Identifying Suspected Volume Conduction Contamination of External Anal Sphincter Motor Evoked Potentials in Lumbosacral Spine Surgery.

PURPOSE: Iatrogenic injury to sacral nerve roots poses significant quality of life issues for patients. Motor evoked potential (MEP) monitoring can be used for intraoperative surveillance of these important structures. We hypothesized that volume conducted depolarizations from gluteus maximus (GM) may contaminate external anal sphincter (EAS) MEP results during lumbosacral spine surgery. METHODS: Motor evoked potential from the EAS and medial GM in 40 patients were prospectively assessed for inter-muscle volume conduction during lumbosacral spine surgeries. Peak latency matching between the EAS and GM MEP recordings conditionally identified volume conduction (VC+) or no volume conduction (VC-). Linear regression and power spectral density analysis of EAS and medial GM MEP amplitudes were performed from VC+ and VC- data pairs to confirm intermuscle electrical cross-talk. RESULTS: Motor evoked potential peak latency matching identified putative VC+ in 9 of 40 patients (22.5%). Mean regression coefficients (r2) from peak-to-peak EAS and medial GM MEP amplitude plots were 0.83 ± 0.04 for VC+ and 0.34 ± 0.06 for VC- MEP (P < 0.001). Power spectral density analysis identified the major frequency component in the MEP responses. The mean frequency difference between VC+ EAS and medial GM MEP responses were 0.4 ± 0.2 Hz compared with 3.5 ± 0.6 Hz for VC- MEP (P < 0.001). CONCLUSIONS: Our data support using peak latency matching between EAS and GM MEP to identify spurious MEP results because of intermuscle volume conduction. Neuromonitorists should be aware of this possible cross-muscle conflict to avoid interpretation errors during lumbosacral procedures using EAS MEP.

On the Lift, Related Privacy Measures, and Applications to Privacy-Utility Trade-Offs.

This paper investigates lift, the likelihood ratio between the posterior and prior belief about sensitive features in a dataset. Maximum and minimum lifts over sensitive features quantify the adversary's knowledge gain and should be bounded to protect privacy. We demonstrate that max- and min-lifts have a distinct range of values and probability of appearance in the dataset, referred to as lift asymmetry. We propose asymmetric local information privacy (ALIP) as a compatible privacy notion with lift asymmetry, where different bounds can be applied to min- and max-lifts. We use ALIP in the watchdog and optimal random response (ORR) mechanisms, the main methods to achieve lift-based privacy. It is shown that ALIP enhances utility in these methods compared to existing local information privacy, which ensures the same (symmetric) bounds on both max- and min-lifts. We propose subset merging for the watchdog mechanism to improve data utility and subset random response for the ORR to reduce complexity. We then investigate the related lift-based measures, including ℓ1-norm, χ2-privacy criterion, and α-lift. We reveal that they can only restrict max-lift, resulting in significant min-lift leakage. To overcome this problem, we propose corresponding lift-inverse measures to restrict the min-lift. We apply these lift-based and lift-inverse measures in the watchdog mechanism. We show that they can be considered as relaxations of ALIP, where a higher utility can be achieved by bounding only average max- and min-lifts.

Beneficial Effects of Preoperative Exercise on the Outcomes of Lumbar Fusion Spinal Surgery.

Purpose: To determine whether there was an association between self-reported preoperative exercise and postoperative outcomes after lumbar fusion spinal surgery. Method: We performed a retrospective multivariable analysis of the prospective Canadian Spine Outcomes and Research Network (CSORN) database of 2,203 patients who had elective single-level lumbar fusion spinal surgeries. We compared adverse events and hospital length of stay between patients who reported regular exercise (twice or more per week) prior to surgery ("Regular Exercise") to those exercising infrequently (once or less per week) ("Infrequent Exercise") or those who did no exercise ("No Exercise"). For all final analyses, we compared the Regular Exercise group to the combined Infrequent Exercise or No Exercise group. Results: After making adjustments for known confounding factors, we demonstrated that patients in the Regular Exercise group had fewer adverse events (adjusted odds ratio 0.72; 95% CI: 0.57, 0.91; p = 0.006) and significantly shorter lengths of stay (adjusted mean 2.2 vs. 2.5 d, p = 0.029) than the combined Infrequent Exercise or No Exercise group. Conclusions: Patients who exercised regularly twice or more per week prior to surgery had fewer postoperative adverse events and significantly shorter hospital lengths of stay compared to patients that exercised infrequently or did no exercise. Further study is required to determine effectiveness of a targeted prehabilitation programme.

