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Lateral decubitus single position anterior-posterior (AP) fusion utilizing anterior lumbar interbody fusion and percutaneous posterior fixation is a novel, minimally invasive surgical technique. Single position lumbar surgery (SPLS) with anterior lumbar interbody fusion (ALIF) or lateral lumbar interbody fusion (LLIF) has been shown to be a safe, effective technique. This study directly compares perioperative outcomes of SPLS with lateral ALIF vs. traditional supine ALIF with repositioning (FLIP) for degenerative pathologies.To determine if SPLS with lateral ALIF improves perioperative outcomes compared to FLIP with supine ALIF.Multicenter retrospective cohort study.Patients undergoing primary AP fusions with ALIF at 5 institutions from 2015 to 2020.Levels fused, inclusion of L4-L5, L5-S1, radiation dosage, operative time, estimated blood loss (EBL), length of stay (LOS), perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), and PI-LL mismatch.Retrospective analysis of primary ALIFs with bilateral percutaneous pedicle screw fixation between L4-S1 over 5 years at 5 institutions. Patients were grouped as FLIP or SPLS. Demographic, procedural, perioperative, and radiographic outcome measures were compared using independent samples t-tests and chi-squared analyses with significance set at p.05. Cohorts were propensity-matched for demographic or procedural differences.A total of 321 patients were included; 124 SPS and 197 Flip patients. Propensity-matching yielded 248 patients: 124 SPLS and 124 FLIP. The SPLS cohort demonstrated significantly reduced operative time (132.95±77.45 vs. 261.79±91.65 min; p0.001), EBL (120.44±217.08 vs. 224.29±243.99 mL; p.001), LOS (2.07±1.26 vs. 3.47±1.40 days; p.001), and rate of perioperative ileus (0.00% vs. 6.45%; p =.005). Radiation dose (39.79±31.66 vs. 37.54±35.85 mGy; p =.719) and perioperative complications including vascular injury (1.61% vs. 1.61%; p =.000), retrograde ejaculation (0.00% vs. 0.81%, p =.328), abdominal wall (0.81% vs. 2.42%; p =.338), neuropraxia (1.61% vs. 0.81%; p =.532), persistent motor deficit (0.00% vs. 1.61%; p =.166), wound complications (1.61% vs. 1.61%; p =.000), or VTE (0.81% vs. 0.81%; p =.972) were similar. No difference was seen in 90-day return to OR. Similar results were noted in sub-analyses of single-level L4-L5 or L5-S1 fusions. On radiographic analysis, the SPLS cohort had greater changes in LL (4.23±11.14 vs. 0.43±8.07 deg; p =.005) and PI-LL mismatch (-4.78±8.77 vs. -0.39±7.51 deg; p =.002).Single position lateral ALIF with percutaneous posterior fixation improves operative time, EBL, LOS, rate of ileus, and maintains safety compared to supine ALIF with prone percutaneous pedicle screws between L4-S1.

Background The gut microbiome is a diverse network of bacteria which inhabit our digestive tract and is crucial for efficient cellular metabolism, nutrient absorption, and immune system development. Spinal cord injury (SCI) disrupts autonomic function below the level of injury and can alter the composition of the gut microbiome. Studies in rodent models have shown that SCI-induced bacterial imbalances in the gut can exacerbate the spinal cord damage and impair recovery. In this study we, for the first time, characterized the composition of the gut microbiome in a Yucatan minipig SCI model. We compared the relative abundance of the most dominant bacterial phyla in control samples to those collected from animals who underwent a contusion-compression SCI at the 2nd or 10th Thoracic level. Results We identify specific bacterial fluctuations that are unique to SCI animals, which were not found in uninjured animals given the same dietary regimen or antibiotic administration. Further, we identified a specific time-frame, “SCI-acute stage”, during which many of these bacterial fluctuations occur before returning to “baseline” levels. Conclusion This work presents a dynamic view of the microbiome changes that accompany SCI, establishes a resource for future studies and to understand the changes that occur to gut microbiota after spinal cord injury and may point to a potential therapeutic target for future treatment.

Acetabular fracture open reduction and internal fixation (ORIF) is generally associated with high intraoperative blood loss. Hypotensive anesthesia has been shown to decrease blood loss and intraoperative transfusion in total joint arthroplasty and posterior spinal fusion. In this study, we assessed the effect of reduction in intraoperative mean arterial pressures (MAPs) during acetabular fracture surgery on intraoperative blood loss and need for transfusion.Three hundred and one patients with acetabular fractures who underwent ORIF at an academic Level 1 trauma center were retrospectively reviewed. Patients were separated based on mean intraoperative MAPs (60 mmHg, 60-70 mmHg,70 mmHg). Thirteen patients had mean intraoperative MAP60 mmHg, 95 had MAP 60-70 mmHg, and 193 had MAP70 mmHg. Rates of intraoperative and postoperative allogeneic blood transfusion were compared.Mean intraoperative MAPs were significantly different between groups (p0.0001). Time from injury to surgery, estimated blood loss, operative time and intraoperative IV fluids were comparable. The proportion of patients who received blood transfusion and mean units transfused intraoperatively and postoperatively were similar between groups. Mean differences in preoperative and postoperative hemoglobin and hematocrit were also similar. There was no difference in hospital length of stay or perioperative complications between the groups. Multivariate logistic regression analysis demonstrated that body mass index30 (p0.05) and anterior surgical approach (p0.01) were independently associated with intraoperative transfusion and an anterior surgical approach (p0.001) was independently associated with postoperative transfusion.Decreased intraoperative MAP during acetabular fracture surgery does not reduce blood loss or need for transfusion. On the other hand, no increased end-organ ischemia was seen with hypotensive anesthesia.Therapeutic Level III.

