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Parametric and quantitative analysis of MR renographic curves for assessing the functional behaviour of the kidney.

The aim of this study was to refine the description of the renal function based on MR images and through transit-time curve analysis on a normal population and on a population with renal failure, using the quantitative model of the up-slope. Thirty patients referred for a kidney MR exam were divided in a first population with well-functioning kidneys and in a second population with renal failure from ischaemic kidney disease. The perfusion sequence consisted of an intravenous injection of Gd-DTPA and of a fast GRE sequence T1-TFE with 90 degrees magnetisation preparation (Intera 1.5 T MR System, Philips Medical System). To convert the signal intensity into 1/T1, which is proportional to the contrast media concentration, a flow-corrected calibration procedure was used. Following segmentation of regions of interest in the cortex and medulla of the kidney and in the abdominal aorta, outflow curves were obtained and filtered to remove the high frequency fluctuations. The model of the up-slope method was then applied. Significant reduction of the cortical perfusion (Qc = 0.057+/-0.030 ml/(s 100 g) to Qc = 0.030 +/- 0.017 ml/(s 100 g), P < 0.013) of the medullary perfusion (Qm = 0.023 +/- 0.018 ml/(s 100 g) to Qm = 0.011 +/- 0.006 ml/(s 100 g), P < 0.046) and of the accumulation of contrast media in the medulla (Qa = 0.005 +/- 0.003 ml/(s 100 g) to Qa = 0.0009 +/- 0.0008 ml/(s 100 g), P < 0.001) were found in presence of renal failure. High correlations were found between the creatinine level and the accumulation Qa in the medulla (r2 = 0.72, P < 0.05), and between the perfusion ratio Qc/Qm and the accumulation Qa in the medulla (r2 = 0.81, P < 0.05). No significant difference was found in times to peak between both populations despite a trend showing Ta the time to the end of the increasing contrast accumulation period in the medulla, arriving later for renal failure. Advances in MR signal calibration with the building of quantitative model such as the up-slope allow to assess kinetic and haemodynamic and functional parameters of the diseased kidney.

Contrast Media↗

Real-time transthoracic three-dimensional echocardiography provides additional information of left-sided AV valve morphology after AVSD repair.

AIMS: The purpose of this study was to assess the feasibility of real-time 3D echocardiography (RT-3DE) data acquisition in adult patients after atrioventricular septal defect (AVSD) repair and to evaluate whether RT-3DE has additional value over 2D echocardiography, regarding morphology and function of the left-sided AV valve (LAVV). METHODS: Twenty consecutive patients with surgically corrected partial or complete AVSD were enrolled in this study. The 3DE data sets were acquired with the Hewlett-Packard Sonos 7500 echo system (Philips Medical Systems, Andover, MA, USA). Images were reviewed off-line with assistance of TomTec Echoview 5.2 software (TomTec Inc., Munich, Germany) by experienced observers. En face reconstructions, from, respectively, the ventricular and atrial view, were made to evaluate the LAVV morphology and motion. RESULTS: 3DE reconstruction of the LAVV was feasible in 17 of 20 patients (85%). Mean time of 3DE acquisition was 9+/-6 min. The quality of the 3DE images was optimal in 35%, good in 30%, sufficient in 20% and insufficient in 15%. Identification of the LAVV structures was importantly better facilitated from a ventricular view. Accurate identification of LAVV morphology was possible in all 17 patients (85%). Relationship of the LAVV and the abnormal position of the LVOT was easier to evaluate from the 3DE reconstructions than from 2D echo. CONCLUSION: This study demonstrate that RT-3DE is feasible in daily practice and provides new insight into the dynamic morphology of the left-sided AV valve and LVOT anatomy after AVSD repair.

Adult↗

Civil liability in oral & maxillofacial surgery: &#x391; systematic review.

