Characterization of Brain Dysfunction Induced by Bacterial Lipopeptides That Alter Neuronal Activity and Network in Rodent Brains.

The immunopathological states of the brain induced by bacterial lipoproteins have been well characterized by using biochemical and histological assays. However, these studies have limitations in determining functional states of damaged brains involving aberrant synaptic activity and network, which makes it difficult to diagnose brain disorders during bacterial infection. To address this, we investigated the effect of Pam3CSK4 (PAM), a synthetic bacterial lipopeptide, on synaptic dysfunction of female mice brains and cultured neurons in parallel. Our functional brain imaging using PET with [18F]fluorodeoxyglucose and [18F] flumazenil revealed that the brain dysfunction induced by PAM is closely aligned to disruption of neurotransmitter-related neuronal activity and functional correlation in the region of the limbic system rather than to decrease of metabolic activity of neurons in the injection area. This finding was verified by in vivo tissue experiments that analyzed synaptic and dendritic alterations in the regions where PET imaging showed abnormal neuronal activity and network. Recording of synaptic activity also revealed that PAM reorganized synaptic distribution and decreased synaptic plasticity in hippocampus. Further study using in vitro neuron cultures demonstrated that PAM decreased the number of presynapses and the frequency of miniature EPSCs, which suggests PAM disrupts neuronal function by damaging presynapses exclusively. We also showed that PAM caused aggregation of synapses around dendrites, which may have caused no significant change in expression level of synaptic proteins, whereas synaptic number and function were impaired by PAM. Our findings could provide a useful guide for diagnosis and treatment of brain disorders specific to bacterial infection.SIGNIFICANCE STATEMENT It is challenging to diagnose brain disorders caused by bacterial infection because neural damage induced by bacterial products involves nonspecific neurological symptoms, which is rarely detected by laboratory tests with low spatiotemporal resolution. To better understand brain pathology, it is essential to detect functional abnormalities of brain over time. To this end, we investigated characteristic patterns of altered neuronal integrity and functional correlation between various regions in mice brains injected with bacterial lipopeptides using PET with a goal to apply new findings to diagnosis of brain disorder specific to bacterial infection. In addition, we analyzed altered synaptic density and function using both in vivo and in vitro experimental models to understand how bacterial lipopeptides impair brain function and network.

Posterior open reduction and internal fixation of C1 fractures: the C-clamp technique.

BACKGROUND: The treatment of isolated atlas (C1) fractures is still controversial. The surgical management usually involves an arthrodesis of the atlanto-axial (C1-C2) joint with or without occipital fixation. We reviewed the senior author's series of posterior only open reduction and internal fixation (ORIF) of isolated C1 fractures. METHODS: Retrospective analysis of consecutive patients with isolated C1 fractures, treated in one institution by posterior only ORIF between 2005 and 2017. All fractures of C1 with concomitant C2 or occipital condyle fractures were excluded. The C1 arch was reduced with C1 lateral mass screws, connected with a transverse rod in a C-clamp fashion. We analyzed neck pain on the visual analog scale (VAS) and imaging signs of instability on follow-up. RESULTS: We identified eight patients, six males, and two females with a mean age of 37.9 years (range 20-71 years). All were neurologically intact before surgery, none had a documented transverse ligament disruption, and the mean gap between the fractured pieces was 5.3 mm. Five patients were treated < 72 h of injury, two patients had failed halo vest for 8-10 weeks, and one patient was operated after 6 months because of painful pseudarthrosis despite wearing a hard collar. One patient developed a transient neurological deficit due to vertebral artery dissection that had resolved completely at time of follow-up. The mean follow-up after surgery was 12.6 months (range 1-49 months) and mean preoperative neck pain (VAS 5.1) was significantly decreased (VAS 0.8; p < 0.001). On follow-up radiological evaluation, no instability was noted in any patient. CONCLUSIONS: Posterior ORIF of C1 fractures may be an option for patients who fail or do not wish to pursue conservative management. The particular advantage of this technique over C1-C2 arthrodesis is the preserved range of rotational motion. Mono-axial screws seem to provide better reduction capacity.

Sacral Peak Pressure in Healthy Volunteers and Patients With Spinal Cord Injury: With and Without Liquid-Based Pad.