Tranexamic acid (TXA) reduces need for transfusion in total joint arthroplasty, though findings in acetabular surgery are conflicting. We compared outcomes after acetabular fracture surgery with or without perioperative intravenous (IV) TXA administration. We performed a retrospective review of 305 patients with acetabular fractures that underwent open reduction and internal fixation (ORIF). Eighty-nine patients received TXA, and 216 did not. The primary outcome was rates of intraoperative and postoperative allogeneic blood transfusion. Baseline demographics and characteristics were similar. Time from injury to surgery and estimated blood loss were comparable. Operative time (p

Achieving durable mechanical stability in geriatric intertrochanteric proximal femur fractures remains a challenge. Concomitant poor bone quality, unstable fracture patterns, and suboptimal reduction are additional risk factors for early mechanical failure. Cement augmentation of the proximal locking screw or blade is one proposed method to augment implant anchorage. The purpose of this review is to describe the biomechanical and clinical evidence for cement augmentation of geriatric intertrochanteric fractures, and to elaborate indications for cement augmentation. The PubMed database was searched for English language studies up to January 2021. Studies that assessed effect of calcium phosphate or methylmethacrylate cement augmentation during open reduction and internal fixation of intertrochanteric fractures were included. Studies with sample size

Excessive fracture site collapse and shortening in intertrochanteric femur fractures alter hip biomechanics and patient outcomes. The purpose of the study was to compare extent of collapse in cephalomedullary nails with blades or lag screws. We hypothesized that there would be no difference in collapse between helical blades and lag screws. Retrospective cohort study. Single U.S. Level I Trauma Center. 171 consecutive patients treated with cephalomedullary nails with either lag screw or blade for AO/OTA 31A1-3 proximal femur fractures and minimum 3-month follow-up. Lag screw or helical blade in a cephalomedullary nail. The primary outcome was fracture site collapse at 3 months. There was a significantly higher proportion of reverse-oblique and transverse intertrochanteric femur fractures (31-A3) in the lag screw group (15/42 vs 25/129). A3 patterns were associated with more collapse. There was significantly less collapse in the blade group (median 4.7 mm, inter-quartile range 2.5–7.8 mm) than the screw group (median 8.4 mmm, inter-quartile range 3.7–11.2 mm, p 0.006). Median collapse was no different between blades and screws when comparing stable and unstable patterns. However, blades were independently associated with 2.5 mm less collapse (95%CI − 4.2, − 0.72 mm, p 0.006) and lower likelihood of excessive collapse (> 10 mm at 3 months, OR 0.3, 95% CI 0.13–0.74, p 0.007), regardless of fracture pattern. Helical blades are independently associated with significantly less collapse than lag screws in intertrochanteric proximal femur fractures, after adjusting for unstable fracture patterns. In fracture patterns at risk for collapse, surgeons can consider use of a helical blade due to its favorable sliding properties compared to screws.

The primary aim of this study was to compare clinical outcomes in patients with associated both column (ABC) acetabular fractures with fracture of the posterior wall (PW), in which the PW underwent reduction and fragment-specific fixation versus those that were treated with column fixation alone. Secondary aims were to assess PW fracture incidence and morphology, as well as to compare radiographic outcomes including fracture healing and interval displacement of the PW in those that did and did not undergo fragment-specific fixation of the PW. This was a retrospective series of ABC acetabular fractures treated at a single Level I trauma center. Separate fractures of the PW were identified, and associated features were assessed. Associated both column fractures that underwent reduction and fragment-specific fixation of the PW where then compared to ABC fractures with PW involvement that underwent column reconstruction alone. Radiographic and clinical outcomes were compared. Fractures of the PW occurred in 55.7% of ABC fractures and were associated with central displacement of the femoral head. The majority of PW fractures were large and involved the acetabular roof. All PW fractures healed without displacement by 3 months, regardless of whether or not reduction and stabilization was performed. Mid-term outcomes at 1-year were similar regardless of whether or not the PW was reduced and stabilized, with regards to Tonnis grade, Merle d'Aubigne-Postel score, and conversion to total hip arthroplasty. Reduction and fragment-specific fixation of the PW component of ABC acetabular fractures did not improve outcomes in this small comparative study. Posterior wall fractures associated with ABC patterns are frequently large-sized fragments that involve the acetabular roof and are rendered stable after reconstruction of the columns.

