Important considerations with respect to reducing the transition from acute to persistent postoperative pain

1. Introduction

Effective management of acute post surgical pain is one of the cornerstones of successful perioperative care. The principal objectives of post surgical pain management include relief of patient suffering, facilitation of functional recovery and attenuation of the physiologic stress response to pain and associated complications. More recently, the health-care community identified the importance of attenuating the transition from acute postsurgical pain to persistent postsurgical pain (PPSP) and recognizing the role played by the medical profession in the opioid crisis [1]. In prior publications, the standard of postoperative care has been discussed in detail [2,3]. In present day, this includes the implementation of multimodal analgesia (including novel regional anesthesia techniques and long-acting local anesthetics), interdisciplinary care among physicians, nurses, and allied health staff, as well as managing unique patient, surgical and pharmacotherapy interactions. In particular, it has long since been recognized that adequately treating acute pain is integral to minimizing the transition to persistent or chronic pain.

Over the past 5 years, a few key concepts in the management of acute postoperative pain have moved to the forefront. This includes patient-centered and procedure-specific education, nonpharmacological pain management strategies, utilization of a functional-based recovery assessment, ensuring an adequate transition from hospital to home pain management and exploring the role of a transitional pain service (TPS).

2. Preoperative and in-hospital care

2.1. Patient education and psychological support

Effective post surgical pain management starts preoperatively with tailored patient education. Egbert et al. was one of the first to demonstrate this in 1964 [4], and more recent studies have shown that tailored preoperative patient education can reduce postoperative opioid consumption, preoperative anxiety, requests for sedation, hospital length of stay [2] and postoperative pain scores [5]. Furthermore, there is evidence to support that patients who are not fully informed about postoperative pain may develop a mismatch between their pain expectations and actual pain experience, which can impact their postoperative recovery [6].

Despite the apparent benefit of preoperative patient education, there are still barriers to be overcome. Of the 1005 patients undergoing elective surgery surveyed during a 6-week period at the Brigham hospital in 2016, 80% denied receiving preoperative education on the risk of PPSP, even in high-risk surgeries including thoracotomy, mastectomy and total knee replacement [7]. A significant proportion of those same patients anticipated a less than 10% chance of PPSP, even in surgeries with a reported risk of up to 50%. This is consistent with our own experience at Toronto General Hospital (TGH). Given the morbidity associated with PPSP, thorough procedure-specific pain education is an essential component of informed consent (see Box 1). Additionally, this education may translate to a reduction in perioperative anxiety and improved coping in the postoperative period.

Box 1. Patient education – reproduced from [8] with permission of Taylor & Francis.

Expectations regarding functional recovery (return to meaningful physical activities) Realistic pain management goals (improved function vs. ‘zero pain’) Multimodal pain management options (opioid, nonopioid, and nonpharmacological) Possible interaction of the patient’s current medications and opioids (e.g. sleeping pills, alcohol, benzodiazepines) Risk of opioid side effects, overdose, and development of dependence or addiction Safe opioid use and discontinuation Risk factors for opioid use disorder (history of substance use disorder, depression, anxiety) Risk of persistent postsurgical pain – ranging from 5% to 10% after major surgery to nearly 50%-70% in thoracic or amputation surgery

Standard patient education may not be sufficient for all patients. A proportion of patients will be more successful if they are simultaneously taught psychological coping skills aimed at improving distress tolerance and decreasing pain catastrophizing [8]. Potentially employed techniques may include box breathing and behavioral activation. There is increasing evidence for the role of psychological intervention in perioperative pain management [3] and reducing the risk of PPSP [6] with more studies still to come.

2.2. Functional-based recovery assessment

Acute postoperative pain is most commonly assessed in clinical practice with the use of a numeric rating scales (NRS) or Visual Analog scales (VAS). In the case of the NRS, a patient is asked how severe their pain is on a scale of zero to 10, with 0 being no pain and 10 being ‘the worst imaginable’. This is often obtained at rest and with activity or deep breathing as a dynamic measure of pain severity. These scales are reproducible and validated; however, there is a risk of iatrogenic harm when opioids are prescribed with a sole focus on unidimensional scales [9]. Given this challenge, there is an emerging role for the use of functional-based assessment scales in the evaluation of acute pain. One such scale has the patient perform a task suitable to their level of recovery and scores them based on their ability to do it without pain, complete it with significant pain or not complete the task at all despite the pain severity [10]. The use of these scales may also help patients reframe their analgesic goals to facilitate functional recovery, rather than achieve a score of 0/10 on the NRS scale.