Maxillofacial surgery is a surgical specialty with anatomical, functional, and aesthetic requirements, which makes it a field at increased risk of medical negligence and subsequent legal claims. The review was conducted in accordance with the PRISMA guidelines and used international medical and legal databases. Studies that analyzed court decisions, insurance claims, or recorded compensation data related to maxillofacial surgery were included. The extracted data included, among others, the year and country of publication, the causes of action, and the amounts of financial compensation. Most lawsuits originate from countries with developed medical liability systems, primarily the United States and the United Kingdom, and there has been an increasing trend in publications over the last two decades. The most common causes of lawsuits involve nerve injuries, delayed or incorrect diagnoses, technical errors during surgery, and inadequate informed consent. The amounts of compensation vary widely, from lower five-digit amounts in milder cases to particularly high amounts in cases of permanent functional or aesthetic damage, placing a significant overall financial burden on health systems. Medical negligence in maxillofacial surgery constitutes an important forensic and socioeconomic issue. Understanding the causes of lawsuits and their financial consequences can help improve clinical practice, inform patients, and prevent legal disputes.

Humans↗

Incidence and factors associated with endodontic inter-appointment emergency in a dental teaching hospital in China.

OBJECTIVE: To assess the incidence of endodontic inter-appointment emergency (EIE) in a dental teaching hospital in China, and to correlate its occurrence with preoperative and treatment parameters. METHODS: Three thousand six hundred and ninety six cases were collected at root canal treatment appointments on demographics, presenting symptoms, treatment procedures and periradicular status. The operators consisted of faculty, undergraduate students and advanced trainees. Root canals were conventionally instrumented and then medicated. No systemic medication was prescribed. In cases EIE developed between appointments, an emergency visit was arranged and active treatment was carried out. The data of EIE cases were statistically analyzed using the chi-square test and a multiple logistic regression model. RESULTS: The overall incidence of EIE was 5%, which rate was 5.5% in females and 4.3% in males. Analyses of the potential factors revealed that patient age, tooth location, preoperative percussion pain and pulp status were the most important independent variables. CONCLUSION: EIE was significantly associated with some host factors (patient age, tooth location) and presenting factors (preoperative percussion pain, pulp status).

Adult↗

Cardiac index monitoring by pulse contour analysis and thermodilution after pediatric cardiac surgery.

OBJECTIVES: To validate a new device (PiCCO system; Pulsion Medical Systems, Munich, Germany), we compared cardiac index derived from transpulmonary thermodilution and from pulse contour analysis in pediatric patients after surgery for congenital heart disease. We performed a prospective clinical study in a pediatric cardiac intensive care unit of a university hospital. METHODS: Twenty-four patients who had had cardiac surgery for congenital heart disease (median age 4.2 years, range 1.4-15.2 years) were investigated in the first 24 hours after admission to the intensive care unit. A 3F thermodilution catheter was inserted in the femoral artery. Intracardiac shunts were excluded by echocardiography intraoperatively or postoperatively. Cardiac index derived from pulse contour analysis was documented in each patient 1, 4, 8, 12, 16, 20, and 24 hours after admission to the intensive care unit. Subsequently, a set of three measurements of thermodilution cardiac indices derived by injections into a central venous line was performed and calculated by the PiCCO system. RESULTS: The mean bias between cardiac indices derived by thermodilution and those derived by pulse contour analysis over all data points was 0.05 (SD 0.4) L x min x m(-2) (95% confidence interval 0.01-0.10). A strong correlation between thermodilution and contour analysis cardiac indices was calculated (Pearson correlation coefficient r = 0.93; coefficient of determination r2 = 0.86). CONCLUSIONS: Pulse contour analysis is a suitable method to monitor cardiac index over a wide range of indices after surgery for congenital heart disease in pediatric patients. Pulse contour analysis allows online monitoring of cardiac index. The PiCCO device can be recalibrated with the integrated transpulmonary thermodilution within a short time frame.

Adolescent↗

Correlations between cardiac output, stroke volume, central venous pressure, intra-abdominal pressure and total circulating blood volume in resuscitation of major burns.

