Extreme Limb Salvage: The Thin SCIP Flap for Distal Amputation Coverage in Highly Comorbid Patients

BACKGROUND

Limb length preservation is correlated with overall survival. Successful free flap coverage of forefoot, midfoot, and hindfoot amputations can prevent more proximal below-knee amputations but is challenging in patients with multiple comorbidities. The thin superficial circumflex iliac artery perforator (SCIP) flap is well-suited for these patients, as it provides thin, pliable tissue from a favorable donor site.

METHODS

A retrospective review of all patients with distal amputations requiring coverage with a thin SCIP flap between 2016 to 2022 was performed. Patient demographics, amputation levels, and wound characteristics in addition to flap and microsurgery details were analyzed. The primary outcome was limb salvage. Secondary outcomes included partial flap necrosis, flap revision rate, and additional postoperative complications.

RESULTS

Thirty-two patients (mean age, 57.3 years) underwent reconstruction of forefoot, midfoot, and hindfoot amputations with thin SCIP flaps (mean follow-up, 36 months). Twenty-eight patients (87.5%) had diabetes, 27 (84.4%) had peripheral artery disease, and 15 (46.9%) were dialysis-dependent. Average flap size was 59.5 cm 2 and average flap thickness was 5.7 mm. Successful limb salvage was achieved in 27 patients (84.3%). Three cases (9.4%) had total flap loss. Twenty-one flaps (65.6%) had partial necrosis, of which 12 (57.1%) healed with conservative management and 7 (33.3 %) healed after late revision.

CONCLUSIONS

The thin SCIP flap is a useful option for coverage of distal pedal amputations in patients with significant comorbidities. Despite higher rates of partial flap necrosis, free flap reconstruction allowed for high rates of limb salvage in a challenging patient population.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

The Free Superficially Based Low-Abdominal Mini Flap for Oncoplastic Breast Reconstruction

SUMMARY

Volume replacement in oncoplastic breast reconstruction most commonly uses pedicled flaps. In thin patients with small breasts, free-tissue transfer may be better suited to preserve breast size. Evidence on microvascular oncoplastic reconstruction is limited, and reconstruction has often required sacrifice of potential future donor sites. The free superficially based low-abdominal mini (SLAM) flap uses a narrow strip of lower abdominal tissue based on superficial perfusion of the abdominal wall that is anastomosed to chest wall perforators to preserve the ability to perform future abdominally based autologous breast reconstruction. Five patients underwent reconstruction with SLAM flaps for immediate oncoplastic reconstruction. Their mean age was 49.8 years, and their mean body mass index was 23.5. Tumor location was most commonly in the lower outer quadrant (40%). Average lumpectomy weight was 30 g. Two flaps were based on the superficial inferior epigastric artery, and three, on the superficial circumflex iliac artery. Recipient vessels included internal mammary perforators (40%), serratus branch (20%), lateral thoracic vessel branch (20%), and lateral intercostal perforators (20%). All patients underwent radiation therapy without delay and maintained volume, symmetry, and contour at an average period of 11.7 months after surgery. There were no cases of flap loss, fat necrosis, or delayed wound healing. The free SLAM flap allows for immediate oncoplastic breast reconstruction in thin, small-breasted patients with limited regional tissue without sacrificing future potential donor sites for autologous breast reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Role of pinch in Argon impurity transport in ohmic discharges of Aditya-U Tokamak

