Association between quantitative sensory testing, treatment choice, and subsequent pain reduction in vulvar vestibulitis syndrome

Surgical Treatment for Provoked Vulvodynia: A Systematic Review

OBJECTIVE

Provoked vulvodynia (PV), characterized by vulvar pain upon touch or pressure, is the leading cause of pain during sexual intercourse. It causes a significant decline in overall quality of life, including sexual dysfunction and mental distress. Surgical interventions, such as perineoplasty and vestibulectomy, are considered a last resort for PV cases unresponsive to less invasive therapies. This systematic review evaluates the efficacy of surgery for PV and suggests areas for future research.

MATERIALS AND METHODS

The literature search encompassed PubMed, Scopus, Web of Science, and Cochrane Library, identifying relevant peer-reviewed studies up to August 21, 2023.

RESULTS

Out of 1102 records retrieved, 29 met the eligibility criteria. Surgery was typically considered after failed conservative treatments. In 15 of the 29 studies defining surgical success as a significant reduction in dyspareunia, success rates ranged from 52% to 93%. Six studies using validated scales for pain assessment noted a significant reduction in vulvar pain following surgery (p < .001). Two studies reported enhancements in sexual function ranging from 57% to 87%, while 3 studies found 89%-97% of women regained the ability to engage in sexual intercourse after surgery. Patient satisfaction rates ranged from 79% to 93%. Bartholin cysts occurred in up to 9% of cases, the most common complication reported.

CONCLUSION

Surgery seems to be an effective and safe PV treatment option with success rates ranging from 52% to 97%, depending on the variation of outcome measures. Randomized clinical trials with established outcome measures are needed to determine the best surgical approach with minimal operative risk and optimal long-term outcomes.

Temporal Summation but Not Expectations of Pain Relief Predict Response to Acupuncture Treatment in Fibromyalgia

Fibromyalgia (FM) is a common chronic pain condition for which acupuncture treatment is increasingly utilized. However, there is no universally accepted measure to predict whether a specific patient will benefit from acupuncture. This is a single-center, single-blind, sham-controlled, randomized, noncrossover, longitudinal trial of 76 subjects with FM, assigned to either electroacupuncture (EA) or a placebo control, mock laser (ML) acupuncture. Outcome measures included clinical pain severity (Brief Pain Inventory [BPI]), degree of nociplastic pain (Fibromyalgia Survey Questionnaire), and pressure pain tolerance (PPtol). Baseline measures of temporal summation of pain and expectations for treatment relief were used as predictors. Individuals in both treatment groups experienced significant reductions in BPI (EA: P < .001, ML: P = .018) and Fibromyalgia Survey Questionnaire (EA: P = .032, ML: P = .002) after treatment; however, neither group showed a significant increase in PPtol. Lower temporal summation at baseline was correlated with greater post-treatment improvement in BPI in the EA group (rho = .389, P = .025) but not in the ML group (rho = -.272, P = .109). Lower-baseline temporal summation was correlated with greater decreases in PPtol following EA (rho = .400, P = .040), whereas the opposite was seen for ML (rho = -.562, P = .001). Treatment expectancy at baseline was not correlated with any outcome after EA or ML treatments. Our results support using a quantitative sensory testing metric, temporal summation of pain, but not expectations, to predict analgesia following acupuncture treatment for pain. PERSPECTIVE: A randomized study of acupuncture in FM found baseline temporal summation, but not expectations of pain relief, to be predictive of treatment response. CLINICAL TRIAL REGISTRATION: Registered under ClinicalTrials.gov identifier NCT02064296.

We need to talk: The urgent conversation on chronic pain, mental health, prescribing patterns and the opioid crisis

The opioid crisis’ pathways from first exposure onwards to eventual illnesses and fatalities are multiple, intertwined and difficult to dissect. Here, we offer a multidisciplinary appraisal of the relationships among mental health, chronic pain, prescribing patterns worldwide and the opioid crisis. Because the opioid crisis’ toll is especially harsh on young people, emphasis is given on data regarding the younger strata of the population. Because analgesic opioid prescription constitute a recognised entry point towards misuse, opioid use disorder, and ultimately overdose, prescribing patterns across different countries are examined as a modifiable hazard factor along these pathways of risk. Psychiatrists are called to play a more compelling role in this urgent conversation, as they are uniquely placed to provide synthesis and lead action among the different fields of knowledge and care that lie at the crossroads of the opioid crisis. Psychiatrists are also ideally positioned to gauge and disseminate the foundations for diagnosis and clinical management of mental conditions associated with chronic pain, including the identification of hazardous and protective factors. It is our hope to spark more interdisciplinary exchanges and encourage psychiatrists worldwide to become leaders in an urgent conversation with interlocutors from the clinical and basic sciences, policy makers and stakeholders including clients and their families.

Validation and Cross-Cultural Adaptation of the Spanish Version of the Pain Sensitivity Questionnaire (PSQ-S)

Experimental pain testing requires specific equipment and may be uncomfortable for patients. The Pain Sensitivity Questionnaire (PSQ) was developed to assess pain sensitivity, based on the pain intensity ratings (range: 0–10) of painful situations that occur in daily life. The main objective of this study was to carry out a cross-cultural adaptation and validation of the Spanish version of the PSQ (PSQ-S). A total of 354 subjects (296 healthy and 58 chronic pain patients) filled in the PSQ-S. A subgroup of 116 subjects performed experimental pain testing, including two modalities (cold and pressure), with different measures: pain intensity rating, pressure pain threshold, and tolerance. The validation results showed two factors: PSQ-S-moderate and PSQ-S-minor and, for the total scale and the two factors, an excellent internal consistency (Cronbach’s alpha coefficient > 0.9) and a substantial reliability (Intraclass Correlation Coefficient > 0.8). We obtained strong correlations with all the experimental pain rating parameters, catastrophizing, and depression variables, as well as moderate correlations with anxiety, central sensibilization, and impact on the quality of life. Chronic pain patients received elevated PSQ-S scores compared to healthy controls, and three cut-off values (PSQ-S-total = 7.00, PSQ-S-moderate = 7.57, and PSQ-S-minor = 6.29) based on ROC curve analyses were shown to be able to discriminate between healthy adults and adults with chronic pain. Therefore, PSQ-S may be a simple alternative to experimental pain procedures for clinical and experimental pain research.