BACKGROUND: The prevalence of sacral pressure ulcers in patients with spinal cord injuries is high. The sacral area is vulnerable to compressive pressure because of immobility and because the sacrum and posterior superior iliac prominence lie closely under the skin with no muscle layer in between. OBJECTIVE: The aim of this study was to assess peak sacral pressure before and after use of PURAP, a liquid-based pad that covers only the sacral area and can be applied on any bed surface. METHODS: Healthy volunteers (n = 12) and patients with spinal cord injuries (n = 10) took part; the patients had undergone spine surgery within 7 days before data collection. Participants were in bed, pretest pressure maps were generated, PURAP was placed for 15 minutes, and then posttest pressure maps were generated. Peak pressure was obtained every second and averaged over the entire period. Patients rated whether their comfort had improved when PURAP was in use. RESULTS: For healthy volunteers, mean pretest peak sacral pressure was 74.7 (SD = 16.2) mmHg; the posttest mean was 49.1 (SD = 7.5) mmHg (p < .001, Wilcoxon signed-rank test). For patients with spinal cord injuries, mean pretest peak sacral pressure was 105.7 (SD = 22.4) mmHg; the posttest mean was 81.4 (SD = 18.3) mmHg (p < .001, Wilcoxon signed-rank test). The pad reduced the peak sacral pressure in the patient group by 23% (range = 11%-42%) and in the volunteers by 32% (range = 19%-46%). Overall, 70% of the patients reported increased comfort with PURAP. DISCUSSION: Peak sacral pressure was reduced when PURAP was used. It covers only the sacral area but could help many patients with spinal cord injury because the prevalence of sacral pressure ulcers is high in this group. PURAP may be economically advantageous in countries and hospitals with limited financial resources needed for more expensive mattresses and cushions.

Treatment Concept and Technical Considerations of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis.

Decompression is a major component of surgical procedures for degenerative lumbar spinal stenosis (LSS). In addition to sufficient decompression to guarantee the relief of neurological pain, compensating surgical instability after wider laminectomy and foraminotomy and instrumentation with caging and fusion with grafting are performed to secure or restore the foraminal dimension and correct coronal/sagittal imbalance for longer survival of the adjacent segment. Endoscopic spinal surgery (ESS) has been developed under the flag of successful decompression while preserving structural integrity as much as possible with the help of magnification and illumination. ESS provides a technical possibility and feasibility for solving LSS by decompression alone. Recently, many endoscopic trials have been conducted to overcome conventional surgical treatment that requires wider dissection, escape inevitable complications from surgical damage, and compensate for the fusion technique. However, biportal ESS has some technical limitations, including clinical difficulties in accessibility for more moderate to severe stenosis and challenges for complicated conditions with segmental ventral slip, isthmic defect, stenosis combined with foraminal stenosis or foraminal disk rupture, or degenerative segmental scoliosis with disk height collapsing and endplate fatigue fracture. Because decompression alone is a skill for eliminating pathologies, there is no function of preserving degenerative structure or stopping the recurrence of disk degeneration or subsidence. This review of clinical reports investigated the possibility of biportal ESS for treating degenerative lumbar disorders by sufficient decompression and adequate elimination of various pathologies and decreasing technical complications. The results of this study may help develop better innovative spinal surgical techniques in the near future.

External validation of a predictive model of adverse events following spine surgery.

