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Background: Infection is a common complication following tissue expander (TE)-based breast reconstruction. Few studies have examined risk factors specifically in the unique populations encountered at safety-net hospitals. The purpose of this study was to identify predictors of TE infection at Harris Health safety-net hospitals, which serve the third most populous county in the United States., Methods: A retrospective review was performed to evaluate women over the age of 18 years who underwent TE placement at two safety-net hospitals from October 2015 to November 2022. Demographic information, medical history, operative details, and postoperative course were recorded for each individual TE. The primary outcome was TE infection, for which univariate and multivariate analysis was conducted. The secondary outcome was the time to onset of TE infection, for which a Kaplan-Meier analysis was undertaken., Results: There were 279 patients, totaling 372 breasts, meeting the inclusion criteria. The TE infection rate was 23%. Increased body mass index (BMI), diabetes, use of acellular dermal matrix (ADM), and prolonged surgical drain use were all significantly associated with TE infection in univariate and multivariate analysis. Similarly, BMI ≥30 kg/m 2 , diabetes, and ADM use were also associated with earlier onset of TE infection., Conclusions: This study demonstrated similar TE infection rates at our safety-net hospitals compared with previously reported literature. To optimize the quality of care for patients in safety-net institutions, these risk factors must be addressed in the context of the unique challenges encountered in these settings., Competing Interests: Conflict of interest statement None., (Copyright © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

The use of robotic surgical systems to perform abdominoperineal resection (APR) has recently become more prevalent. This minimally invasive approach produces fewer scars and potentially less morbidity for the patient. The rectus abdominis muscle is often used for reconstruction after APR if primary closure is not feasible or the surgical site is at high risk of wound complications. Since the traditional open harvest of this flap creates large incisions that negate the advantages of minimally invasive APR, there has been growing interest in harvesting the rectus abdominis in a similarly robotic fashion. This article reviews the technique, benefits, and limitations of this robotic technique. Compared to the traditional open harvest, robotic harvest of the rectus abdominis leaves smaller scars, provides technical benefits for the surgeon, and offers possible morbidity benefits for the patient. These advantages should be weighed against the added expense and learning curve inherent to robotic surgery., Competing Interests: Conflict of Interest None declared., (Thieme. All rights reserved.)

Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Clavicular reconstruction is typically managed conservatively. Despite demonstrating improving outcomes, including range of motion and pain, there are currently no published reports of acute reconstruction with vascularized free fibula flaps (VFFF) or vascularized periosteal extensions in adult patients with clavicular defects. VFFFs have been utilized to correct critical bony defects of the clavicle and chronic nonunions; however, descriptions following acute trauma are rare. Bony union enhancement with periosteal extension has been described in both pediatric and adult populations, but never in the case of clavicular reconstruction. Herein, we seek to fill this gap in the literature by describing the acute reconstruction of a 6.5 cm bony gap in a 29-year-old male following a gunshot wound to the chest, utilizing a 6.5 cm VFFF with periosteal extension, and inset to the internal mammary vessels. The postoperative course was uncomplicated, with bony consolidation noted by 10 weeks, and full, pain-free range of motion at 8 months, showing this technique may be a viable option following acute trauma., (© 2022 Wiley Periodicals LLC.)

