COMPARATIVE STUDY BETWEEN ULTRASOUND AND NERVE STIMULATOR GUIDED SCIATIC NERVE BLOCK THROUGH THE ANTERIOR APPROACH.

INTRODUCTION: The aim of the current study was to compare block of the sciatic nerve through the anterior approach by two methods, namely, the nerve-stimulator guided and ultrasound-guided, with or without nerve stimulation, with regard to the ease of performance, reliability and safety of this approach. PATIENTS AND METHODS: 36 adult patients were randomly allocated equally into one of 2 main groups: "Nerve Stimulator-Guided Group (NSG)" where the nerve was located by nerve stimulator only and "Ultrasound guided group (USG)" where the sciatic nerves were blocked by a stimulated needle under guidance of the ultrasound. Assessment of performing each technique, sensory and motor blockades, occurrence of acute systemic toxicity and haematoma formation were compared. RESULTS: Only one-third of the sciatic nerves could be visualized by US. This did not affect the block execution time but caused less number of needle passes in a statistically significant value. Sensory and motor block showed significant differences between the 2 groups. Criteria of acute systemic toxicity and occurrence of hematoma were not reported in both groups. CONCLUSION: Results of the current study showed that the addition of ultrasound to nerve stimulator in the anterior approach to the sciatic nerve block added only little to the ease of performance, reliability and safety. This was because only one-third of the nerves could be seen. More practice, better machines and new blocking techniques may be needed to overcome the problem of anisotropy of the nerve.

Comparative study between ultrasound determination and clinical assessment of the lumbar interspinous level for spinal anesthesia.

BACKGROUND: The aim of the current study is to compare the accuracy of the ultrasound (US) versus clinical assessment for determination of the spinal level, using X-ray as the Gold Standard for control. METHODS: 200 patients were randomized into two equal groups. Patients in the Clinical Group were examined by landmarks to assess the Assumed Clinical Tuffier's Line, and then by fluoroscopy to determine the True Clinical Tuffier's Line. Patients in the Ultrasound Group were examined by the ultrasound to determine the Ultrasound Tuffier's Line. The results of both groups were compared in relation to the plain X-ray, done for each patient, which determined the Radiological Tuffier's Line. RESULTS: In the Clinical Group, the True Clinical Tuffier's line met the Assumed Tuffier's line in only 12% of the patients. In the remaining patients, wrong leveling ranged from one space above in 80% to 2 spaces above in 7% and in 1% of patients the line was at L2. In the Ultrasound Group, wrong leveling occurred in 22% of patients. The Ultrasound misidentification was less than one level in 17% and one level in 5% of patients. Ultrasound examination had a true limitation of 2% of patients. CONCLUSION: Ultrasound examination of the spine is recommended in patients planned for spinal anesthesia, as it is superior to clinical assessment in identification of the interspinous levels. This will decrease the hazard of spinal cord trauma.

Continuous sciatic nerve block: compartive study between the parasacral, lateral, and anterior approaches for lower limb surgery.

OBJECTIVE: The aim of the present study was to evaluate the ease and reliability of the anterior and lateral approaches to sciatic nerve block compared to the posterior parasacral approach, and their suitability for the specific factors in the patients, positions, and surgeries. Also, the insertion and usefulness of the continuous catheter technique was evaluated. METHODS: The study was carried out on 120 patients, ASA I, II and III, of both genders, age range between 20 and 70 years, scheduled for orthopedic, general and vascular lower limb surgery. Patients were enrolled in a prospective, randomized, double blind study. Patients were divided into three equal groups, 40 patients each. All the patients received femoral nerve block in addition to sciatic nerve block either parasacral (Posterior group), lateral (Lateral group) or anterior approach (Anterior group). This was followed by continuous femoral and sciatic nerve blocks in the postoperative period. Patients were assessed as regards the time, duration and intensity of the sensory and motor blocks and also the postoperative analgesia offered by the continuous block. They were also assessed for the hemodynamic changes accompanied these blocks. Radiological study was made to demonestrate the spread of different volumes of the drugs alongside the course of the sciatic nerve. RESULTS: The posterior parasacral approach is the easiest technique to perform and used successfully even in obese patients, but difficult to be done, if at all, in patients with limited movement such as multi-pelvic fractures. The anterior approach was found to be the best for the patients in the supine position, with best results as regards patients' satisfaction and sensory and motor blocks. Only, it is a technique that needs high experience especially in obese patients. The lateral approach was the least performed technique especially its high approach. However, it is useful in patients in supine position, and gives the best results in thin patients. The technique showed to be extremely difficult in obese patients. CONCLUSION: The insertion of a catheter for continuous nerve block was easy. These blocks provided good or excellent postoperative analgesia for all patients in the different groups and facilitated early mobilization which helped in preventing the lower limb srugery - related morbidity and mortality.