Validation of the Turkish version of the Pain Sensitivity Questionnaire in patients with chronic pain

Objective

The Pain Sensitivity Questionnaire (PSQ) is a clinically beneficial instrument that has been proven to be correlated with various experimental pain sensitivity assessments in healthy people and in patients with chronic pain. In this study, we aimed to translate the PSQ into Turkish (PSQ-T) and validate it for the measurement of pain sensitivity among Turkish people.

Methods

Seventy-three patients with chronic back pain who were planning to undergo an interventional procedure completed the Brief Pain Inventory-Short Form (BPI-SF), Beck Depression Inventory (BDI), Beck Anxiety Inventory, Pain Catastrophizing Scale, and PSQ prior to their procedure. Subcutaneous infiltration of lidocaine was used as a standardized experimental pain stimulus. Pain was evaluated using a visual analog scale (VAS 1: infiltration in the hand, and VAS 2: infiltration in the procedure area)

Results

Scores on the PSQ-T were significantly correlated with those on the BPI-SF. A significant positive relationship was observed between VAS 1 and VAS 2 values and the PSQ-T score, BPI pain score, and BPI interference score.

Conclusions

The PSQ-T can be used as a valid and reliable tool for the assessment of pain sensitivity in the Turkish population.

Are all pain tolerance tasks the same? Convergent validity of four behavioral pain tolerance tasks, self-reported capability for suicide, and lifetime self-injurious behaviors

OBJECTIVES

Discrepancies persist regarding the extent to which different pain measures provide similar information and relate to capability for suicide and self-injurious behaviors. This study examined pain threshold, tolerance, and persistence across four modalities (cold, heat, pressure, shock) and assessed associations with self-reported capability for suicide, non-suicidal self-injury (NSSI), and suicide attempts.

METHODS

A sample of 211 students who reported lifetime suicidal ideation completed four behavioral pain tasks and self-reported on capability for suicide, NSSI, and self-injurious behaviors.

RESULTS

All pain thresholds, tolerances, and persistences were positively correlated across the four tasks. Pain facets were related to self-reported capability for suicide with small effect sizes but generally did not differ across suicide attempt or NSSI histories.

CONCLUSIONS

Pain thresholds, tolerances, and persistences demonstrated convergent validity across the four modalities, suggesting that these tasks provide similar information. Although the relation between pain and self-injurious behaviors remains unclear, these tasks can generally be used interchangeably.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for “precision medicine” or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Is Preoperative Quantitative Sensory Testing Related to Persistent Postsurgical Pain? A Systematic Literature Review

Persistent postsurgical pain (PPSP) is a common complication of surgery that significantly affects quality of life. A better understanding of which patients are likely to develop PPSP would help to identify when perioperative and postoperative pain management may require specific attention. Quantitative sensory testing (QST) of a patient's preoperative pain perception is associated with acute postoperative pain, and acute postoperative pain is a risk factor for PPSP. The direct association between preoperative QST and PPSP has not been reviewed to date. In this systematic review, we assessed the relationship of preoperative QST to PPSP. We searched databases with components related to (1) preoperative QST; (2) association testing; and (3) PPSP. Two authors reviewed all titles and abstracts for inclusion. Inclusion criteria were as follows: (1) QST performed before surgery; (2) PPSP assessed ≥3 months postoperatively; and (3) the association between QST measures and PPSP is investigated. The search retrieved 905 articles; 24 studies with 2732 subjects met inclusion criteria. Most studies (22/24) had moderate to high risk of bias in multiple quality domains. Fourteen (58%) studies reported a significant association between preoperative QST and PPSP. Preoperative temporal summation of pain (4 studies), conditioned pain modulation (3 studies), and pressure pain threshold (3 studies) showed the most frequent association with PPSP. The strength of the association between preoperative QST and PPSP varied from weak to strong. Preoperative QST is variably associated with PPSP. Measurements related to central processing of pain may be most consistently associated with PPSP.

Translation, Cross-Cultural Adaptation, and Validation of the Pain Sensitivity Questionnaire in Dutch Healthy Volunteers

An increased sensitivity to painful stimuli has been proposed to be related to the development of chronic pain. Therefore, assessment of individual pain sensitivity is useful in clinical practice. However, experimental pain testing may be uncomfortable for patients and requires specific equipment. The Pain Sensitivity Questionnaire (PSQ) has been developed to facilitate assessment of pain sensitivity. In this study, we aimed to translate and cross-culturally adapt the PSQ from its published German and English versions into the Dutch language and to assess validity of the PSQ in healthy volunteers. After translation and cross-cultural adaptation of the PSQ following international guidelines, we validated the PSQ in 394 healthy volunteers by comparing the PSQ-values with two different experimental pain tests: electrical pain tolerance (EPT) and pressure pain threshold (PPT). In addition, ratings of pain intensity during these tests were obtained on the numerical rating scale (NRS, 0-10). We found that the reliability of the PSQ based on internal consistency was good (Cronbach's alpha 0.90). PSQ-scores, adjusted for age and sex, were statistically significant and weakly inversely correlated to EPT (PSQ-moderate: rho = -0.24, p=0.007; PSQ-total: rho = -0.22, p=0.016). No statistically significant correlation between PSQ-scores and PPT was found. Concerning the pain scores, PSQ-scores were weakly to moderately correlated to EPT-NRS (PSQ-minor: rho = 0.21, p=0.021; PSQ-moderate: rho = 0.22, p=0.016; PSQ-total: rho = 0.23, p=0.009) as well as PPT-NRS (PSQ-minor: rho = 0.32, p < 0.001; PSQ-moderate: rho = 0.36, p < 0.001; PSQ-total: rho = 0.37, p < 0.001). Therefore, we concluded that the Dutch version of the PSQ is culturally appropriate for assessing self-reported pain sensitivity in healthy volunteers.