The purpose of this study was to observe the interactions between cardiac index (CI), stroke volume index (SVI), central venous pressure (CVP), intra-abdominal pressure (IAP) and total circulating blood volume index (TBVI) during resuscitation of major burns. Sixteen patients with an average TBSA of 46% (26-67%) and an average abbreviated burn severity index of 8.9 (7-11) were included into an intra-individual comparative prospective study over an 18-month period. The COLD Z-021 system (Pulsion Medical Systems, Munich, Germany) was used to obtain CI, SVI and TBVI. Two hundred and thirty-four to 278 intra-individually comparative measurements were performed for the analyses during the first 4 days after the burn injury. Correlations were shown for the interactions between CI and TBVI (r = 0.550; rs = 0.518), SVI and TBVI (r = 0.606; rs = 0.626) and for CVP versus IAP (r = 0.487; rs = 0.474). Poor or no correlations were demonstrated for the comparisons CI versus CVP (r = 0.401; rs = 0.352), CVP-PEEP versus IAP (r = 0.255; rs = 0.272). TBVI versus IAP (r = -0.120; rs = -0.169), TBVI versus CVP (r = 0.025; rs = -0.036), TBVI versus CVP-PEEP (r = -0.046; rs = -0.101), CI versus CVP-PEEP (r = 0.088; rs = 0.092) as well as for IAP versus CI (r = 0.050; rs = 0.034). An additional analysis demonstrated no correlation between TBVI and MAP (r = -0.095; rs = -0.136). Our data provide evidence that the CVP is influenced more by external pressures (IAP) than by the actual intravascular volume status of the patient. Thus, the CVP is not a suitable tool to guide fluid resuscitation during burns with shock. The TBVI may be an ideal value to guide resuscitation because the augmentation of TBVI during fluid resuscitation correlated well with improved cardiac output and stroke volume. Future randomised studies are required to demonstrate whether TBVI guided resuscitation of burns has an impact on outcome.

Abdomen↗

New surgical technique for sphincter urinary control system using upper transverse scrotal incision.

PURPOSE: Traditional implantation of the AMS Sphincter 800 Urinary Control System (American Medical Systems, Minnetonka, Minnesota) requires 2 incisions. The cuff is placed via a perineal incision, and the pressure regulating balloon and pump are placed through a separate suprapubic incision. We describe a novel implantation of all the artificial urinary sphincter components using a single upper scrotal incision. The scrotal incision allows excellent access to the proximal bulbar urethra and retropubic and subdartos spaces, and leaves the bulbocavernosus muscle intact. MATERIALS AND METHODS: A total of 37 patients have undergone artificial urinary sphincter implantation using the new operative technique for revisions or reimplantations of a sphincter previously removed for infection/erosion (12) or as an initial procedure (25). In 9 of the 25 patients and 2 of the 12 dual implantation of a 3-piece penile prosthesis through the same incision was performed. RESULTS: All patients are using the devices. Of the patients 66% are completely dry with no pad use and the remainder use 1 pad for accident prevention. Operative time was reduced due to easier exposure of the urethra and a second incision for placement of the pressure regulating balloon was not necessary. Followup at 1 year shows no difference in complication rate with the single incision technique compared to the traditional method. CONCLUSIONS: Artificial urinary sphincter implantation through a single scrotal incision is easier and faster than the traditional 2-incision technique. Success in achieving continence is similar to traditional methods. Long-term followup is necessary to ensure that complications remain low.

Humans↗

Study to increase the frequency of autopsies performed for cases of infant deaths--proposed revision of the law on postmortem examination and corpse preservation and other related regulations.

By definition, sudden infant death syndrome (SIDS) requires diagnosis through exclusion by conducting an autopsy. To obtain a reliable diagnosis of this disease, an autopsy is essential. However, the frequency with which autopsies are conducted in Japan is not sufficient to meet the need associated with the diagnosis of SIDS. To improve this frequency, various public policies, such as nationwide implementation of the administrative autopsy system (medical examiner system), the application of the practice of autopsy approved by families, and legally required autopsies, are being considered; but none has been put into practice. On the other hand, attention has been called to the fact that the Law on postmortem examination and corpse preservation, which was instituted at the end of the Second World War, requires updating. In the current report, it is proposed that the following be added to Article 8, item 3 of this Law: "the Metropolitan or Prefectural Governor must insist that an autopsy be conducted on all cases of a sudden and unexpected death of an infant to investigate the cause of this death." At present, the annual incidence of SIDS in Japan is reported to be 500. To put the above-recommended legal requirement into practice, the estimated annual addition to the budget, if conducted as approved or an administrative autopsy, will be in the order of 150,000-500,000 dollar, which is within the prescribed limits for an appropriation.

