Züger B J, Ott B, Mainil-Varlet P, Schaffner T, Clémence J F, Weber H P, Frenz M
Institute of Applied Physics, University of Berne, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
Lasers Surg Med. 2001;28(5):427-34. doi: 10.1002/lsm.1070.
The surgical treatment of full-thickness cartilage defects in the knee joint remains a therapeutic challenge. Recently, new techniques for articular cartilage transplantation, such as mosaicplasty, have become available for cartilage repair. The long-term success of these techniques, however, depends not only on the chondrocyte viability but also on a lateral integration of the implant. The goal of this study was to evaluate the feasibility of cartilage welding by using albumin solder that was dye-enhanced to allow coagulation with 808-nm laser diode irradiation.
STUDY DESIGN/MATERIALS AND METHODS: Conventional histology of light microscopy was compared with a viability staining to precisely determine the extent of thermal damage after laser welding. Indocyanine green (ICG) enhanced albumin solder (25% albumin, 0.5% HA, 0.1% ICG) was used for articular cartilage welding. For coagulation, the solder was irradiated through the cartilage implant by 808-nm laser light and the tensile strength of the weld was measured.
Viability staining revealed a thermal damage of typically 500 m in depth at an irradiance of approximately 10 W/cm(2) for 8 seconds, whereas conventional histologies showed only half of the extent found by the viability test. Heat-bath investigations revealed a threshold temperature of minimum 54 degrees C for thermal damage of chondrocytes. Efficient cartilage bonding was obtained by using bovine albumin solder as adhesive. Maximum tensile strength of more than 10 N/cm(2) was achieved.
Viability tests revealed that the thermal damage is much greater (up to twice) than expected after light microscopic characterization. This study shows the feasibility to strongly laser weld cartilage on cartilage by use of a dye-enhanced albumin solder. Possibilities to reduce the range of damage are suggested.
膝关节全层软骨缺损的手术治疗仍是一项治疗挑战。近来，诸如镶嵌成形术等关节软骨移植新技术已可用于软骨修复。然而，这些技术的长期成功不仅取决于软骨细胞的活力，还取决于植入物的横向整合。本研究的目的是评估使用经染料增强的白蛋白焊料通过808纳米激光二极管照射进行凝血从而实现软骨焊接的可行性。
研究设计/材料与方法：将传统的光学显微镜组织学与活力染色进行比较，以精确确定激光焊接后热损伤的程度。吲哚菁绿（ICG）增强的白蛋白焊料（25%白蛋白、0.5%透明质酸、0.1%ICG）用于关节软骨焊接。为进行凝血，通过808纳米激光照射软骨植入物上的焊料，并测量焊接处的拉伸强度。
活力染色显示，在约10瓦/平方厘米的辐照度下照射8秒时，热损伤深度通常为500微米，而传统组织学显示的损伤程度仅为活力测试结果的一半。热浴研究表明，软骨细胞发生热损伤的最低阈值温度为54摄氏度。使用牛白蛋白焊料作为粘合剂可实现有效的软骨粘结。实现了超过10牛/平方厘米的最大拉伸强度。
活力测试表明，热损伤比光学显微镜表征后预期的要大得多（高达两倍）。本研究表明，使用染料增强的白蛋白焊料对软骨与软骨进行强激光焊接是可行的。文中还提出了减少损伤范围的可能性。
