Shivanand P Lad

Duke University Medical Center, Durham, North Carolina, United States

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Publications (84)211.64 Total impact

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    ABSTRACT: Few studies have measured outcome differences between the various available spinal fusion techniques. We compare long-term outcomes of anterior versus posterior lumbar interbody fusion. Using the MarketScan database (Truven Health Analytics, Ann Arbor, MI, USA) we selected patients ⩾18years old who underwent lumbar fusion surgery from 2000-2009 using either approach. Exclusion criteria included circumferential fusion, and having less than 1year of preoperative or less than 2years of postoperative follow-up. Using an inverse probability-weighted propensity-score model we compared reoperation and 90day complication rates, and postoperative health resource utilization of both approaches. A total of 10,941 patients were identified. Of these, 7460 (68.2%) and 3481 (31.8%) underwent posterior and anterior interbody fusion, respectively. Anterior fusion patients had a higher 2year reoperation rate (odds ratio 1.43, 95% confidence interval [CI]: 1.21-1.70, p<0.0001), although differences became non-significant at maximum follow-up (p=0.0877). The 90day complication rate was 15.7%, with anterior fusion patients being more likely to experience complications (relative risk 1.24, 95%CI: 1.13-1.36, p<0.0001). Anterior fusion patients also had greater levels of postoperative health utilization, surpassing posterior fusion patients by an average of $US7450 in total charges (95% CI: $4670-$10,220, p<0.0001). As currently practiced in the USA, anterior lumbar surgical approaches may be associated with higher postoperative morbidity and reoperation rates than posterior fusion approaches. Copyright © 2015. Published by Elsevier Ltd.
    Journal of Clinical Neuroscience. 02/2015;
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    ABSTRACT: Essential tremor (ET) was the original indication for deep brain stimulation (DBS), with USA Food and Drug Administration approval since 1997. Despite the efficacy of DBS, it is associated with surgical complications that cause sub-optimal clinical outcomes. Given that ET is a progressive disease with increase in symptom severity with increasing age, this study evaluated the impact of increasing age on short-term complications following DBS surgery for ET. The Thomson-Reuters MarketScan database was utilized (New York, NY, USA). Patients selected were over age 18 and underwent DBS for ET between the years 2000 and 2009. Multivariable logistic regression analysis was used to calculate complication odds ratios (OR) for a 5year increase in age, after controlling for other covariates. Six hundred sixty-one patients were included in the analysis. The mean (standard deviation) age was 61.9 (14.3) years, with 17% of individuals aged ⩾75years. Overall 56.9% of patients were male, and 44.6% had a Charlson Comorbidity Score of ⩾1. Additionally, 7.1% of patients experienced at least one complication within 90days, including wound infections (3.0%), pneumonia (2.4%), hemorrhage or hematoma (1.5%), or pulmonary embolism (0.6%). Increasing age was not significantly associated with the overall 90day complication rates (OR 0.89; 95% confidence interval [CI] 0.77-1.02; p=0.102). The risk of the two most common procedure-related complications, hemorrhage and infection, did not significantly increase with age (hemorrhage: OR 1.02; 95%CI 0.77-1.37; p=0.873; and infection: OR 0.88; 95%CI 0.72-1.07; p=0.203). Our findings suggest that age should not be a primary exclusion factor for determining candidacy for DBS and also suggest a possible expansion of the traditional therapeutic window since post-operative complications remained relatively stable. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Journal of Clinical Neuroscience 02/2015; · 1.32 Impact Factor
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    Bryan Howell, Shivanand P Lad, Warren M Grill
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    ABSTRACT: Spinal cord stimulation (SCS) is an alternative or adjunct therapy to treat chronic pain, a prevalent and clinically challenging condition. Although SCS has substantial clinical success, the therapy is still prone to failures, including lead breakage, lead migration, and poor pain relief. The goal of this study was to develop a computational model of SCS and use the model to compare activation of neural elements during intradural and extradural electrode placement. We constructed five patient-specific models of SCS. Stimulation thresholds predicted by the model were compared to stimulation thresholds measured intraoperatively, and we used these models to quantify the efficiency and selectivity of intradural and extradural SCS. Intradural placement dramatically increased stimulation efficiency and reduced the power required to stimulate the dorsal columns by more than 90%. Intradural placement also increased selectivity, allowing activation of a greater proportion of dorsal column fibers before spread of activation to dorsal root fibers, as well as more selective activation of individual dermatomes at different lateral deviations from the midline. Further, the results suggest that current electrode designs used for extradural SCS are not optimal for intradural SCS, and a novel azimuthal tripolar design increased stimulation selectivity, even beyond that achieved with an intradural paddle array. Increased stimulation efficiency is expected to increase the battery life of implantable pulse generators, increase the recharge interval of rechargeable implantable pulse generators, and potentially reduce stimulator volume. The greater selectivity of intradural stimulation may improve the success rate of SCS by mitigating the sensitivity of pain relief to malpositioning of the electrode. The outcome of this effort is a better quantitative understanding of how intradural electrode placement can potentially increase the selectivity and efficiency of SCS, which, in turn, provides predictions that can be tested in future clinical studies assessing the potential therapeutic benefits of intradural SCS.