Objectif : déterminer s'il y avait une association entre les exercices préopératoires autodéclarés et les résultats postopératoires après une chirurgie de fusion lombaire. Méthodologie : analyse multivariable rétrospective de la base de données prospective Canadian Spine Outcomes and Research Network (CSORN) composée de 2 203 patients qui avaient subi une chirurgie de fusion lombaire univertébrale non urgente. Les chercheurs ont comparé les événements indésirables et la durée du séjour hospitalier entre les patients qui déclaraient faire de l'exercice régulier (au moins deux fois par semaine) avant l'opération (« exercice régulier ¼) à ceux qui n'en faisaient pas souvent (une fois ou moins par semaine; « exercice peu fréquent ¼) et qui n'en faisaient pas du tout (« absence d'exercice ¼). Pour toutes les analyses définitives, ils ont comparé le groupe qui faisait de l'exercice régulier aux groupes combinés d'exercice peu fréquent et d'absence d'exercice. Résultats : après correction pour tenir compte des facteurs confusionnels connus, les chercheurs ont démontré que les patients du groupe faisant de l'exercice régulier présentaient moins d'événements indésirables (rapport de cotes rajusté 0,72; IC à 95 % : 0,57, 0,91; p = 0,006) et leur séjour à l'hôpital était significativement plus court (moyenne corrigée 2,2 jours par rapport à 2,5 jours, p = 0,029) que dans le groupe combiné d'exercice peu fréquent et d'absence d'exercice. Conclusions : les patients qui faisaient de l'exercice régulièrement au moins deux fois par semaine avant l'opération présentaient moins d'événements indésirables après l'opération et étaient hospitalisés beaucoup moins longtemps que ceux qui ne faisaient pas beaucoup d'exercice ou n'en faisaient pas du tout. Il faudra réaliser d'autres études pour déterminer l'efficacité d'un programme de préréadaptation ciblé.

A Promiscuity Locus Confers Lotus burttii Nodulation with Rhizobia from Five Different Genera.

Legumes acquire access to atmospheric nitrogen through nitrogen fixation by rhizobia in root nodules. Rhizobia are soil-dwelling bacteria and there is a tremendous diversity of rhizobial species in different habitats. From the legume perspective, host range is a compromise between the ability to colonize new habitats, in which the preferred symbiotic partner may be absent, and guarding against infection by suboptimal nitrogen fixers. Here, we investigate natural variation in rhizobial host range across Lotus species. We find that Lotus burttii is considerably more promiscuous than Lotus japonicus, represented by the Gifu accession, in its interactions with rhizobia. This promiscuity allows Lotus burttii to form nodules with Mesorhizobium, Rhizobium, Sinorhizobium, Bradyrhizobium, and Allorhizobium species that represent five distinct genera. Using recombinant inbred lines, we have mapped the Gifu/burttii promiscuity quantitative trait loci (QTL) to the same genetic locus regardless of rhizobial genus, suggesting a general genetic mechanism for symbiont-range expansion. The Gifu/burttii QTL now provides an opportunity for genetic and mechanistic understanding of promiscuous legume-rhizobia interactions. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Peripheral leg ischemia detected via intraoperative neurophysiological monitoring during a multilevel complex anterior and posterior operation.

Intraoperative neurophysiologic monitoring is a technique utilized during spinal operations to minimize sensory and motor function morbidity. We herein report a case of a 73-year-old female with renal cell carcinoma and metastatic involvement of the cervical and thoracic spine, who underwent a multilevel complex anterior and posterior operation. Neurophysiological monitoring was able to localize the lower limb ischemia utilizing somatosensory evoked potentials. This prompted intraoperative investigation of the peripheral ischemia, and the patient was found to have an Angio-Seal device embolus in the right popliteal artery that dislodged from the right femoral artery.

A phantom and cadaveric study of radiostereometric analysis in posterior cervical and lumbar spinal fusion.

