Use Of Intraoperative Neurophysiological Monitoring Research Articles

Accuracy of Intraoperative Neuromonitoring in the Diagnosis of Intraoperative Neurological Decline in the Setting of Spinal Surgery-A Systematic Review and Meta-Analysis.

Systematic review and meta-analysis. In an effort to prevent intraoperative neurological injury during spine surgery, the use of intraoperative neurophysiological monitoring (IONM) has increased significantly in recent years. Using IONM, spinal cord function can be evaluated intraoperatively by recording signals from specific nerve roots, motor tracts, and sensory tracts. We performed a systematic review and meta-analysis of diagnostic test accuracy (DTA) studies to evaluate the efficacy of IONM among patients undergoing spine surgery for any indication. The current systematic review and meta-analysis was performed using the Preferred Reporting Items for a Systematic Review and Meta-analysis statement for Diagnostic Test Accuracy Studies (PRISMA-DTA) and was registered on PROSPERO. A comprehensive search was performed using MEDLINE, EMBASE and SCOPUS for all studies assessing the diagnostic accuracy of neuromonitoring, including somatosensory evoked potential (SSEP), motor evoked potential (MEP) and electromyography (EMG), either on their own or in combination (multimodal). Studies were included if they reported raw numbers for True Positives (TP), False Negatives (FN), False Positives (FP) and True Negative (TN) either in a 2 × 2 contingency table or in text, and if they used postoperative neurologic exam as a reference standard. Pooled sensitivity and specificity were calculated to evaluate the overall efficacy of each modality type using a bivariate model adapted by Reitsma et al, for all spine surgeries and for individual disease groups and regions of spine. The risk of bias (ROB) of included studies was assessed using the quality assessment tool for diagnostic accuracy studies (QUADAS-2). A total of 163 studies were included; 52 of these studies with 16,310 patients reported data for SSEP, 68 studies with 71,144 patients reported data for MEP, 16 studies with 7888 patients reported data for EMG and 69 studies with 17,968 patients reported data for multimodal monitoring. The overall sensitivity, specificity, DOR and AUC for SSEP were 71.4% (95% CI 54.8-83.7), 97.1% (95% CI 95.3-98.3), 41.9 (95% CI 24.1-73.1) and .899, respectively; for MEP, these were 90.2% (95% CI 86.2-93.1), 96% (95% CI 94.3-97.2), 103.25 (95% CI 69.98-152.34) and .927; for EMG, these were 48.3% (95% CI 31.4-65.6), 92.9% (95% CI 84.4-96.9), 11.2 (95% CI 4.84-25.97) and .773; for multimodal, these were found to be 83.5% (95% CI 81-85.7), 93.8% (95% CI 90.6-95.9), 60 (95% CI 35.6-101.3) and .895, respectively. Using the QUADAS-2 ROB analysis, of the 52 studies reporting on SSEP, 13 (25%) were high-risk, 10 (19.2%) had some concerns and 29 (55.8%) were low-risk; for MEP, 8 (11.7%) were high-risk, 21 had some concerns and 39 (57.3%) were low-risk; for EMG, 4 (25%) were high-risk, 3 (18.75%) had some concerns and 9 (56.25%) were low-risk; for multimodal, 14 (20.3%) were high-risk, 13 (18.8%) had some concerns and 42 (60.7%) were low-risk. These results indicate that all neuromonitoring modalities have diagnostic utility in successfully detecting impending or incident intraoperative neurologic injuries among patients undergoing spine surgery for any condition, although it is clear that the accuracy of each modality differs.PROSPERO Registration Number: CRD42023384158.

On temporary clipping in cerebral aneurysm surgery (literature review).

Temporary clipping (TC) of the parent artery is a standard procedure in cerebral aneurysm surgery. According to a number of studies, TC lasting up to 5 minutes is safe in terms of the development of ischemic complications. In cases where a longer TC is required, it is recommended to alternate vessel shutdown with periods of reperfusion, which allows the procedure to be repeated many times without the risk of ischemia. The article presents a review of current scientific publications on TC in cerebral aneurysm surgery, showing that this is a very unpredictable procedure in terms of the development of complications, even when performed within the recommended time parameters. There are cases of ischemia with TC lasting less than 5 minutes and the opposite situation, when TC lasting more than 10–20 minutes does not lead to the development of complications. The review also presents current ideas on how to improve the safety of TC, including the use of intraoperative neurophysiological monitoring.

