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Biomedical subjects

Robert J Allen

Publications and source records attributed to Robert J Allen.

16 recordsLinked to original sources
PubMed2006

Breast reconstruction using perforator flaps.

BACKGROUND: Perforator flaps allow the transfer of the patient's own skin and fat in a reliable manner with minimal donor-site morbidity. The deep inferior epigastric artery (DIEP) and superficial inferior epigastric artery (SIEA) flaps transfer the same tissue from the abdomen to the chest for breast reconstruction as the TRAM flap without sacrificing the rectus muscle or fascia. Gluteal artery perforator (GAP) flaps allow transfer of tissue from the buttock, also with minimal donor-site morbidity. INDICATIONS: Most women requiring tissue transfer to the chest for breast reconstruction or other reasons are candidates for perforator flaps. Absolute contraindications to perforator flap breast reconstruction include history of previous liposuction of the donor site or active smoking (within 1 month prior to surgery). ANATOMY AND TECHNIQUE: The DIEP flap is supplied by intramuscular perforators from the deep inferior epigastric artery and vein. The SIEA flap is based on the SIEA and vein, which arise from the common femoral artery and saphenous bulb. GAP flaps are based on perforators from either the superior or inferior gluteal artery. During flap harvest, these perforators are meticulously dissected free from the surrounding muscle which is spread in the direction of the muscle fibers and preserved intact. The pedicle is anastomosed to recipient vessels in the chest and the donor site is closed without the use of mesh or other materials. CONCLUSIONS: Perforator flaps allow the safe and reliable transfer of abdominal tissue for breast reconstruction.

Breast Neoplasms↗
PubMed2006

Breast reconstruction with gluteal artery perforator flaps.

BACKGROUND: Several alternatives exist for breast cancer reconstruction with perforator flaps. For those patients in whom the buttock is the best choice as a source for autologous tissue, the IGAP and SGAP flaps are an excellent option. These flaps allow the reliable transfer of skin and soft tissue from the buttock without the associated donor site morbidity of a muscle flap. INDICATIONS: Most women requiring tissue transfer to the chest from the buttock for breast reconstruction or other reasons are candidates for IGAP or SGAP flaps. Do to an improved donor site contour and scar, we now prefer to use the IGAP to the SGAP flap. Absolute contraindications specific to perforator flap breast reconstruction in our practice include history of previous liposuction of the donor site or active smoking (within 1 month prior to surgery). ANATOMY AND TECHNIQUE: IGAP and SGAP flaps are based on perforators from either the superior or inferior gluteal artery. These perforators are carefully dissected free from the surrounding gluteus maximus muscle, which is spread in the direction of the muscle fibres and safely preserved. The vascular pedicle is anastomosed to recipient vessels in the chest and the donor site closed primarily. CONCLUSIONS: IGAP and SGAP flaps allow the safe and reliable transfer of tissue from the buttock for breast reconstruction as an alternative to soft tissue transfer from an abdominal donor site or even as a first choice in selected patients.

Arteries↗
PubMed2006

Breast reconstruction with the deep inferior epigastric perforator flap: history and an update on current technique.

Perforator flaps allow the transfer of the patient's own skin and fat in a reliable manner with minimal donor site morbidity. For breast reconstruction, the abdomen typically is our primary choice as a donor site. The deep inferior epigastric perforator (DIEP) flap remains our first choice as an abdominal perforator flap and has become a mainstay for the repair of mastectomy defects. It allows the transfer of the same tissue from the abdomen to the chest for breast reconstruction as the TRAM flap without sacrifice of the rectus muscle or fascia. We discuss our current techniques and specific issues related to the surgery. We present the results of 1095 cases of free tissue transfers from the abdomen for reconstruction of the breast.

Abdominal Wall↗
PubMed2006

The in-the-crease inferior gluteal artery perforator flap for breast reconstruction.

BACKGROUND: Perforator free flaps harvested from the abdomen or buttock are excellent options for breast reconstruction. They enable the reconstructive surgeon to recreate a breast with skin and fat while leaving muscle at the donor site undisturbed. The gluteal artery perforator free flap using buttock tissue was first introduced by the authors' group in 1993. Of the 279 gluteal artery perforator flaps, the authors have performed for breast reconstruction, 220 have been based on the superior gluteal artery and 59 have been based on the inferior gluteal artery. The authors have found that for some women with excess tissue in the upper buttock and hip area, use of the gluteal artery perforator flap resulted in an improvement at the donor site, whereas for others the aesthetic unit of the buttock was clearly disrupted. Therefore, the authors have recently been placing the scar in the inferior buttock crease to improve donor-site aesthetics. METHODS: The authors have now performed 31 in-the-crease inferior gluteal artery perforator free flaps for breast reconstruction and found that the results are very favorable. RESULTS: The removal of tissue from the inferior buttock results in a tightened, lifted appearance. The resultant scar is well concealed within the infrabuttock crease, and exposure or injury of the sciatic nerve has not occurred. Extended beveling at this site is also possible, with less risk of causing an unsightly depression. The final aesthetic result of the scar lying within the inferior buttock crease is very favorable. All patients report satisfaction with the donor site. Complications included one total flap loss, two reoperations for venous congestion, one hematoma, two cases with delayed wound healing at the recipient site, and one with delayed wound healing at the buttock. CONCLUSION: The in-the-crease inferior gluteal artery perforator flap from the buttock is now the authors' primary alternative to the deep inferior epigastric perforator flap from the abdomen for breast reconstruction.

