[Precision and safety of positioning pedicle screws in the thoracic and lumbar spine using a hand-guided aiming sleeve : A CT control study]. / Präzision und Sicherheit der Positionierung von Pedikelschrauben in der Brust- und Lendenwirbelsäule mittels handgeführter Zielhülse : Eine computertomographische Kontrollstudie.

BACKGROUND: For the implantation of pedicle screws, navigation-supported systems are nowadays used more and more to avoid screw misalignment by making the direction of the screw more predictable. OBJECTIVE: Examination of the precision after instrumentation of the pedicle screw with the hand-guided aiming sleeve. The aim was to verify that the implementation of the pedicle screws is plannable and precise by using 2D X­ray only. METHOD: This retrospective study analyzed 27 consecutive trauma patients (17-84 years, 13f/14m) with vertebral body fractures. The position and precision of 108 screws, implanted using the hand-guided aiming sleeve was investigated. To determine the position the actual course of the screws was examined using the postoperative 3D CT data set (GE Optima 540, General Electric Company Boston, MA, USA; slice thickness 1.25 mm). The screws were then compared to the previously defined ideal position of the tip of the screw. In addition to the absolute and relative deviation from the ideal target point, the convergence angle and the parallelism to the cover plate were determined. RESULTS: Of 108 implanted pedicle screws, 90 (83%) were within target. The remaining 18 (17%) represented a clinically irrelevant screw deviation: A lateral deviation was found in 17 pedicle screws (16%) and a medial deviation in 1 (1%). The average deviation from the ideal target point in the vertebral body was 2.3 mm ventrally with a standard deviation of ±â€¯2.3 mm. No screw misalignment or pedicle perforation was found. CONCLUSION: The transcutaneous implantation of pedicle screws with a hand-guided aiming sleeve in the thoracic and lumbar spine represents a safe and precise procedure. The risk of misalignment needing a revision is lower compared to other methods of navigated screw implantation reported in the literature [1-6]. A CT-based preliminary planning is not necessary. The method is economical, special technical equipment is not required.

Improvement of Orthopedic Residency Programs and Diversity: Dilemmas and Challenges, an International Perspective.

BACKGROUND: To date, little has been published comparing the structure and requirements of orthopedic training programs across multiple countries. The goal of this study was to summarize and compare the characteristics of orthopedic training programs in the U.S.A., U.K., Canada, Australia, Germany, India, China, Saudi Arabia, Russia and Iran. METHODS: We communicated with responders using a predetermined questionnaire regarding the national orthopedic training program requirements in each respondent's home country. Specific items of interest included the following: the structure of the residency program, the time required to become an orthopedic surgeon, whether there is a log book, whether there is a final examination prior to becoming an orthopedic surgeon, the type and extent of faculty supervision, and the nature of national in-training written exams and assessment methods. Questionnaire data were augmented by reviewing each country's publicly accessible residency training documents that are available on the web and visiting the official website of the main orthopedic association of each country. RESULTS: The syllabi consist of three elements: clinical knowledge, clinical skills, and professional skills. The skill of today's trainees predicts the quality of future orthopedic surgeons. The European Board of Orthopedics and Traumatology (EBOT) exam throughout the European Union countries should function as the European board examination in orthopedics. We must standardize many educational procedures worldwide in the same way we standardized patient safety. CONCLUSION: Considering the world's cultural and political diversity, the world is nearly unified in regards to orthopedics. The procedures (structure of the residency programs, duration of the residency programs, selection procedures, using a log book, continuous assessment and final examination) must be standardized worldwide, as implemented for patient safety. To achieve this goal, we must access and evaluate more information on the residency programs in different countries and their needs by questioning them regarding what they need and what we can do for them to make a difference.

Exercise Training Adds Cardiometabolic Benefits of a Paleolithic Diet in Type 2 Diabetes Mellitus.

