Postoperative pain relief by demand analgesia.

Postoperative pain relief is only apparently an easy task. A brief survey of literature investigating the discomfort experienced in the postoperative phase is all but encouraging. One can identify four basic problems in obtaining adequate results by delivery of analgesic drugs: a) the biological variability among individual patients, b) the unpredictable uptake of the drug administered intramuscularly, c) the time lag involved between request by the patient and the subsequent administration of a single dose and d) the lack of knowledge about the nature of the discomfort and its remedies. An alternative strategy introducing "On-Demand" analgesia administering prescribed doses at the right moment is presented and analysed a) as an operant conditioning process implementing a particular reinforcement schedule (behavioural sciences), as well as b) a negative feedback control loop that entrust the central judgement to the patient (system theory). Both approaches give insight into the results: the technique copes with biological variability; anticipating pain induced by fear disappears; the feedback strategy works well and patients adapt to a wide range in prescriptions; intermittent administration makes more efficient use of the analgesic; an optimal result is demonstrated in studies comparing on-demand analgesia with the normal IM-regime and epidural analgesia; continuity in pain relief can be obtained in routine clinical practice.

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.

Impact of laparoscopic surgery in the treatment of chronic abdominal pain syndrome

Chronic abdominal pain syndrome is becoming increasingly important with regard to the quality of life of the patients and its social and economic impact, in terms of cost of hospitalization, income loss due to sick leave, and pharmaceutical costs for treatments which fail to offer either significant clinical improvement or resolution of the pain symptoms. The main symptom is chronic abdominal pain, which may vary in intensity and may be associated with constipation and episodes of vomiting, when the clinical picture evolves toward one of subocclusion or total occlusion of the bowel. We considered the following criteria in our selection of patients for this study: 1) quality of life, 2) constant use of antispastic and analgesic medications, 3) absence of any other diagnosticable pathology prior to the operation. From August 1992 to April 2000 we operated on 105 patients with this syndrome (16 males and 89 females). Among these 8 patients had never been subjected to a laparotomy, while 97 had previously undergone surgical procedures (126 laparotomies). In the first 85 patients in the series (81%) we used a 10 mm laparoscope (0-30 degrees) to evaluate the presence of abdominal-visceral adhesions based on the type of surgery the patient had undergone previously, as well as the location of the pain reported by the patient. In 41 cases (48.2%) the pneumoperitoneum was obtained with the Veress needle. In another 44 cases (51.8%) the Hasson technique was used. Since June 1999, we have carried out the exploration of the abdominal cavity in 20 patients (19%) using a trocar and 2.2 mm laparoscope in the left hypochondrium along with a mini-trocar placed either in the right or left flank. (The positioning of the trocars depended on the previous surgical procedures performed). The exploration included inspection of the abdominal cavity. In 8 of the patients the procedure was carried out under local anaesthesia We performed laparoscopic adhesiolysis in 93 cases; in 7 cases no signs of adhesions were seen, while in another 5 cases it was necessary to convert the original laparoscopic procedure to a laparotomy. The types of adhesions found were fine-filmy (46%), dense-vascularised (46%), and cohesive (16%). In 6 cases during lysis of the adhesions complications of serous-muscular lesions occurred, which required laparotomic repair. In 5 cases we diagnosed a pathological condition which was not suspected. The average postoperative hospital stay was 2 days (range: 1-7); no major postoperative complications were noted. In the course of the follow-up of 78 patients over an average of 37 months (range: 6-72) the results obtained were as follows; 47 patients (60.2%) had complete pain relief, 18 patients (23.1%) had partial pain relief, and the remaining 13 patients (16.7%) had no significant pain relief. Laparoscopic exploration in patients with chronic abdominal pain is technically feasible in a simple manner in most patients. By means of careful and accurate preoperative selection of the patients partial if not complete pain relief can be achieved in a high percentage of cases (83.3% in our series).

External pedicular fixation of the lumbar spine: outcome evaluation by functional tests.

