Does pain intensity after total knee arthroplasty depend on somatosensory functioning in knee osteoarthritis patients? A prospective cohort study

The objective of this study is to determine whether the change in pain intensity over time differs between somatosensory functioning evolution profiles in knee osteoarthritis (KOA) patients undergoing total knee arthroplasty (TKA). This longitudinal prospective cohort study, conducted between March 2018 and July 2023, included KOA patients undergoing TKA in four hospitals in Belgium and the Netherlands. The evolution of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale pain over time (baseline, 3 months, and 1 year post-TKA scores) was the outcome variable. The evolution scores of quantitative sensory testing (QST) and Central Sensitization Inventory (CSI) over time (baseline and 1 year post-TKA scores) were used to make subgroups. Participants were divided into separate normal, recovered, and persistent disturbed somatosensory subgroups based on the CSI, local and widespread pressure pain threshold [PPT] and heat allodynia, temporal summation [TS], and conditioned pain modulation [CPM]. Linear mixed model analyses were performed. Two hundred twenty-three participants were included. The persistent disturbed somatosensory functioning group had less pronounced pain improvement (based on CSI and local heat allodynia) and worse pain scores 1 year post-TKA (based on CSI, local PPT and heat allodynia, and TS) compared to the normal somatosensory functioning group. This persistent group also had worse pain scores 1 year post-TKA compared to the recovered group (based on CSI). The study suggests the presence of a "centrally driven central sensitization" subgroup in KOA patients awaiting TKA in four of seven grouping variables, comprising their less pain improvement or worse pain score after TKA. Future research should validate these findings further. The protocol is registered at clinicaltrials.gov (NCT05380648).

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.

Preoperative Versus Perioperative Risk Factors for Delayed Pain and Opioid Cessation After Total Joint Arthroplasty: A Prospective Cohort Study

INTRODUCTION

The evolution of pre- versus postoperative risk factors remains unknown in the development of persistent postoperative pain and opioid use. We identified preoperative versus comprehensive perioperative models of delayed pain and opioid cessation after total joint arthroplasty including time-varying postoperative changes in emotional distress. We hypothesized that time-varying longitudinal measures of postoperative psychological distress, as well as pre- and postoperative use of opioids would be the most significant risk factors for both outcomes.

METHODS

A prospective cohort of 188 patients undergoing total hip or knee arthroplasty at Stanford Hospital completed baseline pain, opioid use, and emotional distress assessments. After surgery, a modified Brief Pain Inventory was assessed daily for 3 months, weekly thereafter up to 6 months, and monthly thereafter up to 1 year. Emotional distress and pain catastrophizing were assessed weekly to 6 months, then monthly thereafter. Stepwise multivariate time-varying Cox regression modeled preoperative variables alone, followed by all perioperative variables (before and after surgery) with time to postoperative opioid and pain cessation.

RESULTS

The median time to opioid and pain cessation was 54 and 152 days, respectively. Preoperative total daily oral morphine equivalent use (hazard ratio-HR 0.97; 95% confidence interval-CI 0.96-0.98) was significantly associated with delayed postoperative opioid cessation in the perioperative model. In contrast, time-varying postoperative factors: elevated PROMIS (Patient-Reported Outcomes Measurement Information System) depression scores (HR 0.92; 95% CI 0.87-0.98), and higher Pain Catastrophizing Scale scores (HR 0.85; 95% CI 0.75-0.97) were independently associated with delayed postoperative pain resolution in the perioperative model.

CONCLUSIONS

These findings highlight preoperative opioid use as a key determinant of delayed postoperative opioid cessation, while postoperative elevations in depressive symptoms and pain catastrophizing are associated with persistent pain after total joint arthroplasty providing the rationale for continued risk stratification before and after surgery to identify patients at highest risk for these distinct outcomes. Interventions targeting these perioperative risk factors may prevent prolonged postoperative pain and opioid use.

