Step-by-step approach: Stereotaxic surgery for in vivo extracellular field potential recording at the rat Schaffer collateral-CA1 synapse using the eLab system.

In vivo extracellular field potential recording is a commonly used technique in modern neuroscience research. The success of long-term electrophysiological recordings often depends on the quality of the implantation surgery. However, there is limited use of visually guided stereotaxic neurosurgery and the application of the eLab/ePulse electrophysiology system in rodent models. This study presents a practical and functional manual guide for surgical electrode implantation in rodent models using the eLab/ePulse electrophysiology system for recording and stimulation purposes to assess neuronal functionality and synaptic plasticity. The evaluation parameters included the input/output function (IO), paired-pulse facilitation or depression (PPF/PPD), long-term potentiation (LTP), and long-term depression (LTD).•Provides a detailed picture-guided procedure for conducting in vivo stereotaxic neurosurgery.•Specifically covers the insertion of hippocampal electrodes and the recording of evoked extracellular field potentials.

Comparison of prone and upright, stereotactic, and tomosynthesis-guided biopsies with secondary analysis of ultrasound-occult architectural distortions.

OBJECTIVES: Compare prone and upright, stereotactic, and tomosynthesis-guided vacuum-assisted breast biopsies (prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB) in a community-practice setting and review outcomes of ultrasound-occult architectural distortions (AD). METHODS: Consecutive biopsies performed at two community-based breast centers from 2016 to 2019 were retrospectively reviewed. Technical details of each procedure and patient outcomes were recorded. Separate analyses were performed for ultrasound-occult ADs. Two sample t-tests and Fisher's exact test facilitated comparisons. RESULTS: A total of 1133 patients underwent 369 prone DM-VABB, 324 prone DBT-VABB, 437 upright DM-VABB, and 123 upright DBT-VABB with 99.2%, 100%, 99.3%, and 99.2% success, respectively (p-values > 0.25). Mean lesion targeting times were greater for prone biopsy (minutes: 6.94 prone DM-VABB, 8.54 prone DBT-VABB, 5.52 upright DM-VABB, and 5.51 upright DBT-VABB; p-values < 0.001), yielding longer total prone procedure times for prone biopsy (p < 0.001). Compared to DM-VABB, DBT-VABB used fewer exposures (p < 0.001) and more commonly targeted AD, asymmetries, or masses (p < 0.001). Malignancy rates were similar between procedures: prone DM-VABB 22.4%, prone DBT-VABB 21.9%, upright DM-VABB 22.8%, and upright DBT-VABB 17.2% (p-values > 0.19). One hundred forty of the 1133 patients underwent 145 biopsies for ultrasound-occult AD (143 DBT-VABB and 2 DM-VABB). Biopsy yielded 27 malignancies and 47 high-risk lesions (74 of 145, 51%). Malignancy rate was 20.7% after surgical upgrade of one benign-discordant and two high-risk lesions. CONCLUSIONS: All biopsy procedure types were extremely successful. The 20.7% malignancy rate for ultrasound-occult AD confirms a management recommendation for tissue diagnosis. Upright biopsy was faster than prone biopsy, and DBT-VABB used fewer exposures than DM-VABB. CLINICAL RELEVANCE: Our results highlight important differences between prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB. Moreover, the high likelihood of malignancy for ultrasound-occult AD will provide confidence in recommending tissue diagnosis in lieu of observation or clinical follow-up. KEY POINTS: • Upright and prone stereotactic and tomosynthesis-guided breast biopsies were safe and effective in the community-practice setting. • The malignancy rate for ultrasound-occult architectural distortion of 20.7% confirms the management recommendation for biopsy. • Upright procedures were faster than prone procedures, and tomosynthesis-guided biopsy used fewer exposures than stereotactic biopsy.

A prospective multicentre trial on survival after Microwave Ablation VErsus Resection for Resectable Colorectal liver metastases (MAVERRIC).

AIM: This multi-centre prospective cohort study aimed to investigate non-inferiority in patients' overall survival when treating potentially resectable colorectal cancer liver metastasis (CRLM) with stereotactic microwave ablation (SMWA) as opposed to hepatic resection (HR). METHODS: Patients with no more than 5 CRLM no larger than 30 mm, deemed eligible for both SMWA and hepatic resection at the local multidisciplinary team meetings, were deliberately treated with SMWA (study group). The contemporary control group consisted of patients with no more than 5 CRLM, none larger than 30 mm, treated with HR, extracted from a prospectively maintained nationwide Swedish database. After propensity-score matching, 3-year overall survival (OS) was compared as the primary outcome using Kaplan-Meier and Cox regression analyses. RESULTS: All patients in the study group (n = 98) were matched to 158 patients from the control group (mean standardised difference in baseline covariates = 0.077). OS rates at 3 years were 78% (Confidence interval [CI] 68-85%) after SMWA versus 76% (CI 69-82%) after HR (stratified Log-rank test p = 0.861). Estimated 5-year OS rates were 56% (CI 45-66%) versus 58% (CI 50-66%). The adjusted hazard ratio for treatment type was 1.020 (CI 0.689-1.510). Overall and major complications were lower after SMWA (percentage decrease 67% and 80%, p < 0.01). Hepatic retreatments were more frequent after SMWA (percentage increase 78%, p < 0.01). CONCLUSION: SMWA is a valid curative-intent treatment alternative to surgical resection for small resectable CRLM. It represents an attractive option in terms of treatment-related morbidity with potentially wider options regarding hepatic retreatments over the future course of disease.

