Laser Fluorescence Angiography Research Articles

Cost-effectiveness of Early Division of the Forehead Flap Pedicle.

The paramedian forehead flap is considered the gold standard procedure to optimally reconstruct major defects of the nose, but this procedure generally requires 2 stages, where the flap pedicle is divided 3 weeks following the initial surgery to ensure adequate revascularization of the flap from the surrounding recipient tissue bed, which can cost a patient time out of work or away from normal social habits. It has previously been shown that the pedicle may be safely divided after 2 weeks in select patients where revascularization from the recipient bed was confirmed using intraoperative laser fluorescence angiography to potentially save the patient time and money. To demonstrate the cost-effectiveness of takedown of the paramedian forehead flap pedicle after 2 weeks using angiography with indocyanine green (ICG). Retrospective cohort study of all patients who underwent 2-week division of the forehead flap after nasal reconstruction. Patient, tumor, defect, and outcomes data were collected. Cost-minimization analysis was performed by comparing the overall costs of 2-week takedown with angiography to a hypothetical patient undergoing 3-week takedown without angiography. Two-week division of the forehead flap after nasal reconstruction. Cost-minimization analysis performed by calculating the total variable costs for a patient in our cohort vs costs to a theoretical patient for whom angiography was not performed and the pedicle was divided at the 3-week mark. A total of 22 patients were included (mean [SD] age, 70.3 [10.0] years; 8 women [36.4%] and 14 men [63.6%]). The selection criteria for 2-week division of the pedicle are a wound bed with at least 50% vascularized tissue present, partial-thickness defects, and absence of nicotine use. All were divided at the 2-week mark with no instances of flap necrosis. One patient had a squamous eccrine carcinoma histology before reconstruction, all other patients had basal cell carcinoma, squamous cell carcinoma, and melanoma. Cost-minimization analysis showed that the use of angiography with ICG results in cost savings of $177 per patient on average. Two-week takedown of select paramedian forehead flap patients can be performed safely with verification using angiography with ICG. Although this technology inherently adds cost, it is cost-effective, saving a total of $177 per patient. NA.

Fluorescence Angiography in Colorectal Resection.

Intraoperative laser fluorescence angiography is a relatively new tool that can be used by colorectal surgeons to ensure adequate perfusion to bowel that remains after resection. It has been used mostly to determine an appropriate point of transection of the proximal bowel, as well as to ensure perfusion after the anastomosis has been constructed. We propose a different use of the technology in complex cases to ensure the ability to safely transect a major vascular pedicle and to ensure that perfusion will remain adequate. The purpose of this article is to describe a new use for fluorescence angiography technology. This is a technical note. The work was conducted at a tertiary care military medical center. Patients included individuals requiring oncologic colorectal resection where the status of 1 major vascular pedicle was unknown or impaired. We assessed perfusion after occlusion of a major vascular pedicle for the short term in hospital outcomes. Adequate studies were obtained, and perfusion was maintained in both patients. Oncologic resections were performed, and short-term outcomes were comparable with any individual undergoing these procedures. This study was limited because it is early experience that was not performed in the setting of a scientific investigation. Application of intraoperative fluorescence angiography in this setting appears to be safe and may assist the surgeon in estimating reliable vascular perfusion in patients such as these who require oncologic colorectal resection.

Comparison of Intestinal Microcirculation and Wound Healing in a Rat Model

ABSTRACTPurpose: If a colonic or small bowel lesion is not accessible for endoscopic mucosal resection, enterotomy is a possible although rarely performed surgical technique. It has never been compared to circular anastomosis regarding leakage rate, bowel wall perfusion, and wound healing. Thus, the aim of this basic experimental scientific study was to investigate perianastomotic microcirculation and wound healing. Methods: Forty rats were divided into four groups (1 jejunal anastomosis, 2 jejunal enterotomy, 3 colonic anastomosis, and 4 colonic enterotomy). Following anastomosis and enterotomy, the intestinal perfusion was measured using laser fluorescence angiography (IC-View). On postoperative day 7, the surface of the mucosal villi, expression of matrix metalloproteinases (MMP) 2, 8, 9, and 13, and the number of proliferating cells (Ki67) as well as the collagen types I/III ratio were analyzed. Results: The perianastomotic microperfusion was significantly reduced in all groups compared to the reference region. The perianastomotic perfusion index was significantly reduced in group 1 compared with group 2, whereas the perfusion index in group 3 was slightly but not significantly reduced in comparison to group 4. Ki67 was elevated in both circular anastomosis groups. Surface of the mucosal villi, MMP expression, and collagen type I/III ratio revealed no significant differences. Conclusions: Our study affirms the theoretical consideration of a better microperfusion of the bowel wall following an antimesenterial enterotomy and demonstrates that enterotomy is not inferior compared to circular anastomosis. Even though enterotomy is a rarely used surgical technique, it should be regarded as a possible alternative in particular situations.

Laser fluorescence angiography reveals perfusion defects in retrograde cardioplegia

Adequate perfusion of the right ventricle with retrograde cardioplegia has always been questioned. However, clinical studies suggested sufficient protection and, up to now, intraoperative assessment of cardioplegia distribution has been difficult. As a pilot study in 14 patients, we used indocyanine green laser fluorescence angiography (ICGLA) to assess vascular and myocardial perfusion of different areas of the right anterior ventricular wall. Regions of interest were analyzed quantitatively using a new software package. ICGLA allowed rapid and reliable visualization of cardioplegic flow and distribution. Retrograde cardioplegia revealed perfusion defects in the territory of the right anterior cardiac veins when compared to antegrade delivery and to areas close to the left anterior descending vein(s), confirmed by quantitative analyses of maximal fluorescence intensity. Five patients were excluded from quantitative analyses. The learning curve, pitfalls, limitations and special image details are described. A larger study is necessary to examine the relevance of perfusion defects to metabolic changes in affected myocytes and to global right ventricular function.