Can perioperative psychological interventions reduce chronic pain after surgery?

Chronic post-surgical pain is a relatively common adverse effect following surgery. Several prognostic factors for chronic post-surgical pain have been identified, including psychological states and traits. Psychological factors are modifiable, and perioperative psychological interventions may reduce the incidence of chronic post-surgical pain. A meta-analysis showed preliminary evidence for the benefits of such interventions for the prevention of chronic post-surgical pain. Further research must be conducted to better understand the specific type, intensity, duration and timing of interventions that are most effective. The number of studies in this area has recently increased, with additional randomised controlled trials currently being carried out, which may allow for the development of more robust conclusions in the coming years. In order to implement perioperative psychological care alongside routine surgical interventions, efficient and accessible interventions should be available. In addition, demonstration of cost-effectiveness may be a prerequisite for wider adoption of perioperative psychological interventions in regular healthcare. Offering psychological interventions selectively to patients at risk of chronic post-surgical pain could be a means to increase cost-effectiveness. Stepped-care approaches should also be considered, where the intensity of psychological support is adapted to the needs of the patient.

Characteristics and distribution of chronic pain after mastectomy and breast reconstruction: a long-term prospective cohort study

PURPOSE

Chronic pain following breast surgery is a concern for breast cancer survivors; however, few studies have investigated the localization of persistent postoperative pain. We conducted this study to identify the location of pain following breast reconstruction.

METHODS

A total of 213 Japanese women undergoing mastectomy only or breast reconstruction with a tissue expander/implant (TE/Imp) or a deep inferior epigastric perforator (DIEP) flap were enrolled in the study. Questionnaires related to pain location were sent to patients at the end of postoperative year (POY) 1 and POY 5. Multiple comparisons of the types of operation and cross-tabulation were made between the two time points.

RESULTS

Surveys were completed by 107 of the women. Severe pain in the upper medial breast was significantly more common in POY 1 after DIEP reconstruction than after mastectomy only (P = 0.01), whereas abdominal pain was worse in POY 5 after DIEP reconstruction than after mastectomy only (P = 0.04). Pain in the medial arm and axilla had resolved better after TE/Imp (P = 0.03) and DIEP reconstruction (P = 0.01) than after mastectomy only by POY 5, but the difference between TE/Imp and DIEP reconstruction was not significant.

CONCLUSIONS

These results show that localization of prolonged postoperative pain following breast reconstruction differs depending on the surgical strategy.

Risk factors associated with chronic pain after mastectomy: a prospective study with a 5-year follow-up in Japan

BACKGROUND

Chronic pain is a major complication following breast surgery including breast reconstruction. We previously examined prospective patient-specific and medical/surgical factors that predict chronic pain a year after breast surgery in the Japanese population. Five-year survivorship is essential for breast cancer patients. This report is a 4-year follow-up study following the previous research.

METHODS

A follow-up observation study was performed 5 years after breast operations. The subjects were patients who underwent breast surgery, including tissue expander/implant (TE/implant), DIEP procedures and mastectomy only. Pain at 5 years was assessed using the Japanese Version of the Short-Form McGill Pain Questionnaire (SF-MPQ-JV). A multiple linear regression model was used to examine the relationships of clinical factors with chronic pain.

RESULTS

Questionnaires were completed by 132 subjects. No factor related to chronic pain was significantly related to the MPQ pain ratings. Among patient characteristics, a psychotic or neurological medical history was related to significantly lower visual analog scale (p = 0.02) and present pain index (p = 0.04) scores. A history of chemotherapy and/or hormone therapy was significantly associated with the frequency of use of pain medication postoperatively (p = 0.05) and effect on the social life of the patients (p = 0.02).

CONCLUSIONS

A psychotic or neurological history and a history of chemotherapy and/or hormone therapy were identified as risk factors for chronic pain after breast surgery, but the type of operation was not associated with chronic pain.

