Takahiro Ushida

Contralateral thalamic perfusion in patients with reflex sympathetic dystrophy syndrome

Iodine-123-labelled iodoamphetamine single-photon emission computed tomography of patients with reflex sympathetic dystrophy syndrome showed substantial variation in thalamic perfusion of the side contralateral to the painful limb. The variations are related to time from the onset of symptoms, which suggests that the thalamus undergoes adaptive changes in the course of this neurological disorder.

Analgesic effects of ketamine ointment in patients with complex regional pain syndrome type 1

Objective Ketamine hydrochloride (KET), an agent used for general anesthesia, has local anesthetic effects and N-methyl-d-aspartate (NMDA) receptor antagonist action. Because recent studies emphasized the role of peripherally distributed NMDA receptors in processing the nociceptive information, we investigated whether peripheral application of the ointment containing KET is able to attenuate the symptoms of local neuropathic pain. Case Reports We applied ointment containing KET (0.25%-1.5%) to the affected area on limbs in 5 patients with complex regional pain syndrome type I (CRPS I) and in 2 patients with type II (CRPS II). One to 2 weeks later, we observed improvement of the report of pain intensity, measured by the visual analog scale, in 4 patients with acute early dystrophic stage of CRPS I. Swelling of the affected limbs subsided as well. No apparent changes were noticed in 1 patient with chronic atrophic stage of CRPS I and in both patients with CRPS II. Conclusion Topical application of KET appears to be beneficial for the patients with acute early dystrophic stage of CRPS I because of either its local anesthetic effect or NMDA receptor antagonist action. Patients with chronic atrophic stage of CRPS I and CRPS II patients do not appear to respond to this treatment.

Percutaneous Radiofrequency Treatment for Refractory Anteromedial Pain of Osteoarthritic Knees

OBJECTIVE Although severe knee osteoarthritis with refractory pain is commonly treated surgically, this is often not an option for patients with poor health status or unwillingness to undergo major surgery. We examined the efficacy of radiofrequency application to sensory nerves as a novel alternative treatment for refractory knee pain. METHODS This study was an open-label, nonrandomized, and controlled study. Patients complaining of refractory anteromedial knee pain associated with radiological osteoarthritis (moderate or severe) were included. They were assigned to one of two groups: those receiving radiofrequency thermocoagulation (N = 18) or those receiving nerve block (N = 17), depending on the time period that they were referred to the clinic. Radiofrequency current or local anesthetics was applied to the medial retinacular nerve and the infrapatellar branch of the saphenous nerve. Western Ontario McMaster Universities osteoarthritis index score, pain visual analog scale (VAS), and patients global assessment were assessed with a minimum follow-up of 6 months. RESULTS   Radiofrequency treatment significantly decreased knee pain as measured by VAS for 12 weeks compared with the control group. In terms of responders, more patients in the RF group responded to the treatment than in the control group. The differences were statistically significant at 4 weeks, 8 weeks, and 12 weeks in pain VAS. Eight patients (44%) treated with radiofrequency rated excellent or good but only three (18%) in the control group rated good, although the difference was not statistically significant. CONCLUSIONS Some patients were able to benefit substantially from radiofrequency treatment. Even if its effective period is limited, radiofrequency application is a promising treatment to alleviate refractory anteromedial knee pain with osteoarthritis. Further experience and technical improvements are needed to establish its role in the management of knee osteoarthritis.

