Anesthesiology

Hind quarter amputation

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What the Anesthesiologist Should Know before the Operative Procedure?

Hemipelvectomy is a major surgical operation. When a tumor is not able to be resected with the use of a limb-sparing technique or via hip disarticulation, a hemipelvectomy may be required. In this procedure, the lower extremity and much of the bony pelvis are removed. This is also known as an external hemipelvectomy. Disarticulation frequently occurs at the level of the pubic symphysis and the sacroiliac joint. An internal hemipelvectomy may be performed in appropriate candidates. This is a limb-sparing or limb-salvage procedure that involves saving the patient’s limb while resecting areas involved with the tumor. Given the importance of an adequate and tumor free surgical resection in the long-term outcome of patients, hemipelvectomy remains a potentially curative surgical method.

As a hemipelvectomy is a major surgical procedure, it is not surprising that initial surgical attempts resulted in patient death, and it was not until 1895 that Girard performed the first successful hemipelvectomy. Now with improved surgical technique, along with the advances in anesthesia, hemodynamic monitoring, fluid management, hemostasis, and the ability to provide packed red blood cells (PRBCs) and clotting factors as necessary, survival for patients undergoing this procedure has improved.

The incidence of hemipelvectomy has decreased as a result of more effective cancer therapy and use of limb salvage procedure. Furthermore, the development of non-orthopedic fields including management methods as early diagnosis and follow-ups by imaging, new chemotherapy and/or radiation therapies, and implants or bioengineering have led to improvement in the outcomes of hemipelvectomies. Reconstruction after hemipelvectomy has also led to better outcomes and quality of life for patients. Reconstructive plastic surgery techniques, such as free flaps, have improved reconstruction, in addition to helping reduce infection rates.

Procedures for hemipelvectomy depend on tumor involvement and resectability. The hemipelvectomy that is limb-sparing is referred to as an internal hemipelvectomy.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

The answer to this question depends on the indications for surgery. Procedures performed for tumor surgery are usually not urgent or emergent, but need to be performed to resect tumor. Trauma, vascular insufficiency, infection, or bleeding may result in the procedure becoming urgent or emergent.

Emergent

Emergent indications for this major surgical procedure carry an associated high morbidity/mortality.

a. Trauma-bleeding: Life threatening blood loss with profound hemodynamic instability

b. Acute arterial insufficiency: Due to new-onset ischemia secondary to acute arterial occlusion

c. Severe infections: On patients showing signs of imminent septic shock (hypotension, tachycardia, decreased systemic vascular resistance [SVR])

Urgent

a. Infections: Trying to address source of infection before the patient becomes hemodynamically unstable

b. Chronic vascular disease

Elective

a. Tumor resection.

2. Preoperative evaluation

The challenge of anesthetic management for a patient undergoing hemipelvectomy is the potential for massive blood loss, which at times may become difficult to control and may result in hypotension and coagulopathy. Extensive tissue trauma and fluid resuscitation can result in third spacing of fluids and edema. Postoperative pain management is also a challenge, as there is significant pain associated with the procedure, including the potential development of phantom limb pain.

As the patient may have received medical treatment including chemotherapy prior to the procedure, it is important that they are adequately evaluated for cardiac, respiratory, hematologic, and neurologic issues prior to their surgery. Routine laboratory results including complete blood count (CBC), liver function tests (LFTs), coagulation profile. Specific patient specific issues need to be addressed. Cardiac work-up may be required based on the chemotherapy given. Echocardiogram may be indicated.

The anesthesiologist must be prepared that he/she is undertaking a surgical procedure associated with significant blood loss, which can be rapid at times. Communication with the surgeon prior to the procedure can help the anesthesiologist in preparing for the amount of blood loss expected during surgery. The intra- and postoperative blood transfusion requirements appear to be related to the type and extent of the surgical reconstruction. For instance, in procedures where pelvic stability is the goal, blood loss will likely be less than those procedures in which pelvic stability is not the surgical goal. Blood loss can range from 400 to 12,000 ml or more. It is not uncommon as a result of rapid blood loss that hemodynamic instability occurs. The blood bank should be aware of the potential needs and have multiple units cross-matched.

