ML-13 Primary central nervous system malignant lymphoma in a patient with rheumatoid arthritis receiving tocilizumab

Background: Although the risk of developing malignant lymphoma is higher in patients with rheumatoid arthritis (RA) than in the general population, the occurrence of primary central nervous system lymphoma (PCNSL) in patients with RA is extremely rare. In recent years, there has been concern that biological disease-modifying antirheumatic drugs (DMRADs), which are widely administered to patients with RA, may increase the risk of developing cancer. We report the first case of PCNSL in a patient with RA who was treated with the biological DMRADs, tocilizumab. Case description: A 70-year-old man, who was diagnosed with RA in 2010 was treated with low-dose methotrexate from 2010 to 2015. He was started on tocilizumab in 2012. In 2018, he suffered from gait disturbance and was diagnosed with lumbar spinal stenosis. He underwent L2/3 posterior fusion surgery, but his paraplegia gradually deteriorated. Two months after the surgery, a head Gd-MRI showed multiple contrast-enhanced lesions in the basal ganglia and brain stem. A stereotactic brain biopsy was performed and DLBCL was diagnosed, and finally PCNSL was diagnosed because of no neoplastic lesions in other organs. He was treated with 5 courses of MTX 3.5g/m2 with rituximab and has been in remission for 23 months. He has maintained an independent life with residual paraplegia, but his ADLs gradually worsened. He was restarted on tocilizumab with a diagnosis of worsening RA. Conclusion: Low-dose methotrexate and biological DMRADs including tocilizumab, have been concerned to increase the risk of cancer in patients with RA, but there is no solid evidence. Since it has been a short time since the use of biological DMRADs, further accumulation of cases and careful follow-up are necessary.

Optimized Intraoperative Imaging for Stereotactic Planning with a Multiaxial Robotic C-arm System: Technical Note and Case Series

Background The preoperative preparation of the planning dataset for frame-based stereotactic brain biopsy is often associated with logistical effort and burden on the patient. Intraoperative imaging modalities need to be investigated to overcome these limitations. Objective The objective of the study was to develop and apply a new method for the intraoperative acquisition of the planning dataset with the multiaxial robotic C-arm system Artis zeego. Methods An indication-customized dose-reduced protocol for Artis zeego was developed and implemented into the workflow. A sample of 14 patients who had undergone intraoperative imaging with Artis zeego was analyzed. A sample of 10 patients with conventional preoperative imaging by cranial computed tomography (CT) was used as a control group. Outcomes were compared with regard to target deviation, diagnostic value of the biopsies, complications, and procedure time. Results In all patients, a suitable intraoperative planning dataset could be acquired with Artis zeego. Total procedure time was shorter for the Artis zeego group (p = 0.01), whereas time in the operating room area was longer in the Artis zeego group (p = 0.04). Biopsy results were diagnostic in 12 patients (86%) in the Artis zeego group and in 8 patients (80%) in the control group. There were no significant differences in target size, trajectory length, or target deviation. Conclusion Intraoperative imaging for frame-based stereotactic brain biopsy with Artis zeego is an easy and feasible method. Accuracy is comparable to conventional CT, whereas radiation exposure could be additionally reduced. It allows a significant reduction of the total procedure length and improves the comfort for the patient and staff.

P.157 Frame-based stereotactic brain biopsy: A retrospective review of diagnostic yield and complications at a Canadian Center

Background: Historically, frame-based stereotactic brain biopsy (SBB) has played an important role in the diagnosis of intracranial lesions. We performed a single centre analysis of the outcomes and efficacy of SBB at the London Health Sciences Centre (LHSC). Methods: We performed a retrospective chart review of frame-based SBB from 2006 to 2017 at the LHSC. Intra-operative and final pathology reports were analyzed for biopsy diagnosis and the diagnosis was compared with pre-operative neuroimaging reports for correlation. SBB-associated morbidity and mortality were investigated using chart review and post-operative neuroimaging. Results: 173 consecutive patients were identified. The overall morbidity rate was 8.7% (15 cases) and mortality rate was 0.6% (1 case). Final biopsy diagnostic accuracy was 96%, intra-operative diagnostic accuracy was 94% and pre-operative imaging diagnostic accuracy was 65%. Elevated partial thromboplastin time and the presence of hemorrhage on post-operative CT were associated with neurological morbidity and mortality. The need to obtain three or greater samples the time of biopsy was associated with non-diagnostic biopsy. Conclusions: At the LHSC, SBB is a relatively safe and effective surgical procedure with high diagnostic yield and relatively low risk of complications. Intra-operative pathology has a high efficacy in determining diagnosis when compared to final pathology.