Frameless Robot-Assisted Asleep Centromedian Thalamic Nucleus Deep Brain Stimulation Surgery in Patients with Drug-Resistant Epilepsy: Technical Description and Short-Term Clinical Results.

INTRODUCTION: This purpose of this work is to give a detailed description of a surgical technique for frameless robot-assisted asleep deep brain stimulation (DBS) of the centromedian thalamic nucleus (CMT) in drug-resistant epilepsy (DRE). METHODS: Ten consecutively enrolled patients who underwent CMT-DBS were included in the study. The FreeSurfer "Thalamic Kernel Segmentation" module and experience target coordinates were used for locating the CMT, and quantitative susceptibility mapping (QSM) images were used to check the target. The patient's head was secured with a head clip, and electrode implantation was performed with the assistance of the neurosurgical robot Sinovation®. After opening the dura, the burr hole was continuously flushed with physiological saline to stop air from entering the skull. All procedures were performed under general anesthesia without intraoperative microelectrode recording (MER). RESULTS: The mean age of the patients at surgery and onset of seizures was 22 years (range 11-41 years) and 11 years (range 1-21 years), respectively. The median duration of seizures before CMT-DBS surgery was 10 years (2-26 years). CMT was successfully segmented, and its position was verified by experience target coordinates and QSM images in all ten patients. The mean surgical time for bilateral CMT-DBS in this cohort was 165 ± 18 min. The mean pneumocephalus volume was 2 cm3. The median absolute errors in the x-, y-, and z-axes were 0.7 mm, 0.5 mm, and 0.9 mm, respectively. The median Euclidean distance (ED) and radial error (RE) was 1.3 ± 0.5 mm and 1.0 ± 0.3 mm, respectively. No significant difference was found between right- and left-sided electrodes regarding the RE nor the ED. After a mean 12-month follow-up, the average reduction in seizures was 61%, and six patients experienced a ≥ 50% reduction in seizures, including one patient who had no seizures after the operation. All patients tolerated the anesthesia operation, and no permanent or serious complications were reported. CONCLUSIONS: Frameless robot-assisted asleep surgery is a precise and safe approach for placing CMT electrodes in patients with DRE, shortening the surgery time. The segmentation of the thalamic nuclei enables the precise location of the CMT, and the flow of physiological saline to seal the burr holes is a good way to reduce the influx of air. CMT-DBS is an effective method to reduce seizures.

Outcomes After Endoscopic Evacuation Versus Evacuation Using Craniotomy or Stereotactic Aspiration for Spontaneous Intracerebral Hemorrhage: Analysis Using a Japanese Nationwide Database.

BACKGROUND: Various surgical methods are available for managing large intracerebral hemorrhage. This study compared the prognosis of patients with spontaneous intracerebral hemorrhage who underwent endoscopic evacuation, stereotactic aspiration, and craniotomy by using a nationwide inpatient database in Japan. METHODS: Using the Diagnosis Procedure Combination database, we identified patients who underwent surgery for spontaneous intracerebral hemorrhage within 48 h after admission between April 2014 and March 2018. Eligible patients were classified into three groups according to the type of surgery (endoscopic surgery, stereotactic surgery, and craniotomy). Propensity score matching weight analysis was conducted to compare poor modified Rankin Scale score at discharge (severe disability or death) and hospitalization cost among the groups. RESULTS: Among 17,860 eligible patients, craniotomy, stereotactic surgery, and endoscopic surgery were performed in 14,354, 474, and 3,032 patients, respectively. In the matching weight analysis, all covariates were well balanced. Compared with the endoscopic surgery group, the proportion of poor prognosis (modified Rankin Scale score at discharge of 5 or 6) was significantly higher in craniotomy groups (odds ratio 2.51, 95% confidence interval 1.11-5.68; p = 0.028). Subgroup analysis based on hemorrhage location and consciousness level at the time of admission showed no significant difference between the surgical procedures. Hospitalization costs were significantly higher in the craniotomy group than in the endoscopic surgery group (difference US $9,724, 95% confidence interval 2,169-17,259; p = 0.011). CONCLUSIONS: Endoscopic surgery for spontaneous intracerebral hemorrhage was associated with improved prognosis compared with craniotomy at the hospital discharge. Future large-scale clinical trials are needed to evaluate the optimal surgical techniques for intracerebral hemorrhage.

