7.1 Surgical Instruments, Tray Setup & Sterile Field Maintenance

7.1 Surgical Instruments, Tray Setup & Sterile Field Maintenance

Minor office surgery is a vital component of outpatient clinical practice. The Certified Medical Assistant (CMA) plays an indispensable role in maintaining surgical asepsis, preparing surgical trays, inspecting and handling specialized instrumentation, assisting the operating provider during sterile procedures, and decontaminating equipment post-operatively. Strict adherence to surgical asepsis and meticulous instrument maintenance prevents healthcare-associated infections (HAIs), ensures patient safety, and protects costly surgical inventory.

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1. Structural Classification of Surgical Instruments

Surgical instruments are precision-crafted tools, predominantly forged from high-grade surgical stainless steel (martensitic or austenitic steel) or titanium. They are classified into four primary functional categories based on their mechanical action and clinical application: Cutting and Dissecting, Grasping and Clamping, Retracting and Exposing, and Probing and Dilating.

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|                             SURGICAL INSTRUMENT CLASSIFICATIONS                                  |
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| 1. CUTTING & DISSECTING | Sharp edges/blades to incise, excise, transect, or dissect tissues.     |
| 2. GRASPING & CLAMPING  | Jaws and ratchets to hold tissue, grasp needles, or occlude vessels.    |
| 3. RETRACTING & EXPOSING| Blades/prongs to pull back wound edges and maximize operative exposure. |
| 4. PROBING & DILATING   | Slender shafts or graduated rods to explore tracts or enlarge orifices. |
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1. Cutting and Dissecting Instruments

These instruments possess sharp edges or cutting surfaces designed to incise skin, divide anatomical layers, excise pathological lesions, or transect sutures and bandaging materials.

Scalpels & Disposable Blades

A surgical scalpel consists of a reusable handle and a detachable single-use surgical blade, or a pre-assembled disposable safety scalpel. Scalpel blades are attached using a needle holder (never fingers) to prevent percutaneous sharps injuries:

• Scalpel Handles:
  • #3 Handle: The standard, most common surgical handle in ambulatory medicine. Accommodates smaller blade sizes (#10, #11, #12, #15).
  • #4 Handle: A larger, heavier handle designed for deep structural incisions or thick skin (e.g., back, heels). Accommodates larger blade sizes (#20, #21, #22, #23, #24, #25).
  • #7 Handle: A long, slender handle used for deep surgical fields or narrow anatomical pockets.
• Scalpel Blade Types:
  • #10 Blade: Features a broad, curved cutting edge ("belly"). Used for making large, primary skin incisions through epidermis and dermis.
  • #11 Blade: An elongated, triangular blade with a sharp, pointed tip. Primarily used for "stab" incisions, incising abscesses during Incision and Drainage (I&D), and fine vascular cut-downs.
  • #15 Blade: A small, precise, curved blade with a shortened cutting arc. Ideal for delicate minor surgical excisions, punch/shave biopsies, cosmetic facial procedures, and pediatric surgeries.

Surgical Scissors

Surgical scissors vary widely in shaft length, blade curvature, and tip design (blunt/blunt, blunt/sharp, sharp/sharp):

• Metzenbaum Scissors: Characterized by long, slender shanks and thin, delicate, slightly curved blades with blunt tips. Designed strictly for dissecting delicate soft tissues, dissecting fascia, and separating tissue planes. Clinical Rule: Never use Metzenbaum scissors to cut sutures, drapes, or heavy dressings, as this instantly dulls and misaligns the fine cutting edges.
• Mayo Scissors: Sturdy, heavy-construction scissors with thick blades. Available in straight and curved patterns:
  • Curved Mayo: Used for cutting tough, dense fibrous tissues, heavy muscle fascia, and thick tendons.
  • Straight Mayo (Suture Scissors): Used exclusively for cutting surgical sutures, surgical mesh, and heavy fabric/drapes.
• Iris Scissors: Short, extremely delicate scissors with very fine, sharp-pointed tips (originally designed for ophthalmic surgery). Extensively used in dermatology and plastic surgery for micro-dissection and delicate suture snipping.
• Lister Bandage Scissors: Features an angled blade terminating in a smooth, flattened, blunt probe tip on the lower blade. The blunt probe tip slides safely between the patient's skin and dressing materials without gouging, puncturing, or cutting underlying tissue. Used to remove bandages, dressings, and cast paddings.
• Stitch / Suture Removal Scissors (Spencer Scissors): Possesses a distinctive small hook or crescent notch on the lower blade. The hook slides easily beneath a flush surgical suture loop to lift it gently away from the skin before cutting, preventing tissue traction.

