We performed an updated meta‐analysis to compare the efficacy of the zipper device and sutures for wound closure after surgery. A computerised literature search was performed for published trials in PubMed, Web of Science, the Cochrane Library, and Google Scholar. Two reviewers independently scrutinised the trials, extracted data, and assessed the quality of trials. The primary outcome was surgical site infections (SSI). The secondary outcomes were wound dehiscence, total wound complications, wound closure time, and scar score. Statistical analysis was performed in the Stata 12.0. Of the 130 citations, eight trials (1207 participants) met eligibility criteria and were included. The zipper device achieved a lower SSI rate (RR: 0.63, [95% CI: 0.41‐0.96, P = 0.032]), a shorter wound closure time (SMD: −8.53 [95% CI: −11.93 to −5.13, P = 0.000]) and a better scar score (SMD: 0.42 [95% CI: 0.22‐0.62, P = 0.000]) than sutures. No significant difference was shown in the incidence of wound dehiscence and total wound complications. Therefore, the zipper device provides the advantages of anti‐infection, time‐saving, and cosmesis for wound closure.
Recently, a novel atraumatic, noninvasive zipper surgical wound closure device has become popular in orthopaedic and cardiothoracic surgical procedures. 6 , 8 , 9 , 10 It is sterile, adjustable, hydrocolloid adhesive‐based, and designed to replace staples and sutures for closure of the superficial skin layer, which can be applied directly to intact skin on either side of the incision and provides uniform force along the wound edge. 8 The similar incidence of SSI between the zipper and sutures was reported. 5 , 11 Two previous meta‐analyses of randomised controlled trials (RCTs) on this topic have been published in 2016 and 2020, respectively. 5 , 11 However, both were limited by small sample sizes with very low‐certainty evidence. Consequently, we perform an updated meta‐analysis by combining five RCTs 12 , 13 , 14 , 15 , 16 from prior meta‐analyses and three additional studies 17 , 18 , 19 (two RCTs) in order to clarify the state of the evidence. Furthermore, we also attempted to illuminate the limitations of current studies and to provide suggestions for further studies.
The goals of wound closure are to enable rapid skin healing and prevent infection, and to facilitate early mobilisation while achieving a good cosmetic result. A variety of materials including sutures, skin staples, tissue adhesives, and surgical tapes have been used in surgical wound closure. 5 Sutures and staples are most commonly used, but staples can cause infections, bleed, additional dress, or scar formation on piercing sites after removed. 6 Furthermore, current evidence indicates the risk of postoperative infection is not lower with sutures than staples for skin closure. 7
It is estimated that 312.9 million operations are performed every year worldwide. 1 Skin closure is an integral step of operation that influences cosmesis and satisfaction, and is associated with the absence or presence of wound complications. Surgical wound complications such as surgical site infections (SSI) increase use of antibiotics and revision surgery, lead to prolonged hospital stays and readmission, and increased healthcare costs. 2 , 3 , 4 Meanwhile, unsightly scars will cause significant undesired physiological and psychological effects if wound do not heal correctly.
Statistical analysis was performed in the Stata (version 12.0). Heterogeneity between studies was quantified by calculating the I 2 statistic. P > 0.1 or I 2 < 50% was considered to be no significantly inconsistent and was derived using a fixed‐effects model. Otherwise, a random‐effects model was used. Risk ratio (RR) was calculated for included studies that reported raw counts with 95% confidence interval (CI). The standardised mean difference (SMD) and its 95% CI represent consecutive outcomes results. All P values were two‐sided, and P < 0.05 was considered statistically significant. Finally, removing a trial one by one is used as sensitivity analysis for the robustness assessment of results of meta‐analyses.
We evaluated the risks of bias of the included trials according to the Cochrane Handbook for Systematic Reviews of Interventions. 21 Study quality of RCTs was assessed in the Review Manager (RevMan version 5.1), including random generation, allocation concealment, blindness of patients and personnel, blindness of outcome estimators, incomplete outcome data, selective reporting, and other bias. The nine‐star Newcastle‐Ottawa Scale (NOS) was used to evaluate the quality of non‐randomized studies. 22 The scores of the items identifying study quality varied from zero to nine according to the following categories: selection of cohorts (four items), comparability of cohorts (one item), and assessments of outcomes (three items). Any disagreement was settled by a group discussion with a third investigator.
