New laparoscopic approach to the pudendal nerve for neuromodulation based on an anatomic study.

AIMS: The aim was to develop a new laparoscopic technique for placement of a pudendal lead. METHODS: Development of a direct, feasible and reliable minimal-invasive laparoscopic approach to the pudendal nerve (PN). Thirty-one embalmed human specimens were dissected for the relevant anatomic structures of the pelvis. Step-by-step documentation and analysis of the laparoscopic approach in order to locate the PN directly in its course around the medial part of the sacrospinous ligament and test this approach for feasibility. Landmarks for intraoperative navigation towards the PN as well as the possible position of an lead were selected and demonstrated. RESULTS: The visible medial umbilical fold, the intrapelvine part of the internal pudendal artery, the coccygeus muscle and the sacrospinous ligament are the main landmarks. The PN traverses the medial part of the sacrospinous ligament dorsally, medially to the internal pudendal artery. The medial part of the sacrospinous ligament has to be exposed in order to display the nerve. An lead can be placed ventrally on the nerve or around it, depending on the lead type or shape. CONCLUSIONS: A precise and reliable identification of the PN by means of laparoscopy is feasible with an easy four-step approach: (1) identification of the medial umbilical fold; (2) identification of the internal iliac artery; (3) identification of the internal pudendal artery and incision of the coccygeus muscle ('white line', arcuated line); and (4) exposition of the medial part of the sacrospinous ligament to display the PN.

The anterolateral ligament of the knee: A dissection study.

BACKGROUND: Recent studies have described the presence of the anterolateral ligament (ALL). However, there is still no consensus regarding the anatomy of this structure with the topic controversially discussed. The aim of this study was to provide an anatomical description of the ligamentous structures on the anterolateral side of the knee with special emphasis on the ALL. METHODS: Forty-four human cadaveric knees were dissected to reveal the ALL and other significant structures in the anterolateral compartment of the knee joint. The ALL was defined as a firm structure running in an oblique direction from the lateral femoral epicondyle to a bony insertion at the anterolateral tibia. RESULTS: The ALL was identified in 45.5% (n=20) of the dissected knee joints. The structure originates together with the fibular collateral ligament (45%) or just posterior and proximal to it (55%). The ligament has an extra-capsular, anteroinferior, oblique course to the anterolateral tibia with a bony insertion between Gerdy's tubercle and the fibular head. The ALL had its greatest extend at 60° of knee flexion and maximal internal rotation. CONCLUSION: The ALL is a firm ligamentous structure in the anterolateral part of the knee present in 45.5% of the cases. Given the course and characteristics of this structure, a function in providing rotational stability by preventing internal rotation of the knee is likely. CLINICAL RELEVANCE: The ALL might be an important stabilizer in the knee and may play a significant role in preventing excessive internal tibial rotation and subluxation of the knee joint.

Posterolateral corner of the knee: microsurgical analysis of anatomy and morphometry.

Reconstruction of the posterolateral corner (PLC) of the knee is essential to restore knee joint function. Controversy exists regarding a standardized nomenclature, the connective attachments and the relationships between them, and the frequency of occurrence among all structures of the PLC. Thirty human cadaveric knee specimens were investigated. The lateral collateral ligament, popliteus tendon, popliteofibular ligament, fabellofibular ligament, arcuate ligament, oblique popliteal ligament, posterior meniscofemoral ligament, and popliteal hiatus (including the popliteomeniscal ligaments) were studied. The length, diameter, variations, course, and morphology of these structures, as well as the position and dimension of the insertion, were measured and referenced the footprints to adjacent bony landmarks. Compared with existing studies, the lateral collateral ligament footprint was more proximal to the lateral femoral epicondyle (average, 3.61 ± 0.75 mm) and the popliteus tendon insertion was more distal and anterior to the lateral collateral ligament footprint (average, 5.69 ± 1.36 mm and 4.97 ± 1.73 mm, respectively). Only minor data have been published on the fabellofibular ligament (average length, 33.79 ± 4.98 mm; average diameter, 4.04 ± 1.22 mm), arcuate ligament (average length, 31.54 ± 2.82 mm; average diameter, 7.27 ± 1.56 mm), oblique popliteal ligament (average length, 45.56 ± 4.67 mm; average diameter, 14.90 ± 4.67 mm), posterior meniscofemoral ligament (average length, 23.75 ± 3.17 mm; average diameter, 3.62 ± 1.03 mm), and popliteomeniscal ligaments (average mediolateral popliteal hiatus diameter, 9.83 ± 2.16 mm; average superoinferior popliteal hiatus diameter, 8.23 ± 1.86 mm).

Anatomic characteristics and radiographic references of the anterolateral and posteromedial bundles of the posterior cruciate ligament.

BACKGROUND: Anatomic graft tunnel placement is reported to be essential in double-bundle posterior cruciate ligament (PCL) reconstruction. A measurement system that correlates anatomy and radiographs is lacking so far. PURPOSE: To define the femoral and tibial attachments of the anterolateral (AL) and posteromedial (PM) bundles and to correlate them with digital and radiographic images to establish a radiographic anatomy based on anatomic landmarks and evaluate whether radiographs can serve as an accurate method for intraoperative and postoperative assessments of tunnel placement. STUDY DESIGN: Descriptive laboratory study. METHODS: Fifteen human cadaveric knee specimens were used. After preparation, the insertion areas of the 2 fiber bundles were marked with colorants, and high-definition digital images were obtained. With radiopaque tubes placed in the center of each bundle's footprint, anteroposterior and lateral radiographs were created. A measurement grid system was superimposed to determine the position of the AL and PM bundles' femoral and tibial insertion areas on both digital images and radiographs. The measurement zones were numbered 1 to 16, starting in the anterosuperior corner and ending in the posteroinferior corner. RESULTS: On radiographs and digital images, the femoral centers of the AL and PM bundles were found in zones 2 and 7, respectively. The tibial centers of the AL and PM bundles were found at 47.88% and 50.93%, respectively, of the total mediolateral diameter, 83.09% and 92.29%, respectively, of the total anteroposterior diameter, and 3.53 mm and 8.57 mm, respectively, inferior from the tibial plateau on radiographs. CONCLUSION: This study provides a geometric characterization of the AL and PM bundles of the PCL and establishes a reliable and feasible correlation system between anatomy and radiography based on anatomic landmarks. CLINICAL RELEVANCE: Accurate definition of the insertion sites of the PCL is essential for anatomic double-bundle reconstruction. The results of our study may be used as a reference for intraoperative and postoperative assessments of correct femoral and tibial tunnel placements.

Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures.

AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures.