Pyung Bok Lee

Dermatome Variation of Lumbosacral Nerve Roots in Patients with Transitional Lumbosacral Vertebrae

BACKGROUND: The presence of a transitional vertebra can create difficulty in identifying the lumbar level corresponding to an exiting nerve root at the time of a spinal nerve block. We investigated the possibility that the muscle innervation pattern and sensory dermatomes of the lumbar nerve roots are altered when a lumbosacral transitional vertebra is present using electrical stimulation. METHODS: We determined the existence of transitional vertebrae using Castellvi’s criteria. Patients having transitional vertebrae with lumbosacral radiculopathy were recruited for the study. Selective nerve root blocks using electrical stimulation were performed. Neurologic symptoms caused by S1 or L5 nerve root compression in the patients with a lumbarized S1 or sacralized L5, respectively, were compared with those caused by either L5 or S1 nerve root compression in patients with a normal configuration. RESULTS: Thirty-two patients had transitional vertebrae, of whom 12 had a lumbarized S1 and 20 had a sacralized L5. The distribution of motor and sensory symptoms caused by the lumbarized S1 (L6) nerve root stimulation was similar to that of the S1 nerve root stimulation in the normal configuration. In 17 patients, the distribution of motor and sensory symptoms caused by the sacralized L4 nerve root stimulation was similar to that of L5 nerve root stimulation in the normal configuration. CONCLUSIONS: Our findings suggest that the function of the lumbosacral nerve roots is altered in patients with a sacralized L5, and that the L4 nerve root serves the usual function of the L5 nerve root.

Comparison between high and low molecular weight hyaluronates in knee osteoarthritis patients: open-label, randomized, multicentre clinical trial.

Efficacy and safety of high and low molecular weight hyaluronates in knee osteoarthritis patients were compared in a randomized, open-label trial. Patients in the high molecular weight hyaluronate group were treated once weekly for 3 weeks and in the low molecular weight group once weekly for 5 weeks. We evaluated weight-bearing pain, degree of flexion, swelling and knee tenderness; frequency and amount of rescue medication; patient and investigator global assessment of pain, and safety over 12 weeks after final injection of study medication. Significant improvements in pain and WOMAC-Likert scores were observed in both groups, but not between groups. Knee joint pain improvement was noted in both groups by patients and investigators during follow-up. Close correlation was observed between patient-and investigator-reported data. There was no significant difference in side-effects between the groups. In conclusion, the efficacy and safety of high and low molecular weight hyaluronate are similar.

Early thoracic sympathetic block improves the treatment effect for upper extremity neuropathic pain.

BACKGROUND: The sympathetic nervous system has important roles in mediating many neuropathic pain conditions. A thoracic sympathetic block (TSB) is a useful therapeutic procedure for neuropathic pain in the upper extremities and thorax. However, no studies have examined the factors related to an improved therapeutic effect of TSB. In this study, we evaluated the influence of potential prognostic factors for a better TSB effect and identified clinically important prognostic factors. METHODS: Percutaneous TSB was performed in 51 patients, under fluoroscopic guidance. Data collected for each patient included age, gender, body mass index, diagnosis, pain intensity, and symptom duration. The adjusted odds ratios and 95% confidence intervals for each variable were calculated by logistic regression. RESULTS: TSB was more effective in patients with symptom durations of ⩽1 year compared with >1 year (P = 0.006; odds ratio, 8.037; 95% confidence interval, 1.808–35.729). Patient age, gender, body mass index, diagnosis, and intensity of pre-TSB pain were not associated with TSB effectiveness. CONCLUSION: The results showed that an earlier TSB produced a better outcome for patients with chronic pain syndrome. Thus, early TSB should be performed in patients with chronic pain in the upper extremities.

The neurological safety of epidural gabapentin in rats: a light microscopic examination.

