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At least 937 records · Page 52Linked to original sources
PubMed2006

Accuracy of the 7-8-9 Rule for endotracheal tube placement in the neonate.

OBJECTIVE: To determine accuracy of the 7-8-9 Rule in a cohort of neonates. STUDY DESIGN: This study was cross-sectional in design. Seventy-five consecutive neonates who required oral intubation from June 2004 to November 2004 for cardiopulmonary failure, respiratory distress, or surfactant administration were the subjects of this study. The initial endotracheal tube (ETT) depth of insertion was determined using either an estimated birth weight or actual weight in the 7-8-9 Rule calculation followed by auscultation and subsequent adjustment if necessary. Midtracheal position was identified as the point halfway between the inferior clavicle and carina on a chest radiograph. The initial depth was compared to the midtracheal depth to determine clinical accuracy of the 7-8-9 Rule. The depth predicted by the 7-8-9 Rule was also calculated using only actual weights. This predicted depth was compared to the midtracheal depth to determine true accuracy of the 7-8-9 Rule. Accuracy was determined using mean paired differences with 95% confidence intervals (CI) between initial or predicted depth and ideal, midtracheal ETT depth. Linear regression was used to adjust for confounding variables. RESULTS: Mean (range) gestational age was 32 weeks (23 to 44 weeks) and weight was 2001 g (490 to 4400 g). Eighteen (24%) infants weighed 1000 g or less, 20 (27%) weighed between 1001 and 2000 g, 21 (28%) weighed between 2001 and 3000 g, 15 (20%) weighed between 3001 and 4000 g, and one (1%) weighed more than 4000 g. Thirteen of the 18 extremely low birth weight infants weighed <750 g. The initial depth of insertion was 0.004 cm above midtracheal position (95% CI -0.13 to 0.14, P = 0.96). After controlling for head position, the initial depth did not significantly differ from the midtracheal position among weight groups. Predicted depth using the 7-8-9 Rule placed the ETT 0.12 cm above midtracheal position (95% CI -0.30 to 0.06, P = 0.20). However, after controlling for head position, the 7-8-9 Rule positioned the ETT significantly below midtracheal position in infants weighing <750 g (mean 0.62 cm; 95% CI 0.30 to 0.93, P=0.002). CONCLUSIONS: The 7-8-9 Rule appears to be an accurate clinical method for endotracheal tube placement in neonates weighing more than 750 g. When the 7-8-9 Rule is applied to infants weighing <750 g, caution is warranted. The current rule may lead to an overestimated depth of insertion and potentially result in clinically significant consequences.

Body Weight↗
PubMed1995

Accuracy of speech intelligibility index predictions for noise-masked young listeners with normal hearing and for elderly listeners with hearing impairment.

This study examined whether the accuracy of Speech Intelligibility Index (SII) predictions is affected by subject age when between-groups auditory sensitivity differences are controlled. SII predictive accuracy was assessed for elderly listeners with hearing impairment (EHI) and for young noise-masked listeners with normal hearing (NMN). SII predictive accuracy was poorer for the EHI subjects than for the NMN subjects across a range of test conditions and stimuli. Speech test redundancy, speech presentation level, signal-to-babble ratio, and babble level also affected SII predictive accuracy. The results suggest that the speech recognition difficulties experienced in noise by elderly listeners do not result solely from reduced auditory sensitivity.

Adult↗
PubMed1996

Time-interval measurement of stuttering: establishing and modifying judgment accuracy.

The purpose of this study was to determine whether accuracy training for interval judgments of stuttering might generalize to increased accuracy and/or interjudge agreement for intervals other than those used during training. Ten upper-division speech-language pathology students judged 5-s audiovisually recorded speech intervals as stuttered or nonstuttered in a series of group and single-subject experiments. Judgment accuracy was determined with respect to judgments provided previously by 10 recognized authorities on stuttering and its treatment. Training occurred within single-subject experiments that used multiple baselines across speakers and repeated generalization probes to assess training effects. Results showed that judgment accuracy tended to increase after training for speakers used during the training process as well as for unfamiliar speakers. Results also replicated previous findings of slight increases in interjudge and intrajudge agreement after interval-judgment training. The implications of these results for developing a valid and reliable stuttering measurement system are discussed.