Has intraoperative neuromonitoring changed the surgery for unruptured middle cerebral artery aneurysms? A retrospective comparative study

Intraoperative neurophysiological monitoring (IONM) represents one of the available technologies able to assess ischemia and aimed to improve surgical outcome reducing the treatment related morbidity in surgery for intracranial aneurysms. Many studies analyzing the impact of IONM are poised by the heterogeneity bias affecting the cohorts. We report our experience with IONM for surgery of unruptured middle cerebral artery (MCA) aneurysm in order to highlight its influence on functional and radiological outcome and surgical strategy. We retrospectively reviewed all MCA unruptured aneurysms treated between January 2013 and June 2021 by our institutional neurovascular team. Patients were divided into 2 groups according to the use of IONM. A total of 153 patients were included in the study, 52 operated on without IONM and 101 with IONM. The groups did not differ preoperatively regarding clinical status and aneurysm characteristics. Patients operated with IONM had better functional outcomes at discharge as well as at follow-up (p= 0.048, p=0.041) due to lower symptomatic ischemia and better radiological outcome due to lower rate of unexpected aneurysmal remnants (p= 0.0173). The introduction of IONM changed the use of temporary clipping (TeC), increasing its average duration (p= 0.01) improving the safety of dissecting and clipping the aneurysm. IONM in surgery for unruptured MCA aneurysm could improve the efficacy and safety of clipping strategy in the way it showed a role in changing the use of TeC and was associated to the reduction of unexpected aneurysmal remnants’ rate and improvement in both short- and long-term patient’s outcome.

Pediatric Intraoperative Neurophysiological Monitoring and Long-Term Outcomes in a Developing Country.

Pediatric intraoperative neurophysiological monitoring (IONM) has been shown to be effective in preventing and reversing postoperative neurological deficits in developed countries. There are currently no published studies from developing countries that describe neurophysiological findings and postoperative outcomes. Our study aims to address these gaps in children undergoing neurosurgical procedures in a single center. We conducted a retrospective study of case series of children who underwent IONM (2014-2020) in the State of Mexico, Mexico. Sociodemographic characteristics, IONM modalities, changes during procedures, and short-term and long-term postoperative results were recorded. Descriptive statistics were used. We included 35 patients (≤18 years of age), 57% (20/35) boys. A relative increase of up to 5 times in the use of IONM is observed from 2014 (5.7%) to 2020 (25.7%) in our center. The most frequent preoperative pathologies were located at the infratentorial cranium (40%), followed by the spine and spinal cord (37.1%). The IONM modalities were as follows: free-running EMG 94.3%, transcranial electrical stimulation motor-evoked potentials 91.4%, somatosensory-evoked potentials 85.7%, triggered EMG 28.6%, EEG 25.7%, and visual-evoked potentials 5.7%. Only in 8.3%, we did not obtain sufficient evoked potential baseline signals. At 24 hours postoperatively true negatives were 100%. Long-term follow-up was completed in 22/35 (63%) at 3 months, 12/35 (34.2%) at 6 months, and 5/35 (14.3%) at 12 months with progressive motor and sensory improvement. Pediatric multimodal IONM in neurosurgeries from a single center in a developing country is mainly used in pathologies of the posterior fossa, spine, and spinal cord, with true negatives in 100% of those monitored, preventing and avoiding postoperative sequelae.

A Global Review of the Perioperative Care of Patients With Aneurysmal Subarachnoid Hemorrhage Undergoing Microsurgical Repair of Ruptured Intracerebral Aneurysm.

