Supratentorial Tumor Surgery Research Articles

Brain-Relaxing Effect of Different Diuretic Regimens in Supratentorial Tumor Surgery: A Comparative Study Guided by Optic Nerve Sheath Diameter.

Background:Hyperosmolar therapy is a well-established method to approach brain relaxation during craniotomy. Mannitol is used with a wide range of dosing regimens, combination with loop diuretics exerts a synergistic effect resulting in both reduction of the dose and its complications. Ultrasound measurement of optic nerve sheath diameter (ONSD) gives reliable information about intracranial pressure (ICP) and avoids overdosing and complications of osmotherapy.Aims and Objectives:In this study, we compare the ordinary dose of mannitol with the low dose combined with furosemide and detect the effect on ICP by ONSD.Setting and Design:This is a prospective, randomized, double-blind study involving 60 patients undergoing supratentorial brain tumor surgery.Materials and Methods:Sixty patients were enrolled in this study, divided into two equal groups: Group M received mannitol 1 g.kg−1: while Group F received mannitol 0.25 g.kg−1 and furosemide 0.5 mg.kg−1. Reduction in ONSD measurement was the primary objective, while brain-relaxation score (BRS), hemodynamic changes, urine output, serum lactate, and changes in serum electrolyte were the secondary objectives.Statistical Analysis:Data collected were analyzed using SPSS software, IBM, USA, version 22. P value was considered significant if <0.05.Results:ONSD and BRS showed no statistically significant difference between the studied groups. After diuresis, Group M showed significant reduction in heart rate and mean arterial blood pressure, serum sodium, potassium, and lactate (P = 0.02, P = 0.02, P = 0.001, P = 0.001, P = 0.001, P = 0.001 respectively), with increased urine output (UOP) and fluids replacement (P = 0.00, P = 0.01, respectively).Conclusion:Compared to high dose, adding loop diuretics to low-dose mannitol during supratentorial brain tumor surgeries resulted in comparable BRSs with a lower incidence of hemodynamic and metabolic disturbances.

Prophylactic antiepileptic treatment with levetiracetam for patients undergoing supratentorial brain tumor surgery: a two-center matched cohort study.

Guidelines on the administration of prophylactic antiepileptic drugs (AED), and specifically levetiracetam, for brain tumor surgery are still lacking. In this two-center matched cohort study, we aim to compare the proportion of postoperative seizures during follow-up after supratentorial tumor surgery in patients receiving no seizure prophylaxis, and those treated with levetiracetam perioperatively. Three hundred sixteen consecutive patients undergoing supratentorial tumor surgery, without history of seizures were included: 207 patients did not receive AED (no AED group), and 109 patients received levetiracetam perioperatively (levetiracetam group). The primary outcome measure was the rate of postoperative seizures. Additionally, uni- and multivariate analyses assessing possible risk factors for postoperative seizures were performed. No statistically significant difference for the occurrence of postoperative seizures was found between the two groups (10.1%, n = 21 in the no AED group vs. 9.2%, n = 10, in the levetiracetam group; p = 0.69, OR 0.9 [0.4-2.0), NNT 103 [12.9-17.1]). After propensity score matching, the primary outcome was observed in 13 patients (12.4%) from the no AED group and in 9 patients (8.6%) from the levetiracetam group (p = 0.50, OR 0.7 [0.3-1.6], NNT 26.3 [8.3-22.4]). Among all analyzed possible risk factors for postoperative seizures, only postoperative infarction showed a statistically significant association with higher seizure rates in multivariate analysis (OR 8.2 [1.1-60.6], p = 0.04). Prophylactic treatment with levetiracetam after brain tumor surgery showed no statistically significant effect in preventing postoperative seizures. However, in case a postoperative infarction occurs, its administration might be indicated.