Background The accumulation of myocardial triglycerides and remodeling of the left ventricle are common features in type 2 diabetes mellitus and represent potential risk factors for the development of diastolic and systolic dysfunction. A few studies have investigated the separate effects of diet and exercise training on cardiac function, but none have investigated myocardial changes in response to a combined diet and exercise intervention. This 12-week randomized study assessed the effects of a Paleolithic diet, with and without additional supervised exercise training, on cardiac fat, structure, and function. Methods and Results Twenty-two overweight and obese subjects with type 2 diabetes mellitus were randomized to either a Paleolithic diet and standard-care exercise recommendations ( PD ) or to a Paleolithic diet plus supervised exercise training 3 hours per week ( PD - EX ). This study includes secondary end points related to cardiac structure and function, ie, myocardial triglycerides levels, cardiac morphology, and strain were measured using cardiovascular magnetic resonance, including proton spectroscopy, at baseline and after 12 weeks. Both groups showed major favorable metabolic changes. The PD - EX group showed significant decreases in myocardial triglycerides levels (-45%, P=0.038) and left ventricle mass to end-diastolic volume ratio (-13%, P=0.008) while the left ventricle end-diastolic volume and stroke volume increased significantly (+14%, P=0.004 and +17%, P=0.008, respectively). These variables were unchanged in the PD group. Conclusions Exercise training plus a Paleolithic diet reduced myocardial triglycerides levels and improved left ventricle remodeling in overweight/obese subjects with type 2 diabetes mellitus. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01513798.

Fracture Statistics for Inorganically-Bound Core Materials.

In this article, we study the fracture characteristics of inorganically-bound foundry cores. It will be shown that the fracture stress of inorganic cores follows Weibull's strength distribution function for brittle materials. Using three-point and four-point-bending experiments, the volume dependence of the bending fracture stress is analyzed and a Weibull model fitted. Furthermore, the fracture stress of arbitrary bending experiments can be calculated based on the Weibull parameters found.

Early results of a posterolateral polyaxial angle-stable plate for tibiotalocalcaneal arthrodesis.

Tibiotalocalcaneal arthrodesis is still considered the reference standard therapy for salvage of severe osteoarthritic deformities of the ankle and hindfoot. Because of the unique anatomy and biomechanics of the ankle, even minor injuries can progress to end-stage osteoarthritis over time. This can be debilitating to patients' general health and physiologic ambulation. Arthrodesis aims to correct the misalignment and should comply with Glissan's principles (i.e., maintenance of permanent stability and sound compression between the fused elements). Several different surgical techniques have been described in the international medical literature. Intramedullary nails can create and maintain a stable condition but lack the necessary compression. Screw fixation can generate compression but might not yield enough stability until sound union has been achieved. In the present study, we report the early results of an innovative posterolateral polyaxial angle-stable plate that combines the features that address all the principles of arthrodesis in 1 device.

Enhancement of bone formation in hydroxyapatite implants by rhBMP-2 coating.

The combination of hydroxyapatite (HA) implants serving as osteoconductive scaffold with growth factors is an interesting approach for the improvement of bone defect healing. The purpose of this study was to test whether recombinant human bone morphogenetic protein-2 (rhBMP-2) coating of solid HA-implants improves bone formation in a cortical bone defect. Cylindrical trephine mill defects (diameter: 9.8 mm, depth: 10 mm) were created into the cortical tibia shaft of minipigs and subsequently filled either by plain HA cylinders (Endobon) or by rhBMP-2-coated HA cylinders. Fluorochrome labeling for the evaluation of time-dependent bone formation was done on days 8, 9, and 10 postsurgery with tetracyclin-100, at days 25 and 30 with alizarin-komplexon, and finally on days 32, 37, 73, and 79 with calcein green. Twelve weeks after implantation, the tibiae were harvested and were prepared for standard histological staining, fluorochrome analysis, and histomorphometry. Coating of HA implants with rhBMP-2 led to significant enhanced new bone formation of 84.7% (+/-4.6%) of the implant area with almost complete bony incorporation compared with only 27.7% (+/-8.5%) in the uncoated HA implants (p = 0.028). In both types of implants, osteoconduction of HA led to bone ingrowth of the surrounding host bone into the implants. However, only rhBMP-2-coated implants showed multitopic de novo bone formation reflecting the osteoinductive properties of rhBMP-2 in all areas of the HA implant. This study showed that the coating of HA ceramic implants with rhBMP-2 can significantly enhance new bone formation attributable to its osteoinductive effects.

