Timothy R. Lubenow

Validation of proposed diagnostic criteria (the “Budapest Criteria”) for Complex Regional Pain Syndrome

&NA; Current IASP diagnostic criteria for CRPS have low specificity, potentially leading to overdiagnosis. This validation study compared current IASP diagnostic criteria for CRPS to proposed new diagnostic criteria (the “Budapest Criteria”) regarding diagnostic accuracy. Structured evaluations of CRPS‐related signs and symptoms were conducted in 113 CRPS‐I and 47 non‐CRPS neuropathic pain patients. Discriminating between diagnostic groups based on presence of signs or symptoms meeting IASP criteria showed high diagnostic sensitivity (1.00), but poor specificity (0.41), replicating prior work. In comparison, the Budapest clinical criteria retained the exceptional sensitivity of the IASP criteria (0.99), but greatly improved upon the specificity (0.68). As designed, the Budapest research criteria resulted in the highest specificity (0.79), again replicating prior work. Analyses indicated that inclusion of four distinct CRPS components in the Budapest Criteria contributed to enhanced specificity. Overall, results corroborate the validity of the Budapest Criteria and suggest they improve upon existing IASP diagnostic criteria for CRPS.

An Updated Interdisciplinary Clinical Pathway for CRPS: Report of an Expert Panel

Abstract: The goal of treatment in patients with complex regional pain syndrome (CRPS) is to improve function, relieve pain, and achieve remission. Current guidelines recommend interdisciplinary management, emphasizing 3 core treatment elements: pain management, rehabilitation, and psychological therapy. Although the best therapeutic regimen or the ideal progression through these modalities has not yet been established, increasing evidence suggests that some cases are refractory to conservative measures and require flexible application of the various treatments as well as earlier consideration of interventions such as spinal cord stimulation (SCS). While existing treatment guidelines have attempted to address the comprehensive management of CRPS, all fail to provide guidance for contingent management in response to a sudden change in the patients medical status. This paper reviews the current pathophysiology as it is known, reviews the purported treatments, and provides a modified clinical pathway (guideline) that attempts to expand the scope of previous guidelines.

Inadvertent Subdural Injection: A Complication of an Epidural Block

Twenty-one hundred eighty two consecutive lumbar epidural injections were studied to determine the incidence of inadvertent subdural block retrospectively. A subdural block is defined as an extensive neural block in the absence of subarachnoid puncture, that is out of proportion to theamount of local anesthetic injected. Subdural injection is a complicationof epidural block that probably occurs more frequently than previously recognized. An earlier report has estimated the incidence of subdural blockto be 0.1%. This study, however, reports an incidence of 0.82% from a sample size of 2182 patients. Cadaveric dissection was also performed, further clarifying the presence and anatomic position of the subdural space.

Validation of Thermography in the diagnosis of reflex sympathetic dystrophy

OBJECTIVES To examine the validity of several thermogram-derived indices of autonomic functioning in the diagnosis of reflex sympathetic dystrophy (RSD). DESIGN A series of chronic pain patients were classified diagnostically based on thermogram results using discriminant function analysis, and validity measures (e.g., sensitivity, specificity) were used to determine the accuracy of computerized thermographic pixel analysis in discriminating RSD from other pathology. SETTING The study was conducted at the Rush Pain Center, a multidisciplinary outpatient pain clinic. PATIENTS A series of 46 chronic pain patients referred for suspected sympathetically mediated pain. INTERVENTIONS All patients underwent computerized thermographic examination under a baseline condition after acclimating to a climate-controlled room, immediately after a cold challenge was applied to the contralateral uninvolved extremity (4 degrees C for 90 s) and 20 min after the cold challenge. OUTCOME MEASURES Temperature during the three experimental periods, degree of temperature asymmetry between affected and nonaffected limbs during the three periods, response to cold challenge, and recovery following cold challenge were measured. RESULTS Temperature asymmetry accurately discriminated between RSD and non-RSD patients, with the most accurate asymmetry measures obtained at baseline. Responses to cold challenge and actual temperature values did not discriminate between RSD and non-RSD pain patients. CONCLUSIONS Thermography can be a useful component of RSD diagnosis. In situations where sensitivity and specificity are equally important, an asymmetry cutoff of 0.6 degree C appears optimal. If specificity (i.e., accurately ruling out non-RSD cases) is more important, a cutoff of 0.8 degree C or 1.0 degree C may be considered as well.

