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Background context The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016. PURPOSE The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition. Study design This is a guideline summary review. Methods This guideline is the product of the Low Back Pain Work Group of NASS’ Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors. Results Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature. Conclusions The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx

BACKGROUND Thoracolumbar pathology can result in compression of neural elements, instability, and deformity. Circumferential decompression with anterior column reconstruction is often required to restore biomechanical stability and minimize the risk of implant failure. OBJECTIVE To assess the safety and viability of wide-footprint rectangular cages for vertebral column resection (VCR). METHODS We performed VCR with wide-footprint rectangular endplate cages, which were designed for transthoracic or retroperitoneal approaches. We present our technique using a single-stage posterior approach. RESULTS A total of 45 patients underwent VCR with rectangular endplate cages. Mean age was 58 yr. Diagnoses included 23 tumors (51%), 14 infections (31%), and 8 deformities (18%). VCRs were performed in 10 upper thoracic, 17 middle thoracic, 14 lower thoracic, and 4 lumbar levels. Twenty-four cases involved a single level VCR (53%) with 18 two-level (40%) and 3 three-level (7%) VCRs. Average procedure duration was 264 min with mean estimated blood loss of 1900 ml. Neurological outcomes were stable in 27 cases (60%), improved in 16 (36%), and worse in 2 (4%). There were 7 medical and 7 surgical complications in 11 patients. There were significant decreases in postoperative thoracic kyphosis (47° vs 35°, P = .022) and regional kyphosis (34° vs 10°, P

Copyright © 2018 by the American Society of Plastic Surgeons. Background: Soft-tissue complications often dictate the success of limb salvage and the overall outcome of open fractures. Based on prior work at the R Adams Cowley Shock Trauma Center, the authors hypothesize that wounds larger than 200 cm2 are associated with a greater likelihood of both flap-related reoperation and wound complications among patients requiring soft-tissue reconstruction with a rotational flap or free tissue transfer. Methods: This study was a secondary analysis of Fluid Lavage in Open Wounds trial data that included all patients who received a rotational or free tissue flap transfer for an open fracture. The primary outcome was flap-related reoperation within 12 months of injury. The secondary outcome was wound complication, which included events treated operatively or nonoperatively. Multivariable logistic regression was used to assess the association between wound size and outcomes, adjusting for confounders. Results: Seventeen percent of the 112 patients required a flap-related reoperation. A wound size greater than 200 cm2 was not associated with reoperation in an unadjusted model (p = 0.64) or adjusting for Gustilo type (p = 0.70). The sample had an overall wound complication rate of 47.3 percent. Patients with a wound size of greater than 200 cm2 were three times more likely to experience wound complications (OR, 3.05; 95 percent CI, 1.08 to 8.62; p = 0.04) when adjusting for moderate to severe wound contamination and wound closure in the operating room. Conclusion: The findings of this study demonstrate that wound surface area is an integral determinant for wound complication following soft-tissue flap treatment, but found no association between wound surface area and flap-related reoperation rates.

Minimally invasive lateral approaches to the lumbar spine allow for interbody fusion with good visualization of the disk space, minimal blood loss, and decreased length of stay. Major neurologic, vascular, and visceral complications are rare with this approach; however, the steps in management for severe vascular injuries are not well defined. We present a case report of aortic injury during lateral interbody fusion and discuss the use of endovascular repair. This study is a case report of an intraoperative aortic injury. A 59-year-old male with ankylosing spondylitis suffered an acute L1 Chance fracture after mechanical fall. He was taken to the operating room for a T10–L4 posterior instrumented fusion followed by a minimally invasive L1–L2 lateral interbody fusion for anterior column support. During the discectomy, brisk arterial bleeding was encountered due to an aortic injury. The vascular surgery team expanded the incision in an attempt to control the bleeding but with limited success. The patient underwent intraoperative angiogram with placement of stent grafts at the level of the injury followed by completion of the interbody fusion. Despite the potentially catastrophic nature of this injury, the patient made a good recovery and was discharged home in stable condition with no new neurologic deficits. This case highlights the importance of immediate recognition and imaging of any potential vascular injury during minimally invasive lateral interbody fusion. Given the poor outcomes associated with attempted open repair, endovascular techniques provide a valuable tool for the treatment of these complex injuries with significantly less morbidity.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

Study design In vitro cadaver biomechanics study. Objective The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. Summary of background data Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. Methods Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. Results Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. Conclusions Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

Aims We compared the accuracy, operating time and radiation exposure of the introduction of iliosacral screws using O-arm/Stealth Navigation and standard fluoroscopy. Materials and Methods Iliosacral screws were introduced percutaneously into the first sacral body (S1) of ten human cadavers, four men and six women. The mean age was 77 years (58 to 85). Screws were introduced using a standard technique into the left side of S1 using C-Arm fluoroscopy and then into the right side using O-Arm/Stealth Navigation. The radiation was measured on the surgeon by dosimeters placed under a lead thyroid shield and apron, on a finger, a hat and on the cadavers. Results There were no neuroforaminal breaches in either group. The set-up time for the O-Arm was significantly longer than for the C-Arm, while total time for placement of the screws was significantly shorter for the O-Arm than for the C-Arm (p = 0.001). The mean absorbed radiation dose during fluoroscopy was 1063 mRad (432.5 mRad to 4150 mRad). No radiation was detected on the surgeon during fluoroscopy, or when he left the room during the use of the O-Arm. The mean radiation detected on the cadavers was significantly higher in the O-Arm group (2710 mRem standard deviation (sd) 1922) than during fluoroscopy (11.9 mRem sd 14.8) (p < 0.01). Conclusion O-Arm/Stealth Navigation allows for faster percutaneous placement of iliosacral screws in a radiation-free environment for surgeons, albeit with the same accuracy and significantly more radiation exposure to cadavers, when compared with standard fluoroscopy. Take home message: Placement of iliosacral screws with O-Arm/Stealth Navigation can be performed safely and effectively. Cite this article: Bone Joint J 2016;98-B:696–702.

STUDY DESIGN Case series. OBJECTIVE To evaluate radiographic and clinical outcomes of adults with spinal deformity treated with multilevel anterior column releases (ACR). SUMMARY OF BACKGROUND DATA Pedicle subtraction osteotomy can be used effectively to correct spinal deformity; however, it is not without complications. ACR is an attractive alternative minimally invasive technique for spinal deformity correction, although few clinical reports on its clinical effectiveness exist. METHODS Adults with spinal deformity who underwent multilevel ACRs (≥2) followed by open posterior instrumentation with a minimum 1-year follow-up were retrospectively reviewed. Deformity radiographic data and clinical outcomes, including the Oswestry Disability Index (ODI) and the EuroQol-5D were analyzed. RESULTS Eight patients [7 female, 1 male; mean age 65 y (49-79 y)] met inclusion criteria. The mean follow-up was 18.4 months (12-28 mo). The average number of levels treated with an ACR per patient was 2.4 (2-3). There were no anterior approach-related complications. The average number of levels instrumented posteriorly was 8.1 (3-15). Six patients underwent Schwab type 1 posterior osteotomies (partial facetectomies). After the first anterior stage, there was a significant increase in the lumbar lordosis and significant decreases in the sagittal vertical axis, pelvic tilt, and lumbopelvic mismatch (P

