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Biomedical subjects

W P Adams

Publications and source records attributed to W P Adams.

35 records · Page 2Linked to original sources
PubMed1999

Sensory changes after traditional and ultrasound-assisted liposuction using computer-assisted analysis.

Postoperative sensory changes (i.e., hypesthesias) that occur after suction-assisted lipoplasty (SAL) are expected clinical sequelae. These disturbances usually return to normal within several weeks to months postoperatively. The presumed mechanism of injury is direct trauma to the peripheral nerves from the suction cannula. In addition, the potential for demyelination of peripheral nerves secondary to cavitation during ultrasound-assisted liposuction (UAL) is well known. Quantitative data describing hypesthesia after both procedures are limited. The purpose of this study was to objectively evaluate the severity and duration of postoperative hypesthesia after liposuction to better educate patients preoperatively. Furthermore, the authors use the three-stage UAL technique and wanted to determine whether a clinical difference in sensory return existed between suction- and ultrasound-treated areas. A total of 21 patients underwent liposuction performed by the senior author (RJ.R.). The abdomen, flanks, thighs, and medial knees were tested for objective sensation with the Pressure Specified Sensory Device preoperatively and at 2, 6, and 10 weeks postoperatively. A total of 102 sites were tested. On average, the SAL-treated areas improved to normal sensation by 6 weeks, whereas the UAL-treated areas took, on average, 10 weeks to recover. The severity of the hypesthesia was not correlated with larger aspiration volumes or longer UAL exposure time per site. At 10 weeks, 90 percent of UAL-treated patients and 89 percent of liposuction patients overall had recovered normal sensation. This study provides the body-contouring surgeon with good, objective data with which to educate patients regarding sensory return after liposuction.

Abdomen↗
PubMed1999

The aesthetic unit dorsal nasal flap: rationale for avoiding a glabellar incision.

The dorsal nasal flap was first introduced by Rieger in 1967. Since that time, it has proven reliable in the coverage of dorsal nasal soft-tissue defects; however, the glabellar component of the flap can leave a conspicuous scar and/or a contracture band. The authors present their experience with 48 patients who had an aesthetic unit dorsal nasal flap and their technique of incisional interface resurfacing, which obviates the need for the glabellar component. Objective independent assessment of the outcomes revealed overall excellent results, with no flap loss, hematoma, or dehiscence. Two cases of contour deformity were noted in male patients with preexisting rhinophyma in the area of the reconstruction. These design modifications enhance the aesthetic result and simplify the use of this flap in dorsal nasal reconstruction.

Adult↗
PubMed1999

Maxillary reconstruction: functional and aesthetic considerations.

Maxillary reconstruction is a challenging endeavor in functional and aesthetic restoration. Given its central location in the midface and its contributions to the key midfacial elements--the orbits, the zygomaticomaxillary complex, the nasal unit, and the stomatognathic complex--the maxilla functions as the keystone of the midface and unifies these elements into a functional and aesthetic unit. Maxillary defects are inherently complex because they generally involve more than one midfacial component. In addition, most maxillary defects are composite in nature, and they often require skin coverage, bony support, and mucosal lining for reconstruction. In the reconstruction of maxillary defects secondary to trauma, ablative tumor surgery, or congenital deformities, the following goals must be met: (1) obliteration of the defect; (2) restoration of essential functions of the midface, such as mastication and speech; (3) provision for adequate structural support to each of the midfacial units; and (4) aesthetic reconstruction of the external features. This review will discuss the pertinent anatomic considerations, the historical approaches to maxillary reconstruction, and the merits of the techniques in use today, with an emphasis on state-of-the-art reconstruction and dental rehabilitation of extensive maxillary defects.

Esthetics↗
PubMed1998

Lipid infiltration as a possible biologic cause of silicone gel breast implant aging.

The cause of silicone gel implant aging and rupture is not known. Recent reports indicate the failure rate is higher than previously published, and implant aging and rupture may be due to progressive mechanical deterioration of the outer vulcanized silicone shell. It is known that lipids are absorbed by the hydrophobic silicone elastomer, and lipid infiltration causes mechanical attenuation and possible failure of the elastomer. The purposes of this article are to analyze the silicone envelope/gel of explanted prostheses and the silicone elastomer of other medical grade silicone devices for lipid content and to suggest its possible role in implant aging and rupture. We assayed 33 ruptured silicone breast implant shells (mean age 13.1 years; range 8 to 26 years) and 8 medical grade silicone elastomer devices (mean age 3.7 years; range 3 months to 12 years) for evidence of lipid infiltration using thin layer chromatography. These were compared with control group assays from two nonimplanted silicone gel implants and one unused Silastic catheter. Ninety-eight percent of implants and other previously implanted silicone devices were found to have evidence of lipid infiltration compared with none in nonimplanted controls (p < 0.005). We conclude that lipids infiltrate the outer silicone shell and may be a factor related to breast implant aging and rupture due to progressive mechanical weakening of the outer silicone shell.