Clinical study of stereotactic subtentorial approach for brainstem puncture and drainage in the treatment of brain stem hemorrhage in elderly patients / 中华老年医学杂志

Objective:To observe the curative effect of stereotactic subtentorial approach for brainstem puncture and drainage on brain stem hemorrhage in elderly patients.Methods:The clinical data of elderly patients with brain stem hemorrhage admitted to the Department of Neurosurgery, Shangqiu First People 's Hospital from April 2018 to April 2022 were retrospectively analyzed.According to the inclusion and exclusion criteria, a total of 65 elderly patients with brainstem hemorrhage who were treated with stereotactic subtentorial approach for brain stem puncture and drainage, and had complete follow-up data within 90 days after operation were selected.The patient's data were reviewed.The operation time, hematoma clearance rate on the first day after operation, the drainage tube extraction of hematoma cavity, and the postoperative complications were recorded.The follow-up results at 30 days and 90 days after the operation were also recorded.The 30-day Glasgow outcome scale(GOS)was used to evaluate the short-term clinical outcomes of surviving patients, while the modified Rankin score was used to evaluate the neurological function recovery of surviving patients at 90 days.Results:The operation time of the 65 patients was 1.1-2.8 h, with an average of(1.9±0.4)h.On the first day after operation, CT scan showed that the hematoma clearance rate was(84.6±13.6)%.The drainage tube in hematoma cavity was removed within 3-5 days, and there was no puncture-related intracerebral hemorrhage or drainage tube-related intracranial infection after operation.During 30 days of follow-up, 9 patients died and 56 patients survived, with a survival rate of 86.2%.Among the surviving patients, 5 were temporarily in vegetative state and 51 were awake, with varoius degrees of disability.The preoperative hematoma volume of the surviving patients was significantly less than that of the dead patients, and the preoperative GCS score was significantly lower than that of the dead patients( Z=2.386, 2.009, P=0.017, 0.045). After 90 days of follow-up, 3 patients died and 53 survived, with a survival rate of 81.54%.Among the surviving patients, the neurological function of 22 patients recovered well, and the effective rate of clinical treatment was 41.51%. Conclusions:Stereotactic subtentorial approach for brain stem puncture and drainage is an effective and relatively safe surgical method for the treatment of brain stem hemorrhage in elderly patients.

The clinical effect of stereotactic radiation therapy combined with sorafenib in the treatment of primary hepatic cancer / 中国医师进修杂志

Objective:To investigate the clinical effect of stereotactic radiation therapy combined with sorafenib in the treatment of primary hepatic cancer (PHC).Methods:Ninety-two PHC patients admitted to Cancer Hospital of China Medical University from January 2017 to May 2018 were selected and divided into the observation group and the control group according to the random number table method, with 46 cases in each group. The control group was treated with stereotactic radiation therapy, and the observation group was treated with sorafenib on the basis of the control group. Clinical efficacy and incidence of adverse reactions in the two groups were compared; the scores of Karnofsky performance scale (KPS) and the levels of serum vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hypoxia-inducing factor (HIF-1α), soluble interleukin-2 receptor (sIL-2R), transforming growth factor (TGF-β1) and alpha-fetoprotein (AFP) before and after the treatment between the two groups were compared. The overall survival (OS) of patients in both groups was recorded after 36 months of follow-up.Results:The total effective rate in the observation group was higher than that in the control group: 84.78%(39/46) vs. 65.22%(30/46), there was statistical difference ( χ2 = 4.70, P<0.05). After the treatment, the score of KPS in the observation group was higher than that in the control group: (85.06 ± 7.19) scores vs. (71.16 ± 7.08) scores; the levels of VEGF, bFGF, HIF-1α, AFP, TGF-β1, sIL-2R in the observation group were lower than those in the control group: (189.52 ± 31.47) ng/L vs. (235.81 ± 35.45) ng/L, (3.89 ± 0.97) ng/L vs. (6.74 ± 1.85) ng/L, (50.17 ± 6.09) ng/L vs. (53.07 ± 6.28) ng/L, (85.76 ± 14.09) μg/L vs. (131.51 ± 18.74) μg/L, (81.07 ± 12.96) μg/L vs. (106.58 ± 15.07) μg/L, (311.58 ± 74.81) kU/L vs. (405.97 ± 85.74) kU/L, there were statistical differences ( P<0.05). The results of 36 months follow-up showed that the 1-year and 3-year OS in the observation group were higher than those in the control group: 69.57% (32/46) vs. 58.70% (27/46), 43.47% (20/46) vs. 28.26 %(13/46), there were significant differences ( χ2 = 4.78, 3.94, P<0.05). Conclusions:Stereotactic radiation therapy combined with sorafenib can effectively improve the efficacy of PHC patients, reduce the expression of VEGF and bFGF, effectively inhibit tumor growth, but also prolong the survival time of patients, with both safety and high effectiveness, and good use value.

