Interrupted or Continuous Slowly Absorbable Sutures For Closure of Primary Elective Midline Abdominal Incisions

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.

Incisional hernia rate 3 years after midline laparotomy

BACKGROUND

Incisional hernia is the most frequent long-term complication after visceral surgery, with an incidence of between 9 and 20 per cent 1 year after operation. Most controlled studies provide only short-term follow-up, and the actual incidence remains unclear. This study evaluated the incidence of incisional hernia up to 3 years after midline laparotomy in two prospective trials.

METHODS

Three-year follow-up data from the ISSAAC (prospective, multicentre, historically controlled) and INSECT (randomized, controlled, multicentre) trials focused on the rate of incisional hernia 1 and 3 years after surgery. Differences between the two groups were compared using t tests for continuous data and the χ2 test for categorical data.

RESULTS

Analysis of 775 patients included in the two trials suggested that the incisional hernia rate increased significantly from 12.6 per cent at 1 year to 22.4 per cent 3 years after surgery (P < 0.001), a relative increase of more than 60 per cent.

CONCLUSION

This follow-up of two trials demonstrated that 1 year of clinical follow-up for detection of incisional hernia is not sufficient; follow-up for at least 3 years should be mandatory in any study evaluating the rate of postoperative incisional hernia after midline laparotomy.

[Operative therapy of secondary ventral hernia: technical principles]

Secondary ventral hernia or incisional hernia occurs in at least 20 % of cases after laparotomy and most patients are symptomatic. The pathogenesis of incisional hernia is believed to be based on a defect in collagen synthesis indicating the necessity of covering the whole original incision with a non-resorbable, macroporous mesh. These meshes can be used on top of the fascia (onlay), in a retromuscular fashion (sublay) or intraperitoneally (IPOM). The IPOM technique is the preferred procedure during laparoscopic repair of ventral hernias. The clear advantage of the laparoscopic approach is the dramatically reduced rate of wound complications, especially infections. Major defects of the abdominal wall require plastic reconstruction with the component separation technique in both anterior and posterior approaches. The component separation technique must be combined with retromuscular mesh augmentation enabling a recurrence rate of less than 10 % and an acceptable morbidity to be achieved.

Prevention of incisional hernias: how to close a midline incision

The development of wound complications is closely related to the surgical technique at wound closure. The risk of the suture technique affecting the development of wound dehiscence and incisional hernia can be monitored through the suture length to wound length ratio. Midline incisions should be closed in one layer by a continuous-suture technique using a monofilament suture material tied with self-locking knots. Excessive tension should not be placed on the suture. Closure must always be with a suture length to wound length ratio higher than 4.

A double blind randomized controlled trial comparing primary suture closure with mesh augmented closure to reduce incisional hernia incidence

Background

Incisional hernia is the most frequently seen long term complication after laparotomy causing much morbidity and even mortality. The overall incidence remains 11-20%, despite studies attempting to optimize closing techniques. Two patient groups, patients with abdominal aortic aneurysm and obese patients, have a risk for incisional hernia after laparotomy of more than 30%. These patients might benefit from mesh augmented midline closure as a means to reduce incisional hernia incidence.

Methods/design

The PRImary Mesh Closure of Abdominal Midline Wound (PRIMA) trial is a double-blinded international multicenter randomized controlled trial comparing running slowly absorbable suture closure with the same closure augmented with a sublay or onlay mesh. Primary endpoint will be incisional hernia incidence 2 years postoperatively. Secondary outcomes will be postoperative complications, pain, quality of life and cost effectiveness.

A total of 460 patients will be included in three arms of the study and randomized between running suture closure, onlay mesh closure or sublay mesh closure. Follow-up will be at 1, 3, 12 and 24 months with ultrasound imaging performed at 6 and 24 months to objectify the presence of incisional hernia. Patients, investigators and radiologists will be blinded throughout the whole follow up.

Disccusion

The use of prosthetic mesh has proven effective and safe in incisional hernia surgery however its use in a prophylactic manner has yet to be properly investigated. The PRIMA trial will provide level 1b evidence whether mesh augmented midline abdominal closure reduces incisional hernia incidence in high risk groups.

Trial registration

Clinical trial.gov NCT00761475.

Surgical-site infection after abdominal wall closure with triclosan-impregnated polydioxanone sutures: results of a randomized clinical pathway facilitated trial (NCT00998907)

BACKGROUND

Wound infections after abdominal surgery are still frequent types of nosocomial infections. Suture materials might serve as a vehicle for mechanical transport of bacteria into the surgical wound. To prevent the contamination of suture material in surgical wounds, triclosan-coated suture materials with antibacterial activity was developed. We here report a prospective randomized pathway controlled trial investigating the effect of triclosan impregnation of polydioxanone sutures used for abdominal wall closure on the rate of surgical-site infections.

PATIENTS AND METHODS

A total of 856 patients included in this trial underwent a standardized clinical pathway documented abdominal wall closure after abdominal surgery. Patients were randomized to have the fascia closed with either a 2-0 polydioxanone loop or a triclosan impregnated 2-0 polydioxanone loop. The primary outcome was the number of wound infections. Risk factors for poor wound healing were collected prospectively to compare the two groups.

