The effect of intravenous dopamine and dobutamine on blood circulation during a microvascular TRAM flap operation

A study was conducted to assess the effect of intraoperatively administered inotropic agents on blood flow in the recipient and donor vessels, during breast reconstruction with a muscle sparing free TRAM flap. Twenty-one consecutive patients were randomized into 3 groups receiving either dopamine, dobutamine, or placebo. When the flap and all vessels had been fully dissected but not yet divided, the study drug was administered intravenously for 15 minutes. Hemodynamic parameters and transit-time flow of the thoracodorsal and inferior epigastric arteries were monitored.Both dobutamine and dopamine infusions resulted in significant raises in cardiac output and mean arterial pressure. However, while dobutamine resulted in a higher cardiac output (P = 0.001) and a decrease in systemic vascular resistance (P = 0.028), the increase in mean arterial pressure was greater with dopamine (P = 0.002). Only the dobutamine group showed increased blood flow, in both the thoracodorsal (P = 0.043) and the inferior epigastric (P = 0.043) arteries.If vasoactive agents are needed during microvascular anesthesia, dobutamine seems to be more advantageous than dopamine.     

Spatial learning and neurogenesis: Effects of cessation of wheel running and survival of novel neurons by engagement in cognitive tasks

Physical exercise stimulates cell proliferation in the adult dentate gyrus and facilitates acquisition and/or retention of hippocampal‐dependent tasks. It is established that regular physical exercise improves cognitive performance. However, it is unclear for how long these benefits last after its interruption. Independent groups of rats received both free access to either unlocked (EXE Treatment) or locked (No‐EXE Treatment) running wheels for 7 days, and daily injections of bromodeoxyuridine (BrdU) in the last 3 days. After a time delay period of either 1, 3, or 6 weeks without training, the animals were tested in the Morris water maze (MWM) either in a working memory task dependent on hippocampal function (MWM‐HD) or in a visible platform searching task, independent on hippocampal function (MWM‐NH). Data confirmed that exposure of rats to 7 days of spontaneous wheel running increases cell proliferation and neurogenesis. In contrast, neurogenesis was not accompanied by significant improvements of performance in the working memory version of the MWM. Longer time delays between the end of exercise and the beginning of cognitive training in the MWM resulted in lower cell survival; that is, the number of novel surviving mature neurons was decreased when this delay was 6 weeks as compared with when it was 1 week. In addition, data showed that while exposure to the MWM‐HD working memory task substantially increased survival of novel neurons, exposure to the MWM‐NH task did not, thus indicating that survival of novel dentate gyrus neurons depends on the engagement of this brain region in performance of cognitive tasks. © 2015 Wiley Periodicals, Inc.     

Robotic Assistance System for Cone-Beam Computed Tomography-Guided Percutaneous Needle Placement

CardioVascular and Interventional Radiology - The study aimed to evaluate a new robotic assistance system (RAS) for needle placement in combination with a multi-axis C-arm angiography system for...     

Salvage of failed trochanteric and subtrochanteric fractures using a distally fixed, modular, uncemented hip revision stem: 30 patients followed for a mean of 4 years

Background and purpose

Treatment options for failed internal fixation of hip fractures include prosthetic replacement. We evaluated survival, complications, and radiographic outcome in 30 patients who were operated with a specific modular, uncemented hip reconstruction prosthesis as a salvage procedure after failed treatment of trochanteric and subtrochanteric fractures.

Patients and methods

We used data from the Swedish Hip Arthroplasty Register and journal files to analyze complications and survival. Initially, a high proportion of trochanteric fractures (7/10) were classified as unstable and 12 of 20 subtrochanteric fractures had an extension through the greater trochanter. Modes of failure after primary internal fixation were cutout (n = 12), migration of the femoral neck screw (n = 9), and other (n = 9).