Wound dehiscence was reported in five studies (one excluded) involving 699 patients. Figure showed no significant statistical heterogeneity between the studies (I 2 = 34.9%, P = 0.203) and the pooled RR was 0.66 (95% CI = 0.27‐1.59, P = 0.354). Compared with suture, zipper did not decrease the incidence of wound dehiscence. Five studies involving 699 patients reported total wound complications. The pooled result derived from the random‐effects model is presented in Figure . The pooled RR was 0.62 (95% CI = 0.15‐2.53, P = 0.502) indicated no significant difference in the incidence of total wound complications between two groups. Five trials involving 639 patients reported data for the wound closure time. Figure shows the pooled result derived from the random‐effects model, the pooled SMD was −8.53 (95% CI = −11.93 to −5.13, P = 0.000). Thus, the application of zipper significantly shortened the time of wound closure compared with that of closure. Four studies provided detailed data of scar score for cosmesis. Given that different rating scales were adopted among the studies, the pooled results were showed in two forest plots (Figure : low score representing satisfaction; Figure : low score representing dissatisfaction). Figures and show the pooled SMD was −0.72 (95% CI = −1.55 to 0.11, P = 0.09) and 0.42 (95% CI = 0.22‐0.62, P = 0.000) and it is easily found the zipper has tendency to a better cosmetic result in forest plots.
The bias of the eligible seven RCTs is summarised in Figure . Only three trials reported how they generated random sequences, four trials reported how they concealed allocation, no trial blinded patients and personnel, and two trials blinded evaluators. As illustrated in Figure , the risk of biases of these selected studies was a bit high. The quality of only one nonRCT (retrospective cohort study) was evaluated according to the NOS. The selection scores, comparability scores, and assessment scores was three, two, and three, respectively. A total score of eight indicate that the quality of the article is good.
These studies (seven RCTs and one nonRCT) involved a total of 1207 participants (597 in the zipper group and 610 in the suture group) were published between 2002 and 2019. The baseline characteristics of patients in each trial were similar (Table ). Wounds from at least five different sites were recorded, and detail of wound closure was listed in Table .
SSI is a serious complication occurring after surgical operations. In USA, SSI is the most common (31%) healthcare‐associated infection. 23 Although several meta‐analyses had attempted to clarify the differential SSI risk between skin closure modalities, an ideal modality with both anti‐infection and cosmesis effects remains uncertainly as wound cosmesis is currently considered more important than it was previously. 5 , 7 , 11 , 24 Tissue adhesives may provide a better cosmetic result but they are used less widespread due to the problems with wound dehiscence. A novel zipper skin closure device has been developed to overcome these problems, but no significantly difference of SSI between the zipper and subcuticular sutures was found in the previous meta‐analyses. 5 , 11 In order to expand sample size, a related study published in 2019 17 was added, and two additional studies (one adopted conventional nylon suture, 19 one not mentioned subcuticular 18 ) were also included in view of the similar incidence of SSI (RR = 1.10, 95% CI = 0.80‐1.52) between subcuticular sutures and transdermal sutures. 5 Then, an updated meta‐analysis was performed to clarify the state of the evidence.
The most encouraging finding of current meta‐analysis was that zipper could decrease the incidence of SSI compared with sutures, which is quite different from the results reported in previous meta‐analyses. The sample size in previous studies was too small and the level of evidence was low may be the main cause of this discrepancy. A possible explanation for the great therapeutic effect might be the atraumatic and non‐invasive advantage of zipper in wound closure. The zipper involves no needles and sharps while sutures puncturing the skin and promoting the access of bacteria into the underlying tissue. In addition, bacterial adhere to surgical sutures and protected from phagocytosis are important factors in the development of postoperative wound infection. 13 Furthermore, the zipper will not be opened until removal in most cases and the wound being covered until it healed, thus avoid the risk of bacterial contamination at the time of dressing change as the sutures used.
