Cervical nerve root blocks: indications and role of MR imaging.

PURPOSE: To examine whether magnetic resonance (MR) imaging findings of the cervical spine can predict pain relief after selective computed tomography (CT)-guided nerve root block and thus assist in the appropriate selection of patients who are suitable for this procedure. MATERIALS AND METHODS: Sixty consecutive patients with cervical radicular pain were examined with MR imaging and then treated with CT-guided cervical nerve root blocks (CNRBs). Various MR imaging findings were assessed and compared in terms of associated pain relief after CNRB. pain relief was graded (0%-100%) by using a visual analogue scale (VAS). The relationship between MR imaging findings and level of pain relief was tested by using Mann-Whitney U and Kruskal-Wallis tests. RESULTS: The mean percentage of pain reduction at VAS grading was 46%. There was a significant relationship between pain relief level and both location of disk herniation (mean pain reductions of 41% at median or mediolateral locations and 64% at foraminal locations, P =.034) and location of nerve root compromise (mean pain reductions of 19% at intraspinal, 45% at foraminal entrance, and 58% at foraminal locations; P =.019). There was an inverse relationship between pain relief level and absence or presence of spinal canal stenosis (mean pain reductions of 29% when stenosis present and 53% when stenosis absent, P =.013). Other parameters were not significantly related to pain relief. CONCLUSION: MR imaging of the cervical spine assists in the appropriate selection of patients suitable for CNRB. Patients with foraminal disk herniation, foraminal nerve root compromise, and no spinal canal stenosis appear to have the greatest pain relief after this procedure. Copyright RSNA, 2004

The effect of patient age, gender, and tibial component fixation on pain relief after cementless total knee arthroplasty.

Cementless total knee arthroplasties (TKAs) were prospectively evaluated for pain relief in 1110 knees. The effect of screws in the tibial component, the age of the patients, and the gender of the patients were studied to determine the effect of these parameters on pain relief one and two years postsurgery. The group with screws in the tibial component (Ortholoc II) had a significantly higher percentage of pain-free knees at one year than at two years postsurgery, and the older patients had a significantly higher rate of pain-free knees at one- and two years postsurgery than the younger patients. Older female patients with Ortholoc I TKAs had a significantly higher percentage of pain-free knees than did older male patients at one-year postsurgery, but not at two years. The group with screws in the tibial components (Ortholoc II) had a higher percentage of pain-free knees at one-year postsurgery than did the Ortholoc I knees, but there was no difference between Ortholoc I and II at two-years postsurgery. In the Ortholoc II group, there was also no difference in results among sexes or between patients older and younger than 65 years old. The correlation coefficient was calculated to evaluate the relationship between body weight and the degree of pain after TKA. No significant correlation could be found at one and two years after surgery.

Transcutaneous oxygen tension (TcPO2) in the testing period of spinal cord stimulation (SCS) in critical limb ischemia of the lower extremities.

BACKGROUND: Spinal cord stimulation (SCS) improves microcirculatory blood flow, relieves ischemic pain and reduces amputation rate in patients with severe peripheral arterial occlusive disease. AIM: To evaluate the transcutaneous oxygen tension (TcPO2) measurements as a specific prognostic parameter in the prediction for permanent device implantation in a prospective controlled study in patients with lower limb ischemia. METHODS: 45 patients (35 men, 10 women; mean age 65 years, range: 46-70 years) were submitted to implantation of a spinal cord electrical generator for rest pain, trophic lesions dry gangrene in severe lower limb ischemia, after failed conservative or surgical treatment. The clinical status was classified as Fontaine's stages III and IV and the main pathology was essentially due to atherosclerosis and diabetic vascular disease. Pedal transcutaneous oxygen tension (TcPO2), ankle and toe pressure Doppler measurements were performed before, 2 weeks and 4 weeks after implantation. RESULTS: After 18 months follow-up, pain relief was > 75% and limb salvage was achieved in 26 patients. In 9 patients, a partial success with pain relief > 50% and limb salvage was obtained for at least 6 months. In 10 patients, the method failed, and the patients' limbs were amputated. TcPO2 was assessed on the dorsum of the foot. Clinical improvement and SCS success was associated with an increase of TcPO2, within the first 2 weeks after implantation (temporary period). Limb salvage was achieved in those patients who presented significant TcPO2 increase within the first 2 weeks of the testing period (from 21.6 mmHg to 29.5 mmHg in the patients with rest pain, P = 0.035, from 15.2 mmHg to 21.1 mmHg, P = 0.035 in those with trophic lesions < 3 cm2, and in those with trophic lesions > 3 cm2, from 12.4 mmHg to 17.3 mmHg) independently of the stage of the disease and of the initial TcPO2 value. TcPO2 changes were related to the presence of adequate paresthesias and warmth in the painful area during the trial period. The systolic ankle/brachial blood pressure index did not change under stimulation. CONCLUSIONS: In patients with failed conservative and surgical treatment for severe critical lower limb ischemia, the SCS increases the skin blood flow, is associated with a significant pain relief and could prove an excellent alternative therapy that improves the quality of life. We also demonstrate that TcPO2 increase within a test period of 2 weeks, is a predictive index of SCS therapy success and should be considered in terms of cost effect before the final decision for permanent implantation.

