Background & Aims
Visceral pain originates from the internal organs and is particularly difficult to treat1. In experimental studies, visceral pain is perceived as more unpleasant and intense than somatic pain2. Given the specific peripheral, physiological and central nervous underpinning mechanisms along the gut-brain axis, visceral sensation differs from sensations emanating from somatically innervated organs such as the skin or muscles1. Therefore, findings from somatic pain research cannot be easily transferred to visceral pain. However, visceral pain, especially after surgery, has been insufficiently studied and is not routinely assessed3. These gaps are especially problematic given the increasing frequency of abdominal surgery worldwide, such as caesarean section, especially without medical indication4. In order to expand knowledge about visceral pain after surgery, we recorded modality-specific pain and side effects in patients after caesarean section.
Methods
In an ongoing prospective observational study at the Department of Gynecology and Obstetrics at the University Hospital Essen, pregnant women (n=79; age: 33.16 years) were included before planned caesarean section. Preoperatively, pain expectations were evaluated. On the first postoperative day (D1), postoperative pain and side effects were recorded using a modified version of the PAIN-OUT questionnaire. In addition, based on pain localization, visceral pain, defined as pain deep in the abdomen, and somatic pain, defined as incisional pain in the area of the wound/scar, were assessed on visual analogue scales (VAS, “0” no pain at all to “100” worst pain imaginable; 0-100 mm). Statistical paired t-tests and repeated measures ANOVA were used.
Results
After caesarean section, minimal and maximal pain under the effect of pain medication were 3.3±2.5 and 7.6±1.9 (NRS±SD; 0-10), respectively. Pain was partly associated with abdominal bloating (57.8%), a sensation of fullness (24.1%) or occurred during urination (24.1%). Visceral pain was perceived as more severe compared to somatic pain (61.3±22.5 and 51.8±24.6; VAS±SD; p>0.001; Fig.1) and correlated with the strongest perceived pain (r=0.620; p>0.001). Preoperative expected pain intensity corresponded with perceived somatic pain, but not with visceral pain (ANOVA; p=0.002). Also, higher visceral pain intensity, but not somatic pain was correlated with more intense side effects such as drowsiness, nausea and dizziness.
Conclusions
Taken together, patients undergoing caesarean section experience severe pain and associated abdominal discomfort, confirming previous data. Even after surgery, visceral pain as more intense than somatic pain and particularly relevant for patients. Visceral pain was percieved as more intense than expected and was related to various side effects along the gut-brain axis. Therefore, the visceral component of pain after caesarean section appears to be particularly pronounced and has hardly been considered after surgery on visceral structures. The previous interdisciplinary approaches and knowledge of visceral pain along the gut-brain axis offer the potential to greatly expand our understanding of pain after surgery on visceral structures. To further deepen this insight and enable targeted interventions, visceral postoperative pain should be routinely recorded and further investigated.
References
1. Elsenbruch S, Benson S. Visceral Pain: From Bench to Bedside. In: The Senses: A Comprehensive Reference. Vol 5. Elsevier; 2020:592-603. doi:10.1016/B978-0-12-805408-6.00019-1
2. Koenen LR, Icenhour A, Forkmann K, et al. Greater fear of visceral pain contributes to differences between visceral and somatic pain in healthy women. Pain. 2017;158(8):1599-1608. doi:10.1097/j.pain.0000000000000924
3. Lavand’homme P. Chronic pain after childbirth. Curr Opin Anaesthesiol. 2013;26(3):273-277. doi:10.1097/ACO.0B013E328360C57B
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5. Aulenkamp JL, Malewicz NM, Brauckhoff JD, et al. Chronic Pain Following Fracture-Related Surgery: Posttraumatic Rather Than Postsurgical Origin Promotes Chronification-A Prospective Observational Study With 1-Year Follow-up. Anesth Analg. 2022;134(5):974-986. doi:10.1213/ANE.0000000000005807
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7. Gerbershagen HJ, Aduckathil S, van Wijck AJM, Peelen LM, Kalkman CJ, Meissner W. Pain Intensity on the First Day after SurgeryA Prospective Cohort Study Comparing 179 Surgical Procedures. Anesthesiology. 2013;118(4):934-944. doi:10.1097/ALN.0B013E31828866B3
Presenting Author
Jana Aulenkamp
Poster Authors
Jana Luisa Aulenkamp, M.D.
Dr. med.
Clinic for Anesthesiology and Intensive Care, University Hospital Essen, Germany
Lead Author
Franziska Welz
Lead Author
Antonella Iannaccone
Dr.
Lead Author
Esther Pogatzki-Zahn
University Clinic Muenster, Germany
Lead Author
Sigrid Elsenbruch
Prof. Dr.
Lead Author
Topics
- Specific Pain Conditions/Pain in Specific Populations: Acute Pain and Nociceptive Pain