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Adetokunbo A. Oyelese, Jared Fridley, David B. Choi, Albert Telfeian, and Ziya L. Gokaslan

Upper lumbar (L1–2, L2–3) disc herniations are distinct in their diffuse presenting clinical symptomatology and have poorer outcomes with surgical intervention than those following mid and lower lumbar disc herniations and disc surgery. The authors present the cases of 3 patients with L1–2 disc herniations and significant stenosis of the spinal canal. The surgical approach used here combined the principles of transforaminal percutaneous endoscopic discectomy and the extreme lateral lumbar interbody fusion procedures with intraoperative CT-guided navigational assistance. The approach provides a safe corridor of direct visualization to the ventral thecal sac with minimal bony resection and could, in principle, reduce neurological injury and biomechanical instability, which likely contribute to poor outcomes at this level.

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David J. Chalif, Eugene S. Flamm, Alex Berenstein, and In Sup Choi

✓ A complication of treatment of posttraumatic carotid-cavernous fistulas by detachable balloon techniques is presented. During occlusion of the fistula, a balloon embolus migrated from the cavernous sinus into the bifurcation of the internal carotid artery. The resultant neurological deficit was immediately treated with hypertension and volume expansion. The patient underwent direct microsurgical embolectomy and suffered no postoperative neurological sequelae. The significance and management of this complication are discussed.

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Nitin Agarwal, Phillip A. Choi, David O. Okonkwo, Daniel L. Barrow, and Robert M. Friedlander


Application for a residency position in neurosurgery is a highly competitive process. Visiting subinternships and interviews are integral parts of the application process that provide applicants and programs with important information, often influencing rank list decisions. However, the process is an expensive one that places significant financial burden on applicants. In this study, the authors aimed to quantify expenses incurred by 1st-year neurosurgery residents who matched into a neurosurgery residency program in 2014 and uncover potential trends in expenses.


A 10-question survey was distributed in partnership with the Society of Neurological Surgeons to all 1st-year neurosurgery residents in the United States. The survey asked respondents about the number of subinternships, interviews, and second looks (after the interview) attended and the resultant costs, the type of program match, preferences for subinternship interviews, and suggestions for changes they would like to see in the application process. In addition to compiling overall results, also examined were the data for differences in cost when stratifying for region of the medical school or whether the respondent had contact with the program they matched to prior to the interview process (matched to home or subinternship program).


The survey had a 64.4% response rate. The mean total expenses for all components of the application process were US $10,255, with interview costs comprising the majority of the expenses (69.0%). No difference in number of subinternships, interviews, or second looks attended, or their individual and total costs, was seen for applicants from different regions of the United States. Respondents who matched to their home or subinternship program attended fewer interviews than respondents who had no prior contact with their matched program (13.5 vs 16.4, respectively, p = 0.0023) but incurred the same overall costs (mean $9774 vs $10,566; p = 0.58).


Securing a residency position in neurosurgery is a costly process for applicants. No differences are seen when stratifying by region of medical school attended or contact with a program prior to interviewing. Interview costs comprise the majority of expenses for applicants, and changes to the application process are needed to control costs incurred by applicants.

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Clemens M. Schirmer, Steven W. Hwang, Ron I. Riesenburger, In Sup Choi, and Carlos A. David

Cobb syndrome represents the concurrent findings of a metameric spinal vascular malformation and a cutaneous vascular malformation within several dermatomes of each other. This rare entity engenders many difficult decisions with respect to appropriate therapeutic management. Historically, surgical excision carried a high morbidity, and conservative management without intervention was preferred. More recently, several cases of endovascular embolization have been reported with good success.

The authors describe the case of a 17-year-old boy who presented with a right gluteal angioma and was found to have a spinal arteriovenous malformation. Multiple embolizations failed to prevent neurological deterioration, and the patient eventually became wheelchair dependent. Surgical excision of the malformation led to partial recovery of neurological function, and at the latest follow-up, 52 months postoperatively, the patient was able to ambulate independently. This case demonstrates the successful treatment of a patient with Cobb syndrome with surgical excision after multiple refractory embolizations. A multidisciplinary approach, which balances the patient's current neurological function against the risks and potential gains from any interventional and surgical procedure, is recommended.

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Anouk Borg, Ciaran Scott Hill, Besnik Nurboja, Giles Critchley, and David Choi


Lumbar spinal stenosis (LSS) is a common and debilitating condition that is increasing in prevalence in the world population. Surgical decompression is often standard treatment when conservative measures have failed. Interspinous distractor devices (IDDs) have been proposed as a safe alternative; however, the associated cost and early reports of high failure rates have brought their use into question. The primary objective of this study was to determine the cost-effectiveness and long-term quality-of-life (QOL) outcomes after treatment of LSS with the X-Stop IDD compared with surgical decompression by laminectomy.


A multicenter, open-label randomized controlled trial of 47 patients with LSS was conducted; 21 patients underwent insertion of the X-Stop device and 26 underwent laminectomy. The primary outcomes were monetary cost and QOL measured using the EQ-5D questionnaire administered at 6-, 12-, and 24-month time points.