We present experimental results of the trace argon impurity puffing in the ohmic plasmas of Aditya-U tokamak performed to study the argon transport behaviour. Argon line emissions in visible and Vacuum Ultra Violet (VUV) spectral ranges arising from the plasma edge and core respectively are measured simultaneously. During the experiments, space resolved brightness profile of Ar1+ line emissions at 472.69 nm (3p44s 2P3/2-3p44p 2D3/2), 473.59 nm (3p44s 4P5/2-3p44p 4P3/2), 476.49 nm (3p44s 2P1/2-3p44p 2P3/2), 480.60 nm (3p44s 4P5/2-3p44p 4P5/2) are recorded using a high resolution visible spectrometer. Also, a VUV spectrometer has been used to simultaneously observe Ar13+ line emission at 18.79 nm (2s22p 2P3/2-2s2p2 2P3/2) and Ar14+ line emission at 22.11 nm (2s2 1S0-2s2p 1P1). The diffusivity and convective velocity of Ar are obtained by comparing the measured radial emissivity profile of Ar1+ emission and the line intensity ratio of Ar13+ and Ar14+ ions, with those simulated using the impurity transport code, STRAHL. Argon diffusivities ~ 12 m2/s and ~ 0.3 m2/s have been observed in the edge (ρ > 0.85) and core region of the Aditya-U, respectively. The diffusivity values both in the edge and core region are found to be higher than the neo-classical values suggesting that the argon impurity transport is mainly anomalous in the Aditya-U tokamak. Also, an inward pinch of ~ 10 m/s mainly driven by Ware pinch is required to match the measured and simulated data. The measured peaked profile of Ar density suggests impurity accumulation in these discharges.

Direct-to-implant versus autologous tissue transfer: A meta-analysis of patient-reported outcomes after immediate breast reconstruction

BACKGROUND

The effect of immediate implant and autologous breast reconstruction on complication rates has been studied extensively; however, the patient-reported outcomes for these procedures during immediate, one-stage reconstruction has yet to be comprehensively investigated.

OBJECTIVE

This study compared the patient-reported outcomes for immediate implant reconstruction with those associated with immediate autologous reconstruction to determine the advantages and disadvantages for each modality from the patient's perspective.

METHODS

A literature search of PubMed between 2010 and 2021 was performed, and 21 studies containing patient-reported outcomes were selected for the analysis. A meta-analysis of patient-reported outcome scores was performed separately for immediate breast reconstruction using autologous tissue transfer and synthetic implants.

RESULTS

Nineteen manuscripts were included, representing data on a total of 1342 patients across all studies. The pooled mean of patients' satisfaction with their breasts was 70.7 (95% CI, 69.4-72.0) after immediate autologous reconstruction and 68.5 (95% CI, 67.1-69.9) after immediate implant reconstruction, showing a statistically significant difference in outcomes (p < 0.05). The pooled mean of patients' sexual well-being was 59.3 (95% CI, 57.8-60.8) after immediate autologous reconstruction and 62.8 (95% CI, 60.7-64.8) after immediate implant reconstruction (p < 0.01). The pooled mean of patients' satisfaction with their outcome was 78.8 (95% CI, 76.2-81.3) after immediate autologous reconstruction and 82.3 (95% CI, 80.4-84.1) after immediate implant reconstruction (p < 0.05). The results of each meta-analysis were summarized on forest plots depicting the distribution of patient-reported outcome scores from each study.

CONCLUSIONS

Immediate reconstruction with implants may have a similar or greater capacity to achieve patient satisfaction and improve patients' QoL compared to those associated with immediate reconstruction with autologous tissue transfer when both procedures are available.

Microsurgery in oncoplastic breast reconstruction

Oncoplastic breast reconstruction has allowed for the optimization of oncologic and reconstructive outcomes after breast-conserving surgery (BCS). Volume replacement procedures in oncoplastic reconstruction most commonly utilize regional pedicled flaps, though several studies have reported benefits to free tissue transfer for oncoplastic partial breast reconstruction in the immediate, delayed-immediate and delayed settings. Microvascular oncoplastic breast reconstruction is a useful technique in the appropriate patients with small-to-medium size breasts and larger tumor-to-breast ratios who desire to preserve breast size, those with a paucity of regional breast tissue and patients that wish to avoid chest wall and back scars. Several free flap options for partial breast reconstruction exist, including superficially-based abdominal flaps, medial thigh-based flaps, deep inferior epigastric artery perforator (DIEP) flaps and thoracodorsal artery-based flaps. However, special consideration should be given to preserving donor sites for potential future total autologous breast reconstruction with any flap choice that should be tailored to individual recurrence risk. Aesthetically placed incisions should take recipient vessel access into consideration which include the internal mammary vessels and perforators medially, and then intercostal, serratus branch and thoracodorsal vessels laterally. The utilization of a thin strip of lower abdominal tissue based on the superficial abdominal circulation allows for a well-concealed donor site with minimal morbidity and preservation of the abdominal donor site if future total autologous breast reconstruction is needed. Optimizing outcomes requires a team-based approach to appropriately design recipient and donor-site considerations while individualizing tumor and patient-specific plans.

