7.2 Surgical Instrument Identification and Pack Prep

Surgical Instrument Identification and Pack Prep

Proper identification, care, and preparation of surgical instruments are critical responsibilities for the veterinary assistant. Clean, well-maintained, and properly sterilized instrument packs are essential for ensuring patient safety and preventing post-operative infections.

Surgical Instrument Identification

Surgical instruments are categorized by their function: cutting/dissecting, grasping/holding, clamping, and retracting.

1. Scalpels and Blades

Scalpels are used for primary tissue division.

• Scalpel Handles: The #3 handle is the standard handle used in small animal surgery. It accommodates smaller blades:
  • #10 blade: The most common blade, characterized by a curved cutting edge; used for making skin incisions.
  • #11 blade: A pointed, triangular blade; used for stab incisions or lancing abscesses.
  • #12 blade: A hook-shaped blade; used for suture removal or cat declaws.
  • #15 blade: A small, curved blade; used for precise, delicate incisions (e.g., ophthalmic surgery).
• The #4 handle is larger and used primarily in large animal surgery. It accommodates larger blades (such as the #20, #21, and #22 blades).
• Safety Note: Surgical blades must always be loaded and unloaded from the handle using a needle holder, never with fingers.

Common Scalpel Blades and Handles

2. Scissors

• Mayo Dissecting Scissors: Heavy-duty scissors with thick blades. Used for cutting tough, dense tissues (like fascia, cartilage, or connective tissue) and suture. Can be straight or curved.
• Metzenbaum Dissecting Scissors: Delicate scissors with long, thin shanks and short, thin blades. Used for blunt dissection and cutting delicate tissues (like subcutaneous fat or bowel walls). Crucial Trap: Never use Metzenbaum scissors to cut suture, gauze, or drapes, as this will quickly dull the blades and ruin them.
• Bandage Scissors (Lister): Feature a flat, blunt, probe-like tip on the bottom blade. This design allows the assistant to slide the scissors under a bandage to cut it without lacerating the patient’s skin.
• Suture Removal Scissors (Spencer): Feature a small crescent-shaped notch on one blade to lift and cradle the suture away from the skin before cutting.

Comparison of Dissecting Scissors

3. Thumb Forceps (Grasping/Holding)

Thumb forceps are held like a pencil and are used to grasp and manipulate tissues.

• Adson-Brown Thumb Forceps: The standard forceps in small animal surgery. They feature multiple rows of small, intermeshing teeth (typically 9x9 or 7x7) on each tip. This design provides a secure grip on tissues without causing significant trauma or crushing.
• Adson Tissue Forceps (Rat-Tooth): Feature large, interlocking teeth (commonly a 1x2 teeth pattern). They provide an extremely secure grip on tough tissue (like skin or fascia) but can crush and damage delicate tissues.
• Adson Dressing Forceps: Have flat tips with horizontal serrations (no teeth). Used for handling dressings or packing wounds, not for holding tissue.
• Cooley and DeBakey Forceps: Have fine, atraumatic horizontal ridges. Used in vascular and thoracic surgery.

4. Needle Holders (Needle Drivers)

Needle holders are used to grasp and manipulate suture needles.

• Mayo-Hegar Needle Holder: A standard needle holder with cross-hatched jaws for grip and a box lock ratchet.
• Olsen-Hegar Needle Holder: Combines a needle holder with built-in scissors located behind the jaws. This allows the surgeon to drive a needle and cut the suture without switching instruments. The main disadvantage is the risk of accidentally cutting the suture during needle driving.

5. Clamps (Hemostatic Forceps)

Hemostats are used to clamp blood vessels to control bleeding.

• Halsted Mosquito Forceps: Small clamps (around 3 to 5 inches long) with horizontal serrations running along the entire length of the jaw. Used for small, delicate blood vessels.
• Crile Forceps: Medium-sized hemostats with horizontal serrations running along the entire length of the jaw. Used for medium-sized vessels or tissue bundles.
• Kelly Forceps: Medium-sized hemostats with horizontal serrations running along the distal half of the jaw only.
• Exam Tip: Distinguishing Crile from Kelly is a classic test question. Remember: Crile = Complete (serrations along the whole jaw); Kelly = Half (serrations only on the outer half).
• Rochester-Carmalt Forceps: Large clamps with longitudinal grooving (running parallel to the jaw length) and cross-hatching at the tip. Used for clamping large tissue bundles (like ovarian pedicles during a spay) to prevent tissue slippage.

Key Hemostatic Clamps

6. Retractors

Retractors pull tissues aside to improve visibility of the surgical field.

• Handheld Retractors: Require an assistant to hold them in place. Examples include the Senn Retractor (double-ended; one end is a 3-pronged rake, the other is a flat L-shaped blade) and the Army-Navy Retractor (double-ended, smooth, flat, broad blades).
• Self-Retaining Retractors: Lock into place using a ratchet or thumbscrew. Examples include the Gelpi Retractor (single, sharp, outward-pointing prongs used in orthopedics and neurosurgery) and the Weitlaner Retractor (has rake-like ends with multiple outward-pointing prongs, typically 3x4). Balfour Retractor is a large self-retaining retractor used to retract the abdominal wall, featuring a central "bladder blade."

---

Pack Preparation and Care

The lifespan and sterility of surgical instruments depend on rigorous cleaning and pack preparation:

1. Decontamination & Pre-cleaning: Immediately after surgery, rinse instruments under cold running tap water. Cold water is essential because hot water will coagulate blood proteins, baking them onto the instrument. Manually scrub each instrument with a soft-bristled brush using a neutral-pH enzymatic detergent. Never use wire brushes or abrasive pads, which scratch the protective passivation layer of the stainless steel.
2. Ultrasonic Cleaning: Place scrubbed instruments into an ultrasonic cleaner containing a diluted enzymatic solution. The ultrasonic cleaner works through cavitation—high-frequency sound waves generate microscopic bubbles that implode. This creates a vacuum effect that pulls microscopic blood and debris out of hard-to-reach areas like box locks and serrations. Run the cycle for 10 to 15 minutes.
3. Lubrication ("Instrument Milk"): Rinse the instruments, then immerse them in a water-soluble lubricant bath (commonly called instrument milk). This bath prevents rust, keeps box locks moving smoothly, and extends instrument life. Important: Do not rinse or wipe off the lubricant after immersion; allow the instruments to air dry. Never use oil- or petroleum-based lubricants (like WD-40 or mineral oil) as they coat the instrument and prevent steam from sterilizing the metal surface.
4. Pack Assembly: Once completely dry, inspect each instrument for cleanliness and proper function (check that jaws align and hinges move smoothly). Arrange the instruments in a systematic order (e.g., using an instrument stringer). Crucial Rule: All ratchets and box locks must be left open (unlocked) to ensure steam can contact and sterilize the interlocking joint surfaces. Place a chemical indicator strip in the center of the pack.
5. Wrapping: Wrap the pack using double-thickness muslin cloth or barrier paper wraps. Wrap the pack using an envelope fold or a square fold, folding back a corner tab on each layer to allow aseptic opening later. Secure the wrap with autoclave tape. Write the date of sterilization, the type of pack, and the initials of the assembler on the tape.