Biochemistry of pain relief with intracerebral stimulation. Few facts and many hypotheses.

On the basis of data obtained from subprimates subjected to acute pain stimuli, it has been hypothesized that the suppression of chronic pain in man during stimulation in the periventricular region involves endogenous opioid mechanisms. However, there is at present no direct and unequivocal proof that the pain relief in man is necessarily and entirely dependent upon such mechanisms. There exist several putative substances with opiate-like properties but they are difficult to identify. The assay methods lack specificity and cross-reactions are common. There are only a few studies published on the influence of intracerebral stimulation in man on the CSF-content of opioid substances; the changes observed are inconsistent, and data are only given on patients having satisfactory pain relief. Furthermore, measurements have been made only during the course of a few hours and nothing is reported on the relationship between the changing concentrations of the substance and the level of pain. The observation that Naloxone may reverse the effect of intracerebral stimulation has become the keystone in postulating common mechanisms for stimulation-produced pain relief and morphine analgesia. The fact, that Naloxone is sometime ineffective or has to be used in huge, and unphysiological, doses is generally disregarded. There are a number of substances which may serve as neurotransmittors in pain transmission and pain inhibition but their mode of action in the generation and suppression of chronic pain is entirely unknown. Data collected from various European clinics covering more than 200 patients subjected to intracerebral stimulation show that the outcome of this treatment is highly unpredictable. Intracerebral stimulation as a clinically useful treatment of chronic pain can not be further developed unless hard data on its biochemical background in man are provided.

Effectiveness of hypofractionated radiotherapy in painful bone metastases. Two prospective studies with 1 x 4 Gy and 4 x 4 Gy.

BACKGROUND: Although effectiveness of fractionated radiotherapy for painful bone metastases is well documented, there are unanswered questions regarding the adequacy of low-dose short radiation schedules for long-term pain control which give maximum benefit in patients with a short life expectancy. PATIENTS AND METHODS: Two consecutive non-randomized prospective follow-up studies were performed at a single institution to analyze pain response and duration of response in patients with a variety of primary tumors. Included were only patients with symptomatic nonvertebral bone metastases and without impending pathologic fracture. Forty-five patients received 1 x 4 Gy to 50 different sites (group I) while 86 patients received 4 x 4 Gy to 96 sites (group II). pain relief to irradiation was evaluated according to patient interviews using a 4-point categorical scale. Follow-up was performed 7 and 90 days after radiotherapy. RESULTS: pain relief after 4 x 4 Gy was significantly superior to 1 x 4 Gy with pain control rates being 86.5% vs 48% at day 7 (after end of treatment) and 80% vs 55% at day 90, respectively. A subgroup analysis of patients treated with 4 x 4 Gy demonstrated a more favorable outcome for breast cancer patients in comparison to patients with other primaries concerning pain relief (96% vs 81%), pain control after 90 days (93% vs 72%), median time to pain progression (9 vs 3 months), and median overall survival (14 vs 5.5 months). CONCLUSIONS: In this study 4 x 4 Gy proved to be clearly superior to 1 x 4 Gy in relieving pain from symptomatic nonvertebral bone metastases without impending pathologic fracture. Even if radiotherapy with 1 single fraction seems to be applicable in specific cases doses higher than 4 Gy should be chosen. In breast cancer patients pain control seems to be better compared to other primaries.

pain relief following tennis elbow release.

We studied the outcome of tennis elbow release in 27 patients at an average of 29.6 months after surgery. We found that 44% of patients had obtained complete pain relief, 37% of patients experienced occasional pain and 19% of patients still experienced moderate pain. pain relief was significantly better in those patients with the shorter duration of preoperative symptoms. We therefore conclude that surgery for tennis elbow should be employed at an earlier stage than is currently practised.

Effective bone palliation as related to various treatment regimens.