BACKGROUND CONTEXT: We lack models that reliably predict 30-day postoperative adverse events (AEs) following spine surgery. PURPOSE: We externally validated a previously developed predictive model for common 30-day adverse events (AEs) after spine surgery. STUDY DESIGN/SETTING: This prospective cohort study utilizes inpatient and outpatient data from a tertiary academic medical center. PATIENT SAMPLE: We assessed a prospective cohort of all 276 adult patients undergoing spine surgery in the Department of Neurosurgery at a tertiary academic institution between April 1, 2018 and October 31, 2018. No exclusion criteria were applied. OUTCOME MEASURES: Incidence of observed AEs was compared with predicted incidence of AEs. Fifteen assessed AEs included: pulmonary complications, congestive heart failure, neurological complications, pneumonia, cardiac dysrhythmia, renal failure, myocardial infarction, wound infection, pulmonary embolus, deep venous thrombosis, wound hematoma, other wound complication, urinary tract infection, delirium, and other infection. METHODS: Our group previously developed the Risk Assessment Tool for Adverse Events after Spine Surgery (RAT-Spine), a predictive model of AEs within 30 days following spine surgery using a cohort of approximately one million patients from combined Medicare and MarketScan databases. We applied RAT-Spine to the single academic institution prospective cohort by entering each patient's preoperative medical and demographic characteristics and surgical type. The model generated a patient-specific overall risk score ranging from 0 to 1 representing the probability of occurrence of any AE. The predicted risks are presented as absolute percent risk and divided into low (<17%), medium (17%-28%), and high (>28%). RESULTS: Among the 276 patients followed prospectively, 76 experienced at least one 30-day postoperative AE. Slightly more than half of the cohort were women (53.3%). The median age was slightly lower in the non-AE cohort (63 vs. 66.5 years old). Patients with Medicaid comprised 2.5% of the non-AE cohort and 6.6% of the AE cohort. Spinal fusion was performed in 59.1% of cases, which was comparable across cohorts. There was good agreement between the predicted AE and observed AE rates, Area Under the Curve (AUC) 0.64 (95% CI 0.56-0.710). The incidence of observed AEs in the prospective cohort was 17.8% among the low-risk group, 23.0% in the medium-risk group, and 38.4% in the high risk group (p =.003). CONCLUSIONS: We externally validated a model for postoperative AEs following spine surgery (RAT-Spine). The results are presented as low-, moderate-, and high-risk designations.

A neurovascular-unit-on-a-chip for the evaluation of the restorative potential of stem cell therapies for ischaemic stroke.

The therapeutic efficacy of stem cells transplanted into an ischaemic brain depends primarily on the responses of the neurovascular unit. Here, we report the development and applicability of a functional neurovascular unit on a microfluidic chip as a microphysiological model of ischaemic stroke that recapitulates the function of the blood-brain barrier as well as interactions between therapeutic stem cells and host cells (human brain microvascular endothelial cells, pericytes, astrocytes, microglia and neurons). We used the model to track the infiltration of a number of candidate stem cells and to characterize the expression levels of genes associated with post-stroke pathologies. We observed that each type of stem cell showed unique neurorestorative effects, primarily by supporting endogenous recovery rather than through direct cell replacement, and that the recovery of synaptic activities is correlated with the recovery of the structural and functional integrity of the neurovascular unit rather than with the regeneration of neurons.

Acute care surgery performed by sleep deprived residents: are outcomes affected?

BACKGROUND: The Institute of Medicine recently recommended further reductions in resident duty hours, including a 5-h rest time for on-call residents after 16 h of work. This recommendation was purportedly intended to better protect patients against fatigue-related errors made by physician trainees. Yet no data are available regarding outcomes of operations performed by surgical trainees working without rest beyond 16 h in the current 80-h workweek era. METHODS: A retrospective review of all laparoscopic cholecystectomies (LC) and appendectomies performed by surgery residents at a public teaching hospital from July 2003 through March 2009. Operations after 10 PM were performed by residents who began their shift at 6 AM and had thus been working 16 or more hours. An outcomes comparison between time periods was conducted for operations performed between 6 AM and 10 PM (daytime) and 10 PM and 6 AM (nighttime). Outcome measures were rates of total complications, bile duct injury, conversion to open operation, length of surgery, and mortality. RESULTS: Over the 7-y study period, 2908 LC and 1726 appendectomies were performed. Appendectomies were performed laparoscopically in 73% of cases in patients for both time periods. There were no differences in rates of overall morbidity and mortality for operations when performed in nighttime compared with daytime. On multivariable analysis, there were no differences in outcomes between the two groups. CONCLUSION: The two most commonly performed general surgical operations performed at night by unrested residents have favorable outcomes similar to those performed during the day. Instituting a 5-h rest period at night is unlikely to improve the outcomes for these commonly performed operations.

Surgical strategies for managing foraminal nerve sheath tumors: the emerging role of CyberKnife ablation.

