Most surgery descriptions in books suggest that subcutaneous soft tissue is repaired using absorbable sutures at the end of surgery and after closing the fascia; then, the skin is repaired by non-absorbable sutures [1]. Subcutaneous absorbable sutures are known to have several advantages like omitting the subcutaneous for avoiding seroma collection [2], reducing tension in wound edges for bringing the sides together and having a softer scar after suturing. However, some outcomes of subcutaneous sutures may be a longer operation time, reaction to absorption stages of subcutaneous absorbable sutures [3-5] (Table 1) and an increase in final costs of surgeries. Since few studies have been conducted on the possibility of avoiding subcutaneous sutures around the world and no similar studies have been carried out in Iran, we decided to conduct a comparative study on using and avoiding subcutaneous sutures before final repair.

Table 1: Distribution of patients in studied groups.

This single blind randomized clinical trial was conducted on all eligible orthopedic surgery candidates who referred to Sina Hospital during six years from 2003 to 2009. Since no similar study has been conducted on orthopedic patients and as maximizing power and minimizing type I and II was necessary, all eligible patients who had undergone surgery during the mentioned time were enrolled for the study. The proposal and the methodology of the study were approved by the Research and Medical Ethics Committee of the hospital. This was a single blind study; i.e. the patients were not aware of their classification but the surgeons were informed of their grouping and the required information of the patients in both groups (upper/lower extremity, repairing or not repairing fascia).

Inclusion criteria

All orthopedic surgery candidates with the possibility of primary wound repair who signed the informed consent form and returned for follow ups every three months postoperatively, entered the study. The surgical operations include all elective surgeries with clean wounds, traumas and fractures without the need for leaving the wound open or performing secondary wound repair as well as cases in which cutaneous graft, cutaneous and myocutaneous flap was not required.

Exclusion criteria

Patients with at least one of the following conditions were excluded from the study:

1. Patients whose wound had to be left open or required secondary repair
2. Patients requiring cutaneous graft, cutaneous and myocutaneous flap
3. Incisions<2cm
4. Patient who did not participate in 3-month follow up sessions due to travel, death or uncooperativeness

Method

After executing the inclusion and exclusion criteria, the cases signed an informed consent and were divided into the two major groups of upper and lower extremities. Then, they were assigned to subgroups with and without fascia repair and were randomly classified into with/without subcutaneous repair classes. Simple randomization was carried out using computerized random numbers chart (Table 2). It is to be noted that the basis of the classification was the difference in the repair power of upper and lower extremities and the point that upper and lower limb fascia repair surgeries are conducted above the elbow and knee, respectively. The difference in sample sizes is the result of simple randomization.

Table 2: Comparing complications in studied groups.

In the subcutaneous suture group, absorbable Vicryl was used for repair and each 3 cm of the tissue was sutured; however, non-absorbable nylon braid was used for skin repair. Subcutaneous drain was not used in any of the groups but sub-fascia drain was inserted for all fascia repair cases. The initial wound dressing was changed on the second day, postoperatively. Next dressings were changed every day and on 10^th-14^th day, the sutures were pulled. The patients were examined for skin edge necrosis, cutaneous and dermal reaction (inflammation), infection, dehiscence, fluid and seroma collection in 1^st and 2^nd weeks and 1^st and 3^rd months. The follow up period was three months because Vicryl is completely absorbed within 3 months and soft tissue repair complications usually represent before that. Therefore, the wound status and tensity reaches a plateau during the said time [6].

Dehiscence is defined as an opening of wound edges due to weak sutures without any sign of infection and inflammation. Infection can be determined by pus secreted from the wound and necrosis refers to the discoloration of wound edges into dark blue or black so that the skin is not alive and requires repair. Subcutaneous fluid collection was considered as a case with a clear representation requiring sutures opening and fluid discharge. Cutaneous reaction was only defined as wound edge redness without secretions. It is noteworthy that in some cases where the wound was slightly red and inflamed but was represented in form of infection and pus in subsequent examinations, the latter was considered as the final complication.

