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Implantation of deep brain stimulators into subthalmic nucleus: technical approach and magnetic imaging—verified electrode locations

Philip A. Starr, Chadwick W. Christine, Philip V. Theodosopoulos, Nadja Lindsey, Deborah Byrd, Anthony Mosley, and William J. Marks Jr.

Object. Chronic deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a procedure that is rapidly gaining acceptance for the treatment of symptoms in patients with Parkinson disease (PD), but there are few detailed descriptions of the surgical procedure itself. The authors present the technical approach used to implant 76 stimulators into the STNs of patients with PD and the lead locations, which were verified on postoperative magnetic resonance (MR) images.

Methods. Implantation procedures were performed with the aid of stereotactic MR imaging, microelectrode recording (MER) in the region of the stereotactic target to define the motor area of the STN, and intraoperative test stimulation to assess the thresholds for stimulation-induced adverse effects. All patients underwent postoperative MR imaging, which was performed using volumetric gradient-echo and T2-weighted fast—spin echo techniques, computational reformatting of the MR image into standard anatomical planes, and quantitative measurements of lead location with respect to the midcommissural point and the red nucleus. Lead locations were statistically correlated with physiological data obtained during MER and intraoperative test stimulation.

Conclusions. The authors' approach to implantation of DBS leads into the STN was associated with consistent lead placement in the dorsolateral STN, a low rate of morbidity, efficient use of operating room time, and robust improvement in motor function. The mean coordinates of the middle of the electrode array, measured on postoperative MR images, were 11.6 mm lateral, 2.9 mm posterior, and 4.7 mm inferior to the midcommissural point, and 6.5 mm lateral and 3.5 mm anterior to the center of the red nucleus. Voltage thresholds for several types of stimulation-induced adverse effects were predictive of lead location. Technical nuances of the surgery are described in detail.

In Journal of Neurosurgery Volume 97: Issue 2 (Aug 2002)

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Editorial

Endoscopy versus MR imaging

John A. Jane Jr. and Edward R. Laws Jr.

In Journal of Neurosurgery Volume 112: Issue 4 (Apr 2010)

Open access

Microsurgical resection of an intravestibular schwannoma: a review of surgical technique and management considerations

Ramin A. Morshed, Alexander F. Haddad, Kunal P. Raygor, Mary Jue Xu, Charles J. Limb, and Philip V. Theodosopoulos

Intravestibular schwannomas are rare tumors within the intralabyrinthine region and involve different management considerations compared to more common vestibular schwannomas. In this report, the authors review a case of a 52-year-old woman who presented with hearing loss and vestibular symptoms and was found to have a left intravestibular schwannoma. Given her debilitating vestibular symptoms, she underwent microsurgical resection. In this video, the authors review the relevant anatomy, surgical technique, and management considerations in these patients.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2187

In Neurosurgical Focus: Video Volume 5: Issue 2 (Oct 2021): Vestibular Schwannoma Surgery

Free access

Relationship between tumor location, size, and WHO grade in meningioma

Stephen T. Magill, Jacob S. Young, Ricky Chae, Manish K. Aghi, Philip V. Theodosopoulos, and Michael W. McDermott

OBJECTIVE

Prior studies have investigated preoperative risk factors for meningioma; however, no association has been shown between meningioma tumor size and tumor grade. The objective of this study was to investigate the relationship between tumor size and grade in a large single-center study of patients undergoing meningioma resection.

METHODS

A retrospective chart review of patients undergoing meningioma resection at the University of California, San Francisco, between 1985 and 2015 was performed. Patients with incomplete information, spinal meningiomas, multiple meningiomas, or WHO grade III meningiomas were excluded. The largest tumor dimension was used as a surrogate for tumor size. Univariate and multivariate logistic regression models were used to investigate the relationship between tumor grade and tumor size. A recursive partitioning analysis was performed to identify groups at higher risk for atypical (WHO grade II) meningioma.

