Preputial pedicle flap ICG blood flow assessment during proximal hypospadias repair: Development of a standardized protocol.

INTRODUCTION: Blood supply to preputial flap drives outcomes of hypospadias repair. Unfortunately, we only have surgeon's subjective assessment to evaluate flap perfusion which may not be accurate. Indocyanine green (ICG) has been used in a multitude of surgeries for perfusion assessment, however, no standardized protocol has been described for use of ICG in hypospadias repairs. The aim of this study is to develop a standardized protocol of ICG use in proximal hypospadias and establish perfusion patterns of preputial flaps. STUDY DESIGN: A pilot study was conducted using ICG in patients with proximal hypospadias undergoing first stage repair with a preputial flap. The Stryker SPY PHI system and novel quantification software, SPY-QP, were used for ICG imaging. An adaptive approach was taken to develop and implement a standardized protocol (Summary Figure). Per the protocol, ICG was administered at 3 time points which were felt to be critical for assessment of flap perfusion. Of the study patients who have undergone second stage repair, ICG was also used to reassess the flap prior to tubularization of the urethra. RESULTS: A total of 14 patients underwent first stage hypospadias repair with preputial flaps and intraoperative use of ICG. Median ICG uptake of the prepuce after degloving (dose 1) was 58.5% (IQR 43-76). ICG uptake decreased after flap harvest and mobilization (dose 2) with a median ICG uptake of 34% (IQR 26-46). ICG uptake remained stable after securing the flap in place and closing the skin (dose 3) with a median ICG uptake of 34% (IQR 25-48). ICG was able to delineate subtle findings in the preputial flaps not visible to the naked eye and in one case impacted intraoperative decision making. To date, 5 patients have undergone second stage repair. Flap assessment prior to tubularization of the urethra showed hypervascularity with a median ICG uptake of 159%. CONCLUSIONS: A standardized protocol for ICG use in proximal hypospadias was successfully developed and implemented. ICG uptake in the preputial flap decreased with increasing manipulation and mobilization of the flap. ICG was able to detect changes to flap perfusion which were not able to be seen with the naked eye. Reliance on surgeon's subjective assessment of flap perfusion may be inadequate and ICG could provide a useful tool for surgeons to improve preputial flap outcomes. ICG may also enhance the learning experience for trainees and early career urologists in these complex surgeries.

An overview of current assessment techniques for evaluating cutaneous perfusion in reconstructive surgery.

This article provides a comprehensive analysis of modern techniques used in the assessment of cutaneous flaps in reconstructive surgery. It emphasizes the importance of preoperative planning and intra- and perioperative assessment of flap perfusion to ensure successful outcomes. Despite technological advancements, direct clinical assessment remains the gold standard. We categorized assessment techniques into non-invasive and invasive modalities, discussing their strengths and weaknesses. Non-invasive methods, such as acoustic Doppler sonography, near-infrared spectroscopy, hyperspectral imaging thermal imaging, and remote-photoplethysmography, offer accessibility and safety but may sacrifice specificity. Invasive techniques, including contrast-enhanced ultrasound, computed tomography angiography, near-infrared fluorescence angiography with indocyanine green, and implantable Doppler probe, provide high accuracy but introduce additional risks. We emphasize the need for a tailored decision-making process based on specific clinical scenarios, patient characteristics, procedural requirements, and surgeon expertise. It also discusses potential future advancements in flap assessment, including the integration of artificial intelligence and emerging technologies.

Lateral Femoral Trochlea Flap Reconstruction of the Proximal Capitate: An Assessment of Congruity and Description of Technique.