Postoperative navigated transcranial magnetic stimulation to predict motor recovery after surgery of tumors in motor eloquent areas

ObjectiveTo know whether motor deficits after tumor surgery are transient is reassuring for the patient and crucial for planning rehabilitation and adjuvant treatment. We analyze the value of postoperative MRI navigated transcranial magnetic stimulation (nTMS) compared to intraoperative MEP monitoring in predicting recovery of motor function. MethodsRetrospective series of nTMS mappings within 14 days after surgery for supratentorial tumors (09/2014–05/2018). All patients with motor deficits of Medical-Research-Council-Grade (MRCS) 0–4- were included. ResultsWe performed nTMS mapping on average 3.8 days after surgery and recorded nTMS MEP in 11 of 13 patients. Motor strength recovered to at least MRCS 4 within one month if postoperative nTMS elicited MEPs (positive predictive value 90.9%). If nTMS did not elicit MEPs, the patient did not recover (negative predictive value 100%). Intraoperative MEP and postoperative nTMS were equally predictive for long-term motor recovery. In cases of intraoperative MEP alteration/signal loss, but a positive postoperative nTMS mapping, 2/3 patients demonstrated a good motor recovery. ConclusionnTMS may predict long-term motor recovery of patients suffering from severe motor deficits directly after resection of tumors located in motor eloquent areas. SignificanceIn cases of intraoperative MEP alterations, postoperative nTMS may clarify the potential for motor recovery.

Analgesia nociception index and hemodynamic changes during skull pin application for supratentorial craniotomies in patients receiving scalp block versus pin-site infiltration: A randomized controlled trial.

Background:Noxious stimulation such as skull pin insertion for craniotomy elicits a significant hemodynamic response. Both regional analgesic techniques (pin-site infiltration [PSI] and scalp block [SB]), and systemic strategies (opioids, alpha-2 agonists, anesthetics, and beta-blockers) have shown to attenuate this response. Analgesia Nociception Index (ANI) provides objective information about the magnitude of nociception and adequacy of analgesia. This study compared ANI and hemodynamic changes in patients receiving local anesthetic SB versus PSI during skull pin application for craniotomy.Materials and Methods:Sixty adult patients scheduled for elective supratentorial tumor surgery were randomly allocated to receive local anesthetic SB or PSI for skull pin insertion after the induction of anesthesia. Data regarding heart rate (HR), blood pressure (BP), and ANI were collected every minute for 5 min after the skull pin insertion beginning from the baseline.Results:A significant difference was observed in ANI values between the SB (higher ANI) and the PSI groups during skull pin insertion, P < 0.001 and P = 0.003 for ANIi and ANIm, respectively. Similarly, a significant difference was seen in HR and BP both within and between the two groups during skull pin insertion (P < 0.001 for both). The magnitude and duration of change were smaller in the SB group compared with the PSI group for the parameters studied. A strong negative linear correlation was noted between ANI and hemodynamic parameters.Conclusions:The changes in HR, BP, and ANI were significantly less with local anesthetic SB compared with PSI during skull pin insertion in patients undergoing supratentorial craniotomy.

Piezosurgery for Infra- and Supratentorial Craniotomies in Brain Tumor Surgery

Piezoelectric surgery represents an innovative technique to perform safe and effective osteotomies and is an alternative to traditional bony tissue management using rotating or perforating instruments. We evaluated the safety and feasibility of craniotomies using an ultrasonic device that allows the selective cut of mineralized structures, avoiding damages to the vascular, dural, and parenchymal structures. We analyzed a series of 300 patients (age range, 1-81 years; SD ± 15.2) who underwent elective cranial surgery for brain tumors, in which the craniotomy was performed using a piezoelectric device. Pre- and postoperative imaging, clinical notes, and intraoperative details were collected. There were 197 patients (66%) who underwent surgery for supratentorial tumors; the remaining 103 patients (34%) underwent surgery for infratentorial ones. Tumors involved the skull base in 125 cases. Meningiomas, gliomas, and schwannomas represented the most common histotypes. Duraplasty for dural damages was not necessary in all cases; no venous sinuses or parenchymal injuries were reported during bone work. We noted in 13 cases (4.3%) a minor dural tear, requiring only direct sutures. Bone flaps were always intact after craniotomy. No subgaleal cerebrospinal fluid (CSF) collection or CSF leak was recorded. Because of the minimal bone gap, we always achieved correct bone flap ossification. No reabsorption or mobilization of bone flap was noted. We illustrate the feasibility and safety of a piezosurgical cutter to perform craniotomies. This alternative technique appears to be safe, with excellent cosmetic effects, adding another tool to the neurosurgical armamentarium.

