Direct effect of electrical stimulation on peripheral nerve evoked activity: implications in pain relief.

Experiments were performed with a peripheral neurostimulator, used clinically for pain relief, on isolated cat cutaneous peripheral nerve to determine the effect of electrical stimulation on components of the compound action potential. The results show that neurostimulation alters the conduction velocity and the amplitude of both the A-alpha and beta and the A-delta waves with the more slowly-conducting A-delta component showing the greatest changes. This direct alteration of peripheral nerve activity distal to the first synapse in the spinal cord might contribute to the mechanism of pain relief.

Pitfalls of distal pancreatectomy for relief of pain in chronic pancreatitis.

PURPOSE: To examine whether preoperative computed tomography (CT) scans and pancreatograms can: (1) identify patients with chronic pancreatitis localized to the tail of the pancreas; and (2) select those patients who can obtain pain relief from a distal pancreatectomy. PATIENTS AND METHODS: Twenty patients were identified on whom the authors had performed distal pancreatectomy for relief of pain between January 1, 1991 and August 1, 1994. The results of surgery were classified as good, fair, or poor based on return to work and need for narcotics or rehospitalization. RESULTS: Eleven patients had good, 3 fair, and 6 poor results. All 7 patients with pseudocysts of the tail of the pancreas had good results, while 9 of 13 patients without pseudocysts had poor results. No other finding on CT scan, pancreatography, or laparotomy predicted successful pain relief by distal pancreatectomy. Furthermore, 3 patients had unexpected carcinoma found at the time of surgery. CONCLUSIONS: Even when anatomic evidence suggests that chronic pancreatitis primarily involves the tail of the pancreas and there is a stricture of the midpancreatic duct that is believed to cause the symptoms, distal pancreatectomy seldom provides sustained pain relief. Unsuspected carcinoma of the body and tail of the pancreas occurs frequently in this subset of patients with chronic pancreatitis.

An investigation into the use of aromatherapy in intrapartum midwifery practice.

OBJECTIVE: The principal aim of the study was to examine the contribution of aromatherapy to the promotion of maternal comfort during labor and as a tool to improve the quality of midwifery care. DESIGN: Evaluative study. SETTING: Delivery suite in a large British teaching hospital with approximately 6,500 deliveries per annum. SUBJECTS: A total of 8,058 mothers were evaluated between 1990 and 1998. INTERVENTIONS: Women were offered aromatherapy to relieve anxiety, pain, nausea and/or vomiting or to strengthen contractions. Routine data collected on the use of aromatherapy over the period were analyzed. Data from the unit audit were used to provide a comparison group of mothers not given aromatherapy (n = 15,799) from the study center. OUTCOME MEASURES: Outcome measures include mothers' ratings of effectiveness, outcomes of labor, use of pharmacologic pain relief, uptake of intravenous oxytocin, reported associated symptoms, and annual costs. RESULTS: The use of aromatherapy during childbirth was an increasingly popular care option with mothers and midwives. More than 50% of mothers rated it as helpful, and only 14% found it unhelpful. The use of aromatherapy was not confined to low-risk mothers. Sixty percent of the sample were primigravidae, and 32% overall had had their labor induced. The administration of aromatherapy in childbirth did appear to reduce the need for additional pain relief in a proportion of mothers. More than 8% of primigravidae and 18% of multigravidae used no conventional pain relief during labor after using essential oils. During the years of the study, the use of pethidine in the study center declined from 6% to 0.2% of women. The study also showed that aromatherapy may have the potential to augment labor contractions for women in dysfunctional labour. A very low number of associated adverse symptoms were reported (1%). CONCLUSION: This study represents a successful example of the integration of a complementary therapy into mainstream midwifery practice and forms a basis for future research.

The evaluation of the effectiveness of half-body irradiation as palliative treatment in patients with multiple bone metastases

The results of simplified method of hemibody irradiation of 23 patients with multiple painful bone metastases are presented. In all cases without proven bone metastases in skull and distal part of limbs, these parts of the body were excluded from irradiated field. The study comprised 25 cases of hemibody irradiation. The degree of pain relief and performance status improvement was assessed one and two months after treatment, depending on clinical and histopathological diagnosis and type of bone metastases. The best symptomatic results were obtained in the cases of multiple myelomas (100% of pain relief), prostate cancers (the average degree of 78%) and lung cancers (88%). Considering histopathological diagnosis, the best answer was found in multiple myeloma and squamous cell cancer (88%). Taking into account type of metastases the best result was obtained in the cases of osteolytic metastases (65%). No difference between upper and lower hemibody irradiation was found. The statistically significant correlation between pain relief, performance status improvement and decrease of analgetics use was found. The obtained results suggest that presented simplified form of hemibody irradiation is an effective symptomatic treatment modality in the cases with multiple painful bone metastases, giving an increase of life quality without significant radiation morbidity.

