16- Surgical Techniques & Technology Explains Flashcards
What is electrosurgery?
Electrosurgery is a technique that uses the heat generated by high-frequency alternating electrical current to treat living tissues.
How does electrosurgery generate heat in tissues?
The application of a voltage across human tissue creates an electrical circuit, and the tissue acts as a resistor. The resistance of the tissue, determined by its water content, leads to the formation of heat.
What is the frequency range at which most diathermy units operate?
Most diathermy units operate at a frequency between 200,000 kHz to 5 MHz.
What are the three main therapeutic modalities that can be achieved with electrosurgery?
Electrosurgery can deliver three main therapeutic modalities: cutting, coagulation, and blend.
What is the purpose of the cutting modality in electrosurgery?
The cutting modality in electrosurgery utilizes a sinusoidal and non-modulated waveform with high average power and current density. It allows for precise cutting without causing thermal damage to the tissue.
How does the coagulation modality work in electrosurgery?
The coagulation modality in electrosurgery uses a modulated current with intermittent dampened sine waves of high peak voltage. It results in the evaporation, rather than vaporization, of intracellular fluid and the formation of a coagulum.
What is the purpose of the desiccation modality in electrosurgery?
The desiccation modality in electrosurgery involves the active electrode being in direct contact with the tissue. It uses a low current and high voltage system, resulting in the loss of cellular water without causing protein damage.
What does the fulguration modality in electrosurgery involve?
The fulguration modality in electrosurgery uses an electrode probe held away from the tissue. It produces a spray effect with local, superficial tissue destruction. It operates using a low amplitude and high voltage system.
What is the purpose of the blend mode in electrosurgery?
The blend mode in electrosurgery combines alternating cutting and coagulation modes. It has a total average power that is less than with cutting alone.
What is the suture material called that is braided and biological?
Silk
What are the common uses for silk sutures?
Anchoring devices and skin closure.
What is the durability of silk as a suture material?
Theoretically permanent, although its strength is not preserved.
What is the suture material called that is braided and biological, degrades rapidly, and is not available in the UK?
Catgut
What are the special points to note about silk sutures?
Silk sutures knot easily and result in poor cosmesis.
How long is catgut suture typically used for?
5-7 days for short-term wound approximation.
What are the drawbacks of catgut sutures?
Poor cosmesis and unpredictable degradation pattern.
What is the suture material called that is braided, biological, and can be used for deep tissue apposition for up to 12 weeks?
Chromic catgut
What are the drawbacks of using chromic catgut sutures?
It has an unpredictable degradation pattern and is not in use in the UK.
What is the synthetic monofilament suture material called that can last up to 3 months (longer with thicker sutures) and has widespread surgical applications?
Polydiaxanone (PDS)
What are some common surgical applications for polydiaxanone sutures?
Visceral anastomoses, dermal closure, and mass closure of the abdominal wall.
What type of suture material is polyglycolic acid (Vicryl, Dexon)?
Braided synthetic
How long can polyglycolic acid sutures be used for?
Up to 6 weeks.
What are the advantages of using polyglycolic acid sutures?
Most tissues can be apposed using polyglycolic acid, and it has good handling properties.
What should be avoided when using polyglycolic acid sutures for skin closure?
The dyed form of this suture should not be used for skin closure.
What is the suture material called that is synthetic, monofilament, and permanent?
Polypropylene (Prolene)
What is polypropylene commonly used for?
Polypropylene is widely used and is the agent of choice for vascular anastomoses.
What are the drawbacks of using polypropylene sutures?
Polypropylene sutures have poor handling properties.
What is the suture material called that is synthetic and braided?
Polyester (Ethibond)
How durable is polyester (Ethibond) as a suture material?
It is permanent.
What are the common uses for polyester (Ethibond) sutures?
Polyester (Ethibond) sutures are useful for laparoscopic surgery due to their combination of permanency and braiding.
What are some special points to note about polyester (Ethibond) sutures?
Polyester (Ethibond) sutures are more expensive and have considerable tissue drag.
What is the main difference between absorbable and non-absorbable sutures?
Absorbable sutures are designed to degrade over time, while non-absorbable sutures are not intended to degrade and require removal.
How do absorbable materials degrade in the body?
Absorbable materials are typically degraded by macrophages hydrolyzing the material.
What type of sutures are commonly used in cardiac and vascular surgery?