RESULTS

When a PDS loop suture for abdominal wall closure was used, 42 (11.3%) patients with wound infections were detected. The number of patients with wound infections decreased significantly to 31 when the PDS plus for abdominal wall closure was used (6.4%, P < .05). Other risk factors for the development of side infections were comparably in the two groups.

CONCLUSION

This clinical pathway facilitated trial shows that triclosan impregnation of a 2-0 polydioxanone closing suture can decrease wound infections in patients having a laparotomy for general and abdominal vascular procedures.

[Results of a national survey on abdominal wall closure]

OBJECTIVE

To assess knowledge on the abdominal wall closure through a surgeon cohort survey.

METHODS

A twenty question individual questionnaire on laparotomy in elective surgery.

RESULTS

A total of 131 surgeons from seven hospitals responded (72% specialists and 28% in training). 71% of respondents estimated the frequency of incisional hernia to be higher than 15% and 54% considered the technique to be the most significant risk factor. 85% considered midline laparotomy closed with slow absorbable suture (57%) in a single layer (66%) to be the most appropriate technique. 67% believed retention sutures to be the appropriate prevention technique. 50% did not know or could not apply the 4:1 technique. 87% considered that an incisional hernia can be prevented and that the technique is the most important factor on which to act. 84% believed that a prosthesis can prevent the occurrence of incisional hernia, whereas 40% of respondents never use it and only 38% use it in patients at risk. On comparing surveys between specialists and residents, significant differences appeared in terms of a better understanding of the theoretical technical aspects in trainee surgeons.

CONCLUSIONS

Although the results show an adequate understanding of the epidemiology and risk factors for development of incisional hernia, training and consensus measures are likely to be introduced in some basic technical aspects in order to improve results in laparotomy closure.

Reversibility of abdominal wall atrophy and fibrosis after primary or mesh herniorrhaphy

OBJECTIVE

To determine whether primary or mesh herniorrhaphy reverses abdominal wall atrophy and fibrosis associated with hernia formation.

BACKGROUND

We previously demonstrated that hernia formation is associated with abdominal wall atrophy and fibrosis after 5 weeks in an animal model.

METHODS

A rat model of chronic incisional hernia was used. Groups consisted of uninjured control (UC, n = 8), sham repair (SR, n = 8), unrepaired hernia (UR, n = 8), and 2 repair groups: primary repair (PR, n = 8) or tension-free polypropylene mesh repair (MR, n = 8) hernia repair on postoperative day (POD) 35. All rats were killed on POD 70. Intact abdominal wall strips were cut perpendicular to the wound for tensiometric analysis. Internal oblique muscles were harvested for fiber type and size determination.

RESULTS

No hernia recurrences occurred after PR or MR. Unrepaired abdominal walls significantly demonstrated greater stiffness, increased breaking and tensile strengths, yield load and yield energy, a shift to increased type IIa muscle fibers than SR (15.9% vs 9.13%; P < 0.001), and smaller fiber cross-sectional area (CSA, 1792 vs 2669 μm(2); P < 0.001). PR failed to reverse any mechanical changes but partially restored type IIa fiber (12.9% vs 9.13% SR; P < 0.001 vs 15.9% UR; P < 0.01) and CSA (2354 vs 2669 μm(2) SR; P < 0.001 vs 1792 μm(2) UR; P < 0.001). Mesh-repaired abdominal walls demonstrated a trend toward an intermediate mechanical phenotype but fully restored type IIa muscle fiber (9.19% vs 9.13% SR; P > 0.05 vs 15.9% UR; P < 0.001) and nearly restored CSA (2530 vs 2669 μm(2) SR; P < 0.05 vs 1792 μm(2) UR; P < 0.001).

CONCLUSIONS

Mesh herniorrhaphy more completely reverses atrophic abdominal wall changes than primary herniorrhaphy, despite failing to restore normal anatomic muscle position. Techniques for hernia repair and mesh design should take into account abdominal wall muscle length and tension relationships and total abdominal wall compliance.

Extraction site location and incisional hernias after laparoscopic colorectal surgery: should we be avoiding the midline?

BACKGROUND

Laparoscopic colorectal procedures require specimen extraction. It is unclear whether extraction site affects the incidence of incisional hernia (IH).

METHODS

Patients undergoing laparoscopic colectomy over a 6-year period were identified. Outcomes were compared between patients to evaluate the incidence of hernia.

RESULTS

Among 480 laparoscopic colorectal procedures, extraction sites were midline (n = 305), muscle splitting (n = 128), Pfannenstiel (n = 26), and ostomy (n = 21). Average follow-up was 3.5 years. Age, gender, diagnosis, extraction incision length, and hospital stay were similar. The mean body mass index for all patients was 28 kg/m(2) and for those with IHs was 31 kg/m(2) (P = .008). The overall IH rate was 7%. Midline IHs accounted for 84% of all hernias, occurring in 8.9% of midline extractions (P < .05 vs nonmidline extractions). Hernia rates for muscle-splitting, Pfannenstiel, and ostomy site extractions were 2.3%, 3.8%, and 4.8%, respectively.

