Prognostic Factors and Treatment of Spinal Astrocytomas: A Multi-institutional Cohort Analysis.

STUDY DESIGN: Retrospective cohort analysis of patients with spinal astrocytoma from multi-institutional data and the literature. OBJECTIVE: To determine the prognostic factors, treatment, and survival of patients. SUMMARY OF BACKGROUND DATA: Our current understanding of the epidemiology, prognosis, and optimal treatment of spinal astrocytoma is limited. The literature is confined to case reports or small institutional case series. METHOD: Patient demographics, tumor characteristics, treatments, and outcomes were extracted. Univariate Kaplan-Meier survival analysis was performed to identify prognostic factors followed by multivariate Cox proportional hazard analysis. Wilcoxon signed-rank test was performed on pre- and postoperational functional status as measured by McCormick score. RESULTS: Ninety-four patients from four institutions and 339 patients from the literature were included. For the multi-institutional cohort, WHO grade IV tumors had shorter progression-free survival (PFS) than those of lower grades, whereas gross total resection (GTR) (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: 0.14-1.27, P = 0.124) trended toward longer PFS when compared to subtotal resection (STR). Age 18 years or older, paresthesia as a presenting symptom, and higher WHO grade were associated with shorter overall survival (OS), whereas thoracic tumor location when compared to cervical tumor location, biopsy when compared to STR, and radiotherapy (HR: 0.42, 95% CI: 0.20-0.88, P = 0.022) were associated with longer OS. For the literature cohort, GTR (HR 0.43, 95% CI: 0.24-0.77, P = 0.005) was associated with longer PFS when compared to STR, whereas higher WHO grade was associated with shorter PFS. Higher WHO grade and recurrence/progression were associated with shorter OS. Postoperative McCormick score was significantly higher than preoperative score (P < 0.001), but subgroup analysis of the change in McCormick score by extent of resection revealed no differences among groups (P = 0.551). CONCLUSION: In patients with spinal astrocytomas, GTR likely resulted in longer PFS when compared to STR. Adjuvant radiotherapy appears to be effective in improving survival outcomes for high-grade tumors. LEVEL OF EVIDENCE: 4.

Enhancing the role of private practitioners in tuberculosis prevention and care activities in India.

India accounts for the highest number of incident tuberculosis (TB) cases globally. Hence, to impact the TB incidence world over, there is an urgent need to address and accelerate TB control activities in the country. Nearly, half of the TB patients first seek TB care in private sector. However, the participation of private practitioners (PPs) has been patchy in TB prevention and care and distrust exists between public and private sector. PPs usually have varied diagnostic and treatment practices that are inadequate and amplify the risk of drug resistance. Hence, their regulation and involvement as key stakeholders are important in TB prevention and care in India if we are to achieve TB control at global level. However, there remain certain barriers and gaps, which are preventing their upscaling. The current paper aims to discuss the status of private sector involvement in TB prevention and care in India. The paper also discusses the strategies and initiatives taken by the government in this regard as evidence shows that the involvement of private sector in co-opting directly observed treatment short-course (DOTS) helps to enhance case finding and treatment outcomes; it improves the accessibility of quality TB care with greater geographic coverage. Besides public-private mix, DOTS has been found more cost-effective and reduces financial burden of patients. The paper also offers to present some more solutions both at policy and program level for upscaling the engagement of PPs in the national TB control program.

Management of Glioblastoma Multiforme in Elderly Patients: A Review of the Literature.

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, occurs most commonly in individuals older than 65 years of age, and is universally fatal. Increasing age compounds the poor prognosis of GBM, as elderly patients have markedly worse outcomes than younger patients. However, many of the studies previously investigating optimal treatment regimens exclude patients older than the age of 65 years and thus may not represent the best approaches to ensuring prolonged survival with preserved quality of life. This review aims to highlight the current literature on surgical and medical management, including our own experience, for GBM in the elderly patients, and to provide rational treatment approaches for a vulnerable, often-overlooked, patient population.

Comparing outcomes of early, late, and non-surgical management of intraspinal abscess.