    PLoS ONE 12/2014; 9(12):e114938. · 3.53 Impact Factor
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    ABSTRACT: The aim of this study was to compare reoperation, complication rates, and healthcare resource utilization of expansile laminectomies with instrumented fusion versus laminoplasty. Using the MarketScan database (Truven Health Analytics, Ann Arbor, MI, USA), we selected patients aged >18 years who underwent either cervical laminoplasty or laminectomy with fusion between 2000–2009. Propensity score modeling produced a matched cohort balanced for age, sex, comorbidities, and other relevant factors. A total of 3185 patients meeting our inclusion criteria also had 2 year follow-up available. Of these, 2927 (91.90%) and 258 (8.10%) had laminectomy with fusion and laminoplasty, respectively. Laminoplasty patients had significantly lower complication rates during index hospitalization (5.81 versus 9.62%, adjusted odds ratio [aOR]: 0.556, 95% confidence interval [CI]: 0.418–0.740, p < 0.0002), during 30 day (6.87 versus 11.12%, aOR: 0.568, 95% CI: 0.436–0.740, p < 0.0002) and 90 day (7.61 versus 11.78%, aOR: 0.593, 95% CI: 0.460–0.764, p < 0.0002) postoperative periods. They also had lower costs (United States dollars) during index hospitalization ($26,129 versus $35,483, p < 0.0004), and overall during the 2 year postoperative period ($77,960 versus $106,453, p < 0.0001). Two year reoperation rates were similar between both groups (9.77% versus 7.36%, p = 0.20). Our study suggests that cervical laminoplasty has significantly lower complication rates, similar long-term reoperation rates and lower healthcare resource utilization after 2 years than laminectomy with fusion.
    Journal of Clinical Neuroscience 12/2014; 22(3). · 1.32 Impact Factor
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    ABSTRACT: OBJECT Recent studies have reported that the local delivery of vancomycin powder is associated with a decrease in spinal surgical site infection. This retrospective cohort study compares posterior cervical fusion cases before and after the routine application of spinal vancomycin powder to evaluate the ability of local vancomycin powder to prevent deep wound infection after posterior cervical spinal fusion. METHODS Posterior cervical fusion spinal surgeries performed at a single institution were reviewed from January 2011 to July 2013. Each cohort's baseline characteristics, operative data, and rates of wound infection were compared. Associations between infection and vancomycin powder, with and without propensity score adjustment for risk factors, were determined using logistic regression. RESULTS A total of 289 patients (174 untreated and 115 treated with vancomycin powder) were included in the study. The cohorts were similar in terms of baseline and operative variables. No significant change in deep wound infection rate was seen between the control group (6.9%) and intervention group (5.2%, p = 0.563). Logistic regression, with and without propensity score adjustment, demonstrated that the use of vancomycin powder did not impact the development of surgical site infection (OR 0.743 [95% CI 0.270-2.04], p = 0.564) and (OR 0.583 [95% CI 0.198-1.718], p = 0.328), respectively. CONCLUSIONS Within the context of an ongoing debate on the effectiveness of locally administered vancomycin powder, the authors found no significant difference in the incidence of deep wound infection rates after posterior cervical fusion surgery with routine use of locally applied vancomycin powder. Future prospective randomized series are needed to corroborate these results.