BACKGROUND CONTEXT: Detecting pseudarthrosis following spinal fusion is important for accurate diagnosis and treatment. Current diagnostic measures hold certain drawbacks. Radiostereometric analysis (RSA) is a radiographic technique with the capability to measure intervertebral segment changes and may be a novel way of assessing fusion. PURPOSE: The purpose of this work was to measure the accuracy and precision of RSA in instrumented posterior cervical and lumbar spinal fusion for measuring intervertebral movement. Further, to gain surgical practice with RSA in spine and determine optimal bead placements. STUDY DESIGN: Artificial bone and cadaveric spine models were used to simulate a 3-level cervical (C3-C6) and a 2-level (L4-S1) lumbosacral posterior spinal fusion to analyze bead placements and to measure RSA accuracy and precision. METHODS: Preliminary RSA bead placements were planned and measured in the artificial model. Secondary bead placements were adjusted slightly in the cadaveric model to consider additional fusion scenarios. Bead spread, detectability, and stability were measured to determine optimal placements. Translational and rotational precision of both models were measured. Accuracy was measured in the artificial spine model. Model-based RSA software was used for analysis. RESULTS: Optimal bead placements were found to be throughout the lateral mass of C3-C6 and in the spinous process, transverse process, and within the screw canal of L4-S1. Detectability was high among all segments. Spread was greater in L4-S1 than C3-C6 due to bead collinearity along the transverse axis of the cervical vertebrae. Translational and rotational RSA accuracy in cervical and lumbosacral regions ranged between 0.005 to 0.014 mm and 0.058 to 0.208°. Translational and rotational precision measured in the phantom models ranged 0.017 to 0.131 mm and 0.058 to 0.394° in C3-C6, and 0.086 to 0.191 mm and 0.200 to 0.369° in L4-S1. Translational and rotational precision measured in the cadaveric models ranged 0.054 to 0.548 mm and 0.148 to 1.386° in C3-C6, and 0.068 to 0.164 mm and 0.100 to 0.270° in L4-S1. CONCLUSIONS: RSA was found to be a feasible radiographic technique in C3-C6 and L4-S1 spinal fusion when measured in artificial and cadaveric models. Optimal bead placements were determined. Bead spread was shown to be better throughout the lumbar region than the cervical region due to anatomical size variations. RSA accuracy and precision were within acceptable RSA criteria. CLINICAL SIGNIFICANCE: The results from this work contribute to the accuracy, precision, and bead placements for studying RSA in cervical and lumbar spinal fusions. This work may further support the development of clinical studies to assess spinal fusion by evaluating postoperative intervertebral movement using RSA.

Emergency Department Clinician Experiences and Perceptions Regarding Noncardiac Chest Pain: A Cross-Sectional Survey. / Emergency Department Clinician Experiences and Perceptions Regarding Noncardiac Chest Pain: A Cross-Sectional Survey.

OBJECTIVES: The objectives of this study are to report the responses of emergency department (ED) clinicians regarding the characteristics and management of patients with noncardiac chest pain (NCCP) and to explore clinician experiences with the current standard of care and whether nonpharmacologic or nonsurgical referral options would be considered. METHODS: A cross-sectional survey was delivered to 40 ED clinicians from hospitals in Winnipeg, Manitoba from 2012 to 2013. Data were reduced descriptively and thematically summarized to assess the characteristics of patients with NCCP along with the responses of ED clinicians regarding the management of NCCP. RESULTS: The survey response was 27 (67.5% response rate). They reported that patients with NCCP comprised a considerable amount of ED care and are a variable and heterogeneous population. Respondents agreed (63.0%) that onsite and on-call providers for NCCP referral would assist in patient management. Further, ED clinicians (66.7%) would consider referring patients with NCCP to a nonpharmacologic, nonsurgical clinical research study. CONCLUSION: Clinicians in this study wanted better access to on-site referrals and outpatient clinics for patients experiencing NCCP after discharge and would consider nonpharmacologic or nonsurgical referral.

Incidence of Osteoporosis-Related Complications Following Posterior Lumbar Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVES: This study investigates the prevalence of adverse postsurgical events, or osteoporosis-related complications (ORCs), following spinal fusion. METHODS: Patients undergoing primary posterior thoracolumbar or lumbar fusion by 1 of 2 surgeons practicing at a single institution were analyzed from 2007 to 2014. ORCs were defined in one of the following categories: revision surgery, compression fracture, proximal junctional kyphosis, pseudarthrosis, or failure of instrumentation. Patients with a bone mineral density of the hips and/or spine performed within 1 year of the index procedure were included. Patients were stratified into normal bone density, osteopenia, and osteoporosis using WHO guidelines. Patients were excluded if they were younger than 18 years at the time of surgery, with infection, malignancy, skeletal dysplasia, neuromuscular disorders, concomitant or staged anterior-posterior procedure, or fusion performed because of trauma. RESULTS: Out of 140 patients included, the prevalence of normal bone density was 31.4% (44/140), osteopenia 58.6% (82/140), and osteoporosis 10.0% (14/140). There were no differences between groups for gender, age, body mass index, and interbody device rate. The overall prevalence of ORCs was 32.1% (45/140). By group, there was a prevalence of 22.7% (10/44), 32.9% (27/82), and 50.0% (7/14) for normal bone density, osteopenia, and osteoporosis, respectively. These differences were significantly higher for both the osteopenia and osteoporosis groups. CONCLUSIONS: Patients with T scores below -1.0 undergoing posterior lumbar fusion have an increased prevalence of ORCs. Consideration of bone density plays a crucial role in patient selection, medical management, and counseling patient expectations.

