Postoperative Motor Deterioration Research Articles

Surgical outcomes in instrumented surgery for dumbbell type spinal cord tumor -the comparison with non-instrumented surgery for spinal cord tumor

BackgroundThere is little information on outcomes for spinal cord tumor treated surgically with instrumentation. Analysis of surgical outcomes and complications in such cases is needed to develop generalizable conclusions and to help inform patients. MethodsThe subjects were 41 patients treated with instrumentation surgery for dumbbell type tumor resection. Demographic data; tumor histology, level, and location; number of fused vertebra; use of a bilateral or hemilateral screw; operative time; EBL; TcMEP monitoring; lumbar subarachnoid drainage; duration of subfascial drainage; postoperative motor and sensory deficits; CSF leakage, implant-related complications; time for union of fused vertebra; salvage surgeries, and pre-/postoperative McCormick scale were obtained from medical records. Significant factors related to postoperative motor deficits were identified. ResultsPostoperative motor deficit occurred in 9 cases (22.0%) and all recovered in 30 days after surgery. CSF leakage at 7 days and 2 years after surgery was subfascial (n = 31, n = 6) and subcutaneous (n = 3, n = 4). Cases with postoperative motor deficits more commonly had lower cervical lesions; those with CSF leakage had longer operative times; and those with delayed union had more use of hemilateral instrumentation. ConclusionIn this study in 41 spinal cord tumors treated surgically with instrumentation, the rate of postoperative motor deterioration was 22.0%, and CSF leakage was found in 17.1%.

New cutoffs for intraoperative somatosensory and motor evoked potentials during brain surgery

We aimed to identify the most reliable cutoff points for changes in somatosensory (SEPs) and motor (MEPs) evoked potentials to predict postoperative motor deterioration after brain surgery. The data of 104 patients who had undergone brain surgery between December 2015 and December 2016 were reviewed. The muscle strength evaluated on the day before, within 48 h and 4 weeks after surgery were reviewed. The sensitivity and specificity of the existing alarm criteria of intraoperative SEP and MEP for postoperative motor deterioration were evaluated, and receiver operating characteristic (ROC) curve analysis was performed to identify the optimal cutoffs. The sensitivities of pre-existing SEPs and MEPs alarm criteria were 8.3% and 16.7%, with specificities of 96.7% and 95.7%, respectively. ROC curve analysis estimated discriminating points for latency change in SEPs and amplitude change in MEPs of 7.1% and 21.0%, respectively. With these cutoffs, the sensitivities of SEPs and MEPs were 66.7% and 91.7%, with specificities of 79.4% and 55.4%, respectively. For brain surgery, we suggest new alarm criteria with cutoff values of a 7.1% prolongation in SEP latency or a 21.0% reduction in MEP amplitude.

Intraoperative electromyographic techniques for the decision-making of tumor-involved nerve root resection for treating spinal schwannomas

