Cost- Effectiveness and Cost-utility of Laparoscopic Versus Open Repair of Ventral Hernia
Condition: Hernia, Ventral
MeSH terms: Hernia; Hernia, Ventral
Study type: Interventional
Phase: Phase 4

Summary: 
      The purpose of this prospective paper is to make a comparison between laparoscopic and
      opening approaches in ventral hernia repair, taking into account absence of recurrence in
      long - time (5 years), results centered at patient, especially satisfaction with expectations
      and improvement of normal physical activity, morbidity that particular form must include
      chronic pain, adjusted mortality through co-morbidities and, finally, prospective expenses,
      related to both effectiveness and utility
    

Detailed description: 
      Population: 130 patients, diagnosed with clinic and radiologic (abdominal wall CT scan)
      ventral hernia, were recruited, after expressing their willingness, for either laparoscopic
      or laparotomy repair to be conducted at Infanta Elena Hospital, Huelva (Spain), between
      January 2005 and October 2008. Recruitment criteria were: patients above 18 years old,
      diagnosed with primary or incisional ventral hernia, including recurrent ones, featuring a
      prior-to-operation estimated size from 20 to 225 cm2. Exclusion criteria included type 4 or 5
      of ASA (American Society of Anesthesiologist), to suffer from a disease limiting lifespan to
      less than 2 years, cirrhotic ascites, emergency surgery or any complication as intestinal
      obstruction, strangulated hernia, peritonitis, local or systemic infection, failure of
      patient to ensure an at least 2 years follow-up or abandonment protocol. Every patient was
      fully informed and signed his willingness. Defect sizes were estimated and classified
      following Chevrel Classification. Patients were assigned a randomly generated number (see
      validated and published tables), meaning both laparoscopic or open repair, and informed same
      morning of operation. All operations were conducted by experienced surgeons. Protocol was
      approved by Local Ethics Committee.

      General techniques

      All patients were given an heparin prophylactic dose to prevent thromboembolic events evening
      prior to operation-day, as well as 1500 mg cefuroxime intravenous (IV) during anesthetic
      induction (in case of allergy, 600 mg of clindamycin IV + 80 mg of gentamicin IV). Also,
      evening before intervention-day all patients filled in survey (SF-36 questionnaire). Skin was
      prepared with an alcoholic solution of clorhexidine. Surgical pain was treated with magnesium
      metamizole (2gr IV each 6 hours). Upon patient request, 100 mg of tramadol IV was added (a
      maximum amount of 400 mg). Every patient was encouraged to hang around as soon as possible
      and be on a diet 8 hours after surgery, supplying oral treatment from then onwards. On
      discharge, patients were recommended wearing an abdominal binder for a month.

      Laparoscopic repair: Pneumoperitoneum was performed to 12 mmHg after placement first 12 mm
      trocar at level of umbilicus in anterior axillary line. Subsequently are placed two 5 mm
      auxiliary trocars. In all cases we explore entire abdominal wall for other defects not
      detected preoperatively. Herniary contents and sac are reduced releasing adhesions with
      diathermy or harmonic scalpel. Defects are repaired with a polytetrafluoroethylene (PTFE)
      patch (Dual Mesh; W.L Gore and Associates, FlagstaV, AZ USA) with double crown fixation as
      technique of Carbajo et al, ensuring exceed 3 cm edge of defect, using 5mm tackers (Protack,
      Autosuture; Tyco Healthcare, USA), reducing intrabdominal pressure to 8 mmHg. Not abdominal
      drainage was used. Skin was closed with metal staples. All operations were performed by
      experienced surgeons, over than 40 laparoscopic ventral hernia repairs.

      Open repair: Incision was made over hernia defect, reducing herniary contents by opening sac
      if it is necessary. We made 4 cm soft tissue flaps around edge of defect depending on
      available healthy fascial tissue. In all cases we use Chevrel technique with fascial closure
      using anterior rectus sheath with continuous and absorbable suture and placement of
      polypropylene mesh (Parietene, standart polypropylene mesh, Covidien, Norwalk, CT) in an
      onlay position fixed with polypropylene suture. We used one or two suction drains below
      subcutaneous flap which was sutured with absorbable suture, and metallic skin staples.

