Surgical Technique
Surgical Technique
Instructor Information
Instructor: Dr. Sudheesh S. Nair, BVSc., MVSc., PhD
Position: Assistant Professor - Small Animal Surgery
Email: snair@rossvet.edu.kn
Laboratory: VMS 5650 Surgery Lab 1
LATF Code: LATF-36-216
Key Components of Operative Technique
Handling of Instruments: Proper manipulation of surgical tools is critical to prevent tissue trauma, ensure precision, and maintain sterility. This includes selecting the correct instrument for the task and using appropriate grips and movements.
Hemostasis: The control of bleeding is fundamental to maintaining a clear surgical field, preventing hematoma formation, and minimizing blood loss, which can impact patient recovery and overall outcome.
Handling and Care of Exposed Tissues: Tissues exposed during surgery must be treated with utmost gentleness to preserve their viability, prevent desiccation, and minimize inflammation and scarring. This involves keeping them moist and avoiding excessive manipulation.
Re-apposition and Support Tissues during Healing: Accurate alignment and appropriate support for surgical wound edges are essential for optimal wound healing, ensuring strong tissue repair, minimizing dead space, and reducing the risk of complications like dehiscence or seroma formation.
Instrument Handling
Techniques for Holding Instruments
Ringed Instrument Grips:
Forehand Grip:
This is the most common and versatile grip, offering excellent control and tactile feedback.
Fingers Used: Primarily the Thumb and Ring Finger, inserted through the rings.
Support: A tripod support is formed with the Index and Middle fingers resting along the shaft of the instrument, providing stability and allowing for fine movements and increased pressure when needed.
Function: Primarily used for precise dissection, cutting, and suturing, where controlled, delicate movements are paramount. It is generally not used for forceful clamp placement due to less leverage.
Backhand Grip:
This grip offers a different angle of approach and is often used for reaching structures that are otherwise difficult to access with a forehand grip.
Fingers Used: Primarily the Thumb and Index Finger, similar to holding a pen.
Support: Other fingers provide support along the shaft to control the instrument's angle and pressure.
Function: Useful for specific dissections, particularly in confined spaces or when a reverse angle is required, offering good maneuverability.
Hemostasis
Application of Hemostats on Pedicles
Types of Hemostats:
Straight Hemostats: Best for structures in direct line of sight and easy access.
Curved Hemostats: Ideal for reaching around structures or ligating vessels in awkward angles, allowing for better visibility around the tips.
Mixed Hemostats: A combination used based on surgical needs.
Application Order: When clamping a pedicle for ligation, use straight hemostats most proximally to provide a clear, initial stopping point and good visual orientation. Subsequently, use curved hemostats more distally. This arrangement creates optimal spacing for ligature placement, preventing crowding and allowing for easier, more secure tying of sutures around the pedicle.
Common Types of Hemostatic Instruments
Mosquito Forceps:
These are the smallest hemostats, characterized by fine, delicate jaws with full transverse striations (serrations).
Function: Primarily used for precise occlusion of small vessels, such as subcutaneous bleeders, muscle capillaries, or intestinal vessels, to achieve fine hemostasis without excessive tissue damage.
Kelly Forceps:
Medium-sized hemostats with serrations along only the distal half of their jaws.
Function: Used for clamping medium-sized vessels or small tissue bundles, offering a balance between firm grip and minimal crushing of tissue at the proximal jaw portion.
Crile Forceps:
Similar in size to Kelly forceps but distinguished by having transverse serrations over the entire length of their jaws.
Function: Provides a more secure and robust grip compared to Kelly forceps, making them suitable for clamping larger or more resilient vessels and tissue bundles where a strong hold is required.
Rochester-Carmalt Clamps:
These are large, robust hemostats with a combination of longitudinal and transverse serrations over their entire jaw length.
Function: Specifically designed for the secure ligation of large vascular pedicles and stumps, such as those encountered during splenectomies or ovarian pedicles. The distinct serration pattern ensures an exceptionally firm grip, preventing tissue slippage during manipulation and ligation.
Guidelines for Ligature Placement Using Hemostats
The tips of the hemostat should pass completely across the structure being ligated, extending approximately 1 to 1.5 cm beyond the tissue edge. This provides sufficient length for the ligature to be passed and tied securely without slipping off the clamped tissue.
