What the Anesthesiologist Should Know before the Operative Procedure?
The tibial plateau is defined as the enlarged, proximal end of the tibia including the medial and lateral condyles and the intervening intercondylar eminence; fractures of this primary weight-bearing surface of the leg require substantial force in healthy individuals, or less dramatic force in elderly patients with osteoporosis (Figure 1). The first group includes patients who incur direct blows to the leg as in athletic activities, trauma patients who suffer motor vehicle, vehicle-pedestrian trauma or gunshot wounds, and patients who sustain falls from heights and land on extended legs. The second group of elderly patients may have sustained only minor impact or falls. High force injuries, in particular, can be associated with disruption of the menisci and collateral and cruciate ligaments, and may result in dislocation of the knee.
Fracture/dislocations can result in neurovascular trauma to the popliteal vessels and sciatic nerve, and the assessment of pulses and distal nerve function should be noted by the anesthesiologist. A variety of orthopedic classification systems are used to categorize tibial plateau fractures (AO/OTA, Schatzker, Hohl and Moore), ± joint dislocation, but these classifications are mainly important for orthopedic repair, wound and rehabilitation management. The classification is not particularly pertinent to the anesthesia plan as long as the extent of injury, surgical approach and duration, and possible neurovascular injury and need for vascular repair are ascertained by the anesthesiologist preoperatively.
The primary “comorbidities” to consider in the otherwise healthy trauma patient are associated traumatic injuries such as head, spine, chest, abdomen and pelvic injuries with potential for occult blood loss, central nervous system (CNS) injury, pneumothorax, great vessel injury, or other organ damage. Although fracture management, especially open fracture (see below) is urgent, its management is secondary to the management of truly life-threatening injuries in these patients. Once the patient is stabilized, attention to the tibial fracture is appropriate. When a trauma patient presents to the operating room (OR) for ORIF of tibial fracture, the anesthesiologist must be vigilant for signs of traumatic injuries not detected on the primary or secondary trauma surveys.
The second tibial fracture group of elderly, osteoporotic individuals, present a different set of considerations due to age-related decline in organ function and the presence of medical disease. Usual preoperative assessment for cardiovascular, pulmonary, hepatorenal, endocrine, neurologic, and musculoskeletal disease in elderly patients applies. Rapid evaluation and optimization of medical condition may be needed before operative intervention. If the tibial fracture occurred from a fall, the history of the fall is important. If it was secondary to a syncopal event, then evaluation for cardiac structural or rhythm abnormalities, and cerebrovascular abnormalities may be necessary to address a perioperative risk of stroke. A full accounting of medications including anticoagulants is necessary to plan an appropriate regional or general anesthetic, as well as invasive monitoring as indicated.
Of course, elderly patients may also have been involved in high velocity motor vehicle or other trauma, and all the aforementioned considerations for trauma patients additionally apply.
Open tibial plateau fractures require urgent debridement to reduce infection risk, with soft tissue infection reported in over 20%, and osteomyelitis in over 5% with open tibial fractures. The tibia has a relatively poor blood supply and little soft tissue coverage anteriorly, and is more susceptible to infection than other long bones. The rate of infection is positively correlated with the extent of soft tissue injury and bone exposure, using the Gustilo classification. Conventional management recommends early antibiotic administration and tetanus prophylaxis, and wound coverage within 6 hours, although the data to support a specific time window is lacking. One recent study showed no difference in infection rate with surgery before or after 6 hours, although no patient developed infection if operated within 2 hours of injury. Tibial plateau fractures with a significant open component and contamination will commonly be treated with external fixation for stabilization with debridement and wound coverage, delaying definitive internal hardware fixation until the infection risk is lower (Figure 2).
Compartment syndrome is an important associated complication following tibial plateau fracture for the anesthesiologist to consider. Compartment syndrome is most likely to occur following tibial shaft (up to 8%), followed by tibial plateau fractures (1-2%), although it may also follow forearm, calcaneal, hand, and femur fractures. It has been reported as high as 14.5% following high energy, complex, bi-condylar tibial plateau fractures. Compartment syndrome of the leg can result in permanent disability, ischemic contracture or amputation. Since many patients with tibial fracture are in the first group of young previously healthy individuals, a missed compartment syndrome may have devastating quality-of-life and medico-legal consequences. This syndrome can occur even if the fracture is open, so the index of suspicion must remain high in this clinical group as well.
