BACKGROUND Modern robotic-assist surgical systems have revolutionized stereotaxy for a variety of procedures by increasing operative efficiency while preserving and even improving accuracy and safety. However, experience with robotic systems in deep brain stimulation (DBS) surgery is scarce. OBJECTIVE To present an initial series of DBS surgery performed utilizing a frameless robotic solution for image-guided stereotaxy, and report on operative efficiency, stereotactic accuracy, and complications. METHODS This study included the initial 20 consecutive patients undergoing bilateral robot-assisted DBS. The prior 20 nonrobotic, frameless cohort of DBS cases was sampled as a baseline historic control. For both cohorts, patient demographic and clinical data were collected including postoperative complications. Intraoperative duration and number of Microelectrode recording (MER) and final lead passes were recorded. For the robot-assisted cohort, 2D radial errors were calculated. RESULTS Mean case times (total operating room, anesthesia, and operative times) were all significantly decreased in the robot-assisted cohort (all P-values < .02) compared to frameless DBS. When looking at trends in case times, operative efficiency improved over time in the robot-assisted cohort across all time assessment points. Mean radial error in the robot-assisted cohort was 1.40 ± 0.11 mm, and mean depth error was 1.05 ± 0.18 mm. There was a significant decrease in the average number of MER passes in the robot-assisted cohort (1.05) compared to the nonrobotic cohort (1.45, P < .001). CONCLUSION This is the first report of application of frameless robotic-assistance with the Mazor Renaissance platform (Mazor Robotics Ltd, Caesarea, Israel) for DBS surgery, and our findings reveal that an initial experience is safe and can have a positive impact on operative efficiency, accuracy, and safety.

CNS involvement in the setting of lymphoid neoplasia is a clinical situation that requires specific diagnosis due to the disparate treatment regimens recommended for neoplasms of specific lymphoid cell types. Cerebrospinal fluid (CSF) sampling may provide sufficient information to determine the presence of abnormal lymphoid cells but may not be able to further specify the malignant cellular population. In cases where abnormal clinical or radiographic features are present, accurate tissue diagnosis is essential. In this report, we define a rare case of primary CNS intramedullary Hodgkin's lymphoma without leptomeningeal dissemination diagnosed via resectional biopsy of a conus medullaris lesion. The patient received post-resection radiation therapy and subsequently demonstrated radiographic and clinical improvement. Lymphoid neoplasia within the CNS comprises a diverse group with varying response and survival rates. Treatment hinges upon accurate diagnosis as chemotherapy varies widely among Hodgkin's and non-Hodgkin's lymphoma. While CSF sampling may yield a positive result with sufficiency to diagnose an abnormal lymphoid cell population, tissue is necessary for further defining cellular pathology. In this report, we define a rare case of primary CNS intramedullary Hodgkin's lymphoma without leptomeningeal dissemination via resectional biopsy of a conus medullaris lesion. In cases where abnormal enhancement is found in eloquent CNS regions and lymphoid neoplasia is suspected, management often entails either stereotactic biopsy or CSF sampling. While CSF analysis may differentiate malignancy at a low rate, tissue diagnosis via paraffin block immunohistochemistry is necessary to further classify malignancy as primary or peripheral, Hodgkin's or non-Hodgkin's lymphoma, or other such as metastatic leptomeningeal dissemination and glioma. Within the subtypes of lymphoid neoplasms, treatment regimens vastly differ and thus accurate tissue diagnosis is paramount. We therefore present a rare case of primary CNS intramedullary Hodgkin's lymphoma without leptomeningeal disease in the setting of immunocompromise diagnosed via open resectional biopsy of the conus medullaris.

eWe describe the use of PCR and electrospray ionization followed by mass spectrometry (PCR/ESI-MS) to evaluate "culture-negative" cerebrospinal fluid (CSF) from a 67-year-old man who developed postoperative bacterial ventriculitis following a suboccipital craniotomy for resection of an ependymoma in the 4th ventricle. CSF samples were obtained on seven occasions, beginning in the operating room at the time of insertion of a right ventriculoperitoneal shunt (VPS) and continuing until his death, 6 weeks later. During the course of the illness, two initial CSF specimens taken before the initiation of antimicrobial treatment were notable for growth of Enterococcus faecalis. Once antimicrobial treatment was initiated, all CSF cultures were negative. PCR/ESI-MS detected genetic evidence of E. faecalis in all CSF samples, but the level of detection (LOD) decreased once antimicrobial treatment was initiated. When our patient returned with symptoms of meningitis 3 days after the completion of antibiotic treatment, CSF cultures remained negative, but PCR/ESI-MS again found genetic evidence for E. faecalis at levels comparable to the pretreatment levels seen initially. This unique case and these findings suggest that determination of CSF LOD by PCR/ESI-MS may be a very sensitive indicator of persistent infection in patients on antibiotic therapy for complex CNS infections and may have relevance for treatment duration and assessment of persistent or recurrent infection at the completion of therapy. CASE REPORTA 67-year-old non-insulin-dependent diabetic man with a history of hypertension and coronary artery disease presented for evaluation of ataxia. He complained of approximately 3 months of "listing to the right upon walking"; this symptom was associated with gradually worsening headaches, nausea and vomiting, vertigo, and tremors. Other than tremor and a positive Romberg sign, results of the patient's examination were unremarkable. The examination showed that motor, sensory, and cranial nerves were intact. A mass consistent with an ependymoma was discovered in the 4th ventricle on magnetic resonance imaging (MRI) of the brain. Due to the significant mass effect and suspicion of malignancy, resection was indicated, and he was scheduled for resection of the 4th ventricle mass.A suboccipital craniotomy was performed. Preoperative cefazolin antibiotic prophylaxis was administered. After tumor resection, the dura was closed. Pathological examination of the fourth ventricular tumor was consistent with a mixed ependymoma/subependymoma, World Health Organization grade II. The morning following surgery, diplopia developed. Postoperative MRI of the brain demonstrated complete resection without complication. A pseudomeningocele was noted in the soft tissues, although no CSF leak was noted at the wound; a computed tomography (CT) scan of the head 24 h postoperation demonstrated hydrocephalus, prompting insertion of a right frontal external ventricular drain (EVD). The CSF appeared normal. At this time, CSF was not submitted for cult...

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