Initial results from near-infrared spectroscopy on ADITYA-U tokamak

Spectroscopy in vacuum ultraviolet (VUV) and visible ranges plays an important role in the investigation and diagnosis of tokamak plasmas. However, under harsh environmental conditions of fusion grade devices, such as ITER, VUV-visible systems encounter many issues due to the degradation of optical components used in such systems. Here, near-infrared (NIR) spectroscopy has become an effective tool in understanding the edge plasma dynamics. Considering its importance, a NIR spectroscopic diagnostic has been developed and installed on the ADITYA-U tokamak. The system consists of a 0.5 m spectrometer having three gratings with different groove densities, and it is coupled with a linear InGaAs photodiode array. Radiation from the ADITYA-U edge plasma has been collected using a collimating lens and optical fiber combination and transported to the spectrometer. The spectrum in the NIR range from the ADITYA-U plasma has been recorded using this system, in which Pa_β and Pa_γ along with many spectral lines from neutral and singly ionized impurities have been observed. The influxes of H and C have been estimated from measurements. The H influx value is found to be 2.8 × 10¹⁶ and 1.9 × 10¹⁶ particles cm^-2 s^-1 from neutral hydrogen lines H_α and Pa_β, respectively, and the C influx value is found to be 3.5 × 10¹⁵ and 2.9 × 10¹⁵ particles cm^-2 s^-1 from the neutral carbon and singly ionized carbon, respectively. A good agreement is seen between these results and the results obtained by using a routine photomultiplier tube based diagnostic.

Oncoplastic breast reconstruction: Principles, current techniques, and future directions

Oncoplastic breast reconstruction has improved esthetic results after breast-conserving surgery with low complication rates and stable oncologic outcomes. Basic principles can be applied across different volume displacement and replacement techniques including restoration of breast shape and symmetry through esthetic incisions while eliminating dead space. Technique selection is guided by several factors including breast size, resection-to-breast ratio, and patient desires. A surgeon familiar with all techniques will allow individualization of treatment and optimization of outcomes.

Microscope-Assisted Arterial Anastomosis in Adult Living Donor Liver Transplantation: A Systematic Review and Meta-analysis of Outcomes

BACKGROUND

 Living donor liver transplantation (LDLT) has expanded the availability of liver transplant but has been associated with early technical complications including the devastating complication of hepatic artery thrombosis (HAT), which has been reported to occur in 14% to 25% of LDLT using standard anastomotic techniques. Microvascular hepatic artery reconstruction (MHAR) has been implemented in an attempt to decrease rates of HAT. The purpose of this study was to review the available literature in LDLT, specifically related to MHAR to determine its impact on rates of posttransplant complications including HAT.

METHODS

 A systematic review was conducted using PubMed/Medline and Web of Science. Case series and reviews describing reports of microscope-assisted hepatic artery anastomosis in adult patients were considered for meta-analysis of factors contributing to HAT.

RESULTS

 In all, 462 abstracts were screened, resulting in 20 studies that were included in the meta-analysis. This analysis included 2,457 patients from eight countries. The pooled rate of HAT was 2.20% with an overall effect size of 0.00906.

CONCLUSION

 Systematic literature review suggests that MHAR during LDLT reduces vascular complications and improves outcomes posttransplant. Microvascular surgeons and transplant surgeons should collaborate when technical challenges such as small vessel size, short donor pedicle, or dissection of the recipient vessel wall are present.

