Early postoperative neuropathic pain assessed by the DN4 score predicts an increased risk of persistent postsurgical neuropathic pain

Efficacy and safety of perioperative ketamine for the prevention of chronic postsurgical pain: A meta-analysis

STUDY OBJECTIVE

Assessment of the efficacy and safety of perioperative intravenous ketamine in reducing incidence and severity of chronic postsurgical pain.

STUDY DESIGN

A systematic review and meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

The following data sources were systematically searched: MEDLINE, CENTRAL, and EMBASE (till 02/2021).

PATIENTS

Adult patients undergoing any surgery.

INTERVENTIONS

Perioperative use of intravenous ketamine as an additive analgesic drug compared to placebo, no active control treatment, and other additive drugs.

MEASUREMENTS

Primary outcomes were number of patients with chronic postsurgical pain after 6 months and ketamine related adverse effects. Secondary outcomes were chronic postsurgical pain incidence after 3 and 12 months, chronic postsurgical neuropathic pain incidence, chronic postsurgical moderate to severe pain incidence, intensity of chronic postsurgical pain at rest, and during movement, oral morphine consumption after 3, 6, and 12 months and incidence of opioid-related adverse effects.

MAIN RESULTS

Thirty-six RCTs were included with a total of 3572 patients. Ketamine compared to placebo may result in no difference in the number of patients with chronic postsurgical pain after 6 months (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.71-1.05; I2  = 34%; 16 studies; low-certainty evidence). Ketamine may reduce the incidence of chronic postsurgical neuropathic pain after 3 months in comparison to placebo (RR 0.78, 95% CI 0.62-0.99, I2  = 31%, seven trials, low-certainty evidence). Ketamine compared to placebo may increase the risk for postoperative nystagmus (RR 9.04, 95% CI 1.15-70.90, I2 30%, two trials, low-certainty evidence) and postoperative visual disturbances (RR 2.29, 95% CI 1.05-4.99, I2 10%, seven trials, low-certainty evidence).

CONCLUSIONS

There is low-certainty evidence that perioperative ketamine has no effect on chronic postsurgical pain in adult patients. Low-certainty evidence suggests that ketamine compared to placebo may reduce incidence of chronic postsurgical neuropathic pain after 3 months. Questions like ideal dosing, treatment duration and more patient-related outcome measures remain unanswered, which warrants further studies.

PROTOCOL REGISTRATION

Prospero CRD42021223625, 07.01.2021.

How to Modulate Peripheral and Central Nervous System to Treat Acute Postoperative Pain and Prevent Pain Persistence

Chronic postoperative pain (CPSP) is a major issue after surgery, which may impact on patient's quality of life. Traditionally, CPSP is believed to rely on maladaptive hyperalgesia and risk factors have been identified that predispose to CPSP, including acute postoperative pain. Despite new models of prediction are emerging, acute pain is still a modifiable factor that can be challenged with perioperative analgesic strategies. In this review we present the issue of CPSP, focusing on molecular mechanism underlying the development of acute and chronic hyperalgesia. Also, we focus on how perioperative strategies can impact directly or indirectly (by reducing postoperative pain intensity) on the development of CPSP.

Evaluation of Neuropathic Pain after Total Knee Arthroplasty: Do Yellow Flags Matter?

Up to 20% of total knee arthroplasty (TKA) patients continue to experience chronic postsurgical pain. Various factors have been identified as potential contributors, including so-called "yellow flags", encompassing symptoms of depression, anxiety, and catastrophizing, which were examined in this study to assess their predictive value concerning functional outcomes after TKA.

METHODS

Fifty TKA patients were categorized into high-risk and low-risk groups based on clinical assessment, demographic data, medication, and patient-reported outcome measures (DN4, SF-36, WOMAC, NRS, Fibromyalgia Survey Questionnaire, Pain Catastrophizing Scale, and Hospital Anxiety and Depression Scale). Postoperative outcomes within six months after TKA were then compared.

RESULTS

Both groups exhibited significant (p < 0.001) improvements in all WOMAC and NRS subscales, as well as in the physical function, role physical, pain, and energy/fatigue subdomains of the SF-36 after six months, while the high-risk group showed lower WOMAC scores regarding stiffness (19.0 ± 18.3 vs. 27.2 ± 20.7, p < 0.001) and pain (13.5 ± 13.3 vs. 15.1 ± 16.3, p = 0.029). The high-risk group showed significantly worse preoperative DN4 scores (1.8 ± 1.3 vs. 3.0 ± 1.1, p = 0.002) than the low-risk group, which persisted for one day (2.3 ± 1.2 vs. 3.5 ± 1.5, p = 0.005) and six weeks (2.2 ± 1.9 vs. 3.6 ± 2.3, p = 0.041) postoperatively.

