General Surgery: Modern Techniques & Preoperative Evaluation PDF

GENERAL SURGERY Prof. Viganò Lesson 1- Modern surgery: an overview Surgery: medical specialty that uses manual and/or instrumental techniques to physically reach into a subject’s body to investigate or treat pathological conditions, such as disease or injury, altering bodily functions. It also inclu...

GENERAL SURGERY Prof. Viganò Lesson 1- Modern surgery: an overview Surgery: medical specialty that uses manual and/or instrumental techniques to physically reach into a subject’s body to investigate or treat pathological conditions, such as disease or injury, altering bodily functions. It also includes procedures such as endoscopy which can be surgical but are not performed by surgeons. Classification of surgeries: they can be classified: - according to the organ that needs to be treated, - by aim (diagnostic/explorative, reconstructive, curative/palliative, preventive, transplant) - by timing (a UK definition which divides immediate emergency surgery from urgency 1 , expedited, elective surgery) Surgical terminology: Laser surgery - you can remove some lesions by laser. Cryosurgery - uses low-temperature cryo-ablation to freeze and destroy some targets. Microsurgery- works with the operating microscope. This can be used, for example, in neurosurgery sometimes. Endoscopic surgery: Endoscopic surgery is a minimally invasive surgery (not the case of gastroscopy or colonscopy). The standard endoscopic surgery is laparoscopy. Laparoscopy is a technique in which you reduce the size of the incision (the percentage of procedures that we perform by laparoscopy is increasing). If I must perform a colonic resection, the standard approach is a laparotomy with a midline incision of about 20 centimeters at least; laparoscopy replaces the skin incision by doing small incisions, from which you enter the peritoneum and put a cannula. From this cannula, you inflate to put some gas into the peritoneum and create a camera. In the end, the abdomen will be dilated and inflated, so that the peritoneum is distended, and the organs are below. Then you put some other cannulas (possibly through other incisions) to which you put your instruments. You will work looking at the screen. Then you will remove the specimen through an extra incision or by enlarging an existing one or something like that. A good example is laparoscopic cholecystectomy. The standard incision for cholecystectomy was a right subcostal incision. Now you perform a one-centimeter incision at the umbilicus and two or three other five-millimeter incisions and then you extract the gallbladder through the umbilicus. How to extract the colon in colonic resection? Through a Pfannenstiel incision that is like a cesarean section, you have this strong cosmetic advantage. In addition, you have less adhesions, because you have less trauma on internal organs, a faster recovery to normal function and less postoperative pain. Robotic surgery: the idea is the same as laparoscopy, the only difference is that you use a robotic platform to remotely control the instruments that enter through minimally invasive approaches. I have a console where I work, and I control the instruments that the machine moves according to my instructions. There are several advantages in terms of vision, precision, and quality of movements. Robotic surgery will probably be the future of medicine - being the starting point for automated procedures - but we don't know in how many years because there are still some limitations to be worked on. When you work with the robot you may integrate artificial intelligence and protocols There is some advanced research in which the machine is performing an automatic identification of the anatomical structures - the first step is to section the structure in an automatic process. There are some experiments in which the machine performs some anastomosis. (suture to connect to hollow organs) - very preliminary since we are far from the standard application of that. Prof. Viganò 1 They split the urgent surgery in urgency and expedited. 1 Lecture 2 – Principles of surgical evaluation & frail patients and rehabilitation The acceptable mortality rate to perform surgery today is 0.1. That is of course a general definition, as the mortality rate of course changes depending on the operation: for a hernia it should be 0%, for colorectal K (cut the bowel and perform a manual anastomosis) it could be a little higher. In general, however, surgery had major improvements in its results, also in complicate procedures, therefore in any case the only accepted mortality rate is very close to zero. When the mortality rate is higher, the decision to perform surgery or not is made also taking into consideration the expectancy and quality of life without operation. Another case is an emergency situation in which the rate of mortality is not so important anymore, an example is acute bowel ischemia for which if the patient is not operated he will develop peritonitis and die. Which are the steps before deciding to perform a surgery? Confirm diagnosis Confirm surgical indication Define the most