OBJECT The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures. METHODS Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up. RESULTS Twelve patients (7 men, 5 women, average age 42 years, range 22–68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5–8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16–68 months), and average radiographic follow-up was 37 months (range 6–68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0–52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery. CONCLUSIONS Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Revision surgery for pseudarthrosis after a lumbar spinal fusion has unpredictable functional results.The aim of this study was to determine the clinical outcomes of revision surgery to fuse the pseudarthrosis site based on the two most common diagnoses (degenerative disc disease [DDD] vs. spondylolisthesis).Patients who had a revision surgery between 1995 and 2004 for lumbar pseudarthrosis after short segment lumbar spinal fusion were identified through the institution's Spine Center surgery database. A retrospective chart review of clinical, hospital, and anesthesia records was then performed.Sixty-six patients were included in the study (28 patients with DDD and 38 patients with spondylolisthesis). Inclusion criteria were a surgical diagnosis of pseudarthrosis with a prior fusion of one or two motion segments, minimum 24 months of follow-up, and a diagnosis of either symptomatic DDD or spondylolisthesis as the primary indication for the index fusion surgery.The Oswestry disability index (ODI) and a self-assessment questionnaire were used to evaluate clinical outcomes.A retrospective chart and radiographic review was performed. Statistical analysis was done using Student t test for ODI scores and chi-square test for discrete variables from the outcome questionnaires.Follow-up radiographs were available for 64 patients (97%), and a fusion rate of 100% was found in both groups for the radiographs examined. The mean postoperative ODI score was 53.3 (30-84.4) for DDD patients and 37.2 (2.5-76) for the spondylolisthesis group (p.01). Only 50% of the patients in the DDD group felt that their overall well-being had improved since the surgery. In the spondylolisthesis group, 64% of patients stated that their overall well-being had improved since their revision surgery.The clinical outcomes after revision surgery for pseudarthrosis are worse in patients with DDD compared with spondylolisthesis despite successful repair of nonunion. Risks and benefits should be well discussed with the patients before deciding on surgical treatment for the management of pseudarthrosis, especially in patients with previous short-segment fusions done for DDD.

Study design A cross-sectional study. Objective To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area. Summary of background data The prevalence of OPLL and ONL is unknown in the non-Asian population. Methods This computed tomography-based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups. Results Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7-2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7-2.3), 4.8% in Asian Americans (95% CI: 2.8-8.1), 1.9% in Hispanic Americans (95% CI: 0.9-4.0), 2.1% in African Americans (95% CI: 0.9-4.8), and 3.2% in Native Americans (95% CI: 0.8-12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0-12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8-9.3), 26.4% in Asian Americans (95% CI: 21.9-31.5), 7.4% in Hispanic Americans (95% CI: 5.2-10.5), 2.5% in African Americans (95% CI: 1.2-4.9), and 25.8% in Native Americans (95% CI: 16.5-37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001). Conclusion This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans. Level of evidence 3.

Background context Cervical spine clearance protocols were developed to standardize the clearance of the cervical spine after blunt trauma and prevent secondary neurologic injuries. The degree of incorporation of evidence-based guidelines into protocols at trauma centers in California is unknown. Purpose To evaluate the cervical spine clearance protocols in all trauma centers of California. Study design An observational cross-sectional study. Patient sample Included from Level I, II, III trauma centers in California. Outcome measures The self-reported outcomes of each trauma center's cervical spine clearance protocols were assessed. Methods Level I (n=15), II (n=30), and III (n=11) trauma centers in California were contacted. Each available protocol was reviewed for four scenarios: clearing the asymptomatic patient, the initial imaging modality used in patients not amenable to clinical clearance, and the management strategies for patients with persistent neck pain with a negative computed tomography (CT) scan and those who are obtunded. Results were compared with the 2009 Eastern Association for the Surgery of Trauma (EAST) cervical spine clearance guidelines. Results The response rate was 96%. Sixty-three percent of California's trauma centers (Level I, 93%; Level II, 60%; Level III, 27%) had written cervical spine clearance protocols. For asymptomatic patients, 83% of Level I and 61% of Level II centers used National Emergency X-Radiography Utilization Study criteria with/without painless range of motion. For those requiring imaging, 67% of Level I and 56% of Level II centers stated a CT scan should be the first line of imaging. For obtunded patients and patients with persistent neck pain and a negative CT scan, more than 90% of Level I and more than 70% of Level II trauma centers incorporated the 2009 EAST recommendations. No institution recommended passive flexion-extension radiographs for the obtunded patient. Conclusions Written cervical spine clearance protocols exist in 63% of California's trauma centers and only 51% of the centers have protocols that follow current evidence-based guidelines. Standardization and utilization of these protocols should be encouraged to prevent missed injuries and secondary neurologic injuries.

Background Internal fixation of OTA type 31-A2 proximal femoral fractures can be performed with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN). Controversy exists as to which is the best implant for these types of fractures. The primary aim of this study was to investigate the stability of 31-A2 fractures as a function of loss of medial cortical buttress. The secondary aim was to assess the influence of fracture stability on the different internal fixation constructs. Methods Simulated simple intertrochanteric fractures were made in 12 cadaver proximal femurs. Six fractures were fixed with an SHS-P and 6 with an SHS-IMN. Both implants were instrumented with a strain gauge at the lag screw-nail/plate interface to allow assessment of implant load bearing (ILB). A primary fracture line, in accordance with the 31-A2 OTA classification, was created after which 3 subsequent horizontal osteotomies in 1-cm increments were made across the medial cortex. Compressive loading up to 1050 N was performed after each osteotomy. Results ILB was presented as percentage of maximal ILB. SHS-P constructs increased their load bearing gradually. For SHS-P constructs, ILB was 8.1% ± 1.8% in the intact state, increasing to 49.6% ± 14.0% after the initial intertrochanteric osteotomy (P = 0.0002), 68.7% ± 15.9% after the first medial osteotomy (P = 0.028), and 80.0% ± 15.9% after the second medial osteotomy (P = 0.15). After the first-level medial osteotomy, SHS-IMN constructs reached a plateau in which the implant carried the entire load. Conclusions Type 31-A2 fractures become increasingly unstable with increased medial comminution (or fragment size). SHS-P constructs were more load sharing than SHS-IMN constructs. These findings may help guide the surgeon in choice of implant for a 31-A2 intertrochanteric fracture, leaning toward SHS-IMN for the more unstable fracture patterns.

The new-generation multidetector computed tomographic (CT) scanners allow for the generation of virtual x-rays from the data acquired during the evaluation of pelvic fractures. Special software allows technicians to obtain the appropriate orientation required for adequate inlet and outlet views, which would eliminate repeat trips to the radiography suite to acquire adequate x-rays. The purpose of this study is to compare the quality virtual x-rays and conventional x-rays that are used in evaluating pelvis fractures.A retrospective database review was performed to identify patients who were operated on with a diagnosis of pelvis fracture. The inclusion criteria were AO/OTA type B or C pelvic fractures, age older than 18 years, complete set of anteroposterior (AP) pelvis, inlet, and outlet x-rays and a multidetector pelvis CT scan. Virtual AP pelvis, inlet, and outlet views were generated from the CT scan data. Two fellowship-trained orthopedic trauma surgeons reviewed the virtual and conventional studies separately in association with CT scans and graded the quality of the studies on a custom developed questionnaire.Twenty patients were eligible for the study. The AP pelvis image quality was similar for both conventional and virtual images except for the rotation of the pelvis, which was improved in the virtual images. The inlet and outlet image quality was better in all domains in the virtual x-ray group when compared with the conventional x-rays. The percentage of adequate inlet and outlet images was higher in the virtual x-ray group when compared with the conventional x-ray group.The results show that the virtual inlet and outlet images consistently provided higher rates of adequate x-rays when compared with the conventional x-rays. In the evaluation of patients with pelvis fractures, the use of the virtual inlet and outlet views instead of the conventional x-rays may provide some advantages, such as decreased radiation exposure to the patient, reduced overall cost, and reduced repeat x-rays to achieve adequate views.Diagnostic study, level V.