Sixteen Stanford University Medical Center (SUMC) patients with foraminal nerve sheath tumors had charts reviewed. CyberKnife radiosurgery was innovative in management. Parameters were evaluated for 16 foraminal nerve sheath tumors undergoing surgery, some with CyberKnife. Three neurofibromas had associated neurofibromatosis type 1 (NF1). Eleven patients had one resection; others had CyberKnife after one (two) and two (three) operations. The malignant peripheral nerve sheath tumor (MPNST) had prior field-radiation and adds another case. Approaches included laminotomy and laminectomies with partial (three) or total (two) facetectomies/fusions. Two cases each had supraclavicular, lateral extracavitary, retroperitoneal and Wiltze and costotransversectomy/thoracotomy procedures. Two underwent a laminectomy/partial facetectomy, then CyberKnife. Pre-CyberKnife, one of two others had a laminectomy/partial facetectomy, then total facetectomy/fusion and the other, two supraclavicular approaches. The MPNST had a hemi-laminotomy then laminectomy/total facetectomy/fusion, followed by CyberKnife. Roots were preserved, except in two. Of 11 single-operation-peripheral nerve sheath tumors, the asymptomatic case remained stable, nine (92%) improved and one (9%) worsened. Examinations remained intact in three (27%) and improved in seven (64%). Two having a single operation then CyberKnife had improvement after both. Of two undergoing two operations, one had symptom resolution post-operatively, worsened 4 years post-CyberKnife then has remained unchanged after re-operation. The other such patient improved post-operatively, had no change after re-operation and improved post-CyberKnife. The MPNST had presentation improvement after the first operation, worsened and after the second surgery \and CyberKnife, the patient expired from tumor spread. In conclusion, surgery is beneficial for pain relief and function preservation in foraminal nerve sheath tumors. Open surgery with CyberKnife is an innovation in these tumors' management.

Association Between Physician Industry Payments and Cost of Anterior Cervical Discectomy and Fusion in Medicare Beneficiaries.

BACKGROUND: Neurosurgical spine specialists receive considerable amounts of industry support that may impact the cost of care. The aim of this study was to evaluate the association between industry payments received by spine surgeons and the total hospital and operating room (OR) costs of an anterior cervical discectomy and fusion (ACDF) procedure among Medicare beneficiaries. METHODS: All ACDF cases were identified among the Medicare carrier files from January 1, 2013, to December 31, 2014, and matched to the Medicare inpatient baseline file. The total hospital and OR charges were obtained for these cases. Charges were converted to cost using year-specific cost-to-charge ratios. Surgeons were identified among the Open Payments database, which is used to quantify industry support. Analyses were performed to examine the association between industry payments received and ACDF costs. RESULTS: Matching resulting in the inclusion of 2209 ACDF claims from 2013-2014. In 2013 and 2014, the mean total cost for an ACDF was $21,798 and $21,008, respectively; mean OR cost was $5878 and $6064, respectively. Mann-Whitney U test demonstrated no significant differences in the mean total or OR cost for an ACDF based on quartile of general industry payment received (P = 0.21 and P = 0.54), and linear regression found no association between industry general payments, research support, or investments on the total hospital cost (P = 0.41, P = 0.13, and P = 0.25, respectively), or OR cost for an ACDF (P = 0.35, P = 0.24, and P = 0.40, respectively). CONCLUSIONS: This study suggests that spine surgeons performing ACDF surgeries may receive industry support without impacting the cost of care.

Objective activity tracking in spine surgery: a prospective feasibility study with a low-cost consumer grade wearable accelerometer.

Patient-reported outcome measures (PROMs) are commonly used to estimate disability of patients with spinal degenerative disease. Emerging technological advances present an opportunity to provide objective measurements of activity. In a prospective, observational study we utilized a low-cost consumer grade wearable accelerometer (LCA) to determine patient activity (steps per day) preoperatively (baseline) and up to one year (Y1) after cervical and lumbar spine surgery. We studied 30 patients (46.7% male; mean age 57 years; 70% Caucasian) with a baseline activity level of 5624 steps per day. The activity level decreased by 71% in the 1st postoperative week (p < 0.001) and remained 37% lower in the 2nd (p < 0.001) and 23% lower in the 4th week (p = 0.015). At no time point until Y1 did patients increase their activity level, compared to baseline. Activity was greater in patients with cervical, as compared to patients with lumbar spine disease. Age, sex, ethnic group, anesthesia risk score and fusion were variables associated with activity. There was no correlation between activity and PROMs, but a strong correlation with depression. Determining activity using LCAs provides real-time and longitudinal information about patient mobility and return of function. Recovery took place over the first eight postoperative weeks, with subtle improvement afterwards.

