Higher Initial Failure Research Articles

Benefit of spinal cord stimulation for patients with central poststroke pain: a retrospective multicenter study.

Spinal cord stimulation (SCS) has been considered an ineffective procedure for patients with central poststroke pain (CPSP). However, recent case series that included small numbers of patients reported the possible efficacy of SCS as a treatment of CPSP. This multicenter retrospective study aimed to examine the outcomes of using SCS to treat patients with CPSP and to explore factors related to outcomes. The authors reviewed the medical records of patients with CPSP who underwent SCS to collect data regarding their background, surgical information, and outcomes of SCS at trial stimulation and last follow-up after long-term implantation in six study centers. Outcomes were evaluated with a pain score for intensity (range 0-10) and the Patient Global Impression of Changes (PGIC) scale. Factors associated with outcomes were explored with univariable and multivariable analyses. The authors collected data from a total of 166 patients (mean age 63.4 years; mean pain score at baseline 8.2). Of these patients, 163 underwent trial stimulation. The mean pain score decreased by 42.0%, 104 (64%) patients had ≥ 30% decrease in pain score, and 96 (59%) reported much or very much improved condition on the PGIC scale at trial stimulation. Moreover, 106 (64%) patients underwent long-term implantation of SCS devices. The mean decrease in pain score was 41.4%, 63 (59%) patients continued to show ≥ 30% decrease in pain score at last follow-up, and 60 (56%) reported much or very much improved condition on the PGIC scale at last follow-up (median [range] follow-up period 24 [24-63] months). Eleven device-related complications and 10 permanent explantations were observed. Univariable and multivariable analyses suggested that young age, less sensory disturbance, implantation of cervical leads, treatment of upper-limb pain, and extensive treated regions were associated with satisfactory outcomes at last follow-up after long-term implantation. These findings indicate that SCS may modestly benefit patients with CPSP. SCS has therapeutic potential for patients with intractable CPSP owing to the lower invasiveness of the SCS procedure and refractory nature of CPSP. Nevertheless, trial stimulation is necessary because of the high initial failure rate.

The Impact of Encouraging Social Promotion

I study the effects of encouraging social promotion in the context of a policy in Colombia that capped the number of failing students at 5% of the total school enrollment. I show that this reform decreased failure rates by 10 percentage points in schools with high initial failure. To estimate the impacts on school dropout and student academic achievement, I exploit variation in the extent to which the 5% cap was binding across schools based on their pre-policy rates. I find that average math and language test scores are lower for cohorts that had more years of exposure to the social promotion regime. In addition, I find that dropout rates decreased by 25%, suggesting an overall ambiguous effect of this policy. I provide suggestive evidence that the impacts might be driven by both a composition and an incentive effect.

The efficiency and effectiveness of municipally owned corporations: a systematic review

ABSTRACTMunicipally owned corporations (MOCs) are increasingly utilised to provide local public services, but little remains known about their efficiency and effectiveness. In this article, we offer a typology of MOCs, explore the variables that affect their behaviour, and perform a systematic review of public administration articles published between 2001 and 2015 on their efficiency and effectiveness. We find that MOCs are often more efficient than local bureaucracies in the provision of services such as refuse collection, water distribution, and transit services, although they also have high initial failure rates. We conclude that municipally owned corporations are a viable means for delivering some local public services for localities capable of initiating and managing complex contracts. In light of the scarcity of literature on this topic, our conclusions remain tentative, and we encourage additional research into this growing phenomenon.

Strategic optimization in R&D investment

We use d'Aspremont and Jacquemin's strategic optimal R&D investment in a duopoly Cournot competition model to construct myopic optimal discrete and continuous R&D dynamics. We show that for some high initial production costs, the success or failure of a firm is very sensitive to small variations in its initial R&D investment strategies.

