High-Frequency Repetitive Transcranial Magnetic Stimulation Reduces Pain in Postherpetic Neuralgia.

OBJECTIVES: Postherpetic neuralgia (PHN) is one of the most intractable pain disorders, especially in elderly patients. There is evidence that repetitive transcranial magnetic stimulation (rTMS) reduces neuropathic pain; however, its effectiveness for PHN is unknown. This study investigated the efficacy of high-frequency rTMS in patients with PHN. DESIGN: A total of 40 patients were randomly assigned to receive 10 sessions of real or sham rTMS of the primary motor cortex. Each stimulation session consisted of a series of 300 five-second pulses with a frequency of 10 Hz and an interval of 3 seconds between each train, giving a total of 1500 pulses per session. The primary outcome was pain intensity measured before stimulation from first intervention (T0) to the final stimulation (T10), and 1 and 3 months after final stimulation (T11 and T12). Other outcomes measured included scores on the short form McGill pain questionnaire, self-rating depression scale, quality of life (QOL), sleep quality, the patient global impression of change, medication regulation, and reported adverse events. RESULTS: The real rTMS group demonstrated greater reduction of visual analogue scale (VAS) than the sham group at each time point except for T0 (P = 0.399) and T1 (P = 0.091). Mean VAS reduction in the real rTMS group was 16.89% for duration of disease longer than 6 months. These analgesic effects were associated with long-term improvement in rating-scale items related to QOL. CONCLUSION: The results suggest that rTMS is an effective and safe therapy in patients with PHN.

Long-term outcome of computed tomography-guided percutaneous radiofrequency thermocoagulation for classic trigeminal neuralgia patients older than 70 years.

The incidence of trigeminal neuralgia (TN) in elderly patients is higher. However, for those with poor fitness, the optimal surgical treatment for those refractory to medical treatment is controversial. The aim of current study was to investigate the long-term outcome of computed tomography (CT)-guided percutaneous radiofrequency thermocoagulation (PRT) for 304 TN patients 70 years or older. We conducted a retrospective study of 304 elderly patients with TN who were treated with CT-guided PRT between 2002 and 2012. Follow-up was censored at the time of last contact, additional surgery, or death. Sixty-seven patients (22.1%) were of more than American Society of Anesthesiologists classification system physical status II. Excellent pain relief was 100% at discharge, 85% at 1 year, 75% at 3 years, 71% at 5 years, and 49% at 10 years. Pain relief outcomes were correlated with facial numbness. Lower temperature group (≤75°C) can attain the same long-term pain relief as higher temperature group (≥80°C); however, the incidence of painful dysesthesia rate of higher temperature group was higher than lower temperature group. Postoperative morbidity included facial numbness, masseter weakness, corneitis, hearing loss, dropping eyelid, and limited mouth opening. There were no mortalities observed during or after PRT. Our result showed CT-guided PRT is safe and effective for classic TN patients 70 years or older, including poor-fitness patients (American Society of Anesthesiologists classification system physical status >II). Lower temperature (≤75°C) is recommended for PRT in the treatment of TN.

Repeated CT-guided percutaneous radiofrequency thermocoagulation for recurrent trigeminal neuralgia.

AIMS: To investigate the long-term outcomes of repeated percutaneous radiofrequency thermocoagulation (PRT) for recurrent trigeminal neuralgia (TN) patients. METHODS: Between 2002 and 2012, 33 patients with recurrent TN following an initial PRT procedure were retrospectively studied and underwent 43 repeated PRT procedures. RESULTS: The mean length of follow-up after repeated PRT was 34 months. Pain relief was immediate in 30 patients (90.9%), and no pain relief occurred in 3 patients (9.1%) following a second PRT procedure. The percentage of patients who remained in an 'excellent' and 'good' pain relief condition (pain intensity ≤BIN grade III) after the second PRT procedure was 75% at 1 year, 68% at 2 years and 68% at 5 years, and 22 of these patients (54.5%) remained satisfied with their pain relief during the follow-up period. Nine patients underwent PRT three times and 1 patient four times. The total number of patients who benefited from repeated PRT was 28 (84.8%). Postprocedure complications including masseter weakness were present in 3 patients and limited mouth opening affected 1 patient. No mortalities were observed during or after repeated PRT procedures. CONCLUSION: Repeated PRT provides long-term pain relief benefits to patients with recurrent TN and should be considered as an alternative treatment for recurrent TN.

