Abstract: 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). 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.

Plain-language summary: We identified five RCTs with a total of 827 participants. Seven hundred thirty participants (384 received continuous sutures and 346 interrupted sutures) provided data for this review. Participants had abdominal or groin operations. The only outcomes reported were, superficial surgical site infection, superficial wound breakdown and length of hospital stay. No other important outcomes, including quality of life, long-term patient outcomes and use of healthcare resources, were reported. Approximately 6% of participants developed superficial surgical site infection, but there was no significant difference between the two groups in the proportion of participants who developed these. Approximately 4% of participants developed superficial wound breakdown. The proportion of participants with this problem in the continuous suture group was approximately one-tenth of that in the interrupted suture group. Most wound breakdowns occurred in two trials that used absorbable sutures for continuous suturing and non-absorbable sutures for interrupted suturing. Non-absorbable sutures are removed seven to nine days after surgery, but absorbable sutures are not removed, and so support the wound for longer - which may account for the difference in distribution of this problem between groups. There was no significant difference between groups for length of hospital stay. Superficial wound breakdown is reduced by continuous subcuticular suturing. However, the trials that contributed to this result had suture removal in only one group (interrupted sutures), which may have led to this observation. The number of participants included in this review was small and follow-up after surgery was short. The overall quality of evidence was very low. Levels of bias across the studies were mostly high or unclear, so there may have been flaws in trial organisation that could produce erroneous results. Further well-designed trials at low risk of bias are necessary.