Trends and Long-term Health Care Utilization of Computer-assisted Neuronavigation in Spine Fusions: An Exact Matched Analysis of National Administrative Database.

BACKGROUND: Computer-assisted neuronavigation (CAN) during spine fusions has increasingly been utilized in the United States. The aim of this study was to analyze the trends, health care utilization, and clinical outcomes associated with CAN use. METHODS: The MarketScan database was queried using the ICD-9/10 and CPT 4th edition, from 2003 to 2019. We included patients aged ≥18 years with at least 2 years of follow-up. Outcomes were repeat/new fusions, length of stay (LOS), discharge disposition, hospital re-admissions, outpatient services, and medication refills for up to 24 months. RESULTS: Of 183,620 patients who underwent spine fusions, 5046 (2.75%) were identified to have CAN utilized. CAN is increasingly being utilized for spine fusions since 2010, reaching 10.76% of all fusions in 2017, compared to 0.38% in 2010. CAN had no impact on LOS, home discharge, or complications at index hospitalization and 30-days post discharge. CAN was associated with lower rates of repeat fusions at 6 months (1% vs. 2%) and 24 months (5% vs. 6%), P < 0.05. Patients who underwent CAN had lower payments at 6 months ($5186 vs. $5527, P = 0.0159), 12 months ($10,267 v.s $11,262, P = 0.0207), and 24 months ($21,453 vs. $24,355, P = 0.0021). CONCLUSIONS: CAN is increasing being used for spine fusions primarily for thoracolumbar procedures. No difference in complications, discharge disposition, and LOS were noted across the cohorts at index hospitalization, with higher index payments with CAN use. CAN was associated with lower rates of repeat fusions and corresponding health care utilization for up to 24 months.

Awake craniotomy for removal of gliomas in eloquent areas: An analysis of 21 cases.

OBJECTIVE: To discuss the techniques and methods in respective operation of brain gliomas located in eloquent brain region under awake anesthesia state METHODS: 21 patients admitted into Department of Neurosurgery of the First Affiliated Hospital of Xiamen University were chosen as subject. Diagnosed with brain gliomas, they received operation with neuronavigation, intraoperative ultrasonography for locating the lesion and intraoperative direct electric stimulation for functional mapping of the eloquent brain region after receiving awake anesthesia. All patients were followed up from post-surgical 3 months to 18 months. RESULTS: Applied with MRI scanning during post-surgical 60-90d, resection results shows that 5 cases (23.8%) received total resection of lesions, 10 cases (47.6%) received subtotal resection while 6 cases (28.6%) received partial resection. Post-surgical performance shows 8 cases (38.1%) of transitory postoperative aphasia, 5 cases(23.8%) of transitory postoperative dyskinesia and 1 case(4.8%) of permanent dyskinesia. Recovery was achieved in the patients except for the 1 case of permanent dyskinesia. CONCLUSIONS: Comprehensive application of awake anesthesia, neuronavigation, intraoperative ultrasonography and intraoperative direct electrical stimulation facilitates recognition of clear position relationship between gliomas and eloquent brain region, and maximum safe resection of gliomas in eloquent brain region with maximal protection of brain function.

Safety assessment of intraparenchymal central nervous system biopsies: Single institution healthcare value review.

The study objective was to evaluate a single institution experience with adult stereotactic intracranial biopsies and review any projected cost savings as a result of bypassing intensive care unit (ICU) admission and limited routine head computed tomography (CT). The authors retrospectively reviewed all stereotactic intracranial biopsies performed at a single institution between February 2012 and March 2019. Primary data collection included ICU length of stay (LOS), hospital LOS, ICU interventions, need for reoperation, and CT use. Secondarily, location of lesion, postoperative hematoma, neurological deficit, pathology, and preoperative coagulopathy data were collected. There were 97 biopsy cases (63% male). Average age, ICU LOS, and total hospital stay were 58.9 years (range; 21-92 years), 2.3 days (range; 0-40 days), and 8.8 days (range 1-115 days), respectively. Seventy-five (75 of 97) patients received a postoperative head CT. No patients required medical or surgical intervention for complications related to biopsy. Eight patients required transfer from the ward to the ICU (none directly related to biopsy). Nine patients transferred directly to the ward postoperatively (none required transfer to ICU). Of the patients who did not receive CT or went directly to the ward, none had extended LOS or required transfer to ICU for neurosurgical concerns. Eliminating routine head CT and ICU admission translates to approximately $584,971 in direct cost savings in 89 cases without a postoperative ICU requirement. These practice changes would save patients' significant hospitalization costs, decrease healthcare expenditures, and allow for more appropriate hospital resource use.

Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks.

INTRODUCTION: The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient's head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery. MATERIAL AND METHODS: Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients' head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications. RESULTS: Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system. CONCLUSIONS: This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

VarioGuide® frameless neuronavigation-guided stereoelectroencephalography in adult epilepsy patients: technique, accuracy and clinical experience.

BACKGROUND: Stereoelectroencephalography (SEEG) allows the identification of deep-seated seizure foci and determination of the epileptogenic zone (EZ) in drug-resistant epilepsy (DRE) patients. We evaluated the accuracy and treatment-associated morbidity of frameless VarioGuide® (VG) neuronavigation-guided depth electrode (DE) implantations. METHODS: We retrospectively identified all consecutive adult DRE patients, who underwent VG-neuronavigation DE implantations, between March 2013 and April 2019. Clinical data were extracted from the electronic patient charts. An interdisciplinary team agreed upon all treatment decisions. We performed trajectory planning with iPlan® Cranial software and DE implantations with the VG system. Each electrode's accuracy was assessed at the entry (EP), the centre (CP) and the target point (TP). We conducted correlation analyses to identify factors associated with accuracy. RESULTS: The study population comprised 17 patients (10 women) with a median age of 32.0 years (range 21.0-54.0). In total, 220 DEs (median length 49.3 mm, range 25.1-93.8) were implanted in 21 SEEG procedures (range 3-16 DEs/surgery). Adequate signals for postoperative SEEG were detected for all but one implanted DEs (99.5%); in 15/17 (88.2%) patients, the EZ was identified and 8/17 (47.1%) eventually underwent focus resection. The mean deviations were 3.2 ± 2.4 mm for EP, 3.0 ± 2.2 mm for CP and 2.7 ± 2.0 mm for TP. One patient suffered from postoperative SEEG-associated morbidity (i.e. conservatively treated delayed bacterial meningitis). No mortality or new neurological deficits were recorded. CONCLUSIONS: The accuracy of VG-SEEG proved sufficient to identify EZ in DRE patients and associated with a good risk-profile. It is a viable and safe alternative to frame-based or robotic systems.

The impact of age on approach-related complications with navigated lateral lumbar interbody fusion.

OBJECTIVE: Age is known to be a risk factor for increased complications due to surgery. However, elderly patients can gain significant quality-of-life benefits from surgery. Lateral lumbar interbody fusion (LLIF) is a minimally invasive procedure that is commonly used to treat degenerative spine disease. Recently, 3D navigation has been applied to LLIF. The purpose of this study was to determine whether there is an increased complication risk in the elderly with navigated LLIF. METHODS: Patients who underwent 3D-navigated LLIF for degenerative disease from 2014 to 2019 were included in the analysis. Patients were divided into elderly and nonelderly groups, with those 65 years and older categorized as elderly. Ninety-day medical and surgical complications were recorded. Patient and surgical characteristics were compared between groups, and multivariate regression analysis was used to determine independent risk factors for complication. RESULTS: Of the 115 patients included, 56 were elderly and 59 were nonelderly. There were 15 complications (25.4%) in the nonelderly group and 10 (17.9%) in the elderly group, which was not significantly different (p = 0.44). On multivariable analysis, age was not a risk factor for complication (p = 0.52). However, multiple-level LLIF was associated with an increased risk of approach-related complication (OR 3.58, p = 0.02). CONCLUSIONS: Elderly patients do not appear to experience higher rates of approach-related complications compared with nonelderly patients undergoing 3D navigated LLIF. Rather, multilevel surgery is a predictor for approach-related complication.