Patient-Centered Outcomes After Modified Vestibulectomy

OBJECTIVE

To describe patient outcomes after modified vestibulectomy for vulvodynia.

METHODS

This is a mixed-methods study of patients who had undergone modified vestibulectomy for vulvodynia at a tertiary care hospital from 2009 through 2016. Demographics, preoperative and postoperative examinations, symptoms, and treatments were obtained through retrospective review. Prospective semistructured interviews were conducted from 2018 through 2019 to address patient-reported changes in pain and sexual function. Qualitative analysis was performed using a grounded theory approach.

RESULTS

Twenty-two patients underwent modified vestibulectomy from 2009 through 2016. Age ranged from 22 to 65 years and mean body mass index was 24.3±5.4. The majority of patients were premenopausal (57%), sexually active (68%), and partnered (76%). Postoperatively, data on pain improvement were retrieved on 18 patients, of which 17 (94%) reported improvement. Patients used pelvic floor physical therapy, medications, and lubricants both preoperatively and postoperatively. For the qualitative analysis, thematic saturation was achieved with 14 interviews. Of 14 participants interviewed, 13 (93%) reported improvement with pain after surgery, 11 (79%) reported satisfaction with surgery, 8 (57%) reported satisfaction with sexual function, and 11 (79%) reported recommending the surgery to others. The following lead themes were identified: vulvodynia symptoms significantly affect quality of life; there is difficulty and delay in diagnosis owing to lack of information and awareness among patients and health care providers; and surgical success and satisfaction are influenced by patient perceptions with sexual dysfunction often persisting despite vulvar pain improvement.

CONCLUSION

Vulvodynia patients report improvement in pain and high overall satisfaction after modified vestibulectomy, but more variable long-term effects on sexual function.

The relationship between sensitivity to pain and conditioned pain modulation in healthy people

BACKGROUND

The relationship between sensitivity to pain and conditioned pain modulation (CPM) - a paradigm reflecting the activity of the endogenous descending analgesic system - is still unclear. This study aimed at investigating CPM magnitude in two distinct subgroups of healthy subjects, presenting low vs. high sensitivity to pain (LSP vs. HSP, respectively), by employing two different thermal paradigms of CPM.

METHOD

Ninety-five healthy subjects (out of 293 tested) were identified as LSP (n = 48) or HSP (n = 47) according to their tolerance time to noxious cold stimulation (Cold Pressor Test, 1 °C). All subjects were exposed to two different paradigms of CPM: 1) Fixed temperature 'test-pain' (TP) where phasic, fixed painful heat stimuli of 47 °C were administered before and during a prolonged 'conditioning stimulus' (cold water at 12 °C for 30 s); and 2) Individually based 'pain-60' where TP was determined as the temperature that induced pain at a magnitude of 60 on a 0-100 rating scale (with the same conditioning stimulus).

RESULT

Using both thermal paradigms, LSP subjects showed decreased CPM magnitudes in comparison to HSP (p < 0.0001 in both paradigms). Within each group, no differences in the magnitudes of CPM were found between the two paradigms.

CONCLUSION

These findings show that regardless of the thermal CPM paradigm employed, healthy individuals exhibiting low sensitivity to pain have a low pain inhibition profile and vice-versa. It is suggested that in healthy subjects, pain sensitivity predisposes the magnitude of CPM and not the other way around.

Evoked Pressure Pain Sensitivity Is Associated with Differential Analgesic Response to Verum and Sham Acupuncture in Fibromyalgia

Objective

Fibromyalgia is a chronic pain condition with few effective treatments. Many fibromyalgia patients seek acupuncture for analgesia; however, its efficacy is limited and not fully understood. This may be due to heterogeneous pathologies among participants in acupuncture clinical trials. We hypothesized that pressure pain tenderness would differentially classify treatment response to verum and sham acupuncture in fibromyalgia patients.

Design

Baseline pressure pain sensitivity at the thumbnail at baseline was used in linear mixed models as a modifier of differential treatment response to sham versus verum acupuncture. Similarly, needle-induced sensation was also analyzed to determine its differential effect of treatment on clinical pain.

Methods and Patients

A cohort of 114 fibromyalgia patients received baseline pressure pain testing and were randomized to either verum (N = 59) or sham (N = 55) acupuncture. Participants received treatments from once a week to three times a week, increasing in three-week blocks for a total of 18 treatments. Clinical pain was measured on a 101-point visual analog scale, and needle sensation was measured by questionnaire throughout the trial.

Results

Participants who had higher pain pressure thresholds had greater reduction in clinical pain following verum acupuncture while participants who had lower pain pressure thresholds showed better analgesic response to sham acupuncture. Moreover, patients with lower pressure pain thresholds had exacerbated clinical pain following verum acupuncture. Similar relationships were observed for sensitivity to acupuncture needling.

Conclusions

These findings suggest that acupuncture efficacy in fibromyalgia may be underestimated and a more personalized treatment for fibromyalgia may also be possible.

Does self-perception of sensitivity to pain correlate with actual sensitivity to experimental pain?

Background

People often state that they are “sensitive” or “insensitive” to pain. However, the accuracy and clinical relevance of such statements is unclear.

Objective

The aim of this study was to search for associations between self-perception of sensitivity to pain and experimental pain measures, including known psychophysical inhibitory or excitatory pain paradigms.

Subjects and methods

Subjective sensitivity to pain was reported by 75 healthy participants and included three self-perceived variables: pain threshold, pain sensitivity and pain intensity in response to a hypothetical painful event (hypothetical pain intensity [HPI]). Experimental pain measures consisted of thermal pain threshold (°C), suprathreshold thermal pain intensity (Visual Analog Scale, 0–100) and the psychophysical paradigms of conditioned pain modulation (CPM) and temporal summation (TS), representing inhibitory and excitatory pain processes, respectively.

Results

No significant correlations were found between self-perceived pain threshold or pain sensitivity and any of the experimental pain measures. In contrast, the reported HPI correlated with thermal pain threshold (r = −0.282; p = 0.014), suprathreshold thermal pain intensity (r = 0.367; p = 0.001) and CPM (r = 0.233; p = 0.044), but not with TS.