Fracture-related thoracic kyphotic deformity correction by single-stage posterolateral vertebrectomy with circumferential reconstruction and stabilization: Outcomes in 30 cases.

STUDY DESIGN: This paper is a retrospective chart review. OBJECTIVE: This study assesses single-stage thoracic vertebrectomy with circumferential reconstruction and stabilization. Preoperative and postoperative thoracic kyphotic angles and other outcomes are analyzed. SUMMARY OF BACKGROUND DATA: Pathologic and traumatic thoracic vertebral body fracture deformity can be corrected by an anterior vertebral body corpectomy and reconstruction. If the pathology is primarily posterior, then laminectomy and posterolateral instrumentation may be preferred. In some patients, simultaneous anterior and posterior correction of instability and fracture is necessary and is now possible with a single-stage Stanford University Medical Center (SUMC) technique with similar results to the traditional 2-stage approach. METHODS: Thirty patients who underwent 31 single-stage thoracic vertebrectomies with circumferential reconstructions for thoracic spine fractures between 2004 and 2006 at SUMC were retrospectively reviewed. All surgeries were performed prone; operative technical details are reported. The preoperative and postoperative thoracic kyphotic angles were measured by Cobb angle evaluation using lateral chest plain films and magnetic resonance imaging. Other outcome measures evaluated included operative time, blood loss, neurologic and functional outcomes, postoperative pain, and treatment complications. RESULTS: The mean follow-up was 17.21 months (range: 9 to 30 mo) and preoperative kyphosis was 20.4 degrees (range: 6.0 to 57.9 degrees). The average postoperative kyphosis was 8.3 degrees (range: 1.8 to 2.67 degrees) and correction of kyphosis was 16.2 degrees (range: 6 to 30 degrees). The median estimated blood loss was 1411.67 mL (range: 300 to 4000 mL) and mean operating time was 4.8 hours (range: 2.8 to 8.6 h). Complications included 2 hardware failures requiring revision, 2 infections, and 1 dural laceration. Pain, Frankel Grade, and functional status were improved in all, except 1 preoperatively bedridden patient. CONCLUSIONS: Thoracic kyphotic correction is possible through a prone single-stage simultaneous anterior vertebrectomy and posterior reconstruction. Sufficient anterior and posterior correction of instability and fracture using the SUMC technique is possible with similar results to the traditional 2-stage approach.

Objective measures of functional impairment for degenerative diseases of the lumbar spine: a systematic review of the literature.

BACKGROUND CONTEXT: The accurate determination of a patient's functional status is necessary for therapeutic decision-making and to critically appraise treatment efficacy. Current subjective patient-reported outcome measure (PROM)-based assessments have limitations and can be complimented by objective measures of function. PURPOSE: To systematically review the literature and provide an overview on the available objective measures of function for patients with degenerative diseases of the lumbar spine. STUDY DESIGN/SETTING: Systematic review of the literature. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Two reviewers independently searched the PubMed, Web of Science, EMBASE, and SCOPUS databases for permutations of the words "objective," "assessment," "function," "lumbar," and "spine" including articles on human subjects with degenerative diseases of the lumbar spine that reported on objective measures of function, published until September 2018. Risk of bias was not assessed. No funding was received. The authors report no conflicts of interest. RESULTS: Of 2,389 identified articles, 82 were included in the final analysis. There was a significant increase of 0.12 per year in the number of publications dealing with objective measures of function since 1989 (95% CI 0.08-0.16, p<.001). Some publications studied multiple diagnoses and objective measures. The United States was the leading nation in terms of scientific output for objective outcome measures (n=21; 25.6%), followed by Switzerland (n=17; 20.7%), Canada, Germany, and the United Kingdom (each n=6; 7.3%). Our search revealed 21 different types of objective measures, predominantly applied to patients with lumbar spinal stenosis (n=67 publications; 81.7%), chronic/unspecific low back pain (n=28; 34.2%) and lumbar disc herniation (n=22; 26.8%). The Timed-Up-and-Go test was the most frequently applied measure (n=26 publications; 31.7%; cumulative number of reported subjects: 5,181), followed by the Motorized Treadmill Test (n=25 publications; 30.5%, 1,499 subjects) and with each n=9 publications (11.0%) the Five-Repetition Sit-To-Stand test (955 subjects), as well as accelerometry analyses (336 subjects). The reliability and validity of many of the less-applied objective measures was uncertain. There was profound heterogeneity in their application and interpretation of results. CONCLUSIONS: Clinical studies on patients with lumbar degenerative diseases increasingly employ objective measures of function, which offer high potential for improving the quality of outcome measurement in patient-care and research. This review provides an overview on available options. Our findings call for an agreement and standardization in terms of test selection, conduction and analysis to facilitate comparison of results across cohorts. PROSPERO REGISTRATION NUMBER: CRD42019122622.

