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At least 433 records · Page 24Linked to original sources
PubMed1994

Intraoperative SEP monitoring in aneurysm surgery.

Somatosensory evoked potentials (SEP) were monitored during surgical treatment of 282 aneurysms in 226 patients. Significant SEP changes were found in 32 aneurysms (11.3%) mainly referring to accidental or intentional vessel occlusion. Response to these changes included reapplication of aneurysm clips, repositioning of retractors, or removal of temporary clips as followed in 23 cases (8.1%). Stable SEP signals allowed the surgeon to proceed with the surgical course and coincided in all but 2 cases (0.7%) with an uneventful outcome. Despite the limitations of SEP monitoring in certain anatomical locations, it has been found to be helpful in the operative management of some cases such as multilobed aneurysms, giant aneurysms, trapping procedures, and procedures requiring temporary vessel occlusion.

Adolescent↗
PubMedDate not supplied

A simplified procedure for continuous intraoperative external monitoring of systemic leakage during isolated limb perfusion.

AIMS: Isolated limb perfusion (ILP) with high doses of an alkylating agent alone or in combination with tumor necrosis factor (TNF) in hyperthermic conditions (HAP) has been proposed for the treatment of locoregional tumors. A critical step in ILP/HAP is accurate monitoring of systemic leakage to prevent the toxic effects of chemotherapy, and in particular of TNF. Ten percent systemic leakage from the perfusion circuit is considered the maximum acceptable leakage. In this study we report our experience of a new leakage monitoring system. MATERIALS AND METHODS: Ths new simplified procedure is based on the use of 99mTc-labeled soluble human serum albumin (HSA) and a hand-held gamma probe as detector. The procedure consists of the following steps: 1) A standardized 99mTc-HSA dose of 0.5 MBq/kg body weight is injected into the perfusion circuit before chemotherapy/TNF perfusion and a hand-held gamma probe (IGP) is placed over the precordial area in a zone that was marked on the skin during a simulation test; 2) 48-72 hours before ILP/HAP a complete simulation test is performed with a 99mTc-HSA dose corresponding to 10% of the total dose calculated for the patient's body weight; 3) during the simulation test the maximum count-rate zone on the precordial area is detected by IGP and marked on the patient's skin; 4) a 60-min curve of effective 99mTc-HSA radioactivity decay (physical and biological) is calculated and fitted; 5) to compare external counting with the effective circulating radioactivity, patient blood samples and circuit blood samples are taken every five minutes during ILP/HAP and measured by a laboratory gamma counter and very convenient thanks to the favorable characteristics of IGP. The placed in the operating room. RESULTS: External counting with a hand-held gamma probe was easy to perform time/activity curves obtained during simulation tests showed a regular and constant effective decay with a mean decay rate of 30% at 60 minutes compared to baseline values. The external measurements obtained by IGP proved to be well correlated with blood samples measured in vitro by a laboratory gamma counter. The results of this procedure, in particular the data of the simulation test for each patient, allowed us to correct the limit of 10% maximum leakage during ILP/HAP in accordance with the time/activity curve. CONCLUSIONS: Although 99mTc-HSA has some unfavorable characteristics, it offers many advantages over 131I-HSA. The procedure proposed by us, which was based on the use of an IGP and 99mTc-HAS at a standardized dose of 0.5 MBq/kg body weight and on an individual simulation test for each patient performed 48 hours before ILP/HAP, proved to be simple and accurate in monitoring systemic leakage during ILP/HAP anti-cancer therapy.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1997

[Intraoperative EEG monitoring using a neural network].