The objective of this project was to evaluate magnetic resonance imaging (MRI) issues at 3 T for an armor-piercing bullet and to determine if this item could be identified using a ferromagnetic detection system. An armor-piercing bullet (.30 caliber, 7.62 × 39, copper-jacketed round, steel core; Norinco) underwent evaluation for magnetic field interactions, heating, and artifacts using standardized techniques. Heating was assessed with the bullet in a gelled-saline-filled phantom with MRI performed using a transmit/receive radio frequency body coil at a whole-body-averaged specific absorption rate of 2.9 W/kg for 15 minutes. Artifacts were characterized using T1-weighted spin echo and gradient echo pulse sequences. In addition, a special ferromagnetic detection system (Ferroguard Screener; Metrasens, Lisle, Illinois) was used in an attempt to identify this armor-piercing bullet. The findings indicated that the armor-piercing bullet showed substantial magnetic field interactions. Heating was not excessive. Artifacts were large and may create diagnostic problems if the area of interest is close to this bullet. The ferromagnetic detection system yielded a positive result. We concluded that this armor-piercing bullet is MR unsafe. Importantly, this ballistic item was identified using the particular ferromagnetic detection system utilized in this investigation, which has important implications for MRI screening and patient safety.

OBJECTIVES The goal of this study is to compare the fatigue strength of a locking intramedullary nail (LN) construct with a double locking plate (DLP) construct in comminuted proximal extra-articular tibia fractures. METHODS Eight pairs of fresh frozen cadaveric tibias with low bone mineral density [age: 80 ± 7 (SD) years, T-score: -2.3 ± 1.2] were used. One tibia from each pair was fixed with LN, whereas the contralateral side was fixed with DLP for complex extra-articular multifragmentary metaphyseal fractures (simulating OTA 41-A3.3). Specimens were cyclically loaded under compression simulating single-leg stance by staircase method out to 260,000 cycles. Every 2500 cycles, localized gap displacements were measured with a 3D motion tracking system, and x-ray images of the proximal tibia were acquired. To allow for mechanical settling, initial metrics were calculated at 2500 cycles. The 2 groups were compared regarding initial construct stiffness, initial medial and lateral gap displacements, stiffness at 30,000 cycles, medial and lateral gap displacements at 30,000 cycles, failure load, number of cycles to failure, and failure mode. Failure metrics were reported for initial and catastrophic failures. RESULTS DLP constructs exhibited higher initial stiffness and stiffness at 30,000 cycles compared with LN constructs (P < 0.03). There were no significant differences between groups for loads at failure or cycles to failure. CONCLUSIONS For the fixation of extra-articular proximal tibia fractures, a LN provides a similar fatigue performance to double locked plates. The locked nail could be safely used for fixation of proximal tibia fractures with the advantage of limited extramedullary soft tissue damage.

Surgical management for lumbar stenosis is generally safe and provides significant improvements in pain, disability, and function. Successful lumbar decompression hinges on removing an appropriate amount of lamina and other compressive pathology in the lateral recess. Too little bony decompression can result in persistent pain and disability, while over resection of the pars and/or facets may jeopardize spinal stability. In this unique report, we present for the first time an acute iatrogenic grade 4 L5–S1 spondylolisthesis distal to a L3–5 laminectomy and circumferential instrumented fusion due to bilateral iatrogenic L5 pars fractures and its management and clinical outcomes after revision operation. The patient presented with worsening pain, neurologic compromise, and severe sagittal imbalance. The iatrogenic, high-grade spondylolisthesis was urgently addressed with a L5–S1 anterior lumbar interbody fusion and extension of posterior instrumentation to the pelvis, which resulted in considerable pain relief, resolution of neurologic deficits, and reconstitution of acceptable sagittal imbalance. All attempts during a lumbar decompression should be made to prevent iatrogenic pars fractures, as they may result in severe sagittal imbalance, neurologic compromise, and persistent disability. Iatrogenic, high-grade L5–S1 spondylolisthesis can be successfully treated with reduction using circumferential fusion of the lumbosacral junction.

STUDY DESIGN Retrospective cohort analysis. OBJECTIVE To evaluate the economic impact of revision surgery for proximal junctional failures (PJF) after thoracolumbar fusions for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA PJF after fusions for ASD is a major cause of disability. Although clinical sequelae are described, PJF-revision operation costs are incompletely defined. METHODS Consecutive adults who underwent thoracolumbar fusions for ASD (August, 2003 to January, 2013) were evaluated. Inclusion criteria include construct from pelvis to L2 or above and minimum 6 months follow-up after the index ASD operation. Direct costs (surgical supplies/implants, room/care, pharmacy, services) were identified from medical billing data and calculated for index ASD operations and subsequent surgeries for PJF. Not included in direct cost data were indirect costs, charges, surgeon fees, or revision operations for indications other than PJF (i.e., pseudarthrosis). Patients were compared based on the construct's upper-instrumented vertebra: upper thoracic (UT: T1-6) versus thoracolumbar junction (TLjxn: T9-L2). RESULTS Of 501 patients, 382 met inclusion criteria. Fifty-one patients [UT:14; TLjxn: 40 at index; average follow-up 32.6 months (6-92 months)] had revisions for PJF, which summed to $3.2 million total direct cost. Average direct cost of index operations for the cohort ($68,294) was significantly greater than PJF-revisions ($55,547). Compared with TLjxn, UT had a significantly higher average cost for index operations ($79,860 vs. $65,868). However, PJF-revision cases were similar in average cost (UT:$60,103; TLjxn:$53,920; P = 0.09). Costs of PJF amounted to an additional 12.1% of the total index surgical cost in 382 patients. CONCLUSION Revision operations for PJF after long thoracolumbar fusions for ASD are associated with an average direct cost of $55,547 per case. Revision costs for PJF are similar based on the index procedure's upper-instrumented vertebra level. At a major tertiary center over a 10-year period, PJF came at a very significant economic expense amounting to $3.2 million for 57 cases. LEVEL OF EVIDENCE 3.

Introduction Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods Twelve specimens received bilateral T12–S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2–L3 and L3–L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2–L4) and entire fixation site (T12–S1) was measured. All specimens were then fatigue tested for 35K cycles. Results Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2–L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant ( p = 0.095), was 22.2% greater in the PSO + XLIF group than in the PSO-only group. Conclusions Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this.

Object Expandable cages are becoming more popular due in large part to their versatility, but subsidence and catastrophic failure remain a concern. One of the proposed reasons of failure is edge loading of the endplate caused by a mismatch between the sagittal alignment of the motion segment and cage. This in vitro analysis investigates the endplate forces characteristic of expandable and fixed interbody cages in a single-level human cadaver corpectomy model. Methods Ten human thoracolumbar spines (T10–L2, L3–5) were biomechanically evaluated following a single-level corpectomy that was reconstructed with an expandable or fixed cage. Fixed cages were deployed with the best-fitting end cap combination, whereas expandable cages were deployed in normal, hypolordotic, and hyperlordotic alignment scenarios. The endplate forces and contact area were measured with a pressure measurement system, and the expansion torque applied by the surgeon was measured with a custom-made insertion device. Results The contact areas of the expandable cages were, in general, higher than those of the fixed cages. The endplate forces of the expandable cages were similar to those of the fixed cages in the normal alignment scenario. Higher endplate forces were observed in the hyperlordotic scenario, whereas the endplate forces in the hypolordotic and normal alignment scenarios were similar. There was no correlation with the expansion torque and the final endplate forces. Conclusions Expandable cages resulted in consistently higher contact area and endplate forces when compared with the fixed cages. Because the expansion torque does not correlate with the final endplate forces, surgeons should not rely solely on tactile feedback during deployment of these cages.

