Arterial supply of the distal humerus.

PURPOSE: Distal humeral fractures are rare, but severe injuries, the treatment of which is often accompanied by serious complications and its outcome strongly depends on the quality of surgical therapy. Non-union is a common entity, compromising clinical results and requiring revision surgery. Osteonecrosis is an underestimated etiologic factor in the development of non-union. The present study aims to display the distribution patterns of the arterial vessels at the distal humerus, to correlate the displayed vessels with local nutrient foramina and to disclose an endangerment of these structures by common osteosynthetic implants. METHODS: Eight plastinated fresh frozen upper extremities were digitally analyzed regarding the vascular density of the cancellous bone, by calculating the ratio of area comprised by arterial vessels and the area comprised by cancellous bone on sagittal cuts of the distal humerus. Possible differences in the vascular density of the medial epicondylar region, the lateral epicondylar region and a watershed area between the epicondyles and distal to the supracondylar region were investigated. On the basis of 200 macerated humeri, the distribution pattern of cortical nutrient foramina and their anatomic relation to properly applied common distal humerus plates were documented. RESULTS: The data show a significantly higher density of vessels per cancellous bone in the epicondylar regions than in the watershed region (p < 0.000, median 0.148 vs. 0.103). The analysis of the nutrient foramina showed distinct distribution patterns with a single foramen over the medial epicondyle (55 specimens, 27.5 %) and an area of several foramina at the posterior part of the lateral epicondyle (200 of the specimens, 100 %). In almost every specimen, the application of the osteosynthetic implants led to an overlay over the investigated nutrient foramina. DISCUSSION: Osteonecrosis and non-union are severe complications in the surgical treatment of distal humeral fractures. The biology of the bone, especially the blood supply, has to be respected as much as possible during open procedures, to optimize bony healing. This has to be considered when performing periosteal stripping or applying osteosynthetic plates over the postero-lateral and medial epicondyle. The watershed area of the distal humerus has to be considered as being prone to minor arterial blood supply and thereby non-union is possible, if the arterial vessels coming from the epicondyles are destroyed.

Traumatology of the superior thyroid horns in suicidal hanging--an injury analysis.

It appears still questionable whether fractures to the superior thyroid horns can be used for forensic reconstruction purposes regarding the functional mechanism causing compression of the neck soft tissues. Localisations and types of such fractures were documented in 118 cases of superior thyroid horn fractures caused by suicidal hanging. The placement of the ligature was above the larynx in 109 cases and in the remaining nine cases across the thyroid cartilage. As a secondary parameter the degree of ossification of thyroid cartilages and superior horns was used. Bone densities of typical cases (equidensities) were measured radiologically. Additionally, dummy tests were performed focused on two extreme shapes of superior thyroid horns to assess stress peaks using resin dummies and polarised light. Such peaks were located in the lower thirds of the horns close to their bases. With the larynx still cartilaginous, the base appears a typical location for fractures caused by suicidal hanging. An ossification pattern defined as "type 1" showed broad and osseous superior thyroid horns. If ossification was homogenous, fractures were located at the sites of maximum mechanical stress. In case of inhomogenous ossification, being the more common mode, the horn bases were more resistant to pressure and bending so that no fractures occurred. They were instead located at the sites of the greatest differences in density and distributed in an apparent random pattern. Narrow and deep insertions of the superior thyroid horns at the back surface of the upper thirds of the thyroid cartilages (posterior aspects) were classified as "type 2" ossification. Upon flexion, the long horns came into contact with the upper edges of the dorsal aspect creating a torque. Further flexion from an increasing impact by the ligature extended the long lever arm causing the base of the upper thyroid horn being broadly torn out of the dorsal aspect. The results suggest that localisations of fractures to the superior thyroid horns in connection with ossification patterns may be helpful for the reconstruction in suicidal hanging regarding the mechanics of the ligature in relation to its position around the neck.

[Treatment of proximal humerus fractures: relative position of different locking plates to the axillary nerve]. / Versorgung von Humeruskopffrakturen: Lagebeziehung proximaler Verriegelungsplatten zum N. axillaris.

