Analgesic efficacy and bioavailability of ketorolac in postoperative pain: a probability analysis.

BACKGROUND: The analgesic efficacy and bioavailability of 30 mg intramuscular ketorolac was studied in 24 patients with severe or very severe postoperative pain. METHODS: Pain and pain relief were determined by a five-point verbal rating scale and data were submitted to a probability analysis. Ketorolac plasma levels were determined by high-performance liquid chromatography. RESULTS: Two patients chose not to finish the study; 22 patients completed the study achieving at least good pain relief. Of these 22 patients, 13 reached complete pain relief. Ketorolac was rapidly absorbed. Notwithstanding, pain relief increased gradually, showing considerable delay with regard to plasma concentrations. Analysis of the probability-time curves revealed that 25% of the patients obtained moderate pain relief at 7 min after ketorolac administration, 50% at 11 min, 75% at 29 min, and 95% at 60 min. Good pain relief was achieved in 25, 50, and 75% of the patients at 1.1, 1.8, and 2.7 h, respectively. Complete pain relief was achieved in 25% and 50% of the patients at 2.6 h and 3.7 h, respectively. The probability of exhibiting an acceptable pain relief in responsive patients for more than 5 h was 0.97. No serious side effects were detected. CONCLUSIONS: Results show that 30 mg intramuscular ketorolac is an adequate treatment for postoperative pain in the Mexican population. Therefore, the use of higher doses is not justified. Due to gradual installation of analgesia, administration of additional analgesic medication before 1 h is not recommended.

Treatment of deafferentation pain by chronic stimulation of the motor cortex: report of a series of 20 cases.

Twenty patients with deafferentation pain were treated by chronic stimulation of the motor cortex. The central fissure was localized using stereotactic MRI and the motor cortex was mapped using intra-operative somatosensory evoked potentials. Seven patients with trigeminal neuropathic pain experienced definite pain relief varying between 40 and 100%. Ten patients had central pain secondary to central nervous system lesions. A satisfactory long-lasting pain control (pain relief > 40%) was obtained in five of them (50% of cases). One patient with pain from peripheral nerve injury obtained more than 80% pain relief. Two patients had pain from spinal cord lesions. One did not respond but the other obtained an excellent long-term result. The location of the effective stimulation plots was in agreement with the somatotopic maps of the primary motor cortex. One patient developed a small extradural haematoma which resolved spontaneously. None of the patients developed seizure activity. This study confirms the potential value of motor cortex stimulation in the treatment of certain forms of intractable pain, especially in cases with trigeminal neuropathic pain.

Epidural morphine and buprenorphine for postoperative pain relief after hepatectomy

Postoperative pain relief with epidural morphine and buprenorphine was studied in 33 patients following hepatectomy. Morphine 2mg or buprenorphine 0.06mg in 10ml of normal saline was administered through an epidural catheter inserted at the Th10-11 or L3-4 interspace. Morphine injected at the lumbar level, as well as that injected at the thoracic level produced excellent and long-lasting (20.8 +/- 8.6 hours) pain relief. Respiratory rate decreased significantly following epidural morphine at the L3-4, but PaCO2 did not change. Buprenorphine injected at the thoracic level produced good and long-lasting (22.6 +/- 9.9 hours) pain relief, although buprenorphine injected at the lumbar level produced incomplete analgesia. The epidural administration of morphine 2mg at L3-4 or buprenorphine 0.06mg at Th10-11 may be recommended for postoperative analgesia following hepatectomy.

Treatment of pancreatic pain with interpleural bupivacaine: an open trial.

This study comprised 12 patients admitted for interpleural catheter treatment of chronic pancreatic pain. After the insertion of a left-sided interpleural catheter, 20 ml of bupivacaine 0.5% plain was given, followed by top-ups of 10-20 ml bupivacaine 0.5% as needed. Catheters were left in situ for 12-30 h. Immediate pain relief was achieved in all patients. Five patients had only a single blockade offering pain relief for a median of 33 days. One patient suffering from pancreatic carcinoma remained pain-free until death 45 days later. Seven patients returned for a second blockade after a median of 10 days. After this second blockade long-lasting pain relief was achieved in three patients for 70, 105 and 145 days. Two patients experienced pain relief lasting 11-14 days, while in two patients only a short-lived effect was observed, 3-8 days. Unimportant pneumothorax occurred in one patient. No cardiovascular or respiratory side-effects were recorded. We consider interpleural blockade an alternative worth further investigations in the future in the treatment of patients suffering from chronic pancreatic pain.

Gamma knife surgery with a dose of 75 to 76.8 Gray for trigeminal neuralgia.

OBJECT: The author presents a large series of patients with idiopathic trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS), at a maximum dose of 75 to 76.8 Gy, and followed up in a nearly uniform manner for up to 4.6 years. METHODS: Two hundred ninety-three patients were treated and followed up for at least 6 months (range 0.4-4.6 years, median 1.9 years). At the final follow-up review, there was complete (100%) pain relief without medicines in 64 patients (21.8%), 90% or greater relief with or without small doses of medicines in 86 (29.4%), between 75 and 89% relief in 31 (10.6%), between 50 and 74% relief in 19 (6.5%), and less than 50% relief in 23 patients (7.8%). Recurrent pain requiring a second procedure occurred in 70 patients (23.9%). Kaplan-Meier analysis showed that 100%, 90% or greater, and 50% or greater pain relief was obtained and maintained for 3.5 to 4.1 years in 5.6, 23.7, and 50.4% patients, respectively. Of 31 patients who described pain relief ranging from 75 to 89%, 80% of patients described it as good and 10% as excellent; of 17 patients who reported between 50 and 74% pain relief, 53% described it as good and none as excellent (p = 0.014). Dysesthesia scores greater than 5 (scale of 0-10, in which a score of 10 represents excruciating pain) occurred in four (3.2%) of 126 patients who had not undergone prior surgery; all these patients obtained either good or excellent relief from TN pain. There were 36 patients in whom the TN had atypical features; these patients were less likely to attain at least 50% or at least 90% pain relief compared with those without atypical TN features (p = 0.001). CONCLUSIONS: Gamma knife surgery is a safe and effective way to relieve TN. Patients who attain between 75 and 89% pain relief are much more likely to describe this outcome as good or excellent than those who attain between 50 and 74% pain relief.

