Percutaneous screw fixation of the iliosacral joint: A case-based preoperative planning approach reduces operating time and radiation exposure.

INTRODUCTION: A preoperative planning approach for percutaneous screw fixation of the iliosacral joint provides specific entry points (EPs) and aiming points (APs) of intraosseous screw pathways (as defined by CT scans) for lateral fluoroscopic projections used intraoperatively. The potential to achieve the recommended EPs and APs, to obtain an ideal screw position (perpendicular to the iliosacral joint), to avoid occurrence of extraosseous screw misplacement, to reduce the operating time and the radiation exposure by utilizing this planning approach have not been described yet. METHODS: On preoperative CT scans of eight human cadaveric specimen individual EPs and APs were identified and transferred to the lateral fluoroscopic projection using a coordinate system with the zero-point in the center of the posterior cortex of the S1 vertebral body (x-axis parallel to upper S1 endplate). Distances were expressed in relation to the anteroposterior distance of the S1 upper endplate (in%). In each specimen on one side a screw was placed with provided EP and AP (New Technique) whereas at the contralateral side a screw was placed without given EP and AP (Conventional Technique). Both techniques were compared using postoperative CT scans to assess distances between predefined EPs and APs and the actually obtained EPs and APs, screw angulations in relation to the iliosacral joint in coronal and axial planes and the occurrence of any extraosseous screw misplacement. The "operating time (OT)" and the "time under fluoroscopy (TUF)" were recorded. Statistical analysis was performed by the Wilcoxon signed-rank test. RESULTS: EPs were realized significantly more accurate using the new technique in vertical direction. The screw positions in relation to the iliosacral joint showed no significant difference between both techniques. Both techniques had one aberrantly placed screw outside the safe corridor. The (mean±SD) "OT" and the (mean±SD) "TUF" were significantly decreased using the new technique compared to the conventional technique (OT: 7.6±2min versus 13.1±5.8min, p=0.012; TUF: 1.5±0.8min versus 2.2±1.1min). CONCLUSION: The presented preoperative planning approach increases the accuracy in percutaneous screw fixation of the iliosacral joint, reduces operating time and minimizes radiation exposure to patient and staff.

[Cost effectiveness of GnRH antagonists in patients with prostate cancer and cardiovascular risk : Comparative analysis against Leuprorelin by the Number Needed to Treat]. / Kosteneffektivität von GnRH-Antagonisten bei Patienten mit Prostatakarzinom und kardiovaskulärem Risiko : Vergleichende Analyse gegenüber Leuprorelin anhand der Number Needed to Treat.

BACKGROUND: Recent studies suggest that androgen deprivation therapy (ADT) is associated with increased cardiovascular (CV) risk for patients with hormone-sensitive prostate cancer (PCa) and pre-existing CV disease. This risk seems to be different for the gonadotropin-releasing hormone (GnRH) agonists leuprolide and goserelin and GnRH antagonists, whereas the slightly more expensive GnRH antagonist shows a beneficial risk profile. The present study assesses the cost effectiveness of degarelix compared to leuprolide for PCa patients with increased CV risk. METHODS: This analysis is based on a pooled analysis of six phase III, randomized, controlled trials comparing the GnRH agonists leuprolide and goserelin with the GnRH antagonist degarelix. For the combined endpoint of CV events or death a superiority of degarelix was determined with a Number-Needed-to-Treat of 12. From the perspective of German statutory health insurance, this evaluation estimates and compares the additional drug costs of degarelix treatment to the cost of one (avoided) CV event. The CV event costs were estimated via emergency treatment and transportation, inpatient treatment, and rehabilitation. The difference of these two cost pools divided by 12 yields the average saving per patient and year. RESULTS: For every 12 PCa patients with CV history that are treated with GnRH antagonists to prevent one CV event, there will be additional drug costs in comparison with leuprolide treatment of € 3111 per year. Costs of € 8447 per year are prevented. Therefore, each patient with a history of CV who is treated with degarelix instead of a leuprolide generates savings of € 445 per patient and year. CONCLUSIONS: Compared to leuprolide, degarelix is cost effective for patients with increased CV risk.

Biomechanical validation of computer assisted planning of periacetabular osteotomy: A preliminary study based on finite element analysis.