In 2017, the United States Joint Commission on Accreditation of Healthcare Organizations (JCAHO), implemented management standards advocating for functional-based pain assessment; however, independent validation of functional-based assessment scales is currently lacking. Preliminary data from a 2019 pilot study has shown that in a small sample size of patients, the Functional Assessment scale (FAS) correlated with NRS in cognitively intact patients [11].

3. Transitional care post hospital discharge

3.1. Acute post discharge period

Implementation of the above strategies can help improve in-hospital care and reduce iatrogenic harm from opioid overuse; however, additional issues arise at hospital discharge when patients must transition to managing their pain in the home environment. This has been a longstanding gap in patient care. There are many potential pitfalls in the post-discharge course, including: inconsistent patient education, opioid over-prescription, and limited support for patients at risk of developing PPSP and/or persistent opioid use.

Education that was delivered to patients in hospital should be re-iterated in both written and verbal form before discharge. Patients should be made aware that scheduled acetaminophen and NSAIDs are first line for the management of post surgical pain, with opioids only being added if there is a need for further analgesia. Standard opioid prescribing should be tailored to the expected functional recovery of each surgical intervention with part-fills used to avoid excessive left-over opioid medications [8]. Nonpharmacological coping strategies should be reinforced and information regarding the appropriate use, storage and disposal of remaining opioid medications (i.e. return to the pharmacy) should be provided [8]. A meta-analysis of 44 studies (13,068 patients) published in 2020 showed that 61% of opioids are left unused after surgery [12]. These excess opioids are at risk of being hoarded or diverted, and thus the prescribing practices at individual institutions should be adapted to reflect this data. A 2018 study showed that an educational intervention for health-care members can help reduce excessive postoperative opioid prescribing, without increasing the frequency of refill requests [13].

There is a significant risk that patients who are prescribed opioids after surgery will continue using them in the long term [14]. Risk factors include preoperative opioid use, preoperative pain, lower socioeconomic status, depression and antidepressant use, history of drug, alcohol or tobacco abuse and medical comorbidities [1,14]. Interestingly, PPSP has not been shown to be the primary determinant of persistent postoperative opioid use [15,16]. Given the harms demonstrated with long-term opioid use for chronic non-cancer pain, strategies for opioid cessation should be implemented concurrently with those that optimize postoperative pain. Discharge opioid prescriptions should be individualized for each patient and based on the last 24 hours of opioid consumption. Prediction models can be used to help anticipate the duration and total requirements of the opioid medication [8]. If a patient did not require opioid analgesia in the last 24 hours of admission, then an opioid should not be prescribed at discharge. Patients should be screened perioperatively for both risk factors of PPSP and persistent opioid use after surgery. A comprehensive plan should be implemented for these patients, including opioid-sparing techniques and a postoperative follow-up schedule and weaning plan [8].

Education in the preoperative period may also be more likely to succeed. The perioperative period has been identified as a ‘teachable moment’ for patients particularly with regards to smoking cessation [17]. Teachable moments allow for the opportunity to encourage healthy behaviors in our patients and perhaps similar success may be seen with regards to patient education on opioid weaning.

3.2. Post discharge care and transitional pain services

Given the significant time investment required for these patients and the limited resources of the primary care setting, the role of a dedicated Transitional Pain Service emerges to optimize patient care perioperatively. It has become apparent that the surgical capacity and expertise to manage patients that develop the associated complications of persistent postsurgical pain and persistent opioid use is overwhelmed. These minority of patients require a specialized service with interdisciplinary experience to provide wholistic care.

