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Christopher M. Lee, Gordon A. Watson, and Dennis D. Leavitt

Object

The purpose of this study was to determine the effect of static and dynamic collimator optimization when using a micromultileaf collimator (mMLC) in dynamic-arc stereotactic radiosurgery (SRS) by evaluating the dose to healthy peritumoral tissue.

Methods

Thirty patients previously treated for intracranial lesions with the BrainLAB mMLC underwent retrospective replanning. Three collimator optimization strategies were compared for a simulated SRS treatment plan, as follows: Strategy 1, static collimation fixed at 90° throughout arcs; Strategy 2, static collimator settings optimized for each arc; and Strategy 3, dynamic collimator settings optimized every 10° throughout treatment arcs. Dose–volume histograms for a 0.7-cm shell of healthy peritumoral tissue were quantitatively compared.

Collimator optimization schemes (Strategies 2 and 3) significantly decreased the volume of peritumoral tissue that is irradiated when compared with static collimation at 90° (Strategy 1). The volume was reduced by 40.6% for Strategy 2 (95% confidence interval [CI] ± 11) and by 47.1% for Strategy 3 (95% CI ± 8.1) at the 95% isodose; by 28.4% for Strategy 2 (95% CI ± 4.9) and 39.1% for Strategy 3 (95% CI ± 6) at the 90% isodose; and by 18.2% for Strategy 2 (95% CI ± 8.1) and 25.4% for Strategy 3 (95% CI ± 7.1) at the 80% isodose. Serial collimator optimization throughout the treatment arcs (Strategy 3) reduced the mean volume of peritumoral tissue irradiated when compared with static collimator optimization (Strategy 2), by 16.1% (95% CI ± 1.5) at 95% isodose, by 11.7% (95% CI ± 1) at 90% isodose, and by 8.2% (95% CI ± 1.2) at 80% isodose regions. In specific cases, linear or polynomial functions were formulated to optimize collimator settings dynamically throughout treatment arcs.

Conclusions

Dynamic collimator optimization during arc-based SRS decreases the volume of healthy peritumoral tissue treated with high doses of radiation and appears to be an effective method of improving target conformality. This study is the first step toward determination of a smoothing function algorithm to allow for true dynamic collimation during SRS.

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Wenya Linda Bi, Ryan Brewster, Dennis Poe, David Vernick, Daniel J. Lee, C. Eduardo Corrales, and Ian F. Dunn

Superior semicircular canal dehiscence (SSCD) syndrome is an increasingly recognized cause of vestibular and/or auditory symptoms in both adults and children. These symptoms are believed to result from the presence of a pathological mobile “third window” into the labyrinth due to deficiency in the osseous shell, leading to inadvertent hydroacoustic transmissions through the cochlea and labyrinth. The most common bony defect of the superior canal is found over the arcuate eminence, with rare cases involving the posteromedial limb of the superior canal associated with the superior petrosal sinus. Operative intervention is indicated for intractable or debilitating symptoms that persist despite conservative management and vestibular sedation. Surgical repair can be accomplished by reconstruction or plugging of the bony defect or reinforcement of the round window through a variety of operative approaches. The authors review the etiology, pathophysiology, presentation, diagnosis, surgical options, and outcomes in the treatment of this entity, with a focus on potential pitfalls that may be encountered during clinical management.

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Jonathan B. Lamano, Robert A. Riestenberg, Aden P. Haskell-Mendoza, Dennis Lee, Michael T. Sharp, and Orin Bloch

OBJECTIVE

Patients increasingly utilize online physician review websites (PRWs) and social media to inform healthcare-related decisions. This provides neurosurgeons with opportunities for increased patient engagement. And despite the growing use of social media among neurosurgeons, the relationship between social media utilization and online reviews remains unknown. The goal of this study was to characterize the relationship between social media utilization and PRW ratings across academic neurosurgery departments.

METHODS

Social media accounts (Twitter, Facebook, YouTube, Instagram) of academic neurosurgery departments were identified. Online reviews for individual faculty were obtained from Healthgrades, Vitals, WebMD, and Google. Reviews were aggregated to identify the total number of reviews per department, to generate a composite departmental rating, and to calculate a summed departmental score. US News & World Report (USNWR) and Doximity rankings were recorded for each department. Social media utilization by individual neurosurgeons and associated ratings were investigated within the departments with the highest social media utilization.

