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Robert G. Whitmore, Jill N. Curran, Zarina S. Ali, Praveen V. Mummaneni, Christopher I. Shaffrey, Robert F. Heary, Michael G. Kaiser, Anthony L. Asher, Neil R. Malhotra, Joseph S. Cheng, John Hurlbert, Justin S. Smith, Subu N. Magge, Michael P. Steinmetz, Daniel K. Resnick and Zoher Ghogawala

OBJECT

The authors have established a multicenter registry to assess the efficacy and costs of common lumbar spinal procedures using prospectively collected outcomes. Collection of these data requires an extensive commitment of resources from each site. The aim of this study was to determine whether outcomes data from shorter-interval follow-up could be used to accurately estimate long-term outcome following lumbar discectomy.

METHODS

An observational prospective cohort study was completed at 13 academic and community sites. Patients undergoing single-level lumbar discectomy for treatment of disc herniation were included. SF-36 and Oswestry Disability Index (ODI) data were obtained preoperatively and at 1, 3, 6, and 12 months postoperatively. Quality-adjusted life year (QALY) data were calculated using SF-6D utility scores. Correlations among outcomes at each follow-up time point were tested using the Spearman rank correlation test.

RESULTS

One hundred forty-eight patients were enrolled over 1 year. Their mean age was 46 years (49% female). Eleven patients (7.4%) required a reoperation by 1 year postoperatively. The overall 1-year follow-up rate was 80.4%. Lumbar discectomy was associated with significant improvements in ODI and SF-36 scores (p < 0.0001) and with a gain of 0.246 QALYs over the 1-year study period. The greatest gain occurred between baseline and 3-month follow-up and was significantly greater than improvements obtained between 3 and 6 months or 6 months and 1 year(p < 0.001). Correlations between 3-month, 6-month, and 1-year outcomes were similar, suggesting that 3-month data may be used to accurately estimate 1-year outcomes for patients who do not require a reoperation. Patients who underwent reoperation had worse outcomes scores and nonsignificant correlations at all time points.

CONCLUSIONS

This national spine registry demonstrated successful collection of high-quality outcomes data for spinal procedures in actual practice. Three-month outcome data may be used to accurately estimate outcome at future time points and may lower costs associated with registry data collection. This registry effort provides a practical foundation for the acquisition of outcome data following lumbar discectomy.

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Christopher J. Balamucki, Volker W. Stieber, Thomas L. Ellis, Stephen B. Tatter, Allan F. DeGuzman, Kevin P. McMullen, James Lovato, Edward G. Shaw, Kenneth E. Ekstrand, J. Daniel Bourland, Michael T. Munley, Michael Robbins and Charles Branch

Object

Gamma Knife surgery (GKS) is a treatment option for patients with refractory typical trigeminal neuralgia (TN), TN with atypical features, and atypical types of facial pain. The Gamma Knife’s 201 60Co sources decay with a half-life of 5.26 years. The authors examined whether the decrease in dose rate over 4.6 years between Co source replacements affected the control rates of facial pain in patients undergoing GKS.

Methods

The authors collected complete follow-up data on 239 of 326 GKS procedures performed in patients with facial pain. Patients were classified by their type of pain. The isocenter of a 4-mm collimator helmet was targeted at the proximal trigeminal nerve root, and the dose (80–90 Gy) was prescribed at the 100% isodose line. Patients reported the amount of pain control following radiosurgery by answering a standardized questionnaire.

Eighty percent of patients experienced greater than 50% pain relief, and 56% of patients experienced complete pain relief after GKS. Neither dose rate nor treatment time was significantly associated with either the control rate or degree of pain relief. A significant association between the type of facial pain and the pain control rate after GKS was observed (p < 0.001; Pearson chi-square test).

In their statistical analysis, the authors accounted for changes in prescription dose over time to prevent the dose rate from being a confounding variable. There was no observable effect of the dose rate or of the treatment duration within the typical period to source replacement.

Conclusions

Patients with facial pain appear to receive consistent treatment with GKS at any time during the first half-life of the Co sources.

