Anesthesiology

ORIF of ankle fracture

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What the Anesthesiologist Should Know before the Operative Procedure

The anesthesiologist should know the patient's medical conditions (including additional injuries for patients who have a high-energy mechanism of injury) as well as the surgical plan.

1. What is the urgency of the surgery?

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

Only rarely is there a risk of worse outcome if surgery is delayed several hours. Delaying the surgery for more than a day could affect the surgical plan as swelling and/or fracture blisters could develop which could lead the surgeons to delay surgery.

Emergent: Ankle fractures may require urgent treatment, but very rarely represent true surgical emergencies. Any unstable medical condition (or more life-threatening injury in a multiply injured patient) should be addressed before proceeding with surgical treatment of the ankle fracture as the outcome is not likely to be affected by delaying surgery for several hours if necessary. Open fractures should at least be irrigated thoroughly within 6 hours of presentation, but definitive fixation of the fracture may be delayed.

Urgent: Ankle fractures are often treated surgically within the first 24 hours after injury as significant swelling may not have developed. As swelling becomes more severe, skin closure may become more difficult and fracture blisters may develop over the planned incision site, increasing the risk for wound complications. If surgery is not possible during this time, operative management of the fracture may be delayed for 2 to 3 weeks. Following closed reduction of the fracture, the patient’s ankle can be placed in a splint until definitive treatment is possible. Prior to surgery, the surgeon will often assess the ankle to determine if surgery will be feasible or if the swelling or fracture blisters have still not resolved. For this reason, we prefer to have the surgeon remove the splint and inspect the patient’s ankle before performing a block or inducing general anesthesia. Fractures that are open or are associated with significant soft-tissue injury may be managed in a staged fashion and multiple surgical procedures may be necessary. Irrigation and debridement and possibly external fixation of the fracture may be performed early with definitive internal fixation planned for days to weeks later when the risk of infection may be reduced. For severe soft tissue injuries, complex closure involving vascularized tissue transfer (local or free myocutaneous flaps) or skin grafting may be necessary.

Elective: Although surgery for ankle fractures is never purely elective, it is often scheduled 2 to 3 weeks after the injury for reasons described above. Surgery should not be delayed much past this interval as callus formation may make optimal alignment of fracture fragments difficult. If surgery is delayed too long, the fracture may heal in a bad position, leading to malunion. This could lead to poor function of the ankle and may necessitate more complex reconstructive surgical procedures to restore anatomic alignment.

2. Preoperative evaluation

Patients should have a thorough history and physical examination. Lab or imaging studies should be directed by the history or physical exam findings.

a. Patients presenting with ankle fractures may have unstable medical conditions warranting further evaluation and/or treatment. This usually occurs in patients who have multiple injuries following high-energy trauma or debilitated patients following ground-level falls. For the first group, fixation of the ankle fracture is usually a relatively low priority and more life-threatening injuries (intracranial, thoracic, abdominal) are treated or stabilized first. A thorough evaluation (history, physical exam including primary and secondary trauma surveys, lab tests including CBC, basic chemistry panel, toxiclogy, appropriate imaging including possibly including plain films of the chest, pelvis and cervical spine, FAST scan, CT scans of the head/chest/abdomen and pelvis) should be performed to identify all injuries. This will likely be performed by a team of trauma specialists if the patient is presenting to a trauma center. If this is not the case and the patient’s mechanism of injury makes it likely that serious injuries other than the ankle fracture may be present, consultation with a general surgeon may help guide preoperative evaluation if you are not comfortable with management of trauma patients. If there is significant bleeding from an open ankle fracture (arterial injury), the wound can usually be explored at the bedside to control the source of bleeding. The ankle can then be splinted until the patient is stable enough for more definitive management of the ankle injury. Patients who have fallen from significant heights often have concomitant spine injuries (such as burst fractures of lumbar vertebral bodies) so spinal precautions should be continued until a spinal column injury has been conclusively ruled out, stabilized surgically, or the patient has been placed in an orthotic device.

Debilitated patients may present with ankle fractures for several reasons. First, they may have one or multiple medical conditions that produce osteoporosis (malnutrition, advanced age, chronic corticosteroid use). Second, they may have conditions that impair balance (poor vision, decreased sensation or muscle strength, syncope). The mechanism of injury may provide clues regarding the severity of comorbid disease, but a complete history and physical examination should be performed to identify relevant and potentially unstable medical conditions that may need to be addressed preoperatively. Because surgical fixation of ankle fractures may be delayed for several weeks if necessary, any unstable (arrhythmia, cerebrovascular event, diabetic ketoacidosis) or severe stable medical condition (poorly controlled diabetes, congestive heart failure, seizure disorder) should be addressed preoperatively as this will reduce the risk of perioperative events and improve surgical outcomes. Patients with poorly controlled diabetes, peripheral vascular disease, or who smoke tobacco may be at increased risk for surgical complications due to poor blood flow to the ankle. Tight control of blood glucose in the perioperative period may help prevent wound infection. For patients with severe peripheral vascular disease, further testing may influence surgical planning, as insufficient perfusion of the ankle may prevent healing of the fracture or surgical wounds. Such patients may require a vascular bypass procedure prior to treatment of the ankle fracture, or may not be candidates for surgical treatment of the fracture. Non-operative treatment or amputation may be necessary. Pre-operative smoking cessation may improve perfusion and decrease the risk of fracture non-union or wound complications.