Placement Precision:
Too far: If the hemostat is placed too far beyond the pedicle, the tissue might be held only by the very tips (the least holding area), increasing the risk of the ligature slipping off. Additionally, passing the suture may be more challenging.
Too close: If the hemostat is placed too close to the vessel's cut edge or not fully across the structure, there is a significant risk of vessel occlusion failure or ligature slippage, leading to hemorrhage.
In curved hemostats, the concave side should consistently point upward and away from the tissue that will be ligated. This orientation provides better visibility of the area where the suture needs to be placed and facilitates easier passage of the ligature under or around the hemostat.
Ovarian Pedicle Hemostat Application Guidelines
According to ROSSie guidelines, specific measurements are crucial for secure ovarian pedicle ligation:
Triple Clamp Technique: This technique mandates a maximum of 3 cm distance for the pedicle to be exteriorized. This limit ensures sufficient tissue is handled outside the body for safe clamping and ligation while minimizing intra-abdominal manipulation.
Modified Triple Clamp Technique: Due to anatomic variations among patients, a more conservative 2 cm limit is often imposed for pedicle exteriorization, further reducing stretching and potential trauma to the pedicle.
Spacing: Maintain a precise 3-5 mm distance between ligature placements using hemostats. This optimal spacing allows for individual ligatures to be tied without interfering with each other and ensures adequate tissue compression.
Minimum Distance: The hemostat positioned just proximal to the ovary must be at least 5 mm proximal to the ovarian tissue. This ensures that the ligature encompasses enough vascular and connective tissue to prevent bleeding and does not incorporate ovarian remnants.
Distal Hemostat Placement: The most distal hemostat should be placed less than 5 mm distal to the ovary, positioned across the proper ligament. This specific placement helps in controlling small vessels within the ligament and defining the ovarian resection plane while avoiding ovarian tissue.
Halsted’s Principles of Surgery
Key Principles: These principles, established by William S. Halsted, form the bedrock of modern surgical practice, aiming to minimize complications and promote optimal healing.
Gentle tissue handling: Minimizing mechanical trauma to tissues reduces inflammation, pain, and promotes faster healing. Excessive manipulation can crush cells and impair blood supply.
Meticulous hemostasis: Absolute control of bleeding prevents hematoma formation, which can act as a culture medium for bacteria, impair healing, and obscure the surgical field.
Preservation of blood supply: Maintaining adequate blood flow to tissues is critical for oxygen and nutrient delivery, essential for cellular viability and wound repair. Compromised blood supply leads to tissue necrosis.
Strict aseptic technique: Preventing contamination of the surgical field with microorganisms is paramount to avoid postoperative infections, which are a major cause of morbidity and mortality.
Minimum tension when closing wounds: Wounds closed under tension can lead to ischemia, dehiscence, excessive scarring, and pain. It's crucial to achieve tension-free closure.
Accurate tissue apposition: Precise alignment of similar tissue layers (e.g., skin to skin, muscle to muscle) promotes primary intention healing, resulting in stronger, less conspicuous scars.
Obliteration of dead space: Eliminating potential spaces where fluid (blood or serum) can accumulate prevents seroma and hematoma formation, which can impede healing and predispose to infection.
Origin: These principles were famously introduced by William S. Halsted during his tenure at Johns Hopkins University in the 1890s, fundamentally shaping surgical education and practice.
Other Surgical Rules
Time is Trauma: This adage emphasizes that while speed can be beneficial, it should never compromise meticulous technique. Prolonged surgery increases tissue exposure, desiccation, and anesthesia time, all contributing to patient trauma. However, rushing at the expense of precision can lead to errors and complications.
Body Handling Sequence Rule: "Eyes first and most, fingers next and little, tongue last and least." This principle highlights the importance of visual assessment (eyes) as primary, followed by gentle palpation (fingers) for confirmation, and finally, verbal communication (tongue) to explain or direct, focusing solely on critical patient-related details. Extraneous conversation should be minimized to maintain focus.
Complication Analysis: When a complication arises, the first step should always be to rigorously examine one’s own technique and practices. This promotes a culture of continuous learning and improvement, rather than immediately blaming external factors.