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Michael A. Garcia, Ann Lazar, Sai Duriseti, David R. Raleigh, Christopher P. Hess, Shannon E. Fogh, Igor J. Barani, Jean L. Nakamura, David A. Larson, Philip Theodosopoulos, Michael McDermott, Penny K. Sneed and Steve Braunstein

OBJECTIVE

High-resolution double-dose gadolinium-enhanced Gamma Knife (GK) radiosurgery-planning MRI (GK MRI) on the day of GK treatment can detect additional brain metastases undiagnosed on the prior diagnostic MRI scan (dMRI), revealing increased intracranial disease burden on the day of radiosurgery, and potentially necessitating a reevaluation of appropriate management. The authors identified factors associated with detecting additional metastases on GK MRI and investigated the relationship between detection of additional metastases and postradiosurgery patient outcomes.

METHODS

The authors identified 326 patients who received GK radiosurgery at their institution from 2010 through 2013 and had a prior dMRI available for comparison of numbers of brain metastases. Factors predictive of additional brain metastases on GK MRI were investigated using logistic regression analysis. Overall survival was estimated by Kaplan-Meier method, and postradiosurgery distant intracranial failure was estimated by cumulative incidence measures. Multivariable Cox proportional hazards model and Fine-Gray regression modeling assessed potential risk factors of overall survival and distant intracranial failure, respectively.

RESULTS

The mean numbers of brain metastases (SD) on dMRI and GK MRI were 3.4 (4.2) and 5.8 (7.7), respectively, and additional brain metastases were found on GK MRI in 48.9% of patients. Frequencies of detecting additional metastases for patients with 1, 2, 3–4, and more than 4 brain metastases on dMRI were 29.5%, 47.9%, 55.9%, and 79.4%, respectively (p < 0.001). An index brain metastasis with a diameter greater than 1 cm on dMRI was inversely associated with detecting additional brain metastases, with an adjusted odds ratio of 0.57 (95% CI 0.4–0.9, p = 0.02). The median time between dMRI and GK MRI was 22 days (range 1–88 days), and time between scans was not associated with detecting additional metastases. Patients with additional brain metastases did not have larger total radiosurgery target volumes, and they rarely had an immediate change in management (abortion of radiosurgery or addition of whole-brain radiation therapy) due to detection of additional metastases. Patients with additional metastases had a higher incidence of distant intracranial failure than those without additional metastases (p = 0.004), with an adjusted subdistribution hazard ratio of 1.4 (95% CI 1.0–2.0, p = 0.04). Significantly worse overall survival was not detected for patients with additional brain metastases on GK MRI (log-rank p = 0.07), with the relative adjusted hazard ratio of 1.07, (95% CI 0.81–1.41, p = 0.65).

CONCLUSIONS

Detecting additional brain metastases on GK MRI is strongly associated with the number of brain metastases on dMRI and inversely associated with the size of the index brain metastasis. The discovery of additional brain metastases at time of GK radiosurgery is very unlikely to lead to aborting radiosurgery but is associated with a higher incidence of distant intracranial failure. However, there is not a significant difference in survival.

▪ CLASSIFICATION OF EVIDENCE Type of question: prognostic; study design: retrospective cohort trial; evidence: Class IV.

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Carolyn J. Sparrey, Jeannie F. Bailey, Michael Safaee, Aaron J. Clark, Virginie Lafage, Frank Schwab, Justin S. Smith and Christopher P. Ames

The goal of this review is to discuss the mechanisms of postural degeneration, particularly the loss of lumbar lordosis commonly observed in the elderly in the context of evolution, mechanical, and biological studies of the human spine and to synthesize recent research findings to clinical management of postural malalignment. Lumbar lordosis is unique to the human spine and is necessary to facilitate our upright posture. However, decreased lumbar lordosis and increased thoracic kyphosis are hallmarks of an aging human spinal column. The unique upright posture and lordotic lumbar curvature of the human spine suggest that an understanding of the evolution of the human spinal column, and the unique anatomical features that support lumbar lordosis may provide insight into spine health and degeneration. Considering evolution of the skeleton in isolation from other scientific studies provides a limited picture for clinicians. The evolution and development of human lumbar lordosis highlight the interdependence of pelvic structure and lumbar lordosis. Studies of fossils of human lineage demonstrate a convergence on the degree of lumbar lordosis and the number of lumbar vertebrae in modern Homo sapiens. Evolution and spine mechanics research show that lumbar lordosis is dictated by pelvic incidence, spinal musculature, vertebral wedging, and disc health. The evolution, mechanics, and biology research all point to the importance of spinal posture and flexibility in supporting optimal health. However, surgical management of postural deformity has focused on restoring posture at the expense of flexibility. It is possible that the need for complex and costly spinal fixation can be eliminated by developing tools for early identification of patients at risk for postural deformities through patient history (genetics, mechanics, and environmental exposure) and tracking postural changes over time.