b. Delaying surgery may be indicated the patient has any unstable medical condition. Life-threatening traumatic injuries should be stabilized prior to management of the ankle fracture. Any unstable or chronic severe comorbid disease should be evaluated and the patient’s medical condition optimized prior to proceeding with surgical treatment of the ankle injury. Prior to proceeding with surgery, informed consent should be obtained and the patient’s code status should be clarified. As there are often multiple anesthetic options for patients with ankle fractures, a discussion with the patient and/or designated legal proxy is necessary to determine the safest plan that conforms with the patient’s wishes, as well as what should be done if problems occur.

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

Comorbidities have been shown to increase the risk of complications. Increasing age, complicated diabetes and peripheral vascular disease are all associated with an increased risk.

Perioperative evaluation

Perioperative risk reduction strategies

Operative treatment of ankle fractures is generally considered to be a low-risk surgical procedure. Standard risk-reduction strategies such as perioperative beta-blockade for patients with cardiac risk factors should be employed. Risks of poor surgical outcomes can be reduced by preoperative optimization of chronic medical conditions. Improved blood glucose control in patients with diabetes and smoking cessation can improve the chances of fracture healing and decrease the likelihood of wound infection.A thorough history and physical examination will guide preoperative evaluation. The mechanism of injury may suggest the presence of other injuries or underlying medical conditions.

b. Cardiovascular system

Acute/unstable conditions

Baseline coronary artery disease or cardiac dysfunction - Goals of management

Patients with stable cardiac disease are usually able to safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. General goals of management are minimizing hemodynamic changes (tachycardia, hyper/hypotension) and avoiding agents that may negatively affect cardiac function or interact with the patient’s usual medications. Management of anticoagulation during the perioperative period can be a challenge for patients on warfarin or antiplatelet agents, especially if regional anesthetic techniques are planned. Following recommendations of the ASRA/ESRA guidelines is usually prudent, unless the potential benefits of performing some type of regional block outweigh the potential risks. In this case, a detailed discussion with the patient or proxy so they may give informed consent is essential.

Acute or unstable cardiac conditions should be evaluated and treated prior to surgical management of ankle fractures. If this cannot be done in a timely manner (2-3 weeks) or if the ankle fracture somehow interferes with the treatment plan, surgical stabilization of the fracture can often be done safely under regional anesthesia. In order to minimize hemodynamic changes, peripheral nerve blocks may be superior to neuraxial techniques. It is important to communicate with the surgeon about the plan to ensure the blocks provide coverage for the entire area involved in the procedure (including the tourniquet). Also, ideally there should be some communication between the patient's cardiologist or primary physician, the surgeon and the anesthesiologist to determine whether or not antiplatelet agents (such as clopidogrel) are to be held during the perioperative period. This can prevent delays or other potential scheduling issues. If the patient continues the antiplatelet agents or is given another form of anticoagulation (such as low-molecular weight heparin) as a “bridge” there could be an increased risk of bleeding complications for regional techniques, especially neuraxial. Due to the risk of thrombosis of fresh coronary stents (especially drug-eluting stents) if antiplatelet agents are held, we prefer to do such patient’s surgeries in a hospital-based setting rather than a free-standing ambulatory surgery center. (At our institution we have had patients require emergent angioplasty under similar conditions.)

c. Pulmonary

COPD

Patients with COPD can usually safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. Patients with severe (home oxygen therapy) or worsening lung disease (recent pneumonia) may benefit from regional anesthesia in order to avoid airway instrumentation/mechanical ventilation. Regional anesthesia, especially long-lasting or continuous peripheral nerve blocks may be helpful to avoid respiratory depression from opioid analgesics postoperatively. Continuation of usual medications (bronchodilators) throughout the perioperative period is usually helpful. Smoking cessation can also improve surgical outcomes and should be encouraged.

OSA

Patients with sleep apnea should have the severity of the disease assessed, and appropriate strategies developed to reduce the potential for post-operative exacerbation of their disease by opioid-induced respiratory depression. They should continue the use of their CPAP therapy in the peri-operative period.

Reactive airway disease (Asthma)

Patients with asthma can usually safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. Avoiding general anesthesia may be helpful for patients with severe disease. If airway instrumentation is planned, we will give the patient a nebulized bronchodilator before going to the operating room. A single dose of ketamine on induction or a ketamine infusion may also decrease airway resistance and improve ventilation.

d. Renal-GI:

Patients with kidney disease can usually safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. Patients with severe disease may be more likely to sustain ankle fractures due to osteopenia (secondary hyperparathyroidism). For patients with severe disease (dialysis-dependent), attention must be given to the patient’s volume status and electrolyte levels. It may be helpful to test electrolyte levels immediately prior to surgery. As these patients may have impaired platelet function due to uremia, it may be prudent to avoid neuraxial blocks unless there is no safer alternative. Care must be taken during surgery to protect dialysis access, especially arteriovenous grafts or fistulas as these can become thrombosed during surgery.