Non-absorbable sutures are usually used in cardiac and vascular surgery.
In which situations would absorbable sutures be preferred?
Absorbable sutures are preferred when long-term tissue apposition is not required.
How is suture size indicated?
Suture size is indicated by an index number, where a higher index number corresponds to a smaller suture. For example, 6/0 prolene is finer than 1/0 prolene.
What is the relationship between suture size and tensile strength?
Finer sutures have less tensile strength.
Give an example of a suitable use for 6/0 prolene sutures.
6/0 prolene sutures would be ideal for small caliber distal arterial anastomoses, but not suitable for abdominal mass closure.
What are the characteristics of braided sutures compared to monofilament sutures?
Braided sutures generally have better handling characteristics than non-braided sutures. However, they are associated with higher bacterial counts.
Why are braided materials unsuitable for use in vascular surgery?
Braided materials are potentially thrombogenic, making them unsuitable for use in vascular surgery.
When are skin flaps or grafts used in tissue reconstruction?
Skin flaps or grafts are used when primary wound closure is not possible or would result in significant cosmetic defect or functional disturbance due to wound contraction.
What is the reconstructive ladder in tissue reconstruction?
The reconstructive ladder includes methods such as direct closure, grafting techniques (split thickness and full thickness), skin substitutes (composite), flap techniques (local, regional, distant), prelamination techniques, and tissue expansion.
What are the different types of local flaps?
The different types of local flaps include transposition, pivot, and alphabetplasty (e.g., Z-Y).
What are the different types of regional flaps?
The different types of regional flaps include myocutaneous, fasciocutaneous, and neurocutaneous.
What is the purpose of distant flaps?
Distant flaps involve free tissue transfer and are used when other types of flaps are not feasible.
What is the purpose of prelamination techniques in tissue reconstruction?
Prelamination techniques allow the creation of specialized flaps, such as using buccal mucosa.
What is tissue expansion in tissue reconstruction?
Tissue expansion involves the placement of tissue expanders to increase the amount of tissue at donor sites.
What is the size limitation for flaps in tissue reconstruction?
The size of flaps is limited by the territory of blood supply.
What is the main difference between skin grafts and flaps?
Skin grafts rely on the wound bed for blood supply, while flaps have their own blood supply and can survive independent of the wound bed.
What is the healing time for the donor site of a split skin graft?
The donor site of a split skin graft typically heals in 12 days and can be reused.
What are split thickness skin grafts?
Split thickness skin grafts are available in a range of thicknesses and are commonly taken from the thigh, which is the most common donor site.
What is the advantage of full thickness grafts in facial reconstruction?
Full thickness grafts, which include dermal appendages, provide a superior cosmetic result in facial reconstruction.
What are composite grafts used for in tissue reconstruction?
Composite grafts are used to cover small defects in cosmetically important areas and contain more than one tissue type, such as skin and fat.
What is the difference between pedicled and free flaps?
Pedicled flaps have their own blood supply but remain attached to the donor site, while free flaps are completely detached and require microvascular anastomosis.
Why are pedicled flaps less prone to failure compared to free flaps in breast surgery?
Pedicled flaps, such as the latissimus dorsi flap, have a more reliable blood supply compared to microvascular anastomosed free flaps like the DIEP flap in breast surgery.
What are surgical drains?
Surgical drains are inserted in many surgical procedures and can be divided into those using suction and those that do not.
What factors determine the diameter of a drain?
The diameter of the drain depends on the substance being drained, such as using a smaller lumen drain for pneumothoraces compared to haemothorax.
What complications can be associated with drains?
Complications associated with drains can occur during insertion, serve as a route for infections while in situ, and may cause other complications in specific situations, such as the risk of inducing fistulation when suction drains are left in contact with the bowel for long periods.
What types of drains are used in CNS procedures?
In CNS procedures, low suction drains or free drainage systems may be used for situations such as drainage of subdural hematomas.
What types of drains are used in CVS procedures?
In orthopaedics and trauma settings, drains are usually used to prevent hematoma formation, which is associated with a risk of infection. Some orthopaedic drains may also allow the drained blood to be autotransfused.
Why are abdominal drains commonly placed in gastrointestinal surgery?
In gastrointestinal surgery, abdominal drains are often placed to prevent or drain abscesses or to control anticipated complications, such as a bile leak following cholecystectomy. The type of drain used depends on the indication.