Intraspinal abscesses (ISAs) are rare lesions that are often neurologically devastating. Current treatment paradigms vary widely including early surgical decompression, drainage, and systemic antibiotics, delayed surgery, and sole medical management. The National Inpatient Sample (NIS) database was queried for cases of ISA from 2003 to 2012. Early and late surgery were defined as occurring before or after 48h of admission. Outcome measures included mortality, incidence of major complications, length of stay (LOS), and inpatient costs. A total of 10,150 patients were included (6281 early surgery, 3167 delayed surgery, 702 medical management). Paralysis, the main comorbidity, was most associated with early surgery (p<0.0001). In multivariate analysis, the rates of postoperative infection and paraplegia were highest with early surgery (p<0.0001), but the incidence of sepsis was higher with delayed surgery (p<0.0001). Early surgery was least associated with in-hospital mortality (p=0.0212), sepsis (p<0.001), and had the shortest LOS (p<0.001). Charges were highest with delayed surgery, and least with medical management (p<0.001). Medical management was associated with lower rates of complications (p<0.001). This is the largest study of patients with ISAs ever performed. Our results suggest that patients with ISAs undergoing surgical management have better outcomes and lower costs when operated on within 48h of admission, emphasizing the importance of accurate and early diagnosis of ISA.

Glioblastoma in the elderly: the effect of aggressive and modern therapies on survival.

OBJECTIVE: The prognosis of elderly patients with glioblastoma (GBM) is universally poor. Currently, few studies have examined postoperative outcomes and the effects of various modern therapies such as bevacizumab on survival in this patient population. In this study, the authors evaluated the effects of various factors on overall survival in a cohort of elderly patients with newly diagnosed GBM. METHODS: A retrospective review was performed of elderly patients (≥ 65 years old) with newly diagnosed GBM treated between 2004 and 2010. Various characteristics were evaluated in univariate and multivariate stepwise models to examine their effects on complication risk and overall survival. RESULTS: A total of 120 patients were included in the study. The median age was 71 years, and sex was distributed evenly. Patients had a median Karnofsky Performance Scale (KPS) score of 80 and a median of 2 neurological symptoms on presentation. The majority (53.3%) of the patients did not have any comorbidities. Tumors most frequently (43.3%) involved the temporal lobe, followed by the parietal (35.8%), frontal (32.5%), and occipital (15.8%) regions. The majority (57.5%) of the tumors involved eloquent structures. The median tumor size was 4.3 cm. Every patient underwent resection, and 63.3% underwent gross-total resection (GTR). The vast majority (97.3%) of the patients received the postoperative standard of care consisting of radiotherapy with concurrent temozolomide. The majority (59.3%) of patients received additional agents, most commonly consisting of bevacizumab (38.9%). The median survival for all patients was 12.0 months; 26.7% of patients experienced long-term (≥ 2-year) survival. The extent of resection was seen to significantly affect overall survival; patients who underwent GTR had a median survival of 14.1 months, whereas those who underwent subtotal resection had a survival of 9.6 months (p = 0.038). Examination of chemotherapeutic effects revealed that the use of bevacizumab compared with no bevacizumab (20.1 vs 7.9 months, respectively; p < 0.0001) and irinotecan compared with no irinotecan (18.0 vs 9.7 months, respectively; p = 0.027) significantly improved survival. Multivariate stepwise analysis revealed that older age (hazard ratio [HR] 1.06 [95% CI1.02-1.10]; p = 0.0077), a higher KPS score (HR 0.97 [95% CI 0.95-0.99]; p = 0.0082), and the use of bevacizumab (HR 0.51 [95% CI 0.31-0.83]; p = 0.0067) to be significantly associated with survival. CONCLUSION: This study has demonstrated that GTR confers a modest survival benefit on elderly patients with GBM, suggesting that safe maximal resection is warranted. In addition, bevacizumab significantly increased the overall survival of these elderly patients with GBM; older age and preoperative KPS score also were significant prognostic factors. Although elderly patients with GBM have a poor prognosis, they may experience enhanced survival after the administration of the standard of care and the use of additional chemotherapeutics such as bevacizumab.

Radiation-induced malignant gliomas: a current review.