Results

Mean age at the index operation with the modular prosthesis was 77 (52–93) years and the mean follow-up was 4 (1–9) years. Union of the remaining fracture fragments was observed in 26 hips, restoration of proximal bone defects in 16 hips, and bone ingrowth of the stem in 25 hips. Subsidence was evident in 4 cases. 1 patient was revised by component exchange because of recurrent dislocation, and another 6 patients were reoperated: 5 because of deep infections and 1 because of periprosthetic fracture. The cumulative 3-year survival for revision was 96% (95% CI: 89–100) and for any reoperation it was 83% (68–93).

Interpretation

The modular stem allowed fixation distal to the fracture system. Radiographic outcome was good. The rate of complications, however—especially infections—was high. We believe that preoperative laboratory screening for low-grade infection and synovial cultures could contribute to better treatment in some of these patients.The failure rate after surgery for extracapsular hip fractures is low. Occasionally, cutout and migration of the femoral neck screw occur regardless of whether a sliding hip screw or an intramedullary nail is used (Stern 2007). Implant failure after open or closed reduction and internal fixation is mostly seen in patients with unstable fracture patterns, poor bone quality, or poor positioning of the internal fixation device (Haidukewych et al. 2001).It is often difficult to find straightforward solutions. For younger patients, a second attempt at osteosynthesis with or without bone grafting may be favored. For elderly patients, prosthetic replacement is attractive, allowing immediate ambulation without fear of further fracture complications (Stern 2007).A salvage procedure converting failed internal fixation to a cemented primary total hip arthroplasty (THA) is challenging due to pre-existing and acquired osteoporosis, deformation of the trochanteric region, and difficulties in obtaining cement pressurization because of cortical screw holes (Zhang et al. 2004). Thus, an uncemented hip revision arthroplasty in these cases would appear attractive. These implants are designed to bypass regions of proximally deficient bone and to obtain stability and fixation in the distal femoral bone where there is good bone stock.There have been few reports on salvage THA with modular revision implants, and the numbers of patients have been limited (n = 10–23) (Laffosse et al. 2007, Talmo and Bono 2008, D’Arrigo et al. 2010, Abouelela 2011, Thakur et al. 2011). We reviewed a series of patients who had been operated with a specific modular, uncemented hip revision arthroplasty for failure of internal fixation of trochanteric and subtrochanteric fractures.     

Next generation coronary CT angiography: in vitro evaluation of 27 coronary stents

Objectives

To evaluate in-stent lumen visibility of 27 modern and commonly used coronary stents (16 individual stent types, two stents at six different sizes each) utilising a third-generation dual-source CT system.

Methods

Stents were implanted in a plastic tube filled with contrast. Examinations were performed parallel to the system's z-axis for all stents (i.e. 0°) and in an orientation of 90° for stents with a diameter of 3.0 mm. Two stents were evaluated in different diameters (2.25 to 4.0 mm). Examinations were acquired with a collimation of 96?×?0.6 mm, tube voltage of 120 kVp with 340 mAs tube current. Evaluation was performed using a medium-soft (Bv40), a medium-sharp (Bv49) and a sharp (Bv59) convolution kernel optimised for vascular imaging.

Results

Mean visible stent lumen of stents with 3.0 mm diameter ranged from 53.3 % (IQR 48.9???56.7 %) to 73.9 % (66.7???76.7 %), depending on the kernel used at 0°, and was highest at an orientation of 90° with 80.0 % (75.6???82.8 %) using the Bv59 kernel, strength 4. Visible stent lumen declined with decreasing stent size.

Conclusions

Use of third-generation dual-source CT enables stent lumen visibility of up to 80 % in metal stents and 100 % in bioresorbable stents.

Key Points

? Blooming artefacts impair in–stent lumen visibility of coronary stents in CT angiography. ? CT enables stent lumen visibility of up to 80 % in metal stents. ? Stent lumen visibility varies with stent orientation and size. ? CT angiography may be a valid alternative for detecting in-stent restenosis.     

A comparison of feasibility and safety of percutaneous fluoroscopic guided thoracic pedicle screws between Europeans and Asians: is there any difference?