To describe the perioperative care of patients with aneurysmal subarachnoid hemorrhage (aSAH) who undergo microsurgical repair of a ruptured intracerebral aneurysm. An English language survey examined 138 areas of the perioperative care of patients with aSAH. Reported practices were categorized as those reported by <20%, 21% to 40%, 41% to 60%, 61% to 80%, and 81% to 100% of participating hospitals. Data were stratified by Worldbank country income level (high-income or low/middle-income). Variation between country-income groups and between countries was presented as an intracluster correlation coefficient (ICC) and 95% confidence interval (CI). Forty-eight hospitals representing 14 countries participated in the survey (response rate 64%); 33 (69%) hospitals admitted ≥60 aSAH patients per year. Clinical practices reported by 81 to 100% of the hospitals included placement of an arterial catheter, preinduction blood type/cross match, use of neuromuscular blockade during induction of general anesthesia, delivering 6 to 8mL/kg tidal volume, and checking hemoglobin and electrolyte panels. Reported use of intraoperative neurophysiological monitoring was 25% (41% in high-income and 10% in low/middle-income countries), with variation between Worldbank country-income group (ICC 0.15, 95% CI 0.02-2.76) and between countries (ICC 0.44, 95% CI 0.00-0.68). The use of induced hypothermia for neuroprotection was low (2%). Before aneurysm securement, variable in blood pressure targets was reported; systolic blood pressure 90 to 120mmHg (30%), 90 to 140mmHg (21%), and 90 to 160mmHg (5%). Induced hypertension during temporary clipping was reported by 37% of hospitals (37% each in high and low/middle-income countries). This global survey identifies differences in reported practices during the perioperative management of patients with aSAH.

The Utilization of Intraoperative Neurophysiological Monitoring for Lumbar Decompression and Fusion Surgery in New York State.

Retrospective database analysis. To elucidate trends in the utilization of intraoperative neurophysiological monitoring (IONM) during elective lumbar surgery procedures and to investigate the association between the use of IONM and surgical outcomes. The routine use of IONM in elective lumbar spine procedures has recently been called into question due to longer operative time, higher cost, and other substitute advanced technologies. The Statewide Planning and Research Cooperative System database was accessed to perform this retrospective study. The trends of IONM use for lumbar decompression and fusion procedures were investigated from 2007 to 2018. The association between IONM use and surgical outcomes was investigated from 2017 to 2018. Multivariable logistic regression analyses, as well as propensity score matching (PS-matching), were conducted to assess IONM association in neurological deficits reduction. The utilization of IONM showed an increase in a linear fashion from 79 cases in 2007 to 6201 cases in 2018. A total of 34,592 (12,419 monitored and 22,173 unmonitored) patients were extracted, and 210 patients (0.6%) were reported for postoperative neurological deficits. Unadjusted comparisons demonstrated that the IONM group was associated with significantly fewer neurological complications. However, the multivariable analysis indicated that IONM was not a significant predictor of neurological injuries. After the PS-matching of 23,642 patients, the incidence of neurological deficits was not significantly different between IONM and non-IONM patients. The utilization of IONM for elective lumbar surgeries continues to gain popularity. Our results indicated that IONM use was not associated with a reduction in neurological deficits and will not support the routine use of IONM for all elective lumbar surgery.

Intraoperative neurophysiological monitoring in surgery of lumbar spinal stenosis

Background. Lumbar spinal stenosis is a pathological constriction of the central spinal canal, lateral pocket or intervertebral foramen. The complication rate of lumbar spinal stenosis surgery ranges from 10 to 24 %. In order to reduce the number of intraoperative and early postoperative complications accompanied by the development of neurological deficit, various techniques of intraoperative neurophysiological monitoring are used.Aim. Study of informativity of the use of intraoperative neurophysiological monitoring during surgical treatment of degenerative lumbar spinal stenosis based on the experience of the neurosurgical department of the Republican Clinical Hospital (Yoshkar‑Ola, Mari El Republic).Materials and methods. Thus, 69 decompressive‑stabilizing surgical interventions for degenerative lumbar spinal stenosis at the L3–L5 level, performed with intraoperative neurophysiological monitoring (free‑run electromyography, transcranial motor evoked potentials, somatosensory evoked potentials, triggered electromyography were included in the retrospective study).Results. During intraoperative neurophysiological monitoring transcranial motor evoked potentials from the legs was registered in all cases. Normal somatosensory evoked potentials were recorded in most cases, in 12 cases (17.4 %) baseline somatosensory evoked potentials were not registered due to preoperative neurological deficits and the presence of concomitant somatic pathology. 308 inserted pedicular screws were examined using the triggered electromyography. Muscle responses were registered in 31 (45 %) operations, 45 (14 %) screws. True negatives were registered with 29 (64.4 %), true positives were registered with 12 (26.7 %), and false positives were registered with 4 (8.9 %) screws. In the postoperative period no increase in motor and sensory neurological deficits was observed in all patients; no neurological signs of screw malpositioning were revealed.Conclusion. The use of multimodal intraoperative neurophysiological monitoring during surgical treatment of lumbar spinal stenosis reduces the risk of postoperative neurological complications.