Female↗
PubMed1998

Accuracy of irreversible hydrocolloids (alginates) for fixed prosthodontics. A comparison between irreversible hydrocolloid, reversible hydrocolloid, and addition silicone for use in the syringe-tray technique.

One reversible, seven irreversible hydrocolloids and two addition silicones were examined. The aim was to study their ability to reproduce six differently shaped abutments of a full arch stainless steel master model correctly, by measuring: 1) the accuracy of irreversible hydrocolloid impressions with different storage periods of 15 min, 2 h, 24 h and 95 h, reversible hydrocolloid stored 15 min and 2 h, and Type III addition silicones stored 24 h when the syringe-tray technique was used; and 2) whether mixing technique or tray design had any influence of the accuracy of irreversible hydrocolloid impressions. All the tested impression materials had difficulties in producing full arch casts, where the six abutments were correctly reproduced, because 58% of the heights and 45% of the diameters of the occlusal surfaces were shorter than the corresponding distances of the master model. Storage time, mixing technique and tray design were of significant importance for the irreversible hydrocolloids. Concerning the accuracy at the gingival margin, a shorter storage time resulted in improved accuracy, and mechanical mixing without a vacuum and a tray designed similar to a perforated stock tray gave most accurate impressions.

Alginates↗
PubMed2001

The accuracy of patient records in Swedish nursing homes: congruence of record content and nurses' and patients' descriptions.

The accuracy of patient records in Swedish nursing homes: congruence of record content and nurses' and patients' descriptions. Data from patient records will increasingly be used for care planning, quality assessment, research, health planning and allocation of resources. Knowledge about the accuracy of such secondary data, however, is limited and only a few studies have been conducted on the accuracy of nursing recording. The aim of this study was to analyse the concordance between the nursing documentation in nursing homes and descriptions of some specific problems of nurses and patients. Comparisons were made between wards where nurses had received training in structured recording based on the nursing process (study group) and wards where no intervention had taken place (reference group). Data were collected from the patient records of randomly selected nursing home residents (n=85). The methods used were audits of patient records and structured interviews with residents and nurses. The study revealed considerable deficiencies in the accuracy of the patient records when the records were compared with the reports from nurses and residents. The overall agreement between the interview data from nurses and from the patient records was low. Concordance was better in the study group as compared with the reference group in which the recorded data were structured only following chronological order. The study unequivocally demonstrates that there are major limitations in using records as a data source for the evaluation, planning and development of care.

Aged↗
PubMed2004

Accuracy of endoscopic ultrasound for restaging rectal cancer following neoadjuvant chemoradiation therapy.

OBJECTIVES: Endoscopic ultrasound (EUS) provides important information in the initial staging of patients with rectal cancer. Preoperative combined modality chemotherapy and radiation (neoadjuvant therapy) for patients with locally advanced rectal cancer may reduce local recurrence and improve survival. The accuracy of EUS restaging of rectal cancer after chemoradiation has not been extensively studied and its usefulness is unclear. The aim of this study was to verify the accuracy of EUS in staging rectal cancer after neoadjuvant chemoradiation in a large cohort of patients. METHODS: EUS staging was performed before and after concurrent 5-fluorouracil and hyperfractionated radiotherapy in 82 patients with recently diagnosed locally advanced rectal cancer. All patients underwent subsequent surgical resection and complete pathologic staging. RESULTS: After chemoradiation, 16 patients (20%) had no residual disease at pathologic staging. (T0N0). However, EUS correctly predicted complete response to chemoradiation in only 10 of 16 patients (63%). Overall accuracy of EUS post chemoradiation for pathologic T-stage was only 48%. Fourteen percent were understaged and 38% overstaged. EUS accuracy for N-stage was 77%. The T-category was correctly staged before surgery in 23 of the 56 responders (41%) and in 16 of 24 nonresponders (67%). EUS was unable to accurately distinguish postradiation changes from residual tumor. CONCLUSION: EUS staging of rectal cancer after chemoradiation is inaccurate, especially in the group of patients with visual and EUS evidence of response. Its routine use for staging purposes after neoadjuvant chemoradiation for rectal cancer should be discouraged.