Surgical Results of Brainstem Cavernous Malformation Haemorrhage.

AIM: To evaluate surgical treatment options, complications and neurological outcomes of patients with cavernous malformations (CMs) in the pons and medulla oblongata. MATERIAL AND METHODS: We retrospectively evaluated 25 brain stem CMs that we operated between 2009 and 2019. We operated all cases in the first month with suboccipital retrosigmoid and paramedian approach. The cases were evaluated concerning their demographic characteristics, lesion characteristics, radiological imaging results, surgical approach and neurological status. RESULTS: Overall, 15 patients had CMs in the pons and 10 in the medulla oblongata. The mean age of the patients was 33.48 years, and the cases included 15 male and 10 female patients. The average modified Rankin Score (mRS) score had a mean of 2.36 and median of 2 at the time of admission (Table I). The mean follow-up period was 4.64 years (1?10 years). In the last follow-up assessment, the average mRS score was mean = 1.84 and median = 1. In addition, 14 (56%) patients recovered, 7 (28%) did not show any changes, 3 (12%) got worse, and 1 (4%) died. In our case series, the admission complaints were cranial nerve paralysis (24%) in 6 cases, nausea and vomiting in 1 (4%) and hemiparesis in 17 (68%). CONCLUSION: Experience, correct surgical approach and good knowledge of neuroanatomy are important in brainstem CM haemorrhages. Imaging methods, neuronavigation and neuromonitoring use are essential for patients undergoing surgery. In the presence of all these factors, the prognosis of patients will be better.

Are There Differences in Accuracy or Outcomes Scores Among Navigated, Robotic, Patient-specific Instruments or Standard Cutting Guides in TKA? A Network Meta-analysis.

BACKGROUND: Several kinds of cutting guides, including patient-specific instrumentation, navigation, standard cutting guides, accelerometer-based navigation, and robotic guidance, are available to restore a planned alignment during TKA. No previous study has simultaneously compared all of these devices; a network meta-analysis is an especially appealing method because it allows comparisons across approaches that were not compared head-to-head in individual randomized controlled trials. QUESTIONS/PURPOSES: We performed a network meta-analysis to determine whether novel approaches to achieving implant alignment, such as patient-specific instrumentation, navigation, accelerometer-based navigation, and robotic guidance, provide any advantage over standard cutting guides in terms of: (1) hip-knee-ankle (HKA) alignment outliers greater than ± 3°, (2) outcome scores (1989 - Knee Society Score and WOMAC score) measured 6 months after surgery, or (3) femoral and tibial implant malalignment (greater than ± 3°), taken separately, in the frontal and sagittal plane, as well as other secondary outcomes including validated outcome scores 1 and 2 years after surgery. METHODS: In our network meta-analysis, we included randomized controlled trials comparing the different cutting guides by using at least one of the previously specified criteria, without limitation on language or date of publication. We searched electronic databases, major orthopaedic journals, proceedings of major orthopaedic meetings, ClinicalTrials.gov, and the World Health Organization's International Clinical Trials Registry Platform until October 1, 2018. This led to the inclusion of 90 randomized controlled trials involving 9389 patients (mean age 68.8 years) with 10,336 TKAs. Two reviewers independently selected trials and extracted data. The primary outcomes were the proportion patients with malalignment of the HKA angle (defined as HKA > 3° from neutral) and the Knee Society Score and WOMAC scores at 6 months postoperatively. We combined direct and indirect comparisons using a Bayesian network meta-analysis framework to assess and compare the effect of different cutting guides on outcomes. Bayesian estimates are based on the posterior distribution of an endpoint and are called credible intervals. Usually the 95% credible interval, corresponding to a posterior probability of 0.95 that the endpoint lies in the interval, is computed. Unlike the frequentist approach, the Bayesian approach does not allow the calculation of the p value. RESULTS: The proportion of HKA outliers was lower with navigation than with patient-specific instrumentation (risk ratio 0.46 [95% credible interval (CI) 0.34 to 0.63]) and standard cutting guides (risk ratio 0.45 [95% CI 0.37 to 0.53]); however, this corresponded to an actual difference of only 12% of patients for navigation versus 21% of patients for patient-specific instrumentation, and 12% of patients for navigation versus 25% for standard cutting guides. We found no differences for other comparisons between different cutting guides, including robotics and the accelerometer. We found no differences in the Knee Society Score or WOMAC score between the different cutting guides at 6 months. Regarding secondary outcomes, navigation reduced the risk of frontal and sagittal malalignments for femoral and tibial components compared with the standard cutting guides, but none of the other cutting guides showed superiority for the other secondary outcomes. CONCLUSIONS: Navigation resulted in approximately 10% fewer patients having HKA outliers of more than 3°, without any corresponding improvement in validated outcomes scores. It is unknown whether this incremental reduction in the proportion of patients who have alignment outside a window that itself has been called into question will justify the increased costs and surgical time associated with the approach. We believe that until or unless these new approaches either (1) convincingly demonstrate superior survivorship, or (2) convincingly demonstrate superior outcomes, surgeons and hospitals should not use these approaches since they add cost, have a learning curve (during which some patients may be harmed), and have the risks associated with uncertainty of novel surgical approaches. LEVEL OF EVIDENCE: Level I, therapeutic study.