Concordance and diagnostic yield of stereotactic biopsies for posterior fossa: Technique and experience in a reference hospital.

AIM: Describe our stereotactic brain biopsy (SBB) technique for intra-axial lesions of the posterior fossa, evaluate its effectiveness and safety, and compare them with other series. MATERIAL AND METHODS: Retrospective study in ten consecutive patients, whose variables were age, gender, location of the lesions, clinical, radiological, and histopathological diagnoses, complications, and mortality, for analysis using descriptive statistics and tests of concordance and diagnostic validity. RESULTS: Lesions were pontine in seven cases, and pontomedullary in three occasions, with histopathological diagnoses of four Grade II astrocytomas, two Grade IV astrocytomas, two infectious process, one neuroblastic tumor, and one cavernous malformation, whose frequency differs from the previous reports (χ2 = 0.07). The clinical-radiological concordance was poor (κ = 0.20). The validity of the clinical diagnosis had intermediate values (Sn = 66.7%, Sp = 75%), while radiological studies were more sensitive (Sn = 100%, Sp = 25%). A definitive diagnosis was obtained in all procedures, with no permanent morbidity or mortality because of the surgery. CONCLUSION: The SBB technique for posterior fossa implemented in our hospital shows high diagnostic yield, as well as absolute safety for the patient.

OBJETIVO: Describir nuestra técnica de biopsia cerebral estereotáctica (SBB) para lesiones intraaxiales de fosa posterior, evaluar su eficacia y seguridad y compararlas con otras series. MATERIAL Y MÉTODOS: Estudio retrospectivo en 10 pacientes consecutivos, cuyas variables fueron edad, sexo, localización de las lesiones, diagnósticos clínicos, radiológicos e histopatológicos, complicaciones y mortalidad, para análisis mediante estadística descriptiva y pruebas de concordancia y validez diagnóstica. RESULTADOS: Las lesiones fueron pontinas en 7 casos y pontomedulares en 3 ocasiones, con diagnósticos histopatológicos de 4 astrocitomas grado II, 2 astrocitomas grado IV, 2 procesos infecciosos, 1 tumor neuroblástico y 1 malformación cavernosa, cuya frecuencia difiere de reportes previos (χ2 = 0.07). La concordancia clínico-radiológica fue mala (κ = 0.20). La validez del diagnóstico clínico tuvo valores intermedios (Sn = 66.7%, Sp = 75%), mientras que los estudios radiológicos fueron más sensibles (Sn = 100%, Sp = 25%). Se obtuvo un diagnóstico definitivo en todos los procedimientos, sin morbimortalidad permanente por la cirugía. CONCLUSIÓN: La técnica SBB para fosa posterior implementada en nuestro hospital muestra un alto rendimiento diagnóstico, así como una seguridad absoluta para el paciente.

Is 9-G DBT-Guided Vacuum-Assisted Breast Biopsy Sufficient to Completely Remove T1 Breast Cancers (below 20 mm)? Analysis of 146 Patients with Histology as Reference Standard.

Objectives: Vacuum-assisted breast biopsy (VABB) is a safe procedure comparable to surgical biopsy for the characterization of distortions, microcalcifications, and mass lesions. Vacuum-assisted excision of T1 breast tumors could be on potential management in alternative to surgery. The primary objective of this work was to assess the therapeutic success of the stereotaxic vacuum breast biopsy in small breast cancer (T1N0M0) lesions excision. Methods: From our electronic database, all the vacuum breast biopsies performed from January 1, 2015, to December 1, 2019, have been retrospectively reevaluated. N = 2,200 cases were identified and n = 145 ensured "mammographic complete removal" at the end of vacuum-assisted excision treatment and were considered for analysis. Surgical gold standard was used. Results: N = 143 procedures were successfully completed with complete removal of mammographic calcifications. The mean size of the lesions completely excised with VABB was 8.9 ± 3.6 mm (range, 3-23 mm). Lesions below 10 mm were n = 118 and lesion with diameter >10 mm were n = 28. N = 3/146 cases (4.4%), relapses were observed in follow-up (at 12-24 up to a maximum of 60 months): the mean size of relapsed lesions completely excised was 3.6 ± 2.1 mm (range, 2-6 mm). No relapse before 12 months were observed. The mean size of the lesions in these patients with relapse at the time of the first VABB procedures was 13 ± 6.5 mm (range, 7-12 mm). N = 117/118 (99%) lesions excised using VABB without relapse after 1 year of follow-up had a diameter below 10 mm. Conclusions: Vacuum breast biopsy could safely remove small breast cancers (T1N0M0) with few relapses.