End-stage haemophiliac arthropathy can be successfully treated with total knee arthroplasty. However, the functional results may not be as good as anticipated and certain pre-op knee characteristics may alter the functional results. The purpose of this study was to evaluate the functional outcome of TKA in haemophilic patients with specific attention to final range of motion and residual flexion contracture of the joint. Twenty-one consecutive patients were retrospectively reviewed. The average age was 34 years with an average follow-up of 5.7 years. Functional status was evaluated with Hospital for Special Surgery Knee Score. Receiving Operating Characteristics analysis was used to determine the threshold of pre-operative flexion contracture degree to avoid residual knee contracture. The range of motion was increased in 16 joints and unchanged in three joints and decreased in the remaining two. Preoperative average range of motion was 37.6°, improved to 57.1° post-operatively. The average knee score increased from 27.85 (15-30) points pre-operatively to 79.42 (12-94) points at the last follow-up. The degree of pre-operative flexion contracture was found to be a good predictor for residual flexion contracture. (Specificity: 85.7%, sensitivity: 100%, cut-off: 27.5°). Total knee replacement improves the quality of life in patients with advanced haemophilic arthropathy. Statistical analysis revealed that pre-op flexion contracture of 27.5° is an important threshold. Patients should be operated before that stage to gain maximum benefit with minimal gait abnormalities.

Object Ankylosing spondylitis (AS) is a genetic condition that frequently results in spinal sagittal plane deformity of thoracolumbar or cervicothoracic junctions. Generally, a combination of osteotomy and spinal fixation is used to treat severe cases. Although surgical techniques for traumatic injury across the cervicothoracic junction have been well characterized in clinical and biomechanical literature, the specific model of instrumented opening wedge osteotomy in autofused AS has not been studied biomechanically. This study characterizes the structural stability of various posterior fixation techniques across the cervicothoracic junction in spines with AS, specifically considering the effects of posterior rod diameter and material type. Methods For each of 10 fresh-frozen human spines (3 male, 7 female; mean age 60 ± 10 years; C3–T6), an opening wedge osteotomy was performed at C7–T1. Lateral mass screws were inserted bilaterally from C-4 to C-6 and pedicle screws from T-1 to T-3. For each specimen, 3.2-mm titanium (Ti), 3.5-mm Ti, and 3.5-mm cobalt chromium (CoCr) posterior spinal fusion rods were tested. To simulate the anterior autofusion and long lever arms characteristic of AS, anterior cervical plates were placed from C-4 to C-7 and T-1 to T-3 using fixed angle screws. Nondestructive flexion-extension, lateral bending, and axial rotation tests were conducted to 3.0 Nm in each anatomical direction; 3D motion tracking was used to monitor primary range of motion across the osteotomy (C7–T1). Biomechanical tests used a repeat-measures test design. The order of testing for each rod type was randomized across specimens. Results Constructs instrumented with 3.5-mm Ti and 3.5-mm CoCr rods were significantly stiffer in flexion-extension than those with the 3.2-mm Ti rod (25.2% ± 16.4% and 48.1% ± 15.3% greater than 3.2-mm Ti, respectively, p < 0.05). For axial rotation, the 3.5-mm Ti and 3.5-mm CoCr constructs also exhibited a significant increase in rigidity compared with the 3.2-mm Ti construct (36.1% ± 12.2% and 52.0% ± 20.0%, respectively, p < 0.05). There were no significant differences in rigidity seen between the 3 types of rods in lateral bending (p > 0.05). The 3.5-mm CoCr rod constructs showed significantly higher rigidity in flexion-extension than the 3.5-mm Ti rod constructs (33.1% ± 15.5%, p < 0.05). There was a trend for 3.5-mm CoCr to have greater rigidity in axial rotation (36.2% ± 18.6%), but this difference was not statistically significant (p > 0.05). Conclusions The results of this study suggest that 3.5-mm CoCr rods are optimal for achieving the most rigid construct in opening wedge osteotomy in the cervicothoracic region of an AS model. Rod diameter and material properties should be considered in construct strategy. Some surgeons have advocated anterior plating in patients with AS after osteotomy for additional stability and bone graft surface. Although this effect was not examined in this study, additional posterior stability achieved with CoCr may decrease the need for additional anterior procedures.

The management of massive pelvic osteolysis can pose a substantial challenge when a revision total hip arthroplasty is performed. For patients with well-fixed, well-positioned acetabular components and with contained osteolytic defects, retention of the prosthesis with bone-grafting of the osteolytic lesions is an accepted surgical strategy1-4. In contrast, in the setting of massive osteolysis with pelvic discontinuity, the acetabular component is usually loose and must be revised. To our knowledge, the uncommon clinical scenario in which pelvic discontinuity and massive osteolysis are associated with a well-fixed acetabular component has not been discussed in the literature. In the following case report, we describe the surgical treatment and clinical results of a patient with this challenging combination of problems. The patient was managed with acetabular component retention, open reduction and internal fixation of the discontinuity, and morselized bone-grafting of the osteolytic bone defects. The patient was informed that data concerning the case would be submitted for publication, and she consented. A sixty-one-year-old woman presented to us with right-sided groin pain nine years after a right primary total hip arthroplasty. The postoperative course had been uncomplicated, and she had remained asymptomatic until eight months prior to the time of presentation. She had no history of trauma. The pain was worse with activity and improved with rest. She had no fever or other constitutional symptoms. The medical history was notable for obesity, coronary artery disease that required coronary artery bypass grafting six months prior to presentation, and a previous episode of diverticulitis, which required a partial colectomy to manage acute intestinal obstruction. She also had a history of cholecystectomy, multiple hernia repairs, and left hip and right knee replacements. She was retired, divorced, and living alone. The cardiovascular disease limited her to walking inside her home. On physical examination, she …

PubMedID: 19564754 STUDY DESIGN.: Experimental study. OBJECTIVE.: To investigate whether anterior spine fusion in the immature porcine spine has an adverse effect on the development of spinal canal. SUMMARY OF BACKGROUND DATA.: Neurocentral cartilage (NCC) is located in the posterior vertebral body and responsible for the development of posterior aspect of the spinal canal. Injury to the NCC interferes with the development of the spinal canal. METHODS.: Twelve 8-week-old domestic pigs were used to develop an anterior fusion model. A standard procedure as L3-L4, L4-L5 discectomy, and L3-L5 anterior instrumented spine fusion was performed. To evaluate the development of the spinal canal, all subjects had computed tomography scans before the procedure and at the final follow-up. The spinal canal area was measured at the control level (CL) (L2), arthrodesis level (AL) (L4), superior (L3), and inferior (L5) instrumented level (SIL and IIL). Percent change in spinal canal area from before surgery to final follow-up was also calculated. RESULTS.: Eleven subjects were available for the study. All subjects developed local kyphosis over the fused segments. The average area of L2 (CL) was 0.56 ± 0.06 cm before surgery. The average areas of the L3 (SIL), L4 (AL), and L5 (IIL) were 0.62, 0.70, and 0.77 cm, respectively. At the final follow-up the average area of L2 was 1.20 cm. The average areas of the SIL, AL, and IIL were 1.16, 1.19, and 1.33 cm, respectively. The percent increase in spinal canal area at the CL was 116.6% whereas it was 85.8%, 71.0%, and 71.2% at SIL, AL, and IIL, respectively. CONCLUSION.: Anterior spinal arthrodesis in the immature porcine spine results in iatrogenic retardation on spinal canal growth. This effect is most likely related to the tethering effect of the interbody fusion over the NCC. Although, it is difficult to directly extrapolate these findings to clinical practice, the spine surgeons operating on pediatric patients should be aware of this possibility. © 2009 Lippincott Williams & Wilkins, Inc.

