Skeletonized versus pedicled internal mammary artery: Impact of surgical technique on post CABG surgery pain

Objective: Recent evidence suggests that coronary artery bypass graft (CABG) surgery often results in chronic chest wall pain, termed: 'post CABG pain syndrome' (PCP). Direct injury to intercostal nerves during the surgical procedure was presumed to underlie this syndrome. The aim of this study was to investigate the effect of two harvesting techniques of the internal mammary artery (IMA) - skeletonization (S-LIMA) and pedicle (P-LIMA) on the occurrence and incidence of PCP. Methods: A mailed questionnaire enquiring about the presence and characteristics of PCP was sent to all 482 patients who had undergone CABG in our institution in the years 1999-2000. A randomly chosen subgroup of IMA patients reporting PCP were summoned for evaluations of pain localization and intensity, thermal and tactile sensitivity, and disability assessment using recognized tests and indices. Results: Of the 380 responders (S-LIMA: 221, P-LIMA: 125, veins only V-34) 169 (44%) reported having PCP. Its prevalence was similar between the two IMA groups (S-LIMA: 45%, P-LIMA: 50%) but significantly lower in the V group (18%, P=0.003). Physical assessment in the subgroup of 43 IMA patients (S-LIMA: 22, P-LIMA: 21) performed 40.2±8.7 months after surgery confirmed equal occurrence of mostly left and midline chest wall neuropathic pain in both IMA groups. No significant differences were found between the two groups in respect to indices of pain intensity, thermal and tactile sensitivity and disability. Conclusions: PCP is a prevalent finding in post CABG patients. The skeletonization technique of IMA harvesting although causing significantly less inner chest wall trauma does not appear to reduce the occurrence of PCP. This finding may imply that ischemic injury rather than direct mechanical injury to the intercostal nerves is the putative mechanism underlying PCP.