Preoperative Multidimensional Affect and Pain Survey (MAPS) scores predict postcolectomy analgesia requirement

Role of VVZ-149, a Novel Analgesic Molecule, in the Affective Component of Pain: Results from an Exploratory Proof-of-Concept Study of Postoperative Pain following Laparoscopic and Robotic-Laparoscopic Gastrectomy

OBJECTIVE

VVZ-149 is a small molecule that both inhibits the glycine transporter type 2 and the serotonin receptor 5 hydroxytryptamine 2 A. In a randomized, parallel-group, and double-blind trial (NCT02844725), we investigated the analgesic efficacy and safety of VVZ-149 Injections, which is under clinical development as a single-use injectable product for treating moderate to severe postoperative pain.

METHODS

Sixty patients undergoing laparoscopic and robotic-laparoscopic gastrectomy were randomly assigned to receive a 10-hour intravenous infusion of VVZ-149 Injections or placebo, initiated approximately 1 hour before completion of surgical suturing. Major outcomes included pain intensity and opioid consumption via patient-controlled analgesia and rescue analgesia provided "as needed." The treatment efficacy of VVZ-149 was further examined in a subpopulation requiring early rescue medication, previously associated with the presence of high levels of preoperative negative affect in a prior Phase 2 study (NCT02489526).

RESULTS

Pain intensity was lower in the VVZ-149 (n = 30) than the placebo group (n = 29), reaching statistical significance at 4 hours post-emergence (P < .05), with a 29.5% reduction in opioid consumption for 24 hours and fewer demands for patient-controlled analgesia. In the rescued subgroup, VVZ-149 further reduced pain intensity (P < .05) with 32.6% less opioid consumption for 24 hours compared to placebo patients.

CONCLUSIONS

VVZ-149 demonstrated effective analgesia with reduced postoperative pain and opioid requirements. Consistent with the results from the previous Phase 2 study, patients with early rescue requirement had greater benefit from VVZ-149, supporting the hypothesis that VVZ-149 may alleviate the affective component of pain and mitigate excessive use of opioids postoperatively.

The effects of exergaming on pain, postural control, technology acceptance and flow experience in older people with chronic musculoskeletal pain: a randomised controlled trial

BACKGROUND

Older people with chronic musculoskeletal pain are at risk of falls. This study aimed to investigate the effects of exergaming on pain and postural control in older people with chronic musculoskeletal pain. Secondary outcomes were technology acceptance, flow experience, perceived physical exertion, expended mental effort and heart rate.

METHODS

Fifty four older adults (age: 71 ± 5 years) with chronic musculoskeletal pain were randomised into 2 groups. Group 1 received exergaming training using the Interactive Rehabilitation and Exercise System (IREX®). Group 2 undertook traditional gym-based exercise (TGB). Both groups completed twice weekly 40-min exercise sessions for 6 weeks. Perceived pain was measured using a numeric pain rating scale and the Multidimensional Affect and Pain Survey questionnaire. Postural control was measured as sway using a Kistler™ force platform. Technology acceptance was measured with the Unified Theory of Acceptance and Use of Technology questionnaire and flow experience with the Flow State Scale. Physiological measures of perceived physical exertion, expended mental effort and heart rate were recorded during all sessions.

RESULTS

The exergaming group demonstrated significant reductions in pain intensity and thermal pain including a near significant approach in physical engagement in comparison to TGB group. Although no intervention effects on postural control were found, the exergaming group showed significant improvements in three sway measures (AP SD, ML SD and AP range) over time whereas significant improvements in ML range were found in the TGB group. Relating to technology acceptance, significant intervention effects on social influence and behavioural intention were found in the TGB group instead, although both groups demonstrated increases of acceptance over time. Regarding flow experience, concentration at task was significantly influenced in the TGB group and significant increases in flow variables over time were observed in both groups. Significant increases over time in perceived physical exertion and expended mental effort were found in both groups.

CONCLUSION

Our findings support the potential of exergaming to alleviate pain and improve balance in older people with chronic musculoskeletal pain. Both forms of exercise are acceptable, intrinsically motivating and show evidence of benefit to older people with chronic musculoskeletal pain.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04029285 (retrospectively registered, July 23, 2019).