Breast Implantation↗
PubMed1998

Extending the role of liposuction in body contouring with ultrasound-assisted liposuction.

The initial experience with ultrasound-assisted liposuction in treating difficult fibrous areas, such as gynecomastia, hitherto not uniformly responsive to traditional suction-assisted lipoplasty, has led to the evolution and improvement of ultrasound-assisted liposuction techniques. This prospective study examined 114 consecutive patients treated with ultrasound-assisted liposuction over a 13-month period, from September of 1996 to September of 1997. The means by which this procedure helps achieve fat contouring differs from that of suction-assisted lipoplasty. Ultrasound-assisted liposuction removes fat through a fat emulsification process termed "cavitation," whereas suction-assisted lipoplasty achieves contouring through the mechanical avulsion of fat. The technique for the use of ultrasound-assisted liposuction has changed significantly from our initial series of patients to our current technique. To optimize the benefits of both ultrasound-assisted and traditional suction-assisted lipoplasty, we use a three-stage technique consisting of infiltration, ultrasound-assisted sculpturing, and suction-assisted lipoplasty for evacuation and final contouring. This has decreased our operative time, minimized complications, and optimized our body contouring results. Data were collected intraoperatively, including treatment times, treatment volumes, and treatment areas for both suction-assisted and ultrasound-assisted lipoplasty. A total of 114 patients were treated with ultrasound-assisted liposuction between September of 1996 and September of 1997. There were 23 male patients and 91 female patients. In general, the average total volume removed with this procedure decreased by about 50 percent throughout the series, whereas the suction-assisted lipoplasty volume increased correspondingly by 50 percent. Overall, suction-assisted lipoplasty volume was approximately two times ultrasound-assisted liposuction volume in the same area. Exceptions to this include the dense fibrous areas such as the back and male breast, where aspiration volumes were approximately equal. The total ultrasound-assisted liposuction treatment times were reduced after our initial 30 patients, and suction-assisted lipoplasty times increased. Total aspiration rates in our later patients averaged 36.2 cc/per minute for ultrasound-assisted and 58.4 cc/per minute for suction-assisted lipoplasty, whose rates were approximately 1.5 to 2 times faster than for ultrasound-assisted liposuction in most areas. After using this technology in our initial series of 30 patients, it became apparent that ultrasound was not a substitute for suction-assisted lipoplasty but rather a natural complement. We have found that the marriage of the techniques enhances results and minimizes complications, such as seromas, which have been reported to be 11.4 percent with ultrasound-assisted liposuction alone and are 2.6 percent in our series.

Abdomen↗
PubMed1998

The myoadipose flap: a new composite.

A prefabricated composite fat flap consisting of muscle woven into an anatomically distinct fat pad was studied in a rabbit model. In 17 rabbits, a 2-cm strip of latissimus dorsi was woven into the parascapular fat pad on one side, with the contralateral fat pad serving as a control. At 3 weeks, the endogenous blood supply of both the control and the experimental fat pads was isolated and ligated, and the composite fat/muscle flap was transferred to the chest wall. At 6 weeks, animals were killed, and flaps were analyzed for length, width, and weight; perfused with fluorescein or lead oxide; and examined histologically. Significant differences were found between the control and experimental fat pads with regard to weight and length. Experimental flaps were found to be perfused fully with fluorescein and lead oxide; control fat pads were found not to be perfused. The lead oxide group revealed extensive growth of blood vessels from the latissimus graft into the experimental fat pad. No vessels were visualized in the controls. Finally, sections of the control and experimental flaps were analyzed histologically. A preponderance of viable fat, with evidence of neovascularization, was found in experimental flaps, compared with the necrotic fat that characterized the controls. We conclude that prefabrication of a fat flap is possible and may have extensive application in various areas of plastic surgery.

Adipose Tissue↗
PubMed1998

Safety considerations and fluid resuscitation in liposuction: an analysis of 53 consecutive patients.

