Does the Sciatic Nerve Approach Influence Thigh Tourniquet Tolerance During Below-Knee Surgery?

Abstract

In this prospective, randomized, blinded study we assessed thigh tourniquet tolerance when a Labat's or a posterior popliteal approach of the sciatic nerve was used for below-knee surgery. One-hundred-twenty patients were divided into two groups of 60. A posterior popliteal (Group 1) or a Labat's (Group 2) sciatic nerve block was performed with 25 mL 1% mepivacaine + epinephrine 1:200,000. In both groups, a femoral nerve block was achieved. Patient comfort during block performance, sensory block, success rate, and thigh tourniquet tolerance were recorded. Performance of the block was significantly more comfortable in Group 1 than in Group 2 (P < 0.01). Completeness of the block at t(30 min.) and success rate were comparable in both groups. Thigh tourniquet pain increased with time in both groups. No statistically significant difference was observed between groups. We conclude that despite a complete sensory blockade of the posterior femoral cutaneous nerve in 91% of the patients, Labat's approach of the sciatic nerve provides no better thigh tourniquet tolerance than the popliteal approach. The popliteal approach is as efficient but more comfortable for the patient and is the preferred technique for below-knee surgery.

Ultrasound-Guided Anterior Approach to Sciatic Nerve Block: A Comparison with the Posterior Approach

“…This result corresponds to clinical data showing that tourniquet pain is not affected by the presence of a posterior femoral cutaneous nerve block. 17 There are some limitations to this study. First, investigators who collected data were not blinded to group assignment since most of the measurements had to be taken during and immediately after sciatic nerve block.…”

Does Dexamethasone Improve the Quality of Intravenous Regional Anesthesia and Analgesia? A Randomized, Controlled Clinical Study

“…The incidence and intensity of tourniquet pain and associated hypertension have also been shown to be correlated with tourniquet time (16). In a recent prospective study (17), it is reported that Ͻ15% of patients at 30 min but more than 50% of patients at 70 min complained of tourniquet pain. In our study, the relatively short operative times and small values of intraoperative VAS and VPS make it difficult to draw conclusions about the possible effects of dexamethasone on tourniquet pain.…”

Lower extremity regional anesthesia: essentials of our current understanding

“…While one trial reported a higher success rate with the transgluteal approach (95% vs 45%; p<0.01),179 the other found no difference between the two groups (94%–98%) 180. Two RCTs (combined n=100) have compared the transgluteal and lateral popliteal approaches: both studies found a longer onset for sensory and motor block with the latter 161 181.…”