ANAESTHETIC IMPLICATIONS OF NEUROPHYSIOLOGICAL MONITORING IN PAEDIATRIC PATIENTS UNDERGOING KYPHOSCOLIOSIS CORRECTION: A CASE SERIES

Kyphoscoliosis is a progressive disorder that requires to be corrected surgically before adolescence sets in. Intraoperative Neurophysiological Monitoring (IONM) has emerged as a standard practice because it signicantly reduces neurological morbidity. Although much has been written on IONM in adult spine surgery, very little has been published related to the neurological outcome in paediatric population with continuous IONM. We report three patient with Paediatric kyphoscoliosis who underwent correction and had continuous IONM done over six months at a tertiary care center. We recommend that effective use of IONM would involve a checklist to manage the changes in neurological signals and good teamwork of anesthesiologist, surgeon, and neurophysiologist to respond to these changes

Intraoperative neuromonitoring in spine surgery: Does it reduce neural complications? Current evidence

The objectives were to review the evidence on whether intraoperative neurophysiological monitoring (IONM) sensitively and specifically detects intraoperative neurologic injury during spine surgery and whether it reduces neurological complications in spine surgery. A systematic literature review and meta-analysis were conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and studies spanning 1990–2022 were searched. The diagnostic accuracy of somatosensory evoked potentials (SSEPs) and motor-evoked potential (MEP) in predicting postoperative neurologic outcomes in spine surgery was assessed. We also analyzed clinical comparative studies that compared patients who underwent spine surgery with and without IONM to determine the rate of new neurologic events. Fifty studies that provided exact SSEP or MEP changes and postoperative neurological outcomes were analyzed. The features of SSEP changes included low sensitivity (67.7%), high specificity (94.1%), and strong negative predictive value (NPV) (92.1%). For the assessed alarm criteria of a 50% reduction, a 65% reduction, an 80% reduction in amplitude, and a total signal loss, the sensitivity and specificity values for MEP were 87.4%, 100%, 100%, and 100%, and 94.8%, 97%, 94.5%, and 90.5%, respectively. A random effects model was used to assess six research that compared neurological events with and without the use of IONM. The pooled Odds ratio was 0.5746 (confidence interval = 0.48; 0.67), z = 6.637, and the P value was 0.0001. The usefulness of IONM in detecting neurological events during spine surgery is well demonstrated by a growing body of research. However, prospective trials with high-level data are lacking to establish its efficacy in preventing new neurological deficits.

ESTUDO SOBRE PACIENTES COM ESCOLIOSE PEDIÁTRICA NO HOSPITAL SANTA CASA DE MISERICÓRDIA DE SÃO PAULO

ABSTRACT Objective: To carry out registration of patients with scoliosis under 18 years old, followed in a quarternary hospital of high complexity, who need surgical treatment, aiming to identify the reasons for the delay in treatment. Methods: Data collection was carried out in person and by spontaneous demand at the spinal orthopedic specialty outpatient clinic in a tertiary hospital of high complexity from January 2021 to December 2022. The results were compiled in the networked database (Red Cap®). Result: 59 patients were evaluated, 45 female (77.9%) and 14 male (22.1%), with a mean age of 13.7 years. Etiology: 30 idiopathic (50.8%), eight syndromic (13.5%), 11 neuromuscular (18.6%), and ten congenital (16.9%). Of the total, 46 (77.9%) were awaiting surgery and 13 (22.1%) were undergoing conservative treatment. The main causes of treatment delay: unavailability of intraoperative neurophysiological monitoring (19 - 41.3%); unavailability of specific surgical material (16 - 34.8%); difficulty of referral to our institution (6 - 13.1%); loss to follow-up (3 - 6.5%) and limitation in casting making (2 - 4.3%). The mean time between diagnosis and the first consultation is 17.25 months (0 - 140). The average surgical wait until December/2022 was 38.4 months (1 - 156). Conclusion: There is a lack of assistance in the steps of monitoring and treatment in the public health system, from directing the patient with scoliosis to the specialized center to performing the surgical procedure, mainly due to limitations in the use of intraoperative neurophysiological monitoring and the unavailability of specific materials to perform highly complex surgeries. Therapeutic Studies - Investigating the Results of Treatment.

