In conjunction with the 2017 Global Year Against Pain After Surgery, IASP’s Acute Pain SIG collaborated with the European Pain Federation (EFIC) to organize and bring to fruition a number of activities and publications. These activities have ranged from Fact Sheets, to publication of the proceedings of a symposium in PAIN Reports, to the upcoming book Pain After Surgery (an updated IASP Press monograph on this topic), to formal endorsement of the Global Year effort by numerous professional organizations.
The latest effort affirming this theme took place in September at EFIC’s 10th Congress, during which a full day was devoted to a preconference satellite organized by IASP AP SIG Chair Stephan Schug and Vice Chair Esther Pogatzki-Zahn. The carefully selected expert presenters were grouped into four topics:
- Acute Pain after Surgery: Lessons Learned from the Last Decade (chairs: Esther Pogatzki-Zahn and Daniel B. Carr)
- Acute Pain Management: Change the Vision (chairs: Winfried Meissner and Stephan Schug)
- Transition from Acute to Chronic Pain After Surgery (Chairs: Jane Quinlan, Esther Pogatski-Zahn)
- Treatment of Chronic Pain After Surgery: New Approaches (Chairs: Stephan Schug, Dominique Fletcher)
The individual talks, along with a brief precis of each talk provided by its presenter, follow at the end of this article.
Many aspects of the broader EFIC Congress addressed pain after surgery or related topics. AP SIG officers as well as world-renowned leaders in the field of postoperative pain control, such as Henrik Kehlet from Denmark, presented plenary or refresher course lectures.
Another EFIC preconference on preventing chronic postsurgical pain discussed new clinical trial results for a novel therapeutic, an oligonucleide inhibitor targeting the upregulation of the transcription factor EGR1. As described by Donald Manning, who chaired the workshop, EGR1 induction is known to regulate a variety of inflammatory and pain-inducing pathways whose activation after trauma contribute to sensitization and chronification.
Dan Carr, Oscar de Leon-Casasola, Henrik Kehlet, and Stephan Schug, along with Julien Mamet discussed findings of persistent decreases in pain at rest and during walking for at least six weeks following a single perioperative administration to patients undergoing knee replacement.
The conference center and organizers were excellent, and the weather cooperated by raining at times when it served the conference well to have people not off sightseeing. The conference banquet dinner took place at the Danish National Museum amid remarkable archaeological finds and cultural artifacts. The last evening of the EFIC Congress welcomed attendees to an unusual and memorable dinner experience in a spectacular venue featuring “Copenhagen street food” and other international fare. Luckily, this venue was mere steps away from the canals, which offered picturesque views as twilight proceeded into night.
--Text and photos (except as indicated) by Dan Carr, Immediate Past Chair, IASP Acute Pain SIG
Henrik Kehlet of Denmark, a leader in the field of postsurgical pain, delivered a plenary lecture.
EFIC delegates enjoyed an evening
of “Copenhagen street food” at a city market.
Babita Ghai of India, incoming AP SIG newsletter co-editor, and outgoing AP SIG Chair Dan Carr spoke at the satellite meeting.
Following are summaries of the presentations from each speaker in order of their presentations:
Acute Pain after Surgery: Lessons Learned from the Last Decade
Daniel Segelcke, “Lessons learned from animal studies”: Clinical pain management after surgery is far from being successful despite dramatically increased scientific evidence in this area. The under treatment of postoperative pain has many reasons; one of the more important is the limited translation of basic and clinical findings into clinical practice. Postoperative pain models characterize by showing resting pain, mechanical/heat hyperalgesia, movement-evoked pain, and anxiety/depression behavior and thus simulate pain after surgery in patients. Postoperative pain represents a unique pain entity in spinal and supraspinal structures and molecular pathways.
Dominic Aldington, “Lessons learned from Cochrane Reviews”: The Cochrane database is a valuable resource for clinicians, but it does not, on its own, constitute evidence-based medicine; this is instead a fusion of clinical experience with “external” evidence. We must consider the wider aspects of the health-care service and the system we use; we must not expect a “magic bullet” to do everything for our patients and us.
