Biomedical subjects

W W Shaw

Publications and source records attributed to W W Shaw.

At least 19 recordsLinked to original sources

PubMed1998

Superior gluteal free flap breast reconstruction.

The authors substantial experience with the superior gluteal free flap for breast reconstruction indicates that this is a more difficult but important free flap for breast reconstruction. Compared with the standard transverse rectus abdominis myocutaneous (TRAM) free flap, it is a much less forgiving operation with many specific technical details. With careful attention to details on flap design, recipient vessel selection anastomsis, and flap insetting, the success rate and morbidity of the gluteal flap operation are highly acceptable. For patients unsuitable for the TRAM flap for autologous tissue reconstruction, this is a very valuable alternative. It can achieve some spectacular results in breast reconstruction in terms of volume, replacement, and projection--even in very thin patients.

Buttocks↗

PubMed1997

Circumferential wrapping of a flap around a scarred peripheral nerve for salvage of end-stage traction neuritis.

Nine patients with chronic severe pain due to end-stage traction neuritis of an intact peripheral nerve underwent external neurolysis and epineurectomy or epineurectomy and internal neurolysis followed by circumferential wrapping of the involved segment of nerve with a pedicle flap or free flap consisting of either subcutaneous fat tissue, fascia, or muscle. Seven patients (77%) followed for between 1 and 5 years had substantial relief of pain. Two patients (22%) had no decrease in their pain at all. Circumferential wrapping may cushion the nerve from external pressure on the overlying skin, may isolate the nerve from the traction forces of adjacent moving tendons to allow improved gliding of the nerve, and may promote revascularization of a scarred nerve. This surgery may be indicated for patients with persistent pain following multiple carpal tunnel or cubital tunnel surgeries.

Adult↗

PubMed1997

Simultaneous bilateral breast reconstruction with the transverse rectus abdominus musculocutaneous free flap.

OBJECTIVE: The purpose of the study was to assess the results and morbidity associated with simultaneous bilateral TRAM free flap breast reconstruction and describe refinements in its surgical technique. SUMMARY BACKGROUND DATA: Bilateral prophylactic total mastectomies might be an agreeable option for those patients at highest risk for breast cancer if autogenous tissue breast reconstruction could be performed with reasonable technical ease and acceptable morbidity. However, some surgeons harbor reservations regarding the extensiveness of the surgery, the associated morbidity, and the aesthetic quality of the resulting outcome. METHODS: A multicenter retrospective review of clinical experience with 120 consecutive patients who underwent 240 simultaneous bilateral TRAM free flap breast reconstructions was developed. RESULTS: The average operating time, including the time required for the breast ablative portion of the procedures, was 8.6 hours. The average length of hospitalization was 7.6 days. However, for the last 40 patients, these figures were reduced to 7.1 hours and 6.1 days, respectively. Nonautologous blood transfusions were needed in 33 cases (28%), but only 1 was required in the last 40 patients. Thromboses developed in six of 240 flaps (2.5%): 4 were arterial and 2 were venous. Re-exploration allowed us to restore circulation in five flaps, whereas one flap was unsalvageable and was replaced successfully with an alternate flap. An uncomplicated deep vein thromboses developed in one patient with a history of recurrent deep vein thromboses that had no adverse effect on her outcome. Minor complications developed in 18 patients (15%) (e.g., hematoma, partial wound necrosis, wound infection, or prolonged postoperative ileus) that did not affect the long-term outcome. Fourteen patients (11.6%) had abdominal wall weakness or hernias. Follow-up time averaged 37.2 months (range, 14-62 months). On last follow-up, patients' self-reported overall satisfaction with the procedure was 56% excellent, 40% good, and 4% fair. CONCLUSIONS: Simultaneous bilateral free flap reconstruction is technically feasible with a high rate of success and an acceptable morbidity. When performed by experienced surgeons, bilateral prophylactic total mastectomies combined with simultaneous bilateral TRAM free flap reconstruction may provide an adequate surgical option with aesthetically acceptable results for patients at high risk for breast cancer.