BACKGROUND CONTEXTTotal removal of spinal schwannomas is ideal but it sometimes requires tumor-involved root resection, which increases the risk of postoperative motor deterioration (PMD). Therefore, it is important for clinicians to predict the impact of tumor-involved root resection on motor function in spinal schwannomas. PURPOSETo investigate the role of intraoperative electromyographic (EMG) techniques in decision-making of tumor-involved root resection for treating spinal schwannomas. STUDY DESIGNA retrospective analysis PATIENT SAMPLESixty-eight patients with spinal schwannomas arising from C5-T1 or L3-S1 roots underwent total resection of schwannoma, including tumoral root. OUTCOME MEASURESNerve root activation threshold, free-running EMG signals, visual analogue scale, and American Spinal Injury Association scale. METHODSDuring evoked EMG, nerve root activation threshold for tumoral root stimulation was recorded from muscles anatomically corresponding to tumoral root. During free-running EMG, abnormal EMG signals were identified as irregularly recurrent, monomorphic signals, low frequency (<5 Hz) or absent discharges recorded from muscles innervated by tumoral root. Clinical assessments were performed before, 3 to 5 day's and six months’ after operation. RESULTSSixteen (16 of 68, 23.5%) patients showed PMD, and muscle strength improved or was not affected in the other 52 patients. Absent myogenic responses were observed in 19 patients with non–PMD, and nerve root activation threshold in non–PMD group was higher than that in PMD group (p<.05). Receiver operating characteristic curve revealed that cut-off value of nerve root activation threshold for distinguishing functional and nonfunctional roots was 11.8 mA. A larger number of patients without PMD than with PMD showed abnormal free-running EMG signals (p<.05). At postoperative 6-months’ follow-up, ten patients with muscle weakness after tumor-involved root resection showed functional recovery (full vs. partial recovery: 5 vs. 5), and intraoperative nerve root activation threshold in these patients was higher than that in the other patients without functional recovery (p<.05). Furthermore, there is negative relationship between the duration for full recovery and nerve root activation threshold (p<.05). CONCLUSIONSBoth evoked and free-running EMG can be used as supplementary tests for differentiating functional and nonfunctional tumoral roots in spinal schwannomas, and nerve root activation threshold may be also related to prognosis of patients with muscle weakness caused by tumor-involved root resection. Therefore, intraoperative EMG techniques may provide additional references in decision-making of tumor-involved root resection.

Characteristics of Tc-MEP Waveforms in Spine Surgery for Patients with Severe Obesity.

Prospective multicenter study. The aim of this study was to evaluate transcranial motor evoked potential (Tc-MEP) waveform monitoring in spinal surgery for patients with severe obesity. Spine surgeries in obese patients are associated with increased morbidity and mortality. Intraoperative Tc-MEP monitoring can identify neurologic deterioration during surgery, but has not been examined for obese patients. The subjects were 3560 patients who underwent Tc-MEP monitoring during spine surgery at 16 centers. Tc-MEPs were recorded from multiple muscles via needle or disc electrodes. A decrease in Tc-MEP amplitude of ≥70% from baseline was used as an alarm during surgery. Preoperative muscle weakness with manual muscle test (MMT) grade ≤4 was defined as a motor deficit, and a reduction of one or more MMT grade postoperatively was defined as deterioration. The 3560 patients (1698 males, 47.7%) had a mean age of 60.0 ± 20.3 years. Patients with body mass index >35 kg/m2 (n = 60, 1.7%) were defined as severely obese. Compared with all other patients (controls), the rates of preoperative motor deficit (41.0% vs. 29.6%, P < 0.05) and undetectable baseline waveforms in all muscles were significantly higher in the severely obese group (20.0% vs. 1.7%, P < 0.01). Postoperative motor deterioration did not differ significantly between the groups. The sensitivity and specificity of the alarm criterion for prediction of postoperative neurologic complications were 75.0% and 83.9% in severely obese patients and 76.4% and 89.6% in controls, with no significant difference between the groups. Tc-MEPs can be used in spine surgery for severely obese cases to predict postoperative motor deficits, but the rate of undetectable waveforms is significantly higher in such cases. Use of a multichannel waveform approach or multiple modalities may facilitate safe completion of surgery. Waveforms should be carefully evaluated and an appropriate rescue procedure is required if the alarm criterion occurs.Level of Evidence: 3.

The Seven-Color TcMsEP Grading System: A Novel Alarm Method for Intraoperative Neurophysiological Monitoring Using Transcranial Electrical Stimulated Muscle Evoked Potentials (TcMsEPs) in Intramedullary Spinal Cord Tumor Surgeries.