Autopsy↗

Impact of lossy image compression on accuracy of caries detection in digital images taken with a storage phosphor system.

Image compression may reduce storage needs whether in the lossless (reversible) or lossy (irreversible) form. The aims of the study were to evaluate (1) storage needs, (2) subjective image quality, and (3) accuracy of caries detection in digital radiographs compressed to various levels by a lossy compression method. The material consisted of 116 extracted human premolars and molars. The teeth were mounted three in a line and radiographed by the Digora system (Sorodex Medical Systems, Helsinki, Finland). The images were exported in tagged image file format and compressed with the Lempel-Ziv-Welch reversible and the Joint Photographic Experts Group irreversible compression algorithm on four levels. The total of 580 images were assessed by five observers on a 5-rank confidence scale for caries diagnosis. The observers subjectively judged image quality on an 11-point rank scale. With the reversible compression, images could be compressed to less than 50% of the original storage needs whereas the four irreversible compression factors compressed to 20%, 8%, 5%, and 3%, respectively. For occlusal surfaces, when receiver operating characteristic curve areas were increasingly smaller and the compression rate was higher. The difference between the original and the most compressed images was 14% (p = 0.1). The median quality score was above middle on the 11-point rank scale for all except the most compressed images (median score = 1). In conclusion, for caries diagnosis, compression ratio rates of 1:12 can be justified before accuracy and image quality is significantly affected.

Dental Caries↗

The perceptibility curve test applied to direct digital dental radiography.

OBJECTIVE: To compare the effect of an additional scintillator layer on the psychophysical properties of a CCD detector for digital dental radiography. METHODS: Radiographs of a test object containing ten holes of increasing depth were obtained throughout the exposure range of two CCD detectors at 70 and 90 kVp. One was the original detector for the Sens-A-Ray system (Regam Medical Systems, Sundsvall, Sweden) and the other the same detector covered by a scintillator layer. Ten viewers evaluated the radiographs for the number of perceptible holes. From these data and the dose response functions for the two detectors, the minimum perceptible exposure difference was found. The reciprocal values of this parameter were plotted against the logarithm of exposure to create Perceptibility Curves (PCs). RESULTS: The four PCs had essentially the same shape and height. There was a shift to lower exposures in the PCs for the detector covered by a scintillator. CONCLUSIONS: The two detectors have essentially the same psychophysical properties. Since the detector covered by a scintillator layer is more sensitive, it should be preferred for clinical practice since the dose to the patient is reduced.

Absorptiometry, Photon↗

[Radiation exposure in single slice and multi-slice spiral CT (a phantom study)].

PURPOSE: The purpose of study was to compare patient dose applying singleslice- and multislice-spiral CT. METHODS: The examinations were performed with a singleslice-spiral CT (Highspeed Advantage; GE Medical Systems; Milwaukee, USA) and with a multislice CT systems (LightSpeed QX/i GE Medical Systems; Milwaukee, USA). For the determination of the radiation exposure (absorbed dose) a selection of most executed protocols (thorax-helical, abdomen-helical, petrous bone-axial, head-axial) were simulated using an Alderson Rando Phantom. The dose was determined by means of lithiumfluorid-thermoluminiscence dosimeters (TLD-GR 200). RESULTS: For thorax and abdomen protocols higher energy dose values could be found using a multislice CT. On the average the energy dose values were increased by 2.6 on an average in relation to single slice spiral CT. The energy dose values of the multisclice CT using head protocols could be reduced by 30% in relation to single slice spiral CT due to suitable parameter selections. The energy dose applying a petrous bone protocol resulted in an average increase by a factor 1.5 using a multislice CT. CONCLUSION: Using the new multislice CT technique protocol strategies must be optimized regarding the patient doses. Users can operate critically in the sense of the radiation protection only if they are aware of the occurring dose amounts to the patient.

