Traditional Sling Research Articles

Finite-time soft landing on asteroids using nonsingular terminal sliding mode control

Successful future asteroid landing missions require that the control method provides advanced disturbance rejection performance and strong robustness against parameter uncertainties to give higher accuracy and reliability in the complex space environment. Motivated by the requirement for safe and precise soft landing on asteroids, the finite-time soft-landing problem of an asteroid probe is addressed in this paper via a nonsingular terminal sliding mode (NTSM) control technique. The problem is formulated as a two-point boundary-value constraints control problem, where the initial and terminal requirements of the soft-landing problem are all included in the problem formulations. Then, according to the specific characteristics of the problem, an NTSM control law for soft landing on an asteroid is proposed. Simulation results demonstrate that, compared to the widely used traditional sling mode control method, the proposed method provides a much faster convergence rate, higher accuracies, better disturbance rejection properties and stronger robustness against parameter uncertainties.

Mini-bandelettes pour le traitement de l’incontinence urinaire d’effort féminine : revue de la littérature

To conduct a review about the use of single incision mini-slings (SIMS) to manage non-neurogenic stress urinary incontinence in women. Literature search in Pubmed/MEdline database until june 2013. TVT-Secur™ was excluded because this device is not anymore marketed. Ajust™ and Mini-Arc™ were the two main SIMS evaluated in the literature. Studies about Mini-Arc™ generated heterogeneous results, with a success rate between 44% and 91% after 1 year. Ajust™ was the most promising device with 80% efficacy after mid-term follow-up. All evaluated SIMS had a low rate of immediate complications. Two randomized controlled trials comparing SIMS and traditional mid-urethral slings were identified, as well as one meta-analysis; they all concluded to non-superiority or inferiority for the mini-sling versus traditional slings. Due to short follow-up, limited evidence and heterogeneous data, SIMS are not yet standard of care and further research is warranted.

Anatomic Bankart Repair Compared With Nonoperative Treatment and/or Arthroscopic Lavage for First-Time Traumatic Shoulder Dislocation

The objective of this systematic review was to determine the efficacy of anatomic Bankart repair in patients with a first-time shoulder dislocation compared with either arthroscopic lavage or traditional sling immobilization. We searched the Cochrane Central Register of Controlled Trials, Medline, Embase, CINAHL, Web of Science, LILACS, and a clinical trials registry for ongoing and completed randomized or quasi-randomized controlled trials comparing anatomic Bankart repair with either rehabilitation or arthroscopic lavage. Two reviewers selected studies for inclusion, assessed methodologic quality, and extracted data. Pooled analyses were performed by use of a random-effects model, and risk ratio (RR) and 95% confidence intervals (CIs) were computed. We included 3 randomized trials and 1 quasi-randomized trial comprising 228 patients. Of the included trials, 2 compared anatomic Bankart repair with sling immobilization whereas 2 compared Bankart repair with arthroscopic lavage. A meta-analysis of all 4 trials showed that the rate of recurrent instability was significantly lower among participants undergoing anatomic Bankart repair compared with those undergoing either immobilization or arthroscopic lavage (RR, 0.18; 95% CI, 0.10 to 0.33). Subgroup analysis showed that this effect persisted when Bankart repair was compared with arthroscopic lavage alone (2 studies) (RR, 0.14; 95% CI, 0.06 to 0.31) or sling immobilization alone (2 studies) (RR, 0.26; 95% CI, 0.10 to 0.67). Western Ontario Shoulder Instability scores were better with anatomic Bankart repair compared with either arthroscopic lavage or immobilization (2 studies) (mean difference, -232; 95% CI, -317 to -146). There is evidence to suggest treatment of young patients with a first-time shoulder dislocation with anatomic Bankart repair with the goal of lowering the rate of recurrent instability over the long-term and improving short-term quality of life. Level II, systematic review of Level I and II studies.

Retropubic and Transobturator Slings: Still Useful or Should All Patients Be Treated with Mini-slings?