Observations of visible argon line emissions and its spatial profile from Aditya-U tokamak plasma

The spectroscopic studies of medium and high Z impurities have been the subject of interest in fusion research due to their role in mitigating plasma disruption and reducing heat load on the plasma facing components. Line emissions from these impurities provide the rotation velocity and ion temperature measurements along with the understanding of the overall impurity behavior in plasma. In the Aditya-U tokamak, the spatially resolved Ar II line emissions have been observed using a high resolution multi-track spectroscopic diagnostic consisting of a 1 m Czerny-Turner spectrometer coupled with a charge coupled device (CCD) detector using seven lines of sight viewing plasma tangentially along the toroidal direction. The spatially resolved Ar II lines at 458.96 nm have been observed. The singly ionized Ar emission peaks at the radial location of ρ = 0.8 of the plasma having a minor radius of 25 cm. Moreover, a 0.5 m UV-visible spectrometer coupled with a CCD detector and having a line of sight passing through the plasma midplane from the radial port was used to record visible Ar survey spectra within the 670-810 nm wavelength range, and all these lines have been identified for further analysis.

Steal syndrome from a superficial circumflex iliac perforator artery flap in a patient with a hypoplastic posterior tibial artery and severe diabetic peripheral artery disease

The use of free flaps in lower extremity reconstructive surgery has seen growing adoption for treating tissue loss in patients with diabetes mellitus and peripheral artery disease as a means for limb preservation. The superficial circumflex iliac perforator artery (SCIP) flap is one of the most commonly utilized flaps in foot reconstruction and has demonstrated benefits over amputation. Patients with impaired vascular and neurologic function are predisposed to complications following lower extremity reconstructive surgery, particularly ischemia in the angiosomes of the arteries used for flap anastomosis. We present the case of a patient who underwent successful SCIP flap reconstruction of the calcaneus but developed gangrene in the forefoot region supplied by a hypoplastic posterior tibial artery in subsequent months. The changes in tissue oxygenation and hemoglobin distribution of the foot are shown using spatial frequency domain imaging throughout the flap healing process and eventual tissue necrosis.

The role of neurotization in autologous breast reconstruction: Can reconstruction restore breast sensation?

As the sophistication of microsurgical breast reconstruction continues to evolve, plastic surgeons are focusing on techniques to improve functional and psychosocial outcomes for patients, including breast sensation. Interest in neurotization of breast flaps, among both patients and surgeons, has grown significantly in recent years. This study aimed to review the outcomes of neurotization across autologous flap reconstructions, to provide a comprehensive analysis of the efficacy of this technique in improving postoperative sensory recovery.

Breast reconstruction in the high-risk population: current review of the literature and practice guidelines

Breast reconstruction is an important part of the cancer treatment paradigm and the psychosocial benefits are well described in the literature. Notably, breast reconstruction restores both the functional and emotional losses patients experience due to tumor resection. Post-cancer quality of life is an important benchmark of successful treatment; therefore, breast reconstruction is an essential component that should be offered whenever possible. Over time, reconstructive techniques and outcomes have improved dramatically resulting in better patient safety and decreased operative morbidity. When counseling a patient for surgery, the provider must consider all aspects of a patient's health. Ideally, breast cancer patients should be physically, emotionally, and oncologically appropriate candidates for reconstruction. However, in concerted effort to provide opportunities for as many patients as possible, the definition of who is a good candidate for reconstruction has evolved to include higher risk patients. These patients include those with advanced age, nicotine use, obesity, and significant ptosis. With improvements in surgical procedures and perioperative care, this population may also benefit from restorative surgery. However, the exact risk of complications and necessary counseling has gone largely undefined in this population. This article examines particular "high-risk" groups that may be challenging for extirpative and reconstructive surgeons and offers current guidelines for practice.