Psychological differences between reflex sympathetic dystrophy and non-RSD chronic pain patients

&NA; This study examined possible psychological differences between Reflex Sympathetic Dystrophy (RSD) and non‐RSD chronic pain patients. Unlike the few previous studies in this area, this study controlled statistically for age and pain duration differences across diagnostic groups, and included a non‐RSD limb pain control group. Subjects were a consecutive series of 34 RSD, 50 non‐RSD limb pain (Limb), and 165 low back pain (LBP) patients presenting for treatment at the Rush Pain Center. Analyses revealed that RSD patients reported more somatization and phobic anxiety on the Brief Symptom Inventory than LBP patients. RSD patients also reported greater coping with pain through diverting attention than LBP patients did on the Coping Strategies Questionnaire. Comparisons between the RSD and Limb groups revealed no significant differences with the exception of somatization scores. The relationship between distress and pain severity was found to be stronger in RSD and Limb patients than in LBP patients. These results provide partial support for clinical assumptions that RSD patients are more psychologically dysfunctional than other chronic pain patients. However, these conclusions do not generalize across all comparison groups. The fact that RSD and non‐RSD limb pain patients were quite similar on nearly all measures suggests that sympathetic mediation of pain is not the source of these psychological differences.

Comparison of continuous epidural infusion of fentanyl-bupivacaine and morphine-bupivacaine in management of postoperative pain

The short duration of epidural fentanyl has limited its direct comparison with epidural morphine in previous reports. The following study was performed of continuous postoperative epidural infusions at 5 ml/hr fentanyl 10 micrograms/ml (n = 59) or morphine 0.1 mg/ml (n = 48), both with bupivacaine 0.1%, in patients having cesarean sections. Postoperative evaluations included the frequency and magnitude of clinically evident respiratory depression, the adequacy of analgesia, nausea, pruritus, the ability to ambulate, and other side effects for 24 hours. Analgesia and the number of supplemental narcotic injections needed were similar in both groups. The incidence of nausea and pruritus was significantly less in the patients receiving fentanyl. No patient developed respiratory depression in either group. Patient and staff acceptance of the continuous epidural technique was excellent because there were only minor catheter-related problems associated with its use. It is concluded that continuous epidural fentanyl combined with bupivacaine offers excellent postoperative analgesia with minimal side effects.

Development of a severity score for CRPS

&NA; The clinical diagnosis of Complex Regional Pain Syndrome (CRPS) is a dichotomous (yes/no) categorization necessary for clinical decision‐making. However, such dichotomous diagnostic categories do not convey an individuals subtle and temporal gradations in severity of the condition, and have poor statistical power when used as an outcome measure in research. This study evaluated the validity and potential utility of a continuous type score to index severity of CRPS. Psychometric and medical evaluations were conducted in 114 CRPS patients and 41 non‐CRPS neuropathic pain patients. Based on the presence/absence of 17 clinically‐assessed signs and symptoms of CRPS, an overall CRPS Severity Score (CSS) was derived. The CSS discriminated well between CRPS and non‐CRPS patients (p < .001), and displayed strong associations with dichotomous CRPS diagnoses using both IASP diagnostic criteria (Eta = 0.69) and proposed revised criteria (Eta = 0.77–0.88). Higher CSS was associated with significantly higher clinical pain intensity, distress, and functional impairments, as well as greater bilateral temperature asymmetry and thermal perception abnormalities (p’s < .05). In an archival prospective dataset, increases in anxiety and depression from pre‐surgical baseline to 4 weeks post‐knee arthroplasty were found to predict significantly higher CSS at 6‐ and 12‐month follow‐up (p’s < .05). Results indicate the CSS corresponds with and complements currently accepted dichotomous diagnostic criteria for CRPS, and support its validity as an index of CRPS severity. Its utility as an outcome measure in research studies is also suggested, with potential statistical advantages over dichotomous diagnostic criteria.

Evidence-based interventional pain medicine according to clinical diagnoses. 16. Complex regional pain syndrome.

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered.

16. Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered.

Microsurgical denervation of the spermatic cord: a surgical alternative in the treatment of chronic orchialgia.

PURPOSE We demonstrated effective treatment of chronic orchialgia by microsurgical denervation of the spermatic cord. MATERIALS AND METHODS Seven men with a history of chronic orchialgia (mean duration 16.6 months) underwent this surgical procedure after conservative treatment failed. A bupivacaine spermatic cord block resulted in temporary pain relief. RESULTS There was an excellent correlation between the response to preoperative temporary cord nerve block and the surgical result. Six men had complete and permanent pain relief after surgery. One patient with bilateral orchialgia had complete unilateral relief and partial relief on the contralateral side. There was no complaint of postoperative regional hypoesthesia. CONCLUSIONS Microsurgical denervation of the spermatic cord is an effective testicular sparing surgical alternative for the treatment of chronic orchialgia.