Interrupted Or Continuous Slowly Absorbable Sutures For Closure Of Primary Elective Midline Abdominal Incisions

Dissections

INTERVENTIONAL 1 May 2009

Evidence-based Medicine for Surgeons

Interrupted or continuous slowly absorbable sutures for closure of primary elective midline abdominal incisions Authors: Seiler CM, Bruckner T, Diener MK, et al Journal: Annals of Surgery 2009; 249:576–582 Centre: Study Center of the German Surgical Society, University of Heidelberg, Heidelberg, Germany

BACKGROUND

Incisional hernia remains the most common long-term complication after midline incisions of the abdominal wall. Risk factors can be divided into patient- and surgeon-related. While the former cannot be standardized or controlled in most cases, the surgical closure technique and material can be optimized to lower the incidence of incisional hernias.

RESEARCH QUESTION Population Patients undergoing elective, primary, midline laparotomy with an expected incision length of 15 cm or more.

Authors' claim(s): “...The incidence of incisional hernias was higher than expected in all groups. In addition, a high frequency of wound infections was observed. New concepts need to be developed and studied to substantially reduce the frequency of incisional hernias.”

IN

SUMMARY Outcome comparison between the three types of fascial closure

Indicator variable Three types of standardized fascial closure Outcome variable Primary: Occurrence of incisional hernia within one year of surgery. Secondary: Burst abdomen, wound infection, pulmonary complication. Comparison Outcome differences between the three types of fascial closure.

Number randomized Died during 1 yr Lost to follow up



ITT (intention to treat) Incisional hernia at 1 yr Wound infection rate





Interrupted Vicryl®

Continuous PDSII ®

Continuous Monoplus ®

210

205

210

14

10

13

44

31

39

176

174

171

28 (15.9%)

15 (8.4%)

22 (12.5%)

26 (12.7%)

39 (19.4%)

33 (16.3%)

None of the differences between the groups were statistically significant There were no differences in the rate of burst abdomen and pulmonary morbidity between the three groups.

THE TISSUE REPORT The authors point out the high incidence of incisional hernia and the huge wound infection rate despite almost all patients having received prophylactic antibiotics and all procedures being elective. The drop out rate in the study is an unacceptable 18%. The authors do not discuss this flaw in their paper. The Vicryl group was closed by an interrupted technique while the other two used running closure. Evidence exists that points to the inferiority of interrupted closure over running. The authors provide no reasonable explanation for this choice of technique. Yet, the Vicryl group had the lowest incisional hernia rate (numerically, though not statistically significant). Overall, the study raises more questions than it provides answers for. It tells us nothing more than what we have known for two decades or more: abdominal fascia is best closed by a running, delayed absorbable, monofilament, mass closure technique.

EBM-O-METER Evidence level

Overall rating

Bias levels

Double blind RCT

Sampling

Randomized controlled trial (RCT) Prospective cohort study - not randomized Case controlled study Case series - retrospective

Trash Life's too short for this

Swiss cheese Full of holes

Safe Holds water



Newsworthy “Just do it”

Comparison Measurement

l | Novel l | Feasible l Ethical l | Resource saving l

Interesting

The devil is in the details (more on the paper) ...

© Dr Arjun Rajagopalan



SAMPLING Sample type Simple random Stratified random Cluster Consecutive Convenience Judgmental

Inclusion criteria

Exclusion criteria

Elective, primary, midline laparotomy with an expected incision length of 15 cm or more  Age > 18 yrs  Survival potential > 1 yr 

Emergency  Under immunosuppressive Rx  Chemotherapy within 2 weeks  Radiation > 8 wk  Coagulopathy  Dementia 

Final score card Vicryl

PDS II

Monoplus

Target

?

?

?

Accessible

?

?

?

Intended

210

205

210

Drop outs

44

31

39

176

174

171

Study

 = Reasonable | ? = Arguable |  = Questionable A priori sample size calculation: (significance = 0.05, power = 80%) 172 patients per group Duration of the study: July 11, 2004 - September 26, 2006 Sampling bias: The drop out rate of 18% is unacceptably high. The authors offer no explanation.

COMPARISON Randomized

Case-control

Non-random

Historical

None

Controls - details Allocation details

The patients were randomized intraoperatively to the 3 fascial closure groups: absorbable braided material (Vicryl) applied as an interrupted suture, slowly absorbable monofilament materials, one with longitudinal elasticity (MonoPlus) and one without (PDS II), both as continuous sutures with a wound length: suture length ratio of 4:1. The technique of closure was standardized.

Comparability

The three groups were similar in demographic characteristics and co-morbidties.

Disparity

None reported. No individual analysis of the characteristics of the drop outs is offered.

Comparison bias: The decision to use Vicryl as an interrupted suture and the other two as continuous is questionable. Evidence exists in support of continuous closures being more secure than interrupted. This renders the comparisons as biased. The authors provide no explanation for this choice.

MEASUREMENT Measurement error

1.Ultrasound evaluation of incisional hernia

Y

N

?

-

-

Blinding

Scoring

N

Protocols

?

Training

Y

Observer error Gold std.

Device error Device suited to task

Repetition

Device used

-

Y

Measurement bias: The authors give no description of the method by which ultrasound was used to detect incisional hernia other than the statement: "Incisional hernia was defined as a fascial dehiscence after completed superficial wound healing with or without a prolapse of abdominal organs, confirmed by abdominal ultrasound."

© Dr Arjun Rajagopalan