Equipment Design↗

MR elastography of the prostate: initial in-vivo application.

PURPOSE: To analyze the initial assessment of the technical feasibility of in-vivo MR elastography (MRE) of the prostate gland in healthy volunteers. MATERIALS AND METHODS: Dynamic sinusoidal MR elastography was performed in 7 healthy volunteers in prone position. The mechanical wave was induced via an external oscillator attached to the pubic bone. A 1.5 Tesla MR system (Philips Medical Systems, Netherland) was used with 4 combined surface coils for signal reception. MRE data acquisition was performed with a motion-sensitive spin-echo MR sequence that was phase-locked to the mechanical oscillation. Subsequently, these images were used to reconstruct the local distribution of elasticity inside the prostate gland. The applied reconstruction algorithm was tested by means of phantom measurements. RESULTS: Sufficient penetration of the mechanical wave into the prostate gland was achieved in all volunteers, allowing the acquisition of utilizable image data sets. The reconstructed distribution of elasticity (shear-modulus) inside the healthy prostate gland correlated with the zonal anatomy of the gland. The elasticity of the central portion (2.2 +/- 0.3 kPa) appeared to be lower than the peripheral prostatic portion (3.3 +/- 0.5 kPa). CONCLUSION: In-vivo MRE of the prostate gland is technically feasible. The proposed experimental set-up allows the efficient insertion of the mechanical wave into the prostate gland and provides a successful MR data acquisition.

Adult↗

Needle-based ablation of renal parenchyma using microwave, cryoablation, impedance- and temperature-based monopolar and bipolar radiofrequency, and liquid and gel chemoablation: laboratory studies and review of the literature.

BACKGROUND AND PURPOSE: Small renal tumors are often serendipitously detected during the screening of patients for renal or other disease entities. Rather than perform a radical or partial nephrectomy for these diminutive lesions, several centers have begun to explore a variety of ablative energy sources that could be applied directly via a percutaneously placed needle-like probe. To evaluate the utility of such treatment for small renal tumors/masses, we compared the feasibility, regularity (consistency in size and shape), and reproducibility of necrosis produced in normal porcine kidneys by different modes of tissue ablation: microwaves, cold impedance-based and temperature-based radiofrequency (RF) energy (monopolar and bipolar), and chemical. Chemoablation was accomplished using ethanol gel, hypertonic saline gel, and acetic acid gel either alone or with simultaneous application of monopolar or bipolar RF energy. MATERIALS AND METHODS: A total of 107 renal lesions were created laparoscopically in 33 domestic pigs. Microwave thermoablation (N=12) was done using a Targis T3 (Urologix) 10F antenna. Cryoablation (N=16) was done using a single 1.5-mm probe or three 17F microprobes (17F SeedNet system; Galil Medical) (N=10 single probe and N=6 three probes); a double freeze cycle with a passive thaw was employed under ultrasound guidance. Dry RF lesions were created using custom-made 18-gauge single-needle monopolar probe with two or three exposed metal tips (GelTx) (N=12) or a single-needle bipolar probe (N=6) at 50 W of 510 kHz RF energy for 5 minutes. In addition, a multitine RF probe (RITA Medical Systems) was used in one set of studies (N=6). Both impedance- and temperature-based RF were evaluated. Chemoablation was performed with 95% ethanol (4 mL), 24% hypertonic saline (4 mL), and 50% acetic acid (4 mL) as single injections. In addition, chemoablation was tested with monopolar and bipolar RF (wet RF). Tissues were harvested 1 week after ablation for light microscopy. RESULTS: In 11 of the 15 ablation techniques, there was complete necrosis in all lesions; however, three ethanol gel lesions had skip areas, three hypertonic saline gel lesions showed no necrosis or injury, and one monopolar RF and one bipolar RF lesion showed skip areas. In contrast to impedance-based RF, heat-based RF (RITA) caused complete necrosis without skip areas. All cryolesions resulted in complete tissue necrosis, and cryotherapy was the only modality for which lesion size could be effectively monitored using ultrasound imaging. CONCLUSIONS: Cryoablation and thermotherapy produce well-delineated, completely necrotic renal lesions. The single-probe monopolar and bipolar RF produce limited areas of tissue necrosis; however, both are enhanced by using hypertonic saline, acetic acid, or ethanol gel. Hypertonic saline gel with RF consistently provided the largest lesions. Ethanol and hypertonic saline gels tested alone failed to produce consistent cellular necrosis at 1 week. In contrast, RITA using the Starburst XL probe produced consistent necrosis, while impedance-based RF left skip areas of viable tissue. Renal cryotherapy under ultrasound surveillance produced hypoechoic lesions, which could be reasonably monitored, while all other modalities yielded hyperechoic lesions the margins of which could not be properly monitored with ultrasound imaging.