CONCLUSIONS

Although midline hernia rates were lower than traditionally reported with open surgery, midline extraction sites have a higher chance of IH than nonmidline sites.

HAnd Suture Versus STApling for Closure of Loop Ileostomy (HASTA Trial): results of a multicenter randomized trial (DRKS00000040)

OBJECTIVES

The objective of the HASTA trial was to compare hand suture versus stapling loop ileostomy closure in a randomized controlled trial.

BACKGROUND

Bowel obstruction is one of the main and the clinically and economically most relevant complication following closure of loop ileostomy after low anterior resection. The best surgical technique for closure of loop ileostomy has not been defined yet.

METHODS

HASTA trial is a multicenter pragmatic randomized controlled surgical trial with 2 parallel groups to compare hand suture versus stapling for closure of loop ileostomy. The primary endpoint was the rate of bowel obstruction within 30 days after ileostomy closure.

RESULTS

A total of 337 randomized patients undergoing closure of loop ileostomy after low anterior resection because of rectal cancer in 27 centers were included. The overall rate of postoperative ileus after ileostomy closure was 13.4%. Seventeen of 165 (10.3%) patients in the stapler group and 27 of 163 (16.6%) in the hand suture group developed bowel obstruction within 30 days postoperatively [odds ratio (OR) = 1.72; 95% confidence interval (CI): 0.89-3.31 = 0.10]. Duration of surgical intervention was significantly shorter in the stapler group (15 minutes; P < 0.001). Multivariable analysis of potential risk factors did not reveal any significant correlation with development of postoperative ileus. Rate of anastomotic leakage (stapler: 3.0%, hand suture: 1.8%, P = 0.48) did not differ significantly as well as all other secondary endpoints.

CONCLUSIONS

Hand-sewn anastomosis versus stapler ileo-ileostomy for ileostomy closure are equally effective in terms of postoperative bowel obstruction, with stapler anastomosis leading to a shorter operation time. Postoperative ileus after ileostomy reversal remains a relevant complication.

Triclosan-coated sutures reduce the incidence of wound infections and the costs after colorectal surgery: a randomized controlled trial

BACKGROUND

In colorectal surgeries, surgical site infections (SSIs) frequently cause morbidity; an incidence of up to 20% has been shown in previous studies. Recently, to prevent microbial colonization of suture material in operative wounds, triclosan-coated polyglactin suture materials with antimicrobial activity have been developed; however, their significance in colorectal surgery remains unclear. This randomized controlled trial was conducted to assess the value of triclosan-coated polyglactin sutures in colorectal surgery.

METHODS

A total of 410 consecutive patients who had undergone elective colorectal operations were enrolled in this trial. Of those patients, the 206 in the study group underwent wound closure with triclosan-coated polyglactin 910 antimicrobial sutures, and the 204 patients in the control group received conventional wound closures with polyglactin 910 sutures.

RESULTS

The study group and the control group were comparable regarding risk factors for SSIs. The incidence of wound infection in the study group was 9 of 206 patients (4.3%), and that in the control group was 19 of 204 patients (9.3%). The difference is statistically significant in the 2 groups (P = .047). The median additional cost of wound infection management was $2,310. The actual entire additional cost, therefore, of 9 patients in the study group was $18,370, and that of 19 patients in the control group was $60,814.

CONCLUSION

Triclosan-coated sutures can reduce the incidence of wound infections and the costs in colorectal surgery.

Closing midline abdominal incisions

BACKGROUND

The most important wound complications are surgical site infection, wound dehiscence and incisional hernia. Experimental and clinical evidences support that the development of wound complications is closely related to the surgical technique at wound closure.

RESULTS

The suture technique monitored through the suture length-to-wound length ratio is of major importance for the development of wound complications. The risk of wound dehiscence is low with a high ratio. The ratio must be higher than 4; otherwise, the risk of developing an incisional hernia is increased four times. With a ratio higher than 4, both the rate of wound infection and incisional hernia are significantly lower if closure is done with small stitches placed 5 to 8 mm from the wound edge than with larger stitches placed more than 10 mm from the wound edge.

CONCLUSIONS

Midline incisions should be closed in one layer by a continuous suture technique. A monofilament suture material should be used and be tied with self-locking knots. Excessive tension should not be placed on the suture. Wounds must always be closed with a suture length-to-wound length ratio higher than 4. The only way to ascertain this is to measure, calculate and document the ratio at every wound closure. A high ratio should be accomplished with many small stitches placed 5 to 8 mm from the wound edge at very short intervals.

Incidence and prevention of ventral incisional hernia

OBJECTIVE

Ventral incisional hernia is a common complication of abdominal surgery. The incidence ranges from 2% to 20% and varies greatly from one series to another. The goal of this study was to determine the incidence, risk factors, and preventive measures for ventral incisional hernia.

MATERIALS AND METHODS

An analysis of the surgical literature was performed using the search engines EMBASE, Cochrane Library, and PubMed with the keywords: abdominal hernia, wound dehiscence, incisional hernia, incidence, trocar site hernia, and hernia prevention.

