Target-controlled infusion during MitraClip procedures in deep-sedation with spontaneous breathing.

OBJECTIVE: Percutaneous mitral valve repair with the MitraClip system is an alternative procedure for high-risk patients not suitable for conventional surgery. The MitraClip can be safely performed under general anesthesia (GA) or deep sedation (DS) with spontaneous breathing using a combination of propofol and remifentanil. This study aimed to evaluate the benefits of target-controlled infusion (TCI) of remifentanil and administration of propofol during DS compared with manual administration of total intravenous anesthesia (TIVA) medication during GA in patients undergoing MitraClip. We assessed the impact of these procedures in terms of remifentanil dose, hemodynamic profile, adverse events, and days of hospital stay after the process. PATIENTS AND METHODS: From March 2013 to June 2015 (mean age 73.5 ± 9,54), patients underwent transcatheter MitraClip repair, 27 received DS via TCI and 27 GA with TIVA. RESULTS: Acute procedural success was 100%. DS-TCI group, in addition to a significant reduction of remifentanil dose administrated (249 µg vs. 2865, p < 0.01), resulted in a decrease in vasopressor drugs requirement for hemodynamic adjustments (29.6% vs. 63%, p = 0.03) during the procedure and a reduction of hypotension (p = 0.08). The duration of postoperative hospitalization did not differ between the two groups (5.4 days vs. 5.8 days, p = 0.4). CONCLUSIONS: Administration of remifentanil by TCI for DS in spontaneously breathing patients offers stable anesthesia conditions, with a lower amount of drugs, higher hemodynamic stability, and decreased side effects.

Influence of sternal size and inadvertent paramedian sternotomy on stability of the closure site: a clinical and mechanical study.

BACKGROUND: The influence of sternal size and of inadvertent paramedian sternotomy on stability of the closure site is not well defined. METHODS: Data on 171 consecutive patients undergoing cardiac surgery through a midline sternotomy were prospectively collected. Intraoperative measurements of sternal dimension included thickness and width at the manubrium, the third and fifth intercostal spaces; paramedian sternotomy was defined as width of one side of the sternum equaling 75% or more of the entire width, at any of the three levels. The chest was closed with simple peristernal steel wires and inspected to detect deep wound infection and/or instability for 3 postoperative months. The sternal factors and several patient/surgery-related factors were included in a multivariate analysis model to identify factors affecting stability. An electromechanical traction test was conducted on 6 rewired sternal models after midline or paramedian sternotomy and separation data were analyzed. RESULTS: Chest instability was detected in 12 (7%) patients and wound infection in 2 (1.2%). Patient weight (P = .03), depressed left ventricular function (P = .04), sternum thickness (indexed to body weight, P = .03), and paramedian sternotomy (P = .0001) were risk factors of postoperative instability; paramedian sternotomy was the only independent predictor (P = .001). The electromechanical test showed more lateral displacement of the two rewired sternal halves after paramedian than midline sternotomy (P = .002); accordingly, load at fracture point was lower after paramedian sternotomy (220 +/- 20 N vs 545 +/- 25 N, P = 0.001). CONCLUSIONS: Inadvertent paramedian sternomoty strongly affects postoperative chest wound stability independently from sternal size, requiring prompt reinforcement of chest closure.

Is fractal geometry useful in medicine and biomedical sciences?

Fractal geometry has become very useful in the understanding of many phenomena in various fields such as astrophysics, economy or agriculture and recently in medicine. After a brief intuitive introduction to the basis of fractal geometry, the clue is made about the correlation between Df and the complexity or the irregularity of a structure. However, fractal analysis must be applied with certain caution in natural objects such as bio-medical ones. The cardio-vascular system remains one of the most important fields of application of these kinds of approach. Spectral analysis of the R-R interval, morphology of the distal coronary arteries constitute two examples. Other very interesting applications are founded in bacteriology, medical imaging or ophthalmology. In our institution, we apply fractal analysis in order to quantitate angiogenesis and other vascular processes.

