Chronic post-surgical pain is a common perioperative complication and may be seen in up to 85% of patients undergoing certain types of surgery, for example limb amputation. In the obstetric population, pain is often present after delivery, with a higher incidence after caesarean section than vaginal delivery. Chronic pain may develop; this is usually diagnosed at 2-3 months, when acute pain associated with tissue damage is expected to have passed. Depending on the definition given in terms of duration and source of pain, chronic pain has been reported in 5-25% of women after caesarean section.
Problems and special considerations
The pathogenesis of chronic post-surgical pain is thought to be related to tissue damage and nerve injury, with release of inflammatory mediators (e.g. cytokines, bradykinin and prostaglandins), loss of inhibitory neurones, amplification of sensory input, and spontaneous ectopic discharges causing hypersensitivity and allodynia. Central sensitisation is an important trigger for the development of persistent pain, so anaesthetic and analgesic techniques aimed at attenuating sensitisation may be of benefit.
Certain groups may be at an increased risk for the development of chronic pain after caesarean section; these include women with increased anxiety about childbirth and those with pre-existing chronic pain syndromes. There may also be a genetic predisposition for the development of chronic pain syndromes. Studies report that women who experience severe acute postpartum pain have a 2.5-fold increased risk of experiencing a chronic pain syndrome.
Some studies have shown that women who have a caesarean section under general anaesthetic seem to be at increased risk of chronic pain. This may be related to increased nociceptive afferent transmission perioperatively and worse control of pain in the immediate postoperative period.
Persistent postpartum pain may have far-reaching consequences. It has been associated with a decreased quality of life, impaired activities of daily living and an increased incidence of postnatal depression.
Management options
By identifying those at risk, such as those with pre-existing chronic pain or particular anxieties about childbirth, an antenatal plan can be made in an attempt to reduce the risk; efficacious analgesia such as effective epidural analgesia during delivery can be recommended, and effective post-delivery analgesia provided.
Multimodal analgesia should be offered to all women, particularly those who have a caesarean delivery. This should include simple analgesics, opioids (preferably neuraxial) and local anaesthetic techniques; this is particularly relevant to those who deliver under general anaesthesia. If an epidural is in situ, long-acting opioids should be given at the end of the procedure unless contraindicated. If an epidural is not in situ, local anaesthetic techniques such as transversus abdominis plane (TAP) blocks should be employed. Use of preoperative gabapentin has been shown to reduce acute pain scores at the expense of increased sedation in the obstetric population; there is no evidence of a reduction in chronic pain, but study numbers have been small. There is some suggestion that intrathecal clonidine may decrease the risk of developing chronic pain by reducing hyperalgesia; however, its use is not common and it is not licensed for use in obstetric practice.
Any acute postpartum pain should be addressed proactively. Issues may be actively sought during routine follow-up.
If chronic post-caesarean pain does develop, it should be treated in the conventional way of managing chronic pain. After underlying causes have been ruled out, appropriate multimodal analgesia should be prescribed, depending on the nature of the pain (e.g. neuropathic versus somatic). Patient education, counselling and anti-neuropathic agents such as amitriptyline or gabapentin may be beneficial. If the severity of pain and impact on life are severe, referral to pain specialists may be required. However, most studies in the obstetric population indicate that chronic pain is often not severe and tends to improve spontaneously with time.
Key points
• Chronic pain after a caesarean section is a common complication.
• Acute postoperative pain is a recognised risk and should be managed promptly.
Further reading
Daly B, Young S, Marla R, et al. Persistent pain after caesarean section and its association with maternal anxiety and socioeconomic background. Int J Obstet Anesth 2017; 29: 57-63.
Jin J, Peng L, Chen Q, et al. Prevalence and risk factors for chronic pain following cesarean section: a prospective study. BMC Anesthesiol 2016; 16: 99.
Weibel S, Neubert K, Jelting Y, et al. Incidence and severity of chronic pain after caesarean section: a systematic review with meta-analysis. Eur J Anaesthesiol 2016; 33: 853-65.