Chirag G. Patil

Epidemiology and the Global Burden of Stroke

OBJECTIVE Stroke remains one of the most devastating of all neurological diseases, often causing death or gross physical impairment or disability. As numerous countries throughout the world undergo the epidemiological transition of diseases, trends in the prevalence of stroke have dramatically changed. METHODS All major international epidemiological articles published during the past 20 years addressing the global burden of stroke were reviewed. A focus was placed upon better defining current and future trends in surveillance, incidence, burden of disease, mortality, and costs associated with stroke internationally. RESULTS Despite the fact that various surveillance systems are used to identify stroke and its sequela around the world, it is clear that stroke remains one of the top causes of mortality and disability-adjusted life-years (DALYs) lost globally. Concerning trends include the increase of stroke mortality and lost DALYs in low- and middle-income countries. The global economic impact of stroke may be dire if effective preventive measures are not implemented to help decrease the burden of this disease. CONCLUSION The global burden of stroke is high, inclusive of increasing incidence, mortality, DALYs, and economic impact, particularly in low- and middle-income countries. The implementation of better surveillance systems and prevention programs are needed to help track current trends as well as to curb the projected exponential increase in stroke worldwide.

Risk Factors for Postoperative Spinal Wound Infections After Spinal Decompression and Fusion Surgeries

Study Design. This is a multivariate analysis of a prospectively collected database. Objective. To determine preoperative, intraoperative, and patient characteristics that contribute to an increased risk of postoperative wound infection in patients undergoing spinal surgery. Summary of Background Data. Current literature sites a postoperative infection rate of approximately 4%; however, few have completed multivariate analysis to determine factors which contribute to risk of infection. Methods. Our study identified patients who underwent a spinal decompression and fusion between 1997 and 2006 from the Veterans Affairs’ National Surgical Quality Improvement Program database. Multivariate logistic regression analysis was used to determine the effect of various preoperative variables on postoperative infection. Results. Data on 24,774 patients were analyzed. Wound infection was present in 752 (3.04%) patients, 287 (1.16%) deep, and 468 (1.89%) superficial. Postoperative infection was associated with longer hospital stay (7.12 vs. 4.20 days), higher 30-day mortality (1.06% vs. 0.5%), higher complication rates (1.24% vs. 0.05%), and higher return to the operating room rates (37% vs. 2.45%). Multivariate logistic regression identified insulin dependent diabetes (odds ratios [OR] = 1.50), current smoking (OR = 1.19) ASA class of 3 (OR = 1.45) or 4 to 5 (OR = 1.66), weight loss (OR = 2.14), dependent functional status (1.36) preoperative HCT <36 (1.37), disseminated cancer (1.83), fusion (OR = 1.24) and an operative duration of 3 to 6 hours (OR = 1.33) or >6 hours (OR = 1.40) as statistically significant predictors of postoperative infection. Conclusion. Using multivariate analysis of a large prospectively collected data from the National Surgical Quality Improvement Program database, we identified the most important risk factors for increased postoperative spinal wound infection. We have demonstrated the high mortality, morbidity, and hospitalization costs associated with postoperative spinal wound infections. The information provided should help alert clinicians to presence of these risks factors and the likelihood of higher postoperative infections and morbidity in spinal surgery patients.

Delayed radiation-induced myelopathy after spinal radiosurgery.

