Surgical and Ophthalmologic Outcomes of Reconstruction in Patients Treated With Eye-Sparing Surgery and Radiation Therapy for Tumors of the Lacrimal Drainage Apparatus.

INTRODUCTION: Tumors involving the lacrimal drainage apparatus can be effectively treated with oncologic eye-sparing resection, immediate reconstruction, and adjuvant radiation. The extirpative technique is well described, whereas the reconstructive approach and outcomes are limited and largely anecdotal. The present study describes the largest series in the literature evaluating outcomes after reconstruction after globe-preserving oncologic resection. METHODS: A retrospective review was performed for all patients undergoing reconstruction after resection of lacrimal gland tumors from 2008 to 2019. Reconstruction and ophthalmologic outcomes were assessed. RESULTS: Of the 17 patients included, 2 underwent complex repair, 6 were reconstructed with a locoregional flap, and 9 underwent free flap reconstruction. All patients were treated with adjuvant radiation therapy. The median follow-up was 19 months (range, 5-126 months). Defects reconstructed with free flaps had lower rates of wound dehiscence and fistula formation compared with those reconstructed with other techniques (11% vs 25%, P = 0.45). Patients undergoing reconstruction with free tissue transfer also tended to have lower rates of ectropion, keratopathy and decreased visual acuity compared with those undergoing nonmicrosurgical reconstruction (33% vs 50%, P = 0.48; 11% vs 38%, P = 0.20; 56% vs 75%, P = 0.40, respectively). These differences were not statistically significant. CONCLUSIONS: This is the first study to compare reconstructive and functional outcomes of nonmicrosurgical reconstruction and microsurgical free tissue transfer in the setting of eye-sparing surgery for tumors of the lacrimal drainage apparatus. Although various reconstructive options are feasible, microsurgical free tissue transfer is often used at our center and is associated with reliable outcomes.

Evaluation of Sidestream Darkfield Microscopy for Real-Time Imaging Acellular Dermal Matrix Revascularization.

BACKGROUND: Acellular dermal matrices (ADMs) serve as a regenerative framework for host cell integration and collagen deposition to augment the soft tissue envelope in ADM-assisted breast reconstruction-a process dependent on vascular ingrowth. To date noninvasive intra-operative imaging techniques have been inadequate to evaluate the revascularization of ADM. METHODS: We investigated the safety, feasibility, and efficacy of sidestream darkfield (SDF) microscopy to assess the status of ADM microvascular architecture in 8 patients at the time of tissue expander to permanent implant exchange during 2-stage ADM-assisted breast reconstruction. The SDF microscopy is a handheld device, which can be used intraoperatively for the real-time assessment of ADM blood flow, vessel density, vessel size, and branching pattern. The SDF microscopy was used to assess the microvascular architecture in the center and border zone of the ADM and to compare the native, non-ADM-associated capsule in each patient as a within-subject control. RESULTS: No incidences of periprosthetic infection, explantation, or adverse events were reported after SDF image acquisition. Native capsules demonstrate a complex, layered architecture with an average vessel area density of 14.9 mm/mm and total vessel length density of 12.3 mm/mm. In contrast to native periprosthetic capsules, ADM-associated capsules are not uniformly vascularized structures and demonstrate 2 zones of microvascular architecture. The ADM and native capsule border zone demonstrates palisading peripheral vascular arcades with continuous antegrade flow. The central zone of the ADM demonstrates punctate perforating vascular plexi with intermittent, sluggish flow, and intervening 2- to 3-cm watershed zones. CONCLUSIONS: Sidestream darkfield microscopy allows for real-time intraoperative assessment of ADM revascularization and serves as a potential methodology to compare revascularization parameters among commercially available ADMs. Thr SDF microscopy demonstrates that the periprosthetic capsule in ADM-assisted implant-based breast reconstruction is not a uniformly vascularized structure.

Short-term application of doxorubicin chemotherapy immunosuppressive side effects for composite tissue allotransplantation.