RESULTS

The overall incidence of incisional hernia after laparotomy was 9.9%. The incidence was significantly higher for midline incisions compared with transverse incisions (11% vs. 4.7%; P=0.006). In contrast, the incidence of ventral hernia was only 0.7% after laparoscopy. A compilation of all the studies comparing laparotomy to laparoscopy showed a significantly higher incidence of incisional hernia after laparotomy (P=0.001). Independent risk factors for incisional hernia included age and infectious complications. Only two meta-analyses were able to show a significant decrease in risk-related to the use of non absorbable or slowly absorbable suture material. No difference in incisional hernia risk was shown with different suture techniques (11.1% for running suture, 9.8% for interrupted sutures: NS).

CONCLUSION

A review of the literature shows that only the choice of incisional approach (transverse incision or laparotomy vs. midline laparotomy) allows a significant decrease in the incidence of ventral incisional hernia.

Intraperitoneal mesh implantation for fascial dehiscence and open abdomen

BACKGROUND

Postoperative fascial dehiscence and open abdomen are severe postoperative complications and are associated with surgical site infections, fistula, and hernia formation at long-term follow-up. This study was designed to investigate whether intraperitoneal implantation of a composite prosthetic mesh is feasible and safe.

METHODS

A total of 114 patients with postoperative fascial dehiscence and open abdomen who had undergone surgery between 2001 and 2009 were analyzed retrospectively. Contaminated (wound class 3) or dirty wounds (wound class 4) were present in all patients. A polypropylene-based composite mesh was implanted intraperitoneally in 51 patients, and in 63 patients the abdominal wall was closed without mesh implantation. The primary endpoint was incidence of incisional hernia, and the incidence of enterocutaneous fistula was a secondary endpoint.

RESULTS

The incidence of enterocutaneous fistulas after wound closure post-fascial dehiscence (13% vs. 6% without and with mesh, respectively) or post-open abdomen (22% vs. 28% without and with mesh, respectively) was not significantly different. The incidence of incisional hernia was significantly lower with mesh implantation compared with no-mesh implantation in both contaminated (4% vs. 28%; p = 0.025) and dirty abdominal cavities (5% vs. 34%; p = 0.01).

CONCLUSIONS

Intra-abdominal contamination is not a contraindication for intra-abdominal mesh implantation. The incidence of enterocutaneous fistula is not elevated despite the presence of contamination. The rate of incisional hernias is significantly reduced after intraperitoneal mesh implantation for postoperative fascial dehiscence or open abdomen.

Long-term follow-up after incisional hernia repair: are there only benefits for symptomatic patients?

INTRODUCTION

Incisional hernias are among the most frequent complications in visceral surgery and are currently considered to be an indication for surgery in all cases, regardless of the patient's symptoms. However, it still remains unclear to what extent surgery actually results in improvement according to objective (e.g., less pain or dysesthesia) or subjective criteria (e.g., less discomfort or better cosmetic result). The purpose of this prospective study was to identify patients who derive objective and subjective benefit from surgical repair.

MATERIALS AND METHODS

This prospective study included patients who underwent open incisional hernia repair with mesh implantation from December 2006 to April 2009. Data were collected before and 18 months after surgery. Pain intensity was rated on the numerical analog scale (NAS) pre- and postoperatively. Patients were divided into oligosymptomatic (NAS 0-3) and symptomatic (NAS 4-10) groups based on their preoperative pain level, and the postoperative outcome of the two groups was compared by standardized questionnaire.

RESULTS

Ninety patients were prospectively enrolled, 45 (50 %) of each gender. Prior to surgery, 43 patients (47.8 %) were oligosymptomatic, and 47 (52.2 %) reported clinically relevant pain. Eighteen months after surgery, 7.5 % of the oligosymptomatic patients complained of clinically relevant pain; its rate remained unchanged. The symptomatic group showed a significant reduction in clinically relevant pain from 100 % to 14.0 %, (p < 0.001). The percentage of patients with clinically relevant dysesthesia was 12.5 % in the oligosymptomatic and 20.9 % in the symptomatic group 18 months postoperatively. The overall recurrence rate was 13.3 % after 18 months without difference in both groups. A reduction in discomfort in the surgical area was reported by 77.5 % of the oligosymptomatic and 79.1 % of the symptomatic patients.

CONCLUSIONS

Symptomatic patients definitely profit from surgical repair in the long-term course. However, the notable postoperative rate of clinically relevant pain and dysesthesia in oligosymptomatic patients and their high recurrence rate cast doubt on whether they really benefit from surgical repair. The remarkable degree of subjective satisfaction in oligosymptomatic patients should not be underestimated.

