Chronic Postsurgical Pain: Early Recognition and Referral

Dr Tay Yoong Chuan
Service Chief @ KKH Women’s, SingHealth Duke-NUS Pain Centre;
Senior Consultant, Department of Pain Medicine,
Director, Ambulatory Surgery Centre, Singapore General Hospital;
Director, Women’s Pain Management Centre, KK Women’s and Children’s Hospital

Chronic postsurgical pain is often under-recognised due to the lack of physical symptoms and misconceptions of the recovery process. Given its multifactorial nature that spans multiple medical specialties, optimal management is best achieved through a specialised pain management centre that offers coordinated multidisciplinary care.

The SingHealth Duke-NUS Pain Medicine Centre shares this article so that GPs can be aware of this condition and consider early referral to ensure timely and effective management.

CASE VIGNETTE
Madam F, a 32-year-old woman, presented with chronic abdominal pain after a laparoscopic abdominal surgery overseas seven years ago. After diagnostic imaging, endoscopies and laparoscopy with multiple specialties revealed no surgical pathology, she was started on an anticonvulsant and analgesia. Her pain persisted even after her delivery via Caesarean section. However, with medications she is able to maintain an independent life raising a family.

INTRODUCTION

Patients may present with persistent pain even after significant time for healing has elapsed following their surgical procedures, which poses a significant burden on their function, psychological and psychosocial quality of life.

Instinctively, investigations and reviews would be performed to rule out red flags that require timely diagnosis and treatment. However, when these investigations return unremarkable, the patient may remain puzzled as to the diagnosis of their pain.

INCIDENCES

Chronic postsurgical or post-traumatic pain (CPSP) may be under-recognised, under-reported, and consequently, undertreated.

Published studies suggest an incidence, depending on the type of operation from 5% to 85%.¹

This wide variability in incidence has been attributable to methodological differences by different data collection methods and variable definitions of CPSP.

Increased volume of surgeries with high risk of CPSP such as hip and knee arthroplasties result from obesity, inflammatory disease and increased life expectancy.²

Severe CPSP negatively affects quality of life in 2-15% of patients.³

DEFINITION OF CPSP

In 2019, a taskforce of the International Association for the Study of Pain (IASP) provided a distinct definition of CPSP and devised a corresponding coding system to be updated into the 10th version of the International Classification of Diseases (ICD-10) coding system of the World Health Organization.

This crucial CPSP inclusion into the ICD-11 is an advancement in defining and acknowledging CPSP as a secondary pain condition instead of merely a symptom, highlighting the need for disease-specific management and for future studies to accurately report its incidence.²

Incidences of CPSP for different types of surgery

• Data adapted from several studies.^1,3,5,6,12 
• Severe CPSP is defined as pain ratings of ≥5 on scale from 0 (no pain) to 10 (worst possible pain).^3,11 
• CPSP: chronic postsurgical pain; NP: neuropathic pain

CPSP has been defined as pain that:

• Develops or increases in intensity after a surgical procedure or tissue injury 
• Persists beyond the healing process of at least three months from the initiating event and 
• Is localised to the surgical field or area of injury or projected to the innervation territory of a nerve situated in the area, or referred to a dermatome

Other causes of pain such as preexisting pain conditions, infections or malignancy should be excluded.⁴
 

Table 2
Ref: Schug SA, Lavand’homme P, Barke A, et al. The IASP classification of chronic pain for ICD-11: chronic postsurgical or posttraumatic pain. Pain 2019; 160:45–52.

RISK FACTORS

Preventative treatment strategies would be possible if at-risk patients can be identified early, pre-, intra and post-operatively.

A summary of the risk factors in the chart compiled from different studies, has not produced conclusive evidence.

Surgical predictive risk factors include extent, duration of surgery and type of tissue (nerve) injured. The authors postulated that minimally invasive surgery does not always reduce the risk of CPSP if relevant tissue was injured.² Adjuvant treatment (chemo-/radiotherapy) and reoperation may also contribute to CPSP.

Some studies have suggested that acute postoperative pain intensity, duration, pain trajectories and neuropathic-like features are strongly associated with CPSP.