Postoperative intramuscular dextromethorphan injection provides postoperative pain relief and decreases opioid requirement after hemorrhoidectomy.

BACKGROUND: Previous studies have shown that dextromethorphan (DM) produces an analgesic/antihyperalgesic effect. This study was designed to examine whether postoperative DM intramuscular (i.m.) injection could reduce post-hemorrhoidectomy pain. METHODS: At the end of the surgery, patients in the study group (n = 30) were given an intramuscular injection of 40 mg DM and 20 mg chlorpheniramine (CPM) while in the study group (n = 30), the patients were given intramuscular 20 mg CPM only. Pethidine (1 mg/kg, i.m.) was prescribed for postoperative pain relief if required. The time to first pethidine injection, total pethidine consumption, worst pain score, and pethidine-related side effects were recorded for 48 h postoperatively. RESULTS: The time from the end of operation to the first pethidine injection was 5.4 +/- 1.6 h and 17.8 +/- 3.7 h (P = 0.006) in the control group and the study group, respectively. Total pethidine consumption was 139.5 +/- 11.5 mg and 77.5 +/- 12.2 mg (P < 0.001) in the control group and the study group, respectively. The worst VAS score was 7.5 +/- 0.2 and 7.1 +/- 0.2 (P = 0.09) in the control and the study groups, respectively. The number of patients who required pethidine injection was 29 and 21 (P < 0.005) in the control and the study groups, respectively. The number of patients who suffered pethidine-related side effects was 7 and 1 (P < 0.025) in the control and the study groups, respectively. CONCLUSIONS: We found that intramuscular DM given at the end of operation could provide good postoperative pain relief and decrease the pethidine requirement after hemorrhoidectomy.

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.

Outcome assessment following limited wrist fusion: objective wrist scoring versus patient satisfaction.

Eighteen nonrheumatoid patients were reviewed an average of 4.4 years following limited wrist fusion to evaluate whether patient satisfaction or objective wrist scoring more closely correlated with functional outcome. Range of motion, grip strength, pain relief, radiographs, and patient satisfaction were assessed by examination and interview, and each wrist was scored based on a clinical scoring system described by Cooney. Twelve patients (67%) were very satisfied with their results, and six (33%) were dissatisfied. Thirteen (72%) experienced good pain relief, 12 of whom denied functional restrictions. Six patients (33%) reported suboptimal wrist function, and four indicated they had inadequate pain relief. Despite high levels of satisfaction in 12 patients, the objective wrist scores were only fair and poor. These low wrist scores unreliably reflected functional outcome. Patient self-assessment of wrist performance, however, was uniformly predictive. pain relief was more critical to patient satisfaction than residual range of motion. Therefore, compared to objective wrist scoring, consideration of patient satisfaction may allow more accurate prediction and assessment of functional outcome following limited wrist fusion. Satisfactory postoperative function appears to be more dependent on pain relief than residual motion.

Lumbar epidural blockade for management of pain in interstitial cystitis.

Thirteen patients with interstitial cystitis (IC), whose predominant symptom was pelvic or urethral pain, were treated with a series of lumbar epidural local anaesthetic blocks over an 18-month period. Response was evaluated by interview and with voiding diaries and visual analogue scales (VAS) for pain. Of the 55 injections given, immediate pain relief (lasting longer than 24 h) was obtained from 41 (75%). The duration of subsequent pain relief varied considerably, ranging from 2 to 75 days (mean 15.1). pain relief was accompanied by significant improvement in sleep habit and quality of life. A good correlation was noted between verbally expressed pain and the recorded VAS pain scores. Urinary frequency and average voided volumes were unaffected by treatment. Two patients failed to obtain any relief. Apart from minor transient backache at the injection site, there were no complications from the procedure. Lumbar sympathetic epidural blockade is an excellent means of providing pain relief in interstitial cystitis.

Postoperative pain relief by preanesthetic administration of buprenorphine suppository in elective mastectomy

Seventy female patients scheduled for elective mastectomy were divided into three groups: Buprenorphine suppository (BPS) 0.4 mg group (n = 29); BPS 0.2 mg (n = 23) group; and control (scopolia extract and tannic acid suppository) group (n = 18). Suppositories were administered rectally to patients of each group one hour before induction of anesthesia. Plasma buprenorphine concentrations, sedation scores at entering the operating room, postoperative pain scores and side effects were evaluated. There were no significant differences in sedation effects of suppository among the three groups. Although there were significant differences in pain scores except at the time when patients left the operating room between BPS 0.2 mg group and the control group, postoperative pain relief in BPS 0.2 mg group was judged not enough. However, postoperative pain relief was more satisfactory in the BPS 0.4 mg group. Plasma concentrations of the BPS 0.4 mg group were higher than those of the BPS 0.2 mg group. Although nausea and vomiting were observed in 5 patients (17.2%) of the BPS 0.4 mg group and 4 patients (17.4%) of the BPS 0.2 mg group, respiratory depression and changes in blood pressure and heart rate were not observed in all groups. In conclusion, preanesthetic administration of the BPS 0.4 mg seemed to be useful for postoperative pain relief after elective mastectomy.