appropriate type of procedure Assess the risks Preoperative risk assessment It means making a balance between the risks and the benefits, deciding if surgery can improve the quality/expectancy of life. Moreover the patient may or may not be eligible for a certain surgery because of their comorbidities, which may affect the outcome of the surgery itself or the reaction to anaesthesia. Most patients just receive a general evaluation composed of an ECG, blood counts, renal function and glucose level. Then according to specific conditions, other additional evaluations can be performed2. Criteria to select if a patient is a good candidate for a surgical operation The ASA score (American Society of Anaesthesiology) is a preliminary score for evaluating the anaesthesiologic risk of a patient. It goes from I to VI3 , in category II there are patients with mild disease, pregnancy and obesity. You may add the letter “E” for any emergency operation and this may change the evaluation. In any case, you often need a more detailed evaluation. Cardiac evaluation4 : there are several ways to assess the score, the first (1977) consisted of a list of cardiac conditions and each would have a certain score. Now the Cardiac Risk Index has been revised and simplified, and each cardiac condition has a score of “1”; for each point added the risk for postoperative myocardial comorbidity increases. The Revised Cardiac Risk Index contains: Ischemic heart disease Congestive heart failure Cerebral vascular disease High-risk surgery Preoperative insulin treatment for diabetes Preoperative creatinine level >2 mg/dL 2 Remember that every evaluation is an expense and is time consuming, so the type and quantity of tests need to be chosen “wisely”. 3 Even if subjective, this evaluation proves to have a strict association with the mortality rate, which increases along the score. 4 First and most important evaluation. 2 The “Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery” were published in 2007 and they are still used as the rules to evaluate the patient: Step 1: if it is an emergency you go with it, independently from the cardiac problem. Step 2: if it isn’t an emergency, you need to consider whether the patients has an active cardiac condition (unstable coronary disease, decompensated heart failure5 , significant arrhythmias, severe valvular disease). If the answer is yes, you need to solve these problems before performing the surgery, also in case of cancer. Step 3: in case of no active condition, you consider the kind of surgery, because if it is a low risk one you can simply go ahead. Step 4: in case of higher risk an evaluation of the CV function must be done. A simple one is MET, which is the evaluation of the metabolic state of your patient and describes the amount of energy needed to perform certain daily tasks. Every daily activity has a score based on its intensity; you calculate the MET score of the patient depending on the activities they perform throughout the day. If the MET< 4, you have to consider the patient having some underlying CV condition. Step 5: therefore, in case of underlying CV conditions (or if they are unknown), you must investigate if the patient has one or more Cardiac risk index conditions. Pulmonary evaluation: Smoking, COPD, preoperative sputum production, pneumonia, dyspnoea and obstructive sleep apnoea are conditions that can worsen the outcome of surgery, therefore these problems need to be solved before the surgery. You should also try to reduce the pulmonary impact during the surgery (like performing epidural anesthesia) and afterward by doing pulmonary rehabilitation. Kidney evaluation: About 5% of the adult population has some renal dysfunction. Creatinine level >2 mg/dL leads to an increased risk of postoperative cardiac complications. Liver evaluation: liver cirrhosis significantly impacts the outcomes and mortality rate, but still it is not an absolute contraindication for surgery: you need to select the patients using two scores, Child Pugh and MELD scores. The former has 5 parameters (Bilirubin, Albumin, INR, Ascites and Encephalopathy) and for each a score from 1 to 3 is assigned. According to the overall score the patient is put into class A (5-6), B (7-9) or C (10-15). Only class A patients are allowed to undergo surgery in 99% of cases. Moreover, portal hypertension is an additional complication for the surgery outcome. In real life, besides Child Pugh other criteria are considered (scintigraphy, liver stiffness etc). Beyond cirrhosis other factors related to the kidney must be 5 NYHA functional class IV, worsening or new onset HF. 3 considered: there is a risk of unexpected liver injury, associated with chemotherapy, obesity and metabolic syndrome, so these are considered major risk factors. Endocrine and Immune system: risk factors are diabetes, thyroid problems6 and chronic steroid therapy. Regarding the immune system it is important to understand if the patient is taking antineoplastic drugs, immunosuppressive therapy, has AIDS or other immunosuppressive disease. Haematological disorders: anaemia is very common and must therefore be investigated, also