Improving spine surgical access, appropriateness and efficiency in metropolitan, urban and rural settings.

BACKGROUND: The Inter-professional Spine Assessment and Education Clinics (ISAEC) were developed to improve primary care assessment, education and management of patients with persistent or recurrent low back pain-related symptoms. This study aims to determine the effect of ISAEC on access for surgical assessment, referral appropriateness and efficiency for patients meeting a priori referral criteria in rural, urban and metropolitan settings. METHODS: We conducted a retrospective review of prospective data from networked ISAEC clinics in Thunder Bay, Hamilton and Toronto, Ontario. For patients meeting surgical referral criteria, wait times for surgical assessment, surgical referral-related magnetic resonance imaging (MRI) scans and appropriateness of referral were recorded. RESULTS: Overall 422 patients, representing 10% of all ISAEC patients in the study period, were referred for surgical assessment. The average wait times for surgical assessment were 5.4, 4.3 and 2.2 weeks at the metropolitan, urban and rural centres, respectively. Referral MRI usage for the group decreased by 31%. Of the patients referred for formal surgical assessment, 80% had leg-dominant pain and 96% were deemed appropriate surgical referrals. CONCLUSION: Contrary to geographic concentration of health care resources in metropolitan settings, the greatest decrease in wait times was achieved in the rural setting. A networked, shared-cared model of care for patients with low back pain-related symptoms significantly improved access for surgical assessment despite varying geographic practice settings and barriers. The greatest reductions were noted in the rural setting. In addition, significant improvements in referral appropriateness and efficiency were achieved compared with historical reports across all sites.

CONTEXTE: Les cliniques interprofessionnelles d'évaluation de la colonne vertébrale et d'éducation (Inter-professional Spine Assessment and Education Clinics [ISAEC]) ont été mises sur pied pour améliorer les soins primaires d'évaluation, d'éducation et de prise en charge des patients atteints de symptômes persistants ou récurrents de lombalgie. Cette étude a pour but d'évaluer l'effet des ISAEC sur l'accès à une évaluation chirurgicale et sur la pertinence et l'efficacité de la référence des patients en milieux ruraux, urbains et métropolitains répondant a priori aux critères de référence. MÉTHODES: Nous avons mené une étude rétrospective de données prospectives issues de cliniques du réseau des ISAEC situées à Thunder Bay, à Hamilton et à Toronto, en Ontario. Nous avons retenu pour l'étude les patients répondant aux critères de référence en chirurgie; pour chacun de ces patients, nous avons consigné le temps d'attente pour obtenir une évaluation chirurgicale, les images obtenues par résonance magnétique (IRM) aux fins de référence et la pertinence de la référence. RÉSULTATS: Au total, 422 patients, soit 10 % des patients des ISAEC au cours de la période étudiée, ont été dirigés en évaluation chirurgicale. Les temps d'attente moyens pour obtenir une évaluation chirurgicale étaient de 5,4 semaines, de 4,3 semaines et de 2,2 semaines dans les centres métropolitains, urbains et ruraux, respectivement. Le recours à l'IRM aux fins de référence a diminué de 31 % par rapport à la situation initiale. Parmi les patients référés en évaluation chirurgicale formelle, 80 % présentaient une douleur principalement localisée dans les jambes. La référence de 96 % des patients a été jugée adéquate. CONCLUSION: Même si les ressources en soins de santé sont concentrées en milieu métropolitain, c'est le milieu rural qui a connu la plus grande baisse du temps d'attente. La mise sur pied d'un modèle de soins partagés en réseau pour les patients aux prises avec des symptômes de lombalgie a amélioré l'accès aux évaluations chirurgicales de façon significative, malgré la variété géographique des milieux de pratique et les divers obstacles rencontrés. Les baisses les plus importantes ont été observées en milieu rural. De plus, des améliorations significatives de la pertinence et de l'efficacité des références ont été observées lors de la comparaison avec les rapports antérieurs, pour tous les sites de l'étude.