Tissue Handling Techniques
General Principles:
Always handle tissues gently to prevent cellular damage, inflammation, and potential necrosis. Use appropriate instruments or stay sutures for manipulation rather than grasping tissues forcefully.
Utilize stay sutures as necessary to hold tissues out of the operative field or to apply gentle traction, minimizing direct instrument trauma.
Dissect along natural tissue planes. These planes represent areas of least resistance and are typically avascular, allowing for more efficient, less traumatic dissection with minimal bleeding and preservation of vital structures. Employ the most direct approach possible to reduce tissue exposure and manipulation.
Incision Length: Ensure that the surgical incision is of sufficient length to provide adequate exposure to the underlying structures without requiring excessive retraction or stretching of surrounding tissues. A longer, well-planned incision can prevent iatrogenic trauma caused by struggling in a confined space.
Dissection Techniques:
Sharp dissection: Preferred for most scenarios using a scalpel or scissors to precisely cut through tissue layers. It creates clean edges, minimizes tissue crushing, and preserves tissue viability.
Blunt dissection: Primarily used to carefully separate tissues along natural planes, particularly to isolate vascular pedicles or nerves, by gently pushing and spreading with instruments (e.g., mosquito forceps, sponge sticks) rather than cutting. This reduces the risk of cutting vital structures.
Types of Instruments: Use instruments specifically designed for gentle tissue handling, such as Adson-Brown thumb forceps (with multiple fine teeth for broad, atraumatic grip), DeBakey forceps (longitudinal serrations), or smooth tissue forceps when appropriate.
Wound Lavage Technique
Moisture Management: Tissues should be kept consistently moist throughout the surgical procedure to maintain cellular viability, prevent desiccation, and promote optimal healing. Desiccated tissues are more prone to infection and poor wound closure. Moist tissues should always visibly glisten.
Intermittent Irrigation: Perform regular wound lavage using warm, sterile saline or other appropriate solutions to mechanically remove bacteria, surgical debris, and clots from the operative field. This significantly reduces bacterial load and the risk of surgical site infections.
Tools Used:
Bulb Syringes: These are effective for applying smaller volumes of fluid and for gentle suction to remove fluid and minor debris, particularly in delicate areas.
Suction Irrigation Sets: These sophisticated systems allow for continuous or intermittent high-volume irrigation and simultaneous powerful suction, efficiently clearing the surgical field during more extensive procedures.
Surgical Drains
Types:
Open Drains: Simple drainage devices (e.g., Penrose drains) that collect fluid via capillary action and gravity into an absorbent dressing on the body surface. They are open to the environment, increasing infection risk if not managed properly.
Closed Drains: More sophisticated, completely sealed systems (e.g., Jackson-Pratt (JP) Drain, thoracic drains) that use negative pressure (suction) to actively evacuate fluid into a collection reservoir. They minimize the risk of ascending infection and allow for precise measurement of fluid output.
Managing Hemorrhage
Types of Hemorrhage
Primary Hemorrhage: Bleeding that occurs acutely during the surgical procedure, typically due to the accidental transection of a vessel or inadequate initial hemostasis.
Intermediate Delayed Hemorrhage: Bleeding that manifests within the first 24 hours post-surgery. This can be caused by a rise in blood pressure, dislodgement of a clot, or a failing temporary ligature.
Secondary Delayed Hemorrhage: Bleeding that occurs after 24 hours post-surgery, often several days later. It is commonly attributed to ineffective or slipped ligatures, erosion of a vessel by infection, or premature degradation of sutures.
Risks Associated with Hemorrhage
Uncontrolled bleeding significantly obscures the surgical field, making it difficult to identify structures and increasing the risk of numerous complications:
Technical errors: Poor visibility can lead to inadvertent injury to adjacent structures or incomplete removal of pathology.
Infection rates increase: Blood is an excellent culture medium for bacteria. Hematoma formation provides an ideal environment for microbial growth, leading to higher rates of surgical site infections.
Hematoma formation: Accumulation of clotted blood can impair wound healing, increase postoperative pain, and potentially put pressure on vital structures.
Postoperative pain: Extensive bruising and tissue swelling from hemorrhage contribute significantly to patient discomfort.
