Atlas of surgical instruments and equipment

This article provides an overview of the most common surgical instruments used in the operating room, including forceps, clamps, scissors, retractors, needle holders, and drainage spikes. Instruments are designed with specific characteristics depending on their intended use. Instruments with gold handles feature tungsten carbide inserts in the working end. For example, the blades of gold-handled scissors are made of tungsten carbide with a precision grind, which significantly increases their durability and resistance to wear.

Surgical Blades and Handles

Surgical blades are categorized by their shape and size, which dictate their specific clinical use. They are typically mounted on a Bard-Parker (BP) handle.

Safe Instrument Handling

Maintaining safety in the operating room is a primary objective for the surgical team .

• Sharps Safety:
  • Blades should be passed using a "neutral zone" or a kidney tray rather than hand-to-hand to prevent needle-stick and sharps injuries.
  • Blades must be mounted and removed from the handle using a needle driver or specialized blade remover; never use fingers.
• Grip Techniques:
  • Pencil grip: Used for precise, small incisions (e.g., with a No. 15 blade).
  • Palmar grip: Used for larger incisions requiring more pressure (e.g., with a No. 10 blade).

Anatomical Principles: Langer Lines

Langer lines (cleavage lines) are topographic lines that correspond to the natural orientation of collagen fibers in the reticular dermis .

• Surgical Significance: Surgical incisions should be made parallel to Langer lines whenever possible.
• Benefits:
  • Reduced tension on the wound edges.
  • Improved wound healing and minimal scarring .
  • Incisions made perpendicular to these lines are subject to greater tension and are more likely to result in widened, hypertrophic scars.

Scissors are used to cut through or blunt-dissect tissue and materials.

• Shape: varying lengths and curves (straight, curved, or angled) are used depending on the depth and position of the tissue
• Blade tips
  • Blunt/Blunt: used for dissection in deep areas without adequate visualization
  • Sharp/Blunt: a common general-purpose configuration
  • Probe-pointed (with button): used to protect underlying tissue when opening lumen-containing organs (e.g., the common bile duct)
• Examples: Mayo-Lexer and Metzenbaum (dissecting) scissors
• Scissors handling: Surgical scissors are generally held with the thumb and ring finger in the rings, similar to the needle driver, to provide stability and control.

Forceps are used to grasp tissue or surgical materials.

• Shape: chosen based on the location of the tissue (e.g., straight, angled, curved, or bayonet-shaped)
• Grasping surface
  • Anatomic (standard): features transverse serrations and a blunt tip. It allows for a firm grip by crushing tissue slightly without damaging the surface; often used in intestinal surgery or for applying electrocautery
  • Surgical (toothed): features interlocking teeth at the tip; provides a very secure grip on robust tissues like subcutaneous fat or fascia, though it can damage the tissue surface
  • Atraumatic: features specialized serrations (e.g., DeBakey serrations) to provide a gentle, non-crushing grip; essential for delicate structures in vascular and intestinal surgery.
• Examples: Adson (toothed/surgical), Potts-Smith, and DeBakey (atraumatic) forceps
• Forceps handling: Tissue forceps should be held in the nondominant hand like a pencil (pencil grip.

Avoid "toothed" forceps on delicate tissues (e.g., bowel or vessels) to prevent trauma, while using them on tougher tissues (e.g., skin) to prevent slipping.

Clamps are used to grasp and hold tissue or material passively over time using a locking ratchet mechanism.

• Grasping surface
  • Anatomic: used for coarser tissue that might be injured by teeth
  • Surgical: used for robust tissue or tissue intended for resection (e.g., fascia, subcutaneous fat)
  • Atraumatic: used for sensitive tissues in vascular or intestinal procedures
• Rigidity
  • Hard clamps: firmly grip and crush tissue (e.g., for clamping sutures or the peritoneum)
  • Soft clamps: secure tissue without damaging it (e.g., intestinal clamps often used with textile covers or vascular clamps that preserve arterial wall layers)
• Examples: Pean (anatomic arterial clamp), Kocher (surgical/toothed arterial clamp), Mosquito (smaller variant for fine work), and Mikulicz clamps

Retractors (and hooks) are used to pull back tissue, ensuring a clear view and access to the surgical field.