Derotation of post-traumatic femoral deformities by closed intramedullary sawing.

Different techniques and devices have been used for correction osteotomies of bones in patients with malalignments. The most frequently used technique for rotational deformities of the femur and tibia is open osteotomy with an oscillating saw and pre-drilled holes with all well-known drawbacks of open surgery. An intramedullary device with an adapted minimal-invasive surgical technique allows intramedullary osteotomy of the bone preserving the surrounding soft tissue. We performed femoral osteotomies with an intramedullary saw followed by static interlocking nailing in 14 patients with post-traumatic rotational deformity in the femur. Twelve patients had an external rotational deformity of the femur ranging between 26 and 63 degrees , one had an additional leg-shortening of about 4 cm. Two patients had internal rotational deformities. In two patients with delayed fracture healing union was achieved within one year without secondary surgery. Post-operative clinical assessment and CT-scans revealed good derotation results with deformities of less than 4 degrees in all cases. No device-related complications were observed. Therefore, we conclude that "closed" osteotomy with an intramedullary saw is a minimal-invasive, safe and reliable option for derotation procedures in the femur.

Glycerol-l-lactide coating polymer leads to delay in bone ingrowth in hydroxyapatite implants.

Glycerol-l-lactide as coating polymer for the delivery of basic fibroblast growth factor (bFGF) from hydroxyapatite (HA) ceramic implants was shown to lead to significant delay in bone ingrowth into the implants compared to implants without the coating polymer. The purpose of this work was to study bone ingrowth in HA ceramic implants with and without the coating polymer but without growth factors to enable differentiation between a locking effect of the pores by the polymer and the fact of inactivation of the growth factors by the polymer, which could both be possible for the delay. A defect was created in the subchondral region of both femurs in 24 miniature-pigs and was either filled by the HA implants with or without the coating polymer. Histomorphometry showed a significant delay in bone ingrowth in the polymer coated implants both after 6 and 12 weeks. Detailed histology revealed that the HA pores were completely "locked" by the polymer leading to complete loss of the osteoconductive properties of the HA. Also electron microscopy showed filling of the HA pores by the polymer. Therefore, it can be concluded that glycerol-l-lactide should not be used to coat HA ceramic implants due to significant delay in bone ingrowth.

Frequency and effects of intratendinous and peritendinous calcifications after open Achilles tendon repair.

BACKGROUND: Although calcification of the Achilles tendon has been described by several authors, a detailed evaluation of its frequency and effects on clinical outcome has not been reported. The purposes of this work were to determine the frequency of calcifications in the Achilles tendon after open repair and their effects on clinical outcomes and to identify possible risk factors for postoperative calcification. METHODS: Thirty-six patients with open Achilles tendon repair were evaluated at an average followup of 19 months. Evaluation included a self-assessment questionnaire concerning treatment outcomes, clinical examination, and radiographic and ultrasonographic examinations. RESULTS: No patient had calcifications in the Achilles tendon area before surgery. Postoperatively, intratendinous or peritendinous calcifications, ranging in size from 3 mm to 37 mm, were found in 10 (28%) of the 36 patients. The development of calcifications was associated with chronic swelling, decreased range of motion of the ankle joint, and increase pain, especially with calcifications larger than 10 mm. No association was found between the development of calcifications and the surgical technique, suture materials, time from injury to surgery, or postoperative management, and no risk factors could be identified. CONCLUSIONS: Calcifications of the Achilles tendon appear to be frequent after open tendon repair and to have a negative effect on clinical outcome.