Effect of lidocaine perioperative infusion on chronic postsurgical pain in patients undergoing thoracoscopic radical pneumonectomy

BACKGROUND

Thoracoscopic radical pneumonectomy is associated with a high incidence of postoperative chronic pain. Studies on the benefits of lidocaine intravenous infusion during the perioperative period were still controversial in thoracoscopic surgery.

METHODS

Sixty-four lung cancer patients scheduled for thoracoscopic radical pneumonectomy were randomly divided into two groups: normal saline group (control group) or lidocaine group. In the lidocaine group, 1.5 mg/kg lidocaine was administered during the anesthesia induction, and 2 mg·kg^-1·h^-1 lidocaine was continuously intravenous infused until the end of the surgery. After the surgery, a mixture of 2 μg/kg sufentanil and 10 mg/kg lidocaine was continuously intravenous infused by postoperative patient-controlled intravenous analgesia pump (100 ml). In the control group, the same volume of normal saline was administered according to the calculation of lidocaine during anesthesia induction, maintenance and postoperative patient-controlled intravenous analgesia. The primary outcome was the incidence of chronic postoperative pain at 3 months after the surgery. The secondary outcomes include the incidence of chronic postoperative pain at 6 months after the surgery; the effect of lidocaine on postoperative pain within the first 24 and 48 h; total amount of sufentanil administered during entire procedure and the number of PCA triggers within 48 h after surgery.

RESULTS

Compared with the control group, the incidence of chronic pain at 3 months after the surgery was significantly lower (13 cases, 46.4% vs. 6 cases, 20.7%, p < 0.05), but no significant difference at 6 months between two group. The cumulative dosage of sufentanil in perioperative period was significantly lower (149.64 ± 18.20 μg vs. 139.47 ± 16.75 μg) (p < 0.05), and the number of PCA triggers (8.21 ± 4.37 vs. 5.83 ± 4.12, p < 0.05) was significantly greater in the control group. The NRS pain scores at 24 h (1.68 ± 0.72 vs. 1.90 ± 0.86) and 48 h (1.21 ± 0.42 vs. 1.20 ± 0.41) after the operation were no significant difference.

CONCLUSION

Perioperative infusion lidocaine significantly reduced the number of PCA triggers and the incidence of chronic postoperative pain at 3 months after the thoracoscopic radical pneumonectomy.

TRIAL REGISTRATION

http://www.chictr.org.cn : ChiCTR1900024759, frist registration date 26/07/2019.

Identifying Patients at High Risk of Chronic Pain After Video-Assisted Thoracoscopic Surgery Using Thermal Quantitative Sensory Testing

OBJECTIVE

To examine whether perioperative thermal quantitative sensory testing could be used to identify patients at high risk of chronic pain after video-assisted thoracoscopic surgery (VATS).

DESIGN

A single-center, prospective, observational study.

SETTING

At the Peking University People's Hospital.

PARTICIPANTS

A total of 111 patients scheduled to undergo VATS were enrolled.

INTERVENTIONS

Quantitative sensory testing was conducted at the anterior intercostal incision prior to surgery and after chest tube removal.

MEASUREMENTS AND MAIN RESULTS

The patient's chronic pain was assessed at 3 months after surgery using a questionnaire. The incidence of chronic pain was 35 out of 107 evaluable patients (32.7%). Among the 35 patients with chronic pain, 26 had features characteristic of neuropathic pain (74.3%). Compared to the patients without chronic pain, subjects with chronic pain had a significantly greater perioperative change in cold pain threshold (CPT; p = 0.032), but not cold detection threshold, warm detection threshold, and hot pain threshold . In the multivariate regression, perioperative CPT change was associated with chronic pain after VATS (odds ratio = 1.043, p = 0.026).

CONCLUSIONS

Chronic pain after VATS is typically neuropathic. The change in perioperative CPT at the incision site may help to identify patients at higher risk of chronic pain after VATS.