OBJECTIVES: Placement of a proximal humerus locking plate through a percutaneous transdeltoid approach bears the advantages of a minimally invasive approach but may compromise the anterior branches of the axillary nerve. This anatomic study aimed to develop a risk profile for 6 types of modern proximal humerus locking plates as to their interference with the axillary nerve. MATERIALS AND METHODS: In this study six different implants (Arthrex®, DePuy®, Königsee®, Smith & Nephew®, Stryker® and Synthes®) were placed on the intact proximal humerus of 33 embalmed cadaveric upper extremities and the relative positioning between the axillary nerve and the screw holes was determined. RESULTS: All locking plates displayed an area of risk which concerned 3 out of 7 (Arthrex®), 4 out of 10 (DePuy®), 2 out of 9 (Königsee®), 3 out of 11 (Smith & Nephew®), 3 out of 11 (Stryker®) and 6 out of 12 (Synthes®) screw holes of the plate. CONCLUSIONS: Using the anterolateral percutaneous deltoid splitting approach the relative position of the axillary nerve to the holes of a specific implant is of relevance for avoidance of iatrogenic lesions to the nerve.

The role of the inter-/supraspinous ligament complex in stand-alone interspinous process devices: a biomechanical and anatomic study.

BACKGROUND: Lumbar spinal stenosis (LSS) with neurogenic intermittent claudication is one of the most common degenerative spinal diseases in the elderly. For patients over 65 years with LSS, open decompression is the most frequent spinal surgery. One problem associated with decompression surgery is the emergence of instability, which is found in varying grades of severity. For some patients with LSS, interspinous process devices (IPD) may be a viable alternative to open decompression. The purpose of this study is to examine the destruction and changes to the interspinous and supraspinous ligament complex after percutanous IPD implantation. METHODS: Biomechanical and anatomic assessments were performed on the lumbar spine (L1-L4) of 11 fresh human cadavers. The biomechanical examination assayed the force necessary to disrupt the interspinous-supraspinous ligament complex without and after implantation of an IPD. For the anatomic examination, one lumbar spine was plastinated. Serial 4-mm thick sections were cut in sagittal and horizontal planes. The macroanatomic positioning of the implants was then analysed. RESULTS: Biomechanics: The average age of the cadavers was 80.6±10.2 years. The minimum average disrupting forces measured 313.74±113.44 N without and 239.47±63.64 N after IPD implantation, a significant (p<0.018) decrease of an average 23.7%. Anatomy: After posterolateral percutaneous IPD implantation, the posterior third of the interspinous ligament, the supraspinous ligament, the thoracolumbar fascia and paraspinous muscles bordering the inter-/supraspinous ligament complex remained undamaged. CONCLUSION: The implantation of an interspinous "stand-alone" spacer significantly minimises the force necessary to disrupt the ISL/SSL complex. After posterolateral percutaneous IPD implantation, the thoracolumbar fascia and associated musculature, which act in synergy with the ISL/SSL complex to stabilise the vertebral column, remain intact.

Tibiofibular screw fixation for syndesmotic ruptures: a biomechanical analysis.

The mechanisms of injuries to the tibiofibular syndesmosis include isolated rupture and rupture in combination with ankle fractures. Current concepts of surgical treatment are fixation using bioabsorbable screws, syndesmotic stapling, syndesmotic hooks, and the widely used screw fixation. Postoperative care utilises passive motion of the ankle joint either with or without axial weight-bearing. The aim of our investigation was to quantify the motion of the mortise during axial load. Therefore, photoelastic tests, on the one hand, and biomechanical tests of cadaveric specimens, on the other, using axial loads of up to 2,000 N were used. Our photoelastic investigations showed force distribution through the screw into the cranial and caudal parts of the distal fibula. Biomechanical testing showed a progressive dehiscence in both ruptured and fixated specimens up to 2.89 (ruptured) and 2.42 mm (despite screw). Our findings strongly suggest a concept of partial weight-bearing at most to support regeneration of scar tissue and to prevent the appearance of instability in the ankle joint.

Topographical anatomy of central venous system in extremely low-birth weight neonates less than 1000 grams and the effect of central venous catheter placement.