Traditional retropubic and transobturator midurethral slings are reliable, safe, and effective treatments for stress urinary incontinence. Unfortunately, they also are associated with rare but severe complications, such as bladder or bowel perforation, vascular injury, nerve damage, and/or groin muscle pain that can occur with the blind passage of trocars. To maintain efficacy and patient satisfaction while avoiding such complications, minimally invasive mini-slings have been developed. These smaller mini-slings can be placed through a single vaginal incision at the level of the midurethra without trocars. Mini-slings often are performed as an outpatient surgery, with minimal morbidity, pain, and quick patient recovery. With continued refinement and surgeon experience, mini-slings potentially may be performed safely in the office setting under local anesthesia while maintaining the efficacy of traditional slings.

Position and Duration of Immobilization After Primary Anterior Shoulder Dislocation

Immobilization after closed reduction has long been the standard treatment for primary anterior dislocation of the shoulder. To determine the optimum duration and position of immobilization to prevent recurrent dislocation, a systematic review of the relevant literature was conducted. Of 2083 published studies that were identified by means of a literature review, nine Level-I and Level-II studies were systematically reviewed. The outcome of interest was recurrent dislocation. Additional calculations were performed by pooling data to identify the ideal length and position (external or internal rotation) of immobilization. Six studies (including five Level-I studies and one Level-II study) evaluated the use of immobilization in internal rotation for varying lengths of time. Pooled data analysis of patients younger than thirty years old demonstrated that the rate of recurrent instability was 41% (forty of ninety-seven) in patients who had been immobilized for one week or less and 37% (thirty-four of ninety-three) in patients who had been immobilized for three weeks or longer (p = 0.52). An age of less than thirty years at the time of the index dislocation was significantly predictive of recurrence in most studies. Three studies (including one Level-I and two Level-II studies) compared recurrence rates with immobilization in external and internal rotation. Analysis of the pooled data demonstrated that the rate of recurrence was 40% (twenty-five of sixty-three) for patients managed with conventional sling immobilization in internal rotation and 25% (twenty-two of eighty-eight) for those managed with bracing in external rotation (p = 0.07). Analysis of the best available evidence indicates there is no benefit of conventional sling immobilization for longer than one week for the treatment of primary anterior shoulder dislocation in younger patients. An age of less than thirty years at the time of injury is significantly predictive of recurrence. Bracing in external rotation may provide a clinically important benefit over traditional sling immobilization, but the difference in recurrence rates did not achieve significance with the numbers available.

Pelvic haematoma following Miniarc surgery - A case report

[Extract]The transobturator approach for midurethral sling placement in the treatment of stress urinary incontinence was introduced in 2001. Traditional transobturator sling procedures like TVT-O, Monarc, involve blind passage of instruments through obturator foramen, adductor muscles etc. This carries a finite risk of neurovascular injuries and postoperative groin pain. The newer generation of micro invasive slings such as the Miniarc may minimise these risks by avoiding needle passages through the obturator foramen and muscles. We report a case of postoperative pelvic haematoma, developed after a Miniarc operation.

Urodynamic changes after tension-free sling procedures: Mycromesh-Plus® vs TVT sling®

Assortments of suburethral sling procedures have become increasingly important in the treatment of stress urinary incontinence (SUI). This study compared a consecutive series of patients undergoing two types of no-tension, midurethral sling procedures: a traditional pubovaginal technique and graft (modified polytetrafluoroethylene graft; Mycromesh-Plus [MMP]) and the more recently introduced tension-free vaginal tape (TVT) sling. We observed for differences in success rates, urodynamic parameters, and complications of the two procedures. One group received a MMP sling, which was placed at the midurethra without tension. The other group underwent a minimally invasive TVT sling. Multichannel urodynamic studies were performed pre- and postoperatively. Cure rates for SUI were similar for the two groups (95 vs 95%). Urgency and urge incontinence symptoms improved substantially in both groups. Comparison of pre- and postoperative urodynamic indices demonstrated no differences in changes in average functional urethral lengths, changes in maximum urethral closure pressures, or improvement in pressure transmission ratios. Both groups showed a decrease in urethral mobility postoperatively. However, the TVT group demonstrated a lesser degree of change. While the TVT group did spontaneously void earlier than the MMP group (5.7 vs 9.7 days, p < 0.05), this did not result in significantly different postvoid residual volumes (71 vs 101 mL). Complications, including need for self-catheterization and sling revision or removal, and urinary tract infections also were fewer in the TVT group. This study demonstrated that the TVT sling affords an equivalent cure of SUI with similar urodynamic changes but significantly fewer complications than the more traditional MMP sling.