Anterior herniation of lumbar disc induces persistent visceral pain: discogenic visceral pain: discogenic visceral pain.

BACKGROUND: Visceral pain is a common cause for seeking medical attention. Afferent fibers innervating viscera project to the central nervous system via sympathetic nerves. The lumbar sympathetic nerve trunk lies in front of the lumbar spine. Thus, it is possible for patients to suffer visceral pain originating from sympathetic nerve irritation induced by anterior herniation of the lumbar disc. This study aimed to evaluate lumbar discogenic visceral pain and its treatment. METHODS: Twelve consecutive patients with a median age of 56.4 years were enrolled for investigation between June 2012 and December 2012. These patients suffered from long-term abdominal pain unresponsive to current treatment options. Apart from obvious anterior herniation of the lumbar discs and high signal intensity anterior to the herniated disc on magnetic resonance imaging, no significant pathology was noted on gastroscopy, vascular ultrasound, or abdominal computed tomography (CT). To prove that their visceral pain originated from the anteriorly protruding disc, we evaluated whether pain was relieved by sympathetic block at the level of the anteriorly protruding disc. If the block was effective, CT-guided continuous lumbar sympathetic nerve block was finally performed. RESULTS: All patients were positive for pain relief by sympathetic block. Furthermore, the average Visual Analog Scale of visceral pain significantly improved after treatment in all patients (P < 0.05). Up to 11/12 patients had satisfactory pain relief at 1 week after discharge, 8/12 at 4 weeks, 7/12 at 8 weeks, 6/12 at 12 weeks, and 5/12 at 24 weeks. CONCLUSIONS: It is important to consider the possibility of discogenic visceral pain secondary to anterior herniation of the lumbar disc when forming a differential diagnosis for seemingly idiopathic abdominal pain. Continuous lumbar sympathetic nerve block is an effective and safe therapy for patients with discogenic visceral pain.

The kappa-opioid receptor is upregulated in the spinal cord and locus ceruleus but downregulated in the dorsal root ganglia of morphine tolerant rats.

As a non-selective agonist of opioid receptors, morphine can also act on the kappa-opioid receptor (KOR) when activating the mu-opioid receptor (MOR) and delta-opioid receptor (DOR). Although previous findings indicate that KOR plays an important role in morphine analgesia and antinociceptive tolerance, the reasons for the paradoxical functions of KOR in analgesia and anti-analgesia responses are still unclear. The aim of this study was to explore the role of the KOR in morphine analgesia and antinociceptive tolerance. As such, the changes in KOR expression in different regions of the nervous system in morphine tolerant rats were examined. We were able to attain morphine tolerance in rats via subcutaneous injection of morphine (10 mg/kg) twice daily for 7-consecutive days. Competitive real-time PCR, immunohistochemistry, and Western blot analyses were used to assess KOR expression in related regions of the nervous system, including the thalamus, hypothalamus, hippocampus, locus ceruleus (LC), periaqueductal gray (PAG), lumber-sacral spinal cord, and dorsal root ganglia (DRG). The expression of KOR increased in the locus ceruleus and spinal cord, but was significantly decreased in the DRG of morphine tolerant rats (P<0.05). No other significant changes in KOR expression were observed in the other regions. Consequently, we propose that the locus ceruleus and spinal cord are likely the dominant CNS regions and the DRG is the main peripheral site in which chronic morphine exerts its effect on KOR. Prolonged morphine administration induces inconsistent changes of KOR in the central and peripheral nervous system.

[Effect of fentanyl on expression of mu-receptor and beta-arrestin 2 in periaqueductal gray of rats tolerant to morphine].