The Salter innominate osteotomy has been used successfully for many years in the treatment of developmental dysplasia of the hip. One of its main drawbacks is the need for internal fixation with pins and their subsequent removal. We describe a modification of this osteotomy that does not require pin fixation and secondary removal. We retrospectively reviewed 114 hips in 94 patients who had been operated on by a single surgeon. An oblique rather than the original horizontal osteotomy was used without internal fixation. There were 80 female and 14 male patients. The mean age at operation was 25 months (18 to 84) and the mean follow-up was 30 months (12 to 88). Most patients required additional open reduction and capsuloplasty. The mean pre-operative acetabular index was 37.9 degrees (24 degrees to 54 degrees ), which decreased to 19.9 degrees (7 degrees to 29 degrees ) in the immediate post-operative period, and improved to 14.6 degrees (5 degrees to 25 degrees ) at the final follow-up (student's t-test, p < 0.0001). We believe that by changing the direction of the osteotomy line, it is possible to avoid pin fixation. The radiological outcomes are comparable to those of the original technique, but longer follow-up will be necessary.

Biomechanical.Evaluate spinal stability achieved with different levels of posterior percutaneous fixation (postPerc) for thoracolumbar fractures in cadavers subjected to ICU activities."Spine damage control" involves postPerc performed within 24 hours of injury and staged, elective, definitive stabilization. Amount of instrumentation needed to initially achieve adequate spinal stability, minimize morbidity, and accommodate ICU care needs between stages are not defined.In full-unembalmed cadavers motion-tracking sensors were placed at T11 and L1. A T12 corpectomy with PLC injury was stabilized with 1, 2, and 3 levels of PostPerc above/below the injury. Motions between T11 and L1 were measured during Log-Roll and Sit-Up on an ICU bed. After in situ testing, anatomic spinal motion ranges were determined under pure moment loads.5 cadavers were evaluated. For Log-Roll, 2 and 3 levels above/below restored stability to intact, whereas 1 level above/below did not for axial rotation. For translation, all instrumentation restored stability to intact. During Sit-Up, a linear increase in flexion was observed. At 45° Sit-Up, 2 and 3 levels above/below were similar to intact for flexion; 1 level above/below had significantly more flexion. All instrumentations restored translation to intact for Sit-Up; significantly more axial collapse occurred for instrumentation compared with intact. During ex situ testing, 2 and 3 levels above/below were similar; 1 level above/below had significantly greater laxity in flexion, extension, and axial rotation.Posterior instrumentation 2 or 3 levels above/below a severe thoracolumbar fracture model can restore spinal stability back to its intact condition. 2 levels of fixation above/below this "worst-case scenario" is minimum fixation sufficient to provide absolute spinal stability in the ICU setting as a "Damage Control" technique in patients with polytrauma. In less severe injury models, 1 level of fixation above/below may provide adequate spinal stability; although this should be confirmed in future investigations.N/A.

STUDY DESIGN Biomechanical study in an animal model. OBJECTIVE To evaluate the feasibility of sequential dilation of the immature pedicles by dilators and to determine the biomechanical stability of screws placed in these expanded pedicles. SUMMARY OF BACKGROUND DATA Pedicle screws have become the implant of choice in spinal fixation. Secondary to the small vertebra sizes of pediatric patients and difficulty in finding appropriate screw sizes, they have found limited use in pediatric spine. Dilation of the pediatric pedicles may overcome the limitation secondary to discrepancy between screw sizes. However, there are no data in the literature regarding dilation capacity of pediatric pedicles to enable larger pedicle screw fixation. METHODS Two-month-old domestic pig vertebrae were used. The right pedicles were dilated with stainless steel dilators just before there is visual evidence of pedicle failure. The left pedicles served as a control group. The inner and outer diameters of the pedicles were measured on the CT scans before and after dilation. The pedicles were instrumented with 3.5-mm pedicle screws at the thoracic level and 4.0-mm pedicle screws at the lumbar level. The pullout strength of each pedicle was measured. RESULTS The dilation procedure resulted in an increase in both inner (2.59 +/- 0.75 to 3.32 +/- 0.58 mm) and outer diameters (5.43 +/- 0.95 to 6.21 +/- 0.96 mm) (P < 0.05). The inner diameters dilated more than the outer diameters (34.3% vs. 15.0%). The pullout strength of the expanded pedicles (320.1 +/- 83.9 N) was significantly lower than the nonexpanded ones (408.1 +/- 102.0 N) (P < 0.01). CONCLUSIONS This study demonstrated that immature pedicles can be expanded by application of serial dilators. However, dilation significantly decreases the pullout strength of the pedicle.

Background: The combination of surgery and radiation therapy is a common clinical practice in the treatment of spinal tumors. Although it is known that metallic implants disturb radiation therapy beams, it is not known what kind of dose distributions appear with spinal irradiation in the presence of a spinal implant. The aim of the present study was to investigate the effect of various spinal implant constructs on the dose of radiation delivered to the spinal canal in a single-level metastasis model. Methods: We performed four spinal implant reconstructions on standard sawbones spine models: posterior instrumentation without anterior column reconstruction, posterior instrumentation with anterior column reconstruction with use of a titanium cage, anterior instrumentation with anterior column reconstruction with use of a titanium cage, and anterior instrumentation with anterior column reconstruction with use of chest tubes filled with bone cement. Irradiation with two different radiation therapy units (a cobalt-60 teletherapy unit and a linear accelerator) was performed twice for each model in a posterior-to-anterior direction, and thermoluminescent dosimeters were used to measure the dose changes in the anterior, middle, and posterior portions of the spinal canal. Results: Compared with the sawbones-only model, the posterior instrumentation reconstructions resulted in a 5% to 7% decrease in the radiation dose delivered to the spinal canal with both radiation therapy units, whereas the anterior instrumentation reconstructions resulted in a 1% decrease in the dose delivered with the linear accelerator unit and a ≤2% increase in the dose delivered with the cobalt-60 teletherapy unit. When thermoluminescent dosimeters in the middle of the spinal canal were evaluated individually, anterior instrumentation with anterior column reconstruction with use of bone cement-filled chest tubes resulted in a 5.5% increase in the radiation dose delivered with the cobalt-60 teletherapy unit, whereas all of the other instrumentation models resulted in a

Radionuclide synovectomy is a reliable therapy in patients with chronic synovitis. However, radiation doses delivered to non-target organ systems due to leakage of radioactive material from the articular cavity are an important disadvantage of this procedure. In this study we compared extraarticular leakage values of the 3 commonly used radiopharmaceuticals;90Y-citrate,90Y-silicate and186Re-sulfide colloid. Thirty-five patients with persistent synovitis were enrolled in the study. Twenty-two hemophilic, 8 rheumatoid arthritis and 5 patients with pigmented villonodular synovitis were studied.90Y labeled silicate and citrate were used for knee joints and186Re-sulfide for intermediate sized joints. Radiocolloid leakage values were evaluated using a gamma camera with 20% window centered over the bremsstrahlung photopeak of90Y and a respective window over the 137 keV photopeak of186Re. Regions of interest were drawn over the injection site, the regional lymph nodes and the background areas. Leakage of radiocolloid was calculated by dividing the counts/pixel in the regional lymph node area to the counts/pixel in the injection site. No visible leakage was observed. The median leakage values calculated for90Y-citrate,90Y-silicate and186Re-sulfide were found as 1.9%, 2.4% and 2.7%, respectively. The difference between the variability of leakage values was not statistically significant (p > 0.05).Conclusion: There was no significant difference in terms of extraarticular leakage between90Y-citrate,90Y-silicate and186Re-sulfide radiocolloids.