Navigation assisted tubular resection of lumbar osteoid osteoma: how I do it.

BACKGROUND: Osteoid osteoma is a benign primary bony tumor involving the spinal posterior arches. Surgical treatment is reserved to patients with severe pain or not responding to nonsteroidal anti-inflammatory medications. We report a minimally invasive transmuscular resection of an L5 isthmic osteoid osteoma, assisted by intraoperative 3D-fluoroscopy-based navigation. METHODS: Navigation tracking reference is placed on the spinous process. A simil-scan with 3D-fluoroscopy is obtained to allow autoregistration for spinal navigation. Tubular transmuscular approach, directed to the ipsilateral isthmus and pedicle, is performed. Under navigation guidance, the lesion is identified and removed. CONCLUSION: This technique is a safe and effective minimally invasive alternative to conventional surgical treatment of lumbar osteoid osteoma.

Endoscopic endonasal and transorbital routes to the petrous apex: anatomic comparative study of two pathways.

BACKGROUND AND OBJECTIVE: Surgical approaches to the petrous apex region are extremely challenging; while subtemporal approaches and variations represent the milestone of the surgical modules to reach such deep anatomical target, in a constant effort to develop minimally invasive neurosurgical routes, the endoscopic endonasal approach (EEA) has been tested to get a viable corridor to the petroclival junction. Lately, another ventral endoscopic minimally invasive route, i.e., the superior eyelid endoscopic transorbital approach, has been proposed to access the most lateral aspect of the skull base, including the petrous apex region. Our anatomic study aims to compare and combine such two endoscopic minimally invasive pathways to get full access to the petrous apex. Three-dimensional reconstructions and quantitative and morphometric data have been provided. MATERIAL AND METHODS: Five human cadaveric heads (10 sides) were dissected. The lab rehearsals were run as follows: (i) preliminary pre-operative CT scans of each specimen, (ii) pre-dissection planning of the petrous apex removal and its quantification, (iii) petrous apex removal via endoscopic endonasal route, (iv) post-operative CT scans, (v) petrous apex removal via endoscopic transorbital route, and (v) final post-operative CT scan with quantitative analysis. Neuronavigation was used to guide all dissections. RESULTS: The two endoscopic minimally invasive pathways allowed a different visualization and perspective of the petrous apex, and its surrounding neurovascular structures. After both corridors were completed, a communication between the surgical pathways was highlighted, in a so-called connection area, surrounded by the following important neurovascular structures: anteriorly, the internal carotid artery and the Gasserian ganglion; laterally, the internal acoustic canal; superiorly, the abducens nerve, the trigeminal root, and the tentorium cerebelli; inferomedially, the remaining clivus and the inferior petrosal sinus; and posteriorly, the exposed area of the brainstem. Used in a combined fashion, such multiportal approach provided a total of 97% of petrous apex removal. In particular, the transorbital route achieved a mean of 48.3% removal in the most superolateral portion of the petrous apex, whereas the endonasal approach provided a mean of 48.7% bone removal in the most inferomedial part. The difference between the two approaches was found to be not statistically significant (p = 0.67). CONCLUSION: The multiportal combined endoscopic endonasal and transorbital approach to the petrous apex provides an overall bone removal volume of 97% off the petrous apex. In this paper, we highlighted that it was possible to uncover a common path between these two surgical pathways (endonasal and transorbital) in a so-called connection area. Potential indications of this multiportal approach may be lesions placed in or invading the petrous apex and petroclival regions that can be inadequately reached via transcranial paths or via an endonasal endoscopic route alone.