Dynamic study of the extraembryonic vascular network of the chick embryo by fractal analysis.

Fractal analysis is widely used in many scientific fields, including the study of vascularization. It is a convenient method that defines the complexity of natural structures. The chorioallantoic membrane of the chick embryo is a standard experimental model for the study of vasculogenesis and angiogenesis. The aim of this investigation was to demonstrate that fractal geometry is more appropriate than any other method to describe and analyse the evolution of a vascular network, i.e. the extraembryonar vascular network of the chick embryo. We used an original methodology to evaluate the complexity of this network in the first stages of embryo development (day 3 until 6). We demonstrated an increase of fractal dimension, indicating an increasing complexity of the vascular tree, until an asymptotical value of about 1.70 at day 4. The fractal approach is more accurate than other usual semi-quantitative or quantitative methods evaluating the complexity of a growing vascular tree.

Pilomatrix carcinoma.

A 43-year-old man presented with a tumour of the medial part of the right eyebrow. A biopsy was performed and histological examination revealed a malignant transformation of a 'calcifying epithelioma of Malherbe'. A secondary wide excision was performed. Clinical and pathological findings of this extremely rare tumour are reviewed. Factors influencing the prognosis are proposed, based on a compilation of the literature.

Verrucous carcinoma of the nasal septum and columella.

Tumours of the nasal septum are rare. They mostly concern squamous cell carcinomas. Verrucous carcinomas are exceptional, with only three well-documented cases in the literature. We operated such a tumour, localized both on the columella and nasal septum.

The distally based lateral arm flap for intraoral soft tissue reconstruction.

BACKGROUND: The radial forearm flap is probably the most frequently used among free flaps for intraoral soft tissue reconstruction. However, this flap is not always available. The other fasciocutaneous flaps may be too bulky or less pliable or may have a short vascular pedicle; their use is therefore less than ideal. We present a variant of the lateral arm flap located distally to the lateral epicondyle and having the same advantages as the radial forearm flap. METHODS: Vascular study (dissection and radiography) was previously undertaken to determine the vascular anastomotic network in the epicondylar area, between the posterior radial collateral artery and recurrent arteries running in front of the lateral epicondyle. This demonstrated the possibility of taking a skin paddle on and below the lateral epicondyle, based on the proximal pedicle. RESULTS: We used this flap on three patients for intraoral soft tissue reconstruction (tonsil, floor of the mouth, and piriform sinus). No complication with the flap itself was encountered. In all cases, direct closure of the donor site was possible, with no local complication. CONCLUSION: The distal lateral arm flap (LAF) represents an interesting and reliable alternative to the fasciocutaneous radial forearm flap. The positioning of the skin paddle over the lateral epicondyle and the proximal third of the lateral aspect of the forearm increases pedicle length, thus avoiding the use of vein grafts. Dissection is straightforward with a reliable vascular anatomy. Moreover, in this area, the limited amount of subcutaneous fatty tissue ensures easier placement and more pliability when compared with the standard LAF.

Iatrogenic posterior interosseous nerve palsy following an elbow fracture.

Posterior interosseous nerve palsy following elbow surgery is not uncommon. Nevertheless, precise etiology of the palsy is rarely described in the literature. In this paper the possible causes of the posterior interosseous nerve palsy are reviewed and an uncommon iatrogenic lesion after surgical treatment of an elbow fracture is reported.

Aggressive basal cell carcinoma of head and neck areas.

Among skin cancers, basal cell carcinoma (BCC) is considered as a relatively indolent disease. Sometimes, these carcinomas have an unusual clinical behaviour, with extreme aggressiveness. Based on reports of eight cases of aggressive BCC of the head and neck areas, and after a review of the literature, we define three criteria of aggressiveness: (1) initial diameter greater than 1 cm, (2) more than two recurrences despite all tentative conclusions of adequate treatment, or (3) extension into any extracutaneous structure.

