Why does a patient develop burning-type lower abdominal pain following robotic inguinal hernia repair?

Burning Lower Abdominal Pain After Robotic Inguinal Hernia Repair

Burning-type lower abdominal pain after robotic inguinal hernia repair is most commonly caused by nerve injury or entrapment of the ilioinguinal, iliohypogastric, or genitofemoral nerves during the surgical procedure. 1

Primary Mechanism: Nerve Injury

The diagnostic triad of postoperative nerve entrapment comprises:

• Typical burning or lancinating pain near the incision that radiates to the area supplied by the nerve 1
• Clear evidence of impaired sensory perception in the distribution of the affected nerve 1
• Pain relieved by infiltration with local anesthetic at the site where the ilioinguinal and iliohypogastric nerves exit the internal oblique muscle 1

The ilioinguinal nerve is at the greatest risk of entrapment during mesh placement, regardless of whether the approach is open or robotic. 2

Clinical Presentation Pattern

Sensory disturbances occur in approximately 34% of patients after open inguinal hernia repair, though the incidence may differ with robotic approaches. 3 These sensory changes include:

• Burning pain radiating from the incision to the groin, scrotum, or upper thigh 1
• Numbness or altered sensation in the distribution of the affected nerve 4
• Pain that may be mild at rest but worsens with movement or exercise 2

Timing and Severity

Chronic postoperative inguinal pain can affect up to 50% of patients after hernia repair, though most experience mild to moderate pain rather than severe symptoms. 4 The pain typically:

• Manifests immediately postoperatively or develops within weeks 1
• May persist for months if nerve injury occurred 1, 2
• Interferes with normal daily activities in a significant proportion of patients 2

Critical Assessment Steps

When evaluating burning abdominal pain after robotic hernia repair, immediately assess for:

• Tachycardia ≥110 bpm, which is the single most important early warning sign of postoperative complications 5
• Fever ≥38°C, hypotension, or respiratory distress suggesting infection or other serious complications 5
• Development of peritoneal signs (guarding, rigidity, rebound tenderness) necessitating prompt diagnostic evaluation 5

Diagnostic Workup

If the pain is purely neuropathic (burning, radiating, with sensory changes) without systemic signs:

• Perform sensory testing in the distribution of the ilioinguinal, iliohypogastric, and genitofemoral nerves 1, 3
• Consider diagnostic nerve block with local anesthetic at the point where nerves exit the internal oblique muscle 1
• Relief of pain with nerve block confirms the diagnosis of nerve entrapment 1

However, if tachycardia, fever, or peritoneal signs are present:

• Obtain contrast-enhanced CT abdomen/pelvis immediately, which has 88-94% sensitivity for serious complications 5, 6
• Simultaneously obtain CBC, comprehensive metabolic panel, and lactate 5
• Do not dismiss tachycardia as "normal postoperative" when accompanied by persistent pain 5

Common Pitfall to Avoid

Never assume burning pain is simply "normal postoperative pain" without ruling out serious complications first. While nerve injury is the most common cause of burning pain, serious complications like bowel injury, mesh infection, or vascular compromise can present with similar symptoms initially. 5 The combination of burning pain with tachycardia, even without fever, warrants immediate imaging. 5

Treatment Approach

For confirmed neuropathic pain from nerve injury:

• Surgical neurectomy (resection of the compromised nerve) is the most effective treatment, with 16 of 23 patients (70%) becoming symptom-free in one series 1
• Conservative management with neuropathic pain medications (gabapentin, pregabalin) can be attempted first 4
• Repeat nerve blocks may provide temporary relief but do not address the underlying entrapment 1

Prophylactic neurectomy during the initial hernia repair decreases chronic groin pain incidence, though the difference is not statistically significant. 2 The decision to preserve versus excise nerves during surgery remains controversial, as both approaches carry risks of chronic pain. 4, 7