Various dose-time treatment plans have been used to obtain long duration pain relief in patients with metastatic bone disease. Very little has appeared in the literature evaluating the relationship of dose and fractionation to initial, delayed and permanent bone pain relief. At the Swedish Hospital Tumor Institute, 152 treatment fields in 110 patients were evaluated, with a clinical follow-up in many of over five years. Those treated at lower total doses with less fractionation achieved the same quality and duration of pain relief as higher doses. Treatment plans also were compared using the Ellis method of nominal standard dose.

Non-oncologic chronic pain relief with opioids

Opioids for non cancer pain control are controversial. The evaluation of the pain relief, changes in quality of life and complications due to long term infusion of opioids in the lumbar subarachnoid space in 11 patients with non cancer pain were the goals of this study. Patients were previously treated with drugs and surgical procedures, without significant pain relief. Patients were asked to compare pain characteristics and daily life activities before and after this treatment. The long term spinal opioids through implantable pumps for non-oncologic pain produced pain relief but did not improve the quality of life in the majority of the cases.

Palliative radiotherapy for bone pain in hormone refractory prostate cancer

From 1970 to 1992, 23 patients were treated with irradiation for palliation of pain caused by bone metastases from hormone refractory adenocarcinoma of the prostate at Cancer Institute Hospital. External beam irradiation was delivered to painful bony metastatic sites using linear accelerator. Numbers of irradiated sites were 1, 2, 3 in 6 patients, 4 in 3 patients and 5 or 7 in one patient. To evaluate the pain relief at the irradiated sites, severity and frequency of pain were measured quantitatively before and 1 month after the treatment. Overall efficacy of palliation was evaluated by summing up results of the irradiated sites in each patient. pain relief was obtained in all the irradiated sites. Minimal relief, partial relief and complete relief of pain were achieved in 10%, 15% and 75% of the 60 irradiated sites, respectively. No significant dose-response relationship was observed. Complete pain relief was attained less frequently at the sites with severe and constant pain that those with moderate and intermittent pain. Minimal, partial and complete palliation of pain was attained in 9%, 17% and 74% of 23 patients, respectively. In patients with highly extensive bone metastases, many irradiated sites, or many irradiated bones, complete palliation was difficult to obtain. Recurrence of pain was observed in one site. In other 59 irradiated sites, pain relief lasted until patient's death or throughout the follow-up period (maximum 51 months, median 9 months). We concluded that external beam irradiation is an effective palliation therapy for pain of bone metastases from hormone refractory prostate cancer and will play a considerable role in the management of advanced disease.

Superior hypogastric plexus block for chronic pelvic pain in the presence of endometriosis: CT techniques and results.

PURPOSE: To evaluate the use of superior hypogastric plexus block with computed tomographic (CT) guidance in patients with endometriosis and chronic pelvic pain. MATERIALS AND METHODS: Seven blocks were performed on an outpatient basis in five women with endometriosis and pelvic pain. In the first four patients, one or two 20-gauge, 15-cm needles were placed anterior to the spine at the common iliac bifurcation from a posterior approach. In the fifth patient, the block was performed from an anterior approach with a single needle. RESULTS: One procedure resulted in mild pain relief, three in considerable pain relief, one in complete midline pain relief with no change in the lateral pain, and one in complete pain relief. One procedure was terminated because anesthetic was injected into the peritoneal cavity. There were no other complications. CONCLUSION: CT-guided superior hypogastric plexus block is easily performed and can be used to assess whether chronic pelvic pain can be attenuated by blocking the superior hypogastric plexus.

Radiosurgical treatment of trigeminal neuralgia: evaluating quality of life and treatment outcomes.