Adult↗
PubMed2005

Follow-up costs increase the cost disparity between endovascular and open abdominal aortic aneurysm repair.

OBJECTIVE: This study compared the hospital and follow-up costs of patients who have undergone endovascular (EVAR) or open (OR) elective abdominal aortic aneurysm repair. METHODS: The records of 195 patients (EVAR, n = 55; OR, n = 140) who underwent elective aortic aneurysm repair between 1995 and 2004 were reviewed. Primary costing data were analyzed for 54 EVAR and 135 OR patients. Hospital costs were divided into preoperative, operative, and postoperative costs. Follow-up costs for EVAR patients were recorded, with a median follow-up time of 12 months. RESULTS: Mean preoperative costs were slightly higher in the EVAR group (AU $961/US $733 vs AU $869/US $663; not significant). Operative costs were significantly higher in the EVAR group (AU $16,124/US $12,297 vs AU $6077/US $4635; P < .001); this was entirely due to the increased cost of the endograft (AU $10,181/US $7,765 for EVAR vs AU $476/US $363 for OR). Postoperative costs were significantly reduced in the EVAR group (AU $4719/US $3599 vs AU $11,491/US $8,764; P < .001). Total hospital costs were significantly greater in the EVAR group (AU $21,804/US $16,631 vs AU $18,437/US $14,063; P < .001). The increase in total hospital costs was due to a significant difference in graft costs, which was not offset by reduced postoperative costs. The average follow-up cost per year after EVAR was AU $1316/US $999. At 1 year of follow-up, EVAR remained significantly more expensive than OR (AU $23,120/US $17,640 vs AU $18,510/US $14,122; P < .001); this cost discrepancy increased with a longer follow-up. CONCLUSIONS: EVAR results in significantly greater hospital costs compared with OR, despite reduced hospital and intensive care unit stays. The inclusion of follow-up costs further increases the cost disparity between EVAR and OR. Because EVAR requires lifelong surveillance and has a high rate of reintervention, follow-up costs must be included in any cost comparison of EVAR and OR. The economic cost, as well as the efficacy, of new technologies such as EVAR must be addressed before their widespread use is advocated.

Aged↗
PubMed2005

Algorithm for autologous breast reconstruction for partial mastectomy defects.

BACKGROUND: The use of lateral thoracic skin and fat for breast reconstruction is advantageous because it does not require the use of muscle transfer, and the donor-site incision is well hidden under the arm. In patients with redundant skin at the thoracic flank, use of this tissue has the added benefit of removal of an unsightly roll. The lateral thoracic skin and fat flap can be harvested using microsurgical technique based on three different pedicles: the thoracodorsal artery perforators; a direct cutaneous branch of the thoracodorsal, axillary, or lateral thoracic arteries; and the lateral thoracic intercostal perforating vessel. METHODS: The authors describe the techniques for harvest of lateral thoracic tissue based on each of the pedicle options. A case is then presented to illustrate each option, and an algorithm is suggested for deciding which pedicle to use. RESULTS: The authors have used lateral thoracic tissue for partial breast reconstruction for a variety of defects. In this report, the authors review the results of three illustrative cases. CONCLUSIONS: Partial breast reconstruction may be required for patients after breast-conserving therapy or after breast reconstruction by other methods. Lateral thoracic tissue can be safely transferred to correct defects in treated or reconstructed breast, or to obtain symmetry. Knowledge of the vascular anatomy to this region is helpful in understanding the pedicle options when harvesting this tissue. The authors present an algorithm for determining which pedicle is most appropriate for the transfer of lateral thoracic tissue for partial breast reconstruction.

Adult↗
PubMed2004

A 10-year retrospective review of 758 DIEP flaps for breast reconstruction.

