Operative Standardisierung bei randomisiert kontrollierten Studien in der Chirurgie

Continuous versus interrupted skin sutures for non-obstetric surgery

BACKGROUND

Most surgical procedures involve a cut in the skin, allowing the surgeon to gain access to the surgical site. Most surgical wounds are closed fully at the end of the procedure; this review focuses on these closed wounds. There are many ways to close the surgical incision, for example, using sutures (stitches), staples, tissue adhesives or tapes. Skin sutures can be continuous or interrupted. In general, continuous sutures are usually subcuticular and can be absorbable or non-absorbable, while interrupted sutures are usually non-absorbable and involve the full thickness of the skin - although some surgeons do use absorbable interrupted sutures.

OBJECTIVES

To compare the benefits and harms of continuous compared with interrupted skin closure techniques in participants undergoing non-obstetric surgery.

SEARCH METHODS

In August 2013 we searched the following databases: Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid Embase; and EBSCO CINAHL.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) that compared skin closure using continuous sutures with skin closure using interrupted sutures, irrespective of whether there were differences in the nature of the suture materials used in the two groups. We included all relevant RCTs in the analysis, irrespective of language of publication, publication status, publication year or sample size.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified the trials and extracted data. We calculated the risk ratio (RR) with 95% confidence intervals (CI) for comparing binary outcomes between the groups, and calculated the mean difference (MD) with 95% CI for comparing continuous outcomes. We performed meta-analysis using a fixed-effect model and a random-effects model. We performed intention-to-treat analysis whenever possible.

MAIN RESULTS

We included five RCTs with a total of 827 participants. Outcomes were available for 730 participants (384 participants randomised to continuous sutures and 346 participants to interrupted sutures). All the trials were of unclear or high risk of bias. The participants underwent abdominal or groin operations. The only outcomes reported in the trials were superficial surgical site infection, superficial wound dehiscence (breakdown) and length of hospital stay. Other important outcomes such as quality of life, long-term patient outcomes and use of healthcare resources were not reported in these trials.Overall, 6.5% (39/602 participants, four trials) developed superficial surgical site infections. There was no significant difference between the groups in the proportion of participants who developed superficial surgical site infections (RR 0.73; 95% CI 0.40 to 1.33). A total of 23 participants (23/625 (3.7%), four trials) developed superficial wound dehiscence. Twenty-two of the 23 participants belonged to the interrupted suture group.The proportion of participants who developed superficial wound dehiscence was statistically significantly lower in the continuous suture group compared to the interrupted suture group (RR 0.08; 95% CI 0.02 to 0.35). Most of these wound dehiscences were reported in two recent trials in which the continuous skin suture groups received absorbable subcuticular sutures while the interrupted skin suture groups received non-absorbable transcutaneous sutures. The non-absorbable sutures were removed seven to nine days after surgery in the interrupted sutures groups whilst sutures in the comparator groups were not removed, being absorbable. The continuous suture technique with absorbable suture does not require suture removal and provides support for the wound for a longer period of time. This may have contributed to the difference between the two groups in the proportion of participants who developed superficial wound dehiscence. There was no significant difference in the length of the hospital stay between the two groups (MD -1.40 days; 95% CI -7.14 to 4.34).

AUTHORS' CONCLUSIONS

Superficial wound dehiscence may be reduced by using continuous subcuticular sutures. However, there is uncertainty about this because of the quality of the evidence. Besides, the nature of the suture material used may have led to this observation, as the continuous suturing technique used suture material that did not need to be removed, whereas the comparator used interrupted (non-absorbable) sutures that did need to be removed. Differences in the methods of skin closure have the potential to affect patient outcomes and use of healthcare resources. Further well-designed trials at low risk of bias are necessary to determine which type of suturing is better.

[Barriers to clinical studies involving medical devices]

Clinical trials with medical devices need to be considered in terms of the complexity of surgical procedures. Creating the proper environment for the conduct of trials includes improved academic career opportunities in the field of clinical research, methodological competence, and established structures. The challenges and pitfalls in the design of clinical trials involving medical devices are based on aspects such as blinding, placebo, learning curves and surgeons' expertise. Surgical procedures should be standardised, and a study hypothesis needs to be established which is answerable by a relevant and feasible sample size. Besides the above-mentioned challenges, efficient interactions between authorities, universities, hospitals, and medical device manufacturers are mandatory to allow for quality and relevance of clinical studies in this field.

Current practice of abdominal wall closure in elective surgery - Is there any consensus?