The painful shoulder arthroplasty: appropriate work-up and review of interventional pain treatments

Shoulder arthroplasty is a successful surgical procedure for several conditions when patients become refractory to conservative management modalities. Unfortunately, some patients experience persistent chronic pain after shoulder arthroplasty. These individuals should undergo a comprehensive evaluation by an orthopedic surgeon to determine whether structural pathology is responsible for the pain and to decide whether reoperation is indicated. At times, a surgical solution does not exist. In these circumstances, a thorough and specific plan for the management of persistent chronic pain should be developed and instituted. In this article, we review common reasons for persistent pain after shoulder arthroplasty and outline the evaluation of the painful shoulder arthroplasty. We then provide a thorough review of interventional pain management strategies. Finally, we hypothesize developments in our field that might provide better outcomes in the future for patients suffering with chronic intractable pain after shoulder arthroplasty.

Perioperative Dexmedetomidine or Lidocaine Infusion for the Prevention of Chronic Postoperative and Neuropathic Pain After Gynecological Surgery: A Randomized, Placebo-Controlled, Double-Blind Study

Introduction

The transition of acute to chronic postoperative pain (CPP) remains a significant burden to the rehabilitation of patients. The research for adjuvants to prevent CPP continues; among others, dexmedetomidine and lidocaine seem promising agents.

Methods

This is a long-term follow-up of a randomized, placebo-controlled, double-blind study on women who underwent open abdominal gynecological surgery and received dexmedetomidine or lidocaine or placebo infusion perioperatively (n = 81). The effect of these adjuvants on the development of CPP and neuropathic pain was assessed during a 12-month follow-up. Eighty-one (81) women ASA I–II, aged between 30 and 70 years, were randomly assigned to receive either dexmedetomidine (DEX group) or lidocaine (LIDO group) or placebo (CONTROL group) perioperatively. Before anesthesia induction, all patients received a loading intravenous dose of either 0.6 μg/kg dexmedetomidine or 1.5 mg/kg lidocaine or placebo, followed by 0.6 μg/kg/h dexmedetomidine or 1.5 mg/kg/h lidocaine or placebo until last suture. Patients were followed up to obtain the long-term outcomes at 3, 6, and 12 months. At these time-points, pain intensity was assessed with the Numerical Rating Scale, (NRS: 0–10) and the development of neuropathic elements with the Douleur Neuropathique 4 (DN4) score. Prognostic parameters that could affect chronic pain and its components were also identified.

Results

Data from 74 women were analyzed. Dexmedetomidine significantly reduced NRS scores comparing to placebo at 3 months (p = 0.018), while at 6 months, lidocaine was found superior to placebo (p = 0.02), but not to dexmedetomidine, in preventing neuropathic pain (DN4 < 4). Regarding secondary endpoints, higher NRS cough scores at 48 h were associated with statistically significant NRS and DN4 scores at 3, 6, and 12 months (p < 0.02). At 6 months, a statistically significant correlation was also found between higher NRS values and older age (p = 0.020).

Conclusions

Dexmedetomidine was superior to placebo regarding the duration and severity of CPP, while lidocaine exhibited a protective effect against neuropathic elements of CPP.

Trial registration

ClinicalTrials.gov identifier, NCT03363425.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00361-5.

Repeated Endomorphin Analogue MEL-0614 Reduces Tolerance and Improves Chronic Postoperative Pain without Modulating the P2X7R Signaling Pathway

