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.
What are the features of a Redivac drain?
Redivac drains are a type of suction drain and are part of a closed drainage system with a high-pressure vacuum system.
What are the features of low-pressure drainage systems?
Low-pressure drainage systems, such as the lantern-style drain, are used for short-term drainage of small wounds and cavities. Larger systems, used following abdominal surgery, have a lower pressure than the Redivac system to decrease the risk of fistulation. They can be emptied and re-pressurized.
What are the features of latex tube drains?
Latex tube drains can be shaped (e.g., T Tube) or straight and are usually used in non-pressurized systems as sump drains. They are often used to generate fibrosis along the drain track, such as following exploration of the common bile duct (CBD).
What are the features of chest drains?
Chest drains can be large or small in diameter, depending on the indication. They are connected to an underwater seal system to ensure one-way flow of air.
What are the features of corrugated drains?
Corrugated drains are thin, wide sheets of plastic that are usually soft and contain corrugations along which fluids can track.
What is abdominal wound dehiscence?
Abdominal wound dehiscence is a significant problem that occurs when all layers of an abdominal mass closure fail, causing the viscera to protrude externally. It is associated with a 30% mortality rate.
What are the two subdivisions of abdominal wound dehiscence?
Abdominal wound dehiscence can be subdivided into superficial, where only the skin wound fails, and complete, which implies failure of all layers.
What factors increase the risk of abdominal wound dehiscence?
Factors that increase the risk of abdominal wound dehiscence include malnutrition, vitamin deficiencies, jaundice, steroid use, major wound contamination (e.g., fecal peritonitis), and poor surgical technique. The preferred method is the mass closure technique, also known as the Jenkins Rule.
What is the management approach when sudden full dehiscence occurs?
When sudden full dehiscence occurs, the management approach includes analgesia, intravenous fluids, intravenous broad-spectrum antibiotics, coverage of the wound with saline-impregnated gauze, and arrangements made for a return to the operating theatre.
What is the surgical strategy for managing abdominal wound dehiscence?
The surgical strategy involves correcting the underlying cause, such as providing total parenteral nutrition (TPN) or nasogastric (NG) feed if malnourished, and determining the most appropriate strategy for managing the wound.
What are the options for managing the wound in abdominal wound dehiscence?
The options for managing the wound include resuturing the wound if the edges are healthy and there is enough tissue for sufficient coverage, applying a wound manager (clear dressing with removable front) when there is granulation tissue present or a high-output bowel fistula, using a ‘Bogota bag’ (clear plastic bag) as a temporary measure when the wound cannot be closed, and applying a VAC dressing system (negative pressure wound therapy) with the correct layer interposed between the suction device and the bowel to avoid complications.
What are diathermy devices used for?
Diathermy devices are used by surgeons in all branches of surgery to produce local heat using electric currents. This heat facilitates hemostasis (stopping bleeding) or surgical dissection.
What are some hazards of diathermy?
Some hazards of diathermy include inadvertent patient burn, which can occur due to careless handling of the device or forgetting to apply a return electrode plate in the case of monopolar devices. Additionally, there is a risk of explosion or fire when volatile anesthetic gases or skin preparation fluids are present.
How can patient burn be prevented in diathermy procedures?
To prevent inadvertent patient burn, it is important to handle the device carefully and ensure the proper application of a return electrode plate in monopolar devices.
What precautions should be taken to avoid explosion or fire during diathermy procedures?
To avoid explosion or fire, it is necessary to be cautious when volatile anesthetic gases or skin preparation fluids are used. Proper safety measures and protocols should be followed to minimize the risk.
What is primary closure?
Primary closure is a method of wound closure used for clean wounds, typically surgically created or following minor trauma. Standard suturing methods are usually sufficient, and the wound heals by primary intention.
In what situations is delayed primary closure used?
Delayed primary closure is used when primary closure is either not achievable or not advisable, such as in the presence of infection. The actual methods of closure for delayed primary closure are similar to those used for primary closure.
What is vacuum-assisted closure?
Vacuum-assisted closure is a method that utilizes negative pressure therapy to facilitate wound closure. A sponge is inserted into the wound cavity, and negative pressure is applied. This technique has advantages, including the removal of exudate and versatility. However, disadvantages include cost and the risk of fistulation if used incorrectly on sites such as the bowel.