OBJECTIVESpinal cord injury is arguably the most feared complication in radiotherapy and has historically limited the aggressiveness of spinal tumor treatment. We report a case series of 6 patients treated with radiosurgery who developed delayed myelopathy. METHODSBetween 1996 and 2005, 1075 patients with benign or malignant spinal tumors were treated by CyberKnife (Accuray, Inc., Sunnyvale, CA) robotic radiosurgery at Stanford University Medical Center and the University of Pittsburgh Medical Center. Patients were followed prospectively with clinical and radiographic assessments at 1- to 6-month intervals. A retrospective review identified patients who developed delayed radiation-induced myelopathy. Six patients (5 women, 1 man) with a mean age of 48 years (range, 25–61 years) developed delayed myelopathy at a mean of 6.3 months (range, 2–9 months) after spinal radiosurgery. Three tumors were metastatic; 3 were benign. The metastases were in the upper to midthoracic spine, whereas the benign tumors were partially in the cervical region. Three cases involved previous radiation therapy. RESULTSDose volume histograms were generated for target and critical structures. Clinical and dosimetric factors were analyzed for factors predictive of spinal cord injury. Specific dosimetric factors contributing to this complication could not be identified, but one-half of the patients with myelopathy received spinal cord biological equivalent doses exceeding 8 Gy. CONCLUSIONDelayed myelopathy after radiosurgery is uncommon with the dose schedules used in this case series. Radiation injury to the spinal cord occurred over a spectrum of dose parameters that prevented identification of specific dosimetric factors contributing to this complication. Primarily, biological equivalent dose estimates were not usable for defining spinal cord tolerance to hypofractionated dose schedules. We recommend limiting the volume of spinal cord treated above an 8-Gy equivalent dose, because half of the complications occurred beyond this level.OBJECTIVE Spinal cord injury is arguably the most feared complication in radiotherapy and has historically limited the aggressiveness of spinal tumor treatment. We report a case series of 6 patients treated with radiosurgery who developed delayed myelopathy. METHODS Between 1996 and 2005, 1075 patients with benign or malignant spinal tumors were treated by CyberKnife (Accuray, Inc., Sunnyvale, CA) robotic radiosurgery at Stanford University Medical Center and the University of Pittsburgh Medical Center. Patients were followed prospectively with clinical and radiographic assessments at 1- to 6-month intervals. A retrospective review identified patients who developed delayed radiation-induced myelopathy. Six patients (5 women, 1 man) with a mean age of 48 years (range, 25-61 years) developed delayed myelopathy at a mean of 6.3 months (range, 2-9 months) after spinal radiosurgery. Three tumors were metastatic; 3 were benign. The metastases were in the upper to midthoracic spine, whereas the benign tumors were partially in the cervical region. Three cases involved previous radiation therapy. RESULTS Dose volume histograms were generated for target and critical structures. Clinical and dosimetric factors were analyzed for factors predictive of spinal cord injury. Specific dosimetric factors contributing to this complication could not be identified, but one-half of the patients with myelopathy received spinal cord biological equivalent doses exceeding 8 Gy. CONCLUSION Delayed myelopathy after radiosurgery is uncommon with the dose schedules used in this case series. Radiation injury to the spinal cord occurred over a spectrum of dose parameters that prevented identification of specific dosimetric factors contributing to this complication. Primarily, biological equivalent dose estimates were not usable for defining spinal cord tolerance to hypofractionated dose schedules. We recommend limiting the volume of spinal cord treated above an 8-Gy equivalent dose, because half of the complications occurred beyond this level.

National complication rates and disposition after posterior lumbar fusion for acquired spondylolisthesis.

Study Design. Database study using Nationwide Inpatient Sample (NIS) administrative data from 1993 to 2002. Objective. To determine rates of in-hospital complications and complex disposition for patients undergoing posterior lumbar fusion for degenerative spondylolisthesis, and the association of demographic factors. Summary of Background Data. Spondylolisthesis affects primarily elderly populations. Recent data suggests a benefit of surgical treatment for acquired lumbar spondylolisthesis. However, the risks of these procedures, and the impact of patient demographics on risk, have not been nationally quantified. Methods. Data from 66,601 patients in the NIS (1993–2002) with diagnostic and procedure codes specifying posterior lumbar fusion for acquired spondylolisthesis were included. Patients were grouped by age, sex, race, number of comorbidities, hospital size, and time period of procedure. Multivariate analysis correlated patient and hospital characteristics with complex disposition and complications. Results. Mortality rate was 0.15%. Eleven percent of patients had one or more in-hospital complications; overall complication rate was 13 per 100 operations. Hematoma/seroma (5.4 per 100) was the most common complication, followed by pulmonary (2.6), renal (1.8), and cardiac (1.2) complications. Infection and neurologic injury occurred in <1% of patients. Older patients and those with a number of comorbidities had greater rates of in-hospital complication and complex disposition. Compared to those aged 45 to 64, patients aged 65 to 84 were almost 70% more likely to have complications (OR: 1.67) and 5 times as likely to have complex disposition (OR: 5.84). Having 3 or greater comorbidities, compared to no comorbidities, was also associated with increased risk of complication (OR: 1.6) and complex disposition (OR: 2.3). Conclusion. Posterior lumbar fusion for acquired lumbar spondylolisthesis is safe. However, age and comorbidity independently increase in-hospital complications and complex disposition. These data may improve national estimates of surgical risk, patient selection, informed consent, and cost-efficacy analysis for posterior lumbar fusion operations for acquired spondylolisthesis.

Cervical spondylotic myelopathy: complications and outcomes after spinal fusion.

