Femoral hernia

Herniation through the femoral canal

Epidemiology

• 3% of all groin hernias
• Rare in men
• 10% of women and 50% of men who have a femoral hernia, have or will have an inguinal hernia
• 15-20% will strangulate

Anatomy/pathophysiology

• Mostly occur on right - attributed to tamponading effect of sigmoid colon on the left femoral canal
• See anatomy background under 'inguinal region'
• Can sometimes ascend to the inguinal canal after passing through the femoral canal - this is still technically a femoral hernia
  • Constrained by fascia lata superficially, so difficult to feel
  • Fascial attachments then prevent the sac from bulging downwards, so it bulges upwards, causing some confusion with inguinal hernias

Presentation

• Mass or bulge below the inguinal ligament

Differential diagnosis:

• Lipoma (pre-peritoneal fat in region)
• Lymphadenopathy - Cloquet's node, part of the deep inguinal chain
• It's actually very hard sometimes to distinguish between these three entities clinically - radiological diagnosis

Management

• Operation recommended due to risk of strangulation
• Principles
  • Reduce the hernia
  • Examine the contents of the sac for strangulation
  • Obliterate the defect in the femoral canal:
    • Approximate the iliopubic tract to Cooper ligament, OR
    • Place a prosthetic mesh (contraindicated in strangulation)
• Pitfalls
  • Not assessing the bowel, e.g. with spontaneous reduction on induction
  • Failure to check for replaced obturator artery

Choice of approach depends on experience of surgeon, and whether it's elective or emergency.

• Lockwood (infra-inguinal) if elective setting and low suspicion strangulated bowel. Doesn't disrupt femoral canal, but difficult to control the neck and a second incision might be required to reduce a strangulated hernia.
• Lotheissen (trans-inguinal) can handle both elective and emergent repairs, but disrupts the inguinal canal, leaving the patient at risk of inguinal hernia, especially in emergency setting.
• McEvedy (pre-peritoneal) approach (high) - best in emergency setting.
• Laparoscopic - see inguinal hernia

Modified McEvedy approach

• 10cm transverse incision - Langer's lines - midpoint overlying lateral edge of the rectus sheath, 4cm above the pubic tubercle (previously done through a vertical incision)
  • Original McEvedy was vertical skin incision
• Look out for superficial epigastric veins
• Open anterior rectus sheath vertically - just medial to linea semilunaris (can also open transverse if you want)
• Pass at lateral border of rectus muscle into pre-peritoneal plane - retract muscle medially, to get into TEP plane
• Expose underlying transversalis fascia and peritoneum (no posterior sheath as below arcuate line)
• Identify and ligate the inferior epigastric vessels
• Try to enter pre-peritoneal space and blunt dissect down to neck of hernia
  • Alternatively, enter peritoneum and reduce incarcerated viscera from within (combination internal and external force)
• Identify sac - reduce. If unable to reduce:
  • Gently dilate the neck of the hernia with a finger alongside the sac
  • Apply pressure externally and gentle traction from within
  • Consider dissecting the sac
  • Maybe divide lacunar ligament (medial), first checking that there is no corona mortis (common variant aberrant vascular anastomosis between external iliac artery (OR deep inferior epigastric artery) and the obturator artery. It runs along the deep border of the lacunar and pectineal ligaments, and is present in up to 30%.
    • Can divide inguinal ligament if necessary
    • Can also divide pectineal ligament posteriorly, but unlikely to get much more space as you are right on bone posteriorly anyway
• Open hernial sac and review bowel (can also open peritoneum posteriorly)
• Close orifice with vertical nylon or Prolene sutures between inguinalligament/iliopubic tract anteriorly and pectineal ligament (can also use polypropylene mesh plug)
• Re-approximate peritoneum and rectus sheath

Lockwood approach

• Incision inferior and parallel to inguinal ligament, immediately on top of the hernia
  • Can also use something like this approach through a normal IHR incision, then follow the EO down over the top of inguinal ligament and into femoral canal
• Dissect sac free from overlying tissue, isolating its neck
• Inspect sac and open if indicated (be careful of bladder as medial wall, if there's a sliding hernia)
  • Transfix and ligate if opening, then allow to retract
• Reduce
  • If incarcerated, relaxing incision may be made superiorly through inguinal ligament (tag ends with suture beforehand, so they can be repaired afterwards) or posteriorly into pectineal ligament
  • Best not to incise laterally (femoral vein) or medially (aberrant obturator artery, which you wouldn't be able to see from below). Won't make much space by incising posteriorly.
• Close ring with primary repair (or mesh plug if larger). Sutures between inguinal ligament and pectineal ligament.

Lotheissen

• Open transversalis fascia at the floor of the inguinal canal, between pubic tubercle and internal ring
• Dissect in pre-peritoneal space to neck of hernia
• Reduce using external pressure and internal traction
• Inspect sac
• Close femoral ring with mesh/suture
• Reapproximate inguinal ligament, probably reinforcing with mesh