What are split-thickness skin grafts?
Split-thickness skin grafts involve removing the superficial dermis with a Watson knife or dermatome, typically from the thigh. The remaining epithelium regenerates from dermal appendages. Meshing can be used to increase coverage.
What are full-thickness skin grafts?
Full-thickness skin grafts involve removing the whole dermal thickness. Subdermal fat is also removed, and the graft is placed over the donor site. This method provides better cosmesis and flexibility at the recipient site. However, it is associated with donor site morbidity.
What are flaps in wound closure?
Flaps refer to viable tissue with a blood supply that is used for wound closure. Flaps can be pedicled or free. Pedicled flaps are more reliable but have a limited range. Free flaps have a greater range but carry a higher risk of breakdown as they require vascular anastomosis.
How is superficial dermal bleeding managed?
Superficial dermal bleeding usually stops on its own, but if it persists, the use of monopolar or bipolar cautery devices can control the bleeding. In the case of scalp wounds, mattress sutures are often used as a wound closure method to address the bleeding.
What is the recommended method for managing superficial arterial bleeding?
If the vessel causing the superficial arterial bleeding can be safely identified, the easiest method is to apply a haemostatic clip and ligate the vessel.
How should major arterial bleeding be managed?
For major arterial bleeding, if the vessel can be clearly identified and accessed, a clip can be applied and the vessel ligated. If the vessel is located in a pool of blood, blindly applying haemostatic clips is dangerous, and it is safer to evacuate the clot and pack the area. The pack can be removed carefully when the required instruments are available. In some cases, bleeding from retracted vessels can be controlled by dissecting surrounding structures or under-running the bleeding point.
What is the initial course of action for managing major venous bleeding?
The safest initial course of action for major venous bleeding is to apply digital pressure to the bleeding point. The surgeon will need a working suction device to control the bleeding. Divided veins may require ligation, and incomplete lacerations of major veins, such as the inferior vena cava (IVC), are best repaired using a Satinsky type vascular clamp and 5/0 prolene for the repair.
What methods are useful for managing bleeding from raw surfaces?
Bleeding from raw surfaces can be troublesome and may involve mixed bleeding. Spray diathermy and argon plasma coagulation are useful agents for managing this type of bleeding. Additionally, topical haemostatic agents like surgicell can encourage clot formation and may be used in conjunction with or instead of the above agents.
What is an anastomosis?
An anastomosis refers to the restoration of luminal continuity and is commonly performed in both abdominal and vascular surgery. It involves the connection of two structures to allow the flow of fluid or blood between them.
What are the three criteria for a successful healing of an anastomosis?
For an anastomosis to heal, three criteria need to be fulfilled: adequate blood supply, mucosal apposition, and minimal tension. When these criteria are compromised, the anastomosis may break down.
Which types of anastomoses are more prone to leakage?
Oesophageal and rectal anastomoses are more prone to leakage, and reported leak rates following oesophageal and rectal surgery can be as high as 20%. However, it’s important to note that this figure includes radiological leaks, and clinically significant leaks will be of a lower order of magnitude. Small bowel anastomoses tend to heal most reliably.
What factors are more important than the method chosen for achieving mucosal apposition in anastomoses?
The attention to surgical technique is more important than the method chosen for achieving mucosal apposition in anastomoses. A poorly constructed stapled anastomosis in thickened tissue is far more prone to leakage than a hand-sewn anastomosis in the same circumstances.
What should be done if an anastomosis looks unsafe?
If an anastomosis appears unsafe, it may be best not to construct one at all. In colonic surgery, this decision is relatively clear-cut, and most surgeons would create an end colostomy instead. However, in situations such as oesophageal surgery, where anastomosis safety is more problematic, colonic interposition may be required.
What are some key points to consider for vascular anastomoses?
For vascular anastomoses, it is important to use non-absorbable monofilament suture (such as Polypropylene) and a round-bodied needle. The suture should be continuous and go from the inside to the outside of the artery to avoid raising an intimal flap. Additionally, the correct size of suture should be used for the specific anastomosis being performed. For example, a 6/0 prolene suture may be suitable for the bottom end of a femoro-distal bypass.
