Technical aspects and access devices for preperitoneal and retroperitoneal endoscopic surgery

The main advantages of preperitoneal and retroperitoneal endoscopic surgery over conventional laparoscopy or open surgery are the decreased risk of injury to organs and reduced postoperative adhesion formation. Exact knowledge of anatomy, as well as correct positioning of the patient, is essential for its success. While a blunt dissection technique, using either the fingers or an endoscope under pneumodissection, is preferred for preperitoneal surgery, the introduction of a balloon dissection device directly into the retroperitoneal cavity simplifies this procedure for retroperitoneoscopy. Different general surgical procedures are described for preperitoneal (hernia) and retroperitoneal (adrenalectomy, neurectomy/ sympathectomy) surgery. Urological/gynaecological procedures (kidney, tumor biopsy, lymphadenectomy) are excluded from this review. In recent years, the number of possible preperitoneal and retroperitoneal surgical procedures has increased, mainly as a result of the development of commercially-available balloon trocars and balloon-tipped trocars, which create and maintain a working space.     

Digital amorphous silicon flat-panel detector radiography at different exposure doses versus mammography film: possibility of radiation dose reduction in detecting rheumatologic bone defects

Background: Radiographic examinations of the skeleton are the most commonly performed radiologic procedures, even outnumbering examinations of the chest. The imaging systems used in skeletal radiography must meet high standards in terms of contrast and spatial resolution to effectively visualize the high contrast between bone and soft tissue as well as fine bone structures.

Purpose: To determine the performance of amorphous silicon flat-panel detector radiography compared to mammography film in detecting rheumatologic bone defects at different exposure doses.

Material and Methods: The study enrolled 44 patients with known or presumed skeletal changes of the hand associated with inflammatory rheumatic diseases. Following a clinically indicated radiographic examination of the peripheral extremities using mammography film, a survey radiograph of one hand was taken in the posteroanterior (PA) view by digital radiography, at the same exposure dose and at a dose reduced to one quarter of the mammography film doses. Four independent radiologists scored the resultant images using the Sharp/van der Heijde and Ratingen scoring methods. The study received University of Cologne Ethics Committee and German Federal Radiation Protection Agency approval.

Results: Compared to mammography film, digital flat-panel detector radiography produced a significantly better image quality at identical uptake doses. A greater number of erosions were detected with the digital flat-panel detector than with mammography film at the same and at reduced doses.

Conclusion: Although the spatial resolution of the digital flat-panel system used in this study was poorer than mammography film, this was compensated for by its wider dynamic range and improved contrast resolution, even at the reduced dose.     

A new technique for establishing dry weight in hemodialysis patients via whole body bioimpedance

BACKGROUND: Quantitative techniques are necessary to achieve dry weight (DW) in patients with kidney failure. Bioimpedance spectroscopy (BIS) is a non-invasive method that determines the volume of body fluid compartments. The current work evaluates the use of BIS data in hemodialysis patients for the prediction of DW. METHODS: A new technique has been devised for the estimation of DW that involves the intersection of two slopes, slope normovolemia (SNV) and slope hypervolemia (SHV). These slopes characterize the variation in extracellular water (ECW) with body weight (BW) in the states of normovolemia and hypervolemia, respectively. SNV was established via measurements of ECW and BW in 30 healthy subjects. In a longitudinal study in new hemodialysis patients, successive reduction of post-dialysis weight (PDW) was attempted until clinical signs of normovolemia were presented. Measurements of ECW and BW that were acquired at the beginning of each treatment were used to determine SHV. RESULTS: SNV was found to be 0.239 L/kg and 0.214 L/kg for male and female healthy subjects, respectively. A significant DeltaPDW predicted by the new method (-4.98 kg) was highly correlated to the DeltaPDW achieved in the study (-5.85 kg, R = 0.839). Blood pressure was reduced (P < 0.001) and an 86% decrease in antihypertensive agents was achieved. CONCLUSION: The method of intersecting slopes (SHV with SNV) via BIS is a new method for the prediction DW. This approach will offer considerable improvement for the routine management of DW in the dialysis setting.     

