Radiographic analysis of a hand-held surgical navigation system for tibial resection in total knee arthroplasty

Tibial intramedullary or extramedullary alignment guides have not been shown to be highly accurate in performing the tibial resection in total knee arthroplasty (TKA). Since May 2010, a total of 42 knees underwent a TKA using a hand-held, accelerometer-based surgical navigation system for performing the tibial resection (KneeAlign; OrthAlign Inc, Aliso Viejo, Calif). Postoperative standing anteroposterior hip-to-ankle and lateral knee-to-ankle radiographs demonstrated that 97.6% of the tibial components were placed within 90° ± 2° to the mechanical axis in the coronal plane, and 96.2% of the components were placed within 3° ± 2° to the mechanical axis in the sagittal plane. The KneeAlign greatly improves the accuracy of tibial component alignment in TKA.     

Lengthening of the femur over an existing intramedullary nail

Leg length discrepancies can occur despite successful union of femur fractures after intramedullary nailing (IMN). Often, the leg length discrepancy can result in significant disability to the patient, altered gait biomechanics, pelvic obliquity, and pain. Therefore, a successful clinical result for such deformities after IMN involves addressing the leg length inequality. Femoral reconstruction with an osteotomy around an existing intramedullary nail was introduced to address axial deformity correction and limb lengthening without changing or removing a previously inserted IMN. This technique uses the principles of lengthening over an IMN. The presence of the nail has minimized the time needed for the external fixator because the nail supports the regenerate bone or osteotomy during the consolidation phase. With this technique, surgery is minimized by avoiding the need for exchange nailing.     

Rapid prototype patient-specific drill template for cervical pedicle screw placement.

OBJECTIVE: To assess the feasibility and accuracy of a drill template for the placement of a cervical pedicle screw in a single vertebral level. MATERIALS AND METHODS: A volumetric CT scan was performed on a cadaver cervical spine. Using computer software, a drill template with a predefined trajectory was constructed that was designed to match the posterior surface of the right side of the fifth cervical vertebra. A physical template was created from the computer model using a rapid prototyping machine. The drill template was used to guide drilling of a pilot hole, and a CT scan was performed to assess the accuracy of this hole. A 3.5-mm diameter pedicle screw was placed in the pilot hole. The spine was then dissected to separate the vertebrae and the trajectory of the screw was visually inspected. RESULTS: The feasibility of this patient-specific rapid prototyping technique was demonstrated. Imaging and visual inspection confirmed accurate placement of the pilot hole and cervical pedicle screw without cortical violation. CONCLUSIONS: The potential use of drill templates to place cervical pedicle screws is promising. Our initial methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the cervical spine.     

High Cardiovascular Risk Profile in Young Patients on the Kidney Transplant Waiting List

BackgroundCardiovascular complications are the leading causes of morbidity and mortality in patients with end-stage renal disease. The risk profile very often contributes to their death while on the waiting list. Most studies have been carried out in older patients with end-stage renal disease, reflecting the general dialysis population. The aim of this study was to analyze the risk profile in young patients with advanced chronic kidney disease on the kidney transplant waiting list.MethodsThis was a retrospective, single-center study of 748 patients on the kidney transplant waiting list at the University Hospital Essen, Germany. Clinical and laboratory parameters were collected between 2015 and 2016.ResultsOf 748 patients (62% male), the median age was 48 years. Hypertension, coronary heart disease, and diabetes mellitus were the leading comorbidities, and their frequency rose significantly with age. Their median laboratory values did not differ significantly depending on age except for albumin. Hyperuricemia was quite common in our population with a prevalence of about 75% in women and 50% in men throughout all age groups. A total of 26.6% of the patients between 18 and 35 years of age had advanced anemia (hemoglobin < 10 g/dL), and thus they were affected most frequently. Elevated C-reactive protein serum levels were observed in 37.2% of the patients. Regarding the lipid profile, we observed that HDL cholesterol was within the normal range in only among 51.9% of men and 44.3% of women.ConclusionsCardiovascular risk factors are quite common in our cohort and affect young patients similarly.     

Radio-frequency tumor ablation: internally cooled electrode versus saline-enhanced technique in an aggressive rabbit tumor model

PURPOSE: To compare two methods of radio-frequency (RF) ablation, saline enhancement technique and internally cooled electrodes, for the treatment of small breast cancers in an animal model--highly aggressive VX2 rabbit tumors surrounded by adipose tissue. MATERIALS AND METHODS: Twenty-seven tumors were implanted into retroperitoneal fat of 14 New Zealand White rabbits. RF ablation was performed with ultrasonographic (US) guidance after tumors had grown to 15 mm. Fourteen tumors in seven animals were treated with internally cooled electrodes (30-mm-tip single electrode, 60 W, 10 min); 13 tumors in seven animals, with saline enhancement (0.5 mL/min of saline, 25-mm tip, 30 W, 10 min). Autopsy and histopathologic assessment were performed 3 weeks after therapy. RESULTS: Real-time US of RF ablation was not possible with either method because of obscuration by the increasing hyperechogenicity of the tumor and the surrounding adipose tissue. Equivalent efficacy was demonstrated with the two methods. Significantly greater complications were observed with the saline technique: Free retroperitoneal fluid was detected in one of seven animals with internally cooled electrodes and in all seven animals with saline enhancement (P <.01). Damage to remote structures such as the kidney, spine muscle, and skin was observed at autopsy in one of seven animals with internally cooled technique versus five of seven with saline enhancement (P <.01). CONCLUSION: Given a lower complication rate and similar treatment efficacy in an animal tumor model, internally cooled RF electrode may be advantageous to adjuvant saline infusion for the minimally invasive treatment of breast tumors.     

Welche vertikale Implantatposition ist die richtige?

Background

In many cases incorrect positioning of implants in the vertical plane can only corrected only by explantation, especially in the aesthetic zone; however, what vertical implant position is correct in order to achieve stable long-term aesthetic and functional results in the anterior and posterior dentition?

Material and methods

In order to answer this question the results of the 9th European Consensus Conference (EuCC) from March 2014 in Cologne under the leadership of the European Association of Dental Implantologists (BDIZ EDI) and a recent literature review were included.

Results

The results are discussed with respect to the resorption behavior of implants under conditions of varying depths of implant insertion.

     

Embedding trees in the rationals

An example is presented of a simple algebraic statement whose truth cannot be decided within the framework of ordinary mathematics, i.e., the statement is independent of the usual axiomatizations of set theory. The statement asserts that every tree-like ordering of power equal to or less than the first uncountable cardinal can be embedded homomorphically into the rationals.     

Studies on the frequency and diagnostic value of hepatomegaly]

In 4 groups of patients (I = 1 621 internistic in-patients, II = 2 073 donors with increased SGPT-values, III = 2 619 after-examined patients with hepatitis, IV = 514 patients of a sanatorium for liver diseases) frequency and diagnostic validity of the symptom enlargement of the liver are tested. The most frequent cause of hepatomegalia is in group I an insufficiency of the right heart. The highest percentage, however, is to be found in liver diseases, then come heart insufficiency, diseases of stomach and gall-bladder, diabetes, rheumatic diseases. In these diseases liver biopsy detects additional changes in many cases. The validity test in the 4 groups yields very different results, dependent on the number of patients and the diagnostic questioning. The symptom hepatomegalia cannot be used as a screening test, but it is of high diagnostic value in the clinical diagnostics.