CONCLUSIONS

Our results indicate that pre-existing yellow flags contribute to a more challenging early postoperative phase, underscoring the importance of considering individual patient characteristics and psychological factors to optimize TKA outcomes.

Mechanisms inherent in acute-to-chronic pain after surgery - risk, diagnostic, predictive, and prognostic factors

PURPOSE OF REVIEW

Pain is an expected consequence of a surgery, but it is far from being well controlled. One major complication of acute pain is its risk of persistency beyond healing. This so-called chronic post-surgical pain (CPSP) is defined as new or increased pain due to surgery that lasts for at least 3 months after surgery. CPSP is frequent, underlies a complex bio-psycho-social process and constitutes an important socioeconomic challenge with significant impact on patients' quality of life. Its importance has been recognized by its inclusion in the eleventh version of the ICD (International Classification of Diseases).

RECENT FINDINGS

Evidence for most pharmacological and non-pharmacological interventions preventing CPSP is inconsistent. Identification of associated patient-related factors, such as psychosocial aspects, comorbidities, surgical factors, pain trajectories, or biomarkers may allow stratification and selection of treatment options based on underlying individual mechanisms. Consequently, the identification of patients at risk and implementation of individually tailored, preventive, multimodal treatment to reduce the risk of transition from acute to chronic pain is facilitated.

SUMMARY

This review will give an update on current knowledge on mechanism-based risk, prognostic and predictive factors for CPSP in adults, and preventive and therapeutic approaches, and how to use them for patient stratification in the future.

Prognostic models for chronic postsurgical pain-Current developments, trends, and challenges

PURPOSE OF REVIEW

Prognostic models for chronic postsurgical pain (CPSP) aim to predict the likelihood for development and severity of CPSP in individual patients undergoing surgical procedures. Such models might provide valuable information for healthcare providers, allowing them to identify patients at higher risk and implement targeted interventions to prevent or manage CPSP effectively. This review discusses the latest developments of prognostic models for CPSP, their challenges, limitations, and future directions.

RECENT FINDINGS

Numerous studies have been conducted aiming to develop prognostic models for CPSP using various perioperative factors. These include patient-related factors like demographic variables, preexisting pain conditions, psychosocial aspects, procedure-specific characteristics, perioperative analgesic strategies, postoperative complications and, as indicated most recently, biomarkers. Model generation, however, varies and performance and accuracy differ between prognostic models for several reasons and validation of models is rather scarce.

SUMMARY

Precise methodology of prognostic model development needs advancements in the field of CPSP. Development of more accurate, validated and refined models in large-scale cohorts is needed to improve reliability and applicability in clinical practice and validation studies are necessary to further refine and improve the performance of prognostic models for CPSP.

Comparison between supra-inguinal fascia iliaca and pericapsular nerve group blocks on postoperative pain and functional recovery after total hip arthroplasty: A noninferiority randomised clinical trial

BACKGROUND

Pain after a posterolateral approach for total hip arthroplasty (THA) may affect early functional recovery. Supra-inguinal fascia iliaca (SFIB) and pericapsular nerve group (PENG) blocks have been proposed as promising analgesia techniques.

OBJECTIVES

This trial was conducted to compare a PENG with a SFIB for controlling postoperative pain and for providing functional recovery.

DESIGN

Noninferiority monocentric randomised controlled study.

SETTING

One hundred and two patients scheduled for a total hip arthroplasty via the posterolateral approach under spinal anaesthesia were prospectively allocated to two groups. Data acquisition occurred between October 2021 and July 2022 at the University Hospital of Liege.

PATIENTS

One hundred and two patients completed the trial.

INTERVENTIONS

Group SFIB received supra-inguinal fascia iliaca block (SFIB) (40 ml ropivacaine 0.375%), whereas group PENG received a PENG block (20 ml ropivacaine 0.75%).

MAIN OUTCOME MEASURES

Rest and mobilisation pain on a 0 to 10 numeric rating scale at fixed time points: 1 and 6 h after surgery, on day-1 and day-2 at 8 a.m.,1 p.m. and 6 p.m. On day-1 and day-2, evolution of quality-of-recovery-15 score was assessed, and timed-up-and-go, 2 and 6 min-walking tests. The noninferiority margin was set as 1 numeric rating scale point 6 h after surgery.

RESULTS

Six hours after surgery, pain scores in group PENG were noninferior to those of group SFIB, with a difference between medians at 0 (95% CI -0.93 to 0.93). There were no significant differences between the groups regarding rest and dynamic pain trajectories during the first 48 postoperative hours, with no significant effects of group (rest P  = 0.800; dynamic P  = 0.708) or interaction between group and time (rest P  = 0.803; dynamic P  = 0.187). Similarly, no significant differences were observed regarding motor and functional recovery as assessed by timed-up-and-go ( P  = 0.197), 2 min ( P  = 0.364), and 6 min walking ( P  = 0.347) tests and quality-of-recovery-15 ( P  = 0.417) score.