Introduction Surgeons need precise information about motor deterioration risk during surgery for intramedullary spinal cord tumors (IMSCTs). However, the conventional TcMsEP alarm criterion provides limited information with a less than or a more than single alarm criterion without any grades in between, resulting in false-negative and false-positive outcomes. Therefore, we developed a “seven-color TcMsEP grading system” for neuromonitoring to provide more graded information. This study investigates the system's efficacy. Methods This study included 60 patients that underwent resection surgeries for IMSCTs. TcMsEP outcomes were classified into seven grades: Grade “D-0 Green” includes a wave amplitude decrease of 0%-50% compared with the baseline amplitude. Grade “D-1 Lime” includes a 50%-70% decrease. Grade “D-2 Yellow” includes a 70%-90% decrease. Grade “D-3 Orange” includes a more than 90% decrease with a clearly visible waveform. Grade “D-4 Red” includes a minimal and abnormally shaped wave. The severest, grade “D-5 Black,” includes a wave that has completely disappeared. The additional grade “D-X Gray” includes cases in which the baseline wave is undetectable. Postoperative motor deterioration was evaluated in the upper limbs (PUMD) and lower limbs (PLMD) individually. Results PLMD only occurred in cases with more than a 90% wave amplitude decrease (from D-3 to D-5) and with the undetectable baseline wave (D-X). The PLMD rate increased according to the severity of the amplitude decreases (29% in D-3, 67% in D-4, 80% in D-5). Most PUMD occurred in cases with more than a 90% decrease, but one case with grade D1 had PUMD.Conclusions The seven-color graded alarm criterion supports surgeons' decisions on how to treat the wave amplitude decrease during surgery. It provides motor deterioration risk in each grade without false negatives. Moreover, the corresponding colors enable quick comprehension of the risks.

Correlation between preoperative somatosensory evoked potentials and intraoperative neurophysiological monitoring in spinal cord tumors.

Intraoperative neurophysiological monitoring (IONM) is widely used in spinal cord tumors (SCTs) removal surgery. This study mainly hypothesized that patients with prolonged latency of preoperative somatosensory evoked potentials (preSEPLat) would have more deteriorated intraoperative evoked potentials. Among 506 patients who underwent SCTs removal surgery, 74 underwent both preSEPs and IONM. The correlation between preSEPLat and intraoperative SEPs (ioSEPs) was mainly analyzed, and subgroup analysis according to anatomical type was also conducted. Secondly, whether preSEPLat related to intraoperative motor evoked potentials (ioMEPs) or postoperative motor deterioration (PMD) was analyzed. In addition, risk factors for PMD were examined among anatomical factors, including operation level, tumor-occupying area ratio, and anatomical type, as well as electrophysiological factors, such as preSEPLat, ioSEPs, and ioMEPs. Changes in ioSEP and ioMEP were considered significant even if they were recovered before the end of the monitoring. Patients with prolonged preSEPLat were more likely to have significant ioSEP changes for intradural-extramedullary (IDEM) but not for intramedullary or extradural tumors. The anatomical type and tumor-occupying area ratio were prognostic factors for transient PMD, while the ioSEPs were the only prognostic factor for persisted PMD over 4weeks after surgery. PreSEPs are helpful in predicting the significant changes in ioSEPs during IDEM tumor removal surgery. The tumor-occupying area ratio and anatomical type are contributing factors for the transient PMD, whereas ioSEPs are prognostic factors in predicting the PMD that persists over 4weeks after SCTs removal surgery. To our knowledge, this is the first study that mainly focused on the correlations of preoperative and intraoperative evoked potentials.

Neurological Disturbance of the Upper Extremities After Cervical Laminoplasty: A Morphological Assessment Focused on the Intervertebral Foramen.

