Biofilm growth has a threshold response to glucose in vitro.

BACKGROUND: Hyperglycemia is a risk factor for nosocomial infections with known host effects. Increased glucose levels also increase pathogenicity of infecting microbes through greater biofilm formation. The dose response of biofilm formation to glucose concentration is not known. QUESTIONS/PURPOSES: We asked: What is the relationship between the amount of biofilm formed by Staphylococcus epidermidis and Staphylococcus aureus and change in glucose concentration in the clinically important range of 20 to 300 mg/dL? METHODS: This experiment studied biofilm formation by S epidermidis and S aureus in Lennox broth medium supplemented with increasing glucose concentrations from 0 to 320 mg/dL in 20 mg/dL intervals. Biofilm was grown for 24 hours for S epidermidis and 48 hours for S aureus. Biofilms were heat fixed, stained with 0.1% crystal violet, and washed with deionized water. The dye was then extracted with 30% acetic acid. Visual light absorption of the extracted crystal violet dye at 600 nm was used to quantify the biofilm biomass. The effect of glucose concentration on the amount of biofilm mass produced was analyzed using ANOVA and Tukey's test. RESULTS: Biofilm mass was increased at higher glucose concentration for both species with a threshold response at 0 to 20 and 160 to 200 mg/dL for S epidermidis and 200 to 240 mg/dL for S aureus. CONCLUSIONS: Increased biofilm growth by S aureus and S epidermidis has a threshold response at clinically important concentrations. CLINICAL RELEVANCE: Postoperative hyperglycemia may increase the risk for implant infection through increased pathogenicity of intraoperative wound contaminants in addition to compromising host immune status.

Have levels of evidence improved the quality of orthopaedic research?

BACKGROUND: Since 2003 many orthopaedic journals have adopted grading systems for levels of evidence (LOE). It is unclear if the quality of orthopaedic literature has changed since LOE was introduced. QUESTIONS/PURPOSES: We asked three questions: (1) Have the overall number and proportion of Level I and II studies increased in the orthopaedic literature since the introduction of LOE? (2) Is a similar pattern seen in individual orthopaedic subspecialty journals? (3) What is the interobserver reliability of grading LOE? METHODS: We assigned LOE to therapeutic studies published in 2000, 2005, and 2010 in eight major orthopaedic subspecialty journals. Number and proportion of Level I and II publications were determined. Data were evaluated using log-linear models. Twenty-six reviewers (13 residents and 13 attendings) graded LOE of 20 blinded therapeutic articles from the Journal of Bone and Joint Surgery for 2009. Interobserver agreement relative to the Journal of Bone and Joint Surgery was assessed using a weighted kappa. RESULTS: The total number of Level I and II publications in subspecialty journals increased from 150 in 2000 to 239 in 2010. The proportion of high-quality publications increased with time (p < 0.001). All subspecialty journals other than the Journal of Pediatric Orthopaedics and the Journal of Orthopaedic Trauma showed a similar behavior. Average weighted kappa was 0.791 for residents and 0.842 for faculty (p = 0.209). CONCLUSIONS: The number and proportion of Level I and II publications have increased. LOE can be graded reliably with high interobserver agreement. The number and proportion of high-level studies should continue to increase.

Preoperative Dehydration does not Increase the Risk of Complications Following Elective Lumbar Surgery.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to evaluate the effect of preoperative dehydration on hospital length of stay (LOS), rates of 30-day postoperative complications, related reoperations, and readmissions. SUMMARY OF BACKGROUND DATA: Preoperative dehydration has long been associated with postoperative infection, deep vein thrombosis (DVT), acute renal failure, and an increased hospital LOS. To our knowledge, the effect of preoperative dehydration on complication rates for patients undergoing elective lumbar spine surgery has not been well described. METHODS: An analysis of American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) data from 2006 to 2013 was performed. Patients undergoing elective lumbar procedures were identified and exclusion criteria eliminated patients who underwent any emergency procedures, infections, tumor cases, or revision surgeries. Patient dehydration was defined as preoperative blood urea nitrogen/creatinine (BUN/Cr) ratio greater than 20. RESULTS: Patients (4698; 34.5%) with preoperative dehydration based on BUN/Cr ratio were identified. Univariate analysis was suggestive of an association between preoperative dehydration and an increased risk of DVT (1.1% compared with 0.6%; P = 0.002), urinary tract infection (2.5% compared with 1.6%; P < 0.001), and need for transfusion postoperatively (17.6% compared with 14.4%; P < 0.001). However, on the basis of multivariate regression, no significant association between dehydration and increased odds of aforementioned outcomes was identified. CONCLUSION: Preoperative dehydration does not appear to negatively affect perioperative outcomes or readmission in patients undergoing elective lumbar spine surgery. LEVEL OF EVIDENCE: 3.