Periacetabular Osteotomy (PAO) is a joint preserving surgical intervention intended to increase femoral head coverage and thereby to improve stability in young patients with hip dysplasia. Previously, we developed a CT-based, computer-assisted program for PAO diagnosis and planning, which allows for quantifying the 3D acetabular morphology with parameters such as acetabular version, inclination, lateral center edge (LCE) angle and femoral head coverage ratio (CO). In order to verify the hypothesis that our morphology-based planning strategy can improve biomechanical characteristics of dysplastic hips, we developed a 3D finite element model based on patient-specific geometry to predict cartilage contact stress change before and after morphology-based planning. Our experimental results demonstrated that the morphology-based planning strategy could reduce cartilage contact pressures and at the same time increase contact areas. In conclusion, our computer-assisted system is an efficient tool for PAO planning.

Rationales for the Bernese approaches in acetabular surgery.

PURPOSE: To present two new approaches to acetabular surgery that were established in Berne, and which aim at enhanced visualization and anatomical reconstruction of acetabular fractures. METHOD: The trochanteric flip osteotomy allows for surgical hip dislocation, and was introduced as a posterior approach for acetabular fracture management involving the posterior column and wall. For acetabular fractures predominantly involving the anterior column and the quadrilateral plate, the Pararectus approach is described. RESULTS: Full exposure of the hip joint, as provided by the trochanteric flip osteotomy, facilitates anatomical reduction of acetabular or femoral head fractures and safe positioning of the anterior column screw in transverse or T-shaped fractures. Additionally, the approach enables osteochondral transplantation as a salvage procedure for severe chondral femoral head damage and osteoplasty of an associated inadequate offset at the femoral head-neck junction. The Pararectus approach allows anatomical restoration with minimal access morbidity, and combines advantages of the ilioinguinal and modified Stoppa approaches. CONCLUSIONS: Utilization of the trochanteric flip osteotomy eases visualization of the superior aspect of the acetabulum, and enables the evaluation and treatment of chondral lesions of the femoral head or acetabulum and labral tears. Displaced fractures of the anterior column with a medialized quadrilateral plate can be addressed successfully through the Pararectus approach, in which surgical access is associated with minimal morbidity. However, long-term results following the two presented Bernese approaches are needed to confirm that in the treatment of complex acetabular fractures the rate of poor results in almost one-third of all cases (as currently yielded using traditional approaches) might be reduced by the utilization of the presented novel approaches.

The Pararectus approach for anterior intrapelvic management of acetabular fractures: an anatomical study and clinical evaluation.

A new anterior intrapelvic approach for the surgical management of displaced acetabular fractures involving predominantly the anterior column and the quadrilateral plate is described. In order to establish five 'windows' for instrumentation, the extraperitoneal space is entered along the lateral border of the rectus abdominis muscle. This is the so-called 'Pararectus' approach. The feasibility of safe dissection and optimal instrumentation of the pelvis was assessed in five cadavers (ten hemipelves) before implementation in a series of 20 patients with a mean age of 59 years (17 to 90), of whom 17 were male. The clinical evaluation was undertaken between December 2009 and December 2010. The quality of reduction was assessed with post-operative CT scans and the occurrence of intra-operative complications was noted. In cadavers, sufficient extraperitoneal access and safe instrumentation of the pelvis were accomplished. In the patients, there was a statistically significant improvement in the reduction of the fracture (pre- versus post-operative: mean step-off 3.3 mm (sd 2.6) vs 0.1 mm (sd 0.3), p < 0.001; and mean gap 11.5 mm (sd 6.5) vs 0.8 mm (sd 1.3), p < 0.001). Lesions to the peritoneum were noted in two patients and minor vascular damage was noted in a further two patients. Multi-directional screw placement and various plate configurations were feasible in cadavers without significant retraction of soft tissues. In the treatment of acetabular fractures predominantly involving the anterior column and the quadrilateral plate, the Pararectus approach allowed anatomical restoration with minimal morbidity related to the surgical access.

[Minimally invasive unicondylar knee arthroplasty with simultaneous ACL reconstruction : treatment of medial compartment osteoarthritis and cruciate ligament defect]. / Mediale Gonarthrosen mit Kreuzbanddefekt : Kombinierte Versorgung mittels unikondylärer Endoprothese und additivem Kreuzbandersatz.

