Perineal Hernia

Perineal hernia is protrusion of intra-abdominal or pelvic contents through a defect in the muscular pelvic floor (levator ani and coccygeus) into the perineum. It is rare. Fewer than 100 primary cases and a few hundred secondary cases have been reported in the literature.

Types by site: anterior (through the urogenital diaphragm, in women, lateral to the labia majora and bulging toward the vagina) and posterior (between the levator ani and coccygeus or through the ischiorectal fossa behind the transverse perineal muscle).

Causes

• Primary: middle-aged or older, multiparous women with weak pelvic floor, and some men with a deep pouch of Douglas
• Secondary (the majority): abdominoperineal resection of the rectum (incidence 1 to 7%), pelvic exenteration, proctectomy, hysterectomy, prostatectomy, pelvic radiotherapy, perineal wound infection or non-healing, and coccygectomy

Risk factors for secondary hernia are a wide pelvic floor resection, extralevator excision, omentum not interposed and perineal wound complications. Contents are small bowel, omentum, bladder, uterus or sigmoid colon. Complications: obstruction, strangulation, skin ulceration, urinary symptoms and recurrence after repair (up to 30%).

• A soft, reducible swelling in the perineum that appears on standing, coughing or straining and disappears when lying down
• Perineal heaviness or aching, discomfort when sitting, and difficulty with defecation or micturition
• Cough impulse over the swelling
• Obstructive symptoms or pain with tenderness if incarcerated
• Skin breakdown over the bulge in long-standing hernia
• Red flags: irreducible and tender swelling, vomiting, fever and skin necrosis

1. Clinical examination in the standing position with a Valsalva maneuver, with the patient in lithotomy position for assessment of the swelling.
2. CT or MRI of the pelvis is the investigation of choice: the defect in the pelvic floor, the sac and its contents, and the relation to pelvic organs.
3. Dynamic MRI or defecography shows the herniation during straining.
4. Ultrasound of the perineum detects contents in the sac.
5. Cystoscopy or urinalysis if the bladder is involved. Colonoscopy to exclude recurrent pelvic malignancy in secondary cases.

Differentials: rectocele, enterocele, ischiorectal abscess, perineal lipoma, Bartholin cyst, sciatic hernia, recurrent tumor.

1. Asymptomatic small hernias: observation, avoidance of straining, and treatment of chronic cough and constipation (macrogol 1 sachet orally once or twice daily).
2. Symptomatic or enlarging hernias: surgical repair, as there is no effective non-operative treatment.
3. Operative approaches:
   • Transabdominal (open or laparoscopic): reduce the sac, obliterate the pelvic space or close the defect with non-absorbable sutures, and place a mesh (synthetic polypropylene or biological) fixed to the sacral promontory, the pelvic sidewalls and the pubic bone. This is the preferred route in most patients, as it gives the best view of the defect.
   • Perineal approach: useful for small defects and in frail patients, with reduction and mesh placement or a layered closure.
   • Combined abdominoperineal approach for large or recurrent hernias.
   • Flap reconstruction: a vertical rectus abdominis myocutaneous flap or a gluteal flap to bring healthy tissue into the perineum, especially after radiotherapy or a large defect.
   • Biological mesh is preferred where there is contamination or fistula risk.
4. Prophylaxis: cefazolin 2 g IV 30 to 60 minutes before incision (3 g if over 120 kg), with metronidazole 500 mg IV if bowel is opened. Enoxaparin 40 mg SC once daily for 7 days.
5. Postoperative care: avoid heavy lifting for 6 to 8 weeks, treat constipation, and give paracetamol 1 g orally every 6 hours.
6. Complications: recurrence (10 to 30%), mesh infection, seroma, flap necrosis, bowel injury and chronic pain.

Follow-up at 2 weeks, 3 months and 12 months. Counsel on weight control and cough treatment.