The incidence, impact, and risk factors for moderate to severe persistent pain after breast cancer surgery: a prospective cohort study.

BACKGROUND: Few Australasian studies have evaluated persistent pain after breast cancer surgery. OBJECTIVE: To evaluate the incidence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand cohort. DESIGN: Prospective cohort study. METHODS: Consented patients were reviewed at 3 timepoints (preoperative, 2 weeks and 6 months postoperative). Pain incidence and interference, psychological distress and upper limb disability were assessed perioperatively. Clinical, demographic, psychological, cancer treatment-related variables, quantitative sensory testing, and patient genotype (COMT, OPRM1, GCH1, ESR1, and KCNJ6) were assessed as risk factors using multiple logistic regression. RESULTS: Of the 173 patients recruited, 140 completed the 6-month follow-up. Overall, 15.0% (n = 21, 95% CI: 9.5%-22.0%) of patients reported moderate to severe persistent pain after breast cancer surgery with 42.9% (n = 9, 95% CI: 21.9%-66.0%) reporting likely neuropathic pain. Pain interference, upper limb dysfunction and psychological distress were significantly higher in patients with moderate to severe pain (P < .004). Moderate to severe preoperative pain (OR= 3.60, 95% CI: 1.13-11.44, P = .03), COMT rs6269 GA genotype (OR = 5.03, 95% CI: 1.49-17.04, P = .009) and psychological distress at postoperative day 14 (OR= 1.08, 95% CI: 1.02-1.16, P = .02) were identified as risk factors. Total intravenous anesthesia (OR= 0.31, 95% CI: 0.10 - 0.99, P = .048) was identified as protective. CONCLUSION: The incidence of moderate to severe persistent pain after breast cancer surgery is high with associated pain interference, physical disability, and psychological distress. Important modifiable risk factors were identified to reduce this important condition.

Trajectories of Pain and Function Outcomes up to 5 to 8 Years Following Total Knee Arthroplasty.

BACKGROUND: There appears to be substantial variability in outcomes > 2 years following total knee arthroplasty (TKA) that is masked by whole group analyses. The goal of the study was to identify trajectories of pain and function outcomes up to 5 to 8 years post-TKA and to identify baseline factors that are associated with different trajectories of recovery. METHODS: Baseline, 6-month, and 12-month pain and function data were collected in a previous study investigating predictors of outcome following primary TKA (n = 286), along with a variety of baseline predictor variables. The present study obtained pain and function data at 5 to 8 years following TKA in the same cohort (n = 201). Latent class linear mixed models were used to identify different classes of pain and functional trajectories over time. The extent to which differences across latent classes were explained by baseline predictor variables was determined. RESULTS: Three classes of pain and two classes of function trajectory were identified. While most patients (84% to 93%) followed a trajectory that showed an initial rapid gain following surgery that was sustained through 5 to 8 years, both pain and function included at least one trajectory class that showed a meaningful change after 12 months. No predictor variables were significantly associated with either the pain or function classes. CONCLUSIONS: Most patients follow a traditional trajectory of recovery in knee pain and function over 5 to 8 years. However, alternative trajectories are observed in an important minority of patients such that knee pain and function at 12 months after surgery does not always reflect outcomes at 5 to 8 years.

A combination of high preoperative pain and low radiological grade of arthritis is associated with a greater intensity of persistent pain 12 months after total knee arthroplasty.

AIMS: Despite new technologies for total knee arthroplasty (TKA), approximately 20% of patients are dissatisfied. A major reason for dissatisfaction and revision surgery after TKA is persistent pain. The radiological grade of osteoarthritis (OA) preoperatively has been investigated as a predictor of the outcome after TKA, with conflicting results. The aim of this study was to determine if there is a difference in the intensity of pain 12 months after TKA in relation to the preoperative radiological grade of OA alone, and the combination of the intensity of preoperative pain and radiological grade of OA. METHODS: The preoperative data of 300 patients who underwent primary TKA were collected, including clinical information (age, sex, preoperative pain), psychological variables (depression, anxiety, pain catastrophizing, anticipated pain), and quantitative sensory testing (temporal summation, pressure pain thresholds, conditioned pain modulation). The preoperative radiological severity of OA was graded according to the Kellgren-Lawrence (KL) classification. Persistent pain in the knee was recorded 12 months postoperatively. Generalized linear models explored differences in postoperative pain according to the KL grade, and combined preoperative pain and KL grade. Relative risk models explored which preoperative variables were associated with the high preoperative pain/low KL grade group. RESULTS: Pain 12 months after TKA was not associated with the preoperative KL grade alone. Significantly increased pain 12 months after TKA was found in patients with a combination of high preoperative pain and a low KL grade (p = 0.012). Patients in this group were significantly more likely to be male, younger, and have higher preoperative pain catastrophizing, higher depression, and lower anxiety (all p ≤ 0.05). CONCLUSION: Combined high preoperative pain and low radiological grade of OA, but not the radiological grade alone, was associated with a higher intensity of pain 12 months after primary TKA. This group may have a more complex cause of pain that requires additional psychological interventions in order to optimize the outcome of TKA.Cite this article: Bone Joint J 2022;104-B(11):1202-1208.

