Experimental studies related to visceral pain have been concentrated on the gastrointestinal tract which is the structure involved in the largest number of clinical complaints. In recent years the fundamental knowledge of the visceral pain pathways has increased and in the nearest future the number and quality of experimental visceral pain studies are expected to increase. A number of direct and indirect procedures are available to investigate mechanisms of visceral pain in man. Various physiological reactions have also been used to assess the visceral pain pathways. The GI tract transducts multiple sensory modalities: mechano-, thermo- and chemosensitive stimuli. Thermal stimulation, together with mechanical and electrical stimuli, may provide the possibility to determine differentiated responses to the different stimulus modalities. As for cutaneous stimulation, this multi-modal approach can be used to assess patients with various disorders of the GI tract and the efficacy of pharmacological interventions. The spatial and temporal summations are also important mechanisms for visceral pain. In various visceral pain conditions the central nervous system may be hyperexcitable. Summation of nociceptive input from viscera is expected to play an important role in visceral pain conditions. The other aspect of visceral hyperexcitability and summation is related to the referred pain areas. Referred pain has been suggested as a manifestation of central hyperexcitability related to nociceptive visceral input. In experimental studies it is possible to investigate the effect of repeated nociceptive visceral stimuli. The major obstacles for human studies on pharmacological intervention of experimental visceral pain are; large inter- and intra-individual variability, and lack of experimental techniques to study differentiated responses.

In this study, postoperative pain treatment in 60 ASA I-II patients aged between 25-60 who underwent abdominal surgery was assessed regarding analgesic efficacy and side effects with PCA. The patients in this randomized double bilind study were divided into three groups and no premedication was given. Thiopental 5-6 mg/kg, fentanyl 1 µg/kg and vecuronium 0.1 mg/kg were administered for induction and anesthesia was maintained by the mixture of O2 % 50, N2O % 50, and isoflurane. The solutions given to the patients were:
Grup A: 100 ml isotonic NaCl solution with morphine hidrochloride 100 mg (1 mg/1ml)
Grup B: 100 ml isotonic NaCl solution with meperidine 1000 mg (10 mg/ml)
Grup C: 100 ml isotonic NaCl solution with metamizol 10.000 mg (100 mg/ml)
All patients received 0.05 ml/kg from the prepared solution when their pain score were 2 or greater in the recovery room. The PCA pump was programmed as a bolus dose of 1 ml and lockout time of 10 min. The patients were assessed every hour for the first four hours, then every 2 hours for the next 4-24 hours and every 4 hours for the 24-48 hours of the postoperative period. Blood pressure, heart rate, respiratory rate, side effects, sedation scores, the number of request, the amount of the delivered solution and verbal rating scale (VRS) score were recorded. The comparison of the data were statistically evaluated with Turkey-Kramer and Pearson Correlation Analise methods. Analgesia was significantly better in the morphine and meperidine groups (p<0.05). The consumption of the drug (p<0.05) and the number of request (p<0.05) were higher but the frequency of side effects was lower in the metamizol group. No correlation was found between the number of request and the consumption of the drug. In the morphine and meperidine groups, the side effects were clinically well tolerated and respiratory depression was not seen. In conclusion, we observed that the level of analgesia was better with the opioids and the incidence of side effects was low with the non-opioid. More investigations shoud be done in order to compare the effects of the opioids and non-opioids.

Epidural application of drugs is still the choice of treatment in selected patients. However, the fibrosis developing around the catheter is a frequent and disabling problem. Inspiring from the idea of neuroplasty against fibrous tissue formation in failed back surgery syndrome, we aimed to relieve injection related burning pain due to fibrosis, by administering hypertonic saline and steroids. Three cases; two cancer patients and one non-cancer patient had epidural port implantation for long-term drug delivery. However the patients had epidural fibrosis and injection related pain after a while. After hospitalisation, epidural neuroplasty with 5 ml of bupivacaine 0.5 %, 4 ml of hypertonic saline and 40 mg of methylprednisolone was applied to breakdown the scar tissue. In all cases injection related pain was treated. The procedure was repeated successfully in two cases due to the reoccurrence of pain during their follow up. We have concluded that either cancer or non-cancer pain, when fibrosis and injection related pain develops due to use of epidural route, epidural neuroplasty can be used safely and effectively.