Metabolic Syndrome and 30-Day Outcomes in Elective Lumbar Spinal Fusion.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to evaluate the effect of metabolic syndrome (MetS) on 30-day morbidity and mortality following elective lumbar spinal fusion. SUMMARY OF BACKGROUND DATA: MetS is a variable combination of hypertension, obesity, elevated fasting plasma glucose, and dyslipidemia.MetS has been associated with an increased risk of postoperative morbidity and mortality in multiple surgical settings. To our knowledge, the effect of MetS on 30-day outcomes following elective lumbar spinal fusion has not been well studied. METHODS: An analysis of ACS-NSQIP data was performed between 2006 and 2013. Patients undergoing elective posterior lumbar fusion were identified. Emergency procedures, infections, tumor cases, and revision surgeries were excluded. Patients were defined as having MetS if they had a history of hypertension requiring medication, diabetes, and a body mass index (BMI) ≥30 kg/m. RESULTS: One thousand five hundred ninety (10.2%) patients with MetS were identified. A mild increase in major (P = 0.040) and minor complications (P = 0.003) in patients with MetS was noted. MetS was associated with increased rates of pulmonary complications (1.9% compared with 1.0%; P = 0.001), sepsis (1.7% compared with 0.9%; P = 0.005), and acute post-op renal failure (0.4% compared with 0%; P < 0.001). Multivariate analysis confirmed MetS to be an independent predictor of pulmonary complications [odds ratio (OR) 1.51; 95% confidence interval (95% CI 1.00-2.27); P = 0.048], sepsis (OR 1.56; 95% CI 1.01-2.42; P = 0.039), and acute postoperative renal failure (OR 6.95; 95% CI 2.23-21.67; P = 0.001). MetS status was associated with a mild increase in total hospital length of stay (4.38 compared with 3.81 days; P < 0.001). CONCLUSION: While MetS is a predictor of postoperative acute renal failure, it only slightly increases the risk of overall complications and is not associated with increased rates of 30-day reoperations or readmissions following elective lumbar fusion. LEVEL OF EVIDENCE: 3.

Reverse Total Shoulder Arthroplasty for Posttraumatic Sequelae.

OBJECTIVES: The sequelae of proximal humeral fractures can produce severe shoulder dysfunction. We assessed the results of reverse shoulder arthroplasty (RSA) for these complex problems. DESIGN: Retrospective multicenter study. SETTING: Tertiary care referral hospitals. PATIENTS: A total of 26 patients were identified who had undergone RSA for the sequelae of proximal humeral fractures. Twenty patients had follow-up beyond 2 years, averaging 44 months (range, 27-97). Patients with revision prosthetic surgery were not included in the study. The average age at surgery was 67 years (range, 31-89). INTERVENTION: All patients underwent RSA. In addition, 4 shoulders required allografts to compensate for bone loss, and 1 shoulder concomitant internal fixation of a humeral shaft nonunion. MAIN OUTCOME MEASUREMENTS: The main outcome measurement was the Neer scale. Pain relief, range of motion, and American shoulder and elbow surgeon and Simple shoulder test shoulder outcome scores were also assessed. RESULTS: Overall results in the 20 patients were considered excellent in 8 shoulders, satisfactory in 6, and unsatisfactory in 6. There was significant improvement in the visual analog pain score to 1.9 (P = 0.005), forward elevation to 137 degrees (P < 0.001), and external rotation to 39 degrees (P = 0.0002). The mean American shoulder and elbow surgeon score was 65 and the mean Simple shoulder test 6. Complications included 1 deep infection, 2 transient brachial plexopathies, and 2 cases of dislocation. CONCLUSIONS: Reconstruction of the deformed proximal humerus from fracture sequelae with RSA is complex and often requires advanced surgical techniques. Complications are not infrequent and may require further surgery. Nevertheless, satisfactory results can be achieved in most patients. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Oblique Terminal Screw Placement: Does It Improve Fixation in Plate Osteosynthesis?

The technique of placing an oblique screw in the terminal hole of a plate to increase screw pullout strength is widely taught in the operating room. The origin of this technique is unclear; however, it may have been used simply as a means to identify radiographs and misinterpreted to have some biomechanical benefit. The objective of this study was to measure the structural effect of oblique terminal screw placement (OTSP) during plate osteosynthesis. Foam blocks and limited contact dynamic compression plates and screws were used along with a custom fixture device. The terminal screw was placed in either an oblique (30-degree angle outward) or perpendicular fashion. A load was applied perpendicular to the plate in cantilever bending until failure. The oblique screw construct was significantly weaker than the perpendicular screw construct (399N vs. 465N, P < 0.001), independent of the block of material used. Post hoc analysis showed that the screw angle (P < 0.001) was a significant determinant of the load required to cause screw pullout. OTSP led to a decrease in pullout strength compared with a perpendicular screw in a deformable foam medium similar in density to osteoporotic bone. In patients with poor bone quality, OTSP may create a suboptimal fracture fixation construct.

The Burden of Spinal Disorders in the Elderly.

Disorders of the spine are common and have a significant and measurable burden on affected patients and on our healthcare economy. The burden of spinal disorders encompasses metrics such as the prevalence of spinal disorders, the impact of spinal disorders on health-related quality of life, and the use of resources associated with the operative and nonoperative management of spinal disorders. Measurement of the burden of spinal disorders is important in prioritizing the distribution of limited resources within our healthcare economy. In 1998, the Priority Setting Committee of the Institute of Medicine concluded that in defining health priorities for research and funding, the burden of disease and impact on the health of the population should be the primary determinants of resource allocation. The purpose of this article is to report metrics comprising the burden of spinal disorders, with a focus on the significant and growing burden of spinal disorders in our elderly population, and to demonstrate that allocation of resources to the management of spinal disorders should be a priority for our healthcare economy.

A preliminary analysis of sleep-like states in the cuttlefish Sepia officinalis.

Sleep has been observed in several invertebrate species, but its presence in marine invertebrates is relatively unexplored. Rapid-eye-movement (REM) sleep has only been observed in vertebrates. We investigated whether the cuttlefish Sepia officinalis displays sleep-like states. We find that cuttlefish exhibit frequent quiescent periods that are homeostatically regulated, satisfying two criteria for sleep. In addition, cuttlefish transiently display a quiescent state with rapid eye movements, changes in body coloration and twitching of the arms, that is possibly analogous to REM sleep. Our findings thus suggest that at least two different sleep-like states may exist in Sepia officinalis.