Acute and chronic neuropathic pain profiles after video-assisted thoracic surgery: A prospective study.

Acute postsurgical pain, probably including acute neuropathic pain (ANeP), starts at the early postoperative period, and chronic postsurgical pain including chronic neuropathic pain (CNeP) persists at least 3 months after surgery. Although it must be important for prevention and treatment of acute and chronic postoperative pain to reveal the time course of postoperative neuropathic characteristics, a neuropathic pain profile after surgery has not been evaluated.Pain status at the surgical site in adult patients who underwent video-assisted thoracic surgery (VATS) for lung cancer was prospectively assessed until 12 months after surgery. Neuropathic characteristics were assessed using the Douleur Neuropathique 4 (DN4) questionnaire until 6 days after surgery and the DN2 questionnaire throughout the study.Twenty-seven patients were enrolled in this study. Pain intensity at surgical sites were significantly higher at 1 and 6 days after surgery during resting state, and were also significantly higher at 3, 6, and 12 months after surgery during movement than those before surgery. The incidence of ANeP was 33.3% at 1 day, and 18.5% at 6 days after surgery. The incidence of CNeP decreased to 12.5% at 3 months, 5.0% at 6 months, and 0.0% at 12 months after surgery. The number of neuropathic characteristics, assessed by DN2 scores, significantly increased at 1 and 6 days after surgery, compared to those before surgery. DN2 scores at 3, 6, and 12 months after surgery, however, showed no significant differences compared to those before surgery.In patients with acute postsurgical pain, 20% to 30% of patients show ANeP characteristics, and the incidence of CNeP gradually decreases after VATS in patients with chronic postsurgical pain.

Association between neuropathic pain characteristics and DNA methylation of transient receptor potential ankyrin 1 in human peripheral blood.

Elucidation of epigenetic mechanisms correlating with neuropathic pain in humans is crucial for the prevention and treatment of this treatment-resistant pain state. In the present study, associations between neuropathic pain characteristics and DNA methylation of the transient receptor potential ankyrin 1 (TRPA1) gene were evaluated in chronic pain patients and preoperative patients. Pain and psychological states were prospectively assessed in patients who suffered chronic pain or were scheduled for thoracic surgery. Neuropathic characteristics were assessed using the Douleur Neuropathique 4 (DN4) questionnaire. DNA methylation levels of the CpG islands in the TRPA1 gene were examined using whole blood. Forty-eight adult patients were enrolled in this study. Increases in DNA methylation rates at CpG -51 showed positive correlations with increases in the DN4 score both in preoperative and chronic pain patients. Combined methylation rates at CpG -51 in these patients also significantly increased together with increase in DN4 scores. Neuropathic pain characteristics are likely associated with methylation rates at the promoter region of the TRPA1 gene in human peripheral blood.

Neuropathic Characteristics In Patients With Persistent Idiopathic Facial Pain.

BACKGROUND: Persistent idiopathic facial pain (PIFP) is a subtype of painful cranial neuropathies and other facial pains. The involvement of neuropathic mechanisms in PIFP, however, remains controversial. Using the Douleur Neuropathique 4 (DN4) questionnaire, the present study examined neuropathic characteristics in patients with PIFP. METHODS: The multi-institutional retrospective study collected the following clinical data from 205 consecutive patients with adult chronic pain: gender, age, BMI, diseases causing chronic pain, disease duration, visual analogue scale score of pain strength, and DN4 score. To compare neuropathic characteristics between PIFP and postherpetic neuralgia (PHN), we selected patients with PIFP (n=19) and patients with PHN (n=33), and performing a case-control study in which each patient with PHN or PIFP was matched by age and gender (n=16 in each group). RESULTS: DN4 score was significantly lower in the PIFP group than in the PHN group before and after matching. The incidence when DN4 was ≥4 was 10.5% before matching and 12.5% after matching in the PIFP group, both of which were significantly lower than those in the PHN group before and after matching (66.7% and 75.0%). CONCLUSION: Ten percent of the PIFP patients likely show neuropathic pain characteristics.

Reliability and validity of the Japanese translation of the DN4 Diagnostic Questionnaire in patients with neuropathic pain.

BACKGROUND: The Douleur Neuropathique 4 questionnaire (DN4) is a simple and objective tool developed by the French Neuropathic Pain Group to screen for neuropathic pain. METHODS: This prospective observational study was undertaken in three hospitals to assess the validity of a Japanese translation of the DN4. We first translated the DN4 into Japanese using a forward-backward method. Pain specialists then examined patients independently and diagnosed them with neuropathic or non-neuropathic pain, according to the International Association for the Study of Pain definitions. The Japanese version of the DN4 questionnaire was then given to each patient. RESULTS: Of 187 patients that met our inclusion criteria, 100 and 87 were diagnosed with neuropathic and non-neuropathic pain, respectively. The test-retest intra-class correlation coefficient (95% confidence interval) was 0.827 (0.769-0.870). Among patients with identical diagnoses of neuropathic or non-neuropathic pain, receiver-operating characteristic curve analysis revealed an area under the curve of 0.89. A cut-off point of equal or greater than 4 resulted in a sensitivity of 71% and specificity of 92%. CONCLUSION: The Japanese version of the DN4 was found to be a helpful tool for discriminating between neuropathic and non-neuropathic pain.