• Sharp: used for tough tissues like fascia or skin where there is no risk to delicate structures
• Blunt: used for retracting sensitive structures (e.g., nerves, vessels) or deep tissues
• Examples: Kocher, Roux, and Parker retractors, as well as Desmarres lid retractors

When holding a retractor, always emphasize the tip to maximize exposure for the surgeon.

Overview

Electrosurgery and energy-based devices are used to cut tissue and achieve hemostasis through thermal coagulation . Common clinical applications include endoscopic hemostasis for gastrointestinal bleeding and loop electrosurgical excision procedures (LEEP) for cervical abnormalities .

Comparison of Electrosurgical Modes

The choice between monopolar and bipolar modes is determined by the clinical context, safety requirements, and the proximity to vital structures.

Harmonic Scalpel

The harmonic scalpel utilizes ultrasonic energy to achieve coagulation and cutting with minimal lateral heat production.

• Working Principle: An oscillatory blade vibrates at high frequencies (20,000–50,000 Hz) to denature proteins.
• Advantages:
  • Highly precise cutting and dissection.
  • Effective at cutting through dense scar tissue.
  • Can be used safely close to vital structures due to minimal thermal spread.

Electrosurgery Waveforms

The thermal effect on tissue is controlled by adjusting the voltage and continuity of the electrical current.

1. Cutting mode: Utilizes low voltage and a continuous waveform to vaporize tissue.
2. Coagulation mode: Utilizes high voltage and an alternating (interrupted) waveform to create a thermal coagulum.

Clinical Safety Notes

• Cautery Pad: Essential for monopolar electrosurgery; improper placement or a small surface area increases the risk of thermal burns at the pad site.
• Pacemakers: Monopolar current can interfere with cardiac conduction; bipolar or ultrasonic devices (e.g., harmonic scalpel) are preferred in these patients.

Needle drivers are used to grasp and guide the needle during suturing. They feature a locking mechanism and often have cross-hatched serrations (carbide inserts) for a secure needle grip.

• Granularity: The cross-hatched serrations on the jaws are referred to as the "grain." The coarseness or fineness of the grain must be matched to the size of the needle being used.
• Examples: Mayo-Hegar and Crile-Wood needle drivers
• Needle driver grip: The choice of grip depends on the need for either strength or precision.
  • Thenar grip:
    • The instrument is held in the palm of the hand.
    • The thumb is placed distal to one hole, with the middle, ring, and little fingers distal to the other.
    • Allows for greater power and is useful for suturing through tough tissues (e.g., fascia).
  • Thumb-ring finger grip:
    • The thumb and ring finger are placed inside the rings of the instrument.
    • The index finger is extended along the shank for stability.
    • Provides maximum precision and control during delicate suturing.

• The choice of suture material depends on the tissue type, the required strength, and the clinical objective .
  • Absorbable vs. Nonabsorbable:
    • Absorbable (e.g., Vicryl, Monocryl): For deep dermal, mucosal, or fascial layers where removal is not required .
    • Nonabsorbable (e.g., Nylon, Prolene): For percutaneous skin closure or vessel ligation .
  • Needle Selection:
    • Tapered needles: Minimize trauma to delicate tissues (e.g., bowel, fascia) .
    • Cutting needles: Penetrate tough tissues (e.g., skin) with sharp edges

For a comprehensive guide on suturing techniques and detailed material properties, see the main AMBOSS article on Wound closure techniques.

Classification of Surgical Staplers

Mechanical staplers are categorized based on their configuration and the specific procedures for which they are designed.

Clinical Comparison: Stapling vs. Suturing

The choice between mechanical stapling and hand-sewn suturing depends on the anatomical location, surgeon preference, and the need for speed .

• Advantages of Stapling:
  • Efficiency: significantly faster than hand-sewing .
  • Accessibility: easier to use in narrow spaces (e.g., deep pelvis during an LAR).
  • Standardization: provides uniform tension across the entire closure.
• Disadvantages of Stapling:
  • Hemostasis: may provide inferior hemostasis compared to deep, well-placed sutures .
  • Cost: significantly higher per-unit cost than suture material.
  • Technical limitations: not suitable for very thick, inflamed, or friable tissue.

Surgical drains are used to remove air, blood, or other fluids from a wound or body cavity to promote healing and prevent complications like hematoma or abscess formation.

Technical Principle: The "Inside-Out" Technique

Most active (suction) drainage systems use a sharp metal trocar (spike) for placement.