Central venous catheterization is widely used in neonatology. Although ultrasonic guidance for central venous catheter placement is available, complications occur significantly more frequently in infants, especially neonates, than in adults. This study seeks to determine the characteristics, topographical conditions, regional relationships, and diameters of the venous structures of the upper extremity and the thoracic central venous system in extremely small preterm neonates (mean: 900 g). Nine formaldehyde-fixed preterm stillborns were prepared (mean 27 2/7 weeks' gestational age). The anatomical preparation involved the complete thoracic wall, neck and shoulder region, and preparation of the upper extremities. It was shown that the course of the internal jugular vein can be influenced by rotation of the head. Maximum head rotation (80°) to the contralateral side leads the internal jugular vein to overlap the common carotid artery and sharpens the confluence angle of the internal jugular into the brachiocephalic vein. We propose that this has the potential to result in dislocation of the catheter. Less rotation of the head (<30°) is favorable as the internal jugular vein and common carotid artery run in parallel. Commonly used central venous catheters (2F-4F) may not occlude the vascular lumen completely. Small central venous cannulation using a single-orifice catheter through arm veins (1F) may also not occlude peripheral vessels of the upper extremity (cephalic and basilic veins). The right internal jugular vein has a straight course, appears suitable for central venous access and less hazardous, especially when using stiff catheters. The use of small straight wire guides is recommended.

Presentation of the microscopic vascular architecture of the radial head using a sequential plastination technique.

The purpose of this study was to demonstrate the peri- and intraosseous vascular architecture of the radial head and vascular interaction with surgical implants. Seventeen fresh human cadaveric elbows were sequentially plastinated beginning with arterial injection, followed by block and slice plastination of the whole elbow. With this technique, we obtained completely transparent cadaveric slices in which the peri- and intraosseous vascular architecture could be studied in its neutral position. In six of these elbows, radial head osteosynthesis was imitated with miniplates or fine threaded K-wires. Vascularization of the radial head occurred via branches of the radial recurrent artery on the ventral, lateral, and dorsal sides of the radial head and a branch of the ulnar artery--ramus periostalis ulnaris--medially and dorsomedially. Both arteries create a pericervical arterial ring around the radial neck. A branch of the interosseous artery--R. interosseous recurrence--supports the ventral and dorsal sides of the radial neck and the final branches of the nutrient artery support intraosseous vascularization. Vascular structures were damaged more severely by plates than by screws. The peri- and intraosseous vascularization of the radial head and the interaction between vascularization and the implants was shown. Plate fixation of radial head fractures leads to a higher level of implant-related destruction of the periosseous vascularization than screw fixation. Besides devascularization of the radial head due to the injury leading to a certain risk of fracture nonunion, additional implant-related injuries to the blood supply might increase the chance of radial head fracture non-union.

An anatomical study of the proximal hamstring muscle complex to elucidate muscle strains in this region.

Muscle strain injuries are common in sports, and a high incidence is reported for the hamstring muscles, especially in the proximal region, where the long head of the biceps femoris muscle is most frequently affected. To look for some architectural peculiarities, which would make this muscle vulnerable, 101 legs of embalmed human cadavers were dissected and descriptively examined, morphometric data were obtained in the proximal region, and slices of plastinated specimens were microscopically examined. The 3 muscles composing the proximal hamstring complex are partly twisted around each other and possess common fibrous adhesions. Biceps femoris (BF) and semitendinosus (ST) muscles form a common head, to which the ST contributes the majority of fascicles extending 9 cm down from the ischiac tuberosity, thereby attaching to the common tendon at a remarkable pennation angle. The first BF fascicles origin from the common tendon only at 6 cm distance from the ischiac tuberosity. It is concluded that the high incidence of proximal BF strains may be a misinterpretation due to insufficient imaging and the complex architecture. It is suggested that the pennation angle at which the ST inserts to the common tendon makes this muscle especially vulnerable for strains during forced eccentric contractions.

Biomechanical comparison of tension band- and interfragmentary screw fixation with a new implant in transverse patella fractures.

