243 research outputs found
Cervical spine surgery for tandem spinal stenosis: The impact on low back pain
Objective
Tandem spinal stenosis (TSS) can present similarly to cervical myelopathy, but often has a worse prognosis. Few studies have investigated outcomes and compared treatment approaches for patients with TSS. We sought to determine the impact of cervical spine surgery on cervical and lumbar spine symptoms in patients with symptomatic tandem spinal stenosis.
Patients Methods
84 patients with TSS were identified over 5 years. 48 underwent cervical spine surgery alone, 20 underwent both cervical and lumbar spine surgery, and 16 received conservative treatment alone (conservative cohort). Quality of life (QOL) measures included the Visual Analogue Scale (VAS) for arm, neck, and back pain, and EuroQOL-5 Dimensions (EQ-5D). QOL data were acquired at baseline (pre-operative) and 1 year postoperatively via an institutional prospectively collected database.
Results
Both surgical cohorts showed significant (p < 0.01) pre- to postoperative improvement for VAS neck and arm scores at 1-year post-op and significantly (p < 0.01) greater improvements than the conservative cohort. In addition, the cohort undergoing cervical spine surgery alone experienced significant improvement in the EQ-5D score whereas those undergoing both cervical and lumbar spine surgery did not.
Conclusions
Cervical spine surgery with or without follow-up lumbar spine surgery significantly improves neck pain in patients with TSS. In contrast, cervical spine surgery in these patients does not improve lumbar symptoms. Lumbar surgery also did not improve low back pain or quality of life. Future prospective studies are necessary to examine the impact of lumbar decompression alone on cervical spine symptoms in patients with TSS
Preliminary Results of Relationship between Preoperative Walking Ability and Magnetic Resonance Imaging Morphology in Patients with Lumbar Canal Stenosis: Comparison between Trefoil and Triangle Types of Spinal Stenosis
Study DesignCross-sectional.PurposeTo examine the relationship between magnetic resonance imaging (MRI) morphology stenosis grades and preoperative walking ability in patients with lumbar canal stenosis (LCS).Overview of LiteratureNo previous study has analyzed the correlation between MRI morphology stenosis grades and walking ability in patients with LCS.MethodsThis prospective study included 98 consecutive patients with LCS who were candidates for surgery. Using features identified in T2-weighted axial magnetic, stenosis type was determined at the maximal stenosis level, and only trefoil and triangle stenosis grade types were considered because of sufficient sample size. Intraobserver and interobserver reliability were assessed by calculating weighted kappa coefficients. Symptom severity was evaluated via the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). Walking ability was assessed using the Self-Paced Walking Test (SPWT) and JOABPEQ subscales. Demographic characteristics, SPWT scores, and JOABPEQ scores were compared between patients with trefoil and triangle stenosis types.ResultsThe mean patient age was 58.1 (standard deviation, 8.4) years. The kappa values of the MRI morphology stenosis grade types showed a perfect agreement between the stenosis grade types. The trefoil group (n=53) and triangle group (n=45) showed similar preoperative JOABPEQ subscale scores (e.g., low back pain, lumbar function, and mental health) and were not significantly different in age, BMI, duration of symptoms, or lumbar stenosis levels (all p>0.05); however, trefoil stenosis grade type was associated with a decreased walking ability according to the SPWT and JOABPEQ subscale scores.ConclusionsThese findings suggest preoperative walking ability is more profoundly affected in patients with trefoil type stenosis than in those with triangle type stenosis
Notes on Lithology, Mineralogy, and Production for Lunar Simulants
The creation of lunar simulants requires a very broad range of specialized knowledge and information. This document covers several topic areas relevant to lithology, mineralogy, and processing of feedstock materials that are necessary components of the NASA lunar simulant effort. The naming schemes used for both terrestrial and lunar igneous rocks are discussed. The conflict between the International Union of Geological Sciences standard and lunar geology is noted. The rock types known as impactites are introduced. The discussion of lithology is followed by a brief synopsis of pyroxene, plagioclase, and olivine, which are the major mineral constituents of the lunar crust. The remainder of the text addresses processing of materials, particularly the need for separation of feedstock minerals. To illustrate this need, the text includes descriptions of two norite feedstocks for lunar simulants: the Stillwater Complex in Montana, United States, and the Bushveld Complex in South Africa. Magnetic mineral separations, completed by Hazen Research, Inc. and Eriez Manufacturing Co. for the simulant task, are discussed
Explicit Lie-Poisson integration and the Euler equations
We give a wide class of Lie-Poisson systems for which explicit, Lie-Poisson
integrators, preserving all Casimirs, can be constructed. The integrators are
extremely simple. Examples are the rigid body, a moment truncation, and a new,
fast algorithm for the sine-bracket truncation of the 2D Euler equations.Comment: 7 pages, compile with AMSTEX; 2 figures available from autho
Superior Segment Facet Joint Violation During Instrumented Lumbar Fusion is Associated With Higher Reoperation Rates and Diminished Improvement in Quality of Life
Study Design: A retrospective cohort study at a single tertiary care center.