RESULTS

Of the 1113 patients identified, 905 (81%) had a WHO grade I tumor and in 208 (19%) the tumors were WHO grade II. The median largest tumor dimension was 3.6 cm (range 0.2–13 cm). Tumors were distributed as follows: skull base (n = 573, 51%), convexity/falx/parasagittal (n = 431, 39%), and other (n = 109, 10%). On univariate regression, larger tumor size (p < 0.001), convexity/falx/parasagittal location (p < 0.001), and male sex (p < 0.001) were significant predictors of WHO grade II pathology. After controlling for interactions, multivariate regression found male sex (OR 1.74, 95% CI 1.25–2.43), size 3–6 cm (OR 1.69, 95% CI 1.08–2.66), size > 6 cm (OR 3.01, 95% CI 1.53–5.94), and convexity/falx/parasagittal location (OR 1.83, 95% CI 1.19–2.82) to be significantly associated with WHO grade II. Recursive partitioning analysis identified male patients with tumors > 3 cm as a high-risk group (32%) for WHO grade II meningioma.

CONCLUSIONS

Larger tumor size is associated with a greater likelihood of a meningioma being WHO grade II, independent of tumor location and male sex, which are known risk factors.

In Neurosurgical Focus Volume 44: Issue 4 (Apr 2018): Skull Base Meningiomas: Biology, Medical/Surgical Treatment Strategies, and Outcomes

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Postoperative diffusion-weighted imaging and neurological outcome after convexity meningioma resection

Stephen T. Magill, Minh P. Nguyen, Manish K. Aghi, Philip V. Theodosopoulos, Javier E. Villanueva-Meyer, and Michael W. McDermott

OBJECTIVE

Convexity meningiomas are commonly managed with resection. Motor outcomes and predictors of new deficits after surgery are poorly studied. The objective of this study was to determine whether postoperative diffusion-weighted imaging (DWI) was associated with neurological deficits after convexity meningioma resection and to identify the risk factors for postoperative DWI restriction.

METHODS

A retrospective review of patients who had undergone convexity meningioma resection from 2014 to 2018 was performed. Univariate and multivariate logistic regressions were performed to identify variables associated with postoperative neurological deficits and a DWI signal. The amount of postoperative DWI signal was measured and was correlated with low apparent diffusion coefficient maps to confirm ischemic injury.

RESULTS

The authors identified 122 patients who had undergone a total of 125 operations for convexity meningiomas. The median age at surgery was 57 years, and 70% of the patients were female. The median follow-up was 26 months. The WHO grade was I in 62% of cases, II in 36%, and III in 2%. The most common preoperative deficits were seizures (24%), extremity weakness/paralysis (16%), cognitive/language/memory impairment (16%), and focal neurological deficit (16%). Following resection, 89% of cases had no residual deficit. Postoperative DWI showed punctate or no diffusion restriction in 78% of cases and restriction > 1 cm in 22% of cases. An immediate postoperative neurological deficit was present in 14 patients (11%), but only 8 patients (7%) had a deficit at 3 months postoperatively. Univariate analysis identified DWI signal > 1 cm (p < 0.0001), tumor diameter (p < 0.0001), preoperative motor deficit (p = 0.0043), older age (p = 0.0113), and preoperative embolization (p = 0.0171) as risk factors for an immediate postoperative deficit, whereas DWI signal > 1 cm (p < 0.0001), tumor size (p < 0.0001), and older age (p = 0.0181) were risk factors for deficits lasting more than 3 months postoperatively. Multivariate analysis revealed a DWI signal > 1 cm to be the only significant risk factor for deficits at 3 months postoperatively (OR 32.42, 95% CI 3.3–320.1, p = 0.0002). Further, estimated blood loss (OR 1.4 per 100 ml increase, 95% CI 1.1–1.7, p < 0.0001), older age (OR 1.1 per year older, 95% CI 1.0–1.1, p = 0.0009), middle third location in the sagittal plane (OR 16.9, 95% CI 1.3–216.9, p = 0.0026), and preoperative peritumoral edema (OR 4.6, 95% CI 1.2–17.7, p = 0.0249) were significantly associated with a postoperative DWI signal > 1 cm.

CONCLUSIONS

A DWI signal > 1 cm is significantly associated with postoperative neurological deficits, both immediate and long-lasting. Greater estimated blood loss, older age, tumor location over the motor strip, and preoperative peritumoral edema increase the risk of having a postoperative DWI signal > 1 cm, reflective of perilesional ischemia. Most immediate postoperative deficits will improve over time. These data are valuable when preoperatively communicating with patients about the risks of surgery and when postoperatively discussing prognosis after a deficit occurs.