Patients with liver disease can usually safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. Patients with severe liver disease may be coagulopathic and as such may not be good candidates for neuraxial techniques. Large amounts of ascites could make positioning for surgery difficult (decreased lung volumes in the supine position). If so, paracentesis may be necessary prior to surgery. Also, low albumin levels could produce ankle edema and increase the risk of wound complications. Medical optimization of liver disease and nutritional status prior to surgery is ideal.

Patients with gastrointestinal disease can usually safely undergo surgical stabilization of ankle fractures under regional or general anesthesia. Patients with gastroesophageal reflux disease (GERD) may not be good candidates for regional anesthesia and sedation due to an increased risk of regurgitation and subsequent pulmonary aspiration. Light sedation may allow the patient to maintain protective airway reflexes. Following NPO guidelines will also reduce risk. Patients with severe GERD or potentially full stomachs should probably have an endotracheal tube placed following rapid-sequence induction unless a pure regional (no sedation) anesthetic is feasible.

e. Neurologic:

Acute issues

Patients with acute neurologic disease may or may not be suitable for surgical managment of ankle fractures based on the type and severity of neurologic symptoms. Life-threatening neurologic conditions such as an acute cerebrovascular event or spinal cord injury should be evaluated and stabilized prior to proceeding with surgery for the ankle injury. Acute peripheral nerve injury could theoretically increase the risk of nerve damage from peripheral nerve block ("double-crush" injury). Regional block may be deferred until a neurologic examination can be performed to rule out nerve injury. It is also possible for a splint, case, or other dressing to compress the peroneal nerve so it may be helpful to rule out peroneal nerve deficits prior to performing a sciatic nerve block to avoid masking the injury or have the injury attributed to the block.

Chronic disease

Patients with chronic neurologic disease are usually able to undergo surgical treatment of ankle fractures, but the anesthetic plan must be tailored to the patient’s condition. Patients who have no or minimal sensation in the injured ankle (such as after a stroke or spinal cord injury) may not require much anesthetic, but autonomic hyperreflexia may result from surgical stimulation or tourniquet pain. Succinylcholine should obviously be avoided in patients with denervating injuries due to the risk of hyperkalemia, and these patients may be relatively resistant to nondepolarizing muscle relaxants. Patients who have dementia may benefit from a regional anesthetic to minimize the risk of potential delirium following a general anesthetic or from opioid analgesics postoperatively. Patients with demyelinating conditions such as multiple sclerosis could potentially have higher risks of neurologic injury following a neuraxial or peripheral nerve block, but the relationship between regional anesthesia, surgical trauma and the underlying condition remains unclear. There are case reports of patients with Guillain-Barre syndrome experiencing a relapse weeks after receiving epidural anesthesia, though the potential for similar exacerbation following peripheral nerve blocks is not well known. These patients may still be candidates for regional anesthesia, especially if they are at increased risk of complications from general anesthesia, but a detailed discussion of the risks and benefits should take place so that the patient or proxy may give informed consent

f. Endocrine:

The most common endocrine condition in patients presenting for surgical treatment of ankle fractures is diabetes mellitus. Patients with diabetes may be at increased risk for ankle fractures due to an increased risk of falls due to peripheral neuropathy and decreased vision. Patients with diabetes may be at an increased risk for wound infection or non-union due to decreased perfusion to the ankle. Tight glucose control in the perioperative period may decrease these risks. Patients receiving general anesthesia should have frequent monitoring of blood glucose levels during surgery to prevent hyper- or hypoglycemia. These patients could potentially be at increased risk of nerve injury following a peripheral nerve block (“double-crush” injury) though this remains controversial. Use of a peripheral nerve stimulator to perform a block in diabetic patients may be difficult due to underlying neuropathy. Use of ultrasound or high stimulating currents and long pulse-width settings on the nerve stimulator may facilitate block placement.

Chronic corticosteroid use could increase the risk of wound infection or nonunion. A “stress-dose” could be considered if patients exhibit signs of adrenal insufficiency. Other stable common endocrine conditions (such as hypothyroidism) usually do not significantly affect surgical or anesthetic management of patients with ankle fractures. Patients with severe conditions (such as thyroid storm or myxedema coma) need to be medically stabilized prior to proceeding with surgery.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan

Patients with multiple injuries may undergo multiple simultaneous or sequential surgical procedures. This should be clarified prior to developing an anesthetic plan. If the ankle fracture is amenable to a minimally invasive surgical repair and the patient has more severe injuries elsewhere, a block for the ankle fracture may increase perception of pain from the other injuries and not improve the patient’s overall pain control. In addition, mobilization of the patient must be considered. Usually, patients are to be non-weight-bearing on the injured ankle so blocks do not significantly affect mobilization.

High-energy injuries or specific fracture patterns (more proximal tibial injuries) may increase the risk of compartment syndrome of the leg or foot. Also patients who are multiply injured, hemodynamically unstable and who require aggressive fluid and/or blood product resuscitation may be at increased risk for compartment syndrome. Such patients may not be good candidates for regional blocks as the block could mask symptoms of the compartment syndrome and delay diagnosis leading to worse outcomes. A discussion with the surgeons regarding the risk for compartment syndrome may be helpful in such situations.