Treatment of Adults with Complications from Previous Hypospadias Surgery

Adults with complications from previous hypospadias surgery experience various problems, including urethral stricture, persistent hypospadias and urethrocutaneous fistula. Innate deficiencies of the corpus spongiosum and multiple failed operations makes further management challenging. We reviewed our prospective urethroplasty database of men who presented with complications of previous hypospadias surgery. Patients were included in study if they had greater than 6 months of followup. Our surgical management was defined as an initial success if there were no urethral complications. The overall success rate included men with the same result after additional treatment. A total of 50 men had followup greater than 6 months (median 89) and were included in study. These 50 patients presented with urethral stricture (36), urethrocutaneous fistula (12), persistent hypospadias (7), hair in the urethra (6) and severe penile chordee (7). Patients underwent a total of 74 urethroplasties, including stage 1 urethroplasty in 19, a penile skin flap in 11, stage 2 urethroplasty in 11, urethrocutaneous fistula closure in 9, permanent perineal urethrostomy in 6, excision and primary anastomosis in 6, a 1-stage buccal mucosa onlay in 4, tubularized plate urethroplasty in 3, combined techniques in 3 and chordee correction in 1. In 25 men (50%) treatment was initially successfully. Of the 25 men in whom surgery failed 18 underwent additional procedures, including 13 who were ultimately treated successfully for an overall 76% success rate (38 of 50). Managing problems from previous hypospadias surgery is difficult with a high initial failure rate. Additional procedures are commonly needed.

Burn-in for Systems Operating in a Shock Environment

Burn-in is a widely used engineering method to eliminate defective items before they are shipped to customers or put into field operation. Burn-in procedures are usually applied to items with high initial failure rate which operate under a static operational environment. In this paper, we consider burn-in for items that operate in an environment with shocks. We assume that there are two competing risk causes of failure: the `usual' degradations, and environmental shocks. A new type of burn-in via controlled (laboratory) test shocks is considered, and the problem of obtaining the optimal level (severity) of these shocks is investigated. Furthermore, we combine the conventional burn-in procedure with burn-in via shocks in one unified model.

Initial load-to-failure and failure analysis in single- and double-row repair techniques for rotator cuff repair

AimThis experimental study aimed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture materials. Additionally, the mode of failure of each repair was evaluated.MethodIn 32 sheep shoulders, a standardized tear of the infraspinatus tendon was created. Then, n = 8 specimen were randomized to four repair methods: (1) Double-row Anchor Ethibond® coupled with polyester sutures, USP No. 2; (2) Double-Row Anchor HiFi® with polyblend polyethylene sutures, USP No. 2; (3) Single-Row Anchor Ethibond® coupled with braided polyester sutures, USP No. 2; and (4) Single-Row Anchor HiFi® with braided polyblend polyethylene sutures, USP No. 2. Arthroscopic Mason–Allen stitches were placed (single-row) and combined with medial horizontal mattress stitches (double-row). All specimens were loaded to failure at a constant displacement rate on a material testing machine.ResultsGroup 4 showed lowest load-to-failure result with 155.7 ± 31.1 N compared to group 1 (293.4 ± 16.1 N) and group 2 (397.7 ± 7.4 N) (P < 0.001). Stiffness was highest in group 2 (162 ± 7.3 N/mm) and lowest in group 4 (84.4 ± 19.9 mm) (P < 0.001). In group 4, the main cause of failure was due to the suture cutting through the tendon (n = 6), a failure case observed in only n = 1 specimen in group 2 (P < 0.001).ConclusionsA double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used.

Bilateral brucellar breast abscess in a 48-year-old woman

Bilateral brucellar breast abscess in a 48-year-old woman

Initial Adherence to Autotitrating Positive Airway Pressure Therapy: Influence of Upper Airway Narrowing

ObjectivesThere is still debate concerning the reason for the high initial failure rate of positive airway pressure (PAP) treatment. The objective of this study is to investigate the factors of the initial adherence to PAP, with an emphasis on the role of upper airway narrowing.MethodsThe patients were divided into two groups according to the continuation of therapy within the first three months of treatment. The demographic and polysomnographic findings, the minimal nasal cross sectional area (MCA), the degree of palatine tonsilar hypertrophy (PTH) and the modified Mallampati grade of the oropharynx inlet (Orophx) were compared between the study groups.ResultsAmong 36 patients, 23 continued the auto-adjusting positive airway pressure (APAP) therapy (the adherent group) and 13 discontinued APAP within three months (the non-adherent group). The apnea-hypopnea index (AHI) was significantly higher in the adherent group than in the non-adherent group (P<0.001). The AHI distributions of the two groups are extremely different. Thirteen of the 23 patients in the adherent group had an AHI of more than 60/hr, while none of the patients in the non-adherent group had an AHI of more than 60/hr. In the patients with an AHI from 15 to 60/hr, the MCA at the wide side of the nasal cavity and the sum of the MCAs of both sides were significantly larger in the adherent group than those values in the non-adherent group (P=0.004). The PTH and the Orophx were not significantly different between the two groups.ConclusionAHI is a definite significant factor of adherence to APAP therapy. The dimension of the nasal cavity has an influence on initial APAP adherence in the patients who have a not too high level of AHI.

