CEO Pay-for-Performance Heterogeneity Using Quantile Regression (CRI 2009-002)

We provide some examples of how quantile regression can be used to investigate heterogeneity in pay–firm size and pay-performance relationships for U.S. CEOs. For example, do conditionally (predicted) high-wage managers have a stronger relationship between pay and performance than conditionally low-wage managers? Our results using data over a decade show, for some standard specifications, there is considerable heterogeneity in the returns to firm performance across the conditional distribution of wages. Quantile regression adds substantially to our understanding of the pay-performance relationship. This heterogeneity is masked when using more standard empirical techniques

The optical field angle distortion calibration feasibility study for the Hubble Space Telescope fine guidance sensors

The results of an analytical study to investigate the feasibility of calibrating the Hubble Space Telescope's (HST's) fine guidance sensors (FGSs) within HST mission accuracy limits are presented. The study has two purposes: (1) to determine the mathematical feasibility of the optical field angle distortion (OFAD) calibration algorithm and (2) to confirm that the OFAD, plate scale, and FGS-to-FGS alignment calibration algorithms produced a calibration of the FGSs that satisfied mission requirements. The study concluded that the mathematical specification of the OFAD algorithm is adequate and permits a determination of the FGS calibration parameters (accurate to better than 0.003 arc-second) sufficient to meet the mission requirements. The algorithms implemented, the characteristics of the simulated data and procedures for data analysis, and the study's results are discussed. In addition, several useful techniques for improving the stability and accuracy of the OFAD solution are outlined

Preservation of lower extremity amputation length using muscle perforator free flaps.

Coverage of any lower extremity amputation stump must be durable to resist external forces, well contoured, and thin enough for proper shoewear or prothesis fitting. Preservation of bone length to maximise the ability to ambulate is also of paramount importance. If local soft tissues are inadequate to fulfil these prerequisites, consideration of a microsurgical tissue transfer is a reasonable option, especially to cover bone or save a major joint. Muscle perforator free flaps, as shown in this series of eight patients using four different donor sites, are a versatile alternative for the necessary soft tissue augmentation. Multiple choices are available and often even from the involved lower extremity to minimise further morbidity. The vascular pedicles of this genré of flaps are relatively exceedingly long and of respectable calibre to facilitate reaching an appropriate recipient site. They can be sensate if desired. Of course, muscle function is by definition preserved. Complications are minimal and usually related to the reason for the amputation in the first place

The integration of muscle perforator flaps into a community-based private practice.

Over the past decade, muscle perforator flaps have proven their versatility as another important option when a soft tissue flap is essential. Valuable as either local or free flaps, these are no longer a novelty, and are perhaps even becoming a necessity for the mainstream reconstructive surgeon. Prior microsurgical capabilities will unquestionably simplify the transition to harvesting the diminutive vascular pedicle of these flaps, while perhaps shortening the learning curve, but these skills are not imperative. With proper assistance and perseverance, as with any other aspect of surgery, muscle perforator flaps can become a mainstay, if not the preferred method, for soft tissue repairs even in the community hospital where resources tend to be less available

Sagittal split tibialis anterior muscle flap.

The potential use of the tibialis anterior muscle as a vascularized flap requires consideration of some function preservation technique because this is not an expendable muscle. A direct longitudinal vertical or partial sagittal split of this muscle will allow coverage of mid-tibial defects without impairing function. This is a valuable alternative for small defects, especially if the muscle is already exposed in the wound. The muscle must be malleable enough to allow stretching over the tibia, because otherwise posteromedial undermining (as used in the medial- hinged anterior turnover version) would be necessary to obtain the desired reach. This as a variation of the latter, if possible, not only is more expedient to implement but also better preserves the microcirculation of the muscle to ensure viability

The combined parascapular fasciocutaneous and latissimus dorsi muscle conjoined free flap.

BACKGROUND: A combined flap composed of at the least two otherwise distinct territories, each retaining its independent vascular pedicle yet joined together by a common interface, is by definition a conjoined flap. If the vascular pedicles are branches of a common source vessel, even more specifically this combination would be a branch-based [common] conjoined flap. METHODS: The parascapular fasciocutaneous and latissimus dorsi muscle flaps can be raised together as a clinical example of a branch-based (common) conjoined flap. This combination allows the creation of an extremely large cutaneous flap from the dorsal thorax while ensuring survival of both the muscle and skin portions in their entirety. RESULTS: A series of eight parascapular fasciocutaneous and latissimus dorsi muscle conjoined free flaps in eight patients had total flap survival of all components. Major complications, none of which were related to flap viability, eventually occurred in two patients; that is, one patient had a persistent chronic tibial osteomyelitis and the other had the covered lower limb amputated. CONCLUSIONS: The parascapular fasciocutaneous and latissimus dorsi muscle conjoined free flap is an extremely large, yet reliable flap. The anatomy is fairly consistent and already well known. In favorable situations, only a single recipient site is needed for the requisite arterial and venous microanastomoses. This combination can replace the need for multiple conventional flaps, yet violates but a single donor site. This series is the first clinical example of the branch-based (common) conjoined free flap

The proximal pedicled anterolateral thigh flap for lower limb coverage.

Although primarily considered as a versatile free-flap donor site, the anterolateral thigh can also be a source of a local muscle perforator flap. This attribute has previously been rarely considered for lower limb coverage. This small series of 3 additional cases demonstrates the usefulness of a proximal pedicled anterolateral thigh flap for medial and lateral thigh wounds. This flap can also be part of a combined flap, in particular when transferred with the vastus lateralis muscle as a local chimeric flap. The peninsular version of the anterolateral thigh local flap avoids venous congestion and is very reliable. The orthograde pedicled anterolateral thigh muscle perforator flap should be considered as another useful alternative for any upper thigh wound if a flap is essential

A brief history of minimally invasive plastic surgery.

It could be argued that a basic principle establishing plastic surgery as a distinct specialty always has been minimal invasive surgery. Although perhaps lagging behind the other surgical specialties specifically in adopting the surgical endoscope, this merely is a new tool to better achieve just that objective. Outcome enhancements initially predominated in aesthetic applications, but widespread use also in reconstructive endeavors has proved that there is indeed today a broad role for minimally invasive plastic surgery

Recognition of Potential Morbidity After Use of the Radial Artery as a Conduit for Coronary Artery Revascularization.

The use of the radial artery as an alternative vascular conduit for coronary bypass surgery has become increasingly popular. The plastic surgery experience with radial forearm flaps has shown that sacrifice of the radial artery is not always a benign maneuver. The potential morbidity after using this conduit donor site in terms of hand dysfunction or wound healing problems can be significant, and frequently must ultimately be addressed as part of the role of the reconstructive surgeon. Case examples of skin necrosis, subsequent forearm wound infection and hypertrophic scarring after radial artery harvest are presented to introduce this as a real concern and to allow a review of the entire spectrum of potential problems in this regard. Any selection process where the radial artery may be chosen as the coronary revascularization conduit must anticipate these known donor site complications