Lumbar hernia

Anatomy/pathophysiology

• Lumbar region in general boundaries:
  • Superiorly 12th rib
  • Inferiorly iliac crest
  • Medially erector spinae
  • Laterally external oblique
• Lumbar hernias occur in either the superior or inferior lumbar triangle

Risk factors

• Inferior - more lateral insertion of external oblique and more medial insertion of latissimus dorsi into iliac crest, making the space bigger
• Superior - length and angle of the 12th rib, and size of quadratus lumborum and serratus posterior muscles. A short, obese person with more horizontal ribs is at risk.

Presentation

• 80% acquired
  • Primary (spontaneous)
    • Usually occur in superior lumbar space
    • Caused by conditions that increase intra-abdominal pressure - chronic cough, pregnancy, obesity
  • Secondary (trauma/incisional)
    • Often occur in inferior lumbar space - shearing force of weakened lumbar muscles against iliac crest
• 20% congenital
  • Generally appear in infancy
• Only about 10% will present in emergency, mostly elective

Workup

• CT scan best way to diagnose - 98% sensitivity

Management

• Generally need mesh coverage due to immobile bony margins
• Both open and laparoscopic possible, but both can be technically challenging
• Cameron's says laparoscopy should be preferred to open technique for initial repair
• Contraindications to laparoscopy:
  • Very large defect (>10-15cm)
  • Concern for bowel strangulation
  • Shock

Technique

• Open
  • Prone
  • Incise over mass, at least 2cm below 12th rib, parallel to intercostal nerves
  • Reduce sac, open if indicated
  • Invaginate sac with absorbable
  • Close transversalis fascia
  • Synthetic mesh secured to surrounding muscle layers
  • Cover mesh with overlying muscle
  • Larger defects may require rotational flap repair
• Laparoscopic
  • 45 degree decubitus position (see diagram below)
  • Umbilical entry
  • 5mm ports in ipsilateral upper and lower quadrants
  • Reduce sac, reapproximate muscle layers with transfascial suturing device
  • IPOM
    • 3-5cm mesh coverage
  • TAPP
    • Three-sided peritoneal flap raised starting 5-7cm anteriorly from the hernia defect

^rotational flap for inferior lumbar hernia using gluteal fascia