Comparative Effects of Acupressure at Local and Distal Acupuncture Points on Pain Conditions and Autonomic Function in Females with Chronic Neck Pain

Acupressure on local and distal acupuncture points might result in sedation and relaxation, thereby reducing chronic neck pain. The aim was to investigate the effect of acupressure at local (LP) and distal acupuncture points (DP) in females with chronic neck pain. Thirty-three females were assigned to three groups: the control group did not receive any stimuli, the LP group received acupressure at local acupuncture points, GB 21, SI 14 and SI 15, and the DP group received acupressure at distal acupuncture points, LI 4, LI 10 and LI 11. Verbal rating scale (VRS), Neck Disability Index (NDI), State-Trait Anxiety Inventory (STAI), muscle hardness (MH), salivary alpha-amylase (sAA) activity, heart rate (HR), heart rate variability (HRV) values and satisfaction due to acupressure were assessed. VRS, NDI, STAI and MH values decreased after acupressure in the LP and the DP group. HR decreased and the power of high frequency (HF) component of HRV increased after acupressure in only the LP group. Although acupressure on not only the LP but also the DP significantly improved pain conditions, acupressure on only the LP affected the autonomic nervous system while acupuncture points per se have different physical effects according to location.

Intraoperative electroneurography in the assessment of the level of operation for cervical spondylotic myelopathy in the elderly

We treated 31 patients aged 65 years or more with cervical spondylotic myelopathy by microsurgical decompression and fusion at a single most appropriate level, in spite of MRI evidence of compression at several levels. Spinal cord potentials evoked at operation localised the level responsible for the principal lesion at C3-4 in 18 patients, C4-5 in 11 and at C5-6 in two. Despite the frequent coexistence of other age-related conditions, impairing ability to walk, the average Nurick grade improved from 3.5 before operation to 2.2 at a mean follow-up of 48 months. There was also good recovery of finger dexterity and sensitivity. Operation at a single optimal level, as opposed to several, has the advantage of minimising complications, of particular importance in this age group.

The effect of acupressure at the extra 1 point on subjective and autonomic responses to needle insertion.

BACKGROUND: Premedication with sedatives can decrease the discomfort associated with invasive anesthetic procedures. Some researchers have shown that acupressure on the acupuncture extra 1 point is effective for sedation. We investigated whether acupressure on the extra 1 point could alleviate the pain of needle insertion. METHODS: We investigated the effect of acupressure at the extra 1 point or a sham point on needle insertion using verbal rating scale (VRS) pain scores and heart rate variability (HRV). Twenty-two healthy female volunteers were randomly allocated to two groups: the extra 1 group received acupressure at the extra 1 point, and the sham group received acupressure at a sham point. After starting the electrocardiogram record, a 27-gauge needle was inserted into the skin of a forearm. Thereafter, another needle was inserted into the skin of the other forearm during acupressure. RESULTS: Acupressure at the extra 1 point significantly reduced the VRS, but acupressure at the sham increased the VRS. Acupressure at the extra 1 significantly reduced the low frequency/high frequency ratio of HRV responding to needle insertion. CONCLUSIONS: Acupressure at the extra 1 point significantly reduced needle insertion pain compared with acupressure at the sham point. Also, acupressure at the extra 1 point significantly reduced the low frequency/high frequency ratio of HRV responding to needle insertion, which implies a reduction in sympathetic nervous system activity.

Incidence and Risk Factors of Postoperative Delirium in Cervical Spine Surgery

Study Design. Retrospective clinical review and prospective report of postoperative delirium after cervical spine surgeries. Objective. To investigate factors contributing to the development of delirium after cervical surgery and see whether amended therapeutic protocols could improve or alter postoperative outcomes. Summary of Background Data. Important consequences of postoperative delirium for the orthopedic patients include impaired recovery and increased morbidity and mortality. Although its risk factors have been reported in orthopedic surgery, there are a very few reports regarding postoperative delirium in spine surgery. Methods. Eighty-one cervical myelopathy patients were retrospectively examined about the incidence of postoperative delirium and the risk factors. Similarly, 41 patients who received postoperative care under modified protocols were prospectively examined. Results. Postoperative delirium occurred more commonly in patients over 70 years and those with hearing impairment. Patients who received high-dose methylprednisolone (>1000 mg) demonstrated an increased incidence of postoperative delirium. Under modified protocol, we reduced the usage of methylprednisolone and encouraged free body movement with cervical orthosis immediately after surgery. The incidence of postoperative delirium was significantly lower under the modified protocol. Conclusion. Early commencement of mobilization after cervical spine surgery would be crucial to the prevention of postoperative delirium in the elderly.

