Bending strength
One of the essential characteristics of surgical needles is bending strength.
The needle should not become twisted when passing through the tissues. If it does, this could damage the wound and the surrounding tissues.
Control of the needle‘s trajectory when it is passing through the body tissues depends on the capacity of the needle to conserve its original characteristics see Ductility >>.
Body
Along with the point see Point >>, the body is the other part of a needle. It can have different shapes (triangular, round, etc.) each of which serves for a particular use.
The body of the needle is the part that is held in the needle-holder according to the 1/3 - 2/3 rule for a good, stable grip. [3]
There are a large number of curvature/body/point combinations to cover all tissue and surgery requirements.
Each type of needle body has a corresponding letter and symbol.
Braided
Sutures can be made from a single filament see Monofilament >> or from several filaments (multifilament) which are braided or twisted.
Compared to monofilament sutures, braided ones have a greater risk of promoting infection due to capillarity, as the interstices between the fibres can facilitate the spread of pathogens along the fibre and thus direct to the placement site.
Braided sutures have a relatively rough surface which causes a «saw effect» when the thread passes through the tissues. [4]
Properties of braided sutures and monofilament sutures
| Braided | Monofilament | |
| Strength | + | + |
| Tolerance | +/- | + |
| Capillarity | + | - |
| Glide | +/- | + |
| Flexibility | + | - (memory) |
| Elasticity | - | - |
| Knot fixation | + | - |
Nevertheless, braided sutures are widely used in practice.
In the B. Braun range, Novosyn®, Safil®, Safil® Quik and Premicron® are very widely used braided sutures.
[3] M. S. Khan, S. D. Bann, A. Darzi, and P. E. M. Butler; Suturing: a lost art; Ann R Coll Surg Engl. 2002 July; 84(4): 278-279.
[4] M Leclercq; Fils et aiguilles ; Prof P. Erpicum 2008-2009.