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Ventral incisional hernia

From Surgopaedia

Epidemiology

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  • Occurs in 11-20% of patients after laparotomy
  • Majority of these would be apparent by two years post-op
  • Accounts for 15-20% of all abdominal wall hernias

Risk factors

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  • Patient factors
    • Male gender
    • Obesity
    • Older age
    • OSA
    • COPD
    • Prostatism
    • Wound infection
    • Fascial dehiscence
    • Malnutrition
    • Ascites
    • Pregnancy
    • Diabetes
  • Operative factors
    • Oncologic resections
    • Large bites/poor technique

Pathophysiology

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  • Occur due to excessive tension or inadequate healing of a previous incision

Natural history

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  • Few long-term good-quality data
  • Enlarge over time

Presentation

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  • Examine standing and sitting
  • CT and USS are useful adjuncts
    • On CT, define the hernia as the distance between the rectus muscle bellies
  • Complications
    • Bowel obstruction
    • Incarceration
    • Strangulation
    • Loss of domain
      • See entry under 'hernia'

Pre-operative optimisation

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  • Smoking - almost absolute contraindication, double recurrence risk
  • Obesity with BMI > 40
    • BMI 50 gives an almost 100% recurrence rate - almost absolute contraindication
    • Ideally, get down to BMI 35, but <40 is acceptable
    • Bariatric surgery or GLP-1 agonists are valid techniques
  • Diabetes - target HbA1c <8.0%, ideally <7.0%
  • Nutrition
  • Skin condition
  • CT to define anatomy
    • Rectus:defect ratio (RDR) calculated by sum of right and left recti divided by defect width
    • RDR > 2: standard surgical repair
    • RDR < 1.5: component separation required in more than half
    • RDR < 1: component separation required in 80%
    • A defect 8-10cm wide is more likely to need advanced closure techniques
  • Prehab
    • Increase abdominal wall strength, weight loss, respiratory improvement
  • CeDAR app to calculate risks
  • Assess soft tissue coverage - may need flap
  • Botox
    • Blocks acetylcholine release from nerve terminals, causing chemical denervation
    • Can 'downstage' big hernias (been proven in hernias 12-18cm in size)
    • Reduces chance of needing component separation
    • 3 injections each side, total 100-150 units, laterally into each TA + IO + EO
    • Operate 2-4 weeks after injection
    • Gets 4-5cm muscle migration per side

Classification

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  • No current accepted simple mechanism for communicating complexity of a ventral incisional hernia
    • Incorporates defect size, location, loss of domain, patient comorbidities, presence of contamination, necessity for an ostomy, acuity of the presentation, history of prior repairs, and prostheses
  • Ventral Hernia Working Group grading scale
  • European Hernia Society classification