Effect of calcium and vitamin D supplementation on bone mineral density in women aged 65–71 years: a 3-year randomized population-based trial (OSTPRE-FPS)

Summary  

The Osteoporosis Risk Factor and Prevention-Fracture Prevention Study (OSTPRE-FPS) was a randomized population-based open trial (n = 593). The supplementation group (n = 287) received daily cholecalciferol 800 IU + calcium 1,000 mg for 3 years while the control group (n = 306) received neither supplementation nor placebo. Daily vitamin D and calcium supplementation have a positive effect on the skeleton in ambulatory postmenopausal women.     

Role of drug efflux carriers in the healthy and diseased brain

The blood-brain barrier is a natural diffusion barrier, which expresses active carriers extruding drugs on their way to the brain back into the blood against concentration gradients. Whereas these so-called adenosine triphosphate-binding cassette (ABC) transporters prevent the brain entry of toxic compounds under physiological conditions, they complicate pharmacotherapies in neurological disease. Recent observations in animal models of ischemic stroke, drug-resistant epilepsy, and brain cancer showed that the prototype of ABC transporters, ABCB1, is upregulated on brain injury, deactivation of this carrier considerably enhancing the accumulation of neuroprotective, antiepileptic, and chemotherapeutic compounds. These studies provide the proof of concept that the efficacy of brain-targeting drugs may significantly be improved when drug efflux is blocked. Under clinical conditions, efforts currently are made to enhance drug accumulation by selecting new compounds that do not bind to efflux carriers or deactivating ABC transporters by targeted downregulation or pharmacological inhibition. We predict that strategies aiming at circumventing drug efflux may greatly facilitate progress in neurological therapies.     

Effects of N-acetylcysteine on renal hemodynamics in contrast media-induced nephropathy

Background: N-acetylcysteine (NAC) has been proposed to prevent radiocontrast nephropathy in high-risk patients. Methods: The effect of single-dose and prolonged administration of NAC before application of either the ionic, high-osmolar radiocontrast agent diatrizoate sodium (DTZ) or the nonionic, low-osmolar radiocontrast agent iohexol (IOH) in a rat model combining uninephrectomy, salt depletion, and administration of indomethacin was explored. Arterial blood pressure and total, cortical, and medullary blood flow were continuously recorded in anesthetized Sprague-Dawley rats. Results: NAC had no effect on renal hemodynamics in control rats. Both DTZ and IOH induced biphasic changes in renal blood flow and cortical renal blood flux and persistently reduced medullary blood flux. Neither single-dose nor prolonged administration of NAC prevented the hemodynamic changes following administration of DTZ or IOH, respectively. Acute prophylactic administration of NAC prevented increased urinary ET excretion after injection of IOH and, to a smaller degree, of DTZ. Both an ionic, high-osmolar (DTZ) and a nonionic, low-osmolar (IOH) radiocontrast agent induce marked changes in renal hemodynamics in salt-depleted rats treated with indomethacin. Conclusions: Renal perfusion is not affected by NAC application in a model of experimental contrast nephropathy in rats. Other effects of NAC might thus account for the presumed renoprotective properties.     

Anatomical and surgical study of volume determination of the anterolateral epidural space nerve root L5/S1 under the aspect of epidural perineural injection in minimal invasive treatment of lumbar nerve root compression

Herniated intervertebral disc causes in a great number of cases of lumbar nerve root compression, especially in the segment L5/S1. Other reasons responsible for stress to the lumbar spinal root are the spinal canal stenosis and the postdiscotomy syndrome. For patients without neurological deficiencies, the conservative treatment includes different epidural injection techniques. Steroids are often applied. A specific injection technique needing only a small drug amount is the epidural perineural approach using a special two-needle technique. The anatomical spaces of the nerve roots have received little attention in therapy. We have determined the anterolateral epidural space nerve volume of the nerve root L5/S1, and compared the data collected in an anatomical study with operative measurements during discectomy. The volume determination in the human cadavers was performed with liquid silicone filling the anterolateral space after dissection. The in vivo measurements were performed during surgery at the site of the anterolateral space after discectomy. The anatomical studies showed us a mean value volume of 1.1 ml. The surgical volume determinations result in a mean volume of 0.9 ml. A better understanding of the anterolateral epidural space may allow a reduction of the injection volume in the conservative nerve root compression treatment, especially using the epidural perineural technique, avoiding the risk of side effects of high doses of steroids.     