Diabetic foot ulcers are a severe complication of diabetes, and their management requires a multidisciplinary approach for optimal management. When treating these ulcers, limb salvage remains the ultimate goal. In this article, we present the "hanging" free flap for the reconstruction of chronic lower extremity diabetic ulcers. This two-staged approach involves standard free flap harvest and inset; however, following inset the "hanging" pedicle is covered within a skin graft instead of making extraneous incisions within the undisturbed soft tissues or tunnels that can compress the vessels. After incorporation, a second-stage surgery is performed in 4 to 6 weeks which entails pedicle division, flap inset revision, and end-to-end reconstruction of the recipient vessel. Besides decreasing the number of incisions on diabetic patients, our novel technique utilizing the "hanging" pedicle simplifies flap monitoring and inset and allows reconstruction of recipient vessels to reestablish distal blood flow., Competing Interests: Conflict of Interest None declared., (The Korean Society of Plastic and Reconstructive Surgeons. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Background: Arteriovenous malformations are abnormal high-flow vascular anomalies that can greatly alter the structure of surrounding tissues. Treatment of symptomatic hand arteriovenous malformations must address the functional and aesthetic considerations of the hand. Nonsurgical treatment such as embolization continues to be plagued by complications such as digital ischemia and secondary need for amputation. In this study, the authors describe their experience treating hand arteriovenous malformations with wide resection and microsurgical reconstruction of the palmar arch. This technique aims to optimize postoperative function and minimize postoperative complications and recurrence., Methods: Retrospective review identified five patients who underwent surgical excision of hand arteriovenous malformations performed by two of the senior authors (W.C.P. and M.M.) between 2002 and 2020. Four patients underwent reconstruction of the palmar arch, whereas one patient underwent ray amputation of the involved index finger only. One patient required concurrent free flap for soft-tissue coverage following resection., Results: Mean age at the time of surgery was 34.6 years. After an average follow-up of 2.7 years, there were no postoperative complications, functional deficits, or recurrences. The patient who underwent ray amputation only was postoperatively noted to have pulsatile dorsal veins concerning for a persistent high-flow state, although no recurrent mass was seen at limited 1-year follow-up., Conclusions: Meticulous surgical excision with microvascular reconstruction is an acceptable technique for management of symptomatic hand arteriovenous malformations. Potential soft-tissue loss does not preclude aggressive resection. Wide excision with palmar arch reconstruction minimizes complications, optimizes functionality, and may prevent ischemia that could otherwise trigger recurrence., Clinical Question/level of Evidence: Therapeutic, IV., (Copyright © 2022 by the American Society of Plastic Surgeons.)

Background: Distal extremity defects pose a particular challenge to the reconstructive surgeon; however, advances in perforator flaps have expanded the potential reconstructive options. In this article, the authors present their experience in reconstructing distal extremity defects using a thin, cutaneous free flap based on the perforator of the first dorsal metacarpal artery: the comet flap., Methods: A retrospective review was performed on all patients who presented with a distal extremity defect and underwent reconstruction using a comet flap between 2015 and 2019. Patient demographics, flap anatomy and harvest, and postoperative course were reviewed and analyzed., Results: A total of 16 patients were included. The mean patient age was 36.5 years. Trauma was the most common cause. The average defect size was 5.4 × 3.2 cm. The average pedicle length of the comet flap ranged from 3.5 to 30 cm, depending on involvement of the radial vessels. All donor sites underwent uncomplicated closure with local rhomboid flaps. One flap was complicated by an acute venous thrombosis that was successfully treated operatively. The flap survival rate was 95 percent. All patients were able to maintain their preoperative range of motion and were satisfied with their final outcome. Follow-up time ranged from 6 to 50 months., Conclusions: Local flaps remain an important reconstructive approach for distal extremity defects; however, in complex soft-tissue injuries, free tissue transfers become necessary. The comet flap is a safe, versatile, and reliable flap for reconstructing upper and lower extremity defects that can be performed in a single procedure under regional anesthesia., Clinical Question/level of Evidence: Therapeutic, IV., (Copyright © 2022 by the American Society of Plastic Surgeons.)

Background: Although there is a rationale supporting that preoperative showering with 2% or 4% chlorhexidine gluconate (CHG) would decrease skin bacterial colonization, there is no consensus that this practice reduces the risk of surgical site infection (SSI)., Objectives: Analyze the skin concentration of CHG after preoperative showering associated with the traditional skin preparation with CHG 4% for breast surgery., Methods: Randomized controlled trial that included 45 patients, all candidates for augmentation mammaplasty, allocated into three groups (A: no preoperative showering; B: one preoperative showering; C: two preoperative showering with CHG 4%) in a 1:1:1 ratio. Skin swabs collection was performed right before the surgical incision. The samples were, then, sent to spectrophotometry in order to determine the skin concentration of CHG at the beginning of surgery., Results: The age ranged from 18 to 61 years, with a mean of 37 years old. Group C had the lowest median concentration (0.057) followed by group B (0.060) and group A (0.072), however, with no statistical significance. The areola was the place with the lowest median concentration level (0.045), followed by the axilla (0.061) and the inframammary fold (IMF) (0.069). Still, when comparing the distribution of the sites, a statistically significant difference was found only between the axilla and the areola (p = 0.022)., Conclusion: Preoperative showering with CHG 4% did not increase the concentration of this agent on the skin surface right before the surgical incision., Level of Evidence Iv: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Background: Intramuscular hemangiomas are rare, benign vascular tumors, constituting 0.8 percent of all hemangiomas. Upper extremity intramuscular hemangiomas pose diagnostic and therapeutic challenges because of their rarity, invasive nature, and potential for neurovascular involvement. The authors report a comprehensive systematic review of upper extremity intramuscular hemangioma management and a challenging case report., Methods: A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic databases were used to identify articles describing upper extremity intramuscular hemangiomas through 2019. Patient demographics, clinical presentation, management, complications, and outcomes were reviewed. Based on operative timing, cases were categorized as either "primary" (excision performed at initial diagnosis) or "secondary" (excision performed after failure of conservative treatment)., Results: Eighteen articles encompassing 25 patients were included in the authors' systematic review. Of those, 18 underwent primary excision and seven underwent secondary excision. The majority involved the forearm or antecubital region. Complete excision, evaluated by gross examination or pathology, was reported in all primary cases and 71 percent of secondary cases. Primary excisions demonstrated smaller size of mass (19.4 cm 2 versus 165.3 cm 2 ) and superior reported functional outcomes (100 percent versus 33 percent). Complications were reported in 5 percent of the primary excisions compared to 71 percent of the secondary excisions, where one complication was a fatal hematoma., Conclusions: The literature concerning upper extremity intramuscular hemangioma is limited to mostly case reports and several case series with the potential risk of bias. With careful dissection and microsurgical technique, wide local excision followed by complete reconstruction can be successfully performed at initial diagnosis for upper extremity intramuscular hemangiomas. At early stages, smaller lesion size significantly reduces the risk of functional impairment and complications., (Copyright © 2022 by the American Society of Plastic Surgeons.)