The purpose of this study was to compare the efficacy of tramadol (T), which is a centrally effective analgesic, and bupivacaine (B), in a double-blind, randomized study of 57 female patients with a median age of 30.17 ± 7.21 after laparoscopic gynecologic surgery. Patients were allocated randomly to one of the five groups and recieved 10 ml of: I. saline (n=12), II. 100 mg tramadol (n=12), III. 100 mg tramadol in 0.5 % bupivacaine with epinephrine (1/200.000) (n=11), IV. 0.5 % bupivacaine with epinephrine (1/200.000) (n=11) injected into the mesosalpinx. In the fifth group (n=11) 100 mg tramadol was administered intravenously at the end of the operation. Each patient was asked to degree her pain via 100 mm Visuel Analogue Scale, 30 minutes, 3, 6, 24 hours after the end of the operation. The time and amount of analgesic drug, complications, the time needed to return to normal activities were noted. The best postoperative analgesia was observed in the third group.

The stellate ganglion is formed by the fusion of the inferior cervical and first thoracic paravertebral smpathetic ganglia. Blockade of stellate ganglion is used for the treatment of painful /nonpainful pathologies of face, shoulder and upper extremity. We have retrospectively evaluated the outcome efficacy and complications of SGB with radiofrequency thermocoagulation in patients who admitted to Algology Department between Jan. 1999 and Sep. 2000 suffering from upper extremity pain due to various reasons. RFTC of SG was performed to patients who responded positively to 2 of the 3 prognostic SGB with either the occurance of Horner Syndrome or heat increase in thermographic evaluation. The VAS values were evaluated before, 3 months and 6 months later. The opioid consumption of the patients were evaluatedat the end of the 6th month. The VAS values of the patients were found to be significantly lower at the end of the 6th month.To 23 patients who had no pain relief or short pain relief, the procedure was repeated. 11 were treated with different treatment options. We conclude that application of radiofrequency thermocoagulation to stellate ganglion is an effective and safe method of analgesia

The antinociceptive effects of intraperitoneal injection of central acting drugs on tail-flick response of the mice were determined. This study was performed after the approval of Adnan Menderes University Laboratory Animals Ethics Committee. Initially, weight of mice were measured and their tail flick responses were recorded. Twenty-four hours later, diazepam (5 and 50 mg/kg), midazolam (1 and 10 mg/kg), phenytoin (50 mg/kg), biperiden (30 mg/kg), nicotine (5 mg/kg) and atropine (30 mg/kg) were administrated intraperitoneally. The tail-flick latencies were reduced significantly in 5 mg/kg diazepam and 10 mg/kg midazolam injected groups. On the other hand, the tail-flick latencies were increased significantly in diazepam (50 mg/kg), phenytoin, biperiden, and nicotine injected groups. These results suggest that phenytoin, biperiden, and nicotine have antinociceptive and diazepam and midazolam have dose-dependent hyperalgesic effects. In conclusion, hyperalgesic and antinociceptive effects of central acting drugs should be considered when they are combined with analgesic drugs during acute or chronic pain treatment.

Preoperative use of nonsteroidal antiinflammatory drugs in the control of pain following oral surgical operations was evaluated in this clinical study. Four types of NSAID having different chemical structures (diflunisal, naproxen natrium, diclofenac kalium, etodolac) were used preoperatively. The drugs were given in single dose, double blindly and their effects on pain control were compared as well as the side effects. No statistically significant difference between the drugs were found in terms of control of postoperative pain