Gabapentin acts primarily on the central nervous system. Therefore, we hypothesized that the direct epidural administration of gabapentin could have various advantages over its oral administration with respect to required dose, side effects, and efficacy. However, before administering gabapentin into the epidural space in a clinical setting, its neurotoxicity must be examined in animals. Thus, we evaluated neurotoxicity of epidural gabapentin by observing behavioral and sensory-motor changes, and by histopathological examinations of spinal cords and dorsal root ganglia in the rat. Twenty-seven rats were randomly divided into 3 groups, which were administered 0.3 mL (30 mg) of epidural gabapentin (group G, n = 9) and the same volume of epidural alcohol (group A, n = 9) or normal saline (group N, n = 9). No rats in groups G and N showed sensory-motor dysfunction, behavioral change, or histopathological abnormalities over a 3-wk observation period, whereas all rats in group A showed abnormalities. We conclude that the direct epidural injection of gabapentin in rats did not show any neurotoxic evidence in terms of sensory-motor functions and behavior, or by a microscopic histopathological evaluation. This study represents a first promising step toward the trial of epidural gabapentin in a clinical setting.

Spontaneous lead breakage in implanted spinal cord stimulation systems.

Spinal cord stimulation (SCS) has become an established clinical option for treatment of refractory chronic pain. Current hardware and implantation techniques for SCS are already highly developed and continuously improving; however, equipment failures over the course of long-term treatment are still encountered in a relatively high proportion of the cases treated with it. Percutaneous SCS leads seem to be particularly prone to dislocation and insulation failures. We describe our experience of lead breakage in the inserted spinal cord stimulator to a complex regional pain syndrome patient who obtained satisfactory pain relief after the revision of SCS.

A prospective, open-label, multicenter study of the clinical efficacy of extended-release hydromorphone in treating cancer pain inadequately controlled by other analgesics.

PurposeThe objective of this study was to evaluate whether extended-release hydromorphone (osmotic-controlled release oral delivery system [OROS] hydromorphone) treatment provided pain relief in cancer patients whose pain was inadequately controlled by other analgesics.MethodsIn this prospective, open-label, multicenter trial, patients who have sustained cancer pain with other analgesics were enrolled. After the baseline evaluation (visit 1), OROS hydromorphone was administered. Two evaluations (visits 2 and 3) were made: 29u2009±u20097 and 57u2009±u20097xa0days later, respectively. The primary end point was the pain intensity difference (PID) at visit 3 relative to visit 1 (expressed as percent PID).ResultsIn total, 879 patients were screened and 432 completed all three visits. Of the 874 full analysis set patients, 343 (39.2xa0%) improved by more than 30xa0% PID. Of the 432 per-protocol patients, 282 (65.3xa0%) improved by more than 30xa0% PID. At visits 2 and 3, the degree of sleep disturbance, the number of awakenings, and the degree of sleep satisfaction were significantly better than at visit 1 (all Pu2009<u20090.0001 for both visit 1–visit 2 and visit 1–visit 3). However, this pain relief was not associated with improved quality of life (Pu2009=u20090.326 and Pu2009=u20090.055 for visit 1–visit 2 and visit 1–visit 3, respectively).ConclusionsThis study suggested that active pain management using the strong opioid OROS hydromorphone was beneficial in the management of cancer pain that was not controlled by other analgesics.

Proteomic Identification of Altered Cerebral Proteins in the Complex Regional Pain Syndrome Animal Model

Background. Complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder. Although the exact pathophysiology of CRPS is not fully understood, central and peripheral mechanisms might be involved in the development of this disorder. To reveal the central mechanism of CRPS, we conducted a proteomic analysis of rat cerebrum using the chronic postischemia pain (CPIP) model, a novel experimental model of CRPS. Materials and Methods. After generating the CPIP animal model, we performed a proteomic analysis of the rat cerebrum using a multidimensional protein identification technology, and screened the proteins differentially expressed between the CPIP and control groups. Results. A total of 155 proteins were differentially expressed between the CPIP and control groups: 125 increased and 30 decreased; expressions of proteins related to cell signaling, synaptic plasticity, regulation of cell proliferation, and cytoskeletal formation were increased in the CPIP group. However, proenkephalin A, cereblon, and neuroserpin were decreased in CPIP group. Conclusion. Altered expression of cerebral proteins in the CPIP model indicates cerebral involvement in the pathogenesis of CRPS. Further study is required to elucidate the roles of these proteins in the development and maintenance of CRPS.

