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Laser tissue welding (LTW) is a method of fusing incised tissues together. LTW has the potential to revolutionize plastic surgery and wound healing techniques by its ability to produce watertight, scarless seals with minimal foreign body reaction. While using thermal mechanisms to achieve LTW, energy from the incident laser is absorbed by water in the tissue. As the water temperature increases, partial denaturing of the collagen triple helix briefly occurs, which is quickly followed by renaturation of collagen as the tissue cools, thus providing a watertight seal. This research study investigates the efficacy of direct collagen excitation at 1,720 nm to accomplish LTW. This wavelength falls within the near-infrared (NIR) optical window III. The tensile strengths of pig skin that have been welded with NIR continuous-wave (CW) diode lasers at 1,455 nm, which promote thermal mechanisms of tissue welding, and 1,720 nm wavelengths, are compared. Near-infrared lasers tuned to 1,455 and 1,720 nm were used to weld incised pieces of porcine skin together without extrinsic solders or dyes. The tensile force of the welded tissues was measured using a digital force gauge. The average tensile force of the welded pig skin using the 1,720 nm laser was approximately four times greater than that using the CW 1,455 nm laser, suggesting that LTW accomplished through direct collagen excitation in the NIR optical window III provides greater tensile strengths.

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BACKGROUND AND AIMS: Buccal mucosa harvest for substitution urethroplasty can be painful, and may be associated with long-term complications such as perioral numbness, persistent difficulty with mouth opening, and change in salivary function. This study was designed to evaluate the efficacy of infraorbital nerve block (IOB) in relieving postoperative pain at the donor site of the buccal mucosal graft (BMG) and its associated morbidity at 30 days. MATERIAL AND METHODS: Thirty adults scheduled for BMG urethroplasty were enrolled in this study and were randomized to receive either no block group I (control) and IOB group II intraorally with 1 mL of 0.5% bupivacaine. Pain was assessed by visual analog scale, intraoral morbidity, and patient satisfaction in the immediate postoperative period. All patients were reviewed after 1 month for morbidity such as perioral numbness, pain on mastication, and tightness on mouth opening. Statistical analysis was done using Mann-Whitney's U and Chi-square tests. RESULTS: Median time to pain-free oral intake for liquids (group I: 2-5 days, group II: 1 day, P < 0.001) and solids (group I: 4 days, group II: 2 days, P < 0.001) was earlier in group II. At the follow-up after 1 month, one patient in group II and three patients in group I showed perioral numbness (P = 0.026), and five patients had pain on mastication in group I (P = 0.016). CONCLUSION: IOB is associated with postoperative analgesia and facilitation of early food intake, mitigating the morbidity of the donor site and provides satisfaction.

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BACKGROUND AND AIMS: Intercostal nerve blockade (ICNB) and peritubal infiltration of the nephrostomy tract are well-established regional anaesthetic techniques for alleviating pain after percutaneous nephrolithotomy (PCNL). This prospective study compared the efficacy of ICNB and peritubal local anaesthetic infiltration of the nephrostomy tract in providing post-operative analgesia following PCNL. METHODS: Sixty American Society of Anesthesiologist physical status 1 and II patients scheduled for PCNL requiring nephrostomy tube were randomised to receive either peritubal infiltration or ICNB. At the completion of the procedure, patients in Group P received peritubal infiltration and those in Group I received ICNB at 10, 11, 12th spaces using fluoroscopy guidance. Postoperatively, patients were followed for 24 h for pain using Visual Analogue Scale (VAS) and Dynamic VAS. Rescue analgesia was inj. tramadol 1 mg/kg IV when pain score exceeded 4. Time to first rescue analgesia, number of doses and patient's satisfaction were noted in all patients. RESULTS: Pain scores were lower in the group I at all points of measurement than group P. The mean time to first demand for rescue analgesia was higher in Group I (13.22 ± 4.076 h vs 7.167 ± 3.92 h P - 0.001). The number of demands and the amount of analgesics consumed were less in Group I. CONCLUSION: ICNB provided superior analgesia as evidenced by longer time to first demand of analgesic, reduced number of demands and consumption of rescue analgesic. Peritubal infiltration, although less efficacious, may be a safe and simple alternative technique.

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Femtosecond (fs) pulse lasers in the near-infrared (NIR) range exhibit very distinct properties upon their interaction with biomolecules compared to the corresponding continuous wave (CW) lasers. Ultrafast NIR laser tissue bonding (LTB) was used to fuse edges of two opposing animal tissue segments in vivo using fs laser photoexcitation of the native vibrations of chomophores. The fusion of the incised tissues was achieved in vivo at the molecular level as the result of the energy­matter interactions of NIR laser radiation with water and the structural proteins like collagen in the target tissues. Nonthermal vibrational excitation from the fs laser absorption by water and collagen induced the formation of cross-links between tissue proteins on either sides of the weld line resulting in tissue bonding. No extrinsic agents were used to facilitate tissue bonding in the fs LTB. These studies were pursued for the understanding and evaluation of the role of ultrafast NIR fs laser radiation in the LTB and consequent wound healing. The fs LTB can be used for difficult to suture structures such as blood vessels, nerves, gallbladder, liver, intestines, and other viscera. Ultrafast NIR LTB yields promising outcomes and benefits in terms of wound closure and wound healing under optimal conditions.

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Near infrared (NIR) continuous wave laser radiation at the 1,450 nm wavelength was used to weld porcine aorta and skin samples via the absorption of combitional vibrational modes of native water in the tissues. The fluorescence spectra were measured from the key native molecules of welded and non-welded tissues at specific excitation and emission wavelengths from collagen, elastin, and tryptophan. The changes in the fluorescence intensities and differences in Stokes shift (Δν(ss) ) of key native fluorophores were measured to differentiate the Huang-Rhys parameter values (S) of the chromophores. The strength of coupling depends on the local electron-vibration intra-tissue molecular environment and the amount of polar solvent water surrounding the net charges on collagen, elastin, and tryptophan. The S values for both non-welded and welded tissues were almost the same and less than 3, suggesting minimal changes in the local molecular environment as a result of welding.