Adult↗
PubMed2000

The accuracy of pulse oximetry in the emergency department.

The objective of this retrospective study was to identify factors affecting the accuracy of pulse oximetry in the ED. Over a 3-year period, 664 consecutive emergency department (ED) patients had simultaneous arterial blood gas (ABG) and pulse oximeter readings taken. Pulse oximeter saturations (SpO2) were compared with ABG CO-oximeter saturations (SaO2) for accuracy. Multiple variables including age, sex, hemoglobin, bicarbonate, pH, and carboxyhemoglobin (COHb) were analyzed to see if they affected SpO2 accuracy. ROC curves were used to determine the best pulse oximeter threshold for detecting hypoxia. Using multivariate analysis, COHb was the only statistically significant factor affecting the accuracy of pulse oximetry. In patients with COHb <2%, SpO2 overestimated SaO2 by more than 4% in 8.4% of cases. In patients with COHb > or = 2%, SpO2 overestimated SaO2 by more than 4% in 35% of cases. The best pulse oximetry threshold for detecting hypoxia is 92%. At this threshold, if COHb is <2%, pulse oximetry has a sensitivity of 0.92 and specificity of 0.90. If COHb is > or =2%, sensitivity is 0.74 and specificity is 0.84. For patients likely to have a COHb < 2, pulse oximetry is an effective screening tool for detecting hypoxia. However, more caution must be exercised when using pulse oximetry in patients likely to have a COHb > or = 2%.

Blood Gas Analysis↗
PubMed2000

Accuracy of ED sonography in the diagnosis of acute appendicitis.

The objective was to compare the accuracy of abdominal sonography performed by emergency physicians in the diagnosis of acute appendicitis with that of the surgeons' clinical impression. Three hundred-seventeen patients with right lower abdominal pain admitted to the Department of Emergency Medicine at National Taiwan University Hospital in Taipei, Taiwan were prospectively included in this study. Patients were divided into two groups according to the time of day they visited the emergency department. Those patients visiting the emergency department during the day were included in group I and those during the night were in group II. Group I was diagnosed by sonography. Group II was diagnosed by surgeons' clinical impression without sonographic examination. The definitive diagnosis of acute appendicitis was confirmed by the pathological reports. In the diagnosis of acute appendicitis, group I had a sensitivity of 96.4%, a specificity of 67.6%, a positive predictive value of 89.8%, a negative predictive value of 86.2%, and an accuracy of 89.1%, and group II had a sensitivity of 86.2%, a specificity of 37.0%, a positive predictive value of 74.6%, a negative predictive value of 55.6%, and an accuracy of 70.6%. The overall accuracy of sonography performed by emergency physicians in the diagnosis of acute appendicitis was superior to that of the surgeons' clinical impression.

Acute Disease↗
PubMed2003

Accuracy and reliability of arthroscopic estimates of cartilage lesion size in a plastic knee simulation model.

