On the analysis of hybrid designs that combine group- and individual-level data.

Ecological studies that make use of data on groups of individuals, rather than on the individuals themselves, are subject to numerous biases that cannot be resolved without some individual-level data. In the context of a rare outcome, the hybrid design for ecological inference efficiently combines group-level data with individual-level case-control data. Unfortunately, except in relatively simple settings, use of the design in practice is limited since evaluation of the hybrid likelihood is computationally prohibitively expensive. In this article we first propose and develop an alternative representation of the hybrid likelihood. Second, based on this new representation, a series of approximations are proposed that drastically reduce computational burden. A comprehensive simulation shows that, in a broad range of scenarios, estimators based on the approximate hybrid likelihood exhibit the same operating characteristics as the exact hybrid likelihood, without any penalty in terms of increased bias or reduced efficiency. Third, in settings where the approximations may not hold, a pragmatic estimation and inference strategy is developed that uses the approximate form for some likelihood contributions and the exact form for others. The strategy gives researchers the ability to balance computational tractability with accuracy in their own settings. Finally, as a by-product of the development, we provide the first explicit characterization of the hybrid aggregate data design which combines data from an aggregate data study (Prentice and Sheppard, 1995, Biometrika 82, 113-125) with case-control samples. The methods are illustrated using data from North Carolina on births between 2007 and 2009.

HCC patients suffer less from geographic differences in organ availability.

It has been suggested that the number of exception model for end-stage liver disease (MELD) points for hepatocellular carcinoma (HCC) overestimates mortality risk. Average MELD at transplant, a measure of organ availability, correlates with mortality on an intent-to-treat basis and varies by donation service area (DSA). We analyzed Scientific Registry of Transplant Recipients data from 2005 to 2010, comparing transplant and death parameters for patients transplanted with HCC exception points to patients without HCC diagnosis (non-HCC), to determine whether the two groups were impacted differentially by DSA organ availability. HCC candidates are transplanted at higher rates than non-HCC candidates and are less likely to die on the waitlist. Overall risk of death trends downward by 1% per MELD point (p = 0.65) for HCC, but increases by 7% for non-HCC patients (p < 0.0001). The difference in the change of mortality with MELD is statistically significant between HCC and non-HCC candidates p < 0.0001. Posttransplant risk of death trends downward by 2% per MELD point (p = 0.28) for HCC patients, but increases by 3% per MELD point in non-HCC patients (p = 0.027), with the difference being statistically significant with p < 0.005. In summary, increasing wait time impacts HCC candidates less than non-HCC candidates and under increased competition for donor organs, HCC candidates' advantage increases.

Treatment issues in the care of patients with toxic epidermal necrolysis.

A review of current medical literature is presented to summarize treatment issues of ongoing controversy in the care of patients with toxic epidermal necrolysis. Terminology for the disease spectrum may be confusing and is discussed. Steroid treatment recommendations from the allergy and immunology literature are contrasted with burn center findings for optimal treatment. Issues of when to stop offending trigger medications, the value of a diagnostic biopsy, timing of hospitalization and the importance of prospective organ system monitoring are addressed.

Recognition, diagnosis, and management of heparin-induced thrombocytopenia and thrombosis.

This case report describes a post-coronary artery bypass graft patient who developed arterial thrombosis and loss of a dominant hand as a result of the common and serious immune complication of heparin anticoagulation, heparin-induced thrombocytopenia and thrombosis. This report underscores the need for all surgeons who use heparin in the course of their practice to be aware of heparin-induced thrombocytopenia and the spectrum of its clinical presentations and management. Thrombocytopenia or thrombosis that occurs in a patient receiving heparin should prompt a surgeon to stop all heparin as soon as possible and seek appropriate hematologic consultation. Because heparin-induced thrombocytopenia and heparin-induced thrombocytopenia and thrombosis are mainly clinical diagnoses, one should not wait for objective test confirmation of heparin-induced thrombocytopenia before stopping all heparin treatment. Alternative anticoagulation, other than low molecular weight heparin, must be considered for the patient who develops either condition. For surgeons who perform hand surgery, it is necessary to be aware of the significance of upper extremity thrombosis in a patient who is receiving heparin when consulted for surgical management.

Method for securing a subcuticular suture with minimal buried knot.

Subcuticular, intradermal suturing with retained suture has been performed with a variety of techniques requiring bulky buried knots. This report outlines a new method for closing a skin wound under light to moderate tension with fewer problems of buried knot bulkiness and gapping of the wound ends. The suture method was developed in a porcine model and has been used in clinical suturing with 3-0, 4-0, and 5-0 suture material. Outcomes for 23 cases have been satisfactory with no dehiscences and no exposure of knot material. This technique provides the surgeon with an excellent way to approximate skin wounds with a retained sucuticular suture. A modified technique for small 3- to 10-mm wounds is also described.

Paramedian sternal bone plate reinforcement and wiring for difficult sternotomy wounds.

Longitudinally oriented bone plates of stainless steel adapted to each sternal half after midline sternotomy provide a reinforced construct for transverse wiring. A method for placement of these 3.5-mm screw diameter plates in a supraperiosteal position is described. Clinical indications for use have included sternal osteoporosis, previous pull through of conventional wires, segmental sternal fractures, and obese body habitus. This technique is presented as a method to avoid sternal instability and potential wound infection for those patients at risk for sternal separation with standard wiring techniques.

Eccentric skin resection and purse-string closure for skin reduction with mastectomy for gynecomastia.

Skin redundancy following mastectomy for gynecomastia does not shrink and resolve in a predictable manner. Excess skin can be addressed best with resection at the time of the original operation if the scar can be minimized. Previously described techniques for resection of skin have shortcomings that include unacceptable scars, poor nipple positioning, and bulkiness of redundant, folded dermal tissue. The current technique for grade 2 and some grade 3 gynecomastias is performed with the creation of a 20-mm-diameter nipple-areolar complex based as a cephalad flap and designed eccentrically around the existing nipple. Eccentric skin resection in the vertical and horizontal planes is performed below the areolar flap. Wide access for completion of mastectomy is gained. The wound is then closed with a subcutaneous purse-string suture and inset of the areolar flap so that the scars are confined to the circumareolar area. This allows immediate skin recontouring with minimal skin scar. The patient does not have to endure prolonged anxiety while awaiting skin contracture, and this procedure eliminates the possible need for secondary surgery to resect redundant skin.