A Higher Grey Matter Density in the Amygdala and Midbrain Is Associated with Persistent Pain Following Total Knee Arthroplasty.

OBJECTIVE: The development of persistent pain following total knee arthroplasty (TKA) is common, but its underlying mechanisms are unknown. The goal of the study was to assess brain grey matter structure and its correlation with function of the nociceptive system in people with good and poor outcomes following TKA. SUBJECTS: Thirty-one people with LOW_PAIN (<3/10 on the numerical ratings scale [NRS]) at six months following TKA and 15 people with HIGH_PAIN (≥3/10 on the NRS) were recruited into the study. METHODS: Grey matter in key brain areas related to nociception was analyzed using voxel-based morphometry (VBM). Nociceptive facilitatory and inhibitory processes were evaluated using quantitative sensory testing (QST). QST scores and grey matter density in prespecified brain regions were compared between the LOW_PAIN and HIGH_PAIN groups. Regression analyses were used to analyze the associations between the grey matter and QST scores. RESULTS: There were no between-group differences in QST measures. In the VBM analysis, the HIGH_PAIN group had a higher grey matter density in the right amygdala, right nucleus accumbens, and in the periaqueductal grey (PAG), but lower grey matter density in the dorsal part of the left caudate nucleus. Grey matter density in the right amygdala and PAG correlated positively with temporal summation of pain. CONCLUSIONS: Persistent pain at six months after TKA is associated with a higher grey matter density in the regions involved in central sensitization and pain-related fear, which may contribute to the development of persistent pain after surgery.

The Prevalence, Impact, and Risk Factors for Persistent Pain After Breast Cancer Surgery in a New Zealand Population.

OBJECTIVE: Few Australasian studies have assessed persistent pain after breast cancer surgery. This study aims to evaluate the prevalence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand population. METHODS: Retrospective cross-sectional study of patients who underwent breast cancer surgery between six and 48 months previously. Validated questionnaires were used to assess pain prevalence and impact, psychological distress, and upper limb function. Patients' clinical records were assessed for potential risk factors. RESULTS: Of the 375 patients who were sent questionnaires, 201 were included in the study. More than half of the patients (N = 111, 55%) reported breast surgery related-persistent pain, with 46 (23%) rating the pain as moderate to severe. Neuropathic pain was reported by 21 (46%) patients with moderate to severe pain. Pain interference, upper limb dysfunction, and psychological distress were significantly higher in patients with moderate to severe pain (P < 0.001). Non-European ethnicity (odds ratio [OR] = 5.02, 95% confidence interval [CI] = 2.05-12.25, P < 0.001), reconstruction surgery (OR = 4.10, 95% CI = 1.30-13.00, P = 0.02), and axillary node dissection (OR = 4.33, 95% CI = 1.19-15.73, P < 0.03) were identified as risk factors for moderate to severe pain by multivariate logistic regression analysis. CONCLUSIONS: Moderate to severe persistent pain after breast cancer surgery affects many New Zealand patients, and is associated with impaired daily life activities, physical disability, and psychological distress. Large numbers of patients undergo breast cancer surgery annually. This study emphasizes the importance of identification and management of these patients perioperatively.

Post-operative mortality rates for neck of femur fracture at Waitemata District Health Board.