Compartment syndrome is a constellation of signs and symptoms resulting from an increase in tissue volume within a fascial compartment whose compliance is exceeded; once compartment pressure exceeds capillary pressure, ischemia of muscle and nerve within that compartment occurs. If the pressure is not reduced by incising and opening the fascial compartment to reestablish perfusion, necrosis will occur. The process of reestablishing perfusion can result in further complications due to release of myoglobin, potassium and lactate into the circulation which may result in renal failure, hemodynamic instability, and organ dysfunction. Compartment syndrome of the leg may occur from tibial fracture with bleeding and edema increasing compartment volume, but can also occur from edema following ischemia and reperfusion, crush or prolonged compression injuries, IV infiltration or toxin injection, and envenomization injuries; this discussion is limited to the first etiology.
The leg is anatomically at highest risk because it contains four compartments with relatively limited compliance (Figure 3). The deep posterior compartment is especially difficult to examine, and all four compartments will usually be surgically opened if there is suspicion that compartment syndrome is developing. The challenges of monitoring for compartment syndrome as well as complications of fasciotomy will be discussed in the intraoperative management section, but have a significant bearing on the choice of anesthesia and postoperative analgesia (see below). Suffice it to say that in 2016, there is no ideal monitor or criteria to diagnose compartment syndrome, and surgeons use a combination of clinical signs and symptoms, +/- direct pressure monitoring, to determine when a fasciotomy is indicated; even direct invasive monitoring of compartment pressures or the criteria for intervention is not universally accepted, or felt to be completely reliable (see below).
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
The ORIF of a tibial fracture may present as an emergent, urgent or elective surgical procedure depending upon the following factors.
Emergent surgery is necessary when life or limb loss is imminent, and immediate surgical control is needed to interrupt the path to morbidity or mortality. It is uncommon for ORIF of a tibial fracture, specifically the fracture repair, to be truly emergent, since even substantial bleeding from an open fracture can generally be controlled for patient stabilization. Development of compartment syndrome, however, as a result of the fracture as described above would be considered a true surgical emergency, and there is a significant risk of permanent limb injury or even limb loss if fasciotomy is not performed emergently. In addition, a tibial plateau fracture with popliteal artery injury and ischemia is an indication for emergent surgery for revascularization. The basic principles for management of the patient brought emergently to the OR apply. These principles include; identification of other injuries or medical problems, medications and allergies, assumption of full-stomach precautions, resuscitation and anesthesia as tolerated, and a goal to maintain critical organ perfusion and oxygenation.
Urgent: If the tibial fracture is open, then debridement of devitalized tissue and fracture stabilization externally or internally, and wound management is considered an indication for urgent surgery. It is suggested that a delay of definitive debridement of greater than 6 hours significantly increases the risk of infection, although data is lacking as mentioned above. These patients will have a more complete history and evaluation before presenting to the OR, and should have stable cardiopulmonary function, but are still generally considered to have a full stomach and may have significant other injuries.
Elective: Some tibial fractures with good alignment of the fragments may be managed with casting. If healing does not progress acceptably, those patients may be electively brought to the OR for ORIF some weeks after the initial injury. Nonunion or chronic osteomyelitis is another indication for elective exploration, debridement, possible removal of hardware if previously placed, and external fixation. Patients with open tibial fractures managed with external fixation and negative-pressure wound treatment devices will return to the OR semielectively for repeat debridement and ultimate internal fixation as well as wound coverage with primary closure, skin graft, or myocutaneous flap.
