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Background: Pedicle screw placement during spine fusion is physically and mentally demanding for surgeons. Consequently, spine surgeons can become fatigued, which has implications for both patient safety and surgeon well-being., Purpose: We sought to assess the cognitive workload of surgeons placing pedicle screws using robotic-assisted navigation compared with fluoroscopic and computed tomography (CT)-assisted placement., Methods: We performed a nonrandomized prospective controlled trial to compare the cognitive workload of 3 surgeons performing single-level minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using robotic, CT, or fluoroscopic navigation on 25 patients (15 in the robotic navigation group and 10 in the nonrobotic group). Immediately after each procedure, surgeons submitted the National Aeronautics and Space Administration-Task Load Index (NASA-TLX), which has 6 subscales: mental demands, physical demands, temporal demands, performance, effort, and frustration. Four tasks associated with pedicle screw placement were assessed independently: (1) screw planning, (2) calibrating robot/obtaining imaging/registration, (3) pedicle cannulation, and (4) screw placement. Patient demographics and surgical characteristics were obtained and reviewed., Results: Surgeons' self-reported cognitive workload was significantly reduced when using robotic-assisted navigation versus CT/fluoroscopic navigation. Workload was reduced for screw planning, pedicle cannulation, and screw placement. In addition, there were significant reductions in each subdomain for these 3 tasks, encompassing mental demand, physical demand, temporal demand, effort, and frustration with improved task performance., Conclusions: This study found significant reductions in mental workload with improved perceived performance for robotic-assisted pedicle screw placement compared with fluoroscopic and CT-navigation techniques. Lowering the cognitive burden associated with screw placement may allow surgeons to address the remainder of the operative case with less decision fatigue, prevent complications, and increase surgeon wellness., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: KWM reports relationships with NIH, OREF, SRS, Johnson & Johnson, GE Health, and Sustain Surgical. SQ reports relationships with Viseon, Tissue Differentiation Intelligence, HS2, Minimally Invasive Spine Study Group, Stryker, SpineGuard, Globus Medical, Surgalign, Lifelink.com, Spinal Simplicity, Contemporary Spine Surgery, NASS, Annals of Translational Medicine, HSS Journal, Society of Minimally Invasive Spine Surgery (SMISS), Lumbar Spine Research Society (LSRS), Cervical Spine Research Society (CSRS), Association of Bone and Joint Surgeons (ABJS), and International Society for the Advancement of Spine Surgery (ISASS). SI reports relationships with Innovasis, HS2, Stryker, Healthgrades, and Globus Medical. The other authors declare no potential conflicts of interest., (© The Author(s) 2024.)

Background: Multiple animal models have previously been utilized to investigate anterior fusion techniques, but a mouse model has yet to be developed. The purpose of this study was to develop murine anterior interbody and posterolateral fusion techniques., Methods: Mice underwent either anterior interbody or posterolateral spinal fusion. A protocol was developed for both procedures, including a description of the relevant anatomy. Samples were subjected to micro-computed tomography to assess fusion success and underwent biomechanical testing with use of 4-point bending. Lastly, samples were fixed and embedded for histologic evaluation., Results: Surgical techniques for anterior interbody and posterolateral fusion were developed. The fusion rate was 83.3% in the anterior interbody model and 100% in the posterolateral model. Compared with a control, the posterolateral model exhibited a greater elastic modulus. Histologic analysis demonstrated endochondral ossification between bridging segments, further confirming the fusion efficacy in both models., Conclusions: The murine anterior interbody and posterolateral fusion models are efficacious and provide an ideal platform for studying the molecular and cellular mechanisms mediating spinal fusion., Clinical Relevance: Given the extensive genetic tools available in murine disease models, use of fusion models such as ours can enable determination of the underlying genetic pathways involved in spinal fusion., Competing Interests: Disclosure: This study was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (NIH) under award number T32-AR078751 (K.W.M.) and by NIH awards DP5OD021351 and R01AR075585 (M.B.G.). This study is also based on research supported by Pershing Square Sohn Cancer Research Alliance and Pershing Square Foundation MIND Prize awards to M.B.G. M.B.G. holds a Career Award for Medical Scientists from the Burroughs Welcome Fund. S.I. is supported by the Kellen Scholar Award. J.S. is supported by a Children’s Tumor Foundation Young Investigator Award (CTF-2023-01-005; https://doi.org/10.48105/CTF.CTF-2023-01-005.pc.gr.172007 ). A.R.Y. is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under award number T32-AR071302-07. S.B. is supported by a National Research Foundation of Korea award funded by the Ministry of Education (NRF-2021R1A6A3A14038667), the Arthritis Grant Program from the Arthritis National Research Foundation (1065843), and Weill Cornell Medicine JumpStart Awards (Year 2022). S.D. is supported by an NIH K99 grant (DE031819-01), a Department of Defense grant (W81XWH-22-PRMRP-DA), and Weill Cornell Medicine JumpStart Awards (Year 2019). The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H833 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Study Design: Retrospective cohort study., Objective: The objectives of the present study were to (1) define telemedicine utilization rates during and after the initial height of the COVID-19 lockdown period and (2) determine patient satisfaction with telemedicine during and after the initial height of the COVID-19 lockdown period for spine patients at an orthopedic specialty hospital., Summary of Background Data: Previous studies have shown high patient satisfaction with telemedicine during the initial height of the COVID-19 pandemic. However, there exists limited data about spine telemedicine utilization and patient satisfaction after the reopening of in-person office visits and the easing of restrictions on elective surgical care., Materials and Methods: All patients who had an in-person or telemedicine visit at an urban tertiary specialty hospital from April 1, 2020 to April 15, 2021 were identified. Rates of overall telemedicine utilization over time were delineated. Patient satisfaction with telemedicine, as assessed through a series of questionnaires, was also evaluated over time., Results: Overall, 60,368 patients were identified. Of these, 19,568 patients (32.4%) had telemedicine visit. During the peak initial coronavirus lockdown period, the rate of overall telemedicine utilization, on average, was greater than 90%. After the peak period, the rate of overall telemedicine utilization on average was at ~29% of all visits per month. The percentage of patients who would have been definitely comfortable if the telemedicine visit had been in-person increased over the entire study period ( P <0.001). Despite this, patient satisfaction based on survey responses remained statistically similar throughout the study period ( P >0.05)., Conclusion: The rate of telemedicine utilization in spine patients remains high, at ~one-third of all visits, even after the initial peak coronavirus lockdown period. In addition, patient satisfaction with telemedicine remained consistent throughout the study period, regardless of pandemic restrictions on in-person visits., Level of Evidence: 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Navigation and robotic technologies have emerged as an alternative option to conventional freehand techniques for pedicle screw insertion. However, the effectiveness of these technologies in reducing the perioperative complications of spinal fusion surgery remains limited due to the small cohort size in the existing literature., Purpose: To investigate whether utilization of robotically navigated pedicle screw insertion can reduce the perioperative complications of spinal fusion surgery-including reoperations-with a sizeable cohort., Study Design: Retrospective study., Patient Sample: Patients who underwent primary lumbar fusion surgery between 2019 and 2022., Outcome Measures: Perioperative complications including readmission, reoperation, its reasons, estimated blood loss, operative time, and length of hospital stay., Methods: Patients' data were collected including age, sex, race, body mass index, upper-instrumented vertebra, lower-instrumented vertebra, number of screws inserted, and primary procedure name. Patients were classified into the following two groups: freehand group and robot group. The variable-ratio greedy matching was utilized to create the matched cohorts by propensity score and compared the outcomes between the two group., Results: A total of 1,633 patients who underwent primary instrumented spinal lumbar fusion surgery were initially identified (freehand 1,286; robot 347). After variable ratio matching was performed with age, sex, body mass index, fused levels, and upper instrumented vertebrae level, 694 patients in the freehand group and 347 patients in robot groups were selected. The robot group showed less estimated blood loss (418.9±398.9 vs 199.2±239.6 ml; p<.001), shorter LOS (4.1±3.1 vs 3.2±3.0 days; p<.001) and similar operative time (212.5 vs 222.0 minutes; p=.151). Otherwise, there was no significant difference in readmission rate (3.6% vs 2.6%; p=.498), reoperation rate (3.2% vs 2.6%; p=.498), and screw malposition requiring reoperation (five cases, 0.7% vs one case, 0.3%; p=1.000)., Conclusions: Perioperative complications requiring readmission and reoperation were similar between fluoroscopy guided freehand and robotic surgery. Robot-guided pedicle screw insertion can enhance surgical efficiency by reducing intraoperative blood loss and length of hospital stay without extending operative time., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: A pitcher's ability to achieve pitch location precision after a complex series of motions is of paramount importance. Kinematics have been used in analyzing performance benefits like ball velocity, as well as injury risk profile; however, prior utilization of such data for pitch location metrics is limited., Objective: To develop a pitch classifier model utilizing machine learning algorithms to explore the potential relationships between kinematic variables and a pitcher's ability to throw a strike or ball., Methods: This was a descriptive laboratory study involving professional baseball pitchers (n = 318) performing pitching tests under the setting of 3D motion-capture (480 Hz). Main outcome measures included accuracy, sensitivity, specificity, F1 score, positive predictive value (PPV), and negative predictive value (NPV) of the random forest model., Results: The optimized random forest model resulted in an accuracy of 70.0 %, sensitivity of 70.3 %, specificity of 48.5 %, F1 equal to 80.6 %, PPV of 94.3 %, and a NPV of 11.6 %. Classification accuracy for predicting strikes and balls achieved an area under the curve of 0.67. Kinematics that derived the highest % increase in mean square error included: trunk flexion excursion(4.06 %), pelvis obliquity at foot contact(4.03 %), and trunk rotation at hand separation(3.94 %). Pitchers who threw strikes had significantly less trunk rotation at hand separation(p = 0.004) and less trunk flexion at ball release(p = 0.003) compared to balls. The positive predictive value for determining a strike was within an acceptable range, while the negative predictive value suggests if a pitch was determined as a ball, the model was not adequate in its prediction., Conclusions: Kinematic measures of pelvis and trunk were crucial determinants for the pitch classifier sequence, suggesting pitcher kinematics at the proximal body segments may be useful in determining final pitch location., Competing Interests: The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article., (© 2023 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Bone morphogenetic protein (BMP) gene delivery to Lewis rat lumbar intervertebral discs (IVDs) drives bone formation anterior and external to the IVD, suggesting the IVD is inhospitable to osteogenesis. This study was designed to determine if IVD destruction with a proteoglycanase, and/or generating an IVD blood supply by gene delivery of an angiogenic growth factor, could render the IVD permissive to intra-discal BMP-driven osteogenesis and fusion. Surgical intra-discal delivery of naïve or gene-programmed cells (BMP2/BMP7 co-expressing or VEGF 165 expressing) +/- purified chondroitinase-ABC (chABC) in all permutations was performed between lumbar 4/5 and L5/6 vertebrae, and radiographic, histology, and biomechanics endpoints were collected. Follow-up anti-sFlt Western blotting was performed. BMP and VEGF/BMP treatments had the highest stiffness, bone production and fusion. Bone was induced anterior to the IVD, and was not intra-discal from any treatment. chABC impaired BMP-driven osteogenesis, decreased histological staining for IVD proteoglycans, and made the IVD permissive to angiogenesis. A soluble fragment of VEGF Receptor-1 (sFlt) was liberated from the IVD matrix by incubation with chABC, suggesting dysregulation of the sFlt matrix attachment is a possible mechanism for the chABC-mediated IVD angiogenesis we observed. Based on these results, the IVD can be manipulated to foster vascular invasion, and by extension, possibly osteogenesis.

