Late sensory changes following chest drain insertion during thoracotomy

It is well known that chest drains are associated with severe movement-related acute pain. These noxious stimuli could play a significant role in development and maintenance of persistent post-operative pain. Therefore we studied chest drain sites in post-thoracotomy pain syndrome (PTPS) patients, in regard to pain and sensory dysfunction.

We quantified thermal and pressure thresholds on both the chest drain side and the contralateral side in 11 PTPS patients and 10 pain-free post-thoracotomy patients 33 months after the thoracotomy. On average, each patient had two chest drains inserted during surgery.

At follow up, two patients experienced pain at the chest drain sites, but had maximal pain near or at the thoracotomy scar. Comparison between chest drain side and control side for all 21 patients demonstrated significantly elevated thresholds for warmth detection and heat pain on the chest drain side (P < 0.01), but not for cool detection or pressure. No significant differences between chest drain side and control side were observed within PTPS or pain-free patients. Comparing PTPS and pain-free patients (chest drain-to-control side), no significant differences in thresholds were found. Although all 11 PTPS patients suffered from incisional pain, only two patients had pain from chest drains.

Increased thresholds for thermal detection suggest that chest drain insertion is associated with late nerve injury. Because no significant differences in sensory thresholds between PTPS and pain-free patients were found, the pathophysiological role of small fibre nerve injury from chest drains in relation to PTPS remains unclear.