The incidence of chronic pain following ankle fractures is significant, and a strategy to reduce the patient’s risk of developing a chronic pain syndrome is certainly warranted. Improving acute pain control with peripheral nerve blocks and/or a multimodal analgesic regimen may be helpful.

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

Most prescription, over-the-counter, and herbal medications can be continued through the perioperative period. Patients may be advised by their surgeon to avoid nonsteroidal analgesics as these could increase the risk of nonunion.

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

Because patients presenting for surgical treatment of ankle fractures are often seen days to weeks following the injury, they are often taking opioid pain medications prior to surgery. This may lead to tolerance and increase requirements postoperatively. Though this could also increase the risk of respiratory depression from opioids administered by the anesthesia team, we usually recommend that patients take pain medication with a small sip of water on the day of surgery if needed.

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

  • Many antihypertensives should be held on the morning of surgery as they can increase the risk of hypotension in the setting of general or neuraxial anesthesia and make hypotension more difficult to treat with standard pressor agents. These include ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, and diuretics. Beta-blockers and clonidine should be continued to prevent rebound hyopertension. In general, antiarrhythmics should be continued.

  • Pulmonary medications should be continued. We usually ask that if patients use a rescue inhaler, they bring it on the day of surgery and use it immediately prior to surgery.

  • Renal medications should be continued during the perioperative period.

  • Neurologic medications should be continued during the perioperative period.

  • See section above on cardiovascular disease.

  • Psychiatric medications should be continued during the perioperative period.

  • Immunomodulating medications (for autoimmune or rheumatologic conditions or for patients with previous solid-organ or bone marrow transplants) should be continued in the perioperative period.

j. How To modify care for patients with known allergies -

Avoid medications to which the patient is allergic.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

For patients with allergy to adhesives, avoid known sensitizing adhesives (such as mastisol) for surgical dressings and/or if a continuous block is planned.

l. Does the patient have any antibiotic allergies-

Patients with closed fractures are usually given a prophylactic dose of a first-generation cephalosporin to cover common skin flora. Patients with known severe reactions to beta-lactam or cephalosporin antibiotics may be given an alternative agent (such as clindamycin). High-grade open injuries are an indication for the addition of an aminoglycoside, so patients with known sensitivity to this class of antibiotic, hearing loss or, renal insufficiency may benefit from a different class of antibiotic to improve gram-negative coverage.

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

Malignant hypertherthemia (MH)

Documented

Regional anesthesia with or without intravenous sedation is an excellent strategy for avoiding triggering agents. The areas of the ankle involved, type of tourniquet, and duration of the surgical procedure should be determined to plan an appropriate regional anesthetic. If regional anesthesia is not possible, a nontriggering general anesthetic (avoiding succinylcholine or inhalational anesthetics) is also appropriate.

Family history or risk factors for MH

Again, regional anesthesia/sedation would be the technique of choice to avoid potential triggers of MH.

True allergies to local anesthetics are rare, especially if preservative-free formulations are used. If a patient has a known immune-mediated reaction to a local anesthetic, anesthetics from another class (amides vs. esters) should be safe.

Muscle relaxants do not necessarily have to be used for ankle fracture surgery. Surgeons are usually able to achieve adequate reduction without neuromuscular blockade. A dense peripheral nerve block (surgical block) or spinal anesthetic can also produce profound muscle relaxation if the surgeons require, but this should obviously be discussed prior to starting surgery.

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

Laboratory tests, imaging studies (other than of the ankle) or other tests should be based on the findings of a comprehensive history and physical examination. There are no studies necessary specifically for the surgical procedure. Because the surgeons will usually use a tourniquet, blood loss and fluid shifts are typically minimal.

  • Baseline blood counts may be helpful for patients with known anemia or other suspected hematologic condition (such as thrombocytopenia). If there is an open fracture with a large amount of bleeding, a baseline hemoglobin level may be helpful.

  • Unless dictated by the patient’s history, electrolyte studies are unnecessary for the majority of patients scheduled for ankle fracture surgery.

  • Coagulation studies are not needed unless the patient has a history of abnormal clotting or clinical signs of coagulopathy.

  • Chest radiographs, electrocardiograms, echocardiograms, or other imaging studies are not specifically indicated for ankle fracture surgery.

  • Other tests are not indicated unless the patient has a known or suspected medical condition or associated injury that requires further workup in order to develop a workable anesthetic plan.

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

Many types of anesthetic techniques (as well as combinations of techniques) are suitable to provide adequate surgical anesthesia for ankle fracture surgery. Determining which technique will be best for a particular patient requires knowledge of the patient’s medical history, the surgical plan, the type of facility the procedure is to be performed and the anticipated disposition of the patient. Many patients prefer to “just be knocked out” so general anesthesia is an acceptable option for surgical anesthesia unless otherwise contraindicated. Some patients are not good candidates for general anesthesia or are afraid of “being put under”; regional techniques (such as a spinal block) are equally appropriate.