Free TRAM flap for lower-extremity reconstruction.

The usefulness of TRAM flaps is well-established. Their use in soft-tissue reconstruction of the lower limbs is illustrated. The flaps allow coverage of soft-tissue defects with good quality skin, and add bulk to enhance leg contour. Three cases are presented, and the advantages of this flap are discussed.

New concepts in the study of tissue vascularization: a mathematical model of skin vascularization.

A preliminary study demonstrated the existence of a fractal structure for perforator arterial vessels of the skin and proved to be a useful tool to compare vascular trees on the basis of their complexity. Fractal analysis of axial-perforator arteriovenous vascular trees was performed on the skin of mice after injection of the arterial network by india ink. Fractal analysis was performed by box counting. Fractal dimension D was determined for 35 venous and 31 arterial perforator vessels (D = 1.302 and 1.264, respectively) and 5 venous and 3 arterial axial vessels (D = 1.374 and 1.328, respectively) (r2 > or = 0.985). All vascular networks show a fractal structure, characterized by a specific D. These values are relatively constant; D is a function of the anatomic and physiologic characteristics. There was no significant difference between venous and arterial networks, nor was there between axial and perforator networks (p < 0.05); this demonstrates a similar efficacy in terms of perfusion of the skin. A computer simulation based on fractal theory has been developed to reproduce the two kinds of vascular networks. Fractals are the result of a construction procedure that is repeated and repeated so that the iteration of a very simple rule can produce seemingly complex shapes, such as vascular networks. The basic module that is repeated in the whole structure is Y-shaped and is termed the generator; this generator is applied to a basic structure, called the initiator. After a few iterations, a vascular network is obtained. The difference between axial and perforator vascular networks is the choice of the initiator, whereas the generator is identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical training in Belgium: evaluation by residents.

A survey has been made among the residents in order to assess the quality of the training in surgery in Belgium. The results of the answers to the questionnaire are presented. Suggestions are made with the aim of enhancing the quality of the training programs.

Training in surgery: our constructive propositions.

Several suggestions are presented in order to achieve or to maintain a level of excellence in surgical training, i.e. 1. Interuniversity theoretical teaching; 2. National evaluation; 3. Effective limitation of the number of residents; 4. Residents must be represented in critical organs; 5. A yearly evaluation of the quality of training. These requirements are fulfilled in the USA and Canada.

Clinical experience with the reverse lateral arm flap in soft-tissue coverage of the elbow.

Coverage of soft-tissue defects of the posterior aspect of the elbow is a difficult problem. Many techniques have been published, mostly case reports. The radial recurrent fasciocutaneous flap as described by Maruyama and Takeuchi represents one of the best solutions for medium-sized defects. We used it successfully in five clinical cases. The anatomy of this flap, based on the radial recurrent artery, has been confirmed by our cadaver studies, and a technique to raise this flap safely will be described.

A new approach to the study of skin vascularization.

There are several methods of quantifying the vascularization of tissues, including the skin, but they are imprecise in terms of quantification of the complexity and structure of vascular networks. Fractal analysis can quantify the complexity of any structure existing in nature by using fractional dimension. This study makes a case for this approach by demonstrating the fractal structure of the skin vascular network in the mouse. The skin was removed from the posterior face of the thigh, which is supplied by a musculocutaneous perforator system. Twenty arterial vascular networks were investigated by image analysis and the fractal dimension was determined by the box counting method. Statistical analysis revealed an average mean of fractal dimension D = 1.256 (SD = 0.086), indicating low to intermediate complexity with a narrow distribution of results. D should logically fluctuate within a certain limit, depending on the anatomical structure investigated and its physiological function. These results demonstrate the ability of fractal analysis to quantify the vascular pattern of the skin. Fractal analysis opens a new field of investigation in the study of vascularization patterns and possible vascular modification by different physiological or pathological conditions (flap-delay techniques, tobacco use, diabetes mellitus, classification of diabetic retinopathies).