A retrospective study. The aim of this study was to explore the relationship between postoperative neurological disturbance of the upper extremities (NDUE) after cervical laminoplasty and intervertebral foraminal stenosis. The relationship between foraminal stenosis and neurological disturbance in the C5 segment (C5 palsy) has been reported, but the relationship at other levels has not been examined before. We evaluated foraminal stenosis morphologically using three-dimensional computed tomography (3D-CT), alongside other risk factors for NDUE. We retrospectively reviewed patients treated by open-door laminoplasty at the authors' institution between January and June 2016. NDUE was defined as postoperative motor deterioration and/or newly emerged sensory disturbance within 2 weeks of surgery. Radiological measurements were performed in bilateral intervertebral foramina from C5 to C8, using 3D-CT. Investigation using magnetic resonance imaging (MRI) was also performed. Thirty-one patients were reviewed, and 10 (32.3%) developed NDUE. Nineteen NDUE were observed: seven were in the C5 segment, five in the C6 segment, three in the C7 segment, and four in the C8 segment. Four patients (40%) had NDUE from multiple segments. The mean width of the foramen was 2.60 ± 1.26 mm and 3.66 ± 1.66 mm (P = 0.007), and cross-sectional area was 32.8 ± 10.8 mm and 41.6 ± 12.4 mm (P = 0.003), in symptomatic (n = 19) and nonsymptomatic (n = 187) foramina, respectively. The mean transverse diameter of bony spurs and the maximum shift of the spinal cord on MRI was significantly larger in the NDUE group. The odds ratio of having a foraminal cross-sectional area under 28.0 mm in combination with a maximum spinal shift over 3.10 mm was 14.6 (P < 0.001). Stenosis of the intervertebral foramen could be a risk factor for NDUE after cervical laminoplasty, and could be aggravated by excessive posterior spinal cord shift. 3.

Anatomic Understanding of Subtotal Hemispherotomy Using Cadaveric Brain, 3-Dimensional Simulation Models, and Intraoperative Photographs.

When the epileptogenic foci skip the motor area, the epilepsy can be cured by surgery while preserving the motor function. This surgery has been reported as subtotal hemispherectomy. The disconnective variant of this surgery, subtotal hemispherotomy, is described. To demonstrate each step clearly, a cadaveric brain, 3-dimensional reconstruction and simulation model, and intraoperative photographs were used. A formalin-fixed cadaveric brain was dissected to show each step of this surgery. For the 3-dimensional model, several brain structures were reconstructed from preoperative images, and the surgery was simulated. Intraoperative photographs and postoperative magnetic resonance images were taken from the representative cases. Temporo-parieto-occipital disconnection is performed to disconnect these lobes and the insula, limbic system, and splenium of the corpus callosum. The postcentral sulcus is the anterior border of the disconnection. Next, prefrontal disconnection is performed to disconnect the frontal lobe and the insula, frontal lobe and basal ganglia, and the anterior part of the corpus callosum. The precentral sulcus is the posterior border of the disconnection. Finally, corpus callosotomy of the central part is performed. After these steps, subtotal hemispherotomy, with preservation of the pre- and postcentral gyrus, is achieved. The 3-dimensional model clearly shows the anatomic relationships between deep brain structures. In the representative cases, postoperative motor deterioration was transient or none, and seizure-free status was achieved after surgery. Subtotal hemispherotomy is generally difficult because of the complicated anatomy and narrow and deep surgical corridors. Combined use of these methods facilitates a clearer understanding of this surgery.

NTMS mapping of non-primary motor areas in brain tumour patients and healthy volunteers.

Navigated transcranial magnetic stimulation (nTMS) has been increasingly used for presurgical cortical mapping of the primary motor cortex (M1) but remains controversial for the evaluation of non-primary motor areas (NPMA). This study investigates clinical and neurophysiological parameters in brain tumour patients and healthy volunteers to decide whether single-pulse biphasic nTMS allows to reliably elicite MEP outside from M1 or not. Twelve brain tumour patients and six healthy volunteers underwent M1 nTMS mapping. NPMA nTMS mapping followed using 120% and 150% M1 resting motor threshold (RMT) stimulation intensity. Spearman's correlation analysis tested the association of clinical and neurophysiological parameters between M1 and NPMA mapping. A total of 88.81% of nTMS stimulations in NPMA in patients/83.87% in healthy volunteers in patients/83.87% in healthy volunteers did not result in MEPs ≥ 50μV. Positive nTMS mapping in NPMA correlated with higher stimulation intensity and larger M1 areas in patients (120% M1 RMT SI p = 0.005/150% M1 RMT SI p = 0.198). Our findings indicate that in case of positive nTMS mapping in NPMA, MEPs originate mostly from M1. For future studies, MEP parameters and TMS coil rotation should be studied closely to assess the risk for postoperative motor deterioration.

