Objective: To investigate the presence of widespread pressure pain sensitivity in cancer patients following partial colorectal resection in the abdominal and lower back area and to describe the presence of abnormalities in abdominal and lower back muscle morphology.
Methods: Twenty colon cancer survivors (eight females, mean age 56.60 ± 7.76 years) and 20 matched healthy controls (10 females, mean age 54.22 ± 8.12 years) participated. Abdominal and lower back pain was assessed after undergoing surgery using a Visual Analogue Scale (VAS) and Brief Pain Inventory (BPI). Pressure pain thresholds (PPTs) were bilaterally assessed over the supraumbilical, infraumbilical, and lower back areas and the second metacarpal. Ultrasound imaging was used to measure the depth of the abdominal muscles, the width of the midline abdominal fascia and the width of the lumbar multifidus.
Results: Ten months after finishing oncological treatments, patients who underwent partial colorectal resection reported significantly higher pain levels in the low-back area (P = 0.003) but not in the abdominal area (P = 0.426) compared with the matched controls. After surgery, the colon patients reported significantly higher BPI-intensity (P < 0.001) and BPI-interference scores (P = 0.009) compared with the matched controls. An analysis of variance (ANOVA) revealed significant between-groups difference in dominant-side lumbar, supraumbilical and infraumbilical (P ≥ 0.01), and second-metacarpal (P < 0.05) PPT levels. A significant between-groups difference was found by the ANOVA in ultrasound imaging of the depth of the internal oblique muscle (F = 4.887, P = 0.035) but not in the other ultrasound imaging measurements.
Conclusions: Ten months after oncology treatment, colon cancer survivors show widespread pressure pain muscle hyperalgesia and reduced depths of dominant-side internal oblique muscles compared with matched controls.
Keywords: Abdominal Muscles; Colon; Neoplasm; Pain; Ultrasound.
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