Retrospective series.To delineate the efficiency of using Lenke criteria during the decision of whether to include the proximal thoracic curve into instrumented fusion or not in patients with adolescent idiopathic scoliosis (AIS) treated with posterior translational instrumentation.Lenke and colleagues classified the curves of patients with AIS and assigned the term "structural" or "nonstructural" to each curve. However, there is still not much consensus on the definition of structural proximal thoracic curve, and structurality criteria for proximal thoracic curve have not been validated yet.Inclusion criteria were: (1) patients with AIS treated with a posterior translational instrumentation system and older than 10 years; (2) nonstructural upper thoracic curves (side bending Cobb25 degrees and T2-T5 kyphosis+20 degrees); and (3) a minimum of 2 years of follow-up. A total of 37 consecutive patients, including 6 males and 31 females, with AIS that was treated, with an average age of 15 years (range 11-24) and average follow-up of 55 months (range 24-90) were studied. For radiologic evaluation of the patients, preoperative, postoperative, and latest follow-up radiographs were used. There were 2 groups constructed according to the involvement of proximal thoracic curve into instrumented fusion. Group 1 included those patients who underwent uppermost extent of the instrumentation, either T2 or T3, indicating inclusion of proximal thoracic curve into instrumentation. Group 2 included individuals who underwent uppermost extent of the instrumentation at T4 or lower, indicating partial or no inclusion of the proximal thoracic curve into instrumented fusion. Radiographic evaluation included the measurement of proximal thoracic, main thoracic, and thoracolumbar-lumbar curves. On the lateral radiographs, sagittal Cobb angles of T2-T5, T5-T12, and T10-L2 were measured. Difference between right and left coracoid process heights, clavicle angle, and T1 tilt were determined for assessment of shoulder balance.The 2 groups were statistically equivalent in terms of age at surgery, follow-up time, preoperative proximal thoracic and main thoracic, and their corresponding side bending curve magnitudes, as well as the parameters related to shoulder balance before surgery (P0.05). The 2 groups were also statistically equivalent regarding immediate postoperative and latest follow-up proximal thoracic and main thoracic, and parameters related to shoulder balance (P0.05).It was observed that the Lenke description for structurality of proximal thoracic curves can effectively determine which curves need fusion and which curves do not. Because there was no difference among inclusion of a nonstructural proximal thoracic curve into fusion or solely fusing the main thoracic curve in terms of outcomes, extension of fusion to T2 or T3 is unnecessary. In this patient population, the question of what the upper extent of instrumentation should be could not be answered.

This study aimed at evaluating the additional stability that is provided by anterior external and internal fixators in an unstable pelvic fracture model (OTA 61-C). An unstable pelvic fracture (OTA 61-C) was created in 27 synthetic pelves by making a 5-mm gap through the sacral foramina (posterior injury) and an ipsilateral pubic rami fracture (anterior injury). The posterior injury was fixed with either a single iliosacral (IS) screw, a single trans-iliac, trans-sacral (TS) screw, or two iliosacral screws (S1S2). Two anterior fixation techniques were utilized: external fixation (Ex-Fix) and supra-acetabular external fixation and internal fixation (In-Fix); supra-acetabular pedicle screws connected with a single subcutaneous spinal rod. The specimens were tested using a nondestructive single-leg stance model. Peak-to-peak (P2P) displacement and rotation and conditioning displacement (CD) were calculated. The Ex-Fix group failed in 83.3 % of specimens with concomitant single-level posterior fixation (Total: 15/18–7 of 9 IS fixation, 8 of 9 TS fixation), and 0 % (0/9) of specimens with concomitant two-level (S1S2) posterior fixation. All specimens with the In-Fix survived testing except for two specimens treated with In-Fix combined with IS fixation. Trans-sacral fixation had higher pubic rotation and greater sacral and pubic displacement than S1S2 (p

We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125 000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75 800 cycles (sd 33 900) vs 12 800 cycles (sd 6100); p = 0.007) and mean axial stiffness (220 N/mm (sd 80) vs 70 N/mm (sd 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (sd 0.9) vs 5.1 Nm/° (sd 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78 900 cycles (sd 25 600) vs 52 400 cycles (sd 22 500); p = 0.04). The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients. Cite this article: Bone Joint J 2014;96-B:114–21.

STUDY DESIGN Observational, cross-sectional. OBJECTIVE To evaluate cervical spine clearance protocols in level 1 trauma centers in the United States. SUMMARY OF BACKGROUND DATA Cervical spine clearance protocols were developed to prevent missed injuries that could result in neurological deficits. The degree of incorporation of evidence-based guidelines into protocols at trauma centers in the United States is unknown. METHODS Level 1 trauma (n = 191) centers in the United States were contacted. Each available protocol was reviewed for 4 scenarios: clearing the asymptomatic patient, the imaging used in patients not amenable to clinical clearance, the management strategies for patients with persistent neck pain with a negative computed tomographic (CT) scan, and those who are obtunded. RESULTS The response rate was 87%. Cervical spine clearance protocols existed in 57% of the institutions. National Emergency X-Radiography Utilization Study criteria to clear asymptomatic patients were recommended in 89% of protocols. Sixty percent of protocols used CT scans as the first line of imaging. In patients with persistent neck pain with negative CT scan flexion-extension plain radiographs were the most common (30%) next step for clearance. In patients who are obtunded, a CT scan followed by a magnetic resonance imaging was the most common method (31%) of clearance. Eight percent of the protocols recommended dynamic flexion-extension views in patients who are obtunded, which are contraindicated. CONCLUSION Written cervical spine clearance protocols exist in 57% of level 1 trauma centers in the United States. These protocols are highly variable and standardization and utilization of these protocols should be encouraged in all trauma centers to prevent missed injuries and neurological catastrophes. LEVEL OF EVIDENCE 4.

OBJECTIVES Inlet and outlet views are essential in the evaluation of patients with pelvic injuries. The optimal angles that should be used to obtain these views are still debated. METHODS Computed tomography scans of 70 patients without pelvic ring injuries were analyzed. Using the raw data from the computed tomography images, virtual pelvic x-rays were generated. The images were rotated 1 degree at a time and a total of 360 images were generated. The same procedure was repeated to create solid 3-dimensional (3D) reconstructions. Two trauma-trained orthopaedic surgeons then reviewed all 360 images to select inlet and outlet views as described in previous literature. Intraclass correlation coefficients were calculated for each inlet and outlet value. RESULTS The average inlet angle (caudal tilt) that was required to achieve a view where the promontory overlaps the S1 body was found to be 26.7 degrees (95% confidence interval, 25-29) with virtual x-rays and 24.3 degrees (95% confidence interval, 22-26) with 3D reconstructions. The average outlet angle (cephalad tilt) that was required to achieve a view where the superior border of the pubic symphysis overlaps the S2 body was 43.7 degrees (95% confidence interval, 42-45) with virtual x-rays and 43.8 degrees (95% confidence interval, 42-45) with 3D reconstructions. There was no difference in these angles based on gender, whereas sacral dysmorphism increased the angle needed to obtain the outlet view by an average of 5 degrees. CONCLUSIONS This study demonstrated that the ideal angle to obtain inlet views should be approximately 25 degrees and to obtain outlet views should be approximately 45 degrees during screening x-rays to evaluate patients who were diagnosed with pelvic injuries. Application of these new values in the clinical practice would provide higher rates of adequate studies and further prospective clinical studies should be performed to validate these parameters.