Obstetric anesthesia for the obese and morbidly obese patient: an ounce of prevention is worth more than a pound of treatment

The incidence of obesity has been dramatically increasing across the globe. Anesthesiologists, are increasingly faced with the care for these patients. Obesity in the pregnant woman is associated with a broad spectrum of problems, including dramatically increased risk for cesarean delivery, diabetes, hypertension and pre-eclampsia. A thorough understanding of the physiology, associated conditions and morbidity, available options for anesthesia and possible complications is therefore important for today's anesthesiologist. This is a personal review in which different aspects of obesity in the pregnant woman, that are relevant to the anesthesiologist, are discussed. An overview of maternal and fetal morbidity and physiologic changes associated with pregnancy and obesity is provided and different options for labor analgesia, the anesthetic management for cesarean delivery and potential post-partum complications are discussed in detail. The anesthetic management of the morbidly obese parturient is associated with special hazards. The risk for difficult or failed intubation is exceedingly high. The early placement of an epidural or intrathecal catheter may overcome the need for general anesthesia, however, the high initial failure rate necessitates critical block assessment and catheter replacement when indicated.

DISSOLVING STOCK DISCRETENESS WITH SATELLITE TRACKING: BOWHEAD WHALES IN BAFFIN BAY

AbstractNine bowhead whales (Balaena mysticetus) were instrumented with satellite transmitters in West Greenland in May 2002 and 2003. Transmitters were either encased in steel cans or imbedded in floats attached to wires. Transmitters mounted in steel cans had a high initial failure rate, yet those that were successful provided tracking durations up to seven months. Float tags had a low initial failure rate and initially provided large numbers of positions; however, they had deployment durations of only 2–33 d. All tracked whales departed from West Greenland and headed northwest towards Lancaster Sound in the end of May. Three tags with long tracking durations (197–217 d) recorded movements of whales (1 ♂, 2 ♀) into December in 2002 and 2003. All of these individuals remained within the Canadian High Arctic or along the east coast of Baffin Island in summer and early fall. By the end of October, all three whales moved rapidly south along the east coast of Baffin Island and entered Hudson Strait, an apparent wintering ground for the population. One of the whales did not visit Isabella Bay on east Baffin Island, the locality used for abundance estimation from photographic reidentification of individuals. The movements of whales tagged in this study raise critical questions about the assumed stock discreteness of bowhead whales in Foxe Basin, Hudson Strait, and Davis Strait and indicate current estimates of abundance are negatively biased.

Implementation of new surgical technology: outcome measures for lymphatic mapping of breast carcinoma.

Recent advances in technology and the subsequent development of minimally invasive surgical techniques have heralded a new era in the surgical treatment of breast cancer. The dilemma of how to train surgeons in new technologies requires teaching, certification, and outcomes reporting in a non-threatening and non-economically damaging manner. This study examines 700 cases of lymphatic mapping and sentinel lymph node (SLN) biopsy for breast cancer and documents surgeon-specific and institution-specific learning curves. Seven hundred cases of lymphatic mapping and SLN biopsy were examined. All procedures were performed using a combination of vital blue dye and radiolabeled sulfur colloid. Learning curves were generated for each surgeon as a plot of failure rate versus number of cases. Examination of the learning curves in this study demonstrates similar characteristics. Following a high initial failure rate, there is a rapid decrease after the first twenty cases. The learning curve, representing the mean of the five surgeons' experience, indicates that 23 cases and 53 cases are required to achieve success rates of 90% and 95%, respectively. The initial reports regarding lymphatic mapping combined with this experience of 700 cases confirm the presence of a significant learning curve. Although this procedure may have an inherent failure rate, it is important to identify those factors that are under the control of the surgeon and, therefore, subject to improvement. We believe that these data provide surgeons performing lymphatic mapping and SLN biopsy with a new paradigm for assessing their skill and adequacy of training.