Transient Receptor Potential Channels as Blood Biomarkers for Pain Characteristics in Patients with Chronic Pain.

Transient receptor potential (TRP) channels play key roles for the transition from acute to chronic postoperative pain after surgery. To evaluate TRP channels in the peripheral blood cells as blood biomarkers for chronic pain, we collected blood samples for genome-wide assays of the mRNA expression and assessed pain intensity and the number of pain symptoms in 13 patients with chronic pain. There was a significant association between increases in the number of pain symptoms and increases in the TRP vanilloid 1 (TRPV1) expression. Decreases in the TRP ankyrin 1 (TRPA1) expression, however, tended to increase the number of pain symptoms. There was likely an inverse relationship for TRPV1 and TRPA1 expressions with regard to the number of pain symptoms in chronic pain patients.

Correlation Between DNA Methylation of TRPA1 and Chronic Pain States in Human Whole Blood Cells.

OBJECTIVES: Neuro-immune interactions with functional changes in the peripheral blood cells including changes in the transient receptor potential ankyrin 1 (TRPA1) appear to play a pivotal role in the development of chronic pain in humans. The aim of this study was to examine the association between TRPA1 DNA methylation in whole blood cells and the pain states in chronic pain patients. METHODS: After collecting blood samples from 12 chronic pain patients, the authors measured DNA methylation levels in whole blood cells. Significant associations between the patient's demographic data and the chronic pain states were determined by a multiple linear regression analysis that used age, body mass index, pain duration, depression, anxiety, cognitive impairment, activities of daily living, neuropathic pain, and pain states as the dependent variables, and the TRPA1 DNA methylation levels as the independent variables. RESULTS: Multiple regression analysis revealed a significant correlation between increases of the methylation levels of the CpG island in the TRPA1 gene and increases in the number of neuropathic pain symptoms, which were evaluated using the Douleur Neuropathique 4 (DN4) questionnaire. Decreases in the TRPA1 mRNA expression were also significantly related to increases in the DN4 score. The presence of a burning sensation, which is one of pain symptoms in the DN4 questionnaire, was significantly correlated with the increase in DNA methylation level of TRPA1. CONCLUSIONS: TRPA1 DNA methylation levels in whole blood cells appear to be associated with pain symptoms in chronic pain patients.

[Anesthetic management of a patient with pulmonary hypertension due to a large anterior mediastinal tumor anticipated by preoperative computed tomography].

A 74-year-old man underwent an operation for an extremely large mediastinal tumor. Despite the lack of respiratory difficulty or distention of the jugular veins, preoperative computed tomography showed suppression of the left atrium by the huge tumor. We suspected pulmonary hypertension and monitored continuously with a pulmonary catheter. The Pp/Ps ratio decreased gradually from 0.8 to 0.7 by continuous administration of alprostadil or olprinone. After tumor resection, the Pp/Ps ratio was reduced and maintained at 0.2 even after alprostadil and olprinone administration was discontinued. The tumor was considered to have caused the severe pulmonary hypertension, as anticipated from the preoperative CT.

[Case of Takotsubo cardiomyopathy after induction of general anesthesia].

Takotsubo cardiomyopathy is a cardiac syndrome characterized by transient left ventricular dysfunction. A 79-year-old woman was scheduled for posterior lumbar interbody fusion for spinal compression fracture. After induction of general anesthesia, her blood pressure collapsed with significant ST rise in I, aVL, V3-V5. Emergent transthoracic echocardiography revealed excessive contraction of the base and severe hypokinesis of the apex suggesting Takotsubo cardiomyopathy. Chronic hypovolemia and electrolyte disorder due to habitual glycerin enema were considered to be causes of this sudden cardiac collapse.

[Effective reversal of muscle relaxation by rocuronium using sugammadex in a patient with myasthenia gravis undergoing laparoscopic cholecystectomy].

As myasthenia gravis affects neuromuscular transmission, these patients show various responses to neuromuscular blocking drugs. We report a successful use of the sugammadex in a myasthenic patient to reverse rocuronium-induced neuromuscular block. A 69-year-old woman was scheduled for laparoscopic cholecystectomy and total of rocuronium 20 mg was administered. After spontaneous recovery of T1, we administered sugammadex 200mg intravenously, reversing neuromuscular blockade to a train-of-four ratio (T4/T1) of 100% within 30 sec. Sugammadex can be used to reverse rocuronium-induced neuromuscular blockade in patients with myasthenia gravis, thereby avoiding the need for reversal with acetylcholinesterase inhibitors.