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2. Grasping and Clamping Instruments

These instruments grasp biological tissues, secure surgical drapes, stabilize needles, or occlude blood vessels to establish surgical hemostasis.

Hemostatic Forceps (Hemostats)

Hemostatic forceps feature interlocking ratchet handles, ring grips, box locks, and transverse serrations on the inner jaw surfaces to compress severed blood vessels:

• Halsted Mosquito Forceps (5 inches): Small, delicate, fine-pointed hemostats with transverse serrations along the entire length of the jaws. Used to clamp tiny capillaries and bleeding arterioles in delicate facial or pediatric procedures.
• Kelly Forceps (5.5 inches): Sturdier hemostats with transverse serrations extending only along the distal half of the jaws. Used to clamp medium-sized blood vessels and grasp tough fascial connective tissue.
• Crile Forceps (5.5 to 6.5 inches): Similar in size to Kelly forceps, but possesses transverse serrations extending along the entire length of the jaws. Provides uniform clamping pressure across larger vascular bundles.

Tissue Forceps & Dressing Forceps

Forceps without ratchets are known as "thumb forceps" (tweezers), held between the thumb and index finger:

• Thumb (Smooth / Dressing) Forceps: Feature serrated blunt tips without interlocking teeth. Used for applying and removing sterile dressings, packing wounds with iodoform gauze, and grasping non-friable materials. Clinical Rule: Smooth forceps crush delicate living tissues if used to grip skin.
• Rat-Tooth Tissue Forceps: Feature interlocking sharp teeth (typically 1x2 or 2x3 teeth) at the jaw tips. The interdigitating teeth grasp slippery fascia, dense connective tissue, and skin margins firmly with minimal crushing force.
• Adson Tissue Forceps: Wide, flat thumb grasp area tapering down to very fine, delicate jaws (often with 1x2 micro-teeth). The gold standard in minor surgery for grasping delicate skin margins during suturing without causing tissue trauma.
• Allis Tissue Forceps: Ring-handled, ratcheted forceps with wide, curved jaws terminating in multiple interlocking fine teeth (e.g., 4x5 or 5x6 teeth). Grasps fascial layers, slippery tissue, or non-viable tissue to be excised, forming a secure basket clasp.
• Foerster Sponge Forceps: Ring-handled forceps with large, oval, fenestrated (ring-shaped) serrated tips. Used to hold sterile gauze sponges ("sponge sticks") for surgical skin prepping, blotting deep cavities, or absorbing fluid.
• Backhaus Towel Clamps: Features sharply pointed, curved, claw-like tips with a locking ratchet. Used to grasp and secure sterile surgical drapes and towels to the patient's prepared skin without slipping.

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3. Retracting and Exposing Instruments

Retractors pull back skin margins, muscular layers, and underlying organs to optimize visualization of the deep surgical operative field:

• Senn Retractor: A double-ended, hand-held retractor. One end features three sharp or blunt prongs (rake-like), while the opposite end features a smooth, flat, right-angled blade. Extensively used in minor outpatient surgery for superficial skin and plastic tissue retraction.
• Army-Navy (US Army) Retractor: A broad, double-ended hand-held retractor with smooth, curved, flat blades of unequal lengths on each end. Used to retract broad muscle layers and subcutaneous adipose tissue in deeper minor excisions.
• Skin Hooks: Slender, delicate handles with single or double sharp hooks at the tip. Used to gently elevate delicate skin edges during dermatological biopsies and cosmetic scar revisions without crushing dermal margins.