What are the three processes involved in the sterilization of surgical equipment?
The three processes involved in the sterilization of surgical equipment are cleaning, disinfection, and sterilization.
What does the process of cleaning involve?
Cleaning refers to the removal of physical debris from the surgical equipment. It is the first step in the sterilization process.
What is the purpose of disinfection?
Disinfection aims to reduce the number of viable organisms on the surgical equipment. It is an important step in ensuring the cleanliness and safety of the equipment.
What does sterilization involve?
Sterilization is the complete removal of all organisms and spores from the surgical equipment. It ensures that the equipment is free from any potential sources of infection.
What is glutaraldehyde solution used for?
Glutaraldehyde solution, a colourless oily liquid, is specifically used for sterilizing endoscopes and some laparoscopic items. It is directly cytocidal and virucidal even at low temperatures. However, it should be noted that staff can develop allergies to this substance, which has limited its more widespread use.
What is autoclaving and when is it typically used?
Autoclaving involves the use of high-pressure steam at a specific temperature (usually 134°C for 3 minutes) to sterilize reusable surgical equipment. It is commonly used for equipment that can withstand heat and pressure, but may not be suitable for fragile items.
What is gamma irradiation used for and how does it work?
Gamma irradiation involves the use of gamma rays emitted from radioactive substances such as cobalt 60 or caesium 137. It is suitable for batch treatment of relatively thermostable items. This method of sterilization is typically used in industrial processes.
When is ethylene oxide used for sterilization?
Ethylene oxide is used for sterilizing packaged materials that cannot be heated. It is a 3% mixture of gas with carbon dioxide. However, it is important to note that ethylene oxide gas is explosive and environmentally toxic, so it is primarily used in industrial settings.
What does Level I evidence refer to?
Level I evidence refers to evidence obtained from a systematic review of all relevant randomized controlled trials. It is considered the highest level of evidence.
What does Level II evidence refer to?
Level II evidence refers to evidence derived from at least one properly designed randomized controlled trial.
What does Level III evidence refer to?
Level III evidence refers to evidence derived from well-designed pseudo-randomized controlled trials (such as alternate allocation) or historical controls.
What does Level IV evidence refer to?
Level IV evidence refers to evidence derived from case series or case reports.
What does Level V evidence refer to?
Level V evidence refers to panel or expert opinion. It is the lowest level of evidence and is based on the professional judgment and expertise of a panel of experts in the field.
What gas is commonly used for insufflation in laparoscopic surgery?
Carbon dioxide gas is commonly used for insufflation in laparoscopic surgery.
Why is the amount of gas delivered adjusted during laparoscopic surgery?
The amount of gas delivered is adjusted to maintain a constant intra-abdominal pressure of between 12 and 15 mmHg.
What are the consequences of excessive intra-abdominal pressure during laparoscopic surgery?
Excessive intra-abdominal pressure can reduce venous return, leading to hypotension (low blood pressure).
What are the risks of too little insufflation during laparoscopic surgery?
Too little insufflation can risk obscuring the surgical view, making it difficult for the surgeon to see and perform the procedure effectively.
What are surgical site infections (SSI)?
Surgical site infections (SSI) occur when there is a breach in tissue surfaces during surgery, allowing normal commensals and other pathogens to initiate an infection. They are a significant cause of morbidity and mortality.
What percentage of healthcare-associated infections do surgical site infections comprise?
Surgical site infections (SSI) comprise up to 20% of all healthcare-associated infections.
What percentage of patients undergoing surgery will develop a surgical site infection?
At least 5% of patients undergoing surgery will develop a surgical site infection as a result.
Where do the organisms causing surgical site infections usually come from?
In many cases, the organisms causing surgical site infections are derived from the patient’s own body.
What are some measures that may increase the risk of surgical site infections?
Some measures that may increase the risk of surgical site infections include shaving the wound using a razor (a disposable clipper is preferred), using a non-iodine impregnated incise drape if necessary, tissue hypoxia, delayed administration of prophylactic antibiotics in tourniquet surgery, and routine removal of body hair.