Stereotactic and Robotic Minimally Invasive Thermal Ablation of Malignant Liver Tumors: A Systematic Review and Meta-Analysis.

BACKGROUND: Stereotactic navigation techniques aim to enhance treatment precision and safety in minimally invasive thermal ablation of liver tumors. We qualitatively reviewed and quantitatively summarized the available literature on procedural and clinical outcomes after stereotactic navigated ablation of malignant liver tumors. METHODS: A systematic literature search was performed on procedural and clinical outcomes when using stereotactic or robotic navigation for laparoscopic or percutaneous thermal ablation. The online databases Medline, Embase, and Cochrane Library were searched. Endpoints included targeting accuracy, procedural efficiency, and treatment efficacy outcomes. Meta-analysis including subgroup analyses was performed. RESULTS: Thirty-four studies (two randomized controlled trials, three prospective cohort studies, 29 case series) were qualitatively analyzed, and 22 studies were included for meta-analysis. Weighted average lateral targeting error was 3.7 mm (CI 3.2, 4.2), with all four comparative studies showing enhanced targeting accuracy compared to free-hand targeting. Weighted average overall complications, major complications, and mortality were 11.4% (6.7, 16.1), 3.4% (2.1, 5.1), and 0.8% (0.5, 1.3). Pooled estimates of primary technique efficacy were 94% (89, 97) if assessed at 1-6 weeks and 90% (87, 93) if assessed at 6-12 weeks post ablation, with remaining between-study heterogeneity. Primary technique efficacy was significantly enhanced in stereotactic vs. free-hand targeting, with odds ratio (OR) of 1.9 (1.2, 3.2) (n = 6 studies). CONCLUSIONS: Advances in stereotactic navigation technologies allow highly precise and safe tumor targeting, leading to enhanced primary treatment efficacy. The use of varying definitions and terminology of safety and efficacy limits comparability among studies, highlighting the crucial need for further standardization of follow-up definitions.

Specific movement and disability improvements in Burke-Fahn-Marsden Dystonia Rating Scale derived from pallidotomy in refractory patients to medical treatment.

BACKGROUND: Dystonia is a movement disorder associated with significant disability and is usually refractory to medical treatment. Pallidotomy may decrease dystonic movements. The aim of this study was to quantify movement and disability improvements through Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). METHODS: We carried out a longitudinal clinical study in patients with refractory primary and secondary dystonia, who underwent radiofrequency (RF) unilateral and bilateral lesions on the postero-ventro-lateral globus pallidus internus (GPi), evaluating the outcomes through BFMDRS and variables as age, time of evolution, etiology, body distribution, planned target coordinates, and lesion size, during a mean follow-up time of 35.67 months. RESULTS: Nine RF pallidotomies were performed on 6 patients, 7 right-sided and 2 left-sided; three patients were treated unilaterally for one occasion, while the others underwent 2 surgeries, including one staged bilateral procedure. Mean BFMDRS scores for movement were 38.5 preoperative and 25.5 postoperative, and for disability were 20.4 preoperative and 17.3 postoperative. We noticed improvement in movement (32.54%, p = 0.001) and disability (17.23%, p = 0.002). There was one right GPi and internal capsule (IC) infarction with contralateral hemiparesis as sequelae. CONCLUSIONS: RF pallidotomy is an effective and accessible procedure to reduce BFMDRS scores in refractory dystonia if patients are correctly selected by severity, evolution, and disability as determining factors.

Intraoperative ultrasound-guided compared to stereotactic navigated ventriculoperitoneal shunt placement: study protocol for a randomised controlled study.