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4. Probing and Dilating Instruments

These instruments explore anatomical cavities, locate foreign bodies, trace pathological fistulas, or progressively widen physiological passages:

• Surgical Probe: A slender, flexible, malleable metal rod terminating in a smooth, bulbous (olivary) blunt tip. Used to explore wound depth, determine the trajectory of puncture wounds, trace sinus tracts, and locate foreign bodies.
• Specula (Plural of Speculum): Instruments with two or more hinged, movable blades used to dilate, open, and visualize body orifices and cavities:
  • Nasal Speculum (Vienna / Killian): Dilates the anterior nares for nasal packing, epistaxis cautery, or foreign body removal.
  • Vaginal Speculum (Graves / Pediatric): Dilates the vaginal vault for cervical inspection and Pap smear collection.
  • Ear Speculum: Funnel-shaped attachment for otoscopic examination of the external auditory canal.
• Uterine Sound: A long, graduated, malleable instrument calibrated in centimeters or inches, with a rounded bulbous tip. Used to measure the depth and anatomical axis of the uterine cavity prior to IUD insertion or D&C.
• Hegar / Pratt Uterine Dilators: Sets of smooth, graduated cylindrical rods used to progressively dilate the cervical os for intrauterine diagnostic or therapeutic procedures.

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2. Surgical Instrument Care, Inspection & Maintenance

Preserving instrument longevity, surgical sterility, and mechanical reliability requires a rigorous multi-stage decontamination and maintenance regimen:

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|                               INSTRUMENT DECONTAMINATION CYCLE                                   |
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| 1. POINT-OF-USE PRE-SOAK | Immediate cold water / enzymatic spray prevents bioburden drying.     |
| 2. ULTRASONIC CLEANING   | Cavitation sound waves dislodge microscopic bioburden from box locks. |
| 3. MANUAL INSPECTION     | Check ratchet tension, jaw alignment, box lock stiffness, and rust.   |
| 4. LUBRICATION ("MILK")  | 30-second dip in water-soluble surgical milk; air dry without wiping. |
| 5. PACKAGING & STERILIZE | Autoclave pouching with chemical indicators; steam sterilization.     |
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Decontamination Workflow

1. Point-of-Use Care & Presoaking: Immediately following a surgical procedure, heavily soiled instruments must be rinsed in cold water or sprayed with an enzymatic decontaminant solution. Hot water must never be used during initial rinsing because temperatures above $110°F (43.3°C)$ coagulate blood proteins, causing them to bake irreversibly onto metal surfaces and inside box locks.
2. Ultrasonic Cleaning: The preferred method for cleaning delicate surgical instruments. Ultrasonic cleaners generate high-frequency sound waves ($20\text{ to }40\text{ kHz}$) in a cleaning bath, producing microscopic vacuum bubbles that violently implode (acoustic cavitation). Cavitation dislodges blood, bone fragments, and microscopic bioburden from serrations, crevices, and box locks that manual scrubbing cannot reach. Instruments must be cleaned with ratchets fully opened and disassembled.
3. Inspection & Testing: Prior to packaging for autoclaving, the CMA must inspect each instrument:
   • Ratchets & Box Locks: Close ratchets to the first click; tap the ring handles lightly against a hard surface. If the ratchet springs open, the mechanism is sprung and must be repaired or condemned.
   • Jaw Alignment: Close jaws slowly; ensure teeth interlock precisely without gapping or lateral deviation.
   • Scissor Sharpness: Test cutting action across specialized testing material or latex-free rubber sheeting. Scissors must cut cleanly through to the tips without catching, snagging, or chewing.
4. Lubrication ("Instrument Milk"): Hinged instruments must be periodically lubricated to prevent friction wear, box lock stiffness, and electrolytic corrosion. Instruments are immersed for 30 to 60 seconds in a bath of water-soluble surgical lubricant ("instrument milk") and allowed to air-dry. Clinical Rule: Never use industrial mineral oils, silicones, or petroleum grease; these leave an impermeable oil barrier that blocks saturated steam from contacting the metal during autoclaving, resulting in sterilization failure.

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3. Principles of the Sterile Field & Aseptic Setup

A sterile field is a designated, microorganism-free workspace established by laying sterile drapes over a Mayo stand or surgical back table upon which sterile instruments, solutions, and supplies are assembled.