These surgeries are often associated with significant postoperative pain, so a regional block for postoperative pain control is a good option unless contraindicated. Some patients may “hate needles” and so not want a block before surgery. It is often useful to discuss the option of a block with the patient before surgery so that they can request one postoperatively if they experience significant pain after surgery. Patients who have blocks done before surgery often have lower requirements for inhalational anesthetics and opioid analgesics. As a result, this may decrease the risk of side effects such as nausea, speed recovery and improve satisfaction. In addition, the blocks may easier to perform preoperatively as patients may be more difficult to position prone after surgery (may be easier to perform sciatic blocks in prone position, especially catheters although these blocks can be performed using a lateral approach) and may experience more pain during block placement postoperatively if a nerve stimulator is used to perform the block. However, patients who have blocks after surgery may appreciate the blocks more as they may experience significant pain initially and notice the reduction in pain once a block has been done. Also, the block has a longer effective duration when it is performed later. We usually offer a block (usually popliteal sciatic with or without a saphenous block) and discuss the pros and cons of timing the block before vs. after surgery.

a. Regional anesthesia

1. Neuraxial

  • Neuraxial blocks can be used to provide surgical anesthesia of postoperative analgesia for ankle fracture surgery. Neuraxial blocks are usually simple to perform for the majority of anesthesia providers, and do not require much special equipment or training. Spinal anesthesia provides good coverage of the entire surgical area, including the thigh if a thigh tourniquet is planned, and consistently provides good operative conditions with a rapid onset. Epidural blocks can be added in combination (combined spinal-epidural) if a very long surgical time is anticipated and the patient is not a good candidate for general anesthesia and peripheral blocks are not feasible.

  • Spinal anesthesia does not provide prolonged postoperative pain relief as single-injection techniques are most commonly performed. Continuous spinal techniques can be difficult to manage postoperatively as it may be difficult to provide optimal pain relief without producing a high spinal block. Epidural blocks by themselves are not ideally suited for ankle fracture surgery as there may be relative sparing of sacral dermatomes. This may require large volumes of anesthetic to cover the ankle and lead to significant side effects, such as hypotension. In addition, neuraxial blocks usually affect both legs, making mobilization difficult if the blocks are used for postoperative analgesia especially if the patients are to be discharged home after surgery. Long-acting intrathecal opioids (such as duramorph) could be used to provide postoperative analgesia but may be associated with significant side effects such as nausea or pruritus. Also because of the possibility of delayed-onset respiratory depression, long-acting intrathecal opioids are not a good option for outpatient surgery. Because of the risk of epidural hematoma, neuraxial blocks are not ideal in patients receiving anticoagulant medications or with underlying clotting disorders.

2. Peripheral nerve block

  • Peripheral nerve blocks can be used to provide surgical anesthesia or postoperative analgesia for ankle fracture surgery. Unlike neuraxial techniques, peripheral blocks have minimal associated side effects (such as hypotension, pruritus, nausea, urinary retention or respiratory depression). Patients can be safely discharged home with an indwelling perineural catheter (providing adequate mechanisms for follow-up are in place), allowing patients to undergo extensive surgery on an outpatient basis. In addition, because the blocks used to cover the ankle and/or thigh are fairly superficial, bleeding can usually be controlled by applying pressure. In addition the complications of bleeding, while potentially significant, are not as great as for neuraxial techniques. This may allow peripheral blocks to be performed in patients with underlying clotting disorders or on anticoagulants if the benefits of performing the block outweigh the potential risks of bleeding at the block site(s).

  • Peripheral nerve blocks may not be familiar to anesthesia providers who do not routinely perform the blocks, so procedure times may be longer and success rates may be lower than for neuraxial techniques. In addition, special equipment such as block needles or catheter kits, nerve stimulators, or ultrasound machines may be required to perform peripheral blocks. Multiple blocks may be necessary if they are to be used for surgical anesthesia, especially if a thigh tourniquet is planned. In addition, more proximal blocks are necessary if the surgeons prefer to use a thigh tourniquet. More proximal sciatic blocks may be more technically challenging, especially if the patient is obese or cannot be positioned well to facilitate block placement (lateral or prone positions) if they have multiple injuries or other preexisting conditions that limit mobility. Because sciatic blocks can require a long onset time for surgical anesthesia, especially if a long-acting local anesthetic is used, peripheral blocks may be better for postoperative analgesia and combined with general or spinal anesthesia for surgical anesthesia. In addition, because large doses of local anesthetics are often used (especially with nerve stimulation techniques and/or multiple blocks) there may be an increased risk of local anesthetic systemic toxicity (LAST). Patients should be monitored closely for signs/symptoms of LAST and lipid emulsion should be available should LAST be suspected. Both neuraxial and peripheral blocks can mask signs/symptoms of compartment syndrome, and should probably be avoided if the patient is at significant risk of developing a compartment syndrome of the leg or foot.

b. General Anesthesia

  • General anesthesia is adequate to provide surgical anesthesia for ankle fracture surgery. It is simple to perform in the majority of patients, covers the entire surgical area (including thigh), and can be used for either short or long-duration procedures. Patients often prefer to be unaware of what is going on in the operating room, and are concerned about hearing drills/saws, etc. being used on them during surgery. Unlike neuraxial techniques, patients do not need to wait for a motor block to resolve before discharge from the PACU, and so general anesthesia may be preferable for short procedures or facilities where prolonged stays in the PACU are problematic (such as ambulatory surgery centers).