considering its cause (of related to the disease that is bringing the patient in the OR or not). Also coagulopathy must be considered but the problem is that it may be very difficult to detect. You investigate if there is a history and the platelet count (if it is < 50 x 10*3/mL). Other factors: age is not a discriminative to exclude a patient from surgery but of course there will be more comorbidities in older patients. The perioperative mortality risk is increased in patients with severe obesity (BMI>40 kg/m2) or BMI>35 kg/m2 with comorbidities. For obese people there is also an increased risk for post-op wound infections, deep vein thrombosis, and pulmonary embolism. For medications, according to the drugs there are different timing of stopping or replacing: Beta-Blockers should not be stopped Metformin may lead to an increased risk of lactic acidosis Antithrombotic therapy (e.g. Warfarin) should be stopped 5 days before, and according to guidelines you should restart again with the drug the same night after the operation since the drug supposedly takes a few days before being effective, but in reality the surgeons wait a couple of days before restarting the medication since they’re worried about bleeding. Acetylsalicylic acid doesn’t have to be stopped before surgery anymore Ci sono 3 clinical example tra pag 4 e 5 della sbobina 2. How to reach a global risk assessment? The American College of Surgeons made an online calculator that considers the type of procedure you’re performing and 20 clinical parameters on the patients and it will predict the patient risk factors. It a good predictor, but of course not perfect: it still cannot take into account the complexity of the parameters. Frailty It is a state of reduced physiological capacity and increased susceptibility to disability caused by age-related loss of physical, cognitive, social and psychological function and it can significantly change the outcome of the surgery. state of reduced physiological capacity and increased susceptibility to disability caused by age- related loss of physical, cognitive, social and psychological function. Frailty is a multi-factorial event, given by age, chronic comorbidity, disability. All these factors are not alone sufficient for a frailty diagnosis but must be considered together. NB: frailty is a spectrum, not an individual condition. We grade frailty in two ways: physical frailty (defines patient according to S&S), index frailty (considering cumulative comorbidities and illnesses). Physical frailty: S&S taken into account are: Weight loss Exhaustion Weakness Slow walking speed Decreased physical activity A patient is frail it at least 3 of these are present. There is also the FRAIL scale (acronym). Each affirmative answer to these questions is worth 1. 6 Not necessary to check in every patient. 4  Fatigue: have you felt fatigues? Most or all the time over the past month? Resistance: do you have difficulties climbing a flight of stairs? Ambulation: any difficulties walking one block? Illnesses: diabetes, hypertension, cancer, chronic lung disease, heart attack, congestive hert failure, angina, asthma, arthritis, stroke, kidney disease? Loss of weight: have you lost more than 5% of your weight in the past year? The patient is defined pre-frail when the score is 1-2 and frail when the score is >3. Index Frailty: consider all of the comorbidities, using a comprehensive geriatric assessment, even though this is time-consuming and multidisciplinary. The assessment takes into consideration: functional status of the patient, diabetes, history of COPD, history of congestive heart failure and hypertension requiring medication. Independently from the scale used, when the patient is frail, intraoperative mortality is increased, since the patient has much less “reserve” to recover from complications. Sarcopenia: is the age-related loss of skeletal muscle mass, muscle strength and muscle function. More than 50% of patients > 80 yrs old are in this condition, but also a large percentage of patients of any age that are affected by oncological diseases. It is associate with more complications, higher mortality and longer hospital stay. It can be assessed through physical tests or through imaging (CT and MRI). Prehabilitation: consists in preparing the patients in the perioperative setting to have better outcomes in surgery. It includes: Nutritional assessment and supplementation Tell the patient to stop smoking Physical exercise programs Take care of cognitive function and stress The ERAS protocol is a way to reduce the stress response to surgery, while prehabilitation occurs before. Improving nutritional status of the patient can improve surgery outcomes (consider that both surgery and cancer have a bad impact on the nutritional status of the patient). The patient might be eating less than usual and/or he may have albumin < 3, in these cases the malnutrition can be solved by giving supplementation usually orally or enterally, but possibly in severe malnourishment also parenterally. Moreover, in severely malnourished patients 10-14 days of nutrition support is recommended, but also for all