    Journal of Neurosurgery Spine 11/2014; · 2.36 Impact Factor
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    ABSTRACT: Retrospective propensity score-matched cohort analysis of the Thomson Reuters MarketScan database.
    Asian spine journal 10/2014; 8(5):605-14.
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    ABSTRACT: Deep brain stimulation (DBS) is a well-established modality for the treatment of advanced Parkinson disease (PD). Recent studies have found DBS plus best medical therapy to be superior to best medical therapy alone for patients with PD and early motor complications. Although no specific age cutoff has been defined, most clinical studies have excluded patients older than 75 years of age. We hypothesize that increasing age would be associated with an increased number of postoperative complications.
    JAMA Neurology 08/2014; 71(10). · 7.01 Impact Factor
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    ABSTRACT: The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.
    Neuromodulation 08/2014; 17(6):515-550. · 1.79 Impact Factor
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    ABSTRACT: IntroductionThe International Neuromodulation Society (INS) has identified a need for evaluation and analysis of the practice of neurostimulation of the brain and extracranial nerves of the head to treat chronic pain.Methods The INS board of directors chose an expert panel, the Neuromodulation Appropriateness Consensus Committee (NACC), to evaluate the peer-reviewed literature, current research, and clinical experience and to give guidance for the appropriate use of these methods. The literature searches involved key word searches in PubMed, EMBASE, and Google Scholar dated 1970–2013, which were graded and evaluated by the authors.ResultsThe NACC found that evidence supports extracranial stimulation for facial pain, migraine, and scalp pain but is limited for intracranial neuromodulation. High cervical spinal cord stimulation is an evolving option for facial pain. Intracranial neurostimulation may be an excellent option to treat diseases of the nervous system, such as tremor and Parkinson's disease, and in the future, potentially Alzheimer's disease and traumatic brain injury, but current use of intracranial stimulation for pain should be seen as investigational.Conclusions The NACC concludes that extracranial nerve stimulation should be considered in the algorithmic treatment of migraine and other disorders of the head. We should strive to perfect targets outside the cranium when treating pain, if at all possible.
    Neuromodulation 08/2014; 17(6). · 1.79 Impact Factor
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    ABSTRACT: Object The Accreditation Council for Graduate Medical Education (ACGME) implemented resident duty-hour restrictions on July 1, 2003, in concern for patient and resident safety. Whereas studies have shown that duty-hour restrictions have increased resident quality of life, there have been mixed results with respect to patient outcomes. In this study, the authors have evaluated the effect of duty-hour restrictions on morbidity, mortality, length of stay (LOS), and charges in patients who underwent spine surgery. Methods The Nationwide Inpatient Sample was used to evaluate the effect of duty-hour restrictions on complications, mortality, LOS, and charges by comparing the prereform (2000-2002) and postreform (2005-2008) periods. Outcomes were compared between nonteaching and teaching hospitals using a difference-in-differences (DID) method. Results A total of 693,058 patients were included in the study. The overall complication rate was 8.6%, with patients in the postreform era having a significantly higher rate than those in the pre-duty-hour restriction era (8.7% vs 8.4%, p < 0.0001). Examination of hospital teaching status revealed complication rates to decrease in nonteaching hospitals (8.2% vs 7.6%, p < 0.0001) while increasing in teaching institutions (8.6% vs 9.6%, p < 0.0001) in the duty-hour reform era. The DID analysis to compare the magnitude in change between teaching and nonteaching institutions revealed that teaching institutions to had a significantly greater increase in complications during the postreform era (p = 0.0002). The overall mortality rate was 0.37%, with no significant difference between the pre- and post-duty-hour eras (0.39% vs 0.36%, p = 0.12). However, the mortality rate significantly decreased in nonteaching hospitals in the postreform era (0.30% vs 0.23%, p = 0.0008), while remaining the same in teaching institutions (0.46% vs 0.46%, p = 0.75). The DID analysis to compare the changes in mortality between groups revealed that the difference between the effects approached significance (p = 0.069). The mean LOS for all patients was 4.2 days, with hospital stay decreasing in nonteaching hospitals (3.7 vs 3.5 days, p < 0.0001) while significantly increasing in teaching institutions (4.7 vs 4.8 days, p < 0.0001). The DID analysis did not demonstrate the magnitude of change for each group to differ significantly (p = 0.26). Total patient charges were seen to rise significantly in the post-duty-hour reform era, increasing from $40,000 in the prereform era to $69,000 in the postreform era. The DID analysis did not reveal a significant difference between the changes in charges between teaching and nonteaching hospitals (p = 0.55). Conclusions The implementation of duty-hour restrictions was associated with an increased risk of postoperative complications for patients undergoing spine surgery. Therefore, contrary to its intended purpose, duty-hour reform may have resulted in worse patient outcomes. Additional studies are needed to evaluate strategies to mitigate these effects and assist in the development of future health care policy.
