Evaluation of Double Mesh Modification of Chevrel’s Technique in Management of Midline Incisional Hernia

Background: Chevrel’s technique provides tensionfree repair of midline incisional hernia, but wide skin and subcutaneous dissection increases rate of complications. Here, we evaluate the double mesh modification of Chevrel’s technique in midline incisional hernia repair. Methods: 22 patients with midline incisional hernia underwent double mesh modification of Chevrel’s technique. After excision of hernial sac with minimal dissection of the skin and subcutaneous tissue, the anterior rectus sheath is incised on both sides to create medial flaps that are sutured to each other. Both recti abdominis muscles were dissected off the posterior rectus sheath, opening the retrorectus space. Prolene mesh was fixed in the retrorectus space with prolene sutures, and tailored to cover the bare area of anterior surface of both recti muscles and fixed to the lateral flaps of the anterior rectus sheath with interrupted prolene sutures. Results: We observed no recurrences, no skin necrosis, two cases of seroma, one case of superficial wound infection and one case of temporary chronic pain. Conclusion: Double mesh modification of Chevrel technique is an efficient method for treatment of midline incisional hernia, with minimal surgical site occurrences.

Chevrel's technique entails dissecting the skin and subcutaneous tissue beyond the lateral border of the anterior rectus sheath, increasing the risk of skin necrosis and seroma formation (15). Our modification of Chevrel's technique offers tensionfree repair of midline incisional hernia without farlateral dissection of skin and subcutaneous tissue, decreasing the rate of skin necrosis and recurrence.

Methods
This study is a clinical trial carried out between January 2017 and December 2018 on 22 patients with midline incisional hernia. Hernioplasty was performed using the double mesh modification of Chevrel's technique, and all the procedures were performed by the same group of surgeons. The objective of this study was to evaluate the efficacy of double mesh modification of Chevrel's technique in treatment of midline incisional hernia. The primary outcome of this study was hernia recurrence (detected by clinical and abdominal wall ultrasound examination), and necrosis of the midline wound edges (detected by clinical examination). Seroma, wound infection, and chronic pain, corsage feeling were considered secondary outcomes. Follow-up was carried out in outpatient clinic visits by a working team member, one week after discharge, after 3 months, and later every 6 months. Exclusion criteria were American Society of Anesthesiologists (ASA) physical status class 3 and 4, inflammatory bowel disease, urgent settings recurrences and previous abdominal neoplasms with high risk of local recurrence (rectal cancer) and pediatric patients. Written informed consent was obtained from all patients participating in the study. The study was approved by the institutional review board and the ethical committee of our university hospital. Also, the study is registered in clinical trials under identifier number NCT04166201. We report no conflict of interest. All patients received an intravenous antibiotic prophylaxis with subcutaneous administration of fractionated heparin before surgery, when indicated.

Surgical technique
All patients were operated on with the double mesh modification of Chevrel's technique. The previous scar was excised, next the subcutaneous space was dissected deep into the neck of the hernia but was not wider than 1 cm from the edges of the defect. The sac was then opened and resected, the defect size was measured, the skin and subcutaneous tissue were dissected off the anterior rectus sheath, allowing only dissection of an anterior rectus sheath flap just sufficient to close the defect without tension ( Figure 1). Next, a bilateral longitudinal incision was made on the anterior surface of the anterior rectus sheath and a medial anterior rectus sheath flap was dissected off the rectus abdominis muscle. Both recti muscles were dissected off the posterior rectus sheath opening the retrorectus space, and each of the medial anterior rectus sheath flaps was sutured to its fellow of the other side with slow absorbed sutures, closing the defect without any tension and reforming the posterior rectus sheath (Figures 2 and 3). A sizable prolene mesh was fixed with prolene sutures in the retrorectus space spreading between lateral ends of the space, and tunneled up 4 cm in the retrorectus space far from vertical edges of the defect (Figure 4). The anterior rectus sheath was closed using a prolene mesh tailored to the size of the space between the lateral flaps of both sides and sutured to the edges of the lateral flaps with interrupted non-absorbable sutures ( Figure 5). Figure 6 illustrates the whole technique. A suction drain is left in site, subcutaneous tissue is closed with Vicryl (3\0), skin is closed with prolene (3\0), and drain is removed when the amount of drainage is below 30 mL/ day. All patient data including demographic data, preoperative investigations, operative findings such as defect size, operative time, and follow up data such as early postoperative findings (skin edges viability, wound infection, seroma and early hernia recurrence), and late postoperative findings (late hernia recurrence), were extracted. These data were analyzed using SPSS v22.

Results
This study recruited 22 patients with midline incisional hernia (Figures 7 and 8, before and after repair), who all underwent double mesh modification of Chevrel's technique. The mean age of patients was 52.36±SD 8.7 years, 12 were male and 10 female, and BMI mean 30.1±SD 2.8. Two patients were diabetic and two were receiving anticoagulant therapy. Table 1 presents their demographic data and associated diseases. The intraoperative findings (defect size and multiple defects encountered during surgery) are in Table 2. The sizes of defects ranged between 2.5 cm and 13 cm, the mean diameter was 8.4 cm±SD=2.8 cm. Multiple defects were found in 8 patients, dermolipectomy was done on 3 patients, and the operative time ranged between 95 minutes and 140 minutes, with mean time 110.5±SD 10.7. The follow-up period ranged between 7 and 31 months, with mean follow up time 23.4±7.8 months. By this period there was no recurrence or skin necrosis but we encountered seroma in two patients, which resolved within 2 weeks after two times aspiration and suction drain removal. Superficial wound infection occurred in one patient which resolved with conservative measures, while chronic pain occurred in one patient and disappeared after 6 months, and corsage feeling occurred in one patient and disappeared after 5 months (Table 3).

Discussion
Incisional hernia may be a very serious and disabling disease. Its treatment is also challenging because improper surgery may imply a high recurrence rate (up to 50%), with unacceptable morbidity and mortality (7,(8)(9) (20) reported skin necrosis in 4% of patients. In this study there was no skin flap necrosis; this may be due to the minimal dissection of the skin and subcutaneous tissue from the anterior rectus sheath, thus preserving blood vessels supplying the skin.

Conclusion
The double mesh modification of Chevrel's technique offers an efficient, tension-free repair with a low complication rate for treatment of midline incisional hernia.