Introduction to Surgery

1
Introduction to Surgery
2
When to use Aseptic Surgery

• This is simply an introduction to some principles
  of surgical technique a detailed course is
  available on a CD
• http//www.digires.co.uk/dint.html

3
Halsteds Principles of surgery

• Handle tissues gently
• Control haemorrhage carefully
• Preserve blood supply to tissues
• Observe strict aseptic technique
• Apply minimum tension to tissue
• Ensure tissues are accurately opposed
• Eliminate dead space

4
Rodents do not get post-operative infection
examining the myth.Why the theory may have
arisen.

• Rodents do not get post-operative infection
  examining the myth.
• Why the theory may have arisen.
• There are two possible reasons that would explain
  why numerous research personnel
• working with rodents hold this opinion, either
  post-operative infection does not occur in
• these species or there is a failure to diagnose
  it when it does occur. It is important that we
• consider these two possibilities and weigh up the
  evidence.
• How does infection become established?
• The following criteria contribute to bacterial
  infection becoming established.
• Sufficient size of a bacterial inoculum for
  infection to occur an inoculum of the
• size105 / g or per ml of body fluid is required.
  The provision of a large catchment
• area for microorganisms to reach their critical
  number facilitates this. Long
• duration of surgery will also contribute the
  number of bacteria entering the
• surgical site is proportional to the time taken
  for surgery.
• Nutrients for growth large quantities of
  nutrient material, such as blood or serum,
• must be present to provide a suitable medium in
  which bacteria can multiply.
• Surgeons skill level the experience and
  expertise of the surgeon regulates the
• time taken for surgery and the magnitude of
  tissue trauma resulting from it.

5
Rodents do not get post-operative infection
examining the myth.Why the theory may have arisen

• There are a multitude of factors that may have
  contributed to a failure to diagnose
  postoperative
• infection in rodents.
• In cases where post-operative complications
  arise and the easily recognised signs
• of infection e.g. pus or death with peritonitis,
  are not observed, it is assumed that
• there is no infection present. Many personnel
  carrying out routine experimental
• surgery do not have extensive medical or
  veterinary training and would fail to
• recognise the more subtle signs of wound
  infections and transient infection postsurgery,
• such as malaise and behavioural changes.
• Post-operative infection does not necessarily
  cause the death of an animal. It may
• merely result in depressed success rates of a
  technique. The link between surgery
• and the sequelae may not be made, particularly if
  signs of infection are
• inapparent

6
Historical Note

• During the 1800s
• these ideas were developed and in 1867 Lister put
  forward his principles of asepsis,
• recognising a link between contamination of the
  wound and infection and he proposed
• two preventative measures.
• - Removal of necrotic tissue and dirt from wounds
• - Application of chemical disinfectants to the
  surgeons hands and to patients
• wounds. This involved the use of carbolic acid
  sprays, dressings and soaks but it
• was not very popular with doctors!
• Continued

7
Historical Note

• antiseptic surgery evolved into aseptic surgery.
• Here the aim was to reduce or eliminate
  contamination of the wound at the time of surgery
  instead of simply removing contamination from the
  wound. In 1886 the Germans introduced the idea of
  steam sterilization, and in 1891 they introduced
  an aseptic ritual. It wasnt until 1910 that
  the aseptic principle was fully accepted in
  America. In 1913 Halsted (whose Principles of
  Aseptic Technique were referred to above) began
  to use surgeons gloves. By the late 1940s
  aseptic veterinary surgery had become generally
  accepted and was being practiced widely. By the
  1960s all surgeons were wearing hats, masks, and
  sterile gowns and gloves when performing surgery.

8
Application of the Aseptic technique

• The application of the Aseptic technique is one
  which has reduced the complications related to
  surgical intervention and improved the success
  rate.
• The sources of infection are
• The surgeon
• The animal
• The instruments
• The surroundings

9
Elimination of sources of infection

• Surgical team
• Attire , sterile gowns , remove jewellery etc
• Gloves and scrubbing of hands
• Maintenance of sterility
• There are well developed rituals for these
  procedures
• Video

10
The animal

• Preparation of the animals is essential to
  prevent infection
• Clipping and shaving off the fur or hair
• Cleaning and disinfecting the site
• Draping the site to prevent cross contamination
• Maintaining the site in this condition