Acetic Acid↗

Endocytoscopy: novel endoscopic imaging technology for in-situ observation of bladder cancer cells.

BACKGROUND AND PURPOSE: Recent advances in endoscopy have enabled microscopic imaging of live bladdercancer cells in situ. The newly developed Endocystoscopy system (Olympus Medical Systems Co., Tokyo, Japan) is a flexible digital endoscope that has more than a 450-fold magnifying power on a video monitor. PATIENTS AND METHODS: This supermagnifying endoscope was used to evaluate bladder carcinoma in five patients through the working channel of a rigid cystoscope. RESULTS: The cell structure and nuclear morphology were imaged adequately compared with conventional hematoxylin and eosin staining of a biopsy specimen. The tumors were graded correctly in four of five cases. CONCLUSION: This novel technology appears to be useful for histologic diagnosis during endoscopic examinations, potentially allowing us to avoid a conventional biopsy.

Aged↗

Magnetic resonance imaging-guided neurosurgery in the magnetic fringe fields: the next step in neuronavigation.

OBJECTIVE: We describe the development of an alternative approach to intraoperative magnetic resonance imaging (iMR)-guided neurosurgery and report our initial experience with 22 craniotomies and 16 brain biopsies. The advantages and disadvantages of each approach are examined. METHODS: An iMR suite houses a 0.2-T open configuration system (Siemens Medical Systems, Erlangen, Germany) and is equipped with anesthetic gases and a magnetic resonance imaging (MRI)-compatible anesthesia machine and monitor. Standard operating instruments and equipment were tested for safety and compatibility in the magnetic fringe fields surrounding the open MRI system. We then performed brain biopsies and craniotomies in the iMR suite. RESULTS: Standard operating equipment functioned properly in the 0.5- to 10-mT zone and was not affected by the magnet's attractive force. Twenty-two craniotomies and 16 brain biopsies were performed in the interventional suite, using serial intraoperative MRI guidance, without injury to patients or operating room staff. CONCLUSION: Full neurosurgical procedures may be performed in the weak fringe fields surrounding an MRI system, using standard operating room equipment. This approach to iMR-guided neurosurgery offers a significant cost advantage over retrofitting an entire operative suite with "MRI-compatible" surgical equipment. The surgeon's familiarity with standard equipment and the reliability of the equipment are additional advantages. Neurosurgery in the fringe fields allows the neurosurgeon to utilize serial MRI with a minimum of inconvenience, disruption, and change to the standard neurosurgical procedure. Serial intraoperative imaging to visualize the changes in the brain that are associated with neurosurgical intervention seems to enhance the ability to safely and effectively accomplish neurosurgical goals.

Adolescent↗

Overexpression of HER-2 in thick melanoma.