Intraoperative Neurophysiological Monitoring for Intradural Extramedullary Spinal Tumours.

Retrospective cohort study. Intraoperative neurophysiological monitoring (IONM) is widely used in spinal neurosurgery, particularly for intramedullary tumours. However, its validity in intradural extramedullary (IDEM) spinal tumours is less clearly defined, this being the focus of this study. We compared outcomes for patients that underwent resection of IDEM tumours with and without IONM between 2010 and 2020. Primary outcomes were postoperative American Spinal Injury Association (ASIA) scores. Other factors assessed were use of intraoperative ultrasound, drain placement, postoperative complications, postoperative Eastern Cooperative Oncology Group (ECOG) score, extent of resection, length of hospital stay, discharge location and recurrence. 163 patients were included, 71 patients in the IONM group and 92 in the non-IONM group. No significant differences were noted in baseline demographics. For preoperative ASIA D patients, 44.0% remained ASIA D and 49.9% improved to ASIA E in the IONM group, compared to 39.7% and 30.2% respectively in the non-IONM group. For preoperative ASIA E patients, 50.3% remained ASIA E and 44.0% deteriorated to ASIA D in the IONM group, compared to 30.2% and 39.7% respectively in the non-IONM group (all other patients deteriorated further). Length of inpatient stay was significantly shorter in the IONM group (P = .043). There were no significant differences in extent of resection, postoperative complications, discharge location or tumour recurrence. Research focusing on the use of IONM in IDEM tumour surgery remains scarce. Our study supports the use of IONM during surgical excision of IDEM tumours.

Successful enucleation of a large sciatic schwannoma with intraoperative neurostimulation-guided dissection: a case report

Advances in intraoperative neurophysiological monitoring (IONM) have enabled safer peripheral nerve tumor surgery. We report a patient in whom a large sciatic nerve schwannoma was successfully removed using intraoperative nerve stimulation. A 62-year-old male presented with a palpable mass in the right posterior upper thigh, just below the gluteal fold. Magnetic resonance imaging showed an approximately 9-cm encapsulated solid mass in the middle of the sciatic nerve. After a vertical skin incision with a laterally curved upper end extending to the inferior gluteal region, the proximal sciatic nerve was secured laterally to the biceps femoris and the distal nerve medial to the muscle. We avoided causing trauma to the viable nerve fascicles by dissecting through the “safe zone,” as confirmed by monitoring the distal muscle contractions induced by intraoperative nerve stimulation on the tumor surface. In this report, we present the details of our surgical approach to the middle portion of the sciatic nerve and the use of IONM for safe tumor excision.

Functional Outcome in Spinal Meningioma Surgery and Use of Intraoperative Neurophysiological Monitoring.

Data on intraoperative neurophysiological monitoring (IOM) during spinal meningioma (SM) surgery are scarce. The aim of this study was to assess the role of IOM and its impact on post-operative functional outcome. Eighty-six consecutive surgically treated SM patients were included. We assessed pre and post-operative Modified McCormick Scale (mMCS), radiological and histopathological data and IOM findings. Degree of cord compression was associated with preoperative mMCS and existence of motor or sensory deficits (p &lt; 0.001). IOM was used in 51 (59.3%) patients (IOM-group). Median pre and post-operative mMCS was II and I, respectively (p &lt; 0.001). Fifty-seven (66.3%) patients showed an improvement of at least one grade in the mMCS one year after surgery. In the IOM group, only one patient had worsened neurological status, and this was correctly predicted by alterations in evoked potentials. Analysis of both groups found no significantly better neurological outcome in the IOM group, but IOM led to changes in surgical strategy in complex cases. Resection of SM is safe and leads to improved neurological outcome in most cases. Both complication and tumor recurrence rates were low. We recommend the use of IOM in surgically challenging cases, such as completely ossified or large ventrolateral SM.