Intraoperative Neurophysiological Monitoring for Spinal Cord Tumor Surgery: Comparison of Motor and Somatosensory Evoked Potentials According to Tumor Types.

ObjectiveTo identify which combination of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) is most reliable for postoperative motor deterioration during spinal cord tumor surgery, according to anatomical and pathologic type.MethodsMEPs and SEPs were monitored in patients who underwent spinal cord tumor surgery between November 2012 and August 2016. Muscle strength was examined in all patients before surgery, within 48 hours postoperatively and 4 weeks later. We analyzed sensitivity, specificity, positive and negative predictive values of each significant change in SEPs and MEPs.ResultsThe overall sensitivity and specificity of SEPs or MEPs were 100% and 61.3%, respectively. The intraoperative MEP monitoring alone showed both higher sensitivity (67.9%) and specificity (83.2%) than SEP monitoring alone for postoperative motor deterioration. Two patients with persistent motor deterioration had significant changes only in SEPs. There are no significant differences in reliabilities between anatomical types, except with hemangioma, where SEPs were more specific than MEPs for postoperative motor deterioration. Both overall positive and negative predictive values of MEPs were higher than the predictive values of SEPs. However, the positive predictive value was higher by the dual monitoring of MEPs and SEPs, compared to MEPs alone.ConclusionFor spinal cord tumor surgery, combined MEP and SEP monitoring showed the highest sensitivity for the postoperative motor deterioration. Although MEPs are more specific than SEPs in most types of spinal cord tumor surgery, SEPs should still be monitored, especially in hemangioma surgery.

Treatment outcomes of surgical clipping for unruptured anterior circulation aneurysm-single institute experiences in the era of neurophysiologic monitoring and endovascular treatment.

Recently, the treatment of intracranial aneurysms entered a new phase due to safe surgical tool such as neurophysiologic monitoring and challenged by endovascular treatment. To determine the safety of clipping surgery in the modern era, we reviewed our experiences of simple unruptured anterior circulation aneurysm surgery which is commonly performed in many places. We retrospectively reviewed 610 consecutive patients who were treated with surgical clipping under motor evoked potential (MEP) monitoring for a tiny to large anterior circulation aneurysm in a single institute between 2008 and 2012. MEP changes were identified in 40 cases (6.6%). MEP deterioration was associated with remote site epidural hematoma (n = 1), anesthesia (n = 2), temporary clipping (n = 21), and permanent clipping (n = 16). Despite that no persistent MEP deterioration was noted after prompt corrective measures, 56 (9.2%) patients showed symptomatic (n = 14) and asymptomatic (n = 42) radiologic abnormalities. Anterior cerebral artery (ACA) aneurysm was associated with a higher radiologic complication rate (Fisher's exact test, P < 0.05). Two (0.3%) patients showed severe morbidity (mRS >2) at latest follow-up. MEP monitoring can be helpful in preventing postoperative motor deterioration but seems to have some limitations. Although the permanent morbidity rate was low, a significant clinical (2.3%) or radiologic (9.2%) abnormality rate was identified even in simple aneurysm clipping that should be taken into account when performing interdisciplinary treatment planning and patient counseling. Also, direct vascular monitoring or new neurophysiologic monitoring techniques are needed to reduce surgical complications, especially in ACA aneurysm surgery.

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.