2. Preoperative evaluation
For the first group of patients, the previously healthy trauma patient, there are a number of factors to consider (see above) with respect to associated injuries when preparing for anesthesia for ORIF of the tibia. The scope of this chapter, however, is not intended to cover all the considerations for management of the trauma patient who presents urgently or emergently to the OR. Reference to other chapters on care of the patient with head injury, cervical or other spinal injury, chest and abdominal trauma or major hemorrhage is recommended. Initial management of tibial fractures may consist only of splinting/immobilization until other, more life-threatening injuries are addressed. Reduction and splinting of fractures are standard care to minimize continued vascular, nerve or tissue damage from bone fragment movement and disruption of normal anatomic positioning of the limb.
For the elderly patient with tibial fracture, attention must be paid to identifying other injuries occurring at the time of the tibial fracture such as wrist, shoulder, hip or head injury. It is presumed that the admitting physicians performed a comprehensive evaluation and diagnosed such other injuries, but delayed tenderness or swelling from wrist fracture may lead to a missed diagnosis until an IV is attempted at the site. More importantly, the history of a fall is important, and if abrupt dizziness or syncope was the inciting event as mentioned above, this may indicate cardiac or cerebrovascular disease that warrants investigation prior to non-urgent surgery. Fractures in the elderly patient may be pathologic, occurring at a site of a primary or metastatic tumor, although isolated tibial metastases and fracture are much less common than pathologic fractures of the femur or humerus.
For the elderly patient without other injuries or syncopal history, who requires ORIF of their tibial fracture as soon as they can be “medically optimized”, preoperative assessment and diagnostic testing should be performed to identify medical conditions or organ dysfunction requiring attention in the anesthetic planning to minimize the risk of perioperative complications. Some ways such assessment could impact the anesthetic planning for such a patient include performing a more limited surgical procedure of shorter duration, shorter tourniquet application, or less blood loss; applying more invasive monitoring; choosing an anesthetic approach specific to the organ dysfunction; or choosing a higher intensity of postoperative monitoring such as the intensive care unit.
Delaying surgery may be indicated if the patient has critical organ dysfunction which could lead to perioperative deterioration, or which requires urgent attention to prevent additional morbidity such as
pulmonary: pneumonia or COPD exacerbation with bronchospasm, hypoxemia or dyspnea at rest;
cardiac: acute myocardial ischemia or infarction, decompensated congestive heart failure, critical aortic stenosis, dysrhythmia such as atrial fibrillation with rapid ventricular response; (For cardiac problems, the indications for surgical delay, as well as non-invasive cardiac assessment are well-described in the American College of Cardiologists Guidelines for Perioperative Evaluation of the Patient Presenting for Non-Cardiac Surgery)
renal: acute renal failure with fluid overload, hyperkalemia, or acidosis;
CNS: cerebral ischemia, stroke, seizure, or delirium.
Once again, this chapter is not intended to be an exhaustive resource for evaluation of the geriatric patient who requires surgery, and will focus on problems specific to patients with tibial fracture.
A common problem associated with tibial fracture and lower extremity immobilization in both young and elderly patients is the high risk for deep venous thrombosis (DVT) and pulmonary embolism (PE). Within 24 hours of hospital admission, The Joint Commission requires that patients be assessed for their risk of DVT, and placed on recommended DVT prophylaxis unless contraindicated. Most patients, then, presenting for non-emergent ORIF of a tibial fracture will be on some anticoagulant medication which may have a bearing on choice of regional anesthesia (see below). Paradoxically, patients who were taking anticoagulant medications at the time of their tibial fracture (such as coumadin for atrial fibrillation) have a greater tendency to develop compartment syndrome from fracture bleeding, and those patients will be likely to have their anticoagulation medication actively antagonized before surgical intervention.
3. What are the implications of co-existing disease on perioperative care?
The co-existing diseases for patients with tibial fracture have been discussed above. To review, the young trauma patient may have significant other injuries due to the trauma. Elderly patient may have an inciting medical condition leading to a fall and tibial fracture, associated other injuries from the fall, or chronic or unstable medical conditions. The specific conditions associated with tibial fracture in both patient groups include DVT and lower extremity compartment syndrome, as well as infection occurring following open fracture.
b. Cardiovascular system
Significant pulmonary disease may be an indication for regional anesthesia, since ORIF of tibial fracture may be performed with either general or regional anesthesia. The potential for pulmonary morbidity is low with extremity surgery as opposed to abdominal, thoracic or spine surgery, although most feel the likelihood for bronchospasm is reduced if endotracheal intubation is avoided. More discussion of regional vs. general anesthesia follows.