The role of radionuclide angiocardiography in the preoperative prediction of pain relief and prolonged survival following coronary artery bypass grafting.

Radionuclide angiocardiography (RNA) provides noninvasive measurements of left ventricular function during rest and exercise, which appear to reflect the magnitude of fibrosis and ischemia in patients with coronary artery disease. This investigation evaluated the usefulness of these measurements for providing prognostic information, useful in selecting therapy. The RNA study group included 278 patients with a low resting ejection fraction and coronary artery disease documented by angiography. Patients were followed for up to three years to define survival and incidence of complete pain relief. The 172 patients treated medically had less favorable survival and pain relief than the 106 surgically treated patients. In the medically treated patients, a positive RNA defined a subgroup of 113 patients, with a 20% lower 3-year survival than the 59 patients with a negative RNA. Moreover, comparison of patients receiving medical and surgical therapy following a positive RNA documented a clear improvement in both survival and pain relief for those who showed significant ischemia during exercise and subsequently underwent coronary bypass procedures. In patients with a negative RNA, medical and surgical therapy resulted in a similar survival rate and little difference in pain relief. Calculations comparing the maximal potential increase in survival and complete pain relief, using multiple criteria known to provide prognostic information, identified the exercise response on RNA as the single most important variable for selection of therapy. Therefore, the left ventricular response to exercise provides important prognostic information in patients with low resting ejection fractions, and the results of this procedure can be used to define subgroups of patients who will and will not benefit from coronary artery bypass grafting.

Postobstructive chronic pancreatitis: results with distal resection.

HYPOTHESIS: For most patients with chronic obstructive pancreatitis, distal pancreatectomy confers pain relief. DESIGN: Retrospective case series. Follow-up was complete in 80% of study subjects (mean follow-up, 6.7 years). SETTING: Tertiary care center. PATIENTS: Among 484 patients with chronic pancreatitis undergoing operation from 1976 to 1997, 40 with postobstructive chronic pancreatitis were identified. Criteria for selection included an isolated, dominant major pancreatic duct stricture or cutoff, changes of chronic pancreatitis in the distal pancreas, and ostensibly normal parenchyma without calcification in the proximal gland. The patients were reviewed with regard to operative procedure, postoperative course, and outcome. MAIN OUTCOME MEASURES: Outcome measures included degree of pain relief, morbidity and mortality of operation, survival, rates of endocrine and exocrine insufficiency, and ability to return to work and/or normal activities. RESULTS: All but 1 of the 40 patients had abdominal pain, and 20 (50%) had recurrent episodes of acute pancreatitis. Suspicion of malignancy was a concern in 16 patients (40%). Thirty-eight patients underwent distal pancreatectomy; 1 had a central resection and another a Roux-en-Y cystojejunostomy. There was no operative mortality, but significant morbidity occurred in 15%. Among 31 patients with preoperative pain in whom long-term follow-up was available, complete or significant pain relief was achieved in 25 (81%); 74% returned to normal social function, but about half had some element of pancreatic insufficiency. CONCLUSIONS: Distal pancreatectomy is a safe procedure and achieves pain relief and good quality of life in a large percentage of patients (80%) with presumed postobstructive chronic pancreatitis. However, some of these patients with chronic pancreatitis involving the entire gland have disease masquerading as postobstructive chronic pancreatitis secondary to an ostensibly isolated dominant pancreatic ductal stricture.

The pituitary as a target of antalgic treatment of chronic cancer pain: a possible mechanism of pain relief through pituitary neuroadenolysis.

Surgical hypophysectomy performed in 18 cases with hormone-dependent carcinoma resulted in tumour regression in 38.8% of the cases, and pain relief in 88%. Neuroadenolysis performed 170 times on 130 cases resulted in pain relief in 94% with hormone-dependent carcinoma, and 70% with non-dependent carcinoma. The clinical investigations, following performance of neuroadenolysis, indicate suppressed pituitary function, significant increase of ACTH, thyrotropin-releasing hormone and vasopressin in the cerebrospinal fluid (CSF), delay of long latencies in somatosensory evoked potential and increased pain threshold of C-fibres. Increase of beta-endorphin in CSF was very brief. Though the exact physiological activity in pain sensation of those peptides other than endorphins still remains obscure, increase of the peptides which are mainly synthesized in the hypothalamopituitary axis, along with suppressed pituitary function, is considered to exert a long-lasting suppressive effect on the mediation and perception of cancer pain through C-fibres and the central nervous system.

The effect of peripheral glycerol on trigeminal neuropathic pain examined by quantitative assessment of abnormal pain and sensory perception.