Stephan Schug, “Lessons learned from analysis of scientific evidence”: From scientific evidence, we have learned primarily that pain relief after surgery should be multimodal and procedure-specific. Multimodal analgesia ideally should have an opioid-sparing effect, thereby reduce adverse effects of opioids while improving pain control. This approach is governed by use of regional analgesia whenever possible and a concept of maximizing non-opioids and minimizing opioids. In parallel, as analgesic medications and techniques have different effects in different surgical settings, provision of postoperative analgesia should be procedure-specific.
Winfried Meissner, “Lessons Learned from Big Data”: Big data is often defined as data too big, too complex, too weakly structured, or too speedy to process with conventional computing resources. In clinical acute pain research, large registries or routine data (e.g., EMR) do not always fulfill “Big Data” definitions but challenge researchers by complexity. In contrast to RCTs, registries, and routine data often include patients with rare conditions, may detect infrequent complications, mirror “real life,” and create new hypotheses. Known and unknown confounders may bias findings of registry data; therefore, associations are not necessarily of causal relationship.
Acute Pain Management: Change the Vision
Ulrike Stamer, “Too much pain after C-Section?”: Data from scientific studies/RCTs provide evidence that good pain control after Cesarean section is possible; however, these settings do not reflect everyday clinical practice. The UK Royal College of Anaesthetists suggested several quality indicators aimed at pain management after Cesarean section, which are not met, if analyzing data of the international acute pain registry PAIN OUT. Pain scores are too high, time in severe pain too long, and non-opioid analgesics not used on a regular basis in daily clinical routine. There is a need for meaningful but realistic quality criteria reflecting pain-related short-term and long-term outcomes and functional impairment after Cesarean section.
Madelon Peters,“Psychological Aspects: How important are they and how can we target them perioperatively?”: There is now a large evidence base showing that psychological distress factors are associated with elevated levels of acute postsurgical pain and a higher incidence of persistent postsurgical pain. The most prominent factors appear to be pain catastrophizing and anxiety, explaining around 10-15% of variance in acute pain intensity. Perioperative psychological interventions targeting catastrophizing and anxiety with the aim to decrease postoperative pain appear to be promising, but the evidence for their efficacy is still limited. Interventions should be brief, and mode of delivery should be practical, so that they can be implemented in clinical practice.
Esther Pogatzki-Zahn, “Can we predict pain outcome after surgery?”: Although many therapeutic methods and drugs are available, pain after surgery is not sufficiently managed. One reason might be the different response to surgery and analgesics between individual patients. Some patients are more susceptible than others for developing severe pain and pain-related functional impairment. A preoperative identification of patients at high risk for “poor” pain outcome would help to decide which patients might be placed on more intense treatment options. By using data from acute pain registry projects, we were able to identify easy-to-assess risk factors; by using these factors in clinical practice, further studies are warranted to show an improvement by using these risk factors, for instance to identify the ideal pain-management strategies in these patients to reduce pain and pain-related impairment.
Babita Ghai, “Postoperative pain (POP) management in older persons”: Babita Ghai emphasized that with rapid growth of the aging population, more elderly will require surgery; hence, perioperative care. She discussed the magnitude and challenges faced for POP management in this special population. She presented the recent evidence for pain management with a focus on the concept of multimodal analgesia and “start slow and go slow” in this population.
Transition from Acute to Chronic Pain After Surgery
Patricia Lavand’homme, “Prolonged pain after surgery: hype or real problem?”: Prolonged pain after surgery is a socio-economic problem. From multiple retrospective and prospective studies, estimates are that one patient out of 10 will develop long-lasting pain after surgery, and one patient out of 100 will suffer severe prolonged pain affecting rehabilitation and quality of life, particularly when the pain involves a neuropathic component (35 to 57% of the cases). The incidence unfortunately has not changed over the last 20 years and is similar in ambulatory and pediatric patients. Reports from the recently developed “Transitional Pain Clinics” (also called “APS Out-Patient Clinic”) support observations from the literature. Even more, they highlight the humanistic and economic burden of the problem. These reports also underline the difficulty to relieve the neuropathic pain component, which is extremely frequent in severe prolonged postsurgical pain as well as the risk of dependence to prescribed postoperative painkillers (mostly opioids and gabapentinoids).