The diagnostic accuracy and era for improvement for frameless stereotactic brain biopsy: a series of 109 procedures and a systemic review

PurposeTo evaluate the diagnostic accuracy of frameless stereotactic brain biopsy and review the era for improvement.MethodsThis is a prospectively collected cohort study from 2007 to 2020. We reviewed patients who received frameless stereotactic brain biopsy in Prince of Wales Hospital and evaluated the diagnostic accuracy of the frameless stereotactic brain biopsy procedures. The biopsy result was classified into conclusive, inconclusive or negative, based on the pathological, radiological and clinical diagnosis concordance. For inconclusive or negative results, we further evaluated the pre-operative planning and post-operative imaging to review if further improvement could be made. The complication rate of symptomatic hemorrhage and mortality rate was also analyzed.ResultsThere were 106 patients with 109 biopsy procedures performed from 2007 to 2020. The conclusive diagnosis was reached in 103 (94.5%) procedures. The inconclusive diagnosis was noted in four (3.7%) procedures and negative diagnosis was yielded in two (1.9%) procedures. Symptomatic hemorrhage was noted in one patient (0.9%). There was no mortality case (0.0%) in our case series. The registration errors occurred in three cases (2.8%), sampling of the non-representative part of the lesion occurred in two cases (1.8%), and one biopsy (0.9%) for lymphoma was negative after the commencement of steroids. Systemic review showed that the diagnostic accuracy under the structurally defined diagnosis criteria was comparable with published literatures in recent ten years.ConclusionThe stereotactic biopsy is a safe procedure with high diagnostic accuracy only if meticulous pre-operative planning and careful intra-operative registration is performed. The common pitfalls precluding a conclusive diagnosis are errors during registration and non-representative biopsy sites.

P07.02 Robot-assisted stereotactic brain biopsy combined with cortical mapping using navigated transcranial magnetic stimulation

BACKGROUND Frame-based stereotactic biopsy has been for decades the gold-standard method for taking samples of brain tumors for the histopathological diagnostic in cases when surgery was contraindicated. However, novel frameless techniques have been developed in order to facilitate the procedure for the neurosurgeon, and for the patient as well. Preoperative cortical mapping techniques enable the planning of the trajectory with the sparing of eloquent areas. MATERIAL AND METHODS A preoperative cortical mapping using navigated transcranial magnetic stimulation was performed in the case of a 37-year-old male that presented with headache. The MRI scan revealed multiple lesions located frontal lobe and temporal lobe on the right hemisphere and frontal and occipital lobes on the left hemisphere. The results of the preoperative cortical mapping were integrated into the neuronavigation system and used for the planning of the frameless based stereotactic brain biopsy. A biopsy procedure was performed using a robotic arm according to the planned trajectory. RESULTS The targeted lesion was the right frontal one. The planned trajectory took into account the results from the cortical mapping using nTMS, and the eloquent areas were avoided. The robotic arm guided the procedure and aligned to the entry point and trajectory. According to the histopathological result the lesion was a grade II diffuse astrocytoma. There were no perioperative complications. CONCLUSION To our knowledge, this is the first report that describes the use of a robot-guided frameless brain biopsy system combined with the preoperative mapping of the eloquent cortical areas using navigated transcranial magnetic stimulation. This approach is a safe one and carries less burden for the patient as well as for the surgeon.

