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PubMed2004

Intraoperative monitoring of the corticospinal motor evoked potential (D-wave): clinical index for postoperative motor function and functional recovery.

The corticospinal motor evoked potential was investigated as a monitoring index of motor function to perform maximal resection of brain tumors located around the motor cortex in 37 patients with glioma. Tumor resections were performed under general anesthesia with muscle relaxant and completely controlled ventilation. No special arrangements for anesthesia were required. Direct cortical stimulation revealed that if one electrode was placed on the posterior half of the precentral gyrus, the D-wave could be recorded even when using an electrode separation of 10 mm, and the amplitude was larger with anodic rather than cathodic stimulation. Monitoring of the D-wave enabled the function of the corticospinal tract to be evaluated selectively. Postoperative persistent motor disturbance remained in six patients who had a decrease of over 30% in amplitude of the D-wave during tumor resection. A decrease of less than 30% may indicate postoperative preservation of motor function, including transient motor disturbance with subsequent complete recovery. Intraoperative monitoring of the D-wave is suitable for open cranial surgery with general anesthesia, can detect the primary motor cortex, and allow maximal resection of brain tumors located around the motor cortex.

Brain Neoplasms↗

PubMed2004

Intraoperative monitoring for tethered cord surgery: an update.

OBJECT: Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. METHODS: Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. CONCLUSIONS: Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.

Anal Canal↗

PubMed2000

Intraoperative monitoring of the inferior alveolar nerve during mandibular sagittal-split osteotomy.

In order to evaluate the risk of nerve injury and to prevent iatrogenic damage at different stages of bilateral sagittal-split osteotomy (BSSO) of the mandible, we monitored the function of the inferior alveolar nerve (IAN) continuously on both sides in 13 orthognathic patients undergoing BSSO. The IAN was stimulated at the mental foramen with two monopolar needle electrodes fixed to the dental splint, and the orthodromic sensory nerve action potentials (SNAP) of the IAN were recorded with a silver-wire electrode inserted near the oval foramen on each side. The latencies, amplitudes, and sensory nerve conduction velocities at baseline, after medial opening, sawing, splitting, eventual manipulation, and fixation of the mandible were analyzed. The monitoring method functioned technically well in 25 of 26 nerves. Both the surgical technique and the duration of medial opening had conspicuous effects on the function of the IAN, which led us to modify the medial approach. When finer instruments were used for retraction and the duration of medial opening was shortened to less than 10 min, the SNAP of the IAN was always preserved at this stage. Monitoring of the IAN also prevented nerve injury during splitting and fixation. This technique for intraoperative monitoring of the IAN seems to be a feasible and promising tool for objective evaluation of intraoperative events and for prevention of nerve injury during BSSO.

Adolescent↗

PubMed2002

The impact of neurophysiological intraoperative monitoring on surgical decisions: a critical analysis of 423 cases.

OBJECT: The aim of this observational clinical study was to analyze the impact of neurophysiological intraoperative monitoring (IOM) on the surgical procedure and to assess the benefits of such monitoring. METHODS: Data for 423 patients who underwent neurophysiological IOM with somatosensory evoked potentials and brainstem auditory evoked potentials during neurosurgical procedures were collected prospectively. The patients were classified into one of five groups according to the findings of IOM, the intervention following a monitoring alarm, and the patient's postoperative neurological condition. These groups were as follows: patients with true-positive findings with intervention (42 cases, 9.9%), those with true-positive findings without intervention (42 cases, 9.9%), those with false-positive findings (nine cases, 2.1%), those with false-negative findings (16 cases, 3.8%), and those with true-negative findings (314 cases, 74.2%). Different interventions followed an event identified with monitoring. These interventions were related to dissection in 17 cases, to perfusion pressure in 11, to a limitation of the surgical procedure in five, to vessel clipping in four, to vasospasm in three, and to retraction in one case. In one case the surgical procedure was abandoned. A critical analysis and cautious estimation of the interventions revealed that IOM was helpful in preventing a postoperative deficit in 5.2% of the monitored cases. CONCLUSIONS; For critical analysis of the benefits of IOM one must evaluate not only the findings of IOM and the patient's postoperative neurological condition but also the intraoperative findings and surgical interventions following a monitoring alarm. Evidence is presented that IOM is helpful in preventing a postoperative deficit.