  • Many patients may not be good candidates for general anesthesia due to preexisting medical conditions (such as malignant hyperthermia) or previous bad experiences with general anesthesia (such as prolonged emergence or nausea/vomiting).

  • General anesthesia does not provide postoperative analgesia, and once the effect of the anesthetic agents start to resolve, the patient may experience significant pain. This may be difficult to control with oral medications alone, leading to unplanned admission for pain control. Even intravenous medications may not provide optimal pain control and may have significant adverse effects, and several studies have shown peripheral blocks to provide superior early recovery.

  • Patients with known or suspected difficult airway management may not be good candidates for general anesthesia. However, any time a regional anesthetic is planned, the anesthesia provider(s) must be prepared to convert to a general anesthetic if the regional technique does not provide adequate surgical anesthesia (incomplete block or disinhibition from sedative medications used in conjunction with regional block) of if the patient cannot adequately support his/her ventilation/oxygenation (over-sedation or anaphylactic reaction). Because it may be easier to secure the airway in a controlled fashion rather than urgent/emergently, it may be safer to prophylactically establish a definitive airway if it seems likely that problems with airway management will arise during surgery.

c. Monitored Anesthesia Care

  • For very minor surgeries (such as removal of small amounts of superficial retained hardware) local anesthesia and monitored anesthesia care may provide adequate surgical conditions. This type of anesthetic may decrease the risk of side effects of anesthesia (such as delayed emergence or nausea/vomiting) and may allow patients to bypass the first phase of recovery. Monitored anesthesia care combined with some form of regional anesthesia can be an excellent option for ankle fracture surgery.

  • Because manipulation of bone fragments can be very painful, monitored anesthesia care is often not adequate by itself to provide surgical anesthesia for ankle fracture surgery.

  • Just as for regional anesthesia, anesthesia providers must be prepared to convert to general anesthesia should unanticipated problems arise during monitored anesthesia care.

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

At our institution, we most commonly place a sciatic perineural catheter preoperatively using the posterior popliteal approach. We perform the block with the patient in the prone position and use ultrasound guidance with or without nerve stimulation to perform the block. If the patient is having extensive work on the medial ankle, we will add a saphenous nerve block. We typically perform this block using ultrasound guidance with the patient prone. If the majority of the surgical procedure involves the medial ankle we will place a catheter along the saphenous nerve as well. We perform the blocks in a specialized block area, and then take the patient to the operating room for surgery. We typically use general anesthesia to provide surgical anesthesia unless there is some specific contraindication. We then typically discharge the patient home with the sciatic (and possibly saphenous) catheter(s) in place after attaching it (them) to a portable, disposable device to infuse local anesthetic along the nerve(s) for up to three days after surgery. We call the patient on the first postoperative day to answer any questions that may arise regarding the block(s). We have someone on call 24/7 to address urgent/emergent issues potentially related to the block(s). The patients or their caregivers then remove the catheters at home and discard the catheter(s) and pump(s). If patients are not a good candidate to be sent home with a continuous infusion of local anesthetic (such as patients living in an unstable home situation), we often perform single-injection blocks. For these patients, we often perform the block(s) postoperatively to extend the effective duration of the block(s). We usually perform these blocks in the PACU and may perform them with the patient supine or prone.

What prophylactic antibiotics should be administered?

Patients with closed fractures or type I or II open fractures should receive an antibiotic directed against gram-positive organisms. This is typically a beta-lactam though vancomycin or clindamycin can be used for patients who are allergic to penicillin. Patients with type III open fractures should also be given antibiotics directed against gram-negative organisms. This is typically an aminoglycoside. Fluoroquinolones may impair fracture healing and may increase the risk of wound infection compared to aminoglycosides. Patients at risk for renal failure (such as elderly patients) may benefit from a fluoroquinolone, however as the risk of aminoglycoside-related renal failure may outweigh the risk of wound infection. Patients with heavily contaminated wounds that may be contaminated with clostridium (such as farm-related injuries) should be given high-doses of penicillin unless they are allergic. Patients' immunization status with regards to tetanus should be reviewed, and patients who have not been recently immunized may require a booster and unimmunized patients may require immunoglobulin prophylaxis.