One of the only currently available treatment options to potentially improve neurological recovery after acute spinal cord injury (SCI) is augmentation of mean arterial blood pressure (MAP) to promote blood flow and oxygen delivery to the injured cord. However, to optimize such hemodynamic management, clinicians require a method to monitor the physiological effects of these MAP alterations within the injured cord. Therefore, we investigated the feasibility and effectiveness of using a novel optical sensor, based on near-infrared spectroscopy (NIRS), to monitor real-time spinal cord oxygenation and hemodynamics during the first 7 days post-injury in a porcine model of acute SCI. Six Yucatan miniature pigs underwent a T10 vertebral level contusion-compression injury. Spinal cord oxygenation and hemodynamics were continuously monitored by a minimally invasive custom-made NIRS sensor, and by invasive intraparenchymal (IP) probes to validate the NIRS measures. Episodes of MAP alteration and hypoxia were performed acutely after injury, and at 2 and 7 days post-injury to simulate the types of hemodynamic changes SCI patients experience after injury. The NIRS sensor demonstrated the ability to provide oxygenation and hemodynamic measurements over the 7-day post-SCI period. NIRS measures showed statistically significant correlations with each of the invasive IP measures and MAP changes during episodes of MAP alteration and hypoxia throughout the first week post-injury (

Chronic high-thoracic and cervical spinal cord injury (SCI) results in a complex phenotype of cardiovascular consequences, including impaired left ventricular (LV) contractility. Here, we aim to determine whether such dysfunction manifests immediately post-injury, and if so, whether correcting impaired contractility can improve spinal cord oxygenation (SCO2), blood flow (SCBF) and metabolism. Using a porcine model of T2 SCI, we assess LV end-systolic elastance (contractility) via invasive pressure-volume catheterization, monitor intraparenchymal SCO2 and SCBF with fiberoptic oxygen sensors and laser-Doppler flowmetry, respectively, and quantify spinal cord metabolites with microdialysis. We demonstrate that high-thoracic SCI acutely impairs cardiac contractility and substantially reduces SCO2 and SCBF within the first hours post-injury. Utilizing the same model, we next show that augmenting LV contractility with the β-agonist dobutamine increases SCO2 and SCBF more effectively than vasopressor therapy, whilst also mitigating increased anaerobic metabolism and hemorrhage in the injured cord. Finally, in pigs with T2 SCI survived for 12 weeks post-injury, we confirm that acute hemodynamic management with dobutamine appears to preserve cardiac function and improve hemodynamic outcomes in the chronic setting. Our data support that cardio-centric hemodynamic management represents an advantageous alternative to the current clinical standard of vasopressor therapy for acute traumatic SCI., Clinical neuroprotective strategies for acute spinal cord injury (SCI) have largely overlooked the heart. Here the authors show cardiac contractility is immediately impaired in a porcine model of T2 SCI, and cardio-centric treatment with dobutamine optimizes cord oxygenation and mitigates haemorrhage.

Intra-articular screw cut-out is a potential complication of intertrochanteric femur fracture fixation with a cephalomedullary nail. Cement augmentation of fixation in the proximal segment offers the prospect of increased stability and fewer complications, but clinical experience with non-resorbable cement is limited. To determine the handling properties and efficacy of this new technique, we performed a retrospective propensity-matched cohort of forty-four geriatric intertrochanteric femur fractures treated with a cephalomedullary nail with (n = 11) or without (n = 33) augmentation with non-resorbable cement injected into the proximal segment. In the patients treated with cement augmentation, at minimum 3-month follow-up, there were no instances of intra-articular cut-out, and no increase in re-operation compared to conventional fixation. Cement augmentation appears to be safe and effective in geriatric intertrochanteric femur fractures to mitigate risk of cut-out.

This study examined osteotomy union and heterotopic ossification (HO) after performing digastric trochanteric osteotomies during open reduction and internal fixation (ORIF) of acetabular and combined femoral head fractures. Femoral head osteonecrosis and trochanteric screw removal were secondarily assessed. Twenty-six patients treated at a Level I trauma center, from years 2003 to 2019, who received a digastric trochanteric osteotomy during acetabular and combined femoral head fracture ORIF through a posterior surgical approach were retrospectively identified. Osteotomies were fixed with two 3.5 mm cortical lag screws. Rates of osteotomy union, HO, femoral head osteonecrosis, and trochanteric screw removal were determined. All osteotomies went onto union without displacement or failure of fixation. Only three (12%) patients developed severe HO (modified-Brooker class III–IV). There were no instances of femoral head osteonecrosis and only one (7%) patient required trochanteric screw removal. The digastric trochanteric osteotomy heals reliably with low rates of severe HO, femoral head osteonecrosis, and screw removal for soft-tissue irritation. A review of the literature is presented and found comparable findings.

One of the challenges associated with conducting experiments in animal models of traumatic spinal cord injury (SCI) is inducing a consistent injury with minimal variability in the degree of tissue damage and resultant behavioral and biochemical outcomes. We evaluated how the variability in morphometry of the spinal cord and surrounding cerebrospinal fluid (CSF) contributes to the variability in behavioral and histological outcomes in our porcine model of SCI. Using intraoperative ultrasound imaging, spinal cord morphometry was assessed in seven Yucatan minipigs undergoing a weight-drop T10 contusion-compression injury. Bivariate and multi-variate analysis and modeling were used to identify native morphometrical determinants of interanimal variability in histological and behavioral outcomes. The measured biomechanical impact parameters did not correlate with the histological measures or hindlimb locomotor behavior (Porcine Thoracic Injury Behavior Scale). In contrast, clear associations were revealed between CSF layer morphometry and the amount of white matter and tissue sparing. Specifically, the dorsoventral diameter of the dural sac and ventral CSF space were strong predictors of behavioral and histological outcome and together explained ≥95.0% of the variance in these parameters. In addition, a dorsoventral diameter of the spinal cord less than 5.331 mm was a strong contributing factor to poor behavioral recovery over 12 weeks. These results indicate that interanimal variability in cord morphometry provides a potential biological explanation for the observed heterogeneity in histological and behavioral outcomes. Such knowledge is helpful for appropriately balancing experimental groups, and/or varying impact parameters to match cord and CSF layer dimensions for future studies.