In the setting of urgent or emergent ORIF of a tibial fracture, both trauma and pain are risk factors for retained gastric contents. These patients should be managed accordingly with either rapid sequence induction or awake intubation if general anesthesia is chosen.
When compartment syndrome and rhabdomyolysis develop and the leg is then re-perfused, significant amounts of myoglobin are released into the circulation and acute renal failure may result. Placement of an indwelling bladder catheter and monitoring of urine output for volume and color is indicated for these procedures. Although the scientific evidence of benefit is lacking, it is standard clinical practice to promote diuresis of >200 mL/h , commonly with isotonic crystalloid and, if necessary, mannitol, as well as alkalinization of the urine to a pH > 6.5 with sodium bicarbonate to reduce the risk of acute renal failure due to myoglobinuria. The mannitol and bicarbonate carry some risk of volume overload and hypernatremia/hyperosmolarity/alkalosis, however, and must be administered with this consideration to the risk and benefit assessment for the patient.
The two main issues (question of cerebrovascular event and neurologic dysfuntion associated with compartment syndrome) are discussed above.
Diabetes mellitus is not uncommon in the older patients suffering these fractures. Optimization of management and continued monitoring of glucose in the peri-operative period is important to enhance wound healing, recognizing that the stress of surgery affects blood glucose levels. Both diabetes, and hyperglycemia (>200-220 mg/dL) without a history of diabetes, have been identified as risk factors for wound infection following orthopedic trauma.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
4. What are the patient’s medications and how should they be managed in the perioperative period?
See all comments above.
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
The routine use of prophylactic anticoagulation medication in patients at risk for DVT with tibial fracture has been discussed above. The consideration for anesthetic choice (particularly neuraxial anesthesia) while on these medications will be discussed below. This may include medications specific to diseases associated with surgery.
i. What should be recommended with regard to continuation of medications taken chronically?
The usual medications recommended in current perioperative practice to be continued.
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.
l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]
Closed fractures of the tibia requiring fixation carry a risk of wound infection, and routine antibiotic prophylaxis is recommended. First or second-generation cephalosporins such as cephazolin are recommended by national guidelines for prevention of surgical site infections, with alternative clindamycin or vancomycin for patients with severe allergic reaction to penicillins or cephalosporins. The procedure will most commonly be performed with a thigh tourniquet to minimize surgical bleeding, and in this situation, it is required that the entire antibiotic infusion be completed before inflation of a tourniquet, to establish adequate tissue levels of the antibiotic. Because of this time constraint, antibiotics requiring an hour for infusion such as vancomycin or ciprofloxacin must be started in the preoperative area to be compliant with current guidelines. (www.icsi.org) (www.qualitymeasures.ahrq.gov)
For open fracture (Class IV dirty wound), antibiotic treatment is likely to have been initiated prior to arrival to the OR for debridement. This is considered treatment, rather than wound prophylaxis.
m. Does the patient have a history of allergy to anesthesia?
Malignant hyperthermia (MH)
Documented: Avoid all trigger agents such as succinylcholine and inhalational agents:
Proposed general anesthetic plan:
Ensure MH cart available: [MH protocol]
Family history or risk factors for MH:
Local anesthetics/ muscle relaxants: If regional anesthesia is chosen, for peripheral nerve block or neuraxial anesthesia, patients may claim prior allergy to local anesthetics. A history of the allergic event should be obtained, and most commonly the history will suggest vasovagal reaction with bradycardia and syncope, or reaction to epinephrine administered along with the local anesthetic resulting in anxiety, tremor, or palpitations. Patients will sometimes have true allergic reaction to the preservatives formulated with local anesthetics, or to the metabolite of the aminoester local anesthetics para-aminobenzoic acid (PABA). True allergy to preservative-free amino-amide local anesthetics is exceedingly rare, and these can generally be employed with minimal risk.
