Background Back pain attributable to lumbar disc herniation is a substantial cause of reduced workplace productivity. Disc herniation surgery is effective in reducing pain and improving function. However, few studies have examined the effects of surgery on worker productivity. Questions/purposes We wished to determine the effect of disc herniation surgery on workers’ earnings and missed workdays and how accounting for this effect influences the cost-effectiveness of surgery? Methods Regression models were estimated using data from the National Health Interview Survey to assess the effects of lower back pain caused by disc herniation on earnings and missed workdays. The results were incorporated into Markov models to compare societal costs associated with surgical and nonsurgical treatments for privately insured, working patients. Clinical outcomes and utilities were based on results from the Spine Patient Outcomes Research Trial and additional clinical literature. Results We estimate average annual earnings of $47,619 with surgery and $45,694 with nonsurgical treatment. The increased earnings for patients receiving surgery as compared with nonsurgical treatment is equal to $1925 (95% CI, $1121-$2728). After surgery, we also estimate that workers receiving surgery miss, on average, 3 fewer days per year than if workers had received nonsurgical treatment (95% CI, 2.4-3.7 days). However, these fewer missed work days only partially offset the assumed 20 workdays missed to recover from surgery. More fully accounting for the effects of disc herniation surgery on productivity reduced the cost of surgery per quality-adjusted life year (QALY) from $52,416 to $35,146 using a 4-year time horizon and from $27,359 to $4186 using an 8-year time horizon. According to a sensitivity analysis, the 4-year cost per QALY varies between $27,921 and $49,787 depending on model assumptions. Conclusions Increased worker earnings resulting from disc herniation surgery may offset the increased direct medical costs associated with surgery. After accounting for the effects on productivity, disc herniation surgery was found to be a highly cost-effective surgery and may yield net societal savings if the benefits of outpatient and inpatient surgery persist beyond 6 and 12 years, respectively. Level of Evidence Level II, economic and decision analysis. See the Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT: A direct lateral interbody fusion (DLIF) is relatively new, yet commonly performed procedure in spine surgery. This procedure is associated with risk, including damage to nerve or vascular structures. However, to our knowledge, there has not been a case of an abscess developing at the site of a postoperative hematoma after this procedure.PURPOSE: The objective was to document a case of the delayed presentation of an abscess at the site of a postoperative hematoma after a DLIF.STUDY DESIGN/SETTING: The study was designed to be a case report and literature review.METHODS: We present a case of a 63-year-old patient who developed a large retroperitoneal hematoma after an L2-L5 DLIF. The patient developed a postoperative urinary tract infection with cultures positive for Pseudomonas. The infection was treated with oral antibiotics. Eight months after her procedure, the patient was found to have developed an abscess (measuring 11.6 x 8.4 x 10.0 cm) at the site of the prior hematoma.RESULTS: After radiological-guided aspiration and a 2-week course of oral antibiotics, the abscess resolved and the patient recovered with no sequelae.CONCLUSION: Direct lateral interbody fusion is a minimally invasive procedure that may result in postoperative hematoma formation. We have reported a case of the development of an abscess at the site of a postoperative hematoma. (C) 2012 Elsevier Inc. All rights reserved.

Acute respiratory distress syndrome is rare after surgical procedures.After propensity analysis

BACKGROUND CONTEXT:Although clinical outcomes after lumbar disc herniations (LDHs) in the general population have been well studied, those in elite professional athletes have not. Because these athletes have different measures of success, studies on long-term outcomes in this patient population are necessary. PURPOSE:This study seeks to define the outcomes after an LDH in a large cohort of professional athletes of American football, baseball, hockey, and basketball. STUDY DESIGN/SETTING:Retrospective cohort study. PATIENT SAMPLE:A total of 342 professional athletes from four major North American sports from 1972 to 2008 diagnosed with an LDH were identified via a previously published protocol. Two hundred twenty-six players underwent lumbar discectomy, and 116 athletes were treated nonoperatively. Only those players who had at least 2 years of follow-up were included. OUTCOME MEASURES:Functional outcome measures as defined by successful return-to-play (RTP), career games, and years played for each player cohort were recorded both before and after treatment. Conversion factors based on games/regular season and expected career length (based on individual sport) were used to standardize the outcomes across each sport. METHODS:Using Statistical Analysis Software v. 9.1, outcome measures were compared in each cohort both before and after treatment using linear and mixed regression analyses and Cox proportional hazards models. A Kaplan-Meier survivorship curve was calculated for career length after injury. Statistical significance was defined as p<.05. RESULTS:After the diagnosis of an LDH, professional athletes successfully returned to sport 82% of the time, with an average career length of 3.4 years. Of the 226 patients who underwent surgical treatment, 184 successfully returned to play (81%), on average, for 3.3 years after surgery. Survivorship analysis demonstrated that 62.3% of players were expected to remain active 2 years after diagnosis. There were no statistically significant differences in outcome in the surgical and nonoperative cohorts. Age at diagnosis was a negative predictor of career length after injury, whereas games played before injury had a positive effect on outcome after injury. Major League Baseball (MLB) players demonstrated a significantly higher RTP rate than those of other sports, and conversely, National Football League (NFL) athletes had a lower RTP rate than players of other sports (p<.05). However, the greatest positive treatment effect from surgery for LDH was seen in NFL players, whereas for MLB athletes, a lumbar discectomy led to a shorter career compared with the nonoperative cohort (p<.05). CONCLUSIONS:Professional athletes diagnosed with an LDH successfully returned to play at a high rate with productive careers after injury. Whereas older athletes have a shorter career length after diagnosis of LDH, experienced players (high number of games played) demonstrate more games played after treatment than inexperienced athletes. Notably, surgical treatment in baseball players led to significantly shorter careers, whereas for NFL athletes, posttreatment careers were longer than those of the corresponding nonoperative cohort. The explanation for this is likely multifactorial, including the age at diagnosis, respective contractual obligations, and different physical demands imposed by each individual professional sport.