Medically unstable conditions warranting further evaluation include:

Cardiac: Acute coronary syndrome, unstable angina, new-onset arrhythmia, congestive heart failure (CHF)

Pulmonary: Pneumonia, significant pleural effusions that compromise efficient oxygenation/ventilation of the patient, asthma, chronic obstructive pulmonary disease (COPD) exacerbation

Renal: Chronic renal failure, acute renal failure, hyperkalemia, hypokalemia, acidosis

Heme: Anemia, thrombocytopenia, coagulation disorders

Neurologic: Metastatic disease, recent transient ischemic attack (TIA) or cerebrovascular accident (CVA), new-onset paresthesia or motor deficit

Delaying surgery may be indicated if:

Any of the above conditions are not properly worked up or treatment needs to be optimized.

3. What are the implications of co-existing disease on perioperative care?

N/A

b. Cardiovascular system

Acute/unstable conditions: An effort must be made to make sure the patient is hemodynamically stable before going to the operating room (OR). A full cardiovascular evaluation is in order. Assessment of baseline functional status, electrocardiogram (EKG), echocardiogram as well as any further work-up (i.e., stress test, cardiac catheterization) and therapy (angioplasty, stent, coronary artery bypass surgery [CABG]) that may be indicated to medically optimize the patient prior to starting the procedure.

Baseline coronary artery disease or cardiac dysfunction - goals of management: The goal of management is to closely monitor hemodynamic status throughout the surgery and the perioperative period to minimize the risk of the patient developing an acute complication of baseline cardiovascular pathology, if there is any.

c. Pulmonary

Chronic obstructive pulmonary disease (COPD)

Assessment of preoperative respiratory status should be obtained, if indicated, by preoperative clinical evaluation, pulmonary function tests (PFT’s) as well as compliance and effectiveness of recommended therapy. Bronchodilator therapy may be needed, and chronic use of steroids in severe cases, which would warrant administration of steroid stress doses perioperatively.

Obstructive sleep apnea (OSA)

Preoperatively it is important to know if the patient has been formally diagnosed with OSA, and if so, if he/she is compliant with any of the possible therapies and how much relief of some of the symptoms in response to the prescribed therapy. If no formal diagnosis has been made, clinical evaluation of the sleep pattern, snoring, and daytime somnolence are useful when evaluating the possibility of having difficulty ventilating the patient on induction of general anesthesia. Sleep apnea together with other predictors of difficult intubation are an indication for a possible awake fiberoptic intubation or use of other airway adjuvants. Echocardiographic evaluation for pulmonary hypertension is indicated in severe cases.

Reactive airway disease (asthma)

Medical optimization of any reactive airway must precede induction of general anesthesia. If steroids are part of this regimen, a stress dose must be administered in the perioperative period.

d. Renal-GI:

Evaluation of baseline renal function as well as any electrolyte or acid-base disturbance must be performed and corrected if possible.

If medical management is not effective or feasible, and the degree of such disturbances warrants it, hemodialysis must be considered.

e. Neurologic:

Perioperative concerns specific to this kind of procedure include maintenance of nerve function postoperatively (in the case of limb-salvage procedures) and the development of phantom limb pain (for hemipelvectomy). To help reduce either one from happening, proper surgical dissection is essential, but, for the latter even when this is provided, minimization of the length of preoperative limb pain and a multidisciplinary approach may improve outcomes. Development of phantom limb pain seems to be multifactorial. The use of epidural analgesia to prevent phantom limb pain is controversial.

Acute issues: Phantom limb pain (hemipelvectomy) and preservation of nerve function (limb-salvage procedures) are specific for this kind of surgery.