Background:  Free flaps have become the preferred reconstructive approach to restore form and function for patients presenting with complex head and neck defects. For composite, complex defects for which a regular free flap might not meet all reconstructive demands, adequate coverage can be achieved with either a single chimeric free flap or a double free flap., Methods:  We performed a single-center retrospective chart review of patients who underwent either single chimeric free flap or double free flap reconstruction. Indications for reconstruction included defects resultant from head and neck tumor or osteoradionecrosis resections. We extracted the following variables: tumor location, defect, flap(s) performed, and postoperative complications. Unpaired t -tests were performed to evaluate for statistically significant differences in complications encountered between the single chimeric versus the double free flap patient groups., Results:  In our series of 44 patients, a total of 55 single chimeric and double free flaps were performed. We found no significant difference in overall complications ( p  = 0.41) or flap/skin paddle loss ( p  = 0.45) between the groups. There were three total flap losses; two patients underwent successful salvage procedures and one patient died. The anterolateral thigh (ALT) was the most common free flap (70%) used in our series, and 98% of our patients completed successful reconstruction., Conclusion:  As the initial reconstructive effort is critical for achieving favorable long-term outcomes in complex head and neck cases, effective and safe techniques should be employed to ensure optimal delivery of care. We believe that single chimeric and double free flap techniques should be appropriately utilized as part of the armamentarium of head and neck reconstructive microsurgeons., Competing Interests: None declared., (Thieme. All rights reserved.)

Abstract: Facial nerve injuries are a common complication associated with parotidectomy. These functionally debilitating injuries are conventionally treated with nonvascularized nerve grafting; however, this reconstructive modality produces moderate donor site morbidity and has limited efficacy for repairing large defects. In addition, nonvascularized nerve grafts are highly susceptible to radiotherapy and require a well-vascularized wound bed to produce adequate therapeutic results. The fascicular turnover flap, described by Koshima et al, utilizes a single fascicle to bridge two nerve endings that are in series with no donor site morbidity. Although studies have demonstrated this technique's efficacy, there is a paucity of data regarding its use in patients undergoing facial nerve reconstruction. Herein, we describe our early clinical experience using the fascicular turnover flap to reconstruct branches of the facial nerve in patients undergoing extensive parotidectomy. Our patients underwent successful reconstruction of the nerve defects produced by parotidectomy using the fascicular turnover flap. Despite postoperative radiotherapy, both patients demonstrated complete functional recovery at six months postoperatively. Although formal head-to-head studies are needed to compare the outcomes of this technique versus conventional nerve grafting for facial nerve reconstruction, our preliminary experiences suggest that the fascicular turnover flap is a viable modality of reconstruction with great potential., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 by Mutaz B. Habal, MD.)

Total and subtotal sternectomy oncological defects can result in large deficits in the chest wall, disrupting the biomechanics of respiration. Reviewing the current literature involving respiratory function and rib motion after sternectomy, autologous rigid reconstruction was determined to provide the optimal reconstructive option. We describe a novel technique for sternal defect reconstruction utilizing a double-barrel, longitudinally oriented, vascularized free fibula flap associated with rib titanium plates fixation. Our reconstructive approach was able to deliver a physiological reconstruction, providing rigid support and protection while allowing articulation with adjacent ribs and preservation of chest wall mechanics.