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BACKGROUND: Laser tissue welding (LTW) is a novel method of surgical wound closure by the use of laser radiation to induce fusion of the biological tissues. Molecular dynamics associated with LTW is a result of thermal and non-thermal mechanisms. OBJECTIVES: This research focuses exclusively on better heat management to reduce thermal damage of tissues in LTW using a near infrared laser radiation. METHODS: An infrared continuous-wave (CW) laser radiation at 1,450 nm wavelength corresponding to the absorption band from combination vibrational modes of water is used to weld together ex vivo porcine aorta. RESULTS: In these studies we measured the optimal laser power and scan speed, for better tensile strength of the weld and lesser tissue dehydration. Significant amount of water loss from the welded tissue results in cellular death and tissue buckling. Various thermally conductive optical cover windows were used as heat sinks to reduce thermal effects during LTW for the dissipation of the heat. The optimal use of the method prevents tissue buckling and minimizes the water loss. Diamond, sapphire, BK7, fused silica, and IR quartz transparent optical cover windows were tested. CONCLUSIONS: The data from this study suggests that IR-quartz as the material with optimal thermal conductivity is ideal for laser welding of the porcine aorta.

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BACKGROUND: Buccal mucosal graft (BMG) substitution urethroplasty has become popular in the management of intractable anterior urethral strictures with good results. Excellent long-term results have been reported by both dorsal and ventral onlay techniques. Asopa reported a successful technique for dorsal placement of BMG in long anterior urethral strictures through a ventral sagittal approach. OBJECTIVE: To evaluate prospectively the results and advantages of dorsal BMG urethroplasty for recurrent anterior urethral strictures by a ventral sagittal urethrotomy approach (Asopa technique). DESIGN, SETTING, AND PARTICIPANTS: From December 2002 to December 2007, a total of 58 men underwent dorsal BMG urethroplasty by a ventral sagittal urethrotomy approach for recurrent urethral strictures. Forty-five of these patients with a follow-up period of 12-60 mo were prospectively evaluated, and the results were analysed. INTERVENTION: The urethra was split twice at the site of the stricture both ventrally and dorsally without mobilising it from its bed, and the buccal mucosal graft was secured in the dorsal urethral defect. The urethra was then retubularised in one stage. RESULTS AND LIMITATIONS: The overall results were good (87%), with a mean follow-up period of 42 mo. Seven patients developed minor wound infection, and five patients developed fistulae. There were six recurrences (6:45, 13%) during the follow-up period of 12-60 mo. Two patients with a panurethral stricture and four with bulbar or penobulbar strictures developed recurrences and were managed by optical urethrotomy and self-dilatation. The medium-term results were as good as those reported with the dorsal urethrotomy approach. Long-term results from this and other series are awaited. More randomised trials and meta-analyses are needed to establish this technique as a procedure of choice in future. CONCLUSIONS: The ventral sagittal urethrotomy approach is easier to perform than the dorsal urethrotomy approach, has good results, and is especially useful in long anterior urethral strictures.

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Chromium supplements are widely used as an alternative remedy for type 2 diabetes mellitus (T2DM). In vitro study findings show that chromium picolinate (CrPic) may improve insulin sensitivity by enhancing intracellular insulin receptor. In this study, we evaluated the metabolic effects of CrPic in a rat model of T2DM. Male Sprague-Dawley rats (n = 45, 8 weeks old) were divided into 3 groups. The controls (group I) received a standard diet (12% of calories as fat); group II received a high-fat diet (HFD; 40% of calories as fat) for 2 weeks and then were intraperitoneally injected with streptozotocin (STZ, 40 mg/kg; HFD/STZ) on day 14; group III rats were given group II diets with the addition of 80 microg CrPic per kilogram body weight per day. The addition of CrPic in the group III treatment lowered glucose by an average of 63% (P < .001), total cholesterol by 9.7% (P < .001), and triglycerides by 6.6% (P < .001) compared with group II treatment. Compared with group II, CrPic treatment also lowered free fatty acid levels by 24% (P < .001), blood urea by 33% (P < .05), and creatinine level by 25% (P < .01), and reduced the severity of glomerular sclerosis (P < .0001). Histopathologic findings suggest that the CrPic-treated group had normal renal tubular appearance compared with the HFD/STZ-treated group. Normal appearance of hepatocytes was observed in the CrPic-treated group. These results showed that CrPic has marked beneficial effects against microvascular complications. In conclusion, HFD/STZ rats provide a novel animal model for T2DM. Further treatment with CrPic for 10 weeks significantly ameliorated changes in metabolic risk factors including favorable changes in histopathology of the liver, kidney, and pancreas, suggesting its potential role in the management of diabetes.

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Fluorescence and phosphorescence measurements are performed on normal and malignant ex vivo human breast tissues using UV LED and xenon lamp excitation. Tryptophan (trp) phosphorescence intensity is higher in both normal glandular and adipose tissue when compared to malignant tissue. An algorithm based on the ratio of trp fluorescence intensity at 345 nm to phosphorescence intensity at 500 nm is successfully used to separate normal from malignant tissue types. Normal specimens consistently exhibited a low I(345)I(500) ratio (<10), while for malignant specimens, the I(345)I(500) ratio is consistently high (>15). The ratio analysis correlates well with histopathology. Intensity ratio maps with a spatial resolution of 0.5 mm are generated in which local regions of malignancy could be identified.

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