Determination of lactate threshold by respiratory gas exchange measures and blood lactate levels during incremental load work.

OBJECTIVE: The purpose of this investigation was the determination of the lactate threshold (LT) by selected respiratory gas exchange measures and venous blood lactate levels during incremental load work on a mechanically braked cycle ergometer. DESIGN: Repeated measures design. SETTING: Human Performance Laboratory. PARTICIPANTS: Eight healthy trained soccer players (mean age 21.9 +/- 3.0 yr, mean VO2max = 59.2 +/- 3.6 ml.kg.min-1). OUTCOME MEASURE: Subjects conducted two incremental load work tests. Incremental load work was increased by 1 kilopond (kp) every third minute at 60 rpm until voluntary exhaustion. Blood samples from a forearm vein were collected during the second trial (T2) only and analyzed for lactic acid [LA-]. RESULTS: One-way analysis of variance (ANOVA) with repeated measures indicated no statistically significant difference between the two tests for maximal oxygen uptake (VO2max), maximal carbon dioxide production (VCO2max), maximal heart rate (HRmax), maximal pulmonary ventilation (VEBTPSmax) and lowest ventilatory equivalent of oxygen (VE/VO2), respectively; however, there was a significant difference among the oxygen uptake (VO2) values at the LT for the four determination methods. In our subjects, the measured (mean +/- SD) VE/VO2 in relation to VO2 for the first trial (T1) of 22.9 +/- 1.9 occurred at VO2 of 1.27 +/- 0.8 l.min-1. The lowest VE/VO2 and the onset of [LA-] accumulation calculated from individual exponential equations relating VE to VO2 yielded VO2 values of 1.77 +/- 0.18 and 1.74 +/- 0.25 l.min-1 for the T2. Utilizing natural log for lactate ln [LA-] to natural log for ln (VO2) equations, the LT for T2 occurred at VO2 of 1.30 +/- 0.70 l.min-1. CONCLUSION: LT was best predicted by the measured lowest VE/VO2 and the plot of the ln [LA-] to ln VO2 relationship. The methods used in this study provide a valid estimate of the LT and support the use of measured lowest VE/VO2 as an indirect measure of the LT.

Interrelationship between plasma potassium concentration, pulmonary ventilation and electrocardiographic change during and after highly intense exercise.

OBJECTIVE: The purpose of this investigation was to induce elevated plasma concentrations of potassium (K+) efflux from active muscle cells during intense muscular exercise. The relationship between K+, pulmonary ventilation (VE) and EKG changes, specifically T-wave amplitude, is presently controversial. DESIGN: Repeated measures design. SETTING: Human performance laboratory. PARTICIPANTS: Twelve volunteer trained recreational cyclists (10 males, mean age 31.9 +/- 7.4, and 2 females, mean age 27.5 +/- 0.7, mean VO2max 571.2 +/- 6.4 ml.kg.min-1). OUTCOME MEASURE: Subjects performed 10 min of pedaling at 90 rpm, yielding a power output of 45 W.min-1 on a mechanically braked cycle ergometer as a warm-up. Each exercise stage was 2 min in duration, beginning at 135 W and increased by 45 W thereafter until voluntary exhaustion. Respiratory gas exchange measures were obtained every 10 sec. Venous blood samples for K+ and lactate (LA-) determination were drawn at rest, at the end of stage 2, all subsequent stages, and during 3 and 10 min of recovery. EKG recordings were concurrent with venous sampling. RESULTS: Statistical analyses for VE vs. K+, respiratory exchange ratio (RER) vs. K+ and RER vs. LA- revealed neither significant change nor an associative relationship from stages 1-3. However, stages 4-8 were statistically significant (p < .05) and highly correlated. No relationship was found between K+ change and T-wave amplitude during exercise or recovery. CONCLUSION: These data indicate a strong relationship between selected respiratory gas exchange measures and K+ during intermediate to highly intense exercise.