Conclusion

Self-perception of pain sensitivity articulated by intangible expressions such as pain threshold or pain sensitivity is unrelated to actual sensitivity to experimental pain. In contrast, when measured by intensity of a hypothetical painful event (HPI), sensitivity to pain is associated with some, but not all, experimental pain reports. Further studies are needed for better understanding of these associations and their potential clinical significance.

Validation of the Norwegian Pain Sensitivity Questionnaire

Background and purpose

There is a large variation in people’s reactions to painful stimuli. Although some conditions are more painful, the variation between people is larger than the reaction to pain across conditions. Induced experimental pain is one way to assess some aspects of these differences in pain perception. Experimental nociceptive testing is time consuming and not always feasible in a clinical setting. In order to overcome the obstacles of assessing pain sensitivity using experimental stimulation, the Pain Sensitivity Questionnaire (PSQ) was developed. The purpose of this study is to validate the Norwegian version of the PSQ.

Methods

Construct validity was examined through an exploratory principal component factor analysis with varimax rotation. Internal consistency was measured by Cronbach’s alpha reliability for subscales and the total PSQ. As confounding variables such as age and gender may contribute to the experience of pain, a regression analysis was performed with demographic variables and PSQ scores as independent variables and the experimental measures of pain as the dependent variable.

Results

The factor analysis yielded at two factor solution, with an eigenvalue greater than one, explain 58% of the variance. Cronbach’s alpha for the PSQ was 0.92. In the regression analysis, only PSQ scores contributed to explain the experimental pain intensity and tolerance. Gender only influenced the experimental pain threshold, as men had statistically significant higher heat pain threshold than women.

Conclusion

This study shows that PSQ is a valid and reliable questionnaire and might be a promising instrument for assessing pain sensitivity in Norwegian clinical settings. Further studies are needed to examine whether the PSQ can be used in clinical settings to predict postoperative pain and the development of chronic pain.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Recent advances in understanding provoked vestibulodynia

Vulvodynia refers to pain in the vulva of at least 3 months’ duration in the absence of a recognized underlying cause. Provoked, localized vestibulodynia is the term used to describe superficial pain confined to the vulvar vestibule, provoked by touch. This review will focus on provoked vestibulodynia with regard to its suggested causative factors and will discuss the role of inflammation, vulvovaginal infections, mucosal nerve fiber proliferation, hormonal associations, central pain mechanisms, pelvic floor muscle dysfunction, and genetic factors.

Clinical observations, epidemiological studies, and data from basic research emphasize the heterogeneity of vulvar pain syndromes. There is a critical need to perform prospective, longitudinal studies that will allow better diagnostic criteria and subgrouping of patients that would lead to improvements in our understanding of provoked vestibulodynia and its treatment.

Effects of a Hypnotic Induction and an Unpleasantness-Focused Analgesia Suggestion on Pain Catastrophizing to an Experimental Heat Stimulus: A Preliminary Study

Pain catastrophizing is associated with greater levels of pain. While many studies support the efficacy of hypnosis for pain, the effect on pain catastrophizing remains unclear. The present study evaluated the effect of hypnosis on pain catastrophizing using experimental heat stimulation. Twenty-two pain patients engaged in 3 conditions: baseline (no suggestion), hypnotic induction, and hypnotic induction plus analgesia suggestion. Participants with higher baseline pain showed a significant reduction in rumination following hypnotic induction plus analgesia suggestion and significant reductions in pain due to both the hypnotic induction alone and the hypnotic induction plus analgesia suggestion. The findings suggest that unpleasantness-focused hypnotic analgesia reduces pain via its effect on the rumination component of pain catastrophizing.

Experimental pain phenotyping in community-dwelling individuals with knee osteoarthritis

Pain among individuals with knee osteoarthritis (OA) is associated with significant disability in older adults, and recent evidence demonstrates enhanced experimental pain sensitivity. Although previous research showed considerable heterogeneity in the OA clinical pain presentation, less is known regarding the variability in responses to experimental pain. The present study included individuals with knee OA (n = 292) who participated in the Understanding Pain and Limitations in Osteoarthritic Disease study and completed demographic and psychological questionnaires followed by a multimodal quantitative sensory testing (QST) session. Quantitative sensory testing measures were subjected to variable reduction procedures to derive pain sensitivity index scores, which in turn were entered into a cluster analysis. Five clusters were significantly different across all pain sensitivity index variables (P < 0.001) and were characterized by: (1) low pain sensitivity to pressure pain (N = 39); (2) average pain sensitivity across most modalities (N = 88); (3) high temporal summation of punctate pain (N = 38); (4) high cold pain sensitivity (N = 80); and (5) high sensitivity to heat pain and temporal summation of heat pain (N = 41). Clusters differed significantly by race, gender, somatic reactivity, and catastrophizing (P < 0.05). Our findings support the notion that there are distinct subgroups or phenotypes based on experimental pain sensitivity in community-dwelling older adults with knee OA, expanding previous findings of similar cluster characterizations in healthy adults. Future research is needed to further understand the pathophysiological mechanisms underlying pain within these subgroups, which may be of added value in tailoring effective treatments for people with OA.

Natural history of comorbid orofacial pain among women with vestibulodynia

OBJECTIVES

We evaluated the stability of the comorbidity between vulvodynia and orofacial pain (OFP) and its associated clinical characteristics over a 2-year follow-up period.

MATERIALS AND METHODS

In an earlier study of vestibulodynia patients, we administered questionnaires assessing demographic data, self-reported pain, anxiety, somatic awareness, and presence of signs and symptoms suggestive of clinical and subclinical OFP. The present study readministered the same surveys to a subset of the original cohort after a 2-year follow-up period.