The Core Rules of Surgical Asepsis

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|                             THE CORE RULES OF SURGICAL ASEPSIS                                   |
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| 1. STERILE ONLY TOUCHES STERILE | Sterile objects touch only sterile items; unsterile touches unsterile.|
| 2. THE 1-INCH CONTAMINATED BORDER| The outer 1-inch perimeter of any sterile drape is non-sterile.     |
| 3. WAIST-LEVEL ELEVATION         | Anything below waist level or table height is considered contaminated.|
| 4. CONSTANT VISUAL MONITORING    | Never turn your back or walk away from an open sterile field.        |
| 5. ZERO REACH-OVER               | Never reach arms or torso across a sterile field; maintain margins.  |
| 6. AVOID STRIKE-THROUGH (WICKING)| Moisture penetrating a drape draws unsterile bacteria from beneath.  |
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1. The 1-Inch Non-Sterile Border Rule: The outermost 1-inch (2.5 cm) margin along the entire outer perimeter of any sterile drape, wrapper, or tray is considered non-sterile and contaminated. All sterile instruments and supplies must be placed strictly within the inner sterile perimeter.
2. Waist-Level Elevation Rule: Only items resting on the top horizontal surface of the Mayo stand at or above waist level (table height) are sterile. Any part of a drape hanging over table edges is contaminated. If a sterile gloved hand drops below waist level, it is contaminated.
3. Constant Visual Field Rule: A sterile field must remain in the continuous, uninterrupted line of sight of clinical personnel. Never turn your back on a sterile field and never walk out of the procedure room leaving an uncovered sterile field unattended. If a sterile field is left unattended, it must be presumed contaminated and discarded.
4. Zero Reach-Over Rule: Non-sterile personnel must never reach across, lean over, or sneeze/cough above a sterile field. Movement around the field must maintain a minimum buffer of 12 inches (30 cm).
5. Strike-Through Contamination (Wicking Dynamics): If liquid (sterile saline, water, antiseptic) is accidentally spilled onto a permeable sterile paper/cloth drape, the moisture wicks through to the unsterile table surface below via capillary action, pulling microorganisms upward onto the sterile field (strike-through). If strike-through occurs, the entire sterile field is contaminated and must be completely disassembled, re-draped, and reset with fresh supplies.
6. Air Current Minimization: Keep procedure room doors closed. Avoid rapid movements, excessive conversation, and fan usage near the sterile field to minimize airborne particle dispersion.

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4. Protocols for Adding Supplies & Pouring Sterile Solutions

Establishing and supplying the surgical field requires standardized aseptic transfer techniques:

Pouring Sterile Solutions onto the Sterile Field

When dispensing sterile liquids (e.g., normal saline, hydrogen peroxide, povidone-iodine) into sterile gallipots or splash basins on the surgical tray:

1. Verify Label Three (3) Times: Check the solution bottle: (1) upon retrieving it from storage, (2) immediately prior to opening and pouring, and (3) immediately after pouring before returning or discarding it. Confirm solution identity, concentration, sterility, and expiration date.
2. Inspect Solution: Check for clarity, particulate sedimentation, and bottle integrity.
3. Palm the Label: Hold the bottle with your palm covering the printed label. This prevents stray droplets from dripping down and staining, obliterating, or smearing critical medication information.
4. "Lip the Bottle": Remove the bottle cap without touching the inner rim (place cap upside down on an unsterile flat surface). Pour and discard the initial 1 to 2 mL of solution into a waste receptacle. This washes away any airborne dust or microscopic contaminants resting on the bottle's pouring lip.
5. Pour from Proper Height: Hold the bottle 2 to 6 inches (5 to 15 cm) directly above the sterile basin. Pour smoothly in a steady stream without touching the basin rim. Never pour from excessive heights ($>6\text{ inches}$), which causes splashing and induces strike-through contamination.

Techniques for Adding Sterile Items to the Field

• Drop Technique: Peel the flaps of a commercial peel-pack pouch outward and downward over your hands without touching the sterile inner contents. Hold the package 6 to 10 inches above the sterile field and drop the sterile item cleanly into the center of the field.
• Mitten (Glove-Wrapper) Technique: Peel the sterile wrapper back over your non-sterile hands, creating a protective sterile "mitten" of inverted paper wrapping. The sterile scrubbed provider can then grasp the exposed sterile instrument directly from your hands.
• Transfer Forceps Technique: Grasp sterile supplies using sterile transfer forceps (keeping forceps tips pointed strictly downward so soaking disinfectant does not run onto unsterile handles and drain back down) and gently deposit the item onto the field.

Surgical Instrument Classification, Design Features & Clinical Indications