Study Design: Retrospective cohort study., Objective: The purpose of this study was to assess trends in disparities in utilization of hospital outpatient departments (HOPDs) and ambulatory surgical centers (ASCs) for outpatient ACDF (OP-ACDF) between White, Black, Hispanic, and Asian/Pacific Islander patients from 2015 to 2018 in New York State., Summary of Background Data: Racial and ethnic disparities within the field of spine surgery have been thoroughly documented. To date, it remains unknown how these disparities have evolved in the outpatient setting alongside the rapid emergence of ASCs and whether restrictive patterns of access to these outpatient centers exist by race and ethnicity., Materials and Methods: We conducted a retrospective review from 2015 to 2018 using the Healthcare Cost and Utilization Project (HCUP) New York State Ambulatory Database. Differences in utilization rates for OP-ACDF were assessed and trended over time by race and ethnicity for both HOPDs and freestanding ASCs. Poisson regression was used to evaluate the association between utilization rates for OP-ACDF and race/ethnicity., Results: Between 2015 and 2018, Black, Hispanic, and Asian patients were less likely to undergo OP-ACDF compared with White patients in New York State. However, the magnitude of these disparities lessened over time, as Black, Hispanic, and Asian patients had greater relative increases in utilization of HOPDs and ASCs for ACDF when compared with White patients ( Ptrend <0.001). The magnitude of the increase in freestanding ASC utilization was such that minority patients had higher ACDF utilization rates in freestanding ASCs by 2018 ( P <0.001)., Conclusions: We found evidence of improving racial disparities in the relative utilization of outpatient ACDF in New York State. The increase in access to outpatient ACDF appeared to be driven by an increasing number of patients undergoing ACDF in freestanding ASCs in large metropolitan areas. These improving disparities are encouraging and contrast previously documented inequalities in inpatient spine surgery., Level of Evidence: III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Vertebral bone is subject to a distinct set of disease processes from long bones, including a much higher rate of solid tumour metastases 1-4 . The basis for this distinct biology of vertebral bone has so far remained unknown. Here we identify a vertebral skeletal stem cell (vSSC) that co-expresses ZIC1 and PAX1 together with additional cell surface markers. vSSCs display formal evidence of stemness, including self-renewal, label retention and sitting at the apex of their differentiation hierarchy. vSSCs are physiologic mediators of vertebral bone formation, as genetic blockade of the ability of vSSCs to generate osteoblasts results in defects in the vertebral neural arch and body. Human counterparts of vSSCs can be identified in vertebral endplate specimens and display a conserved differentiation hierarchy and stemness features. Multiple lines of evidence indicate that vSSCs contribute to the high rates of vertebral metastatic tropism observed in breast cancer, owing in part to increased secretion of the novel metastatic trophic factor MFGE8. Together, our results indicate that vSSCs are distinct from other skeletal stem cells and mediate the unique physiology and pathology of vertebrae, including contributing to the high rate of vertebral metastasis., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Craniosynostosis is a group of disorders of premature calvarial suture fusion. The identity of the calvarial stem cells (CSCs) that produce fusion-driving osteoblasts in craniosynostosis remains poorly understood. Here we show that both physiologic calvarial mineralization and pathologic calvarial fusion in craniosynostosis reflect the interaction of two separate stem cell lineages; a previously identified cathepsin K (CTSK) lineage CSC 1 (CTSK + CSC) and a separate discoidin domain-containing receptor 2 (DDR2) lineage stem cell (DDR2 + CSC) that we identified in this study. Deletion of Twist1, a gene associated with craniosynostosis in humans 2,3 , solely in CTSK + CSCs is sufficient to drive craniosynostosis in mice, but the sites that are destined to fuse exhibit an unexpected depletion of CTSK + CSCs and a corresponding expansion of DDR2 + CSCs, with DDR2 + CSC expansion being a direct maladaptive response to CTSK + CSC depletion. DDR2 + CSCs display full stemness features, and our results establish the presence of two distinct stem cell lineages in the sutures, with both populations contributing to physiologic calvarial mineralization. DDR2 + CSCs mediate a distinct form of endochondral ossification without the typical haematopoietic marrow formation. Implantation of DDR2 + CSCs into suture sites is sufficient to induce fusion, and this phenotype was prevented by co-transplantation of CTSK + CSCs. Finally, the human counterparts of DDR2 + CSCs and CTSK + CSCs display conserved functional properties in xenograft assays. The interaction between these two stem cell populations provides a new biologic interface for the modulation of calvarial mineralization and suture patency., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Purpose: Adolescent idiopathic scoliosis (AIS) is a deformity of the spine that results in external asymmetry of the torso in the shoulder, waist, and rib hump. Several patient reported outcome measures (PROMS) including the Trunk Appearance Perception Scale (TAPS) and SRS-22r self-image domain are used to measure the patient's self-perception. The purpose of this study is to investigate the relationship between objective surface topographic measurements of the torso to subjective patient self-perception., Methods: 131 AIS subjects and 37 controls participated in this study. All subjects completed TAPS and SRS-22r PROMS followed by whole body 3d surface topographic scanning. An automated analysis pipeline was used to compute 57 measurements. Multivariate linear models were developed to predict TAPS and SRS-22r self-image using each unique combination of 3 parameters and leave one out validation where the best combinations were selected., Results: Back surface rotation, waist crease vertical asymmetry and rib prominence volume were most predictive of TAPS. The final predicted TAPS values from leave one out cross validation was correlated to ground truth TAPS scores with an R value of 0.65. Back surface rotation, silhouette centroid deviation, and shoulder normal asymmetry were most predictive of SRS-22r self-image with a correlation of R = 0.48., Conclusion: Surface topographic measurements of the torso are correlated to TAPS and SRS-22r self-image scores in AIS patients and controls, with TAPS exhibiting a stronger relationship, better reflecting the patient's external asymmetries., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Identifying genetic risk factors for spinal disorders may lead to knowledge regarding underlying molecular mechanisms and the development of new treatments., Methods: Cases of lumbar spondylolisthesis, spinal stenosis, degenerative disc disease, and pseudarthrosis after spinal fusion were identified from the UK Biobank. Controls were patients without the diagnosis. Whole-genome regressions were used to test for genetic variants potentially implicated in the occurrence of each phenotype. External validation was performed in FinnGen., Results: A total of 389,413 participants were identified from the UK Biobank. A locus on chromosome 2 spanning GFPT1, NFU1, AAK1, and LOC124906020 was implicated in lumbar spondylolisthesis. Two loci on chromosomes 2 and 12 spanning genes GFPT1, NFU1, and PDE3A were implicated in spinal stenosis. Three loci on chromosomes 6, 10, and 15 spanning genes CHST3, LOC102723493, and SMAD3 were implicated in degenerative disc disease. Finally, 2 novel loci on chromosomes 5 and 9, with the latter corresponding to the LOC105376270 gene, were implicated in pseudarthrosis. Some of these variants associated with spinal stenosis and degenerative disc disease were also replicated in FinnGen., Conclusions: This study revealed nucleotide variations in select genetic loci that were potentially implicated in 4 different spinal pathologies, providing potential insights into the pathological mechanisms., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/H454)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Although ball velocity has often been associated with increased kinetics at the upper extremity and risk of injury in youth and adolescent pitchers, it is unclear if the performance metric pitch location consistency has any positive or negative associations with pitching kinetics., Methods: High school pitchers (n = 59) pitched 8-12 fastballs using 3D motion capture (480 Hz). Pitchers were divided into high-consistency (HiCon) and low-consistency (LoCon) groups based on the absolute center deviation of each pitcher's pitch to the center of the pitcher's mean pitch location. Ninety-five percent confidence ellipses with major and minor radii were constructed, and kinematics and kinetics were compared between groups., Results: Compared with LoCon pitchers, HiCon pitchers had decreased lead hip flexion at elbow extension (40° ± 12° vs. 52° ± 13°, respectively, P = .008), and at foot contact, decreased back hip extension (-1° ± 10° vs. -10° ± 13°, respectively, P = .038) and increased back hip internal rotation (9° ± 15° vs. -2° ± 15°, respectively, P = .043). LoCon pitchers achieved maximum lead hip flexion earlier in the pitch (61.3% ± 23.2% vs. 75.8% ± 15.1%, respectively, P = .039). A multiregression model predicted 0.49 of variance in pitch location consistency using kinematic inputs., Discusssion and Conclusion: Pitchers who differ in pitch location consistency outcomes do not appear to demonstrate physiologically unsafe kinematics. High school pitchers who strive for improved pitch consistency can consider adjusting parameters of hip kinematics during early portions of the pitch., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Adolescent idiopathic scoliosis results in three dimensional changes to a patient’s body, which may change a patient’s range of motion. Surface topography is an emerging technology to evaluate three dimensional parameters in patients with scoliosis. The goal of this paper is to introduce novel and reliable surface topographic measurements for the assessment of global coronal and sagittal range of motion of the spine in adolescents, and to determine if these measurements can distinguish between adolescents with lumbar scoliosis and those without scoliosis. Methods: This study is a retrospective cohort study of a prospectively collected registry. Using a surface topographic scanner, a finger to floor and lateral bending scans were performed on each subject. Inter- and intra-rater reliabilities were assessed for each measurement. ANOVA analysis was used to test comparative hypotheses. Results: Inter-rater reliability for lateral bending fingertip asymmetry (LBFA) and lateral bending acromia asymmetry (LBAA) displayed poor reliability, while the coronal angle asymmetry (CAA), coronal angle range of motion (CAR), forward bending finger to floor (FBFF), forward bending acromia to floor (FBAF), sagittal angle (SA), and sagittal angle normalized (SAN) demonstrated good to excellent reliability. There was a significant difference between controls and lumbar scoliosis patients for LBFA, LBAA, CAA and FBAF (p-values < 0.01). Conclusion: Surface topography yields a reliable and rapid process for measuring global spine range of motion in the coronal and sagittal planes. Using these tools, there was a significant difference in measurements between patients with lumbar scoliosis and controls. In the future, we hope to be able to assess and predict perioperative spinal mobility changes.