In Journal of Neurosurgery Volume 135: Issue 4 (Oct 2021)

Open access

Introduction. Vestibular schwannoma surgery

Michael J. Link, Isaac Yang, Fred G. Barker II, Amir Samii, and Philip V. Theodosopoulos

In Neurosurgical Focus: Video Volume 5: Issue 2 (Oct 2021): Vestibular Schwannoma Surgery

Free access

Measuring surgical outcomes in neurosurgery: implementation, analysis, and auditing a prospective series of more than 5000 procedures

Clinical article

Philip V. Theodosopoulos, Andrew J. Ringer, Christopher M. McPherson, Ronald E. Warnick, Charles Kuntz IV, Mario Zuccarello, and John M. Tew Jr.

Object

Health care reform debate includes discussions regarding outcomes of surgical interventions. Yet quality of medical care, when judged as a health outcome, is difficult to define because of impediments affecting accuracy in data collection, analysis, and reporting. In this prospective study, the authors report the outcomes for neurosurgical treatment based on point-of-care interactions recorded in the electronic medical record (EMR).

Methods

The authors' neurosurgery practice collected outcome data for 19 physicians and ancillary personnel using the EMR. Data were analyzed for 5361 consecutive surgical cases, either elective or emergency procedures, performed during 2009 at multiple hospitals, offices, and an ambulatory spine surgery center. Main outcomes included complications, length of stay (LOS), and discharge disposition for all patients and for certain frequently performed procedures. Physicians, nurses, and other medical staff used validated scales to record the hospital LOS, complications, disposition at discharge, and return to work.

Results

Of the 5361 surgical procedures performed, two-thirds were spinal procedures and one-third were cranial procedures. Organization-wide compliance with reporting rates of major complications improved throughout the year, from 80.7% in the first quarter to 90.3% in the fourth quarter. Auditing showed that rates of unreported complications decreased from 11% in the first quarter to 4% in the fourth quarter. Complication data were available for 4593 procedures (85.7%); of these, no complications were reported in 4367 (95.1%). Discharge dispositions reported were home in 86.2%, rehabilitation center in 8.9%, and nursing home in 2.5%. Major complications included culture-proven infection in 0.61%, CSF leak in 0.89%, reoperation within the same hospitalization in 0.38%, and new neurological deficits in 0.77%. For the commonly performed procedures, the median hospital LOS was 3 days for craniotomy for aneurysm or intraaxial tumor and less than 1 day for angiogram, anterior cervical discectomy with fusion, or lumbar discectomy.

Conclusions

With prospectively collected outcome data for more than 5000 surgeries, the authors achieved their primary end point of institution-wide compliance and data accuracy. Components of this process included staged implementation with physician pilot studies and oversight, nurse participation, point-of-service data capture, EMR form modification, data auditing, and confidential surgeon reports.

In Journal of Neurosurgery Volume 117 (2012): Issue 5 (Nov 2012)

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Maximizing the extent of tumor resection during transsphenoidal surgery for pituitary macroadenomas: can endoscopy replace intraoperative magnetic resonance imaging?

Clinical article

Philip V. Theodosopoulos, James Leach, Robert G. Kerr, Lee A. Zimmer, Amanda M. Denny, Bharat Guthikonda, Sebastien Froelich, and John M. Tew Jr.

Object

Endoscopic approaches to pituitary tumors have become an effective alternative to traditional microscopic transsphenoidal approaches. Despite a proven potential to decrease unexpected residual tumor, intraoperative MR (iMR) imaging is infrequently used even in the few operating environments in which such technology is available. Its use is prohibitive because of its cost, increased complexity, and longer operative times. The authors assessed the potential of intrasellar endoscopy to replace the need for iMR imaging without sacrificing the maximum extent of resection.

Methods

In this retrospective study, 27 consecutive patients underwent fully endoscopic resection of pituitary macroadenomas. Intrasellar endoscopy was used to determine the presence of residual tumor within the sella turcica and tumor cavity. Intraoperative MR imaging was used to identify rates of unexpected residual tumor and the need for further tumor resection.

Results

Intraoperative estimates of the extent of tumor resection were correct in 23 patients (85%). Of 4 patients with unacceptable tumor residuals, 3 underwent further tumor resection. After iMR imaging, the rate of successful completion of the planned extent of resection increased to 26 patients (96%). Rates of both endocrinopathy reversal and postoperative complications were consistent with previously published results for microscopic and endoscopic resection techniques.

Conclusions

The findings in this study provided quantitative evidence that intrasellar endoscopy has significant promise for maximizing the extent of tumor resection and is a useful adjunct to surgical approaches to pituitary tumors, particularly when iMR imaging is unavailable. A larger prospective study on the extent of resection following endoscopic transsphenoidal surgery would strengthen these findings.