OBJECTIVE: To introduce a new EEG parameter for monitoring a patient's cerebral status during anaesthesia. METHOD: EEG epochs (channel C3 P3, duration 30 see per epoch) yield patterns used as the training input of a self-organising neural network (neural gas algorithm). Each pattern contains spectral components. An additional "suppression parameter" reflects the proportion of flat curves during an EEG epoch and reduces the shortcomings of spectral analysis. The enhanced pattern vector enables the recognition of burst-suppression periods representing depressed cerebral activity during anaesthesia. Following training with 25549 EEG epochs ¿recorded in 196 consenting patients in the period beginning 5 minutes before induction of anaesthesia to extubation¿ the network knows 125 basic patterns (neural clusters). The neural clusters are responsible for different stages of anaesthesia: some neurons are activated by EEG epochs of awake patients, others are stimulated by deep stages. The homogeneity of the EEG epochs of cluster is checked. The portion of the EEG epochs not recognised by the network (7.5%) contains heterogeneous and sporadic patterns (mainly outlines caused by artefacts). RESULTS: In comparison with commonly used variables of anaesthesiological EEG monitoring (spectral edge or median frequency) neural discriminant analysis achieves better discrimination between awake and deeply anaesthetised stages (reclassification of 96% vs. 70%). On the basis of 56 complete sequences of patterns (from the beginning of the infusion of anaesthetics to the occurrence of burst suppression) a trend value of between 0.0 and 100.0 is assigned to each neural cluster. In contrast to existing methods, induction of anaesthesia causes a strictly linear increase in the electroencephalographic trend. CONCLUSIONS: Detailed neural cluster and discriminant analysis on the basis of the model described leads to an improved EEG parameter which better reflects the hypnotic effects of anaesthetic agents and arousal reactions caused by pain stimuli. Misclassifications of awake and anaesthetised stages are reduced. The neural network learns to recognize the complex changes in EEG patterns during induction of anaesthesia with different agents.

Adult↗
PubMed1998

Two-staged resection of a left frontal astrocytoma involving the operculum and insula using intraoperative neurophysiological monitoring--case report.

A 29-year-old right-handed male with a 12-year education presented with a 2-month history of generalized epileptic activity. Neuroradiological imaging demonstrated a large lesion in the left frontal lobe involving the insulooperculum and in the temporal tip. Neurological and neuropsychological examination revealed no abnormality. Two-staged total resection of a left frontal large astrocytoma involving the insulooperculum was achieved, with preservation of the speech and motor functions. The prefrontal area was resected en bloc under general anesthesia. To avoid vascular damage including the lenticulostriate arteries, the sylvian and the interhemispheric fissures were thoroughly opened. The tumor was apparently located in the anatomical Broca's area. Eighteen days later, the residual tumor was totally resected with no language deficit after identifying the motor-speech cortex, which was displaced from the usual location, by direct cortical stimulation under local anesthesia. The medially extended insular tumor was then resected stepwise with frequent neurological monitoring with the patient awake. Surgery for intraaxial insuloopercular lesions in the dominant hemisphere carries a high risk of speech and motor deficit. This staged operation enables maximum tumor resection of dominant-side large frontal gliomas involving the insuloopercular region, with preservation of both motor and speech functions.

Adult↗
PubMed1999

[Intraoperative indirect monitoring of electrocardiogram].

The electrocardiogram (ECG) is used as a standard monitoring method during anesthesia and operation. But during the operation of severely burnt patients, the electrodes for ECG cannot be placed on the ideal points for the standard limb leads. We tried the indirect monitoring of the ECG. We placed the electrodes on the sheet over the operating table, and connected the patient and the electrodes with water. By this way the ECG similar to the standard limb leads could be recorded. This method is useful for the patients, with such diseases as severe burn, severe atopic dermatitis and epidermolysis bullosa hereditaria.

Electrocardiography↗
PubMedDate not supplied

Intraoperative thermographic monitoring during neurogenic thoracic outlet decompressive surgery.

This article reports the use of thermography to monitor 123 plexus decompressions for neurogenic thoracic outlet syndrome. The diagnosis and management of this disease continues to be controversial. Questions about pathologic mechanisms, the extent and frequency of muscular entrapment, scar, and interdigitations, as well as their relative contributions, remain. Thermographic visualization of the operated extremity allowed us to map and correlate thermal changes with specific surgical manipulations, as well as to analyze the tissues resected to better answer these questions. Initial thermal abnormalities indicating, usually, ulnar entrapments or irritation, normalized sequentially as discrete entrapments were resected. Thermographic monitoring continues to provide surgically useful information in one third of operations.

Adult↗
PubMed2003

[Criteria of functional operability and indications for intraoperative volumetric monitoring of patients during extensive surgical procedures on the lung].

