Epidemiology of musculoskeletal upper extremity ambulatory surgery in the United States

Background

Musculoskeletal disorders of the upper extremity are common reasons for patients to seek care and undergo ambulatory surgery. The objective of our study was to assess the overall and age-adjusted utilization rates of rotator cuff repair, shoulder arthroscopy performed for indications other than rotator cuff repair, carpal tunnel release, and wrist arthroscopy performed for indications other than carpal tunnel release in the United States. We also compared demographics, indications, and operating room time for these procedures.

Methods

We used the 2006 National Survey of Ambulatory Surgery to estimate the number of procedures of interest performed in the United States in 2006. We combined these data with population size estimates from the 2006 U.S. Census Bureau to calculate rates per 10,000 persons.

Results

An estimated 272,148 (95% confidence intervals (CI)?=?218,994, 325,302) rotator cuff repairs, 257,541 (95% CI?=?185,268, 329,814) shoulder arthroscopies excluding those for cuff repairs, 576,924 (95% CI?=?459,239, 694,609) carpal tunnel releases, and 25,250 (95% CI?=?17,304, 33,196) wrist arthroscopies excluding those for carpal tunnel release were performed. Overall, carpal tunnel release had the highest utilization rate (37.3 per 10,000 persons in persons of age 45–64 years; 38.7 per 10,000 persons in 65–74 year olds, and; 44.2 per 10,000 persons in the age-group 75 years and older). Among those undergoing rotator cuff repairs, those in the age-group 65–74 had the highest utilization (28.3 per 10,000 persons). The most common indications for non-cuff repair related shoulder arthroscopy were impingement syndrome, periarthritis, bursitis, and instability/SLAP tears. Non-carpal tunnel release related wrist arthroscopy was most commonly performed for ligament sprains and diagnostic arthroscopies for pain and articular cartilage disorders.

Conclusions

Our data shows substantial age and demographic differences in the utilization of these commonly performed upper extremity ambulatory procedures. While over one million upper extremity procedures of interest were performed, evidence-based clinical indications for these procedures remain poorly defined.     

Presentation of cauda equina syndrome due to an intradural extramedullary abscess: a case report

Background contextCauda equina syndrome is caused by compression or injury to the nerve roots distal to the level of the spinal cord. This syndrome presents as low back pain, motor and sensory deficits in the lower extremities, and bladder as well as bowel dysfunction. Although various etiologies of cauda equina syndrome have been reported, a less common cause is infection.PurposeTo report a case of cauda equina syndrome caused by infection of an intradural extramedullary abscess with Staphylococcus aureus.Study design/settingCase report and review of the literature.MethodsThe literature regarding the infectious causes of cauda equina syndrome was reviewed and a case of cauda equina syndrome caused by infection of an intradural extramedullary abscess with Staphylococcus aureus was reported.ResultsA 37-year-old woman, with history of intravenous drug abuse, hepatitis C, and hepatitis B, presented with low back pain lasting 2 months, lower extremity pain, left greater than right with increasing weakness and difficulty ambulating, and urinary and fecal incontinence. Her presentation was consistent with cauda equina syndrome. The patient underwent a T12–L2 laminectomy, and intradural exploration revealed an abscess. Methicillin-resistant Staphylococcus aureus was found on wound culture.ConclusionsCauda equina syndrome, presenting as a result of spinal infection, such as the case reported here, is extremely rare but clinically important. Surgical intervention is generally the recommended therapeutic modality.     

Revealing the WEDM Process Parameters for the Machining of Pure and Heat-Treated Titanium (Ti-6Al-4V) Alloy

Ti-6Al-4V is an alloy that has a high strength-to-weight ratio. It is known as an alpha-beta titanium alloy with excellent corrosion resistance. This alloy has a wide range of applications, e.g., in the aerospace and biomedical industries. Examples of alpha stabilizers are aluminum, oxygen, nitrogen, and carbon, which are added to titanium. Examples of beta stabilizers are titanium–iron, titanium–chromium, and titanium–manganese. Despite the exceptional properties, the processing of this titanium alloy is challenging when using conventional methods as it is quite a hard and tough material. Nonconventional methods are required to create intricate and complex geometries, which are difficult with the traditional methods. The present study focused on machining Ti-6Al-4V using wire electrical discharge machining (WEDM) and conducting numerous experiments to establish the machining parameters. The optimal setting of the machining parameters was predicted using a multiresponse optimization technique. Experiments were planned using the response surface methodology (RSM) technique and analysis of variance (ANOVA) was used to determine the significance and contribution of the input parameters to changes in the output characteristics (cutting speed and surface roughness). The cutting speed obtained during the processing of the annealed titanium alloy using WEDM was quite large as compared to the cutting speed obtained in the case of processing the pure, quenched, and hardened titanium alloys using WEDM. The maximum cutting speed obtained while processing the annealed titanium alloy was 1.75 mm/min.     