Study Design: Prospective randomized placebo controlled animal trial., Objective: Determine the effect of daily subcutaneous abaloparatide injection on the intervertebral fusion rate in rabbits undergoing posterolateral fusion., Study of Background Data: Despite the wide utilization of spine fusion, pseudarthrosis remains prevalent, and results in increased morbidity. Abaloparatide is a novel analog of parathyroid hormone-related peptide (1-34) and has shown efficacy in a rat posterolateral spine fusion model to increase fusion rates. The effect of abaloparatide on the fusion rate in a larger animal model remains unknown., Materials and Methods: A total of 24 skeletally mature New Zealand White male rabbits underwent bilateral posterolateral spine fusion. Following surgery, the rabbits were randomized to receive either saline as control or abaloparatide subcutaneous injection daily. Specimens underwent manual assessment of fusion, radiographic analysis with both x-ray and high-resolution peripheral quantitative computed tomography, and biomechanical assessment., Results: Rabbits that received abaloparatide had a 100% (10/10) fusion rate compared with 45% (5/11) for controls ( P <0.02) as assessed by manual palpation. Radiographic analysis determined an overall mean fusion score of 4.17±1.03 in the abaloparatide group versus 3.39±1.21 for controls ( P <0.001). The abaloparatide group also had a greater volume of bone formed with a bone volume of 1209±543 mm 3 compared with 551±152 mm 3 ( P <0.001) for controls. The abaloparatide group had significantly greater trabecular bone volume fraction and trabecular thickness and lower specific bone surface and connectivity density in the adjacent levels when compared with controls. Abaloparatide treatment did not impact trabecular number or separation. There were no differences in biomechanical testing in flexion, extension, or lateral bending ( P >0.05) between groups., Conclusions: Abaloparatide significantly increased the fusion rate in a rabbit posterolateral fusion model as assessed by manual palpation. In addition, there were marked increases in the radiographic evaluation of fusion., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: A retrospective cohort comparison study., Objective: To compare perioperative outcomes, radiographic parameters, and patient-reported outcome measures (PROMs) between minimally invasive unilateral laminotomy with bilateral decompression (MIS-ULBD) versus MIS transforaminal lumbar interbody fusion (MIS-TLIF) for treatment of low-grade lumbar degenerative spondylolisthesis., Summary of Background Data: While lumbar degenerative spondylolisthesis is a common condition, optimal surgical treatment remains controversial. Newer MIS techniques, which preserve bone, paraspinal musculature, and posterior midline stabilizers, are thought to reduce the risk of iatrogenic instability and may obviate the need for fusion. However, few comparative studies of MIS techniques for low-grade lumbar degenerative spondylolisthesis currently exist., Materials and Methods: Consecutive patients with low-grade (Meyerding grade I or II) lumbar degenerative spondylolisthesis treated with single-level MIS-ULBD or MIS-TLIF were identified retrospectively from a prospectively collected spine surgery registry from April 2017 to November 2021. Perioperative outcomes, radiographic data, and PROMs were assessed., Results: A total of 188 patients underwent either MIS-ULBD or MIS-TLIF (79 MIS-ULBD and 109 MIS-TLIF). Patients who underwent MIS-ULBD tended to be older, had higher Charlson Comorbidity Index, lower mean percentage back pain, higher percentage of L4/L5 pathology, shorter operative time, lower estimated blood loss, and lower postoperative pain ( P <0.05). In both groups, there were statistically significant improvements at one year for five of the six PROMs studied: Oswestry Disability Index (ODI), visual analog scale (VAS)-back pain, VAS-leg pain, Short Form 12 Physical Component Score (SF12-PCS), and Patient-Reported Outcomes Measurement Information System (PROMIS) ( P <0.05). On multivariate analysis controlling for confounders, there were no associations between procedure type and achieving minimal clinically important difference at one year in any of the PROMs studied., Conclusions: The current study suggests that both MIS-ULBD and MIS-TLIF result in significant improvements in pain and physical function for patients with low-grade lumbar degenerative spondylolisthesis., Level of Evidences: 3., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Degenerative spondylolisthesis (DS) is one of the most common pathologies spine surgeons treat. While a number of potential factors have been identified, there is no current consensus on which variables most impact the decision to fuse vs. decompress alone in this population., Purpose: The purpose of this study was to describe current DS treatment practices and identify both the radiographic and clinical factors leading to the decision to fuse segments for one level DS., Study Design/setting: Descriptive cross-sectional survey., Patient Sample: Surveys were administered to members of Lumbar Spine Research Society and Society of Minimally Invasive Spine Surgery., Outcome Measures: Surgeon demographics and treatment practices were reported. Radiographic and clinical parameters were ranked by each surgeon with regards to their importance., Methods: The primary analysis was limited to completed surveys. Baseline characteristics were summarized. Clinical and radiographic parameters were ranked and compared. Ranking of each clinical and radiographic parameters was reported using best and worst rank, mean rank position, and percentiles. The most important, top 3 most important, and top 5 most important parameters were ordered given each parameter's ranking frequency., Results: 381 surveys were returned completed. With regards to fusion vs. decompression, 19.9% fuse all cases, 39.1% fuse > 75%, 17.8% fuse 50%-75%, and 23.2% fuse <25%. The most common decompressive technique was a partial laminotomy (51.4%), followed by full laminectomy (28.9%). 82.2% of respondents instrument all fusion cases. Instability (93.2%), spondylolisthesis grade (59.8%), and laterolisthesis (37.3%) were the most common radiographic factors impacting the decision to fuse. With regards to the clinical factors leading to fusion, mechanical low back pain (83.2%), activity level (58.3%), and neurogenic claudication (42.8%) were the top 3 clinical parameters., Conclusions: There is little consensus on the treatment of DS, with society members showing substantial variation in treatment patterns with the majority utilizing fusion for treatment. The most common radiographic parameters impacting treatment are instability, spondylolisthesis grade, and laterolisthesis while mechanical low back pain, activity level, and neurogenic claudication are the most common clinical parameters., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Study Design: A Retrospective cohort study., Objective: To (1) assess whether diagnoses and surgical plans established during a new patient telemedicine visit changed following an in-person evaluation and (2) determine any differences in perioperative outcomes between patients who only had a telemedicine visit before surgery versus those who had a telemedicine visit followed by an in-person evaluation before surgery., Summary of Background Data: Data on capability of telemedicine to deliver high-quality preoperative assessment without a traditional in-person interaction and physical examination is lacking., Materials and Methods: Records of patients who had a new patient telemedicine visit and indicated for surgery with documented specific diagnosis as well as surgical plans from a spine department at an urban tertiary center from April 2020 to April 2021 were reviewed. For a subset of patients that had a follow-up in-person evaluation before surgery, these diagnoses and plans were compared. Perioperative outcomes were compared between patients who only had a telemedicine visit before surgery versus those who had a telemedicine visit followed by an in-person evaluation before surgery., Results: A total of 166 patients were included. Of these, 101 patients (61%) only had a new patient telemedicine visit before surgery while 65 (39%) had a telemedicine visit followed by an in-person evaluation. There were no differences in the rate of case cancellations before surgery and patient-reported outcome measures between these two groups ( P >0.05). Of 65 patients who had both a telemedicine followed by an in-person visit, the diagnosis was unchanged for 61 patients (94%) and the surgical plan did not change for 52 patients (80%). The main reason for surgical plan change was due to updated findings on new imaging, 10 patients, (77%)., Conclusions: The current study suggests that telemedicine evaluations can provide an effective means of preoperative assessment for spine patients., Level of Evidence: Level 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: This study introduces a novel surface-topographic scanning system capable of automatically generating a suite of objective measurements to characterize torso shape., Research Question: what is the reliability of the proposed system for measurement of trunk alignment parameters in patients with adolescent idiopathic scoliosis (AIS) and controls?, Methods: Forty-six adolescents (26 with AIS and 20 controls) were recruited for a prospective reliability study. A series of angular, volumetric, and area measures were computed from topographic scans in each of three clinically relevant poses using a fully automated processing pipeline. Intraclass correlation coefficients (ICC(2,1)) were computed within (intra-) and between (inter-) raters. Measurements were also performed on a torso phantom., Results: Topographic measurements computed on a phantom were highly accurate (mean RMS error 1.7%) compared with CT. For human subjects, intra- and inter-rater reliability were both high (average ICC > 0.90) with intrinsic (pose-independent) measurements having near-perfect reliability (average ICC > 0.98)., Conclusion: The proposed system is a suitable tool for topographic analysis of AIS; topographic measurements offer an objective description of torso shape that may complement other imaging modalities. Further research is needed to compare topographic findings with gold standard imaging of spinal alignment, e.g., standing radiography., Conclusion: clinical parameters can be reliably measured in a fully automated system, paving the way for objective analysis of symmetry, body shape pre/post-surgery, and tracking of pathology without ionizing radiation., (© 2022. The Author(s).)