"Systematic review and meta-analysis of immediate versus delayed autologous breast reconstruction in the setting of post-mastectomy adjuvant radiation therapy"

BACKGROUND

Immediate post-mastectomy autologous breast reconstruction in breast cancer patients requiring post-mastectomy radiation therapy (PMRT) minimizes the number of operations that patients must undergo and alleviates the psychological impact of living without a breast. However, the safety and impact of radiation on the reconstructed breast remains to be established. This study aimed to compare immediate versus delayed autologous reconstruction in the setting of PMRT to determine the optimal sequencing of reconstruction and adjuvant radiation.

METHODS

A systematic review of the literature identified 292 studies meeting criteria for full-text review, 44 of which underwent meta-analysis. This represented data on 1,927 immediate reconstruction (IR) patients and 1,546 delayed reconstruction (DR) patients (3,473 total patients). Early complications included flap loss, fat necrosis, thrombosis, seroma, hematoma, infection, and skin dehiscence. Late complications included fibrosis or contracture, severe asymmetry, hyperpigmentation, and decreased flap volume.

RESULTS

Immediate breast reconstruction did not demonstrate significantly increased complication rates. Reported mean complication rates in IR versus DR groups, respectively, were fat necrosis 14.91% and 8.12% (p = 0.076), flap loss 0.99% and 1.80% (p = 0.295), hematoma 1.91% and 1.14% (p = 0.247), infection 11.66% and 4.68% (p = 0.155), and thrombosis 1.51% and 3.36% (p = 0.150). Seroma rates were significantly lower in the immediate cohort at 2.69% versus 10.57% in the delayed cohort (p = 0.042).

CONCLUSION

Complication rates are comparable between immediate and delayed breast reconstruction in the setting of PMRT. Given the patient benefits incurred by an IR algorithm, immediate autologous breast reconstruction should be considered as a viable treatment option in patients requiring PMRT.

Patient Characteristics Associated with Free Nipple Graft Reduction Mammoplasty

Purpose: Surgical approaches for reduction mammoplasty most commonly incorporate a parenchymal vascular pedicle. For patients with larger breasts where pedicle viability may be compromised due to excessive length, the free nipple graft (FNG) technique provides a safe alternative. Criteria for whether a patient should undergo a FNG remains controversial due to variable reports in the literature with small sample sizes and inherent surgeon-dependent bias. To address this, we sought to investigate perioperative factors associated with performing FNGs at our institution in order to better elucidate specific indications for this surgery.

Methods: A retrospective chart review was performed for 323 patients who underwent a reduction mammoplasty from August 2009 to July 2019 at Keck Hospital and LAC+USC Medical Center. Data regarding patient demographics, comorbidities, pre-operative breast characteristics, and post-operative complications were extracted. Studentʼs t-test, Fisherʼs exact test, and logistic regression were performed in R.

Results: Of 323 patients, 15 received an FNG. Independent variables analyzed included: age, body mass index (BMI), obesity, smoking, diabetes, hypertension, surgical indication, sternal notch-to-nipple length, nipple-to-inframammary fold length, and weight of breast specimens removed. BMI, obesity, gigantomastia, and weight of specimen resected were significantly associated with use of the FNG (p < 0.001, p < 0.05, p < 0.0001, p < 0.0001, respectively). Regression analysis revealed that patients who had an average of more than 1500 g of tissue removed from each breast were 1.41 (95% CI: 1.17-1.71, p<0.001) times more likely to undergo an FNG procedure than those who had less than 1500 g of tissue removed. Demographic data and breast characteristics, such as notch-to-nipple length and nipple-to-inframammary fold length, were not significantly associated.

Conclusion: Total weight of the breast specimens removed and BMI were significantly associated with the FNG technique. Removing more than 1500 g gof total breast tissue was also significantly correlated. These findings may guide surgeons during the decision-making process of when to use an FNG.