PURPOSE: We examined morphologic similarities of the medial lateral femoral trochlea (MFT) and lateral femoral trochlea (LFT) osteochondral flaps for reconstruction of the proximal capitate. METHODS: Magnetic resonance imaging scans of the wrists and ipsilateral knees of 10 young healthy volunteers were obtained. Three morphologic parameters were investigated, comparing the MFT and LFT harvest sites to the capitate proximal pole. The correspondingly relevant surgical planes were compared. The coronal plane radius of curvature (ROC) of the capitate was compared with the sagittal planes of the MFT and LFT. The sagittal plane ROC of the capitate was compared to the axial planes of the MFT and LFT. The angular relationship between the dorsal cortical surface of the capitate and the proximal pole cartilage (proximal dorsal capitate pitch) was compared to the corresponding angles between the cortical bone and convex cartilage on the LFT and MFT. RESULTS: The average ratios of ROC for the coronal planes of the capitate to the MFT (0.61) and LFT (0.58) were similar. The average ratios of ROC for the sagittal planes of the capitate to the MFT (0.57) and LFT (0.86) were also similar. The proximal dorsal capitate pitch demonstrated greater similarity to the corresponding shape of the LFT (angular ratio, 1.01) than to that of the MFT (angular ratio, 0.74). CONCLUSIONS: The LFT and MFT demonstrate similar congruity to the proximal capitate in the sagittal and coronal planes of the wrist. The LFT dorsal pitch closely approximates the relationship of the proximal capitate pole to its dorsal cortical surface. CLINICAL RELEVANCE: In capitate fracture, fracture nonunion, or avascular necrosis, both the MFT and LFT demonstrate similarity to the proximal convex capitate morphology. The relationship between the cortical and chondral surfaces of the LFT is morphologically very similar to that of the proximal capitate.

Assessment of Flap Viability for Complex Transmetatarsal Amputation Using Indocyanine Green Fluorescent Angiography: A Case Study.

Despite advancements in the treatment of diabetic patients with "at-risk" limbs, minor and major amputations remain commonplace. The diabetic population is especially prone to surgical complications from lower extremity amputation because of comorbidities such as renal disease, hypertension, hyperlipidemia, microvascular and macrovascular disease, and peripheral neuropathy. Complication occurrence may result in increases in hospital stay duration, unplanned readmission rate, mortality rate, number of operations, and incidence of infection. Skin flap necrosis and wound healing delay secondary to inadequate perfusion of soft tissues continues to result in significant morbidity, mortality, and cost to individuals and the health-care system. Intraoperative indocyanine green fluorescent angiography for the assessment of tissue perfusion may be used to assess tissue perfusion in this patient population to minimize complications associated with amputations. This technology provides real-time functional assessment of the macrovascular and microvascular systems in addition to arterial and venous flow to and from the flap soft tissues. This case study explores the use of indocyanine green fluorescent angiography for the treatment of a diabetic patient with a large dorsal and plantar soft-tissue deficit and need for transmetatarsal amputation with nontraditional rotational flap coverage. The authors theorize that the use of indocyanine green may decrease postoperative complications and cost to the health-care system through fewer readmissions and fewer procedures.

Blood Perfusion of Random Skin Flaps in Humans-In Vivo Assessment by Laser Speckle Contrast Imaging.

BACKGROUND: The viability of random skin flaps (RSFs) depends on an adequate perfusion pressure to avoid necrosis. Laser speckle contrast imaging is a new method to monitor skin flap microcirculation. OBJECTIVE: The authors aimed to use laser speckle contrast imaging in evaluating the correlation between the perfusion pressure and the length-to-width ratio (LTWR) of RSFs. MATERIALS AND METHODS: Sixty patients submitted to flaps were included: 20 advancement, 20 rotation, and 20 transposition flaps. Laser speckle contrast imaging measurements of perfusion were obtained-after the flaps were planned, dissected, and sutured-from the base to the tip of the flaps, allowing the creation of plot charts and calculation of linear regression equations. RESULTS: Perfusion consistently and significantly decreased with the dissection of all flaps. A significant correlation between LTWR and perfusion was observed in undermined and sutured stages; a mathematical model was then delineated, explaining objectively the drop of perfusion along LTWR, with statistical significance, in all flaps. CONCLUSION: Laser speckle contrast imaging allows accurate, rapid, reproducible, and noncontact measurements of skin blood perfusion over RSF, ultimately leading to an optimization of skin flap planning. This study proves that variation of perfusion pressure along the flap is dependent on the LTWR in a linear decreasing function.