AIM: Mortality rates of up to 38% at one year have been reported following surgery for neck of femur fractures. The aim of this review is to evaluate the post-operative mortality rates and trends over time for patients with fractured neck of femur at Waitemata District Health Board. METHOD: A retrospective cohort study of all patients who received surgery following a neck of femur fracture at Waitemata District Health Board between 2009 and 2016. Inpatient data was retrieved from electronic hospital records and mortality rates from the Ministry of Health, New Zealand. Analyses included crude mortality rates and trends over time, and time-to-theatre from presentation with neck of femur fracture. RESULTS: A total of 2,822 patients were included in the study; mean age 81.9 years, 70.4% female and 29.6% male. Overall post-operative crude rates for inpatient, 30-day and one-year mortality were 3.7%, 7.2% and 23.8% respectively. Adjusted analyses showed a statistically significant decrease in mortality rates between 2009 and 2016 at inpatient (p=0.001), 30 days (p=<0.001) and one year (p=<0.001) time periods. There was also a significant association between time-to-theatre and mortality at inpatient (p=0.002), 30 days (p=0.0001), and one year (p=0.0002) time periods. CONCLUSION: Mortality rates following surgery for fractured NOF have significantly improved over recent years at Waitemata District Health Board. Reduced time-to-theatre is associated with decreased inpatient, 30-day and one-year mortality.

Orthostatic intolerance following hip arthroplasty: incidence, risk factors and effect on length of stay: A prospective cohort study.

BACKGROUND: Early postoperative mobilisation is important for enhanced recovery, but can be hindered by orthostatic intolerance, characterised by dizziness, nausea, vomiting, feeling of heat, blurred vision and ultimately syncope. Although the incidence of orthostatic intolerance following total hip arthroplasty has been identified, few studies have yet investigated potential risk factors for developing orthostatic intolerance after hip arthroplasty. OBJECTIVES: The aim of this study was to assess the incidence of orthostatic intolerance on the first postoperative day after total hip arthroplasty, potential predisposing risk factors for developing orthostatic intolerance and its effect on length of stay. DESIGN: A prospective observational study. SETTING: Tertiary hospital, Auckland, New Zealand, May to September 2015. PATIENTS: One hundred and seventeen consecutive patients undergoing unilateral total hip arthroplasty. Patients were excluded if they had revision surgery. MAIN OUTCOME MEASURES: Incidence of orthostatic intolerance during mobilisation on the first postoperative day. Significant peri-operative risk factors for developing orthostatic intolerance were identified using logistic regression. Length of stay was compared between orthostatic intolerant and orthostatic tolerant patients using the Mann-Whitney U-test. RESULTS: On the first postoperative day, 22% of patients failed mobilisation due to orthostatic intolerance. Factors independently associated with orthostatic intolerance were female sex; OR (95% CI), 3.11 (1.01 to 9.57), postoperative use of gabapentin; OR 3.55 (1.24 to 10.15) and high peak pain levels (≥5/10) during mobilisation; OR 4.05 (1.30 to 12.61). Overall, 78% of patients were correctly identified. The model was more accurate at predicting those who would not get orthostatic intolerance (89% correct), compared with those who did have orthostatic intolerance (39% correct). Length of stay was longer in patients with orthostatic intolerance (P = 0.019). CONCLUSION: Orthostatic intolerance is common after total hip arthroplasty. Optimising pain control prior to mobilisation and limiting gabapentin use may modify the risk of developing postoperative orthostatic intolerance. Although personalised recovery pathways appear attractive, at present, the ability to predict at-risk individuals is still limited.

Ethnic- and sex-related differences in pain characteristics, psychological distress and pain-related disability in patients attending a New Zealand teaching hospital pain service.

AIM: The aim of the present observational study was to provide a description of the demographic, psychological and pain characteristics of patients attending the Waitemata Pain Services (WPS), Auckland, New Zealand. METHOD: Data were collected via a comprehensive paper-pencil questionnaire handed out to 798 consecutive new patients seen at the WPS over a four-year period. RESULTS: 32.3% attending the WPS were men and 67.7% women, with a mean age of 52.1 years. 65.7% of patients were New Zealand Europeans, followed by 19.1% other Europeans, 5.7% Asians, 3.9% Maori, 2.8% Middle Eastern/Latin/Africans and 2.7% Pacific Islanders. Patients reported an average of 2.6 visits to the GP before presenting to the unit. Average pain duration was seven years and seven months. Women reported a significantly higher number of pain sites in the whole body, as well as in the left and right side of the body compared to men (p<0.0001 for all). Highest interference due to pain was found for enjoyment of life. Men and women further differed in a range of psycho-behavioural variables, with women reporting less psychological distress and depression but more stress compared to men (p<0.05 for all). Men showed higher levels of kinesiophobia (p<0.005) and less pain acceptance and pain willingness (p<0.05 for both). Cross-cultural comparison found Maori patients reported highest pain levels, highest number of pain sites, highest pain interference, as well as highest levels of psychological distress, depression, stress and anxiety compared to all other ethnicities. Lowest pain severity was reported for New Zealand European patients and lowest interference due to pain for Pacific Islanders. While Middle Eastern/Latin/African patients showed highest levels of kinesiophobia, Pacific Islanders had the highest tendencies to catastrophise about their pain. CONCLUSION: There are important sex- and ethnicity-related differences in the clinical presentation of chronic pain patients attending a large, hospital-based New Zealand pain service. While service provision can be based on generalised guidelines, specific interventions should be informed by important demographic and cultural variables. Studies are needed to identify strategies to improve service delivery in subgroups of the population who may be undertreated or lack access to appropriate interventions.