OBJECTIVE There is little information about in-hospital complication rates, adverse outcomes, and mortality after spinal fusion for cervical spondylotic myelopathy (CSM). The aim of this study was to report inpatient mortality, complications, and outcomes on a national level. METHODS We used the National Inpatient Sample to identify 58,115 admissions of patients with CSM who underwent spinal fusion in the United States from 1993 to 2002. Multivariate analysis was performed to analyze the effects of patient and hospital characteristics on outcomes such as mortality, complications, discharge disposition, and length of stay. RESULTS A total of 58,115 patients with CSM underwent spinal fusion with an average mortality rate of 0.6%, a complication rate of 13.4%, and a mean length of stay of 4 days. Pulmonary (3.6%) and postoperative hemorrhages or hematomas (2.3%) were the most common complications reported. One postoperative complication led to a 4-day increase in mean length of stay, increased the mortality rate 20-fold, and added more than

Visual Loss After Spine Surgery : A Population-Based Study

10,000 to hospital charges. Multivariate analysis identified age, comorbidity, and admission type as the main predictors of mortality, complication rate, and adverse outcome. Patients aged > or =85 or 65 to 84 years had respective 44- and 14-fold increases in mortality, compared with patients in the 18- to 44-year age group. Patients older than 84 years had a 40-fold increase in adverse outcomes and a 5-fold likelihood of medical complications. Patients with three or more comorbidities had an increased risk of medical complications (odds ratio [OR], 1.98), adverse discharge (OR, 2.17), and in-hospital mortality (OR, 2.36). Elective admissions were associated with much lower rates of mortality (OR, 0.28), complication (OR, 0.68), and adverse outcome (OR, 0.26). Complications were greater for posterior fusion (16.4%) versus anterior fusion (11.9%) procedures. Anterior fusions were associated with a greater incidence of dysphagia (3%) and hoarseness (0.21%). Cervical spondylosis patients who presented without myelopathy had a much lower incidence of complications (6.3%). CONCLUSIONS We provide a national estimate of inpatient complications and outcomes after spinal fusion for CSM patients in the United States. We demonstrate the impacts of age, complications, and medical comorbidities on the outcome of surgery for patients with this common disorder. We provide complication rates stratified by age and medical comorbidities for elderly patients who present with CSM who need spinal fusion.

Moyamoya disease in pediatric patients: outcomes of neurosurgical interventions

Study Design. Retrospective cohort study using National inpatient sample administrative data. Objective. To determine national estimates of visual impairment and ischemic optic neuropathy after spine surgery. Summary of Background Data. Loss of vision after spine surgery is rare but has devastating complications that has gained increasing recognition in the recent literature. National population-based studies of visual complications after spine surgery are lacking. Methods. All patients from 1993 to 2002 who underwent spine surgery (Clinical Classifications software procedure code: 3, 158) and who had ischemic optic neuropathy (ION) (ICD9-CM code 377.41), central retinal artery occlusion (CRAO) (ICD9-CM code 362.31) or non-ION, non-CRAO perioperative visual impairment (ICD9-CM codes: 369, 368.4, 368.8–9368.11–13) were included. Univariate and multivariate analysis were performed to identify potential risk factors. Results. The overall incidence of visual disturbance after spine surgery was 0.094%. Spine surgery for scoliosis correction and posterior lumbar fusion had the highest rates of postoperative visual loss of 0.28% and 0.14% respectively. Pediatric patients (<18 years) were 5.8 times and elderly patients (>84 years) were 3.2 times more likely than, patients 18 to 44 years of age to develop non-ION, non-CRAO visual loss after spine surgery. Patients with peripheral vascular disease (OR = 2.0), hypertension (OR = 1.3), and those who received blood transfusion (OR = 2.2) were more likely to develop non-ION, non-CRAO vision loss after spine surgery. Ischemic optic neuropathy was present in 0.006% of patients. Hypotension (OR = 10.1), peripheral vascular disease (OR = 6.3) and anemia (OR = 5.9) were the strongest risk factors identified for the development of ION. Conclusion. We used multivariate analysis to identify significant risk factors for visual loss after spine surgery. National population-based estimate of visual impairment after spine surgery confirms that ophthalmic complications after spine surgery are rare. Since visual loss may be reversible in the early stages, awareness, evaluation and prompt management of this rare but potentially devastating complication is critical.

Effects of age and comorbidities on complication rates and adverse outcomes after lumbar laminectomy in elderly patients.

