An implanted pH sensor read using radiography.

A biomedical sensor was developed to measure local pH near orthopedic implants to detect and study implant-associated infection. The sensor is read using plain radiography, a technique which is noninvasive, inexpensive, ubiquitously available in medical facilities, and routinely used in diagnosis and follow-up. The sensor comprises a radiopaque tungsten indicator pin embedded within a chemically responsive hydrogel that exhibits a pH-dependent swelling. A stainless steel well holds this hydrogel and attaches to an orthopedic plate. The local pH may be determined from the extent of hydrogel swelling by radiographically measuring the indicator position relative to the well. We calibrated the sensor in a series of standard pH buffers and tested it during bacterial growth in culture. The sensor was robust: its response was negligibly affected by changes in temperature, ionic strength within the normal physiological range, or long-term incubation with reactive oxygen species generated from hydrogen peroxide and copper. Pooled data from several sensors fabricated at different times and tested in different conditions had a root-mean-square deviation from a pH electrode reading of 0.24 pH units. Radiographic measurements were also performed in cadaveric tissue with the sensor attached to an orthopedic plate fixed to a tibia. Pin position readings varied by 100 µm between observers surveying the same radiographs, corresponding to 0.065 pH units precision in the range pH 4-8. The sensor was designed to augment standard radiographs of tissue, bony anatomy, and hardware by also indicating local chemical concentrations.

Allogeneic and Autogenous Bone Grafts Are Affected by Historical Donor Environmental Exposure.

BACKGROUND: Bone graft materials are routinely evaluated for infectious agents; however, data regarding contamination of bone graft from environmental exposure of the donors to osteotoxic substances such as lead are not routinely available. In animal models, stored lead in bone has been shown to impair fracture healing and osteocyte function. In clinical studies, lead is linked to skeletal disease at relatively low concentrations. Presumably the levels of lead in allografts mirror the level of lead in bone in the population; however, the degree to which processing might decrease this and the frequency with which potentially osteotoxic levels appear in bone grafts have not been studied. QUESTIONS/PURPOSES: (1) Does processing of donor bone for allografts result in lower concentrations of lead in commercial allograft when compared with autologous bone graft; and (2) what proportion of bone grafts contain potentially osteotoxic levels of lead from > 2.0 to 20.0 µg/g corresponding to environmental exposure? METHODS: Allograft from commercial sources and autologous bone graft materials were examined for lead content using ICP- atomic absorption spectrophotometric analysis. We analyzed bone graft specimens from 42 donors, including 26 corticocancellous tibial specimens from commercially available bone graft materials and 16 autograft corticocancellous tibial specimens. Lead levels were determined for the cortical (n = 42) and cancellous (n = 42) portions of each specimen. For quality control, all instruments, plastic and glassware, were regularly tested for lead contamination by atomic absorption spectrophotometry throughout the experiments. In addition, spectrophotometer calibration was verified using Standard Reference Material 1486 bone meal (NIST, Gaithersburg, MD, USA). Descriptive statistical analysis was performed using SPSS 20 (SPSS Inc, Chicago, IL, USA). Using these techniques, a lead level > 2 µg/g to 20 µg/g corresponds to some degree of environmental exposure to lead. RESULTS: With the numbers available in the present study, there were no differences in mean lead level between commercial bone graft materials and autogenous bone graft, 2.1 µg/g (95% confidence interval [CI], 1.6-3.3 µg/g) versus 2.0 µg/g (95% CI, 1.0-4.5 µg/g; p = 0.86). The range for all tested samples varied from < 0.1 to 5.0 µg/g. Likewise, there were no differences in mean lead level between cortical bone grafts, which contained 2.2 µg/g (95% CI, 1.5-3.7 µg/g), and cancellous grafts, which contained 1.9 µg/g (95% CI, 1.2-3.4 µg/g; p = 0.58). Thirty-eight percent (16 of 42) of the specimens had levels between 2.0 µg/g and 20 µg/g within a range expected for individuals with known environmental exposure to lead. CONCLUSIONS: This study demonstrates that lead is present in up to one-third of tibial allograft and autograft bone specimens at potentially osteotoxic levels regardless of the source or screening. Further research is needed to delineate the relationship with nonunion or pseudoarthrosis after procedures in which allograft is used. In addition, further study would examine concentrations of lead and other environmental contaminants in other graft types. CLINICAL RELEVANCE: Comparable levels of lead exposure have been associated with toxic effects on skeletal tissue. Further study of bone graft used in fusion procedures and other procedures is necessary to define the magnitude of osteotoxic effects in the setting of fracture care or fusion procedures.