CONCLUSION

Following a total hip arthroplasty via the posterolateral approach, a PENG block is noninferior to SFIB regarding postoperative pain control 6 h after surgery, and functional recovery.

TRIAL REGISTRATION

European Clinical Trial Register under EudraCT-number 2020-005126-28 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-005126-28/BE ).

Advances and challenges in neuropathic pain: a narrative review and future directions

Over the past few decades, substantial advances have been made in neuropathic pain clinical research. An updated definition and classification have been agreed. Validated questionnaires have improved the detection and assessment of acute and chronic neuropathic pain; and newer neuropathic pain syndromes associated with COVID-19 have been described. The management of neuropathic pain has moved from empirical to evidence-based medicine. However, appropriately targeting current medications and the successful clinical development of drugs acting on new targets remain challenging. Innovative approaches to improving therapeutic strategies are required. These mainly encompass rational combination therapy, drug repurposing, non-pharmacological approaches (such as neurostimulation techniques), and personalised therapeutic management. This narrative review reports historical and current perspectives regarding the definitions, classification, assessment, and management of neuropathic pain and explores potential avenues for future research.

Transitional Pain Medicine; New Era, New Opportunities, and New Journey

Chronic postsurgical pain (CPSP), also known as persistent postsurgical pain (PPSP), is pain that develops or increases in intensity after a surgical procedure and lasts more than 3 months. Transitional pain medicine is the medical field that focuses on understanding the mechanisms of CPSP and defining risk factors and developing preventive treatments. Unfortunately, one significant challenge is the risk of developing opioid use dependence. Multiple risk factors have been discovered, with the most common, and modifiable, being uncontrolled acute postoperative pain; preoperative anxiety and depression; and preoperative site pain, chronic pain, and opioid use.

Chronic pain after surgery and trauma: current situation and future directions

Chronic post-surgical pain (CPSP) stands as a major health issue. The unchanged incidence over the last two decades underlines both the failure of predictive models developed until now and the lack of efficacy of common “preventive” strategies (pharmacotherapy and regional analgesic techniques) applied in current clinical practice. The recognition of CPSP as a disease and the release of a common definition of the condition is an important progress in the field. CPSP predictive scores exist but none has presently demonstrated an impact on patient care. New clinical directions based on the resolution of postoperative pain, a complex and highly dynamic process supported by individual pain trajectories, argue for predictive models and preventive strategies extended to the subacute pain period i.e. after hospital discharge.

Pain treatment and prophylaxis on pain

PURPOSE OF REVIEW

Also in ambulatory surgery, there will usually be a need for analgesic medication to deal with postoperative pain. Even so, a significant proportion of ambulatory surgery patients have unacceptable postoperative pain, and there is a need for better education in how to provide proper prophylaxis and treatment.

RECENT FINDINGS

Postoperative pain should be addressed both pre, intra- and postoperatively. The management should be with a multimodal nonopioid-based procedure specific guideline for the routine cases. In 10-20% of cases, there will be a need to adjust and supplement the basic guideline with extra analgesic measures. This may be because there are contraindications for a drug in the guideline, the procedure is more extensive than usual or the patient has extra risk factors for strong postoperative pain. Opioids should only be used when needed on top of multimodal nonopioid prophylaxis. Opioids should be with nondepot formulations, titrated to effect in the postoperative care unit and eventually continued only when needed for a few days at maximum.

SUMMARY

Multimodal analgesia should start pre or per-operatively and include paracetamol, nonsteroidal anti-inflammatory drug (NSAID), dexamethasone (or alternative glucocorticoid) and local anaesthetic wound infiltration, unless contraindicated in the individual case. Paracetamol and NSAID should be continued postoperatively, supplemented with opioid on top as needed. Extra analgesia may be considered when appropriate and needed. First-line options include nerve blocks or interfascial plane blocks and i.v. lidocaine infusion. In addition, gabapentinnoids, dexmedetomidine, ketamine infusion and clonidine may be used, but adverse effects of sedation, dizziness and hypotension must be carefully considered in the ambulatory setting.

Effect of suprainguinal fascia iliaca compartment block on postoperative opioid consumption and functional recovery in posterolateral-approached total hip arthroplasty: a single-blind randomized controlled trial

INTRODUCTION

Posterolateral-approached total hip arthroplasty (PLTHA) is followed by moderate to severe postoperative pain. Suprainguinal fascia iliaca compartment block (SFICB) has been proposed as a promising analgesia technique.