    Journal of Neurosurgery Spine 07/2014; · 2.36 Impact Factor
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    ABSTRACT: Object On July 1, 2003, the Accreditation Council for Graduate Medical Education (ACGME) implemented duty-hour restrictions for resident physicians due to concerns for patient and resident safety. Though duty-hour restrictions have increased resident quality of life, studies have shown mixed results with respect to patient outcomes. In this study, the authors have evaluated the effect of duty-hour restrictions on morbidity, mortality, length of stay, and charges in patients who underwent brain tumor and cerebrovascular procedures. Methods The Nationwide Inpatient Sample was used to evaluate the effect of duty-hour restrictions on complications, mortality, length of stay, and charges by comparing the pre-reform (2000-2002) and post-reform (2005-2008) periods. Outcomes were compared between nonteaching and teaching hospitals using a difference-in-differences (DID) method. Results A total of 90,648 patients were included in the analysis. The overall complication rate was 11.7%, with the rates not significantly differing between the pre- and post-duty hour eras (p = 0.26). Examination of hospital teaching status revealed that complication rates decreased in nonteaching hospitals (12.1% vs 10.4%, p = 0.0004) and remained stable in teaching institutions (11.8% vs 11.9%, p = 0.73) in the post-reform era. Multivariate analysis demonstrated a significantly higher complication risk in teaching institutions (OR 1.33 [95% CI 1.11-1.59], p = 0.0022), with no significant change in nonteaching hospitals (OR 1.11 [95% CI 0.91-1.37], p = 0.31). A DID analysis to compare the magnitude in change between teaching and nonteaching institutions revealed that teaching hospitals had a significantly greater increase in complications during the post-reform era than nonteaching hospitals (p = 0.040). The overall mortality rate was 3.0%, with a significant decrease occurring in the post-reform era in both nonteaching (5.0% vs 3.2%, p < 0.0001) and teaching (3.2% vs 2.3%, p < 0.0001) hospitals. DID analysis to compare the changes in mortality between groups did not reveal a significant difference (p = 0.40). The mean length of stay for all patients was 8.7 days, with hospital stay decreasing from 9.2 days to 8.3 days in the post-reform era (p < 0.0001). The DID analysis revealed a greater length of stay decrease in nonteaching hospitals than teaching institutions, which approached significance (p = 0.055). Patient charges significantly increased in the post-reform era for all patients, increasing from $70,900 to $96,100 (p < 0.0001). The DID analysis did not reveal a significant difference between the changes in charges between teaching and nonteaching hospitals (p = 0.17). Conclusions The implementation of duty-hour restrictions correlated with an increased risk of postoperative complications for patients undergoing brain tumor and cerebrovascular neurosurgical procedures. Duty-hour reform may therefore be associated with worse patient outcomes, contrary to its intended purpose. Due to the critical condition of many neurosurgical patients, this patient population is most sensitive and likely to be negatively affected by proposed future increased restrictions.
    Journal of Neurosurgery 06/2014; · 3.23 Impact Factor
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    ABSTRACT: Conversion rates from trial leads to permanent spinal cord stimulation (SCS) systems have recently come under scrutiny. Our goal was to examine the rate of conversion from trial lead to permanent system placement as well as identify factors associated with successful SCS conversion.