A systematic review of the risk factors for clinical response to opioids for all-age patients with cancer-related pain and presentation of the paediatric STOP pain study

BACKGROUND

Inter-patient variability in response to opioids is well known but a comprehensive definition of its pathophysiological mechanism is still lacking and, more importantly, no studies have focused on children. The STOP Pain project aimed to evaluate the risk factors that contribute to clinical response and adverse drug reactions to opioids by means of a systematic review and a clinical investigation on paediatric oncological patients.

METHODS

We conducted a systematic literature search in EMBASE and PubMed up to the 24th of November 2016 following Cochrane Handbook and PRISMA guidelines. Two independent reviewers screened titles and abstracts along with full-text papers; disagreements were resolved by discussion with two other independent reviewers. We used a data extraction form to provide details of the included studies, and conducted quality assessment using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

RESULTS

Young age, lung or gastrointestinal cancer, neuropathic or breakthrough pain and anxiety or sleep disturbance were associated to a worse response to opioid analgesia. No clear association was identified in literature regarding gender, ethnicity, weight, presence of metastases, biochemical or hematological factors. Studies in children were lacking. Between June 2011 and April 2014, the Italian STOP Pain project enrolled 87 paediatric cancer patients under treatment with opioids (morphine, codeine, oxycodone, fentanyl and tramadol).

CONCLUSIONS

Future studies on cancer pain should be designed with consideration for the highlighted factors to enhance our understanding of opioid non-response and safety. Studies in children are mandatory.

TRIAL REGISTRATION

CRD42017057740 .

Remifentanil consumption in septoplasty surgery under general anesthesia. Association with humane mu-opioid receptor gene variants

Objectives:

To evaluate the influence of the ORM1 variants in codon 118 on the intra-operative remifentanil consumption under general anesthesia.

Methods:

A prospective gene association study, performed at the Jordan University Jordan, Amman, Jordan from September 2013 to August 2014. It includes patients who underwent septoplasty surgery under general anesthesia. All patients received standard intravenous anesthesia. Anesthesia maintained with fixed dose of Sevoflurane and variable dose of Remifentanil to keep the systolic blood pressure between 90-100 mm Hg. The Remifentanil dose was calculated and correlated with ORM1 genotype variance.

Results:

Genotype and clinical data were available for 123 cases. The A118A genotype was seen in 96 patients (78%), the A118G genotype was seen in 25 patients (20.3%), and only 2 patients had genotype G118G (1.6%). The G118G variant was removed from the statistical analysis due to small sample size. There was a significant effect of ORM1 genotype variant and the amount of remifentanil consumed. The A118A genotype received 0.173 ± 0.063 µg kg^-1 min^-1 and the A118G genotype received 0.316 ± 0.100 µg kg^-1 min^-1 (p<0.0001).

Conclusion:

The ORM1 gene has a role in intra-operative remifentanil consumption in patients who underwent septoplasty surgery under general anesthesia. The A118G gene required higher dose of remifentanil compared with the A118A genotype.

Preoperative state anxiety, acute postoperative pain, and analgesic use in persons undergoing lower limb amputation

OBJECTIVES

The current study examined the relationship between preoperative anxiety and acute postoperative phantom limb pain (PLP), residual limb pain (RLP), and analgesic medication use in a sample of persons undergoing lower limb amputation.

MATERIALS AND METHODS

Participants included 69 adults admitted to a large level 1 trauma hospital for lower limb amputation. Participants' average pain and anxiety during the previous week were assessed before amputation surgery. RLP, PLP, and analgesic medication use were measured on each of the 5 days following amputation surgery.

RESULTS

Results of partial-order correlations indicated that greater preoperative anxiety was significantly associated with greater ratings of average PLP for each of the 5 days following amputation surgery, after controlling for preoperative pain ratings and daily postoperative analgesic medication use. Partial correlation values ranged from 0.30 to 0.62, indicating medium to large effects. Preoperative anxiety was also significantly associated with ratings of average RLP only on postoperative day 1, after controlling for preoperative pain ratings and daily postoperative analgesic medication use (r=0.34, P<0.05). Correlations between preoperative anxiety and daily postoperative analgesic medication dose became nonsignificant when controlling for preamputation and postamputation pain ratings.

DISCUSSION

These findings suggest that anxiety may be a risk factor for acute postamputation PLP and RLP, and indicate that further research to examine these associations is warranted. If replicated, the findings would support research to examine the extent to which modifying preoperative anxiety yields a reduction in postoperative acute PLP and RLP.