Quantifying the Effect of Topical Nitroglycerin on Random Pattern Flap Perfusion in a Rodent Model: An Application of the ViOptix Intra.Ox for Dynamic Flap Perfusion Assessment and Salvage.

BACKGROUND: Near-infrared spectroscopy can detect changes in tissue oxygenation postoperatively that predict flap necrosis. The authors hypothesized that this technology can be applied along with topical nitroglycerin to measure an improvement in tissue oxygenation that correlates with tissue salvage. METHODS: Dorsal, random pattern flaps measuring 10 × 3 cm were raised using Sprague-Dawley rats. Tissue oxygenation was measured after flap elevation in 10 locations using the ViOptix Intra.Ox. Animals were divided into three groups that received 30 mg of topical nitroglycerin daily, twice-daily, or not at all. Oxygenation measurements were repeated on postoperative day 1 and animals were euthanized on day 7 and evaluated for tissue necrosis. RESULTS: Tissue necrosis was greatest in controls (51.3 mm) compared to daily (28.8 mm) and twice-daily nitroglycerin (18.8 mm; p = 0.035). Three flap perfusion zones were identified: healthy (proximal, 50 mm), necrotic (distal, 20 mm), and watershed. Immediate postoperative tissue oxygenation was highest in healthy tissue (57.2 percent) and decreased to 33.0 and 19.3 percent in the watershed and necrotic zones, respectively (p < 0.001). One day after treatment with nitroglycerin, oxygenation in the healthy zone did not increase significantly (mean difference, -1.5 percent). The watershed (17.8 percent; p < 0.001) and necrotic zones (16.3 percent; p <0.001) did exhibit significant improvements that were greater than those measured in control tissues (7.9 percent; both p < 0.001). CONCLUSIONS: Serial perfusion assessment using the ViOptix Intra.Ox measured a significant improvement in flap oxygenation after treatment with topical nitroglycerin. Within the watershed area of the flap, this increase in tissue oxygenation was associated with the salvage of ischemic tissue.

Which is the Pivotal Vessel in Vascular Supercharging? An Assessment of Three Forms of Vascular Supercharging Models Using Indocyanine Green Fluorescence Angiography.

BACKGROUND: The study aimed to perform continuous and dynamic observation on the blood flow changes in a rat abdominal model of supercharged flaps to examine the roles of arterial and venous supercharging in preventing distal flap necrosis. MATERIALS AND METHODS: Eighteen rats were divided into three experimental groups. The left-sided flaps in all groups were used as controls such that the subxiphoid perforator vessels served as the only pedicle. Experimental groups I, II, and III consisted of supercharged right-sided flaps. Group I, the arteriovenous supercharging group, had flaps supercharged by the suprapubic perforator arteries and veins. Group II, the arterial supercharging group, had flaps supercharged by the suprapubic perforator arteries. Group III, the venous supercharging group, had flaps supercharged by the suprapubic perforator veins. Laser-induced near-infrared fluorescence angiography was performed before and after surgery. RESULTS: As revealed by near-infrared fluorescence angiography, the control group and venous supercharging group exhibited rapid reductions in blood supply and loss of arterial perfusion in distal areas. The distal flap necrosis was much smaller in the venous supercharging group than in the control group. Both the arteriovenous supercharging group and the arterial supercharging group exhibited adequate perfusion and resulted in full postoperative survival of the flaps. CONCLUSIONS: These findings indicated that the distal arterial hypoperfusion is the major cause of the distal venous stasis and necrosis in the flaps. Sufficient arterial supercharging ensures the distal arterial perfusion and therefore diminishes the occurrence of distal flap necrosis.

