Small Animal Surgery.docx

Why do surgery? 5R's - Repair - Remove - Reconstruct - Reconnaissance (Diagnose) - Revise Language - -otomy: to open - -ectomy: to remove - -ostomy: to create an opening - -plasty: to form/give form to - -pexy: to attach/affix - -rrhaphy: to suture - -centesis: t...

Why do surgery? 5R's - Repair - Remove - Reconstruct - Reconnaissance (Diagnose) - Revise Language - -otomy: to open - -ectomy: to remove - -ostomy: to create an opening - -plasty: to form/give form to - -pexy: to attach/affix - -rrhaphy: to suture - -centesis: to perforate/tap - -oscopy: to look Diagnostic approach: - Signalment - History - Physical Exam - Diagnostic testing: - CBC/biochem/UA/Imaging - Treatment trial Decision making: assuming we made a diagnosis and deciding if surgery is the best option: - Other options: knowingly neglecting condition, medical treatment, surgery not always the best option. - If surgery is the best option: what, when, where, who. - Decision based on combination of: patient, client and surgical factors +-----------------------+-----------------------+-----------------------+ | Patient | Client | Surgical | +=======================+=======================+=======================+ | 1/ signalment, age, | Does the client | When should it be | | breed, personality. | understand: 1/ | done | | | expected outcomes | | | 2/ pre-operative Hx | | What method is best | | taking, pre-existing | 2/ potential | | | illness, duration + | complications | Who should perform it | | cause of illness, | | | | condition. | 3/ extent of | Is the necessary | | | aftercare | equipment available | | 3/ physical exam, | | | | concurrent injuries, | 4/ costs involved | Where should it take | | illness. | each step of the way | place. | | | | | | 4/ diagnostics. | 5/ cosmetics | | +-----------------------+-----------------------+-----------------------+ - Halsted's Principles: Give the body every optimal chance at healing its own tissue - **Gentle handling of tissue** -- exposure is key (need to see what you're doing); avoid excessive handling. - **Meticulous haemostasis** -- reestablish the closed bleeding system. - **Preservation of blood supply** -- don't cut it unless you need to. - **Strict aseptic technique** -- minimizing negative effects of errors. - **Minimize tensions on** **tissues** -- causes discomfort post-surgery. - **Accurate tissue apposition** -- giving the healing process a headstart. Means you can minimize tension. - **Obliteration of dead space** -- residual void after tissue loss/dissection; can fill up with contaminants. - How does bleeding occur? 1/ Technical: - Inadequate repair of vessels or vascular structures that are knowingly opened or\ divided, whether purposefully or accidentally - Occult or undiagnosed, and thus unrepaired, injury to the vascular system - Damage during the course of surgery to organs or structures within the\ operative field - Damage during the course of surgery, or in the immediate postoperative period,\ to organs or structures remote from the surgical site 2/ Bleeding Disorder: - Primary haemostasis (platelets/vessels) - Secondary Haemostasis (coagulation factors) - Haemostasis: Creation of haemostatic plug: - Adherence - Activation - Aggregation - Haemostasis: Cell-based model - Better describes in vivo coagulation - Major differences from cascade model: - The role of tissue factor - Coagulation is localised to, and controlled by, cell surfaces. - Disorders of Primary Haemostasis: Thrombocytopaenia, Thrombopathia, Vascular Disorders. - Disorders of Secondary Haemostasis: Acquired, Inherited factor deficiencies, Nonpathologic. - Why does bleeding matter? - Intraoperative: - Reduced visualisation - Increased risk of infection - Increased dead space - Local effects: - Tissue devitalisation - Systemic effects: - Blood pressure - Hypoxia - Death - Characterising Bleeding: - Location: Internal vs External - Rate: Sudden vs Chronic - Volume - How much is there to lose: - Dogs = 70-90mL/kg BW (\~8%) - Cats = 40-60mL/kg BW (\~5%) - What we can measure we can monitor: - Intraoperative: - Suction - Swabs - Anaesthetic monitoring - Perioperative: - PCV - BW - Surgical site - Halsted's Principles that don't let bleeding start: GENTLE HANDLING OF TISSUE + PRESERVATION OF BLOOD SUPPLY. - Just in case: - Can pre-place clamps, ligatures or penrose