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Introduction Percutaneous radiofrequency facet denervation (PRFD) by thermocoagulation is a useful treatment for nonspecific thoracic pain syndrome. To guarantee that maximal thermal lesion is applied to the nerve, it is essential to have precise knowledge of the topography of the thoracic dorsal branches of the spinal nerves. This special anatomy was investigated, and the results were compared with the existing technique for PRFD, where the active needle tip is placed in the junction of the superior articular process and the transverse process. Methods Twenty thoracic spines of cadavers (10 females and 10 males) embalmed according to Thiel's method were bilaterally dissected. After careful removal of skin and subcutaneous fat tissue, the lateral and medial branches were traced centrally. In addition, the articular branch to the thoracic facet joint was traced peripherally. The distance of the medial branch to the inferior articular process at the level of the nerve passing the superior costotransverse ligament was measured. Results The dorsal branch bifurcates into lateral and medial branches medial to the superior costotransverse ligament. The medial branch runs laterally first to pass in between two parts of the intertransverse ligament running dorsally and to turn medially superficial to this ligament. The zygapophysial branch always originated from the medial branch passing the inferior articular process laterally by running caudally to turn medially and send branches to the capsule of the zygapophyseal joint. The distance of the medial branch lateral to the inferior articular process was constantly 3 mm. Conclusions The current technique of PRFD at the thoracic spine targets the medial branch distal to the separation of the articular branch, rendering the lesion ineffective at denervating the zygapophyseal joint. For selective thermocoagulation of the articular branches of the thoracic zygapophyseal joint, a new technique should be developed. We propose an anatomically informed needle position that can now be confirmed clinically. [ABSTRACT FROM AUTHOR]

Introduction The zygapophyseal joints represent one possible cause for back pain. Therefore, many interventions are targeting the denervation of the facet joints. The aim of this study is to describe the course of the medial branch of the dorsal branch of the spinal nerve and its articular branches to the zygapophyseal joints in the segments T10–T12. Methods The medial branches in the thoracic segments T10–T12 were dissected in 20 Thiel embalmed cadavers. An Eschenbach magnifying glass (4.0× magnification) was used during dissection preserving the articular branches. The topography and the branching pattern of the medial branches was observed. Results The course of the nerves in the segments T10–T12 differed from each other because of the different osseous anatomy of each segment. The medial branch at the segment T10 crossed the tip of the transverse process in 28 of the 40 hemivertebral specimens. In the remaining cases it passed superior to the transverse process. At T11 the medial branch ran constantly through an osteofibrous canal. At the segment T12 the medial branches showed a similar course to the medial branches in the lumbar region. In many cases two articular branches, which arose from the medial branch were identified. Conclusions The results of this study show a considerable anatomic variety at the segment T10. It also demonstrates that the transverse process is an important landmark to encounter the medial branch. Furthermore, the possibility of a double innervation of the facet joints should always be considered. [ABSTRACT FROM AUTHOR]