AIM: The aim of the present study was to compare the primary fixation stability and initial fixation stiffness of two established fixation techniques, the tension band wiring technique and interfragmentary screw fixation, with a mini-screw fragment fixation system in a model of transverse patella fracture. It was hypothesised that the biomechanical loading performance of the fragment fixation system would not significantly differ from the loading characteristics of the two established methods currently investigated. MATERIALS AND METHODS: Ninety-six calf patellae were used in this biomechanical model. A standardized transverse patella fracture was induced and three different fixation methods, including the modified tension band wiring technique, interfragmentary screw fixation, and the mini-screw fragment fixation system, were used for fragment fixation. Specimens were mounted to a loading rig which was secured within a material testing machine. In each fixation group, eight specimens were loaded to failure at a simulated knee angle of either 0 degrees or 45 degrees . Another eight specimens were submitted to a polycyclic loading protocol consisting of 30 cycles between 20N and 300N at a simulated knee angle of 0 degrees or 45 degrees . The residual displacement between the first and the last cycle was recorded. Differences in the biomechanical performance between the three fixation groups were evaluated. RESULTS: No significant differences between the three fixation groups were observed in the parameters maximum load to failure and linear fixation stiffness with monocyclic loading. Specimens being loaded at 45 degrees showed significantly lower maximum failure loads and linear stiffness when compared with 0 degrees . During polycyclic loading, no significant differences in the residual displacement were observed between the groups at 0 degrees loading angle, while at 45 degrees , residual displacement was significantly higher with tension band fixation when compared with interfragmentary screw fixation or the fragment fixation system. CONCLUSION: The biomechanical performance of the fragment fixation system was comparable to interfragmentary screw fixation and superior to the tension band wiring technique. Given the advantages of a system which provides interfragmentary compression and which simplifies fracture fixation after open or closed reduction, we believe the fragment fixation system to be an adequate alternative in the osteosynthesis of transverse patella fractures.

Abnormal muscles that may affect axillary lymphadenectomy: surgical anatomy.

Purpose The present study aimed at summarizing and presenting the anomalous muscles that a surgeon might encounter during axillary lymphadenectomy (AL). Methods For this purpose, both the anatomical and surgical literature was reviewed and an anatomical study on 107 cadavers was carried out. Furthermore, based on the anatomical features of the anomalous muscles that came up during our study and taking into consideration the landmarks of the AL, we further analyzed the complications that may arise from each of these muscles, along with their preoperative and intraoperative recognition and management. Results The literature review revealed that there are three supernumerary muscles that may affect the AL, namely the Langer's axillary arch, the pectoralis quartus and the chondroepitrochlearis muscles, as well as the aplasia of the lower part of the pectoralis major muscle. Eight out of the 107 (7.48%) cadavers that we dissected had such an abnormal muscle in the axilla. Specifically, the axillary arch was found unilaterally in five cadavers (4.67%) and the pectoralis quartus muscle was present unilaterally in three cadavers (2.8%). One cadaver had both an axillary arch and a pectoralis quartus muscle in the right side. The abdominal and almost the whole sternocostal portion of the pectoralis major as well the pectoralis minor muscle were absent in one cadaver (0.93%). The chondroepitrochlearis muscle was not found in any of the cadavers that we dissected. Conclusions The present study offers the necessary preoperative knowledge for recognizing these muscles during AL, avoiding thus the complications that may arise from them.

How accurate is image-free computer navigation for hip resurfacing arthroplasty? An anatomical investigation.