Objective: The objective of this study was to initially validate a recent morphological classification of cervical spine deformity pathology., Methods: The records of 10 patients for each of the 3 classification subgroups (flat neck, focal deformity, and cervicothoracic), as well as for 8 patients with coronal deformity only, were extracted from a prospective multicenter database of patients with cervical deformity (CD). A panel of 15 physicians of various training and professional levels (i.e., residents, fellows, and surgeons) categorized each patient into one of the 4 groups. The Fleiss kappa coefficient was utilized to evaluate intra- and interrater reliability. Accuracy, defined as properly selecting the main driver of deformity, was reported overall, by morphotype, and by reviewer experience., Results: The overall classification demonstrated a moderate to substantial agreement (round 1: interrater Fleiss kappa = 0.563, 95% CI 0.559-0.568; round 2: interrater Fleiss kappa = 0.612, 95% CI 0.606-0.619). Stratification by level of training demonstrated similar mean interrater coefficients (residents 0.547, fellows 0.600, surgeons 0.524). The mean intrarater score was 0.686 (range 0.531-0.823). A substantial agreement between rounds 1 and 2 was demonstrated in 81.8% of the raters, with a kappa score > 0.61. Stratification by level of training demonstrated similar mean intrarater coefficients (residents 0.715, fellows 0.640, surgeons 0.682). Of 570 possible questions, reviewers provided 419 correct answers (73.5%). When considering the true answer as being selected by at least one of the two main drivers of deformity, the overall accuracy increased to 86.0%., Conclusions: This initial validation of a CD morphological classification system reiterates the importance of dynamic plain radiographs for the evaluation of patients with CD. The overall reliability of this CD morphological classification has been demonstrated. The overall accuracy of the classification system was not impacted by rater experience, demonstrating its simplicity.

Study Design: Systematic review., Objective: Indirect decompression via lateral lumbar interbody fusion (LLIF) can ameliorate central and foraminal lumbar stenosis. In severe central stenosis, additional posterior direct decompression is utilized. The aim of this review is to synthesize existing literature on these 2 techniques and identify significant differences in outcomes between isolated indirect decompression via LLIF and combined indirect decompression supplemented with direct posterior decompression., Methods: A database search algorithm was utilized to query MEDLINE, COCHRANE, and EMBASE to identify literature reporting adult decompression study groups that involved an oblique or lateral fusion approach through September 2020. Improvement in outcomes measures and complication rates were pooled and tested for significance., Results: A total of 110 publications were assessed with 15 studies meeting inclusion criteria, including 557 patients and 1008 levels. Mean age was 63.1 years with BMI of 27.5 kg/m 2 . For the combined indirect and direct decompression cohort, lumbar lordosis (LL) increased 133.9%, from 22.8 o to 48.7 o , while the indirect decompression cohort LL increased 8.9%, from 41.9 o to 45.5 o . Difference in LL improvement between cohorts was insignificant ( P > .05). Oswestry Disability Index (ODI) decreased from 36.5 to 19.4 in the combined indirect and direct decompression cohort, and from 44.4 to 23.1 in the indirect decompression cohort. ODI reduction was insignificant ( P = .053)., Conclusions: Prior studies of both indirect decompression as well as combined indirect and direct decompression of lumbar spine stenosis are limited by small samples, heterogeneous populations, and lack of direct comparisons. Both procedures result in improved function and pain postoperatively with direct decompression restoring more lordosis in patients with worse preoperative alignment.

Purpose: To determine the association of preoperative opioid prescriptions with reoperations and postoperative opioid prescriptions after adult spina deformity (ASD) surgery. With the current opioid crisis, patients undergoing surgery for ASD are at particular risk for opioid-related complications due to significant preoperative disability and surgical morbidity. No previous studies consider preoperative opioids in this population., Methods: A retrospective cohort study of patients undergoing posterior spinal fusion (7 or more levels) for ASD was performed. All patients had at least 3 years of postoperative follow-up 3 years postoperatively. Prescriptions for 4 different opioid medications (hydromorphone, oxycodone, hydrocodone, and tramadol) were identified within 3 months preoperatively and up to 3 years postoperatively. Multivariate regression was utilized to determine the association of preoperative use with reoperations and with postoperative opioid use, controlling for both patient and surgery-related confounding factors., Results: A total of 743 patients were identified and 59.6% (443) had opioid prescriptions within 3 months preoperatively. Postoperative opioid prescriptions were identified in 66.9% of patients at 12 months postoperatively, and in 54.8% at 36 months postoperatively. The 3-year reoperation rate was 11.0% in patients without preoperative prescriptions, 16.0% in patients with preoperative any opioid prescriptions (P = 0.07), and 34.8% in patients with preoperative hydromorphone prescriptions (P < 0.01). In multivariate analysis, preoperative opioid prescriptions were associated with increased reoperations (odds ratio [OR]: 1.62, P = 0.04), and chronic postoperative opioid use (OR: 4.40, P < 0.01). Preoperative hydromorphone prescriptions had the strongest association with both reoperations (OR: 4.96; P < 0.01) and chronic use (OR: 5.19: P = 0.03)., Conclusion: In the ASD population, preoperative opioids are associated with both reoperations and chronic opioid use, with hydromorphone having the strongest association. Further investigation of the benefits of preoperative weaning programs is warranted., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are cost-effective procedures that decrease pain and improve health-related quality of life for patients with advanced symptomatic arthritis, including rheumatoid arthritis (RA). Patients with RA have a longer length of stay (LOS) after THA or TKA than patients with osteoarthritis, yet the factors contributing to LOS have not been investigated. Purpose : We sought to identify the factors contributing to LOS for patients with RA undergoing THA and TKA at a single tertiary care orthopedic specialty hospital. Methods : We retrospectively reviewed data from a prospectively collected cohort of 252 RA patients undergoing either THA or TKA. Demographics, RA characteristics, medications, serologies, and disease activity were collected preoperatively. Linear regression was performed to explore the relationship between LOS (log-transformed) and possible predictors. A multivariate model was constructed through backward selection using significant predictors from a univariate analysis. Results : Of the 252 patients with RA, 83% were women; they had a median disease duration of 14 years and moderate disease activity at the time of arthroplasty. We had LOS data on 240 (95%) of the cases. The mean LOS was 3.4 ± 1.5 days. The multivariate analysis revealed a longer LOS for RA patients who underwent TKA versus THA, were women versus men, required a blood transfusion, and took preoperative opioids. Conclusion : Our retrospective study found that increased postoperative LOS in RA patients undergoing THA or TKA was associated with factors both non-modifiable (type of surgery, sex) and modifiable (postoperative blood transfusion, preoperative opioid use). These findings suggest that preoperative optimization of the patient with RA might focus on improving anemia and reducing opioid use in efforts to shorten LOS. More rigorous study is warranted., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Kyle W. Morse, MD, Nicole K. Heinz, PA-C, Jeremy M. Abolade, BS, Joshua Wright-Chisem, MD, Meng Zhang, PhD, Serene Mirza, BS, Linda Alice Russell, MD, and Diyu Pearce-Fisher, BS have declared no potential conflicts of interest. Dana E. Orange, MD, MS, reports relationships with Astra Zeneca/MedImmune and Pfizer. Mark P. Figgie, MD, reports relationships with Wishbone, Lima, Insight Medical, HSZ, and Mekanika. Peter K. Sculco, MD, reports relationships with EOS Imaging, Intellijoint Surgical, DePuy Synthes, Lima Corporate, and Zimmer Biomet. Susan M. Goodman, MD, reports relationships with Novartis and Horizon Pharmaceuticals., (© The Author(s) 2022.)