Biological inflammatory markers mediate the effect of preoperative pain-related behaviours on postoperative analgesics requirements

BACKGROUND

The predictive value of an individual's attitude towards painful situations and the status of his immune system for postoperative analgesic requirements are not well understood. These may help the clinician to anticipate individual patient's needs.

METHODS

Sixty patients, who underwent a laparoscopic cholecystectomy under standardised general anaesthesia, were included. The total analgesic requirements during the first 48 h were the primary endpoint (unitary dosage, UD). The individual's attitude towards imaginary painful situations was measured with the Situational Pain Scale (SPS). The emotional status was assessed by the Hospital Anxiety and Depression Scale (HADS) and the inflammatory status by the neutrophil-to-lymphocyte ratio (NLR).

RESULTS

Univariate analyses revealed a significant association between UD and SPS, HADS and NLR. A negative relationship between SPS and NLR (NLR = 0.820-0.180*SPS;R(2) = 0.211;P < 0.001) and a positive relationship between SPS and HADS (HADS = 14.8 + 1.63*SPS; R(2) = 0.159;P = 0.002) were observed. A multiple linear regression analysis showed that the contribution of NLR to the UD was the most effective. A mediation analysis showed a complete mediation of the effect of SPS on UD (R(2) = 0.103;P = 0.012), by the NLR (SPS on NLR: R(2) = 0.211;P = <0.001), the HADS (SPS on HADS: R(2) = 0.159;P = 0.002). The variance in UD explained by the SPS was indirect and amounts to 46% through NLR and to 34% through HADS.

CONCLUSIONS

In this series, preoperative pain-related attitudes (SPS) were associated with the postoperative analgesic requirements (UD) after a cholecystectomy. Eighty per cent of this effect was mediated by the HADS and the NLR.

Methylprednisolone injections for the treatment of Morton neuroma: a patient-blinded randomized trial

BACKGROUND

Morton neuroma is a common cause of neuralgia affecting the web spaces of the toes. Corticosteroid injections are commonly administered as a first-line therapy, but the evidence for their effectiveness is weak. Our primary research aim was to determine whether corticosteroid injection is an effective treatment for Morton neuroma compared with an anesthetic injection as a placebo control.

METHODS

We performed a pragmatic, patient-blinded randomized trial set within hospital orthopaedic outpatient clinics in Edinburgh, United Kingdom. One hundred and thirty-one participants with Morton neuroma (mean age, fifty-three years; 111 [85%] female) were randomized to receive either corticosteroid and anesthetic (1 mL methylprednisolone [40 mg] and 1 mL 2% lignocaine) or anesthetic alone (2 mL 1% lignocaine). An ultrasonographic image was obtained before treatment, and injections were performed with the needle placed under ultrasonographic guidance. The primary outcome was the difference in patient global assessment of foot health between the two groups at three months after injection. This was measured with use of a 100-unit visual analog scale (VAS) anchored by "best imaginable health state" and "worst imaginable health state."

RESULTS

Compared with the control group, global assessment of foot health in the corticosteroid group was significantly better at three months (mean difference, 14.1 scale points [95% confidence interval, 5.5 to 22.8 points]; p = 0.002). The difference between the groups was also significant at one month. Significant and nonsignificant improvements associated with the corticosteroid injection were observed for measures of pain, function, and patient global assessment of general health at one and three months after injection. The size of the neuroma as determined by ultrasonography did not significantly influence the treatment effect.

CONCLUSIONS

Corticosteroid injections for Morton neuroma can be of symptomatic benefit for at least three months.

Is there physician bias against eliciting affective qualities of pain?

GOALS

The purpose of this study is to determine the weight given to each of 3 pain dimensions by physicians who assess patients' pain experiences.

BACKGROUND

Pain is a subjective experience that has profound impact on the quality of life. The 101-Multidimensional Affect and Pain Survey (101-MAPS) is currently the only available instrument that takes into account all 3 validated dimensions of pain by classifying 101 items into "superclusters" of sensory pain, suffering, and well-being.

STUDY

Fourteen gastroenterologists, 11 internists, and 11 medicine residents from 2 teaching hospitals rated the items on the 101-MAPS based on their perception of the items' relevance to pain in gastrointestinal diseases, on a scale of 0 (least relevant) to 5 (most relevant).