[Contribution of the Study Center of the German Surgical Society to evidence based surgery]

Since the Study Center of the German Surgical Society (SDGC) was established in 2003 it has been supporting surgeons to implement their ideas for multicenter randomized studies. Assistance is provided for development (sample size calculation, protocol, funding application) implementation (submission to ethics committee, data management, monitoring) and analysis (statistical analysis, publication) in close collaboration with biometricians and data managers. Currently more than 2,500 patients have been included in 11 trials. The most complex SDGC study (SYNCHRONOUS) so far with up to 80 participating centers has been activated in September 2011. Furthermore, there is an increasing relevance for systematic reviews and meta analyses with regard to the development of studies and aggregation of results. For this reason a systematic review working group was established within the SDGC. To date 13 publications have been completed and 8 more are underway.

[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.

Standard abdominal wound edge protection with surgical dressings vs coverage with a sterile circular polyethylene drape for prevention of surgical site infections (BaFO): study protocol for a randomized controlled trial

Background

Postoperative surgical site infections cause substantial morbidity, prolonged hospitalization, costs and even mortality and remain one of the most frequent surgical complications. Approximately 14% to 30% of all patients undergoing elective open abdominal surgery are affected and methods to reduce surgical site infection rates warrant further investigation and evaluation in randomized controlled trials.

Methods/design

To investigate whether the application of a circular plastic wound protector reduces the rate of surgical site infections in general and visceral surgical patients that undergo midline or transverse laparotomy by 50%. BaFO is a randomized, controlled, patient-blinded and observer-blinded multicenter clinical trial with two parallel surgical groups. The primary outcome measure will be the rate of surgical site infections within 45 days postoperative assessed according to the definition of the Center for Disease Control. Statistical analysis of the primary endpoint will be based on the intention-to-treat population. The global level of significance is set at 5% (2 sided) and sample size (n = 258 per group) is determined to assure a power of 80% with a planned interim analysis for the primary endpoint after the inclusion of 340 patients.

Discussion

The BaFO trial will explore if the rate of surgical site infections can be reduced by a single, simple, inexpensive intervention in patients undergoing open elective abdominal surgery. Its pragmatic design guarantees high external validity and clinical relevance.

Trial registration

http://www.clinicaltrials.gov NCT01181206. Date of registration: 11 August 2010; date of first patient randomized: 8 September 2010

[Surgical research in Germany. Organization, quality and international competitiveness]

Surgical research in Germany is performed within surgical clinics by individual working groups or in surgical research divisions. Additionally, a few independent institutes and departments of surgical research have been established at medical faculties. The number of these institutions, however, is too small. To increase productivity in surgical research, structural changes are necessary, including additional establishment of further institutes and professorships. The quality of clinical research in surgery in Germany is critically discussed. International comparison shows that Germany has a low ranking with respect to the number of clinical studies published in leading surgical journals. However, there has been some improvement in the quality of clinical studies performed in surgical departments during the last 15 years. The establishment of the study center of the German Society of Surgery shows that excellent clinical studies with adequate numbers of patients can also be performed in Germany and can be published in leading journals. Accordingly, there is need to distribute the structures and the competence necessary to perform clinical studies in a standardized manner to all surgical departments involved in clinical research. The experimental surgical research in Germany is not adequately visible, although over the last 10 years the most relevant publications from institutions for surgical research have been placed in journals with a mean impact factor of 8. This may be due to the fact that 85% of these top publications are published in non-surgical journals. The aim for the future must therefore be to increase the impact factor and, thus, the attractiveness of surgical journals. This may be achieved by publishing the highest quality results from experimental surgical research not in non-surgical but in surgical journals.

To whom do the results of the multicenter, randomized, controlled INSECT trial (ISRCTN 24023541) apply?--assessment of external validity

A response to Seiler et al: Interrupted or continuous slowly absorbable sutures for closure of primary elective midline abdominal incisions: a multicenter randomized trial (INSECT: ISRCTN24023541). Ann Surg 2009, 249(4):576-582.

Development of a clinical trial to determine whether watchful waiting is an acceptable alternative to surgical repair for patients with oligosymptomatic incisional hernia: study protocol for a randomized controlled trial

BACKGROUND

Incisional hernia is a frequent complication in abdominal surgery. This article describes the development of a prospective randomized clinical trial designed to determine whether watchful waiting is an acceptable alternative to surgical repair for patients with oligosymptomatic incisional hernia.

METHODS/DESIGN

This clinical multicenter trial has been designed to compare watchful waiting and surgical repair for patients with oligosymptomatic incisional hernia. Participants are randomized to watchful waiting or surgery and followed up for two years. The primary efficacy endpoint is pain/discomfort during normal activities as a result of the hernia or hernia repair two years after enrolment, as measured by the hernia-specific Surgical Pain Scales (SPS). The target sample size of six hundred thirty-six patients was calculated to detect non-inferiority of the experimental intervention (watchful waiting) in the primary endpoint. Sixteen surgical centers will take part in the study and have submitted their declaration of commitment giving the estimated number of participating patients per year. A three-person data safety monitoring board will meet annually to monitor and supervise the trial.