Dominique Fletcher, “Prediction of prolonged pain after surgery”: The risk of chronic postsurgical pain (CPSP) should be part of preoperative determinants of surgical indication, surgical technique, surgeon, and institution choice. Nerve lesion is an important factor but is not always responsible for CPSP. Partial nerve lesion should be avoided. The most significant patient-related predictive factors of CPSP are young age, preoperative pain, preoperative opioid use, and psychological factors. Early postoperative warnings of CPSP are intensity and neuropathic characteristics of postoperative pain and hyperalgesia. We should organize early detection (specific follow up; dedicated consultation) and try to define validated predictive scores for the pre or postoperative period.
David Yarnitsky, “Prevention of chronic postsurgical pain, how can we tailor the correct mechanisms?”: David Yarnitsky reviewed pronociception, as evaluated by conditioned pain modulation and temporal summation and its influence in postoperative pain. He elaborated on “fix the dysfunction” principle in tailoring pain therapy; drugs that augment pain inhibition, i.e. SNRIs, should best help patients with dysfunctional, reduced pain inhibition, while drugs that reduce pain facilitation, i.e. gabaoentinoids, should best help patients with dysfunctional, augmented pain facilitation.
Eske Aasvang, “The role of surgical factors”: Any surgical procedure will result in injury to nerves (cutaneous, deeper, visceral) resulting in acute pain resolving within weeks/months in the majority of cases but progressing to moderate/severe persistent pain in 5-15% of cases, depending on the procedure. Likewise, inflammation from the surgical injury is increased with the magnitude of trauma and together with the nerve injury may play a crucial role in the transition to chronic postsurgical pain. As such, future investigation on the transition from acute to chronic pain should focus on the interaction between the two nociceptive pathways and guide interventional studies. Furthermore, studies need to recognize the importance of details in the surgical procedure as differences in the size of trauma (laparoscopic versus open), nerve handling (transection versus preservation) implantation (mesh versus no mesh), tourniquet use, etc., all may be relevant factors for acute and persistent pain.
Treatment of Chronic Pain After Surgery: New Approaches
Hanse Clark, “Do we need a new organizational approach for the treatment of persistent postsurgical pain in outpatient clinics?” With the current concern about opioid prescribing, the postsurgical period remains a critical window with the risk of significant opioid dose escalation, particularly in patients with a history of chronic pain and presurgical opioid use. Dr. Clarke discussed the development and implementation of a Transitional Pain Program at the Toronto General Hospital that enables close monitoring of pain, opioid medications, and mental health vulnerabilities that place certain patients at a higher risk of developing chronic postsurgical pain. The economic cost to society for the development of chronic postsurgical pain was discussed in detail. Beyond in-hospital interventions, he is working to scale the Transitional Pain Program post-discharge, involving community partners, to tackle the current public health crisis of pain and opioid addiction.
Audun Stubhaug, “Pharmacological management of chronic pain after surgery: Is it special?”: A large proportion of chronic postsurgical pain can be classified as neuropathic, with differences between different surgical procedures. A careful examination of pain history and patient may identify different pain components with different mechanisms. Peripherally driven pain can be treated with peripheral approaches such as topicals and peripherally acting drugs. Identified neuropathic, nociceptive, and inflammatory pain components should be treated according to general guidelines for chronic pain.
Ralf Baron, “QST—predictor of treatment outcome?”: Patients with peripheral neuropathic pain are heterogeneous in etiology, pathophysiology, and clinical appearance. We examined more than 1,100 patients with quantitative sensory testing and classified the patients into three subtypes with distinct sensory profiles. These profiles reflect neurobiological mechanisms and are independent of the underlying etiology. Recent clinical trials with oxcarbazapine or botulinum toxin using a phenotype-stratified approach demonstrated that subgroups of patients respond better than others. Consequently, cohorts in clinical trials should be stratified and potentially enriched with patients who likely respond to the study drug based on the sensory profile rather than on the underlying etiology. This approach has the potential to minimize pathophysiological heterogeneity within the groups under study and to increase the power to detect a positive treatment result. In clinical proof-of-concept trials, the study population can be enriched prospectively on the basis of “a priori” defined entry criteria.