There is no agreement as to appropriate fluid resuscitation in patients undergoing liposuction. This has assumed greater significance, as surgeons have undertaken larger volume aspirations (> or = 4 liters) and the potential complications of hypovolemia and fluid overload have materialized. This prospective study of 53 consecutive healthy patients undergoing liposuction using a superwet technique served to develop general guidelines for safe perioperative fluid management, especially in regard to large-volume aspirations. In this context, "aspirate" is defined as the total fat and fluid that is removed during liposuction. All patients were monitored using standard noninvasive hemodynamic monitoring. Thirty-six patients were monitored perioperatively with Foley catheters. The 53 patients underwent liposuction alone. We did not include patients who underwent concurrent aesthetic surgical procedures because our intention was to establish fluid administration guidelines for the liposuction patient. There were no significant complications in our series. The intraoperative fluid ratio, defined as (intravenous fluid + infiltrate)/aspirate, was 2.1 for the small-volume group and 1.4 for the large-volume group. These values were significantly different (p < .001, t test). Average urine output in the operating room and recovery room and on the floor was satisfactory (> 0.5 to 1 cc/kg/hr) and did not relate to volume aspirated (p = 0.21, 0.91, and 0.6, respectively, t test). Four patients who underwent "large-volume" aspirations (> or = 4 liters) had transient hypotension, which was immediately responsive to crystalloid fluid boluses in the first postoperative hours. All other patients required only maintenance intravenous crystalloid postoperatively until oral intake had been resumed. There were no statistically significant differences in postoperative fluid administration between the small- and large-volume groups. Ninety-three percent of patients were discharged within 24 hours of surgery. Our suggested guidelines for fluid resuscitation based on this retrospective study are as follows: (1) small volume (< 4 liters aspirated): maintenance fluid + subcutaneous wetting solution; (2) large volume (> or = 4 liters aspirated): maintenance fluid + subcutaneous wetting solution + 0.25 cc of intravenous crystalloid per cc of aspirate removed after 4 liters. This formula has since been used in the care of 94 patients who have undergone liposuction exclusively. All patients have had unremarkable hospital courses. These guidelines do not replace sound clinical judgment. Good communication between the surgeon and anesthesiologist is critical to optimal patient care and safety.

Adolescent↗
PubMed1998

An analysis of silicone gel-filled breast implants: diagnosis and failure rates.

This retrospective review analyzed 180 women who underwent explantation of 357 silicone gel-filled breast implants from September of 1991 to January of 1995. Implant status, including shell integrity and implantation times, was determined at the time of explantation. The age range of the patients was 25 to 75 years, with a mean age of 47 years. The age of the implants ranged from 0.5 to 24 years, with a mean age of 10.5 years. Of the 292 implants with known and documented integrity status, there were 102 intact, 76 unruptured with signs of leakage, and 114 ruptured. The frequency of implant rupture significantly increased with implant age. The average age of rupture was 13.4 years. The average age of signs of leakage was 10.1 years. There were no significant differences in failure rates among the implant types of four manufacturers. Analysis of both mammography and magnetic resonance imaging (MRI) as diagnostic modalities for differentiating intact implants, implant leakage, and implant rupture was performed. Standard mammography was less reliable in diagnosing implant leakage or rupture (sensitivity, 55 percent; specificity, 69 percent) than MRI (sensitivity, 72 percent; specificity, 82 percent). In conclusion, implant rupture occurred at a significantly increasing rate with implant age (10 to 15 years). These findings were independent of implant type or manufacturer. Mammography alone is a below-average diagnostic tool for detecting leakage or rupture, whereas MRI is a more accurate modality.

Breast Implants↗
PubMed1997

The lateral nasal osteotomy in rhinoplasty: an anatomic endoscopic comparison of the external versus the internal approach.

A precise and reproducible lateral osteotomy is a requirement for successful rhinoplasty. Two basic techniques have evolved: the external perforated method and the internal continuous method. The literature supporting the external perforated technique maintains that it contributes to a controlled, stable fracture and produces less nasal airway narrowing, hemorrhage, edema, and ecchymosis; however, the continuous internal method is used by many rhinoplasty surgeons. Our study was designed to compare the two techniques in the fresh cadaver nose using a blinded endoscopic evaluation of the nasal mucosa after the osteotomies were performed by one of these two techniques. Nineteen fresh cadaver heads had an external perforated lateral osteotomy performed on one side and an internal continuous lateral osteotomy performed on the alternate side by an investigator with experience in the use of both osteotomies. In a blinded fashion, four different investigators used nasal endoscopy to detect mucosal perforations and bony irregularities. Eleven percent of the perforated osteotomies resulted in mucosal tearing as opposed to 74 percent of the continuous osteotomies (p < 0.001). This anatomic study confirms our clinical experience that the external perforated osteotomy results in a more controlled fracture with less intranasal trauma and can minimize the associated morbidity (hemorrhage, edema, and ecchymosis) in the rhinoplasty patient.