When is antibiotic prophylaxis recommended for surgical site infections?
Antibiotic prophylaxis is recommended for surgical site infections in cases such as placement of prosthesis or valve, clean-contaminated surgery, and contaminated surgery. The use of a local formulary and aiming to give a single dose of IV antibiotic on anesthesia are important considerations. If a tourniquet is to be used, prophylactic antibiotics should be given earlier.
What measures should be taken intraoperatively to prevent surgical site infections?
Intraoperatively, the skin should be prepared with alcoholic chlorhexidine, which has the lowest incidence of surgical site infections. The surgical site should be covered with a dressing. It has been confirmed through meta-analysis that administration of supplementary oxygen does not reduce the risk of wound infection. Additionally, the use of wound edge protectors does not appear to confer a benefit.
What is the advice for managing surgical wounds healing by secondary intention postoperatively?
Postoperatively, tissue viability advice should be followed for the management of surgical wounds healing by secondary intention.
What is the controversy regarding the use of diathermy for skin incisions in surgical site infections?
In the NICE guidelines, the use of diathermy for skin incisions is not advocated. However, several randomized controlled trials have been undertaken and demonstrated no increase in the risk of surgical site infection when diathermy is used.
What is the purpose of creating a pneumoperitoneum during a laparoscopic procedure?
The purpose of creating a pneumoperitoneum during a laparoscopic procedure is to induce a working space in the abdominal cavity.
What are the methods to achieve pneumoperitoneum?
Pneumoperitoneum can be achieved using a Verress needle, although there is a risk of visceral injury. An alternative method is the open ‘Hassan’ style technique.
What gas is used to insufflate the abdominal cavity during a laparoscopic procedure?
Carbon dioxide gas is used to insufflate the abdominal cavity during a laparoscopic procedure.
What are the potential complications of higher intra-abdominal pressures during pneumoperitoneum?
Higher intra-abdominal pressures can compromise venous return and reduce cardiac output. If blood pressure drops as a result, releasing air from the abdominal cavity can often improve the situation.
What should be done if releasing air does not improve the drop in blood pressure during a laparoscopic procedure?
If releasing air does not improve the drop in blood pressure, a laparotomy (open surgery) may be necessary to exclude a more significant internal injury.
What are some presenting features of Hodgkin’s lymphoma?
Some presenting features of Hodgkin’s lymphoma include asymptomatic lymphadenopathy, cough, Pel-Ebstein fever, haemoptysis, dyspnoea, and B symptoms such as 10% weight loss, fever, and night sweats.
What staging system is commonly used for Hodgkin’s lymphoma?
The Ann Arbor staging system is commonly used for staging Hodgkin’s lymphoma.
What are the stages of Hodgkin’s lymphoma according to the Ann Arbor staging system?
According to the Ann Arbor staging system, the stages of Hodgkin’s lymphoma are as follows: Stage I - involvement of a single lymph node region, Stage II - involvement of two or more regions on the same side of the diaphragm, Stage III - involvement of lymph node regions on both sides of the diaphragm, and Stage IV - involvement of extra nodal sites.
What are the subtypes of classical Hodgkin’s lymphoma?
The subtypes of classical Hodgkin’s lymphoma are nodular sclerosing Hodgkin lymphoma (NSHL), mixed-cellularity Hodgkin lymphoma (MCHL), lymphocyte-depleted Hodgkin lymphoma (LDHL), and lymphocyte-rich classical Hodgkin lymphoma (LRHL).
What is the link between Hodgkin’s lymphoma and Epstein-Barr virus?
Infection with Epstein-Barr virus is linked to the development of Hodgkin’s lymphoma, particularly in cases of mixed-cellularity lymphoma.
How is the diagnosis of Hodgkin’s lymphoma made?
The diagnosis of Hodgkin’s lymphoma is made by excision of a complete lymph node, which is then submitted for detailed histological evaluation.
What is the prognosis of Hodgkin’s lymphoma?
Stage I disease is associated with survival figures of up to 85% at 5 years. Nodular sclerosing Hodgkin’s lymphoma has the best prognosis. Lymphocyte-depleted Hodgkin’s lymphoma, advancing age, male sex, and stage IV disease are all associated with a worsening of prognosis.