Objectives Iliosacral fixation of unstable pelvic fractures does not produce enough stability to allow for immediate postoperative weight bearing. Triangular osteosynthesis creates additional resistance to vertical displacement and rotation. A disadvantage is the loss of the L5/S1 motion segment. We propose a modification of the standard triangular osteosynthesis construct in which the contralateral S1 pedicle is used. As the ipsilateral L5 pedicle is unavailable for fixation in a saw-bones composite pelvic model, we compared ipsilateral and contralateral S1 pedicle screw constructs. We hypothesized that ipsilateral and contralateral S1 pedicle screw constructs would demonstrate no difference in displacement or rotation. Methods Seven saw bones pelvic models were tested. A 5-mm vertical fracture gap was created through the left sacrum while the pubic symphysis was completely dissociated. Each pelvis was tested sequentially in 4 triangular osteosynthesis configurations: ipsilateral S1 screw with anterior plate, contralateral S1 screw with anterior plate, contralateral S1 screw without anterior plate, and ipsilateral S1 screw without anterior plate. Specimens were cyclically loaded from 100-200 N at 0.25 Hz for 25 cycles and then loaded up to 300 N at 10 mm/min while displacement and rotation at the sacral and pubic fracture sites were measured. Results There was no difference in any of the displacement measures between ipsilateral and contralateral constructs. When comparing rotation, the contralateral configuration experienced significantly less rotation than the ipsilateral configuration with and without the anterior plate applied. Conclusions Within the limitations of the current model, contralateral S1 constructs for modified triangular osteosynthesis were biomechanically equal to ipsilateral constructs in preventing displacement and superior in preventing rotation.

Thoracic disc herniations are associated with serious neurological consequences if not treated appropriately. Although a number of techniques have been described, there is no consensus about the best surgical approach. In this study, the authors report their experience in the operative management of patients with thoracic disc herniations using minimally invasive lateral transthoracic trans/retropleural approach. A series of 33 consecutive patients with thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through lateral approach is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed. Forty disc levels in 33 patients (18F/15M; mean age, 52.9) were treated. Twenty-three patients presented with myelopathy (69 %), 31 had radiculopathy (94 %), and 31 had axial pain (94 %). Among patients with myelopathy, 14 (42.4 %) had bladder and/or bowel dysfunction. In the last eight cases (24 %), the approach was retropleural instead of transpleural. Patients were followed up for 18.2 months on average. The mean length of hospital stay was 5 days. None of the patients developed neurological deterioration postoperatively. Among 23 patients who had myelopathy signs, 21 (91 %) had improved postoperatively. The mean preoperative visual analog scale pain score, Oswestry Disability Index score, SF-36 PCS, and mental component summary scores were 7.5, 42.4, 29.6, and 37.5 which improved to 3.5, 33.2, 35.5, and 52.6, respectively. Perioperative complications occurred in six patients (18.1 %), all of which resolved uneventfully. Minimally invasive lateral transthoracic trans/retropleural approach is a safe and efficacious technique for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional approaches.

Study design Ex vivo biomechanical evaluation using cadaveric vertebral bodies. Objective To compare the subsidence characteristics of a novel rectangular footplate design with a conventional circular footplate design. Summary of background data Cage subsidence is a postoperative complication after reconstruction of corpectomy defects in the thoracolumbar spine and depends on factors, such as bone quality, adjunctive fixation, and the relationship between the footplate on the cage and the vertebral body endplate. Methods Twenty-four cadaveric vertebrae (T12-L5) were disarticulated, potted in a commercial resin, loaded with either a circular or a rectangular footplate, and tested in a servo hydraulic testing machine. Twelve vertebral bodies were loaded with a circular footplate, and after subsidence the same vertebral bodies were loaded with a rectangular footplate. The second set of 12 vertebral bodies was loaded with a rectangular footplate only. Force-displacement curves were developed for the 3 groups, and the ultimate load to failure and stiffness values were calculated. Results The ultimate load to failure with the circular footplate was 1310 N (SD, 482). The ultimate load to failure with a rectangular footplate with a central defect and without a central defect was 1636 N (SD, 513) and 2481 N (SD, 1191), respectively. The stiffness of the constructs with circular footplate was 473 N/mm (SD, 205). The stiffness of the constructs with a rectangular footplate with a central defect and without a central defect was 754 N/mm (SD, 217) and 1054 N/mm (SD, 329), respectively. Conclusion A rectangular footplate design is more resistant to subsidence than a circular footplate design in an ex vivo biomechanical model. The new design had higher load to failure even in the presence of a central defect. These findings suggest that rectangular footplates may provide better subsidence resistance when used to reconstruct defects after thoracolumbar corpectomy.

Background context Few studies exist for magnetic resonance imaging (MRI) issues and ballistics, and there are no studies addressing movement, heating, and artifacts associated with ballistics at 3-tesla (T). Movement because of magnetic field interactions and radiofrequency (RF)-induced heating of retained bullets may injure nearby critical structures. Artifacts may also interfere with the diagnostic use of MRI. Purpose To investigate these potential hazards of MRI on a sample of bullets and shotgun pellets. Study design Laboratory investigation, ex vivo. Methods Thirty-two different bullets and seven different shotgun pellets, commonly encountered in criminal trauma, were assessed relative to 1.5-, 3-, and 7-T magnetic resonance systems. Magnetic field interactions, including translational attraction and torque, were measured. A representative sample of five bullets were then tested for magnetic field interactions, RF-induced heating, and the generation of artifacts at 3-T. Results At all static magnetic field strengths, non–steel-containing bullets and pellets exhibited no movement, whereas one steel core bullet and two steel pellets exhibited movement in excess of what might be considered safe for patients in MRI at 1.5-, 3- and 7-Tesla. At 3-T, the maximum temperature increase of five bullets tested was 1.7°C versus background heating of 1.5°C. Of five bullets tested for artifacts, those without a steel core exhibited small signal voids, whereas a single steel core bullet exhibited a very large signal void. Conclusions Ballistics made of lead with copper or alloy jackets appear to be safe with respect to MRI-related movement at 1.5-, 3-, and 7-T static magnetic fields, whereas ballistics containing steel may pose a danger if near critical body structures because of strong magnetic field interactions. Temperature increases of selected ballistics during 3-T MRI was not clinically significant, even for the ferromagnetic projectiles. Finally, ballistics containing steel generated larger artifacts when compared with ballistics made of lead with copper and alloy jackets and may impair the diagnostic use of MRI.