Unresectable malignant hilar strictures are difficult to palliate. SEMS have gained popularity based on publications showing superior short-term performance compared to plastic stents. However, SEMS may not be best suited for long-term palliation of complex (Bismuth type 3 and 4) hilar strictures.

Introduction: SEMS are rapidly becoming the preferred method to palliate malignant hilar biliary obstruction despite limited data regarding their superiority over plastic stents. We believe that SEMS are not appropriate for complex strictures in the liver hilum. Aim: Evaluate the outcomes of patients treated with plastic stents for complex malignant biliary obstruction. Methods: Retrospective review of all patients treated with plastic stenting for complex (Bismuth III & IV) hilar strictures between January 2001 and October 2008.

In this paper we present how Geometric Algebra can be used for deformation simulations. The aim is to capture the elastic behavior of simple components like rods. First we will review some other works in this field. Later we present an extended Finite Element Method, which has recently been developed and investigated. Our goal is a proof of concept that Geometric Algebra is able to improve Finite Element Methods. All algorithms presented in this paper work in real-time.

This work presents a method to simulate and render simple elastic objects with the help of a new mathematical language called Conformal Geometric Algebra. A simulation program has been developed to evaluate and test the acquired algorithm. Source code of a prototype has been written in the script language CLUCalc. A more efficient implementation has been created with C++. It is capable of providing a physically plausible behaviour of deformable objects and works in real-time. Diese Arbeit stellt eine Methode vor, mit der einfache elastische Objekte simuliert werden konnen. Hierbei wird die konforme geometrische Algebra, eine neue mathematische Sprache, benutzt. Ein Simulationsprogramm wurde entwickelt um den erarbeiteten Algorithmus zu testen. Ein Prototyp wurde mit Hilfe von CLUCalc erstellt. Eine effiziente Implementierung wurde mit C++ entwickelt. Damit ist es mogliche elastische Objekte und deren Verhalten physikalisch plausibel zu simulieren. Dies geschieht in Echtzeit.

Objectives: Corneal damage causes severe pain. This study investigated whether peripheral opioid receptors are present in the human cornea and assessed the efficacy of topical fentanyl in patients with corneal erosion.Methods: Immunohistochemical staining experiments were performed to examine the presence of both mu and delta-receptors on peripheral nerve fibers within human corneal tissue. In a randomized, double-blind clinical trial dexpanthenol (n = 20) or dexpanthenol plus 10 mu g fentanyl (n = 20) were topically applied every 4 hours to the eye of patients with a surgical intervention of corneal damage and subjective pain intensity was determined by a numerical rating scale.Results: Immunohistochemical staining identified peripheral nerve fibers in human cornea expressing both mu and delta-opioid receptors. In patients with corneal damage the ophthalmic intervention in local anesthesia decreased the subjective pain intensity significantly. At 4-hour intervals after the ophthalmic intervention, moderate pain intensity levels were not altered by the application of dexpanthenol with or without fentanyl. At 24 hours pain intensity dropped significantly, most likely owing to a natural decrease in pain, because the erosion was almost healed.Discussion: Both mu and delta-receptors are localized on nerve fibers within the cornea, which are accessible for topical opioid treatment. However, our formulation and dose of topical fentanyl in combination with dexpanthenol did not show any benefit in relieving pain from corneal erosion. Future studies are planned to determine the optimal protocol and dose of topical opioid treatment.

1Partners Orthopaedic Trauma Service, Massachusetts General Hospital, 55 Fruit Street, Yawkey 3600, Boston, MA 02118

Mobile ad-hoc networks (MANETs) that use geographic routing protocols may lead to a severe privacy breach since the current position of any node in the network can be resolved. By changing the node IDs frequently the location privacy of nodes can be achieved. It is disadvantageous that unicast communication between nodes is not possible any more. With the scheduled location transparency approach nodes know other nodes’ IDs at a pre-arranged start and end time. During this time interval a unicast communication is possible again.

We thank Cunha and Verri [1] for their constructive comments about our manuscript “Selective local PMN recruitment by CXCL1 or CXCL2/3 injection does not cause inflammatory pain” [2]. They raise several important issues concerning the role of polymorphonuclear cells (PMN), of chemokines, and of IL-1β in the induction of inflammatory hyperalgesia. Initially, the authors mention that their group has previously shown that certain chemokines and cytokines can induce hyperalgesia [3, 4], whereas in our study, chemokine (CXCL1, CXCL2/3) injection did not cause hyperalgesia. We agree with their comment that this discrepancy is most likely a result of different behavioral methods used. This issue is discussed in detail in our manuscript [2]. Cunha and Verri then show data that local PMN infiltration [measured indirectly by myeloperoxidase (MPO) activity] and mechanical hyperalgesia (measured by the von Frey test) are low in early inflammation [i.e., 2 h post-complete Freund’s adjuvant (CFA)] and increase in parallel within the first 6 h of CFA injection into the rat paw. Based on these correlative data they postulate that i) early time-points of inflammation are not ideal, and ii) PMN depletion at later time-points would be required to analyze the role of PMN in inflammatory hyperalgesia.