OBJECTIVE: Radiation-induced malignant gliomas (RIMGs) are known uncommon risks of brain irradiation. We describe 4 cases of RIMG that occurred at our institution and conduct the largest comprehensive review of the literature to characterize RIMGs better. METHODS: Patients were identified through the PubMed database. Pearson R linear correlation test was used to evaluate the correlation between radiotherapy (RT) dose and age and latency period. Student t test was used to evaluate differences between latency periods for original tumor lesions. A normalized biologic equivalent dose analysis was performed to indicate the minimum and maximum radiation threshold for neoplasia. A Kaplan-Meier analysis was used to illustrate the overall survival curves. RESULTS: The analysis included 172 cases from the PubMed database and 4 cases occurring at our institution. The median RT dose administered was 35.6 Gy, with the most common dosage ranges being 21-30 Gy (31%) and 41-50 Gy (21.5%). Median latency period was 9 years until diagnosis of RIMG, and RIMG occurred within 15 years in 82% of the patients. There was no correlation between the age of the patient at the time RT was administered (R(2) = 0.00081) or amount of RT (R(2) = 0.00005) and latency period for RIMG. The mean biologic equivalent dose for neoplasia of a RIMG was 63.3 Gy. The median survival of patients with RIMG improved over time (P = 0.004), with median survival of 9 months before 2007 and 11.5 months after 2007. CONCLUSIONS: The risk of RIMG appears to be the same for all age groups, histologies, and RT dosages. Although the risk is low, patients should be aware of RIMG as a possible complication of brain irradiation.

Morbidity, mortality, and health care costs for patients undergoing spine surgery following the ACGME resident duty-hour reform: Clinical article.

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.

Endovascular treatment of a spinal dural arteriovenous malformation (DAVF).

We present a case of a patient with rapid loss of motor strength in his lower extremities. He became bedridden with bowel and bladder incontinence, and developed saddle anesthesia. MRI of the lumbar spine showed edema in the conus medullaris and multiple flow voids within the spinal canal. A spinal angiogram showed a dorsal Type I spinal AVF. This was treated successfully with Onyx 18 (eV3, Irvine, CA). The patient showed rapid post-procedure improvement, and at discharge from the hospital to a rehabilitation center he was fully ambulatory. At 3-year follow-up, the patient was found to ambulate without difficulty. He also had improved saddle anesthesia, and he was voiding spontaneously. There was no evidence of flow voids on repeat MRI of the lumbar spine. The video can be found here: http://youtu.be/SDYNIGNQIW8 .

Transcirculation balloon-assisted stent-supported coil embolization of a basilar tip aneurysm.

We present the case of a balloon-assisted, stent-supported coil embolization of a basilar tip aneurysm. Initially, a balloon extending from the basilar artery into the right PCA was placed. However, even with a more proximal purchase, coils were found to impinge on the left PCA. Subsequently, a transcirculation approach was performed, where the left posterior communicating artery was utilized as a conduit for balloon support and the coils were embolized from the ipsilateral vertebral artery. However, after this transcirculation approach was completed, there was a coil tail extruding from the aneurysm. The balloon was then removed over an exchange wire and a horizontal stent advanced, spanning the entire neck of the aneurysm, eliminating the extruded coil. The video can be found here: http://youtu.be/bMbtZoPnYvo .

Worse outcomes for patients undergoing brain tumor and cerebrovascular procedures following the ACGME resident duty-hour restrictions.

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.

Spinal surgery: variations in health care costs and implications for episode-based bundled payments.

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 health care spending and is being investigated as a new payment model as part of the Affordable Care Act. Although 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 during 2000-2009, had at least 2-year preoperative and 90-day postoperative follow-up data. Patients were grouped on the basis of 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 after the discharge from the index-surgical hospitalization. The total cost associated with each episode-of-care duration was 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 456). There were significant cost variations within each individual DRG. Postdischarge 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 bundle: $33,522 vs. $35,165 for 90-day bundle). Payments to hospitals accounted for the largest portion of bundle costs (76%). CONCLUSION: There exists significant variation in total health care costs for patients who undergo spinal surgery, 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 postoperative care on potential future health care policy decision making. LEVEL OF EVIDENCE: N/A.

Malignant brainstem gliomas in adults: clinicopathological characteristics and prognostic factors.