Adolescent↗

PubMed1997

Intraoperative monitoring of the motor pathway using transtracheal stimulation of the cervical spine in dogs.

Although SEP monitoring of the spinal cord has been a well established method recently, not an ultimate, perfectly developed technique for monitoring of the motor system is known so far, particularly, because of the disturbing effect of narcotic drugs and relaxants on the motor evoked potentials. In this study 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 to the cervical spinous processes. Single and serial stimuli were applied. Recordings were obtained from the exposed right femoral nerve and quadriceps muscle. Averaging was necessary when using serial stimulations. Responses were consequent and reproducible during regular anesthesia. The origin of the different responses in the spinal cord is discussed. The method seems to be appropriate for intraoperative monitoring of the thoracolumbar spine.

Anesthesia, General↗

PubMed1998

"Threshold-level" multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring.

UNLABELLED: Numerous methods have been pursued to evaluate function in central motor pathways during surgery in the anesthetized patient. At this time, no standard has emerged, possibly because each of the methods described to date requires some degree of compromise and/or lacks sensitivity. OBJECT: The goal of this study was to develop and evaluate a protocol for intraoperative monitoring of spinal motor conduction that: 1) is safe; 2) is sensitive and specific to motor pathways; 3) provides immediate feedback; 4) is compatible with anesthesia requirements; 5) allows monitoring of spontaneous and/or nerve root stimulus-evoked electromyography; 6) requires little or no involvement of the surgical team; and 7) requires limited equipment beyond that routinely used for somatosensory evoked potential (SSEP) monitoring. Using a multipulse electrical stimulator designed for transcranial applications, the authors have developed a protocol that they term "threshold-level" multipulse transcranial electrical stimulation (TES). METHODS: Patients considered at high risk for postoperative deficit were studied. After anesthesia had been induced and the patient positioned, but prior to incision, "baseline" measures of SSEPs were obtained as well as the minimum (that is, threshold-level) TES voltage needed to evoke a motor response from each of the muscles being monitored. A brief, high-frequency pulse train (three pulses; 2-msec interpulse interval) was used for TES in all cases. Data (latency and amplitude for SSEP; threshold voltage for TES) were collected at different times throughout the surgical procedure. Postoperative neurological status, as judged by evaluation of sensory and motor status, was compared with intraoperative SSEP and TES findings for determination of the sensitivity and specificity of each electrophysiological monitoring technique. Of the 34 patients enrolled, 32 demonstrated TES-evoked responses in muscles innervated at levels caudal to the lesion when examined after anesthesia induction and positioning but prior to incision (that is, baseline). In contrast, baseline SSEPs could be resolved in only 25 of the 34 patients. During surgery, significant changes in SSEP waveforms were noted in 12 of these 25 patients, and 10 patients demonstrated changes in TES thresholds. Fifteen patients experienced varying degrees and durations of postoperative neurological deficit. Intraoperative changes in TES thresholds accurately predicted each instance of postoperative motor weakness without error, but failed to predict four instances of postoperative sensory deficit. Intraoperative SSEP monitoring was not 100% accurate in predicting postoperative sensory status and failed to predict five instances of postoperative motor deficit. As a result of intraoperative TES findings, the surgical plan was altered or otherwise influenced in six patients (roughly 15% of the sample population), possibly limiting the extent of postoperative motor deficit experienced by these patients. CONCLUSIONS: This novel method for intraoperative monitoring of spinal motor conduction appears to meet all of the goals outlined above. Although the risk of postoperative motor deficit is relatively low for the majority of spine surgeries (for example, a simple disc), high-risk procedures, such as tumor resection, correction of vascular abnormalities, and correction of major deformities, should benefit from the virtually immediate and accurate knowledge of spinal motor conduction provided by this new monitoring approach.

Adolescent↗

PubMed2002

A laboratory evaluation of an auditory display designed to enhance intraoperative monitoring.