STUDY DESIGN This was a retrospective comparative study. OBJECTIVE The objective of this study was to assess the effect of increased age on perioperative and postoperative complication rates, reoperation rates, and patient-reported pain and disability scores after lateral lumbar interbody fusion (LLIF). SUMMARY OF BACKGROUND DATA LLIF was developed to minimize soft tissue trauma and reduce the risk of vascular injury; however, there is little evidence regarding the effect of advanced age on outcomes of LLIF. METHODS Patients who underwent LLIF from 2009 to 2019 at one institution with a minimum 6-month follow-up were retrospectively reviewed. Patients less than 18 years old with musculoskeletal tumor or trauma were excluded. The primary outcome was the preoperative to postoperative change in the Numeric Pain Rating Scale (NPRS) for back pain. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and change in Oswestry Disability Index were also evaluated. Relationships with age were assessed both with age as a continuous variable and segmenting by age below 70 versus 70+. RESULTS In total, 279 patients were included. The median age was 65±13 years and 159 (57%) were female. Age was not related to improvements in back NPRS and Oswestry Disability Index. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and radiographic fusion rate also were not related to age. After multivariable risk adjustment, increasing age was associated with greater improvements in back NPRS. The decrease in back NPRS was 0.68 (95% confidence interval: 0.14, 1.22; P=0.014) points greater for every 10-year increase in age. Age was not associated with rates of complication, readmission, or reoperation. CONCLUSIONS LLIF is a safe and effective procedure in the elderly population. Advanced age is associated with larger improvements in preoperative back pain. Surgeons should consider the benefits of LLIF and other minimally invasive techniques when evaluating elderly candidates for lumbar fusion. LEVEL OF EVIDENCE Level III.

BackgroundLeiomyosarcomas (LMS) are a heterogenous group of malignant mesenchymal neoplasms with smooth muscle origin and are classified as either non-uterine (NULMS) or uterine (ULMS). Metastatic pattern, prognostic factors, and ideal staging/surveillance studies for truncal and extremity LMS have not been defined.MethodsA retrospective analysis of patients diagnosed with histopathology-confirmed truncal or extremity LMS between 2009-2019 was conducted. Data collected included demographics, tumor characteristics, staging, surveillance, and survival endpoints. Primary site was defined as either 1. Extremity, 2. Flank/Pelvis, or 3. Chest wall/Spine.ResultsWe identified 73 patients, 23.3% of which had metastatic LMS at primary diagnosis, while 68.5% developed metastatic disease at any point. The mean metastatic-free survival from primary diagnosis of localized LMS was 3.0±2.8 years. Analysis of prognostic factors revealed that greater age (≥50 years) at initial diagnosis (OR=3.74, p=0.0003) and higher tumor grades II (OR=16, p=0.019) and III (OR=13, p=0.025) were significantly associated with metastases.ConclusionsTruncal and peripheral extremity LMS is an aggressive tumor with high metastatic potential. While there is a significant risk of metastases to lungs, extra-pulmonary tumors are relatively frequent. Older patients and patients with higher-grade (II/III) tumors carry an increased risk of developing metastatic disease.

After acute traumatic spinal cord injury (SCI), the spinal cord can swell to fill the subarachnoid space and become compressed by the surrounding dura. In a porcine model of SCI, we performed a duraplasty to expand the subarachnoid space around the injured spinal cord and evaluated how this influenced acute intraparenchymal hemodynamic and metabolic responses, in addition to histological and behavioral recovery. Female Yucatan pigs underwent a T10 SCI, with or without duraplasty. Using microsensors implanted into the spinal cord parenchyma, changes in blood flow (ΔSCBF), oxygenation (ΔPO