METHODS

Data from 86 patients scheduled for PLTHA with spinal anesthesia were analyzed in this prospective randomized controlled trial. Patients were randomly divided into two groups of 43 patients each. As opposed to the control group (group C), ropivacaine group (group R) received additional SFICB using 40 mL of 0.375% ropivacaine. As primary endpoint, blind observers noted total morphine consumption at postoperative 48 hours. Secondary endpoints were pain at rest and mobilization on 0-10 Numeric Rating Scale (rest and dynamic NRS) at fixed time points (1 hour and 6 hours after surgery, and at day 1 and day 2 at 8:00, 13:00 and 18:00 hours), walking performance at day 1 and day 2; postoperative complications including morphine-related side effects or orthostatic intolerance symptoms such as dizziness, nausea, blurred vision or vasovagal syncope.

RESULTS

A 48-hour morphine consumption (mg; median (IQR)) was significantly lower in group R than in group C (11 (8.5-15.5)) vs 26 (21-33.5), p<0001), as well as incidence of morphine-related side effects such as nausea at day 1 (p=0.04) and day 2 (p<0.01). Rest and dynamic NRS were globally significantly lower in group R than in group C (p<0.01). Group R showed less orthostatic intolerance at day 1 (p<0.001) and day 2 (p<0.01) and better functional walking performance at day 1 (<0.001) and day 2 (<0.001).

DISCUSSION

In PLTHA, SFICB provides opioid sparing, improved postoperative pain control, and enhanced functional recovery.

TRIAL REGISTRATION NUMBER

NCT04574479.

Diagnosis, Treatment, and Management of Painful Scar: A Narrative Review

Painful scars can develop after surgery or trauma, with symptoms ranging from a minor itch to intractable allodynia. The problem of the painful scar may involve both intraneural and extraneural structures, requiring a systematic approach to diagnosis and treatment of this neuropathic pain condition that can impact quality of life and function profoundly. In this review, we outline the algorithm for the diagnosis, management, medical and surgical treatment of painful scars.

Evaluation of intraoperative ketamine on the prevention of severe rebound pain upon cessation of peripheral nerve block: a prospective randomised, double-blind, placebo-controlled study

BACKGROUND

Pain after resolution of peripheral nerve block, known as 'rebound pain' (RP), is a major problem in outpatient surgery. The primary objective was to evaluate the benefit of intraoperative ketamine at an anti-hyperalgesic dose on the incidence of rebound pain after upper limb surgery under axillary plexus block in ambulatory patients. The secondary objective was to better understand the rebound pain phenomenon (individual risk factors).

METHODS

In this prospective, double-blind study, patients were randomised to receive either a single dose of i.v. ketamine (0.3 mg kg^-1) or a placebo. Preoperative mechanical temporal summation and central sensitization inventory were applied to question underlying central sensitisation. Pain catastrophising and Douleur Neuropathique 4 questionnaires were used. Rebound pain was defined as pain intensity score >7 (numeric rating scale, 0-10) after block resolution. Postoperative pain was recorded at Days 1, 4, and 30 after discharge.

RESULTS

A total of 109 subjects completed the study, and 40.4% presented with rebound pain. Ketamine administration did not reduce rebound pain incidence or intensity. Temporal summation and central sensitisation inventory scores did not differ between subjects with and without rebound pain. The predictive risk factors were bone surgery (odds ratio [OR]=5.2; confidence interval [CI], 1.9-14.6), severe preoperative pain (OR=4.2; CI, 1.5-11.7), and high pain catastrophising (OR=4.8; CI, 1.0-22.3). At Day 30, the average daily pain was higher in the rebound pain group involving neuropathic characteristics.

CONCLUSION

Ketamine at an anti-hyperalgesic dose showed no benefit on rebound pain development. Although central sensitisation might not be involved, preoperative pain intensity, and catastrophising stand as risk factors. Because rebound pain remains frequent despite adequate procedure-specific postoperative analgesia, future studies should focus on patient-specific pain management.

Chronic Pain Following Fracture-Related Surgery: Posttraumatic Rather Than Postsurgical Origin Promotes Chronification-A Prospective Observational Study With 1-Year Follow-up

BACKGROUND

Chronic posttraumatic/postsurgical pain (CPSP) is common after traumatic or surgical damage. Exposure to both trauma and surgery, with the potential for repeated bone and nerve damage, may increase the risk of CPSP after fracture-related surgery. But the (long-term) incidences of CPSP and neuropathic CPSP and the ensuing burdens are unknown. Therefore, the patients were prospectively assessed within 1 year, and the patient-specific characteristics were explored.