Analgesia Nociception Index-guided intraoperative fentanyl consumption and postoperative analgesia in patients receiving scalp block versus incision-site infiltration for craniotomy

Scalp block or local anesthetic infiltration for craniotomy blunts hemodynamic response to noxious stimuli, reduces opioid requirement and decreases postoperative pain. Analgesia Nociception Index (ANI) provides objective information about the magnitude of pain (rated from 0 to 100 with 0 indicating extreme nociception and 100 indicating absence of nociception) and adequacy of intra-operative analgesia. This study compared intra-operative fentanyl consumption guided by ANI and postoperative pain in patients who receive scalp block with those who receive incision-site local anesthetic infiltration for craniotomy. Sixty adult patients undergoing elective supra-tentorial tumor surgery were randomly allocated to receive scalp block or incision-site infiltration after induction of anesthesia. Throughout the intra-operative period, patients received fentanyl 0.5 µg/kg/h and ANI was continuously monitored. Fentanyl 1 µg/kg bolus was administered when ANI decreased to <50. Intraoperative fentanyl consumption was compared using unpaired t-test. Correlation between ANI and postoperative numerical rating scale (NRS) pain score was done using Spearman's rho. The fentanyl consumption (µg/kg/h) was less with scalp block when compared to incision-site infiltration (median [interquartile range]; 1.04 [0.92-1.34] vs. 1.34 [1.18-1.59], P=0.001). Postoperative pain scores were similar [median (interquartile range); 1.5 (0-4) vs. 3 (0-4), P=0.840]. No correlation was observed between postoperative NRS Score and ANI (correlation coefficient = 0.072; P=0.617). ANI-guided analgesic administration during craniotomy demonstrated lower intra-operative fentanyl consumption in patients receiving scalp block as compared to incision-site local anesthetic infiltration. No correlation was seen between postoperative NRS and ANI.

Effects of an Intraoperative Dexmedetomidine Bolus on the Postoperative Blood Pressure and Pain Subsequent to Craniotomy for Supratentorial Tumors.

Control of emergence hypertension and pain is important after craniotomy for monitoring the neurological status. This prospective double-blinded study investigated the hemodynamics after a single bolus of dexmedetomidine (DEX) infusion administered to the patient undergoing craniotomy under general anesthesia, and its effect on emergence hypertension and postsurgical pain. Adult patients scheduled for elective surgery for supratentorial tumors were randomized to receive a 10-minute intraoperative DEX infusion of 0.4 μg/kg (small dose, n=43) or 0.8 μg/kg (medium dose, n=46), or normal saline (vehicle control, n=45), ∼60 minutes before the end of anesthesia. A transient increase in the blood pressure associated with DEX was observed; 53.5% and 91.3% of the patients in the small-dose and the medium-dose groups, respectively, required treatment. Emergence mean arterial pressure and heart rates were significantly lower in the DEX groups compared with the control group. Incidence rates of postoperative hypertension in the small-dose (16.3%) and the medium-dose groups (15.2%) were significantly lower relative to that of the control group (35.6%). Patients who received DEX had a lower Verbal Numerical Rating Scale (VNRS) score in the neurosurgical ICU than the control group, and postsurgical pain (VNRS≥4) was lower in the medium-dose group (41.3%) than in the control group (71.1%). No shivering was observed in the medium-dose group, which was significantly less than that of the other 2 groups. An intraoperative bolus of DEX risks a transient increase in mean arterial pressure, but controls emergence hypertension effectively. Dose-related reductions in postsurgical pain and shivering were observed.