Superior accuracy and precision of SEEG electrode insertion with frame-based vs. frameless stereotaxy methods.

BACKGROUND: Stereotactic electroencephalography (SEEG) has largely become the preferred method for intracranial seizure localization in epileptic patients due to its low morbidity and minimally invasive approach. While robotic placement is gaining popularity, many centers continue to use manual frame-based and frameless methods for electrode insertion. However, it is unclear how these methods compare in regard to accuracy, precision, and safety. Here, we aim to compare frame-based insertion using a CRW frame (Integra®) and frameless insertion using the StealthStation™ S7 (Medtronic®) navigation system for common temporal SEEG targets. METHODS: We retrospectively examined electrode targets in SEEG patients that were implanted with either frame-based or frameless methods at a level 4 epilepsy center. We focused on two commonly used targets: amygdala and hippocampal head. Stealth station software was used to merge pre-operative MR with post-operative CT images for each patient, and coordinates for each electrode tip were calculated in relation to the midcommissural point. These were compared to predetermined ideal coordinates in regard to error and directional bias. RESULTS: A total of 81 SEEG electrodes were identified in 23 patients (40 amygdala and 41 hippocampal head). Eight of 45 electrodes (18%) placed with the frameless technique and 0 of 36 electrodes (0%) placed with the frame-based technique missed their target and were not clinically useful. The average Euclidean distance comparing actual to ideal electrode tip coordinates for frameless vs. frame-based techniques was 11.0 mm vs. 7.1 mm (p < 0.001) for the amygdala and 12.4 mm vs. 8.5 mm (p < 0.001) for the hippocampal head, respectively. There were no hemorrhages or clinical complications in either group. CONCLUSIONS: Based on this series, frame-based SEEG insertion is significantly more accurate and precise and results in more clinically useful electrode contacts, compared to frameless insertion using a navigation guidance system. This has important implications for centers not currently using robotic insertion.

A Review of Techniques, Time Demand, Radiation Exposure, and Outcomes of Skin-anchored Intraoperative 3D Navigation in Minimally Invasive Lumbar Spinal Surgery.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To describe our technique for and evaluate the time demand, radiation exposure and outcomes of skin-anchored intraoperative three-dimensional navigation (ION) in minimally invasive (MIS) lumbar surgery, and to compare these parameters to 2D fluoroscopy for MI-TLIF. SUMMARY OF BACKGROUND DATA: Limited visualization of anatomic landmarks and narrow access corridor in MIS procedures result in greater reliance on image guidance. Although two-dimensional fluoroscopy has historically been used, ION is gaining traction. METHODS: Patients who underwent MIS lumbar microdiscectomy, laminectomy, or MI-TLIF using skin-anchored ION and MI-TLIF by the same surgeon using 2D fluoroscopy were selected. Operative variables, radiation exposure, and short-term outcomes of all procedures were summarized. Time-demand and radiation exposure of fluoroscopy and ION for MI-TLIF were compared. RESULTS: Of the 326 patients included, 232 were in the ION cohort (92 microdiscectomies, 65 laminectomies, and 75 MI-TLIFs) and 94 in the MI-TLIF using 2D fluoroscopy cohort. Time for ION setup and image acquisition was a median of 22 to 24 minutes. Total fluoroscopy time was a median of 10 seconds for microdiscectomy, 9 for laminectomy, and 26 for MI-TLIF. Radiation dose was a median of 15.2 mGy for microdiscectomy, 16.6 for laminectomy, and 44.6 for MI-TLIF, of this, 93%, 95%, and 37% for microdiscectomy, laminectomy, and MI-TLIF, respectively were for ION image acquisition, with the rest attributable to the procedure. There were no wrong-level surgeries. Compared with fluoroscopy, ION for MI-TLIF resulted in lower operative times (92 vs. 108 min, P < 0.0001), fluoroscopy time (26 vs. 144 s, P < 0.0001), and radiation dose (44.6 vs. 63.1 mGy, P = 0.002), with equivalent time-demand and length of stay. ION lowered the radiation dose by 29% for patients and 55% for operating room personnel. CONCLUSION: Skin-anchored ION does not increase time-demand compared with fluoroscopy, is feasible, safe and accurate, and results in low radiation exposure. LEVEL OF EVIDENCE: 3.