BACKGROUND: Low postoperative pain level, decreased length of hospital stay and accelerated rehabilitation are the major benefits of unicondylar knee arthroplasty. Especially in comparably young, not yet retired and still active patients with an isolated medial gonarthrosis, these prostheses offer many advantages. However, one important requirement to be treated with such implants is a well functioning stability system of the muscles and ligaments. Thus in patients with degenerated or destroyed anterior cruciate ligaments it is contraindicated to use this method. In order to still take advantage of this therapy for treatment of isolated arthrosis, reestablishment of the proprioceptive structures through simultaneous or staged ACL reconstruction is mandatory. PATIENTS AND METHODS: Pursuing this goal we performed unicondylar knee arthroplasty with simultaneous ACL reconstruction on eligible patients. Between 2003 and 2006 we treated 32 knees with this combined surgery and followed them for a mean of 31 months (range: 10-38). RESULTS: The mean Knee Society Score significantly improved from 83.2 (44-103) to 167.6 (145-177) at a mean follow-up of 31 months (10-38). CONCLUSIONS: Preliminary results of this short-term follow-up are promising. Especially the predominant number of patients who were able to return to work soon after rehabilitation and the significantly improved score postoperatively reflect the benefits of this prosthesis system in select patients. However, long-term follow-up and larger case numbers are necessary to confirm these encouraging results in the future.

Application of surgical navigation to total hip arthroplasty.

Instability, impingement, and leg-length discrepancy are among the most common early problems following total hip arthroplasty (THA). Component positioning is the primary factor affecting all three of these issues and, therefore, all three can be potentially addressed using surgical navigation. While the advent of less invasive surgical techniques performed through smaller incisions has been shown to accelerate recovery, these techniques have also been associated with a further increase in the incidence of these three problems. Acetabular component malpositioning has been a particular problem with less invasive surgical techniques. Nonetheless, it is clear that maximal preservation of the soft tissues around the hip joint may accelerate recovery following surgery and confer greater hip joint stability. Accomplishing these goals without compromising component positioning is the single greatest potential advantage to the application of surgical navigation to THA. The present paper describes the general principles of surgical navigation in THA with respect to methods of tracking, methods of registration, the role of image-free and image-based navigation, and methods of measuring leg-length change during surgery. Further, a description is given of the clinical effect of combining surgical navigation with use of the superior capsulotomy technique of performing THA, which aims maximally to preserve the soft tissues surrounding the hip joint, allowing unrestricted progression of motion and weight-bearing following surgery. These methods have led to statistically significant acceleration of recovery, improvement in acetabular component positioning, and reductions in peri-operative surgical complications.

Effect of 6-hour exposure to 20 degrees C on the ATP content and other biochemical measures of CPDA-1 packed red cells.

Blood donations for clinical use are routinely stored at 2 degrees C to 6 degrees C for 35 to 42 days. It is common practice for RBCs exposed to temperatures above 10 degrees C to be destroyed, although the American Association of Blood Banks Technical Manual states "Blood exposed to temperatures above 10 degrees C is not necessarily unsuitable for transfusion". To clarify this issue we investigated the effect of 6-hour storage at 20 degrees C on the content of ATP and other biochemical measures of CPDA-1 packed red cells. CPDA-1 packed RBC units were exposed once at day 5 (group 1), day 15 (group 2) or day 30 (group 3) of their shelf life to 20 degrees C for 6 hours. Control groups were continuously refrigerated. Under all conditions of storage, the ATP concentrations decreased with time. Initial ATP levels of five-day old CPDA-1 packed RBCs were 3.94 mumol/g Hb in the test group and 3.73 mumol/g Hb in the control group. At day 30 after warming (day 35 of the shelf-life) the ATP concentrations declined to 2.78 mumol/g Hb (test group) and to 3.55 mumol/gHb (controls). In the test series which were warmed at day 15 and day 30 of shelf-life the ATP levels declined to 3.16 mumol ATP/g Hb and 2.92 mumol ATP/g Hb at day 35 of shelf-life. There was no significant difference between test and control group with respect to the lactate levels, whole-blood glucose, sodium and potassium. The percentage of hemolysis was lower than 0.5% under all conditions of storage. Our data show that a shorter period of moderate warming (6h, 20 degrees C) does not lead to a critical decline of ATP and glucose concentrations in CPDA-1 packed RBCs. The survival of RBCs stored in CPDA-1 is most highly correlated with maintaining ATP concentrations above a value of about 2 mumol per g of Hb [3]. The ATP levels in our study were well above this threshold.

Operative tube versus percutaneous cholecystostomy for acute cholecystitis.