PURPOSE: The goal of the study was to determine the accuracy and reliability of arthroscopic percent area estimates in a plastic knee simulation model. A second goal was to determine the effect of lesion location within the knee and lesion size on accuracy and reliability. TYPE OF STUDY: Cross-sectional study of arthroscopic estimates of cartilage lesion size. METHODS: Three experienced arthroscopists performed 3 sets arthroscopic percent area estimates in 5 different plastic knees. Each knee had lesions drawn on 5 surfaces (patellar, medial and lateral femoral condyle, medial and lateral tibial plateaus). Accuracy and reliability were studied using Bland and Altman limits of agreement (LOA) and intraclass correlation coefficients. RESULTS: There was a strong tendency to overestimate lesion size by over 100% on the femoral and patellar surfaces. Intraobserver and interobserver reliabilities were generally poor. The range for the 95% LOA (+/- 1.96 standard deviation [SD] of the difference scores) between repeated measurements was almost 6 times the size of the lesion itself. Reliability of estimates was poorest for the largest lesions and worse at femoral, lateral tibial, and patellar sites. CONCLUSIONS: Assessments of arthroscopic measurements using LOA found that accuracy and reliability were generally poor, although results were better at the medial tibial plateau and for smaller lesions. In spite of these problems, arthroscopy remains a promising measurement tool because it permits physical assessment of cartilage integrity. This study sets the foundations for improvement in techniques of arthroscopic measurement of cartilage lesion size.

Anthropometry↗
PubMed2001

Accuracy of predictions of survival at admission to the intensive care unit.

PURPOSE: The purpose of this study was to compare the accuracy of outcome predictions made on the day of intensive care unit (ICU) admission by critical care physicians, critical care fellows, and primary team physicians. PATIENTS AND METHODS: Fifty-nine consecutive patients admitted to a Medical-Surgical ICU were included in the study. Two ICU attending physicians and two critical care fellows, not involved in medical management, evaluated each new ICU patient at admission and after 48 to 72 hours. Altogether six ICU attendings and six fellows were involved in the study. Each investigator separately assigned probability to each patient of being discharged alive from the ICU and the hospital. On the day of admission the primary service was also asked to estimate the likelihood of successful outcome. All values are expressed in percentiles. Statistical analysis was performed by a logistic regression procedure with a binary outcome. Data are presented as mean +/- SD. RESULTS: Fifty-nine patients were surveyed. Twenty-six (44%) patients died in the ICU, 3 (5%) died in the hospital wards, and 30 (51%) were discharged alive from the hospital. ICU attendings most reliably and accurately estimated patient outcome on admission compared with critical care fellows and primary team physicians. ICU attendings were more consistent than ICU fellows at predicting outcome at 48 and 72 hours. Clinical predictions were better for patients at the extremes of disease severity, and the accuracy of predictions in these patients was highest. Accuracy was diminished in patients with moderate compromise of clinical status. CONCLUSION: ICU attendings predicted most accurately and consistently the final outcome of patients, and ICU fellows estimated outcome more reliably than the primary service. For the most part, the primary service tended to overestimate the probability of favorable outcome of patients for whom ICU admission had been requested. Additionally, clinical accuracy of survival or mortality was best for those patients at the extremes of clinical compromise: this point seems to confirm the validity of using clinical judgement as a guide to restricting ICU resources for those severely compromised or mildly compromised.This study also indicates that predictions of outcome in critically ill patients made within days of admission are statistically valid but not sufficiently reliable to justify irrevocable clinical decisions at present.

Cancer Care Facilities↗
PubMedDate not supplied

Delivery rate accuracy of portable, bolus-capable infusion pumps used for patient-controlled continuous regional analgesia.

BACKGROUND AND OBJECTIVES: Portable patient-controlled pumps used for perineural local anesthetic infusion appear to be gaining acceptance and are used for an increasing number of medically unsupervised ambulatory patients. The infusion rate accuracy and reliability of these pumps, which allow patient-controlled boluses of potentially toxic medication, has not been independently investigated. We performed this laboratory study to define the flow-rate accuracy, reliability, and profiles of various portable bolus-capable infusion pumps and varied several factors that may influence pump performance. METHODS: Using a computer/scale combination, 4 electronic pumps were tested with 1 and 2 sets of batteries over 100 hours. One elastomeric pump was tested with its flow-regulator at room temperature (20 degrees C to 24 degrees C), skin temperature (32 degrees C), and increased temperature (36 degrees C). The elastomeric pump was also tested by varying the height of the pump relative to the distal end of the catheter. RESULTS: Infusion rate accuracy differed significantly among the pumps, exhibiting flow rates within +/-15% of their expected rate for 29% to 100% of their infusion duration. Changing the batteries after 50 hours affected the profile of 1 of the 4 electronic pumps. For the elastomeric pump, an increase in temperature significantly increased the infusion rate. An increase or decrease in pump-to-scale height significantly increased or decreased the infusion rate, respectively. CONCLUSIONS: These results suggest that factors such as flow-rate accuracy and consistency, infusion profile, and temperature sensitivity should be taken into consideration when choosing a portable infusion pump for local anesthetic administration.