Neuronavigation-Guided rTMS for the Treatment of Depressive Patients With Suicidal Ideation: A Double-Blind, Randomized, Sham-Controlled Trial.

During the last decade, the problem of suicide has become more serious in individuals with depression. Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for major depressive disorder (MDD). This study aims to investigate the efficacy of magnetic resonance imaging (MRI)-based neuronavigation-guided daily high-dose rTMS for rapidly improving suicidal ideation in treatment-naive patients with MDD. In the present 1-week double-blind study, 42 treatment-naive patients with MDD with suicidal ideation were randomly assigned to the treatment of escitalopram oxalate tablets (10 mg/d) in combination with either active (n = 21) or sham (n = 21) rTMS. The TMS coil was positioned over a specified target location (-44, 40, and 29) in left dorsolateral prefrontal cortex based on MRI data. The severity of suicidal ideation was measured by the Beck Scale for Suicide Ideation (BSI). The 24-item Hamilton Depression Rating Scale (HAMD-24) and Montgomery-Åsberg Depression Rating Scale (MADRS) were utilized to assess the severity of depression. The Wisconsin Card Sorting Test, Continuous Performance Test, and Stroop Color-Word Test were adopted to assess executive function. In contrast to the sham group, the active rTMS group showed a significantly greater BSI score reduction at the third day and the seventh day (P < 0.001). Moreover, the active rTMS group showed a significantly greater HAMD (P < 0.001) and MADRS (P < 0.001) score reduction at the seventh day in comparison to the sham group. The present findings suggested that the neuronavigation-guided high-dose rTMS may be a novel method to rapidly reduce suicidal ideation and mitigate depressive symptoms.

Single-Surgeon Direct Comparison of O-arm Neuronavigation versus Mazor X Robotic-Guided Posterior Spinal Instrumentation.

OBJECTIVE: We sought to compare intraoperative surgical instrumentation techniques with image-guidance versus robotic-guided procedures for posterior spinal fusion. METHODS: A retrospective review of institutional data collected from a single surgeon was used to compare surgical outcomes between O-arm neuronavigation and the Mazor X robotic-assistance system for placement of posterior spinal instrumentation in a consecutive series of patients. Univariate statistical significance testing compared time spent in the operating room, blood loss, screw accuracy, and wound healing. RESULTS: Between January 2017 and February 2019, 46 O-arm cases (mean age 59.6 years ± 13.7 years) and 39 Mazor X cases (mean age 59.5 years ± 12.4 years) were conducted. Cases were classified as degenerative, infectious, oncologic, and trauma with a mean of 4.57 and 5.43 levels operated on using O-arm neuronavigation and Mazor X, respectively. Mean operative times (P = 0.124), estimated blood loss (P = 0.212), wound revision rates (P = 0.560), and clinically acceptable instrumentation placement (P = 0.076) did not demonstrate significance between the 2 groups. However, screw placement was significantly more accurate and precise (P = 1 × 10-9) with robotic assistance when considering Gertzbein-Robbins A placement. CONCLUSIONS: Although a trend toward greater accuracy was noticed with robotic technology when determining clinically acceptable screws, there was not a significant difference when compared with O-arm neuronavigation. However, robotic technology has a significant effect on both precision and accuracy in Gertzbein-Robbins A screw placement. Robotics does not have a clear advantage when discussing infection rates, intraoperative blood loss, or operative time.