Impaired wound healing: Hematomas prevent direct apposition of tissue layers and compromise local blood supply, leading to delayed healing, dehiscence, or excessive scarring.
Potential life-threatening scenarios: Severe or prolonged hemorrhage can result in hypovolemic shock, requiring blood transfusions and potentially leading to multi-organ failure or death.
Hemostasis Techniques
Approach: In the event of hemorrhage, it is crucial to maintain a calm and composed demeanor. Frantic or disorganized responses can exacerbate the bleeding or lead to further errors. A systematic approach is always best.
Temporary Management: Initial control of hemorrhage can often be achieved through temporary measures such as direct digital pressure applied with a clean sponge over the bleeding site, or the application of a tourniquet for extremity bleeding. These actions provide time to assess the situation and plan definitive hemostasis.
Topical Hemostatic Agents: These agents work by creating a physical matrix for clot formation or by activating the coagulation cascade.
Gelfoam
™: An absorbable gelatin sponge derived from purified porcine (pig) skin. It acts as a hemostatic scaffold, absorbing blood and providing a matrix for platelet aggregation and fibrin clot formation. It resorbs over 4-6 weeks.
Surgicel
™: An absorbable hemostat made from oxidized regenerated cellulose derived from plants. When it comes into contact with blood, it forms a gelatinous mass that aids in clot formation by providing a physical matrix and slightly lowering pH, which can enhance platelet aggregation.
Hemablock
™: A microporous polysaccharide powder, often derived from potato starch. When applied, it rapidly absorbs water from blood, concentrating clotting factors and platelets at the bleeding site, thereby promoting rapid clot formation.
Ligation Techniques
Types of Ligation
Transfixion Ligature: This technique involves passing a suture through the center of a vascular pedicle or vessel, creating a secure anchoring point, and then tying a knot around the entire structure. This method is highly effective for larger vessels or pedicles to prevent ligature slippage, as the suture is anchored within the tissue itself. It is particularly valuable for high-pressure vessels or stumps where security is paramount.
Circumferential Ligature: This involves simply tying a suture around the circumference of a vessel or pedicle without piercing the tissue. It is simpler and ideal for smaller to medium-sized vessels (typically up to 5 mm in diameter) where the tissue bulk is minimal and slippage risk is lower. However, ligatures applied rapidly or loosely are at a higher risk of dislodgement compared to transfixion ligatures, especially if the pedicle is under tension.
Vascular Clips
Types of Vascular Clips
Non-absorbable Clips:
Metal options: Commonly made of biocompatible materials like titanium and stainless steel. These offer strong, permanent occlusion of vessels and hollow organs. Titanium clips are preferred in many settings due to their inertness and minimal artifact on imaging.
Absorbable Clips: Made from biocompatible polymers (e.g., polylactic acid) that gradually resorb over time as tissue healing occurs. They are useful when a permanent foreign body is undesirable.
Advantages: A significant advantage of both titanium and polymer clips is that they generally do not interfere with advanced diagnostic imaging modalities such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). This minimizes artifacting, allowing for clear visualization of the surgical site and surrounding anatomy post-operatively, which is critical for follow-up and detection of complications.
Electrosurgical Techniques
Why Use High Frequencies?
Electrosurgical units utilize high-frequency electrical currents (above 10,000 Hz) to cut and coagulate tissue. This is crucial because frequencies below this threshold would cause neuromuscular stimulation, leading to unwanted nerve and muscle depolarization and involuntary contractions (tetany) in the patient. By operating at very high frequencies, this dangerous effect is avoided, allowing for safe surgical use.
Electrosurgery Frequency Range: Modern electrosurgical devices typically operate within a frequency range of 400,000 Hz (400 kHz) to 2.5 MHz. This range efficiently generates heat in tissues without stimulating nerves or muscles.
Advantages of Surgical Diathermy (Electrosurgery)
Electrosurgery offers several significant advantages over traditional mechanical cutting devices like scalpels:
Precise cutting: Allows for very fine, controlled incisions with minimal mechanical trauma.
Effective coagulation: Simultaneously seals blood vessels as it cuts, markedly reducing intraoperative blood loss and improving visibility of the surgical field.