Pain Catastrophizing is Not Associated With Spinal Nociceptive Processing in People With Chronic Widespread Pain.

OBJECTIVES: Pain catastrophizing has been associated with higher pain intensity, increased risk of developing chronic pain and poorer outcomes after treatment. Despite this, the mechanisms by which pain catastrophizing influences pain remain poorly understood. It has been hypothesized that pain catastrophizing may impair descending inhibition of spinal level nociception. The aims of this study were to compare spinal nociceptive processing in people with chronic widespread pain and pain-free controls and examine potential relationships between measures of pain catastrophizing and spinal nociception. MATERIALS AND METHODS: Twenty-six patients with chronic widespread pain and 22 pain-free individuals participated in this study. Spinal nociception was measured using the nociceptive flexion reflex (NFR) threshold and NFR inhibition, measured as the change in NFR area during exposure to a second, painful conditioning stimulus (cold water immersion). Pain catastrophizing was assessed using the Pain Catastrophizing Scale and a situational pain catastrophizing scale. RESULTS: Compared with pain-free controls, patients with chronic widespread pain had higher pain catastrophizing scores and lower NFR thresholds. Although NFR area was reduced by a painful conditioning stimulus in controls, this was not apparent in individuals with chronic widespread pain. No significant correlations were observed between measures of pain catastrophizing and spinal nociception. DISCUSSION: Despite increased excitability and decreased inhibition of spinal nociception in patients with chronic widespread pain, we could find no evidence of a significant relationship between pain catastrophizing and measures of spinal nociceptive processing.

Low Versus Standard Urine Output Targets in Patients Undergoing Major Abdominal Surgery: A Randomized Noninferiority Trial.

OBJECTIVE: To determine whether a low perioperative minimum urine output target is safe and fluid sparing when compared with the standard target. BACKGROUND: A minimum hourly urine output of 0.5 mL/kg is a key target guiding perioperative fluid therapy. Few data support this standard practice, which may contribute to perioperative fluid overloading. METHODS: We randomized patients without significant risk factors for acute kidney injury undergoing elective colectomy to a minimum urine output target of 0.2 mL/kg/h (low group) or 0.5 mL/kg/h (standard group) from induction of anesthesia until 8 AM 2 days after surgery. Maintenance fluids were standardized and additional fluids administered to achieve the targets. Primary outcome was noninferiority for urine neutrophil gelatinase-associated lipocalin on the day after surgery. RESULTS: Between November 21, 2011 and July 11, 2013, 40 participants completed the study. The low group received 3170 mL (95% confidence interval 2380-3960) intravenous fluids versus 5490 mL (95% confidence interval 4570-6410) in the standard group (P = 0.0004), and was noninferior for neutrophil gelatinase-associated lipocalin [14.7 µg/L (interquartile range 7.60-28.9) vs 18.4 µg/L (interquartile range 8.30-21.2); Pnoninferiority = 0.0011], serum cystatin C (Pnoninferiority < 0.0001), serum creatinine (Pnoninferiority = 0.0004), and measured glomerular filtration (Pnoninferiority = 0.0003). Effective renal plasma flow increased in both groups after surgery, and more in the standard group (Pnoninferiority = 0.125). CONCLUSIONS: A perioperative urine output target of 0.2 mL/kg/h is noninferior to the standard target of 0.5 mL/kg/h and results in a large intravenous fluid sparing. This target should be adopted in surgical patients without significant kidney injury risk factors.