    Neuromodulation 06/2014; · 1.79 Impact Factor
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    ABSTRACT: Study Design. Retrospective cohort study.Objective. To investigate the association between preoperative baseline serum albumin and postoperative surgical complication.Summary of Background Data. The prevalence of malnutrition in the hospitalized patient population has only been recently recognized. Preoperative hypoalbuminemia (serum albumin < 3.5 g/dL) has been shown to be associated with increased morbidity and mortality rates. The prognostic implications and significance of hypoalbuminemia after spine fusion surgery remain unknown. In this study, we assess the predictive value of preoperative nutritional status (serum albumin level) on postoperative complication rates.Methods. The medical records of 136 consecutive patients undergoing spine fusion at our institution were reviewed. Preoperative serum albumin level was assessed on all patients and used to quantify nutritional status. Albumin less than 3.5 g/dL was recognized as hypoalbuminemia (malnourished). Patient demographics, comorbidities, and postoperative complication rates were collected. Patients were also stratified into two groups based on their etiology, namely elective degenerative/deformity versus non-elective cases. The association between preoperative serum albumin level and postoperative complication was assessed via logistic regression analysis.Results. Overall, 40 (29.4%) patients experience at least one postoperative complication. Patients undergoing elective surgery had more complications based on preoperative albumin levels (malnourished: 35.7% vs. nourished: 11.7%, p = 0.03), whereas those undergoing non-elective surgery had similar complication rates (malnourished: 46.5% vs. nourished: 42.1%, p = 0.75). For patients undergoing elective spinal surgery, logistic regression with and without propensity score adjustment for risk factors, demonstrated that preoperative serum albumin level was a significant predictor of postoperative complications (OR: 4.21, CI: 95% (1.09, 16.19), p = 0.04) and (OR: 4.54, CI: 95% (1.17, 19.32), p = 0.04), respectively.Conclusion. Preoperative hypoalbuminemia is an independent risk factor for postoperative complications following elective spine surgery for degenerative and deformity causes, and should be used more frequently as a prognostic tool to detect malnutrition and risk of adverse surgical outcomes.
    Spine 05/2014; · 2.45 Impact Factor
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    ABSTRACT: Study Design. Retrospective, observational.Objective. To simulate what episodes-of-care in spinal surgery might look like in a bundled payment system and to evaluate the associated costs and characteristics.Summary of Background Data. Episode-based payment bundling has received considerable attention as a potential method to help curb the rise in healthcare spending and is being investigated as a new payment model as part of the Affordable Care Act. While earlier studies investigated bundled payments in a number of surgical settings, very few focused on spine surgery specifically.Methods. We analyzed data from MarketScan. Patients were included in the study if they underwent cervical or lumbar spinal surgery in 2000-2009, had at least 2 years pre-operative and 90 days post-operative follow-up data. Patients were grouped based on their Diagnosis Related Group (DRG) and then tracked in simulated episodes-of-care/payment bundles that lasted for the duration of 30, 60, and 90 days following the discharge from the index-surgical hospitalization. Total costs associated with each episode-of-care duration were measured and characterized.Results. A total of 196,918 patients met our inclusion criteria. Significant variation existed between DRGs, ranging from $11,180 (30-day bundle, DRG 491) to $107,642 (30-day bundle, DRG). There were significant cost variations within each individual DRG. Post-discharge care accounted for a relatively small portion of overall bundle costs (range 4-8% in 90-day bundles). Total bundle costs remained relatively flat as bundle-length increased (total average cost of 30-day: $33,522 vs. $35,165 for 90-day). Payments to hospitals accounted for the largest portion of bundle costs (76%)Conclusion. There exists significant variation in total healthcare costs for spinal surgery patients, even within a given DRG. Better characterization of impacts of a bundled payment system in spine surgery is important for understanding the costs of index procedure hospital, physician services and post-operative care on potential future healthcare policy decision making.