Pilot study to assess the use of a fluorescence imaging system for assessment of amputation healing.

OBJECTIVE:: The purpose of this study was to use a fluorescence imaging system (FIS) (SPYElite, NOVADAQ, US) during lower extremity amputations and develop parameters to predict amputation healing, for which there are no proven, objective tests. We hypothesised that the FIS may identify areas of poor perfusion at the time of amputation and predict potential healing complications. There are no studies involving the FIS used in this study in lower extremity amputation. METHOD:: This prospective cohort study involved patients requiring either below- or above-knee-amputation at one, mid-western medical centre. The FIS was used as per manufacturer's instructions after wound closure and before dressing. Procedure and operative management was unchanged. Through the FIS, perfusion values were plotted along the amputation site to visualise and quantify intraoperative perfusion and to compare with 30-day postoperative amputation healing. RESULTS:: Surgeons determined that all of the 18 participants had adequate perfusion at surgical wound closure. At 30 days, two subjects had wound dehiscence or infection; these correlated with low perfusion values on the FIS imaging. A further six subjects had marginal or low perfusion values, but did not develop wound failure. CONCLUSION:: It is feasible to use the FIS during amputation, however it did not perfectly predict healing course based on vascular perfusion. There were interesting patterns of poor perfusion that correlated with areas of dehiscence or infection but other patients had reduced perfusion that healed well. Due to the small sample size, no discernible perfusion value differences existed between patients who healed and patients with healing complications. A future, larger study may show that the FIS can be predictive of patient healing and aid decisions for intraoperative revision.

Intraoperative Perfusion Assessment in Mastectomy Skin Flaps: How Close are We to Preventing Complications?

BACKGROUND: Mastectomy flap necrosis is the source of considerable morbidity and cost following breast reconstruction. A great deal of effort has been put forth to predicting and even preventing its incidence intraoperatively. METHODS: A review of the literature was performed evaluating the evidence of mastectomy skin flap perfusion technologies. RESULTS: Multiple technologies have leveraged spectroscopy and/or angiography to provide real-time assessment of flap perfusion, including indocyanine green, fluorescein, and light-based devices. CONCLUSION: This manuscript endeavors to review the evidence on mastectomy skin flap perfusion analysis, highlighting the benefits, and downsides of the current technologies and identifying exciting areas of future research and development.

Donor limb assessment after vascularized groin lymph node transfer for the treatment of breast cancer-related lymphedema: Clinical and lymphoscintigraphy findings.

INTRODUCTION: Vascularized lymph node transfer is an established treatment for secondary lymphedema. Different donor sites of lymph node flap have been described. In our institute, vascularized groin lymph node (VGLN) flap is the workhorse flap for treating breast cancer-related lymphedema (BCRL). Potential complications of VGLN flap harvesting include seroma formation, thigh dysaesthesia, and iatrogenic lymphedema. METHODS: Between August 2013 and June 2016, 30 consecutive patients with a mean age of 60 years underwent VGLN transfer for BCRL. Reverse mapping of lower limb lymphatics with patent blue solution was performed in all cases. The donor limb conditions were assessed clinically with limb circumference measurement and radiologically with lymphoscintigraphy. Postoperative lymphoscintigraphy findings and transport indexes were compared between the donor and nonoperated limbs. RESULTS: The mean follow-up period was 22.11 ±â€¯7.83 months. Three (10%) patients developed groin seroma and 18 (60%) patients complained of transient thigh dysaesthesia. There was no clinically detectable donor limb lymphedema. Lymphoscintigraphy was performed at a mean of 13 months after operation. The mean transport indexes of the nonoperated limbs and donor limbs were 2.04 and 3.32, respectively. For the donor limbs, all patients had normal distribution pattern of contrast uptake. No dermal backflow pattern was demonstrated. CONCLUSION: With good knowledge of groin anatomy and meticulous surgical skills, VGLN flap can be harvested without causing major consequence to the donor limb.