drain around major blood sources so as to be able to quickly occlude blood supply. - Make the Bleeding stop: - Extend incision - Clear the surgical field (organs, instruments, sponges) - Swab or suction 2/ Options for Haemostasis: - Digital pressure (temporary unless small vessels) - Clamps (temporary) - Tourniquet (temporary) - Ligation - Electrocautery - Haemostatic sponge - Topical vasoconstrictors 3/ Make sure it does not recur - Release any clamps - Return to native site - Check at end of procedure before closure. - What if we need to replace it? 1/ Red cell replacement: - Whole, fresh blood - Whole, stored blood - Stored packed RBCs - Fresh frozen plasma (caniplas) - Platelet rich plasma (PRP) - Cryoprecipitate - Cryosupernatant - Exception to the rule: - Greyhounds: Hyperfibrinolytic syndrome = excessive fibrin breakdown = unstable clotting = coagulopathy. - Management: - Preoperative: 10-15mg/kg Transanemic Acid SLOW IV - Intraoperative: Consider Transanemic Acid 20mg/kg CRI - Postoperative: Cyclokapron 10mg/kg PO q8h - Wound Healing: the phases - Inflammation - Proliferation - Maturation - INFLAMMATION +-----------------------+-----------------------+-----------------------+ | **Haemostasis** | **Early | **Late inflammation** | | | Inflammation** | | +=======================+=======================+=======================+ | Mission objective: | Mission objective: | Mission Objective: | | avoid exsanguination | Establish an immune | Develop provisional | | | barrier + remove | extracellular matrix. | | Time frame: Minutes | debris | | | to hours | | Time frame: 3-5 days | | | Time frame: 0-72hrs | | | Key troops: Platelets | | Key troops: | | | Key troops: | Macrophages | | - Establish clot | Neutrophils | | | | | - Continue cell | | - Recruit other | - Kill bacteria | recruitment | | cells | | | | (neutrophils \> | - Breakdown ECM via | - Clean up | | macrophages \> | proteolytic | degenerating | | endothelial | enzymes | neutrophils | | cells \> | | | | fibroblasts) | - Phagocytose dead | - Release matrix | | | bacteria + matrix | metalloproteinase | | | debris | s | | | | | | | - Release | Key troops: | | | additional | Lymphocytes | | | cytokines. | | | | | - Modulate | | | | macrophage | | | | activity | | | | | | | | - Clean up | | | | degenerating | | | | neutrophils | | | | | | | | - Rlease matrix | | | | metalloproteinase | | | | s. | +-----------------------+-----------------------+-----------------------+ - PROLIFERATION +-----------------+-----------------+-----------------+-----------------+ | Angiogenesis | Fibroplasia | Contraction | Epithelialisati | | | | | on | +=================+=================+=================+=================+ | Mission | Mission | Mission | Mission | | objective: | objective: | objective: | objective: | | Creation of | recruit + | reduce wound | Resurface the | | microvascular | migrate | area | wound | | network | fibroblasts | | | | | into ECM. | Time frame: day | Time frame: | | Time frame: | | 6-20 | initiated | | 4-6dys | Time frame: | | within hours of | | | peaks day 7-14 | Key troops: | wound, | | Key troops: | | anchored | continues for | | Endothelial | Key troops: | fibroblasts | weeks. | | cells | Fibroblasts | transform into | | | | | myofibroblasts | Key troops: | | - Form tubes | - Produce | | Keratinocytes | | which | collagen to | - Arrange in | | | differentia | establish | linear | - Loosen | | te | provisional | fashion | attachments | | or involute | ECM | along | (desmosomes | | | | tension | + | | | | lines | hemidesmoso | | | | | mes) | | | | - Expression | | | | | of smooth | - Mobilise in | | | | mms | 'leapfrog + | | | | isotope + | tumbling | | | | appearance | fashion' | | | | of stress | | | | | fibre | - Phagocytic | | | | bundle. | | +-----------------+-----------------+-----------------+-----------------+ - MATURATION - Mission objective: Strengthen the wound + create robust physical barrier - Time frame: 12-18mths - Key troops: Fibroblasts - Continued, though reducing, collagen proliferation - Specific Tissues: - GIT - Fascia - Urinary Bladder - Bone - Impairment to healing: - Wound perfusion - Tissue viability - Fluid accumulation - Infection - Mechanical factors - Immune function - PREVENTION OF INFECTION: relies on Halsted principle \#4 = STRICT ASEPTIC TECHNIQUE - Contamination comes