Chronic disease: Maintenance of therapy perioperatively on patients with Parkinson disease, as well as avoiding precipitating factors (i.e., dopamine antagonists) helps diminish exacerbations of symptoms during the perioperative period. In patients at risk for cerebrovascular events avoiding insults that may precipitate acute deterioration (such as hypotension, hypovolemia, and hypertension, to name a few) will hopefully minimize the incidence of complications.

f. Endocrine:

Diabetes: Optimal glycemic control in the perioperative period is known to decrease the incidence of diabetes complications (diabetic ketoacidosis, hyperosmolar coma), as well as complications of surgical relevance such as infections. In brittle diabetics, intraoperative blood glucose monitoring needs to be performed more frequently. In some instances, an insulin drip may be indicated.

Hypo/hyperthyroidism: Patients should be functionally euthyroid. Medical management of baseline pathology should be continued until the day of surgery. For acute exacerbations, an endocrinologist’s input is important.

Hematologic: Baseline CBC, coagulation profile and type and screen are in order prior to surgery to optimize patients for what could be potentially massive blood loss. Understanding and correcting baseline derangements, whether by medical management or transfusion therapy, are important. Availability of blood products should be arranged ahead of time with the blood bank and continuous communication with that department is essential for a good outcome in the perioperative period.

4. What are the patient’s medications and how should they be managed in the perioperative period?

Discontinue any over-the-counter drugs that may interfere with coagulation, normal platelet function, or cause any electrolyte disturbances, 1-2 weeks prior to surgery; this includes herbal medications.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Chemotherapeutic agents can have side effects influencing perioperative outcome. Specific to this patient population is a concern over Adriamycin cardiotoxicity and bleomycin pulmonary toxicity.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Continue antihypertensive medications, with the exception of diuretics, which should not be taken on the morning of surgery. Antiarrhythmics should be continued up until the day of surgery.

Pulmonary: Continue COPD and asthma medications up until the morning of surgery. Interruption of optimal medical management in any of the two circumstances may increase the risk of the patient developing an acute exacerbation of the symptoms in the perioperative period. Patients with obstructive sleep apnea (OSA) are encouraged to bring their continuous positive airway pressure (CPAP) machine in to the hospital, to be used postoperatively.

Neurologic: Maintenance of therapy perioperatively on patients with Parkinson disease, as well as avoidance of precipitating factors (i.e., dopamine antagonists) aims to dodge exacerbations of the symptoms during that period. On patients at risk for cerebrovascular events, avoiding insults that may precipitate acute deterioration (such as hypotension, hypovolemia, and hypertension, to name a few) will minimize the incidence of this situation.

Antiplatelet: The surgeon should advise if antiplatelet therapy should be discontinued preoperatively. If so, medications need to be discontinued at an appropriate time to avoid antiplatelet activity, for example clopidogrel (5-7 days) and ticlodipine (14 days). If the indication for such therapy is the presence of cardiac stents, careful analysis of the risks/benefits must be evaluated if no alternative treatment is being administered (i.e., discontinuing clopidogrel without continuing aspirin). There is concern about acute thrombosis of stents if all antiplatelet medications are discontinued. Since this particular topic has been the subject of much controversy lately, the recommendation is to check on the most recent guidelines.

Psychiatric: Continue antipsychiatric regimen and restart as soon as possible in the perioperative period.

j. How to modify care for patients with known allergies?

It goes without saying to avoid any drug to which the patient has a known allergy, and any other drugs that belongs to the same family of drugs that may elicit an allergic reaction. In the specific case of antibiotic allergies, appropriate alternative medications must be chosen.

k. Latex allergy-

If the patient has a sensitivity to latex (e.g., rash from gloves, underwear, etc.) one wants to avoid an anaphylactic reaction, so prepare the operating room with latex-free products.

Progressively, hospitals around the country are moving towards a latex free environment to avoid this kind of exposure in the perioperative period. If the facility you work in does not take this precaution, the availability of a latex-free cart is advised to have everything that may be needed to effectively avoid this allergen in this setting.

l. Does the patient have any antibiotic allergies?

If so, choose appropriate medications.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia (MH)

Documented: Avoid all triggering agents such as succinylcholine and inhalational agents:

  1. Proposed general anesthetic plan: total intravenous anesthesia (propofol, etomidate, ketamine, narcotics, nondepolarizing muscle relaxants, dexmedetomidine may all be used safely, as well as nitrous oxide.

