Photoacoustic imaging, which enables high-resolution imaging in deep tissues, has lately attracted considerable attention. For tumor imaging, photoacoustic probes have been proposed to enhance the photoacoustic effect to improve detection sensitivity. Here, we evaluated the feasibility of using a biocompatible hydrophilic polymer, polyoxazoline, conjugated with indocyanine green (ICG) as a tumor-targeted photoacoustic probe via enhanced permeability and retention effect. ICG molecules were multivalently conjugated to partially hydrolyzed polyoxazoline, thereby serving as highly sensitive photoacoustic probes. Interestingly, loading multiple ICG molecules to polyoxazoline significantly enhanced photoacoustic signal intensity under the same ICG concentration. In vivo biodistribution studies using tumor bearing mice demonstrated that 5% hydrolyzed polyoxazoline (50 kDa) conjugated with ICG (ICG/polyoxazoline = 7.8), P14-ICG7.8, showed relatively high tumor accumulation (9.4%ID/g), resulting in delivery of the highest dose of ICG among the probes tested. P14-ICG7.8 enabled clear visualization of the tumor regions by photoacoustic imaging 24 h after administration; the photoacoustic signal increased in proportion with the injected dose. In addition, the signal intensity in blood vessels in the photoacoustic images did not show much change, which was attributed to the high tumor-to-blood ratios of P14-ICG7.8. These results suggest that polyoxazoline-ICG would serve as a robust probe for sensitive photoacoustic tumor imaging.
This report describes a case of a patient who underwent secondary reconstruction of the maxilla using a combined scapular osseous and thoracodorsal artery perforator (TAP) flap, in which the pedicle of the scapular osseous flap was lengthened by reconnecting the angular branch of the thoracodorsal artery to the serratus branch. The patient was a 62-year-old man who had undergone left total maxillectomy for maxillary carcinoma and came for reconstruction of left deformity. A reconstructive procedure involving a vascularized scapular osseous and TAP flap transfer was planned. However, the patient's ipsilateral superficial temporary artery and facial artery was found stenosed due to previous radiotherapy and chemotherapy and were not suitable for use as recipient vessels. Thus, a long flap pedicle was needed for anastomoses to the contralateral recipient vessels. We lengthened the pedicle of the scapular osseous flap by reconnecting the angular branch of the thoracodorsal artery to the serratus branch within the chimeric free flap and then anastomosed it to the contralateral facial vessels. The postoperative course was uneventful, and the left cheek deformity was well corrected. Using the technique of reconnection of branches within the blood supply system, a chimeric flap with a long pedicle may be elevated safely whilst avoiding the need for vein grafts.
Microsurgical procedure of free tissue transfer in critical limb ischemia patients with large ulceration has already been established. The nutrient flap concept was that transferred tissue functioned not only to cover the skin defect but also as a supplementary blood supply to the ischemic lower leg. This report showed the justification for this concept, which was rarely discussed. A 58-year-old male patient with progressive forefoot gangrene caused by arteriosclerosis obliterans was presented. The distal bypass procedure was performed as revascularization surgery, and a latissimus dorsi (LD) myocutaneous flap was transplanted to cover ulceration. The arterial pedicle of the flap was anastomosed to the vein graft in an end-to-end manner, and the venous pedicle was anastomosed to the posterior tibialis vein in an end-to-end manner. Bypass graft blood flow went straight to the LD flap only. The postoperative course was uneventful. The free flap and right foot survived successfully and the patient was ambulatory with no recurrence of ulceration wearing order-made shoes more than three years after transplantation. Vessel-selective angiography was performed two months after surgery. An angiographic catheter was inserted into the bypass graft, which ran straight through the flap nutrient artery. The results obtained showed that not only the transferred flap area, but also the remaining original foot soft tissue (including the sole and heel) was clearly visualized radiologically only through the flap nutrient vessel. This findings of the angiography appear to provide direct evidence for the nutrient flap concept.
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