Extremal Contours Research Articles

Brachioplasty After Massive Weight Loss: A Simple Algorithm for Surgical Planning

Since 1954, when brachioplasty was first addressed in the literature [1], several different techniques have been described [2 8]. With the current trends in bariatric surgery, the subject has reemerged, and modifications to the techniques and accessory therapies, such as liposuction, have evolved. Doctor Cannistra and his team present an alternative approach to the management of upper extremity contour deformities. In the literature, Aly describes a similar technique, with comparable reference points, incision site, and configuration [4]. Nevertheless, this article focuses on providing a standard way of delineating landmarks for preoperative marking, thus facilitating this task, especially for the inexperienced surgeon. This method aims to reduce the risk of overcorrection, decrease complications, and conceal the scar. The described procedure is for cases of massive weight loss in which skin ptosis attributable to tissue lipodystrophy is the main component of the problem, and minimal excess lipomatous tissue exists, or has been previously liposuctioned. Using this technique, the marking follows a standardized pattern, avoiding asymmetry. It is a simple and straightforward demarcation, with clear reference points, creating a final straight closure line. This type of closure has been questioned in the past due to the contractile tendency of the scar, and some authors prefer sinusoidal incisions [5]. At the level of the axilla, a Z-plasty is advised. In our experience, the Z-plasty gives good results by addressing contraction, shaping of the area, and reducing axillary ptosis. An early preoperative liposuction is used, providing assessment of skin retraction capacity and selecting the patients with true indications for surgery while minimizing the dissection and skin resection. The liposuction approach and technique are not described, but would be of interest for clarification. We agree with early staged liposuction to reduce the risk of dehiscence and to enhance the final cosmetic result. Another point for remark is the scar location because this is a strongly debated point. In this case, the authors prefer to place the suture line posterior to the medial bicipital groove to hide the scar on the frontal view. Other surgeons prefer to place it in the bicipital groove. In the picture submitted with the article, the patient s scar and part of the Z-plasty are visible. This particular point should be thoroughly discussed preoperatively with the patient, and it is our opinion that the patient should be the one to decide the location of the scar because both locations have drawbacks. Brachioplasty scars can be wide, raised, and visible in short-sleeved clothing regardless of location. The authors present a good number of patients (n = 50) over 6 years of experience. Unfortunately, only one of the patients preand postoperative results were included. We agree that the described technique is a simple way to approach a brachioplasty after massive weight loss. The results are acceptable, as is the complication rate.

A New Technique for Correction of Congenital Constriction Rings

Congenital constriction ring (CCR) is among the most common congenital anomaly of the extremities. However, few techniques have been described for correction of this anomaly, and none of these techniques could provide a complete elimination of the deformity. Therefore, new surgical techniques are needed for correction of this challenging deformity. Here, a new technique, namely, Mutaf procedure, for the correction of congenital constriction rings is described. In this technique, following excision of the fibrotic constriction ring, the groove is filled with the turnover dermofat flaps elevated from both sides of the ring in an alternating pattern. Then skin closure is done with rectangular-plasty technique. Over 8 years, this new technique was used for correction of severe CCRs of the lower extremities in 7 patients aged 1-7 years. In all patients, a normal extremity contour was obtained, with complete elimination of the sandglass deformity caused by the constriction ring. A mean follow-up of 3 years revealed a normal growth of the operated extremity in all patients. The scars were found to be esthetically acceptable. No further surgery was required. Filling the circular groove caused by the constriction ring with dermofat flaps, this new technique eliminates the soft tissue deficiency and provides a normal extremity contour. Moreover, since rectangular-plasty allows replacing the major limbs of the incisional scars within the relaxed skin tension lines, it provides a better scar in comparison with old Z-plasty techniques.

Application of response surfaces for reliability analysis of marine structures

Marine structures subjected to multiple environmental loads (i.e. waves, current, wind) are considered. These loads are characterized by a set of corresponding parameters. The structural fatigue damage and long-term response are expressed in terms of these environmental parameters based on application of polynomial response surfaces. For both types of analysis, an integration across the range of variation for all the environmental parameters is required. The location of the intervals which give rise to the dominant contribution for these integrals depends on the relative magnitude of the coefficients defining the polynomials. The required degree of numerical subdivision in order to obtain accurate results is also of interest. These issues are studied on a non-dimensional form. The loss of accuracy which results when applying response surfaces of too low order is also investigated. Response surfaces with cut-off limits at specific lower-bound values for the environmental parameters are further investigated. Having obtained general expressions on non-dimensional form, examples which correspond to specific response quantities for marine structures are considered. Typical values for the polynomial coefficients, and for the statistical distributions representing the environmental parameters, are applied. Convergence studies are subsequently performed for the particular example response quantities in order to make comparison with the general formulation. For the extreme response, the application of ‘extreme contours’ obtained from the statistical distributions of the environmental parameters is explored.