RESULTS

Of the 138 women in the previous study, 71 (51%) agreed to participate in the present study. We confirmed our earlier findings that (1) OFP is a highly prevalent (66%) condition among women with vestibulodynia, and (2) compared with women with no OFP symptoms, those with OFP symptoms experience higher levels of anxiety (P=0.005) and somatic awareness (P<0.001). Although OFP symptoms showed improvement in many of the vestibulodynia patients (33%) with OFP symptoms at baseline, 13% had either developed new symptoms or transitioned from subclinical to clinical OFP classification. Intercourse-related pain decreased in 69% of patients and increased in 24% of patients. Consistent with our earlier report, we did not observe significant differences with respect to demographics or severity of pain during intercourse among the subgroups.

DISCUSSION

OFP is a common comorbidity among women with vestibulodynia, although the presence of OFP can vary over time. The comorbidity between vestibulodynia and OFP suggests that common underlying mechanisms may mediate both conditions.

Do fibromyalgia patients benefit from cognitive restructuring and acceptance? An experimental study

BACKGROUND AND OBJECTIVES

The aim of this study was to clarify mechanisms of psychological fibromyalgia treatment by experimentally examining the effectiveness of its core elements. We assessed the effects of cognitive restructuring and acceptance on experimentally-induced heat and cold pain tolerance and pain intensity in fibromyalgia patients.

METHODS

Cold and heat pain were induced in a sample of 60 fibromyalgia patients using a thermode. We conducted ANCOVAs to examine group differences in posttest scores, co-varying for pretest scores. The between-groups factor was the type of instruction provided (acceptance, cognitive restructuring, and a control condition). In addition, we controlled for pain sensitivity, age, and depression.

RESULTS

We found that acceptance and cognitive restructuring were superior to the control condition in increasing heat pain tolerance, but did not differ from one another. With respect to cold pain tolerance, cognitive restructuring was associated with increases in cold pain tolerance compared to the control condition, while acceptance did not differ either from the control condition or from cognitive restructuring.

LIMITATIONS

Further experimental research on chronic pain treatment mechanisms is needed, particularly research on individually tailoring treatment strategies according to patients characteristics.

CONCLUSION

Results show that both, cognitive restructuring and acceptance instructions, enhance pain tolerance in fibromyalgia patients.

Psychological screening/phenotyping as predictors for spinal cord stimulation

Spinal cord stimulation (SCS) is becoming a widely used treatment for a number of pain conditions and is frequently considered as a pain management option when conservative or less invasive techniques have proven to be ineffective. Potential indications for SCS include complex regional pain syndrome (CRPS), postherpetic neuralgia, traumatic nerve injury, failed back surgery syndrome, refractory angina pectoris, peripheral vascular disease, neuropathic pain, and visceral pain (Guttman et al. Pain Pract. 9:308-11, 2009). While research on SCS is in its infancy, it is clear that substantial variation exists in the degree of benefit obtained from SCS, and the procedure does not come without risks; thus focused patient selection is becoming very important. Psychological characteristics play an important role in shaping individual differences in the pain experience and may influence responses to SCS, as well as a variety of other pain treatments (Doleys Neurosurg Focus 21:E1, 2006). In addition to psychological assessment, quantitative sensory testing (QST) procedures offer another valuable resource in forecasting who may benefit most from SCS and may also shed light on mechanisms underlying the individual characteristics promoting the effectiveness of such procedures (Eisenberg et al. Pain Pract. 6:161-165, 2006). Here, we present a brief overview of recent studies examining these factors in their relationship with SCS outcomes.

Alteration in pain modulation in women with persistent pain after lumpectomy: influence of catastrophizing

CONTEXT

Persistent pain is common after surgical treatment of breast cancer, but fairly little is known about the changes in sensory processing that accompany such pain syndromes.

OBJECTIVES

This study used quantitative sensory testing to compare psychophysical responses to standardized noxious stimulation in two groups of women who had previously undergone breast cancer surgery: women with (n=37) and without (n=34) persistent postoperative pain.

METHODS

Participants underwent a single testing session in which responses to a variety of noxious stimuli were assessed.

RESULTS

Findings suggested that women with chronic pain after breast cancer surgery display enhanced temporal summation of mechanical pain, deficits in endogenous pain inhibition, and more intense painful aftersensations compared with those without long-term pain. Some of these group differences were mediated by higher levels of pain catastrophizing in the group of women with persistent pain.

CONCLUSION

These findings suggest that persistent postoperative pain is associated with alterations in central nervous system pain-modulatory processes. Future treatment studies might benefit from targeting these pain-modulatory systems, and additional studies using functional neuroimaging methods might provide further valuable information about the pathophysiology of long-term postsurgical pain in women treated for breast cancer.

Rationale and design of a multicenter randomized clinical trial of extended release gabapentin in provoked vestibulodynia and biological correlates of response

INTRODUCTION

Few randomized controlled trials (RCTs) have been conducted to establish evidence-based management protocols for provoked vestibulodynia (PVD), a chronic vulvar pain condition affecting approximately 14 million women in the U.S. We describe the rationale and design of an NIH funded multicenter clinical trial utilizing an extended release formulation of gabapentin (G-ER), an intervention that preliminary data suggest may be efficacious for this condition.

OBJECTIVES

1) to determine if pain from tampon insertion (primary outcome measure) is lower in PVD patients when treated with G-ER compared to when treated with placebo and 2) to determine if G-ER reduces vulvar mechanical hyperalgesia, vaginal muscle pain to palpation, the number and intensity of somatic tenderpoints, spontaneous and provoked pain to intradermal capsaicin with an accompanying increase in cardiac beat-to-beat variability and to identify mechanistically-based PVD subtypes. Additional outcomes include subject reported intercourse pain and summative 24-hour pain.

METHODS

This 16-week, randomized, double-blind, placebo-controlled, crossover study will enroll 120 women 18 years and older who report tenderness localized to the vulvar vestibule, pain with tampon insertion, and, when sexually active, insertional dyspareunia. Electronically entered daily diaries will be used to determine if pain is lower in PVD subjects when treated with G-ER (up to 3000 mg/d) compared to when treated with placebo. Psychophysiological measures will be obtained at baseline and after 2 weeks at the maximum tolerated dose.

CONCLUSION

We will conduct the first multicenter RCT to confirm efficacy of an agent that is currently used in clinical practice for treating PVD.