BACKGROUND: Adjuvant chemotherapy is often required for the treatment of bone cancers after tumor resection, which often results in a large continuity defect. The immunosuppressive side effects could instead be exploited to allow immediate reconstruction with a composite tissue allograft (CTA) that would provide for replacement of tissues. We used a short course of doxorubicin to achieve a novel method of immunosuppression in a rat model undergoing CTA to create an immunological environment for allograft survival. MATERIALS & METHODS: The Institutional Animal Care and Use Committee-approved protocol consisted of 3 experimental groups. Groups 2 and 3 consisted of Brown Norway rats (n = 5) as allograft donors and Lewis rats (n = 5) as transplant recipients. An abdominal wall CTA was harvested off the superficial inferior epigastric vessels. Doxorubicin therapy was administered in group 3 animals. Survival of the CTA was assessed by physical examination and histological analysis. RESULTS: Allotransplant without treatment showed complete clinical and histologic rejection by day 7. Allotransplant rats treated with doxorubicin had clinically and histologically normal grafts through day 10. Kaplan-Meier survival analysis showed a statistically significant difference, with increased CTA survival time to end point with doxorubicin treatment, from a mean of 8.8 days in group 2 to 16.4 days in group 3. CONCLUSIONS: Allotransplant flaps without treatment developed complete clinical and histological rejection. The allotransplant group which received doxorubicin showed a delay of allograft rejection with an 86% increased CTA graft survival time. This demonstrates the feasibility of the immunosuppression side effect caused by chemotherapy to prevent rejection of a CTA.

Fenestration Improves Acellular Dermal Matrix Biointegration: An Investigation of Revascularization with Photoacoustic Microscopy.

BACKGROUND: Acellular dermal matrices have revolutionized alloplastic breast reconstruction. Furthering our knowledge of their biointegration will allow for improved design of these biomaterials. The ideal acellular dermal matrix for breast reconstruction would provide durable soft-tissue augmentation while undergoing rapid biointegration to promote physiologic elasticity and reduced infectious complications. The inclusion of fenestrations in their design is thought to promote the process of biointegration; however, the mechanisms underlying this theory have not been evaluated. METHODS: Biointegration of standard and fenestrated acellular dermal matrices was assessed with serial photoacoustic microscopic imaging, in a murine dorsal skinfold window chamber model specifically designed to recapitulate the microenvironment of acellular dermal matrix-assisted alloplastic breast reconstruction. Photoacoustic microscopy allows for a serial, real-time, noninvasive assessment of hemoglobin content and oxygen saturation in living tissues, generating high-resolution, three-dimensional maps of the nascent microvasculature within acellular dermal matrices. Confirmatory histologic and immunohistochemical assessments were performed at the terminal time point. RESULTS: Fenestrated acellular dermal matrices demonstrated increased fibroblast and macrophage lineage host cell infiltration, greater mean percentage surface area vascular penetration (21 percent versus 11 percent; p = 0.08), and greater mean oxygen saturation (13.5 percent versus 6.9 percent; p < 0.05) than nonfenestrated matrices by 2 weeks after implantation. By 21 days, host cells had progressed nearly 1 mm within the acellular dermal matrix fenestrations, resulting in significantly more vascularity across the top of the fenestrated matrix (3.8 vessels per high-power field versus 0.07 vessels per high-power field; p < 0.05). CONCLUSIONS: Inclusion of fenestrations in acellular dermal matrices improves the recellularization and revascularization that are crucial to biointegration of these materials. Future studies will investigate the optimal distance between fenestrations.

CASE REPORT Complex Wound Closure of Partial Sacrectomy Defect With Human Acellular Dermal Matrix and Bilateral V to Y Gluteal Advancement Flaps in a Pediatric Patient.

OBJECTIVE: Sacrectomy creates a large, complex tissue defect that presents a reconstructive challenge for plastic surgeons. Several myocutaneous flaps have been described for reconstruction following sacral tumor extirpation; however, current publications focus on the reconstructive options applicable to adults. We present a method of reconstruction following sacral tumor extirpation in a pediatric patient. METHODS: The patient was 22 months old and in need of complex closure following low sacral amputation (S3-S4 osteotomy) and en bloc resection of a yolk sac tumor. Following tumor extirpation, the patient was left with a complex defect including extensive dead space, multiple exposed nerve roots, projection of the rectum into the wound, and inadequate soft tissue for primary closure. RESULTS: Reconstruction with human acellular dermal matrix to address the risk of posterior rectal herniation and bilateral gluteal V to Y advancement flaps for obliteration of the dead space allowed for durable closure of the surgical defect. CONCLUSIONS: This represents the first case report documenting sacral resection and reconstruction with bilateral V to Y gluteal advancement flaps in a pediatric patient.