UNLABELLED: Encouraged by the popularity of the pulse oximeter pulse-tone, we developed and tested an auditory display of six physiologic variables. The display consisted of a cardiovascular sound triggered by every heartbeat (conveying heart rate) and a respiratory sound triggered by every breath (conveying respiratory rate). Attributes of the cardiovascular sound were modulated to convey hemoglobin saturation and blood pressure, and those of the respiratory sound were modulated to denote end-tidal CO(2) and tidal volume. Three display formats (auditory, visual, and combined) were compared. Fourteen anesthesia residents monitored dynamic displays of 6 variables to detect and identify 6 predefined events during 21 trials. An event occurred during each trial and the subject's task was to detect when it started and then identify the type of event. Subjects detected every event. They detected events more rapidly with the combined display (10.4 s) than with the visual (12.8 s) or auditory (13.0 s) displays. Subjects correctly identified events least often with the auditory display (60% versus visual 88% and combined 80%). They correctly identified events more quickly with the combined display than with the visual display. We conclude that, with little training, clinicians can successfully detect and identify simulated clinical events using an auditory display of six variables. IMPLICATIONS: We developed and tested an auditory display of multivariable clinical data. With little training, clinicians successfully used the display to detect and diagnose simulated critical events. This suggests that a multivariable auditory display could enhance intraoperative monitoring.

Adult↗

PubMed1997

Intraoperative monitoring of skin temperature changes of hands before, during, and after endoscopic thoracic sympathectomy: using infrared thermograph and thermometer for measurement.

OBJECTIVE: To investigate the roles of the second and third thoracic spinal segments in the preganglionic sympathetic innervation of the hand, and to compare skin temperature changes between thenar and other parts of palm before, during, and after endoscopic thoracic sympathectomy. DESIGN: Twelve patients, four women and eight men, with severe palmar hyperhydrosis underwent endoscopic thoracic sympathectomy. The T3 segment was identified and dissected first, followed by T2 segment extirpation. Skin temperature changes of the hand were assessed by thermograph and thermometer simultaneously before, during, and after sympathectomy. Sympathetic skin responses were undertaken 1 day preoperatively and followed up 6 months postoperatively. SETTING: An electrophysiological laboratory and operating room in a national medical center. SUBJECTS: Twelve patients who sustained a profound degree of palmar hyperhydrosis. INTERVENTIONS: Skin temperature differences of the hands were measured by infrared thermograph and thermometer before, during, and after endoscopic thoracic sympathectomy. MAIN OUTCOME MEASURES: Group's average temperature differences, and sympathetic skin response (all or none response). RESULTS: The T2 spinal segment is thought to be the main source of sympathetic outflow to the sweat glands of the hand. The group's average temperature changes were significantly higher at the 2nd through 5th fingers' tips than at the thenar after completion of T2 extirpation (p < .005). CONCLUSIONS: Intraoperative monitoring of palmar skin temperature, as judiciously measured by infrared thermograph, yields useful information about the locations of the sympathetic segments and confirmation of their entire ablation by endoscopic thoracic sympathectomy.

Adolescent↗

PubMed1997

Intraoperative monitoring of jugular bulb oxygen saturation in patients with moyamoya disease.

The jugular bulb oxygen saturation (SjO2) and end-tidal carbon dioxide (ETCO2) were monitored continuously during surgery in six cases of Moyamoya disease who had demonstrated multiple episodes of transient ischemic attacks (TIAs) and/or fluctuating neurological deficits preoperatively. The arterial carbon dioxide tension (PaCO2) levels were also measured repeatedly at predetermined interval. In two cases (group H), the ETCO2 was controlled at hypercapnic levels during surgery (45.5 +/- 1.5 mmHg) and the remaining four (group N) were operated on in a normocapnic state (39.0 +/- 2.0 mmHg). The group H patients demonstrated high levels of SjO2 ranging from 72 to 85%, indicative of excessive hyperemia. One of the group H patients demonstrated mild and transient motor weakness postoperatively. The group N patients demonstrated normal levels of SjO2 ranging from 66 to 78%. All the patients in both groups demonstrated fluctuations in SjO2 levels in clear positive correlation with spontaneous changes in PaCO2 levels. The present findings indicated that: (1) Global carbon dioxide reactivity of cerebral perfusion is well preserved in patients with Moyamoya disease; and (2) hypercapnia in these patients often causes excessive hyperemia. The occurrence of postoperative neurological deficits in association with such an excessive hyperemia suggests that hyperapnia during surgery is not always beneficial. Intraoperative monitoring of SjO2 is useful for maintaining cerebral perfusion within the optimum range.