Similar to the results reported in previous meta‐analyses, a shorter wound closure time in the operation and a better scar score (cosmetic result) were also observed. In part, short wound closure time could decrease the risk of surgical‐associated complications and costs. 14 , 16 No doubt that suture closure is time‐consuming and requires great skill, but the zipper closure can be applied easily without advanced surgical skills that decrease the technical variation in suturing by different surgeons and promotes standardisation of wound closure. 10 The patient demand of acquiring good cosmetic appearance of wound closure is commonly. In a study by Levi et al 25 indicated zipper device provides greater shielding of the wound from perturbation caused by distraction forces than sutures. The zipper device provides precise, adjustable, and tension‐free adaptation of the incision edges for a sufficient time and minimal trauma to the skin and underlying tissues, without resulting in an ischemic condition that could impact healing and scarring, thus make it beneficial to a good cosmetic result. 16 , 26 Several studies reported similar results that a better cosmesis was observed in the zipper group compared with stapler group. 6 , 8 , 26 Furthermore, a distinctive feature of the zipper was that no need of removing sutures and bandages thus cause less painful, which further improved the patient satisfactions.
The incidence of wound dehiscence and total wound complications were no significant discrepancy between the zipper and sutures in current meta‐analysis. Theoretically, the atraumatic, non‐invasive, and stable mechanical properties of zipper device provides unique benefits for avoiding wound complications. However, complications specific to a new device must be highlighted, including skin peeling, skin discoloration, epidermolysis, blisters, allergic reaction to the adhesive tape area, pruritus in patient with dry skin, and exfoliation of the device. 8 , 9 , 15 , 27 Thus, the zipper device need to be further improved in order to overcome these problems.
The choice between the zipper and sutures should be based on factors such as local availability, cost, surgeon preference, and individual constitution and wishes of patients. For example, the zipper device is particularly beneficial for the black race because keloid formation is a common problem among them, and it can also be used on patients with cicatricial skin or who want less scars. 19 Given the advantages of less pain, making it especially popular in paediatric patients. 15 The zipper shorten the wound closure time make it provide a unique benefit for patient who cannot tolerate a long period of surgery. For the same reason, in the emergency department, it can not only be used effectively in would closure, but also shorten the waiting time for other patients. 28 In addition, the use of this device is not affected by different surgeons or the length of the wound. 15 Therefore, it may be a good choice for surgeon who with poor stitching skill and for patient who with long wound. Furthermore, patients have the ability to remove the closure device themselves that highlight the potential clinical and economic utility. 9 , 29 Last but not least, the zipper device also reduces the personal risk of injury while stitching or dressing the wound, thus protects surgeon from infectious diseases such as HIV and hepatitis. 19 In a word, the zipper device provides an inestimable benefit for health care system.
However, the results of this meta‐analysis should be interpreted in light of its limitations. First, the sample size remains insufficient that will decrease the level of evidence. Second, studies exist different degrees of bias risk, most of trials lacking blinding and allocation concealment. Third, potential biases are likely to be greater for a nonRCT was included. Fourth, language limitation to English may weaken the applicability of the conclusions. In addition, different suture types (subcuticular or non‐subcuticular) and materials (absorbable or non‐absorbable) were included together may limit the generalizability of the results. The choice to combine different suture types and materials into one treatment group was because there remains insufficient evidence to suggest that any differences between suture types or materials contribute to differential risk in SSI. The discrepancy between the zipper devices also should be considered, theoretically, a transparent zipper device (Lalani et al, 18 Tanaka et al 15 and Koerber et al 17 ) can be more conducive to wound inspection and avoid the development of complications in time than opaque device (Roolker et al, 14 Risnes et al 12 , 13 and Xu et al 16 ). Also, the discrepancy of incision location and patient baseline data between different studies may affect the convincingness of the results. The true rate of SSI or other complications might be underestimated give that some studies reporting only short‐term follow‐up. Furthermore, cosmetic results were evaluated with different scales. Therefore, the practical outcome should be well documented in more large RCTs. Future studies should be informed by the results of current meta‐analysis to be well designed that ensure low risk of bias across the domains of patient selection, suture materials selection, surveillance for outcomes, and completeness of patient follow‐up. A comparison of the zipper and absorbable suture closure will be a future investigation. When the number of RCTs is sufficient, a new meta‐analysis should be performed to further verify current results, and it is necessary to conduct subgroup analyses according to suture materials, wound location, and surgery type, etc.