How I do it? Interlaminar contralateral endoscopic lumbar foraminotomy assisted with the O-arm navigation.

BACKGROUND: The interlaminar contralateral endoscopic lumbar foraminotomy (ICELF) provides access to the foraminal pathology with less violation to facet than the ipsilateral approach. However, it is technically challenging even for an experienced surgeon. METHODS: We introduce the step-by-step workflow of the interlaminar contralateral endoscopic lumbar foraminotomy assisted with O-arm navigation system. CONCLUSION: The ICELF assisted with O-arm navigation is safe, accurate, and efficient for the treatment of lumbar foraminal stenosis. The CT-based navigation reshapes the learning curve of the advanced endoscopic technique, reducing the risk of facet joint violation, and minimizes radiation exposure to surgeons.

How I do it? Lumbar cortical bone trajectory fixation with image-guided neuronavigation.

BACKGROUND: Cortical bone trajectory was described in 2009 to reduce screw loosening in osteoporotic patients. Since then, it has demonstrated improvements in biomechanical and perioperative results compared to pedicle screws, and it have been described as a minimally invasive technique. METHOD: We describe our experience with the technique assisted by 3D neuronavigation and review some of the complications and tools to avoid them together with limitations and pitfalls. CONCLUSION: Cortical bone trajectory guided by 3D neuronavigation helps to reduce the need for radiation and incidence of complications.

Ultrasound-based real-time neuronavigated fluorescence-guided surgery for high-grade gliomas: technical note and preliminary experience.

BACKGROUND: The extent of resection (EOR) plays a fundamental role in the prognosis of patients with high-grade gliomas (HGG). One of the main challenges in achieving a complete resection is the distinction between tumor and normal brain. Nowadays, several technologies are employed to obtain a higher tumor removal rate and respect the normal tissue in glioma surgery and in the last decades, fluorescein sodium (FS) and intraoperative ultrasound (IOUS) have been widely used. The aim of our technical note is to demonstrate how combining these two tools offers an ultrasound-based real-time neuronavigated fluorescence-guided surgery in order to optimize HGG removal. METHODS: Five patients (3 males, 2 females; mean age 55.2 years, range 36-68 years) undergoing craniotomies for removal of intraaxial lesions suggestive of high-grade gliomas on preoperative MRI were included in the study. Intraoperative navigated B-mode and CEUS associated with sodium fluorescein were used in all cases; white light appearance, IOUS, and fluorescence findings were recorded immediately after each surgery. Also, extent of resection was evaluated on postoperative Gd-enhanced MRI performed within 72 h. RESULTS: All tumors effectively stained yellow with fluorescein sodium during the surgical procedure and four were well delineated by IOUS. IOUS was repeated frequently (average 2.6 time) to obtain an orientation of the gross residual tumor with respect to anatomical landmarks as the surgery proceeded. Tumor removal was completed under Yellow 560 filter. CONCLUSIONS: In our technical report, we demonstrate that combining intraoperatively fluorescein sodium and IOUS improves the information and facilitates making decisions during the HGG surgery. Further experience gained in larger studies will help confirm these findings.

Safety and accuracy of frameless electromagnetic-navigated (AXIEMTM)-guided brain lesion biopsies: a large single-unit study.

BACKGROUND: Brain biopsies are required to establish a definitive histological diagnosis for brain lesions that have been identified on imaging in order to guide further treatment for patients. OBJECTIVE: Various navigation systems are in use but little up to date evidence is available regarding the safety and accuracy of a frameless, electromagnetic technique to target brain lesions. METHODS: Data was collected retrospectively on all patients that had brain biopsies at our institution from 01/01/2010 to 31/12/2017. Operation notes, neuropathology reports, and clinical notes on electronic patient record were used to determine whether biopsy of adequate identifiable abnormal tissue was achieved, whether a definitive diagnosis was established, any adverse events occurred, and if a repeat biopsy was carried out. RESULTS: Three hundred seventy-one AxiEM (Medtronic, Minneapolis, USA)-guided brain tumor biopsies were performed in this 8-year period. Three hundred forty-nine (94.07%) procedures provided definitive tissue diagnosis, 22 (5.93%) were non diagnostic; in 6 cases (1.62%), repeat biopsy was performed and adverse events which caused clinical compromise were observed in 4 patients (1.08%). CONCLUSIONS: The AxiEM is a fast, effective, and safe frameless and pinless neuronavigational system. It offers a high degree of accuracy required for the establishment of a definitive diagnosis, permitting optimal further treatment, and thus improving patient outcomes.