The clinical treatment of chronic postoperative pain (CPSP) remains challenging. The side effects of chronic morphine treatment limit its clinical application. MEL-0614, a novel endomorphin analogue that is highly selective and agonistic for μ opioid receptor (MOR), produces a more powerful analgesic effect than that of morphine. In this study, we explored the difference in antinociceptive tolerance and related mechanisms between MEL-0614 and morphine in CPSP induced in a skin/muscle incision and retraction (SMIR) mice model. We found that acute administration of MEL-0614 (1, 3, 5, and 10 nmol, i.t.) produced a dose-dependent analgesic effect that was superior to that of morphine in the SMIR mice model. Long-term MEL-0614 treatment (10 nmol, i.t.) did not induce tolerance compared with morphine. Notably, tolerance induced by morphine could be greatly prevented and/or inhibited via cross-administration or coadministration between MEL-0614 and morphine. In addition, MEL-0614 accelerated the recovery of postoperative pain, whereas morphine aggravated postoperative pain and prolonged its recovery time regardless of preoperative or postoperative treatment. In addition, MEL-0614 did not activate microglia and the P2X7R signaling pathway and showed reduced expression iba1 and P2X7R compared with that observed after morphine administration. Release of inflammatory factors was induced by continued administration of morphine during SMIR surgery, but MEL-0614 did not promote the activation of inflammatory factors. Our results showed that MEL-0614 has superior analgesic effects in CPSP and leads to tolerance to a lesser degree than morphine. Further, MEL-0614 may be used as a promising treatment option for the long-term treatment in CPSP.

Chronic Postoperative Pain After Hysterectomy for Endometrial Cancer: A Metabolic Profiling Study

INTRODUCTION

One out of seven women will develop a state of chronic postoperative pain following robot-assisted hysterectomy for endometrial cancer. Recently, metabolic studies have indicated that circulating lipids and lipoproteins could act as nociceptive modulators and thereby influence the induction and perpetuation of pain. The objectives of this explorative study were (1) to examine the preoperative serologic variations in concentrations of lipids, lipoproteins, and various low-molecular metabolites in patients with and without chronic postoperative pain after robot-assisted hysterectomy and (2) to explore if any of these serological biomarkers were predictive for development of chronic postoperative pain.

MATERIALS AND METHODS

The study was designed as a nested case-control study within a cohort of women treated for endometrial cancer with robot-assisted laparoscopic hysterectomy. Twenty-six women with chronic postoperative pain were matched on age and body mass index with fifty-two controls without chronic postoperative pain, and metabolic profiling of preoperatively drawn blood samples from a biobank was performed by means of nuclear magnetic resonance spectroscopy.

RESULTS

Nineteen metabolites, including cholesterol, cholesteryl ester, linoleic acid, phospholipids, lipids, and triglycerides had statistically significant higher concentrations in a subgroup of patients who would develop chronic postoperative pain on a later stage compared to the group of patients who would not develop chronic postoperative pain (p < 0.05). A sparse Partial Least Squares-Discriminant Analysis model explained 38.1% of the variance and had a predictive accuracy of 73.1%.

CONCLUSIONS

This explorative study substantiates the hypothesis that certain lipids, lipoproteins, and fatty acids are associated with chronic postoperative pain.

Case series of recurrent inguinal hernia after primary TREPP repair: re-TREPP seems feasible and safe

•

Recurrent inguinal hernias are preferably treated via an alternative route, e.g. posterior after anterior.

•

Endoscopic preperitoneal repair techniques are common for groin hernias after Lichtenstein’s plasty.

•

The TREPP technique is a minimal access, open variant of these preperitoneal techniques.

•

The TREPP technique seems to be a safe and feasible technique to use for recurrence after previous TREPP for inguinal hernia repair.

Introduction

The Trans REctussheath PrePeritoneal (TREPP) mesh repair was introduced in 2006 to decrease the risk of postoperative inguinal pain in hernia surgery. For the repair of a recurrent inguinal hernia after a primary TREPP an alternative open anterior route (Lichtenstein) may seem the most logical option, but coincides with an increased risk of chronic postoperative inguinal pain. Therefore, this study aimed to evaluate the feasibility of a second TREPP procedure to repair a recurrent inguinal hernia after an initial TREPP repair.

