An introduction to surgical techniques and practical procedures

CHAPTER 2 An introduction to surgical techniques and practical procedures



Surgical incision 15

Sutures 16

Drains 18

Stomas (-ostomies) 18

Local anaesthesia 19

Tourniquets 20

Diathermy 21

Laser 23

Laparoscopic surgery 24

Venous access 25

Central venous catheterization – internal jugular vein 26

Blood gas sampling 27

Urinary catheterization (male) 27

This chapter will describe various techniques which are part of the ‘stock-in-trade’ of the surgeon and therefore the student training in surgery. It will also describe some practical procedures with which the surgical trainee should be familiar.



Surgical incision


When choosing an incision, the following points should be considered:


• Access: the incision must be appropriately placed, large enough and capable of extension

• Orientation: if possible in the lines of skin tension (Langer’s lines) or skin creases. This leads to minimal distortion and better healing

• Healing potential of tissues

• Anatomy of underlying structures, e.g. the avoidance of nerves

• Good cosmetic result

• Abdominal incision: the common abdominal incisions are shown in Figure 2.1 and the indications for such incisions are indicated on the diagram. Paramedian incisions are rarely used nowadays but are included as their scars are still seen on the abdominal wall of the older patient.

image

Figure 2.1 Abdominal incisions.



Sutures


Students are usually introduced to suturing in a Clinical Skills Laboratory and during their A&E attachment. There is a wide range of suture materials, broadly divided into absorbable and non-absorbable, natural and synthetic, braided and monofilament.




Absorbable


These are plain catgut (natural monofilament); chromic catgut (natural monofilament); polyglycolic acid (synthetic braided – Dexon); polyglactin (synthetic braided – Vicryl); polydioxanone (PDS – synthetic monofilament). The strength of absorbable sutures declines according to the material, catgut being the quickest to lose strength. (Catgut sutures are no longer available in the UK because of their theoretical potential for transmitting spongiform encephalopathy and the fact that there are adequate supplies of acceptable alternative synthetic sutures.)



Non-absorbable


These include silk (natural braided); linen (natural braided); wire (stainless steel, usually monofilament); nylon (synthetic monofilament – Ethilon); polypropylene (synthetic monofilament – Prolene); expanded polytetrafluoroethylene (ePTFE – expanded monofilament). Non-absorbable sutures retain strength indefinitely and are used where strength is needed until repair is completed naturally, e.g. abdominal incisions and hernia repair. Non-absorbable sutures are often used for skin closure – synthetic monofilament used in subcuticular fashion giving the best cosmetic result.



Natural sutures


These are catgut, silk, linen, but their use is declining. Catgut is cheap but of variable strength. Silk handles well but, as with linen, it excites a strong inflammatory reaction.



Synthetic sutures


Types include Dexon, Vicryl, PDS, nylon, polypropylene and ePTFE. They are more expensive than natural sutures, but cause little tissue reaction. The degree of strength and absorbability can be controlled in manufacture.



Monofilament


These include catgut, polydioxanone, wire, polypropylene and nylon. They are smooth and pass easily through tissues and cause less tissue reaction. The disadvantage is that they are stiff, slippery and difficult to knot.



Braided (polyfilament)


These include polyglycolic acid, polyglactin, silk, nylon and linen. They handle well, but interstices harbour bacteria.



Wire


This is useful for closing the sternum in cardiac procedures and for orthopaedic procedures. It is strong, inert, but subject to breakage and handles poorly.



Gauge


Gauge (G) is the calibre of the suture and is expressed in numbers. Originally, the finest gauge was ‘1’ and the heaviest ‘4’ but with the development of finer sutures a scale of ‘0s’ was developed, the more 0s, the finer the suture, e.g. ‘0’, ‘00’ (2/0), ‘000’ (3/0). The finest suture is 10/0, used in eye surgery. The gauge used depends on the strength required, number of sutures, type of suture material being used and cosmetic requirements.



Needles


Needles are cutting or round-bodied. They come in a variety of shapes and lengths and may be straight or curved. Cutting needles are usually triangular in cross-section, and are useful for skin, tendon, and breast tissue. Round-bodied needles are oval or round in cross-section. Round-bodied needles are useful for GI tract and vascular anastomoses.