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

It is helpful to know the patient’s fracture pattern as well as the surgical plan to provide optimal care, especially if a peripheral nerve block is planned. If the fracture primarily involves the medial malleolus, a block of the saphenous nerve in addition to a sciatic nerve block may help to provide adequate surgical anesthesia or postoperative analgesia. If there is no or minimal involvement of the medial ankle, a sciatic block alone may be sufficient, especially if the surgeon can infiltrate the skin incision on the medial ankle with local anesthetic. If the surgeon is able to use a calf tourniquet, the popliteal approach to the sciatic nerve may be adequate to provide surgical anesthesia, especially if combined with a saphenous nerve block. If the surgeon has to use a thigh tourniquet, the popliteal block can provide postoperative analgesia, but general or spinal anesthesia is necessary to provide adequate surgical anesthesia. If a neuraxial block is not possible but avoidance of general anesthesia is indicated, a more proximal sciatic block combined with a femoral nerve block can allow the patient to tolerate a thigh tourniquet during surgery. If this is the case, using a long-acting local anesthetic (bupivacaine, ropivacaine) for the sciatic block may provide prolonged postoperative pain relief, while an intermediate-acting local anesthetic (lidocaine, mepivacaine) for the femoral block is adequate to prevent tourniquet pain during the surgery. If a long-acting local anesthetic is used for the sciatic block, it is important that the block be performed well before the surgery (at least 30 minutes) to allow the block to set up. It is also possible to place a catheter by the sciatic nerve, dose it initially with a faster-acting anesthetic, and use a longer-acting anesthetic later to provide postoperative pain control.

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

The anesthetic plan needs to take into account the likely duration of surgery and the entire area (including tourniquet) involved in the procedure. Blood loss is usually minimal as a tourniquet is typically used, so hypotension or cell saver are unnecessary. Tourniquet pain can be minimized by padding the tourniquet site well and using the lowest possible inflation pressure. If the patient is exhibiting signs of tourniquet pain under general anesthesia (increase in blood pressure and/or heart rate usually about an hour after inflation) avoiding long-acting agents (such as opioids or beta-blockers) may be prudent as their effects may persist after deflation of the tourniquet and make management more difficult (prolonged emergence or hypotension).

Complications

Cardiac complications are rare as a result of the surgical procedure itself, but pain associated with the procedure (including tourniquet pain) may lead to hypertension and tachycardia that could increase the risk of myocardial ischemia/infarction. Preserving hemodynamic stability by anticipating by adjusting depth of anesthesia during more or less stimulating portions of the surgical procedure or by using an appropriate regional technique may prevent perioperative cardiac events.

Pulmonary complications from ankle fracture surgery are rare, but may be associated with airway instrumentation/general anesthesia or respiratory depression from opioid pain medications. Patients at risk for pulmonary complications may have the risk reduced by having surgery under regional anesthesia. In addition, regional techniques to provide long-lasting pain control may decrease the risk of respiratory depression from opioid medications in patients susceptible to their sedating effects (such as patients with obstructive sleep apnea).

Central nervous system complications are rare following ankle fracture surgery. Injury to peripheral nerves is relatively common, however. Peripheral nerve injury is usually multifactorial and several issues associated with ankle fracture surgery can contribute to an increased risk for nerve injury. The patient may have preexisting conditions (such as diabetic neuropathy), a nerve can have a partial or complete injury associated with the ankle injury, the tourniquet can decrease blood flow to the nerves and peripheral blocks can injure nerves mechanically (needle trauma) or as a result of local anesthetic neurotoxicity. It is important to discuss the risks of nerve injury with the patient before surgery, and to adopt a “team” approach to managing perioperative nerve injuries. Because injuries can result even if a block is not performed, it is important for surgeons and anesthesia providers to not immediately assume a nerve block is the only cause of a nerve injury. Chronic pain is not uncommon after ankle fractures. Use of multimodal analgesic regimens may decrease the patient’s risk of developing a chronic pain syndrome (“protective analgesia”) and improving acute pain control (possibly involving the use of regional blocks) may also decrease the risk.

a. Neurologic:

N/A

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

No.

c. Postoperative management

What analgesic modalities can I implement?

Regional block techniques (especially peripheral nerve blocks) provide excellent postoperative analgesia. As these procedures can be extremely painful, continuous techniques may be optimal. Multimodal analgesic regimens can also be beneficial to improve pain control and decrease side effects from high doses of opioid analgesics. Surgeons may want patients to avoid using NSAIDs to promote fracture healing, so use of NSAID’s as part of a multimodal regimen should be discussed with the surgeon.

What level bed acuity is appropriate?

The level of bed acuity largely depends on the patient’s preexisting medical conditions. Ankle fracture surgery can often be performed on an outpatient basis if the patient is medically suitable for outpatient surgery, especially if a regional block can be done to provide prolonged postoperative pain relief. If a regional block cannot be performed, there is a significant risk of unplanned admission for pain control.

What are common postoperative complications, and ways to prevent and treat them?

Common postoperative complications are often the result of pain or treatment of pain. Pain-related hypertension and tachycardia can increase the risk of perioperative cardiac events, and opioid related side effects can cause complications ranging from nausea to apnea and hypoxic brain injury. Regional techniques may prevent these complications and are often beneficial for patients undergoing ankle fracture surgery. DVT/PE can occur, though is not common enough to warrant routine prophylaxis such as aspirin or subcutaneous low-molecular weight heparin. Regional blocks may produce vasodilation and promote venous flow thus decreasing the risk of DVT/PE, though use of a tourniquet negates much of this benefit. Wound infection and non-union of the fracture are not uncommon. Tight glucose control, supplemental oxygen and regional blocks may improve perfusion of the ankle and decrease the risk, though the use of a tourniquet again negates much of the benefit of these strategies. Patients may be at increased risk for falls following ankle surgery. This can be due to underlying medical conditions, opioid pain medications, or decreased sensation/motor strength from a nerve block. Patients should follow weight-bearing restrictions specified by the surgeon (usually non-weight bearing) and have crutch training prior to discharge to home.