The mean monetary cost for the laminectomy group was £2712 ($3316 [USD]), and the mean cost for the X-Stop group was £5148 ($6295): £1799 ($2199) procedural cost plus £3349 mean device cost (£2605 additional cost per device). Using an intention-to-treat analysis, the authors found that the mean quality-adjusted life-year (QALY) gain for the laminectomy group was 0.92 and that for the X-Stop group was 0.81. The incremental cost-effectiveness ratio was −£22,145 (−$27,078). The revision rate for the X-Stop group was 19%. Five patients crossed over to the laminectomy arm after being in the X-Stop group.


Laminectomy was more cost-effective than the X-Stop for the treatment of LSS, primarily due to device cost. The X-Stop device led to an improvement in QOL, but it was less than that in the laminectomy group. The use of the X-Stop IDD should be reserved for cases in which a less-invasive procedure is required. There is no justification for its regular use as an alternative to decompressive surgery.

Clinical trial registration no.: ISRCTN88702314 (

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John D. Steichen, Robert B. Stewart, David N. Louis, Benjamin B. Choi, Robert Kung, and Robert L. Martuza

✓ The 1.9-µ wavelength component of a 1.9/1.06-µ two-wavelength laser with near-continuous wave properties was tested for its potential use in neurosurgery. The 1.9-µ wavelength has tissue-ablative capabilities, while the 1.06-µ wavelength (Nd:YAG) is suitable for achieving hemostasis. The advantages of the 1.9-µ wavelength over the CO2 laser include its ability to transmit through silica fiberoptic delivery systems and its deeper penetration in water (approximately 100 µ, a depth 10 times greater than for the CO2 laser), which is compatible with irrigation during ablation.

To test the effectiveness of the laser, bilateral craniotomies were performed in anesthetized rats immobilized in a stereotactic frame. Under an operating microscope, lesions were made on the cortex by delivering the 1.9-µ laser beam through a 400-µ fiber at an average power of 1 W over a range of fluences. Subjective intraoperative observations were notable for minimal bleeding, absence of charring when the tissue was irrigated with a thin stream of saline, and uniform lesion formation. For comparison, lesions were generated with a commercially available continuous-wave CO2 laser at equivalent power and fluences. Histological specimens were divided into three groups based on the study after laser application: acute (30 minutes), subacute (48 hours), and chronic (14 days). The extent of thermal injury for the 1.9-µ laser in the acute lesions was quantitatively and histologically similar to that generated by the CO2 laser. Regions of injury extended approximately from the apex of the lesion, and crater depths generated by both lasers were similar (250 to 750 µ) in the range of fluences investigated (1.25 to 10 kJ/sq cm). Subacute and chronic histological specimens demonstrated inflammatory and repair responses that correlated with the acute injury regions in both the 1.9-µ and CO2 laser-treated specimens.

This study demonstrates a neurosurgical potential for a new two-wavelength laser that ablates tissue effectively with limited thermal injury. The 1.9-µ laser is comparable to the widely used CO2 laser but offers several unique advantages, including the ability for delivery through a fiberoptic system and to irrigate tissue during use.

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Hani J. Marcus, David Choi, and Neil L. Dorward

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Bryan D. Choi, Michael R. DeLong, David M. DeLong, Allan H. Friedman, and John H. Sampson


The purpose of this study was to report the prevalence of neurosurgeons with both medical degrees (MDs) and doctorates (PhDs) at top-ranked US academic institutions and to assess whether the additional doctorate education is associated with substantive career involvement in academia as well as greater success in procuring National Institutes of Health (NIH) research funding compared with an MD-only degree.


The authors reviewed the training of neurosurgeons across the top 10 neurosurgery departments chosen according to academic impact (h index) to examine whether MD-PhD training correlated significantly with career outcomes in academia.


Six hundred thirteen neurosurgery graduates and residents between the years 1990 and 2012 were identified for inclusion in this analysis. Both MD and PhD degrees were held by 121 neurosurgeons (19.7%), and an MD alone was held by 492. Over the past 2 decades, MD-PhD trainees represented a gradually increasing percentage of neurosurgeons, from 10.2% to 25.7% (p < 0.01). Of the neurosurgeons with MD-PhD training, a greater proportion had appointments in academic medicine compared with their MD-only peers (73.7% vs 52.3%, p < 0.001). Academic neurosurgeons with both degrees were also more likely to have received NIH funding (51.9% vs 31.8%, p < 0.05) than their single-degree counterparts in academia. In a national analysis of all active NIH R01 grants awarded in neurosurgery, MD-PhD investigators held a disproportionate number, more than 4-fold greater than their representation in the field.


Dual MD-PhD training is a significant factor that may predict active participation in and funding for research careers among neurological surgeons at top-ranked academic institutions. These findings and their implications are of increasing relevance as the population of neurosurgeons with dual-degree training continues to rise.