Is there still a place for the pubovaginal sling at the bladder neck in the era of the midurethral sling?

Perhaps the most significant advance in the modern-day surgical management of stress urinary incontinence is the introduction of the tension-free midurethral sling procedures. Based on a theory of anatomy and function, which emphasizes the importance of the midurethra in maintaining continence during stress, these minimally invasive procedures are being used widely in the surgical treatment of stress urinary incontinence. As surgeons continue to experience excellent early results, a major concern is defining the role of the traditional pubovaginal sling placed at the bladder neck. In addition to the obvious indications to consider a more traditional sling procedure (markedly atrophic vaginal wall or situations that may promote sling erosion), are there other clinical scenarios in which there still is a role for the traditional pubovaginal sling? Several clinical conditions that warrant consideration of a traditional sling procedure are presented in this review. Based on the mechanism of action and clinical data demonstrating decreased efficacy of midurethral sling procedures, we propose that a traditional pubovaginal sling be considered in the following clinical conditions: lack of urethral mobility, mixed urinary incontinence, concomitant urethral reconstruction, and after a failed sling procedure. In the absence of randomized control trials, we present evidence that makes a case for consideration of the traditional sling procedure in these complex clinical conditions.

Is there still a place for the pubovaginal sling at the bladder neck in the era of the midurethral sling?

Perhaps the most significant advance in the modern-day surgical management of stress urinary incontinence is the introduction of the tension-free midurethral sling procedures. Based on a theory of anatomy and function, which emphasizes the importance of the midurethra in maintaining continence during stress, these minimally invasive procedures are being used widely in the surgical treatment of stress urinary incontinence. As surgeons continue to experience excellent early results, a major concern is defining the role of the traditional pubovaginal sling placed at the bladder neck. In addition to the obvious indications to consider a more traditional sling procedure (markedly atrophic vaginal wall or situations that may promote sling erosion), are there other clinical scenarios in which there still is a role for the traditional pubovaginal sling? Several clinical conditions that warrant consideration of a traditional sling procedure are presented in this review. Based on the mechanism of action and clinical data demonstrating decreased efficacy of midurethral sling procedures, we propose that a traditional pubovaginal sling be considered in the following clinical conditions: lack of urethral mobility, mixed urinary incontinence, concomitant urethral reconstruction, and after a failed sling procedure. In the absence of randomized control trials, we present evidence that makes a case for consideration of the traditional sling procedure in these complex clinical conditions.

Cost effectiveness of tension-free vaginal tape for the surgical management of female stress incontinence

Stress urinary incontinence affects between 10 percent and 50 percent of women. Surgery is commonly recommended for troublesome incontinence that does not respond to nonsurgical management. Tension-free vaginal tape (TVT) is a newer, minimal access surgical sling procedure, which is being increasingly adopted worldwide. The cost-effectiveness of TVT in comparison with other surgical procedures, particularly open colposuspension, is assessed. Effectiveness estimates came from a systematic review of TVT compared with other surgical procedures (open and laparoscopic colposuspension, traditional slings, and injectables). Deterministic and probabilistic analyses were used to assess the likelihood of TVT being cost-effective. Sensitivity analyses assessed the impact of changing assumptions about cure rates and costs for TVT, cure rates for retreatment open colposuspension, and proportions of women who choose retreatment. Reliable estimates of relative effectiveness were difficult to derive because the few randomized controlled comparisons had not been optimally analyzed or fully reported. Results of the economic model suggested that TVT dominates open colposuspension (lower cost and same quality of life years [QALYs]) within 5 years after surgery. Stochastic analysis indicated that the likelihood of TVT being cost-effective was 100 percent if decision-makers are unwilling to pay for additional QALYs. TVT's dominance depended on the assumption fact that retreatment open colposuspension has lower cure rates than a first colposuspension. Analysis based on current short-term data indicates dominance of TVT over open colposuspension from approximately 5 years. There is a need for longer-term follow-up data from methodologically rigorous randomized trials to provide a sounder basis for estimating the relative benefits and cost implications.