METHODS

Between 2017 and 2018, 127 patients (age: 52.9 ± 17.1 years, male: 55.1%) with traumatic fractures needing osteosynthesis (extremities: 91.3%) were assessed posttrauma (before surgery), postsurgery at days 1 to 5, 6 weeks, 3 and 12 months. The primary outcomes are as follows: incidence at 3 and 12 months of CPSP (defined as pain intensity on a numerical rating scale [NRS: 0-10] ≥3), secondary exploration: neuropathic CPSP (NRS ≥3 and Douleur Neuropathique 4 interview [DN4i] score ≥3 [Douleur Neuropathique interview: 0-7]); burden: quality of life (QoL, the EuroQOL five dimensions questionnaire [EQ-5D-3L] descriptive system); and inter alia, the number of analgesics (trial registration: DRKS00011601).

RESULTS

The incidence of CPSP was 57.1% (52/91, n/N) at 3 and 42.7% (35/82) at 12 months postsurgery, including neuropathic CPSP 7.7% (4/52) and 17.1% (6/35), respectively. Descriptively, posttraumatic higher pain intensity at rest (difference of 0.9 ± 1.8 NRS) and the need for more frequent analgesics (by 34.3%) were associated with CPSP a year after surgery compared to those without. As soon as week 6, these patients had developed descriptively a 15% more impaired QoL, with 25% more impairment after 1 year. The patients with CPSP presented with at least 1 neuropathic symptom 12 months later in 68.6% (24/35) of cases, mainly with an early posttraumatic occurrence (without fulfilling the definition of neuropathic CPSP).

CONCLUSIONS

After early fracture-related surgery, high incidences of CPSP (43%) were prospectively observed 1 year postsurgery, up to approximately 1 in 5 patients who had neuropathic CPSP. At the same time, CPSP was accompanied with an impacted QoL and analgesic dependence, both indicating clinical relevance. Moreover, the high incidence and the early posttraumatic occurrence of more intense pain suggest that the initial fracture-related trauma, rather than the surgical trauma, may predominantly trigger CPSP at Y1 (1 year). Therefore, these exploratory results set the direction of required future research. A future clinical hypothesis might be: treat first what hurts first.

Characteristics and influence on quality of life of new-onset pain in critical COVID-19 survivors

Background

Pain is a clinical feature of COVID‐19, however, data about persistent pain after hospital discharge, especially among ICU survivors is scarce. The aim of this study was to explore the incidence and characteristics of new‐onset pain and its impact on Health‐Related Quality of Life (HRQoL), and to quantify the presence of mood disorders in critically ill COVID‐19 survivors.

Methods

This is a preliminary report of PAIN‐COVID trial (NCT04394169) presenting a descriptive analysis in critically ill COVID‐19 survivors, following in person interview 1 month after hospital discharge. Pain was assessed using the Brief Pain Inventory, the Douleur Neuropathique 4 questionnaire and the Pain Catastrophizing Scale. HRQoL was evaluated with the EQ 5D/5L, and mood disorders with the Hospital Anxiety and Depression Scale (HADS).

Results

From 27 May to 19 July 2020, 203 patients were consecutively screened for eligibility, and 65 were included in this analysis. Of these, 50.8% patients reported new‐onset pain; 38.5% clinically significant pain (numerical rating score ≥3 for average pain intensity); 16.9% neuropathic pain; 4.6% pain catastrophizing thoughts, 44.6% pain in ≥2 body sites and 7.7% widespread pain. Patients with new‐onset pain had a worse EQ‐VAS and EQ index value (p < 0.001). Pain intensity was negatively correlated to both the former (Spearman ρ: −0.546, p < 0.001) and the latter (Spearman ρ: −0.387, p = 0.001). HADS anxiety and depression values equal or above eight were obtained in 10.8% and 7.7% of patients, respectively.

Conclusion

New‐onset pain in critically ill COVID‐19 survivors is frequent, and it is associated with a lower HRQoL.

Trial registration No.: NCT04394169. Registered 19 May 2020. https://clinicaltrials.gov/ct2/show/NCT04394169.

Significance

A substantial proportion of severe COVID‐19 survivors may develop clinically significant persistent pain, post‐intensive care syndrome and chronic ICU‐related pain. Given the number of infections worldwide and the unprecedented size of the population of critical illness survivors, providing information about the incidence of new‐onset pain, its characteristics, and its influence on the patients’ quality of life might help establish and improve pain management strategies.

[Diagnostics and therapy of neuropathic pain]

Neuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system. Scientific studies have shown that neuropathic pain is the result of complex altered signalling processes in the peripheral and central nervous system. Current forms of treatment of neuropathic pain are causally oriented but also aim at symptomatic analgesia by pharmacological and nonpharmacological methods. Furthermore, psychological pain management techniques are used in a supportive role. This review summarizes the contemporary diagnostics of neuropathic pain using frequent diseases as examples and presents the evidence from randomized controlled trials on the treatment of neuropathic pain. Treatment guidelines for pharmacological management of neuropathic pain include evidence-based use of antidepressants, anticonvulsants, opioids, capsaicin and lidocaine.