Effect of glycerol-L-lactide coating polymer on bone ingrowth of bFGF-coated hydroxyapatite implants.

Basic fibroblast growth factor (bFGF)-coated hydroxyapatite (HA) cylinders showed good bony incorporation in a previously conducted animal study. However, some cylinders exhibited focal inhomogeneous bone ingrowth. The purpose of the current study was to test whether glycerol-L-lactide polymer coating could improve release properties and bone incorporation of bFGF-coated HA implants. bFGF-coated HA cylinders with or without coating polymer were investigated for in vitro release of bFGF by an immuno-ligand-assay and also for bone ingrowth in miniature pigs after 42 and 84 days. Release from bFGF polymer composites was lower for the first 3 days compared to the other group but was more homogenous and detectable amounts were still found after 20 days. There was significant delay in bone ingrowth of the polymer implants in which even after 84 days bone ingrowth was not completed, whereas in the other group incorporation after 42 days occurred. Detailed histology revealed filling of the HA pores with the polymer, making ingrowth of the surrounding host bone impossible. Only after 84 days starting resorption of the polymer accompanied by bone ingrowth was found. The current study showed that glycerol-L-lactide is not suitable for coating of HA implants due to polymer induced "locking" of HA pores.

Sonographic detection of an isolated cuboid bone fracture not visualized on plain radiographs.

We report the case of an isolated cuboid bone fracture in a child that was missed on radiography but was diagnosed on sonography. Plain radiographs of the patient's right foot showed no fracture, whereas sonograms demonstrated a fracture of the cuboid bone that appeared as a steplike discontinuity in the cortical bone. The diagnosis was confirmed on MRI. The fracture was treated with cast immobilization and no weight bearing for 4 weeks. In 8 weeks, the patient had no symptoms and good motor and sensory function of her right foot. Other imaging modalities are usually advocated for diagnosing fractures that are missed by radiography. Over the last decade, sonography has been increasingly used for diagnosing occult fractures. Although its use in such cases is not yet fully established, we believe that in the future, the sonographic detection of an injury that corresponds to the site of the reported pain will be adequate for initiating treatment of many types of fractures.

PMMA vertebroplasty in patients with malignant vertebral destruction of the thoracic and lumbar spine.

OBJECT: Patients with osteolytic metastases frequently suffer from serious local and radicular pain. Pathophysiologically, local pain arises from skeletal instability, whereas radicular pain originates from compression of nerve roots by local tumor growth. Causal treatment of osteolytic metastases in disseminated malignant disease is very difficult. Resection of vertebrae, in combination with ventro-dorsal stabilization, is a complex treatment for patients with a limited life expectancy. Percutaneous polymethylmethacrylate (PMMA) vertebroplasty is a new and easy method of relieving patients' pain. In addition, it is both cost effective and safe. Pain is reduced immediately after treatment. Due to the regained vertebral stability, early mobilization of the patients is possible. METHODS: A total of 22 patients with osteolytic malignancies of the thoracic and lumbar spine were treated with PMMA vertebroplasty. Prior to and after surgery, then six weeks and six months after discharge from hospital, patients answered the Oswestry Low Back Pain Disability (OLBPD) Questionnaire for assessment of treatment-related change in disability. Percutaneous vertebroplasty was performed in a total of 19 patients. In three patients with tumor related compression of nerve roots an open neurolysis was performed followed by vertebroplasty. RESULTS: A total of 86% of patients reported a significant pain reduction. Vertebroplasty was highly beneficial for patients with pain related to local instability of the spine, but less so in patients with additional nerve root compression. Extravasation of PMMA beyond the vertebral margins was observed in 23% of the cases. No treatment-related clinical or neurological complications were seen. CONCLUSIONS: PMMA vertebroplasty is a useful and safe method of pain relief for patients with malignant osteolytic diseases of the thoracic and lumbar spine.