Suprainguinal fascia iliaca block: does it block the obturator nerve?

Combined Pericapsular Nerve Group Block and Intrapelvic Lateral Femoral Cutaneous Nerve Block Is Associated With Decreased Opioid Consumption After Hip Arthroscopy: A Retrospective Cohort Study

Introduction

Ambulatory hip arthroscopies are associated with moderate-to-severe pain often requiring opioid analgesia. Novel motor-sparing blocks, the pericapsular nerve group (PENG) and lateral femoral cutaneous nerve (LFCN) block, have shown efficacy in hip surgery.

Purpose

We sought to investigate the analgesic benefits of these novel blocks in terms of opioid-sparing and discharge efficiency.

Methods

We conducted a retrospective cohort study with propensity score matching of 224 patients who underwent ambulatory elective unilateral hip arthroscopy. One group received a combined PENG and LFCN block (PENG/LFCN, n = 86), while a second group received only a PENG block (n = 26). A control group (n = 112) received no blocks. The primary outcome was postanesthesia care unit (PACU) mean opioid consumption. Secondary outcomes were maximum numeric rating scale (NRS) pain score, intravenous rescue analgesia, and PACU readiness-for-discharge times.

Results

The PENG/LFCN-block group required significantly less opioids than the control group in the PACU (25.98 ± 13.04 vs 14.58 ± 5.77, respectively) and were discharged earlier 2.72 ± 1.16 vs 4.42 ± 1.63 hours, respectively). The combined PENG/LFCN group also used less intravenous rescue opioids than the control group (0.47 ± 1.18 vs 1.44 ± 2.1 mg, respectively) and showed a significant difference in the highest NRS pain scores than the control group (6.01 ± 2.38 vs 6.77 ± 2.1 respectively). The PENG block alone group did not show a significant difference in opioid reduction (21.95 ± 15.83 vs 27.72 ± 15.01, respectively).

Conclusions

This retrospective study found that in patients who underwent ambulatory elective unilateral hip arthroscopy, a combined PENG and LFCN block was associated with expedited PACU discharge and a clinically significant reduction in postoperative opioid use. Further study is warranted.

A radiological cadaveric study of obturator nerve involvement and cranial injectate spread after different approaches to the fascia iliaca compartment block

Whether the fascia iliaca compartment block (FICB) involves the obturator nerve (ON) remains controversial. Involvement may require that the injectate spreads deep in the cranial direction, and might thus depend on the site of injection. Therefore, the effect of suprainguinal needle insertion with five centimeters of hydrodissection-mediated needle advancement (S-FICB-H) on ON involvement and cranial injectate spread was studied in this radiological cadaveric study. Results were compared with suprainguinal FICB without additional hydrodissection-mediated needle advancement (S-FICB), infrainguinal FICB (I-FICB), and femoral nerve block (FNB). Seventeen human cadavers were randomized to receive ultrasound-guided nerve block with a 40 mL solution of local anesthetic and contrast medium, on both sides. Injectate spread was objectified using computed tomography. The femoral and lateral femoral cutaneous nerves were consistently covered when S-FICB-H, S-FICB or FNB was applied, while the ON was involved in only one of the 34 nerve blocks. I-FICB failed to provide the same consistency of nerve involvement as S-FICB-H, S-FICB or FNB. Injectate reached most cranial in specimens treated with S-FICB-H. Our results demonstrate that even the technique with the most extensive cranial spread (S-FICB-H) does not lead to ON involvement and as such, the ON seems unrelated to FICB. Separate ON block should be considered when clinically indicated.