Thalamic field potentials in chronic central pain treated by periventricular gray stimulation -- a series of eight cases.

Chronic deep brain stimulation (DBS) of the periventricular gray (PVG) has been used for the treatment of chronic central pain for decades. In recent years motor cortex stimulation (MCS) has largely supplanted DBS in the surgical management of intractable neuropathic pain of central origin. However, MCS provides satisfactory pain relief in about 50-75% of cases, a range comparable to that reported for DBS (none of the reports are in placebo-controlled studies and hence the further need for caution in evaluating and comparing these results). Our experience also suggests that there is still a role for DBS in the control of central pain. Here we present a series of eight consecutive cases of intractable chronic pain of central origin treated with PVG DBS with an average follow-up of 9 months.In each case, two electrodes were implanted in the PVG and the ventroposterolateral thalamic nucleus, respectively, under guidance of corneal topography/magnetic resonance imaging image fusion. The PVG was stimulated in the frequency range of 2-100 Hz in alert patients while pain was assessed using the McGill-Melzack visual analogue scale. In addition, local field potentials (FPs) were recorded from the sensory thalamus during PVG stimulation.Maximum pain relief was obtained with 5-35 Hz stimulation while 50-100 Hz made the pain worse. This suggests that pain suppression was frequency dependent. Interestingly, we detected low frequency thalamic FPs at 0.2-0.4 Hz closely associated with the pain. During 5-35 Hz PVG stimulation the amplitude of this potential was significantly reduced and this was associated with marked pain relief. At the higher frequencies (50-100 Hz), however, there was no reduction in the FPs and no pain suppression.We have found an interesting and consistent correlation between thalamic electrical activity and chronic pain. This low frequency potential may provide an objective index for quantifying chronic pain, and may hold further clues to the mechanism of action of PVG stimulation. It may be possible to use the presence of these slow FPs and the effect of trial PVG DBS on both the clinical status and the FPs to predict the probable success of future pain control in individual patients.

Incidence of prolonged pain relief following acupuncture.

From March 1973 to Decenber 1974, 2090 electroacupuncture treatments were applied to 533 patients with chronic pain. Of 533 patients, 276 (52%) reported excellent (greater than 75%) pain relief immediately after the last treatment, and 103 (19.3%) still reported excellent pain relief on a 4-week followup questionnaire. In March 1975, the authors contacted 87 of these 103 patients. Sixty-three reported that they still had excellent pain relief 3 to 18 months after therapy, 3 patients reported that their pain still was relieved 50%, and 21 patients said their pain had returned to the same intensity as before therapy. Thus, 12% of 533 patients who received acupuncture treatment for chronic pain had a significant degree of pain relief at least 3 months after therapy.

A statistical model for pain in patient-controlled analgesia and conventional intramuscular opioid regimens.

