The local ethical board committee approved this study with an ethical approval report dated 18.03.2013 and numbered 2013/125. This study was conducted between 18.03.2013-24.06.2016 in the operating room of Republic of Turkey Health science Univercity Bagcilar Training and Research Hospital. This study has been prepared in accordance with the Principles of the Helsinki declaration. We obtained written informed consent from each patient. This study was computer-randomized in terms of anterior or posterior sciatic nerve block, single-blinded, and prospectively planned. At the beginning of the study, 80 patients were randomized and failed blocks were continued with general anesthesia. These patients were excluded from the study before registering in failed blocks and proceeding to the analysis stage. After the block was performed, the anesthesiologist who was following the patient underwent general anesthesia without knowing whether anterior or posterior sciatic nerve block was performed in failed blocks. A single-blinded anaesthesiologist performed all posterior or anterior sciatic nerve and femoral nerve blocks and left the operating room after the nerve block was completed and the patient was repositioned. Another anaesthesiologist followed the patient without knowing what approach had been previously used. Our study complies with consort rules. Consort checklist submitted as an attachment.
Inclusion criteria: Patients of both sexes who were aged between 18 and 65 years, had lateral and/or medial malleolus fractures and of the American Society of Anesthesiologists (ASA) class I-II.
Exclusion criteria: Patients with vascular disease, cardiac disease. Metabolic (Diabetes mellitus)-renal-hepatic disease. Neuropathic pain in lower extremity. Pregnancy. Hemodynamic instability. Drug use that is likely to cause metabolic acid-base imbalance. History for steroid use and allergy. Contraindications to regional anaesthesia. Alcohol drug addiction. Those who did not graduate from primary school were excluded from the study. Failed block, sciatic nerve was not visualized in patients, patients with delirium.
The variables of interest included patients’ age; gender; height; weight; operation time; tourniquet time; ASA classification; First fentanyl requirement time before operation and after blockade; First fentanyl requirement time after operation; mean fentanyl dose administered per patient before operation and after blockade; Mean fentanyl dose administered per patient after operation; motor and sensory block start and end times after sciatic and femoral block’s time to first diclofenac sodium administration; total dose of diclofenac sodium administered in 24 hours; visual analog scale (VAS) values; patient satisfaction; anaesthetic quality from the point of view of the anaesthesiologist; and surgical quality from the point of view of the surgeon.
Patient satisfaction: 0: failed, 1: weak, 2: moderate, 3: good, 4: excellent.11,12
Anaesthesia quality (anaesthesiologist) and surgical quality (surgeon): 1: Failed; general anaesthesia was required, 2: Moderate; complainant, complementary analgesic was needed, 3: Good; little complainant, no need for complementary analgesia, 4: Excellent; patients do not complain.11
The patients were informed about VAS one day before. The patients having no premedication. The patients were taken to the regional block room. Routine monitoring included; electrocardiogram, and noninvasive arterial blood pressure, and peripheral pulse oximeter monitoring. Sciatic nerve blocks using an anterior approach were performed using the Stimuplex® A needle (21G 0.80-150), which was positioned at 30° and isolated, in conjunction with a block nerve stimulator (Stimuplex HNS nerve stimulator; BRAUN, Germany) and ultrasound (Diagnostic ultrasound system, Model SDU 450 XL Class-1 type B; Shimadzu Corporation, Japan). A total of 40 mL of a local anesthetic solution, comprising 15 mL of 0.5% isobaric bupivacaine and 5 mL of 2% lidocaine and 20 mL isotonic sodium chloride, was prepared.
In both approaches, nerve stimulation was performed with a frequency of 2 Hz and with a 1-mA current, and the stimulus intensity was gradually reduced to 0.4 mA as long as a response was obtained.
Femoral nerve block: The nerve was visualized with concurrent USG, and the needle was oriented to the nerve. After the contraction of the vastus medialis, vastus intermedialis, and vastus lateralis muscles were visualized, a local anesthetic mixture of 20 mL was injected, and dissemination of the local anesthetic solution was imaged by USG (linear probe) (Figure 2).
Anterior sciatic nerve block: The sciatic nerve was imaged by USG (convex probe) along the needle route, and the needle was advanced to the nerve. When plantar flexion, dorsal flexion, and eversion of the foot were observed, 20 mL of local anesthetic mixture was administered and the local anesthetic spread was simultaneously imaged by USG (Figure 3).
Posterior sciatic nerve block: The USG probe was placed between the greater trochanter and the coccyx at the entry point of the needle, and the needle was advanced by imaging the nerve. When the plantar flexion, dorsal flexion, and eversion of the foot were observed, 20 mL of local anesthetic mixture was administered and the local anesthetic spread was simultaneously imaged by USG (Figure 4).
After the blocks were completed, the motor block was assessed by monitoring the movement of the ankle joint and knee and the sensory block was assessed using application of cold saline bag every minute; the block start times were recorded. When the patient was not receiving any cold stimulation on the sciatic and femoral stimulation areas, it was recorded as the start time of the full femoral-sciatic sensory block. Once the knee joint could not be moved, the time was recorded as the start time of the full femoral motor block. When the ankle joint was unable to move, it was recorded as the start time of the full sciatic motor block. After the block was fully achieved, a tourniquet was applied to the extremity to be operated and was inflated. Patients underwent surgery 30 min after the block was provided. One μg kg-1 fentanyl was injected intravenously in pain if the VAS value was 5 or more. Mean fentanyl dose administered per patient before operation and after blockade; Mean fentanyl dose administered per patient after operation; First fentanyl requirement time before operation and after blockade; First fentanyl requirement time after operation were recorded.
The time to first diclofenac sodium administration and the total dose of diclofenac sodium administered within 24 hours of the postoperative period were recorded. The first postoperative dose of diclofenac sodium was administered when a patient had VAS values of 5 or more.
All data were evaluated using SPSS 11.5 for Windows.
Calculation of sample size: Before initiating the study, the required number of participants was determined according to the results of a pilot study that included 10 patients in each group. In this earlier pilot study, the mean time of sciatic nerve sensory block onset ± standard deviation (SD) was 8.88 ± 4.87 min for Group A (anterior approach to sciatic nerve block + femoral nerve block) and 4.70 ± 2.05 min for Group P (posterior approach to sciatic nerve block + femoral nerve block). The sample size was calculated as 29 (n = 29) for Group A and 29 (n = 29) for Group P, with α = 5% and 90% power. Fifty-eight patients were enrolled in the present study.
The normality distribution of the data was assessed by the Shapiro-wilks test. Mean ± SD values for the parametric tests and medians (minimum–maximum) for the nonparametric tests were used. Categorical data were presented as %n. Independent samples t-test was used for binary comparison of group data, and the chi-square test was used for between-group comparisons of categorical data. P values <0.05 were considered statistically significant.