Do Lumbar Decompression and Fusion Patients Recall Their Preoperative Status?: A Cohort Study of Recall Bias in Patient-Reported Outcomes.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To characterize the accuracy of patient recollection of preoperative symptoms after lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Although patient-reported outcomes have become important in the evaluation of spine surgery patients, the accuracy of patient recall remains unknown. METHODS: Patients undergoing lumbar decompression with or without fusion were enrolled. Back and leg Numeric Pain Scores and Oswestry Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at a minimum of 1 year after surgery. Actual and recalled scores were compared using paired t tests and relations were quantified using Pearson correlation coefficients. Multivariable linear regression was used to identify factors that affected recollection. RESULTS: Sixty-two patients with a mean age of 66.1 years were included. Compared to their preoperative scores, patients showed significant improvement in back pain (mean difference [MD] = -3.2, 95% CI -4.0 to -2.4), leg pain (MD -3.3, 95% CI -4.3 to -2.2), and disability (MD -25.0%, 95% CI -28.7 to -19.6). Patient recollection of preoperative status was significantly more severe than actual for back pain (MD +2.3, 95% CI 1.5-3.2), leg pain (MD +1.8, 95% CI 0.9-2.7), and disability (MD +9.6%, 95% CI 5.6-14.0). No significant correlation between actual and recalled scores with regards to back (r = 0.18) or leg (r = 0.24) pain and only moderate correlation with disability (r = 0.44) were seen. This was maintained across age, sex, and time between date of surgery and recollection. More than 40% of patients switched their predominant symptom from back pain to leg pain or leg pain to back pain on recall. CONCLUSION: Relying on patient recollection does not provide an accurate measure of preoperative status after lumbar spine surgery. Recall bias indicates the importance of obtaining true baseline scores and patient-reported outcomes prospectively and not retrospectively. LEVEL OF EVIDENCE: 2.

Relationship between sleep, pain, and disability in patients with spinal pathology.

OBJECTIVE: To characterize sleep and its relationship with disability and pain in patients with spine pathology. DESIGN: A survey study. SETTING: A university-based hospital spine clinic. PARTICIPANTS: Subjects (N=121) with mixed-etiology spine pathology. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Self-reported disability (Oswestry Disability Index [ODI]), back and leg pain intensity, the effect of back or leg pain on function, and sleep (Pittsburgh Sleep Quality Index [PSQI]) assessments were completed. RESULTS: Severe disability was evident with a mean ODI ± SD of 54.9±14, with mean pain intensities ± SD of 50±30 mm and 54±27 mm of 100mm for the leg and back, respectively. The mean PSQI ± SD was 10.4±5.3, with 87% of participants scoring greater than the sleep-disordered threshold of 5. PSQI was correlated to ODI (r=.53, P<.001), and ODI without the sleep component (r=.47, P<.001). Six of the subscales of PSQI were all also significantly correlated to ODI (.25

Training emotional intelligence improves both emotional intelligence and depressive symptoms in inpatients with borderline personality disorder and depression.

OBJECTIVE: Borderline personality disorder (BPD) is defined as a pervasive pattern of instability in emotion, mood and interpersonal relationships, with a comorbidity between PBD and depressive disorders (DD). A key competence for successful management of interpersonal relationships is emotional intelligence (EI). Given the low EI of patients suffering from BPD, the present study aimed at investigating the effect on both emotional intelligence and depression of training emotional intelligence in patients with BPD and DD. METHODS: A total of 30 inpatients with BPD and DD (53% females; mean age 24.20 years) took part in the study. Patients were randomly assigned either to the treatment or to the control group. Pre- and post-testing 4 weeks later involved experts' rating of depressive disorder and self-reported EI. The treatment group received 12 sessions of training in components of emotional intelligence. RESULTS: Relative to the control group, EI increased significantly in the treatment group over time. Depressive symptoms decreased significantly over time in both groups, though improvement was greater in the treatment than the control group. CONCLUSION: For inpatients suffering from BPD and DD, regular skill training in EI can be successfully implemented and leads to improvements both in EI and depression. Results suggest an additive effect of EI training on both EI and depressive symptoms.

Revision total knee arthroplasty for component malrotation is highly beneficial: a case control study.

Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. We reviewed 24 patients who had TKA revision due to component malrotation as the only objective abnormality. Mean combined component rotation was 6.8° excessive internal rotation, as documented by computed tomography. Twenty-four matched control patients had TKA revision due to aseptic loosening. Mean follow-up was 37 months. Preoperative Knee Society Score improved by 49 points at 6 months postoperatively for the malrotation patients and by 39 for the loosening patients. At last follow-up, Knee Society Score was 80 for the malrotation group and 75 for the loosening group. We recommend the use of computed tomography scans in evaluation of all patients with early painful TKAs and no objective evidence of infection. When component malrotation is demonstrated, early revision should be considered.