The infratranstentorial subtemporal approach (ITSTA): a valuable skull base approach to deep-seated non-skull base pathology.

BACKGROUND: Surgical access to space-occupying lesions such as tumors and vascular malformations located in the area of the tentorial notch, mediobasal temporal lobe, and para-midbrain is difficult. Lesions in this area are typically resected with supratentorial approaches demanding significant elevation of the temporal lobe or even partial lobectomy, or via a supracerebellar transtentorial approach. We introduce an alternative, the skull base infratranstentorial subtemporal approach (ITSTA), which provides excellent exposure of the incisural area while minimizing risk to the temporal lobe. METHODS: We included consecutive patients with pathology involving the area of the tentorial incisura, para-midbrain, and mediobasal temporal area who underwent surgery via ITSTA from 2012 to 2018. The approach includes partial mastoidectomy, temporal craniotomy, and tentorial section. Space obtained by mastoidectomy provides a sharp high-rising angle-of-attack, significantly diminishing the need for temporal lobe retraction. Surgeries were performed using microsurgical techniques, neuronavigation, and electrophysiological monitoring. Clinical presentation, tumor characteristics, extent of resection, complications, and outcome were retrospectively reviewed under a waiver of informed consent. RESULTS: Nine patients met inclusion criteria (five female, four male; mean age 44 years, range 7-72). They underwent surgery for removal of para-midbrain arteriovenous malformation (AVM, 3/9), medial tentorial meningioma (2/9), mediobasal epidermoid cyst (2/9), oculomotor schwannoma (1/9), or pleomorphic xanthoastrocytoma (PXA) of the fusiform gyrus (1/9). Three AVMs were removed completely; among six patients with tumors, gross total resection was achieved in three and subtotal resection in three. All surgeries were uneventful without complications. There were no new permanent neurological deficits. At late follow-up (mean 42.5 months), eight patients had a Glasgow Outcome Score (GOS) of 5. One 66-year-old female died 18 months after surgery for reasons not related to her disease or surgery. CONCLUSIONS: The ITSTA is a valuable skull base approach for removal of non-skull base pathologies located in the difficult tentorial-incisural parabrainstem area.

Technical note: accuracy and precision in stereotactic stem cell transplantation.

BACKGROUND: While multiple trials have employed stereotactic stem cell transplantation, injection techniques have received little critical attention. Precise cell delivery is critical for certain applications, particularly when targeting deep nuclei. METHODS: Ten patients with a history of ischemic stroke underwent CT-guided stem cell transplantation. Cells were delivered along 3 tracts adjacent to the infarcted area. Intraoperative air deposits and postoperative T2-weighted MRI fluid signals were mapped in relation to calculated targets. RESULTS: The deepest air deposit was found 4.5 ± 1.0 mm (mean ± 2 SEM) from target. The apex of the T2-hyperintense tract was found 2.8 ± 0.8 mm from target. On average, air pockets were found anterior (1.2 ± 1.1 mm, p = 0.04) and superior (2.4 ± 1.0 mm, p < 0.001) to the target; no directional bias was noted for the apex of the T2-hyperintense tract. Location and distribution of air deposits were variable and were affected by the relationship of cannula trajectory to stroke cavity. CONCLUSIONS: Precise stereotactic cell transplantation is a little-studied technical challenge. Reflux of cell suspension and air, and the structure of the injection tract affect delivery of cell suspensions. Intraoperative CT allows assessment of delivery and potential trajectory correction.