The Role of Strategy in Health Care.

Significant changes are occurring in the health care field, and spine surgeons must have an understanding of business strategy if they are going to adapt to the new health care environment. Spine surgeons will be required to demonstrate how their service provides a unique value to their patients or else the patients will obtain care from competitors. Classic methods for demonstrating value such as academic prestige and superior clinical outcomes may no longer be sufficient in the evolving health care field, and surgeons will need to demonstrate a comprehensive and cost-effective treatment algorithm for a diagnosis. This article will discuss the basics of business strategy for the spine surgeon, and ways in which the surgeon may demonstrate value to their patients.

Managing the Delivery of Health Care: What Can Health Care Learn From the Business Community?

The passage of the Patient Protection and Affordable Care Act in March 2010 has resulted in dramatic changes to the delivery of health care in the United States toward a value-based system. While this is a significant change from the previous model, it presents an opportunity for high-quality health care providers to improve patient outcomes while also increasing revenue. However, those that lack a clear strategy to effectively implement change and communicate the increased value to the patients likely will suffer, regardless of how successful or prestigious they seem today.

Lateral Mass Fixation in the Subaxial Cervical Spine.

The use of lateral mass screws and rods in the subaxial spine has become the standard method of fixation for posterior cervical spine fusions. Multiple techniques have been described for the placement of lateral mass screws, including the Magerl, the Anderson, and the An techniques. While these techniques are all slightly different, the overall goal is to obtain solid bony fixation while avoiding the neurovascular structures. The use of lateral mass screws has been shown to be a safe and effective technique for achieving a posterior cervical fusion.

Variation in the management of thoracolumbar trauma and postoperative infection.

STUDY DESIGN: Multinational survey of spine trauma surgeons. OBJECTIVES: To survey spine trauma surgeons, examine the variety of management practices for thoracolumbar fractures, and investigate the need for future areas of study. BACKGROUND: Attempts to develop a universal thoracolumbar classification system represent the first step in standardizing treatment of thoracolumbar injuries, but there is little consensus regarding diagnosis and management of these injuries. METHODS: A survey questionnaire regarding a fictional neurologically intact patient with a burst fracture was administered to 46 spine surgeons. The questionnaire consisted of 2 domains: management of thoracolumbar fractures and management of postoperative infection. Survey results were compiled and evaluated and consensus arbitrarily assumed when the majority of surgeons agreed on a single question answer. RESULTS: Although majority consensus was reached on most questions, the interobserver reliability was poor. Consensus was achieved that magnetic resonance imaging should be performed during initial imaging. The majority would also operate regardless of magnetic resonance imaging findings, and would not operate at night. The favored technique was a posterior approach with decompression. Percutaneous fusion was considered a viable option by the majority of surgeons. No consensus was reached regarding instrumentation levels or construct length. The majority would use posterolateral bone grafting, and would not remove instrumentation nor perform an anterior reconstruction. Consensus was reached that postoperative bracing is unnecessary. Regarding management of infection, consensus was reached to use intraoperative vancomycin powder but not culture the nares before surgery. The majority used a set time period for antibiotic treatment when a drain was required, and would not apply supplementary bone graft at the time of final debridement and closure. CONCLUSIONS: There is lack of consensus regarding the appropriate management of thoracolumbar fractures. In the future, multicenter prospective studies are necessary to establish guidelines for the management of thoracolumbar fractures.

LITE-1 mediates behavioral responses to X-rays in Caenorhabditis elegans.