• Mechanism: The drainage tube is attached to the blunt end of the spike.
• Placement: The spike punctures the skin from the inside of the surgical wound to the outside.
• Advantages:
  • ** sterility:** Prevents the tube from dragging external skin flora into the deep surgical site, reducing the risk of infection.
  • Precision: Allows for a separate, tight "stab" incision away from the main surgical wound.
  • Security: Ensures the perforated (draining) portion of the tube is positioned exactly where needed within the deep tissue.

1. Active (Closed-Suction) Drains

These utilize the "inside-out" technique with an integrated spike to establish a vacuum.

• Redon Drain: A high-pressure system typically used in orthopedics (e.g., total joint replacement) or for large tissue flaps to prevent deep hematomas .
• Jackson-Pratt (JP) Drain: A lower-pressure system consisting of a perforated tube connected to a collapsible bulb reservoir.
• Blake Drain: Similar to a JP drain but features a fluted silicone tube instead of perforations, which may reduce the risk of tissue ingrowth and clogging.

2. Passive Drains

These rely on gravity or capillary action and do not typically use the inside-out spike technique.

• Penrose Drain: A soft latex tube that allows fluid to drain onto a dressing; often placed directly through the main wound.
• T-Tube: A specialized drain used in the common bile duct to ensure bile flow during the maturation of a choledochotomy tract .

3. Specialty Drains and Catheters

• Pigtail Catheter: A small-bore drain with a curled tip to prevent migration; used for percutaneous drainage of abscesses or effusions (e.g., pericardial or biliary) .
• Chest Tube (Thoracostomy Tube): A large-bore, fenestrated tube used for draining the pleural space; placement typically involves blunt dissection and a finger-sweep rather than an inside-out spike .

While the general surgical tray provides the essential tools for opening, dissection, and closure, many procedures require specialized equipment to navigate complex anatomy or perform highly precise maneuvers. Surgical subspecialties often utilize unique sets of instruments that are tailored to their specific technical objectives.

Overview

Minimally invasive surgery (MIS) refers to surgical techniques that utilize small incisions ("keyholes") to minimize tissue trauma, reduce postoperative pain, and accelerate recovery. Laparoscopy is the primary MIS technique used to perform procedures within the abdominal and pelvic cavities. While traditional laparotomy (open surgery) requires large incisions for direct visualization and manual manipulation of organs, laparoscopy utilizes specialized, long-shafted instruments and a fiber-optic camera (laparoscope) introduced through small incisions made on the abdominal wall. Advanced iterations of this technique include Single-Incision Laparoscopic Surgery (SILS) and Robotic Surgery (e.g., Da Vinci system), which further refine the precision and cosmetic outcomes of the procedure.

Peritoneal access and insufflation

Laparoscopic surgery begins with the creation of a pneumoperitoneum (typically using CO₂) to provide visualization and operative space .

• Veress Needle: A spring-loaded needle used for the closed method of entry.
  • Design: Features a sharp outer needle for piercing the fascia and a blunt inner stylet that springs forward upon entering the peritoneal cavity to protect viscera.
  • Clinical Pearl: Proper placement is confirmed by the "drop test" or initial low insufflation pressures.
• Trocar and Cannula: The primary portal of entry for laparoscopic tools .
  • Sharp Trocar: Inserted blindly after the Veress needle; carries a higher risk of bowel or vascular injury.
  • Blunt Trocar (Hasson Cannula): Used for the open method (Hasson technique). The fascia is incised under direct vision, and the blunt-tipped cannula is secured to the fascia to prevent gas leaks.
  • Optiport/Visimport: A transparent-tipped trocar that allows the laparoscope to be inserted inside the trocar during entry, enabling "visual entry" through the tissue layers.

The Hasson cannula is blunt-tipped to prevent visceral injury during open entry, whereas a standard trocar may have a sharp tip for percutaneous entry.

Operating Instruments and Safety

Laparoscopic instruments are long, thin tools designed to pass through 5–12 mm cannulas.

• Insulated Instruments: Most laparoscopic graspers and dissectors feature a black insulation coating along the shaft.
  • Safety Warning: If this insulation breaks, capacitance coupling or direct current leakage can occur, causing unintended thermal injury to adjacent tissue (e.g., bowel).
  • Prevention: Regular inspection of insulation and the use of plastic trocars to reduce coupling risks.
• SILS (Single Incision Laparoscopic Surgery) Port: A multi-channel flexible port that allows the laparoscope and multiple operating instruments to be inserted through a single periumbilical incision.
  • Function: Allows for the insertion of multiple instruments (e.g., camera, grasper, dissector) through one single entry point to minimize scarring.