In this study we evaluated the overexpression status of HER-2 and its prognostic significance on survival in patients with thick cutaneous malignant melanoma. The immuno-alkaline phosphatase antigen detection technique was applied to archival diagnostic material from 51 patients with primary lesions measuring >or= 10 mm in Breslow thickness. Eleven additional patients with primary lesions measuring <or= 1 mm were also studied. HER-2 overexpression was evaluated using conventional light microscopy and an automated cellular imaging system (Chromavision Medical System). Fifteen (29.4%) out of 51 patients with thick lesions showed HER-2 overexpression. In contrast, no overexpression was seen in any of the thin lesions. Overexpression of HER-2 in this group of patients was of no prognostic significance for freedom from recurrence or survival when studied using univariate and multivariate analyses. Whilst the incidence of HER-2 overexpression in patients with thick cutaneous primary melanoma is similar to that reported in breast cancer, it was of no prognostic significance for survival in this study. However, further evaluation in larger numbers of patients with the full spectrum of Breslow thickness is clearly indicated.

Alkaline Phosphatase↗

Transcardiopulmonary thermal dye versus single thermodilution methods for assessment of intrathoracic blood volume and extravascular lung water in major burn resuscitation.

The purpose of this study was to compare the approximated values for intrathoracic blood volume (ITBV) and extravascular lung water (EVLW) obtained from a single indicator dilution to the exact data measured by double-indicator dilution. Eighteen patients with an average TBSA of 46.3% (range, 26 to 67%) and an average abbreviated burn severity index of 8.7 (range, 7 to 11) were included into a intraindividual comparative prospective study over a 20-month period. The COLD Z-021 system (Pulsion Medical Systems, Munich, Germany) was used to obtain both the exact measurements, as well as the estimated values for ITBV and EVLW. Two hundred ninety intraindividually comparative measurements were performed during the first 4 days after the burn injury. A good correlation between both techniques was shown for ITBVI (0.77; P <.01) for the overall measurements. However, the overall bias demonstrated a standard deviation higher than the mean value (-87.4 +/- 136 ml/m2), and precision for the estimated values for ITBVI was poor (-491 to 783 ml/m2). Additional analyses demonstrated a poor but significant correlation for low states of ITBV (r =.37; P <.01), but no significant correlations were found between the techniques for normal and high ITBV states. Thus, the approximated ITBV obtained from single thermodilution should not be used to guide volume therapy in major burn resuscitation. Furthermore, the EVLW is neither suitable for diagnostic use nor for therapeutic decisions because it is calculated on the basis of the poorly estimated values for ITBV in single thermodilution. Transcardiopulmonary single thermodilution is not suitable to assess intrathoracic blood volume and extravascular lung water in burn shock. However, the method is suitable to assess cardiac output and its derived parameters in burn resuscitation as shown in previous studies. It still must be proven whether the exactly measured ITBV obtained from transcardiopulmonary double-indicator dilution is superior to the commonly used parameters to guide major burn resuscitation.

Adult↗

A biomechanical comparison of sacral pedicle screw salvage techniques.

STUDY DESIGN: Biomechanical cadaver study. OBJECTIVES: The purpose of our study was to compare the pullout strength of standard, expandable, and cement-augmented pedicle screws. SUMMARY OF BACKGROUND DATA: Salvage procedures are needed to restore the stability of lumbosacral arthrodesis when pedicle screw fixation in the sacrum fails. METHODS: Thirteen pairs of sacral (S1) pedicles were implanted initially with 7-mm tapped monoaxial stainless steel pedicle screws (Moss Miami, Depuy Spine, Raynham, MA) inserted under fluoroscopy with bicortical purchase. The screws were distracted axially at a rate of 6 mm/min to measure pullout strength. One pedicle of each pair was assigned randomly to be revised with an expandable pedicle screw (omega-21 Spinal Fixation System, EBI Medical Systems, Parsippany, NJ); the contralateral pedicle was revised with a screw augmented with polymethylmethacrylate (Simplex P, Howmedica, Mahwah, NJ). The screws then were retested as before to measure pullout strength. RESULTS: Expandable screws (391 +/- 28 N) and polymethylmethacrylate-augmented screws (599 +/- 28 N) exhibited significantly greater pullout strength than their respective initial standard pedicle screws (145 +/- 28 N and 156 +/- 28 N). CONCLUSIONS: Our results suggest that expandable pedicle screws may provide sufficient fixation, but these results need clinical verification.

Aged↗