Background: Since the Patient Protection and Affordable Care Act was signed into law, there has been a push away from fee-for-service payment models. The rise of bundled payments has drastically impacted plastic surgeons' incomes, especially nonsalaried surgeons in private practice. As a result, physicians must now attempt to optimize contractual reimbursement agreements (carve-outs) with insurance providers. The aim of this article is to explain the economics behind negotiating carve-outs and to offer a how-to guide for plastic surgeons to use in such negotiations., Methods: Based on work relative value units, Medicare reimbursement, overhead expenses, physician workload, and desired income, the authors present an approach that allows surgeons to evaluate the reimbursement they receive for various procedures. The authors then review factors that influence whether a carve-out can be pursued. Finally, the authors consider relevant nuances of negotiating with insurance companies., Results: Using tissue expander insertion (CPT 19357) as an example, the authors review the mathematics, thought process required, and necessary steps in determining whether a carve-out should be pursued. Strategies for negotiation with insurance companies were identified. The presented approach can be used to potentially negotiate a carve-out for any reconstructive procedure that meets appropriate financial criteria., Conclusions: Understanding practice costs will allow plastic surgeons to evaluate the true value of insurance reimbursements and determine whether a carve-out is worth pursuing. Plastic surgeons must be prepared to negotiate adequate reimbursement carve-outs whenever possible. Ultimately, by aligning the best quality patient care with insurance companies' financial motivations, plastic surgeons have the opportunity to improve reimbursement for some reconstructive procedures., (Copyright © 2021 by the American Society of Plastic Surgeons.)

Pseudarthrosis is a feared complication of spinal fusion procedures. Currently, the gold standard in prevention or treatment of pseudarthrosis is placement of nonvascularized iliac crest bone autograft. While rates of fusion are significantly higher in patients with use of nonvascularized bone autografts than with allografts, patients who have previously failed lumbar arthrodesis or those at a high risk for pseudarthrosis may benefit from a more robust, vascularized bone graft with enhanced osteogenicity. In this article, we discuss the use of iliac crest vascularized bone grafts as an adjunct for high-risk patients undergoing lumbosacral spine arthrodesis., Competing Interests: Conflict of Interest Dr. Ropper receives consulting fees from Globus Medical and Stryker, but they have no conflict with this report., (Thieme. All rights reserved.)

Advances in surgical instruments, magnification technology, perforator dissection techniques, and vascular imaging over the past decades have facilitated exponential growth in the field of microsurgery. With wide application potential including but not limited to limb salvage, breast reconstruction, lymphedema treatment, and sex affirmation surgery, microsurgery represents a critical skill set that powerfully augments the reconstructive armamentarium of plastic surgeons. Accordingly, microsurgical training is now a critical component of the plastic surgery residency education curriculum. Trainees must meet minimum microsurgery case requirements in addition to the core competencies outlined by the Accreditation Council for Graduate Medical Education. Through the use of simulation models, residency programs increasingly incorporate early skills development and assessment in microsurgery in the laboratory. Beyond residency, microsurgery fellowships offer additional exposure and refinement by offering volume, complexity, autonomy, and possible focused specialization. With continued refinement in technology and advances in knowledge, new types of simulation training models will continue to be developed and incorporated into microsurgery training curricula., (Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Reconstruction of defects of the head and face in the pediatric population requires special consideration for future growth, and at times temporization in anticipation for skeletal maturity followed by subsequent reoperation at an appropriate age. Additional challenges include more limited donor sites, smaller anastomoses, and unpredictable postoperative compliance compared with their adult counterparts. Nonetheless, successful composite bony and soft tissue, and isolated soft tissue defects in children are safely reconstructed using existing local tissue and microsurgical techniques., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Many surgeons are hesitant to use interposition vein grafting in head and neck microvascular free flap surgery because of concerns for elevated risk of flap loss., Methods: The authors conducted a review of patients who underwent head and neck free flap reconstruction between 2005 and 2015. The effect of vein grafts on flap compromise and flap loss was analyzed using univariate and multivariate models., Results: A total of 3240 free flaps were performed. Vein grafts were used in 241 flaps (7.4 percent). The free flap compromise rate was 14.5 percent with vein grafts and 3.4 percent without vein grafts (p < 0.001). The free flap loss rate was 6.4 percent with vein grafts and 1.1 percent without vein grafts (p < 0.001). Radiation therapy, chemotherapy, prior neck dissection, prior free flap, osteoradionecrosis, and multiple free flap surgery were more frequent within the vein graft group (all p < 0.001). Despite this, vein grafting was associated with an increased risk of flap compromise (adjusted OR, 4.8; 95 percent CI, 3.2 to 7.3; p < 0.001) and flap loss (adjusted OR, 5.5; 95 percent CI, 3.0 to 10.2; p < 0.001) on multivariable analysis. Individual review of each flap loss within the vein graft group identified no cases of thrombosis caused by anastomotic technical errors, arguing against the requirement of an additional anastomosis as a cause for loss of vein-grafted free flaps., Conclusions: An increased risk of free flap compromise and loss is associated with use of vein grafts. However, a 93.4 percent success rate was still achieved in notably more challenging cases where vein grafting was deemed necessary taking into consideration the pertinent risks and benefits., Clinical Question/level of Evidence: Therapeutic, III.