DISCUSSION

To date, we could find no published data on the natural course of incisional hernias. To our knowledge, watchful waiting has never been compared to standard surgical repair as a treatment option for incisional hernias. A trial to compare the outcome of the two approaches in patients with oligosymptomatic incisional hernias is urgently needed to provide data that can facilitate the choice between treatment options. If watchful waiting was equal to surgical repair, the high costs of surgical repair could be saved. The design for such a trial is described here. This multicenter trial will be funded by the German Research Foundation (DFG). The ethics committee of the Charité has approved the study protocol. Approval has been obtained from ten study sites at time of this submission. The electronic Case Report Forms have been created. The first patient was to be randomized November 14th, 2011. An initiation meeting took place in Berlin January 9th, 2012.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01349400.

Clustering in surgical trials--database of intracluster correlations

BACKGROUND

Randomised trials evaluation of surgical interventions are often designed and analysed as if the outcome of individual patients is independent of the surgeon providing the intervention. There is reason to expect outcomes for patients treated by the same surgeon tend to be more similar than those under the care of another surgeon due to previous experience, individual practice, training, and infrastructure. Such a phenomenon is referred to as the clustering effect and potentially impacts on the design and analysis adopted and thereby the required sample size. The aim of this work was to inform trial design by quantifying clustering effects (at both centre and surgeon level) for various outcomes using a database of surgical trials.

METHODS

Intracluster correlation coefficients (ICCs) were calculated for outcomes from a set of 10 multicentre surgical trials for a range of outcomes and different time points for clustering at both the centre and surgeon level.

RESULTS

ICCs were calculated for 198 outcomes across the 10 trials at both centre and surgeon cluster levels. The number of cases varied from 138 to 1370 across the trials. The median (range) average cluster size was 32 (9 to 51) and 6 (3 to 30) for centre and surgeon levels respectively. ICC estimates varied substantially between outcome type though uncertainty around individual ICC estimates was substantial, which was reflected in generally wide confidence intervals.

CONCLUSIONS

This database of surgical trials provides trialists with valuable information on how to design surgical trials. Our data suggests clustering of outcome is more of an issue than has been previously acknowledged. We anticipate that over time the addition of ICCs from further surgical trial datasets to our database will further inform the design of surgical trials.

Tension of knotted surgical sutures shows tissue specific rapid loss in a rodent model

BACKGROUND

Every surgical suture compresses the enclosed tissue with a tension that depends from the knotting force and the resistance of the tissue. The aim of this study was to identify the dynamic change of applied suture tension with regard to the tissue specific cutting reaction.

METHODS

In rabbits we placed single polypropylene sutures (3/0) in skin, muscle, liver, stomach and small intestine. Six measurements for each single organ were determined by tension sensors for 60 minutes. We collected tissue specimens to analyse the connective tissue stability by measuring the collagen/protein content.

RESULTS

We identified three phases in the process of suture loosening. The initial rapid loss of the first phase lasts only one minute. It can be regarded as cutting through damage of the tissue. The percentage of lost tension is closely related to the collagen content of the tissue (r = -0.424; p = 0.016). The second phase is characterized by a slower decrease of suture tension, reflecting a tissue specific plastic deformation. Phase 3 is characterized by a plateau representing the remaining structural stability of the tissue. The ratio of remaining tension to initial tension of phase 1 is closely related to the collagen content of the tissue (r = 0.392; p = 0.026).

CONCLUSIONS

Knotted non-elastic monofilament sutures rapidly loose tension. The initial phase of high tension may be narrowed by reduction of the surgeons' initial force of the sutures' elasticity to those of the tissue. Further studies have to confirm, whether reduced tissue compression and less local damage permits improved wound healing.

Evaluation of the safety and efficacy of MonoMax® suture material for abdominal wall closure after primary midline laparotomy-a controlled prospective multicentre trial: ISSAAC [NCT005725079]

Purpose

Different suture techniques and various suture materials are in use to close midline incisions after primary laparotomy. The ISSAAC study aimed to assess the safety and efficacy of the new ultra-long-term absorbable, elastic monofilament suture material MonoMax® for abdominal wall closure.

Methods

This is a single-arm, multicentre prospective study that included 150 patients undergoing a primary elective midline incision. The control group consists of 141 patients from the INSECT study who received MonoPlus® or PDS® for abdominal wall closure. The incidences of burst abdomen and wound infection until the day of discharge were defined as the primary composite endpoints. The rate of incisional hernias 1 year after surgery, the length of postoperative hospital stay and safety parameters served as secondary endpoints. The study has been registered under www.clinicaltrials.gov [NCT005725079].

Results

Eleven patients in the ISSAAC study [7.3%; 95% CI = (3.9; 13.1%)] experienced wound infection or burst abdomen until the day of discharge as compared to 16 [11.3%; 95% CI = (6.6; 17.8%)] patients in the INSECT control group (p = 0.31). The length of postoperative hospital stay was comparable in both study groups. One year after surgery, incisional hernias were observed in 21 ISSAAC patients (14.0%) in contrast to 30 hernias (21.3%) in the INSECT control group.

Conclusions

The ultra-long-term absorbable, elastic monofilament suture material MonoMax® is safe and efficient for abdominal wall closure.