Effective and safe mannitol administration in patients undergoing supratentorial tumor surgery: A prospective, randomized and double blind study

ObjectivesAlthough osmotic diuresis with mannitol is commonly used to provide brain relaxation, there is no consensus regarding its optimal dose and combination with loop diuretics. The aim of the present study is to evaluate the effects of mannitol and combination of furosemide with different doses of mannitol on brain relaxation and on blood electrolytes, lactate level, urine output, fluid balance and blood osmolarity in patients undergoing supratentorial tumor surgery. Patients and methodsThis prospective, randomized, double blind, placebo-controlled study included 51 patients (ASA I–III) scheduled for elective supratentorial craniotomy. Different doses and combinations of diuretics were administered after the bone flap removal. The Group 1 received mannitol at 0.5gkg−1 and furosemide at 0.5mgkg−1, the Group 2 received mannitol at 1gkg−1 and furosemide at 0.5mgkg−1, and the Group 3 received mannitol at 0.5gkg−1 and placebo. The primary end-point of the present study is to evaluate the effects of mannitol and combination of furosemide with different doses of mannitol on brain relaxation and the secondary end-points are to evaluate their effects on blood electrolytes, lactate level, urine output, fluid balance and blood osmolarity. ResultsThis study shows that mannitol alone (0.5gkg−1), and the combinations of furosemide (0.5mgkg−1) with different doses of mannitol (0.5gkg−1–1gkg−1) provides adequate brain relaxation. However, administration of furosemide with low or high doses of mannitol may cause reduction in the sodium and chloride levels as well as rise in the lactate level. Moreover it may cause high urine output and negative intra-operative fluid balance. ConclusionAdministration of 0.5gkg−1 mannitol provides adequate brain relaxation without causing systemic side effects in patients undergoing supratentorial tumor surgery.This study is registered to clinical trials (Clinical Trials.gov identifier NCT02712476).

Erratum to: Same-day discharge after craniotomy for supratentorial tumour surgery: a retrospective observational single-centre study.

Enhanced Recovery After Surgery is a multimodal perioperative care pathway designed to achieve early discharge in patients undergoing major surgery. Recent advances in neurosurgery allow for shorter duration of anesthesia and surgery, faster recovery, and earlier discharge from hospital. The purpose of this retrospective observational study was to assess the incidence of early discharge from hospital in patients undergoing craniotomy for supratentorial brain tumours as well as to explore the associated perioperative factors, anesthesia techniques, and complications. The medical records of all patients who underwent craniotomy (less than four-hour duration) for supratentorial tumour over a five-year period were retrospectively reviewed. The data analyzed included the postoperative discharge destination, type of anesthesia—i.e., general anesthesia (GA) vs awake craniotomy (AC), and the incidence of adverse events. Data from 329 patients [mean (SD) age 48 (12) yr; 164 male, 165 female] were analyzed, including 198 (AC, n = 157; GA, n = 41) patients who were preoperatively scheduled for same-day discharge. Successful same-day discharge occurred in 175/198 (88.4%) of these patients (AC, n = 139; GA, n = 36). Five (2.9%) of the 175 patients (4 AC, 1 GA) with same-day discharge required readmission to hospital within the first 12 hr after discharge. Six (1.8%) of the 329 total patients had a documented postoperative intracranial bleed, but none occurred after initial discharge from hospital. Same-day discharge from hospital is possible in carefully selected patients after both GA and AC for supratentorial tumour surgery.

Infusion dose requirement of rocuronium in patients on phenytoin therapy - A prospective comparative study.

Background and Aims:Patients with intracranial tumour are usually on anticonvulsants. Patients on phenytoin therapy demonstrate rapid metabolism of nondepolarising muscle relaxants secondary to enzyme induction. Infusion dose requirement of rocuronium in such patients has been sparingly studied. We studied the continuous infusion dose requirement of rocuronium bromide in patients on phenytoin therapy and its correlation with serum levels of phenytoin.Methods:Seventy-five patients scheduled for supratentorial tumour surgery were included in the study. Patients not on phenytoin were taken as control. The primary outcome variable studied was the infusion dose requirement of rocuronium in patients on phenytoin. Based on pre-operative serum phenytoin levels, study group patients were divided into two groups: sub-therapeutic level group (phenytoin level <10 μg/mL) and therapeutic level group (phenytoin level >10 μg/mL). Following anaesthesia induction, rocuronium bromide 0.6 mg/kg was administered to achieve tracheal intubation. Rocuronium infusion was titrated to maintain zero response on the train-of-four response.Results:Demographic data were comparable. Patients receiving phenytoin required higher infusion dose compared to the control group (0.429 ± 0.2 mg/kg/h vs. 0.265 ± 0.15 mg/kg/h, P < 0.001). The serum phenytoin level had no correlation to infusion dose requirement of rocuronium (0.429 ± 0.205 mg/kg/h vs. 0.429 ± 0.265 mg/kg/h (P = 0.815). The recovery was faster in the phenytoin group compared to the control group. Haowever, it was not clinically significant.Conclusion:The infusion dose requirement of rocuronium bromide in patients on phenytoin is higher and the serum levels of phenytoin does not influence the dose required.