Visualization of Painful Experiences Believed to Trigger the Activation of Affective and Emotional Brain Regions in Subjects with Low Back Pain

In the management of clinical low back pain (LBP), actual damage to lower back areas such as muscles, intervertebral discs etc. are normally targeted for therapy. However, LBP may involve not only sensory pain, but also underlying affective pain which may also play an important role overall in painful events. Therefore we hypothesized that visualization of a painful event may trigger painful memories, thus provoking the affective dimension of pain. The present study investigated neural correlates of affect processing in subjects with LBP (n = 11) and subjects without LBP (n = 11) through the use of virtual LBP stimuli. Whole brain functional magnetic resonance imaging (MRI) was performed for all subjects while they were shown a picture of a man carrying luggage in a half-crouching position. All subjects with LBP reported experiencing discomfort and 7 LBP subjects reported experiencing pain. In contrast to subjects without LBP, subjects with LBP displayed activation of the cortical area related to pain and emotions: the insula, supplementary motor area, premotor area, thalamus, pulvinar, posterior cingulate cortex, hippocampus, fusiform, gyrus, and cerebellum. These results suggest that the virtual LBP stimuli caused memory retrieval of unpleasant experiences and therefore may be associated with prolonged chronic LBP conditions.

The Influence of Acupressure at Extra 1 Acupuncture Point on the Spectral Entropy of the EEG and the LF/HF Ratio of Heart Rate Variability

Acupressure applied on the Extra 1 acupuncture point results in sedation, thereby reducing bispectral index (BIS) values. Mental status and hypnotic agents influence the autonomic nervous system. We hypothesized that acupressure at the Extra 1 point would induce sedation and change sympatho-parasympathetic nerve balance. We investigated the effect of acupressure at the Extra 1 point on the EEG spectral entropy values and heart rate variability (HRV). Forty-eight volunteers (24 males and 24 females) were randomly assigned to the control or Extra 1 group. The control group received acupressure at a sham point and the Extra 1 group received acupressure at the Extra 1 point. Acupressure was applied for 5 min. The record of the EEG spectral entropy values and HRV started 5 min before acupressure and stopped 5 min after acupressure. Acupressure significantly reduced the EEG spectral entropy values in both groups, but the values of the Extra 1 group were significantly smaller than those of the control group (P < .01). Acupressure significantly decreased the LF/HF ratio of HRV in both groups (P < .05). When divided upon gender, although acupressure tended to decrease the LF/HF ratio, the ratio significantly decreased during and after acupressure only in females of the Extra 1 group (P < .05). We concluded that acupressure on the Extra 1 point significantly reduced the EEG spectral entropy in both the genders, but affected the LF/HF ratio of HRV only in females.

Peripheral administration of an N-methyl-d -aspartate receptor antagonist (MK-801) changes dorsal horn neuronal responses in rats

Due to the discovery of peripheral N-methyl-D-aspartate (NMDA) receptors, the effects of peripherally administrated MK-801, a non-competitive NMDA receptor antagonist, and phosphate buffered saline were tested by using the response changes of wide-dynamic range cells in the lumbar enlargement of the spinal cord in Sprague-Dawley rats. MK-801 (1 microM, 50 microl) administered directly into the subcutaneous tissue of the receptive field (n = 7), produces a reversible reduction of responses to noxious and innocuous stimuli by a peripheral action. There was no change in the responses to cutaneous stimuli following injection of phosphate buffered saline (n = 7) or following administration of MK-801 into the contralateral foot (n = 7). The present study suggests that MK-801 produces a local anesthetic like effect in the peripheral tissue.