Intraoperative Seizures During Awake Craniotomy

Awake craniotomy (AC) for removal of intra-axial brain tumors is a well-established procedure. However, the occurrence and consequences of intraoperative seizures during AC have not been well characterized. To analyze the incidence, risk factors, and consequences of seizures during AC. The database of AC at Tel Aviv Medical Center between 2003 to 2011 was reviewed. Occurrences of intraoperative seizures were analyzed with respect to medical history, medications, tumor characteristics, and postoperative outcome. Of the 549 ACs performed during the index period, 477 with complete records were identified. Sixty patients (12.6%) experienced intraoperative seizures. The AC procedure failed in 11 patients (2.3%) due to seizures. Patients with intraoperative seizures were significantly younger than nonseizing patients (45 ± 14 years vs 52 ± 16 years, P = .003), had a higher incidence of frontal lobe involvement (86% vs % 57%, P < .0001), and had higher prevalence of a history of seizures (P = .008). Short-term motor deterioration developed postoperatively in a higher percentage of patients with intraoperative seizures (20% vs 10.1%, P = .02) with a longer hospitalization period (4.0 ± 3.0 days vs 3.0 ± 3.0 days, P = .045). Although in most cases intraoperative seizures will not result in AC failure, the surgical team should be prepared to treat them promptly to avoid intractable seizures. Intraoperative seizures are more common in younger patients with a tumor in the frontal lobe and those with a history of seizures. Moreover, they are associated with a higher incidence of transient postoperative motor deterioration and protracted length of hospital stay.

The Use of Diffusion Tensor Images of the Corticospinal Tract in Intrinsic Brain Tumor Surgery

Diffusion tensor imaging (DTI) is now widely used in neurosurgery to preoperatively delineate the course of the pyramidal tract. To evaluate the accuracy of the method by comparison with subcortical electrical stimulation and to evaluate the influence of the distance of the pyramidal tract from the tumor on the resection extent and postoperative clinical deficits. A diffusion tensor imaging depiction of the pyramidal tract was used in preoperative planning and intraoperative navigation in 72 cases. In 36 cases, subcortical electrical stimulation was used during the resection. The preoperative tumor-to-tract distance was compared with the stimulation result, the extent of resection, and the short-term postoperative course. A significant nonlinear relationship between the tract-to-tumor distance and the probability of a motor response to subcortical stimulation was observed. The largest preoperatively measured tumor-to-tract distance with a positive stimulation result was 8 mm. Moreover, we observed a trend toward transient postoperative motor deterioration in patients with tumors close to the pyramidal tract. Resection extent was not significantly affected by the tumor-to-tract distance. Despite methodological obstacles, reasonable accuracy of the diffusion tensor imaging reconstructions of the pyramidal tracts was confirmed by our study. The occurrence of transient postoperative motor deterioration is higher in patients with tumors located close to the pyramidal tract.

Feasibility of intraoperative motor-evoked potential monitoring for skull base tumors with a high risk of postoperative motor deterioration

To establish the validity and utility of motor-evoked potential (MEPs) monitoring for skull base tumor resection, we explored the relationship between MEP monitoring results and postoperative motor function. MEPs were successfully monitored during 76 operations in 68 patients with a high risk of motor morbidity. MEP monitoring data were correlated with perioperative clinical motor function. MEPs remained stable in 56 operations (73.7%), and no postoperative motor deterioration was observed. Transient or permanent deterioration of MEPs (<50% of the initial amplitude before surgery) occurred in 20 operations (26.3%). This deterioration was reversible after intervention in seven cases (9.2%). Irreversible deterioration in MEPs was seen in 13 cases (17.1%). In five cases, the final amplitude was greater than 10%. Two of these patients experienced transient loss of MEPs and moderate to severe hemiparesis. Both patients showed full recovery within 6months after the operation. The other three patients experienced no postoperative worsening of motor function. The final MEP amplitude was less than 10% in the other eight patients, including five with permanent MEP loss. All of these patients experienced severe postoperative motor dysfunction. Recovery of motor function was worse in most participants in this group compared with those in the other groups. Intraoperative MEP monitoring is a valid indicator of pyramidal tract pathway function for skull base tumor surgery.