from: - Patients - Prewashing - Clopping of hair - Skin preparation - Initial scrub: - **Remove** transient flora - **Inhibit** Resident flora - Draping - Postop dressing - Personnel - Hands - Clothing - Hair - Mouth - Instruments - Not sterilized properly - Contaminated in surgery - Environment - The theatre or field. Ideally: - Sole use room - Easy to clean - Separate from, but close to, preparation room - Climate control w/ laminar flow, positive flow ventilation. - Instruments: The importance of sterilization - The destruction of all MO's on or in an object - Not: - Cleaning: removal of gross contaminants - Disinfection: - High = removes all organisms except some bacterial spores - Intermediate = removes all organisms except any bacterial spores - Low: Removes vegetative bacteria, some fungi and viruses. - Instruments -- The sterilization Process - Cleaning - Drying - Wrapping - Sterilisation - Steam - Ethylene oxide - Plasma - Chemical - Storage - Clean, dry, undisturbed area - May remain sterile for more than 24mths - Check every wrap/instrument/kit at opening before use. - If in doubt, re-sterilise - Instruments: Sterility Indicators - Physical - Chemical - Biological - Surgical Instruments - To cut - To grasp/hold - To retract - Miscellaneous - USE THEM FOR THEIR USE - Using instruments for procedures other than their intended use may cause damage - Performing procedures with incorrect instrumentation may lead to inefficient or imprecise surgery. +-----------------+-----------------+-----------------+-----------------+ | TO CUT | TO GRASP | TO RETRACT | MISCELLANEOUS | +=================+=================+=================+=================+ | **Soft | [NEEDLE | To deflect | \- Bandage | | Tissues:** | HOLDERS:]{.unde | tissue away | scissors\ | | | rline} | from area of | - Suture | | [SCALPEL:]{.und | | interest in the | removal | | erline} | Ratchet-hold, | surgical field; | scissors\ | | | Suture cutters, | hand-held; | - Alligator | | Sharp incision, | Cross-hatched | self-retaining. | forceps\ | | no crushing , | jaws: beware | | - Jacob's hand | | no damage to | severity of | [HAND-HELD]{.un | chuck\ | | adjacent tissue | grooves -- can | derline} | - | | | damage suture; | | Drills/taps/bit | | [SCISSORS:]{.un | Clamping force | [SELF-RETAINING | s\ | | derline} | should be less | ] | - Microsurgical | | | than the | | tools\ | | Not for skin. | bending force | [SUCTION TIPS | - Laparoscopic | | | of the needle. | ] | tools | | Do cause some | | | | | crushing. | [TISSUE | | | | | FORCEPS:]{.unde | | | | Can be: Curved | rline} | | | | or straight, | | | | | sharp-sharp, | Configuration | | | | blunt-blunt or | of jaw | | | | sharp-blunt; | serrations | | | | Plain or | determines use: | | | | serrated. | Tip-clamping | | | | | for | | | | **Bone:** | cross-serration | | | | | s, | | | | [RONGEURS:]{.un | Jaw-clamping | | | | derline} | for | | | | | longitudinal-se | | | | Forceps with | rrations; | | | | cupped + | Extent of | | | | blunted jaws; | crushing will | | | | used to | determine | | | | cut/retrieve | severity of | | | | small fragments | tissue | | | | of bone; | handling. | | | | Orthopaedic/neu | | | | | rological | [TOWEL | | | | surgery. | CLAMPS]{.underl | | | | | ine} | | | | [PERIOSTEAL | | | | | ELEVATORS:]{.un | | | | | derline} | | | | | | | | | | Used to elevate | | | | | soft tissues | | | | | from bone. | | | | +-----------------+-----------------+-----------------+-----------------+      - Instrument Care: - Clean - Inspect - Maintain - Sterilise - Fundamental Surgical Skills: 1. Instrument handling 2. Tissue dissection + manipulation 3. Suturing 4. Knot-tying 5. Haemostasis 6. Wound-closure - Instrument Handling: - Starts with correct selection of instruments - Articulating instruments in fingertips - Typically thumb + 4^th^ finger - Nonarticulating instruments used as extension of fingertips - Scalpel: - Goal = full thickness incisions with a single sweep -- perpendicular to tissue surface. - Tissue is stabilized by thumb + forefinger of non-dominant hand - Trauma: sawing, not perpendicular, excessive length or depth. - Scissors: - Goal = sharp or blunt dissection - Sharp dissection minimizes tissue trauma - Trauma: Crushing; Excessive dissection = dead space - Needle-holders - Inefficient use causes most time-wasting of any instrument - Handle suture only distal to anticipated knot - Trauma: bend needles, damage/weaken suture, excessive force through tissue. - Forceps: - Grasp or blunt dissect - When grasping, consider crushing - Only tissue that is being removed should be crushed - Haemostats - Tip clamping - Jaw clamping - Trauma: - Excessive pressure - Excessive time - Excessive tissue bundle - Excessive dissection - Thumb Forceps: - Trauma: - Wrong instrument selection - Avoid grasping intestinal wall - Excessive pressure/time - Retractors: - Basic exposure - Static, long-term - Usually self-retaining - Minor variation: - Focal, short-term - Usually hand-held - Trauma: - Incorrect size - Excessive pressure - Excessive time - No protection (moistened swab/sponge) - Suction: - Use in purposeful + directed manner - Choose tip for purpose - Trauma: - Entrapped tissue - Excessive pressure - Contamination - Tissue Handling: Dissection + Manipulation - Dissection: - Should ideally allow bloodless and precise access to desired location; Should be performed along tissue planes. - Manipulation: - Minimise where possible; Select instrument carefully - Halsted's principles for suturing + knots: - Gentle handling of tissue - Preservation of blood supply - Minimise tensions on tissues - Accurate tissue apposition - Obliteration of dead space - Suturing: - Goals: - Maintain tensile strength throughout healing process - Technically simple + quick to perform - Allow for precise wound edge approximation - Types: Interrupted + continuous - Interrupted: - More precise wound apposition - Inherently tension-relieving - Improved closure security - Can take more time and suture material - Simple interrupted, modified Gambee, mattress patterns: - Horizontal, vertical, cruciate, Lembert - Continuous: - Generally for non-cutaneous (internal) suture lines - intradermal, subcutaneous tissue, body wall, viscera - Less knots, therefore less suture material - Quicker and easier to perform - Can be challenging to manage tension - Continuous, Ford interlocking, horizontal mattress, purse-string, Cushing, Connell, continuous Lembert - Knot Tying: - Principles 1\. Goal: Simplest, secure knot for the suture material and situation 2\. Avoid friction between strands 3\. Use appropriate tension 4\. Use even tension 5\. Avoid damage to suture material - Knot Tying -- Ligation: - Goal of ligation: Strangulation (of vessel or other structure) - Should tighten readily, and remain tight - Security and tension dictated by first throw - Can be bilateral or unilateral - Can be simple/circumferential or transfixing - May use single or double ligations - Needles + Sutures - Needles: Point, Body, Shape, Diameter, Cord length/bite width, Radius, Overall length, Swage Suture: - Monofilament (single strand) - Multifilament (braid) - Suture: - Coatings - Handling - Knot tying - Antibiosis - Other coatings have been trialled - Absorbable - Typically synthetic nowadays - Rapid, moderate or slow - Non Absorbable - Typically synthetic (as opposed to silk) - Slow breakdown - Generally used externally - Other tissue-closure devices - Staples, vascular clips, tissue glue (cyanoacrylate) - Factors associated with wound closure - Location: - Tension lines - Tissue volume - Blood supply - Contamination - Wound Classification (Contamination) - Contamination: The presence of microbes on a surface - Colonisation: The replication of surface microorganisms - Clean - Clean-contaminated - Contaminated - Dirty - Gustilo-Anderson Open Fracture Classification - Type I: Open Fracture with a wound smaller than 1cm - Type II: An open fracture with a wound larger than 1cm without extensive\ soft tissue damage, flaps or avulsions - Type III: Open fracture with extensive soft tissue damage - Type IIIA - Type IIIB - Type IIIC - Bandaging - Promote healing - Protect wounds - Absorb exudate - Eliminate dead space - Manage pressure - Administer topical medications - Modulate pain - Improve aesthetics - Restrucit movement - Immobilise/stabilise/support underlying structures - Contact/Primary ; Intermediate/Secondary ; Outer/Tertiary - Bandaging: Contact/primary layer - Establish environment to support healing - Barrier - Exudate transfer/absorbency - Selective: - Autolytic debridement - Granulation - Epithelialisation - Contraction - Bandaging: Secondary/intermediate layer - Holds dressing