Analgesia, Patient-Controlled↗
PubMed2002

Pre-operative prediction of invasive vs intraductal breast cancer type: multivariate analysis of the accuracy of clinical and imaging findings.

Two consecutive series of 107 invasive carcinomas and 108 carcinomas in situ of the breast were considered retrospectively. The main symptomatic, clinical and cytological features were retrieved from clinical records, whereas the features at mammography and/or ultrasonography were reclassified at a blinded review by an expert radiologist. The power of predicting invasion on the basis of these features was then evaluated. The accuracy of such a prediction was compared to that of a mathematical model using the same diagnostic features by multivariate logistic regression analysis. Neither approach reached a satisfactory accuracy, but the radiologist's judgment (sensitivity 97.1%, specificity 81.9%, positive predictive value 98.4%, negative predictive value 71.6%, overall accuracy 95.8%) was slightly superior to the mathematical model (sensitivity 93.2%, specificity 87.9% positive predictive value 98.8%, negative predictive value 53.7%, overall accuracy 92.8%). Although some presentations are significantly associated with invasive or in situ status, diagnostic features alone are not sufficiently accurate to bypass histological confirmation, although they might give useful clinical indications.

Journal Article↗
PubMed1979

[Studies on the diagnostic accuracy of lymphography (author's transl)].

Contradictory reports in the literature on the reliability of lymphography stimulated the authors to test the diagnostic accuracy, employing methods which are approximately analogous to practice, using carcinoma of the cervix as the model on which the study was carried out. Using 21 observers it was found that there was no correlation between their experience and on-target accuracy of the diagnosis. Good observers obtained an accuracy of 85% with good proportions between sensitivity in the recognition of detail, specificity and readiness to arrive at a decision on the basis of discriminatory ability. With the help of the concept of the ROC curves, the position taken up by the observers in respect of diagnostic decisions, and a complex manner of assessing the various characteristic factors determining diagnostic accuracy, are demonstrated. This form of test, which permits manipulation of different variants of diagnosis, is recommended, among other things, for performance control at the end of training and continuing education courses in other fields of x-ray diagnosis as well.

Female↗
PubMed2003

[Accuracy of renal volume assessment in children by three-dimensional sonography].

PURPOSE: Prospective evaluation of the accuracy of three-dimensional ultrasound (3DUS) to assess the renal parenchymal volume. MATERIALS AND METHODS: CT, MRI, 2DUS and 3DUS were used to measure the renal volume in 40 patients (range: neonate to 17 years; mean age: 8.95 years). The 3DUS was determined with a Voluson 730 (Kretztechnik, GE) or an external 3D-system (EchoTech, GE) using electromagnetic positioning sensors attached to conventional 2DUS-equipment. The 2DUS volume was calculated with the ellipsoid equation and the 3DUS volume computed with the system integrated software. For CT and MRI, planimetric analysis was used to determine the renal parenchymal volume, whereby the dilated collecting system of a hydronephrosis was subtracted to obtain the real renal parenchymal volume. The results of 2DUS and 3DUS were compared to the results of CT and MRI, and inter- and intraobserver variabilities were calculated. RESULTS: In 74 of 77 kidneys, the 3DUS study was of diagnostic quality. The accuracy of the 3DUS volumes compared well to the CT and MRI volumes with a mean difference of -1.8 +/- 4.6 % versus a mean difference of -2.4 +/- 15.4 % for 2DUS. In normal kidneys, the accuracy was -2.6 +/- 4.4 % for 3DUS and -3.8 +/- 14.7 % for 2DUS. In hydronephrosis, the accuracy was +4.0 +/- 5.9 % and +9.6 +/- 21.3 %, respectively, indicating that 3DUS is more accurate than 2DUS, particularly in kidneys with a dilated collecting system. Inter- and intraobserver variabilities were +/- 7.3 % and +/- 5.3 %. CONCLUSION: For assessing the renal parenchymal volume in children, 3DUS is feasible and comparable to CT and MRI.