Vascularized Lymph Node Transfer: A Primer for the Radiologist

Lymphedema, the accumulation of lymphatic fluid in the tissues, is a chronic disease and a major cause of long-term morbidity and disability. Lymphedema is usually a secondary condition, often caused by prior oncologic therapy, such as surgery for cancers, radiation therapy, and chemotherapy. Treatment for lymphedema has traditionally been conservative and limited, but new surgical and microsurgical procedures have arisen in recent years. Vascularized lymph node transfer (VLNT) is one of the most promising new microsurgeries. VLNT involves the transfer of functional lymph nodes (LNs) from a healthy donor site to an area of the body with damaged or diseased lymphatic drainage. The goal of the transplant is to restore physiologic LN drainage and improve lymphedema. Donor LNs are commonly found in the groin, axilla, neck, omentum, or submental region. Imaging can be used for preoperative planning to identify donor sites with the richest number of LNs. This can help identify those patients who may be candidates for VLNT and can help identify the best anatomic site for surgical harvest in those candidates. Imaging can be performed with US, CT, or MRI. VLNT preoperative imaging often requires acquisition techniques and reconstruction parameters that differ from those used in routine diagnostic imaging. Furthermore, to properly identify target LNs, the radiologist must be aware of surgical anatomic landmarks. Online supplemental material is available for this article. ^©RSNA, 2020.

An economic analysis of prophylactic lymphovenous anastomosis among breast cancer patients receiving mastectomy with axillary lymph node dissection

BACKGROUND AND OBJECTIVES

Prophylactic lymphovenous anastomosis (LVA) has been shown to decrease the incidence of postoperative lymphedema among patients receiving mastectomy with axillary lymph node dissection (ALND). However, the economic impact of this intervention on overall healthcare costs has not been adequately studied and insurance reimbursement for lymphedema treatment is limited resulting in substantial out-of-pocket patient expenses.

METHODS

We performed a cost-minimization decision analysis from the societal perspective to assess two different patient scenarios: (a) mastectomy with ALND alone, (b) mastectomy with ALND and prophylactic LVA.

RESULTS

The annual cost of lymphedema-related care is estimated to be $5,691.88 ($3,160.52 direct, $2,531.36 indirect). If all patients undergoing mastectomy with ALND undergo prophylactic LVA, the average expected lifetime cost per patient in the entire population (whether or not they develop lymphedema) is approximately $6,295.61, compared to $13,942.26 if no patients in the same population receive prophylactic LVA.

CONCLUSIONS

Prophylactic LVA is economically preferred over mastectomy and ALND alone from a cost minimization perspective, and results in an average of $7,646.65 (45.2%) cost saving per patient over the course of their lifetime.

Selective recovery of vanadium as AMV from calcium vanadate sludge by direct AS leaching process: An industrial approach

Generation of calcium vanadate waste sludge their management and treatment.is one of the major problem of metal processing industry. In this paper, we have proposed a simple process for the selective recovery of vanadium as ammonium metavanadate (AMV) from the calcium vanadate sludge using ammonium sulphate (AS) as a leaching agent. Under the optimum leaching condition (pH-7.5, temperature-80 °C, time-1 h, AS reagent-0.5 M) it is possible to leach out 82% of V values from the calcium vanadate sludge. The overall recovery of V is 81% with 98.5% AMV product purity. The AMV product quality from AS leach process has been compared with conventional H₂SO₄ leach process. The proposed process has major advantages such as, better economic benefits, less chemical consumption, minimum effluent recycling and less waste generation.

Contemporary Management of Alopecia: A Systematic Review and Meta-analysis for Surgeons

BACKGROUND

The decision of surgical approach for hair restoration often involves evaluation of the type of alopecia; however, the impact of surgical hair restoration from existing techniques in specific population subsets has not been comprehensively investigated.

OBJECTIVES

The authors sought to systematically review the literature on micrografts, minigrafts, mini-micrografts, tissue grafts, tissue flaps and expanders, as well as evaluate graft survival and satisfaction within specific populations in a meta-analysis.