Stroke is a leading cause of long-term disability and death in the united states. The development of new therapies for stroke are sorely needed. There is great hope that stem cell therapy will create a paradigm shift in the treatment of stroke patients. A barrier to ensuring clinical success of stem cell therapy is the paucity of understanding of the mechanisms by which stem cells exert their beneficial effects. Using a novel mRNA purification method, we identified 50 genes encoding extracellular space proteins, expressed by human neural stem cells (hNSCs) whose expression positively correlated with functional recovery. In this study, we focus on one of the paracrine factors from grafted hNSCs that correlated best with functional recovery, to investigate its therapeutic potential in promoting recovery after stroke. Male nude rats underwent stroke using the distal middle cerebral artery occlusion (dMCAo) model. One week following stroke, osmotic pumps were prepared and loaded with recombinant MTN-2. The osmotic pumps were inserted into the peri-infarct area and infused recombinant MTN-2 for 5 days. Post-stroke, animals were assessed for functional recovery for 5 weeks using both the Montoya staircase test and the whisker-paw reflex test to assess for forelimb function, dexterity, side bias, and placing deficits. After 5 weeks, brain tissue was isolated to assess glial cell morphology. Brain sections were stained with GFAP and IBA1 to visualize astrocytes and microglia, respectively. Confocal images were processed and analyzed using the Bitplane Imaris image analysis software. Output measurements of number of cells/mm2, cell volume, cell branching, and process length and thickness were obtained to characterize the changes in astrocytic and microglial response to injury and paracrine factor treatment. By identifying paracrine factors that are responsible for the regeneration of brain tissue following implantation of hNSCs in stroke brain, this work will increase the likelihood of successful clinical translation of stem cell therapy for stroke. Moreover, elucidating these molecular pathways important for brain recovery may ultimately identify novel therapeutic targets and offer hope to millions of Americans who live with the devastating effects of stroke.

Moyamoya disease (MMD) is a progressive, occlusive disease of the internal carotid arteries and their proximal branches, with the subsequent development of an abnormal vascular network of small, weak blood vessels that are prone to rupture. Steno-occlusive changes in the posterior cerebral arteries (PCA) may contribute to worse outcomes in MMD patients, however, there is a paucity of information on the incidence and natural history of MMD patients with PCA disease. We retrospectively reviewed the charts of patients with MMD treated between 1987 and 2019. Demographics, peri-operative outcomes, and radiological phenotypes were recorded for 450 patients. PCA disease was scored as either 0 (no disease), 1 (mild), 2 (moderate), or 3 (severe, or occluded). Out of 450 patients, 164 (34.4%) had concurrent PCA disease. In patients with PCA disease, the extent of occlussion was mild in 56 (34%), moderate in 41 (25%), and severe in 67 (40.9%) patients. In total, there were 319 females (70.9%), with a higher proportion of female MMD patients having severe or moderate PCA disease (p=0.038). Patients with severe and moderate PCA disease had higher Suzuki grades (p Over a mean follow-up of 6.94±4.16 years, 28 patients (8.86%) developed new or progressive PCA disease. Bilateral disease was present in 66 patients (14.7%) and was associated with higher Suzuki grades (p PCA disease involvement is associated with higher rates of ischemic peri-operative complications and poor functional outcomes likely due to reduced collateral flow. Progression of PCA disease is not uncommon. Future studies are needed to assess the impact of PCA disease progression on long-term outcomes.

BACKGROUND CONTEXT Lateral decubitus single position anterior-posterior (AP) fusion utilizing anterior lumbar interbody fusion and percutaneous posterior fixation (SPS) is a novel, Minimally Invasive Surgical technique. Single position AP fusion with anterior or lateral interbodies has been shown to be a safe, effective technique to treat of lumbar degenerative disease. This study directly compares perioperative outcomes of SPS vs FLIP for degenerative pathologies. PURPOSE To determine if SPS with lateral ALIF (LALIF) improves perioperative outcomes compared to FLIP patients. STUDY DESIGN/SETTING Multicenter retrospective cohort study. PATIENT SAMPLE A total of 321 patients undergoing primary AP fusions with ALIF and bilateral percutaneous pedicle screw fixation at 5 institutions from 2015 to 2020. OUTCOME MEASURES Levels fused, inclusion of L4-L5, L5-S1, radiation dosage, operative time, estimated blood loss (EBL), length of stay (LOS), perioperative complications and radiographic outcomes. METHODS Retrospective analysis of primary ALIFs with bilateral percutaneous pedicle screw fixation between L4-S1 over 5 years at 5 institutions. Patients were grouped as FLIP or SPS. Outcome measures: levels fused, inclusion of L4-L5, L5-S1, radiation dosage, operative time, estimated blood loss (EBL), length of stay (LOS), perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), and PI-LL mismatch. Measures were compared using independent samples t-tests and chi-squared analyses, significance set at p RESULTS A total of 321 patients: 124 SPS, 197 Flip were identified. PSM was performed due to differences between groups in levels fused, and proportion involving L4-5, yielding 248 patients: 124 SPS, 124 FLIP. The SPS cohort demonstrated significantly reduced OpTime (132.95±77.45 vs 261.79±91.65 min; p CONCLUSIONS Single position lateral ALIF with percutaneous posterior fixation improves operative efficiency, EBL, LOS, rate of ileus and maintains safety compared to supine ALIF with prone percutaneous pedicle screws between L4-S1. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