Management

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  • Principles
    • Optimise underlying causative factors
    • Re-create linea alba
    • Tension-free repair
  • Surgical considerations
    • Suture vs mesh
      • Mesh indicated >2-3cm or when the hernia was clearly a result of technical error at the primary operation
    • Mesh type
      • Permanent synthetic materials
      • Absorbable synthetic materials
      • Biologic materials
      • See separate topic under 'operating theatre'
    • Mesh placement
      • In general, IPOM and retro-rectus have lowest rates of recurrence, infection and seroma
      • Onlay
        • Primary closure of the defect and placement of mesh over the anterior fascia
        • Advantage - completely outside the abdominal cavity
        • Disadvantages - large subcutaneous dissection, increased likelihood of seroma, superficial location of the mesh, and the repair is usually under tension
        • Retrospective review - recurrence rate of 28%
        • Best to use midweight permanent synthetic mesh - polypropylene or polyester
      • Interposition
        • Secure the mesh to the fascial edge without overlap
        • Predictably high recurrence rate - mesh often pulls away from the fascial edge
      • Sublay
        • Prosthesis is placed beneath the fascia (intra-peritoneal, pre-peritoneal, or in the retro-rectus space)
        • Advantage - natural forces of abdomen hold the mesh in place and prevent migration
        • Intra-peritoneal
          • Composite or dual-type mesh placed below peritoneum with at least 4cm overlap
          • Secure with interrupted mattress sutures
          • Can be done laparoscopically - trocars as far laterally as possible, hernia reduced, adhesions lysed, mesh secured with trans-fascial sutures
          • Probably lower long-term recurrence rate if defect is also closed - meta-analysis 2024
        • Pre-peritoneal
        • Retro-rectus
    • Plan for tension-free closure
      • Progressive pneumoperitoneum (over a 3-week period) - particularly suited for small defects and massive sacs
      • Planned open abdomen with progressive closure of PTFE mesh as described under that separate topic - very morbid and time-consuming way to do it
      • Botox - see above under 'pre-op'
      • Tissue expanders
      • Fasciotens
      • Myofascial release/component separation
        • Allows advancement of rectus muscle by as much as 10cm from each side
        • Is component separation required? Which type?
          • Depends on ability to recreate the linea alba through medialisation of the rectus abdominis muscle while maintaining appropriate tension on the repair
          • Cameron's suggests do a posterior separation when possible, because it provides the benefit of myofascial advancement (as in anterior approach) but also allows wide mesh overlap in a sublay position between the abdominal musculature and the peritoneum while eliminating large skin flaps
          • Anterior release carries the disadvantage of often requiring large skin flaps with significant wound morbidity
        • Options
          • Posterior rectus sheath incision with retro-muscular mesh placement
            • Recurrence rate 14% in large incisional hernias
          • Posterior component separation
          • Anterior component separation
        • See separate topic for technique
      • 'Cytoreductive surgery' - omentectomy/colectomy
      • Other techniques described in SAGES manual of hernia repair
    • Open vs laparoscopic
      • Laparoscopic repair favoured if
        • Potentially more than one defect
        • High risk of SSI
        • High-risk for recurrence
        • Small or medium defect
      • Open favoured if
        • Many adhesions (need to clear for trocar placement and mesh placement)
        • Larger defects - hard to close laparoscopically
    • Drains
      • Probably don't need to routinely drain sublay repairs, even with retrorectus dissection - doesn't seem to affect seromas or infections
      • More role for drains in onlay repairs with big subcutaneous dissections
    • Recurrent hernias
      • Try to use a different plane - generally use pre-peritoneal for primary repair, then retro-rectus for next repair, and can either try again with retro-rectus or IPOM for the subsequent repair


Approach to open abdominal wall reconstruction

  • Midline incision through linea alba and reduction of hernia sacs
  • Attempt retro-rectus repair - if unable to close posterior sheath, consider component separation vs fasciotens

Operation

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  • Open retro-rectus repair
    • Midline incision
    • Reduce all hernia sacs, preferably without opening, down to pre-peritoneal plane
    • Enter the retro-rectus plane by incising from posterior at the level of the umbilicus, 1cm off midline. Find rectus muscle to confirm the correct plane.
    • Dissect along the entire length of the incision, moving laterally as far as linea semilunaris, confirmed by seeing the anterior and posterior sheath leaflets coming together. Don't injure nerves and vessels.
    • Join dissection planes cephalad and caudad. Leave the linea alba attached to anterior sheath.
    • Close posterior sheath with 2/0 Prolene (small stitch technique). If there is too much tension here, a posterior component separation is required to prevent posterior dehiscence and subsequent interstitial hernia.
  • Component separation/TAR
    • See separate topic
  • Suprapubic hernias
    • IDC
    • Vertical midline over hernia
    • Dissect out sac to pre-peritoneal plane, without entering sac
    • Dissect peritoneum from posterior sheath as a space for mesh (close any peritoneal defects made)
      • Allow 3-5cm mesh overlap of defect
    • Place mesh in plane. Inferior fixation can be a challenge - either sutures to pubis/Cooper's ligament, or bone anchor fixation
    • May need fasciotens to anterior sheath
  • Sub-xiphoid hernias
    • Pre-peritoneal plane is favoured, due to difficulty fixing mesh around xiphoid
  • Open repair of irreducible incisional hernia
    • Dissect onto sac
    • Open sac to examine for bowel strangulation
    • May need to increase size of defect to fully visualise
    • Resect as needed
    • Close defect - mesh if no contamination, as per inguinal hernia topic
  • Laparoscopic incisional hernia repair
    • Supine, with ports as lateral as possible
    • Take down adhesions until the hernia is visible and there is adequate surrounding landing zone - 5cm - consider conversion if very dense or if bowel is difficult to reduce
    • Reduce contents of sac, but leave the sac in situ
    • Close defect with v-lok suture
    • Place a circular mesh inside, orient it centrally, and tack it in place







Complications

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  • Mesh infection
    • Acute with sepsis - IV Abx, debridement and explant
    • Chronic - mesh salvage - antibiotic suppression and drainage of fluid collections. Follow-up CT to ensure resolution of fluid. Continued antibiotic suppression.
    • Refer to 'mesh' topic for guidance on specific types of mesh
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