Tension-free vaginal tape failure caused by sling displacement and successfully retreated using Burch colposuspension.

In 1995 Ulmsten and Petros first described the tension-free vaginal tape (TVT) procedure as a minimally invasive treatment of genuine stress incontinence (GSI). It restores the pubourethral ligament and subvaginal hammock and has cure rates comparable to retropubic urethropexy. While the success rate is comparable to traditional sling procedures it requires a hospital stay of less than 24 h. The causes of failure of this procedure have not been reported in the literature. We report a case of recurrent GSI after TVT that was then successfully treated by colposuspension. The cause of the failure is also discussed. (excerpt)

Effect of Tension-Free Vaginal Tape Procedure on Urodynamic Continence Indices

In Brief OBJECTIVE To assess the difference in measured urethral function before and after tension-free vaginal tape procedure (TVT). METHODS Women who underwent TVT for genuine stress incontinence with or without intrinsic sphincter deficiency completed this study. Multichannel urodynamic testing was performed preoperatively and 6 weeks postoperatively. Maximum urethral closure pressure and pressure transmission ratio were recorded. Valsalva leak point pressures were determined at 150 mL and at full bladder capacity. Resting and straining urethral angles were measured using the cotton swab technique. Subjects completed both the Incontinence Impact Questionnaire and Urodynamic Distress Inventory preoperatively and postoperatively. RESULTS Thirty-five consecutive women were studied. Twenty-three (65.7%) had a preoperative diagnosis of intrinsic sphincter deficiency as defined by maximum urethral closure pressure less than 20 cm H2O and/or Valsalva leak point pressure less than 60 cm H2O. Subjective and objective success rates were 91% and 83%, respectively. Subjects showed an 86.8% (95% CI 71.9%, 100.0%) improvement in their Incontinence Impact Questionnaire score and a 72.9% (95% CI 62.6%, 83.1%) improvement in their Urodynamic Distress Inventory score. The mean change in maximum urethral closure pressure was −1.3 cm H2O (95% CI −5.9, 3.3), whereas the pressure transmission ratio increased 15.7% (95% CI 5.0%, 26.3%). The mean decrease in straining urethral angle was 16.3° (95% CI −23.9°, −8.7°). Cured subjects demonstrating hypermobility preoperatively continued to do so postoperatively. CONCLUSION There was a significant increase in pressure transmission ratio, but not maximum urethral closure pressure, after TVT. These changes are similar to those reported after retropubic urethropexy and traditional sling procedures. The effectiveness of the TVT sling does not appear to depend on a clinically significant change in the straining urethral angle. The tension-free vaginal tape procedure results in an increase in pressure transmission to the urethra without correcting urethral hypermobility.

Effect of tension-free vaginal tape procedure on urodynamic continence indices

OBJECTIVE: To assess the difference in measured urethral function before and after tension-free vaginal tape procedure (TVT). METHODS: Women who underwent TVT for genuine stress incontinence with or without intrinsic sphincter deficiency completed this study. Multichannel urodynamic testing was performed preoperatively and 6 weeks postoperatively. Maximum urethral closure pressure and pressure transmission ratio were recorded. Valsalva leak point pressures were determined at 150 mL and at full bladder capacity. Resting and straining urethral angles were measured using the cotton swab technique. Subjects completed both the Incontinence Impact Questionnaire and Urodynamic Distress Inventory preoperatively and postoperatively. RESULTS: Thirty-five consecutive women were studied. Twenty-three (65.7%) had a preoperative diagnosis of intrinsic sphincter deficiency as defined by maximum urethral closure pressure less than 20 cm H 2O and/or Valsalva leak point pressure less than 60 cm H 2O. Subjective and objective success rates were 91% and 83%, respectively. Subjects showed an 86.8% (95% CI 71.9%, 100.0%) improvement in their Incontinence Impact Questionnaire score and a 72.9% (95% CI 62.6%, 83.1%) improvement in their Urodynamic Distress Inventory score. The mean change in maximum urethral closure pressure was −1.3 cm H 2O (95% CI −5.9, 3.3), whereas the pressure transmission ratio increased 15.7% (95% CI 5.0%, 26.3%). The mean decrease in straining urethral angle was 16.3° (95% CI −23.9°, −8.7°). Cured subjects demonstrating hypermobility preoperatively continued to do so postoperatively. CONCLUSION: There was a significant increase in pressure transmission ratio, but not maximum urethral closure pressure, after TVT. These changes are similar to those reported after retropubic urethropexy and traditional sling procedures. The effectiveness of the TVT sling does not appear to depend on a clinically significant change in the straining urethral angle.