Prevention of abdominal wound infection (PROUD trial, DRKS00000390): study protocol for a randomized controlled trial

Background

Wound infection affects a considerable portion of patients after abdominal operations, increasing health care costs and postoperative morbidity and affecting quality of life. Antibacterial coating has been suggested as an effective measure to decrease postoperative wound infections after laparotomies. The INLINE metaanalysis has recently shown the superiority of a slowly absorbable continuous suture for abdominal closure; with PDS plus^® such a suture has now been made available with triclosan antibacterial coating.

Methods/Design

The PROUD trial is designed as a randomised, controlled, observer, surgeon and patient blinded multicenter superiority trial with two parallel groups and a primary endpoint of wound infection during 30 days after surgery. The intervention group will receive triclosan coated polydioxanone sutures, whereas the control group will receive the standard polydioxanone sutures; abdominal closure will otherwise be standardized in both groups. Statistical analysis is based on intention-to-treat population via binary logistic regression analysis, the total sample size of n = 750 is sufficient to ensure alpha = 5% and power = 80%, an interim analysis will be carried out after data of 375 patients are available.

Discussion

The PROUD trial will yield robust data to determine the effectiveness of antibacterial coating in one of the standard sutures for abdominal closure and potentially lead to amendment of current guidelines. The exploration of clinically objective parameters as well as quality of life holds immediate relevance for clinical management and the pragmatic trial design ensures high external validity.

Trial Registration

The trial protocol has been registered with the German Clinical Trials Register (DRKS00000390).

Incisional hernia after abdominal closure with slowly absorbable versus fast absorbable, antibacterial-coated sutures

BACKGROUND

Incisional hernia remains among the most common complications after midline incision of the abdominal wall. The role of the suture material used for abdominal wall closure remains controversial. To decrease bacterial adherence to surgical sutures, braided suture materials with antibacterial activity (Vicryl plus, Ethicon, Inc) were developed. This is the first study to analyze long-term results using an antibacterial-braided suture material for abdominal wall closure in a large clinical trial.

METHODS

To analyze the effects of Triclosan-coated suture material (Vicryl plus) on the development of incisional hernia, we performed a 36-month follow-up of 1,018 patients who had a primary midline incision for elective abdominal surgery. In the first time period, a PDS II loop suture was used. In the second observation period, we used Vicryl plus. All variables were recorded prospectively in a database. The primary outcome was the number of incisional hernias. Risk factors for the development of incisional hernias were collected prospectively to compare the 2 groups.

RESULTS

The overall incisional hernia rate in the 36-month follow-up period was 14.6%. Analyzing the influence of the suture material used on the development of incisional hernia, we did not find differences between the 2 groups (PDS II, 14%; Vicryl plus, 15.2%). In the multivariate analysis of possible factors in the study population, only body mass index (BMI) showed a significant influence on the development of incisional hernias. Despite the incidence of wound infections being less in the Vicryl plus group (6.1% vs 11.9%; P < .05), there were no difference in incidence of incisional hernia between the 2 groups.

CONCLUSION

Fast absorbable sutures with antibacterial coating (Tricosan) do not increase the hernia rate after midline abdominal incision compared with slowly absorbable sutures, when wound infection rates are decreased by coating the fast absorbable suture with Triclosan. The development of incisional hernia is significantly increasing in patients with a BMI >30 kg/m(2).

A multicenter randomized controlled trial evaluating the effect of small stitches on the incidence of incisional hernia in midline incisions

BACKGROUND

The median laparotomy is frequently used by abdominal surgeons to gain rapid and wide access to the abdominal cavity with minimal damage to nerves, vascular structures and muscles of the abdominal wall. However, incisional hernia remains the most common complication after median laparotomy, with reported incidences varying between 2-20%. Recent clinical and experimental data showed a continuous suture technique with many small tissue bites in the aponeurosis only, is possibly more effective in the prevention of incisional hernia when compared to the common used large bite technique or mass closure.

METHODS/DESIGN

The STITCH trial is a double-blinded multicenter randomized controlled trial designed to compare a standardized large bite technique with a standardized small bites technique. The main objective is to compare both suture techniques for incidence of incisional hernia after one year. Secondary outcomes will include postoperative complications, direct costs, indirect costs and quality of life. A total of 576 patients will be randomized between a standardized small bites or large bites technique. At least 10 departments of general surgery and two departments of oncological gynaecology will participate in this trial. Both techniques have a standardized amount of stitches per cm wound length and suture length wound length ratio's are calculated in each patient. Follow up will be at 1 month for wound infection and 1 year for incisional hernia. Ultrasound examinations will be performed at both time points to measure the distance between the rectus muscles (at 3 points) and to objectify presence or absence of incisional hernia. Patients, investigators and radiologists will be blinded during follow up, although the surgeon can not be blinded during the surgical procedure.

CONCLUSION

The STITCH trial will provide level 1b evidence to support the preference for either a continuous suture technique with many small tissue bites in the aponeurosis only or for the commonly used large bites technique.

