Kambin's triangle and the position of the dorsal nerve root in the lumbar neural foramen.

INTRODUCTION: As a result of the increased utilization of neurosurgical arthroscopic techniques, investigations into population and sex-specific trends of anatomical considerations have become increasingly important. This study aimed to investigate and describe aspects of the neuroanatomical morphometry of lumbar spines in a cadaveric and magnetic resonance imaging (MRI) sample. MATERIALS AND METHODS: Twenty white adult (>18 years) cadavers (9 males; 11 females) were obtained under Ethical clearance. The lumbar regions were dissected and the position of the dorsal root ganglion (DRG) and dimensions of Kambin's triangle were determined. Twenty-six black adult (>18 years) MRI scans (17 males; 9 females) were obtained from an Academic Hospital and were used to determine the dimensions of the neural foramen and the DRGs within. RESULTS: The ganglia were mostly at the midline of the caudal pedicle. Similar to previous studies, the diagonal measurement from Kambin's triangle was the largest and the vertical measurement the shortest. Skeletal and soft-tissue measurements indicated distinct trends when moving caudolaterally in the spine. Soft-tissue parameters from the current study were within the upper limits of those from previous studies, whereas skeletal parameters were in agreement with those reported by previous authors. CONCLUSIONS: Results from this study suggest a variation of certain parameters between studies with varying population groups and therefore supports the need for and the importance of possible population-specific trends of anatomical parameters considered during surgical procedures.

Single- versus double-row repair for full-thickness rotator cuff tears using suture anchors. A systematic review and meta-analysis of basic biomechanical studies.

PURPOSE: The purpose of this study was to perform a systematic review and meta-analysis comparing single- and double-row biomechanical studies to evaluate load to failure, mode of failure and gap formation. MATERIALS AND METHODS: A systematic review of MEDLINE, Embase, Scopus and Google Scholar was performed from 1990 through 2016. The inclusion criteria were: documentation of ultimate load to failure, failure modes and documentation of elongation or gap formation. Studies were excluded if the study protocol did not use human specimens. Publication bias was assessed by funnel plot and Egger's test. The risk of bias was established using the Cochrane Collaboration's risk of bias tool. Heterogeneity was assessed using χ 2 and I 2 statistic. RESULTS: Eight studies were included. The funnel plot was asymmetric suggesting publication bias, which was confirmed by Egger's test (p = 0.04). The pooled estimate for load to failure demonstrated significant differences (SMD 1.228, 95% CI: 0.55-5.226, p = 0.006, I 2 = 60.47%), favouring double-row repair. There were no differences for failure modes. The pooled estimate for elongation/gap formation demonstrated significant differences (SMD 0.783, 95% CI: 0.169-1.398, p = 0.012, I 2 = 58.8%), favouring double-row repair. CONCLUSION: The results of this systematic review and meta-analysis suggest that double-row repair is able to tolerate a significantly greater load to failure. Gap formation was also significantly lower in the double-row repair group, but both of these findings should be interpreted with caution because of the inherent interstudy heterogeneity. LEVEL OF EVIDENCE: Systematic review and meta-analysis.

Feasibility of a Sprague???Dawley Rat Model for Investigating the Effects of Seated Whole-body Vibration.

Vehicular whole-body vibration (WBV) can have long-term adverse effects on human quality of life. Animal models can be used to study pathophysiologic effects of vibration. The goal of this study was to assess animal cooperation and well-being to determine the feasibility of a novel seated rat model for investigating the effects of WBV on biologic systems. Twenty-four male Sprague???Dawley rats were used. The experiment consisted of an acclimation phase, 2 training phases (TrP1 and TrP2), and a testing phase (TeP), including weekly radiographic imaging. During acclimation, rats were housed in pairs in standard cages without vibration. First, experimental (EG; n = 18) and control group 1 (C1; n = 3) rats were placed in a vibration apparatus without vibration, with increasing duration over 5 d during TrP1. EG rats were exposed to vertical random WBV that was increased in magnitude over 5 d during TrP2 until reaching the vibration signal used during TeP (15min, 0.7m??s-2 root mean square, unweighted). C1 rats were placed in the vibration apparatus but received no vibration during any phase. Control group 2 (C2; n = 3) rats remained in the home cages. Cooperation was evaluated with regard to rat-apparatus interactions and position compliance. Behavior, weight, and fecal glucocorticoid metabolite concentrations (fGCM) were used to evaluate animal well-being. We observed good cooperation and no behavioral patterns or weight loss between phases, indicating little or no animal stress. The differences in fGCM concentration between groups indicated that the EG rats had lower stress levels than the control rats in all phases except TrP1. Thus, this model elicited little or no stress in the conscious, unrestrained, seated rats.