Effects of abdominal surgery through a midline incision on postoperative trunk flexion strength in patients with colorectal cancer

Background: Abdominal surgery with bowel resection through a midline or transverse incision is performed in most cases of colorectal cancer (CRC). Both incisions affect abdominal wall function and may lead to differences in postoperative clinical outcomes. Although postoperative isometric trunk flexion strength (ITFS) has previously been investigated, the results were based on measurement tools distinguished by poor reproducibility and validity. Objective: To evaluate the reproducibility of and variations in ITFS following abdominal surgery using a dynamometer and explore the correlation between ITFS and the scar length. Method: The study group consisted of 22 consecutive patients (15 men and 7 women) referred for surgery. The outcome parameters included ITFS which was measured using a fixed dynamometer and a digital manometer, scar length, weight and pain. Test-retest measurement (3 h apart) of ITFS was taken 1 day before surgery to determine the instruments' reproducibility. Additional measurements of the outcome parameters were taken 1 and 6 weeks postoperatively. Results: Excellent test-retest correlations (ICC > 0.85) coupled with low standard error of the measurement for both the ITFS and the manometric findings indicated clinically acceptable reproducibility of the findings. Significant pre- and postoperative differences in ITFS were noted using both techniques. Six weeks postoperatively, fair and significant correlations were noted between the dynamometry-based ITFS and both the scar length (r = 0.452) and age (r = 0.498). Of note, scar length and preoperative dynamometric ITFS predicted ITFS 6 weeks postoperatively (F = 102.949, p < 0.001, R² = 0.92). Conclusions: Measurements of ITFS using dynamometry in elective CRC patients are reproducible, sensitive to clinical changes and allow prediction of postoperative ITFS scores based on their preoperative counterparts.