[Update on the diagnosis and treatment of vulvodynia]

CONTEXT

Vulvodynia is a complex and multifactorial clinical condition. It is defined as chronic vulvar discomfort characterized by burning, stinging or irritation. Its diagnostic difficulty and treatment is known.

OBJECTIVES

To review the medical literature of the last 10 years from a critical point of view.

EVIDENCE ACQUISITION

A search was made in Medline/Pubmed and the Cochrane Library using the terms vulvodynia and vestibulodynia to which etiology, epidemiology, diagnosis, neurophysiological test and treatment or management, were added.

EVIDENCE SYNTHESIS

In spite of the advances achieved in all of the aspects of vulvodynia, the methodology used at present in many cases does not have the desirable statistical soundness: there are few control or placebo-controlled groups and double-blind studies. Uniformity is lacking in the scales, indexes and questionnaires for the correct evaluation of pain before and after the treatment and debatable diagnostic criteria are use. The limited use of neurophysiological diagnostic resources that validate the clinical findings has been observed in the studies analyzed. In most of the works, the medical treatments have been shown to be ineffective. Physiotherapy and cognitive-behavioral therapy seem to be promising therapeutic tools. Surgery (vestibulectomy) stands out by its demonstrated efficacy in the publications studied.

CONCLUSIONS

A multidisciplinary approach is always necessary. Topical medical, psychological and physical therapy treatments may have sum effects and become an alternative to surgery. New pathways of research and more regulated studies are required.

Validation of the pain sensitivity questionnaire in chronic pain patients

Recently, a self-rating measure for pain perception based on imagined painful daily life situations, the Pain Sensitivity Questionnaire (PSQ), has been developed and shown to correlate with experimentally obtained pain intensity ratings in healthy subjects. Here, we assessed the validity of the PSQ for investigation of general pain perception (ie, pain perception outside the site of clinical pain) in chronic pain patients. PSQ scores were obtained in 134 chronic pain patients and compared to those of 185 healthy control subjects. In a subgroup of 46 chronic pain patients, we performed experimental pain testing outside the clinical pain site, including different modalities (heat, cold, pressure, and pinprick) and different measures (pain thresholds, pain intensity ratings). Results show that PSQ scores were significantly correlated with both experimental pain intensity ratings (Pearson's r=0.71, P<.001) and experimental pain thresholds (r=-0.52, P<.001). In addition, chronic pain patients exhibited significantly elevated PSQ scores as compared to healthy controls, consistent with the generalized increase of experimentally determined pain perception that has repeatedly been reported in chronic pain patients. These results demonstrate that the PSQ constitutes a valid self-rating measure of pain perception outside the clinical pain site in chronic pain patients and might serve as an alternative to experimental assessment of pain perception outside the clinical pain site in situations where experimental pain testing is not feasible.

Elevated pain sensitivity in chronic pain patients at risk for opioid misuse

This study employed quantitative sensory testing (QST) to evaluate pain responses in chronic spinal pain patients at low risk and high risk for opioid misuse, with risk classification based on scores on the Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R). Patients were further subgrouped according to current use of prescription opioids. Of the 276 chronic pain patients tested, approximately 65% were taking opioids; a median split was used to further categorize these patients as being on lower or higher doses of opioids. The high-risk group (n = 161) reported higher levels of clinical pain, had lower pressure and thermal pain thresholds at multiple body sites, had lower heat pain tolerance, and rated repetitive mechanical stimuli as more painful relative to the low-risk group (n = 115; P's < .01). In contrast, QST measures did not differ across opioid groups. Multiple linear regression analysis suggested that indices of pain-related distress (ie, anxiety and catastrophizing about pain) were also predictive of hyperalgesia, particularly in patients taking opioids. Collectively, regardless of opioid status, the high-risk group was hyperalgesic relative to the low-risk group; future opioid treatment studies may benefit from the classification of opioid risk, and the examination of pain sensitivity and other factors that differentiate high- and low-risk groups.

PERSPECTIVE

This study demonstrates that chronic spinal pain patients at high risk for misuse of prescription opioids are more pain-sensitive than low-risk patients, whether or not they are currently taking opioids. Indices of pain-related distress were important predictors of pain sensitivity, particularly among those patients taking opioids for pain.

Optimal management of chronic cyclical pelvic pain: an evidence-based and pragmatic approach

This article reviews the literature on management of chronic cyclical pelvic pain (CCPP). Electronic resources including Medline, PubMed, CINAHL, The Cochrane Library, Current Contents, and EMBASE were searched using MeSH terms including all subheadings and keywords: "cyclical pelvic pain", "chronic pain", "dysmenorrheal", "nonmenstrual pelvic pain", and "endometriosis". There is a dearth of high-quality evidence for this common problem. Chronic pelvic pain affects 4%-25% of women of reproductive age. Dysmenorrhea of varying degree affects 60% of women. Endometriosis is the commonest pathologic cause of CCPP. Other gynecological causes are adenomyosis, uterine fibroids, and pelvic floor myalgia, although other systems disease such as irritable bowel syndrome or interstitial cystitis may be responsible. Management options range from simple to invasive, where simple medical treatment such as the combined oral contraceptive pill may be used as a first-line treatment prior to invasive management. This review outlines an approach to patients with CCPP through history, physical examination, and investigation to identify the cause(s) of the pain and its optimal management.

The DSM diagnostic criteria for dyspareunia

The DSM-IV-TR attempted to create a unitary category of dyspareunia based on the criterion of genital pain that interfered with sexual intercourse. This classificatory emphasis of interference with intercourse is reviewed and evaluated from both theoretical and empirical points of view. Neither of these points of view was found to support the notion of dyspareunia as a unitary disorder or its inclusion in the DSM-V as a sexual dysfunction. It seems highly likely that there are different syndromes of dyspareunia and that what is currently termed "superficial dyspareunia" cannot be differentiated reliably from vaginismus. It is proposed that the diagnoses of vaginismus and dyspareunia be collapsed into a single diagnostic entity called genito-pelvic pain/penetration disorder. This diagnostic category is defined according to five dimensions: percentage success of vaginal penetration; pain with vaginal penetration; fear of vaginal penetration or of genito-pelvic pain during vaginal penetration; pelvic floor muscle dysfunction; medical co-morbidity.