Lidocaine Reduces Acute Postoperative Pain After Supratentorial Tumor Surgery in the PACU: A Secondary Finding From a Randomized, Controlled Trial.

Perioperative lidocaine infusion has been reported to reduce postoperative pain in patients after abdominal surgery; however, no study has examined lidocaine's effect on acute postoperative pain after supratentorial tumor surgery. A total of 94 patients scheduled for supratentorial craniotomy were enrolled. Patients received either lidocaine through an intravenous bolus (1.5 mg/kg) after induction followed by infusion at a rate of 2 mg/kg/h until the end of surgery or the same volume of normal saline. Mean arterial blood pressure, heart rate, and bispectral index were recorded at different intraoperative time points. Patients were assessed for pain in the postoperative anesthesia care unit (PACU) by the numeric rating scale (NRS). Other complications including hypertension, tachycardia, dysphoria, and postoperative nausea and vomiting (PONV) were reported. There was no significant difference between the normal saline and lidocaine group for mean arterial blood pressure, heart rate, and bispectral index at any time point (P>0.05). There was no significant difference in the incidence of hypertension, tachycardia, dysphoria, and PONV between groups (P>0.05). The incidence of mild pain (NRS between 1 and 3) after surgery in PACU was lower in lidocaine group than that in the normal saline group (P=0.014); the number of patients with an NRS pain score of 0 before leaving the PACU was significantly greater in the lidocaine group. No patient in either group had moderate or severe pain. Intraoperative infusion of lidocaine significantly decreases the proportion of patients with acute pain after supratentorial tumor surgery in the PACU.

Same-day discharge after craniotomy for supratentorial tumour surgery: a retrospective observational single-centre study.

Enhanced Recovery After Surgery is a multimodal perioperative care pathway designed to achieve early discharge in patients undergoing major surgery. Recent advances in neurosurgery allow for shorter duration of anesthesia and surgery, faster recovery, and earlier discharge from hospital. The purpose of this retrospective observational study was to assess the incidence of early discharge from hospital in patients undergoing craniotomy for supratentorial brain tumours as well as to explore the associated perioperative factors, anesthesia techniques, and complications. The medical records of all patients who underwent craniotomy (less than four-hour duration) for supratentorial tumour over a five-year period were retrospectively reviewed. The data analyzed included the postoperative discharge destination, type of anesthesia-i.e., general anesthesia (GA) vs awake craniotomy (AC), and the incidence of adverse events. Data from 329 patients [mean (SD) age 48 (12) yr; 164 male, 165 female] were analyzed, including 198 (AC, n = 157; GA, n = 41) patients who were preoperatively scheduled for same-day discharge. Successful same-day discharge occurred in 175/198 (88.4%) of these patients (AC, n = 139; GA, n = 36). Five (2.9%) of the 175 patients (4 AC, 1 GA) with same-day discharge required readmission to hospital within the first 12 hr after discharge. Six (1.8%) of the 329 total patients had a documented postoperative intracranial bleed, but none occurred after initial discharge from hospital. Same-day discharge from hospital is possible in carefully selected patients after both GA and AC for supratentorial tumour surgery.

A novel threshold criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway.

OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.

Lidocaine Did Not Reduce Neuropsychological-Cognitive Decline in Patients 6 Months After Supratentorial Tumor Surgery: A Randomized, Controlled Trial.