OBJECTIVE: To investigate the effect of fentanyl upon the expression of mu-receptor and beta-arrestin 2 in peri-aqueductal gray of morphine-tolerant rats. METHODS: Forty male SD rats weighing (230 +/- 20) g were randomly divided into 5 groups of eight animals each: group NS, group M, group MF1, group MF2 and group MF3. Rats in group NS received only subcutaneous normal saline 1 ml/kg twice a day for 9 consecutive days; group M received subcutaneous morphine 10 mg/kg followed by NS 1 ml/kg twice a day for 9 consecutive days; In groups MF1, MF2 and MF3, morphine 10 mg x kg(-1) was injected subcutaneously followed by fentanyl 3, 6, 12 microg/kg respectively. All animals were sacrificed at Day 9 after measurement of pain threshold. Periaqueductal gray was removed for determination of the expression of mRNA (RT-PCR) and protein (Western-blot) of mu-receptor and beta-arrestin 2. RESULTS: Compared with group NS, TFL of group M was significantly elevated after the first morphine injection (P < 0.01). But TFL of group M returned to the baseline value after chronic morphine treatment. Compared with group M, TFL increased in groups MF2 and MF3 at Days 7 and 9 (P < 0.05 or 0.01). However, TFL of group MF1 was negative (P > 0.05). The expression of mu-receptor mRNA and protein was significantly lower in group M than in group NS (P < 0.01). Compared with group M, the expressions of mu-receptor mRNA and protein were significantly elevated in group MF2 and MF3 (P < 0.05 or 0.01) but there was no significant change in group MF1 (P > 0.05). The expression of beta-arrestin 2 mRNA and protein significantly decreased in group M as compared with group NS (P < 0.01). Compared with group M, the expressions of beta-arrestin 2 mRNA and protein were significantly elevated in group MF2 and MF3 (P < 0.05 or 0.01), but there was no significant change in group MF1 (P > 0.05). CONCLUSION: Fentanyl at 6 and 12 microg/kg can partly inhibit morphine tolerance through an increased expression of mu-receptor and beta-arrestin 2 in periaqueductal gray of morphine-tolerant rats.

Circulatory responses to nasotracheal intubation: comparison of GlideScope videolaryngoscope and Macintosh direct laryngoscope.

BACKGROUND: The GlideScope videolaryngoscope (GSVL) has been shown to have no special advantage over the Macintosh direct laryngoscope (MDL) in attenuating the circulatory responses to orotracheal intubation, but no study has compared the circulatory responses to nasotracheal intubation (NTI) using the two devices. This prospective randomized clinical study was designed to determine whether there was a clinically relevant difference between the circulatory responses to NTI with the GSVL and the MDL. METHODS: Seventy-six adult patients were randomly allocated equally to the GSVL group and the MDL group. After induction of anesthesia, NTI was performed. Non-invasive blood pressure (BP) and heart rate (HR) were recorded before induction (baseline values) and immediately before intubation (post-induction values), at intubation and every minute for a further five minutes. During the observation, times required to reach the maximum values of systolic BP (SBP) and HR, times required for recovery of SBP and HR to postinduction values and incidence of SBP and HR percent changes > 30% of baseline values were also noted. The product of HR and systolic BP, i.e. rate pressure product (RPP), and the areas under SBP and HR vs. time curves (AUC(SBP) and AUC(HR)) were calculated. RESULTS: The NTI with the GSVL resulted in significant increases in BP, HR and RPP compared to postinduction values, but these circulatory changes did not exceed baseline values. BPs at all measuring points, AUC(SBP), maximum values of BP and incidence of SBP percent increase > 30% of baseline value during the observation did not differ significantly between groups. However, HR and RPP at intubation and their maximum values, AUC(HR) and incidence of HR percent increase > 30% of baseline value were significantly higher in the MDL group than in the GSVL group. Times required for recovery of SBP and HR to postinduction values were significantly longer in the MDL group than in the GSVL group. CONCLUSIONS: The pressor response to NTI with the GSVL and the MDL was similar, but the tachycardiac response to NTI was lesser and of a shorter duration when using a GSVL than when using an MDL.