  2. Ensure MH cart available: fully stocked with dantrolene or other newer MH treatment medication. MH Hotline [MH protocol]

  3. Family history or risk factors for MH: If any family history is present, take precautions as patient is at high risk. Previous uneventful exposure to anesthetics may be possible on patients who may later develop it. Always be vigilant.

Local anesthetics/muscle relaxants

Local anesthetics used in epidural solutions and nondepolarizing muscle relaxants are safe to use.

5. What laboratory tests should be obtained and has everything been reviewed?

CBC, basic metabolic profile (BMP), coagulation profile, LFTs, thyroid function tests (TFT)s, chest X-ray (CXR), EKG, echocardiogram if needed.

Hemoglobin levels: Hematocrit (hct) levels coming into the OR should be at a level that provides adequate oxygen delivery to end organ systems and should be maintained at those levels throughout the surgery and the perioperative period.

Electrolytes: Review to make sure there is no electrolyte disturbance or renal failure, whether acute or chronic. Correlate if necessary with previous exams done at an earlier date.

Coagulation panel: Check for appropriate coagulation profile.

Imaging: CXR, echocardiogram, stress test and cardiac catheterization results if indicated

Other tests: TFTs.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

General anesthesia or combined general with the use of an epidural for neuraxial block may be used for this procedure. The use of a combined epidural and general anesthesia provides for pain relief but raises concern of an epidural in place in a patient undergoing a procedure potentially associated with significant blood loss and coagulopathy. The coagulation profile has to be monitored closely for proper management and timing of epidural catheter removal.

Since the patient is placed in the lateral decubitus position intraoperatively, it is preferable to employ a general anesthetic after implementation of the regional technique and avoid dealing with intubating a potentially hypotensive, bleeding patient in the lateral decubitus position who may also have a difficult airway. In limb-salvage procedures, regional techniques such as femoral and sciatic catheters may be used to supplement a general anesthetic. Coagulation issues still apply.

Monitoring

  • Standard ASA monitors, including temperature monitoring are to be followed.

  • Large-bore IV access with at least two IV catheters.

  • A central venous triple lumen catheter for fluid resuscitation and pressure monitoring may be inserted after induction of GA or with sedation if regional anesthesia will be used exclusively. In patients with known cardiac disease, a pulmonary artery catheter may prove helpful for intraoperative management.

  • An arterial line is placed to help maintain hemodynamic control as well as for ABGs, Hgb/Hct, coagulation profile, and platelet count.

  • Coordinate with the blood bank to ensure immediate availability of blood products and blood components (PRBCs, FFP, PLTs) as needed to correct anemia, thrombocytopenia, or any coagulopathy that may develop.

  • Cell Saver is not used if the procedure is performed for cancer or infection, while it may be used for chronic vascular or arterial occlusions.

  • Monitor blood loss carefully, initially utilizing crystalloids and colloids, until hemodynamics or lab values indicate that PRBCs should be administered. Monitor urine output, observe for lowered CVP, tachycardia, and/or hypotension as indicators that blood products are indicated. Administer blood products as needed (using PRBCs initially) and closely follow Hgb and Hct levels as well as CVP, so as to keep those values as reasonable as possible. After significant blood loss occurs, coagulopathy can become an issue so replace platelets and FFP in appropriate ratios (see below).

  • Damage control resuscitation (DCR) and the use of massive transfusion protocols are methods that can be used to approach and treat both massive hemorrhage and trauma situations. Massive transfusion protocols are used by many institutions and they involve blood banks preparing multiple units of red blood cells, plasma, and platelets in a 1:1:1 ratio. Damage control resuscitation involves control of surgical bleeding; early use of the massive transfusion protocol if needed; limiting the use of crystalloid intravenous fluids; preventing and treating hypothermia, hypocalcemia, and acidosis; and hypotensive resuscitation methods.

  • After conclusion of surgery, the decision to extubate the patient should be made carefully and should be based on factors such as the patient’s comorbidities, degree of intraoperative fluid shifts, blood loss, urine output, hemodynamic stability, temperature, consideration as to whether significant postoperative bleeding is a concern, and the ability of the patient to meet basic extubation criteria.