Methods

Consecutive patients with a recurrent inguinal hernia after a primary TREPP, repaired by a re-TREPP were retrospectively included in the study. Data, retrieved from the electronic patient files, were combined with the clinical findings at the outpatient department where the patients were physically investigated according to a priorly written and registered protocol.

Results

Overall about 1800 TREPPs were performed between 2006 and 2013. Since the introduction of TREPP in 2006, 40 patients presented with a recurrence in our center. From this group 19 patients were re-operated with the TREPP technique. No intraoperative complications occurred. There was one conversion from re-TREPP to Lichtenstein and no re-recurrences occurred to date. Ten out of 19 patients could be clinically evaluated with a mean follow-up period of 37 months (range 11–95). None of these patients (n=10) complained of chronic postoperative inguinal pain. Two patients reported discomfort. One patient died non procedure related, three weeks after re-TREPP of sudden cardiac death.

Conclusion

These first experiences with re-TREPP for secondary inguinal hernia repair are encouraging for the aspects of feasibility and safety, particularly in experienced surgical hands.

A novel treatment for chronic opioid use after surgery

In a recent article from the Center for Disease Control, the authors addressed the current opioid epidemic in America and emphasized the importance of utilizing non-opioid analgesic alternatives to opioid medication for treating chronic pain. In cases where non-opioid analgesic drugs alone have failed to produce adequate pain relief, these authors suggested that non-pharmacologic therapies should also be considered. This Case Series describes a pilot study designed to evaluate a novel non-pharmacologic approach to treating long-standing (>1year) opioid dependency. The therapy involved the use of a high intensity cold laser device to treat three patients who had become addicted to prescription opioid-containing analgesic medication for treating chronic (residual) pain after a major operation. After receiving a series of 8-12 treatment sessions lasting 20-40min to the painful surgical area over a 3-4week period of time with the high intensity (42W) Phoenix Thera-lase laser device, an FDA-approved Class IV cold laser, these patients were able to discontinue their use of all oral opioid-containing analgesic medications and resume their normal activities of daily living. At a follow-up evaluation 1-2months after their last laser treatment, these patients reported that they have been able to control their pain with over-the-counter non-opioid analgesics and they have remained largely opioid-free. Further larger-scale studies are needed to verify these preliminary findings with this powerful cold laser in treating opioid-dependent patients.

[Pain after major elective orthopedic surgery of the lower limb and type of anesthesia: does it matter?]

BACKGROUND AND OBJECTIVES

Total knee arthroplasty and total hip arthroplasty are associated with chronic pain development. Of the studies focusing on perioperative factors for chronic pain, few have focused on the differences that might arise from the anesthesia type performed during surgery.

METHODS

This was a prospective observational study performed between July 2014 and March 2015 with patients undergoing unilateral elective total knee arthroplasty (TKA) or total hip arthroplasty (THA) for osteoarthritis. Data collection and pain evaluation questionnaires were performed in three different moments: preoperatively, 24hours postoperatively and at 6 months after surgery. To characterize pain, Brief Pain Inventory (BPI) was used and SF-12v2 Health survey was used to further evaluate the sample's health status.

RESULTS

Forty and three patients were enrolled: 25.6% men and 74.4% women, 51,2% for total knee arthroplasty and48.8% for total hip arthroplasty, with a mean age of 68 years. Surgeries were performed in 25.6% of patients under general anesthesia, 55.8% under neuraxial anesthesia and 18.6% under combined anesthesia. Postoperatively, neuraxial anesthesia had a better pain control. Comparing pain evolution between anesthesia groups, neuraxial anesthesia was associated with a decrease in "worst", "medium" and "now" pain at six months. Combined anesthesia was associated with a decrease of "medium" pain scores at six months. Of the three groups, only those in neuraxial group showed a decrease in level of pain interference in "walking ability". TKA, "worst" pain preoperatively and general were predictors of pain development at six months.

