Knowledge of the innervation of the outer ear is crucial for surgery in this region. The aim of this study was to describe the system of the auricular nerve supply. On 14 ears of seven cadavers the complete course of the nerve supply was exposed and categorized. A heterogeneous distribution of two cranial branchial nerves and two somatic cervical nerves was found. At the lateral as well as the medial surface the great auricular nerve prevails. No region with triple innervation was found.

Femoral component malalignment is one of the main causes of persisting anterior knee pain after knee replacement. This study examined interindividual reproducibility in perioperative definition of the transepicondylar axis (TEA) as a reference for measuring the rotational alignment of the femoral component. Eight surgeons experienced in knee prosthetic surgery marked on Thiel-embalmed cadaver specimens the reference points that they would normally use to define the TEA during knee replacement. These were digitized by a video system, and all the spots defined by the surgeon were translated into a reference picture, allowing a digital analysis of the distances between all the spots marked. The maximal distance between the spots that the participants had marked as relevant for the TEA was 13.8 mm at the lateral and 22.3 mm at the medial epicondyle. Projecting all spots marked into one picture resulted in an area of 116 mm2 on the lateral and 102 mm2 on the medial epicondyle. The median range of the fault between two different participants was 6.4 mm on the lateral side (range 13.2 mm) and 9.7 mm on the medial (range 21.6 mm). Because the rotational alignment of the femoral component is extremely relevant for successful implantation of total knee prosthesis, the interindividual discrepancy in defining the TEA as reference is rather high. As this reference line is commonly used, the perioperative variance and the resulting rotational discrepancy of the femoral component must be considered.

While the frequency of adverse effects of acupuncture is unknown and they may be rare, knowledge of normal anatomy and anatomical variations is essential for safe practice and should be reviewed by regulatory bodies and those responsible for training courses.

Undercutting decompression is a common surgical procedure for the therapy of lumbar spinal canal stenosis. Segmental instability, due to segmental degeneration or iatrogenic decompression is a typical problem that is clinically addressed by fusion, or more recently by semirigid stabilization devices. The objective of this experimental biomechanical study was to investigate the influence of spinal decompression alone, as well as in conjunction with two semi-rigid stabilizing implants (Wallis, DynesysÒ) on the range of motion (ROM) of lumbar spine segments. A total of 21 fresh-frozen human lumbar spine motion segments were obtained. Range of motion and neutral zone (NZ) were measured in flexion-extension (FE), lateral bending (LAT) and axial rotation (ROT) for each motion segment under four conditions: (1) with all stabilizing structures intact (PHY), (2) after bilateral undercutting decompression (UDC), (3) after additional implantation of Wallis (UDC-W) and (4) after removal of Wallis and subsequent implantation of DynesysÒ (UDC-D). Measurements were performed using a sensor-guided industrial robot in a pure-moment-loading mode. Range of motion was defined as the angle covered between loadings of -5 and +5 Nm during the last of three applied motion cycles. Untreated physiologic segments showed the following mean ROM: FE 6.6°, LAT 7.4°, ROT 3.9°. After decompression, a significant increase of ROM was observed: 26% FE, 6% LAT, 12% ROT. After additional implantation of a semirigid device, a decrease in ROM compared to the situation after decompression alone was observed with a reduction of 66 and 75% in FE, 6 and 70% in LAT, and 5 and 22% in ROT being observed for the Wallis and DynesysÒ, respectively. When the flexion and extension contribution to ROM was separated, the Wallis implant restricted extension by 69% and flexion by 62%, the DynesysÒ by 73 and 75%, respectively. Compared to the intact status, instrumentation following decompression led to a ROM reduction of 58 and 68% in FE, 1 and 68% in LAT, -6 and 13% in ROT, 61 and 65% in extension and 54 and 70% in flexion for Wallis and DynesysÒ. The effect of the implants on NZ corresponded to that on ROM. In conclusion, implantation of the Wallis and DynesysÒ devices following decompression leads to a restriction of ROM in all motion planes investigated. Flexion-extension is most affected by both implants. The DynesysÒ implant leads to an additional strong restriction in lateral bending. Rotation is only mildly affected by both implants. Wallis and DynesysÒ restrict not only isolated extension, but also flexion. These biomechanical results support the hypothesis that postoperatively, the semirigid implants provide a primary stabilizing function directly. Whether they can improve the clinical outcome must still be verified in prospective clinical investigations.

In ten human cadaveric shoulder specimens four different parameters were documented prior to, and after, dissecting all passive stabilizers. These included the vertical, horizontal and mediolateral acromioclavicular distance, as well as the clavicular rotation. In addition, the same parameters were documented after acromioclavicular (AC) reconstruction using eight different techniques. The results showed a good reconstruction of the vertical ac‐distance. Most of the techniques, especially the coracoid‐sling procedure, led to a significant anterior displacement of the clavicle in relation to the scapula. To a lesser degree, most of the conventional procedures also resulted in a lateralization of the acromion and/or clavicular rotation. A bone anchor system for distal fixation in the base of the coracoid process and a medialized hole in the clavicle restored anatomy best. This new technique therefore is recommended for anatomical AC‐reconstruction.