    Spine 05/2014; · 2.45 Impact Factor
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    ABSTRACT: Study Design. Retrospective cohort analysisObjective. To examine the complications, reoperation rates, and resource use following each of the surgical approaches for the treatment of spinal stenosis.Summary of Background Data. There are no uniform guidelines for which procedure (decompression, decompression with instrumentation, or decompression with non-instrumented fusion) to perform for the treatment of spinal stenosis. With no clear evidence for increased efficacy, the rate of instrumented fusions is rising.Methods. We performed a retrospective cohort analysis of patients who underwent spinal stenosis surgery between 2002 and 2009 in the United States. Patients included (n = 12,657) were diagnosed with spinal stenosis without concurrent spondylolisthesis and had at least 2 years of pre-operative enrollment. A total of 2,385 decompression only and 620 fusion patients had follow-up data for 5 years or more.Results. Complication rates during the initial procedure hospitalization and at 90 days were significantly higher for those who underwent laminectomy with fusion compared to laminectomy alone, with reoperation rates not differing significantly between these groups. Long-term (≥5 years) reoperation rates were similar for those undergoing decompression alone vs. decompression with fusion (17.3% vs 16.0%, p = 0.44). Those with instrumented fusions had a slightly higher rate of reoperation compared to patients with non-instrumented fusions (17.4% vs. 12.2%, p = 0.11) at ≥5 years. The total cost including initial procedure and hospital, outpatient, emergency room, and medication charges at 5 years was similar for those who received decompression alone and fusion. The long-term costs for instrumented and non-instrumented fusions were also similar, totaling $107,056 and $100,471, respectively.Conclusions. For patients with spinal stenosis, if fusion is warranted, use of arthrodesis without instrumentation is associated with decreased costs with similar long-term complication and reoperation rates.
    Spine 04/2014; · 2.45 Impact Factor
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    ABSTRACT: Study Design. Retrospective review of a consecutive series of patients with radiologic evidence of spondylolisthesis.Objective. To establish the incidence and characteristics of spontaneous spinal arthrodesis (SSA) in the setting of lower lumbar spondylolisthesis.Summary of Background Data. Spontaneous spinal arthrodesis (SSA) of lumbar spondylolisthesis is a finding that is not discussed in the literature outside of isolated case reports. Identifying SSA may impact the surgical plan as fused patients may not require instrumentation and would require more work to reduce the spondylolisthesis.Methods. We reviewed a consecutive series of 1490 lumbar computed tomography scans from the year 2010 for radiologic evidence of spondylolisthesis at either L4-L5 or L5-S1. Patients were excluded if they had undergone previous lumbar surgery. Scans were assessed for the presence of spontaneous fusion based on the following criteria: 1) A solid bridging anterior or posterior vertebral body osteophyte, 2) Contiguous bone formation from one vertebral body to another, or 3) Contiguous bone across the facet joints bilaterally. Patients were characterized by demographic variables, radiologic characteristics including type of spondylolisthesis, and presenting symptomology. Differences between fused and non-fused patients were compared with univariate analysis.Results. A total of 86 separate instances of spondylolisthesis were identified, of which 18 (20.9%) had radiologic evidence of spontaneous fusion. The most common site of fusion was in the bilateral facets, followed by directly in the intervertebral disc space, and bridging osteophytes adjoining the vertebral bodies. There were significant differences between fused and non-fused patients in terms of average age (fused: 74.3 ± 10.7 years vs. non-fused: 63.3 ± 18.6 years, p = 0.019), gender (fused: 88.9% vs. non-fused: 57.4%, p = 0.013), and rate of pars defects (fused: 11.1% vs. non-fused: 35.3%, p = 0.047).Conclusions. In this study, 20.9% of patients with lumbar spondylolisthesis have radiologic signs of spontaneous fusion. Further work is needed to better characterize the natural history and clinical-radiological correlation of spontaneous fusion in spondylolisthesis.
    Spine 01/2014; · 2.45 Impact Factor
  • Article: In reply.