Facial Nerve Function After Microsurgical Resection in Vestibular Schwannoma Under Neurophysiological Monitoring.

BackgroundThe use of intraoperative neurophysiological monitoring, including direct nerve stimulation (especially the facial nerve), acoustic evoked potentials (AEP) and somatosensory evoked potentials (SSEP), is a helpful tool in the microsurgery of vestibular schwannoma to prevent nerve injury. Patient characteristics and intraoperative and postoperative variables might also influence the postoperative facial nerve function. The study was performed to investigate these variables and the intraoperative neurophysiological monitoring values.MethodsSeventy-nine patients with vestibular schwannoma were included consecutively into this study. Intraoperative neurophysiological monitoring, including SSEP, AEP, and direct nerve stimulation for facial and trigeminal nerve electromyography, was performed utilizing digital data storage in all cases. The intensity (in volts) of the direct stimulation and the latency (in ms) for the orbicularis oculi and the orbicularis oris muscle and the amplitude (in mV) was measured. Univariate and multivariate statistical analyses concerning the different parameters was performed directly after the operation and in the subsequent follow-ups 3 and 6 months after the operation.ResultsThe mean intensity was 0.79 V (SD.29). The latency and amplitude for the oris muscle was 5.2 ms (SD 2.07) and 0.68 mV (SD.57), respectively. The mean latency for the occuli muscle was 5.58 ms (SD 2.2) and the amplitude was 0.58 mV (SD 1.04). The univariate and multivariate statistical analyses showed significance concerning the postoperative facial nerve function and the amplitude of the direct stimulation of the facial nerve in the orbicularis oris muscle (p = 0.03), so repeated direct nerve stimulation might show FN function deterioration. The mean diameter of the tumors was 24 mm (range 10–57 mm). Cross total resection and near total was achieved in 76 patients (96%) and subtotal in three patients (4%). The preoperative House–Brakeman score (HBS) 1 was constant in 65 (82%) cases. The mortality in our series was 0%; the overall morbidity was 10%. The HBS was not influenced concerning the extent of resection. The mean follow-up was 28 months (range 6 to 60 months). The limitations of the study might be a low number of patients and the retrospective character of the study.ConclusionIntraoperative neurophysiological monitoring is crucial in vestibular schwannoma surgery. Repeated direct nerve stimulation and a detected decreased amplitude might show facial nerve function deterioration.

Surgery for intramedullary spinal cord ependymomas in the neuromonitoring era: results from a consecutive series of 100 patients.

The established treatment of intramedullary spinal cord ependymomas (ISCEs) is resection. Surgical series reporting treatment results often lack homogeneity, as these are collected over long time spans and their analysis is plagued by surgical learning curves and inconsistent use of intraoperative neurophysiological monitoring (IONM). The authors report the oncological and functional long-term outcomes in a modern series of 100 consecutive ISCEs that were resected between 2000 and 2015 by a surgically experienced team that consistently utilized IONM. In this retrospective study, the authors tailored surgical strategy and multimodal IONM, including somatosensory evoked potentials, muscle motor evoked potentials (mMEPs), and D-waves, with the aim of gross-total resection (GTR). Preservation of the D-wave was the primary objective, and preservation of mMEPs was the second functional objective. Functional status was evaluated using the modified McCormick Scale (MMS) preoperatively, postoperatively, and at follow-up. Preoperatively, 89 patients were functionally independent (MMS grade I or II). A GTR was achieved in 89 patients, 10 patients had a stable residual, and 1 patient underwent reoperation for tumor progression. At a mean follow-up of 65.4 months, 82 patients were functionally independent, and 11 lost their functional independence after surgery (MMS grades III-V). Muscle MEP loss predicted short-term postoperative worsening (p < 0.0001) only, while the strongest predictors of a good functional long-term outcome were lower preoperative MMS grades (p < 0.0001) and D-wave preservation. D-wave monitorability was 67%; it was higher with lower preoperative MMS grades and predicted a better recovery (p = 0.01). In this large series of ISCEs, a high rate of GTR and long-term favorable functional outcome were achieved. Short- and long-term functional outcomes were best reflected by mMEPs and D-wave monitoring, respectively.