Blood Loss, Surgical↗

PubMed1997

Durability of prefabricated versus normal random flaps against a bacterial challenge.

UNLABELLED: Numerous reports of flap prefabrication have demonstrated good survival. The durability of these flaps compared with that of other flap types or normal tissue, however, remains unknown. The purpose of this study was to determine how prefabricated flaps respond to a bacterial challenge compared with identically sized normal random-pattern flaps. Rat abdominal cutaneous-panniculus carnosus flaps were prefabricated with a standard-sized groin fasciovascular tissue carrier and then inoculated with Staphylococcus aureus. The prefabricated flaps were divided into two groups. Group one (standard prefabricated flap, n = 24) received no growth factor. Group two (n = 24) received an angiogenic growth factor between the carrier and flap tissue. A random-pattern flap served as a nonprefabricated control (n = 12). Grading of the prefabricated flaps with growth factor versus the standard prefabricated flaps versus controls showed dehiscence (41 versus 37 versus 4 percent), ulceration (21 versus 29 versus 18 percent), erythema/cellulitis (40 versus 44 versus 8 percent), and necrosis (9 versus 29 versus 0 percent). The control flaps had significantly less dehiscence, erythema/ cellulitis, and necrosis than the standard prefabricated flaps. Similarly, the prefabricated flaps with angiogenic growth factor had significantly less necrosis than the standard prefabricated flaps. CONCLUSIONS: (1) prefabricated flaps were demonstrated to be less durable than random-pattern flaps against a bacterial challenge, (2) angiogenic growth factor may help to improve the durability of prefabricated flaps against bacterial infection, and (3) the biologic behavior of prefabricated flaps is not the same as that of normal tissue and deserves further investigation.

Animals↗

PubMed1997

The spontaneous return of sensibility in breasts reconstructed with autologous tissues.

Some spontaneous return of sensibility following autologous tissue breast reconstruction is often suspected but not well documented. In the present study, objective touch-pressure, pain, temperature, and vibratory sensibilities were recorded in 33 autologous breast reconstructions at an average of 25.2 months postoperatively. Correlation of the sensory return with patients' satisfaction toward reconstruction was done by a detailed questionnaire. All except one patient regained a variety of sensibilities touch pressure in 97 percent of patients (averaging 81.05 gm/mm2 versus control of 7.98 gm/mm2), pain in 88 percent of patients, heat in 64 percent of patients (45 percent of quadrants), cold in 82 percent of patients (67 percent of quadrants), and high- and low-frequency vibration in 100 percent of patients (high in 90 percent of quadrants, low in 96 percent). Subjectively, 94 percent considered their chest comfortable to touch following reconstruction compared with 34 percent following mastectomy. On a scale from 1 to 10, patients rated their reconstructions an average of 9.3. Our findings confirm the spontaneous return of sensibility following a variety of autologous tissue breast reconstructions. The value of the sensory return is suggested by the high degree of satisfaction in nearly all patients. Further attempts to correlate the degree of sensory return with the degree of satisfaction were inconclusive because of the uniformly high satisfaction reported by the patients. The mechanism of reinnervation appears to come both from the skin margins and from the deep surface of the flap. Future developments in breast reconstruction should take into consideration the eventual quality of sensory return.

Adult↗

PubMed1997

TRAM flaps in patients with abdominal scars.