Adult malignant brainstem gliomas (BSGs) are poorly characterized due to their relative rarity. We have examined histopathologically confirmed cases of adult malignant BSGs to better characterize the patient and tumor features and outcomes, including the natural history, presentation, imaging, molecular characteristics, prognostic factors, and appropriate treatments. A total of 34 patients were identified, consisting of 22 anaplastic astrocytomas (AAs) and 12 glioblastomas (GBMs). The overall median survival for all patients was 25.8 months, with patients having GBMs experiencing significantly worse survival (12.1 vs. 77.0 months, p = 0.0011). The majority of tumors revealed immunoreactivity for EGFR (93.3 %) and MGMT (64.7 %). Most tumors also exhibited chromosomal abnormalities affecting the loci of epidermal growth factor receptor (92.9 %), MET (100 %), PTEN (61.5 %), and 9p21 (80 %). AAs more commonly appeared diffusely enhancing (50.0 vs. 27.3 %) or diffusely nonenhancing (25.0 vs. 0.0 %), while GBMs were more likely to exhibit focal enhancement (54.6 vs. 10.0 %). Multivariate analysis revealed confirmed histopathology for GBM to significantly affect survival (HR 4.80; 95 % CI 1.86-12.4; p = 0.0012). In conclusion, adult malignant BSGs have an overall poor prognosis, with GBM tumors faring significantly worse than AAs. As AAs and GBMs have differing imaging characteristics, tissue diagnosis may be necessary to accurately determine patient prognosis and identify molecular characteristics which may aid in the treatment of these aggressive tumors.

Utilization of spinal cord stimulation in patients with failed back surgery syndrome.

STUDY DESIGN: Retrospective analysis of a population-based insurance claims data set. OBJECTIVE: To evaluate the use of spinal cord stimulation (SCS) and lumbar reoperation for the treatment of failed back surgery syndrome (FBSS), and examine their associated complications and health care costs. SUMMARY OF BACKGROUND DATA: FBSS is a major source of chronic neuropathic pain and affects up to 40% of patients who undergo lumbosacral spine surgery for back pain. Thus far, few economic analyses have been performed comparing the various treatments for FBSS, with these studies involving small sample sizes. In addition, the nationwide practices in the use of SCS for FBSS are unknown. METHODS: The MarketScan data set was used to analyze patients with FBSS who underwent SCS or spinal reoperation between 2000 and 2009. Propensity score methods were used to match patients who underwent SCS with those who underwent lumbar reoperation to examine health care resource utilization. Postoperative complications were analyzed with multivariate logistic regression. Health care use was analyzed using negative binomial and general linear models. RESULTS: The study cohort included 16,455 patients with FBSS, with 395 undergoing SCS implantation (2.4%). Complication rates at 90 days were significantly lower for SCS than spinal reoperation (P < 0.0001). Also in the matched cohort, hospital stay (P < 0.0001) and associated charges (P = 0.016) were lower for patients with SCS. However outpatient, emergency room, and medication charges were similar between the 2 groups. Overall cost totaling $82,586 at 2 years was slightly higher in the lumbar reoperation group than in the SCS group with total cost of $80,669 (P = 0.88). CONCLUSION: Although previous studies have demonstrated superior efficacy for the treatment of FBSS, SCS remains underused. Despite no significant decreases in overall health care cost with SCS implantation, because it is associated with decreased complications and improved outcomes, this technology warrants closer consideration for the management of chronic pain in patients with FBSS.

Surgery for spinal stenosis: long-term reoperation rates, health care cost, and impact of instrumentation.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To examine the complications, reoperation rates, and resource use after 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 noninstrumented 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 preoperative enrollment. A total of 2385 patients with decompression only and 620 patients with fusion 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 than for those who underwent laminectomy alone, with reoperation rates not differing significantly between these groups. Long-term (≥5 yr) reoperation rates were similar for those undergoing decompression alone versus decompression with fusion (17.3% vs. 16.0%, P = 0.44). Those with instrumented fusions had a slightly higher rate of reoperation than patients with noninstrumented fusions (17.4% vs. 12.2%, P = 0.11) at more than 5 years. The total cost including initial procedure and hospital, outpatient, emergency department, and medication charges at 5 years was similar for those who received decompression alone and fusion. The long-term costs for instrumented and noninstrumented fusions were also similar, totaling $107,056 and $100,471, respectively. CONCLUSION: 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.

Initial experience with extreme angle cervical screw for treatment of trauma and cervical spondylosis.