A statistical model was developed: 1) to compare the efficacy of patient-controlled analgesia (PCA) and traditional intramuscular (IM) opioids for pain relief in 40 patients after total knee replacement and, 2) to evaluate pain cycles associated with each technique. Hourly visual analog pain scores were subjected to two-way analysis of variance (ANOVA) and time-series analysis. Hourly verbal analog pain scores were used to determine predominant pain levels. According to ANOVA, PCA was no more effective than were IM opioids. Time-series analyses documented a complete cycle of pain every 5.3 hours in patients receiving IM opioids but no pain cycle with use of PCA. Analysis of PCA verbal analog scores demonstrated self-administration of opioids to "moderate" levels of pain relief with use of PCA, not to complete analgesia. These results suggest that certain patients may not envision complete postoperative analgesia as being possible. Hence, they self-administer opioids for pain relief with PCA according to their expectations. Population characteristics may modify PCA efficacy. These characteristics should be delineated and the use of PCA targeted to appropriate patients.

Cryohypophysectomy for the relief of pain in malignant disease.

Fifty consecutive patients with metastatic carcinoma who underwent cryohypophysectomy were studied. Of these, 26 had breast cancer, 19 had prostatic cancer, one had malignant melanoma, one had cancer of the kidney, and three had metastatic adenocarcinoma from an unknown primary tumour. After cryohypophysectomy, excellent pain relief was obtained in 48% of patients, good or acceptable pain relief was obtained in 40%, and poor or no relief in 12%. Two patients died: one of aspiration pneumonia and one of an unknown cerebral cause. Sixteen patients developed diabetes insipidus, of whom three required therapy with vasopressin; eight patients developed a cerebrospinal fluid leak, two of whom required surgical repair; and four patients developed meningitis, which resolved in three after antibiotic therapy. Results are compared with those from other published reports. pain relief from cryohypophysectomy is surmised to be due to the production of endorphins, but no proof of this is available.

Cost analysis of a mucoadhesive foam versus conventional treatment for postepisiotomy patients.

The cost of treating postepisiotomy pain and edema with foam containing 1% hydrocortisone acetate and 1% pramoxine hydrochloride and a spray with 20% benzocaine was compared in 200 postpartum patients. Treatment with foam was demonstrated to be more effective than benzocaine spray with greater pain relief and reduction of edema as shown by lower patient need of supplemental pain-relief measures. Treatment with foam was also determined to be less expensive than benzocaine spray when the cost of the supplemental pain-relief measures for benzocaine-treated patients were assessed. Methods used to determine actual hospital costs are presented, and supplemental pain relief treatments are discussed. Use of this type of cost analysis may be useful to the P & T Committee when determining actual cost-effectiveness of different treatment modalities.

Postoperative pain relief and hospital stay after total esophagectomy.

Intraoperative and postsurgical epidurally administered pain relief is associated with reduced morbidity. We reviewed the charts of 19 patients who had total esophagectomy to see whether the method of postoperative pain relief influenced the length of hospital stay and cost of the procedure. The patients received either intravenous (group M) or epidural (group E) morphine for postoperative pain. The length of stay in the intensive care unit was reduced by 2 1/2 days and total hospital stay by 7 days in the epidural group. This resulted in a saving of Canadian $12,770 per patient.

Diagnostic epidural opioid technique.

Diagnostic epidural blocks were performed on 27 chronic pain patients sequentially using saline, fentanyl, and lidocaine solution. The patients were divided into one of four groups based on their response to the epidural solutions: placebo response group--pain relief with placebo solutions; fentanyl response group--pain relief with epidural fentanyl; lidocaine response group (LRG)--pain relief with lidocaine but not fentanyl; and no response group--no pain relief with any of the solutions used. The four groups were compared on the basis of age, sex, site of pain, duration of pain, narcotic use, pain assessment index, and workmen's compensation claims. The comparisons resulted in the conclusion that LRG patients had a much longer average duration of pain than the other groups. On the basis of the information gathered, it was theorized that, despite their response to epidural lidocaine, LRG patients may actually be a group of operant pain patients. Their failure to receive analgesia from epidural fentanyl may be a learned response such that they associate any sensory input from the affected area as painful. If follow-up studies support these findings, then the diagnostic opioid technique may be a more sensitive tool in diagnosing chronic pain.