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Abstract
Please confirm that an ethics committee approval has been applied for or granted: Not relevant
Background and Aims A pericapsular nerve group (PENG) block can be used to reduce pain after hip surgery as part of a multimodal postoperative pain management. This approach targets the sensory branches of the anterior portion of the hip capsule originating from the lumbar plexus (L2-L4). More research is needed to fully understand the characteristics of this block. Since this approach is a field block, its efficacy is volume-dependent. In this study, we compared the spread of different volumes of dye using a PENG block approach in two body donors.
Methods Two male unembalmed human bodies were obtained from the human body donation program of the university (with written informed consent). The four hip regions were injected respectively with 5 ml, 10 ml, 15 ml or 20 ml of a custom-made mixture (10% latex, 1.5% methylene blue 10 mg/ml and 88.5% water) by an experienced anaesthesiologist under ultrasound guidance. The spread of the injectates was measured and compared using dissection of the hip regions.
Results Injections with 5 and 10 ml of dye did not result in staining of the targeted nerves. With 15 and 20 ml of dye, we observed a posterocranial spread without staining the targeted femoral, obturator or accessory obturator nerves. The dye was located on top of the ilium.
Conclusions To our knowledge, this is the first time a spread over the ilium has been described. This atypical posterocranial spread might explain clinical failure of PENG blocks in some patients, suggesting a steep learning curve to apply this relatively new block effectively.
Anterior view of right side of specimen 823. Legend: a = Tensor fasciae latae muscle, b = Femoral nerves, c = Ilium
Anterior view of right side of specimen 823 with indicated femoral nerves (purple). Legend: a = Tensor fasciae latae muscle, b = Femoral nerves, c = Ilium