[Comparison of cardiovascular responses between orotracheal and nasotracheal intubation with the aid of GlideScope video laryngoscope].

OBJECTIVE: To compare the cardiovascular responses to orotracheal or nasotracheal intubation with the aid of GlideScope video laryngoscope (GSVL). METHODS: Sixty patients, American Society of Anesthesiologists (ASA) physical status I, aged 16-50 years, scheduled for elective plastic surgery under general anesthesia,were randomly allocated equally to the orotracheal intubation group (OTI group) and the nasotracheal intubation group (NTI group). After the routine anesthesia induction, orotracheal and nasotracheal intubation was respectively performed with the aid of GSVL. Non-invasive blood pressure and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), during intubation and every minute for 5 minutes after intubation. Maximum values of blood pressure and HR during the observation periods were recorded. The product of HR and systolic blood pressure [rate pressure product (RPP)] at every time point was calculated. Duration for glottis exposure and duration for successful intubation were also noted. RESULTS: There were no significant differences between two groups in the demographic data (P>0.05). Glottis exposure time and intubation time in NTI group were significantly longer than those in OTI group [(52.2+/-13.5) seconds vs. (40.5+/-15.2) seconds, P<0.05]. After anesthesia induction, blood pressure and RPP in both groups decreased significantly compared with baseline values, but no significant change in HR was noted. Compared with their postinduction values, the blood pressure and RPP in both groups and HR in OTI group increased significantly at intubation. In OTI group,the maximum values of HR, diastolic blood pressure (DBP), mean arterial pressure (MAP), RPP exceeded their baseline values. But in NTI group,only maximal HR during the observation period was significantly higher than the baseline values. The blood pressure at every time point was not significantly different between two groups. But intubation in OTI group caused significant increases in HR and RPP compared with those in NTI group (both P<0.05). CONCLUSION: In anesthetized adult patients, orotracheal and nasotracheal intubations with the GSVL can result in a similar pressor response, however orotracheal intubation with GSVL causes more marked cardiovascular responses than nasotracheal intubation with the aid of GSVL.

Hemodynamic responses to tracheal intubation with the Glidescope videolaryngoscope: a comparison of oral and nasal routes.

BACKGROUND: Although there have been numerous favorable reports on the uses of the GlideScope videolaryngoscope (GSVL) in oral and nasal intubations, no study has compared the hemodynamic responses to oral and nasal intubations with the GSVL in a single clinical trial. The purpose of this randomized clinical study was to determine whether there was a clinically relevant difference between the hemodynamic responses to oral and nasal intubations with the GSVL. METHODS: A total of 71 patients, ASA physical status I, aged 18-50 years, scheduled for elective plastic surgery under general anesthesia, were randomly allocated to the oral intubation group (OI group) and the nasal intubation group (NI group). Noninvasive blood pressure (BP) and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation and every minute for a further 5 minutes. Maximum values of BP and HR during the observation were noted. The product of HR and systolic blood pressure (rate pressure product, RPP), the percent changes of systolic blood pressure (SBP) and HR relative to the baseline values at every measuring point, and the areas under the SBP and HR versus time curves were calculated. RESULTS: The intubation time was significantly longer in the NI group than in the OI group. The total incidence of difficulties encountered during laryngoscopy and intubation were higher in the OI group than in the NI group (29% vs. 6%, p < 0.05). BP at all measuring points, the maximum values of BP, the area under the SBP versus time curve, and the incidence of SBP percent increase more than 30% of baseline value did not differ significantly between the two groups. However, HR and RPP at intubation and their maximum values during the observation, the area under the HR versus time curve, and the incidence of HR percent increase more than 30% of baseline value were significantly higher in the OI group than in the NI group (p < 0.05). As compared with the NI group, the times required to reach the maximum values of SBP and HR were significantly shorter and the times required for recovery of SBP and HR to postinduction values were significantly longer in the OI group (p < 0.05). CONCLUSION: In anesthetized adult patients, oral and nasal intubations with the GSVL can result in a similar pressor response. However, the tachycardic response to nasal intubation using a GSVL is smaller and of shorter duration than that to oral intubation using a GSVL.