BACKGROUND

Development of incisional hernia after open abdominal surgery remains a major cause of post-operative morbidity. The aim of this study was to determine the current practice of surgeons in terms of access to and closure of the abdominal cavity in elective open surgery.

METHODS

Twelve surgical departments of the INSECT-Trial group documented the following variables for 50 consecutive patients undergoing abdominal surgery: fascial closure techniques, applied suture materials, application of subcutaneous sutures, subcutaneous drains, methods for skin closure. Descriptive analysis was performed and consensus of treatment variables was categorized into four levels: Strong consensus >95%, consensus 75-95%, overall agreement 50-75%, no consensus <50%.

RESULTS

157 out of 599 patients were eligible for analysis (85 (54%) midline, 54 (35%) transverse incisions). After midline incisions the fascia was closed continuously in 55 patients (65%), using slowly absorbable (n = 47, 55%), braided (n = 32, 38%) sutures with a strength of 1 (n = 48, 57%). In the transverse setting the fascia was closed continuously in 39 patients (72%) with slowly absorbable (n = 22, 41%) braided sutures (n = 27, 50%) with a strength of 1 (n = 30, 56%).

CONCLUSION

In the present evaluation midline incision was the most frequently applied access in elective open abdominal surgery. None of the treatments for abdominal wall closure (except skin closure in the midline group) is performed on a consensus level.

DISPACT trial: a randomized controlled trial to compare two different surgical techniques of DIStal PAnCreaTectomy - study rationale and design

BACKGROUND

Surgery is of increasing importance in the treatment and outcome of diseases of the pancreas worldwide. The incidence of pancreatic cancer (7-11/ 100,000 per year) has risen over the last years and surgical resection remains the only option for definite cure. Twenty-five percent of all resections are left of the superior mesenteric vein (distal pancreatectomy) and the appropriate closure technique for the pancreatic remnant remains unclear. Pancreatic fistulas are the most common (0-40%) and relevant postoperative complication. The optimal surgical strategy for pancreatic resection needs to be identified from the large number of surgical procedures available today.

PURPOSE

To evaluate the effectiveness of the two most common surgical techniques for distal pancreatectomy: stapler versus hand-sewn closure of the pancreatic remnant.

METHODS

In order to account for the uncertainty and clinical heterogeneity in the management of the pancreatic remnant following distal pancreatectomy, a study protocol is developed on the basis of a retrospective survey of patients in a center of excellence for pancreatic surgery and a systematic review with meta-analysis.

RESULTS

The DISPACT trial is a multicentered, randomized, controlled and patient-and observer-blinded trial using a two-group parallel group-sequential superiority design to compare the two techniques mentioned above. It will include approximately 336 randomized patients at up to 20 centers of excellence in pancreatic surgery, who are undergoing elective distal pancreatectomy for resectable benign, malign, and neuroendocrine tumors, chronic pancreatitis and pseudocysts of the pancreatic body and tail. The combination of the rate of postoperative pancreatic fistula and mortality will be evaluated as the primary endpoint. In addition, a set of general and surgical parameters will be analyzed. Pre-specified treatment manuals and continuous intra-operative (photo-documentation of surgical procedures and blinded evaluation thereafter) and on-site monitoring will assure that the treatment of the study patients conforms to protocol and will minimize clinical heterogeneity. Due to uncertainties about the effect sizes of the primary endpoint, an a priori planned interim analysis of the primary endpoint will be conducted after 224 evaluable patients are selected in order to reassess the initially planned sample size.

LIMITATIONS

Since pre-existing evidence was limited our initial sample size calculation is based on uncertain assumptions and may need to be modified in a planned interim analysis. Moreover, since surgical experience remains a potential confounder in surgical trials, learning curve bias has to be taken into account when analyzing the results. Given the participating trial sites, standardization of peri-and postoperative treatment represents a major issue of trial conduct.

CONCLUSIONS

A group-sequential study design accounts for the uncertainty of pre-existing evidence. Also, standardization of surgical and postoperative care and blinded outcome assessment as well as adjustment for varying surgical expertise will contribute to a high validity and generalizability of the results.

Primary mesh augmentation with fibrin glue for abdominal wall closure--investigations on a biomechanical model

BACKGROUND

The occurrence of incisional hernias after various types of abdominal procedures and incisions continues to be a problem. A number of studies conducted for diverse risk groups have identified a beneficial role for the prophylactic use of mesh augmentation. To what extent this affects the stability of a suture was tested in our biomechanical model.

