Khi một khâu được gắn, các mép vết thương nên được apposed. Lý tưởng nhất, toàn cầu nên được áp lực. Hải lý khác nhau có thể được sử dụng để thực hiện mục tiêu này. Ma sát sản xuất của khâu đó có thể xác định loại nút dùng để bảo đảm các khâu. | 22 Anthony J. Johnson and R. Doyle Stuffing When a suture is tied the wound edges should be apposed. Ideally the globe should be pressurized. Various different knots may be used to accomplish this goal. -The friction produced by the suture itself may determine which type of knot is used to secure the suture. Rough threads make poor slipknots. Smooth sutures such as nylon are easily tied into slipknots see Chap. 2 . The basic principles of ophthalmic microsur-gical knot tying include 1. The suture should be tied so that the wound edges are properly approximated. 2. The first knotting loop called the approximation loop performs the actual suturing function It apposes and fixes the wound edges in the desired position. All additional loops serve only to secure the approximating loop. 3. The securing loops should be tightened at right angles to the suture plane so that they will not affect the established suture tension. 4. The approximation loop should not be tied too tightly as this will contribute to tissue distortion or strangulation. 5. Extra throws do not add strength to a properly tied knot and only contribute to its bulk. A bulky knot can be difficult to bury. 6. The holding strength of a knot depends largely on the friction created within the tightened loops hence the quality of the suture material plays an important role in knot construction a. Rough suture material favors square knots because of their high friction. b. Smooth suture materials favor slipknots because the approximating loop tends to loosen before the approximation loop is tied. 7. Attention to knot-tying technique is very important. Square knots and slipknots can be tied from the same initial loop arrangement. Only the direction of traction on the knots will determine which knot is created Fig. . 8. Care must be taken to avoid damage to the suture material when handling it. Avoid excessive manipulation of the suture with surgical instruments. Excessive handling or twisting of the suture .