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Christopher Paul O'Boynick, Mark F. Kurd, Bruce V. Darden II, Alexander R. Vaccaro and Michael G. Fehlings

The understanding of the optimal surgical timing for stabilization in thoracolumbar fractures is severely limited. Thoracolumbar spine fractures can be devastating injuries and are often associated with significant morbidity and mortality. The role of early surgical stabilization (within 48–72 hours of injury) as a vehicle to improve outcomes in these patients has generated significant interest. Goals of early stabilization include improved neurological recovery, faster pulmonary recovery, improved pain control, and decreased health care costs. Opponents cite the potential for increased bleeding, hypotension, and the risk of further cord injury as a few factors that weigh against early stabilization. The concept of spinal cord injury and its relationship to surgical timing remains in question. However, when neurological outcomes are eliminated from the equation, certain measures have shown positive influences from prompt surgical fixation.

Early fixation of thoracolumbar spine fractures can significantly decrease the duration of hospital stay and the number of days in the intensive care unit. Additionally, prompt stabilization can reduce rates of pulmonary complications. This includes decreased rates of pneumonia and fewer days on ventilator support. Cost analysis revealed as much as $80,000 in savings per patient with early stabilization. All of these benefits come without an increase in morbidity or evidence of increased mortality. In addition, there is no evidence that early stabilization has any ill effect on the injured or uninjured spinal cord. Based on the existing data, early fixation of thoracolumbar fractures has been linked with positive outcomes without clear evidence of negative impacts on the patient's neurological status, associated morbidities, or mortality. These procedures can be viewed as “damage control” and may consist of simple posterior instrumentation or open reductions with internal fixation as indicated. Based on the current literature it is advisable to proceed with early surgical stabilization of thoracolumbar fractures in a well-resuscitated patient, unless extenuating medical conditions would prevent it.

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Brian Y. Hwang, Samuel S. Bruce, Geoffrey Appelboom, Matthew A. Piazza, Amanda M. Carpenter, Paul R. Gigante, Christopher P. Kellner, Andrew F. Ducruet, Michael A. Kellner, Rajeev Deb-Sen, Kerry A. Vaughan, Philip M. Meyers and E. Sander Connolly Jr.

Object

Intraventricular hemorrhage (IVH) associated with intracerebral hemorrhage (ICH) is an independent predictor of poor outcome. Clinical methods for evaluating IVH, however, are not well established. This study sought to determine the best IVH grading scale by evaluating the predictive accuracies of IVH, Graeb, and LeRoux scores in an independent cohort of ICH patients with IVH. Subacute IVH dynamics as well as the impact of external ventricular drain (EVD) placement on IVH and outcome were also investigated.

Methods

A consecutive cohort of 142 primary ICH patients with IVH was admitted to Columbia University Medical Center between February 2009 and February 2011. Baseline demographics, clinical presentation, and hospital course were prospectively recorded. Admission CT scans performed within 24 hours of onset were reviewed for ICH location, hematoma volume, and presence of IVH. Intraventricular hemorrhage was categorized according to IVH, Graeb, and LeRoux scores. For each patient, the last scan performed within 6 days of ictus was similarly evaluated. Outcomes at discharge were assessed using the modified Rankin Scale (mRS). Receiver operating characteristic analysis was used to determine the predictive accuracies of the grading scales for poor outcome (mRS score ≥ 3).