Reproducibility and agreement of micro-CT and histomorphometry in human trabecular bone with different metabolic status

The use of micro-computed tomography (micro-CT) to study bone microstructure is continuously increasing. Thus, it is important to ensure that micro-CT can differentiate healthy and pathological bone. This study aimed to determine whether the reproducibility of bone histomorphometry and micro-CT, and agreement between the techniques, vary in bone samples with different metabolic status. Iliac crest biopsies (n = 36) were obtained from healthy subjects (n = 10) and from patients with osteoporosis (OP) (n = 15) or renal osteodystrophy (ROD) (n = 11). Micro-CT and histomorphometry analyses were repeated twice. Results were analyzed in separate groups and after pooling the data. Bone histomorphometry detected generally known differences between the diseases, whereas micro-CT did not detect differences between normal and ROD samples as effectively. Repeated measurements for BV/TV, Tb.Th, Tb.N, and Tb.Sp exhibited linear correlation coefficients (ρ) of 0.87–0.92 [coefficients of variations (CV), 8.3–27.2%] for histomorphometry and of 0.66–0.94 (CV, 4.4–23.4%) for micro-CT. There were no significant differences in reproducibility among samples from different study groups. Correlations between BV/TV (micro-CT) and mineralized bone volume (Md.V/TV, histomorphometry) were weaker than between BV/TV (micro-CT) and BV/TV (histomorphometry). When comparing the techniques, BV/TV, Tb.Th, and Tb.N displayed moderate correlations (ρ = 0.39–0.62, P < 0.05), and the agreement for BV/TV was highest in OP samples. The agreement between the techniques using clinical bone samples was moderate. Especially, micro-CT was less effective than bone histomorphometry in differentiating ROD from normal samples. The reproducibility was not affected by the health status of bone. Histomorphometry is still needed in clinical practice to study the remodeling balance in bone, and the methods are complementary.     

Does mini‐incision donor nephrectomy improve quality of life in living kidney donors?

BACKGROUND: Living kidney donation helps to avoid or reduce the time period of dialysis and on waiting lists in patients requiring a new organ. Mini-incision donor nephrectomy (MIDN) shows to result in better clinical outcome in comparison with traditional open donor nephrectomy (ODN). This study was performed to evaluate the impact of different surgical procedures on the quality of life (QoL) in patients that underwent donor nephrectomy. METHODS: The aim of the study was to detect differences in QoL assessed with the Short Form-36 Version 2 (SF-36v2) questionnaire between MIDN (n = 34) and ODN (n = 36). Furthermore, the development of QoL from prior to surgery until one yr afterwards, as well as outcomes of QoL in comparison with norm-based scores was investigated. RESULTS: Sixty-one of 70 patients, which is 87% (MIDN: 86%, ODN: 88%) resent a whole set questionnaires. QoL was similar at all time-points (prior to surgery, one wk, three months and one yr) in both groups. A tendency of better QoL in MIDN (Bodily Pain) after one wk was detectable (p = 0.075). Physical Component Summaries (PCS) significantly decreased from prior to surgery until one wk after surgery (p = 0.001) and improved significantly until three months (MIDN: p = 0.006, ODN: p = 0.001) and also until one yr after surgery (p = 0.002). Mental Component Summaries (MCS) were stable throughout the whole investigated time period. In comparison with norm-based scores, MIDN (p = 0.005) and ODN (p = 0.001) showed significantly higher PCS prior to, lower scores one wk after (p = 0.001), similar scores three months after and better scores (MIDN: p = 0.023, ODN: 0.015) one yr after surgery. Mental Component Scores were similar in both prior to and one wk after surgery. After three months and one yr scores were significantly better in MIDN (three months: p = 0.049, one yr: p = 0.037) and ODN (three months: 0.020, one yr: 0.073). CONCLUSION: Quality of life after living donor nephrectomy is not influenced by the surgical technique. Nevertheless the standardized instrument of the SF-36v2 Health Survey is a useful, practicable and universally interpretable tool to gain and estimate recovery from surgical procedures in the perioperative period and its development thereafter.