warning-signals of an excessive stretching of the the cochlear nerve and impairment of the cochlear vascular supply, respectively.

Cochlear Nerve↗

PubMedDate not supplied

[Multimodal intraoperative electrophysiological monitoring during cerebellopontine angle tumor surgery. Benefit or loss?].

In the Neurosurgery Department, Silesian University School of Medicine, continuous monitoring of selected neurophysiological functions of the central and peripheral nervous system was introduced in 1998 as a routine procedure in cerebellopontine angle surgery and some other operations performed in the petroclival region. Such benefits from this method as increased patient safety, availability of information about dynamic changes in the monitored structures, and the possibility of cranial nerves localization using stimulation in the operating area, are quite obvious. The paper presents results of a detailed statistical analysis of the amount of time required for preparation and for operating in 174 cerebellopontine angle tumor surgeries performed in the years 1986-2002 with (group M) and without (group BM, before the year 1998) intraoperative monitoring. Subgroups distinguished according to the histological type of tumor were evaluated. Out of 95 procedures performed in group M, 57 were operations of acoustic neurinoma cases, 15 meningiomas, 8 cases of epidermal cyst, and 15 other growth processes in the cerebellopontine angle region. Among 79 operations in group BM, there were 57 cases of acoustic neurinoma, 4 cases of meningioma, 8 cases of epidermal cyst, and 10 of other types of neoplastic growth. In group M as compared to group BM the pre-op. preparation time was found to be significantly longer in cases of the VIII-th nerve neurinoma, and of other tumors. No statistically significant differences in the amount of operating time in were found between any of the subgroups. Both radicality of tumor removal and facial nerve status have clearly improved since intraoperative monitoring was introduced.

Adolescent↗

PubMed2004

Spinal cord monitoring using intraoperative somatosensory evoked potentials for spinal trauma.

BACKGROUND: Intraoperative spinal cord monitoring is commonplace in scoliosis surgery as an adjunct to evaluate functional integrity of the cord; however, limited information is available on its applicability in spinal trauma. METHODS: We investigated the efficacy of somatosensory evoked potential (SEP) recording during reconstructive procedures in 82 patients who sustained 20 cervical, 8 thoracic, 6 thoracolumbar, and 48 lumbar vertebral fractures or fractures-dislo-cations. Seventy-one patients underwent single anterior or posterior operations and 11 combined anterior-posterior procedures. Forty patients had incomplete injuries, and 42 had no preoperative neurologic deficit. SEP trace amplitude at insertion of electrode was considered as the baseline value and was compared with the lowest intraoperative signal amplitude and the amplitude at completion of operation. RESULTS: Fifty-nine patients had a depression in wave amplitude of >25% during surgery; in 25 patients, the trace fell by >50%, and in 7 cases, a >75% diminution was recorded. A loss of 50% in SEP signal amplitude showed 67% sensitivity and 71% specificity in predicting neurologic outcome. Increasing trace deterioration threshold from 50% to 60% improved specificity to 81% without compromising sensitivity. A loss of >50% in SEP amplitude occurred with significantly increased incidence during the anterior compared with the posterior spinal procedures. More than 20% recovery in signal amplitude at the conclusion of the procedure in patients with incomplete injuries was correlated with favorable neurologic function. CONCLUSION: Persistent intraoperative decrement in SEP amplitude and poor restitution at completion of surgery increase the risk for postoperative neurologic compromise.

Adolescent↗

PubMed2001

[Quick intraoperative parathormone monitoring].

Successful parathyroidectomy for primary hyperparathyroidism has traditionally consisted of bilateral neck exploration with identification of all parathyroid glands and excision of grossly abnormal glands. Recently it has been reported that preoperative localization combined with intraoperative monitoring of parathyroid hormone enables performing directed unilateral cervical explorations while maintaining similar cure rates. This new surgical approach, feasible under local anesthesia as an outpatient procedure, decreases operative time, improves cosmetic results and may reduce morbidity. We report preliminary results of our experience in implementing this method.

Adult↗

PubMed2002

Targeted parathyroidectomy in the era of intraoperative parathormone monitoring.

A combination of preoperative localization and intraoperative parathormone (PTH) monitoring permits targeted parathyroidectomy. Multiple approaches have been developed, ranging from unilateral neck exploration (UE) to radio-guided parathyroidectomy (RP) to endoscopic parathyroidectomy (EP). The purpose of this study was to evaluate the efficacy of these approaches in the management of primary hyperparathyroidism. From June 1998 to November 2000 a total of 110 targeted parathyroid operations were performed at a university medical center. All patients underwent technetium-99m-sestamibi scanning, ultrasonography, or both prior to surgery. Intraoperative PTH monitoring was utilized in all cases. Thirty-seven patients underwent UE, 59 underwent RP, and 14 underwent EP. Follow-up ranged from 1 to 24 months. All patients were cured following parathyroidectomy as predicted by a more than 50% reduction of the intraoperative PTH level following removal of all hypersecreting glands. Altogether, 103 patients had a solitary adenoma (95%), and 1 patient had a parathyroid carcinoma. Six patients (5%) had multigland disease, including four cases of hyperplasia and two patients with a double adenoma. Eighty-three patients (75%) were discharged the day of surgery. The use of preoperative localization and intraoperative PTH monitoring permits a targeted approach to the treatment of primary hyperparathyroidism. Endocrine surgeons should be facile in all minimally invasive parathyroid techniques to individualize the operative approach.

Adult↗

PubMed1981

Activated clotting time monitoring of intraoperative heparinization: our experience and comparison of two techniques.

The activated clotting time (ACT) has been used clinically for 41/2 years to monitor the adequacy of intraoperative heparinization in both cardiopulmonary bypass (CPBP) and peripheral vascular surgery (PVS) patients. Since January, 1976, we have operated on 440 PVS patients in our institutions, of whom 255 had intraoperative monitoring of heparinization by means of the ACT test; an additional 185 patients received heparin according to an empiric protocol. An automated machine for determining the ACT (Hemochron) had been used on the last 28 patients in the ACT group. We conclude that: (1) the ACT is an acurate method of monitoring anticoagulation during PVS, (2) the Hemochron is a simple and effective machine to perform the ACT, (3) values obtained by the Hemochron generally exceed those of the ACT done by hand by approximately 20 seconds at lower levels of heparin and are equal at higher levels of heparin, (4) supplemental heparin was required in 22% of our patients to maintain their ACT values at twice control values, (5) the response to heparin is twofold: an initial sensitivity or resistance followed by an independent and variable rate of consumption, and (6) the ACT is a useful method for predicting inadequate heparin reversal or heparin rebound at the conclusion of the operation.

Autoanalysis↗