Purpose

To directly compare the safety of fluoroscopic guided percutaneous thoracic pedicle screw placement between Caucasians and Asians.

Methods

This was a retrospective computerized tomography (CT) evaluation study of 880 fluoroscopic guided percutaneous pedicle screws. 440 screws were inserted in 73 European patients and 440 screws were inserted in 75 Asian patients. Screw perforations were classified into Grade 0: no violation; Grade 1: <2 mm perforation; Grade 2: 2–4 mm perforation; and Grade 3: >4 mm perforation. For anterior perforations, the pedicle perforations were classified into Grade 0: no violation, Grade 1: <4 mm perforation; Grade 2: 4–6 mm perforation; and Grade 3: >6 mm perforation.

Results

The inter-rater reliability was adequate with a kappa value of 0.83. The mean age of the study group was 58.3 ± 15.6 years. The indications for surgery were tumor (70.3 %), infection (18.2 %), trauma (6.8 %), osteoporotic fracture (2.7 %) and degenerative diseases (2.0 %). The overall screw perforation rate was 9.7 %, in Europeans 9.1 % and in Asians 10.2 % (p > 0.05). Grade 1 perforation rate was 8.4 %, Grade 2 was 1.2 % and Grade 3 was 0.1 % with no difference in the grade of perforations between Europeans and Asians (p > 0.05). The perforation rate was the highest in T1 (33.3 %), followed by T6 (14.5 %) and T4 (14.0 %). Majority of perforations occurred medially (43.5 %), followed by laterally (25.9 %), and anteriorly (23.5 %). There was no statistical significant difference (p > 0.05) in the perforation rates between right-sided pedicle screws and left-sided pedicle screws (R: 10.0 %, L: 9.3 %).

Conclusions

There were no statistical significant differences in the overall perforation rates, grades of perforations, direction of perforations for implantation of percutaneous thoracic pedicle screws insertion using fluoroscopic guidance between Europeans and Asians. The safety profile for this technique was comparable to the current reported perforation rates for conventional open pedicle screw technique.

     

Split‐liver transplantation in the high‐MELD adult patient: are we being too cautious?

The fear that patients with high-mathematical model for end stage liver disease (MELD) score may not be suitable candidates for segmental grafts because of their need for greater liver mass has continued to push the transplant community toward the use of whole LT (WLT) in preference to split LT (SLT). In order to define the outcome of segmental liver transplantation in a better manner in high-MELD patients (score ≥26), we queried the UNOS registry for graft and patient survival results according to MELD score in adult patients receiving WLT and SLT in the United States from the inception of MELD allocation (February 27, 2002) through March 9, 2007. A total of 316 adult patients received a SLT as compared with 20 778 WLTs. Patient and graft survival rates at 6 and 12 months were comparable for all MELD ranges, including the 'high-MELD' recipients (e.g. at MELD score 31–35, patients' and grafts' survival rates at 12 months was 87.5% in SLT group vs. 84.4% and 76.7% in WLT group respectively). The results even at higher MELD scores (i.e. >35) were more than acceptable. In conclusion, patient and graft survival rates for SLT in high-MELD adult patients are comparable to the same for WLT.     

Different osteosyntheses for Colles' fracture: A mechanical study in 42 cadaver bones

Background and purpose In recent years several different plate designs for internal fixation of fractures of the distal radius have been developed. However, few biomechanical studies have been performed to compare these new implants. The purpose of this study was to compare the mechanical properties of 5 different commercially available plates (3 volar and 2 dorsal) with standard K-wire fixation using a distal radial cadaver model.Material and methods 42 human radial bones from 26 cadavers were included. The bone mineral density (BMD) was measured by DEXA in all bones, and the radial bones were assigned to 6 equiv alent groups based on bone density and total amount of mineral. A distal radial osteotomy was done and a dorsal 30-degree wedge of bone was removed. 1 K-wire fixation group and 5 plate groups were tested for rigidity, yield load, and maximum load.Results When data from dorsally and volarly applied plates were pooled, we did not find any statistically significant differences between them regarding stiffness, yield load, and maximum load. The K-wire group showed significantly lower yield load than 3 of the plate groups. There were no statistically significant differences in yield load between the 5 plate groups. The K-wire group showed lower rigidity than the plate groups. The K-wire group and 1 plate group failed at a statistically significant lower maximum load than the 4 other plate groups.Interpretation The volar plates had the same mechanical stability as the dorsally applied plates, and they are therefore a good alternative to dorsally applied plates. K-wire osteosynthesis was inferior to plate osteosyntheses regarding all mechanical properties.     