Rapid sensory detection of X-ray stimulation has been documented across a wide variety of species, but few studies have explored the underlying molecular mechanisms. Here we report the discovery of an acute behavioral avoidance response in wild type Caenorhabditis elegans to X-ray stimulation. The endogenous C. elegans UV-photoreceptor protein LITE-1 was found to mediate the locomotory avoidance response. Transgenic expression of LITE-1 in C. elegans muscle cells resulted in paralysis and egg ejection responses to X-ray stimulation, demonstrating that ectopic expression of LITE-1 can confer X-ray sensitivity to otherwise X-ray insensitive cells. This work represents the first demonstration of rapid X-ray based genetically targeted (X-genetic) manipulation of cellular electrical activity in intact behaving animals. Our findings suggest that LITE-1 has strong potential for use in this minimally invasive form of neuromodulation to transduce transcranial X-ray signals for precise manipulation of neural activity in mammals, bypassing the need for invasive surgical implants to deliver stimulation.

Measuring Orthopedic Plate Strain to Track Bone Healing Using a Fluidic Sensor Read via Plain Radiography.

OBJECTIVE: We describe a fluidic X-ray visualized strain indicator under applied load (X-VISUAL) to quantify orthopedic plate strain and inform rehabilitative care. METHODS: The sensor comprises a polymeric device with a fluidic reservoir filled with a radio-dense fluid (cesium acetate) and an adjoining capillary wherein the liquid level is measured. A stainless-steel lever attaches to the plate and presses upon the acrylic bulb with a displacement proportional to plate bending strain. The sensor was attached to a plate in a Sawbones composite tibia mimic and a human cadaveric tibia. An osteotomy model (5 mm gap) was used to simulate an unstable fracture, and allograft repair to simulate a stiffer healed fracture. The cadaveric and Sawbones tibia were cyclically loaded five times (0-400 N) using a mechanical test stand, and fluid displacement was measured from plain radiographs. RESULTS: The sensor displayed reversible and repeatable behavior with a slope of 0.096 mm/kg and fluid level noise of 50-80 micrometer (equivalent to 5-10 N). The allograft-repaired composite fracture was 13 times stiffer than the unstable fracture. CONCLUSION: An analysis of prior external fracture fixation studies and fatigue curves for internal plates indicates that the threshold for safe weight bearing should be 1/5th-1/10th of the initial bending for an unstable fracture. The precision of our device (<2% body weight) should thus be sufficient to track fracture healing from unstable through safe weight bearing. SIGNIFICANCE: The X-VISUAL fluidic sensor enables orthopedic plate strain quantification to monitor facture healing via X-ray imaging.

Do Inflammatory Cytokines Affect Patient Outcomes After ACDF?

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim was to determine the relationship between serum inflammatory mediators, preoperative cervical spine disease severity, and clinical outcomes after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Given the role of the inflammatory cascade in spinal degenerative disease, it has been hypothesized that inflammatory markers may serve as a predictor of patient outcomes after surgery. MATERIALS AND METHODS: All patients over age 18 who underwent ACDF for cervical spondylosis with associated radiculopathy and/or myelopathy between 2015 and 2017 from a single institution were prospectively recruited. Preoperative serum inflammatory markers including interleukin (IL)-6, IL-8, tumor necrosis factor-α, high-mobility group box-1 (HMGB1), and white blood cells were measured and correlated to patient demographics, surgical characteristics, duration of symptoms, previous opioid use, and preoperative and 1-year postoperative patient-reported outcomes measures (PROMs) including the neck disability index (NDI), visual analog scale neck pain, visual analog scale arm pain, and Physical and Mental Component Scores of the Short Form-12 (PCS and MCS, respectively) using spearman's rho coefficient. RESULTS: A total of 77 patients were enrolled with follow-up PROMs available for 62% (n=48) of patients at a minimum of 1-year after ACDF. The absolute concentrations of IL-6 and tumor necrosis factor-α were found to be weakly correlated with one another (ρ=0.479). Preoperative symptoms lasting <1-year were weakly correlated with elevation in HMGB1 (ρ=0.421). All other patient demographics exhibited negligible correlation with the preoperative inflammatory markers. Lower preoperative PCS (ρ=0.355) and higher preoperative NDI (ρ=0.336) were weakly correlated with elevated HMGB1. Lower MCS (ρ=0.395) and higher NDI (ρ=0.317) preoperatively were weakly correlated with elevated white blood cells. Postoperative improvement in MCS (ρ=0.306) and MCS recovery ratio (ρ=0.321) exhibited a weakly positive correlation with IL-6. CONCLUSION: Preoperative cytokine levels demonstrated minimal correlation with preoperative symptoms or clinical improvement, suggesting that profiling of patient cytokines has limited utility in predicting outcomes after ACDF. LEVEL OF EVIDENCE: Level III.