There is an increasing need to develop approaches that will not only improve the clinical management of neurogenic lower urinary tract dysfunction (NLUTD) after spinal cord injury (SCI), but also advance therapeutic interventions aimed at recovering bladder function. Although pre-clinical research frequently employs rodent SCI models, large animals such as the pig may play an important translational role in facilitating the development of devices or treatments. Therefore, the objective of this study was to develop a urodynamics protocol to characterize NLUTD in a porcine model of SCI. An iterative process to develop the protocol to perform urodynamics in female Yucatan minipigs began with a group of spinally intact, anesthetized pigs. Subsequently, urodynamic studies were performed in a group of awake, lightly restrained pigs, before and after a contusion-compression SCI at the T2 or T9-T11 spinal cord level. Bladder tissue was obtained for histological analysis at the end of the study. All anesthetized pigs had bladders that were acontractile, which resulted in overflow incontinence once capacity was reached. Uninjured, conscious pigs demonstrated appropriate relaxation and contraction of the external urethral sphincter during the voiding phase. SCI pigs demonstrated neurogenic detrusor overactivity and a significantly elevated post-void residual volume. Relative to the control, SCI bladders were heavier and thicker. The developed urodynamics protocol allows for repetitive evaluation of lower urinary tract function in pigs at different time points post-SCI. This technique manifests the potential for using the pig as an intermediary, large animal model for translational studies in NLUTD.

SUMMARY Pilon fractures are complex injuries to the tibial plafond requiring stable fixation in the setting of effective soft tissue management, particularly in high-energy injuries, open fractures, or in geriatric individuals. Medial column support of the distal tibial metaphysis is often an essential component when applying balanced fixation. However, the biologic implications of multiple surgical approaches in the setting of damaged tissue, devitalized bone, or significant bone loss may contribute to increased complications. Percutaneous intramedullary large fragment screws offer both stability and a soft tissue-friendly approach for stabilizing the medial column. Here, we present our technique and indications for medial column support in pilon fractures using percutaneous large fragment fixation, along with our early clinical experience in a case series of 7 patients. At minimum 6-month follow-up, all patients healed their injuries with maintained alignment and without complications or further reoperation. Medial column support with percutaneous large fragment fixation in pilon fractures is a viable option to provide mechanical stability while effectively managing tenuous soft tissue envelopes.

OBJECTIVES To compare rates of heterotopic ossification (HO) after acetabular fracture surgery, through a posterior approach, with and without gluteus minimus muscle (GMM) debridement. DESIGN Retrospective comparative study. SETTING Single academic Level I trauma center. PATIENTS Ninety-four patients in the GMM preserved group and 42 patients in the GMM debrided group met inclusion criteria. INTERVENTION GMM preservation or debridement during acetabular fracture surgery through a single-posterior approach. MAIN OUTCOME MEASUREMENTS Primary outcomes were incidence and severity of HO. Reoperation for HO excision was assessed. Other risk factors for severe HO (Brooker class III-IV) were secondarily assessed using multivariable logistic regression analyses. Odds ratios (ORs) with 95% confidence intervals were calculated. The significance was set at P-value ≤ 0.05. RESULTS There was no difference in the incidence or severity of HO between the debrided and preserved groups. Rates of reoperation for HO excision were comparable. American Society of Anesthesiologists physical status class (OR = 3.3), head injury (OR = 4.6), and abdominal injury (OR = 4.5) were associated with severe HO. CONCLUSION GMM debridement was not associated with a decreased incidence of HO after acetabular fracture surgery. American Society of Anesthesiologists class is a novel risk factor associated with severe HO formation. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVES To determine the incidence of iatrogenic peroneal nerve palsy after application of an intraoperative lateral distractor during open reduction and internal fixation of tibial plateau fractures. DESIGN Retrospective review. SETTING Single academic Level I trauma center. PATIENTS One hundred forty-seven patients met criteria and were included in the study. INTERVENTION Patients with unicondylar and bicondylar tibial plateau fractures underwent open reduction and internal fixation and received application of an intraoperative lateral distractor to aid in visualization and reduction of the impacted lateral plateau. MAIN OUTCOME MEASUREMENTS Incidence of iatrogenic peroneal nerve palsy. RESULTS There was a 2.0% incidence of iatrogenic peroneal nerve symptoms (3 of 147 patients), most of which were incomplete sensory deficits. There was no association with staged external fixation, regional anesthesia, or tourniquet use. CONCLUSION Use of an intraoperative lateral distractor is safe and has a low incidence of iatrogenic peroneal nerve palsy if applied carefully. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Therapeutic development for spinal cord injury is hindered by the difficulty in conducting clinical trials, which to date have relied solely on functional outcome measures for patient enrollment, stratification, and evaluation. Biological biomarkers that accurately classify injury severity and predict neurologic outcome would represent a paradigm shift in the way spinal cord injury clinical trials could be conducted. MicroRNAs have emerged as attractive biomarker candidates due to their stability in biological fluids, their phylogenetic similarities, and their tissue specificity. Here we characterized a porcine model of spinal cord injury using a combined behavioural, histological, and molecular approach. We performed next-generation sequencing on microRNAs in serum samples collected before injury and then at 1, 3, and 5 days post injury. We identified 58, 21, 9, and 7 altered miRNA after severe, moderate, and mild spinal cord injury, and SHAM surgery, respectively. These data were combined with behavioural and histological analysis. Overall miRNA expression at 1 and 3 days post injury strongly correlates with outcome measures at 12 weeks post injury. The data presented here indicate that serum miRNAs are promising candidates as biomarkers for the evaluation of injury severity for spinal cord injury or other forms of traumatic, acute, neurologic injury.