Robotic Surgery (e.g., Da Vinci System)

Robotic platforms provide a computer-interface between the surgeon and the patient, addressing many technical limitations of traditional laparoscopy .

• Disadvantages: Primarily the significantly higher cost and the current lack of haptic (tactile) feedback for the surgeon .

Comparison of Laparoscopic Entry Methods

While traditional laparoscopy uses multiple small ports, advanced systems further reduce trauma and improve precision.

1. Bone Preparation and Dissection

This category includes both power-driven and manual tools used to shape or cut the bone surface .

• Surgical Power Tools:
  • Drills and Saws: Used for high-speed drilling (e.g., for screws) and precise osteotomies (bone cuts) using oscillating blades.
  • Reamers: Specialized drill bits for hollowing the medullary cavity before the insertion of intramedullary nails .
• Manual Tools:
  • Periosteal elevator: A flat, broad-bladed tool used to strip the periosteum from the bone surface prior to fixation or osteotomy.
  • Bone chisel: Beveled on only one side of the tip; used for scraping or shaping the bone surface.
  • Bone osteotome: Beveled on both sides of the tip; designed specifically for cutting through bone (e.g., during a corrective osteotomy) .
  • Bone gouge: Features a curved, trough-like blade used to scoop out cancellous bone or marrow.
  • Bone curette: A small, spoon-shaped instrument used for scraping out cavities or removing diseased tissue (e.g., in osteomyelitis).

2. Bone Holding and Stabilization

These instruments provide the necessary "grip" to stabilize fractures or plates during internal fixation .

• Bone plate holding forceps: Features curved jaws with serrations to grip a bone plate against the bone surface.
• Lane bone holding forceps: Heavy-duty forceps with large, curved jaws and a ratchet to lock onto the shaft of a long bone.
• Fergusson bone holding forceps: Similar to Lane but often with a smaller, more focused grip for smaller bone fragments.

3. Bone Resection (Cutting and Nibbling)

Used to remove segments or fragments of bone, often utilizing double-action hinges for mechanical advantage.

• Double-action bone cutter: Features a compound hinge for cutting through small-to-medium bone shafts or fragments with minimal effort.
• Double-action bone nibbler (Rongeur): Used to "nibble" away small pieces of bone in layers; essential for smoothing bone ends or creating space in narrow areas.

4. Fixation Hardware

• Kirschner Wires (K-wires): Sharp, thin stainless steel pins used for provisional fixation or to stabilize small bone fragments .
• Redon Spikes (Drain trocars): Specialized sharp needles used in orthopedic surgery to pull drainage tubes through the skin from the inside out to prevent deep hematoma formation .

These tools are specialized for the sensitive anatomy of the female reproductive system and are designed to provide access, visualization, and traction with minimal tissue trauma .

1. Diagnostic and Localization Tools

Used to assess the internal anatomy before starting a primary surgical or diagnostic procedure.

• Uterine sound: A thin, flexible, calibrated metal rod used to measure the depth and determine the position of the uterus before procedures like IUD insertion or D&C.
• Bladder sound: Similar to a uterine sound but without calibrations; used to localize the bladder during pelvic surgery to prevent unintentional injury .

2. Exposure and Grasping Instruments

These tools are used to provide the necessary traction and visualization of the cervix and vaginal walls.

• Anterior vaginal wall retractor: A loop-shaped tool with a serrated surface, used to pull back the anterior vaginal wall to improve visualization of the cervix.
• Sponge-holding forceps (Foerster/Kornzange)
  • Clinical Pearl: Preferred for grasping the pregnant cervix because its blunt, looped surface provides secure traction without the "rat-tooth" trauma of specialized cervical forceps.

Comparison of Grasping Forceps

A table-based comparison helps in the rapid identification of these closely related instruments.

3. Obstetric Delivery Forceps

Specialized metal instruments designed to apply traction or rotation to the fetal head to facilitate delivery. These should only be used by skilled clinicians when specific criteria are met (e.g., full cervical dilation, engaged fetal head, and emptied maternal bladder).

Forceps should only be used by a skilled clinician when specific criteria are met, including full cervical dilation, engagement of the fetal head, an emptied maternal bladder, and known fetal position/attitude.