Adolescent↗
PubMed2003

Effects of body mass index on the accuracy of an electronic pedometer.

Electronic pedometers are accurate for assessing steps taken while walking in normal weight adults but the accuracy of these devices has not been tested in overweight and obese men and women. The primary purpose of this study was to assess the accuracy of an electronic pedometer for measuring steps taken at various walking speeds in groups of adults with variations in body mass index (BMI). The secondary purpose was to determine if the manufacturer recommended position is the best placement position for overweight and obese adults. Participants were categorized into one of three BMI categories identified by the World Health Organization: normal (N = 25; < 25 kg x m(-2)), overweight (N = 24; 25 - 29.9 kg x m(-2)), or obese (N = 17; > or = 30 kg x m(-2)). Participants walked on a treadmill for 3 min at 54, 67, 80, 94, and 107 m x min(-1) for a total of 15 min. During the treadmill walking, three electronic pedometers tallied steps taken. The pedometers were placed at the waist level, one on the anterior mid-line of the thigh (front; manufacturer recommended placement), one on the mid-axillary line (side), and one on the posterior mid-line of the thigh (back). Concurrently, a researcher counted steps using a hand-tally counter. Category of BMI did not affect the accuracy of the pedometer at any walking speed (54 m x min(-1), p = 0.991; 67 m x min(-1), p = 0.556; 80 m x min(-1), p = 0.591; 94 m x min(-1), p = 0.426; 107 m x min(-1), p = 0.869). At 54 m x min(-1), the front, side, and back pedometers significantly underestimated hand-tally counted steps by 20 % (p < 0.001), 33 % (p < 0.001), and 26 % (p < 0.001), respectively. At 67 m x min(-1) the front, side, and back pedometers significantly underestimated hand-tally counted steps by 7 % (p = 0.027), 13 % (p < 0.001), 11 % (p = 0.002), respectively. The steps recorded by the electronic pedometers placed at the front, side and back of the waist were not significantly different than steps counted by the hand-tally counter at speeds of 80 m x min(-1) and higher for all subjects combined. An electronic pedometer accurately quantified steps walked at speeds of 80 m x min(-1) or faster in persons with a normal BMI and those classified as overweight or obese. The placement of the pedometer on the front, side or back of the waistband did not affect accuracy of the pedometer for counting steps.

Adult↗
PubMed2006

A randomized controlled trial comparing the accuracy of general diagnostic upper gastrointestinal endoscopy performed by nurse or medical endoscopists.