RESULTS

Seventy-eight percent of academic neurosurgery departments utilized social media. The most prevalent platform was YouTube (49.1%), followed by Twitter (46.5%), Facebook (38.6%), and Instagram (16.7%). Higher patient ratings on PRWs were associated with the utilization of YouTube (p = 0.048) or Twitter (p = 0.02). The number of social media platforms utilized demonstrated a significant, positive correlation with patient ratings (p = 0.006) and summed patient ratings (p = 0.048). Although USNWR (p = 0.02) and Doximity (p = 0.0008) rankings correlated with patient ratings, only the number of social media platforms utilized remained a significant predictor of patient ratings on multivariate analysis (p = 0.0001). Thirty-one percent of academic neurosurgeons from departments with high social media utilization were active on social media. The most prevalent social media platform among individual neurosurgeons was Twitter (27.4%), followed by Instagram (8.4%), Facebook (4.9%), and YouTube (2.2%). Higher summed patient scores were associated with individual neurosurgeon utilization of YouTube (p = 0.04), Facebook (p < 0.0001), and Instagram (p = 0.01). Increased social media utilization among neurosurgeons was correlated with a greater number of patient reviews (p = 0.006) and higher summed patient scores (p = 0.003). On multivariate analysis, only Facebook use remained a significant predictor of the number of patient reviews received (p = 0.002) and summed patient satisfaction scores (p < 0.001).

CONCLUSIONS

An increased social media presence is associated with higher ratings on PRWs. As neurosurgeons continue to expand their online presence, they should be aware of the possible impact of social media on online patient reviews.

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Matthias Oertel, Daniel F. Kelly, David McArthur, W. John Boscardin, Thomas C. Glenn, Jae Hong Lee, Tooraj Gravori, Dennis Obukhov, Duncan Q. McBride, and Neil A. Martin

Object. Progressive intracranial hemorrhage after head injury is often observed on serial computerized tomography (CT) scans but its significance is uncertain. In this study, patients in whom two CT scans were obtained within 24 hours of injury were analyzed to determine the incidence, risk factors, and clinical significance of progressive hemorrhagic injury (PHI).

Methods. The diagnosis of PHI was determined by comparing the first and second CT scans and was categorized as epidural hematoma (EDH), subdural hematoma (SDH), intraparenchymal contusion or hematoma (IPCH), or subarachnoid hemorrhage (SAH). Potential risk factors, the daily mean intracranial pressure (ICP), and cerebral perfusion pressure were analyzed. In a cohort of 142 patients (mean age 34 ± 14 years; median Glasgow Coma Scale score of 8, range 3–15; male/female ratio 4.3:1), the mean time from injury to first CT scan was 2 ± 1.6 hours and between first and second CT scans was 6.9 ± 3.6 hours. A PHI was found in 42.3% of patients overall and in 48.6% of patients who underwent scanning within 2 hours of injury. Of the 60 patients with PHI, 87% underwent their first CT scan within 2 hours of injury and in only one with PHI was the first CT scan obtained more than 6 hours postinjury. The likelihood of PHI for a given lesion was 51% for IPCH, 22% for EDH, 17% for SAH, and 11% for SDH. Of the 46 patients who underwent craniotomy for hematoma evacuation, 24% did so after the second CT scan because of findings of PHI. Logistic regression was used to identify male sex (p = 0.01), older age (p = 0.01), time from injury to first CT scan (p = 0.02), and initial partial thromboplastin time (PTT) (p = 0.02) as the best predictors of PHI. The percentage of patients with mean daily ICP greater than 20 mm Hg was higher in those with PHI compared with those without PHI. The 6-month postinjury outcome was similar in the two patient groups.

Conclusions. Early progressive hemorrhage occurs in almost 50% of head-injured patients who undergo CT scanning within 2 hours of injury, it occurs most frequently in cerebral contusions, and it is associated with ICP elevations. Male sex, older age, time from injury to first CT scan, and PTT appear to be key determinants of PHI. Early repeated CT scanning is indicated in patients with nonsurgically treated hemorrhage revealed on the first CT scan.