      Follow-up

      A given follow-up was always conducted by same researcher before hospital discharge, after 30
      days, 60 days, a year and once a year thereafter. All postoperative reports were analyzed
      with aim of finding protocol deviations or intraoperative complications. At hospital
      follow-up, before discharge, complications were actively looked (seroma, hematoma, wound
      infection, prolonged ileus, urinary retention and medical complications such as stroke,
      respiratory failure, arrhythmia, deep vein thrombosis, adverse drug reaction or pneumonia),
      hospital stay was achieved and onset of walking. Patient-centered outcomes analyzed were pain
      measured by visual analogue scale (VAS), addition to daily physical activity, analysis of
      quality of life related to health by surveys after 2 and 5 days (CVP-CG questionnaire) and
      difference between preoperative values, at 3 months and 12 months of physical and mental
      construct by survey (SF-36 questionnaire). At follow-up after discharge several facts were
      taken as exhibiting a satisfactory evolution, among them absence of hernia recurrence
      (defined as clinic examination and radiologic non-defect abdominal wall), absence of symptoms
      related to disability (chronic pain, intermittent ileus, trocar site hernia, fistula, abscess
      or prosthesis extrusion) and also absence of readmission or reoperation due to hernia repair.

      Cost analysis

      Expenses spent in ventral hernia repair were calculated from viewpoint of funder (health
      costs), taking into account only direct expenses and discarding indirect and intangible ones,
      as nearly all patients were economically assisted during convalescence period. Euro currency
      was used and a prospective approach to costs analysis was employed, following
      cost-opportunity method. As in-hospital expenses following variables were used materials,
      such as prosthesis, sutures, trocars, drainages and other surgical instruments; preoperative,
      anesthetics and postoperative medication (included recommended at discharge); operation room
      personnel cost and hospital wards; cost of diagnostic tests performed and consumption of
      hospitality. Installation costs, equipment inventoried and cost of warehousing and inventory
      management of consumables were neglected. As extra-hospital costs following items were
      included: personnel and materials used in medical visits and cures, drugs not prescribed,
      travel costs in medical transports, totality of which generated as a consequence of
      convalescence period (up to 60 days). Finally, expenses produced by a new hospital stay or
      reoperation because of complicated issues within two years after hernia repair were
      estimated, according to direct hospital costs at the beginning of study and further added to
      hospital expenses. As expenditure variable we use average patient cost.

      Statistical analysis

      A sample size of 130 patients was considered in order to detect differences in morbidity or
      an increase in hospital stays of 20%, assuming a type I error of 5%, powder of 80%, with
      losses of 10% and 2% crosslinking. To confirm normality Kolmogorov-Smirnov test was employed.
      Discrete variables are presented as percentage and confidence intervals of 95% and were
      compared through either Pearson test or Fisher exact test. Quantitative variables are
      depicted as mean values and standard deviations confidence intervals 95% using Student's t
      test. In all cases analysis was by intention of treat including in laparoscopic group those
      patients that required conversion to laparotomy. Also, an incremental cost-effectiveness
      analysis with confidence intervals of 95% was conducted, following Fieller theorem, and for
      sensibility analysis inversion cross-point was taken (threshold analysis). As efficiency
      measure a clinic profit analysis was carried out by means of a composite analysis that
      integrates absence of recurrence, readmission, reoperation or disability. As an indirect
      measure of utility is used values obtained from questionnaires (HRQOL -Health Related Quality
      Of Life), assuming standard mean response in case of SF-36 and mean response standardized by
      standard deviation of difference in case of CVP-CG instruments between two types of repairs
      as well as effect size between preoperative value and postoperative one in case of SF-36.
      choice of measurement of HRQOL as a measure of utility was made under requirement that in
      absence of clinically relevant differences in mortality, recurrence or morbidity, a
      clinically relevant difference in HRQOL is a preference by patient and thus a choice between
      treatment alternatives. A minimum significance level of 0.05 was assumed. Every analysis was
      conducted by blinded statistician through statistical package (SPSS statistical program,
      version 11.5, SPSS Inc, Chicago).
    

Intervention name(s): Laparoscopic ventral hernia repair
Intervention type(s): Procedure
Intervention description(s): Intraperitoneal ventral hernia repair with the use of Gore-tex Patch
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Health Services Research