Patient predisposing factors include:

• Young (adult) age 
• Female gender 
• High BMI 
• Preoperative chronic pain at surgical site 
• Pre-existing chronic painful conditions (e.g., fibromyalgia, myalgia, low back pain) and 
• Long-term opioid use²

Guisti et al. highlighted anxiety to be the main psychological risk factor for CPSP compared to depression, catastrophising, kinesiophobia and impaired self-efficacy.⁵

Current predictive risk tools are not applicable to the clinical setting as they are limited by small sample size, limited surgical procedures and lack of validation in a separate cohort.²

PREVENTION

Perioperative regional anaesthesia has been shown to reduce the risk of CPSP in most types of surgeries.⁷

Although perioperative use of gabapentinoids does not reduce CPSP incidence⁸, gabapentinoids can reduce neuropathic pain, which may be appropriate in complex surgeries resulting in nerve damage. Intravenous lidocaine infusions have been studied to reduce CPSP in breast surgery patients, although recommendations of adequate dose and duration have not been recommended.

PERSISTENT PAIN AFTER CHILDBIRTH (PPAC)

While PPAC has a wide incidence of 0.3-55% due to the lack of a consensus definition⁶, it affects maternal quality of life, with association with postpartum depressive symptoms.

Possible risk factors include severe postpartum pain, maternal genetics, psychosocial factors inclusive of depression, psychological vulnerability, stress, pain catastrophising, anxiety and social deprivation, recurrent Pfannenstiel incision and parietal peritoneum closure.⁶ Further research is required to develop at-risk patient identification models to allow early management.

CONCLUSION

Chronic pain patients with CPSP have complex individualised psychosocial processes which may evolve over time. A multimodal, multidisciplinary approach with combination of pharmacological and non-pharmacological management including physiotherapy and psychological support has provided positive results.

Early referral of patients to Pain Management Clinics could be considered when symptoms of pain persist longer than the expected time of healing and when escalating doses of analgesics including neuropathic pain medications prescribed have not alleviated their pain.

REFERENCES

1. Kehlet H, Jensen TS, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet 2006;367:1618-2.
2. DC Rosenberger, EM Pogatzki-Zahn, Chronic post-surgical pain-updated on incidence, risk factors and preventive treatment options BJA Educ. 2022 May; 22(5):190-196. doi:10.1016/j.bjae.2021.11.008
3. Fletcher D, Stamer UM, Pogatzki-Zahn E, Zaslansky R, Tanase NV, Perruchoud C, Kranke P, Komann M, Lehman T, euCPSP group for the Clinical Trial Network groupof the European Society of Anaesthesiology, Meissner W. Chronic postsurgical pain in Europe: an observational study. Eur J Anaesthesiol 2015;32:725–34.
4. Schug SA, Lavand’homme P, Barke A, et al. The IASP classification of chronic pain for ICD-11: chronic postsurgical or posttraumatic pain. Pain 2019; 160:45–52.
5. Giusti EM, Lacerenza M, Manzoni GM, Castelnuovo G. Psychological and psychosocial predictors of chronic postsurgical pain: a systematic review and metaanalysis.Pain 2021; 162: 10e30

Dr Tay Yoong Chuan completed his fellowship training in Pain Management at Addenbrooke’s Hospital, United Kingdom in 2016. Currently a Senior Consultant in Anaesthesiology and Pain Management in Singapore General Hospital, he has also been serving as the Director of Women’s Pain Management Centre at KK Women’s and Children’s Hospital since 2018. Dr Tay was also appointed as the Director, Ambulatory Surgery Centre, SGH from 1 October 2020.

In addition, Dr Tay holds teaching appointments such as Physician Faculty Member of the SingHealth Anaesthesiology Residency Programme, Assistant Professor with Duke-NUS School of Medicine and Clinical Lecturer with NUS-YLL School of Medicine.

GPs can call our Pain Management Clinics for appointments at the following hotlines for more information:

Singapore General Hospital
Pain Management Centre: 63214377

Changi General Hospital
Chronic Pain Clinic: 6788 3003

Sengkang General Hospital
Pain Management Clinic: 6930 6000

KK Women’s and Children’s Hospital
Women's Pain Centre: 6394 8073
Children's Pain Management Clinic: 6394 8459
Referrals: cpmc@kkh.com.sg