What's the Evidence?

Sites, BD, Gallagher, J, Sparks, M. "Ultrasound-guided popliteal block demonstrates an atypical motor response to nerve stimulation in 2 patients with diabetes mellitus". Reg Anesth Pain Med. vol. 28. 2003 Sep-Oct. pp. 479-82.

(This paper describes a lack of appropriate motor response despite the use of a high stimulating current in two patients with diabetes. Blocks were performed uneventfully under ultrasound guidance. This paper suggests that nerve stimulation may be difficult in patients with diabetes, and that ultrasound may be helpful in patients with preexisting neuropathy.)

White, PF, Issioui, T, Skrivanek, GD, Early, JS, Wakefield, C. "The use of a continuous popliteal sciatic nerve block after surgery involving the foot and ankle: does it improve the quality of recovery". Anesth Analg. vol. 97. 2003 Nov. pp. 1303-9.

(This paper compared single-injection versus continuous nerve blocks for major foot or ankle surgery. Patients who received continuous blocks had better pain control, higher satisfaction scores, and were able to be discharged earlier than patients who received a saline infusion in the sciatic perineural catheter.)

Blumenthal, S, Borgeat, A, Neudörfer, C, Bertolini, R, Espinosa, N, Aguirre, J. "Additional femoral catheter in combination with popliteal catheter for analgesia after major ankle surgery". Br J Anaesth. vol. 106. 2011 Mar. pp. 387-93.

(This study compares pain relief from a femoral perineural infusion of local anesthetic added to a sciatic perineural catheter versus the sciatic catheter alone. Patients who received the femoral catheter had less pain, used less opioid analgesics, and had higher satisfaction. These effects remained significant 6 months after surgery. To date, there has not been a similar study comparing a saphenous nerve block to a femoral block.)

SooHoo, NF, Krenek, L, Eagan, MJ, Gurbani, B, Ko, CY, Zingmond, DS. "Complication rates following open reduction and internal fixation of ankle fractures". J Bone Joint Surg Am. vol. 91. 2009 May. pp. 1042-9.

(This study analyzed a large California health care database to determine what the rates of complications are following ankle fracture, as well as factors that may be associated with an increased risk of complications. Complications such as death, pulmonary embolism, wound infection, and reoperation were rare. Increasing age, medical comorbidities (especially complicated diabetes and peripheral vascular disease), and open fractures were associated with an increased risk for complications.)

Guo, S, Sethi, D, Prakash, D. "Compartment syndrome of the foot secondary to fixation of ankle fracture: a case report". Foot Ankle Surg. vol. 16. 2010 Sep. pp. e72-5.

(This is a case report describing compartment syndrome of the foot which required fasciotomies. Other case reports of compartment syndrome have been described. Patients have had compartment syndrome in the leg as well as the foot. This is a rare complication but still needs to be considered by the surgeon and anesthesiologist.)

Hoff, WS, Bonadies, JA, Cachecho, R, Dorlac, WC. "East Practice Management Guidelines Work Group: update to practice management guidelines for prophylactic antibiotic use in open fractures". J Trauma. vol. 70. 2011 Mar. pp. 751-4.

(This paper is an update of the previous guidelines developed by the EAST (Eastern Association of Surgery for Trauma) workgroup. Studies on the choice of antibiotic as well as the timing and duration of administration are discussed, and the strength of recommendations is based on the quality of available evidence.)

Haverstock, BD, Mandracchia, VJ. "Cigarette smoking and bone healing: implications in foot and ankle surgery". J Foot Ankle Surg. vol. 37. 1998 Jan-Feb. pp. 69-74.

(This is a review paper discussing basic science research on the mechanisms by which tobacco smoke could lead to complications after ankle surgery. Other papers on the topic have examined the implications of other factors commonly associated with poor healing such as diabetes or chronic corticosteroid use. Another related paper discussed the role of the foot and ankle surgeon in smoking cessation.)

Fuzier, R, Hoffreumont, P, Bringuier-Branchereau, S, Capdevila, X, Singelyn, F. "Does the sciatic nerve approach influence thigh tourniquet tolerance during below-knee surgery". Anesth Analg. vol. 100. 2005 May. pp. 1511-4.

(This paper compares popliteal to subgluteal sciatic blocks used for surgical anesthesia. All patients had femoral blocks and the primary endpoint was tourniquet-related pain. The approach to the sciatic nerve did not affect the amount of pain, suggesting that more proximal approaches to the sciatic nerve may not be necessary for surgical anesthesia, even if the surgeons plan to use a thigh tourniquet. Other studies comparing thigh to calf or ankle tourniquets have shown less pain and hemodynamic changes for more distal tourniquets, and no increase in nerve dysfunction (peroneal nerve) with distal tourniquets if they are well-padded and placed appropriately (one hand-breadth below the knee).)
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