: There is equivocal evidence examining cognitive improvement in response to lidocaine during cardiac surgery; however, no study has examined its effect on postoperative neuropsychological-cognitive decline after supratentorial tumor surgery. Ninety-four patients scheduled for supratentorial craniotomy were enrolled. Patients received either a dose of lidocaine (2%) via an intravenous bolus (1.5 mg/kg) after induction followed by an infusion at a rate of 2 mg/kg/h until the end of surgery (Lidocaine group) or the same volume of normal saline. The neuropsychological-cognitive decline was evaluated using the following tests: the Mini-Mental State Examination, the Information-Memory-Concentration test, the Hamilton Rating Scale for Depression, and the Hamilton Rating Scale for Anxiety. The cerebral oxygen extraction ratio and the difference in lactic acid levels between the bulb of the jugular vein and a peripheral artery were measured. Eighty patients completed the neuropsychological tests, with 40 patients in each group. The incidence of postoperative decline at up to 6 months in the Lidocaine group was not significantly different than that in the Normal saline group. When the 2 cognitive tests were examined independent of the other tests, there was no difference between groups at 6 months. The cerebral oxygen extraction ratio was significantly lower in the Lidocaine group after surgery (P<0.05), and the arteriovenous difference of lactic acid was lower in the Lidocaine group (P<0.05). Intraoperative infusion of lidocaine does not significantly decrease the incidence of postoperative neuropsychological-cognitive decline in patients 6 months after supratentorial tumor surgery.

Comparison of equiosmolar concentrations of hypertonic saline and mannitol for intraoperative lax brain in patients undergoing craniotomy.

Background:Osmotherapy is the frequently used for the treatment of intracranial pressure. The purpose of the study was to compare the effect of equiosmolar solution of 3% hypertonic saline and 20% mannitol on brain relaxation in supratentorial tumor surgery.Methods:After institutional review board approval and written informed consent, 50 patients aged >18, Glasgow Coma Scale (GCS) >13 with ASA physical status 1, 2, and 3 scheduled to undergo craniotomy for supratentorial tumors were enrolled in this prospective, randomized study. Patients received 5 ml/kg of either 3% hypertonic saline (n = 25) or 20% mannitol (n = 25). Hemodynamic variables (heart rate [HR], SBP, DBP, MBP, and central venous pressure [CVP]), serum electrolytes, serum osmolality, urine output, and fluid balance were measured. The surgeon assessed the brain condition on four point scale (1 = perfectly relaxed, 2 = satisfactorily relaxed, 3 = firm brain, and 4 = bulging brain), who was blinded to study drug.Results:Brain relaxation was comparable in two groups and there was no significant difference (P = 0.633). The number of brain conditions classified as perfectly relaxed, satisfactorily relaxed, firm brain, and bulging brain in the HS group was 8, 13, 3, and 1, respectively, whereas it was 5, 17, 3, and 0, respectively, in the M group. There was no significant difference in hemodynamic variables between the two groups except CVP at 30 min (P = 048). Compared with mannitol, hypertonic saline caused increase in the serum osmolality at 120 min (P = 0.008) and in serum sodium at 120 min (P = 0.001). Urine output was higher with mannitol than hypertonic saline (P = 0.001).Conclusion:3% hypertonic saline and 20% mannitol are equally effective for brain relaxation in elective supratentorial tumor surgery and compared with mannitol, hypertonic saline was associated with less diuretic effect.

S40: Intraoperative neurophysiological monitoring in pediatric neurosurgery: a focus on the sacral system