PURPOSE: To assess the safety, efficacy, and quality of life (QOL) associated with radiosurgical treatment for trigeminal neuralgia (TN). METHODS AND MATERIALS: Between June 1996 and June 2001, 112 patients with TN refractory to medical or surgical management were treated with gamma knife radiosurgery (GKRS) at the University of Maryland Medical Center. A median prescription dose of 75 Gy (range: 70-80 Gy) was delivered to the involved trigeminal nerve root entry zone. Treatment outcomes were assessed through patient self-reports of pain control and medication usage during follow-up visits. In addition, patients responded to a standard questionnaire containing the Barrow Neurologic Institute Pain Scale (BNI) and selected sections of the McGill Pain Scale. Treatment outcomes and objective quality of life measures were also addressed. RESULTS: Ninety-six patients (86%) completed questionnaires for a median follow-up of 30 months (range: 8-66 months). Seventy-four patients (77%) reported pain relief occurring after a median of 3 weeks (range: 0-24 weeks) after GKRS. A decrease in medication usage was noted in 66% of patients. Actuarial analysis demonstrated 1-year, 2-year, and 3-year recurrence rates of 23%, 33%, and 39%, respectively. Response to treatment was associated with lack of prior surgical treatment (p = 0.03) and less than 50 months' pain duration before GKRS (p = 0.04). Patients who described their TN pain as more severe than their worst non-TN headache pain (McGill Pain Scale IV-V vs. I-III) were also more likely to respond to treatment (p < 0.001). Seven (7.3%) patients reported new or increased trigeminal dysfunction; however, only 3.1% reported these symptoms as bothersome (BNI III-IV). Patients with sustained pain relief reported an average of 100% improvement in their QOL as a direct result of pain relief after GKRS, and 100% believed that the procedure was successful. Furthermore, among those patients with temporary pain relief and subsequent recurrence, 65% felt their treatment was a success with an average of 80% improvement in their QOL. CONCLUSIONS: GKRS provides significant pain relief and improves QOL in the majority of patients treated for TN, with few bothersome side effects. Patients with both temporary and sustained responses to treatment realized significant improvements in QOL after GKRS, and considered their treatment successful. Longer follow-up of these patients may reveal additional recurrences highlighting the importance of studies evaluating repeat GKRS and optimization of current treatment techniques and patient selection.

Outcomes for surgical management of orchalgia in patients with identifiable intrascrotal lesions.

OBJECTIVE: The outcome of surgery for relief of orchalgia in patients with identifiable intrascrotal pathology is not well defined. We evaluated the success of commonly performed surgical procedure indicated for pain relief in patients with specific intrascrotal lesions. METHODS: Surgical cases performed for relief of painful scrotal pathology were reviewed, including ligation of internal spermatic vein, hydrocelectomy, spermatocelectomy, and orchiopexy for suspected intermittent torsion. Relief of pain as reported to the physician and time for return to full activity were determined. pain relief was compared to a 50% placebo rate using Fisher's exact test. RESULTS: Eigthy-five of 151 patients (56%) undergoing surgery for pain relief had complete data and adequate follow-up for analysis. Of 40 patients who had ligation of the internal spermatic vein, 30 (75%) were relieved of pain (p = 0.037). All 19 patients with painful hydroceles and 16 of 17 (94%) with spermatoceles were relieved of pain (p < 0.001). Of 9 patients undergoing scrotal orchiopexy for suspected intermittent torsion, 8 (89%) were pain-free (p < 0.001). CONCLUSION: Surgical management of specific intrascrotal lesions is highly effective.

Factort of vaso-occlusive pain in children with sickle cell disease.

PURPOSE: A descriptive, longitudinal design was used to evaluate the pain management strategies used in children with sickle cell disease who were experiencing pain during a vaso-occlusive episode. METHODS: A list of the medications (name, amount, mode of delivery, and frequency) prescribed and administered for pain management for each participant was recorded on the Medication Quantification Scale Worksheet, starting from day 1 of hospitalization to the day of discharge. Children were asked once each evening to provide three separate ratings of how much the pain medication helped them during the day, evening, and night using a 0-to-10 rating scale. RESULTS: Using patient-controlled analgesia (PCA), children self-administered only 35% of the analgesic medications that were prescribed and reported little pain relief. No significant relationships were found between changes in pain relief scores and the amount of analgesics administered. CONCLUSIONS: Clinicians need to monitor the amount of analgesics delivered in relationship to pain relief and assist children to titrate PCA administration of analgesics to achieve optimal pain control, or to advocate for changes in the PCA regimen when children cannot assume control of pain management.