Bauchdeckenverschluss und Narbenhernienprävention - Was braucht die Chirurgie?

In the light of an incisional hernia incidence of between 10 and 20 % that remains constantly high in spite of modifications of suture materials and suture techniques, intensified scientific efforts aiming at incisional hernia prevention are -required. This article reviews the scientific results dealing with incisional hernia incidence, time of manifestation, risk factors and the influence of suture material and suture technique. A lack of evidence-based data and no current consensus concerning the ideal material and technique to close laparotomies has to be mentioned. To encourage a novel approach to incisional hernia -prevention, the results of experimental studies which demonstrate the negative effects of conventional laparotomy closure on the abdominal wall are discussed. Histology and additionally -laser-fluorescence angiography reveal the weak-en-ing of abdominal wall structures and abdominal wall perfusion after directly suturing the -incisional edges. Additionally, inadequate suture -tension has an influence on collagen quantity and quality in the healing incision. Further investigations with a suture simulator have made clear that surgical sutures vary widely in precision and reproducibility of suture tension when completed only under visual and tactile control. As suture tension dynamics cannot be measured due to the lack of adequate devices, an implantable sensor has been developed that reveals a loss of suture tension of up to 60 % of the initial tension in the first 2 hours after completion of laparotomy closure. These results have led to the development and experimental use of a bridging closure with a tension-banding technique. This technique has almost no influence on abdominal wall per-fusion, leaves the architecture and dynamics of the abdominal wall intact, and results in a favour-able ultra-structural composition of collagen and a mechanically stable laparotomy healing after 15 months. Measures to prevent incisional hernia formation - which is in fact the post-operative complication in surgery most frequently leading to re-operation - require intensified research activities. Success will only be achieved if the development of -unconventional closure techniques is encouraged and the beaten path of suturing the incisional edges is discarded.

Intraoperative laser fluorescence angiography in colorectal surgery: a noninvasive analysis to reduce the rate of anastomotic leakage

Up to 19% of all colorectal resections develop clinically apparent insufficiencies. Insufficient perfusion of the anastomosis is recognized as an important risk factor. As tissue perfusion can be objectified intraoperatively using laser fluorescence angiography (LFA), its effect on the rate of anastomotic complications was evaluated in a retrospective matched-pairs analysis. Between 2003 and 2008, all anastomosis or resection margins in colorectal cancer resections were investigated intraoperatively using LFA (LFA group). Patients with colorectal cancer resections between 1998 and 2003 without LFA served as the control group. Four hundred two patients were matched for age, T-stage, type of resection and anastomosis, defunctioning stoma, administration of blood, emergency conditions, and body mass index. Statistical analysis was performed using the Fisher and the Wilcoxon tests. Twenty-two surgical revisions were necessary due to anastomotic leakage, seven (3.5%) in the LFA group and 15 (7.5%) in the control group. Subgroup analysis revealed that in elective resections the rate of revision was 3.1% (LFA group) and 7.7% (control group) (p = 0.04, risk of revision (ROR) reduced by 60%). In patients older than 70 years, the rate of revision was 4.3% (LFA group) compared to 11.9% (control group) (p = 0.04, ROR reduced by 64%). After hand-sewn anastomosis, the rate of revision was 1.2% (LFA group) and 8.5% (control group) (p = 0.03, ROR reduced by 84%). Hospital stay was significantly reduced in the LFA group (Wilcoxon test; p = 0.01). There was an overall reduction in the absolute revision rate of 4% in the LFA group and a significantly reduced rate of revision in the subgroup analysis of patients undergoing elective colorectal resections, in patients older than 70 years and in patients with hand-sewn anastomosis. This demonstrates that LFA is a method that may significantly reduce not only the rate of severe complications in colorectal surgery but also the hospital length of stay.

In vivo perfusion analysis of normal and dysplastic ears and its implication on total auricular reconstruction

During the first stage of total auricular reconstruction with autologous rib cartilage, according to Nagata, the cartilage framework is placed in a subcutaneous pocket. Its posterior skin flap is relatively large and can be prepared with or without a subcutaneous pedicle. This represents the crucial part of the procedure, as impaired healing and infection can occur due to low perfusion. Nothing was known about the blood supply of ear remnants or flap perfusion during reconstruction. It was not clear whether the preservation of the additional subcutaneous pedicle secures high blood supply. We used laser fluorescence angiography with indocyanine green dye for anatomical and functional perfusion studies in eight normal ears. Subsequently the anatomical and functional vessel architecture of 18 dysplastic ears was investigated. Finally, five patients each were operated on with or without subcutaneous pedicle during auricular reconstruction and intraoperatively monitored with laser fluorescence angiography. We showed that the vessel structure of normal ears detected by fluorescence angiography is equivalent to anatomical preparations. The surrounding skin in high grade microtia remnants is biphasically perfused by deep perforators and by the cutaneous vessel network. The preservation of the subcutaneous pedicle during auricular reconstruction leads to significantly better perfusion of the posterior skin flap. No signs of critical perfusion or complications were observed in these patients. We present the feasibility of laser fluorescence angiography to simultaneously gain anatomical and functional data about skin blood supply. The first anatomical and functional description of blood supply of ear remnants in third grade microtia is given. Functional data of skin flap perfusion during and after complete ear reconstruction were evaluated. The present study shows that the subcutaneous pedicle of Nagata's procedure is of great importance for success of the first stage operation as it prevents impaired wound healing. In contrast, patients without a subcutaneous pedicle had a broad spectrum of reduced perfusion and therefore some had complications.