Bariatric Surgery and Effects on Calcium and Bone Metabolism

With the increasing epidemic of obesity in the United States as well as abroad, bariatric surgery has emerged as the most effective and sustained treatment for reduction. This treatment modality has been well recognized to diminish the risk of cardiovascular morbidity and mortality and ameliorate diabetes mellitus. However, with time, derangement in mineral metabolism has emerged as a major complication in this population. Population-based study has shown increased prevalence of bone fractures and kidney stone formation following bariatric surgery. The risk appears to be more specific after Roux-en-Y gastric bypass procedures, the most common surgical approach among this population. Over the past decade, there have been advances in the understanding of pathophysiologic mechanisms of both bone loss and kidney stone disease in these patients. The understanding of these underlying pathophysiologic mechanisms may lead to the development of drug therapies that ameliorate this complication. Unfortunately, at the present time, there is no hard data on any specific treatment showing decreased incidence of fragility fractures or kidney stone passage. However, some studies suggest that calcium and vitamin D supplementation may decrease bone loss and bone turnover, and as a result, increase bone mineral density in this population. However, there is concern with the development of kidney stone formation following such an approach. A novel treatment approach would be the use of effervescent potassium calcium citrate that not only prevents complications of bone loss but may diminish the risk of kidney stone formation. Despite preliminary results showing the effectiveness of this drug in the reduction in the parathyroid hormone, bone turnover, and improvement in the urinary saturation marker showing effectiveness against calcium oxalate and uric acid stones, there is no hard data available to support the effectiveness of this treatment in the reduction in fragility fractures or kidney stone incidence. Such studies to explore this effect must be considered in the future.     

CLINICAL Review #: the role of receptor activator of nuclear factor-kappaB (RANK)/RANK ligand/osteoprotegerin: clinical implications

CONTEXT: Receptor activator of nuclear factor-kappaB ligand (RANKL), receptor activator of nuclear factor-kappaB (RANK), and osteoprotegerin (OPG) play a central role in bone remodeling and disorders of mineral metabolism. EVIDENCE ACQUISITION: A PubMed search was conducted from January 1992 until 2007 for basic, observational, and clinical studies in subjects with disorders related to imbalances in the RANK/RANKL/OPG system. EVIDENCE SYNTHESIS: RANK, RANKL, and OPG are members of the TNF receptor superfamily. The pathways involving them in conjunction with various cytokines and calciotropic hormones play a pivotal role in bone remodeling. Several studies involving mutations in the genes encoding RANK and OPG concluded in the discovery of a number of inherited skeletal disorders. In addition, basic and clinical studies established a consistent relationship between the RANK/RANKL/OPG pathway and skeletal lesions related to disorders of mineral metabolism. These studies were a stepping stone in further defining the role of the RANK/RANKL/OPG pathway in osteoporosis, rheumatoid arthritis, bone loss associated with malignancy-related skeletal diseases, and its relationship to vascular calcifications. Subsequently, the further understanding of this pathway led to the development of new therapeutic modalities including the human monoclonal antibody to RANKL and recombinant OPG as a target for treatment of postmenopausal osteoporosis and multiple myeloma. CONCLUSIONS: The RANK/RANKL/OPG system mediates the effects of calciotropic hormones and, consequently, alterations in their ratio are key in the development of several clinical conditions. New agents with the potential to block effects of RANKL have emerged for treatment of postmenopausal osteoporosis and malignancy-related skeletal disease.     

Marginal adaptation of zirconia complete-coverage fixed dental restorations made from digital scans or conventional impressions: A systematic review and meta-analysis

Statement of problemIntraoral scanners have been increasingly used in recent years. However, the accuracy of digital scans as it affects marginal adaptation is unclear.PurposeThe purpose of this systematic review and meta-analysis was to compare the marginal adaptation of single-unit zirconia crowns fabricated with digital scans or with conventional impressions.Material and methodsThe electronic databases PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science (ISI), Scopus, and EMBASE were searched and complemented by a manual search. Risks of bias were assessed by using a modified methodological index for nonrandomized studies (MINORS). Mean ±standard deviation (SD) values of marginal accuracy of studies were extracted for both methods. Mean marginal difference and 95% confidence interval (CI) were calculated to evaluate the marginal accuracy of each method. Pooled data were statistically analyzed by using a random-effect model.ResultsSeventeen studies were used to perform the meta-analysis. Subgroup analysis was performed based on intraoral scanners. Standardized mean marginal difference and 95% CI of each subgroup were as follows: Lava: -0.85 μm (95% CI: -1.67, -0.03) (P=.043); CEREC: -1.32 μm (95% CI: -2.06, -0.59) (P<.001); iTero: -0.44 μm (95% CI: -1.35, 0.47) (P=.338); TRIOS: -1.26 μm (95% CI: -2.02, -0.51) (P=.001); unknown scanner: -0.21 μm (95% CI: -1.14, 0.72); all studies: -0.89 μm (95% CI: -1.24, -0.54) (P<.001).ConclusionsDigital scanning of prepared teeth for single-unit zirconia restorations resulted in better marginal accuracy than conventional techniques using elastomeric impression materials.     