in place - Absorbs exudate through from primary layer - Typically 2 components: - Inner absorbent material - Stabilising material - Bandaging: Tertiary/outer layer - Establishes sub-bandage pressure - Materials: - Elastic or inelastic - Cohesive or adhesive - Porous or waterproof - Custom cut or commercially produced - Can be marked for messaging - Bandaging: Placing circumferential layers - 50% overlap in spiral manner - Distal-proximal, proximal to distal, distal to proximal - Last layer should end proximally - Unroll/reroll elasticated bandage material - Should be able to insert a finger between bandage and underlying tissue - Bandaging: When to change - Before drying of primary contact layer - Before strikethrough at tertiary layer - At any point that discomfort, slippage, odour or moisture is noted - Needs to be gauged at each change to estimate timing for next change - Bandaging: Complications - Slippage - Soiling - Damage - Incorrect pressure - Inappropriate interval between changes - Take care when changing - Negative Wound Pressure Therapy (NWPT) - Experimental - conflicting evidence - Open cell foam/gauze over wound bed - Drainage tube over foam/gauze - Occlusive dressing over everything, adhered to skin - Vacuum applied (-125mmHg) to entire dressing - Halsted's Principles for Surgical Drains: Obliteration of dead space - Drain Pros & Cons - Remove accumulations - Relief pressure - Evacuate unwanted material - Induce inflammatory response - Decrease tissue resistance to bacterial colonisation - Can leach into tissue - Can cause discomfort - Drain types: Open passive + Close active - Closed Active Drains - Reduce risk of infection - Prevent skin excoriation from drain fluid - Closed system allows application of suction - Reservoir collection - F = dPπr4/8nL - Most common type is Jackson-Pratt - Reservoir collection - External fixation of reservoir - Negative Wound Pressure Therapy (NWPT) - Experimental - conflicting evidence - Open cell foam/gauze over wound bed - Drainage tube over foam/gauze - Occlusive dressing over everything, adhered to skin - Vacuum applied (-125mmHg) to entire dressing - Drain Placement - Distal end placed in the deepest aspect of the cavity to be drained - Proximal end that provides the shortest distance to the outside - Dependent (if passive drain) - Not through primary incision - Should not compromise future reconstructive surgery - Should allow reexcision/radiation in mass removal - Reduce tacking sutures within wound - Secure at proximal exit/egress - Drain Removal - Remove as early as possible - Judge by fluid production, not by time - Volume will plateau but rarely cease entirely - Remove slowly and gently - Drain holes are contaminated - left to heal by second intention - Can be covered with a dressing for several days - Can stagger removal from deep cavities - Can culture drain if indicated - Drain Complications: - Infection - Pain/discomfort - Tissue reaction - Foreign body - Only flush when drainage is essential for patient's recovery - No current report of drain-tract metastasis - Halsted's principles that apply to surgical site infections: Strict aseptic technique - Judicious Use in the Surgical Patient - Nature of contamination - Duration of surgery - Duration of anaesthesia - Surgical site preparation - Method of wound closure - Comorbidities - What/When/How often/How long - "One size fits most" - Cephazolin - 22mg/kg IV - Commence within 60 minutes of surgery\* - Repeat every 90 minutes - Discontinue with 24 hours of surgical closure - Biofilm: A layer of bacteria or other microbes that grows on and sticks to the surface of a structure. A biofilm may cover natural surfaces, such as teeth. They may also grow in or on medical devices, such as catheters or artificial joints. Bacteria growing as a biofilm are hard to treat with antibiotics. - Gossypiboma: A mass of cotton material (usually gauze, sponges and towels) inadvertently left int he body activity at the end of a surgical operation. - Requirements for a wound infection - A source of an infectious agent ✤ Virulence factors help invade, cause disease and evade host defences - A mode of transmission - A susceptible host - Should we perform dentistry at the same time? 1\. A source of an infectious agent - Mouth 2\. A mode of transmission - Aerosolised bacteria, bacteraemia 3\. A susceptible host - Anaesthetised, hypothermic, possibly unwell, possibly implant placement - Managing SSI's 1. Prompt recognition of an abnormality 2. Determine depth/extent of SSI 3. 