Purpose: The distinction between the dorsal intercarpal (DIC) and dorsal scaphotriquetral (DST) ligaments is imprecise and unclear in the literature. The purpose of our cadaveric study was to define the origins, insertions, and anatomic relationships of the dorsal wrist ligaments and relate these anatomic findings to magnetic resonance imaging (MRI) scans and histology., Methods: The study included 17 unmatched fresh-frozen cadaveric specimens (7 male and 10 female), with a mean age of 67.1 years (range, 48-86 years). Wrists with arthritis or carpal malalignment were excluded. Ligaments were dissected and insertion sites were recorded in the radioulnar (width) and proximodistal (length) dimensions, centered at the midpoints of the insertion. Three cadaveric specimens underwent a histologic analysis to demonstrate ligament composition and insertion sites. Three additional cadavers underwent MRI, from which 3-dimensional models were built to model ligament topography., Results: The conjoined triquetral insertion of the DIC, DST, and dorsal radiocarpal (DRC) measured 88.5 ± 6.4 mm 2 . In each specimen, there were 2 distinct deep and superficial components of intercarpal fibers. The deep component inserted on the lunate with an area of 59.0 ± 5.0 mm 2 . The deep and superficial components diverged as they coursed radially. The superficial component proceeded to the scaphoid ridge, trapezium, and trapezoid, whereas the deep component inserted on the proximal row. The deep fibers blended distally from their lunate insertion with the DST, forming a robust, 2.9 ± 0.8-mm wide extension over the dorsal capitate. The DRC inserted on the lunate, proximal to the DIC and DST insertions, with an area of 23.9 ± 5.4 mm 2 ., Conclusions: The dorsal ligament complex forms a firm link across the proximal carpal row and the DST provides extension of the proximal row over the capitate., Clinical Relevance: This information can guide surgeons while performing a dorsal approach to the wrist and repairing traumatic ligament disruption., (Copyright © 2022 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background Context: Patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) frequently present with lower extremity neurologic symptoms with or without associated lower back pain. While symptomatic improvement of leg and back pain has been reported, the resolution of back pain when it is a predominant presenting symptom remains underreported following MI-TLIF., Purpose: The purpose of this study was to compare clinical outcomes at 1 year of patients undergoing MI-TLIF with lower extremity neurologic symptoms with and without a significant component of back pain., Study Design: A retrospective review of prospectively collected data from a single surgeon surgical database from 2017 to 2019 was performed., Patient Sample: Fifty one patients undergoing MI-TLIF., Outcome Measures: Self-reported measures included the Oswestry Disability Index (ODI), Visual analog scale back pain (VAS-back), and VAS leg pain (VAS-leg)., Methods: Patients were divided into two groups: Leg Pain Predominant (patients reported greater than 50% leg pain upon presentation) and Back Pain Predominant (patients reported 50% or greater back pain). Multivariate analysis was performed to determine differences between groups based upon any significantly baseline characteristics., Results: Preoperative demographic and radiographic outcomes were similar between the two groups. Both groups demonstrated significant improvement in ODI, VAS-Back and VAS-leg at 1-year postoperatively. On multivariate analysis, there were differences in ODI at 1-year, 1-year back pain, and 1-year leg pain between groups with those who initially presented with leg pain having a lower ODI, VAS Back, and VAS leg. Patients who presented with predominantly leg pain were more likely to meet minimal clinically important difference (MCID) criteria for ODI and VAS-back compared to those with predominantly back pain., Conclusion: Following MI-TLIF, patients with lower extremity neurologic symptoms with and without a significant component of back pain have improvements in back pain, leg pain, and ODI regardless of their primary presenting pain complaint; however, patients who presented with predominantly leg pain were more likely to meet MCID criteria for improvement in their back pain and ODI score., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: To compare the kinematic effects of the dorsal fiber-splitting approach for scapholunate ligament repair to a dorsal "window" approach that spares all ligaments., Methods: We randomized 24 fresh-frozen paired cadaveric forearms to either the dorsal fiber-splitting capsulotomy approach (FSC) or the dorsal window approach (window) following scapholunate interosseous ligament (SLIL) division. Loaded fluoroscopic radiographs were obtained after each of the 4 testing conditions following cyclic loading (200 cycles; 71 N): (1) intact SLIL, (2) SLIL-division, (3) surgical approach, and (4) closure. FSC specimens were randomly allocated to 2 subgroups for closure with either a suture anchor (n = 6) or a simple running suture closure (n = 6). Radiographic parameter measurements included the scapholunate gap, radiolunate angle, scapholunate angle, and dorsal scaphoid translation., Results: Following the FSC, there were significant alterations in all radiographic parameters when compared with the intact and SLIL-division conditions. The window approach did not result in significant changes in any radiographic parameter. When compared to the window approach, all radiographic parameters of the FSC approach were significantly altered. Following closure with suture anchors in the FSC group, radiographic parameters improved, whereas with standard closure they failed to do so. Despite anchor closure, dorsal scaphoid translation, radiolunate angle, and scapholunate angle all remained elevated compared with scapholunate-divided wrists., Conclusions: The FSC produced significant changes in carpal posture under load, including scapholunate diastasis, dorsal intercalated segment instability, and dorsal scaphoid translation in SLIL-deficient wrists. The window approach preserved the critical dorsal ligament stabilizers and did not produce changes in carpal posture., Clinical Relevance: The FSC may create iatrogenic changes in carpal posture that cannot be fully corrected with standard or anchor closure. The window approach does not alter carpal posture and should be considered when performing surgical procedures on the scaphoid or lunate., (Copyright © 2021 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Introduction: Pediatric spinal deformity involves a complex 3-dimensional (3D) deformity that increases the risk of pedicle screw placement due to the close proximity of neurovascular structures. To increase screw accuracy, improve patient safety, and minimize surgical complications, the placement of pedicle screws is evolving from freehand techniques to computer-assisted navigation and to the introduction of robotic-assisted placement. Purpose : The aim of this review was to review the current literature on the use of robotic navigation in pediatric spinal deformity surgery to provide both an error analysis of these techniques and to provide recommendations to ensure its safe application. Methods : A narrative review was conducted in April 2021 using the MEDLINE (PubMed) database. Studies were included if they were peer-reviewed retrospective or prospective studies, included pediatric patients, included a primary diagnosis of pediatric spine deformity, utilized robotic-assisted spinal surgery techniques, and reported thoracic or lumbar pedicle screw breach rates or pedicle screw malpositioning. Results : In the few studies published on the use of robotic techniques in pediatric spinal deformity surgery, several found associations between the technology and increased rates of screw placement accuracy, reduced rates of breach, and minimal complications. All were retrospective studies. Conclusions : Current literature is of a low level of evidence; nonetheless, the findings suggest the accuracy and safety of robotic-assisted spinal surgery in pediatric pedicle screw placement. The introduction of robotics may drive further advances in less invasive pediatric spinal deformity surgery. Further study is warranted., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Roger F. Widmann, MD, reports a relationship with Medtronic. The other authors declared no potential conflicts of interest., (© The Author(s) 2021.)

Background: Surgical navigation improves pedicle screw insertion accuracy and reliability. Robotic-assisted spinal surgery and screw placement has not been fully assessed in pediatric patients with spine deformity undergoing posterior spinal fusion. The purpose of this study was to describe the learning curve for robotically assisted pedicle screw placement in pediatric patients., Methods: A retrospective review on a consecutive series of the first 19 pediatric patients who underwent posterior spinal fusion by a single surgeon using robotic navigation was performed. Demographics, curve parameters, pedicle diameter, vertebral rotation, and additional outcome measures were recorded. Screw position was assessed with calibrated intraoperative 3-dimensional fluoroscopic images. All complications of planned and placed robotically placed screws were recorded., Results: A total of 194 left-sided screws were planned as robot-assisted. One hundred sixty-eight of the robotically planned screws (86.6%) were placed with robot assistance; 29 robotically planned screws (15.0%) were abandoned or converted to freehand. The mean time per robotically placed screw was 3.6±2.4 minutes. Fifteen breaches (8.9%) and 1 anterior perforation occurred with 2 critical (>2 to 4 mm) breaches, 1 was associated with a durotomy, and both occurred in the first case. There were no intraoperative/postoperative neuromonitoring changes and no sequela from the durotomy. Six breaches occurred in the first case. The odds ratio of obtaining a breach in screws with a matched trajectory was 0.275 (95% confidence interval: 0.089-0.848)., Conclusions: Screw time and accuracy improved and the number of breaches decreased after 10 cases. This series had 2 critical breaches (between 2 and 4 mm) on the first case. Overall, excluding the 2 critical breaches, 98.8% of robotically executed screws were placed without a critical breach, which is comparable to previous pediatric deformity studies. Caution should be exercised during the initial training period to avoid complications as experience and training lead to an improved understanding of surgical planning, skive, and soft-tissue pressure on the end-effector all of which can impact accuracy of robotically assisted pedicle screw placement., Level of Evidence: Case Series, IV., Competing Interests: D.R.L. and R.F.W. are consultants for Medtronic and they were not paid for their involvement in this study, which may result in a potential conflict of interest bias. However, the retrospective nature of the study resulted in independent researchers conducting independent data analysis and manuscript writing limits this potential for bias. One author has a consulting fee range of $1.00 to $ 10,000 (B) and the second has not received any compensation for research, education or consulting. The remaining authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: K-wireless robotic pedicle screw instrumentation with navigation is a new technology with large potential. Barriers to adoption are added registration time with robotic-navigated system and reliable screw positioning. Understanding the learning curve and limitations is crucial for successful implementation. The purpose of this study was to describe a learning curve of k-wireless robotic assisted pedicle screw placement with navigation and compare to conventional techniques., Methods: A retrospective review of prospectively collected data of 65 consecutive adult patients underwent robotic-navigated posterior spinal fusion by a single spine surgeon. Registration, screw placement, and positioning times were recorded. All patients underwent intra-operative 3D fluoroscopy and screw trajectory was compared to pre-operative CT., Results: A total of 364 instrumented pedicles were planned robotically, 311 (85.4%) were placed robotically; 17 screws (4.7%) converted to k-wire, 21 (5.8%) converted to freehand, and 15 (4.1%) planned freehand. Of the 311 robotically placed pedicle screws, three dimensional fluoroscopic imaging showed 291 (93.5%) to be GRS Grade A in the axial plane (fully contained within the pedicle) and 281 (90.4%) were GRS Grade A in the sagittal plane. All breached screw deviations from plan were identified on 3D fluoroscopy during surgery and repositioned and confirmed by additional 3d fluoroscopy scan. Reasons for conversion included morphology of starting point (n=18), soft tissue pressure (n=9), hypoplastic pedicles (n=6), obstructive reference pin placement (n=2), and robotic arm issues (n=1). Seventeen (5.5%) critical breaches (≥2-4 mm) were recorded in 11 patients, 9 (2.9%) critical breaches were due to soft tissue pressure causing skive. Two patients experienced 6 (1.9%) critical breaches from hypoplastic pedicles, and 3 (0.9%) unplanned lateral breaches were found in another patient. One patient (0.3%) experienced skive due to morphology and spinal instability from isthmic spondylolisthesis. Imaging showed 143 screws placed medially to plan (1.2±0.9 mm), 170 lateral (1.2±1.1 mm), 193 screws caudal (1.0±0.6 mm) and 117 cranial (0.6±0.5 mm). No adverse clinical sequelae occurred from implantation of any screw., Conclusions: The learning curve showed improvement in screw times for the first several cases. Understanding the learning curve and situations where the robotic technique may be suboptimal can help guide the surgeon safe and effectively for adoption, as well as further refine these technologies., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jss-20-687). DRL reports research support from Medtronic, during the conduct of the study; royalties from K2M- Stryker, royalties from NuVasive, ownership interest from Woven Orthopedic Technologies, ownership interest from Vestia Ventures MiRus Investment LLC, investment interest from ISPH II, LLC, outside the submitted work. RFW reports personal fees from Medtronic, outside the submitted work, and fee for Service Consultant to OrthoPediatric Company Spine Division. RFM is on the editorial board Spine Deformity Journal, editorial board of The Journal of Children’s Orthopaedics, and a consultant reviewer for the Journal of Pediatric Orthopaedics. The other authors have no conflicts of interests to declare., (2021 Journal of Spine Surgery. All rights reserved.)

Background: Femoroacetabular impingement and degenerative hip osteoarthritis (OA) affect athletes across a wide variety of sports. Hip resurfacing arthroplasty (HRA) has emerged as a surgical treatment for active individuals with end-stage hip OA to provide pain relief and allow return to high-impact activities. Return to professional sports after HRA has not been well characterized., Purpose/hypothesis: The aim of this study was to report on a series of elite athletes in a variety of sports who underwent HRA. We hypothesized that professional and elite-level athletes would be able to return to sports after HRA for end-stage hip OA., Study Design: Case series; Level of evidence, 4., Methods: A retrospective case series was conducted on professional athletes who underwent HRA at a single institution between 2007 and 2017. All surgeries were performed by a single surgeon using the posterolateral approach. Athletes' return to play and sport-specific performance statistics were obtained using self-reported and publicly available data sources. Athletes were matched to an age- and performance-based cohort to determine changes in performance-based metrics., Results: Eight professional athletes were identified, including 2 baseball pitchers, 1 ice hockey defenseman, 1 foil fencer, 1 men's doubles tennis player, 1 basketball player, 1 ultramarathoner, and 1 Ironman triathlete. All 8 patients returned to sports; 6 of 8 (75%) patients were able to return for at least 1 full season at a professional level after surgery. There were no significant differences between performance statistics for athletes who returned to play and their preoperative performance measures for the years leading up to surgery or the age- and performance-matched cohort., Conclusion: HRA remains a surgical alternative for end-stage hip OA in young, high-impact, active patients. While the primary goals of surgery are pain control and quality of life improvement, it is possible to return to elite-level sporting activity after HRA., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: E.P.S. has received educational support from Arthrex and Elite Orthopedics; has received research support from Smith & Nephew and United Orthopedic; has received consulting fees from Orthalign, Smith & Nephew, and United Orthopedic; has received nonconsulting fees from Smith & Nephew; has received royalties from Kyocera, Orthalign, and United Orthopedic; has received hospitality payments from B. Braun; has stock/stock options in Insight Medical Systems; and is the founder of Engage Uni. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Study Design: Retrospective review of a prospective multicenter cervical deformity database., Objective: To examine the differences in sagittal alignment correction between three positioning methods in cervical spinal deformity surgery (CD)., Summary of Background Data: Surgical correction for CD is technically demanding and various techniques are utilized to achieve sagittal alignment objectives. The effect of different patient positioning techniques on sagittal alignment correction following CD remains unknown., Methods: Patients with sagittal deformity who underwent a posterior approach (with and without anterior approach) with an upper instrumented vertebra of C6 or above. Patients with Grade 5, 6, or 7 osteotomies were excluded. Positioning groups were Mayfield skull clamp, bivector traction, and halo ring. Preoperative lower surgical sagittal curve (C2-C7), C2-C7 sagittal vertical axis (cSVA), cervical scoliosis, T1 slope minus cervical lordosis (TS-CL), T1 slope (T1S), chin-brow vertebral angle (CBVA), C2-T3 curve, and C2-T3 SVA was assessed and compared with postoperative radiographs. Segmental changes were analyzed using the Fergusson method., Results: Eighty patients (58% female) with a mean age of 60.6 ± 10.5 years (range, 31-83) were included. The mean postoperative C2-C7 lordosis was 7.8° ± 14 and C2-C7 SVA was 34.1 mm ± 15. There were overall significant changes in cervical alignment across the entire cohort, with improvements in T1 slope (P < 0.001), C2-C7 (P < 0.001), TS-CL (P < 0.001), and cSVA (P = 0.006). There were no differences postoperatively of any radiographic parameter between positioning groups (P > 0.05). The majority of segmental lordotic correction was achieved at C4-5-6 (mean 6.9° ± 11). Additionally, patients who had bivector traction applied had had significantly more segmental correction at C7-T1-T2 compared with Mayfield and halo traction (4.2° vs. 0.3° vs. -1.7° respectively, P < 0.027)., Conclusion: Postoperative cervical sagittal correction or alignment was not affected by patient position. The majority of segmental correction occurred at C4-5-6 across all positioning methods, while bivector traction had the largest corrective ability at the cervicothoracic junction.Level of Evidence: 4., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Competing Interests: Conflict of InterestMathias P. Bostrom, MD, reports grants and personal fees from Smith & Nephew, outside the submitted work. Han Jo Kim, MD, reports personal fees and royalties from Zimmer Biomet and K2M Strkyer, personal fees from Alphatec, and research support from the National Institutes of Health, International Spine Study Group, and Cervical Spine Research Society, outside the submitted work. Michael Cross, MD, reports personal fees from 3M KCI, DePuy Synthes, Exactech, Flexion Therapeutics, Imagen Technologies, Insight Medical, Intellijoint Surgical, Parvizi Surgical Innovation, and Smith & Nephew, as well as board membership at Bone and Joint Journal 360, Journal of Orthopaedics and Technology, and Techniques in Orthopaedics, outside the submitted work. Anil Ranawat, MD, reports personal fees from Enhatch, Conformis, Strathspey Crown, Styker, Arthrex, Smith & Nephew, Ceramtec, Anika, Bodycad, Convatec, and Depuy Synthes, outside the submitted work. Benedict U. Nwachukwu, MD, MBA, reports educational support from Smith & Nephew and Stryker, outside the submitted work. Duretti T. Fufa, MD, reports personal fees from Medartis and Integra LifeSciences, outside the submitted work. All other authors declare that they have no conflicts of interest.

Background: Healthcare resources have been greatly limited by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic halting non-essential surgical cases without clear service expansion protocols., Questions/purposes: We sought to compare the peri-operative outcomes of patients undergoing spine surgery during the SARS-CoV-2 pandemic to a matched cohort prior to the pandemic., Methods: We identified a consecutive sample of 127 adult patients undergoing spine surgery between March 9, 2020, and April 10, 2020, corresponding with the state of emergency declared in New York and the latest possible time for 1-month surgical follow-up. The study group was matched one-to-one based on age, gender, and body mass index with eligible control patients who underwent similar spine procedures prior to the SARS-CoV-2 outbreak. Surgeries performed for infectious or oncologic indications were excluded. Intra- and post-operative complication rates, re-operations, hospital length of stay, re-admissions, post-operative visit format, development of post-operative fever and/or respiratory symptoms, and SAR-CoV2 testing., Results: A total of 254 patients (127 SARS-CoV-2 pandemic, 127 matched controls) were included. One hundred fifty-eight were male (62%), and 96 were female (38%). The mean age in the pandemic group was 59.8 ± 13.4 years; that of the matched controls was 60.3 ± 12.3. All patients underwent general anesthesia and did not require re-intubation. There were no significant differences in 1-month post-operative complication rates (16.5% pandemic vs. 12.6% control). There was one death in the pandemic group. No patients tested positive for the virus., Conclusion: This study represents the first report of post-operative outcomes in a large group of spine surgical patients in an area heavily affected by the SARS-CoV-2 pandemic., Competing Interests: Conflict of InterestPhilip K. Louie, MD; Lauren A. Barber, MD; Kyle W. Morse, MD; Marie Syku, BS; Virginie Lafage, PhD; Russel C. Huang, MD; and Alberto V. Carli, MD, declare that they have no conflicts of interest. Sheeraz A. Qureshi, MD, MBA, reports personal fees from Stryker K2M, Globus Medical, Inc., Paradigm Spine, RTI Surgical Inc., AMOpportunities, Healthgrades, and Simplify Medical, Inc.; investment or ownership interest in Avaz Surgical and Vital 5; committee or board membership in the International Society for the Advancement of Spine Surgery, Global Spine Journal, The American Orthopaedic Association, North American Spine Society, LifeLink.com Inc., Association of Bone and Joint Surgeons, Society of Lateral Access, Spine (Journal), The Spine Journal, Society of Minimally Invasive Spine Surgery, Minimally Invasive Spine Study Group, Spinal Simplicity, LLC, Contemporary Spine Surgery, Annals of Translational Medicine, Journal of American Academy of Orthopaedic Surgeons, and Cervical Spine Research Society, outside the submitted work., (© Hospital for Special Surgery 2020.)