In Journal of Neurosurgery Volume 112: Issue 4 (Apr 2010)

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Analysis of upfront resection or stereotactic radiosurgery for local control of solid and cystic cerebellar hemangioblastomas

Luis R. Carrete, Ramin A. Morshed, Jacob S. Young, Lauro N. Avalos, Penny K. Sneed, Manish K. Aghi, Michael W. McDermott, and Philip V. Theodosopoulos

OBJECTIVE

The purpose of this study was to identify rates of and risk factors for local tumor progression in patients who had undergone surgery or radiosurgery for the management of cerebellar hemangioblastoma and to describe treatments pursued following tumor progression.

METHODS

The authors conducted a retrospective single-center review of patients who had undergone treatment of a cerebellar hemangioblastoma with either surgery or stereotactic radiosurgery (SRS) between 1996 and 2019. Univariate and multivariate regression analyses were performed to examine factors associated with local tumor control.

RESULTS

One hundred nine patients met the study inclusion criteria. Overall, these patients had a total of 577 hemangioblastomas, 229 of which were located in the cerebellum. The surgical and SRS cohorts consisted of 106 and 123 cerebellar hemangioblastomas, respectively. For patients undergoing surgery, tumors were treated with subtotal resection and gross-total resection in 5.7% and 94.3% of cases, respectively. For patients receiving SRS, the mean target volume was 0.71 cm3 and the mean margin dose was 18.0 Gy. Five-year freedom from lesion progression for the surgical and SRS groups was 99% and 82%, respectively. The surgical and SRS cohorts contained 32% versus 97% von Hippel–Lindau tumors, 78% versus 7% cystic hemangioblastomas, and 12.8- versus 0.56-cm3 mean tumor volumes, respectively. On multivariate analysis, factors associated with local tumor progression in the SRS group included older patient age (HR 1.06, 95% CI 1.03–1.09, p < 0.001) and a cystic component (HR 9.0, 95% CI 2.03–32.0, p = 0.001). Repeat SRS as salvage therapy was used more often for smaller tumor recurrences, and no tumor recurrences of < 1.0 cm3 required additional salvage surgery following repeat SRS.

CONCLUSIONS

Both surgery and SRS achieve high rates of local control of hemangioblastomas. Age and cystic features are associated with local progression after SRS treatment for cerebellar hemangioblastomas. In cases of local tumor recurrence, salvage surgery and repeat SRS are valid forms of treatment to achieve local tumor control, although resection may be preferable for larger recurrences.

In Journal of Neurosurgery Publish Before Print

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Intraventricular meningioma resection and visual outcomes

John P. Andrews, Daniel D. Cummins, Ramin A. Morshed, Benyam Kinde, Manish K. Aghi, Michael W. McDermott, Mitchel S. Berger, and Philip V. Theodosopoulos

OBJECTIVE

Intraventricular meningiomas (IVMs) of the lateral ventricle are rare tumors that present surgical challenges because of their deep location. Visual field deficits (VFDs) are one risk associated with these tumors and their treatment. VFDs may be present preoperatively due to the tumor and mass effect (tumor VFDs) or may develop postoperatively due to the surgical approach (surgical VFDs). This institutional series aimed to review surgical outcomes following resection of IVMs, with a focus on VFDs.

METHODS

Patients who received IVM resection at one academic institution between the years 1996 and 2021 were retrospectively reviewed. Diffusion tensor imaging (DTI) reconstructions of the optic radiations around the tumor were performed from preoperative IVM imaging. The VFD course and resolution were documented.

RESULTS

Thirty-two adult patients underwent IVM resection, with gross-total resection in 30 patients (93.8%). Preoperatively, tumor VFDs were present in 6 patients, resolving after surgery in 5 patients. Five other patients (without preoperative VFD) had new persistent surgical VFDs postoperatively (5/32, 15.6%) that persisted to the most recent follow-up. Of the 5 patients with persistent surgical VFDs, 4 received a transtemporal approach and 1 received a transparietal approach, and all these deficits occurred prior to regular use of DTI in preoperative imaging.

CONCLUSIONS

New surgical VFDs are a common neurological deficit after IVM resection. Preoperative DTI may demonstrate distortion of the optic radiations around the tumor, thus revealing safe operative corridors to prevent surgical VFDs.

In Journal of Neurosurgery Publish Before Print