This study examined 758 deep inferior epigastric perforator flaps for breast reconstruction, with respect to risk factors and associated complications. Risk factors that demonstrated significant association with any breast or abdominal complication included smoking (p = 0.0000), postreconstruction radiotherapy (p = 0.0000), and hypertension (p = 0.0370). Ninety-eight flaps (12.9 percent) developed fat necrosis. Associated risk factors were smoking (p = 0.0226) and postreconstruction radiotherapy (p = 0.0000). Interestingly, as the number of perforators increased, so did the incidence of fat necrosis. There were only 19 cases (2.5 percent) of partial flap loss and four cases (0.5 percent) of total flap loss. Patients with 45 flaps (5.9 percent) were returned to the operating room before the second-stage procedure. Patients with 29 flaps (3.8 percent) were returned to the operating room because of venous congestion. Venous congestion and any complication were observed to be statistically unrelated to the number of venous anastomoses. Overall, postoperative abdominal hernia or bulge occurred after only five reconstructions (0.7 percent). Complication rates in this large series were comparable to those in retrospective reviews of pedicle and free transverse rectus abdominis musculocutaneous flaps. Previous studies of the free transverse rectus abdominis musculocutaneous flap described breast complication rates ranging from 8 to 13 percent and abdominal complication rates ranging from 0 to 82 percent. It was noted that, with experience in microsurgical techniques and perforator selection, the deep inferior epigastric perforator flap offers distinct advantages to patients, in terms of decreased donor-site morbidity and shorter recovery periods. Mastery of this flap provides reconstructive surgeons with more extensive options for the treatment of postmastectomy patients.

Adolescent↗
PubMed2004

Reconstruction of a partial mastectomy defect with the superficial inferior epigastric artery (SIEA) flap.

A case in which a superficial inferior epigastric artery (SIEA) flap was used to reconstruct a partial mastectomy defect is described. The SIEA vessels have been shown to be predictable and to match well with the recipient internal mammary vessels. In addition, this flap does not require opening of the anterior rectus sheath, and it is possible to design a smaller flap, which would allow closure at the donor site without translocation of the umbilicus. The risk of developing an abdominal hernia or bulge is therefore nonexistent, and a very low and more inconspicuous scar is produced, both of which are advantages for the patient.

Breast Neoplasms↗
PubMed2003

Autogenous breast reconstruction with the deep inferior epigastric perforator flap.

Muscle-sparing autogenous breast reconstruction has enhanced the multidisciplinary care that is available to patients who have breast cancer. The DIEP flap has proven reliability, a low complication rate, and is applicable to many clinical scenarios (Figs. 8-12). Avoidance of muscle sacrifice in the abdomen ultimately translates into greater patient satisfaction. The increased demands, in terms of surgical expertise, are more than offset by decreased postoperative pain and decreased donor site morbidity. The methods that were used to innovate the DIEP flap have been applied to other donor sites and the available options for patients have been expanded.

Epigastric Arteries↗
PubMed2003

Anterolateral thigh flap for breast reconstruction: review of the literature and case reports.

More women than ever before are undergoing mastectomies secondary to increased awareness and screening. This has also caused a corresponding increase in the number of breast reconstructions requested each year. The demand for improved results has fueled recent advances in new techniques. Aside from implant reconstruction, the methods now being employed are related to autogenous donations and reconstruction. Currently, the most commonly used techniques for autogenous breast reconstruction are the DIEP (deep inferior epigastric perforator) and TRAM (transverse rectus abdominis myocutaneous) flaps from the lower abdomen. The anterolateral thigh flap is a type of perforator flap usually described for use in head and neck reconstruction. The authors have discovered this flap's utility as an alternative in autogenous breast reconstruction when the abdomen is not available as a donor site. A review of the literature reveals a dearth of experience in using the anterolateral thigh flap for breast reconstruction. The article reviews the literature with regard to current uses of the anterolateral thigh flap, and then reports three case studies which highlight the thigh flap as an excellent alternative for breast reconstruction in selected patients.

Adult↗
PubMed2003

Autogenous augmentation mammaplasty with microsurgical tissue transfer.

Many patients dream of reducing their abdominal or gluteal fat tissue and, in the same procedure, enlarging their breasts without the need for implants and their related problems. Following this demand, a new "natural" alternative to breast augmentation with autogenous tissue is presented. Since 1993, 16 patients have undergone either unilateral or bilateral breast augmentation with free fat transfer. These 20 augmentation mammaplasties consisted of nine deep inferior epigastric perforator flaps, eight superior gluteal artery perforator flaps, and three superficial inferior epigastric artery flaps. The postoperative results were judged aesthetically by independent examiners and by the patients according to Netscher's score. The additional operations for final shaping of the breasts and the postoperative complications at the donor and recipient sites are reported. The augmented breasts improved the aesthetic proportions more than 100 percent. All flaps survived, and except for minor postoperative complications such as small areas of wound dehiscence, the breasts could be shaped aesthetically in a second-stage procedure several weeks later. Breast augmentation with autogenous tissue offers a natural alternative to alloplastic augmentation mammaplasty.

