AN ANATOMICAL STUDY OF THE COURSE OF LUMBAR PLEXUS NERVES PASSING AT LEVEL OF THE QUADRATUS LUMBORUM BLOCK

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Background. The quadratus lumborum block (QLB) is an often-used regional anaesthetic block technique at level of L3 but it remains unclear which nerves of the lumbar plexus are reached. Aim. Therefore, the topography and course of nerves (subcostal nerve, SCN; iliohypogastric nerve, IHN; ilioinguinal nerve, IIN) passing ventral to the quadratus lumborum (QL) at level of L3 were investigated. Material and Methods. 60 cadavers (120 sides), embalmed with Thiel´s method, were investigated in supine position. The nerves ventral to the QL were identified and marked with head-coloured pins and dissected carefully to most distal point as possible to determine the nerve according to their innervation area. Results were documented and compared to the nerve courses described in literature. Results and Discussion. In total, 92 sides were assessable. In 51 cases, branches of the IHN accompanied the SCN as well as the IIN. The IIN and parts of the IHN crossed the QL-block level at L3. The topography of the SCN, IHN and IIN according to literature (entire IHN an IIN emerge together as a trunk), was found in 5 cases only. In 25 cases, the SCN, IHN and IIN crossed the QL separately, solely the IIN at level of L3. Conclusions. The IIN is the nerve, which will be reached at L3 level for the QLB. Only parts of the IHN will be reached, the SCN is much more cranial.