Warm ischemia (WI) and bleeding during laparoscopic partial nephrectomy (LPN) place technical constraints on surgeons. Our aim was to develop a safe and effective laser-assisted LPN-technique without the need for WI. In this study, a diode laser-emitting light at a wavelength of 1,318 nm at output powers between 45 and 70 W in continuous-wave mode was used. Light was coupled into a flexible 600-μm bare fiber to be transported to the tissues. After dry lab experience, 13 patients (six males, seven females) underwent five open and eight laparoscopic/retroperitoneoscopic partial nephrectomies. Postoperative renal function and serum C-reactive protein (CRP) were monitored and coagulation depth and effects on resection margins (RR) were evaluated. Demographic, clinical, and follow-up data are presented. Mean operative time was 116.5 min (range 60-175 min) with mean blood loss of 238 ml (range 50-600 ml). Laser light application took a maximum of 17 min. All patients had a favorable outcome. The locations of the treated tumors (eight left and five right) were central (two), upper pole (two), lower pole (three) and middle kidney parenchyma (six anterior, two posterior, and five peripheral). Mean tumor size was 3.3 cm (range 1.8-5 cm). Two WI (19 and 24 min) were needed. Immediate postoperative serum creatinine and CRP were elevated within 0.1 to 0.6 mg/dl (mean 0.18) and 2.1-10 mg/dl (mean 6.24), respectively. Coagulation depth ranged from <1 to 2 mm without an effect on histopathological evaluation of tumors or RR. One patient had positive RR. During follow-up (2-6 months), one patient developed an A-V fistula that needed embolization. This prospective in-vivo feasibility study showed that the diode laser is a safe and promising device for LPN. Its advantages are minimal gas formation, good hemostasis, and minimal parenchymal damage. Oncological safety appears to be warranted by the use of a diode laser.

Worldwide, more individuals have iron deficiency than any other health problem. Most of those affected are unaware of their lack of iron, in part because detection of iron deficiency has required a blood sample. Here we report a non-invasive method to optically measure an established indicator of iron status, red blood cell zinc protoporphyrin, in the microcirculation of the lower lip. An optical fibre probe is used to illuminate the lip and acquire fluorescence emission spectra in ∼1 min. Dual-wavelength excitation with spectral fitting is used to distinguish the faint zinc protoporphyrin fluorescence from the much greater tissue background fluorescence, providing immediate results. In 56 women, 35 of whom were iron-deficient, the sensitivity and specificity of optical non-invasive detection of iron deficiency were 97% and 90%, respectively. This fluorescence method potentially provides a rapid, easy to use means for point-of-care screening for iron deficiency in resource-limited settings lacking laboratory infrastructure.

Laparoscopic/robotic partial nephrectomy (LPN) is increasingly considered for small renal tumors (RT). This demands new compatible surgical tools for RT-resection, such as lasers, to optimize cutting and coagulation. This work aims to characterize ex vivo handling requirements for six medically approved laser devices emitting different light wavelengths (940, 1064, 1318, 1470, 1940, and 2010 nm) amenable for LPN. Incisions were made by laser fibers driven by a computer-controlled stepping motor allowing precise linear movement with a preset velocity at a fixed fiber-tip distance to tissue. Optical parameters were measured on 200 μm tissue slices. Cutting quality depended on power output, fiber velocity and fiber-tip distance to tissue. Contact manner is suitable for cutting while a noncontact manner (5 mm distance) induces coagulation. Ablation threshold differs for each wavelength. Ablation depth is proportional to power output (within limit) while axial and superficial coagulation remains mostly constant. Increased fiber velocity compromises the coagulation quality. Optical parameters of porcine kidney tissue demonstrate that renal absorption coefficient follows water absorption in the 2 μm region while for other spectral regions (900 to 1500 and 1 μm) the tissue effects are influenced by other chromophores and scattering. Tissue color changes demonstrate dependencies on irradiance, scan velocity, and wavelength. Current results clearly demonstrate that surgeons considering laser-assisted RT excisions should be aware of the mentioned technical parameters (power output, fiber velocity and fiber-tip tissue-distance) rather than wavelength only.

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Objective: Improvement of the clinical outcome of glioblastoma (GBM) patients by employment of fluorescence and photosensitization on the basis of 5-aminolevulinic acid (5-ALA) induced protoporphyrin IX (PpIX). Methods:In this report the focus is laid on the use of tumor selective PpIX fluorescence for stereotactic biopsy sampling and intra-operative treatment monitoring. In addition, our current concept for treatment planning is presented. For stereotactic interstitial photodynamic therapy (iPDT), radial diffusers were implanted into the contrast enhancing tumor volume. Spectroscopic measurements of laser light transmission and fluorescence between adjacent fibers were performed prior, during and post PDT. Results:PpIX concentrations in primary glioblastoma tissue show high intra-and inter-patient variability, but are usually sufficient for an effective PDT. During individual treatment attempts with 5-ALA based GBM-iPDT, transmission and fluorescence measurements between radial diffusers gave the following results: 1. In some cases, transmission after PDT is considerably reduced compared to the value before PDT, which may be attributable to a depletion of oxygenated hemoglobin and/or diffuse bleeding. 2. PpIX fluorescence is efficiently photobleached during PDT in all cases.Conclusion: iPDT with assessment of PpIX fluorescence and photobleaching is a promising treatment option. Individualization of treatment parameters appears to bear a potential to further improve clinical outcomes.