In this study, we have described our initial experience and surgical technique of extreme angle screw placement in the cervical and upper thoracic spine of a cohort of patients undergoing posterior fusion. This extreme angle screw facilitates rod placement without need for any coronal contouring of the rod or offset connectors despite the varied entry site locations for posterior instrumentation and the different trajectories and pathways of these screws. From ruary 2011 to July 2011, extreme angle screws were placed in twenty consecutive adult patients who underwent posterior cervical, occipital-cervical or cervical-thoracic fusions. The primary diagnosis was cervical spondylotic myelopathy (13), trauma (4), and pseudoarthrosis with stenosis (3). Eight patients had gross instability. A total of 196 screws were placed; half of the cases involved instrumentation at or within the C3-7 segments (10) and the others included constructs extending to occipital bone, C2, T1, or T2 (10). Of all twenty cases, there were no perioperative hardware complications. At long-term follow-up, two patients required reoperation, one for hardware failure and the other for single level symptomatic pseudoarthrosis. We conclude that extreme angle screw use in the posterior cervical spine provides an evolution in posterior instrumentation that maximizes the biomechanical strength of a construct, allows for easy rod placement, and may improve the restoration of sagittal alignment. Overall, extreme angle screws facilitate rod placement even for screws offset from the natural plane of the rod, thereby avoiding the need for coronal contouring or placement of offset connectors.

Spinal cord astrocytomas: a modern 20-year experience at a single institution.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To examine the effect of resection on survival and neurological outcome in a modern cohort of patients with spinal cord astrocytomas and identify prognostic factors for survival. SUMMARY OF BACKGROUND DATA: There are currently no clear treatment guidelines for the management of spinal cord astrocytomas. Additionally there is no conclusive evidence for the surgical resection of these tumors, with some studies even demonstrating worse survival with surgery. However, most studies have examined patients treated prior to the routine use of magnetic resonance imaging and advanced microsurgical techniques. METHODS: We performed a retrospective review of 46 consecutive patients with spinal cord astrocytomas treated at our institution from 1992 to 2012. Univariate and multivariate analyses were used to identify variables associated with survival. RESULTS: The majority of patients (67.4%) underwent surgical resection, with the remaining only receiving biopsy. Of those who underwent resection, only 12.5% of patients underwent gross total resection, all of whom had low-grade astrocytomas. Of all patients, 30.7% worsened compared with their preoperative baseline. The occurrence of worsening increased with high tumor grade (52.9% vs. 27.6%, P = 0.086) and an increased extent of resection (66.7% vs. 18.8%, P = 0.0069). Resection did not provide a survival benefit compared with biopsy alone (P = 0.53). Multivariate analysis revealed high-grade histology (hazard ratio, 11.3; 95% confidence interval, 2.41-53.2; P = 0.0021), tumor dissemination (hazard ratio, 4.24; 95% confidence interval, 1.22-14.8; P = 0.023), and an increasing number of tumor involved levels (hazard ratio, 1.31; 95% confidence interval, 0.99-1.74; P = 0.058) to be associated with worse survival. CONCLUSION: As surgical intervention is associated with a higher rate of neurological complications and lacks a clear benefit, the resection of spinal cord astrocytomas should be reserved for select cases and should be used sparingly.

Radiological evidence of spontaneous spinal arthrodesis in patients with lower lumbar spondylolisthesis.

STUDY DESIGN: Retrospective review of a consecutive series of patients with radiological evidence of spondylolisthesis. OBJECTIVE: To establish the incidence and characteristics of spontaneous spinal arthrodesis in the setting of lower lumbar spondylolisthesis. SUMMARY OF BACKGROUND DATA: Spontaneous spinal arthrodesis of lumbar spondylolisthesis is a finding that is not discussed in the literature outside of isolated case reports. Identifying spontaneous spinal arthrodesis may impact the surgical plan, as patients with existing fusion may not require instrumentation and might require more work to reduce their spondylolisthesis. METHODS: We reviewed a consecutive series of 1490 lumbar spine computed tomography scans from the year 2010 for radiological 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, radiological characteristics including type of spondylolisthesis, and presenting symptomology. Differences between patients in the fused and nonfused cohorts were compared with univariate analysis. RESULTS: A total of 86 separate instances of spondylolisthesis were identified, of which 18 (20.9%) had radiological 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 patients in the fused and nonfused cohorts in terms of average age (fused: 74.3 ± 10.7 yr vs. nonfused: 63.3 ± 18.6 yr, P = 0.019), sex (fused: 88.9% female vs. nonfused: 57.4% female, P = 0.013), and rate of pars defects (fused: 11.1% vs. nonfused: 35.3%, P = 0.047). CONCLUSION: In this study, 20.9% of patients with lumbar spondylolisthesis have radiological signs of spontaneous fusion. Further work is needed to better characterize the natural history and clinical-radiological correlation of spontaneous fusion in spondylolisthesis. LEVEL OF EVIDENCE: 4.