We analyzed the pain-relieving effect and the functional outcome during external pedicular fixation of the lumbar spine. Twenty patients were included, and the diagnoses were disc degeneration with or without facet joint arthrosis in eight patients, pain after decompression in six patients, spondylolysis/olisthesis in two patients, other types of lumbar anomalies in three patients, and pseudarthrosis after prior uninstrumented fusion in one patient. Before application of the external frame, the pain level on the Visual Analogue Scale was registered at rest, as a mean level for the preceding week, and at seven different functional tests. Maximum walking capacity and walking time needed for a standardized distance were also measured. The same test procedure was repeated 1 week postoperatively with the external frame applied in locked position. With stabilization, 11 patients reported pain relief at rest and 14 when approximating the mean pain level for the week. Both these measured levels correlated to the pain level at all of the seven functional tests. Thus, the patients selected for a subsequent fusion based on pain relief during extended functional provocation would not differ from the patients selected by using only the pain-relieving effect at rest. The patients reporting pain relief tended to increase their walking distance (p = 0.06, t test) but not the speed of walking.

Pharmacodynamic analysis of analgesic clinical trials: nonlinear mixed-effects logistic models.

In the development of an analgesic product, placebo-controlled clinical trials in patients with defined pain are used to study the dose-time-response relationship of the drug. In such trials, the response is usually an ordered categorical variable with longitudinal and subject-specific repeated measurements. The primary causal variables are time and analgesic concentration. The response may be informative right-hand censored because remedication with a known analgesic may be given if a patient has inadequate pain relief. Mixed-effects logistic models are used to estimate the probabilities of having certain pain relief or pain severity scores. A jackknife method is proposed to estimate the standard errors of parameter estimates. Posterior estimates of these probabilities, or of the scores themselves, allow the evaluation of efficacy for an analgesic. In this evaluation, therapeutic as well as statistical significance is assessed. Two case studies, one focusing on pain relief and the other on pain severity, are used to demonstrate the approach. The level of baseline pain appears to be a determinant of the pattern of response.

Switching opioids to transdermal fentanyl in a clinical setting

INTRODUCTION: The use of transdermal fentanyl is gaining in importance in the management of cancer pain. We describe the reasons for switching opioid medication to transdermal fentanyl in a pain management unit. METHODS: Case records of patients treated with transdermal fentanyl in our pain clinic were evaluated retrospectively. Conversion ratios were calculated from the opioid dosage before and after conversion. Pain intensities were assessed on a numeric rating scale (NRS 0: no pain, 10: worst pain imaginable). RESULTS: From October 1995 to December 1997 101 patients received transdermal fentanyl. Thirty-six patients had been treated with transdermal fentanyl before admission to our pain clinic, and relevant information was missing for one patient, so 64 patients were evaluated. Opioid therapy was switched to transdermal fentanyl during in-patient treatment for 53 patients and during out-patient treatment for 11 patients. Before conversion patients were treated with slow-release morphine (48%), immediate-release morphine (17%), buprenorphine (11%), tramadol (11%), levomethadone (5%), tilidine/naloxone (5%) and piritramid (3%). Reasons for opioid rotation were inadequate pain relief ( 33%), the patients' wish to reduce oral medication (20%), gastrointestinal side effects such as nausea (31%), vomiting (13%) and constipation (19%), dysphagia (27%) or others. Reduction of side effects was reported by 10 of 19 patients. In 12 of 21 patients, in whom the medication was switched because of inadequate pain relief, a reduction in pain intensity was reported. DISCUSSION: Conversion to transdermal therapy may readjust the balance between opioid analgesia and side effects. The opioid switch resulted in more pain relief or fewer side effects in half of the patients. A proposed equianalgesic conversion ratio between 70:1 and 100:1 from oral slow-release morphine to transdermal fentanyl can be confirmed by our data. Conversion rates from other opioids to transdermal fentanyl are suggested.