Background: Patients with rheumatoid arthritis (RA) receive transfusions more often than patients with osteoarthritis following lower extremity total joint arthroplasty (TJA), but mitigating factors are not described. Tranexamic acid (TXA) is widely used to reduce blood loss in patients undergoing TJA, but its effect on transfusion rates in patients with RA has not been studied., Methods: We retrospectively reviewed data from a prospectively collected cohort of patients with RA undergoing TJA. Disease activity measured by Clinical Disease Activity Index, patient-reported outcome measures, and serologies was obtained. Baseline characteristics were summarized and compared. Transfusion requirements and TXA usage were obtained from chart review. Logistic regression was used to determine factors associated with transfusion in RA patients undergoing TJA., Results: The cohort included 252 patients, mostly women with longstanding RA and end-stage arthritis requiring TJA. In multivariate analysis, 1 g/dL decrease in baseline hemoglobin (odds ratio [OR] = 0.394, 95% confidence interval [CI] [0.232, 0.669], P = .001), 1-minute increase in surgical duration (OR = 1.022, 95% CI [1.008, 1.037], P = .003), and 1-point increase in Clinical Disease Activity Index (OR = 1.079, 95% CI [1.001, 1.162]) were associated with increased risk of transfusion. TXA use was not associated with decreased risk of postoperative transfusion., Conclusions: Preoperative health optimization should include assessment and treatment of anemia in RA patients before TJA, as preoperative hemoglobin level is the main risk factor for postoperative transfusion. Increased disease activity and increased surgical time were independent risk factors for postoperative transfusion but are less modifiable. While TXA did not decrease transfusion risk in this population, a prospective trial is needed to confirm this., Level of Evidence: IV., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Most minimally displaced scaphoid fractures and all displaced scaphoid fractures in elite athletes are treated with early fixation to maximally expedite the return to full function. Computed tomographic (CT) scans are recommended in all scaphoid fractures to facilitate a complete understanding of fracture anatomy and to allow for optimal screw placement. Screw placement is important to maximize healing capacity of the fracture and allow for return to sport. Postoperative CT scans can be helpful to evaluate the extent of healing and may allow patients to return to play sooner., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose of Review: To summarize the current anatomy, biomechanics, presentation, treatment, and outcomes of injuries to the biceps and superior labral complex in overhead athletes., Recent Findings: The biceps and superior labral complex is composed of anatomically distinct zones. The inability to accurately diagnose biceps lesions contributes to continued morbidity especially as arthroscopy and advanced imaging fail to fully evaluate the entire course of the biceps tendon. Superior labrum anterior and posterior (SLAP) repair, long head of biceps tenodesis, and tenotomy are the most common operative techniques for surgical treatment of biceps-labral complex (BLC) pathology. Labral repair in overhead athletes has resulted in mixed outcomes for athletes and is best indicated for patients under age 40 years old. Injuries to the BLC are potentially challenging injuries to diagnose and treat, particularly in the overhead athlete. SLAP repair remains the treatment of choice for high-level overhead athletes and patients younger than 40 years of age, while biceps tenodesis and tenotomy are preferred for older patients.

Background  Ideal internal fixation of the scaphoid relies on adequate bone stock for screw purchase; so, knowledge of regional bone density of the scaphoid is crucial. Questions/Purpose  The purpose of this study was to evaluate regional variations in scaphoid bone density. Materials and Methods  Three-dimensional CT models of fractured scaphoids were created and sectioned into proximal/distal segments and then into quadrants (volar/dorsal/radial/ulnar). Concentric shells in the proximal and distal pole were constructed in 2-mm increments moving from exterior to interior. Bone density was measured in Hounsfield units (HU). Results  Bone density of the distal scaphoid (453.2 ± 70.8 HU) was less than the proximal scaphoid (619.8 ± 124.2 HU). There was no difference in bone density between the four quadrants in either pole. In both the poles, the first subchondral shell was the densest. In both the proximal and distal poles, bone density decreased significantly in all three deeper shells. Conclusion  The proximal scaphoid had a greater density than the distal scaphoid. Within the poles, there was no difference in bone density between the quadrants. The subchondral 2-mm shell had the greatest density. Bone density dropped off significantly between the first and second shell in both the proximal and distal scaphoids. Clinical Relevance  In scaphoid fracture ORIF, optimal screw placement engages the subchondral 2-mm shell, especially in the distal pole, which has an overall lower bone density, and the second shell has only two-third the density of the first shell.

Introduction: Modern metal-on-metal hip resurfacing arthroplasty has led to decreased revision rates and high implant survival rates as compared to prior generations of resurfacing. Many of the series that report on resurfacing outcomes focus upon patients treated with a diagnosis of osteoarthritis. Patients with inflammatory arthritis such as rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are also treated in these series, however, their outcomes following resurfacing are underreported. The aim of this study was to determine complications that may occur following hip resurfacing in patients with inflammatory arthritis. A secondary aim was to determine functional outcomes following resurfacing., Methods: A search was performed in MEDLINE (PubMed/OVID), Cochrane Library, and Google Scholar. 5 studies met eligibility criteria. This review includes 196 hips; 120 had a diagnosis of AS or seronegative spondyloarthropathy and 76 had a diagnosis of RA or juvenile RA. 8 revisions were reported at a mean time of 64.2 (8.67-275.58) weeks., Results: Femoral neck fracture was the most common indication for revision, occurring in 3.06% of all hips at 34.5 weeks (16.0-52.0). 2 infections, 2 reports of acetabular radiolucency, and no dislocations were reported. The University of California at Los Angeles score, Harris Hip Score, and Range of Motion were the most common functional outcomes measured, which increased in the majority of studies following resurfacing., Conclusions: Femoral neck fracture was the most common reason for revision in patients with inflammatory arthritis following resurfacing and there were no dislocations reported. Following resurfacing, these patients have improved functional outcomes.

Purpose: Several surgical stabilization techniques have been described to address pathological subluxation of the extensor carpi ulnaris (ECU) tendon, with no comparative data available. This study compares ECU stability after subsheath reconstruction, with and without ulnar groove deepening, to stability with an intact subsheath in a cadaveric model., Methods: Position of the ECU tendon relative to the ulnar groove was measured in 5 human cadaveric specimens with the subsheath intact, sectioned, and after 3 reconstruction scenarios: reconstructed, reconstructed with ulnar groove deepened, and ulnar groove deepened with subsheath sectioned. Position of the tendon relative to the radial side of the ulnar groove was recorded with digital calipers in 9 combinations of wrist/forearm positions (wrist flexion, extension, and neutral; forearm pronation, supination, and neutral). Dislocation events, defined as the tendon being completely ulnar to the groove, were recorded., Results: Extensor carpi ulnaris tendon displacement was not significantly different between intact subsheath, subsheath reconstruction, and reconstruction with groove deepening (1.5 mm vs 0.5 mm vs -0.3). Extensor carpi ulnaris tendon displacement after groove deepening with the subsheath sectioned was not significantly different from displacement with a fully sectioned subsheath. Sectioning of the subsheath induced dislocation events of the ECU tendon in multiple positions. Subsheath reconstruction with and without groove deepening allowed no dislocation events., Conclusions: In this cadaveric model, groove deepening did not improve stability of the ECU tendon compared with the reconstructed subsheath, and reconstruction alone was equally effective at eliminating dislocation events., Clinical Relevance: Stabilization techniques that focus on restoration of the important ulnar attachment of the ECU subsheath are favored over routine deepening of the ulnar groove in attempts to stabilize the ECU tendon., (Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background  Central and perpendicular (PERP) screw orientations have each been described for scaphoid fracture fixation. It is unclear, however, which orientation produces greater compression. Questions/Purposes  This study compares compression in scaphoid waist fractures with screw fixation in both PERP and pole-to-pole (PTP) configurations. PERP orientation was hypothesized to produce greater compression than PTP orientation. Methods  Ten preoperative computed tomography scans of scaphoid waist fractures were classified by fracture type and orientation in the coronal and sagittal planes. Three-dimensional models of each scaphoid and fracture plane were created. Simulated Acutrak 2 (Acumed, Hillsboro, OR) screws were placed into the models in both PERP and PTP orientations. Engagement length and screw angle relative to the fracture were measured. Compression strength was calculated from the shear area, average density, and angle acuity. Results  The PTP angle between screw and fracture ranged from 36 to 84 degrees. By definition, the PERP screw-to-fracture angle was 90 degrees. Perpendicularity of the PTP screw to the fracture was positively correlated to compression strength. PERP screws had greater compression than PTP screws when the PTP screw-to-fracture angle was < 80 degrees (106 vs. 80 N), but there was no difference in compression when the PTP screw-to-fracture angle was > 80 degrees, approximating the PERP screw. Conclusion  Increasing screw perpendicularity resulted in higher compression when the screw-to-fracture angle of the PTP screw was < 80 degrees. Maximum compression was obtained with a screw PERP to the fracture. The increased compression gained from PERP screw placement offsets the decreased engagement length. Clinical Relevance  These results provide guidelines for optimal screw placement in scaphoid waist fractures.