Objective: To demonstrate the feasibility of endoscopic extraperitoneal single site (EESS) inguinal hernia repair and compare it outcomes with the conventional totally extraperitoneal (TEP) technique., Background: TEP inguinal hernia repair is a widely accepted alternative to conventional open technique with several perioperative advantages. Transumbilical laparoendoscopic singlesite surgery (LESS) is an emerging approach and has been reported for a number of surgical procedures with superior aesthetic results but other advantages need to be proven., Patients and Methods: Thirty-eight uncomplicated inguinal hernias were repaired by EESS approach between January 2010 and January 2011. All procedures were performed through a 25 cm infraumbilical incision using the Alexis wound retractor attached to a surgical glove and three trocars. Body mass index, age, operative time, blood loss, complications, conversion rate, analgesia requirement, hospital stay, return to normal activities and patient satisfaction with aesthetic results were analysed and compared with the last 38 matched-pair group of patients who underwent a conventional TEP inguinal hernia repair by the same surgeon., Results: All procedures were performed successfully with no conversion. In both unilateral and bilateral EESS inguinal repairs, the mean operative time was longer than conventional TEP (55± 20 vs. 40± 15 min, P = 0.049 and 70± 15 vs. 55± 10 min, P = 0.014). Aesthetic result was superior in the EESS group (2.88± 0.43 vs. 2.79± 0.51, P = 0.042). There was no difference between the two approaches regarding blood loss, complications, hospital stay, time until returns to normal activities and analgesic requirement., Conclusion: EESS inguinal hernia repair is safe and effective, with superior cosmetic results in the treatment of uncomplicated inguinal hernias. Other advantages of this new technique still need to be proven.

Background: Reconstruction of sacrectomy defects following ablative surgery remains a challenge, with high complication rates in the reported literature. The size of the defect is the primary consideration for flap choice; however, the cause of intra-abdominal and flap complications remains unclear. The aim of the study was to evaluate our results for sacrectomy flap reconstruction in order to determine predictive or protecting factors for complications., Methods: A 13-year retrospective review was performed of all patients who had reconstruction for partial and total sacrectomy defects at the Mayo Clinic in Rochester, MN, USA. Demographics, flap choice, and complications were analyzed. Multivariate analysis was used to determine factors causing flap and intra-abdominal complications., Results: Fifty-four patients underwent reconstruction. Partial sacrectomy was performed in 38 (70.4%) patients, while total sacrectomy was performed in 16 (29.6%) patients. The average wound defect volume was 2136 cm(3) (range 196-13,980 cm(3)). Flaps used included gluteal (n = 15; 27.8%), rectus abdominis myocutaneous (RAM) (n = 37; 68.5%), and combined gluteal/RAM (n = 2; 3.7%). Obesity was significantly associated with intra-abdominal complications (p < 0.05) while preoperative radiotherapy and chemotherapy were not. Flap and wound healing complications were not significantly associated with any factors., Conclusions: Gluteal advancement and vertical RAM or transverse RAM flaps are both reliable options for reconstruction of sacrectomy defects. The use of acellular dermal matrix (ADM) for reconstructing the posterior abdominal wall provides a barrier between the intra-abdominal contents and flap, preventing bowel adhesions/obstruction and fistulas as well as prevents sacroperineal hernia., (Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Digital replantation has become a well-established technique among reconstructive hand surgeons. Numerous replantation centers around the world have published series with impressive survival rates. The ultimate goal of replantation is the restoration of normal hand or digital function; thus, replantation success is not solely related to the outcome of the microvascular anastomosis, but also to the adequacy of bone, tendon, skin, and nerve repairs. In this manuscript, we review the literature on upper extremity and digital replantation from its historical background to current surgical outcomes, outlining surgical indications and contraindications, and the preoperative, operative, and postoperative management of these patients.