Of 114 patients who had TRAM flap breast reconstruction, 46 (40 percent) had preexisting abdominal surgical scars. Sixty-six free TRAM flaps and 9 pedicled TRAM flaps were performed in the 46 patients. The records were analyzed to determine what impact, if any, abdominal scars had on postoperative complications. There were no reconstructive failures or significant (>25 percent) flap losses. Eight minor complications occurred in 7 patients (15 percent). The incidences of abdominal-wall weakness (4.3 percent), partial flap loss (4.3 percent), minor fat necrosis (4.3 percent), and donor-site wound problems (4.3 percent) were acceptable. Subcostal scars and multiple abdominal scars were found to predispose to skin complications. Right lower paramedian scars precluded free TRAM flaps because of damage to the inferior epigastric vessels in three of three patients. Both obesity (p = 0.003) and smoking (p = 0.05) were associated with a greater risk of wound-healing complications. We conclude that with certain technical modifications, TRAM flap reconstruction is a safe and effective procedure in patients with abdominal scars.

Cicatrix↗

PubMed1996

Prefabrication of a neo-endocrine organ: a rat model.

Previous work in the field of flap prefabrication has demonstrated that many tissues, including skin, bone, cartilage, muscle, and composite tissue, can be neovascularized with a carrier flap and transplanted to a distant site using microvascular technique. We have recently shown in a rat model that islets of Langerhans survive in large numbers when transplanted into a groin-based fasciovascular pedicled (FVP) flap. In the current study, we examined whether sufficient islet tissue can be transferred using microvascular free transfer of islet-containing flaps to reverse experimental diabetes. In the first phase of the experiment, islets from two Lewis rat donors were transplanted into the FVP flap of an isogeneic diabetic animal. Within 5 days, reversal of diabetes was noted in 4/4 experimental animals and in 0/4 control animals. In the second phase of the experiment, islet-FVP flaps were created in nondiabetic "carrier" animals. After 2 weeks the islet-containing flaps were harvested and transplanted to recipient diabetic Lewis rats using microvascular free transfer technique. Reversal of diabetes was noted within 10 days of free-flap transplant, and the diabetic state returned following removal of the flaps. Although preliminary, these results demonstrate that fasciovascular flaps can act as vehicles for the creation and transplantation of a functional neo-endocrine pancreas.

Animals↗

PubMed1996

The revascularization interface in flap prefabrication: a quantitative and morphologic study of the relationship between carrier size and surviving area.

To make a quantitative assessment of the relationship between size of vascular carrier and surviving area in a prefabricated flap, vascular carriers composed of the superficial epigastric arteriovenous bundles and a surrounding fascial patch with varying sizes were transferred under a 7- x 7-cm bipedicled abdominal skin flap in a rat model. Seven days later, the abdominal flaps were raised as composite island flaps connected only by the superficial epigastric vascular pedicle, transferred, and then sutured back into place. Immediately after replacement, the degree of revascularization was assessed using quantitative skin fluorometry, after intravenous injection of sodium fluorescein. At 7 days after elevation as an island flap, the area of skin flap surviving was recorded and plotted on a map depicting the original flap surface. High levels of fluorescence appeared on the flap surface where the carrier was tacked underneath. The prefabricated island flaps survived with a circular shape up to approximately 4 times the radius of the vascular carrier. When the distance was converted into area, theoretically, an area 13 times the area of the vascular carrier survived, regardless of its size in this experimental model. Histologic examination revealed connections of fine capillaries between the carrier and flap.

Animals↗

PubMed1996

Safe ischemia time in free-flap surgery: a clinical study of contact-surface cooling.