[Evidence-based antibiotic prophylaxis in general and visceral surgery]

The use of prophylactic perioperative antibiotic therapy if indicated could successfully and safely prevent surgical wound infections. The current guidelines (S1) for prophylactic perioperative antibiotic therapy of the Study Group of the Scientific Medical Associations (AWMF) of 2004 was replaced by a recommendation of the study group of the Paul-Ehrlich-Gesellschaft for Chemotherapy (PEG) in 2010. This recommendation includes recent research data from 2000 to 2008. Indications and choice of antibiotic agent depend on specific risk factors of the patient and the operation performed. The aim of this article is to describe the current recommendations of the PEG for general and visceral surgery.

Loss of mechanical strain impairs abdominal wall fibroblast proliferation, orientation, and collagen contraction function

BACKGROUND

Laparotomy wound load forces are reduced when dehiscence and incisional hernia formation occur. The purpose of this study was to determine the effects of strain loss on abdominal fascial fibroblast proliferation, orientation, and collagen compaction function.

METHODS

Cultured rat linea alba fibroblasts were subjected to continuous cyclic strain (CS), CS interrupted at 24 or 48 hours followed by culture at rest (IS-24 and IS-48) or were cultured without mechanical strain (NS). Cell number was measured and images analyzed for cell orientation. Fibroblasts from these groups were seeded onto the surface of (FPCL-S) or mixed into (FPCL-M) a collagen gel matrix and gel area was measured over time.

RESULTS

Continuous strain stimulated proliferation when compared with the nonstrained cells. The loss of strain (IS) delayed proliferation compared with CS throughout (P < .05). CS fibroblasts aligned perpendicular to the direction of strain within 12 hours. Within 12 hours of strain loss, IS-48 fibroblasts became significantly less aligned (P < .0001), and seemed similar to the randomly organized NS fibroblasts 48 hours after strain removal. The CS and IS-24 groups demonstrated faster and greater overall FPCL-M compaction than both the IS-48 and NS groups (P < .0002). The CS group contracted the gel faster than the NS group in FPCL-S (P = .029).

CONCLUSION

Mechanical strain rapidly induces a proliferative, morphologic, and functional response in abdominal wall fibroblasts that is dependent on the continued presence of the strain signal and quickly lost when the load force is removed. The loss of wound edge tension that occurs during laparotomy wound separation and hernia formation may contribute to impaired wound healing through loss of a key stimulatory mechanical signal with important implications for abdominal wall reconstruction.

Measures to prevent surgical site infections: what surgeons (should) do

BACKGROUND

The present study was designed to evaluate surgeons' strategies and adherence to preventive measures against surgical site infections (SSIs).

MATERIALS AND METHODS

All surgeons participating in a prospective Swiss multicentric surveillance program for SSIs received a questionnaire developed from the 2008 National (United Kingdom) Institute for Health and Clinical Excellence (NICE) clinical guidelines on prevention and treatment of SSIs. We focused on perioperative management and surgical technique in hernia surgery, cholecystectomy, appendectomy, and colon surgery (COL).

RESULTS

Forty-five of 50 surgeons contacted (90%) responded. Smoking cessation and nutritional screening are regularly propagated by 1/3 and 1/2 of surgeons, respectively. Thirty-eight percent practice bowel preparation before COL. Preoperative hair removal is routinely (90%) performed in the operating room with electric clippers. About 50% administer antibiotic prophylaxis within 30 min before incision. Intra-abdominal drains are common after COL (43%). Two thirds of respondents apply nonocclusive wound dressings that are manipulated after hand disinfection (87%). Dressings are usually changed on postoperative day (POD) 2 (75%), and wounds remain undressed on POD 2-3 or 4-5 (36% each).

CONCLUSIONS

Surgeons' strategies to prevent SSIs still differ widely. The adherence to the current NICE guidelines is low for many procedures regardless of the available level of evidence. Further research should provide convincing data in order to justify standardization of perioperative management.

Randomised prospective study of abdominal wall closure in patients with gynaecological cancer

BACKGROUND

Median laparotomy is the most common approach to the abdominopelvic cavity in patients with gynaecological tumours.

AIMS

The primary endpoint of the study was to evaluate the onset of incisional hernia. The secondary endpoint was to evaluate the onset of infection, wound dehiscence, wound infection, and scar pain during the post-operative period.

METHODS

A total of 191 patients were eligible for the study. They were divided into three groups. Group A underwent en bloc closure of the peritoneum and fascia with Premilene suture, Group B en bloc closure of the peritoneum and fascia with Polydioxanone suture, and Group C separate closure of the peritoneum and fascia with single stitches of Ethibond suture. Statistical analysis was performed using the Statistical Software Package for Social Sciences 12.0.

RESULTS

Group A and Group B comprised 63 patients, and Group C included 65 patients. The three groups proved homogeneous on statistical analysis (P > 0.05). The statistical analysis did not reveal significant differences between the different suture types and techniques with respect to the incidence of incisional hernia (P > 0.05).

CONCLUSION

In our study, the incidence of incisional hernia was 8%. Randomised patients were homogeneous for sample size and risk factors. No significant differences were found between suture types or techniques. Currently, there is no suture material or technique that can be considered superior to others. When possible, we believe that the best way to prevent incisional hernia is to preserve the integrity of the abdominal wall using minimally invasive techniques.