METHODS

PubMed and Scopus literature searches between 1980 and 2018 yielded 57 articles for systematic review and 34 articles for meta-analysis. Study design, mean patient age and gender, patient alopecia type, surgical hair restoration technique, number of treatment areas, mean follow-up, graft survival rate and satisfaction rate were extracted from each study, and a meta-analysis was performed.

RESULTS

The pooled rates of graft survival were 84.98% (95% CI 78.90-91.06) using micrografts and 93.11% (95% CI 91.93-94.29) using micrografts and minigrafts in nonscarring alopecia patients, as well as 88.66% (95% CI 80.12-97.20) using micrografts and 86.25% (95% CI 74.00-98.50) using micrografts and minigrafts in scarring alopecia patients. The pooled rates of satisfaction were 89.70% (95% CI 82.64-96.76) using micrografts and 97.00% (95% CI 92.48-100.0) using micrografts and minigrafts in nonscarring alopecia patients, as well as 97.80% (95% CI 94.59-100.0) using micrografts and 88.70% (95% CI 66.49-100.0) using micrografts and minigrafts in scarring alopecia patients. Dot plots depict rates of graft survival rate from micrografts and satisfaction from micrografts and minigrafts.

CONCLUSION

Surgical hair restoration for nonscarring and scarring alopecia yields high graft survival and satisfaction rates.

LEVEL OF EVIDENCE III

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.

Ischemia and reperfusion injury in superficial inferior epigastric artery-based vascularized lymph node flaps

Vascularized lymph node transfer (VLNT) is a promising treatment modality for lymphedema; however, how lymphatic tissue responds to ischemia has not been well defined. This study investigates the cellular changes that occur in lymph nodes in response to ischemia and reperfusion. Lymph node containing superficial epigastric artery-based groin flaps were isolated in Prox-1 EGFP rats which permits real time identification of lymphatic tissue by green fluorescence during flap dissection. Flaps were subjected to ischemia for either 1, 2, 4, or 8 hours, by temporarily occluding the vascular pedicle. Flaps were harvested after 0 hours, 24 hours, or 5 days of reperfusion. Using EGFP signal guidance, lymph nodes were isolated from the flaps and tissue morphology, cell apoptosis, and inflammatory cytokines were quantified and analyzed via histology, immunostaining, and rtPCR. There was a significant increase in collagen deposition and tissue fibrosis in lymph nodes after 4 and 8 hours of ischemia compared to 1 and 2 hours, as assessed by picrosirius red staining. Cell apoptosis significantly increased after 4 hours of ischemia in all harvest times. In tissue subject to 4 hours of ischemia, longer reperfusion periods were associated with increased rates of CD3+ and CD45+ cell apoptosis. rtPCR analysis demonstrated significantly increased expression of CXCL1/GRO-α with 2 hours of ischemia and increased PECAM-1 and TNF-α expression with 1 hour of ischemia. Significant cell death and changes in tissue morphology do not occur until after 4 hours of ischemia; however, analysis of inflammatory biomarkers suggests that ischemia reperfusion injury can occur with as little as 2 hours of ischemia.

Meningeal Lymphatics: A Review and Future Directions From a Clinical Perspective

The recent discovery of lymphatic vessels in the meningeal layers calls into question the known mechanisms of fluid and macromolecule homeostasis and immunoregulation within the central nervous system. These meningeal lymphatic vessels and their potential role in the pathophysiology of neurological disease have become a rapidly expanding area of research, with the hopes that they may provide a novel therapeutic target in the treatment of many devastating conditions. This article reviews the current state of knowledge surrounding the anatomical structure of the vessels, their functions in fluid and solute transport and immune surveillance, as well as their studied developmental biology, relationship with the novel hypothesized “glymphatic” system, and implications in neurodegenerative disease in animal models. Furthermore, this review summarizes findings from the human studies conducted thus far regarding the presence, anatomy, and drainage patterns of meningeal lymphatic vessels and discusses, from a clinical perspective, advancements in both imaging technologies and interventional methodologies used to access ultrafine peripheral lymphatic vessels.