Although the effectiveness of cooling in extending tolerable ischemia time is well-established experimentally, most free-flap surgeons are still concerned about this problem and try to limit the ischemic period to less than 1 hr. Clinically, contact-surface cooling has been used empirically to prolong the limits of ischemia time; however, its applications are unproven. It also remains unknown whether contact-surface cooling has detrimental effects on flap tissue, such as vessel spasm leading to thrombosis. The purpose of this study was to determine, in a clinical setting, if skin, muscle, and bone free flaps of considerable size could tolerate prolonged cold ischemia without adverse effects. Flap size, cold ischemia time, and surgical outcomes were studied in 189 consecutive free flaps. Microvascular thrombosis occurred in 5/378 (1.3 percent) of anastomoses. The overall flap complication/flap loss rate was 7/189 (3.7 percent). Mean ischemia time for all flaps was 2 hr and 6 min (range: 30 min to 5 hr, with one case at 6 hr and 8 min). The mean ischemia time for cases with flap complications was 2 hr 20 min, while ischemia time for cases with thrombosis averaged 2 hr 13 min. The one flap loss had an ischemia time of 1 hr 35 min. No statistically significant correlations existed between duration of ischemia time or duration of contact-surface cooling and the incidence of thrombosis, flap complication, or flap failure. Among the conclusions were that, within a 4-hr period of cold ischemia, the application of the surface-cooling technique is not detrimental to free flap surgery; thus, concern for ischemia, and especially the "no reflow" phenomenon, generally should not interfere with efficient and orderly free-flap surgery.

Humans↗

PubMed1996

Salvage of a below-the-knee amputation with a fillet of foot free flap: a 15-year follow-up.

In the setting of traumatic injury, obtaining suitable coverage to salvage a below-the-knee amputation has been performed by using a variety of tissue flaps, including the fillet of foot free flap. This flap is a free tissue transfer that utilizes the soft tissues of the foot for stump coverage. In this report, we present a 15-year follow-up of a patient with a fillet of foot free flap to demonstrate its applicability and long-term efficacy. We also discuss technical aspects for performing this procedure. In this follow-up, we have found the flap to be extremely durable, even when placed in the weight-bearing position of the stump, and also lacking many of the usual complications associated with the weight-bearing portion (e.g., blisters, ulcerations). We conclude that the fillet of foot free flap is an excellent salvage flap for providing long-term length, coverage, and durability in an amputated, weight-bearing extremity.

Accidents, Traffic↗

PubMed1996

Capsular synovial metaplasia as a common response to both textured and smooth implants.

Recent reports suggested that the presence of synovial metaplasia in the capsular tissues of breast implants is greater with textured-shelled implants compared with smooth. Textured implants, however, have become popular only in the last few years. Therefore, the studies do not address the possibility that synovial metaplasia may be a dynamic process related to time (e.g., implant age) rather than implant shell surface. In the current study, 159 implant capsules (85 patients) removed between February of 1992 and July of 1993 at UCLA Medical Center were evaluated histologically and correlated with clinical data, including the age of implants. Synovial metaplasia was identified in 40 percent (64 of 159) of the capsule specimens. A logistic regression analysis that removed the effect of implant age demonstrated no correlation of implant shell type (textured versus smooth) with the presence of synovial metaplasia. Gel bleed, implant location, pericapsular fluid, implant rupture, and capsular contracture also did not have any significant association with synovial metaplasia in the current study. The incidence of synovial metaplasia appears to decrease with age (77 percent at < 5 years; 22 percent at > 15 years). Our findings suggest that synovial metaplasia is not rare and in fact may be a fairly common transitional histologic finding. It may be part of the common progression that occurs at the implant-capsule interface. The clinical significance remains unknown.

Adult↗

PubMed1996

Microbial evaluation: 139 implants removed from symptomatic patients.

Possible adverse effects of microbial organisms have been implicated in symptomatic silicone implant patients. In the literature, numerous authors have investigated the possible role of infection with respect to implant problems. To date, various bacterial species have been reported, including Staphylococcus aureus, Staphylococcus epidermidis, peptostreptococci, and Clostridium perfringens. Infections in polyurethane-coated prostheses also have been shown to prolong morbidity. Antibiotic use has been relatively empirical in this regard. The purpose of this study was, first, to determine the frequency, type, and clinical relevance of microbial colonization on implant surfaces removed from symptomatic patients and, second, to determine possible effects of microbial colonization on implant integrity (gel bleed, rupture). A total of 139 implants from 72 symptomatic patients were entered into the prospective clinical study between February of 1993 and July of 1994 at the UCLA Medical Center. The implant shell types included smooth (79 percent), polyurethane (8 percent), textured (7 percent), and smooth and Dacron (6 percent). The implant locations were subglandular (71 percent), submuscular (28 percent), and subcutaneous (1 percent). Of the 139 implants removed, 69 percent were intact and 31 percent were ruptured. Forty-seven percent of 139 implants were culture-positive. Propionibacterium acnes was isolated most frequently (57.5 percent), followed by Staphylococcus epidermidis (41 percent), and then Escherichia coli (1.5 percent). No fungal infections were identified. Culture positivity was not significantly associated with systemic symptoms. Sixty-seven percent of the positive culture implants were intact; 33 percent were ruptured. The frequency (47 percent) and types (P. acnes and S. epidermidis) of microbial colonization are determined in symptomatic silicone implant patients.