CONCLUSIONS

Patients with gonarthrosis and severe pain preoperatively may benefit from individualized pre- and intraoperative care, particularly preoperative analgesia and neuraxial anesthesia.

Pain after major elective orthopedic surgery of the lower limb and type of anesthesia: does it matter?

BACKGROUND AND OBJECTIVES

Total knee arthroplasty and total hip arthroplasty are associated with chronic pain development. Of the studies focusing on perioperative factors for chronic pain, few have focused on the differences that might arise from the anesthesia type performed during surgery.

METHODS

This was a prospective observational study performed between July 2014 and March 2015 with patients undergoing unilateral elective total knee arthroplasty (TKA) or total hip arthroplasty (THA) for osteoarthritis. Data collection and pain evaluation questionnaires were performed in three different moments: preoperatively, 24 hours postoperatively and at 6 months after surgery. To characterize pain, Brief Pain Inventory (BPI) was used and SF-12v2 Health survey was used to further evaluate the sample's health status.

RESULTS

Forty and three patients were enrolled: 25.6% men and 74.4% women, 51,2% for total knee arthroplasty and48.8% for total hip arthroplasty, with a mean age of 68 years. Surgeries were performed in 25.6% of patients under general anesthesia, 55.8% under neuraxial anesthesia and 18.6% under combined anesthesia. Postoperatively, neuraxial anesthesia had a better pain control. Comparing pain evolution between anesthesia groups, neuraxial anesthesia was associated with a decrease in "worst", "medium" and "now" pain at six months. Combined anesthesia was associated with a decrease of "medium" pain scores at six months. Of the three groups, only those in neuraxial group showed a decrease in level of pain interference in "walking ability". TKA, "worst" pain preoperatively and general were predictors of pain development at six months.

CONCLUSIONS

Patients with gonarthrosis and severe pain preoperatively may benefit from individualized pre- and intraoperative care, particularly preoperative analgesia and neuraxial anesthesia.

Chronic post-thyroidectomy pain: Incidence, typology, and risk factors

Chronic postoperative pain exists in varying degrees for every type of surgery. An evaluation of the incidence, the typology and predictive factors of chronic pain was carried out at 3 and 6months after thyroidectomy. A prospective observational study, having included each of the patients prior to their thyroidectomy, was carried out over 12months. The patients used an 11-point numerical rating scale (NRS), a neuropathic pain screening questionnaire (DN4), an evaluation scale for anxiety and for the need for information related to anaesthesia and surgery (APAIS), a questionnaire describing pain (QDSA) and a questionnaire evaluating neuropathic pain (NPSI) before surgery and at three and six months later. Three hundred and four patients were included. The questionnaires were completed by 251 patients (57 males and 194 females) at 3 and 6months (82%). At 3months, 31 out of 251 (12%) patients mentioned a DN4≥3; at 6months, this rate dropped to 23 out of 251 (9%). The average intensity of chronic postoperative pain remained low to moderate. Levels of anxiety and the need for information were higher in patients with postoperative pain at 3 and 6months. In contrast, the number of intraoperative procedures using a bilateral superficial cervical plexus block (BSCPB) was lower in patients with DN4≥3. Multivariate analysis demonstrated that the type of anaesthesia procedure interfered with the risk of delayed pain after thyroidectomy. The presence of a DN4≥3 was nearly three-fold greater in patients without BSCPB (OR 2.647, CI=1.198-5.848).

Thoracic paravertebral block reduced the incidence of chronic postoperative pain for more than 1 year after breast cancer surgery

Background

Thoracic paravertebral block (TPVB) is used to reduce pain after breast cancer surgery (BCS), but the pain-reduction effects more than 1 year after surgery are unclear.