IS MODIFIED IN SITU VAGINAL WALL SLING OPERATION THE TREATMENT OF CHOICE FOR RECURRENT GENUINE STRESS INCONTINENCE?

We evaluate objectively the results of a modified in situ vaginal wall sling operation for recurrent genuine stress incontinence and whether it is a substitute for the traditional sling procedure. A total of 23 patients with urodynamically proved recurrent genuine stress urinary incontinence were recruited in this study. Patients were treated with a modified needle urethropexy technique using an island of in situ vaginal skin as a sling to support the bladder neck and urethra. Surgical outcome was evaluated subjectively and objectively at a median of 15 months. A total of 42 patients who underwent a traditional polytetrafluoroethylene sling operation served as controls. The cure rate of the vaginal wall sling operation was 34.8% by objective assessment, which was lower than that of the traditional sling procedure (88.1%, p <0.05). The subjective success rate demonstrated the same results (vaginal sling 60.9% versus traditional sling 92.9%, p <0.05). The risk factors for operation failure were lower maximal urethral pressure, lower urethral closing pressure, narrow vaginal capacity and previous anterior colporrhaphy or a Stamey operation (all p <0.05). In 3 cases suburethral epithelial inclusion cysts were specific complications of the operation. There was no prolonged urinary retention or urethral erosion. Based on our results, we do not believe that the vaginal wall sling operation should be recommended for all recurrent genuine stress urinary incontinence cases and especially not for those with factors predictive of surgical failure. Further studies are needed to investigate and clarify the possible causes of failure.

Single puncture laparoscopic sling procedure

The sling procedure has become the procedure of choice for women with recurrent stress incontinence with a poorly mobile, fibrotic urethra and for women with primary incontinence and very low urethral closure pressures consistent with inadequate intrinsic urethral tone. In addition to the increased risk of graft infection or postoperative rejection associated with the use of synthetic materials, the technical drawback of traditional sling procedures is that the placement of the graft through the space of Retzius is carried out blindly, increasing the risk of bladder and urethral injury, hemorrhage, infection and nerve trauma. We had the opportunity to perform the first successful laparoscopic sling procedure using a single puncture technique in a 43 year-old woman at the time of laparoscopic hysterectomy for large symptomatic leiomyomata. In addition to her gynecologic problem, the patient had very low proximal urethral pressure. The procedure was performed under direct laparoscopic view, avoiding the blind placement of the sling under the proximal urethra and bladder neck and avoiding injury to the bladder and urethra. The procedure was almost bloodless. The patient was discharged 24 hours postoperatively. The Foley catheter was removed on the third postoperative day. No voiding difficulties occurred. Her postoperative course was uneventful. Postoperative evaluation 6 months after surgery demonstrated normal urethral closure pressure, urinary continence, and absence of reaction to the sling graft material. This singular experience appears to demonstrate that laparoscopy may play an important role in improving the surgical performance and outcome of the sling procedure.

Correction of recurrent stress urinary incontinence by needle urethropexy with a vaginal wall sling.

To review the results of a modification of the transvaginal needle urethropexy as a treatment for patients developing recurrence after surgical correction of stress urinary incontinence (SUI). Twelve women who had undergone previous surgery for SUI and had developed recurrence of the symptoms were treated by a needle urethropexy technique which employed an island of in situ vaginal skin as a sling to support the bladder neck and urethra. After a mean follow-up of 17.3 months, eight of the patients obtained excellent results, three experienced improvement and one was a failure. The vaginal wall sling needle urethropexy was a simple technique to perform and carries a low morbidity. The results are similar to those of the more elaborate traditional sling procedures reported in the literature.