Adult↗

PubMed1996

Flap prefabrication: effectiveness of different vascular carriers.

A new experimental model of a vascular carrier to prefabricate a "secondary" island flap, the popliteal musculovascular pedicle, was developed in the rat. Using quantitative skin-surface fluorometry 30 minutes after sodium fluorescein injection and a flap survival area in the prefabricated 8 x 2.5-cm abdominal composite island flap, we compared the revascularization ability of our muscular carrier to nonrevascularized controls: the skeletonized arteriovenous pedicle and the fasciovascular pedicle. The free composite graft with no vascular carrier exhibited near-total necrosis. The skeletonized vascular pedicle demonstrated 15.2% +/- 7.8% perfusion of normal skin on dye fluorescence index measurements and 50% flap survival. The fasciovascular pedicle exhibited better revascularization, with a dye fluorescence index of 36.2 +/- 15.5 (p < 0.01) and 90% +/- 10% flap survival (p < 0.001). India ink injection study and histological examination of our model provided visual evidence of revascularization from the musculovascular pedicle, along with preservation of the carrier's muscular architecture. The musculovascular pedicle is a reliable carrier for making new, vascularized composite flaps.

Abdomen↗

PubMed1995

Clinical experience with a microvascular anastomotic device in head and neck reconstruction.

BACKGROUND: Despite numerous refinements in microsurgical technique and instrumentation, the microvascular anastomosis remains one of the most technically sensitive aspects of free-tissue transfer reconstructions. MATERIALS AND METHODS: Concurrent with the development of microsurgical techniques, various anastomotic coupling systems have been introduced in an effort to facilitate the performance and reliability of microvascular anastomoses. The microvascular anastomotic coupling device (MACD) studied here is a high-density, polyethylene ring-stainless steel pin system that has been found to be highly effective in laboratory animal studies. Despite its availability for human clinical use over the last 5 years, reported clinical series remain rare. Our clinical experience with this MACD in 29 head and neck free-tissue transfers is reported herein. RESULTS: Thirty-five of 37 (95%) attempted anastomoses were completed with 100% flap survival with a variety of donor flaps, recipient vessels, and clinical contexts. Two anastomoses were converted to conventional suture technique intraoperatively, and one late postoperative venous thrombosis occurred after fistulization and vessel exposure. CONCLUSIONS: We conclude that the MACD studied here is best suited for the end-to-end anastomosis of soft, pliable, minimally discrepant vessels. Previous radiation therapy does not appear to be a contraindication to its use. Interpositional vein grafts may also be well suited to anastomosis with the device. When carefully and selectively employed by experienced microvascular surgeons, this MACD can be a safe, fast, and reliable adjunct in head and neck free-tissue transfer reconstructions, greatly facilitating the efficiency and ease of application of these techniques.

Adult↗

PubMed1995

Is surface cooling effective for tissue preservation in free-flap surgery?