BACKGROUND: The existing studies concerning image-free navigated implantation of hip resurfacing arthroplasty are based on analysis of the accuracy of conventional biplane radiography. Studies have shown that these measurements in biplane radiography are imprecise and that precision is improved by use of three-dimensional (3D) computer tomography (CT) scans. To date, the accuracy of image-free navigation devices for hip resurfacing has not been investigated using CT scans, and anteversion accuracy has not been assessed at all. Furthermore, no study has tested the reliability of the navigation software concerning the automatically calculated implant position. The purpose of our study was to analyze the accuracy of varus-valgus and anteversion using an image-free hip resurfacing navigation device. The reliability of the software-calculated implant position was also determined. METHODS: A total of 32 femoral hip resurfacing components were implanted on embalmed human femors using an image-free navigation device. In all, 16 prostheses were implanted with the proposed position generated by the navigation software; the 16 prostheses were inserted in an optimized valgus position. A 3D CT scan was undertaken before and after operation. RESULTS: The difference between the measured and planned varus-valgus angle averaged 1 degrees (mean +/- SD: group I, 1 degrees +/- 2 degrees ; group II, 1 degrees +/- 1 degrees ). The mean +/- SD difference between femoral neck anteversion and anteversion of the implant was 4 degrees (group I, 4 degrees +/- 4 degrees ; group II, 4 degrees +/- 3 degrees ). The software-calculated implant position differed 7 degrees +/- 8 degrees from the measured neck-shaft angle. These measured accuracies did not differ significantly between the two groups. CONCLUSIONS: Our study proved the high accuracy of the navigation device concerning the most important biomechanical factor: the varus-valgus angle. The software calculation of the proposed implant position has been shown to be inaccurate and needs improvement. Hence, manual adjustment of the implant position in the software-planning step is frequently required.

Is a valgus position of the femoral component in hip resurfacing protective against spontaneous fracture of the femoral neck?: a biomechanical study.

The aim of our study was to investigate whether placing of the femoral component of a hip resurfacing in valgus protected against spontaneous fracture of the femoral neck. We performed a hip resurfacing in 20 pairs of embalmed femora. The femoral component was implanted at the natural neck-shaft angle in the left femur and with a 10 degrees valgus angle on the right. The bone mineral density of each femur was measured and CT was performed. Each femur was evaluated in a materials testing machine using increasing cyclical loads. In specimens with good bone quality, the 10 degrees valgus placement of the femoral component had a protective effect against fractures of the femoral neck. An adverse effect was detected in osteoporotic specimens. When resurfacing the hip a valgus position of the femoral component should be achieved in order to prevent fracture of the femoral neck. Patient selection remains absolutely imperative. In borderline cases, measurement of bone mineral density may be indicated.

[Aspects of finger mobility]. / Aspekte der Fingerbeweglichkeit.

The movements of the finger, centrally induced and controlled via open or closed loops, need the simultaneous action of several muscles and muscle groups. In this way, rigid differentiation between antagonists and synergists is functionally abolished. Synchronous flexion and extension of a finger needs not only a palmar flexion and a dorsal extension motor system but also a third oblique running motor system. This is given by the interosseous-lumbricalis system. Opposition and repositioning of the thumb require muscle configuration other than that provided by the other fingers.

Biomechanical comparison of four different miniscrew types for skeletal anchorage in the mandibulo-maxillary area.

This study compared four miniscrew types for skeletal anchorage (Aarhus, FAMI, Dual Top and Spider) regarding their biomechanical properties contributing to primary stability. Insertion torque measurements and pull-out tests in axial (0 degrees ) as well as in the 20 degrees and 40 degrees direction were performed. Stiffness of the screw-bone construct was calculated from the load-displacement curve. Conic FAMI and Dual Top screws had higher insertion torques. Insertion torques were raised by drill-free insertion of FAMI and Dual Top screws. Statistically significant differences were found between the 4 screw types in pull-out tests. The highly significant differences between the four screws for peak load in the axial (0 degrees ) and 20 degrees direction were not apparent in 40 degrees angular loads. For the conical screws, peak load values increased in angular compared with axial load. The Dual Top screw achieved the highest values for peak load and stiffness. 12 Dual Top and 1 Spider screw heads fractured in the pull-out tests. A conical drill-free screw design achieves higher primary stability compared with cylindrical self-tapping screws. This effect was more obvious in insertion torque estimations rather than in pull-out tests. The Dual Top screws, although biomechanically superior to other screw types, were most prone to fractures.

The mobile Condylus tertius occipitalis and fractures of the hypochordal clasp.