RESULTS

Of the 101 items in the MAPS rated by gastroenterologists, 25 items received a median rating of 4 or above. Of these, 23 were selected from the 57 items in the sensory pain supercluster (40%) and only 1 item each from the 26 in the suffering (3.8%), and the 18 in the well-being (5.5%) dimensions. These proportions were significantly lower for the suffering (P<0.01) and well-being (P<0.05) superclusters than for the sensory pain dimension.

CONCLUSIONS

These findings suggest a bias among physicians toward sensory and against affective qualities when eliciting patients' pain experiences. The results also suggest that this bias is found as early as residency training and persists among specialists.

["Fast track" colorectal surgery]

Many factors have effect on the enhanced recovery after colon surgery. Not only the technical skill but the perioperative events needed to be optimized by the pre- and postoperative issues. Articles were obtained with search for keywords in Medline electronic database and evidences have been ranked according to the recommendation of the Oxford Evidence-Based Medicine Centre. Multicentric, randomised studies have proved that preoperative bowel emptying could not decrease the number of anastomotic insufficiency and wound infection rate; the use of abdominal drains is not necessary in every case; the proper, early oral intake is safe and well tolerated in colo-rectal surgery, and with laparoscopic surgery the same results can be achieved as with open ones. The evidences found even are not used completely. The advantage of laparoscopic surgery can be improved with fast track methods. To use correctly the affecting factors it is essential to know the current literature.

Using Pain Quality Assessment Measures for Selecting Analgesic Agents

Although those in the field of pain management have long recognized the multidimensional character of pain, global pain intensity remains the most frequently assessed domain measured in clinical trials of pain treatments. However, a number of specific pain qualities have been shown to be associated with neuropathic versus nociceptive pain and, as such, can be used for diagnostic purposes. In addition, preliminary evidence suggests that pain quality measures may be helpful for measuring outcomes in clinical trials. A number of such measures are currently available, each with its strengths and weaknesses. These measures are reviewed, and potential future uses of these tools are discussed.

Presurgery distress and specific response expectancies predict postsurgery outcomes in surgery patients confronting breast cancer

Prior to scheduled surgery, patients frequently experience particularly high levels of distress and expect a variety of postsurgery symptoms. Surgery patients who confront breast cancer are no exception. It has been suggested that such presurgery distress and response expectancies are predictive of postsurgery outcomes. To test the contribution of presurgery distress and expectancies to common postsurgery symptom outcomes (pain, nausea, fatigue, and discomfort), 63 female patients undergoing breast cancer surgery were recruited to a prospective study. Results indicated that presurgery distress uniquely contributed to patients' postsurgery nausea, fatigue, and discomfort; specific expectancies uniquely contributed to pain intensity, pain unpleasantness, and fatigue (ps < .05). Consistent with expectancy theory, associations between response expectancies and postsurgery outcomes were not due to presurgery distress.

What do ratings on unidimensional pain and emotion scales really mean? A Multidimensional Affect and Pain Survey (MAPS) analysis of cancer patient responses

The purpose of the study was to determine what dimensions of pain predicted scores on numerical rating scales (NRSs) of Pain, Anxiety, Depression, and Health Expectation in cancer patients. Seventy-one patients with intra-abdominal cancer responded to the Multidimensional Affect and Pain Survey (MAPS) and rated their pain and emotion on the NRSs. Scores on the Pain NRS were predicted by 41% of clusters in the MAPS Somatosensory Pain Supercluster, but by 100% of clusters in the Emotional Pain Supercluster, and negatively by 51% of clusters in the Well-Being Supercluster. The Anxiety and Depression NRSs were each predicted by only the Intense Pain cluster in the Somatosensory Pain Supercluster, but by all of clusters in the Emotional Pain Supercluster. The findings indicate that cancer patients' emotional state is a strong co-determinant of their sensory pain ratings. Negative emotional aspects of pain contribute also to scores on the Anxiety, Depression and Health Expectation NRSs.

Factor analysis validates the cluster structure of the dendrogram underlying the Multidimensional Affect and Pain Survey (MAPS) and challenges the a priori classification of the descriptors in the McGill Pain Questionnaire (MPQ)

The purpose of this study was to validate the content and structure of the Multidimensional Affect and Pain Survey (MAPS) by means of factor analysis. The 101-MAPS is based on a dendrogram obtained by cluster analysis and contains 30 clusters subsumed within three superclusters. If the MAPS is a valid questionnaire for the quantification of emotion and pain in patients, then factor analysis of patients' intensity ratings should produce factors which correspond to the cluster structure of the dendrogram. To confirm the structure of the dendrogram and hence, MAPS, factor analysis was applied to the responses by 100 outpatients diagnosed with early stage cancer. Principal components analysis of responses to the MAPS yielded six factors. In accordance with the hypothesis, 13 of the 17 clusters within the MAPS somatosensory pain supercluster loaded on three sensory factors: factor 1, severe sensory pain; factor 3, moderate sensory pain; and factor 6, numb/cold. Five of the eight clusters within the emotional pain supercluster loaded on factor 2, negative emotions. Four of the five clusters in the well-being supercluster loaded on factor 4, good health. Factor 5, manageable illness was loaded on by clusters from the well-being supercluster and the somatosensory pain supercluster. The homogeneity of the six factors found demonstrate the validity of the MAPS and the cluster structure of the dendrogram. MAPS proved sensitive to sex differences; women endorsed the negative emotions factor more strongly than did men. The MAPS factors were much more homogeneous than those reported in the literature for the McGill Pain Questionnaire.

Factors affecting intravenous analgesic requirements after colectomy

BACKGROUND

The purpose of this study was to determine factors that influence postoperative IV analgesic use after colectomy.

STUDY DESIGN

We retrospectively evaluated patients who underwent colectomy between January 1997 and December 2000 at our medical center and calculated the amount of postoperative IV narcotics needed in morphine equivalents. Statistical differences (p < 0.05 considered significant) were measured using the Wilcoxon rank-sum test. Correlations were performed using Spearman correlation coefficients, and linear regression analysis was also performed.

RESULTS

Four hundred eighty-one patients (235 men, 246 women) underwent colectomy; patients had a mean age of 60.6 years (range, 17 to 96 years). Procedures performed included total/subtotal colectomy (10%, n = 49), right colectomy (42%, n = 200), transverse colectomy (3%, n = 12), left/sigmoid colectomy (40%, n = 195), and low anterior resection (4%, n = 17). Laparoscopic colectomy was performed in 53 (11%) patients. Mean postoperative morphine equivalent use was 160.2 mg. Narcotic analgesic use was significantly less for women (p = 0.02), diagnosis of cancer (p = 0.02), and laparoscopic colectomy (p = 0.0001). Patients undergoing a right colectomy required less postoperative narcotics than patients having other types of colectomies (p < 0.02). There was a positive correlation between postoperative narcotic use and operative time (r = 0.14, p = 0.007) and a negative correlation with patient age (r = -0.37, p = 0.0001). Linear regression analysis demonstrated that age (p = 0.0001), female gender (p = 0.04), and laparoscopy (p = 0.001) were independent predictors for decreased narcotic use.

CONCLUSIONS

Postoperative IV narcotic analgesic use is affected by gender, patient age, indication for colectomy, operative time, type of procedure, and operative technique.

Sources of anticipatory distress among breast surgery patients

Surgical consultation concerning the possibility of breast cancer is a distressing experience, and having to take the next step of breast surgery even more so for many women. However, the sources of variability in such presurgical distress are not well understood. Sixty-one women (mean age = 51) were recruited immediately following surgical consultation in which a recommendation of breast surgery (excisional biopsy/lumpectomy) was made. Patients completed measures of distress, worry about cancer and surgery, trait anxiety, optimism and pessimism prior to surgery. Surprisingly, results revealed no effect of surgeon-provided information concerning preliminary diagnosis on patient distress. Rather, worry about what the surgeon might find concerning the breast mass during surgery, worry about having to go through the operative procedures, and patient optimism were the only factors that uniquely contributed to patient distress (p's < 0.05). This study provides a foundation for future clinical interventions to reduce presurgery distress.

Effects of adjunctive Swedish massage and vibration therapy on short-term postoperative outcomes: a randomized, controlled trial

OBJECTIVE

To examine the effects of adjunctive postoperative massage and vibration therapy on short-term postsurgical pain, negative affect, and physiologic stress reactivity.

DESIGN

Prospective, randomized controlled trial. The treatment groups were: (1) usual postoperative care (UC); (2) UC plus massage therapy; or (3) UC plus vibration therapy.

SETTING

The University of Virginia Hospital Surgical Units, Gynecology-Oncology Clinic, and General Clinical Research Center.

SUBJECTS

One hundred and five (N = 105) women who underwent an abdominal laparotomy for removal of suspected cancerous lesions.