In the military environment, injured soldiers undergoing medical evacuation via helicopter or mine-resistant ambush-protected vehicle (MRAP) are subjected to vibration and shock inherent to the transport vehicle. We conducted the present study to assess the consequences of such vibration on the acutely injured spinal cord. We used a porcine model of spinal cord injury (SCI). After a T10 contusion-compression injury, animals were subjected to 1) no vibration (n = 7-8), 2) whole body vibration at frequencies and amplitudes simulating helicopter transport (n = 8), or 3) whole body vibration simulating ground transportation in an MRAP ambulance (n = 7). Hindlimb locomotor function (using Porcine Thoracic Injury Behavior Scale [PTIBS]), Eriochrome Cyanine histochemistry and biochemical analysis of inflammatory and neural damage markers were analyzed. Cerebrospinal fluid (CSF) expression levels for monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6, IL-8, and glial fibrillary acidic protein (GFAP) were similar between the helicopter or MRAP group and the unvibrated controls. Spared white/gray matter tended to be lower in the MRAP-vibrated animals than in the unvibrated controls, especially rostral to the epicenter. However, spared white/gray matter in the helicopter-vibrated group appeared normal. Although there was a relationship between the extent of sparing and the extent of locomotor recovery, no significant differences were found in PTIBS scores between the groups. In summary, exposures to vibration in the context of ground (MRAP) or aeromedical (helicopter) transportation did not significantly impair functional outcome in our large animal model of SCI. However, MRAP vibration was associated with increased tissue damage around the injury site, warranting caution around exposure to vehicle vibration acutely after SCI.

Spinal cord injury (SCI) is a devastating neurological condition for which there are currently no effective treatment options to restore function. A major obstacle to the development of new therapies is our fragmentary understanding of the coordinated pathophysiological processes triggered by damage to the human spinal cord. Here, we describe a systems biology approach to integrate decades of small-scale experiments with unbiased, genome-wide gene expression from the human spinal cord, revealing a gene regulatory network signature of the pathophysiological response to SCI. Our integrative analyses converge on an evolutionarily conserved gene subnetwork enriched for genes associated with the response to SCI by small-scale experiments, and whose expression is upregulated in a severity-dependent manner following injury and downregulated in functional recovery. We validate the severity-dependent upregulation of this subnetwork in rodents in primary transcriptomic and proteomic studies. Our analysis provides systems-level view of the coordinated molecular processes activated in response to SCI.

Traumatic spinal cord injury (SCI) research has recently focused on the use of rat and mouse models for in vivo SCI experiments. Such small rodent SCI models are invaluable for the field, and much has been discovered about the biologic and physiologic aspects of SCI from these models. It has been difficult, however, to reproduce the efficacy of treatments found to produce neurologic benefits in rodent SCI models when these treatments are tested in human clinical trials. A large animal model may have advantages for translational research where anatomical, physiological, or genetic similarities to humans may be more relevant for pre-clinically evaluating novel therapies. Here, we review the work carried out at the University of British Columbia (UBC) on a large animal model of SCI that utilizes Yucatan miniature pigs. The UBC porcine model of SCI may be a useful intermediary in the pre-clinical testing of novel pharmacological treatments, cell-based therapies, and the "bedside back to bench" translation of human clinical observations, which require preclinical testing in an applicable animal model.

There are currently no therapeutic interventions available for the treatment of spinal cord injury (SCI). The discovery and validation of the growing number of promising therapies will require continued reliance on preclinical animal models of SCI prior to human translation. Animal models of SCI are instrumental in better understanding the mechanisms involved in traumatic SCI and evaluating the efficacy of therapeutic interventions. Over the past 40 years, substantial gains have been made in developing consistent, reproducible and reliable animal SCI models.

Spinal cord injury (SCI) researchers have predominately utilized rodents and mice for in vivo SCI modeling and experimentation. From these small animal models have come many insights into the biology of SCI, and a growing number of novel treatments that promote behavioral recovery. It has, however, been difficult to demonstrate the efficacy of such treatments in human clinical trials. A large animal SCI model that is an intermediary between rodent and human SCI may be a valuable translational research resource for pre-clinically evaluating novel therapies, prior to embarking upon lengthy and expensive clinical trials. Here, we describe the development of such a large animal model. A thoracic spinal cord injury at T10/11 was induced in Yucatan miniature pigs (20-25 kg) using a weight drop device. Varying degrees of injury severity were induced by altering the height of the weight drop (5, 10, 20, 30, 40, and 50 cm). Behavioral recovery over 12 weeks was measured using a newly developed Porcine Thoracic Injury Behavior Scale (PTIBS). This scale distinguished locomotor recovery among animals of different injury severities, with strong intra-observer and inter-observer reliability. Histological analysis of the spinal cords 12 weeks post-injury revealed that animals with the more biomechanically severe injuries had less spared white matter and gray matter and less neurofilament immunoreactivity. Additionally, the PTIBS scores correlated strongly with the extent of tissue sparing through the epicenter of injury. This large animal model of SCI may represent a useful intermediary in the testing of novel pharmacological treatments and cell transplantation strategies.