Less postoperative pain: The sealing of nerve endings during cutting can contribute to reduced postoperative pain for the patient.
Faster recovery: Reduced blood loss and tissue trauma generally lead to quicker patient recovery times and shorter hospital stays.
Specific Techniques and Parameters
Electro-Incision (Cutting): Achieved with a continuous, unmodulated high-frequency current. The high current density rapidly heats cellular water to boiling, causing cell lysis and vaporizing tissue, resulting in a clean, precise cut with minimal lateral thermal spread to adjacent tissues.
Electro-Coagulation: Involves an intermittent or modulated high-frequency current. This allows for slower heating of tissues, leading to protein denaturation and desiccation of cells without vaporization. This seals blood vessels by shrinking and collapsing their walls, ensuring effective hemostasis.
Electro-Fulguration: A superficial tissue destruction method where the electrode does not directly contact the tissue. Instead, a sparking effect occurs between the electrode and the tissue, leading to superficial charring and dehydration. It is used for broad, superficial coagulation or desiccation of larger tissue areas.
Electro-Desiccation: Achieved by direct contact of the electrode with the tissue using a modulated current. The heat generated dehydrates the cells, causing them to shrivel and die, suitable for precise, superficial tissue destruction without carbonization.
Electrocautery Explained
Mechanism of Electrocautery
Current Type: Electrocautery uses a direct current (DC) to heat a metal electrode (often a loop, needle, or blade) to a high temperature. The current does not pass through the patient.
Application: The heated electrode is then applied directly to the tissue. The tissue damage (coagulation or cutting) occurs through direct heat transfer from the hot electrode to the tissue, essentially a form of thermal burning.
Challenges: Electrocautery is less common in modern practices, especially for major surgeries, due to its limitations. It offers limited control over the depth and extent of tissue damage, carrying a higher risk of collateral thermal damage and inconsistent hemostasis compared to electrosurgery.
Comparison with Electrosurgery
Electrosurgery Mechanism: In contrast, electrosurgery uses a high-frequency alternating current (AC) that flows through the patient's tissues. The current generates heat within the cells, leading to precise cutting or coagulation. Because the current passes through the patient, a patient plate (grounding pad) is required to safely complete the electrical circuit and disperse the current, preventing burns at unintended sites.
Monopolar and Bipolar Electrosurgery
Monopolar Electrosurgery
Current Characteristics: Operates with a current range of 1 to 10 mA and high frequencies (typically 300 kHz - 4 MHz). In this setup, the electrical current flows from an active electrode at the surgical site, passes through the patient, and returns to the electrosurgical unit via a large inert patient plate (grounding pad) attached to the patient's body. This creates a large circuit, and heat is concentrated only at the small active electrode tip. It is suitable for cutting and coagulating large areas.
Bipolar Electrosurgery
Current Flow: In bipolar electrosurgery, both the active and return electrodes are incorporated into the tips of a specialized forceps-like instrument. The high-frequency current flows only between these two tips, directly through a small amount of tissue held between them. Crucially, no patient plate is required, as the current does not flow through the rest of the patient's body. This provides localized, precise coagulation with minimal thermal spread, ideal for delicate tissues or patients with pacemakers.
Precautions in Electrosurgery
Patient grounding: Ensure the patient grounding pad is correctly applied, has good skin contact, and is positioned away from bony prominences and scar tissue to prevent alternative current pathways and burns.
Safety against flammable gases: Avoid using electrosurgery in environments with flammable anesthetic gases, skin preparation solutions, or intestinal gases, as sparks can ignite them, leading to fires or explosions.
Caution around devices such as cardiac pacemakers: Electrosurgical currents can interfere with the function of pacemakers and other implantable electronic devices. Specific precautions, such as using bipolar mode, reducing power settings, and having a defibrillator readily available, must be taken.
Proper Insulation: Regularly inspect instrument insulation to prevent accidental burns from exposed metal shafts.
Avoid direct contact with metal: Prevent the active electrode from directly touching metal objects or surgical implants to avoid arcing or unintended heating.
Advanced Electrosurgery Techniques
Electro-Incision & Electro-Coagulation
Electro-Incision: Achieved using a continuous, unmodulated waveform. This provides a very high current density at the tip of the electrode, causing rapid cell vaporization and a clean, precise cut. Peak voltage typically ranges from 1300 to 3300 V.