BACKGROUND: Ventriculoperitoneal shunt (VPS) placement is one of the most frequent neurosurgical procedures and the operation is performed in a highly standardised manner under maintenance of highest infection precautions. Short operation times are important since longer duration of surgery can increase the risk for VPS complications, especially infections. The position of the proximal ventricular catheter influences shunt functioning and survival. With freehand placement, rates of malpositioned VPS are still high. Several navigation techniques for improvement of shunt placement have been developed. Studies comparing these techniques are sparse. The aim of this study is to prospectively compare ultrasound (US) guided to stereotactic navigated shunt placement using optical tracking with the focus on operation time and efficiency. METHODS: In this prospective randomised, single-centre, partially-blinded study, we will include all patients undergoing VPS placement in our clinic. The patients will be randomised into two groups, one group undergoing US-guided (US-G) and the other group stereotactic navigated VPS placement using optical tracking. The primary outcome will be the surgical intervention time. This time span consists of the surgical preparation time together with the operation time and is given in minutes. Secondary outcomes will be accuracy of catheter positioning, VPS dysfunction and need for revision surgery, total operation and anaesthesia times, and amount of intraoperative ventricular puncture attempts as well as complications, any morbidity and mortality. DISCUSSION: To date, there is no prospective data available comparing these two navigation techniques. A randomised controlled study is urgently needed in order to provide class I evidence for the best possible surgical technique of this frequent surgery. TRIAL REGISTRATION: Business Administration System for Ethical Committees (BASEC) 2019-02157, registered on 21 November 2019, https://www.kofam.ch/de/studienportal/suche/88135/studie/49552 ; clinicalTrials.gov: NCT04450797 , registered on 30 June 2020.

Transcranial Magnetic Resonance Imaging-Guided Focused Ultrasound with a 1.5 Tesla Scanner: A Prospective Intraindividual Comparison Study of Intraoperative Imaging.

BACKGROUND: High-quality intraoperative imaging is needed for optimal monitoring of patients undergoing transcranial MR-guided Focused Ultrasound (tcMRgFUS) thalamotomy. In this paper, we compare the intraoperative imaging obtained with dedicated FUS-Head coil and standard body radiofrequency coil in tcMRgFUS thalamotomy using 1.5-T MR scanner. METHODS: This prospective study included adult patients undergoing tcMRgFUS for treatment of essential tremor. Intraoperative T2-weighted FRFSE sequences were acquired after the last high-energy sonication using a dedicated two-channel FUS-Head (2ch-FUS) coil and body radiofrequency (body-RF) coil. Postoperative follow-ups were performed at 48 h using an eight-channel phased-array (8ch-HEAD) coil. Two readers independently assessed the signal-to-noise ratio (SNR) and evaluated the presence of concentric lesional zones (zone I, II and III). Intraindividual differences in SNR and lesional findings were compared using the Wilcoxon signed rank sum test and McNemar test. RESULTS: Eight patients underwent tcMRgFUS thalamotomy. Intraoperative T2-weighted FRFSE images acquired using the 2ch-FUS coil demonstrated significantly higher SNR (R1 median SNR: 10.54; R2: 9.52) compared to the body-RF coil (R1: 2.96, p < 0.001; R2: 2.99, p < 0.001). The SNR was lower compared to the 48-h follow-up (p < 0.001 for both readers). Intraoperative zone I and zone II were more commonly visualized using the 2ch-FUS coil (R1, p = 0.031 and p = 0.008, R2, p = 0.016, p = 0.008), without significant differences with 48-h follow-up (p ≥ 0.063). The inter-reader agreement was almost perfect for both SNR (ICC: 0.85) and lesional findings (k: 0.82-0.91). CONCLUSIONS: In the study population, the dedicated 2ch-FUS coil significantly improved the SNR and visualization of lesional zones on intraoperative imaging during tcMRgFUS performed with a 1.5-T MR scanner.

Robot-Assisted Stereotactic Biopsies in 377 Consecutive Adult Patients with Supratentorial Diffuse Gliomas: Diagnostic Yield, Safety, and Postoperative Outcomes.

BACKGROUND: Multiple biopsy samples are warranted for the histomolecular diagnosis of diffuse gliomas in the current molecular era, which possibly increases morbidity. OBJECTIVE: We assessed diagnostic yield, safety, and risk factors of postoperative morbidity after robot-assisted serial stereotactic biopsy sampling along 1 biopsy trajectory for diffuse gliomas. METHODS: Observational retrospective analysis of consecutive magnetic resonance imaging-based robot-assisted stereotactic biopsies performed at a single institution to assess the diagnosis of nonresectable newly diagnosed supratentorial diffuse gliomas in adults (2006-2016). RESULTS: In 377 patients, 4.2 ± 1.9 biopsy samples were obtained at 2.6 ± 1.2 biopsy sites. The histopathologic diagnosis was obtained in 98.7% of cases. Preoperative neurologic deficit (P = 0.030), biopsy site hemorrhage ≥20 mm (P = 0.004), and increased mass effect on postoperative imaging (P = 0.014) were predictors of a new postoperative neurologic deficit (7.7%). Postoperative neurologic deficit (P < 0.001) and increased mass effect on postoperative imaging (P = 0.014) were predictors of a Karnofsky Performance Status decrease ≥20 points postoperatively (4.0%). Increased intracranial pressure preoperatively (P = 0.048) and volume of the contrast-enhanced area ≥13 cm3 (P = 0.048) were predictors of an increased mass effect on postoperative imaging (4.4%). Preoperative Karnofsky Performance Status <70 (P = 0.045) and increased mass effect on postoperative imaging (P < 0.001) were predictors of mortality 1 month postoperatively (2.9%). Preoperative neurologic deficit (P = 0.005), preoperative Karnofsky Performance Status <70 (P < 0.001), subventricular zone contact (P = 0.004), contrast enhancement (P = 0.018), and steroid use (P = 0.003), were predictors of the inability to discharge to home postoperatively (37.0%). CONCLUSIONS: Robot-assisted stereotactic biopsy sampling results in high diagnostic accuracy with low complication rates. Multiple biopsy sites and samples do not increase postoperative complications.