Regional anesthesia

Epidural analgesia is very beneficial in treating acute perioperative pain. Lumbar plexus, femoral, sciatic blocks may be used, based on the extent of surgery. However, bleeding and coagulopathy are concerns when using any type of catheters in patients who are at risk for major blood loss. It is in limb-sparing procedures that peripheral catheters may be considered.

Neuraxial

Benefits: Decreases the amount of systemic narcotics used.

Drawbacks: Coagulation profile abnormalities interfere with timing of the discontinuation of an epidural catheter.

Issues: Can worsen hypotension in a hypovolemic patient. If narcotics are used in the epidural infusion, respiratory depression may develop. Epidural hematomas, infections, nerve injury, and suboptimal spread of the local anesthetic solution in the epidural space are also risks.

Peripheral nerve block

Benefits: Decreases amount of systemic narcotics used. May be employed as a single injection or a catheter. Minimizes incidence of postoperative hypotension in comparison to that of local anesthetic epidural infusion.

Drawbacks: Potential for intravascular injection, direct nerve injury. In the presence of coagulopathy, a patient with an indwelling peripheral nerve catheter has a risk of developing a hematoma. It is advisable to make sure sciatic nerve function is present prior to using any local anesthetic in a sciatic nerve catheter.

Issues: Requires expertise in placement for optimal local anesthetic spread.

General anesthesia

Benefits: Airway is secured from the beginning of the procedure. Ability to provide profound analgesia, amnesia, anesthesia, and muscle relaxation during the operation.

Drawbacks: Depending on the length of the procedure and the degree of fluid shifts, it may be necessary to keep the patient intubated in the postoperative period.

Other issues: If the procedure is being performed for cancer, presence of metastatic disease as well as side effects from any chemo/radiotherapy must be considered.

Airway concerns: Airway is secured from the beginning of the procedure. The airway is always of concern when inducing a general anesthetic on a critically ill patient with potentially multiple organ system involvement. An effort must be made to induce anesthesia and secure the airway effectively in a timely fashion eliciting the least amount of hemodynamic instability.

Monitored anesthesia care

This is not an option.

6. What is the author’s preferred method of anesthesia technique and why?

The preferred method of anesthesia would be a combination of general anesthesia together with a continuous epidural catheter.

What prophylactic antibiotics should be administered?

Utilize recommended hospital and national guidelines for determining perioperative antibiotic coverage.

What do I need to know about the surgical technique to optimize my anesthetic care?

Hemipelvectomy is a major surgical procedure. When the surgeon is unable to resect a tumor using a limb-sparing technique or a hip disarticulation, a hemipelvectomy may be required. In this procedure, the lower extremity and much of the bony pelvis are removed. An internal hemipelvectomy may be performed in appropriate candidates. This is a limb-sparing or limb-salvage procedure that involves saving the patient’s limb, while resecting areas involved with the tumor. Hemipelvectomies are named based on the approach and structures involved. The procedures include disarticulating the lower extremity, except for the limb-sparing or internal resection procedure.

What can I do intraoperatively to assist the surgeon and optimize patient care?

  • Avoid hypertension and tachycardia, as it may result in increased bleeding. Maintaining hemodynamic stability while trying to avoid vasoconstrictors (which in turn would compromise adequate oxygen delivery to peripheral tissues) during the case and into the postoperative period will improve outcome by minimizing flap necrosis which is a known complication.

  • Prompt treatment of any coagulopathy that may ensue secondary to significant blood loss despite attempts to avoid it occurring.

  • Maintain normothermia.

What are the most common intraoperative complications and how can they be avoided/treated?

  • Hypovolemia/hypotension and blood loss: Avoided by treating with judicious fluid replacement and vigilance. Replace blood loss as necessary. Do not overcompensate for losses, which carries its own set of problems.

  • Coagulopathy: Amount of blood loss and subsequent transfusion therapy would make this entity likely to appear; in situations of massive blood loss start RBC, platelet, and factor administration as outlined above.