Assessment of safe and gross total resection of intra-axial brain tumors

Background Safe and gross total resection (GTR) of intra-axial brain-tumor surgery is associated with improving functional outcomes, reducing symptoms, and decreasing the incidence of postoperative complications. Intraoperative imaging helps in achieving the maximum extent of resection. Intraoperative evaluation of the neurological function provides safe tumor resection in eloquent areas.Aim This study aimed to assess the achievement of GTR of intra-axial brain tumors guided by neuronavigation and intraoperative ultrasound and to evaluate the safety of tumor resection in eloquent areas with the use of intraoperative neurophysiological monitoring or awake craniotomy.Patients and methods This study included 30 patients with intra-axial brain tumors in the period from September 2019 to February 2021. Neuronavigation and intraoperative ultrasound were used for all cases, while intraoperative neurophysiological monitoring or awake craniotomy was used for intra-axial brain tumor in eloquent area. Operative details, outcomes, and final results had been recorded and analyzed.Results The mean age was 42 years (4–75 years). GTR was achieved in 18/30 (60%) of all cases. GTR was achieved in 4/10 (40%) of tumors located in the eloquent area, while GTR increased to 14/20 (70%) in noneloquent areas. The mean Karnofsky performance status for all cases has improved from 80 preoperatively to 86.67 postoperatively.Conclusion Neuronavigation and intraoperative ultrasound provides maximization of the extent of resection of intra-axial brain tumors. Intraoperative neurophysiological monitoring or awake craniotomy provides safe tumor resection in eloquent areas.

Functional Approaches to the Surgery of Brain Gliomas.

In the surgery of gliomas, recent years have witnessed unprecedented theoretical and technical development, which extensively increased indication to surgery. On one hand, it has been solidly demonstrated the impact of gross total resection on life expectancy. On the other hand, the paradigm shift from classical cortical localization of brain function towards connectomics caused by the resurgence of awake surgery and the advent of tractography has permitted safer surgeries focused on subcortical white matter tracts preservation and allowed for surgical resections within regions, such as Broca's area or the primary motor cortex, which were previously deemed inoperable. Furthermore, new asleep electrophysiological techniques have been developed whenever awake surgery is not an option, such as operating in situations of poor compliance (including paediatric patients) or pre-existing neurological deficits. One such strategy is the use of intraoperative neurophysiological monitoring (IONM), enabling the identification and preservation of functionally defined, but anatomically ambiguous, cortico-subcortical structures through mapping and monitoring techniques. These advances tie in with novel challenges, specifically risk prediction and the impact of neuroplasticity, the indication for tumour resection beyond visible borders, or supratotal resection, and most of all, a reappraisal of the importance of the right hemisphere from early psychosurgery to mapping and preservation of social behaviour, executive control, and decision making.Here we review current advances and future perspectives in a functional approach to glioma surgery.

Roles of multimodal intra-operative neurophysiological monitoring (IONM) in percutaneous endoscopic transforaminal lumbar interbody fusion: a case series of 113 patients

BackgroundDespite the wide use of intraoperative neurophysiological monitoring (IONM) in spinal surgeries, the efficacy of IONM during percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) surgery in detecting postoperative neurological deficits has not been well characterized.MethodsMIONM data from 113 consecutive patients who underwent PE-TLIF surgeries between June 2018 and April 2020 were retrospectively reviewed. Postoperative neurological deficits were documented and analyzed, and the efficacy and specificity of various IONM techniques were compared.ResultsOf the 113 consecutive patients, 12 (10.6%) with IONM alerts were identified. The MIONM sensitivity and specificity were 100 and 96.2%, respectively. The frequency of neurological complications, including minor deficits, was 6.2% (n = 7); all of the neurological complications were temporary. The ability of single IONM modalities to detect neurological complications varied between 25.0 and 66.6%, whereas that of all modalities was 100%.ConclusionsMIONM is more effective and accurate than unimodal monitoring in assessing nerve root function during PE-TLIF surgeries, reducing both neurological complications and false-negative findings. We recommend MIONM in PE-TLIF surgeries.