patients undergoing GI oncological surgery it should be considered to give about 7 days of immunonutrition (→ nutritional formulas aimed to regulate the activity of the immune system). Immunonutrition seems to reduce postoperative infections. Smoking cessation seems to have a high impact, and in COPD patients you may also teach breathing techniques and give medications. You may correct anemia with iron supplementation, or with erythropoiesis stimulation (if it doesn’t interfere with the cancer). Blood transfusions should be considered only in the event of severe anemia with risk of organ ischemia. Telerehabilitation can be used to contact the patient remotely to provide prehabilitation and to monitor his activity and psychological aspect. Prof. Viganò Lecture 3 – Principles of surgical oncology The evolution: there is an important (obvious) distinction between the surgeon and the surgical oncologist. The concept has evolved from “one size fits all”, which is sometimes still used, to a patient-specific and cancer- specific approach, to have a more precise medical and surgical approach to the patient. 5 Surgeons are frequently the first specialists involved with most solid tumors. This means surgeons have to be familiar with all aspects of the diseases – as they are not only technicians performing a surgery – and to deal with diagnosis via imaging, pathological data, staging, patient-selection, prognostic factors, specific surgical techniques, and therapeutic alternatives. The aims of surgery: surgery can be curative (the most important one regarding oncology), debulking or palliative. It can also have diagnostic or staging roles. (plus supportive, restorative, prophylactic). Step 1 – The diagnosis: you can start with imaging, then carry on with biopsy, which should confirm the tumor type, the grade, show the lympho-vascular invasions. In some cases, special immunohistochemical stains may be performed to assess hormone receptor status – such as in breast cancer – or flow cytometry may be performed to assess subtypes such as in lymphoma. Mutational status can be evaluated as well. Even though having a biopsy beforehand is always a good idea, therer are cases in which you can’t really perform it (for instance if you have a stenosis of the bile duct confluence, very difficult to reach, you perform ERCP, difficult operation with low sensitivity). Another exception is in the diagnosis of hepatocellular carcinoma in cirrhotic patients undergoing a follow-up. If you have a new lesion, in the arterial phase of a CT or MRI scan it is seen as hyperdense, while in the portal phase, it returns hypodense. The tumor is said to have a “wash-in, wash-out” reaction which in this case of HCC in cirrhotic patients is sufficient to have a diagnosis. Ha riportato un caso a pagina 3 di dubbia importanza ma vedete un po’ voi. In the following images there are very two realy similar cases, both presententi to the ER with acute abdominal pain. In both cases the imaging showed black bubbles, air outside of the colon. The colonic wall has thickened and you cannot see the lumen anymore. This findings suggest diverticulitis. Cas2 was indeed diverticulitis, but case 1 was a perforated cancer. Only endoscopy could give the final diagnosis. In emergency settings you may be forced to operate without proper diagnostic tools (either endoscopy or biopsy) but the prognosis may be worse and generally it more difficult. Different types of biopsy: Needle biopsy: fine-needle aspiration (cytology) and core needle biopsy. Endoscopic biopsy (in case of colonic or gastric thickening) Surgical biopsy (incision and excision7 ). Management of benign lesions: they may represent borderline diseases. You need to consider ig there is any risk of progression, so they need follow-up. Surgery must be performed: if the lesion is precancerous (like colonic polyps); if the lesion is symptomatic; if the lesion has an uncertain diagnosis (prognosis is uncertain); 7 for example if we are not sure if a lesion is a melanoma, we can decide to remove all of it and wait for the diagnosis after surgery; according to the final diagnosis and the pathology report, you will decide if the patient will have to undergo another surgery to remove some lymph nodes. 6  if the lesions has modifications detected during a follow-up. Again un caso che non ho capito a che cazzo servisse. Step 2 – Staging: to perform in case of malignancy, by defining the extension of the disease locally and distally, also including some tumor markers. You use the TNM classification, which has 3 parameters to consider, each with sub-parameters: T: size or direct extent of the primary tumor: a. Tx: tumor cannot be assessed. b. Tis: carcinoma in situ. c. T0: no evidence of tumor; this is really important, and it is for example the stage after chemotherapy or radiotherapy, when you can’t find anything else. d. T1, T2, T3, T4: size/extension of the primary tumor. N: degree of spread to regional lymph nodes: a. Nx: lymph nodes cannot be assessed; it could be an index of poor quality surgery, as it means that either there were no lymph nodes or there weren’t enough lymph nodes