Adolescent↗

PubMed2002

Intraoperative monitoring of parathyroid hormone with a rapid automated assay that is commercially available.

The Mayo Clinic was one of the first institutions to develop an in-house rapid parathyroid hormone (PTH) assay that used homegrown antibodies to monitor plasma PTH levels during parathyroidectomy. This PTH assay is economical, but it requires highly trained technologists and an experienced laboratory director and it is difficult to perform in the operating suite. We sought a fully automated multipurpose autoanalyzer with bar code reader to identify different patients' names and capacity to manage specimens from several patients who are having simultaneous operations. In addition, after complete tumor removal, the plasma PTH level should decrease to < 25% of the baseline level; otherwise, it may indicate that the antibodies used in the assay have cross-reacted with long half-life fragments other than intact PTH, which has a half-life of only approximately 2 min. An automated multipurpose analyzer, the Immulite 1000 with a Turbo PTH kit (DPC), fits these criteria and has replaced our in-house rapid assay. Of 47 patients who had parathyroidectomy for primary hyperparathyroidism and were tested with the new equipment, 45 (96%) had their plasma PTH levels decrease to < 25% of the baseline levels. In 41 of 47 patients (87%), the PTH value decreased to < 5 pmol/L (provisional reference range) within 20 min after tumor excision. The usefulness of the PTH assay extends from the traditional diagnosis of parathyroid disease to intraoperative monitoring, helping to ensure a higher cure rate.

Automation↗

PubMed2006

[Real-time intraoperative monitoring of recurrent laryngeal nerve in thyroid surgery under general anesthesia].

OBJECTIVE: To evaluate the clinical significance and application value of the real-time intraoperative monitoring (RTIM) technique in preventing recurrent laryngeal nerve (RLN) from injury during operation. METHODS: The RTIM of RLNs by nerve integrity monitor were used in 40 cases who underwent thyroid surgery under general anesthesia from Nov. 2002 to May 2005. The endotracheal intubation with laryngeal electrode sited on the tube nerve integrity monitor were adopted for general anesthesia. The RLNs in 7 cases who underwent thyroid gland lobectomy were exposed and explored and not exposed in other operations. RESULTS: The function of RLNs in 39 cases remained well after-operation. Only 1 patient's left RLN was damaged during operation. The spontaneous non-in-phase CMAP (compound muscle action potential) of larynx muscle in both vocal cords were recorded in all 40 cases who underwent thyroid surgery under general anesthesia. The evoked in-phase CMAP of larynx muscle could be recorded while stimulating the exposed and explored RLNs by monopolar electrode. The minimal stimulus current intensity threshold ranged from 0.08 mA to 0.35 mA (average: 0.25 mA). The range of suitable stimulating current intensity was from 0. 2 mA to 1.0 mA. CONCLUSIONS: This technology had been proved to be more sensitive, voracious and stable. It can provide fore part precaution so that remarkably reduce the damage rate of RLN in surgery and avoid the dispensable medical dissection. It is not necessary to anatomies RLN in surgery in advance.

Adult↗

PubMed1994

AAEM minimonograph #42: intraoperative monitoring of peripheral and cranial nerves.

Intraoperative studies of focal neuropathies have become increasingly common both as an aid to the localization of the neuropathy and a means of monitoring the integrity of the nerve in the course of surgery. Success very often depends on careful attention to the technical problems presented by working in the operating theater. Despite these difficulties, assessment of conduction directly from the exposed nerve offers opportunities for better understanding the pathophysiology of these neuropathies and correlating these findings with conventional electrodiagnostic studies.