Objective: To determine the impact of superior segment facet joint violation (FJV) during lumbar fusion on reoperation rates and quality of life (QOL).
Summary of Background Data: Although lumbar fusion is an efficacious and durable treatment for numerous spinal pathologies, adjacent segment degeneration remains a serious complication. FJV has been suggested to alter load-bearing capability and potentially contribute to adjacent segment degeneration.
Materials and Methods: Patients who underwent instrumented lumbar fusion surgery between 2009 and 2013 with postoperative computed tomography imaging were included. Patients were placed in the FJV group if either of the superior segment facet joints were compromised by the pedicle screw or rod. Patients with preserved facet joints were placed in the control group. Demographic, perioperative, QOL, and reoperation data were collected. QOL scores including the Pain Disability Questionnaire, Patient Health Questionnaire-9, and EuroQOL 5 Dimensions (EQ-5D) were acquired.
Results: Of 240 patients included, 112 patients were found to have FJV and the remaining 128 patients were placed in the control group. One year following lumbar fusion, QOL outcomes and reoperation rates were similar between the FJV and control groups. At 2-year follow-up, patients in the FJV group were less likely to make a significant improvement in EQ-5D (P=0.041). Also, the reoperation rate in the FJV group was significantly higher than in the control group at 2 years (15.2% vs. 6.3%, respectively; P=0.024) and 3 years (19.6% vs. 9.4%, P=0.023). Multivariable logistic regression showed FJV to be an independent predictor of both (1) failing to make a significant improvement in EQ-5D (P=0.046) and (2) undergoing reoperation at both 2 and 3 years postoperatively (P=0.024 and 0.020, respectively).
Conclusions: FJV was independently associated with a higher reoperation rate and diminished improvement in QOL
d-Amino acid oxidase and serine racemase in human brain: normal distribution and altered expression in schizophrenia
The N-methyl-d-aspartate receptor co-agonist d-serine is synthesized by serine racemase and degraded by d-amino acid oxidase. Both d-serine and its metabolizing enzymes are implicated in N-methyl-d-aspartate receptor hypofunction thought to occur in schizophrenia. We studied d-amino acid oxidase and serine racemase immunohistochemically in several brain regions and compared their immunoreactivity and their mRNA levels in the cerebellum and dorsolateral prefrontal cortex in schizophrenia. d-Amino acid oxidase immunoreactivity was abundant in glia, especially Bergmann glia, of the cerebellum, whereas in prefrontal cortex, hippocampus and substantia nigra, it was predominantly neuronal. Serine racemase was principally glial in all regions examined and demonstrated prominent white matter staining. In schizophrenia, d-amino acid oxidase mRNA was increased in the cerebellum, and as a trend for protein. Serine racemase was increased in schizophrenia in the dorsolateral prefrontal cortex but not in cerebellum, while serine racemase mRNA was unchanged in both regions. Administration of haloperidol to rats did not significantly affect serine racemase or d-amino acid oxidase levels. These findings establish the major cell types wherein serine racemase and d-amino acid oxidase are expressed in human brain and provide some support for aberrant d-serine metabolism in schizophrenia. However, they raise further questions as to the roles of d-amino acid oxidase and serine racemase in both physiological and pathophysiological processes in the brain
Sustaining the National Spinal Cord Injury Registry of Iran (NSCIR-IR) in a Regional Center: Challenges and Solutions
Background: The National Traumatic Spinal Cord Injury Registry in Iran (NSCIR-IR), was implemented initially in three hospitals as a pilot phase from 11 Oct 2015 to 19 Jun 2016 and has been active in eight centers from 19 Jun 2016. Poursina Hospital, a trauma care referral center in Rasht, Guilan Province of Iran is one of the registry sites, and has been involved in registering eligible patients since 1 Jan 2016. This study aimed to identify the challenges and solutions for sustaining the NSCIR-IR in a regional center.