Adult↗
PubMed1994

Regulatory aspects of modifications to innovator bronchodilator metered dose inhalers and development of generic substitutes.

Regulatory requirements for modifications to an approved innovator metered dose inhaler (pressurized MDI; USP nomenclature: inhalation aerosol) and for development of a new generic product are discussed. Although many of the requirements apply generally to MDI's, they are discussed with specific reference to albuterol. Changes to the container and closure system may impact on the dosimetry of the redesigned product, as well as upon toxicologic and chemistry, manufacturing and controls (CMC) concerns. Changes to the formulation, including the use of alternate propellants, may raise issues requiring both clinical and in vivo performance evaluation. In view of the level of interest of a number of firms in approval requirements for generic Albuterol Inhalation Aerosol products, the article discusses in considerable detail the CMC and bioequivalence requirements for a generic product. Similarities in the CMC requirements for innovator and generic products are evident. Three comparative in vivo bioequivalence tests, particle size distribution, spray pattern and plume geometry, and unit spray content, established by the Division of Bioequivalence are discussed. Similarities and differences in the in vivo requirements for innovator and generic products are evident. Differences are the result of U.S. statute, which requires safety and efficacy testing for a product approved under a new drug application (NDA), but documentation of bioequivalence for a product approved under an abbreviated new drug application (ANDA). The advantages and disadvantages of three pharmacodynamic study designs which have potential usefulness for documentation of in vivo bioequivalence are discussed.

Bronchodilator Agents↗
PubMed1979

Salivary gland heterotopia in the lower part of the neck.

Heterotopic salivary gland tissue in branchial cleft cysts in the upper part of the neck reputedly differentiates from the epithelial lining of the cyst. We describe a patient with salivary gland tissue found in the lower part of the neck. How salivary gland tissue finds its way to the lower neck is obscure. It is conceivable that the tissue originated from a precervical sinus or cervical vesicle, a distinct embryologic structure that forms in the lower part of the neck between the second branchial arch and the upper thoracic wall, but that normally disappears by the time of birth. The epithelial lining of the cervical vesicle is thought to be associated with the early development of the glossopharyngeal and vagus nerves. Salivary gland tissue may differentiate from the epithelial lining of cervical vesicles and nurture the growing nerves by nerve growth factor elaboration.

Branchioma↗
PubMed1979

Conjugated estrogens bioinequivalence: comparison of four products in postmenopausal women.

The bioequivalence of four conjugated estrogens tablets USP was compared by measurement of seven estrogens or estrogen metabolites in the urine during steady-state dosing in postmenopausal women. Two studies compared three generic products with the innovator's product. The urinary excretion of 17 alpha-dihydroequilin, 17 alpha-dihydroequilenin, and 17 alpha-estradiol were significantly greater in all cases with the innovator's product than with the generic products. Statistically significant differences between products were observed occasionally for other components. The generic products thus were bioinequivalent to the innovator's product, although all products essentially met current compendial specifications. A third study observed no significant differences between three batches of the innovator's product for the seven components. Total conjugated estrogens excretion of all products at the steady state was essentially equal and correlated with neither disintegration time nor dissolution half-time. Bioinequivalence between products is discussed in relation to the need for an improved USP conjugated estrogens monograph. Evidence suggesting the metabolism of a fraction of dosed estrone, equilin, and 17 alpha-dihydroequilin to 17 beta-estradiol, 17 beta-dihydorequilim, and 17 alpha-dihydroequilenin, respectively, is presented.

Biological Availability↗
PubMed1978

Steady-state urinary excretion method for determining bioequivalence of conjugated estrogen products.

The steady-state excretion of conjugated estrogens in the urine of postmenopausal women dosed with conjugated estrogens tablets was studied using a modification of a previously published method. The procedure was used to quantitate the estrogens both before and during conjugated estrogens replacement therapy. The method, which is relatively specific, involves enzyme hydrolysis of urine samples a number of classical extraction and purification steps, and analysis of the silylated estrogens on a 2.7-m, 1.7% diethylene glycol succinate column using flame-ionization detection. The results indicate that steady-state urinary estrogen excretion levels were obtained within 17 days of dosing. Furthermore, the urinary estrogen excretion profile was significantly different from the composition of the estrogens in the dosage form.

Adult↗