The Therapeutic Effect of Vitamin C in an Animal Model of Complex Regional Pain Syndrome Produced by Prolonged Hindpaw Ischemia-Reperfusion in Rats

Objectives: It is known that increased free radicals from oxidative stress are one of the major causes of complex regional pain syndrome (CRPS). In this study, we tested the hypothesis that vitamin C has a dose-related treatment effect in a chronic post-ischemic pain (CPIP) model. Methods: A total of 49 male rats weighing 250 to 350 g were used. The 4 treatment groups were control (no medication), group 1.0 (administration of 1 mg/day for vitamin C for 5 days), group 2.5 (administration of 2.5 mg/day vitamin C for 5 days), and group 7.5 (administration of 7.5 mg/day vitamin C for 5 days). The 50% mechanical withdrawal threshold and total blood antioxidant status (TAS) were measured before and after administration of vitamin C. Results: Twenty-eight CPIP model rats were generated from 49 rats. Seven rats were randomly allocated to each group. The 50% mechanical withdrawal threshold of group 2.5 (after the administration of vitamin C) was higher than that of the control group and group 1.0 (P < 0.05). At 1 day of the administration of vitamin C, the 50% mechanical withdrawal threshold of group 1.0 was higher than that of the control group and the blood levels of TAS in groups 2.5 and 7.5 were higher than that in control group (P < 0.05). Twelve days after the administration of vitamin C, the blood levels of TAS in groups 2.5 and 7.5 were lower than that of the control group (P < 0.05). Discussion: The administration of a proper dose of vitamin C can reduce oxidative stress, increase antioxidants, and recover the threshold for mechanical allodynia in the CPIP model.

An alternative distal approach for the lumbar medial branch radiofrequency denervation: a prospective randomized comparative study.

BACKGROUND:An alternative technique involving a “distal approach” can be used for lumbar medial branch radiofrequency denervation (LMBRFD). We described and assessed this technique by comparing it with a conventional tunnel vision approach in a prospective randomized trial. METHODS:Eighty-two patients underwent LMBRFD by a distal (n = 41) or a tunnel vision approach (n = 41). The primary end point was a comparison of the mean difference in the change of 11-point numeric rating scale (NRS) scores of low back pain from entry to the scores at 1 month (NRS at baseline—NRS at 1 month) and at 6 months (NRS at baseline—NRS at 6 months) between the distal approach group and the tunnel vision approach group. The secondary end points were a change of NRS and the Oswestry disability index over time. RESULTS:Thirty-four patients in each group had complete time courses. There were no statistically significant differences in the change of NRS scores between the groups at 1 month (corrected P = 0.19; 97.5% 2-sided confidence interval [CI], −1.37 to 0.37) and 6 months (corrected P = 0.53; 97.5% CI, −1.36 to 0.77). Patients in both groups showed a statistically significant reduction in NRS and Oswestry disability index scores from baseline to that of the scores at 1 and 6 months (all P < 0.0001, Bonferroni corrected). The procedure-related pain score was significantly lower in the distal approach group (P = 0.001; 99% CI, −2.00 to −0.23). CONCLUSIONS:Patients who underwent LMBRFD by the tunnel vision or distal approaches showed significant pain relief at the 6-month follow-up. Less periprocedural pain was reported in the distal approach group. We consider that the distal approach provides an improved option for LMBRFD.

The neurological safety of epidural pamidronate in rats.

Background Pamidronate is a potent inhibitor of osteoclast-mediated bone resorption. Recently, the drug has been known to relieve bone pain. We hypothesized that direct epidural administration of pamidronate could have various advantages over oral administration with respect to dosage, side effects, and efficacy. Therefore, we evaluated the neuronal safety of epidurally-administered pamidronate. Methods Twenty-seven rats weighing 250-350 g were equally divided into 3 groups. Each group received an epidural administration with either 0.3 ml (3.75 mg) of pamidronate (group P), 0.3 ml of 40% alcohol (group A), or 0.3 ml of normal saline (group N). A Pinch-toe test, motor function evaluation, and histopathologic examination of the spinal cord to detect conditions such as chromatolysis, meningeal inflammation, and neuritis, were performed on the 2nd, 7th, and 21st day following administration of each drug. Results All rats in group A showed an abnormal response to the pinch-toe test and decreased motor function during the entire evaluation period. Abnormal histopathologic findings, including neuritis and meningeal inflammation were observed only in group A rats. Rats in group P, with the exception of 1, and group N showed no significant sensory/motor dysfunction over a 3-week observation period. No histopathologic changes were observed in groups P and N. Conclusions Direct epidural injection of pamidronate (about 12.5 mg/kg) showed no neurotoxic evidence in terms of sensory/motor function evaluation and histopathologic examination.