Estudo comparativo entre o bloqueio do nervo cutâneo femoral lateral associado ao bloqueio do grupo de nervos pericapsulares (PENG block) e o bloqueio da fáscia ilíaca supra inguinal, na analgesia pós-operatória das fraturas da extremidade proximal do fêmur: estudo prospectivo, controlado, aleatorizado e duplamente encoberto

Abstract

Background: Pain management is crucial for postoperative recovery after hip surgery. Patients who undergo peripheral nerve blocks consume fewer opioids than those who receive systemic analgesia. Although there are several options for regional anesthesia for this situation, there is no definitive technique of choice. Currently, ultrasound-guided suprainguinal fascia iliaca compartment block (SIFIB) and pericapsular nerve group block (PENG block) are prominent in the hip surgery field. However, the literature exhibits conflicting data on the comparative analgesia of these techniques. The SIFIB reaches the femoral, lateral femoral cutaneous, and less possibly the obturator nerves. On the other hand, the PENG blocks the articular branches of the femoral and accessory obturator nerves, without accessing fibers of the lateral femoral cutaneous nerve, which may create a bias in comparisons between these approaches. As PENG block only targets distal sensory branches, there is likely less quadriceps motor impairment than SIFIB, which justifies its use. This is the first study, to the best of our knowledge, that compares the association of lateral femoral cutaneous nerve (LFCNB) and PENG blocks to the SIFIB in postoperative pain management of hip fractures. Outcomes: The primary outcome was to evaluate whether the association between the LFCNB and the PENG block promotes postoperative’s hip fracture movement pain management equivalent to the SIFIB. For this, movement pain was measured at 6, 12, and 24 hours after the procedure. Secondary outcomes included measuring pain at rest, evaluating quadriceps motor function by dynamometry and strength index, comparing the total opioid dose in 24 hours and the incidence of its side effects. The timing of the first opioid request, as well as the incidence of block complications and postoperative delirium were also recorded. Methods: Sixty-six patients undergoing hip fracture surgeries, according to inclusion and exclusion criteria, were randomly allocated in two groups: control or experimental. In the control group, patients underwent SIFIB with 30 ml of 0.5% ropivacaine and LFCNB and PENG block with 20 ml and 10 ml of saline, respectively. In the experimental group, patients received LFCNB and PENG block with 20 ml + 10 ml of 0.5% ropivacaine, respectively, and 30 ml of saline in the SIFIB. Patients in both groups also received spinal anesthesia with 10 mg of isobaric bupivacaine. Results: The control and experimental groups presented similar median of score movement pain at 6, 12, and 24 hours postoperatively (Numerical Rating Scale -2 vs 2; 3.5 vs 3; 3.37 vs 2.81; p > 0.05). However, a difference was observed in the analysis of resting pain 12 hours after the procedure, with a lower median score for the experimental group (Numerical Rating Scale - 1 vs 0; p = 0.045). Regarding the evaluation of quadriceps strength and its index, there was less motor impairment in the experimental group, with significant differences at 6 hours (10 N vs 19 N; 0.4 vs 0.7; p < 0.001), 12 hours (13 N vs 22 N; 0.5 vs 0.81; p < 0.001), and 24 hours (18 N vs 23 N; 0.75 vs 0.86; p ≤ 0.05). The total dose of morphine administered in 24 hours and the time of the first opioid request postoperatively were equivalent between the groups. The incidences of block complications and opioid side effects were low in both groups and without differences. Conclusion: The association between LFCNB and PENG block provided postoperative pain management comparable to the SIFIB in hip fractures. However, the association between LFCNB and PENG block showed less motor impairment of the quadriceps when this outcome was quantified by dynamometry.