Severity, timeline, and management of complications after stereotactic brain biopsy

OBJECTIVE The literature shows discrepancies in stereotactic brain biopsy complication rates, severities, and outcomes. Little is known about the timeline of postbiopsy complications. This study aimed to analyze 1) complications following brain biopsies, using a graded severity scale, and 2) a timeline of complication occurrence. The secondary objectives were to determine factors associated with an increased risk of complications and to assess complication-related management and extra costs. METHODS The authors retrospectively examined 1500 consecutive stereotactic brain biopsies performed in adult patients at their tertiary medical center between April 2009 and April 2019. RESULTS Three hundred eighty-one biopsies (25.4%) were followed by a complication, including 88.2% of asymptomatic hemorrhages. Symptomatic complications involved 3.0% of the biopsies, and 0.8% of the biopsies were fatal. The severity grading scale had a 97.6% interobserver reproducibility. Twenty-three (51.1%) of the 45 symptomatic complications occurred within the 1st hour following the biopsy, while 75.6% occurred within the first 6 hours. Age ≥ 65 years, second biopsy procedures, gadolinium-enhanced lesions, glioblastomas, and lymphomas were predictors of biopsy-related complications. Brainstem biopsy-targeted lesions and cerebral toxoplasmosis were predictive of mortality. Asymptomatic hemorrhage was associated with delayed (> 6 hours) symptomatic complications. Symptomatic complications led to extended hospitalization in 86.7% of patients. The average extra cost for management of a patient with postbiopsy symptomatic complication was $35,702. CONCLUSIONS Symptomatic complications from brain biopsies are infrequent but associated with substantial adverse effects and cost implications for the healthcare system. The use of a severity grading scale, as the authors propose in this article, helps to classify complications according to the therapeutic consequences and the patient’s outcome. Because this study indicates that most complications occur within the first few hours following the biopsy, postbiopsy monitoring can be tailored accordingly. The authors therefore recommend systematic monitoring for 2 hours in the recovery unit and a CT scan 2 hours after the end of the biopsy procedure. In addition, they propose a modern algorithm for optimal postoperative management of patients undergoing stereotactic biopsy.

Case report of an elderly woman with atypical imaging for primary central nervous system lymphoma who needed a brain biopsy for diagnosis

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma, but its diagnosis is challenging in some cases. A brain biopsy is the gold standard for diagnosing PCNSL, but its invasiveness can be problematic. Thus, noninvasive imaging examinations have been developed for the pre-surgical diagnosis of PCNSL, including gadolinium-enhanced magnetic resonance imaging (MRI), 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (123I-IMP SPECT), and positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG PET). Here, we report the case of a 71-year-old woman with negative imaging findings for PCNSL, but who was diagnosed with PCNSL by a brain biopsy and histological analysis. Her imaging results were negative for gadolinium-enhanced cranial MRI, with low uptake in 123I-IMP SPECT and hypometabolism in 18F-FDG PET. However, a stereotactic brain biopsy from an abnormal lesion revealed that many round cells had infiltrated into the brain. Moreover, many infiltrating cells were positive for cluster of differentiation (CD)20 and CD79a, and proliferation marker protein Ki-67-positive cells accounted for nearly 80% of all cells. Based on these results, our final pathological diagnosis was PCNSL. The present case highlights the possibility of a PCNSL diagnosis even when all imaging-related examinations display negative results.

Review on Factors Affecting Diagnostic Yield in Stereotactic Biopsy for Brain Lesions: A 5-Year Single-Center Series.

Objective: To determine the factors that are associated with the diagnostic yield of stereotactic brain biopsy. Materials and Methods: A retrospective analysis was performed on 50 consecutive patients who underwent stereotactic brain biopsies in a single institute from 2014 to 2019. Variables including age, gender, lesion topography and characteristics, biopsy methods and surgeon’s experience were analyzed along with diagnostic rate. Results: This study included 31 male and 19 female patients with a mean age of 48.4 (range: 1-76). Of these, 25 underwent frameless brain-suite stereotactic biopsies, 15 were frameless portable Brain-lab® stereotactic biopsies and 10 were frame-based CRW® stereotactic biopsies. There was no statistical difference between the diagnostic yield of the three methods. The diagnostic yield in our series was 76%. Age, gender and biopsy methods had no impact on diagnostic yield. Periventricular and pineal lesion biopsies were significantly associated with negative diagnostic yield (p=0.01) whereas larger lesions were significantly associated with a positive yield (p=0.01) with the mean volume of lesions in the positive yield group (13.6cc) being higher than the negative yield group (7cc). The diagnostic yields seen between senior and junior neurosurgeons in the biopsy procedure were 95% and 63% respectively (p=0.02). Conclusion: Anatomical location of the lesion, volume of the lesion and experience of the surgeon have significant impacts on the diagnostic yield in stereotactic brain biopsy. There was no statistical difference between the diagnostic yield of the three methods, age, gender and depth of lesion.