Capsaicin 179-mg cutaneous patch in the treatment of post-surgical neuropathic pain: a scoping review of current evidence and place in therapy

INTRODUCTION

The use of topical agents has been suggested for post-surgical neuropathic pain. A high-concentration capsaicin 179-mg cutaneous patch (Qutenza™) is licensed in adults for chronic neuropathic pain in the EU, and neuropathic pain with post-herpetic neuralgia and neuropathic pain with diabetic peripheral neuropathy in the USA. This article aims to describe the use of a topical capsaicin 179-mg cutaneous patch in the treatment of PSNP.

AREA COVERED

This narrative review presents the relevant clinical aspects of the use of a topical capsaicin 179-mg cutaneous patch for the treatment of post-surgical neuropathic pain (PSNP). Randomized control trials, observational studies, case series, and reports investigating the clinical use of the capsaicin patch were searched through MEDLINE, EMBASE, AMED, Cochrane Library, CINAHL, Web of Science, and ROAD databases. Trials from citation lists of reviewed articles and hand-searching were added. The search concluded in September 2020. 10/20 articles were considered.

EXPERT OPINION

Some clinical studies demonstrated the efficacy of the capsaicin 179-mg patch in PSNP as monotherapy and concomitant treatment with oral treatments. This topical treatment of PSNP is better tolerated and accepted compared with systemic treatments. To maximize the effectiveness of the treatment, correct administration recommendations should be followed.

Neuropathic component of postoperative pain for predicting post-caesarean chronic pain at three months. A prospective observational study

BACKGROUND

Recent investigations have showed that caesarean section (CS) might be a cause of chronic pain, with a consequent decrease in quality of life.

METHODS

Prospective observational study in a Spanish tertiary hospital. Main Outcome measure was to assess early neuropathic characteristics of pain (DN2 score ≥ 3) one week after CS as a potential risk factor for post-caesarean section chronic pain (PCSCP) at three months. Secondary outcome was to identify other risk factors. 610 consecutive consenting patients undergoing CS were interviewed preoperatively, at discharge from recovery room and 24h postoperatively. Telephone follow-up interviews were conducted one week, three months and twelve months following surgery.

RESULTS

We analysed 597 consecutive patients. The incidence of PCSCP at three and twelve postoperative months were 6.2% and 1% respectively. Subjects with NRS score superior to five on movement one week after CS presented higher incidence of PCSCP (NRS superior to five: 19 (52,2%); NRS equal or lower to five: 172 (30,9%); p=0,009). On multivariate analysis neuropathic pain one week after CS was associated with a higher risk of PCSCP (AOR: 1.63 (95% CI: 1.26-2.11; p<0.001). Other identified risk factors for PCSCP were: uterine exteriorization during CS (AOR: 3.89 (95% CI 1.25-12.10; p=0.019) and a lower gestational age (AOR: 0.87 (95% CI: 0.78-0.96; p=0.008).

CONCLUSIONS

Incidence of PCSCP at three and twelve postoperative months was low, 6.2% and 1% respectively. Early neuropathic characteristics of pain after one week measured by neuropathic pain questionnaire, consisting of two questions (DN2) ≥ 3/7 could be used to identify patients at risk for chronic post-surgical pain and develop preventive strategies.

[Prediction and prevention of chronic postoperative pain]

Chronic postoperative pain has been identified as a major medical and socioeconomic problem. A prevention of the chronification processes is potentially possible and preventive treatment could start early (e.g. preoperatively). So far, however, evidence for the effectiveness of preventive strategies is basically low. Important reasons for this dilemma are the lack of appropriate risk assessment as well as effective and mechanism-based preventive (procedure-sepcific) strategies for the chronification process, a lack of stratification of treatment approaches and a so far barely investigated combination of various treatment approaches. In this review article recent findings on the appropriate identification of patients at risk for developing postoperative chronic pain are presented, predictive models for the valid estimation of the individual risk of patients are assessed and studies on pharmaceutical and regional analgesia techniques influencing the pain chronification process are discussed. As a chronification process is, however, extremely complex and dynamic and also necessitates adaptation of the prevention during the course of the process, only combinations of treatment, interdisciplinary and if necessary even longer term approaches might be successful. Future studies are needed to address with which preventive treatment strategies and in which patients chronic pain after surgery can effectively be prevented.