Methods of suturing


Sutures may be interrupted, continuous, vertical mattress, horizontal mattress or subcuticular. The choice depends on the site and nature of the operation and surgeon’s preference. Interrupted sutures may be used if there is a risk of infection, where some individual sutures may be removed to allow drainage. Subcuticular sutures may be used to give good cosmetic results, especially when using synthetic monofilament. Synthetic absorbable subcuticular sutures (e.g. Vicryl) may be used in children to avoid the trauma of suture removal.



Removal of sutures


The timing is a balance between strength of healing and a good cosmetic result. Some areas are better vascularized, under less tension, and therefore heal quicker than others. The following is a rough guide for the time of removal for different areas: face and neck (3–4 days); scalp (5–7 days); limbs (5–7 days); hands and feet (10–14 days); abdomen (8–10 days).



Alternatives to sutures


Alternatives include clips and staples. Michel clips appose the skin edges but do not penetrate the skin, and cosmetic results are good. Preloaded disposable staples have largely replaced Michel clips. Cosmetic results are excellent. Stapling devices are also available for GI anastomoses. Simple wounds in children can be closed with adhesive strips (Steri-Strips). Scalp lacerations in children can be closed using hairs adjacent to the wound edges as ‘sutures’. The hairs are knotted across the wound.



Drains


Drains are used prophylactically to drain anticipated collections, e.g. haematomas, bile leaks, urine leaks, or therapeutically to remove collections of pus, blood or other body fluids. Most drains consist of latex-based material or silicone. Red rubber tube drains are still used occasionally. Red rubber and latex drains form better tracks than silicone by exciting more tissue reaction. Drainage may be open or closed, suction or non-suction.




Open drainage


This is drainage by capillary action or gravity into dressings or stoma bags. Drainage may depend on position of patient. Sepsis is commoner with open drains.



Closed drainage


This is drainage into a bag or bottle attached to the drain. Usually, it is a suction system although it may be passive, working on the syphon system. Sepsis is less common with closed systems.



Suction drains


These help collapse down potential spaces as well as draining blood and other fluids. They are usually closed systems and therefore the risk of sepsis is less. Sump drains are open drains used in connection with suction. Sump drains contain an air inlet lumen to prevent blockage with soft tissue. Sepsis is a risk with sump drains.



Non-suction drains


These are used mainly intraperitoneally to drain gastrointestinal and biliary anastomoses. They are usually left for up to 5 days. They are usually rubber, PVC or silastic. If prolonged drainage is necessary and there is need for a tract to be established, rubber drains should be used as they stimulate fibrosis.



Complications of drains



• Sepsis: commoner with open drains

• Failure: especially suction drains which draw fat or omentum into the side holes

• Pressure or suction necrosis of the bowel leading to leakage of the intestinal contents with peritonitis

• Rarely, erosion into a vessel with haemorrhage.


Stomas (-ostomies)




Colostomy


A permanent colostomy usually opens onto the anterior abdominal wall in the left iliac fossa (LIF). It is flush with the skin and the contents of the bag are usually formed faeces. It is most commonly created following an operation for abdominoperineal resection of the rectum. A temporary colostomy in this position is usually consequent on a Hartmann’s procedure. Colostomies may occasionally be seen in the upper abdomen, either to the right or left of the midline, when they are defunctioning colostomies fashioned in the transverse colon to protect a distal anastomosis, although defunctioning ileostomies are preferred nowadays.



Ileostomy


An ileostomy is usually in the right iliac fossa (RIF). It is not flush with the skin but overhangs as a ‘spout’ for about 2.5 cm. This is so that the liquid small bowel content, rich in pancreatic enzymes, does not come into contact with the skin of the abdominal wall, resulting in tryptic digestion of the skin. The contents of the bag are fluid and are of the consistency of porridge. An ileostomy usually results from total colectomy with excision of the rectum (panproctocolectomy) for ulcerative colitis. Defunctioning loop ileostomies are used to protect distal anastomoses.



Urostomy (ileal bladder)


A urostomy is usually in the RIF. It is a blind-ended loop of ileum and looks not dissimilar to an ileostomy, i.e. it is not flush with the skin edge but looks like a ‘spout’. The ureters have been transplanted into the ileal loop. Urine drains from the ileal loop. It is usually created following total cystectomy for carcinoma of the bladder.



Mucous fistula


In some operations it may be necessary to bring out both ends of bowel, e.g. ischaemic bowel to assess viability. One end will be the functioning draining stoma (either ileostomy or colostomy) and the other end will be the functionless stoma termed a mucous fistula.

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Jun 14, 2017 | Posted by in GENERAL SURGERY | Comments Off on An introduction to surgical techniques and practical procedures

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