BACKGROUND AND STUDY AIMS: Rising demand for general diagnostic upper gastrointestinal endoscopy in the UK is outgrowing the capacity of doctors to provide this service within a reasonable time. One solution is to train nurses to carry out the procedure, but it is not known whether nurses can perform general diagnostic upper gastrointestinal endoscopy as competently as doctors. PATIENTS AND METHODS: A randomized controlled non-inferiority trial compared the adequacy and the accuracy of diagnostic upper gastrointestinal endoscopies performed by five medical and two nurse endoscopists. The videotaped procedures were assessed by a consultant gastroenterologist blinded to the identity of the endoscopist. RESULTS: 641 patients were randomly allocated (before attendance and consent procedure) to endoscopy carried out either by a doctor or a nurse. Of these, 412 were enrolled and 367 (89 %) were included in the analysis. An adequate view was obtained throughout in 53.4 % (93/177) of doctor endoscopies and 91.6 % (174/190) of nurse endoscopies (difference 38.2 %, 95 % CL 30.5 %, 47.2 %). In adequately viewed areas, the mean agreement between doctor and expert was 81.0 % and between nurse and expert it was 78.3 % (difference between the means 2.7 %, 95 % CL - 1.0 %, 6.4 %). There was no difference between doctors and nurses in the rate of biopsy performance (90.4 % and 91.1 %, respectively, P = 0.862). Nurses took longer (8.1 minutes vs. 4.6 minutes, P < 0.001) and used intravenous sedation more often (57.6 %, P = 0.027). Adequacy of view correlated positively with endoscopy duration ( P < 0.001), but diagnostic accuracy correlated inversely with duration ( P < 0.001). Neither adequacy or accuracy correlated significantly with use of intravenous sedation. CONCLUSIONS: In endoscopies performed by nurses, the proportion of adequate examinations was much higher than that found for doctors. In areas with an adequate view, there is no significant difference in accuracy between nurses and doctors. Nurses can provide an accurate general diagnostic upper gastrointestinal endoscopy service as competently as doctors.

Clinical Competence↗
PubMed2006

[Improved accuracy and precision of the automated shaver (navigated control) in functional endoscopic sinus surgery].

BACKGROUND: The feasibility of a navigate-controlled Shaver for the paranasal sinus surgery was proven in an initial study. Deficits showed up in the conversion of the planed cavity. Goal of this study is (1) the development and evaluation of a FESS demonstrator for the investigations to the surgical accuracy and (2) the evaluation of the resulting surgical accuracy for registration and conversion of the work space with an improved rigidity of the Shaver and a completely revised study design. METHODS: As a demonstrator for the navigate-controlled resection of a volume through the Shaver a two-piece plastic head with an anatomical head and soft tissue model was designed. The investigation of the surgical accuracy takes place with 417 measurements to 4 different fiducial markers on the demonstrator head. The measurements for the deviation of the resulting cavity from the planned volume was realised with a work space by 24 x 24 x 30 mm. The 5 walls of the cavity were seized with 80 measuring points for each level and thus altogether 2000 measured values (5 models x 5 levels x 200 points). RESULTS: The described demonstrator showed itself suitable for the close-to-application attempts to the surgical accuracy. The maximum deviation A (max) indicated position of the Shaver from the reference value amounted to 1,93 mm. The maximum average value of the exceeding of a planned cavity amounts to 1,62 mm. CONCLUSIONS: Based on these results a virtual safety passage of 2.00 mm is sufficient. The study refers the clinical serviceability of the navigate-controlled Shaver in paranasal sinus surgery.

Equipment Design↗
PubMed1993

Influence of tumor stenosis on the accuracy of endosonography in preoperative T staging of esophageal cancer.

The T stage is an important criterion for determining prognosis in esophageal carcinoma. Endosonography, although established as a highly accurate method in preoperative determination of the T stage, may be less reliable in non-traversable tumor stenoses. In a comparative prospective study, 41 patients with carcinoma of the esophagus were investigated to determine the role of tumor stenosis on the accuracy of endosonography in preoperative T staging. The results were correlated with the histology of the resected specimen. The overall accuracy in T staging with endosonography was 76%, compared with 49% in computed tomography. T staging results of endosonography were good in easily and non-traversable stenoses (92%, 87% respectively), but lower accuracy was obtained in stenoses which could be traversed only with difficulty (46%). Computed tomography was inferior to endosonography in all three groups of patients. The high accuracy of endosonography in non-traversable stenoses might be due to the fact that all tumors were in an advanced stage (T3 or T4). When passage of the echoendoscope proves difficult, the low focal distance between the ultrasonic transducer and tumor may hamper clear visualisation of the wall layers and tumor penetration depth. These limitations of endosonography should stimulate further efforts in improving ultrasonic resolution in these cases.

Adenocarcinoma↗