The ACTIV study: acupuncture treatment in provoked vestibulodynia

INTRODUCTION

Provoked vestibulodynia (PVD) is a distressing genital pain condition affecting 12% of women. Treatment modalities vary and although vestibulectomy has the highest efficacy rates, it is usually not a first-line option. Acupuncture has a long history in the traditional Chinese medicine (TCM) system and operates on the premise that pain results from the blockage or imbalance of important channels. The main principle of treatment is to move Qi and blood to cease genital pain.

AIM

To explore effect sizes and feasibility in a pilot study of acupuncture for women with PVD.

METHODS

Eight women with PVD (mean age 30 years) underwent 10 1-hour acupuncture sessions. Specific placement of the needles depended on the woman's individual TCM diagnosis. TCM practitioners made qualitative notes on participants' feedback after each session. Main Outcome Measures. Self-reported pain (investigator-developed), pain-associated cognitions (Pain Catastrophizing Scale [PCS], Pain Vigilance and Awareness Questionnaire), and sexual response (Female Sexual Function Index) were measured before and after treatment sessions 5 and 10. Qualitative analyses of TCM practitioner notes were performed along with one in-depth case report on the experience of a participant.

RESULTS

A repeated measures analysis of variance revealed significant decreases in pain with manual genital stimulation and helplessness on the PCS. An examination of effect sizes also revealed strong (though nonsignificant) effects for improved ability to have intercourse and sexual desire. Qualitative analyses were overall more positive and revealed an improvement in perceived sexual health, reduced pain, and improved mental well-being in the majority of participants.

CONCLUSIONS

Effect sizes and qualitative analyses of practitioner-initiated interviews showed overall positive effects of acupuncture, but there were statistically significant improvements only in pain with manual genital stimulation and helplessness. These findings require replication in a larger, controlled trial before any definitive conclusions on the efficacy of acupuncture for PVD can be made.

Pain sensitivity can be assessed by self-rating: Development and validation of the Pain Sensitivity Questionnaire

Experimental determination of pain sensitivity has received increasing attention because of emerging clinical applications (including prediction of postoperative pain and treatment response) and scientific implications (e.g. it has been proposed that above-average pain sensitivity is a risk factor for the development of chronic pain disorders). However, the use of experimental pain sensitivity assessment on a broad scale is hampered by its requirements on time, equipment and human resources and the fact that it is painful for the tested subject. Alternatives to experimental pain testing are currently lacking. Here we developed a self-rating instrument for the assessment of pain sensitivity, the Pain Sensitivity Questionnaire (PSQ) that is based on pain intensity ratings of daily life situations and takes 5-10min to complete. Adequate reliability of the PSQ was confirmed in 354 subjects. In a validation study comprising 47 healthy subjects, the results of comprehensive experimental pain testing, including different modalities (heat, cold, pressure, and pinprick) and different measures (pain thresholds, pain intensity ratings), were compared to the results of the PSQ. PSQ scores were significantly correlated to experimental pain intensity ratings (r = 0.56, p < 0.001) but not to pain thresholds (r = 0.03). Prediction of experimental pain intensity ratings by the PSQ was better than by pain-associated psychological factors (pain catastrophizing, depression, anxiety). This shows that the PSQ may be a simple alternative to experimental pain intensity rating procedures in healthy subjects and makes the PSQ a highly promising tool for clinical and experimental pain research.

Somatization and psychological distress among women with vulvar vestibulitis syndrome

OBJECTIVE

To investigate the distribution of psychological characteristics and pain reporting among women with vulvar vestibulitis syndrome (VVS).

METHODS

In this exploratory study, 109 women with VVS completed a battery of questionnaires to assess pain with intercourse and psychological characteristics (e.g. somatization, anxiety, distress). The distribution of these characteristics was compared, first with a conventional binary classification schema (primary and secondary) and subsequently with a 3-category schema (primary, latent primary, secondary).

RESULTS

Severity of pain with intercourse did not differ among the subgroups using either classification schema. Women with primary VVS consistently showed higher levels of somatization, anxiety, and distress compared with those with secondary VVS. Using a 3-tiered classification system, we found no difference between latent primary diagnosis and the other 2 groups (primary and secondary).

CONCLUSION

This study highlights the critical need for research on subtype definition and the role of psychological factors in VVS.

Overlap between orofacial pain and vulvar vestibulitis syndrome

OBJECTIVES

To explore the prevalence of orofacial pain (OFP) among patients with vulvar vestibulitis syndrome (VVS) and to examine the relationship between signs and symptoms of OFP and clinical characteristics of women with VVS, we investigated differences in psychologic characteristics and severity of painful intercourse.

METHODS

In this cross-sectional exploratory study, 137 women with VVS completed questionnaires that assessed levels of pain, anxiety, somatization, and presence of signs and symptoms suggestive of clinical and subclinical OFP. Demographic data were gathered from medical records.

RESULTS

OFP was found to be a highly prevalent (78%) condition among women with VVS. Compared with women who had no OFP symptoms (n=30), those with symptoms (n=64) reported higher levels of anxiety (45.0 vs. 37.8, Bonferroni adjusted P=0.017), somatization (125.2 vs. 96.0, Bonferroni adjusted P<0.001), and psychologic distress (62.8 vs. 56.0, Bonferroni adjusted P=0.002). Although we observed a similar trend among women with subclinical OFP (n=43), this trend only reached statistical significance with respect to somatization. Differences were not detected for demographics, duration of pain, and severity of pain during intercourse across the 3 groups.

DISCUSSION

OFP is a common condition among women with VVS. Because severity and duration of painful intercourse did not differ by OFP classification but psychologic characteristics did, we must begin to question a unidimensional focus on vestibular mucosa as a reason for pain and persistent distress.