INTERVENTIONS

All patients received UC with analgesic medication. Additionally, the massage group received standardized 45-minute sessions of gentle Swedish massage on the 3 consecutive evenings after surgery and the vibration group received 20-minute sessions of inaudible vibration therapy (physiotones) on the 3 consecutive evenings after surgery, as well as additional sessions as desired.

OUTCOME MEASURES

Sensory pain, affective pain, anxiety, distress, analgesic use, systolic blood pressure, 24-hour urine free cortisol, number of postoperative complications, and days of hospitalization.

RESULTS

On the day of surgery, massage was more effective than UC for affective (p = 0.0244) and sensory pain (p = 0.0428), and better than vibration for affective pain (p = 0.0015). On postoperative day 2, massage was more effective than UC for distress (p = 0.0085), and better than vibration for sensory pain (p = 0.0085). Vibration was also more effective than UC for sensory pain (p = 0.0090) and distress (p = .0090). However, after controlling for multiple comparisons and multiple outcomes, no significant differences were found.

CONCLUSIONS

Gentle Swedish massage applied postoperatively may have minor effects on short-term sensory pain, affective pain, and distress among women undergoing an abdominal laparotomy for removal of suspected malignant tissues.

Anger and pain sensitivity in chronic low back pain patients and pain-free controls: the role of endogenous opioids

The experience of anger (i.e. trait anger) and anger management style (i.e. anger-in, anger-out) are related to sensitivity to acute and chronic pain stimuli, although underlying mechanisms are unknown. This study tested whether anger variables are associated with impaired endogenous opioid antinociceptive activity, and whether these relationships differed between chronic pain patients and healthy normals. Forty-three chronic low back pain (LBP) sufferers and 45 pain-free normals received opioid blockade (8 mg naloxone i.v.) or placebo blockade (saline) in randomized, counterbalanced order in separate sessions. During each session, subjects participated in a 1-min finger pressure pain task followed by an ischemic forearm pain task (maximum duration 5 min), providing pain intensity ratings during and immediately following each task. As a measure of opioid antinociceptive function, drug effects were derived by subtracting placebo from blockade condition pain ratings. Multivariate general linear model analyses indicated that anger-out, but not anger-in, had significant main effects on both finger pressure drug effects (P < 0.05) and ischemic task drug effects (P < 0.05). As hypothesized, high anger-out scores were associated with an absence of opioid analgesia during the acute pain tasks; low anger-out scores were associated with effective opioid analgesia. A similar non-significant trend was noted for trait anger on finger pressure drug effects (P < 0.06). Anger-out x LBP/normal interactions were non-significant, suggesting that links between anger-out and drug effects were similar for patients and normals. Controlling for depression did not eliminate the significant relationship between anger-out and drug effects. Findings suggest that anger-in and anger-out affect pain sensitivity through different mechanisms: only the effects of anger-out may be mediated by endogenous opioid dysfunction.

Unidimensional pain rating scales: a multidimensional affect and pain survey (MAPS) analysis of what they really measure

Pain is now regarded as 'the fifth vital sign' and patients are frequently asked to score the intensity of their pain on a numerical pain rating scale (NPRS). However, the use of a unidimensional scale is questionable in view of the belief, overwhelmingly supported by clinical experience as well as by empirical evidence from multidimensional scaling and other sources, that pain has at least two dimensions: somatosensory qualities and affect. We used a Chinese translation of the 101 descriptor multidimensional affect and pain survey (MAPS) questionnaire to determine the relative contributions of various dimensions of postoperative pain to a patient's score on a unidimensional NPRS. MAPS and NPRS were administered postoperatively to 69 patients with descending colon carcinoma who were recovering from left hemi-colectomy. Multiple linear regression revealed that the emotional pain qualities supercluster (P=0.0005) and four of its eight subclusters, anxiety, depressed mood, fear and anger, significantly (P=0.001-0.007) predicted a patient's score on the unidimensional NPRS. Notably, none of the 17 subclusters in the somatosensory pain qualities supercluster predicted NPRS scores. It may be concluded that patient scores on unidimensional pain intensity scales reflect the emotional qualities of pain much more than its sensory intensity or other qualities. Accordingly such scales are poor indicators of analgesic requirement. The results also suggest that patients' postoperative anxiety and depression are inadequately treated. Based on our findings we present six unidimensional scales that should yield a more accurate assessment of the sources of a patient's pain.