Repair of Large Incisional Hernias - To Drain or Not to Drain Randomised Clinical Trial
Condition: Ventral Hernia
MeSH terms: Hernia; Incisional Hernia; Hernia, Ventral
Study type: Interventional
Phase: Phase 2

Summary: 
      The aim of this study was to perform a randomised clinical trial comparing the use of
      closed-suction tubular drains and progressive tension sutures in individuals with large
      incisional hernias subjected to onlay mesh repair to evaluate the occurrence of seroma and
      surgical wound infection after surgery.
    

Detailed description: 
      The present randomised clinical trial was approved by the research ethics committees of the
      São Paulo School of Medicine - Federal University of São Paulo (Universidade Federal de São
      Paulo - UNIFESP), the State University of Western Paraná (Universidade Estadual do Oeste do
      Paraná - UNIOESTE) and the University Hospital of Western Paraná (Hospital Universitário do
      Oeste do Paraná - HUOP) in compliance with the 1964 Declaration of Helsinki and later
      updates.

      The study design and randomisation followed the Consolidated Standards of Reporting Trials
      (CONSORT) version 2010 15.

      All the participants read and signed an informed consent form at the preoperative assessment
      visit.

      Inclusion and exclusion criteria Individuals with primary or recurrent incisional hernia were
      assessed at HUOP, and those with longitudinal or transverse ventral hernia secondary to a
      previous surgical incision, measuring 5 to 15 cm after dissection of the hernial sac and
      classified as large or very large according to Chevrel's classification, were considered to
      be eligible16. In individuals with multiple defects, the length between the cranial margin of
      the most cranial defect and the caudal margin of the most caudal defect was considered17.
      Individuals subjected to emergency surgery, with infection, immunosuppressed, younger than 18
      or older than 80 years old, ASA III or IV, with a serum albumin concentration lower than 3.0
      g/dl or who refused participation were excluded from the study.

      Surgical technique The participants were admitted to the hospital the night before surgery to
      perform or update the assessment of their surgical risk according to the American Society of
      Anesthesiologists (ASA) criteria, as well as for measurement of the serum albumin
      concentration.

      Incisional herniorrhaphy surgery was performed following the group's technique
      systematisation by a resident physician supervised by one of four surgeons professors at the
      medical course of UNIOESTE and who the using the onlay technique as described by
      Chevrel18-20. Antibiotic prophylaxis was performed with a single 2 g dose of cefazolin at the
      time of anaesthetic induction followed by a booster 1 g dose when the surgery lasted more
      than three hours.

      The aponeurosis was dissected 5 cm beyond the aponeurotic defect. Approximation of the
      aponeurotic margins for midline reconstruction was performed using polyglactin 910 #1
      sutures. Tension was relieved by releasing incisions performed on the external oblique muscle
      aponeurosis, 3 cm away from the linea alba, as described by Gibson21. A macroporous
      polypropylene monofilament P1 mesh of 100 g/m2 (Cousin Biotec) was fixed on the aponeurosis
      by separate 2-0 polypropylene sutures performed every 2 cm.

      The participants were randomised immediately after mesh fixation by a computer-based random
      number generator and allocated to the two intervention groups.

      Interventions In group 1, a 4.8 mm diameter continuous closed-suction tubular drain (Medsharp
      Ind.Com.Prod.Hosp.Ltda - reg. MS (Ministério da Saúde [Health Ministry registry]):
      80267170001) was placed between the aponeurosis and the subcutaneous tissue caudally to the
      incision. Next, the subcutaneous tissue approximation was performed with separate absorbable
      polyglactin 910 2/0 sutures.

      Drains were not used in group 2, but separate absorbable polyglactin 920 2/0 sutures were
      placed from the subcutaneous mesh to the aponeurosis every 2 cm by means of the progressive
      tension suture (or Quilting Sutures) technique, as described by Pollock et al.10-13.

      Skin closure was performed with simple separate sutures at 1 cm intervals using nylon
      monofilament suture #4-0 in both groups. The participants were requested to use the support
      girdles provided by the surgical staff at the hospital and at home during the first 30 days
      after surgery.

      In group 1, the drains were removed when the drained volume was less than 40 ml/24 hours.

      Outcomes All the participants were clinically assessed by the attending staff to detect
      postoperative complications, seroma formation and surgical site infection, especially on
      postoperative (PO) days one, three, five, seven, 14-16 and 29-31. The data were recorded on a
      pre-established form.

      All the participants were subjected to abdominal wall ultrasound to assess seroma formation
      at three time points defined as: early (PO days four to six), intermediate (PO days 14 to 16)
      and late (PO days 29 to 31). The tests were performed by the radiology staff at HUOP. Seroma
      was defined as the collection of any volume of subcutaneous fluid without debris. All the
      participants remained in the hospital until the first ultrasound assessment was performed.
      The presence of seroma was considered as the main outcome. Clinical seroma was defined as a
      visible bulge or fluctuation without signs of infection, subclinical seroma was defined as
      the absence of detectable abnormalities on physical examination but the presence of any
      volume of fluid collection on abdominal wall ultrasound, and seroma was defined as all
      occurrences of fluid collection detected on ultrasound.

      Surgical wound infection was prospectively defined according to the criteria formulated by
      the Centers for Disease Control and Prevention (CDC) in the Guideline for Prevention of
      Surgical Site Infection, 1999 22.

      Sample size calculation The sample size was calculated based on significance level alpha = 5%
      and 80% power. A two-tailed test for the comparison of the two proportions was used to
      compare the occurrence of seroma between the groups with drains (50.0%) or progressive
      tension sutures (10.0%)

      Statistics The initial statistical analysis of all the data collected in the present study
      was descriptive. In regard to the quantitative (numerical) variables, summary measures
      including mean, standard deviation, median, maximum and minimum values were calculated, and
      one-dimensional scatterplots were constructed. The data corresponding to the qualitative
      (categorical) variables were assessed as absolute and relative (percent) frequencies.

      Inferential analysis was performed to confirm or refute the evidence found in the descriptive
      analysis. For that purpose, Student's t-test for independent samples was used to compare the
      groups of participants.

      In the inferential analysis, the significance level (α) was established as 5%. The
      statistical analyses were performed using software R version 2.15.2.
    

Intervention name(s): Drain; Progressive Tension Sutures
Intervention type(s): Procedure; Procedure
Intervention description(s): In group 1, a 4.8 mm diameter continuous closed-suction tubular drain (Medsharp Ind.Com.Prod.Hosp.Ltda - reg. MS (Ministério da Saúde [Health Ministry registry]): 80267170001) was placed between the aponeurosis and the subcutaneous tissue caudally to the incision.; Drains were not used in group 2, but separate absorbable polyglactin 920 2/0 sutures were placed from the subcutaneous mesh to the aponeurosis every 2 cm by means of the progressive tension suture (or Quilting Sutures) technique, as described by Pollock et al
Other intervention name(s): 4.8 mm diameter surgical closed-suction tubular drain; Quilting Sutures, Baroudi Sutures
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: ventral hernia; seroma; drainage; infection