Evaluation of 4-mm to 7-mm versus 6-mm prosthetic brachial-antecubital forearm loop access for hemodialysis: results of a randomized multicenter clinical trial

OBJECTIVE: Prosthetic arteriovenous fistulas for hemodialysis vascular access have a high incidence rate of thrombotic occlusions that result in graft failure. This randomized multicenter study was performed to assess the patency rates and the effect of 4-mm to 7-mm grafts on the development of stenoses. METHODS: A total of 109 patients who needed vascular access for hemodialysis were randomized to receive either 6-mm (n = 57) or 4-mm to 7-mm prosthetic brachial-antecubital forearm loop accesses (polytetrafluoroethylene). Duplex scanning, with measurement of blood flow and peak systolic velocity and detection of stenoses (>50%), was performed at 1, 6, and 12 months after surgery. Clinical data were obtained in a prospective manner and primary, assisted primary, and secondary patency rates were calculated with the Kaplan-Meier life-table analysis. Statistical analysis was performed with the independent samples t test and chi(2) test. RESULTS: At 1 year, patency rates were similar for both 4-mm to 7-mm and 6-mm prostheses (primary, 46% versus 43%; assisted primary, 62% versus 58%; secondary, 87% versus 91%). The incidence rate of thrombotic occlusion was comparable for both groups (0.74/patient-year versus 0.88/patient-year; P >.05). Mean graft flow at 1, 6, and 12 months was 1416 versus 1415 mL/min, 1345 versus 1319 mL/min, and 1595 versus 1265 mL/min (P >.05) for 4-mm to 7-mm and 6-mm grafts, respectively. Also, no differences in peak systolic velocities in any part of the grafts were observed. The percentage of stenoses detected was equal in both groups at 1 year after surgery (27% versus 20%; P >.05). CONCLUSION: A 4-mm to 7-mm tapered prosthetic brachial-antecubital forearm loop access did not reduce the incidence rates of stenoses and thrombotic occlusions compared with a 6-mm prosthetic conduit. Moreover, no differences in patency rates were observed. Therefore, we believe that the 4-mm to 7-mm graft should not be used routinely for hemodialysis vascular access.     

Brain death induces inflammation in the donor intestine

BACKGROUND: Brain death donors are frequently used for transplantation. Previous studies showed that brain death (BD) negatively affects the immunological and inflammatory status of both liver and kidney. Because the intestine is increasingly used as a donor organ and no information on effects of BD on small intestine is available we performed this study. METHODS: We studied the inflammatory and apoptotic changes in donor intestine after BD induction. Brain death was induced in rats by inflation of a balloon catheter. Three groups (n=6) were compared: 1-hr BD, 4-hr BD, and sham-operated controls. RESULTS: An increased polymorphonuclear cell influx in ileum, as a measure of inflammation, was observed in 1- and 4-hr BD group compared with controls. Jejunum showed a significant increase at the 4-hr BD group compared with the control group. Intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and interleukin-6 were upregulated after 1- and 4-hr BD. Caspase-3 positive cells were found in jejunum and ileum after 4-hr BD on the top of the villi. Serum interleukin-6 was severely elevated in the 1- and 4-hr brain dead rats. CONCLUSION: These data show the early occurrence of intestinal inflammation and apoptosis after BD induction. These events may ultimately have a negative influence on the outcome of intestinal transplantation.