In nine patients with trigeminal neuropathic pain after nerve injury, we examined prospectively the effect of peripheral glycerol neurolysis on abnormal pain and sensory perception. In the painful facial skin area of these patients, we found increased temperature and tactile thresholds and the presence of abnormal temporal summation of pain. In seven patients, neuropathic pain was peripheral and disappeared after application of local anaesthesia at or proximal to the site of nerve injury. Neuropathic pain was central in two patients, and unresponsive to local anaesthesia applied proximal to the site of nerve injury. Six weeks after injection of glycerol proximal to the site of nerve injury, no or marginal pain relief was found in 8 patients with peripheral or central trigeminal neuropathic pain. On the other hand, in one of the patients with peripheral trigeminal neuropathic pain, glycerol was given at the site of nerve injury, and produced total pain relief for the whole observation period of 7 months. In this patient, pain relief was associated with normalisation of abnormal temporal summation of pain, which was not observed in the 8 patients with no or marginal pain relief. No further changes in temperature or tactile thresholds were found in any of the 9 patients after a single injection of absolute glycerol. Total pain relief in one of the patients probably is related to the ability of glycerol to inhibit ongoing ectopic impulse generation at the site of nerve injury. We suggest that glycerol-induced reduction of primary afferent hyperactivity may secondarily result in down-regulation of central neuronal hyperexcitability. The efficacy of application of glycerol at the site of nerve injury in patients with peripheral trigeminal neuropathic pain may warrant further investigation. However, this prospective study does not provide evidence that application of glycerol proximal to the site of nerve injury has a place in the treatment of trigeminal neuropathic pain.

Spinal cord stimulation in critical limb ischemia of the lower extremities: our experience.

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 specific prognostic parameters in the prediction of successful SCS and to perform a retrospective data analysis obtained during our patient follow-up. METHODS: 150 patients (97 men, 53 women; mean age: 68 years; range: 46-81) were submitted to implantation of a spinal cord electrical generator for rest pain, and trophic lesions with dry gangrene in severe lower limb ischemia, after failed conservative or surgical treatment. The clinical status was classified as Fontaine's stage III and IV and the main pathology was essentially due to atherosclerosis and diabetic vascular disease. In clinical controls, pedal transcutaneous oxygen tension (TcPO2), ankle and toe pressure Doppler measurements were utilised to select and follow-up the patients. RESULTS: After a mean follow-up of 71 months (range 24-138), pain relief >75% and limb salvage was achieved in 85 patients. In 28 patients was obtained a partial success with pain relief >50% and limb salvage for at least 6 months, while in 37 patients the method failed or for technical problems the device was removed, and the patients were amputated. TcPO2 was assessed on the dorsum of the foot. Clinical improvement and SCS success was associated with the increasing of TcPO2, before and after implantation (temporary period). Limb salvage was achieved in the patients that presented significant TcPO2 changes within the first 2 weeks of the testing period, indifferent from the stage of the disease, and from the initial TcPO2 value. After long-term patient follow-up TcPO2 changes, from 22.6 to 43.1 mm Hg in these with rest pain (p<0.01), from 16.2 to 36.1 mmHg (p<0.02) in those with trophic lesions <3 cm2, and from 12.4 to 28.1 in the patients with trophic lesions >3 cm2. A TcPO2 increase of more than 50% in the first 2 months after implantation was predictive of success, and was related with the presence of adequate paresthesias 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 be proven an excellent alternative therapy that improves the quality of life. TcPO2 changes, within a test period of 2 weeks, is a predictive index of therapy success and should be considered before the final decision in terms of cost effect, for the permanent implantation.

Risk factors of inadequate pain relief during epidural analgesia for labour and delivery.

PURPOSE: To determine the causes of failure of epidural analgesia during labour and delivery. METHODS: During six months, pregnant patients receiving epidural analgesia and delivering vaginally were studied prospectively. Bupivacaine 0.125% was used for the initial bolus dose and subsequent continuous infusion. Top-ups of the same solution were used for inadequate pain relief assessed using a visual analogue pain score (VAPS) and/or by clinical examination. Inadequate pain relief was defined as the need for > or = 2 top-ups in addition to epidural infusion and failure during delivery as VAPS > or = 30 mm during the expulsion phase. RESULTS: 1009 patients delivered during this period, 596 had epidural analgesia for vaginal delivery of a live infant and data were complete in 456. Inadequate pain relief during labour and during delivery were found in 5.3% and 19.7% of patients. Risk factors of inadequate pain relief included: inadequate analgesic efficacy of the first dose (Odds ratio: 3.5, P = 0.001) and posterior presentation (Odds ratio: 5.6, P = 0.001). Radicular pain during epidural placement was associated with failure during labour (Odds ratio: 3.9, P = 0.05). Duration of epidural analgesia > six hours (Odds ratio: 9.1, P = 0.001) was a risk factor for insufficient pain relief during labour whereas duration of epidural analgesia < one hour was associated with pain during delivery (Odds ratio: 18.3, P = 0.001). CONCLUSION: Several obstetrical and epidural-related factors increase the risk of inadequate epidural analgesia. For some, simple changes of practice pattern may lead to improved pain relief.