Microscopic characterization of collagen modifications induced by low‐temperature diode‐laser welding of corneal tissue

Matteini, Paolo; Rossi, Francesca; Menabuoni, Luca; Pini, Roberto

doi:10.1002/lsm.20532

Cited by 45 publications

(36 citation statements)

References 53 publications

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“…The process is based on the photothermal activation of the main components of the extracellular matrix: heating of the tissue induces the formation of new bonds and interactions between adjacent molecules, stabilized upon cooling [3].…”

Section: Introductionmentioning

confidence: 99%

Laser tissue welding in ophthalmic surgery

Rossi¹,

Matteini²,

Ratto³

et al. 2008

Journal of Biophotonics

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Laser welding of ocular tissues is an alternative technique or adjunct to conventional suturing in ophthalmic surgery. It is based on the photothermal interaction of laser light with the main components of the extracellular matrix of connective tissues. The advantages of the welding procedure with respect to standard suturing and stapling are reduced operation times, lesser inflammation, faster healing and increased ability to induce tissue regeneration. The procedure we set up is based on the use of an infrared diode laser in association with the topical application of the chromophore Indocyanine Green. Laser light may be delivered either continuously or in pulses, thus identifying two different techniques that have been applied clinically in various types of transplants of the cornea.

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Section: Introductionmentioning

confidence: 99%

Laser tissue welding in ophthalmic surgery

Rossi¹,

Matteini²,

Ratto³

et al. 2008

Journal of Biophotonics

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“…Prompted by these findings, researchers at our center developed a system combining a CO 2 laser with a fiber-optic radiometer to monitor and control the temperature of the irradiated biological tissue in real time, thus preventing photothermal damage to the cornea as well as indicating the proper surface temperature for achieving the corneal seal [17,18,19]. This real-time system enables the surgeon to halt welding when the corneal surface temperature exceeds 65°C, which was previously found to be the upper limit of the surface temperature in which there is no denaturating photothermal injury to the irradiated cornea [20]. Fibers made of polycrystalline halides are used because they are highly transparent in the mid-infrared range, unlike the standard optical fibers of a Nd:YAG laser [21].…”

Section: Introductionmentioning

confidence: 99%

CO<sub>2</sub> Laser Welding of Corneal Cuts with Albumin Solder Using Radiometric Temperature Control

Strassmann

Livny²,

Loya³

et al. 2013

Ophthalmic Res

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Purpose: To examine the efficacy and reproducibility of CO₂ laser soldering of corneal cuts using real-time infrared fiber-optic radiometric control of tissue temperature in bovine eyes (in vitro) and to evaluate the duration of this procedure in rabbit eyes (in vivo). Methods: In vitro experiment: a 6-mm central perforating cut was induced in 40 fresh bovine eyes and sealed with a CO₂ laser, with or without albumin soldering, following placement of a single approximating nylon suture. A fiber-optic radiometric temperature control system for the CO₂ laser was used. Leaking pressure and histological findings were analyzed and compared between groups. In vivo experiment: following creation of a central perforation, 6 rabbit eyes were treated with a CO₂ laser with albumin solder and 6 rabbit eyes were treated with 10-0 nylon sutures. The amount of time needed for completion of the procedures was compared. Results: In vitro experiment: effective sealing was achieved by CO₂ laser soldering. Mean (± SD) leaking pressure was 109 ± 30 mm Hg in the bovine corneas treated by the laser with albumin solder compared to 51 ± 7 mm Hg in the sutured control eyes (n = 10 each; p < 0.001). Mean leaking pressures were much lower in the corneal cuts sealed only with the laser without albumin solder (48 ± 12 mm Hg) and in the cuts sealed only with albumin without laser welding (6.3 ± 4 mm Hg) than in the cuts treated with laser welding and albumin solder. In vivo experiment: mean surgical time was 140 ± 17 s in the laser-treated rabbits compared to 330 ± 30 s in the sutured controls (n = 6; p < 0.001). A histopathological study of the rabbit corneas 1 day after laser soldering revealed sealed corneal edges with a small gap bridged by coagulated albumin. The inflammatory reaction was minimal in contrast to the sutured controls. No thermal damage was detected at the wound edges. Conclusions: CO₂ laser soldering combined with the fiber-optic radiometer is an effective, reliable, and rapid tool for the closure of corneal wounds, and holds advantages over conventional suturing in terms of leaking pressure and surgical time.

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“…The first step is governed by the thermal denaturation of PGs, mainly occurring before the onset of fibrillar collagen denaturation, that is, from $45 to $60 C. In this range one or two subsequent phase transitions are observed that are correlated to a local disorder of the regular fibrillar collagen arrangement. This can probably be ascribed to the breaking of interfibrillar PGs bridges, which leads to a drastic change of the interfibrillar distances [18,19]. The next stage consists in the helix-to-coil transition of collagen molecules, which proceeds in two following steps.…”

Section: Thermal Modifications Of Connective Tissues and Mechanism Ofmentioning

confidence: 99%

“…These include traditional methods such as optical and fluorescence microscopy, which allow for an investigation at the micron scale [6,24], and transmission and scanning electron microscopy (TEM and SEM, respectively), which are useful when studying nanometric structures [19,25,26]. Other techniques recently applied for the analysis of biological material have also been tested, such as atomic force microscopy (AFM) and second-harmonic generation (SHG) microscopy, which provide complementary information [27][28][29].…”

Section: Thermal Modifications Of Connective Tissues and Mechanism Ofmentioning

confidence: 99%