The Condylus tertius is defined as a small bony hunch on the anterior surface of the clivus. Its presence means an enormous functional impairment of the upper head joint, looking at the 3-point-contact between the skull base and the upper cervical vertebrae. In 10 of the 2000 forensic examined bodies, analyses of neck vertebra + skull base revealed this feature. The origin of these findings is discussed, as stated in the literature of embryology, to be a suboccipital hypochordal plate. So in one of the cases the condylus was found at the hypochordal plate itself whereas the so-called socket was lying at the margin of the clivus. In three cases there was found a free body between the apex of the Dens and the Clivus forming a mobile Condylus tertius. In our opinion its position varies over the anterior arch of the atlas and the apex of the dens as a result of rotatory forces between the atlas and axis and physiological strain. Examples are given to elucidate this. There is a difference in the differentiation of the deposited material according to functional demand. A pressure bed (i.e. a Condylus tertius) is formed when a bony structure is deposited on the clivus. This functional prospect relativises the hypothesis of a purely constitutional genesis of the Condylus tertius. A fracture of the hypochordal clasp being joined with a bony connection to the anterior atlantic arch is described for the first time.

Subchondral bone density of the radial head measured with subtraction densitometry.

The purpose of this study was to develop a two-dimensional density distribution pattern of the subchondral cortical bone of the radial head using subtraction densitometry. The bone density of 32 normal specimens and five with macroscopic signs of osteoarthritis was measured before and after milling off the cortical bone surface. Electronic subtraction gave the density of the subchondral cortical bone. Twenty-one specimens had areas of high bone density in the ulnar-dorsal area, five specimens showed a ventral and ulnar density maximum and six had a density maximum in the center of the radial head joint surface. No density maximum was seen in the lateral part of the joint surface. The density maximum shifted towards the dorsal-ulnar part of the radial head with decreasing total subchondral bone density. Osteoarthritic radial heads had the same distribution as non-arthritic specimens. Eccentric subchondral bone density reflects eccentric radiohumeral force transmission. This could be a reason for development of radiohumeral arthritis or the failure of radial head prostheses. Bone density patterns correlate with the incidence of radial head fractures and fracture line may be positioned between areas of high and low densities.

Chondral thickness and radii of curvature of the femoral condyles and talar trochlea.

To localize optimal donor regions for osteochondral graft transplantation, the chondral thickness and the radii of curvature of femoral condyles and the talar trochlea were determined. Optosil impressions of the articular surfaces of ten formalin fixed distal femora and talar domes were prepared. Therefrom, 5-mm thick frontal sections were made in order to measure the radii of curvature. Femoral condyles and talar trochleas were sliced sagittally into 2-mm thick sections. Chondral thickness was measured on x-rays. Talar cartilage thickness measured 0.7 to 2.0 mm. Cartilage thickness of the femoral condyles was 0.7 mm to 3.1 mm. The smallest radial values of the talar surface were proximal and distal. Flattening of the medial and lateral talar margins and of the central articular surface was evident. For the femur, the curvature was greater in the edge areas than in the central region. For talar defects, the grafts should be taken from the condylar edges, where the chondral thickness is decreased.

Reconstruction of a Mason type-III fracture of the radial head using four different fixation techniques. An experimental study.

We have evaluated four different fixation techniques for the reconstruction of a standard Mason type-III fracture of the radial head in a sawbone model. The outcome measurements were the quality of the reduction, and stability. A total of 96 fractures was created. Six surgeons were involved in the study and each reconstructed 16 fractures with 1.6 mm fine-threaded wires (Fragment Fixation System (FFS)), T-miniplates, 2 mm miniscrews and 2 mm Kirschner (K-) wires; four fractures being allocated to each method using a standard reconstruction procedure. The quality of the reduction was measured after definitive fixation. Biomechanical testing was performed using a transverse plane shear load in two directions to the implants (parallel and perpendicular) with respect to ultimate failure load and displacement at 50 N. A significantly better quality of reduction was achieved using the FFS wires (Tukey's post hoc tests, p < 0.001) than with the other devices with a mean step in the articular surface and the radial neck of 1.04 mm (SD 0.96) for the FFS, 4.25 mm (SD 1.29) for the miniplates, 2.21 mm (SD 1.06) for the miniscrews and 2.54 mm (SD 0.98) for the K-wires. The quality of reduction was similar for K-wires and miniscrews, but poor for miniplates. The ultimate failure load was similar for the FFS wires (parallel, 196.8 N (SD 46.8), perpendicular, 212.5 N (SD 25.6)), miniscrews (parallel, 211.8 N (SD 47.9), perpendicular, 208.0 N (SD 65.9)) and K-wires (parallel, 200.4 N (SD 54.5), perpendicular, 165.2 N (SD 37.9)), but significantly worse (Tukey's post hoc tests, p < 0.001) for the miniplates (parallel, 101.6 N (SD 43.1), perpendicular, 122.7 N (SD 40.7)). There was a significant difference in the displacement at 50 N for the miniplate (parallel, 4.8 mm (SD 2.8), perpendicular, 4.8 mm (SD 1.7)) vs FFS (parallel, 2.1 mm (SD 0.8), perpendicular, 1.9 mm (SD 0.7)), miniscrews (parallel, 1.8 mm (SD 0.5), perpendicular, 2.3 mm (SD 0.8)) and K-wires (parallel, 2.2 mm (SD 1.8), perpendicular, 2.4 mm (SD 0.7; Tukey's post hoc tests, p < 0.001)). The fixation of a standard Mason type-III fracture in a sawbone model using the FFS system provides a better quality of reduction than that when using conventional techniques. There was a significantly better stability using FFS implants, miniscrews and K-wires than when using miniplates.