The records of 26 patients who underwent cholecystostomy procedures for presumed acute cholecystitis during a 6-year period were reviewed. Nine patients had operative tube cholecystostomy (OC), and 17 patients had radiologic percutaneous cholecystostomy (PC). A correct diagnosis of acute cholecystitis was made in 22 of 26 patients (84%), including 14 of 17 PC patients and 8 of 9 in the OC group. The rate of resolution of cholecystitis was the same in each group (75% OC versus 78% PC). APACHE II scores prior to treatment were significantly higher in OC patients (20.9 OC versus 12.4 PC, p < 0.01). There were 5 deaths, including 3 in the OC groups and 2 in the PC group. Nonfatal complications were more frequent in the PC group. Two of the 14 correctly diagnosed PC patients (14%) subsequently required emergency cholecystectomy for persistent biliary sepsis, and 6 patients (43%) required at least 1 tube exchange for occlusion or dislodgement. Overall, only 5 of the 14 patients (36%) in the PC group were successfully treated without complications compared with 5 of 8 patients (63%) in the OC group. Despite its theoretical advantages, PC was no more effective than OC in the treatment of acute cholecystitis. These data suggest that OC remains a viable treatment option in critically ill patients with acute cholecystitis.

Decreased cardiac concentration of cGMP kinase in hypertensive animals. An index for cardiac vascularization?

Cyclic GMP (cGMP) kinase is intimately involved in the regulation of vascular smooth muscle tone. Its tissue concentration was determined in normotensive and hypertensive rats by use of monospecific anti-cGMP kinase antibodies. Hearts of spontaneously hypertensive rats and renovascular (Goldblatt II) hypertensive rats contained half the concentration of cGMP kinase than those of the respective normotensive animals. The increase in blood pressure and the resulting left ventricular hypertrophy were correlated inversely with the left ventricular cGMP kinase concentration. This decrease was specific for the left ventricle and was not observed in other tissues. In addition, the cardiac concentration of cGMP kinase was unchanged in hyperthyroid animals that had comparable left ventricular hypertrophy and mild hypertension. This suggested that in severe renovascular hypertension the decrease in cardiac cGMP kinase concentration is caused by a relative lack of cardiac vessel growth during the development of hypertrophy. In agreement with this conclusion, immunohistochemistry of cardiac cross sections showed that cGMP kinase was exclusively located in cardiac vessels. In support of this localization, the maximal arterial blood flow of heart, liver, skeletal muscle, and kidney correlated excellently with the cGMP kinase content of the respective organ. These results suggest that the cGMP kinase concentration of nonsmooth muscle tissues depends on the amount of organ-specific vascular smooth muscle and may be used as an index for the vascularization of these organs.

Regulation of cytosolic calcium by cAMP and cGMP in freshly isolated smooth muscle cells from bovine trachea.

The regulation of the cytosolic calcium concentration was investigated in freshly isolated adult bovine tracheal smooth muscle cells using fura 2. These cells contain 1.1 and 1.8 pmol of cGMP kinase and cAMP kinase per mg protein, respectively. Carbachol, histamine, serotonin, isoproterenol, and salbutamol increased the cytosolic calcium in a dose-dependent manner from 79 nM to about 650 nM. Preincubation of these cells for 20 min with isoproterenol, forskolin, 8-Br-cAMP and 8-(4-Cl-phenyl)thio-cAMP did not lower carbachol-induced increases in cytosolic calcium concentration, whereas the phorbol ester 12-O-tetradecanoylphorbol 13-acetate, the atrionatriuretic factor, isobutylmethylxanthine, and 8-Br-cGMP lowered cytosolic calcium. The active fragment of cGMP kinase, but not the catalytic subunit of cAMP kinase lowered carbachol-induced calcium levels. Carbachol released calcium from intracellular stores and increased calcium influx from the extracellular space. The influx was inhibited by preincubation with the calcium channel blockers nitrendipine or gallopamil. Both carbachol-stimulated pathways were suppressed by 8-Br-cGMP. Isoproterenol increased only the influx of calcium from the outside by a channel which was blocked by calcium channel blockers or 8-Br-cGMP. Forskolin and 8-Br-cAMP lowered carbachol- and isoproterenol-stimulated increases in calcium when added shortly before or after the addition of the agonist. In addition, isoproterenol decreased carbachol-stimulated calcium levels when added 10 s after carbachol. The calcium stimulatory effect of isoproterenol was abolished by preincubation of the cells with pertussis toxin or cholera toxin. These results show (a) that the beta 2-adrenoceptor couples in isolated tracheal smooth muscle cells to a dihydropyridine- and pertussis toxin-sensitive calcium channel; (b) that the same channel is opened by carbachol; (c) that cGMP kinase is very effective in decreasing elevated cytosolic calcium concentrations, whereas cAMP-dependent protein kinase has a variable effect on stimulated cytosolic calcium levels.