Quantitative analysis of the functionality and efficiency of three surgical dissection techniques: a time-motion analysis.

The increasing technological complexity of surgery demands objective evaluation of surgical techniques. In particular, alternatives for laparoscopic ligation, such as monopolar coagulation and the relatively new bipolar scissors combining dissection with coagulation, should be analyzed and compared. This study tests the efficacy of quantitative time-motion analysis in evaluating and comparing the functionality and efficiency of dissection and ligation techniques in a clinical setting. Standard dissection with ligation of vessels, bipolar scissors, and monopolar coagulation were consecutively applied to dissect 4 of the small bowel mesentery of pigs, in random order. All actions performed were recorded and analyzed, using a standard action list. The efficiency of each technique was expressed in mean dissection time and number of actions, and the safety in occurrence of complications and severity of microscopic damage. Time-motion analysis evaluated the efficiency objectively and reproducibly (ICC 0.98). Bipolar scissors were significantly more efficient (time 7 +/- 2 min, actions 129 +/- 33) than the standard technique (28 +/- 6, 771 +/- 185) and monopolar coagulation (14 +/- 5, 368 +/- 32) (p < 0.01). Furthermore, bipolar coagulation needed significantly less recoagulation of an oozing vessel (0.5% of the total dissected vessels) than did monopolar coagulation (10.4%), and the damaged zone was significantly smaller (p < 0.05). Significantly less time was spent waiting or exchanging instruments with bipolar scissors than with the standard technique (p < 0.05). This time-motion analysis objectively compared the efficiency and functionality of three surgical dissection techniques during clinical use. Bipolar scissors were more efficient than were both other techniques, and they coagulated vessels more safely than did monopolar coagulation.     

The similarity of brain morphology in healthy monozygotic twins

Aim of the study was to investigate the degree of similarity of twin brains with respect to their outer shape and gyrification. High resolution MRI was obtained from 26 healthy monozygotic twins (MZ) and three-dimensional renderings of the brains were generated. Similarity was rated by human investigators and by computer analysis. Three different image types were analyzed: whole-brain views, silhouettes and a bird's-eye view of a segment showing the central region. For each of the three image types, 13 tasks (identifying the related twin-pair out of a set of five brains) had to be solved by the human raters. For whole brain, views and silhouettes 66/91(p<0.005) and for segment views 44/91 (p<0.02) correct identifications were made. Using cross correlation coefficients, the computer-based analysis as well significantly often identified related twins. Again correct identification was more likely based on whole-brain views and silhouettes than on segment views of the central region. In conclusion, we found that overall brain shape is probably strongly influenced by genetic effects but the variation in sulcal and gyral patterns is also affected by non-genetic influences to a considerable extent.     

Acute stroke patients are being underfed

Introduction: Patients with acute neurological illness may be hypercatabolic. The Harris-Benedict Equation (HBE) is used to estimate energy needs in acute stroke. A “stress factor” for stroke does not exist, and it is not known if the HBE accurately estimates the energy expenditure needs in acute ischemic or hemorrhagic stroke. We sought to assess nitrogen balance in patients with acute stroke and to determine the variables associated with negative nitrogen balance. Materials and Methods: This was a case series, single-center study. Eligibility criteria included acute stroke requiring enteral nutrition, tolerating tube feedings at goal, normal urine output, and no underlying catabolic illness. Enteral feeding was adjusted to meet HBE requirements. After 24 hours of goal feeding, a 12-hour urine collection for nitrogen excretion was done. We determined if any of the following variables were associated with negative nitrogen balance: gender, glucose 6.6 mmol/L or more, age 80 years or older, National Institutes of Health Stroke Scale (NIHSS) 20 or higher, mechanical ventilation, and diabetes mellitus. Results: We studied 27 patients (10 with intracranial hemorrhages and 17 with ischemic strokes) during an 18-month period. The median age was 80 (range: 48–90), and the median NIHSS was 19 (range: 4–38). The median time to feeding was 2 days (range: 1–8), the median time from onset to nitrogen balance was 5 days (range: 2–11), and the median interval between initiation of feeding and nitrogen collection was 2 days (range: 1–5) Negative nitrogen balance was seen in 12 of 27 (44%) patients. There was no relation between age, NIHSS, stroke type, admission glucose, history of diabetes, and mechanical ventilation use and nitrogen balance. Only 11 of 27 patients were anabolic. Conclusion: Critically ill stroke patients are being underfed using the current methods to estimate caloric needs. Hypercatabolism is common in acute stroke; clinical variables do not seem to allow prediction of this catabolic state.     

