What causes abdominal wall pain and incisional pain in an adult following a right lower lobe segmentectomy?

Abdominal Wall and Incisional Pain Following Right Lower Lobe Segmentectomy

Primary Causes

Postoperative incisional pain following thoracic surgery like right lower lobe segmentectomy is primarily caused by direct surgical trauma to the chest wall structures, including intercostal nerve injury, muscle disruption, and fascial tissue damage during the thoracotomy or thoracoscopic approach. 1

The pain mechanisms include:

• Cutaneous nerve root irritation from surgical incision through intercostal spaces, which can manifest as sharp, localized pain along the incision site 2
• Myofascial irritation from muscle retraction and tissue manipulation during the procedure, often presenting as diffuse discomfort that worsens with movement 2
• Structural tissue healing involving the chest wall layers (skin, subcutaneous tissue, muscle, and fascia) that were divided and subsequently closed 1

Temporal Pattern and Characteristics

Expected postoperative incisional pain should gradually improve over weeks to months; pain persisting beyond 3 months suggests chronic complications rather than normal healing. 1

Key distinguishing features:

• Acute postoperative pain (0-6 weeks): Expected inflammatory response to tissue trauma, typically responsive to analgesics and improving progressively 3
• Chronic pain (>3 months): May indicate nerve entrapment, neuroma formation, or other structural complications requiring specific evaluation 1, 2
• Posture-related pain: Pain that varies significantly with lying, sitting, or standing positions suggests abdominal/chest wall origin rather than visceral pathology 2

Specific Complications to Consider

If pain is localized with a palpable trigger point that remains tender or worsens when tensing the abdominal/chest wall muscles (positive Carnett's sign), the wall itself is the likely pain source. 2

Structural complications include:

• Incisional hernia: Occurs in 2-40% of major surgical incisions and can cause pain, discomfort, and potential serious sequelae like bowel obstruction 3
• Mesh-related complications (if mesh was used for closure): Foreign body reaction, mesh migration, or transfascial suture irritation causing prolonged pain 4, 5
• Nerve entrapment or neuroma: Intercostal nerves can become trapped in scar tissue or suture material, causing persistent neuropathic pain 1, 2

Diagnostic Approach

Examine for a localized tender trigger point; if tenderness is unchanged or increased when chest/abdominal wall muscles are tensed, the wall is the pain origin. 2

Specific examination findings:

• Carnett's sign: Have patient tense abdominal muscles by lifting head/shoulders; if pain increases or stays the same (rather than decreasing), this confirms wall origin 2
• Palpable defect: May indicate incisional hernia requiring imaging confirmation 3
• Radiation pattern: Pain may radiate diffusely despite localized trigger point 2

Management Strategy

For confirmed abdominal/chest wall pain without structural abnormality, injection of local anesthetic with or without corticosteroid into the trigger point is both diagnostic and therapeutic. 2

Treatment algorithm:

• First-line: Trigger point injection if hernia and structural disease are excluded 2
• If hernia suspected: Imaging (CT or ultrasound) to confirm diagnosis before surgical planning 3
• Persistent pain despite conservative measures: Consider surgical exploration for nerve entrapment, suture removal, or mesh revision if applicable 1, 5

Critical Pitfalls to Avoid

• Do not assume all postoperative pain is "normal healing" beyond 3 months; chronic pain requires specific evaluation for structural complications 1
• Do not overlook the chest/abdominal wall as pain source when visceral causes are excluded; wall pain is frequently missed 2
• Do not delay hernia evaluation if a palpable defect exists, as complications include bowel obstruction, incarceration, and strangulation requiring emergency intervention 3