Utility of image-guided external ventriculostomy: analysis of contemporary practice in the United Kingdom and Ireland.

OBJECTIVE: Freehand external ventricular drain (EVD) insertion is associated with a high rate of catheter misplacement. Image-guided EVD placement with neuronavigation or ultrasound has been proposed as a safer, more accurate alternative with potential to facilitate proper placement and reduce catheter malfunction risk. This study aimed to determine the impact of image-guided EVD placement on catheter tip position and drain functionality. METHODS: This study is a secondary analysis of a data set from a prospective, multicenter study. Data were collated for EVD placements undertaken in the United Kingdom and Ireland from November 2014 to April 2015. In total, 21 large tertiary care academic medical centers were included. RESULTS: Over the study period, 632 EVDs were inserted and 65.9% had tips lying free-floating in the CSF. Only 19.6% of insertions took place under image guidance. The use of image guidance did not significantly improve the position of the catheter tip on postoperative imaging, even when stratified by ventricular size. There was also no association between navigation use and drain blockage. CONCLUSIONS: Image-guided EVD placement was not associated with an increased likelihood of achieving optimal catheter position or with a lower rate of catheter blockage. Educational efforts should aim to enhance surgeons' ability to apply the technique correctly in cases of disturbed cerebral anatomy or small ventricles to reduce procedural risks and facilitate effective catheter positioning.

Transcranial magnetic resonance-guided focused ultrasound thalamotomy as a safe treatment option in multiple sclerosis patients with essential tremor.

Transcranial magnetic resonance-guided focused ultrasound is a recently introduced incisionless treating option for essential tremor and tremor-dominant idiopathic Parkinson disease. There is preliminary evidence that it may result in a promising effective treatment option for other movement disorders too. Here, we report on two patients with multiple sclerosis with medication refractory debilitating essential tremor comorbidity who successfully underwent unilateral Vim tcMRgFUS thalamotomy for tremor control. Patients' clinical condition and expanded disability status scale scores showed no changes during the 1-year follow-up period with no evidence of multiple sclerosis activity or progression.

Clip migration after stereotactic vacuum-assisted breast biopsy with the patient in the decubitus position.

OBJECTIVE: To investigate the factors contributing to clip migration in stereotactic vacuum-assisted biopsy (VAB) of the breast using an upright unit with the patient in the decubitus position. METHODS: This retrospective study included 176 women with microcalcifications on mammograms undergoing stereotactic VAB with clip marking for analysis. The prebiopsy mammograms, stereotactic VAB images, immediate postbiopsy mammograms, and follow-up mammograms were reviewed. All VAB procedures were performed using an add-on upright unit with the patient in the decubitus position. The clip-to-lesion distance on the orthogonal view (craniocaudal view) on immediate postbiopsy mammography was estimated for each biopsy. Two cutoff points of clip-to-lesion distance of > 1 cm or > 2 cm were set for clip migration. The possible factors for clip migration based on clinical and imaging findings were then analyzed by Fisher's exact test. RESULTS: When the cutoff for clip migration was set at > 1 cm, thin breast (p = 0.013) and more superficial lesion (lesion closer to the skin along the line perpendicular to the posterior nipple line, p = 0.004) were associated with clip migration. When the cutoff was set at > 2 cm, thin breast (p = 0.019), high specimen number (p = 0.030), and posterior depth (p = 0.021) were associated with clip migration. CONCLUSIONS: Thin breasts, superficial lesion location, posterior lesion depth, and high specimen number were the factors associated with clip migration. KEY POINTS: • We reported clip migration after ST VAB using an upright unit with the patient in the decubitus position. • The occurrence of clinically significant clip migration (> 2 cm) in our study was 8.5%, which was within the range of the other reports with the patient undergoing ST VAB in the prone position. • Thin breasts, high specimen number, and more posterior depth were the factors associated with significant clip migration.

Stereotactic Image-Guided Microwave Ablation for Malignant Liver Tumors-A Multivariable Accuracy and Efficacy Analysis.

