Marked Subchondral Bandlike Osteopenia on Radiography after Trauma and Inactivity: A Report of four Cases.

We report about four cases of marked subchondral osteopenia on followup radiography after trauma and prolonged disuse. This localized form of disuse osteopenia has not been reported in details beside the followup imaging of talar neck fractures, where it is known as the "Hawkins sign." Due to its unique morphology, it can be easily recognized as a benign finding in posttraumatic followup imaging and can be morphologically distinguished from severe complications like complex regional pain syndrome type 1 (Sudeck's disease) or periarticular osteopenia in infectious arthritis. It is important for the radiologist and orthopaedic surgeon to be aware of this form of disuse osteopenia in the proper clinical context.

[Mesh shrinkage in hernia surgery: data from a prospective randomized double-blinded clinical study]. / Netzschrumpfung in der Hernienchirurgie : Ergebnisse einer klinischen, prospektiv-randomisierten Doppelblindstudie.

OBJECTIVES: According to an estimated mesh shrinkage following hernia repair of up to 40% a current dogma in hernia surgery requires a mesh overlap of 5 cm around the hernia. However, no valid data addressing this problem of mesh shrinkage are available at present. PATIENTS AND METHODS: Within the framework of a prospective randomized double-blinded clinical trial, 50 patients were operated on for a ventral abdominal hernia with the open sublay technique using specially prepared radio-opaque polypropylene (PP) meshes. Of the patients 27 received a conventional heavyweight mesh (P group) and 23 a new lightweight mesh construction (NK group). Follow-up for at least 2 years after mesh repair included conventional abdominal x-rays after 7 days, 3 weeks and 4, 12 and 24 months, as well as computed tomography after 7 days and 4 and 12 months. Main criteria were mesh shrinkage, recurrence and complication rates and quality of life comparing groups P and NK. RESULTS: In 46 cases (92%) no mesh shrinkage could be detected and only 4 meshes (8%) showed a moderate shrinkage (1 of 22.2%, 2 of 8% and 1 of 3%) all from the P group. While no hernia recurrences were found, 2 surgical complications occurred with 1 seroma in the P group and 1 hematoma in the NK group. Quality of life showed a linear improvement over time up to the 2 year time point following mesh repair with advantages for the NK group. Pain and mobility scores reached standard values 12 months postoperatively without significant differences between the two groups. CONCLUSIONS: In principle PP meshes following an uncomplicated ventral hernia repair do not shrink at all. A moderate shrinkage in isolated cases might occur following heavyweight mesh implantation. Under controlled conditions recurrence as well as complication rates are equal for heavyweight and lightweight PP meshes. Quality of life improves up to 2 years following mesh repair with a trend to a better outcome for lightweight meshes. Pain and mobility scores reached standard values 12 months postoperatively without significant differences between the lightweight and heavyweight meshes.

Axial rotation in the lumbar spine following axial force wrench.

The report presents measurements of axial rotation of lumbar motion segments (L1/L2, L3/L4, L4/L5), particularly with small angles of rotation (in the range of +/-1 degrees) following axial force wrenches. The investigation focussed on determining the influence of geometrically varying configurations in axial wrench (consisting of axial torque and axial force) applied on the kinematics (as defined by the migrating instantaneous helical axis, IHA) of lumbar motion segments under constant resulting axial force, and relating IHA-migration to anatomical structures. In all segments, IHA migrated over several centimetres (up to 6 cm). The main portion of IHA-migration was linked to the angle of rotation interval of +/-1 degrees. 3. The shape of the IHA-migration was greatly dependent upon the position of the force line F(z). The-force-wrench-dependent wide IHA-migration found for the rotational angle interval of +/-1 degrees suggests that joint guidance predominates in segment kinematics. The segment kinematics can be adjusted by means of the geometrical configuration of the force wrenches. The design of non-fusion spine implants and FE calculations have to take into consideration joint guidance and muscular force distributions with small intervals of axial rotation.

virtX - evaluation of a computer-based training system for mobile C-arm systems in trauma and orthopedic surgery.