What are the treatment options for Hodgkin’s lymphoma?
Treatment for Hodgkin’s lymphoma may be multimodal, involving both chemotherapy and radiotherapy.
What is the purpose of randomized controlled trials?
Randomized controlled trials are conducted to compare two variables, such as treatments or treatment versus placebo, in order to determine their effectiveness.
What is the ideal condition for randomized controlled trials?
Ideally, randomized controlled trials should be blinded, meaning that the patients and the individuals involved in their treatment are unaware of which variable they are receiving.
How is a fistula defined?
A fistula is defined as an abnormal connection between two epithelial surfaces.
Why is a power calculation necessary in randomized controlled trials?
A power calculation is performed in most cases to determine the sample size required for a randomized controlled trial to effectively detect a difference between the variables being compared.
What is a common cause of abdominal fistulas?
In general surgical practice, the majority of abdominal fistulas arise from diverticular disease and Crohn’s disease.
What are some examples of different types of fistulas?
Examples of different types of fistulas include branchial fistulae in the neck, entero-cutaneous fistulae abdominally, enterocutaneous fistulae, enteroenteric or enterocolic fistulae, enterovaginal fistulae, and enterovesical fistulae.
Under what conditions will fistulas usually resolve spontaneously?
As a general rule, all fistulas will resolve spontaneously as long as there is no distal obstruction. This is particularly true for intestinal fistulas.
What are the four types of fistulas?
The four types of fistulas are enterocutaneous, enteroenteric or enterocolic, enterovaginal, and enterovesical.
What is the management approach for fistulas?
Some management approaches for fistulas include conservative measures if there is no underlying inflammatory bowel disease and no distal obstruction, protecting the overlying skin in cases of skin involvement, considering the use of octreotide for high output fistulas to reduce pancreatic secretions, addressing nutritional complications with high fistulas by using TPN (total parenteral nutrition) and octreotide, avoiding probing perianal fistulas when acute inflammation is present, draining acute sepsis and maintaining drainage through setons for perianal fistulas secondary to Crohn’s disease, and attempting to delineate the fistula anatomy through imaging studies.
What is Goodsall’s rule in relation to perianal fistulas?
Goodsall’s rule is a principle used to determine the internal and external openings of perianal fistulas.
What is the main hormone secreted by carcinoid tumors?
Carcinoid tumors primarily secrete serotonin.
Where do carcinoid tumors mainly originate?
Carcinoid tumors mainly originate in neuroendocrine cells in the intestine, particularly the midgut (distal ileum/appendix). They can also occur in the rectum and bronchi.
When do hormonal symptoms of carcinoid syndrome typically occur?
Hormonal symptoms of carcinoid syndrome typically occur when the disease spreads outside of the bowel.
What are some clinical features of carcinoid syndrome?
Clinical features of carcinoid syndrome include an insidious onset over many years, flushing of the face, palpitations, pulmonary valve stenosis and tricuspid regurgitation causing dyspnea (shortness of breath), asthma, and severe diarrhea that is secretory in nature and persists despite fasting.
What investigations are commonly performed for carcinoid syndrome?
Common investigations for carcinoid syndrome include measuring 5-HIAA (a metabolite of serotonin) in a 24-hour urine collection, somatostatin receptor scintigraphy, CT scan, and blood testing for chromogranin A.
What are the two commonly employed measurements of variability?
The two commonly employed measurements of variability are the standard deviation and the interquartile range.
What is the treatment for carcinoid syndrome?
The treatment for carcinoid syndrome includes the use of octreotide, a medication that inhibits hormone secretion. Surgical removal of the tumor may also be considered.
What are some examples of point estimates in descriptive statistics?
Examples of point estimates in descriptive statistics include the mean, median, and mode.
How is the standard deviation typically considered?
The standard deviation is usually considered in association with the mean.
What are some other measures of data variability?
Other measures of data variability include the standard error of the mean and confidence interval.
What is the interquartile range used alongside?
The interquartile range is used alongside the median.
When should the standard error of the mean be used?
The standard error of the mean should be used when describing the characteristics of more than one sample. It represents the measure of variation around the point estimate of the mean of a group of sample means.