Percutaneous vertebroplasty--a new method for alleviation of back pain

Percutaneous vertebroplasty (PV) is an interventional radiological procedure for the treatment of pain in patients with vertebral compressions caused by osteoporosis, metastases or hemangioma. The method was introduced by Professors P Galibert and H Deramond at the University Hospital of Amiens, France in 1984. It consists of percutaneous injection of bone cement (polymethylmethacrylate) into the vertebral body under fluoroscopy guidance. PV has proved to be effective and safe. Permanent complete or partial pain relief is obtained within hours or days in more than 90% of cases. The complication rate is low, less than 3% for patients with osteoporosis and up to 10% in patients with metastases. We report on the first 17 patients (11 with osteoporosis, 3 with metastases and 3 with hemangiomas) treated in Sweden at the Department of Interventional Neuroradiology, Sahlgrenska Hospital, Goteborg University. We obtained complete pain relief in 71% and partial pain relief in 17% of cases. The majority of the patients improved in mobility and quality of life. We had no clinical complications.

Naloxone does not affect pain relief induced by electrical stimulation in man.

We wished to determine if pain relief that resulted from transcutaneous (TNS) or spinal cord electrical stimulation in patients with chronic pain was due to activation of an endogenous opiate-related pain control system. Naloxone (0.4-10 mg) or saline was injected in double-blind fashion intravenously into opiate-naive subjects with chronic pain who achieved 30% or greater pain relief with spinal cord stimulation (4 patients) or TNS (9 patients). Subjects rated their pain during stimulation and 2, 5, 10 and 15 min after the injection. Two days or more later the procedure was repeated using the alternate agent (naloxone or saline). Naloxone did not decrease the pain relief induced by stimulation, and therefore the effects of stimulation are probably not mediated by the endogenous opiates.

Decompressive lumbar laminectomy for spinal stenosis.

A total of 258 consecutive decompressive lumbar laminectomies performed on 244 individuals presenting with spinal stenosis were analyzed retrospectively. Spinal fusion was avoided in all but two patients. Outcome in terms of pain relief and return to normal activity was evaluated in two stages, one derived from patient charts and having a relatively short-term follow-up time (mean 8.4 months) and a second derived from patient responses to a questionnaire (which also scored for satisfaction with the results of surgery), which had a longer follow-up time (mean 4.7 years). More than 20 clinical and operative parameters were analyzed. Overall, a high degree of success (93% pain relief, 95% return to normal activity) was achieved in the short term, which was supported by the longer-term follow-up data (64% pain relief, 56% activity return, 75% satisfaction). The following factors were not significantly correlated with outcome: patient age; sex; worker's compensation or no-fault insurance status; employed versus not employed; a history of back surgery prior to the laminectomy studied; existence of degenerative spondylolisthesis or scoliosis; complete versus incomplete myelographic block; or the level of the lumbar spine undergoing surgery. The major conclusions arising from these data are: 1) for all age groups through at least the eighth decade of life, decompressive lumbar laminectomy is a relatively safe operation having a high medium-to-long-term success rate; 2) lumbar instability following laminectomy is rare, even in individuals presenting prior to surgery with degenerative instability conditions; and 3) lumbar fusion in addition to the decompressive laminectomy procedure is rarely required for degenerative spinal stenosis.

Are single fractions of radiotherapy suitable for plantar fasciitis?

The use of radiotherapy for plantar fasciitis has never been reported in Australasia and is scarcely found in the English language medical literature, but it is commonly used in Europe, especially in Germany. In Europe, treatment courses consisting of multiple small fractions have been associated with high levels of pain relief. In the present report, the use of single fractions or radiotherapy was evaluated by reviewing seven consecutive patients referred for treatment and by applying objective and subjective criteria for pain relief. One patient died of unrelated causes soon after treatment and one declined to receive radiotherapy. Four patients each received a single dose of 8 Gy resulting in complete pain relief. One patient was treated with 8 Gy and 12 weeks later was retreated achieving partial pain relief. A follow-up interview was conducted after a mean of 15.6 months, ranging from 1.5 to 30 months. No acute or late effects occurred; however, the possibility that delayed effects may yet occur, particularly carcinogenesis, cannot be excluded. Radiotherapy for this common condition should be investigated further as it might be safer and more effective than other methods currently in use.