09.04 Suturing Techniques - Continuous Sutures
Inserting each suture correctly is the key to good wound closure. Here you will learn how to place a suture and how to avoid damage to the wound edges.
You should be familiar with how to use the needle holder and suture needle to insert a suture with minimal tissue damage.
This module covers simple interrupted, continuous, subcuticular, mattress and pulley sutures and has plenty of tips on how to overcome common problems.
In this module
09.04 Continuous Sutures
Continuous, also known as running, sutures are made by passing the needle from side to side across the wound multiple times before finally tying the suture.
Although it will not always be possible, it is advisable to have an assistant to help you if you are using this method of suturing, in order to maintain the tension on the suture.
09.04.01 Principles Video 1
The first suture is inserted in exactly the same way as an interrupted suture, at right angles to the skin edge, and tied using a standard reef knot. Then the short end is cut. If you have an assistant, the long end of the suture is passed to them at this point. Their role is to follow, keeping the tension even and holding the trailing suture out of the way.
The distance between sutures should be exactly as for interrupted sutures (between 3 and 5mm). Work along the wound, making sure to maintain equal distance and tension between sutures, but varying the width of each stitch to prevent the fascia tearing along the line of the fibres.
After the final suture has been inserted, one loop is left long and tied off using a hand tied Aberdeen knot. The index finger and thumb of one hand display the loop, then grasp and pull through the free suture end. This forms a new loop and the old one is tightened and eliminated. Once the knot has been tied, the suture material can be cut.
09.04.02 Principles Video 2
Continuous sutures are appropriate for long wounds where wound tension has been minimized with properly placed deep sutures and where approximation of the wound edges is good.
Continuous sutures are also indicated to quickly control bleeding in the absence of other bleeding control measures, for example with a profusely bleeding scalp wound.
Theoretically, less scarring occurs with continuous sutures compared with interrupted because the sutures are placed again and again without tying each individual one. However, although there are fewer knots, the number of needle insertions remains the same.
Continuous closure is quicker to perform than interrupted and can lead to more rapid re-alignment of wound edges.
Disadvantages include possible cross-hatched scarring if the sutures are pulled too tight, difficulty in making fine adjustments along the suture line, and puckering of the suture line when the stitches are placed in thin skin.
09.04.03 Principles Video 3
For continuous sutures, your suture length should be a minimum of four times that of the incision so that you are able to complete the closure without using excessive tension.
If you are using monofilament sutures, which can be springy due to their inherent memory, there is a risk that you will experience slippage when tying the loop and suture end together to complete the suture line - even when using an Aberdeen knot. A more secure technique when using monofilament sutures is to start a continuous suture at each end of the wound and then tie the two ends together in the middle with a standard knot. An example of when you might use this technique would be closure of the abdominal wall musculature.
09.04.04 Continuous Sutures Practise
Begin by inserting a standard interrupted suture. Tie off using a standard reef knot, but trim off the short end only, leaving a length of approximately 0.5cm. Pick up the long end with your needle holder ready to insert the next suture.
Insert a second suture in exactly the same way as the first and pull the thread through. Continue to work along the wound edge in this way, maintaining a distance of 3-5 mm between each suture and keeping moderate tension at all times to prevent weak areas in the closure. Vary the width of each stitch to minimise the risk of the fascia tearing along the line of the fibres.
When you insert the last suture, don't pull the thread all the way through but leave a loop ready to tie an Aberdeen knot.
Display the loop between your right index finger and thumb and hold the free end of the suture with your left index finger and thumb.
Use your right index finger and thumb to grasp the free end through the loop. Pull it through and form a new loop, keeping the free end in your left hand so that the old loop is flattened and eliminated.
Repeat this process until you have completed four throws. Finally pass the free end through the loop, tighten down and then cut the suture thread to complete your Aberdeen knot.
09.04.04.01 Alternative Techniques for Monofilament Sutures
This technique will minimise the risk of slippage if you are using monofilament sutures which can be very springy.
Place your first suture at one end of the wound, tying with a surgeon's knot but trimming off the short end only. Continue with equally spaced continuous sutures, varying the width of each stitch to minimise the risk of the fascia tearing along the line of the fibres. Stop when you reach the midpoint of the wound.
Now take another suture and repeat this process starting at the other end of the wound. Place equally spaced continuous until you reach the midpoint again. Cut one of the suture ends leaving enough length to form the short end of your tie. Now tie the two sutures together using a surgeon's knot.
09.04.05 Things To Avoid
The next videos we will show examples of common problems with continuous closure, together with suggestions for solving them.
09.04.05.01 Too Much Tension Video 1
Pulling the suture and tying too tightly, as shown here, will produce excessive tension and a “purse-string” effect. Tissues may swell in the first few hours after surgery, tightening the suture line even further.
You should aim to approximate the wound edges comfortably, and no more.
09.04.05.02 Too Much Tension Video 2
With a wider wound where there is significant tension pulling the wound edges apart, you may find it difficult to close the wound using continuous sutures, as shown here. Even with a double throw on the first knot, the knot fails to bed down and a triple throw is necessary to achieve this. This is an early indication that the closure may fail. As the closure progresses, it becomes more evident that the edges can only be approximated if the suture is pulled through too tightly. The finished result is an ugly, purse string effect with a gap in the closure.
In cases like this where tension is too great, use interrupted sutures instead to close the wound and progressive halving to help distribute the tension equally across the wound.
09.04.05.03 Too Little Suture Material
Make sure your suture length is adequate. Using too short a suture can be the reason why you have too much tension and will result in gathering or puckering of the wound.
The suture length should be a minimum of four times that of the incision.
09.04.05.04 Slippage with Monofilament Sutures
When completing a continuous suture line, you finish with a loop and an end to tie together. When using springy monofilament sutures there is danger of slippage, even when using an Aberdeen knot. A more secure technique is to start a continuous suture at each end of the wound and then tie the two ends together in the middle with a standard knot.
09.04.05.05 Too Fine a Suture
Too fine a suture will provide inadequate friction to hold the wound together and the edges will gape.
You will generally use sizes in the middle range: 3-0 to 5-0. On areas where cosmetic concerns are not of the utmost importance, 3-0 or 4-0 sutures are best, because the larger size makes the technique easier and the thicker sutures are stronger.