Primary Vascular Access for Chronic Hemodialysis: A Comparison of Arteriovenous Fistulae with PTFE Grafts

The purpose of this study was to compare patency rates of arteriovenous fistula (AVF) and polytetrafluoroethylene grafts (PTFE) for hemodialysis and the complications associated with each. All new permanent vascular access procedures for hemodialysis performed at one institution between January 1989 and December 1993 were reviewed with follow-up to December 1995. Patient demographics, secondary operations, complications, and length of stay were compared between the two types of access strategies. Seventy-seven PTFE and 89 AVF were performed in 166 patients. Age, sex, and frequency of diabetes were similar between the two groups. Primary patency rate at 36 months for AVF was 53%, compared with 16% for PTFE (p&lt;0.01). Secondary patency rate at 36 months was 70% for AVF and 50% for PTFE (p&lt;0.02). PTFE was associated with more hospital days per patient per year (26 vs 6.9), more infections (12 vs one during secondary patency interval), and a higher initial failure rate (19 vs eight) as compared with AVE. Patient survival rate at 4 years was higher for those with AVF (65% vs 52%). We conclude that an AVF as the primary access procedure for new renal dialysis patients is preferable to PTFE whenever possible.

Efficacy of balloon angioplasty of the superficial femoral artery and popliteal artery in the relief of leg ischemia

To assess the efficacy of balloon angioplasty in the superficial femoral artery (SFA) and popliteal artery for relief of lower-limb claudication and critical ischemia. All patients who underwent SFA or popliteal balloon angioplasty at the Royal Adelaide Hospital between January 1989 and September 1994 were reviewed. Risk factors, indications, angiographic variables, and complications were assessed. Outcome was expressed in life-table form as patency, limb survival, and patient survival rates. One hundred seventy-six patients (96 men, 80 women) who underwent 200 balloon angioplasty procedures were monitored for a mean of 25 months. Seventy-four percent of procedures were for claudication relief and 26% for critical ischemia. The cumulative patency rate at 24 months for all cases was 46%. The limb salvage rate was 95%, and the patient survival rate was 91% at 24 months. Percutaneous transluminal angioplasty of the SFA and popliteal arteries is commonly used to treat claudication and critical ischemia but is associated with a high initial failure rate and poor patency at 24 months. Balloon angioplasty is not recommended to treat claudication.

Anesthetic and obstetric outcome in morbidly obese parturients.

Large studies reporting anesthetic outcome for morbidly obese parturients are lacking. This study compares the anesthetic and obstetric outcome in morbidly obese parturients and matched control parturients. Anesthesia records were prospectively collected for all patients delivering between September 1978 and November 1989 whose weight exceeded 136.4 kg (300 pounds) at the time of delivery. A retrospective control patient group was collected by matching the first patient weighing less than 136.4 kg, delivered in the same month by the same obstertrician, to the corresponding morbidly obese parturient. Anesthetic and obstetric outcome variables were extracted from medical records and analyzed. Sixty-two percent of 117 morbidly obese women underwent cesarean section, while only 24% of control patients delivered abdominally (P < 0.05). Forty-eight percent of all laboring morbidly obese parturients required emergency cesarean section, compared with 9% of control laboring parturients (P < 0.05). Epidural anesthesia was used successfully for labor and cesarean delivery in 74 of 79 morbidly obese women and 66 of 67 control patients. When compared with control patients, initial epidural anesthesia failure was significantly more likely in morbidly obese women, requiring epidural catheter replacement. Difficult tracheal intubation occurred in 6 of 17 morbidly obese women, compared with 0 of 8 control women (P = 0.06). Morbidly obese women had increased incidences of antepartum medical disease, prolonged cesarean section operation times, serious postoperative complications, and increased hospital stays. The high incidences of antepartum medical disease and emergency cesarean section complicate anesthetic care in the morbidly obese parturients. Epidural anesthesia is feasible; however, the high initial failure rate necessitates early catheter placement, critical block assessment and catheter replacement when indicated, and provision for alternative airway management.