OBJECTIVES: Operating room personnel (ORP) operating mobile image intensifier systems (C-arms) need training to produce high quality radiographs with a minimum of time and X-ray exposure. Our study aims at evaluating acceptance, usability and learning effect of the CBT system virtX that simulates C-arm based X-ray imaging in the context of surgical case scenarios. METHODS: Prospective, interventional study conducted during an ORP course with three groups: intervention group 1 (training on a PC using virtX), and 2 (virtX with a C-arm as input device), and a control group (training without virtX) - IV1, IV2 and CG. All participants finished training with the same exercise. Time needed to produce an image of sufficient quality was recorded and analyzed using One-Way-ANOVA and Dunnett post hoc test (alpha = .05). Acceptance and usability of virtX have been evaluated using a questionnaire. RESULTS: CG members (n = 21) needed more time for the exercise than those of IV2 (n = 20): 133 +/- 55 vs. 101 +/- 37 sec. (p = .03). IV1 (n = 12) also performed better than CG (128 +/- 48 sec.), but this was not statistically significant. Seventy-nine participants returned a questionnaire (81% female, age 34 +/- 9 years, professional experience 8.3 +/- 7.6 years; 77% regularly used a C-arm). 83% considered virtX a useful addition to conventional C-arm training. 91% assessed virtual radiography as helpful for understanding C-arm operation. CONCLUSIONS: Trainees experienced virtX as substantial enhancement of C-arm training. Training with virtX can reduce the time needed to perform an imaging task.

Bilateral thoracic extraadrenal myelolipoma.

Myelolipoma commonly occurs in the adrenal gland and is composed of both adipose tissue and normal hematopoietic elements. Extraadrenal myelolipoma may occur in the retroperitoneum, stomach, liver, lung, and in 3% of cases even in the mediastinum. We present a 65-year-old female patient with unspecific clinical symptoms. Routine chest roentgenograms revealed bilateral widening of the posterior mediastinum. Computed tomography showed bilateral, paravertebral lesions of 4.5 and 6.5 cm in diameter, respectively. After surgical removal, bilateral thoracic myelolipoma was pathomorphologically diagnosed. The imaging differential diagnosis of bilateral solid lesions in the posterior mediastinum including lymph node metastases, lymphomas, neurogenic tumors and extramedullary hematopoietic tumors is discussed.

[Intramural hematomas of the aorta]. / Intramurale Hämatome der Aorta.

Intramural hematomas (IMH) are regarded as a hemorrhage into the aortic wall. In general a traumatic form can de differentiated from a spontaneous non-traumatic. There is a predisposition of IMH with arterial hypertension and mesoectodermal dysplastic syndromes. The diagnosis is established with the clinical presentation in combination with the findings of different imaging modalities. Acute and subacute discomfort associated with a tendency of collaps are considered as typical presenting complaints. A semicircular or concentric thickening of the aortic wall with the absence of blood flow or a dissection membrane are typical findings in transesophageal echocardiography, computed tomography and magnetic resonance tomography. From a differential diagnostic point of view a distinction from atherosclerotic wall changes, intraluminal thrombi and inflammatory aortic diseases is essential. The IMH is considered as an early presentation of aortic dissection, put into and treated according to the Stanford classification. In the course of natural history an IMH can disappear, rupture or progress into a classic aortic dissection.

MR-guided localization of suspected breast lesions detected exclusively by postcontrast MRI.

OBJECTIVE: We describe and evaluate a preoperative MRI localization procedure for suspected breast lesions. MATERIALS AND METHODS: Fourteen consecutive patients underwent MR localization of suspected breast lesions discovered with contrast-enhanced MRI but not detected by conventional mammography or ultrasound. In each case diagnostic MRI was repeated after the application of special skin markers. A non-magnetic wire was subsequently inserted into the breast and a second MRI performed to document the position of the wire tip relative to the lesion. RESULTS: The procedure was successful in all 14 patients, enabling excision of the lesion and allowing histological diagnoses. CONCLUSION: We found the described procedure to be quite useful.