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Internal Medicine

Incisional hernia

Abdominal wall hernia at the site of a previous surgical incision.

Introduction

Abdominal wall hernia at the site of a previous surgical incision.


Anatomy

European hernia society (EHS) classification | 2009:

Consensus classification of incisional hernia of the European Hernia Society (EHS) (2009) | Muysoms FE, Miserez M, Berrevoet F, et al. Classification of primary and incisional abdominal wall hernias. Hernia. 2009;13:407–414. | Muysoms F, Campanelli G, Champault GG, et al. EuraHS: the development of an international online platform for registration and outcome measurement of ventral abdominal wall hernia repair. Hernia. 2012;16:239–250.
  • Morphologically: Midline (M1–5) and lateral (L1–4, right or left) hernias
  • Location of midline hernias: Zones M1 to M5, based on the proximity of the hernia to the xiphoid process, umbilicus or symphysis pubis; a hernial orifice can extend over several areas, e.g. M1 to 3 or M3 to 5
  • Location of lateral hernias: Zones L1 to L4 and labelled according their side.
  • For the purpose of standardization, hernias are to be classified intraoperatively.
  • The size of the hernial orifice is measured in “length” and “width“. Since width is of particular prognostic relevance, the size of the hernial orifice is categorized according to width (W) in W1 (<4 cm), W2 (4–10 cm) or W3 (>10 cm).

Aetiology

Incisional hernias can occur after any abdominal surgical procedure where the abdominal wall is incised.

Incisional hernias develop because of the failure of the abdominal wall to close properly. Despite advancements in techniques for abdominal wall closure the incisional hernia rate following laparotomy is as high 15% to 20%.

Patient-related factors:

Impair proper wound healing and affect the strength of the new tissue to support the abdominal wall increase the incidence of incisional hernia.
  • Systemic chronic diseases: DM, renal failure, obesity, smoking, and malnutrition conditions
  • Systemic long-term medications: Steroids and immunosuppressants
  • Morbid obesity

Technical/disease risk-factors:

Related to the surgical technique or suture materials used for closure. Incision site, timing, and urgency of procedure, complications, and underlying diseases are associated with a higher incidence of incisional hernia development.
  • Emergency surgeries, midline incisions, infection, and acute abdominal surgeries
  • Postoperative wound infection (common risk factor)

Diagnosis

Imaging;

  • Computed tomography (CT): M/C used to diagnose and also useful in planning operative management
  • Dynamic Ultrasonography Assessment for Hernia-DASH
  • MRI
CT Abdomen Ventral Hernia. Contributed by Scott Dulebohn, MD

Management

Incisional hernia repair involves the use of a synthetic mesh and can be performed by conventional (open) surgery or minimally-invasive (laparoscopic) surgery.

Transverse section of the supraumbilical abdominal wall, showing relevant anatomical structures and mesh locations for incisional hernia repair. A) Releasing incision of the abdominal external oblique aponeurosis as part of the component separation technique described by Ramirez. B) Typical course of an intercostal nerve between the transversus abdominis muscle and the abdominal internal oblique muscle; the nerve enters at the lateral margin of the rectus sheath into the rectus abdominis muscle and gives off a cutaneous branch at its end. C) During transversus abdominis release (TAR) for positioning a mesh lateral to the rectus sheath, the course of this nerve has to be spared to prevent subsequent abdominal wall paralysis. D) With TAR, the mesh is placed between peritoneum and transversus abdominis muscle. E) Typical sublay mesh position (retromuscular). F) Underlay mesh position (preperitoneal). G) Intraperitoneal mesh position (IPOM = intraperitoneal onlay mesh). | Courtesy of Maren Hötten/Scientific Illustration
With retromuscular mesh repair of midline incisional hernia, it is crucial to ensure a mesh overlap extending underneath the xiphoid to prevent recurrence. A) Xiphoid process; B) Posterior rectus sheath closed in the midline. Due to the midline xiphoid process insertion of the rectus sheath, a so-called fatty triangle (D) is created during the release of the posterior rectus sheath from the xiphoid. At the end of the mesh repair, this triangle is only secured by the synthetic mesh (D). With proper dissection, the mesh overlap underneath the xiphoid process extends several centimeters in cranial direction. C) Anterior rectus sheath. (Courtesy of Maren Hötten/Scientific Illustration) | Dietz, U. A., Menzel, S., Lock, J., & Wiegering, A. (2018). The Treatment of Incisional Hernia. Deutsches Arzteblatt international, 115(3), 31–37. https://doi.org/10.3238/arztebl.2018.0031

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