Action Potentials↗

PubMed1994

[New aspects in surgery of the thyroid gland with intraoperative monitoring of the recurrent laryngeal nerve].

A method for electrophysiological monitoring of the recurrent laryngeal nerve during thyroid surgery is described. An electromyographic record from the muscles of the vocal folds is obtained using two fine needle electrodes. The electrodes are placed endoscopically. The nerve is identified by electrical stimulation, and the electromyographic activity is registered using a Nerve Integrity Monitor NIM-2 (Xomed-Treace). Our experience with this method in 43 patients is described. The safety of the integrity of the recurrent laryngeal nerve is increased using intraoperative monitoring. This has led to a modification of the operative concept in thyroid surgery. Electrophysiological monitoring is mandatory in surgery of large goitres, retrotracheal and substernal extension, for re-operations and malignant diseases of the thyroid gland.

Electric Stimulation↗

PubMed2004

Intraoperative monitoring of kinetic total serum calcium levels in primary hyperparathyroidism surgery.

BACKGROUND: In the setting of minimal approach Sestamibi-guided parathyroid surgery for primary hyperparathyroidism we evaluated if total serum calcium level monitoring is as valuable as intraoperative parathyroid hormone (iPTH) monitoring. STUDY DESIGN: Prospective open single-blinded efficacy trial of two intraoperative diagnostic monitoring methods (iPTH and total serum calcium level) on a cohort of surgical patients. All patients (n = 35) were undergoing parathyroid surgery at the Department of General Surgery at B Cruces' Hospital, Vizcaya, Spain, between October 1999 and March 2001. Kinetics of serum levels of Ca and iPTH during surgery and time of prediction of cure for each method (measured in the clinic, admission, and intraoperatively, such as induction of anesthesia, and every 5 minutes after removal of adenoma) were analyzed. RESULTS: Hypercalcemia and iPTH levels became corrected in 34 patients. Average serum calcium levels dropped from pathologic 11.07 +/- 0.41 mg/dL (mean +/- standard deviation) to normal values 9.7 +/- 0.82 mg/dL during the first intraoperative determination (minute 5), but mean iPTH decreased from pathologic (192 +/- 98 pg/mL) to normal values (39.93 +/- 25.12 pg/mL) during the third intraoperative determination (minute 15). Serum calcium level at 5 minutes after removal decreased by 100% in 34 patients, but iPTH only showed a similar drop during the third determination at 15 minutes. Frozen sections were conclusive for parathyroid tissue (20.56 +/- 10.3 minutes after removal). CONCLUSIONS: Intraoperative measurement of total calcium level might be an easier and less expensive method than iPTH measurement in the prediction of cure during surgery for primary hyperparathyroidism resulting from adenoma.

Adenoma↗

PubMed1995

Intraoperative monitoring during selective posterior rhizotomy: technique and patient outcome.

We evaluated intraoperative electromyographic (EMG) results among 110 pediatric patients with spastic cerebral palsy who underwent selective posterior rhizotomy. We analyzed surgical outcomes for 60 of these patients who returned for follow-up assessment between 4 and 17 months postoperatively. Reduction in muscle tone (resistance to passive movement), increased range of motion and improvements in functional skills were seen at follow-up. To control for possible changes due to development, participation in therapy, or instability of measurements, 30 rhizotomy patients were evaluated twice during a baseline period of several months prior to surgery. No significant changes were found between these two measurement sessions during the baseline control period suggesting that the rhizotomy surgery itself caused the postoperative improvements. These intraoperative EMG monitoring techniques have been adopted at many other centers but variations in specific methods and EMG criteria have developed subsequently among major hospitals where selective posterior rhizotomy is performed. These variations in neurophysiologic methods and recent controversy about the usefulness of such intraoperative EMG monitoring created a need for us to publish our standard EMG selection technique. We describe here, in detail, methods for nerve rootlet testing and selection.

Cerebral Palsy↗

PubMed1997

Continuous intraoperative monitoring of middle cerebral artery blood flow velocities and electroencephalography during carotid endarterectomy. A comparison of the two methods to detect cerebral ischemia.

