Abstract
Continuous and uncontrolled wound pain frequently follows open heart surgery (median
sternotomy). The authors investigated pain origins with x-ray computed tomography
(CT). The assessment included 34 patients (29 males, 5 females, mean age 57 years)
who underwent open heart surgery. All received unenhanced CT scans in horizontal 5
mm segments from the upper margin of the aortic arch to the diaphragm. Sternum alignment
was measured on the horizontal sections. The maximum slide (mm) and number of slippage
sections determined the severity of misalignment. Patients had postoperative wound
pain duration (months) measurements and were grouped by an analogic pain scale three
months after surgery: group 1, no pain or only slightly painful; group 2, ranging
through painful, very painful, and unbearably painful. All received chest x-rays,
Holter ECGs, stress ECGs and echocardiograms. Pain originating from angina pectoris,
pericardial effusion or pleural effusion was excluded in all patients. Sternums were
transfixed by 5 metal wires, and sternum cross-sections were clearly visible on the
CT scans. Although no sternum separations existed, 29 of 34 patients had misalignments.
The average vertical misalignment measured 5.5 ± 3.6 mm (maximum 11 mm) with the average
number of CT sections with misalignments being 21.2 ± 9.5. The duration of post-operative
pain was much longer for the 29 patients with misalignments than the 5 without misalignments
(17.2 ± 6.2 months and 3.9 ± 2.5 months, respectively, p < 0.01). The analogic pain
scale included 15 in group 1, and 19 in group 2. The average misalignment was larger
in group 2 than in group 1 (6.4 ± 2.1 mm and 3.1 ± 1.8 mm, respectively, p < 0.01).
CT scans clearly visualize sternum cross-sections. The authors' results suggest that
wound pain after open heart surgery (median sternotomy) is directly linked to sternum
misalignments.