Background: Therapeutic success of thermal ablation for liver tumors depends on precise placement of ablation probes and complete tumor destruction with a safety margin. We investigated factors influencing targeting accuracy and treatment efficacy of percutaneous stereotactic image-guided microwave ablation (SMWA) for malignant liver neoplasms. Materials and methods: All consecutive patients treated with SMWA for malignant liver tumors over a 3-year period were analyzed. A computed tomography-based navigation system was used for ablation probe trajectory planning, stereotactic probe positioning, and validation of probe positions and ablation zones. Factors potentially influencing targeting accuracy [target positioning error (TPE)] and treatment efficacy within 6 months [ablation site recurrence (ASR)] were analyzed in a multivariable regression model, including challenging lesion locations (liver segments I, VII, and VIII; subphrenic location). Results: Three hundred one lesions (174 hepatocellular carcinomas, 87 colorectal liver metastases, 17 neuroendocrine tumors, and 23 others) were targeted in 191 interventions in 153 patients. The median TPE per ablation probe was 2.9 ± 2.3 mm (n = 384). Correction of ablation probe positions by repositioning was necessary in 4 out of 301 lesions (1%). Factors significantly influencing targeting accuracy were cirrhosis (R 0.67, CI 0.22-1.12) and targeting trajectory length (R 0.21, CI 0.12-0.29). Factors significantly influencing early ASR were lesion size >30 mm (OR 5.22, CI 2.44-11.19) and TPE >5 mm (OR 2.48, CI 1.06-5.78). Challenging lesion locations had no significant influence on targeting accuracy or early ASR. Conclusions: SMWA allows precise and effective treatment of malignant liver tumors even for lesions in challenging locations, with treatment efficacy depending on targeting accuracy in our model. Allowing for many tumors to be safely reached, SMWA has the potential to broaden treatment eligibility for patients with otherwise difficult to target tumors.

Intraoperative imaging findings in transcranial MR imaging-guided focused ultrasound treatment at 1.5T may accurately detect typical lesional findings correlated with sonication parameters.

OBJECTIVES: To assess the intraoperative neuroimaging findings in patients treated with transcranial MR-guided focused ultrasound (tcMRgFUS) thalamotomy using 1.5T equipment in comparison with the 48-h follow-up. METHODS: Fifty prospectively enrolled patients undergoing unilateral tcMRgFUS thalamotomy for either medication-refractory essential tremor (n = 39) or Parkinson tremor (n = 11) were included. Two radiologists evaluated the presence and size of concentric lesional zones (zone I, zone II, and zone III) on 2D T2-weighted sequences acquired intraoperatively after the last high-energy sonication and at 48 h. Sonication parameters including number of sonications, delivered energy, and treatment temperatures were also recorded. Differences in lesion pattern and size were assessed using the McNemar test and paired t test, respectively. RESULTS: Zones I, II, and III were visualized in 34 (68%), 50 (100%), and 44 (88%) patients, and 31 (62%), 50 (100%), and 45 (90%) patients after the last high-energy sonication for R1 and R2, respectively. All three concentric zones were visualized intraoperatively in 56-58% of cases. Zone I was significantly more commonly visualized at 48 h (p < 0.001). Diameter of zones I and II and the thickness of zone III significantly increased at 48 h (p < 0.001). Diameters of zones I and II measured intraoperatively demonstrated significant correlation with thermal map temperatures (p ≤ 0.001). Maximum temperature significantly correlated with zone III thickness at 48 h. A threshold of 60.5° had a sensitivity of 56.5-66.7% and a specificity of 70.5-75.5% for thickness > 6 mm at 48 h. CONCLUSIONS: Intraoperative imaging may accurately detect typical lesional findings, before completing the treatment. These imaging characteristics significantly correlate with sonication parameters and 48-h follow-up. KEY POINTS: • Intraoperative T2-weighted images allow the visualization of the zone I (coagulation necrosis) in most of the treated patients, while zone II (cytotoxic edema) is always detected. • Lesion size depicted with intraoperative transcranial MRgFUS imaging correlates well with procedure parameters. • Intraoperative transcranial MRgFUS imaging may have a significant added value for treating physicians.

Computer-assisted navigation in complex cervical spine surgery: tips and tricks.

Stereotactic navigation is quickly establishing itself as the gold standard for accurate placement of spinal instrumentation and providing real-time anatomic referencing. There have been substantial improvements in computer-aided navigation over the last decade producing improved accuracy with intraoperative scanning while shortening registration time. The newest iterations of modeling software create robust maps of the anatomy while tracking software localizes instruments in multiple display modes. As a result, stereotactic navigation has become an effective adjunct to spine surgery, particularly improving instrumentation accuracy in the setting of atypical anatomy. This article provides an overview of stereotactic navigation applied to complex cervical spine surgery, details the means for registration and direct referencing, and shares our preferred methods to implement this promising technology.