Adipose Tissue↗
PubMed2003

The "Gent" consensus on perforator flap terminology: preliminary definitions.

Due to its increasing popularity, more and more articles on the use of perforator flaps have been reported in the literature during the past few years. Because the area of perforator flaps is new and rapidly evolving, there are no definitions and standard rules on terminology and nomenclature, which creates confusion when surgeons try to communicate and compare surgical techniques. This article attempts to represent the opinion of a group of pioneers in the field of perforator flap surgery. This consensus was reached after a terminology consensus meeting held during the Fifth International Course on Perforator Flaps in Gent, Belgium, on September 29, 2001. It stipulates not only the definitions of perforator vessels and perforator flaps but also the correct nomenclature for different perforator flaps. The authors believe that this consensus is a foundation that will stimulate further discussion and encourage further refinements in the future.

Humans↗
PubMed2003

The thoracodorsal artery perforator flap: anatomic basis and clinical application.

Based on the dissection of 20 fresh cadavers, the authors have detailed further the vascular anatomy of the thoracodorsal artery and its cutaneous perforator vessels. The thoracodorsal artery showed a constant bifurcation into a horizontal branch and a lateral branch, located on the deep surface of the latissimus dorsi muscle 4 cm (range, 3-6 cm) distal to the inferior scapular border and 2.5 cm (range, 1-4 cm) medial to the lateral free margin of the muscle. In 20 specimens there was a total of 64 musculocutaneous perforators larger than 0.5 mm. Thirty-six perforators (56%) originated from the lateral branch and 28 perforators (44%) originated from the horizontal branch. All perforators originated within a distance of 8 cm from the neurovascular hilus and ran in proximity with the horizontal or lateral branches. In 11 dissections (55%) there was also a direct cutaneous branch originating from the extramuscular course of the thoracodorsal artery before the neurovascular hilus. This cutaneous branch did not pierce the latissimus muscle but rounded the lateral muscle edge and supplied the overlying subcutaneous tissue and skin. It is hoped that the constant anatomy will encourage surgeons in the future to use the thoracodorsal artery perforator flap more often.

Adult↗
PubMed2002

Laser-activated membrane introduction mass spectrometry for high-throughput evaluation of bulk heterogeneous catalysts.

Laser-activated membrane introduction mass spectrometry (LAMIMS), a high-throughput screening method, evaluates heterogeneous catalysts under realistic reactor conditions. It is a precise, versatile system requiring no moving parts. The catalyst array is supported on carbon paper overlaid upon a silicone rubber membrane configured in a variation of membrane introduction mass spectrometry as introduced by Cooks. The carbon paper serves as a heat-dissipating gas diffusion layer that permits laser heating of catalyst samples far above the decomposition temperature of the polymer membrane that separates the array from the mass spectrometer vacuum chamber. A computer-controlled CO2 bar code writing laser is used for fine-tune heating of the catalyst spots above the base temperature of the LAMIMS reactor. The detailed design and performance of LAMIMS is demonstrated on arrays of "real world" bulk water-gas shift catalysts using natural and isotopically labeled reactor feed streams. A bulk catalyst array spot can be evaluated for activity and selectivity in as little as 1.5 min. All array screening results were confirmed by industrial microreactor evaluations.

Journal Article↗
PubMed2002

Radiation effects on breast reconstruction with the deep inferior epigastric perforator flap.

Immediate breast reconstruction has important advantages over delayed reconstruction, including a shorter operative time and decreased psychological distress for the patient. However, the authors' experiences with the deep inferior epigastric perforator flap demonstrate variable aesthetic outcomes among patients who undergo radiation postoperatively. To establish an association between radiation and poor postoperative results, a matched-pairs analysis was conducted. Thirty irradiated patients were paired with 30 nonirradiated patients, according to age and body mass index. For each group, the incidence of fat necrosis, fibrosis/shrinkage, and flap contracture was recorded. In addition, an aesthetic evaluation was conducted to compare before-and-after images of 10 irradiated patients with those of 10 nonirradiated patients from similar time periods. The images were randomized and blindly evaluated by a panel of eight judges. A five-point scale was used to evaluate symmetry, aesthetic proportion, and the appearance of the superior pole. Statistical analysis demonstrated a significant difference in the score changes for irradiated and nonirradiated patients, according to all three criteria. Nonirradiated patient scores increased by one-half point, and irradiated patient scores decreased by one-half point. In addition, the incidences of fat necrosis, fibrosis, and flap contracture were all significantly higher among the irradiated group. These results suggest that when possible, reconstruction should be delayed until after radiation therapy is complete. Persons who smoke or are obese may be at particular risk for complications following radiation therapy.

Adult↗