A Prospective Observational Study of Multivisceral Resection for Retroperitoneal Sarcoma: Clinical and Patient-Reported Outcomes 1 Year After Surgery

BACKGROUND

Primary retroperitoneal sarcoma (RPS) may require multivisceral resection (MVR). Clinical outcome (morbidity and renal function) and quality of life (QoL) are not as well reported as the oncologic outcome.

METHODS

Patients with primary RPS who underwent surgery between 2014 and 2016 were prospectively enrolled in an observational longitudinal study. At baseline, then at 4 and 12 months, the study measured Clavien-Dindo morbidity, estimated glomerular filtration rate (EGFR), EORTC QLQ-C30, QLQ-CR29, DN4 (neuropathic pain [NP]), lower-extremity functional scale (LEFS), and the brief pain inventory. The primary end point was the difference in global health status (GHS/QoL). The secondary end points were EGFR changes, difference in other QLQ-C30 scales, pain intensity, NP, and LEFS. The study is registered at ClinTrials.gov (NCT03480399).

RESULTS

Of 74 patients, 58 were evaluable. Morbidity grade 3 or higher was 24.1%, and mortality was 1.3%. After nephrectomy, the mean 1-year EGFR change was -33.9%. The GHS/QoL at baseline was 58.6 and had increased of 6.9 points at 1 year, comparable with that of the general population. A transient worsening in pain and diarrhea had recovered at 12 months. Average pain was mild and did not differ at 12 months. However, NP was found in 41.4% of the patients and was significantly associated with resection of the psoas muscle. At baseline, LEFS was already lower than the normative value, and worsening after surgery was not clinically relevant.

CONCLUSION

A QoL measure after MVR in primary RPS is complex and requires multiple tools. Whereas overall MVR is safe and associated with an improvement in GHS/QoL, chronic NP is frequent and deserves specific attention. Pre-surgery rehabilitation tracks may help to prevent or reduce chronic NP.

Chronic neuropathic pain after traumatic peripheral nerve injuries in the upper extremity: prevalence, demographic and surgical determinants, impact on health and on pain medication

Background and aims Aside from the long term side effects of a nerve injury in the upper extremity with devastating consequences there is often the problem of chronic neuropathic pain. The studies concerning the prevalence of persistent pain of neuropathic origin after peripheral nerve injuries are sparse. The prevalence and risk factors associated with chronic neuropathic pain after nerve injuries in the upper extremity were assessed. Methods A standardized data collection template was employed prospectively and retrospectively for all patients with traumatic nerve injuries accepted at the Hand Surgery Department, Uppsala, Sweden between 2010 and 2018. The template included demographic data, pain diagnosis, type of injured nerve, level of injury, date of the lesion and repair, type of procedure, reoperation, time since the procedure, S-LANSS questionnaire (Self report-Leeds Assessment of Neuropathic Symptoms and Signs), RAND-36 (Item short form health survey), QuickDASH (Disability of Shoulder, Arm and Hand) and additional questionnaires concerned medication, pain intensity were sent to 1,051 patients with nerve injuries. Partial proportional odds models were used to investigate the association between persistent pain and potential predictors. Results More than half of the patients undergoing a surgical procedure developed persistent pain. Prevalence of neuropathic pain was 73% of the patients with pain (S-LANSS ≥ 12 or more). Multivariate analysis indicated that injury of a major nerve OR 1.6 (p = 0.013), years from surgery OR 0.91 (p = 0.01), younger age OR 0.7 (p < 0.001), were the main factors for predicting pain after surgery. The type of the nerve injured was the strongest predictor for chronic pain with major nerves associated with more pain (p = 0.019). Conclusions A high prevalence of chronic pain and neuropathic pain with a negative impact on quality of life and disability were found in patients after traumatic nerve injury. Major nerve injury, younger age and less time from surgery were predictors for chronic pain.

Neuropathic pain at diagnosis of head and neck squamous cell carcinoma

OBJECTIVE

To assess the prevalence and characteristics of neuropathic pain (NP) at diagnosis of head and neck squamous cell carcinoma (HNSCC) and its impact on nutritional status and treatment tolerance.

MATERIALS AND METHODS

Patients treated for HNSCC between January 1, 2018 and January 30, 2019 were included. Pain was assessed prospectively on the DN2 and NSPI scales. Epidemiological characteristics, nutritional status and treatment tolerance were collected. Two groups were distinguished according to absence or presence of neuropathic pain (NP-, NP+).

RESULTS

Sixty patients were included. NP prevalence at diagnosis was 54%, mainly involving locally advanced oral cavity and oropharyngeal tumors. There was a significant intergroup difference in nutritional status, with 62% malnutrition in NP+ versus 32% in NP- (p=0.0321). There was no such difference in tolerance.

CONCLUSION

NP is frequent at diagnosis of HNSCC. Early diagnosis on a simple validated score can help improve quality of life and nutritional status.