Management of West Nile Encephalitis: An Uncommon Complication of West Nile Virus.

West Nile virus disease (WNVD) is a mosquito-borne disease that affects the meninges and central nervous system, causing West Nile virus (WNV) encephalitis, a debilitating, life-threatening condition, especially in the elderly. While there is a lot of research discussing different aspects of the disease, the treatment is mainly unknown. We conducted a literature review to explore the wide variety of treatment options that consolidate the knowledge about the most recent management of WNV encephalitis. We did a combined advanced search and Medical Subject Headings (MeSH) search on PubMed. Inclusion criteria included papers written in the English language and human subjects research for the past 25 years. We initially gather 110 papers, and after applying the inclusion/exclusion criteria, we end up with 30 articles for the paper's discussion. This review aims to provide clinicians with an overview of the latest approach in treating and managing hospitalized WNVD patients. It discusses case reports and the outcome of different treatment regimens done in vitro and in vivo. The study discusses all the advancements in treatment and prophylaxis and compares their effectiveness. However, more research is warranted to gain further insight to develop a single guideline for the management of this disease. This review discusses the following treatment modalities: ribavirin, interferon-alpha, intravenous immunoglobulin (IVIG), and other less-used drugs. More studies about ribavirin are needed to know if the drug is useful for WNV encephalitis. Interferon-alpha has been shown to have both protective and disease limiting properties. At the moment, there are no guidelines for the treatment of WNV encephalitis, nor is there a single Food and Drug Administration (FDA)-approved drug. For the time being, IVIG offers the best results in treating WNV encephalitis.

Calcium-Alkali Syndrome: Historical Review, Pathophysiology and Post-Modern Update.

Milk-alkali syndrome or calcium-alkali syndrome (CAS) is the triad of hypercalcemia, metabolic alkalosis and renal impairment. It is often related to ingestion of high amounts of calcium carbonate, which was used historically for the treatment of peptic ulcer disease. The incidence of the syndrome decreased dramatically after the introduction of newer peptic ulcer medications such as proton pump inhibitors and histamine blocking agents. However, a resurgence was seen in the late 1980s with the wide use of over-the-counter calcium supplements, mainly by females for osteoporosis prophylaxis. The modern version of the syndrome continues to evolve along with medical management. This review focuses on the historical context of CAS, pathogenesis, resurgence of the condition with variable presentations, and contemporary management.

Prevalence of Fabry Disease in Patients With Cryptogenic Strokes: A Systematic Review.

Fabry disease (FD) is an X-linked disorder involving multiple organs. Stroke is a serious and frequent complication of FD. Cryptogenic stroke is a common presentation of FD, especially in the young population. The etiology of cryptogenic stroke is highly variable and difficult to assess, frequently leaving patients without a primary diagnosis. We conducted a systematic review to investigate the pooled prevalence of FD among patients with cryptogenic stroke, or patients with FD in whom a stroke was the presenting condition. English-language studies involving humans published in the last 20 years were included in this systematic review. FD was more common in male patients and tended to present at an earlier age. The frequency of hemorrhagic and ischemic strokes in this population was similar to that in the general population. There was a high rate of stroke recurrence in the study sample, even among patients undergoing enzyme replacement therapy. We conclude that screening for FD in patients with cryptogenic stroke is low yield and not cost-effective. However, it may be worthwhile to screen for FD among patients with recurrent strokes.

Babesiosis: Appreciating the Pathophysiology and Diverse Sequela of the Infection.