Patient Satisfaction and Press Ganey Scores for Spine Versus Nonspine Neurosurgery Clinics.

STUDY DESIGN: Retrospective survey review. OBJECTIVE: We seek to evaluate satisfaction scores in patients seen in neurosurgical spine versus neurosurgical nonspine clinics. SUMMARY OF BACKGROUND DATA: The Press Ganey survey is a well-established metric for measuring hospital performance and patient satisfaction. These measures have important implications in setting hospital policy and guiding interventions to improve patient perceptions of care. METHODS: Retrospective Press Ganey survey review was performed to identify patient demographics and patient visit characteristics from January 1st, 2012 to October 10th, 2017 at Stanford Medical Center. A total of 40 questions from the Press Ganey survey were investigated and grouped in categories addressing physician and nursing care, personal concerns, admission, room, meal, operating room, treatment and discharge conditions, visitor accommodations and overall clinic assessment. Raw ordinal scores were converted to continuous scores of 100 for unpaired student t test analysis. We identified 578 neurosurgical spine clinic patients and 1048 neurosurgical nonspine clinic patients. RESULTS: Spine clinic patients reported lower satisfaction scores in aggregate (88.2 vs. 90.1; P=0.0014), physician (89.5 vs. 92.6; P=0.0002) and nurse care (91.3 vs. 93.4; P=0.0038), personal concerns (88.2 vs. 90.9; P=0.0009), room (81.0 vs. 83.1; P=0.0164), admission (90.8 vs. 92.6; P=0.0154) and visitor conditions (87.0 vs. 89.2; P=0.0148), and overall clinic assessment (92.9 vs. 95.5; P=0.005). CONCLUSIONS: This study is the first to evaluate the relationship between neurosurgical spine versus nonspine clinic with regards to patient satisfaction. The spine clinic cohort reported less satisfaction than the nonspine cohort in all significant questions on the Press Ganey survey. Our findings suggest that efforts should be made to further study and improve patient satisfaction in spine clinics. LEVEL OF EVIDENCE: Level III.

Reliability of the 6-minute walking test smartphone application.

OBJECTIVE: Objective functional measures such as the 6-minute walking test (6WT) are increasingly applied to evaluate patients with degenerative diseases of the lumbar spine before and after (surgical) treatment. However, the traditional 6WT is cumbersome to apply, as it requires specialized in-hospital infrastructure and personnel. The authors set out to compare 6-minute walking distance (6WD) measurements obtained with a newly developed smartphone application (app) and those obtained with the gold-standard distance wheel (DW). METHODS: The authors developed a free iOS- and Android-based smartphone app that allows patients to measure the 6WD in their home environment using global positioning system (GPS) coordinates. In a laboratory setting, the authors obtained 6WD measurements over a range of smartphone models, testing environments, and walking patterns and speeds. The main outcome was the relative measurement error (rME; in percent of 6WD), with |rME| < 7.5% defined as reliable. The intraclass correlation coefficient (ICC) for agreement between app- and DW-based 6WD was calculated. RESULTS: Measurements (n = 406) were reliable with all smartphone types in neighborhood, nature, and city environments (without high buildings), as well as with unspecified, straight, continuous, and stop-and-go walking patterns (ICC = 0.97, 95% CI 0.97-0.98, p < 0.001). Measurements were unreliable indoors, in city areas with high buildings, and for predominantly rectangular walking courses. Walking speed had an influence on the ME, with worse accuracy (2% higher rME) for every kilometer per hour slower walking pace (95% CI 1.4%-2.5%, p < 0.001). Mathematical adjustment of the app-based 6WD for velocity-dependent error mitigated the rME (p < 0.011), attenuated velocity dependence (p = 0.362), and had a positive effect on accuracy (ICC = 0.98, 95% CI 0.98-0.99, p < 0.001). CONCLUSIONS: The new, free, spine-specific 6WT smartphone app measures the 6WD conveniently by using GPS coordinates, empowering patients to independently determine their functional status before and after (surgical) treatment. Measurements of 6WD obtained for the target population under the recommended circumstances are highly reliable.

