Burst abdomen. A preventable complication, monolayer closure of the abdominal incision with monofilament nylon.
Burst abdomen is a serious postoperative complication that concerns every abdominal surgeon. The incidence of this complication as reported from two hospitals from India, viz., from Delhi and Surat was 5 and 7% respectively. Efforts have been made to overcome this complication with various inovations in the technique of closure of laparotomy incisions and use of different types of suture materials.
Though the multilayer closure of laparotomy wounds with catgut has been the standard practice, it is accompanied by a high rate of wound dehiscence (3.88 to 14%).,
The recent experimental and clinical studies have reported a significant reduction in the incidence of burst abdomen by using a single layer closure of laparotomy incisions with a non-absorbable suture material. The incidence of burst abdomen with this technique varies from 0 to 0.9%.,,,,
The purpose of the present study was to assess the efficacy of a single layer closure of laparotomy incisions with interrupted monofilament nylon No. 1 suture (Modified Jenkin's technique) in the prevention of burst abdomen.
The present study was carried out over a period of 3 years from January 1978 to January 1981 and includes 100 patients operated by the author for various intra abdominal conditions.
Both emergency and routine cases were included and there was no patient selection. The patients were particularly scrutinized for the presence of factors responsible for delayed wound healing and burst abdomen, i.e. nutritional status, anaemia, hypoproteinaemia, pre- and postoperative prolonged steroid therapy, peritonitis, malignancy, presence of jaundice, uraemia, prolonged post-operative abdominal distension and persistent cough. Such cases were included in the high risk group for developing burst abdomen.
Post-operatively, each patient was examined for the presence or absence of any wound infection, extrusion of suture ends, sinus formation and development of burst abdomen. The diagnosis of burst abdomen was made when all the abdominal layers gave way.
After completion of intraperitoneal procedure the parietal peritoneum, posterior rectus sheath, and the anterior rectus sheath all were approximated by a single layer of interrupted sutures of No. `1' monofilament nylon, mounted on a large half circle, cutting needle. Each suture was placed 1.5 to 2 cm away from the wound edge on either side, at an interval of about 1 cm from each other. In the case of paramedian incision, rectus muscle was not included within the suture bite. To achieve this, while passing suture through the lateral cut edge of the incision, first the peritoneum and the posterior rectus sheath were pierced, then the medial border of the muscle was displaced laterally with the curve of the needle, before finally passing the suture through the anterior rectus sheath. The knots were tied by tripple layer of double throw of the suture and the ends were cut flush with the knots. While sutures were being tied, the abdominal contents were protected by a maleable retractor. Usually there is some difficulty in inserting the last suture at the lower end of the wound. To overcome this difficulty, I have recently started inserting the last suture in the central part of the incision. To avoid injury to the underlying viscera while applying the last suture, the ends of the sutures applied just above and below the last one are kept long and by applying traction to them, the abdominal wall gets lifted away from the underlying viscera.
The skin was closed as a separate layer with cotton or silk sutures.
There were 100 patients, 65 males and 35 females. The age varied from 6 to 62 years with 45 patients under 40 years and 55 over 40 years of age. Twenty-nine patients were operated as elective cases, while 71 underwent an emergency laparotomy. Majority of the cases were explored through a right paramedian incision [Table - 1].
[Table - 2] shows the distribution of cases according to diagnosis.
Seventy-five per cent of the patients belonged to high risk group for the development of the burst abdomen. [Table - 3] shows the list of predisposing causes present in these patients.
None of the patients developed burst abdomen. Superficial wound infection was noticed in 10 cases. However, in all of them the wounds healed in due course of time, without requiring removal of the nylon sutures. Wound discomfort or extrusion of cut ends of the sutures was absent in all the cases.
It is very much within the means of a surgeon to prevent the development of burst abdomen from taking place, even in the presence of predisposing factors responsible for poor wound healing (e.g. poor nutrition, cirrhosis of liver, uraemia, prolonged steroid therapy, infection and malignancy) and cutting through of suture material (post-operative paralytic ileus, and persistent cough).
A marked reduction in the incidence of burst abdomen can be achieved by utilizing a proper suture material and by employing a correct technique of abdominal closure., , 
A suture material to be labelled as near-ideal for abdominal closure should have the following properties:
(a) It should have excellent handling and knotting properties.
(b) It should not fray and should slide through the tissues readily.
(c) It should be non-irritant and should not provide nidus for infection.
(d) It should neither disappear nor lose its tensile strength until the wound has regained near-normal tensile strength.
(e) It should not cause discomfort to the patient.
From the above criteria, chromic catgut suture appears highly unsatisfactory for closure of laparotomy incisions. It loses its tensile strength very fast and little is left after 8-9 days. It gets prematurely absorbed and its knot holding capacity is unreliable.,  These drawbacks of catgut suture can be overcome by the use of non-absorbable suture material., ,  In the present study, monofilament nylon has been used as it fulfills almost all the criteria to be an ideal suture material for closure of abdominal incisions., 
Only 16% of tensile strength of the nylon is lost after one year. Being monofilament unlike braided material it does not harbour bacteria. Even if the wound gets infected, healing does take place without the need to remove the suture material. In the present series also, though 10% of the cases developed wound infection, none required removal of the suture material.
Though slipping of the knot with monofilament nylon has been reported by Herrmann et al (1970) and Shukla et al (1981), it was not experienced in this series, mainly because of the use of triple layer of double throws for tying the knots. This technique of knotting also obviates the need to keep the cut ends long (a potent cause of wound discomfort and extrusion of suture ends). In this study, even very thin patients did not complain of any wound discomfort or extrusion of cut ends through the skin as sutures were cut flush with the knots.
A, No. '1' monofilament nylon was used, as a heavy grade of suture material reduces the tendency of the stitch to cut through the tissues. Dudley (1970) observed that the pressure per unit area exerted on the tissues and hence the tendency to cut out is inversely proportional to the diameter of the suture material.
Mass closure of the abdominal wall (under the skin) avoids the cutting through of intact suture, the latter being an important cause of burst abdomen. Dudley (1970) observed that the distribution of forces at the suture tissue interface and therefore tendency to cut through is inversely proportional to the size of the tissue bite. In the single layer closure technique in this study, as each bite was taken 1.5 to 2 cm from the wound edges, it included a large bulk of tissue, hence there was no incidence of cutting through of the suture. Moreover, even if some cutting of tissue by the suture still occurs, the mass of the tissue is enough that healing is complete before the process of cutting is over. Leaper et al proved by their experiments on cadavers that a deep bite taken more than 1 cm from the cut edge is twice as secure as a bite of 0.5 cm from the cut edges.
In layer closure technique, relatively smaller quantity of tissue held by each stitch provides less resistance to cutting out of sutures. Experimentally, it has been proved that the mean suture holding capacity of the anterior rectus sheath alone is just over half that of full thickness of the peritoneum, muscle and the aponeurosis., 
The interrupted sutures were preferred over continuous sutures in the present study, as it was feared that continuous mass suture might produce strangulation of the tissues included in the bite. Though Jenkin (1976) has used continuous sutures with good results, he has recommended that a ratio of about 4:1 between the length of the suture material and the wound length should be maintained to avoid strangulation of the tissues.
There was zero per cent incidence of burst abdomen in the present series despite the presence of predisposing factors in majority of the cases [Table - 3]. The type of surgery, the basic disease, type of incision and age and sex of the patient did not affect the results. This could be achieved as a result of the use of monofilament nylon No. 1 as suture material and employment of the technique of single layer closure for all laparotomy incisions. Similar low incidence of burst abdomen has been reported by others using this technique , , ,  [Table - 4].