Introduction: Obturator hernia (OH) is a rare condition and difficult to diagnose. While they account for as few as 0.073% of all hernias, mortality can be as high as 70%. The typical clinical presentation for OH is small bowel obstruction. Computed tomography is the diagnostic tool of choice. Surgical repair is mandatory in virtually all cases of OH and traditionally consists of performing an exploratory laparotomy., Presentation of Case: A 90-year-old female was admitted to our surgical service with signs of small bowel obstruction and a CT scan revealing incarcerated fatty tissue and small bowel within a left OH., Discussion: The role of laparoscopic surgery in the management of OH has been limited to elective repairs; most reports detail that the OH was found serendipitously during laparoscopic inguinal hernia operations or other pelvic procedures. A few reports describe the use of laparoscopy to treat OH associated with bowel obstruction in an emergency setting using a TAPP approach. A strict TEP hernia repair is not indicated for all patients with OH, and should rarely be performed in emergency situations given its limitation to assess or resect bowel if necessary. In selected cases, a formal exploratory laparoscopy that is negative for compromised bowel can be safely followed by a TEP repair using the same umbilical access as shown in our patient., Conclusion: A 90-year-old female with a small bowel obstruction related to an incarcerated OH was treated effectively with an extraperitoneal laparoscopic approach.

Objectives: We present a method to quantify the inflammatory processes that drive abdominal aortic aneurysm (AAA) development that may help predict the rate of growth and thus guide medical and surgical management. We use an in vivo optical molecular imaging approach to quantify protease activity within the walls of AAAs in a rodent model., Methods: AAAs were generated in mice by topical application of calcium chloride, followed by the administration of the MMP inhibitor doxycycline for 3 months. After this time period, an enzyme-activatable optical molecular imaging agent sensitive to MMP activity was administered, and MMP proteolytic activity was measured in vivo. Histology and in situ zymography were performed for validation. AAAs were also generated in rats, and MMP activity within the walls of the AAAs was also quantified endovascularly., Results: A dose-dependent response of AAA growth rate to doxycycline administration was demonstrated, with high doses of the drug resulting in nearly complete suppression of aneurysm formation. There was a direct relationship between the rate of aneurysmal growth and measured MMP activity, with a linear best-fit well approximating the relationship. We additionally performed endovascular imaging of AAAs in rats and demonstrated a similar suppression of intramural MMP activity following doxycycline administration., Conclusions: We present an in vivo evaluation of MMP activity within the walls of AAAs in rodents and show a direct, linear relationship between proteolytic activity and aneurysmal growth. We also illustrate that this functional imaging method can be performed endovascularly, demonstrating potential pre-clinical and clinical applications., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Real-time in vivo imaging of the microvasculature may help both earlier clinical detection of disease and the understanding of tumor-host interaction at various stages of progression. In vivo confocal and multiphoton microscopy is often hampered by bulky optics setup and has limited access to internal organs. A fiber-optic setup avoids these limitations and offers great user maneuverability. We report here the in vivo validation of a fiber-optic confocal fluorescence microprobe imaging system. In addition, we developed an automated fractal-based image analysis to characterize microvascular morphology based on vessel diameter distribution, density, volume fraction, and fractal dimension from real-time data. The system is optimized for use in the far-red and near-infrared region. The flexible 1.5-mm-diameter fiber-optic bundle and microprobe enable great user maneuverability, with a field of view of 423 x 423 microm and a tissue penetration of up to 15 microm. Lateral and axial resolutions are 3.5 and 15 microm. We show that it is possible to obtain high temporal and spatial resolution images of virtually any abdominal viscera in situ using a far-red blood pool imaging probe. Using an orthotopic model of pancreatic ductal adenocarcinoma, we characterized the tumor surface capillary and demonstrated that the imaging system and analysis can quantitatively differentiate between the normal and tumor surface capillary. This clinically approved fiber-optic system, together with the fractal-based image analysis, can potentially be applied to characterize other tumors in vivo and may be a valuable tool to facilitate their clinical evaluation.