A porcine model of spinal cord injury (SCI) was used to evaluate the neuroprotective effects of magnesium chloride (MgCl2) within a polyethylene glycol (PEG) formulation, called "AC105" (Acorda Therapeutics Inc., Ardsley, NY). Specifically, we tested the hypothesis that AC105 would lead to greater tissue sparing at the injury site and improved behavioral outcome when delivered in a clinically realistic time window post-injury. Four hours after contusion/compression injury, Yucatan minipigs were randomized to receive a 30-min intravenous infusion of AC105, magnesium sulfate (MgSO4), or saline. Animals received 4 additional infusions of the same dose at 6-h intervals. Behavioral recovery was tested for 12 weeks using two-dimensional (2D) kinematics during weight-supported treadmill walking and the Porcine Injury Behavior Scale (PTIBS), a 10-point locomotion scale. Spinal cords were evaluated ex vivo by diffusion-weighted magnetic resonance imaging (MRI) and subjected to histological analysis. Treatment with AC105 or MgSO4 did not result in improvements in locomotor recovery on the PTIBS or in 2D kinematics on weight-supported treadmill walking. Diffusion weighted imaging (DWI) showed severe loss of tissue integrity at the impact site, with decreased fractional anisotropy and increased mean diffusivity; this was not improved with AC105 or MgSO4 treatment. Histological analysis revealed no significant increase in gray or white matter sparing with AC105 or MgSO4 treatment. Finally, AC105 did not result in higher Mg2+ levels in CSF than with the use of standard MgSO4. In summary, when testing AC105 in a porcine model of SCI, we were unable to reproduce the promising therapeutic benefits observed previously in less-severe rodent models of SCI.

Minocycline, a commonly prescribed tetracycline antibiotic, has shown promise as a potential therapeutic agent in animal models of numerous neurologic disorders such as amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Huntington's disease, stroke, and spinal cord injury (SCI). Simvastatin is one of many hydroxymethylglutaryl-coenzyme-A reductase inhibitors prescribed to lower cholesterol. These drugs are also known to reduce inflammation and oxidative stress, improve endothelial function, and modulate the immune system in stroke, traumatic brain injury, and SCI. As both drugs have translational potential, we evaluated their neuroprotective properties here in a clinically relevant model of contusive cervical spinal cord injury. Sprague-Dawley rats underwent a unilateral cervical contusion SCI at C5 and were randomized to receive: 1. Minocycline 90 mg/kg x 3 days, 2. Simvastatin 20 mg/kg x 7 days, 3. Simvastatin 20 mg/kg x 7 days then 5mg/kg x 35 days, or 4. Saline (Control). Behavioral recovery was assessed over 6 weeks using the horizontal ladder test, cylinder rearing test, modified Montoya staircase test and grooming test. Forepaw sensitivity was also assessed using the electronic von Frey Aesthesiometer. The corticospinal and rubrospinal tracts were traced and the spinal cords were harvested 7 weeks after injury. The extent of gray matter and white matter sparing and corticospinal and rubrospinal tract sprouting were evaluated in cross sections of the spinal cord. In the end, neither minocycline nor simvastatin treatment was associated with improved performance on the behavioral tests, as compared to saline controls. Performance on the horizontal ladder test, cylinder rearing test, and von Frey sensory test were similar among all groups. Animals treated for 42 days with simvastatin scored significantly higher in the grooming score compared to other groups, but retrieved significantly fewer pellets on the modified Montoya staircase test than control and minocycline treated animals. Histologically, there were no significant differences in white and gray matter sparing and in the extent of corticospinal and rubrospinal sprouting between the four groups. In conclusion, both minocycline and simvastatin failed to improve functional and histological recovery in our model of contusive cervical spinal cord injury.

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of spinal cord injury (SCI) in which the thoracic spinal cord is injured. Additionally, because most human cord injuries occur as the result of blunt, non-penetrating trauma (e.g. motor vehicle accident, sporting injury) where the spinal cord is violently struck by displaced bone or soft tissues, the majority of SCI researchers are of the opinion that the most clinically relevant injury models are those in which the spinal cord is rapidly contused.(1) Therefore, an important step in the preclinical evaluation of novel treatments on their way to human translation is an assessment of their efficacy in a model of contusion SCI within the cervical spinal cord. Here, we describe the technical aspects and resultant anatomical and behavioral outcomes of an unilateral contusive model of cervical SCI that employs the Infinite Horizon spinal cord injury impactor. Sprague Dawley rats underwent a left-sided unilateral laminectomy at C5. To optimize the reproducibility of the biomechanical, functional, and histological outcomes of the injury model, we contused the spinal cords using an impact force of 150 kdyn, an impact trajectory of 22.5° (animals rotated at 22.5°), and an impact location off of midline of 1.4 mm. Functional recovery was assessed using the cylinder rearing test, horizontal ladder test, grooming test and modified Montoya's staircase test for up to 6 weeks, after which the spinal cords were evaluated histologically for white and grey matter sparing. The injury model presented here imparts consistent and reproducible biomechanical forces to the spinal cord, an important feature of any experimental SCI model. This results in discrete histological damage to the lateral half of the spinal cord which is largely contained to the ipsilateral side of injury. The injury is well tolerated by the animals, but does result in functional deficits of the forelimb that are significant and sustained in the weeks following injury. The cervical unilateral injury model presented here may be a resource to researchers who wish to evaluate potentially promising therapies prior to human translation.