because you need a minimal number to be sure that we can state the patient is N0. In some cases, Nx patients have a worse prognosis than N0 ones, because we are understaging the disease. b. N0: no regional lymph nodes mets. c. N1 (in some cases N2, N3): regional lymph nodes mets. M: presence of distant metastases8 : a. M0: no distant metastases. b. M1: metastasis to distant organs (beyond regional lymph nodes). Example: breast cancer. By combining the parameters, you can have the tumour stage: Stage 0: carcinoma in situ (TisN0M0) Stage 1-2: tumors localized in the organ (T1-4N0M0) Stage 3: tumors with lymph node mets (anyT, N+M0) Stage 4: tumors with distant metastasis (anyT, anyM, N+) An example of TNM application - Colorectal cancer: in this case, you need 12 lymph nodes not to be an Nx. Then you have a classification according to the number of lymph nodes and the spreading across the organs (e.g.: N1a → metastasis to 1 organ; N1b → metastasis to 2-3 organs...), because studies are predicting different outcomes according to that9. Gallbladder K example: about 1% of patients who have a cholecystectomy for gallbladder stones may have the incidental diagnosis of gallbladder cancer. The patients are then treated according to the T: If it is an in situ tumor (Tis or T1a in the lamina propria) cholecystectomy is enough. If it is a T1b tumor, you have a risk of 10-15% of tumor metastasis, so you have to operate on the patient. If it is a T2 or more, you have to perform an extended cholecystectomy with lymph nodes dissection. Metastases can spread via blood, the lymphatic system, via trans coelomic route (into body cavities, such as the peritoneum), and via canalicular spread (along anatomical canalicular spaces, such as bile ducts, the urinary system, the airways...). Each tumor can behave in different ways and haver different tropism, therefore each tumor has different probabilities of giving metastases in different organs. 8 In each tumor you have locoregional lymph nodes; if you have the presence of positive lymph nodes outside the locoregional ones, you have a metastasis. 9 In case of liver mets, 50% of pt undergoing surgery, with chemo and radio are alive after 5 yrs. 7 Before TNM, you can sometimes find a prefix which specifies the characteristics of staging: cTNM: c stands for clinical, so the TNM is based on preoperative evaluation (including clinical examination, imaging, endoscopy, biopsy, and surgical exploration); the c-prefix is implicit in the absence of the p-prefix. pTNM: based on pathology data. yTNM: stage after chemo/radiotherapy. rTNM: stage for a recurrent tumor. aTNM: stage determined at autopsy. uTNM: stage based on ultrasound or endoscopic ultrasound. mTNM: in case of multiple tumors. You can also find additional parameters in addition to TNM: G (1–4): tumor grading. S (0–3): elevation of serum tumor markers. Pn (0–1): perineural invasion. L (0–1): lymphatic vessel invasion. V (0–2): venous invasion (no, microscopic, macroscopic). Surgery can also have a role in diagnosis and staging: besides incisional and excisional biopsy, there is also exploratory laparoscopy, in which you explore the abdomen to find metastases that are difficult to visualize with imaging (eg. peritoneal mets) and you asses their extent. Again a case. Step 3 – The multidisciplinary team: physicians of different specialty meet to discuss surgery and different therapeutic approaches and the palliative therapies if the prognosis is poor. Different actors are playing in the team, then there might be some additional ones who are experts on a disease depending on which the problem is. Step 4 - The surgery: No- touch technique: old-fashioned assumption with no evidence, based on the concept that the manipulation of the tumor can lead to an increase in local implantation and embolization of tumor cells. Theoretically, the metastatic potential of the primary lesion would be enhanced by the mechanical extrusion of tumour cells into local lymphatic and vascular spaces. Surgical margins: Oncological surgery aims at removing the cancer with adequate margins of normal tissue. This is because all around the tumor you can find some satellite nodules, microvascular invasion and other tumor cells that lead to a local relapse. Clear margins have an impact on local control (local recurrence risk) and even survival. Adequate margin width differs according to the tumor. In some cases, you may have to consider additional margins10. In selected cases, the surgeon may ask for an intraoperative evaluation of the margin status by the pathologist (frozen section). If a margin is positive, resection can be extended, if feasible. When defining the margins, we consider the R status, which corresponds to the completeness of surgery: 10 For example, the mesorectum is the fat tissue between the sacrum and the rectum, and when you remove a tumour in this area you have to consider not only the distal and proximal margins, but also a circumferential margin (depending on how far the tumour is from the fascia surrounding), and this is associated to the prognosis. 8  a. R0: clear margins, no residual disease. b. R1: margin