Results

Seventy-three primary ICH patients (51%) had IVH. Median admission IVH, Graeb, and LeRoux scores were 13, 6, and 8, respectively. Median IVH, Graeb and LeRoux scores decreased to 9 (p = 0.005), 4 (p = 0.002), and 4 (p = 0.003), respectively, within 6 days of ictus. Poor outcome was noted in 55 patients (75%). Areas under the receiver operating characteristic curve were similar among the IVH, Graeb, and LeRoux scores (0.745, 0.743, and 0.744, respectively) and within 6 days postictus (0.765, 0.722, 0.723, respectively). Moreover, the IVH, Graeb, and LeRoux scores had similar maximum Youden Indices both at admission (0.515 vs 0.477 vs 0.440, respectively) and within 6 days postictus (0.515 vs 0.339 vs 0.365, respectively). Patients who received EVDs had higher mean IVH volumes (23 ± 26 ml vs 9 ± 11 ml, p = 0.003) and increased incidence of Glasgow Coma Scale scores < 8 (67% vs 38%, p = 0.015) and hydrocephalus (82% vs 50%, p = 0.004) at admission but had similar outcome as those who did not receive an EVD.

Conclusions

The IVH, Graeb, and LeRoux scores predict outcome well with similarly good accuracy in ICH patients with IVH when assessed at admission and within 6 days after hemorrhage. Therefore, any of one of the scores would be equally useful for assessing IVH severity and risk-stratifying ICH patients with regard to outcome. These results suggest that EVD placement may be beneficial for patients with severe IVH, who have particularly poor prognosis at admission, but a randomized clinical trial is needed to conclusively demonstrate its therapeutic value.

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Zeev Feldman, Malcolm J. Kanter, Claudia S. Robertson, Charles F. Contant, Christopher Hayes, Michael A. Sheinberg, Cynthia A. Villareal, Raj K. Narayan and Robert G. Grossman

✓ The traditional practice of elevating the head in order to lower intracranial pressure (ICP) in head-injured patients has been challenged in recent years. Some investigators argue that patients with intracranial hypertension should be placed in a horizontal position, the rationale being that this will increase the cerebral perfusion pressure (CPP) and thereby improve cerebral blood flow (CBF). However, ICP is generally significantly higher when the patient is in the horizontal position. This study was undertaken to clarify the issue of optimal head position in the care of head-injured patients. The effect of 0° and 30° head elevation on ICP, CPP, CBF, mean carotid pressure, and other cerebral and systemic physiological parameters was studied in 22 head-injured patients. The mean carotid pressure was significantly lower when the patient's head was elevated at 30° than at 0° (84.3 ± 14.5 mm Hg vs. 89.5 ± 14.6 mm Hg), as was the mean ICP (14.1 ± 6.7 mm Hg vs. 19.7 ± 8.3 mm Hg). There was no statistically significant change in CPP, CBF, cerebral metabolic rate of oxygen, arteriovenous difference of lactate, or cerebrovascular resistance associated with the change in head position. The data indicate that head elevation to 30° significantly reduced ICP in the majority of the 22 patients without reducing CPP or CBF.

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Eric S. Sussman, Christopher P. Kellner, Michael M. McDowell, Samuel S. Bruce, Simon G. Heuts, Zong Zhuang, Rachel A. Bruce, Jan Claassen and E. Sander Connolly Jr.

Intracerebral hemorrhage (ICH) is the most deadly and least treatable subtype of stroke, and at the present time there are no evidence-based therapeutic interventions for patients with this disease. Secondary injury mechanisms are known to cause substantial rates of morbidity and mortality following ICH, and the inflammatory cascade is a major contributor to this post-ICH secondary injury. The alpha-7 nicotinic acetylcholine receptor (α7-nAChR) agonists have a well-established antiinflammatory effect and have been shown to attenuate perihematomal edema volume and to improve functional outcome in experimental ICH. The authors evaluate the current evidence for the use of an α7-nAChR agonist as a novel therapeutic agent in patients with ICH.

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Eric S. Sussman, Christopher P. Kellner, Joanna L. Mergeche, Samuel S. Bruce, Michael M. McDowell, Eric J. Heyer and E. Sander Connolly

Object

Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD.

Methods

Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA.

Results

Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43–64.92, p = 0.02).

Conclusions

The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 (http://www.clinicaltrials.gov).