Acute and chronic neuropathic pain profiles after video-assisted thoracic surgery: A prospective study

Acute postsurgical pain, probably including acute neuropathic pain (ANeP), starts at the early postoperative period, and chronic postsurgical pain including chronic neuropathic pain (CNeP) persists at least 3 months after surgery. Although it must be important for prevention and treatment of acute and chronic postoperative pain to reveal the time course of postoperative neuropathic characteristics, a neuropathic pain profile after surgery has not been evaluated.Pain status at the surgical site in adult patients who underwent video-assisted thoracic surgery (VATS) for lung cancer was prospectively assessed until 12 months after surgery. Neuropathic characteristics were assessed using the Douleur Neuropathique 4 (DN4) questionnaire until 6 days after surgery and the DN2 questionnaire throughout the study.Twenty-seven patients were enrolled in this study. Pain intensity at surgical sites were significantly higher at 1 and 6 days after surgery during resting state, and were also significantly higher at 3, 6, and 12 months after surgery during movement than those before surgery. The incidence of ANeP was 33.3% at 1 day, and 18.5% at 6 days after surgery. The incidence of CNeP decreased to 12.5% at 3 months, 5.0% at 6 months, and 0.0% at 12 months after surgery. The number of neuropathic characteristics, assessed by DN2 scores, significantly increased at 1 and 6 days after surgery, compared to those before surgery. DN2 scores at 3, 6, and 12 months after surgery, however, showed no significant differences compared to those before surgery.In patients with acute postsurgical pain, 20% to 30% of patients show ANeP characteristics, and the incidence of CNeP gradually decreases after VATS in patients with chronic postsurgical pain.

Chronified Pain Following Operative Procedures

BACKGROUND

Over 18 million operative procedures are performed each year in Germany alone. Approximately 10% of surgical patients develop moderate to severe chronic post-surgical pain (CPSP), which can severely impair their quality of life. The pain must persist for at least three months to be called chronic; pain that arises after a symptom-free interval is not excluded. The perioperative use of local anesthetic agents may lessen the incidence of CPSP.

METHODS

We selectively reviewed the pertinent literature, including two current Cochrane Reviews. Local and regional anesthetic techniques are discussed, as is the intravenous administration of lidocaine.

RESULTS

The main risk factors for CPSP are pre-existing (preoperative) chronic pain, opioid intake, a pain-related catastrophizing tendency, intraoperative nerve injury, and severe acute postoperative pain. CPSP is reported to be especially common after thoracic surgery, breast surgery, amputations, and orthopedic procedures. Local and regional anesthetic techniques have been shown to significantly lower the incidence of CPSP after thoracotomy (number needed to treat for an additional beneficial outcome [NNTB] = 7), breast cancer surgery (NNTB = 7), and cesarean section (NNTB = 19). Intravenous lidocaine also lowers the incidence of CPSP after various types of procedures.

CONCLUSION

Local and regional anesthetic techniques and intravenous lidocaine lower the incidence of CPSP after certain types of operative procedures. The intravenous administration of lidocaine to prevent CPSP is off label and requires the patient's informed consent. The evidence for the measures presented here is of low to medium quality.

Prevention and Treatment of Chronic Postsurgical Pain: A Narrative Review

Chronic postsurgical pain affects between 5 and 75% of patients, often with an adverse impact on quality of life. While the transition of acute to chronic pain is a complex process-involving multiple mechanisms at different levels-the current strategies for prevention have primarily been restricted to perioperative pharmacological interventions. In the present paper, we first present an up-to-date narrative literature review of these interventions. In the second section, we develop several ways by which we could overcome the limitations of the current approaches and enhance the outcome of our surgical patients, including the better identification of individual risk factors, tailoring treatment to individual patients, and improved acute and subacute pain evaluation and management. The third and final section covers the treatment of established CPSP. Given that evidence for the current therapeutic options is limited, we need high-quality trials studying multimodal interventions matched to pain characteristics.

'Why me?' The problem of chronic pain after surgery

Chronic postsurgical pain (CPSP) has become a health priority and is scheduled to be included in the upcoming version of the International Classification of Diseases, 11th Revision (ICD-11). Recent studies on CPSP show unchanged prevalence despite progress made in fundamental research about underlying pathophysiological mechanisms. Nevertheless, clinical research has allowed better understanding of some CPSP aspects such as the development of neuropathic CPSP. Actually, some improvements are ongoing such as a refined definition and the assessment of CPSP in vulnerable populations, for example, paediatric patients. Pain after surgery, its resolution or its transition to CPSP is a dynamic process that reinforces the necessity of longitudinal assessment and management. In other words, CPSP can be called 'perioperative medicine'.