11
The environment

• A clean dust free environment which can be
  cleaned appropriately ( not a back room also
  serving as a store)
• An area with good lighting and circulation space
• Availability of equipment to ensure aseptic
  technique

12
Equipment

• Instruments must be capable of being sterilised
  via chemical or heat techniques
• Methods are discussed in the CD
• They should be suitable for the procedure ( i.e
  not the dissection kit used in 1st year )
• They should be well maintained and sharp
• Hot bead sterilisation methods can be useful for
  batches of animals

13
Instruments

• Instruments commonly in a basic surgical kit
• Scalpel handle blade
• Blunt ended scissors
• Fine ended scissors
• Dissecting forceps serrated and toothed
• Needle holders
• Swabs
• Drapes towel clips
• Haemostats
• Retractors
• Sutures etc

14
Healing

• Inflammatory phase
• a) Haemorrhage Blood vessels constrict and a
  thrombosis forms to slow haemorrhage, after a few
  minutes
• blood vessels relax, various cell mediators are
  released and a clot is formed. If this clot
  remains undisturbed it will provide a framework
  for the elements of repair.
• b) Inflammation The mediators released from the
  damaged cells cause a local accumulation of
  inflammatory cells. These inflammatory cells
  and other blood borne factors ensure the process
  remains localised, clear up infective debris and
  secrete locally active growth factors to
  stimulate the process of healing.
• Continued

15
Healing

• c) Primary wound contracture
• Local fibroblasts contract to decrease the
  surface area of the wound. The outward signs that
  may be observed during this acute inflammatory
  phase are
• Heat
• Redness
• Swelling
• Pain
• Repair
• If the body has been able to control infection
  (and in the context of surgical wounds this is
  more likely if aseptic surgical techniques are
  used) inflammation subsides and the process will
  progress to the repair phase.
• a) Epithelialization
• The cells in the bottom layer of skin at the
  edges of the wound migrate under the scab to
  cover the defect. In a moist, protected
  environment this occurs within 12-24 hours.
• Continued

16
Healing

• Granulation
• Capillaries and fibroblasts beneath the
  epithelial layer multiply and migrate inward.
  This
• forms granulation tissue, which is firm and pink
  in appearance and resistant to infection.
• This tissue bed supplies oxygen for
  epithelialization, provides collagen and plays a
  part in
• wound contracture.
• Contracture
• The granulation tissue pulls the skin margins
  inwards (20 wound contracture) as it
• matures into fibrous tissue. This contracture
  ceases when wound edges are apposed or
• the tension in surrounding skin is equal to that
  of the fibroblasts (approximately 5-9 days
• after wound formation). This process is
  beneficial as it decreases the area to be covered
• by epithelialization, however complications can
  arise at this stage. Some examples of these are
• Scar formation.
• Web effect contracture causes a webbing effect
  in areas that would normally be highly mobile and
  this may limit joint movement.
• Deformity contracture deforms or (partially)
  occludes a body opening/hollow organ.
• Incomplete closure too much tension is present
  as the wound contracts because of
• its size and site leading to incomplete closure.
• Maturation
• As fibroblasts continue to lay down collagen the
  granulation tissue is transformed into
• fibrous tissue and the collagen fibres along the
  lines of tension become thicker whilst

17
Closure

• The purpose of wound closure is to bring the
  opposing surfaces of a wound together to allow
  them to heal.
• It is apposition not strangulation
• The are of suturing is not easily gained however
  on it depends the final result of the closure
  process.
• Too much pressure and the wound will break down
  too little and the sides are not appropriately
  apposes and supported .

18
Closure Methods

• The intent is to achieve a primary repair where
  no scar should appear.
• Sutures It is important to get an correct bite on
  the tissue and to knot correctly. These can be
  absorbable or non absorbable Suturing Video
• Clips these can be useful if used correctly.
• The size of the clip should be appropriate to the
  animal
• Staples these are a modification of the staples
  but are easier to use and will normally not
  allow strangulation of the wound
• Glue for some small wound it can be useful but
  does not have a long life
• Animals tend to removed it when grooming

19
Summary

• This is a simple introduction to the process of
  surgery there anre many more aspects to it and a
  single lecture is not capable of teaching them.
• The theory and practice should be learnt side by
  side and practice of suturing technique should be
  done on dead animals or other teaching aids.