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Robotic image-guided depth electrode implantation in the evaluation of medically intractable epilepsy

Technical note

William J. Spire, Barbara C. Jobst, Vijay M. Thadani, Peter D. Williamson, Terrance M. Darcey, and David W. Roberts


The authors describe their experience with a technique for robotic implantation of depth electrodes in patients concurrently undergoing craniotomy and placement of subdural monitoring electrodes for the evaluation of intractable epilepsy.


Patients included in this study underwent evaluation in the Dartmouth Surgical Epilepsy Program and were recommended for invasive seizure monitoring with depth electrodes between 2006 and the present. In all cases an image-guided robotic system was used during craniotomy for concurrent subdural grid electrode placement. A total of 7 electrodes were placed in 4 patients within the time period.


Three of 4 patients had successful localization of seizure onset, and 2 underwent subsequent resection. Of the patients who underwent resection, 1 is now seizure free, and the second has only auras. There was 1 complication after subpial grid placement but no complications related to the depth electrodes.


Robotic image-guided placement of depth electrodes with concurrent craniotomy is feasible, and the technique is safe, accurate, and efficient.

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The many roles of microRNAs in brain tumor biology

Jay D. Turner, Richard Williamson, Kaith K. Almefty, Peter Nakaji, Randall Porter, Victor Tse, and M. Yashar S. Kalani

MicroRNAs (miRNAs) are now recognized as the primary RNAs involved in the purposeful silencing of the cell's own message. In addition to the established role of miRNAs as developmental regulators of normal cellular function, they have recently been shown to be important players in pathological states such as cancer. The authors review the literature on the role of miRNAs in the formation and propagation of gliomas and medulloblastomas, highlighting the potential of these molecules and their inhibitors as therapeutics.

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Intradural cauda equina Candida abscess presenting with hydrocephalus: case report

Davis P. Argersinger, Vitaliy P. Natkha, Matthew J. Shepard, Alissa A. Thomas, Andrew J. Oler, Peter R. Williamson, Prashant Chittiboina, and John D. Heiss

Central nervous system (CNS) candida infections are often associated with a poor prognosis. Typically, CNS candidiasis presents as meningitis or microabscesses. Here, the authors report a patient with a challenging presentation of a CNS Candida infection as a discrete, large cauda equina abscess. The patient initially presented with ventriculomegaly due to fourth ventricular outflow obstruction and a cauda equina mass. The patient was treated with a ventriculoperitoneal shunt and underwent a lumbar laminectomy for exploration of the lumbar lesion. An intradural abscess was encountered during surgery. Fungal wet mount revealed fungal elements and polymerase chain reaction confirmed the presence of Candida albicans. The patient did not have any known predisposition to fungal infections; therefore, the authors performed whole-exome sequencing using peripheral blood mononuclear cell DNA. They found heterozygous missense variants in the following genes: colony-stimulating factor 2 (CSF2) and Ras protein-specific guanine nucleotide-releasing factor 1 (RASGRF1)—genes that have been specifically associated with protection from CNS candidiasis via caspase recruitment domain-containing protein 9 (CARD9) signaling, and phospholipase C gamma 2 (PLCG2)—a lectin receptor involved in candidiasis. The authors’ experience suggests that C. albicans can present as a cauda equina abscess. Hydrocephalus, a result of diffuse arachnoiditis, is a potential complication from intradural fungal abscesses.

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Natural history of adult spinal deformity: how do patients with suboptimal surgical outcomes fare relative to nonoperative counterparts?

Peter G. Passias, Rachel Joujon-Roche, Jamshaid M. Mir, Tyler K. Williamson, Peter S. Tretiakov, Bailey Imbo, Oscar Krol, Lara Passfall, Salman Ahmad, Jordan Lebovic, Stephane Owusu-Sarpong, Tomi Lanre-Amos, Themistocles Protopsaltis, Renaud Lafage, Virginie Lafage, Paul Park, Dean Chou, Praveen V. Mummaneni, Kai-Ming G. Fu, Khoi D. Than, Justin S. Smith, M. Burhan Janjua, Andrew J. Schoenfeld, Bassel G. Diebo, and Shaleen Vira


Management of adult spinal deformity (ASD) has increasingly favored operative intervention; however, the incidence of complications and reoperations is high, and patients may fail to achieve idealized postsurgical results. This study compared health-related quality of life (HRQOL) metrics between patients with suboptimal surgical outcomes and those who underwent nonoperative management as a proxy for the natural history (NH) of ASD.


ASD patients with 2-year data were included. Patients who were offered surgery but declined were considered nonoperative (i.e., NH) patients. Operative patients with suboptimal outcome (SOp)—defined as any reoperation, major complication, or ≥ 2 severe Scoliosis Research Society (SRS)–Schwab modifiers at follow-up—were selected for comparison. Propensity score matching (PSM) on the basis of baseline age, deformity, SRS-22 Total, and Charlson Comorbidity Index score was used to match the groups. ANCOVA and stepwise logistic regression analysis were used to assess outcomes between groups at 2 years.


In total, 441 patients were included (267 SOp and 174 NH patients). After PSM, 142 patients remained (71 SOp 71 and 71 NH patients). At baseline, the SOp and NH groups had similar demographic characteristics, HRQOL, and deformity (all p > 0.05). At 2 years, ANCOVA determined that NH patients had worse deformity as measured with sagittal vertical axis (36.7 mm vs 21.3 mm, p = 0.025), mismatch between pelvic incidence and lumbar lordosis (11.9° vs 2.9°, p < 0.001), and pelvic tilt (PT) (23.1° vs 20.7°, p = 0.019). The adjusted regression analysis found that SOp patients had higher odds of reaching the minimal clinically important differences in Oswestry Disability Index score (OR [95% CI] 4.5 [1.7–11.5], p = 0.002), SRS-22 Activity (OR [95% CI] 3.2 [1.5–6.8], p = 0.002), SRS-22 Pain (OR [95% CI] 2.8 [1.4–5.9], p = 0.005), and SRS-22 Total (OR [95% CI] 11.0 [3.5–34.4], p < 0.001).


Operative patients with SOp still experience greater improvements in deformity and HRQOL relative to the progressive radiographic and functional deterioration associated with the NH of ASD. The NH of nonoperative management should be accounted for when weighing the risks and benefits of operative intervention for ASD.

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Oral Presentations 2015 AANS Annual Scientific Meeting Washington, DC • May 2–6, 2015

Published online August 1, 2015; DOI: 10.3171/2015.8.JNS.AANS2015abstracts

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Abstracts of the 2017 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves Las Vegas, Nevada • March 8–11, 2017