The use of intraoperative neurophysiological monitoring in dorsal resection of hemivertebrae

BACKGROUND: Congenital disorders of vertebrae formation are a common pathology in children. Intraoperative neurophysiological monitoring is a mandatory procedure, although it may not be effective enough due to the immature neural structures and the use of inhalation anesthetics in young children.&#x0D; AIM: To study aims to investigate the characteristic features of intraoperative neurophysiological monitoring in children with a congenital deformity of the spine during dorsal resection of the hemivertebrae.&#x0D; MATERIALS AND METHODS: 42 patients aged 117 years with a congenital deformity of the spine underwent 46 resections of the abnormal vertebra from an isolated dorsal approach (egg-shell technique). Intraoperative neurophysiological monitoring at the stages of the operation included a muscle relaxant test (TOF), transcranial electrical stimulation of the motor cortex (TCeMEP), control of the approach to the nerve (N. Proxy), correct placement of the pedicle screw (Screw Integrity), and EMG recording of the electromyogram. The accuracy of the screw placement was assessed by the Gerzbien method, and the presence of neurological disorders was tested by the Frenkel scale. The effect of inhalation anesthetic (sevoran) on motor evoked potentials was monitored by regulating its delivery, and the dependence on the age of patients was evaluated.&#x0D; RESULTS: The average age of patients was 7.7 4.5 years, and the TOF value was 80.5 17%. In 41 patients, the N. Proxy test was unremarkable, while in one patient, the 812 mA value did not require a change in the trajectory of the screws. From the beginning of sevoran and intraoperatively, motor evoked potentials from all tested muscles were recorded in 54.8% of patients; in children over 8 years old, this was observed in 92.8%, in children under 8 years old in 35.7% of cases in their age groups. In other patients, motor evoked potentials were most often not recorded from the muscles of the thigh and lower leg after sevoran administration. In children over 8 years old in 7.2%, under 8 years old in 83.3% of patients; Interestingly, in 7.2% of patients who are under 8 years of age, motor evoked potentials were not initially recorded from any muscle. Withdrawal of sevorane in 30.9% of patients allowed intraoperative motor evoked potentials to be obtained from all tested muscles in 100% of cases. For adequate management of anesthesia, 5 patients (50%) 14 years old and one patient 6 years old (5.6%) did not receive sevoran, and motor evoked potentials were recorded from the abdominal muscles. This allowed to assess the conduction only at the thoracic level and are required increased vigilance of surgeons when carrying out any corrective manipulations.&#x0D; CONCLUSIONS: Intraoperative neurophysiological monitoring with dorsal hemivertebra resection is an effective method that allows controlling the neurological complications during manipulations on the spine.

Holmes tremor: a delayed complication after resection of brainstem cavernomas.

In this paper, the authors aimed to illustrate how Holmes tremor (HT) can occur as a delayed complication after brainstem cavernoma resection despite strict adherence to the safe entry zones (SEZs). After operating on 2 patients with brainstem cavernoma at the Great Metropolitan Hospital Niguarda in Milan and noticing a similar pathological pattern postoperatively, the authors asked 10 different neurosurgery centers around the world to identify similar cases, and a total of 20 were gathered from among 1274 cases of brainstem cavernomas. They evaluated the tremor, cavernoma location, surgical approach, and SEZ for every case. For the 2 cases at their center, they also performed electromyographic and accelerometric recordings of the tremor and evaluated the post-operative tractographic representation of the neuronal pathways involved in the tremorigenesis. After gathering data on all 1274 brainstem cavernomas, they performed a statistical analysis to determine if the location of the cavernoma is a potential predicting factor for the onset of HT. From the analysis of all 20 cases with HT, it emerged that this highly debilitating tremor can occur as a delayed complication in patients whose postoperative clinical course has been excellent and in whom surgical access has strictly adhered to the SEZs. Three of the patients were subsequently effectively treated with deep brain stimulation (DBS), which resulted in complete or almost complete tremor regression. From the statistical analysis of all 1274 brainstem cavernomas, it was determined that a cavernoma location in the midbrain was significantly associated with the onset of HT (p < 0.0005). Despite strict adherence to SEZs, the use of intraoperative neurophysiological monitoring, and the immediate success of a resective surgery, HT, a severe neurological disorder, can occur as a delayed complication after resection of brainstem cavernomas. A cavernoma location in the midbrain is a significant predictive factor for the onset of HT. Further anatomical and neurophysiological studies will be necessary to find clues to prevent this complication.