Babesiosis is a blood-borne disease found mainly in the United States caused by a parasitic piroplasm. While most infections are mild to moderate in immunocompetent hosts, life-threatening complications can occur in those with significant comorbidities like congestive heart failure (CHF) or chronic obstructive pulmonary disease (COPD). There is sparse literature discussing the complications of Babesia microti infection or the pathophysiology and management thereof. A literature review was conducted to consolidate the current knowledge about the disease, pathophysiology, and proposed management of all potential complications based on risk factors and other clinical information. A MeSH cross-references strategy was employed in PubMed using the search terms "babesia" and "babesiosis" and the established associated conditions, and the search expanded to increase capture. Only papers written in the English language and discussing human subjects in the North American patient population were included. The initial search yielded 315 papers and, after applying the inclusion/exclusion criteria, a final number of 18 was reviewed. The various complications and pathophysiology thereof are then discussed according to organ system. Babesia is a subversive parasite associated with a variety of conditions. We hope a better appreciation of all potential presentations and complications will help clinicians manage this increasingly common zoonosis and reduce adverse effects. More research is recommended into the pathophysiology and prevention of complications following this and other tick-borne illnesses.

Luminescent Spectral Rulers for Noninvasive Displacement Measurement through Tissue.

A luminescent spectral ruler was developed to measure micrometer to millimeter displacements through tissue. The spectral ruler has two components: a luminescent encoder patterned with alternating stripes of two spectrally distinct luminescent materials and an analyzer mask with periodic transparent windows the same width as the encoder stripes. The analyzer mask is placed over the encoder and held so that only one type of luminescent stripe is visible through the window; sliding the analyzer over the encoder modulates the luminescence spectrum acquired through the analyzer windows, enabling detection of small displacements without imaging. We prepared two types of spectral rulers, one with a fluorescent encoder and a second with an X-ray excited optical luminescent (XEOL) encoder. The fluorescent ruler used two types of quantum dots to form stripes that were excited with 633 nm light and emitted at 645 and 680 nm, respectively. Each ruler type was covered with chicken breast tissue to simulate implantation. The XEOL ruler generated a strong signal with negligible tissue autofluorescence but used ionizing radiation, while the fluorescence ruler used non-ionizing red light excitation but required spectral fitting to account for tissue autofluorescence. The precision for both types of luminescent spectral rulers (with 1 mm wide analyzer windows, and measured through 6 mm of tissue) was <2 µm, mostly limited by shot noise. The approach enabled high micrometer to millimeter displacement measurements through tissue and has applications in biomechanical and mechanochemical measurements (e.g., tracking postsurgical bone healing and implant-associated infection).

Comparison of Surgical Outcomes of the Posterior and Combined Approaches for Repair of Cervical Fractures in Ankylosing Spondylitis.

STUDY DESIGN: Retrospective cohort study. PURPOSE: To evaluate surgical outcomes and complications of cervical spine fractures in ankylosing spondylitis (CAS) patients who were treated using either the posterior (P) or combined approach (C). OVERVIEW OF LITERATURE: Ankylosing spondylitis typically causes progressive spinal stiffness that makes patients susceptible to spinal fractures. CAS is a highly unstable condition. There is contradictory evidence regarding which treatment option, the posterior or the combined approach, yields superior clinical results. METHODS: A single institution database was reviewed for data in the period 1999 to 2015. All CAS patients who underwent posterior or combined instrumented fusion were enrolled. We analyzed demographic data, radiographic results, perioperative complications, and postoperative results. RESULTS: Thirty-three patients were enrolled (23 in the P group, 10 in the C group). All patients presented with neck pain after a fall. In the P group, mean operative time was 161.1 minutes (100-327 minutes), and mean estimated blood loss (EBL) was 306.4 mL (50-750 mL). In the C group, 90% of patients underwent a staged procedure, typically with posterior surgery first. Mean EBL was 124 mL (25-337 mL). For posterior surgery, mean EBL was 458.3 mL (400-550 mL). EBL of posterior surgery in the C group was higher but this difference was not significant (p=0.16). Postoperative complication rate was higher in the C group but this difference was not significant (50% vs. 17.4%, p=0.09). In the follow-up period, no late reoperations were performed. Patients who underwent C surgery had a higher rate of neurological improvement but this difference was not significant (p=0.57). CONCLUSIONS: Both P and C provided good clinical results. P surgery had lower EBL, lower postoperative complication rate, and shorter length of stay than C surgery; none of these differences were statistically significant.

Risk Factors for Pseudarthrosis After Surgical Site Infection of the Spine.