Findings

Fifty-one patients underwent BCS at the Niigata City General Hospital from December 2009 through March 2010. To evaluate the long-term effects of TPVB in the reduction of chronic pain after BCS, we retrospectively reviewed the anesthesia charts and medical records of these patients and conducted telephone surveys regarding postoperative pain 13–17 months after surgery in 46 of these patients. Among the 46 patients enrolled in this study, 17 experienced chronic pain. There was a significant difference in the percentage of patients that received TPVB among those with and without chronic pain (patients with chronic pain 5/17 (29.4 %), patients without chronic pain 18/29 (62.1 %), p = 0.039). The pain score 3–6 h after surgery was significantly higher in the patients with chronic pain than without (p = 0.016). Bivariate logistic regression revealed that TPVB and pain score 3–6 h after surgery were independent predictive factors of chronic pain after BCS.

Conclusions

These results indicate that TPVB has the potential to reduce chronic pain for more than 1 year after BCS.

Chronic pain 1 year after foot surgery: Epidemiology and associated factors

BACKGROUND

Most studies of chronic postoperative pain focussed on major surgical procedures. Chronic postoperative pain occurred in 10% to 50% of patients and exhibited neuropathic features in 5% to 68% of cases. The objectives of this prospective single-centre study were to determine the rates of occurrence and associated factors of any chronic pain and of neuropathic chronic pain 1 year after orthopaedic surgery on the foot.

METHODS

We included consecutive patients who underwent scheduled orthopaedic surgery on the foot or ankle at a university hospital centre between 2009 and 2011. All patients received a multimodal analgesia regimen that usually combined a continuous popliteal sciatic nerve block, paracetamol, and ketoprofen, with additional ketamine if deemed appropriate. A telephone interview was conducted 1 year after the surgical procedure. The main outcome measures were moderate-to-severe pain (numerical rating scale score>3/10) 1 year after surgery at rest and during walking, and presence of neuropathic pain (defined using the DN2 score). Multivariate analysis was performed to look for associations of various perioperative clinical variables with pain.

RESULTS

One year after surgery, 55 of 260 (21%) patients reported moderate-to-severe pain at rest, 111 (43%) moderate-to-severe pain during walking, and 9 (3%) neuropathic pain. By multivariate analysis, factors independently associated with moderate-to-severe pain at rest and/or during walking 1 year after surgery were moderate-to-severe pain during the first postoperative night (P=0.048) and/or day (P=0.043) and revision surgery (P=0.001).

DISCUSSION

The rate of occurrence of moderate-to-severe pain 1 year after orthopaedic foot surgery is similar to that seen after major surgical procedures, whereas neuropathic pain seems rare. Orthopaedic surgery on the ankle or hindfoot is not more likely to be followed by chronic pain compared to surgery for hallux valgus or toe abnormalities. There is some evidence that earlier surgery might be beneficial.

LEVEL OF EVIDENCE

IV, prospective observational longitudinal cohort study.

A questionnaire study investigating the prevalence of chronic postoperative pain

BACKGROUND

Chronic postoperative pain (CPOP) is defined as pain of at least 2 months duration after a surgical procedure. Until recently, it has been a neglected topic, because it can occur after a wide spectrum of operations; however, little is known regarding its underlying mechanism, prevalence, risk factors, and treatments. We investigated characteristics of CPOP after various operations via a questionnaire.

METHODS

Patients were contacted at > 2 months after surgery, irrespective of sex, type of operation or anesthesia method, and a follow-up pain questionnaire was administered by phone.

RESULTS

One hundred forty-five of 400 patients (36.3%) described CPOP. The prevalence of CPOP was significantly lower in laparoscopic surgery (29/159, 18.2%) than open surgery (116/241, 48.1%). The prevalence of CPOP was higher with the use of PCA (patient controlled analgesia), (45.3%) than without PCA (24.6%). There were no significant differences regarding sex, anesthetic method, or duration of operation.

CONCLUSIONS

Our results indicate that the prevalence of CPOP may be related to use of an endoscope and PCA. However, it is difficult to completely explain the correlation, because this is a complex area of research. More research is needed to improve the quality of pain relief.