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Christian P. DiPaola, Nicolas Dea, Marcel F. Dvorak, Robert S. Lee, Dennis Hartig, and Charles G. Fisher

Object

Conflict of interest (COI) as it applies to medical education and training has become a source of considerable interest, debate, and regulation in the last decade. Companies often pay surgeons as faculty for educational events and often sponsor and give financial support to major professional society meetings. Professional medical societies, industry, and legislators have attempted to regulate potential COI without consideration for public opinion. The practice of evidence-based medicine requires the inclusion of patient opinion along with best available evidence and expert opinion. The primary goal of this study was to assess the opinion of the general population regarding surgeon-industry COI for education-related events.

Methods

A Web-based survey was administered, with special emphasis on the surgeon's role in industry-sponsored education and support of professional societies. A survey was constructed to sample opinions on reimbursement, disclosure, and funding sources for educational events.

Results

There were 501 completed surveys available for analysis. More than 90% of respondents believed that industry funding for surgeons' tuition and travel for either industry-sponsored or professional society educational meetings would either not affect the quality of care delivered or would cause it to improve. Similar results were generated for opinions on surgeons being paid by industry to teach other surgeons. Moreover, the majority of respondents believed it was ethical or had no opinion if surgeons had such a relationship with industry. Respondents were also generally in favor of educational conferences for surgeons regardless of funding source. Disclosures of a surgeon-industry relationship, especially if it involves specific devices that may be used in their surgery, appears to be important to respondents.

Conclusions

The vast majority of respondents in this study do not believe that the quality of their care will be diminished due to industry funding of educational events, for surgeon tuition, and/or travel expenses. The results of this study should help form the basis of policy and continued efforts at surgeon-industry COI management.

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Anthony C. Wang, George M. Ibrahim, Andrew V. Poliakov, Page I. Wang, Aria Fallah, Gary W. Mathern, Robert T. Buckley, Kelly Collins, Alexander G. Weil, Hillary A. Shurtleff, Molly H. Warner, Francisco A. Perez, Dennis W. Shaw, Jason N. Wright, Russell P. Saneto, Edward J. Novotny, Amy Lee, Samuel R. Browd, and Jeffrey G. Ojemann

OBJECTIVE

The potential loss of motor function after cerebral hemispherectomy is a common cause of anguish for patients, their families, and their physicians. The deficits these patients face are individually unique, but as a whole they provide a framework to understand the mechanisms underlying cortical reorganization of motor function. This study investigated whether preoperative functional MRI (fMRI) and diffusion tensor imaging (DTI) could predict the postoperative preservation of hand motor function.

METHODS

Thirteen independent reviewers analyzed sensorimotor fMRI and colored fractional anisotropy (CoFA)–DTI maps in 25 patients undergoing functional hemispherectomy for treatment of intractable seizures. Pre- and postoperative gross hand motor function were categorized and correlated with fMRI and DTI findings, specifically, abnormally located motor activation on fMRI and corticospinal tract atrophy on DTI.

RESULTS

Normal sensorimotor cortical activation on preoperative fMRI was significantly associated with severe decline in postoperative motor function, demonstrating 92.9% sensitivity (95% CI 0.661–0.998) and 100% specificity (95% CI 0.715–1.00). Bilaterally robust, symmetric corticospinal tracts on CoFA-DTI maps were significantly associated with severe postoperative motor decline, demonstrating 85.7% sensitivity (95% CI 0.572–0.982) and 100% specificity (95% CI 0.715–1.00). Interpreting the fMR images, the reviewers achieved a Fleiss’ kappa coefficient (κ) for interrater agreement of κ = 0.69, indicating good agreement (p < 0.01). When interpreting the CoFA-DTI maps, the reviewers achieved κ = 0.64, again indicating good agreement (p < 0.01).

CONCLUSIONS

Functional hemispherectomy offers a high potential for seizure freedom without debilitating functional deficits in certain instances. Patients likely to retain preoperative motor function can be identified prior to hemispherectomy, where fMRI or DTI suggests that cortical reorganization of motor function has occurred prior to the operation.