[Comparison of hemodynamic responses to nasotracheal intubations with Glide Scope video-laryngoscope, Macintosh direct laryngoscope, and fiberoptic bronchoscope].

OBJECTIVE: To compare the hemodynamic responses to nasotracheal intubation with Glide Scope video-laryngoscope (GSVL), Macintosh direct laryngoscope (MDLS), and fiberoptic bronchoscope (FOB). METHODS: Sixty patients, with American Society of Anesthesiologists (ASA) physical status I - II, aged 18- 50 years, and scheduled for elective plastic surgery under general anesthesia requiring nasotracheal intubation, were randomly allocated equally to GSVL group, MDLS group, and FOB group. After the routine anesthesia induction, nasotracheal intubation was performed with the GSVL, MDLS, and FOB, respectively. Noninvasive blood pressure (BP) and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation, and subsequently at an interval of every 1 minute for a total of five minutes. The maximum and minimum values of BP and HR during the observation period were also noted. The rate pressure product (RPP) at each measuring time point was calculated. The areas under effect-time curve (AUE) of hemodynamics were calculated by time as X-axis and changes of BP and HR during the observation as Y-axis. RESULTS: All the three groups were similar in the demographic data and intubation time. After anesthesia induction, BP and RPP in all the three groups decreased significantly compared to baseline values (P < 0. 05), while HR had no significant change. After nasotracheal intubation, BP, HR, and RPP in all three groups were significantly higher than the postinduction values (P < 0.05). In the FOB group, BP, HR, and RPP at intubation significantly increased when compared with the baseline values (P < 0.05). In the MDLS group, HR at intubation, and maximum values of diastolic blood pressure (DBP), mean arterial pressure (MAP), HR, and RPP during the observation were significantly higher than the baseline values (P < 0.05). In the GSVL group, all hemodynamic parameters at intubation and after intubation were not significantly different from the baseline values. BP, HR, and RPP at intubation, and the incidences of HR more than 100 bpm during the observation were significantly higher in the FOB group than in the other two groups (P < 0.05). BP was not significantly different during the observation between the MDLS and GSVL groups, but HR and RPP at intubation and after intubation as well as AUE(HR) were significantly higher in the MDLS group than in the GSVL group (P < 0.05). AUE(HR) and AUE(SBP) were significantly lower in the GSVL group than in the FOB group (P < 0.05). CONCLUSION: The hemodynamic responses to nasotracheal intubation are most severe with FOB, followed by MDLS, and then GSVL.

[Comparison of hemodynamic responses to orotracheal intubation between using GlideScope videolaryngoscope and fiberoptic bronchoscope].

OBJECTIVE: To compare the hemodynamic responses to orotracheal intubation with GlideScope videolaryngoscope (GSVL) and with fiberoptic bronchoscope (FOB) after induction of general anesthesia. METHODS: Totally 57 ASA physical status I - II adult patients undergoing elective plastic surgery and requiring orotracheal intubation were randomly allocated to either GSVL group (n = 29) or FOB group (n = 28). After a routine intravenous anesthetic induction, orotracheal intubation was performed. Noninvasive blood pressure (BP) and heart rate (HR) were recorded before and after anesthetic induction, at intubation and thereafter at 1 minute interval for 5 minutes. RESULTS: The intubation time was not significantly different between the two groups (P > 0.05). After intubation, BP and HR exhibited significant increases compared to the post-induction values in both groups, but the maximum values of BP did not exceed the pre-induction values while the maximum value of HR was higher than the pre-induction value. During the observation, BP and HR at all time points as well as the maximum values of BP and HR had no significant differences between the two groups (P > 0.05). CONCLUSION: The orotracheal intubations using FOB and GSVL result in similar hemodynamic responses.