The purpose of this preliminary study was to investigate changes in plasma concentrations of zinc-α2-glycoprotein (ZAG), a lipid mobilizing hormone, in obese subjects following Roux-En-Y Gastric Bypass (RYGB) surgery or a very low calorie diet (VLCD). Fasting blood concentrations and anthropometric measurements were measured pre and 12 weeks post intervention. 14 healthy, obese individuals underwent either RYGB (N=6) surgery or a VLCD (N=8). Body composition and fasting plasma ZAG concentrations were measured at baseline (pre) and 12 weeks post intervention (post). At pre-intervention baseline, there was no difference in plasma ZAG between the two intervention groups. Post-intervention, there was a significant overall reduction (F(1,11) = 32.8, p <0.001) in plasma ZAG, which was significant only within the RYGB group from pre to post intervention (33.2 ± 5.7 μg/ml to 26.7 ± 4.8 μg/ml ( p <0.015)) and significantly greater than the change within the VLCD group. The change in ZAG was inversely correlated across groups with BMI reduction (r= -0.60, p <0.05), % body fat reduction (r= -0.68, p <0.015), reduction in weight (r= -0.58, p <0.05), and % weight loss (r= -0.70, p <0.05). Overall, subjects who underwent RYGB or VLCD had a significant reduction in plasma ZAG. This reduction was significant within the RYGB group alone, who lost a larger amount of weight than the VLCD group, which suggests that ZAG may have a protective effect during marked weight loss.

Background: Hand injuries can result in significant time away from competition for professional basketball players. Time to return to play after hand injuries in elite athletes has not been well described., Purpose: To report the return to play from metacarpal fractures, phalangeal fractures, and thumb ligament tears in National Basketball Association (NBA) players over a 5-year period., Study Design: Descriptive epidemiology study., Methods: The NBA transaction report was analyzed from January 2009 to May 2014. Players were identified if they were added to the inactive list (IL), missed games due to their injury, or underwent surgery as a result of hand injury. Number of games missed due to injury, days spent on the IL, and age at injury were calculated by injury type and location., Results: One hundred thirty-seven injuries were identified: 39 injuries to the hand and 98 injuries to the finger. Three major injury patterns were identified and analyzed: metacarpal fractures (n = 26), phalangeal fractures (n = 33), and thumb ligament tears (n = 9). The type of injury sustained affected return to play ( P < .05). All thumb ligament tears required surgery and had the longest return to play of 67.5 ± 17.7 days ( P < .05). The return to play for surgically treated metacarpal fractures (56.7 ± 26.3 days) was significantly greater than nonsurgically treated metacarpal fractures (26.3 ± 12.1 days; P < .01). Return to play for surgically repaired phalangeal fractures (46.2 ± 10.8 days) trended greater but was not significantly different than phalangeal fractures treated nonsurgically (33.3 ± 28.5 days; P = .21)., Conclusion: Hand injuries in professional basketball players can lead to prolonged periods of time away from competition, especially after surgery. This study provides guidelines on expected return to play in the NBA after these common hand injuries., Competing Interests: The authors declared that they have no potential conflicts of interest in the authorship and publication of this contribution.

Purpose: To identify the varying contributions of the proximal and distal portions of the subsheath of the extensor carpi ulnaris (ECU) to its stability, evaluate the correlation of ulnar groove depth and ECU subluxation, and observe the effect of forearm and wrist positions on ECU stability., Methods: Extensor carpi ulnaris tendon position relative to the ulnar groove was measured in 10 human cadaveric specimens with the subsheath intact, partially sectioned (randomized to distal or proximal half), and fully sectioned. Measurements were obtained in 9 positions: forearm supinated, neutral, and pronated and wrist extended, neutral, and flexed. Ulnar groove depth was measured on all specimens., Results: In 7 of 10 specimens with an intact subsheath, the ECU tendon subluxated out of the groove in at least 1 forearm-wrist position. We noted the subluxation of the ECU tendon in all wrist-forearm positions with the exception of pronation-extension in at least 1 specimen. For partial subsheath sectioning, tendon displacement markedly increased after distal subsheath sectioning but not after proximal sectioning. For full subsheath sectioning, wrist flexion produced subluxation in all forearm positions, and forearm supination produced subluxation in all wrist positions. Maximum displacement occurred in supination-flexion. There was no correlation between ulnar groove depth and ECU subluxation., Conclusions: Mild tendon subluxation occurred in the intact specimens in most tested positions. Two positions were remarkable for their consistency in maintaining the tendon within the groove: pronation-neutral and pronation-extension. In fully sectioned specimens, the greatest subluxation occurred in supination-flexion, with supination and flexion independently producing subluxation. Partial sectioning demonstrated that the distal portion of the subsheath played a more important role than the proximal portion in stabilizing the ECU., Clinical Relevance: Subsheath repair or reconstruction should target the distal portion of the subsheath. During postinjury rehabilitation or following surgical reconstruction, combined forearm supination and wrist flexion should be avoided., (Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Acyclic amine-carboxyboranes were effective anti-inflammatory agents in mice at 8 mg/kg x 2. These amine-carboxyboranes were more effective than the standard indomethacin at 8 mg/kg x 2, pentoxifylline at 50 mg/kg x 2, and phenylbutazone at 50 mg/kg x 2. The heterocyclic amine derivatives as well as amine-carbamoylboranes, carboalkoxyboranes, and cyanoboranes were generally less active. However, selected aminomethyl-phosphonate-N-cyanoboranes demonstrated greater than 60% reduction of induced inflammation. The boron compounds were also active in the rat induced edema, chronic arthritis, and pleurisy screens, demonstrating activity similar to the standard indomethacin. The compounds were effecive in reducing local pain and decreased the tail flick reflex to pain. The derivatives which demonstrated good anti-inflammatory activity were effective inhibitors of hydrolytic lysosomal, and proteolytic enzyme activities with IC(50) 50 values equal to (-6)M in mouse macrophages, human leukocytes, and Be Sal osteofibrolytic cells. In these same cell lines, the agents blocked prostaglandin cyclooxygenase activity with IC(50) values of (-6)M. In mouse macrophage and human leukocytes, 5' lipoxygenase activity was also inhibited by the boron derivatives with IC(50) values of 10(-6)M. These IC(50) values for inhibition of these enzyme activities are consistent with published values of known anti-inflammatory agents which target these enzymes.

The metal complexes of amine-carboxyborane including copper, chromium, zinc, calcium amd cobalt were effective hypolipidemic agents lowering both serum cholesterol and triglyceride levels significantly in mice at 8 mg/kg/day, I.P. after 16 days. The agents reduced acetyl CoA synthetase, ATP-dependent citrate lyase, acyl CoA cholesterol acyl transferase, sn-glycerol-3-phosphate acyl transferase activities of rat liver and small intestinal mucosa after 14 days treatment. The neutral cholesterol ester hydrolase activity was elevated by the agents in both tissues. The metal complexes altered lipid levels in the bile of rats after treatment as well as the bile acid composition after 14 days administration, orally. The agents blocked enterohepatic absorption of cholesterol from rat isolated intestinal loops.

A series of tricyclohexyl- and triphenylphosphine boranes, carboxyboranes and cyanoboranes were synthesized. These compounds have potent hypolipidemic effects, antineoplastic and antiinflammatory activities in rodents. Furthermore, they demonstrated potent cyctotoxicity against standard human tissue culture lines. The compounds which afforded the best hypolipidemic activity, i.e. greater than 40% reduction of serum cholesterol and triglyceride levels, were diphenyl-(4-methylphenyl)-phosphine borane and triphenylphosphine carboxyborane. Other derivatives demonstrated more potent antineoplastic activity against the Ehrlich ascites carcinoma growth including triphenylphosphine cyanoborane, 2-amino-4-methyl-pyridine cyanoborane and 2-amino-pyridine cyanoborane. Most of the derivatives showed good activity against murine L1210 lymphoid leukemia, Tmolt3 human leukemia, uterine HeLaS cells, and human glioma cell growth. Select compounds were active against colon adenocarcinoma, KB nasopharynx, lung bronchogenic and osteosarcoma cell growth. Tricyclohexyl- and triphenylphosphine boranes and the carboxy derivatives of the latter borane demonstrated good antiinflammatory activity.

Boron analogues of phosphonoacetates proved to be potent hypolipidaemic agents in rodents, lowering both serum cholesterol and triglyceride levels. (C2H5O)3PBH2COOCH3 proved to be the most effective agent in mice, lowering serum cholesterol 46% and serum triglycerides 54% after 16 days. (C2H5O)3PBH2COOH and Na+H+(C2H5O)2(-O)PBH2COO- caused greater than a 40% reduction in lipids. The cyanoborane adducts of aminomethylphosphonates were generally less effective; (C6H5O)2P(O)CH2NH2BH2CN was the most effective, lowering serum cholesterol 32% and serum triglycerides 43% after 16 days. The phosphonoacetates appeared to lower lipid concentrations by several mechanisms. First, they lowered the de novo synthesis of cholesterol and triglycerides in the liver. Second, they accelerated the excretion of lipids into the bile and faeces. Thirdly, they modulated LDL and HDL-cholesterol contents in a manner which suggests they reduced the deposition of lipids in peripheral tissues, and accelerated the movement of cholesterol from tissues (e.g. plaques) to the liver for excretion into the bile.

The amine-cyanoboranes, the amine-cyanoalkylboranes and the aminomethyl-phosphonate-N-cyanoborane adducts proved to be active antineoplastic agents. These compounds were more effective against single cell cultured cell growth rather than solid tumors. The following amine-cyanoboranes, (CH3)2(C18H37)NBH2CN (5), (CH3)2NHBH[CH(CH3)2]CN (7) and (CH3)3NB(CN)2.CH3 (10), were the most active in vivo and in vitro. A related phosphine-cyanoborane was also very active in both in vivo and in vitro model screens. Of the amino-methyl-phosphonate-N-cyanoborane adducts, (CH3O)2.P(O)CH2N(C2H5)2BH2CN (13) proved to be the most active. The amine-cyanoalkylboranes had the poorest in vivo activity; the in vitro cytotoxicity, however, was similar to that of other cyanoboranes.