Statistical analysis

All the data were entered in SPSS ver. 15 and descriptive statistics were provided for qualitative and quantitative variables (Table 3). The frequency of complications resulting from not having subcutaneous sutures was separately determined; its association with the repair method was obtained in form of sub-group analysis using Chi-square test. The significance of the tests was considered 0.05.

Table 3: Statastical Analysis of Qualitative and Quantitative variables.

After administering the inclusion and exclusion criteria, 14953 patients (1662 females and 1329 males; mean age: 40.6±4.9 yrs.) were enrolled for the study; then, 4153 patients were assigned to the upper extremity and the other 10800 cases were categorized as the lower extremity group. The age range of the former and the latter groups was 4-86 (mean age: 32.3±8.6 yrs.) and 1-103 (mean age: 45.7±8.5 yrs.), respectively. The distribution of the patients and their classification according to having/not having fascia repair and then subcutaneous sutures is presented in Figure 1. The complications were mostly observed in the lower extremity group (355 vs. 47), among the cases without fascia repair (284 vs 118) and in the no-suture group (247 vs 145). The significant difference between the complications in upper and lower extremities was observed in both early (like inflammation) and delayed complications (like infection).

Figure 1: Vicryl braids on the skin surface.

Of the total 176 wound infections, 160 cases were observed during the 2^nd and 3^rd examinations and the rest were detected in the first examination. All complications due to subcutaneous fluid collection or wound edges inflammation were observed during the first examination and the ones resulting from dehiscence and skin edge necrosis were seen in the first and the second examinations.

There was a significant relationship between subcutaneous suturing and complications like skin edge necrosis, coetaneous and dermal reaction (inflammation), infection, dehiscence and subcutaneous seroma and fluid collection, though they were not generally or individually observed in follow up sessions (Figure 2).

Figure 2: Classifying patients into different groups based on upper/lower limb, fascia repair and subcutaneous suture.

Subcutaneous suturing is often recommended at the end of operation and before skin closure [1]. In this study, it is tried to compare the incidence of complications resulting from using or not using subcutaneous sutures in orthopedic surgery candidates.

According to the findings of the study, soft tissue complications were more prevalent in the lower extremity. This phenomenon can be associated with better perfusion in the upper extremity and the point that lower extremity traumas occur with more energy and this can be the reason for more severe soft tissue damage and the relevant complications.

Moreover, some complications like subcutaneous fluid collection, inflammation around the wound and dehiscence are more frequently observed in 1^st and 2^nd weeks while infection usually represents in 2^nd and 4^th weeks, preoperatively. In most cases, dehiscence represents up to the 2^nd week and since the wound tissue has a better consolidation, the incidence of the complication decreases. The case is the same with subcutaneous fluid collection and after the 2^nd week, the fluid is either absorbed or becomes infectious.

Based on the existing studies, the only case in which subcutaneous suturing is preferred is the use of subcuticular suture (plastic) or staple for skin repair [7-9]. In such conditions, subcutaneous suturing before skin repair leads to a more convenient, delicate and faster repair of the skin. In the study of Kore et al, the rate of complications due to not using subcutaneous suturing following abdominal hysterectomy of obese women is reported to be high. However, further investigations were not carried out to compare complications with the other group (with subcutaneous suturing) and to find the statistical significance [10]. In another study, the difference between two-layer and threelayer suturing in laparotomy was not significant [11]. Furthermore, following the study conducted on pilonidal sinus surgery candidates, simple skin suturing is an effective, inexpensive method [12].

Findings of the present study asserts that as no significant difference was observed in soft tissue complications of patients with and without subcutaneous suturing, it can be confidently said that the use of subcutaneous sutures did not have a specific effect on reducing complications like wound edge necrosis, a sign of the excessive tensin of skin; subcutaneous fluid collection, a sign of subcutaneous virtual space and other complications like dehiscence, wound infection and cutaneous reaction (inflammation). On the other hand, since subcutaneous suturing requires sufficient time, eliminating this technique can save the operation time and anesthesia and avoiding Vicryl can reduce the costs.