  • Hypothermia: Monitor temperature and institute both forced warm air devices and intravenous fluid warming devices from the beginning of the surgery.

  • Hypocalcemia: As a result of repeated PRC transfusion, replace depletion of calcium if needed.

Complications

Cardiac: Acute coronary syndrome, hypovolemic shock, new-onset arrhythmias, CHF.

Pulmonary: Fluid overload, pleural effusions, atelectasis, bronchospasm, aspiration, airway edema, inadvertent extubation, inability to reintubate.

Neurologic: Cerebrovascular insufficiency as a result of hypovolemia/hypotension, phantom limb pain, new-onset motor deficits.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

The patient must meet basic extubating criteria, namely, adequate tidal volumes and respiratory rate, sustained head lift, leak around endotracheal tube, adequate oxygenation/ventilation, and absence of wheezing. Review fluid status and physiologic parameters to make sure the patient is stable.

c. Postoperative management

  • Patients may exhibit significant postoperative bleeding into drains so serial Hct levels should be obtained.

  • Fluid status should be continually evaluated by observing CVP, urine output, and blood pressure. Third spacing or blood loss into the wound can result in significant intravascular hypovolemia, hypotension, and shock.

  • Pain control may be achieved with the use of epidural infusion with local anesthetics and narcotics after surgery with or without local anesthetics, depending on the current hemodynamic status. Lumbar plexus block or continuous catheter is another option in experienced hands. Catheters may be employed for patients with limb-salvage procedures.

  • In patients in whom regional techniques are not used, IV PCA is a very important consideration. Multimodal medication management is important as well. Overnight monitoring in the ICU of patient’s hemodynamic status, urine output, and analgesia is strongly recommended.

What level bed acuity is appropriate?

  • Patient should be monitored in the ICU. Postoperative intubation may be warranted depending on several factors such as length of procedure, amount of blood loss, amount of fluid replacement, or any baseline cardiovascular or respiratory pathology which would warrant it. Extremely effective pain control may be achieved by the use of epidural narcotics after surgery with or without local anesthetics, depending on the current hemodynamic status. Lumbar plexus block/continuous catheter is another effective means of achieving significant pain control.

  • In patients in whom regional techniques are not employed, intravenous patient-controlled analgesia is an important modality.

  • Overnight monitoring in the ICU of patient’s hemodynamic status, urine output, and analgesia level is strongly recommended. Keep in mind that postoperative bleeding may become an issue in the immediate postoperative period, that if it were to develop it must be addressed expeditiously. Low urine output may be an indicator of bleeding and hypovolemia.

What’s the Evidence?

Asavamongkolkul, A, Pimolsanti, R, Waikakul, S, Kiatsevee, P. "Periacetabular limb salvage for malignant bone tumours". J Orthop Surg. vol. 13. 2005. pp. 2739.

Bernstein, RL, Rosenberg, AD. "Manual of Orthopedic Anesthesia and Related Pain Syndromes". 1993. pp. 414-418.

"Canale and Beaty: Campbell’s Operative Orthopaedics".

Carter, SR, Eastwood, DM, Grimer, RJ, Sneath, RS. "Hindquarter Amputation for Tumors of the Musculoskeletal System". J Bone Joint Surg. vol. 72. 1990. pp. 490-3.

Malawer, MM, Sugarbaker, PH. Musculoskeletal Cancer Surgery. 2004. pp. 405-413.

Miller, TE. "New evidence in trauma resuscitation – is 1:1:1 the answer". Perioperative Medicine. vol. 2. 2013. pp. 13.

O’Connor, MI, Sim, FH. "Salvage of the limb in the treatment of malignant pelvic tumors". Journal of Bone and Joint Surgery. vol. 71.4. 1989. pp. 481-494.

Weinbroum, AA, Marouani, N, Lang, E, Niv, D, Rudick, V. Musculoskeletal Cancer Surgery. 2004. pp. 570.

Yancey, AG, Johnston, GA, Green, JE. "Some surgical principles in hemipelvectomy". J Natl Med Assoc. vol. 42. 1950. pp. 210.

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