Heritability of responses to painful stimuli in women: a classical twin study

There is as yet no conclusive evidence for the heritability of pain sensitivity in humans. We performed a classical twin study to evaluate the relative contributions of genetic and environmental factors on responses to painful stimuli in women. Ninety-eight pairs of twins, 51 monozygotic (MZ) and 47 dizygotic (DZ), were recruited from the TwinsUK adult registry held at St Thomas' Hospital, London. The correlation of quantitative sensory testing scores for the different responses to painful stimuli were compared between the MZ and DZ twin pairs and structural equation modelling was used to provide an estimate of the heritability. Statistically significant genetic components (varying between 22 and 55%) were seen for the responses to the majority of painful stimuli including: heat pain threshold (HPT), the pain rating during induction of a thermal burn, the secondary areas of punctate hyperalgesia and brush evoked allodynia following the induction of a 45 degrees C thermal burn, and the pain ratings during the iontophoresis of adenosine triphosphate (ATP) and acid. The area of skin flare following thermal burn induction did not have a significant genetic component; rather common environmental factors provided the greatest contribution (65%). In our experiment neither shared genetic nor environmental features were significant in determining the extent of thermal sensitisation. In summary we show that sensitivity to a variety of experimental thermal, mechanical and chemical pain-producing stimuli has a genetic contribution. Our study demonstrates the importance of genetic factors in determining human experimental pain sensitivity, and opens the way for its use as a phenotype in gene discovery. Since experimental pain sensitivity is known to be a predictor for pathological pain, our data imply that genetic factors have an important aetiological contribution towards clinical pain states.

Evidence of diffuse noxious inhibitory controls (DNIC) elicited by cold noxious stimulation in patients with provoked vestibulodynia

Provoked vestibulodynia is a common cause of superficial dyspareunia in young women. Recent evidence has pointed out the importance of studying endogenous pain modulation in these women. An impairment of diffuse noxious inhibitory controls (DNIC) has been suggested in chronic pain conditions with a female predominance such as fibromyalgia and temporomandibular disorder. Our aim was to examine whether patients with provoked vestibulodynia and healthy women with or without combined oral contraceptives (COC) display a DNIC response to cold noxious stimulation. Twenty patients with provoked vestibulodynia not using COC, 20 healthy women on COC and 20 healthy women without COC were included and tested days 7-11 of their menstrual cycle. Pressure pain thresholds (PPTs) and pain ratings using VAS were measured on the arm and leg before and during a cold pressor test. A socio-medical questionnaire, the Hospital and Anxiety Depression Scale and the Short Form-36 were completed. The majority of the subjects in all three study groups significantly increased their PPTs during cold noxious stimulation indicating a DNIC response. The patients displayed lower PPTs compared to the healthy women. Depression, anxiety and bodily pain were more often reported by the patients. No differences related to the intake of COC were observed between the healthy women. In conclusion, women with provoked vestibulodynia as well as healthy women irrespective of COC status display a DNIC response indicating an endogenous pain inhibition. However, the results imply a systemic hypersensitivity in women with vestibulodynia with low general pain thresholds as compared to healthy women.

Self-reported pain sensitivity: lack of correlation with pain threshold and tolerance

Many recent studies and several reviews have highlighted the potential clinical applications of experimental pain testing (e.g., for predicting post-surgical pain, treatment responsiveness, etc.). However, the implementation of quantitative sensory testing of pain sensitivity on a broad scale is limited by requirements of time, equipment, and expertise, and their associated costs. One reasonable question is whether one can obtain, via self-report, a valid index of an individual's pain sensitivity and pain tolerance. We analyzed data from a large number of subjects (n=505) who had undergone standardized thermal pain testing, and found that while higher self-reported pain sensitivity was associated with higher scores on a measure of anxiety, no relationship was observed between subjects' self-report of pain sensitivity and subjects' actual pain threshold or tolerance. These findings suggest that circumventing psychophysical pain testing by assessing individuals' self-reported pain sensitivity is unlikely to be a useful strategy.

Self-reported pain sensitivity: lack of correlation with pain threshold and tolerance

Many recent studies and several reviews have highlighted the potential clinical applications of experimental pain testing (e.g., for predicting post-surgical pain, treatment responsiveness, etc.). However, the implementation of quantitative sensory testing of pain sensitivity on a broad scale is limited by requirements of time, equipment, and expertise, and their associated costs. One reasonable question is whether one can obtain, via self-report, a valid index of an individual's pain sensitivity and pain tolerance. We analyzed data from a large number of subjects (n=505) who had undergone standardized thermal pain testing, and found that while higher self-reported pain sensitivity was associated with higher scores on a measure of anxiety, no relationship was observed between subjects' self-report of pain sensitivity and subjects' actual pain threshold or tolerance. These findings suggest that circumventing psychophysical pain testing by assessing individuals' self-reported pain sensitivity is unlikely to be a useful strategy.

Tender point examination in women with vulvar vestibulitis syndrome

OBJECTIVES

To examine whether generalized pain sensitivity in women with vulvar vestibulitis syndrome (VVS) is increased, suggestive of altered pain processing at the level of the central nervous system, and to investigate pain history and other pain measures in women with VVS.

METHODS

Sixteen women with VVS and 16 age-matched (+/-3 years) and oral contraceptive status-matched (yes or no) control women participated in this cross-sectional study. The TP examination, typically used in the diagnosis of FMS, consists of the palpation of 9 bilateral nonvulvar areas by a blinded rheumatologist and was the main measure of generalized sensitivity. Pain intensity and unpleasantness rating (0 to 10) were recorded after each palpation. In addition, nonvulvar pain history, pain interference, catastrophizing, and anxiety were assessed via questionnaires.

RESULTS

Women with VVS had significantly more painful TPs than nonaffected women; they reported significantly higher pain intensity and unpleasantness ratings and displayed more pain behaviors than controls (P<0.05). Furthermore, VVS patients reported having experienced more pain problems and associated interference, they catastrophized more in response to vulvar and nonvulvar pain, and they had higher levels of trait anxiety than controls (P<0.05).

DISCUSSION

These results are consistent with recent findings of generalized sensitivity and heightened responses to pain in women with VVS. These results suggest that the mechanisms involved in VVS may include those that are genital specific in addition to those that are more generalized, and possibly centrally mediated.