Surgical treatment of high-grade gliomas in motor areas. The impact of different supportive technologies: a 171-patient series

In the last few years much has been published to validate new technology in brain mapping for clinical purposes, but there have been few clinical results. In this report we describe our five-year experience in the surgical management of malignant gliomas around motor areas with an evaluation of the impact of functional magnetic resonance imaging (fMRI) plus navigator and intraoperative neurophysiology (IN). End-points were extent of removal, morbidity, and survival. Variables describing patient and tumor characteristics and treatment modalities were statistically weighted in relation to treatment outcome. Tumor depth (P = 0.01), midline shift ≥1 cm. (P = 0.05), and insular location (P = 0.001) negatively affected extent of removal, whereas IN (P < 0.001) and fMRI plus navigator (P = 0.02) contributed to increasing the rate of total removal (73%, 71% vs. 40%). Postoperative motor impairment was mild and transient in a minority of cases (20%). General complications, as defined by the Glioma Outcome Project, occurred in 23% of cases. IN was the only factor associated with acute postoperative motor deterioration (P < 0.001). IN and age >65 years (P = 0.01) were associated with the occurrence of complications. Overall survival was significantly higher in patients operated with IN or fMRI plus navigator (P < 0.01). Comparing different surgical strategies used in the same period, we observed that supportive technologies in glioma surgery have their primary impact on the quality of resection and survival. IN led to transient motor impairment and some additional complications which did not affect functional outcome.

CLINICAL EVALUATION AND FOLLOW-UP OUTCOME OF DIFFUSION TENSOR IMAGING-BASED FUNCTIONAL NEURONAVIGATION

To evaluate diffusion tensor imaging (DTI)-based functional neuronavigation in surgery of cerebral gliomas with pyramidal tract (PT) involvement with respect to both perioperative assessment and follow-up outcome. A prospective, randomized controlled study was conducted between 2001 and 2005. A consecutive series of 238 eligible patients with initial imaging diagnosis of cerebral gliomas involving PTs were randomized into study (n = 118) and control (n = 120) groups. The study cases underwent DTI and three-dimensional magnetic resonance imaging scans. The maps of fractional anisotropy were calculated for PT mapping. Both three-dimensional magnetic resonance imaging data sets and fractional anisotropy maps were integrated by rigid registration, after which the tumor and adjacent PT were segmented and reconstructed for presurgical planning and intraoperative guidance. The control cases were operated on using routine neuronavigation. There was a trend for high-grade gliomas (HGGs) in the study group to be more likely to achieve gross total resection (74.4 versus 33.3%, P < 0.001). There was no significant difference of low-grade gliomas resection between the two groups. Postoperative motor deterioration occurred in 32.8% of control cases, whereas it occurred in only 15.3% of the study cases (P < 0.001). The 6-month Karnofsky Performance Scale score of study cases was significantly higher than that of control cases (86 +/- 20 versus 74 +/- 28 overall, P < 0.001; 93 +/- 10 versus 86 +/- 17 for low-grade gliomas, P = 0.013; and 77 +/- 27 versus 53 +/- 32 for HGGs, P = 0.001). For 81 HGGs, the median survival of study cases was 21.2 months (95% confidence interval, 14.1-28.3 mo) compared with 14.0 months (95% confidence interval, 10.2-17.8 mo) of control cases (P = 0.048). The estimated hazard ratio for the effect of DTI-based functional neuronavigation was 0.570, representing a 43.0% reduction in the risk of death. DTI-based functional neuronavigation contributes to maximal safe resection of cerebral gliomas with PT involvement, thereby decreasing postoperative motor deficits for both HGGs and low-grade gliomas while increasing high-quality survival for HGGs.