s of Speakers / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339 S9 anodal direct cortical stimulation, activates the corticospinal tract close to the axon hillock at the border between the grey and the white matter. DCS remains the most focal stimulation possible and thus is favorable used for tumor removal within the vicinity of the motor cortex. MEPs became focus of neurooncological strategies for optimized glioma resection. Combining DCS-MEPs and monopolar cortical/subcortical stimulation mapping techniques in supratentorial tumor surgery as well as combination with intraoperative imaging could achieve supramarginal resection. The proposed subcortical stimulation motor threshold of 2 mA for safe resection has to be confirmed with regard to tumor type and precise location of stimulation. As been shown in cerebral aneurysm surgery, the ability to detect pure motor hemiparesis in carotid endarterectomy was more recently shown in a multicenter study. In spine surgery, presence or disappearance (“all-or-nothing” principle) of MEP amplitude criteria is commonly accepted: the presence of any MEPs is related to unaffected motor function or transient paresis, with the exception of radiculopathy. In cervical and thoracic intramedullary spinal cord surgery, the additional implementation of the D-wave helps to distinguish between permanent and transient motor deficit: D-wave preservation is always followed by a recovery of motor function. The latter seems to be applicable in supratentorial surgeries alike. In summary, MEPs are specific and sensitive for the assessment of the motor cortex and the corticospinal tract. In supratentorial tumor surgery MEPs are increasingly becoming a tool for “functional” guided resection strategies. S40 Intraoperative neurophysiological monitoring in pediatric neurosurgery: a focus on the sacral system F. Sala1, G. Squintani2, V. Tramontano2, C. Arcaro1 1Institute of Neurosurgery, Verona, Italy; 2Division of Neurology, Neurosciences, Verona, Italy Introduction: Intraoperative neurophysiologic monitoring (IOM) is nowadays extensively used in Pediatric Neurosurgery and tethered cord surgery is one of the most useful application. Our goal is to describe and discuss the standard IOM techniques used during tethered cord surgery, in the light of our clinical experience over the past ten years. Material and methods: Neurophysiological mapping of the conus-cauda is performed through direct stimulation of these structures and bilateral recording from segmental target muscles. While mapping identify ambiguous neural structures, their functional integrity during surgery can be assessed by monitoring techniques only, such as somatosensory evoked potentials (SEPs), transcranial motor evoked potentials (MEPs) from limb muscles and anal sphincters, and the bulbocavernosus reflex (BCR). Results: Between 2002 and 2012, we performed 48 surgical procedures in 47 patients with a tethered cord secondary to a variety of spinal dysraphisms. The monitorability rate was 84% for SEPs, 97% for limb muscle MEPs, 74% for the anal sphincter MEPs, and 59% for the BCR. In all patients but one SEP, MEP and BCR remained stable during surgery. Post-operatively two out of 47 patients presented a significant – though transient – neurological worsening. In six patients an unexpected muscle response was evoked by stimulating tissue macroscopically considered as not functional. Conclusions: Mapping techniques allow to identify and spare functional neural tissue and, vice-versa, to cut non-functional structures that may contribute to cord tethering. Monitoring techniques, MEP and BCR in particular, improve the reliability of intraoperative neurophysiology. IOM minimizes neurological morbidity in tethered cord surgery. S41 Neurophysiology of congenital mirror movements

O38: Subcortical mapping and intraoperative diffusion tensor tractography 3.0T of the corticospinal tract in supratentorial intrinsic tumor surgery. Reliability study

O38: Subcortical mapping and intraoperative diffusion tensor tractography 3.0T of the corticospinal tract in supratentorial intrinsic tumor surgery. Reliability study

50. Subcortical mapping and intraoperative DTT 3.0T of the corticospinal tract in supratentorial intrinsic tumor surgery. What should we rely on?

Introduction The course of the corticospinal tract (CST) can be identified using subcortical mapping (sc-MEP). The threshold technique (MEP-trsh) is considered to be reliable in setting the safe zone. Intraoperative DTT and sc-MEP correlation is thought to be more precise because of brainshift elimination. Goal of the study Evaluate intraoperative DTT 3.0T reliability comparing to CST mapping in nonselected patient series. Methods 25 patients were enrolled consecutively and prospectively from 7/2010 to 7/2012. Inclusion criteria: solitary supratentorial intracerebral lesion compressing or infiltrating the CST. Sc-MEP was performed by monopolar (cathodal) stimulation (500 Hz, 400 μ s, 5 pulses) with navigated probe. CST DTT was made both at preoperative and intraoperative 3.0T MRI. MEP-trsh current and probe-CST distance were recorded at 155 points before iMRI (preoperative scans), and at 103 points after iMRI (intraoperative scans). Current-distance correlations were performed both for pre-iMRI and for post-iMRI data separately. Results The correlation coefficient pre-iMRI was R = 0.470 (p 0.001), post-iMRI was R = 0.338 (p 0.001). MRI radical resection was achieved in 17 (68%), subtotal in 5 (24%) and partial in 3 (12%). Postoperative paresis developed in 8 (32%), permanent remained in one case (4%). Intraoperative DTT was unreliable because of image distortion in 9 (36%). Conclusion The linear current-distance correlation was found both in pre-iMRI and in post-iMRI data. Correlation of post-iMRI data was weaker. Intraoperative DTT was unreliable in 36%. Sc-MEPs remains superior, because of direct mapping of neural fibers and lack of technical failure. Supported by IGA MZ CR 12253–5.

