Impact of prior hysterectomy on risk of subsequent back injury in front line healthcare workers

Abstract

Low back injury (LBI) is associated with altered core muscle function and studies have validated the role of these deep stabilizing muscles in prevention and treatment of back pain and injury. No previous studies have evaluated the impact of surgery such as abdominal hysterectomy (AH) on these deep stabilizers and the potential for increased risk of LBI following surgery. The aims of this research were to investigate a link between AH and LBI first with administrative health data analysis and then clinically by measuring muscle thickness with rehabilitation ultrasound imaging (RUSI) before and after surgery. A retrospective cohort of 37,057 female frontline healthcare workers, a population at high risk of occupational LBI due to the heavy nature of their work, was extracted. Exclusion of 27,987 due to a history of back pain or injury, prior hysterectomy or failure to meet the provincial residency requirement of five years left a sample size of 9,070. Within this research sample, 634 (7%) had undergone hysterectomy, a prevalence much lower than the published value of 30%. Statistical analysis revealed no increased risk of LBI in this cohort of healthcare workers without prior history of LBI. Clinical RUSI assessment of the core muscles would investigate if this was because there was no change in the muscle function post-surgically. Validity and reliability of RUSI to evaluate core muscle function have been established for intersessions up to two weeks. A group of women not undergoing AH was used to establish reliability over intervals of four, eight and twelve weeks. Intraclass correlations (ICC₃,₁) ranging from 0.75 to 0.90 for measured muscle thickness in the deep abdominal and lumbar muscles exceeded the minimum standard of 0.70 for research purposes. Percent change measures did not meet this standard. A prospective descriptive case series involving nine individuals undergoing AH found post-surgical decreases in measurements of the deep abdominal stabilizers most notably in the participants with a history of previous low back pain/injury or who were obese. These findings support continued investigation of the relationship between AH and LBI including individuals with risk factors such as prior low back pain/injury and/or obesity.