Assessment of Biomechanical Changes After Sacroiliac Joint Fusion by Application of the 3-Dimensional Motion Analysis Technique.

BACKGROUND: Sacroiliac (SI) joint motion is complex and is poorly understood overall. In this study we evaluated a new biomechanical method developed to provide more insight into SI joint movement and to elucidate biomechanical changes after SI joint fusion surgery in a one-leg standing model. METHODS: Eight lumbosacral cadaver specimens (L5-pelvis specimens, age 28-57 years, 6 female and 2 male) were used in this experiment. We analyzed the changes in range of motion (ROM) in single-plane motion and mobility in 3 groups of patients: intact, unilateral fusion, and bilateral fusion groups. For statistical analysis, we used repeated-measures analysis of variance to compare SI joint ROM among the 3 groups. iFuse implants were prepared using the standard posterior placement technique. Pure-moment multidirectional bending tests were performed in each direction (nutation and counternutation, axial rotation, and lateral bending). RESULTS: Average ROM in single-plane motion and mobility of the intact SI joint were 4.5 ± 3.3° and 4.8 ± 3.4°, respectively in nutation-counternutation; 2.9 ± 2.1° and 3.3 ± 2.3°, respectively, in axial rotation; and 1.5 ± 1.5° and 2.8 ± 2.5°, respectively, in lateral bending. We observed statistically significantly (P = 0.05) greater mobility in lateral moment testing than in single motion testing. Comparisons among the intact, unilateral fusion, and bilateral fusion groups showed statistically significant differences in the lateral moment test. CONCLUSIONS: This study suggests that our new biomechanical method for SI joint evaluation may provide improved insight into SI joint movement and biomechanical changes after SI joint fusion surgery in a one-leg standing model.

Radiographic Rate and Clinical Impact of Pseudarthrosis in Spine Radiosurgery for Metastatic Spinal Disease.

Purpose Pseudarthrosis within the spine tumor population is increased from perioperative radiation and complex stabilization for invasive and recurrent pathology. We report the radiographic and clinical rates of pseudarthrosis following multiple courses of instrumented fusion and perioperative stereotactic radiosurgery (SRS). Methods We performed a single institution review of 418 patients treated with non-isocentric SRS for spine between October 2002 and January 2013, identifying those with spinal instrumentation and greater than six months of follow-up. Surgical history, radiation planning, and radiographic outcomes were documented. Results Eleven patients who met criteria for inclusion underwent 21 sessions of spinal SRS and 16 instrumented operations. Radiographic follow-up was 48.9 months; 3/11 (27%) were with radiographic hardware failure, and one (9%) separate case ultimately warranted externalization due to tumor recurrence. SRS was administered to treat progression of disease in 12/21 (57%) procedures, and residual lesions in 7/11 (64%) procedures. Following first and second SRS, 8/11 (73%) and 2/7 (29%) patients were with symptomatic improvement, respectively. Conclusion Risk of pseudarthrosis following SRS for patients with oncologic spinal lesions will become increasingly apparent with the optimized management of and survival from spinal pathologies. We highlight how the need for local control outpaces the risk of instrumentation failure.

Successful extracorporeal life support after potentially fatal pulmonary oedema caused by inhalation of nitric and hydrofluoric acid fumes.