2. Subcortical mapping and intraoperative DTT 3.0 T of the corticospinal tract in supratentorial intrinsic tumour surgery. What should we rely on?

Intraoperative subcortical mapping of the corticospinal tract (CST) using the threshold technique (sc-MEPs) is considered to be helpful during tumour resection adjacent to the CST. Diffusion tensor tractography (DTT) of the CST is feasible. Intraoperative DTT and sc-MEP correlation is thought to be more precise because of brainshift elimination. The goal of the study was to evaluate intraoperative DTT 3.0 T reliability compared with CST mapping in a nonselected series. 25 patients were enrolled consecutively and prospectively between June 2010 and June 2012. Inclusion criteria: solitary supratentorial intracerebral lesion compressing or infiltrating the CST according to preoperative MRI. Subcortical CST mapping was performed by monopolar (cathodal) stimulation (500 Hz, 400Î1/4s, 5 pulses) with a navigated probe. CST DTT was performedon both preoperative and intraoperative 3.0 T MRI. sc-MEP threshold current and probe-CST distance were recorded at 155 points before iMRI (intraoperative MRI) (preoperative scans) and at 103 points after iMRI (intraoperative scans). Current-distance correlations were performed both for pre-iMRI and for post-iMRI data separately. The correlation coefficient between pre-iMRI data was R = 0.470 (p < 0.001), post-iMRI data was R = 0.338 (p < 0.001). MRI radical resection was achieved in 17 (68%), subtotal in 5 (24%) and partial in 3 (12%). Postoperative paresis developed in 8 (32%), but was permanent in only one case (4%). The lowest sc-MEP threshold was ⩽ 5.0 mA in 10 (40%); 5–10.0 mA in 9 (36%); > 10.0 mA in 6 patients (24%). Intraoperative DTT became unreliable because of severe image distortion in 9 (36%). The linear current-distance correlation was found both in pre-iMRI and in post-iMRI data. Correlation of post-iMRI data was weaker. Neurophysiological subcortical mapping was more reliable intraoperatively than DTT. Combining these two methods can help increase the safety of tumour resection close to the CST only in selected cases. Supported by IGAMZCR12253-5.

Intraoperative monitoring of motor-evoked potentials for supratentorial tumor surgery.

ObjectiveThe purpose of this study was to assess the feasibility and clinical efficacy of motor evoked potential (MEP) monitoring for supratentorial tumor surgery.MethodsBetween 2010 and 2012, to prevent postoperative motor deterioration, MEP recording after transcranial stimulation was performed in 84 patients with supratentorial brain tumors (45 males, 39 females; age range, 24-80 years; median age, 58 years). MEP monitoring results were correlated with postoperative motor outcome compared to preoperative motor status.ResultsMEP recordings were stable in amplitude (<50% reduction in amplitude) during surgery in 77 patients (91.7%). No postoperative motor deficit was found in 66 out of 77 patients with stable MEP amplitudes. However, postoperative paresis developed in 11 patients. False negative findings were associated with edema in peri-resectional regions and postoperative bleeding in the tumor bed. MEP decrease in amplitude (>50%) occurred in seven patients (8.3%). However, no deficit occurred postoperatively in four patients following preventive management during the operation. Three patients had permanent paresis, which could have been associated with vascular injury during tumor resection.ConclusionsMEP monitoring during supratentorial tumor surgery is feasible and safe. However, false negative MEP results associated with postoperative events may occur in some patients. To achieve successful monitoring, collaboration between surgeon, anesthesiologist and an experienced technician is mandatory.