Study design A retrospective review of a case series. Objective To describe a novel surgical technique for a minimally disruptive lateral transthoracic transpleural approach to treat thoracic disc herniations. Summary of background data Thoracic disc herniation is a relatively uncommon spinal condition, and surgical treatment is indicated for patients with myelopathy or radiculopathy that failed to respond to conservative therapy. Presently there is no consensus about the best approach to address thoracic disc herniations. Using the novel retractor system (MaXcess), the authors describe a novel minimally disruptive approach that allows the surgeons to perform a standard anterior discectomy and fusion with instrumentation while minimizing approach-related morbidity. Methods A series of 12 patients with single-level thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through a novel retractor system is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed. Results Twelve patients were enrolled with an average age of 51 years (range, 23 to 67 y). The average follow-up was 28 months (range, 12 to 33 mo). The average length of hospital stay was 5 days (range, 2 to 12 d). The average preoperative visual analog scale pain score was 9 (range, 7 to 10), which later decreased to 3 (range, 0 to 5) at final follow-up. All patients with myelopathy and/or sphincter dysfunction had significant improvement of their symptoms. One patient had pleural effusion and 1 patient had intercostal neuralgia. Conclusions Anterior decompression using a transthoracic transpleural approach provides excellent exposure and allows consistent decompression of thoracic disc herniations. This study demonstrated that a new minimally invasive, transthoracic transpleural decompression technique can be safely performed for single-level thoracic disc herniations. The early results showed that this technique allows less dissection, along with the advantages of conventional thoracotomy.

Pseudoarthrosis after pedicle subtraction osteotomy (PSO) can require revision surgery due to posterior rod failure, and the stiffness of these revision constructs has not been quantified.To compare the multidirectional bending stiffness of 7 revision strategies following rod failure.Seven fresh-frozen human spines (T11-pelvis) were tested as follows: (1) posterior instrumentation from T12-S1 (excluding L3) with iliac fixation and L3 PSO; (2) inline connectors after rod breakage at L3 (L2 screws removed for access); (3) cross-links connecting rods above and below inline connectors; satellite rods (4) parallel, (5) 45° anterior, and (6) 45° posterior to original rods; 45° posterior with cross-links connecting (7) original and (8) satellite rods. Groups 3 to 8 were tested in random order. Nondestructive pure moment flexion-extension (FE), lateral bending (LB), and axial rotation (AR) tests were conducted to 7.5 Nm; 3D motion tracking monitored the primary range of motion.Addition of inline connectors alone restored stiffness in FE and LB (P.05), but not in AR (P.05). Satellite rods (groups 4 to 6) restored stiffness in FE and LB (P.05), but not in AR (P.05) and were not significantly different from one another (P.05). The addition of cross-links (groups 3, 7, and 8) restored stiffness in all bending modes (P.05) and were significantly greater than inline connectors alone in AR (P.05).The results suggest that these revision strategies can restore stiffness without entire rod replacement. Failure of AR stiffness restoration can be mitigated with cross-links. The positioning of the satellite rods is not an important factor in strengthening the revision.

STUDY DESIGN: Biomechanical laboratory research. OBJECTIVE: To characterize the structural stiffness of opening and closing wedge osteotomies and the independent effect of rod diameter. SUMMARY OF BACKGROUND DATA: Traditionally, C7 opening wedge osteotomy (OWO) has been performed for patients with ankylosing spondylitis. For patients without ankylosing spondylitis, closing wedge osteotomy (CWO) may be considered for more controlled closure. Biomechanical characteristics of the two osteotomy alternatives have not yet been analyzed. METHODS: Nondestructive pure moment flexion/extension (FE), lateral bending (LB), and axial rotation (AR) tests were conducted to 4.5 Nm on cadaveric specimens (C4-T3). All specimens underwent posterior bilateral screw-rod fixation with 3.5 mm and 4.5 mm Ti rods, whereas half received OWO and half received CWO. RESULTS: Independent of osteotomy type, constructs with 4.5 mm rods exhibited a significant increase in stiffness compared to 3.5 mm rods in all bending modes (P < 0.01). Relative to 3.5 mm rods, 4.5 mm constructs showed an increase in stiffness of 31 ± 12% for FE, 37 ± 39% for LB, and 31 ± 11% for AR. At the osteotomy site, there was a 43 ± 23% increase in FE stiffness, 45 ± 36% in LB, and 41 ± 17% in AR. Independent of rod diameter, CWO was significantly stiffer than OWO (42% for the construct and 56% across the osteotomy) in FE bending only (P < 0.05). CONCLUSION: The surgeon can expect a similar increase in stiffness in switching from 3.5 mm to 4.5 mm rod independent of osteotomy type. The increased stiffness of CWOs has an anatomic basis. OWOs disrupt the anterior longitudinal ligament (ALL) and leave a significant anterior gap whereas CWOs create a wedge through the vertebral body and leave the ALL and the discs above and below the osteotomy intact. The closure in CWOs leaves no anterior gap providing greater axial loading stability. This greater bone on bone contact in CWOs is likely a significant reason for the anterior stiffness and may provide greater fusion rates in the nonankylosing spondylitis patient population.

Ankylosing spondylitis (AS) is a genetic condition that frequently results in spinal sagittal plane deformity of thoracolumbar or cervicothoracic junctions. Generally, a combination of osteotomy and spinal fixation is used to treat severe cases. Although surgical techniques for traumatic injury across the cervicothoracic junction have been well characterized in clinical and biomechanical literature, the specific model of instrumented opening wedge osteotomy in autofused AS has not been studied biomechanically. This study characterizes the structural stability of various posterior fixation techniques across the cervicothoracic junction in spines with AS, specifically considering the effects of posterior rod diameter and material type.For each of 10 fresh-frozen human spines (3 male, 7 female; mean age 60 ± 10 years; C3-T6), an opening wedge osteotomy was performed at C7-T1. Lateral mass screws were inserted bilaterally from C-4 to C-6 and pedicle screws from T-1 to T-3. For each specimen, 3.2-mm titanium (Ti), 3.5-mm Ti, and 3.5-mm cobalt chromium (CoCr) posterior spinal fusion rods were tested. To simulate the anterior autofusion and long lever arms characteristic of AS, anterior cervical plates were placed from C-4 to C-7 and T-1 to T-3 using fixed angle screws. Nondestructive flexion-extension, lateral bending, and axial rotation tests were conducted to 3.0 Nm in each anatomical direction; 3D motion tracking was used to monitor primary range of motion across the osteotomy (C7-T1). Biomechanical tests used a repeat-measures test design. The order of testing for each rod type was randomized across specimens.Constructs instrumented with 3.5-mm Ti and 3.5-mm CoCr rods were significantly stiffer in flexion-extension than those with the 3.2-mm Ti rod (25.2% ± 16.4% and 48.1% ± 15.3% greater than 3.2-mm Ti, respectively, p0.05). For axial rotation, the 3.5-mm Ti and 3.5-mm CoCr constructs also exhibited a significant increase in rigidity compared with the 3.2-mm Ti construct (36.1% ± 12.2% and 52.0% ± 20.0%, respectively, p0.05). There were no significant differences in rigidity seen between the 3 types of rods in lateral bending (p0.05). The 3.5-mm CoCr rod constructs showed significantly higher rigidity in flexion-extension than the 3.5-mm Ti rod constructs (33.1% ± 15.5%, p0.05). There was a trend for 3.5-mm CoCr to have greater rigidity in axial rotation (36.2% ± 18.6%), but this difference was not statistically significant (p0.05).The results of this study suggest that 3.5-mm CoCr rods are optimal for achieving the most rigid construct in opening wedge osteotomy in the cervicothoracic region of an AS model. Rod diameter and material properties should be considered in construct strategy. Some surgeons have advocated anterior plating in patients with AS after osteotomy for additional stability and bone graft surface. Although this effect was not examined in this study, additional posterior stability achieved with CoCr may decrease the need for additional anterior procedures.