BACKGROUND: Pseudarthrosis following spinal fusion is a complication that frequently requires revision surgery. Reported rates of pseudarthrosis after surgical site infection (SSI) range from 30% to 85%, but few studies have identified infection as an independent risk factor for its development. The purpose of this study was to determine the incidence of clinically symptomatic pseudarthrosis in patient who developed SSI following lumbar fusion and to identify factors associated with its development. METHODS: This was a retrospective review of a prospectively collected database. Patients who underwent spinal surgery and developed SSI between January 2005 and March 2015 with a minimum 2-year follow-up were included. Patient-specific and procedural characteristics were recorded. Presence of pseudarthrosis was determined clinically by the treating surgeon and was confirmed radiographically. All those in the Pseudarthrosis group required a revision procedure after the eradication of infection. Univariate and multivariate analyses were conducted as appropriate. RESULTS: A total of 416 patients were included. Of these, 21 (5.0%) developed symptomatic pseudarthrosis following SSI. In this cohort, multivariate regression showed that age, Charlson Comorbidity Index, male sex, and surgical approach were not significant predictors of pseudarthrosis formation. However, number of levels fused was found to be the leading predictor for pseudarthrosis development (odds ratio [OR], 1.356/level, P < .001), followed by body mass index (OR, 1.083/point, P < .009) in this cohort. The number of levels fused was found to be a significant predictor of hardware removal (OR, 1.190/level, P < .001). Of the 21 pseudarthrosis cases, 85.7% found staphylococcal species, of which 27.8% exhibited methicillin-resistant Staphylococcus aureus. CONCLUSIONS: The number of spinal levels fused and body mass index are independent predictors of pseudarthrosis in patients who develop SSI after spinal fusion. LEVEL OF EVIDENCE: Level 4. CLINICAL RELEVANCE: This is the first known study to specifically identify risk factors for the development of symptomatic pseudarthrosis.

Cervical Sagittal Range of Motion as a Predictor of Symptom Severity in Cervical Spondylotic Myelopathy.

STUDY DESIGN: A retrospective review of radiographic data and functional outcomes. OBJECTIVE: The aim of this study was to evaluate whether myelopathy symptom severity upon presentation corresponds to sagittal plane alignment or nonmyelopathy symptoms, such as pain, in patients with cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA: Cervical sagittal balance is an important parameter in the outcome of surgical reconstruction. However, the effect of sagittal alignment on symptom severity in patients who have not undergone spine surgery is not well defined. METHODS: A consecutive series of CSM patients was identified at an academic institution. Preoperative radiographs were analyzed for sagittal vertical axis (C2SVA), C7 slope (C7S), C2-C7 angle in neutral (C27N), flexion (C27F), and extension (C27E), and range of motion (C27ROM). Neutral alignment was categorized as lordotic, kyphotic, or sigmoid/straight. Outcomes collected were SF-12, neck disability index, arm pain, neck pain, and modified JOA (mJOA). Pearson coefficients determined correlations between radiographic and outcome parameters. Multivariate regression evaluated predictive factors of mJOA. RESULTS: Radiographic parameters did not correlate with pain. Increasing age, smaller C27ROM, and smaller flexion angles correlated to lower (more severe) baseline mJOA scores. ROM (and not static alignment) was the only significant predictor of mJOA in the multivariate regression. Despite significant radiographic differences between lordotic, kyphotic, and sigmoid/straight alignment groups, myelopathy severity did not differ between these groups. CONCLUSION: Static, neutral alignment, including SVA and lordosis, did not correlate with myelopathy or pain symptoms. Greater C27ROM and increased maximal flexion corresponded to milder myelopathy symptoms, suggesting that patients with myelopathy may compensate for cervical stenosis with hyperflexion, similar to that which is observed in the lumbar spine. In a CSM patient population, dynamic motion and compensatory deformities may play a more significant role in myelopathy symptom severity than what can be discerned from standard, neutral position radiographs. LEVEL OF EVIDENCE: 3.