Stellenwert moderner CT-Techniken bei der Diagnostik des akuten Schlaganfalls

ZusammenfassungHintergrund Die intravenöse Thrombolyse ist die Behandlung der Wahl für akute Schlaganfallpatienten im 3-h-Zeitfenster. Metaanalysen zufolge besteht auch ein Behandlungseffekt jenseits der 3-h-Grenze, der aber kleiner ist (time is brain). Die Anwendung moderner bildgebender Verfahren kann die Patienten identifizieren, die am ehesten von einer Thrombolysetherapie auch außerhalb etablierter Zeitfenster profitieren. Moderne Schlaganfall-MRT-Protokolle sind der aktuelle Goldstandard für die akute Schlaganfalldiagnostik, sind im Gegensatz zu CT-basierter Diagnostik aber deutlich seltener verfügbar. Der Bedarf für eine optimierte CT-Diagnostik bei Schlaganfallpatienten ist offensichtlich.Methoden Grundlage dieses Übersichtsartikels ist eine ausführliche Sichtung der aktuellen Literatur über Schlaganfalldiagnostik. Die diagnostischen Stärken und Schwächen nativer CT-Techniken, von CT-Angiographie (CTA), CTA-Quellbildanalyse (CTA-QB) und Perfusions-CT (PCT) für die diagnostische Aufarbeitung akuter Schlaganfallpatienten werden kritisch reflektiert. Die Autoren präsentieren einen umfassenden diagnostischen Ansatz für akute Schlaganfallpatienten in Analogie zu Schlaganfall-MRT-Befunden, der es erlaubt, rigide Zeitfenster zu relativieren und das Patientenmanagement zu optimieren.Schlussfolgerung Der Nachweis oder Ausschluss einer intrazerebralen Blutung (ICB) mit der nativen CT und eines Gefäßverschlusses mit der CTA wird als obligatorisch für eine Thrombolyse außerhalb des 3-h-Fensters angesehen. Eine deutliche Hypodensität von mehr als 1/3 des Mediaterritoriums auf nativen CT-Bildern oder CTA-QB ist eine Kontraindikation für die Thrombolysetherapie. Der irreversibel geschädigte Infarktkern und die ischämische aber potenziell rettbare Penumbra können auf kombinierten CT/CTA/CTA-QB/PCT identifiziert werden und charakterisieren den idealen Thrombolysepatienten. Eine umfassende Aufklärung vor Einsatz der Thrombolyse außerhalb etablierter Zeitfenster ist notwendig.     

Reliability of left and right indicators in CT scanning of the head. Case report

A case is described in which incorrect preliminary programming of a computerized tomography (CT) machine caused transposition of the left- and right-side indicators in a CT scan, which led to craniotomy on the normal side. The possible mechanism for this is incorrect pre-scan programming of the CT scanner with respect to patient positioning in the scanner gantry. This error, although unlikely, is still possible with the present generation of CT scanners.     

Abdominal aortic aneurysms: diagnostic review and new technique.

A new technique of computed tomography (CT) applied to the diagnosis of abdominal aortic aneurysms is described, and the experience in 58 patients is reviewed. In all instances the abdominal aorta was clearly demonstrated, even when wall calcification was absent. A series of 37 patients with abdominal aortic aneurysm underwent evaluation by physical examination, abdominal roentgenograms, and ultrasonic and CT scanning. Measurements of the transverse diameter at the point of maximal dilatation were compared with the measurements made at operation. CT not only confirmed the diagnosis in all patients but the measurements obtained by this technique were the most accurate, correlating extremely well with the true dimensions of the aneurysm. The addition of contrast enhancement to CT scanning allowed clear delineation of the aortic lumen and intraaneurysmal thrombus, not possible with any other method, including ultrasonography. The technique appears useful as a screening procedure and in the differential diagnosis of a tortuous abdominal aorta. Patients with a small aortic dilatation can be followed accurately by scanning.     

Computed tomographic evaluation of aortic aneurysms.

Applications of computed tomography are being extended from the brain to other body parts. This report describes CT scanning of abdominal and thoracic aortic aneurysms in 30 patients. CT shows greatest promise in abdominal aortic scanning, where reliable identification of the aorta can be achieved even in the absence of enlargement or calcification. However, current limitations prevent visualization of internal detail such as intimal plaques or mural thrombi. Technical advances are described which should have an important bearing on this.