Methods: This was a mixed-methods study. For the quantitative analysis, a retrospective observational design was used to measure case capture or case identification rate, mapping cases in the registry against those eligible for registry inclusion amongst the register of hospital admissions. For the qualitative component, data was collected using focus group discussions and semi-structured interviews, followed by thematic analysis.
Results: From 19 Jun 2016 to 24 Jan 2018, the proportion of case capture (case identification rate) was 17%. The median time between case identification and data entry to the system was 30.5 d (range: 2 to 193 d). Thematic analysis identified a lack of trained human resources as the most important cause of low case identification rate and delay in data completion.
Conclusion: Recruitment and education to increase trained human resources are needed to improve case capture, the timeliness of data input and registry sustainability in a regional participating site
Lumbar Spinal Canal Stenosis Classification Criteria: A New Tool
Study DesignCase-control study.PurposeTo design a new tool for classifying lumbar spinal canal stenosis (CLSCS).Overview of LiteratureGrading of patients with lumbar spinal canal stenosis (LSCS) is controversial.MethodsThe Oswestry disability index (ODI) and the neurogenic claudication outcome score (NCOS) were recorded. Four parameters, which indicate the severity of LSCS disease, including Hufschmidt-grade, grading of magnetic resonance imaging, self-paced walking test, and stenosis ratio (SR) were employed. For the SR, quartile analysis was applied for classifying LSCS and the Hufschmidt-grade was modified into a 4-grade score. An initial score was assigned to each metric based on the severity of LSCS. Using the inverse-variance weighting method, the relative weights of these domains and their categories were determined. The score for all of the cases was obtained based on their weight by summing up the points of the four variables. Quartile analysis was used and a CLSCS score was proposed. Finally, intra- and interobserver reliability, and validity were assessed.ResultsA total of 357 patients were studied. The final CLSCS score for each case ranged from 4 to 16.5. Based on the quartile analysis, using the new criteria set, the CLSCS score was divided into four categories: CLSCS<7 (grade 0); 7≤CLSCS<10 (grade 1); 10≤CLSCS<13 (grade 2); and 13≤CLSCS≤16.5 (grade 3). The kappa values of for the CLSCS score indicated a perfect agreement. The CLSCS was correlated with the ODI and NCOS. All patients with grade 3 CLSCS were observed in the surgical group.ConclusionsThe CLSCS score can be helpful for classifying LSCS patients and in the decision-making process
Variability in Surgical Treatment of Spondylolisthesis Among Spine Surgeons
Background
There are a multitude of treatments for low-grade lumbar spondylolisthesis. There are no clear guidelines for the optimal approach.
Objective
To identify the surgical treatment patterns for spondylolisthesis among United States spine surgeons.
Methods
445 spine surgeons in the United States completed a survey of clinical/radiographic case scenarios on patients with lumbar spondylolisthesis with neurogenic claudication with (S+BP) or without (S−BP) associated mechanical back pain. Treatment options included decompression, laminectomy with posterolateral fusion, posterior lumbar interbody fusion, or none of the above. The primary outcome measure was the probability of 2 randomly chosen surgeons disagreeing on the treatment method.
Results
There was 64% disagreement (36% agreement) among surgeons for treatment of spondylolisthesis with mechanical back pain (S+BP) and 71% disagreement (29% agreement) for spondylolisthesis without mechanical back pain (S−BP). For S+BP, disagreement was 52% for those practicing 5 to 10 years versus 70% among those practicing more than 20 years. Orthopedic surgeons had greater disagreement than did neurosurgeons (76% vs. 56%) for S+BP. Greater clinical equipoise was seen for S−BP than for S+BP regardless of surgeon characteristics. For spondylolisthesis without mechanical back pain, neurosurgeons were significantly more likely to select decompression-only than were orthopedic surgeons, who more commonly selected fusion.
Conclusions
Clinical equipoise exists for the treatment of spondylolisthesis. Differences are greater when the patient presents without associated back pain. Surgeon case volume, practice duration, and specialty training influence operative decisions for a given pathologic condition. Recognizing this practice variation will hopefully lead to better evidence and practice guidelines for the optimal and most cost-effective treatment paradigms
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