Microwave-assisted facile synthesis of poly(luminol-co-phenylenediamine) copolymers and their potential application in biomedical imaging

Conjugated copolymers have attracted much attention because of their outstanding photo-physical properties. The present work reports for the first time, microwave-assisted copolymerization of o-phenylenediamine with luminol using different weight ratios of the two monomers. The composition of the copolymers was confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (¹H-NMR) while monomer reactivity ratios were determined using the Fineman–Ross method. Ultraviolet-visible spectroscopy revealed the variation in polaronic states upon copolymerization while X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses showed the morphology of the copolymers to be intermediate between that of the homopolymers. Confocal analysis and fluorescence studies revealed that the copolymers showed composition based blue as well as red emission which could be utilized for in vivo imaging of cancer cells.

Development of bioimaging agents based on poly(o-phenylendiamine and luminol).     

Normal Weight Obesity: An Underrecognized Problem in Individuals of South Asian Descent

PurposeObesity has attained pandemic proportions across the world, and its prevalence in developing countries is also on the rise. Nevertheless, there is still a large gap in understanding the reasons behind a disproportionately high prevalence of diabetes as opposed to a lesser degree of obesity seen in individuals of South Asian origin. This research letter highlights the importance of identifying individuals with normal weight obesity, which may partially bridge this knowledge gap.MethodsWe reviewed recently published evidence on normal weight obesity.FindingsNormal weight obesity is a common public health problem and may be prevalent in up to one-third of individuals of certain Asian ethnicities. Literature is emerging on its pathophysiology and association with metabolic diseases, such as type 2 diabetes mellitus, hypertension, and dyslipidemia. More recently, normal weight obesity was also identified as an independent strong predictor of cardiovascular mortality. However, evidence is particularly lacking on its appropriate management.ImplicationsNormal weight obesity is an underrecognized yet widely prevalent problem in individuals of Asian descent. Further research on pathogenic mechanisms, diagnostic modalities, and therapeutic options in individuals with normal weight obesity is needed to appropriately manage this condition.     

Unusual immunophenotype of CD8+ T cells in familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is an inherited, fatal disorder of infancy. We report here a 17-day-old female infant who presented with high fever, hepatosplenomegaly, hypertriglyceridemia, hypofibrinogenemia, thrombocytopenia, and liver failure. Leukocytosis was detected with circulating "atypical" lymphoid cells. Flow cytometric studies revealed expanded subpopulations of CD8+ T cells with unusual immunophenotypic features, including a subset that lacked CD5 expression. A liver biopsy showed hemophagocytic lymphohistiocytosis with exuberant infiltrates of CD8+ T cells that lacked perforin. Mutational studies revealed a 666C-->A (H222Q) missense mutation in the perforin gene. T-cell receptor studies on flow-sorted T-cell subpopulations revealed no evidence of monoclonality. Analysis of T-cell receptor excision circle levels indicated long proliferative history in the aberrant CD8+ T-cell subsets. This case provides an instructive example of uncontrolled reactive proliferation of CD8+ T cells in FHL, resulting in atypical morphology and unusual immunophenotypic features that might suggest malignancy in other clinical settings.     

Evidence for host-driven selection of the HIV type 1 vpr gene in vivo during HIV disease progression in a transfusion-acquired cohort

An epidemiologically linked HIV-1-infected cohort, in which a nonprogressor donor infected two recipients who progressed to AIDS, was examined. Sequence analysis, over time, of HIV-1 vpr gene quasispecies from uncultured peripheral blood cells revealed an insertion of arginine at position 90 altering a highly conserved C-terminal motif, believed to play a role in Vpr nuclear targeting. Full genome analysis from each patient showed no gene defects in other gene regions, implying that the mutational selection was unique to the vpr gene. A detailed analysis of the vpr quasispecies showed very little amino acid diversity in the nonprogressing donor, whereas, following viral transmission, the amino acid diversity increased dramatically over time in tandem with disease progression in the two recipients. Although the R insertion at position 90 was present in all three individuals, the variable degree of additional amino acid changes over time may have influenced HIV disease in the nonprogressor donor and the two progressing recipients. These data provide the first evidence in favor of vpr gene evolution over time, which was host-driven. The status of the nonprogressing donor was consistent with a highly protective B-57 HLA type, which was absent in the two progressing recipients, implying a role for host HLA type and other immunologic selective pressures in vpr gene selection in vivo.