3\. Identify factors that might influence treatment 4. Consider complicating factors - Patient, client, surgical site - Managing SSI's - **Specimen Collection and Testing** - Culture sample: Deepest and most representative site - Beware contaminants/commensals at superficial sites - Before antimicrobial administration if possible - Transport and processing ASAP (\< 24 hours) - In-house cytology/gram-stain may help initial treatment choice - **Antimicrobial Therapy** - Empirical treatment normally indicated - Based on site, susceptibility, drug options and patient factors - Often amoxycillin/clavulanic acid as a starting point - Reassess after culture results are received - Local therapy (biocides such as CHG) may be indicated - **Revision** - Explore the site - Remove debris - Remove foreign material - Drain abscess - Implant antimicrobial-impregnated materials - Implant removal - Incision Care: - Clean - Dry - Protection - Restrict motion - Antibiotic gel - Cold packing - Laser therapy - Infection: - Infection \> Inflammation - Cardinal sx of inflammation - Dehiscence: A partial or total separation previously approximated wound edges, due to a\ failure proper wound healing - Consideration for Closure: - Contamination - Tissue necrosis - Tension - Location - Patient factors - Postoperative Patient Assessment - Wound assessment - Infection - Dehiscence - Patient assessment - Comfort - Function - Comfort - Demeanour - Appetite - Lameness - Pain to touch - Respiratory rate and effort - Heart rate - Function - Physiological parameters - Lameness - Wound healing - Urination and defecation - In general, we are expecting continual improvement: - Discharge reducing - Comfort improving - Wounds healing - A return to normal for that patient +/- improvement - Intervention: - What has gone wrong? - How has the recovery altered from the expected process? - How badly has it gone wrong? - What are the likely causes of the complication? - What are the consequences of those complications? - What can be done about those complications? - Will intervention resolve the complication? - Surgical Oncology: Why sample - What is it? - Where is it? - How is it likely to behave? - What can I do about it? - Best Practice 1/ Sample (cytology/biopsy) 2/ Grade (histopathology) 3/ Stage (CBC/Biochem/UA/Imaging/LN sampling) 4/ Treat (Surgery, chemotherapy, radiation therapy, immunotherapy) - Sampling principles - Appropriate size and representation of tissue - Handle gently - Typically at margin of normal and abnormal tissue - Be mindful of definitive excision - Try not to spread disease - Cytology vs. Biopsy - Cytology - Typically performed via fine needle aspirate or fenestration - Can be performed as impression smear, swab or scraping - Cells ejected onto a slide - Prepared by squash prep or line pre - Biopsy: Requires taking a section of tissue and fixing in formalin - Biopsy Techniques - Needle-core biopsy - Punch biopsy - Incisional biopsy - Excisional biopsy - Endoscopic biopsy Needle-core biopsy Punch biopsy ------------------------ -------------------  Incisional Biopsy Excisional Biopsy  Endoscopic Biopsy Margins  - Postoperative Margins - We need to find out whether we've "got it all" - Preserve tissue structure of excised mass - Ink margins - Place sutures to mark edges - Fix properly (Formalin:tissue 10:1) - Minimally Invasive Surgery -- WHY? - Decreased pain - More rapid return to function - Lower infection rate - Magnification/greater visualisation - Considerations - May increase surgical time - Steep learning curve - Proficiency in open surgery - Equipment - The "Five Boxes" 1\. Monitor 2\. Camera box 3\. Light source 4\. Insufflator 5\. Data recorder - Arthroscopic equipment - Arthroscopy: The examination of the inside (endoscopy) of a joint - Arthroscope - Cannula - Light source - Camera - +/- Pressure pump for irrigation - Instruments - Light source - Camera: - Irrigation: - Instruments: - Similar to joint surgery otherwise - Graspers, punches, curettes, knives, awls, probes - Limb positioners and joint distractors - Power tools - Shavers - Needles, syringes, bowls, haemostats, towel clamps, closure materials