Acute postoperative pain in 23 procedures of gynaecological surgery analysed in a prospective open registry study on risk factors and consequences for the patient

Abstract

Effective perioperative pain management is essential for optimal patient recovery after surgery and reduces the risk of chronification. However, in clinical practice, perioperative analgesic treatment still needs to be improved and data availability for evidence-based procedure specific analgesic recommendations is insufficient. We aimed to identify procedures related with high pain scores, to evaluate the effect of higher pain intensity on patients and to define patient and intervention related risk factors for increased pain after standard gynaecological and obstetrical surgery. Therefore, we performed a prospective cross-sectional study based on the German registry for quality in postoperative pain (QUIPS). A cohort of 2508 patients receiving surgery between January 2011 and February 2016 in our tertiary referral centre (university departments of gynaecology and obstetrics, respectively) answered a validated pain questionnaire on the first postoperative day. Maximal pain intensity was measured by means of a 11-point numeric rating scale (NRS) and related to procedure, perioperative care as well as patient characteristics. The interventions with the highest reported pain scores were laparoscopic removal of ovarian cysts (NRS of 6.41 ± 2.12) and caesarean section (NRS of 6.98 ± 2.08). Factors associated with higher pain intensity were younger age (OR 1.75, 95% CI 1.65-1.99), chronic pain (OR 2.08, 95% CI 1.65-2.64) and surgery performed outside the regular day shift (OR 1.67, 95% CI 1.09-2.36). Shorter duration of surgery, peridural or local analgesic and preoperative sedation reduced postoperative pain. Patients reporting high pain scores (NRS ≥ 5) showed relevant impairment of daily activities and reduced satisfaction. Caesarean section and minimal invasive procedures were associated with the highest pain scores in the present ranking. Pain management of these procedures has to be reconsidered. Younger age, receiving surgery outside of the regular shifts, chronic pain and the surgical approach itself have a relevant influence on postoperative pain intensity. When reporting pain scores of 5 or more, patients were more likely to have perioperative complications like nausea or vomiting and to be impaired in mobilisation. Registry-based data are useful to identify patients, procedures and critical situations in daily clinical routine, which increase the risk for elevated post-intervention pain. Furthermore, it provides a database for evaluation of new pain management strategies.

Figure 1

Patient inclusion process.

Figure 2

Ranking of postoperative pain depending on type of surgery. Postoperative pain scores 24-32 h after surgical procedures. Horizontal box plots indicate worst pain since surgery on 11-point numeric rating scale (NRS). Box edges indicate 25th and 75th percentiles. Whiskers indicate 5th and 95th percentiles. Procedures ranked in descending order of median pain severity. Mean scores (also shown) were used to rank surgical groups with identical median NRS scores. NRS scores were adjusted for age, surgical approach, use of innovative pain strategies, chronic pain patient and time of beginning of surgery using the regression equation.

Figure 3

Association between risk factors and risk of increased pain. Binary logistic regression analysis adjusted by age, chronic pain, surgical approach, time point of surgery, use of wound infiltration, prophylactic oxycodone, opioids and epidural catheter. Reference variables: (a) age > 71 years; (b) breast surgery; (c) standard care.

Figure 4

Comparison of side effects and impairment depending on pain score. Percentage of patients reporting side effects. Patients with high pain scores on 11-point numeric rating scale (NRS ≥ 5) on first postoperative day compared with patients showing low pain intensity (NRS < 5). Chi-Square-Test indicates a statistically significant difference for each comparison. (p < 0.05).