The investigation included 32 patients after extensive operative interventions on the lungs: pneumonectomy with circular resection of the trachea bifurcation and different kinds of combined pneumonectomies. Methods of Doppler echocardiography and thermal dilution were used for studying the parameters of lesser circulation before, during and after operation. Patients with the initially impaired hemodynamics had more pronounced functional changes after surgical procedures. The shift limits of the main ultrasonic indices of the right ventricle function were determined in order to form a group of the higher prognostic risk.

Adult↗
PubMed1992

[Intraoperative microbiological monitoring in abdominal aortic aneurysms in elective surgery. A review of the literature and the authors' personal experience].

Thirty-one patients, ranging in age from 57 to 78 years (mean 66), with the exclusion of cases with doubtful possible results, underwent abdominal aortic aneurysmectomy for asymptomatic AAA and had cultures from the aneurysmal wall and endovascular thrombus to identify possible microbiological source of future graft infection; 5 (16%) of 31 cultures yielded bacterial growth and the most common organism isolated was staphylococcus epidermidis. During an average follow-up of 15.4 months no graft infection was noted in patients with positive or negative aortic cultured. A literature review stresses the same disparity between positive cultures obtained at the aneurysmectomy and subsequent low graft-infection rate. It is concluded that the aneurysm wall itself does not represent an important source of early or late graft infection and it's suggested that the bacterial presence both in the wall and thrombus could be explained by an exogenous contamination at the operation time.

Aged↗
PubMed1993

[Localization of central sulcus by means of cortical SEP recordings: clinical feasibility and usefulness of intraoperative electrophysiological monitoring].

Clinical feasibility and usefulness of various intraoperative electrophysiological monitoring methods that are widely utilized during neurosurgical operations were critically evaluated. We divided these intraoperative monitoring methods (IOM) into two types; the monitoring methods that enable the surgeons to obtain topographical orientation during operative procedures ('topographical IOM') and those that give them knowledge of the functional state of the nervous system that is involved in the operative procedures ('functional IOM'). It was shown why 'topographical IOM' is reliable and useful, based on our experiences of cortical SEP recordings to localize the central sulcus, and why the present 'functional IOM' is less reliable to guide the surgeons precisely during the operations. We presented some technical methods to cope with these problems in 'functional IOM'. It is necessary to establish a good correlation between the intraoperative changes of the evoked potentials and the pathological changes responsible for these electrical changes as established in clinical electrocardiography.

Adult↗
PubMed1996

Intraoperative electrophysiologic monitoring of the recurrent laryngeal nerve.

Intraoperative electrophysiologic monitoring of the recurrent laryngeal nerve was performed with a commercially available device consisting of an endotracheal tube with integrated stainless-steel-wire surface EMG electrodes positioned at the level of the true vocal cords. Forty-two recurrent laryngeal nerves were successfully monitored with this system in 31 patients undergoing thyroidectomy or parathyroidectomy. In all cases, evoked EMG responses were elicited by direct electrical recurrent laryngeal nerve stimulation. Stimulus thresholds for evoked responses ranged from 0.2 to 0.6 mA (mean 0.3 mA) for the 37 nerves with preoperative ipsilateral normal vocal cord mobility. Mechanically evoked potentials with acoustic signals were also detected during the surgical procedures related to recurrent laryngeal nerve manipulation. It may be concluded that surface electrode monitoring of the recurrent laryngeal nerve with this system provides a simplified, noninvasive technique that is as sensitive as monitoring with intramuscular laryngeal electrodes.

Adolescent↗
PubMed2007

Intraoperative neurophysiological monitoring technology: recent advances and evolving uses.

Intraoperative neurophysiological monitoring has evolved over the last 25 years to become an important component of many types of orthopedic and neurosurgical procedures. From its foundations in VIII cranial nerve surgeries and scoliosis corrections surgeries, intraoperative neurophysiological monitoring has expanded to incorporate nearly all spine procedures and many involving the brain and brainstem. Fundamental to this growth in the use of intraoperative neurophysiological monitoring has been the development of the technology used to perform the neurophysiological tests. Advancements in electronics and computer technology have resulted in significant improvements in the capacity, ease of use, quality and reliability of the equipment as well as the quality of and control over the acquired data. These technological advancements have resulted in remarkable improvements in not only the quality and availability of intraoperative neurophysiological monitoring, but also, as a consequence, patient care, and have arguably propelled the expansion of the use that intraoperative neurophysiological monitoring has seen over the last 10 years.

Biomedical Technology↗