Association between an improved positioning management strategy and non-incisional low back pain and sleep quality in patients undergoing modified radical mastectomy for breast cancer: a retrospective cohort study

Background Non-incisional low back pain, particularly low back pain, and sleep disturbance are common yet underrecognized problems during early recovery after breast cancer surgery. This study evaluated whether an improved positioning management strategy was associated with reduced non-incisional low back pain and improved postoperative sleep quality. Methods This single-center retrospective cohort study included adult women who underwent modified radical mastectomy or simple mastectomy for breast cancer between January 2024 and December 2025. Patients were grouped according to whether an improved positioning management strategy was implemented during the perioperative period (intervention vs. control). Non-incisional low back pain was assessed using the Numerical Rating Scale (NRS, 0–10), and sleep quality was assessed using the Richards–Campbell Sleep Questionnaire (RCSQ: 0–100) at 24, 48, and 72 h postoperatively. Safety outcomes included total drainage volume during the first 3 postoperative days, subcutaneous seroma, and skin-flap ischemia or necrosis. Linear mixed-effects models with random intercepts were used for repeated measures, adjusting for age, body mass index (BMI), analgesic regimen, and postoperative nausea and vomiting (PONV), with Holm correction for multiple comparisons. Gamma regression and Firth-penalized logistic regression were applied for safety outcomes. Results Baseline characteristics were generally comparable between groups, although BMI was slightly higher in the intervention group ( P = .04) and was adjusted for in multivariable analyses. Improved positioning management was associated with significantly lower non-incisional low back pain ( β = −0.711, P < .001). Pain increased over time in the control group, whereas significant group-by-time interactions indicated greater pain reduction in the intervention group at 48 h ( β = −0.358, P = .002) and 72 h ( β = −0.737, P < .001). Between-group differences in pain at all time points remained significant after Holm correction. The association remained significant after additional adjustment for incisional pain. Improved positioning management was also associated with higher postoperative sleep quality, with significant group and group-by-time effects at 24–72 h. No significant between-group differences were observed in drainage volume, seroma, or flap ischemia/necrosis. Conclusion An improved positioning management strategy was associated with reduced early postoperative non-incisional low back pain and better sleep quality after breast cancer surgery, without evidence of increased drainage- or flap-related complications. These findings should be interpreted as observational associations and warrant confirmation in prospective studies.