The TPS at TGH is an example of an interdisciplinary team of pain specialists, nurse practitioners, psychologists, physiotherapists and patient care coordinators. The goal of the program is to modify the pain trajectories of patients at increased risk of developing PPSP and to reduce opioid consumption in the long term while maintaining patient function [18]. Within the TPS, high-risk patients are identified preoperatively and followed postoperatively for a period of approximately 6 months. Referral criteria include a history of chronic pain, patients on greater than 90 MEQ morphine per day, poorly controlled acute pain or patients with anxiety, depression or high pain catastrophizing scores which may signal difficulty coping with pain in the postoperative period [18]. A patient commitment to opioid weaning with the use of non-opioid pain medications and nonpharmacological strategies is necessary [19]. The service at TGH also has an integrated technological pain monitoring program (e.g. Manage My Pain app) which now serves as a database and has demonstrated the ability to enhance patient care and self-management [20]. The TPS fills a specific care gap and provides close follow-up (as early as 1–2 weeks from initial in-hospital consult) for patients that otherwise may not be seen by their surgical team for 6–8 weeks postoperatively. An analysis of 251 patients enrolled in the TPS from 2014 to 2017, demonstrated that 45% of opioid-naïve and 26% opioid-experienced patients completely weaned from their opioids and 80% and 61% respectively weaned to less than half their baseline dose by 6 months following hospital discharge. Functional impairment from pain reported by pain interference scores improved by 21% from hospital discharge to the final TPS visit for the total study sample of patients [19]. An RCT comparing patients enrolled in a TPS program vs. the standard of care at five hospitals in Ontario is currently underway [21].

Hospitals attempting to implement a Transitional Pain service may encounter a few barriers in the process. There will be an initial period of staff education required to ensure engagement in the service and appropriate referrals. Similarly, time and dedication to building the allied health team of pain-oriented physiotherapists, psychologists and nurse practitioners is required and ensuring a collaborative working environment is key. Lastly, ensuring a supported discharge from the service can be a challenge. A subset of patients lack a primary care provider familiar with opioid weaning strategies, postoperative pain management and recovery. Furthermore, a significant proportion of patients do not have a primary care provider at all. Discharge planning from the Transitional Pain Service should be considered from the time of consultation. This will focus the patient and medical team toward a common goal of functional recovery in that timeframe. Continual communication with the primary care provider by way of dictated plans, or otherwise, is also required to ensure a seamless transition out of the clinic. On a broader scale, the continual education of primary care providers and trainees by pain specialists through academic and community centers will improve perioperative care overall. A knowledge translation tool is also being created to help others understand the critical building blocks associated with the creation of a TPS service.

4. Expert opinion

The landscape of acute postoperative pain management is evolving and new strategies are being implemented to ensure that individualized patient-centered care is kept at the forefront. Of note, recent literature shows that patients are unaware of the risk of the development of PPSP and that this, among other factors, increases their risk for persistent postoperative opioid use and the associated harms. More research is required in the field of nonpharmacological pain management options, to help reduce our healthcare system’s reliance on opioid centered treatment strategies. At our institution, studies examining clinical hypnosis and yoga are underway to determine their effectiveness on postoperative pain and opioid consumption. Additionally, a randomized controlled trial assessing the implementation of a preoperative patient education intervention on the effectiveness of postoperative pain management in the outpatient setting and is slated to be completed in 2021 [22].

One potential avenue for advancing the field of perioperative pain management is thorough the implementation of technology-based platforms. The COVID-19 pandemic has forced the swift adoption of virtual resources, and this has become even more essential to prevent gaps in patient care. A curated technologically based care plan can assist with patient self management through platforms like MMP [19] and facilitate virtual psychology and physiotherapy classes which can also ensure that patients in rural centers can receive timely and consistent care. Obvious pitfalls to the virtual care approach include the limited ability to perform a physical examination and the potential for breach of personal health information. The quality of patient care before and after the implementation of virtual care will be an area of study in the years ahead.

In the current perioperative environment: 1) patient education 2) appropriate pre- and perioperative assessment of patients at risk for developing persistent postoperative pain 3) optimal postoperative prescribing practices and 4) timely comprehensive follow-up by Transitional Pain Teams is paramount to improving patients’ acute pain and will hopefully reduce in the number of patients that go on to develop persistent postsurgical pain and opioid use.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This manuscript has not been funded.