Reliability and Clinical Utility of the CARDS Classification for Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of this study is to determine the reliability and clinical utility of the of the proposed CARDS classification for degenerative spondylolisthesis. BACKGROUND: The Clinical and Radiographic Degenerative Spondylolisthesis (CARDS) classification system was recently proposed as an alternative to the Meyerding system for classifying degenerative spondylolisthesis (DS). Unlike Meyerding, CARDS considers other relevant radiographic findings such as disk space collapse and segmental kyphosis to stratify DS into 4 radiographically discreet types. Currently, no studies have been conducted to assess the clinical utility of the CARDS system. METHODS: A total of 78 consecutive surgical patients with L4-L5 DS were rated as CARDS types A through D and Fleiss' κ for interobserver agreement was calculated. Then, demographics as well as preoperative and postoperative outcome scores (ODI, SF-12 mental and physical, VAS) were collected. The Kruskal-Wallis test was used to detect significant differences amongst CARDS types. An unpaired t test was used to compare individual CARDS types with all other subtypes combined. RESULTS: Grading showed: 4 type A, 19 type B, 45 type C, and 8 type D (k=0.63). There was a statistically significant difference in preoperative back pain (P=0.046) between groups. CARDS type D had the highest mean back pain scores (8.8) of all subtypes which was significantly higher than mean back pain for all other subtypes combined (P=0.016). CARDS D showed the largest degree of improvement in all outcome measures. There was a trend towards an increased improvement in ODI (P=0.074) and SF-12 MCS (P=0.095) in the CARDS D subtype relative to the rest of the cohort. CONCLUSIONS: The CARDS classification system represents a reliable method for classifying cases of DS. Our results indicate that kyphotic segmental alignment (CARDS D) may be a less common, yet clinically distinct subset of DS characterized by worse preoperative back pain. CARDS type D cases may also show a greater degree of improvement in multiple outcome measures following surgical intervention.

Outcome of a Resident Spine Surgical Skills Training Program.

STUDY DESIGN: Cadaver training lab. OBJECTIVE: To determine if a technical cadaver skills training lab for spinal surgery increases resident confidence, satisfaction in training, and perception of operating room safety. SUMMARY OF BACKGROUND DATA: Resident training is an important topic in the setting of work hour reform. The use of supplemental materials such as videos, sawbones, and simulators may become important to adequately train orthopedic residents. At present, there are no established curricula for training orthopedic surgery residents on anatomy and common procedures encountered during a spinal surgery rotation. METHODS: Residents were assembled into teams of a PGY-5 and PGY-2 and/or PGY-1 to perform dissection and procedures on 5 fresh-frozen spine cadavers. With attending and spine fellow supervision, residents performed anterior cervical, posterior cervical, and posterior thoracolumbar surgical exposure, decompression, and fusion procedures in the operating room using surgical tools and instrumentation. Residents were then queried about their confidence levels, satisfaction in training, and perception of safety using a Likert scale (0-10). Strong agreement (scores ≥8) and strong disagreement (scores ≤3) and correlations were evaluated. RESULTS: Seventeen residents completed the training program (7 PGY-1s, 2 PGY-2s, and 8 PGY-5s). After the training, the majority of residents strongly agreed that they had an increased confidence of their own abilities (59%). A significant majority (65%) of residents strongly agreed that they were satisfied with the benefits provided by the training program. Compared with other methods of education, residents strongly agreed that the training was more helpful than textbook chapters (94%), sawbones (94%), web-based training (94%), or a virtual-based (completely electronic) training (94%). After the training, residents strongly agreed that the training improved feelings of preparation (47%), safety (41%), and ability to prevent intraoperative errors (41%). The vast majority of residents strongly agreed "Before performing surgery on me, I would want a resident to perform this cadaveric training" (88%). CONCLUSIONS: These results demonstrate that team-based, cadaveric training with adequate attending supervision, before onset of a spine surgical rotation, may lead to high resident confidence, satisfaction in training, and perception of patient safety.

Delayed Bone Infarct in the Ilium Following a Pelvic Crush Injury and Embolization: A Case Report.

CASE: We present a case of delayed osteonecrosis of the ilium. After receiving embolization and multiple orthopaedic procedures following a complex pelvic crush injury, the patient subsequently developed posterior pelvic pain and tenderness over the posterior superior iliac spine, along with pain on sacroiliac joint compression. Magnetic resonance imaging of the pelvis demonstrated a bone infarction in the left ilium adjacent to the sacroiliac joint. CONCLUSION: The symptoms from osteonecrosis of the ilium may simulate sacroiliitis or other conditions. It is important to keep the differential diagnosis in mind when considering additional management for posterior pelvic pain in the setting of prior trauma and preexisting hardware.