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Abstract
Please confirm that an ethics committee approval has been applied for or granted: Not relevant
Background and Aims A posterior pericapsular deep-gluteal block (PPD) is a regional approach aiming to anaesthetize the sensory fibres originating from the sacral plexus. Branches of the sciatic nerve, gluteal nerves and the nerve to the quadratus femoris muscle (NQF) provide sensory innervation of the posterior hip capsule and are therefore the main targets of a PPD. However, further experimental validation of a PPD is needed. In this study, we describe the spread of dye in the posterior hip region after PPD injection in a body donor, focusing on the NQF.
Methods Two male, unembalmed bodies were obtained from the human body donation program of the university and included in the study. Using ultrasound guidance, a PPD (Vermeylen et al.) was performed injecting 5 ml, 10 ml, 15 ml or 20 ml of dye using a custom-made mixture (10% latex, 1.5% methylene blue 10 mg/ml and 88.5% water) in the targeted area. Each of the four posterior hip regions were dissected and dimensions of the spread were obtained.
Results Despite consistent coverage of the posterior hip joint area, none of the hip regions showed staining of the NQF after PPD injection. Inconsistent injections, too low volumes of dye and post-mortem disruption of tissue integrity are possible explanations for the inadequate spread towards the target nerve.
Overview of experimental design
Posterior view of right side of specimen 823. Detailed view of the dye spread. Spread of dye inside the obturator internus muscle (A), partially affecting the anterior side of the sciatic nerve (B). The NQF is covered by the quadratus femoris muscle (C)
Conclusions In this study, we could not demonstrate an adequate spread to the NQF using a PPD injection of dye in the posterior hip region. We conclude that the effectiveness of the PPD block requires further anatomical and clinical validation.