Hand-assisted Laparoscopic Colorectal Surgery: Initial Experience of a Single Surgeon

Background/Aim:

As totally laparoscopic colorectal surgery is considered challenging and technically demanding with a long steep learning curve, we adopted hand-assisted laparoscopic colorectal surgery as a bridge to totally laparoscopic assisted colorectal surgery. This prospective study aims to highlight the initial experience of a single surgeon with this technique.

Materials and Methods:

A prospective analysis of the first 25 cases of hand-assisted laparoscopic colorectal resections which were performed by a single surgeon over a 15-month period. There were 15 males and 10 females with a mean age of 55.5 (range 20-82) years.

Results:

The indication in majority of cases was cancer (76%). The procedures consisted of 18 (72%) various colectomies and 7 (28%) anterior resections. The operative time ranged between 110-400 (mean 180) min. There was one conversion (4%) and the mean operative blood loss was 80 (range 60-165) ml. The number of lymph nodes retrieved in the cancer cases was 5-31 (mean 15) nodes. The mean length of hospital stay was five (range 3-10) days. The total number of short-term complications was six (24%) and there was one death due to anastomatic leak and multiorgan failure. Long-term complications after a maximum follow up of 30 months were two incisional hernias at the hand port site, but none of the patients developed adhesive small bowel obstruction or late anastomotic stricture. Currently all our colorectal procedures are conducted laparoscopically.

Conclusion:

Hand-assisted laparoscopic colorectal procedures are easy to learn as a good bridge to master totally laparoscopic colorectal surgery.     

Contrast-enhanced digital mammography

CEDM is a recent development of digital mammography using the intra-venous injection of an iodinated contrast agent in conjunction with a mammography examination. Two techniques have been developed to perform CEDM examinations: the temporal subtraction technique with acquisition of high-energy images before and after contrast medium injection and the dual energy technique with acquisition of a pair of low and high-energy images only after contrast medium injection. The temporal subtraction technique offered the possibility to analyze the kinetic curve of enhancement of breast lesions, similarly to breast MRI. The dual energy technique do not provide information about the kinetic of tumor enhancement but allows the acquisition of multiples views of the same breast or bilateral examination and is less sensitive to patient motion than temporal CEDM. Initial clinical experience has shown the ability of CEDM to map the distribution of neovasculature induced by cancer using mammography. Moreover, previous studies have shown a superiority of MX+CEDM, either for the assessment of the probability of malignancy than for BIRADS assessment comparing to MX alone. The potential clinical applications are the clarification of mammographically equivocal lesions, the detection of occult lesions on standard mammography, particularly in dense breast, the determination of the extent of disease, the assessment of recurrent disease and the monitoring of the response to chemotherapy. CEDM should result in a simple way to enhance the detection and the characterization of breast lesions.     

Eczema in loco minoris resistentiae

Eczema is a common skin condition of varied pathophysiology. Despite being common, under some circumstances, this diagnosis may be missed due to the presence of other more obvious signs—namely the presence of surgical scars.     

After more than 300 defibrillation shocks,patient still alive 12 years later refractory torsade de pointes due to polypharmacy and persistent vomiting

Acquired torsade de pointes ventricular tachycardia (TdP) is a rare but serious life-threatening arrhythmia caused by an array of cardiac and non-cardiac drugs. It is often refractory to pharmacological therapy and may result in death or require frequent defibrillations. In our case study a young female patient with no underlying heart disease developed very frequent sustained TdP requiring frequent defibrillations without which she would have certainly died. The ventricular arrhythmia in this patient was of multifactorial origin – cisapride, drug–drug interaction and persistent vomiting resulting in electrolyte disturbance and malnutrition. The patient survived after more than 300 defibrillation shocks over a period of 5 days and she is still alive 12 years later.