BACKGROUND AND PURPOSE: Intraoperative monitoring of brain function may influence the outcome of carotid endarterectomy (CEA). METHODS: We performed transcranial Doppler (TCD) monitoring of middle cerebral artery blood flow velocities (VMCAs) and eight-channel electroencephalographic (EEG) recording simultaneously in 82 patients undergoing CEA. Thiopental narcosis limited EEG interpretation in 11 patients, thus allowing direct comparison of both methods in 71 patients. RESULTS: There was a significant correlation between VMCA decrease and the frequency of EEG changes after carotid clamping (P < .001). Eight patients (11%) showed a VMCA decrease exceeding 60%, accompanied by EEG changes in 7 patients. Altogether, 16 patients (22%) showed severe or moderate EEG changes. Stenosis or occlusion of the contralateral carotid artery led to an increase of abnormal findings with both monitoring methods, which was, however, significant only for TCD (P < .05). Four patients (4.8%) suffered intraoperative transient ischemic attacks. In 3 of these patients, there were no abnormal findings with either of the methods. The events were thus unpredictable and probably of embolic origin. The fourth patient showed VMCA decrease to 0 and severe EEG changes. Nine patients had severe or moderate EEG changes without significant VMCA decrease and without complications. EEG monitoring alone in these would have led to unnecessary use of a shunt with the increased risk of embolism. CONCLUSION: EEG and TCD monitoring are complementary techniques. Their results showed a good overall correlation but with marked differences in the individual patient. TCD monitoring alone was sensitive enough to prevent ischemic intraoperative complications. EEG findings are of limited value when barbiturates are used.

Aged↗

PubMed2000

Intraoperative monitoring of recurrent laryngeal nerve function.

Intraoperative recurrent laryngeal nerve identification is sometimes difficult in reoperative cervical dissection or operation for inflammatory thyroid disorders. Three modalities have been described to intraoperatively assess nerve function: vocal cord visualization with fiberoptic bronchoscopy or direct laryngoscopy, electromyelographic surveillance of arytenoid muscle function, and cord function assessment with an electromyelogram-electrode endotracheal tube. Our study focused on patients requiring cervical dissection for thyroid or parathyroid disease in which intraoperative recurrent laryngeal nerve function was monitored by nerve stimulation with a concentric bipolar probe. Impulses were tracked via a specialized electrode-bearing endotracheal tube with signal transduction to a recording monitor. No operative nerve injuries occurred in the patients of our study group. This surveillance technique's several advantages include use of standard intubation techniques with no increase in operative time, nerve stimulation tracings that are quantifiable and reproducible with production of a permanent record, and less subjectivity due to observer variability. We believe these factors make the electromyelogram-electrode endotracheal tube approach to intraoperative recurrent laryngeal nerve assessment the optimal technique.

Electromyography↗

PubMed2003

Chiari I malformation: potential role for intraoperative electrophysiologic monitoring.

Intraoperative electrophysiologic monitoring can diminish the risk of neurologic injury by enabling the detection of injury at a time when it can be reversed or minimized. Although it is clear that in patients with cervical spine disease monitoring during surgery reduces the incidence of neurologic injury, almost no data are available regarding its utility in patients undergoing suboccipital decompression for Chiari I malformation. Patients with Chiari I malformation have caudal displacement of the cerebellar tonsils below the skull base, thereby creating a tight foramen magnum and cervical canal. Although the majority of pediatric neurosurgeons perform a bony decompression with duraplasty for symptomatic patients, there is much controversy regarding the amount of bony decompression required for clinical improvement and whether a duraplasty is essential. The authors therefore conducted a prospective, observational study using intraoperative brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials in pediatric patients undergoing suboccipital decompressions for Chiari I malformations to determine whether there were consistent changes in intraoperative BAEPs that could help the operating surgeon decide how extensive a decompression was needed in these patients, and whether changes in BAEPs or somatosensory evoked potentials occurred during operative positioning that could be modified to reduce the risk of neurologic injury.

Arnold-Chiari Malformation↗