MATERIALS AND METHODS

To that effect, we compared three groups, carrying out six measurements in each case: (1) single suture in a muscle specimen, (2) suture and additional reinforcement with fibrin glue, and (3) suture and additional reinforcement with a mesh fixed with fibrin glue (Tissucol, Tisseel; with an overlap of 2 cm to all sides).

RESULTS

The single suture conferred a tensile strength, which in our model, was just above the prescribed maximum abdominal pressure of 32 N (37.3 N). The additional use of fibrin glue did not have any significant impact on this result (41.8 N). Only through mesh augmentation with fibrin glue was it possible to achieve a significantly greater tensile strength (64.5 N, p = 0.003).

CONCLUSIONS

The prophylactic use of meshes for stabilization of laparotomy closures appears to be effective. Adequate mesh fixation can be achieved with fibrin glue alone. Further experimental studies and in particular randomized clinical trials are needed to demonstrate proof of the long-term advantages of mesh augmentation in risk groups.

Four years of teaching principles in clinical trials--a continuous evaluation of the postgraduate workshop for surgical investigators at the study center of the German Surgical Society

INTRODUCTION

Only a small part of the daily work in the field of surgery is based on high-level evidence. To improve the rate of evidence-based medicine (EBM) in surgery, more surgical, randomized controlled trials have been advocated. In addition, it has been recognized that educational issues that concern methods and techniques of clinical research are of similar importance. Therefore, a clinical investigator course focusing particularly on the issues of surgical trials was initiated in 2005. The structure of this course is demonstrated here as well as the results of its evaluation over the last 4 years.

MATERIAL AND METHODS

All participants were invited to rate both the lecture and the teachers with the help of a standardized evaluation questionnaires (rating scale from 1 = excellent to 6 = insufficient). Lectures were evaluated via questions on content, comprehension, and learning effect. Teachers were evaluated in terms of rhetorical abilities, content, and presentation technique, respectively. Assessment of personal long-term learning effects was evaluated by an e-mail survey.

RESULTS

Seventy-three participants were trained in a total of 4 courses. Participants in each course completed the evaluation questionnaires. In 2005, 20 of 21 (95.2%) participants completed the questionnaire; in 2006, 11 of 11 participants completed it (100%); in 2007, 19 of 22 (86.4%) participants completed it; and in 2008, 16 of 19 (84.2%) participants completed it. The overall evaluation of the course was graded 1.52 for content and 1.72 for clarity, and the learning effect was assessed at 1.60. The 16 lecturers came from different institutions involved in clinical research and evidence-based surgery. Besides classic lecturing, the current assembly of the course consists of 6 lectures designed as hands-on sessions. A survey (48.5% response rate) with a mean follow-up of 1.72 years (range, 6 months to 3 years) revealed that the enduring learning effect was rated 2.09, and 70.4% of former participants actually participated in randomized controlled trials.

CONCLUSIONS

The development of a clinical investigator course tailored to the needs of surgeons provides hospitals with a key tool for promoting surgical interest in clinical trials.

A historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety and efficacy of MonoMax suture material for abdominal wall closure after primary midline laparotomy. ISSAAC-Trial [NCT005725079]

BACKGROUND

Several randomized controlled trials have compared different suture materials and techniques for abdominal wall closure with respect to the incidence of incisional hernias after midline laparotomy and shown that it remains, irrespective of the methods used, considerably high, ranging from 9% to 20%. The development of improved suture materials which would reduce postoperative complications may help to lower its frequency.

DESIGN

This is a historically controlled, single-arm, multi-centre, prospective trial to evaluate the safety of MonoMax suture material for abdominal wall closure in 150 patients with primary elective midline incisions. INSECT patients who underwent abdominal closure using Monoplus and PDS will serve as historical control group. The incidences of wound infections and of burst abdomen are defined as composite primary endpoints. Secondary endpoints are the frequency of incisional hernias within one year after operation and safety. To ensure adequate comparability in surgical performance and recruitment, the 4 largest centres of the INSECT-Trial will participate. After hospital discharge, the investigators will examine the enrolled patients again at 30 days and at 12 +/- 1 months after surgery.

CONCLUSION

This historically controlled, single-arm, multi-centre, prospective ISSAAC trial aims to assess whether the use of an ultra-long-lasting absorbable monofilament suture material is safe and efficient.

TRIAL REGISTRATION

NCT005725079.