Two patients presented with potentially fatal pulmonary oedema after accidental exposure to nitric and hydrofluoric acid fumes during electroplating. Despite aggressive respiratory support, one succumbed to respiratory failure 3.5h after inhalation. The other patient also rapidly progressed to respiratory failure. Extracorporeal life support (ECLS) was started 5h after exposure at the ED. During ECLS, hypoxia improved, but pulmonary oedema shown by chest radiography became aggravated. N-Acetyl cysteine and calcium gluconate were given i.v. on the first day of admission and nebulised for 48 h after exposure. Pulmonary secretions were significantly reduced 24 h after the nebulising therapy began. Ultimately, the patient was discharged without serious pulmonary or neurological complications after 28 days of hospitalisation. In this case, early ECLS, nebulised antioxidant and antidote were available to treat potentially fatal pulmonary oedema after exposure to nitric and hydrofluoric acid fumes.

Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool.

OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.

3D patterned stem cell differentiation using thermo-responsive methylcellulose hydrogel molds.

Tissue-specific patterned stem cell differentiation serves as the basis for the development, remodeling, and regeneration of the multicellular structure of the native tissues. We herein proposed a cytocompatible 3D casting process to recapitulate this patterned stem cell differentiation for reconstructing multicellular tissues in vitro. We first reconstituted the 2D culture conditions for stem cell fate control within 3D hydrogel by incorporating the sets of the diffusible signal molecules delivered through drug-releasing microparticles. Then, utilizing thermo-responsivity of methylcellulose (MC), we developed a cytocompatible casting process to mold these hydrogels into specific 3D configurations, generating the targeted spatial gradients of diffusible signal molecules. The liquid phase of the MC solution was viscous enough to adopt the shapes of 3D impression patterns, while the gelated MC served as a reliable mold for patterning the hydrogel prepolymers. When these patterned hydrogels were integrated together, the stem cells in each hydrogel distinctly differentiated toward individually defined fates, resulting in the formation of the multicellular tissue structure bearing the very structural integrity and characteristics as seen in vascularized bones and osteochondral tissues.

Building an electronic health record integrated quality of life outcomes registry for spine surgery.

OBJECTIVE: Demonstrating the value of spine care requires adequate outcomes assessment. Long-term outcomes are best measured as overall improvement in quality of life (QOL) after surgical intervention. Present registries often require parallel data entry, introducing inefficiencies and limiting compliance. The authors detail the methodology of constructing an integrated electronic health record (EHR) system to collect QOL metrics and demonstrate the effect of data collection on routine clinical workflow. A streamlined approach to collecting QOL data can capture patient data without requiring dual data entry and without increasing clinic visit times. METHODS: Through extensive literature review, a combination of QOL assessments was selected, consisting of the Patient Health Questionnaire-2 and -9, Oswestry Disability Index, Neck Disability Index, and visual analog scale for pain. These metrics were used to provide assessment of QOL following spine surgery and were incorporated into standard clinic workflow by a multidisciplinary team of surgeons, advanced practice providers, and health care information technology specialists. A clinical dashboard tracking more than 25 patient variables was developed. Clinic flow was assessed and opportunities for improvement reviewed. Duration of clinic visits before and after initiation of QOL measure capture was recorded, with assessment of mean clinic visit times for the 12 months before and the 12 months after implementation. RESULTS: The integrated QOL capture was instituted for 3 spine surgeons in a tertiary care academic center. In the 12-month period prior to initiating collection of QOL data, 806 new patient visits were completed with an average visit time of 127.9 ± 51.5 minutes. In the 12 months after implementation, 1013 new patient visits were recorded, with 791 providing QOL measures with an average visit time of 117.0 ± 45.7 minutes. Initially the primary means of collecting patient outcome data was via paper form, with gradual transition to collection via entry into the electronic medical records system. To improve electronic data capture, paper forms were eliminated and an online portal used as part of the patient rooming process. This improved electronic capture to nearly 98% without decreasing the number of patients enrolled in the process. CONCLUSIONS: A systematic approach to collecting spine-related QOL data within an EHR system is feasible and offers distinct advantages over registries that require dual data entry. The process of data collection does not impact patients' clinical visit or providers' clinical workflow. This approach is scalable, and may form the foundation for a decentralized outcomes registry network.