Electro-Coagulation: Involves an intermittent or modulated (pulsed) current. This allows for a waveform with lower average power but higher voltage peaks, promoting desiccation and protein denaturation without vaporization. The charring mechanisms produced by this technique effectively seal blood vessels, leading to hemostasis. The pulsed nature of the current allows for heat dissipation between pulses, limiting thermal spread.
High-Frequency Radio Surgery
Advantages: Also known as RF surgery, this technique utilizes very high-frequency radio waves, typically in the MHz range. It offers superior precision, minimal lateral thermal damage, and reduced scarring compared to conventional electrosurgery. This precision minimizes tissue charring and necrosis, leading to rapid healing.
Applications: Due to its delicate cutting and coagulating capabilities, it is widely used in cosmetic surgeries, ophthalmology, neurosurgery, and other delicate procedures where tissue preservation and aesthetic outcomes are critical. It can operate with specified current and voltage ranges that optimize tissue interaction.
Laser Surgery Techniques
Laser Applications
Benefits: Laser surgery offers extreme precision, allowing surgeons to target specific tissues with minimal impact on surrounding healthy areas. A major advantage is its ability to simultaneously cut and coagulate small vessels, resulting in minimal bleeding and a clearer surgical field, which is particularly beneficial in highly vascular tissues.
Thermal Effects: The interaction of laser energy with tissue is primarily thermal and depends on several factors: the laser power setting, the duration of exposure, the wavelength of the laser, and the specific characteristics of the tissue being treated (e.g., water content, pigmentation, vascularity). These factors determine whether the tissue is cut, vaporized, coagulated, or ablated.
Types of Lasers Used: Different lasers are selected based on their wavelength and tissue absorption properties:
CO2 Laser: Emits at a wavelength of 10,600 nm. This wavelength is highly absorbed by water, making it excellent for precise cutting and vaporization of soft tissue with very shallow penetration and minimal collateral damage.
Nd:YAG Laser: Operates at 1,064 nm. This wavelength has deeper tissue penetration and is well-suited for coagulation and deeper procedures, as it is less absorbed by water and more by hemoglobin and melanin.
Diode Laser: Commonly operates in the 800-980 nm range. It offers good absorption in hemoglobin and melanin, making it versatile for general soft tissue cutting, coagulation, and ablation, particularly useful for vascular lesions and dentistry.
High-Level Laser Therapy (HLLT)
Specifications: HLLT refers to therapeutic lasers with wavelengths typically between 800-1,064 nm and a power output over 1 watt. This high power allows for significant thermal effects.
Applications: Beyond traditional low-level laser therapy, HLLT is directly used in surgical procedures for precise cutting, tissue ablation (removal), and efficient coagulation of blood vessels, especially in fields like veterinary surgery, dentistry, and dermatology. It's distinct from therapeutic lasers that primarily aim to stimulate healing without significant thermal effect.
Smoke Evacuation during Surgery
Importance: When electrosurgical units and lasers are used, they generate a smoke plume (surgical smoke) through the vaporization of tissue. It is critically important to use smoke evacuation systems to effectively suction and remove these plumes from the operative field. This improves visibility for the surgeon and protects the entire surgical team.
Safety Note: Surgical smoke is known to contain a complex mixture of noxious agents, including toxic gases, particulate matter, and potentially viable viruses or bacteria (e.g., HPV, HIV particles have been identified in laser smoke). While these agents pose potential health risks (e.g., respiratory irritation, mutagenic effects), it is noteworthy that direct transmission of infectious diseases through surgical smoke to operating room personnel has, as of now, not been definitively documented as a routine occurrence with proper safety precautions.
Concluding Thoughts
Quote: “Lady’s finger for gentle care, eagle’s eye for focus, and lion’s heart for courage - with this trinity can one truly master the sacred art of healing by the scalpel.” This quote emphasizes the core virtues required of a skilled surgeon: precision and gentleness, unwavering concentration, and the mental fortitude to perform complex procedures.
Contact for Queries: snair@rossvet.edu.kn
Appreciation for Attention: Thank You!