The relationship of the lingual nerve to the third molar region using radiographic imaging.

OBJECTIVE: Lingual nerve damage is a common complication during oral and maxillofacial surgery procedures to the third molar region. The anatomy of the lingual nerve is variable, therefore the precise knowledge of anatomy of this nerve is important for decreasing the damage risk. The purpose of this study was to determine the position and the shape of the lingual nerve in the third molar region using radiographic imaging. SETTING: The Anatomy Department of Cologne University in Germany. MATERIALS AND METHODS: Firstly, an anatomic dissection of the lingual nerve in the third molar region was done on 10 whole heads and one sagittal hemisection head specimen of adult cadavers. After marking the nerve, x-ray films were taken. Vertical and horizontal measurements were made from the radiographs with an electronic digital caliper. RESULTS: The mean vertical and horizontal distances of the nerve to the lingual crista and lingual plate of the mandible were found to be 9.5 +/- 5.2 mm and 4.1 +/- 1.9 mm respectively. Additionally, of the 21 lingual nerves examined, 17 (81%) were round and 4 (19%) were flat. CONCLUSIONS: The results reflect the relationship of the nerve to this area and may help the clinician to avoid the damage risk.

Morphometric parameters of the radial neck: an anatomical study.

INTRODUCTION: The purpose of this study was to describe the anatomy of the intramedullary canal of the radial neck for stem design of radial head prostheses. METHODS: Radial neck measurement was performed from the proximal edge of the radial tuberosity to the distal border of the articular surface on 40 macerated proximal radii using X-rays and Optosil imprints of the intramedullary canal. Radial neck to shaft angle was measured under image intensification. RESULTS: The neck length was 13.3 mm (range 8.0-20.0 mm) measured on X-rays and 13.5 mm (range 9.9-18.8 mm) on Optosil imprints. Concerning the neck's intramedullary canal we obtained a minimum diameter of 9.7 mm (range 6.3-16.4 mm) on X-ray. Corresponding Optosil imprints had a mean diameter of 11.6 mm (range 6.6-18.6 mm) at their proximal end, 10.5 mm (range 5.5-16.3 mm) in the middle and a minimum of 9.8 mm (range 6.0-16.9 mm) at the distal end. Differences between left and right sides were not significant between X-ray and Optosil imprints, nor between left X-ray and right imprints and vice versa at a P-level of 0.001. Radial neck to shaft angle was 167.8 degrees (range 160.5-178 degrees ) measured under image intensification at a rotation angle of 58.6 degrees (range 50-70 degrees ) supination. CONCLUSION: Geometry of the radial neck's intramedullary canal has been described for stem design. The minimum diameter was seen at the distal end, just proximal to the radial tuberosity. A forearm rotation of 58.6 degrees to full supination should be considered during implantation of monopolar prostheses. The wide variety of lengths and diameters complicates standard prosthetic design, but ipsilateral and contralateral X-rays can be useful for preoperative stem size calculation.