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Introduction to Surgery

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The instruments. The surroundings. Elimination of sources of infection. Surgical team ... Instruments. Instruments commonly in a basic surgical kit. Scalpel ... – PowerPoint PPT presentation

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Title: 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.
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