    Ranjith Babu, Ali R Zomorodi, Shivanand P Lad
    Neurosurgery 01/2014; 74(1):E146-7. · 3.03 Impact Factor
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    ABSTRACT: Postoperative radiotherapy (RT) is utilized routinely in the management of anaplastic World Health Organization Grade III gliomas (AG), including anaplastic astrocytoma (AA) and anaplastic oligodendroglioma (AO). However, the optimal role of RT in elderly AG patients remains controversial. We evaluated the effectiveness of RT in elderly AG patients using a national cancer registry. The USA Surveillance, Epidemiology, and End Results database (1990-2008) was used to query patients over 70years of age with AA or AO. Independent predictors of overall survival were determined using a multivariate Cox proportional hazards model. Among 390 elderly patients with AG, 333 (85%) had AA and 57 (15%) had AO. Approximately two-thirds of AA patients (64%) and AO patients (65%) received RT. Most AO patients (58%) and many AA patients (41%) underwent surgical resection; the remainder had biopsy. The median overall survival for all patients who underwent RT was 6months (95% confidence interval [CI], 5-7months) versus 2months (95% CI 1-6) in patients who did not have RT. Patients who had gross total resection (GTR) plus RT had a median overall survival of 11 months (95% CI 7-14). Multivariate analysis for all patients showed that undergoing RT was significantly associated with improved survival (hazard ratio [HR] 0.52, p<.0001). AA tumor type (HR 1.37, p=.03) was associated with worse survival than AO tumor type; female sex (HR 0.59, p<.0001) and being married (HR 0.66, p=.002) significantly improved survival. Patients that underwent GTR had a significant reduction in the hazards of mortality compared to biopsy (HR 0.72, p=.04). Elderly AG patients undergoing RT had better overall survival compared to patients who did not receive RT. Treatment strategies involving maximal safe resection plus RT should be considered in the optimal management of AG in elderly patients.
    Journal of Clinical Neuroscience 12/2013; · 1.32 Impact Factor
  • Journal of Neurosurgery 11/2013; · 3.15 Impact Factor
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    ABSTRACT: Surgery remains the mainstay for management of lumbar spondylolisthesis and is considered an effective therapeutic modality following unsuccessful nonoperative treatment. Surgical procedures include decompression, decompression with instrumented arthrodesis, and decompression with noninstrumented arthrodesis. The purpose of this study was to examine the complications, reoperation rates, and health-care costs associated with each of these procedures. The MarketScan database was utilized to identify 16,556 patients with a primary diagnosis of lumbar spondylolisthesis who underwent surgical treatment from 2000 to 2009. Outcomes were evaluated in propensity score-matched cohorts, with complication rates analyzed with the chi-square test, reoperation rates analyzed using the Mantel-Haenszel test, and health-care resource use analyzed using the Wilcoxon signed-rank test. Complication rates were significantly higher in patients who underwent arthrodesis compared with those who had decompression alone during the initial hospitalization (8.3% versus 4.8%; p < 0.0001) and at the time of the ninety-day follow-up (9.6% versus 5.5%; p < 0.0001). Complication rates were similar for those who received instrumented and noninstrumented arthrodesis. Patients who underwent decompression alone had higher reoperation rates at two years or more than those who received arthrodesis (15.7% versus 11.9%; p = 0.034). Patients with instrumented arthrodesis trended to have higher reoperation rates than those without instrumentation at five years or more (18.4% versus 10.6%; p = 0.063). Initial hospital costs and two-year and five-year overall costs (in 2009 U.S. dollars) were higher for patients managed with arthrodesis than for those who had decompression only ($102,906 versus $89,337; p = 0.0018). Also, patients who received instrumentation had higher hospitalization costs than those without instrumentation ($39,997 versus $27,309; p = 0.023) and higher overall costs at two years ($73,482 versus $60,394; p < 0.0001), although the difference was not significant at five years (p = 0.29). Patients with lumbar spondylolisthesis who underwent decompressive laminectomy and spinal arthrodesis had lower reoperation rates but higher overall costs than patients treated with laminectomy alone. Noninstrumented arthrodesis was also associated with lower long-term reoperation rates and health-care costs compared with instrumented arthrodesis. The long-term outcomes and costs of these procedures should be evaluated in conjunction with clinical efficacy to ensure the most cost-effective treatment is utilized. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 11/2013; 95(21):e1621-10. · 4.31 Impact Factor

Publication Stats

772 Citations
211.64 Total Impact Points


  • 2011–2015
    • Duke University Medical Center
      • Division of Neurosurgery
      Durham, North Carolina, United States
  • 2012–2013
    • Los Angeles Neurosurgical Institute
      Los Angeles, California, United States
    • University of Louisville
      Louisville, Kentucky, United States
    • Duke University
      Durham, North Carolina, United States
  • 2006–2012
    • Stanford University
      • Department of Neurosurgery
      Stanford, CA, United States
  • 2010
    • VA Palo Alto Health Care System
      Palo Alto, California, United States
  • 2007–2008
    • Stanford Medicine
      • Department of Neurosurgery
      Stanford, California, United States