A Technique of Brachioplasty

Various techniques for the management of upper extremity contour deformities have been suggested since aesthetic brachioplasty was first described. Such deformities are commonplace with aging, after normal weight loss, and especially after massive weight loss such as is seen following bariatric surgery. Despite the multiplicity of procedures described for the correction of these deformities, there are still problems associated with current brachioplasty techniques, including incorrectly placed incisions, widened hypertrophic scars, and postoperative contour deformities. In addition, postoperative skin laxity and ptosis in the axillary region are frequently encountered in the more extreme deformities. The authors present their technique for upper extremity brachioplasty. This technique is suitable for patients with severe brachial ptosis and skin laxity, with relatively little lipomatous tissue, which may extend from the olecranon to the chest wall. The described surgical approach provides excellent overall extremity contour with favorable scars while simultaneously addressing axillary contour deformities.

Surface Reconstruction from Multiple Views of Painted Curves

A normal to the extremal contour of a 3D object is the same as the normal computed for the image contour projected on the unit sphere by the rays grazing the extremal contour. This fact is utilized in the present work to derive the parameters of quadric surfaces. We require three views of the point of intersection of two painted curves on an object. Out of the three views, one view must be chosen such that the image contours of the curves appear close to the extremal contours. Then the normals to the image contours (i.e., apparent contours) and the normals to the surface curves (i.e., contour generators) can be related through differential geometry to yield quadric representation of a surface at the point of interest.

Staged skin and subcutaneous excision for lymphedema: a favorable report of long-term results.

Numerous surgical procedures have been proposed for the management of lymphedema. The postoperative results vary, and unfortunately none of the procedures are curative. As a result, some degree of recurrence of leg edema is seen in all patients postoperatively. Reported here is a long-term follow-up of patients with lower extremity lymphedema managed by skin and subcutaneous tissue excision. Thirty-eight patients (6 male; 32 female) with lower extremity lymphedema have been followed up for an average of 14 (3 to 27) years after staged subcutaneous excisions performed beneath skin flaps. Seven patients had been treated previously by other procedures. Of the 38 lymphedema patients, 10 patients developed edema after pelvic or groin ablative surgery, radiation therapy, or both. Results were documented by various methods: physical examination, circumferential measurements, volume displacement, serial photography, lymphoscintigraphy, and patient survey. Of these, it is believed that photographs are the easiest and as representative as any other method, all of which have great variability. Of the 38 patients, 30 patients had significant and long-lasting reduction in extremity size associated with improved function and extremity contour. Episodes of recurrent cellulitis were reduced or completely eliminated. No differences in the long-term results were seen in patients with acquired as opposed to congenital lymphedema. Men did not have as much improvement as women. Two patients had no change in leg swelling, and six patients (three men) had progressive swelling after surgery. Partial wound separation occurred immediately postoperatively in one patient, and three patients had loss (less than 2 cm) of the skin flap, all in the ankle region. None of these instances required further surgery, and no other significant complications were encountered. Staged skin and subcutaneous excision beneath skin flaps appears to provide long-lasting improvement for lower extremity lymphedema, regardless of cause, in the majority of patients treated.

Robust Shape Recovery from Occluding Contours Using a Linear Smoother

Recovering the shape of an object from two views fails at occluding contours of smooth objects because the extremal contours are view dependent. For three or more views, shape recovery is possible,...

Acoustical Consequences of Lip, Tongue, Jaw, and Larynx Movement

In the past, numerous attempts have been made to develop quantitative models of the human vocal tract. The present paper describes such a model and some of its acoustic properties. It has been constructed with a view towards finding a set of parameters that are physiologically “natural.” Thus it differs from earlier schemes in that the mandible has been incorporated as an independent parameter. Other novel features can be interpreted to represent larynx height, the rounding-spreading action of the lip musculature, and “genioglossal,” “styloglossal,” and “hyoglossal” components of tongue shape. The paper describes the acoustic effects of varying these parameters systematically. The model is capable of generating most of the vowel qualities known to occur in the languages of the world. In general, well-known vowel sounds are found along the extreme contours of the total acoustic space characteristic of the model. They are not necessarily located at acoustic “plateaus” or regions insensitive to articulatory imprecision. The model specifies the notion of “possible vowel articulation” in terms of parameters that are not in a one-one relation with distinctive feature dimensions such as open, close, high, low. A discussion of the implications of these results for universal phonetic and phonological theory concludes the paper. [This work was supported by a research grant from The National Institutes of Health.]

Extremal nozzle contours for gas flows with particle lag

The determination of the extremal nozzle contour for gas flow without foreign particles has been carried out in several studies [1–6], based on the calculation of the flow field using the method of characteristics.