Neurosurgical interventions for moyamoya disease (MMD) in pediatric patients include direct, indirect, and combined revascularization procedures. Each technique has shown efficacy in the treatment of pediatric MMD; however, no single study has demonstrated the superiority of one technique over another. In this review, the authors explore the various studies focused on the use of these techniques for MMD in the pediatric population. They summarize the results of each study to clearly depict the clinical outcomes achieved at each institution that had utilized direct, indirect, or combined techniques. In certain studies, multiple techniques were used, and the clinical or radiological outcomes were compared accordingly. Direct techniques have been shown to aid a reduction in perioperative strokes and provide immediate revascularization to ischemic areas; however, these procedures are technically challenging, and not all pediatric patients are appropriate candidates. Indirect techniques have also shown efficacy in the pediatric population but may require a longer period for revascularization to occur and perfusion deficits to be reversed. The authors concluded that the clinical efficacy of one technique over another is still unclear, as most studies have had small populations and the same outcome measures have not been applied. Authors who compared direct and indirect techniques noted approximately equal clinical outcomes with differences in radiological findings. Additional, larger studies are needed to determine the advantages and disadvantages of the different techniques for the pediatric age group.

OUTCOMES AFTER REPEAT TRANSSPHENOIDAL SURGERY FOR RECURRENT CUSHING'S DISEASE

Study Design. This is a retrospective cohort study using the National Inpatient Sample database. Objective. The objective is to report mortality and complications after lumbar laminectomy in the elderly. Summary of Background Data.— As the population continues to age in the United States, it is important to consider the surgical complications and outcomes in the elderly. A review of the literature reveals controversy over the safety of lumbar laminectomy in the elderly and disagreement over estimates of risks in this population. Methods. Outcome measures were abstracted from the National Inpatient Sample. Multivariate analysis was performed to analyze the effect of patient and hospital characteristics on outcome measures. Results. A total of 471,215 patients underwent lumbar laminectomy without fusion for lumbar stenosis from 1993 to 2002. The in-hospital mortality rate was 0.17%, and the complication rate was 12.17%. Postoperative hemorrhage or hematoma (5.2%) and nonspecific renal complications (2.8%) were the most common complications. Complication and mortality rates increased with age and comorbidities with an 18.9% complication rate and 1.4% mortality rate in patients over the age of 85 with 3 or more comorbidities, 14.7% complication rate and 0.22% mortality rate in patients over 85 with no comorbidities, and only a 6% complication rate and 0.05% mortality rate in patient between 18 and 44 with no comorbidities. Multivariate analysis revealed increased odds of mortality with increasing number of comorbidities and complications in the greater than 85 year age group. Increasing age, number of comorbidities, complication rate, and female sex also increased the odds of discharge to institution other than home. Conclusion. Elderly patients with comorbidities are at a higher risk for complications and adverse outcome after lumbar spine surgery. The effects of age and comorbidities on patient outcomes have been quantified. This information is critical in counseling elderly patients about the risk of surgery in their age group.

National inpatient complications and outcomes after surgery for spinal metastasis from 1993–2002

OBJECTIVETo systematically analyze patient outcomes after repeat transsphenoidal (TS) surgery for recurrent Cushings disease. METHODSWe retrospectively reviewed records of all patients with recurrent Cushings disease who underwent repeat TS surgery for resection of a pituitary corticotroph adenoma at the University of Virginia Medical Center from 1992 to 2006. Remission at follow-up was defined as a normal postoperative 24-hour urine free cortisol, or continued need for glucocorticoid replacement after repeat TS surgery. Recurrence of the disease was defined as an elevated 24-hour urine free cortisol with clinical symptoms consistent with Cushings disease while not receiving glucocorticoid replacement. Multivariate logistic regression was performed to evaluate the effect of potential predictors on remission. Recurrence rates, subsequent treatments, and the final endocrine status of the patients are presented. RESULTSWe identified 36 patients who underwent repeat TS surgery for recurrent Cushings disease. The mean age of the patients was 40.3 years (range, 17.1–63.0 yr), and 26 were women. The median time to recurrence after initial successful TS surgery was 36 months (range, 4 mo–16 yr). Remission after repeat TS surgery was observed in 22 (61%) of the 36 patients. During the same time period, of the 338 patients who underwent first-time TS surgery for Cushings disease, remission was achieved in 289 (85.5%). The odds of failure (to achieve remission) for patients with repeat TS surgery for recurrent Cushings disease were 3.7 times that of patients undergoing first-time TS surgery (odds ratio, 3.7; 95% confidence interval, 1.8–7.8). Two of the 22 patients with successful repeat TS surgery had a second recurrence at 6 and 11 months, respectively. Complete biochemical and clinical remission after stereotactic radiosurgery, adrenalectomy, and ongoing ketoconazole therapy was achieved in 30 (83.3%) of the 36 patients, and active disease continued in 6 patients (16.7%). CONCLUSIONAlthough the success of repeat TS surgery for recurrence of Cushings disease is less than that of initial surgery, a second procedure offers a reasonable possibility of immediate remission. If the operation is not successful, other treatments, including pituitary radiation, medical therapy, and even bilateral adrenalectomy, are required.