Effective tissue cooling can extend the period of safe ischemia. To determine whether the technique of surface cooling could produce an effectively low core temperature (4 degrees to 10 degrees C) in the flap core in a reasonable amount of time, bovine muscle/subcutaneous fat flaps, weighing 400, 800, and 2000 g, were brought to 37 degrees C and then surface cooled. Temperatures were then recorded every 5 min. All flaps were able to attain 4 degrees C in the core; the average times for the 400, 800, and 2000 g flaps to reach 4 degrees C were 136, 153, and 194 min, respectively. Although a clear inverse relationship existed between flap weight and effectiveness of core cooling, even relatively large flaps (2000 g) could still achieve sufficiently low core temperatures from surface cooling well within tolerable warm ischemia time. Concern for ischemia time generally should not interfere with efficient, orderly, free-flap surgery.

Animals↗

PubMed1995

Clinical significance of intracapsular fluid in patients' breast implants.

Clinical reports on the incidence and clinical significance of intracapsular fluid are lacking in the literature. It remains unknown whether the presence of intracapsular fluid has any relation to implant infection or colonization. The purpose of this study was to determine the frequency and type of intracapsular fluid, specifically, whether intracapsular fluid causes implant infection, implant rupture, or bacterial colonization. A total of 139 implants from 72 symptomatic patients were entered into the prospective clinical study. Our study demonstrated the presence of intracapsular fluid in 21 of 139 (15%) implants. Positive microbial cultures were identified in 39% of the implants in the positive intracapsular fluid group, compared to 43% in the negative fluid group. There was no statistically significant difference between these groups. Also, no adverse clinical relationship was demonstrated between local symptoms and presence of intracapsular fluid. There was, however, a positive trend toward the presence of fluid when implant shell types were nonsmooth (polyurethane and textured silicone implants). Further studies are indicated to elucidate the fluid production mechanism and possible secretory activity of prosthetic capsules interfacing the textured breast implant surface.

Adult↗

PubMed1995

Evaluation of autogenous tissue breast reconstruction using MRI.

Recent controversy encountered with silicone breast implants has increased the use of autogenous tissue for breast reconstruction following mastectomy. Surveillance of patients who have undergone autogenous tissue reconstruction is important in the evaluation of recurrent or new cancer. Magnetic resonance imaging (MRI) has proven to be a useful technique in the delineation of soft tissues and provides excellent resolution. Recently, MRI has been reported to be a valuable diagnostic imaging modality for the evaluation of augmented breast implant patients with regard to implant rupture detection, silicone granuloma identification, and silicone gel migration delineation. In this study, various autologous tissue donor sites currently available for breast reconstruction were imaged by MRI. The following donor flaps were included: fleur-de-lis, TRAM, gluteal, and tensor fasciae latae. A total of 10 clinical cases were investigated. The anatomic basis of each flap type is illustrated, and various tissue components of flap tissue (skin, fat, and muscle) are demonstrated on MRI scan. Anatomic knowledge of autogenous tissue types and MRI appearance of the flap-breast-chest-wall interface are critical in the surveillance and follow-up of breast cancer patients.

Breast↗

PubMed1994

In vivo anatomic study of cutaneous perforators in free flaps using magnetic resonance imaging.

Adequate knowledge of perforator location preoperatively will enable the surgeon to achieve optimal flap design and flap survival. Most previous attempts have relied on the use of Doppler ultrasound and earlier anatomic knowledge. With ultrasound, there may at times be signals from overlapping blood vessels. Magnetic resonance imaging (MRI) is sensitive to flowing blood and, on an MRI scan, dark-flow void characterization is used to identify perforators. This study was undertaken to evaluate the anatomic location and the number of perforators in the flap zone, based on inherent blood flow, and to determine information about the dominant perforators for free-flap design, using MRI. The CSMEMP technique allowed the characterization of flow void signals, which appeared in the image as dark spots. This technique also enabled differentiation of the surrounding tissue, with a high degree of accuracy. The relationship of the perforators aided in an "ideal" flap design. No necrosis was noted in any of these cases. It appears from this study that MRI can be a useful imaging modality, to assess the location and number of perforators in musculocutaneous flaps.

Adult↗