5. What laboratory tests should be obtained and has everything been reviewed?
No specific laboratory tests are indicated for this procedure beyond those suggested by the preoperative assessment described above.
What are the options for anesthetic management and how to determine the best technique?
The ORIF of a tibial plateau fracture is typically performed in the supine position on an x-ray compatible table (“fluoro table”), using a thigh tourniquet to minimize surgical bleeding unless compartment syndrome is already present. In the latter case, the tourniquet is not inflated so that the presence of bleeding and assessment of the color of muscle tissue can be made to determine whether necrosis has occurred, and the extent of devitalized muscle that should be debrided. The surgical procedure duration ranges from 1.5-3 hours, depending upon the degree of comminution and complexity of the repair. The common surgical approach is to affix a plate(s) with screws after elevation of the condylar surface to re-establish the knee joint (Figure 4). Liberal use of fluoroscopy should be expected for fracture reduction and assessment of hardware placement and adequacy of repair; the patient and anesthesia providers should have lead shielding as appropriate. A rare intraoperative complication that has been described is pulmonary embolism occurring from an existing DVT during movement of the patient from stretcher to OR table, or during leg manipulation and splint removal; this diagnosis should be considered if abrupt respiratory and/or cardiovascular deterioration occurs.
The considerations for both intraoperative anesthesia, and options for postoperative analgesia cannot be described without attention to the risk and monitoring for compartment syndrome, and how this affects the choice of anesthesia and analgesia.
The highest risk period for development of compartment syndrome following tibial fracture is within the 24-36 hours after the injury, and has been shown by some investigators to be a risk for a similar period after the surgical manipulation and repair. The challenge for anesthesia and analgesia selection is that there is no single accepted test which is sufficiently objective, sensitive and specific for the diagnosis of compartment syndrome. Such a test is needed to trigger intervention before tissue injury occurs. Pulses and a normal motor exam are usually maintained until advanced compartment syndrome develops; if the diagnosis is delayed until paralysis or pulselessness occur, then the likelihood of recovery of normal function is much lower than with an earlier diagnosis. Paresthesia or numbness may, however, be an earlier sign of nerve ischemia in a developing compartment syndrome.
The most important symptom is “pain out of proportion to expectations,” but this is so variable between patients and affected by other injuries, that it cannot be quantified and is therefore unreliable. Escalating requirements for pain medications is suggestive, as is the sign of pain with passive stretch of the calf or anterior musculature (although the patient has a fracture and pain with movement is expected). Surgeons will monitor for the subjective sign of “tightness” of the muscles of the calf or the anterior and lateral compartments, and this coupled with increasing pain is an indication for fasciotomy or more frequent serial examinations as the suspicion increases. The ability of orthopaedic residents and faculty, however, to manually assess elevated compartment pressure by palpation in a cadaver leg simulation model was poor, although detection of increasing pressure with serial exam was not tested. In another cadaver simulation study, even measurement of compartment pressures with common catheter equipment by orthopaedic physicians had poor accuracy.
Finally, direct monitoring of the pressure in one or all compartments is recommended by some, and continuous monitoring of the anterior compartment advised by some clinicians as unlikely to be normal with elevated pressure in the other compartments. Unfortunately, the criteria for making the diagnosis are not established, with some using an absolute compartment pressure greater than 30 or 40 mm Hg, and some using a (mean or diastolic blood pressure-compartment pressure), or “delta pressure” of less than 30 (some recommend 20 or 40).
Because of a lack of agreement on the value and application of these pressure measurements, however, surgeons prefer to combine all data including symptoms, physical exam, and, sometimes compartment pressure to make a decision to perform fasciotomy. An algorithm for repeated assessment and treatment was developed at the Hospital for Special Surgery and has been proposed (2014) particularly to address continuing evaluation after handoff of care.
In the only prospective, randomized study of compartment monitoring combined with clinical exam in 200 trauma patients with tibial fracture, 3% underwent fasciotomy overall, but 18% of monitored patients had elevated compartment pressure (delta p< 30) but did not undergo fasciotomy because other signs and symptoms were reassuring; no patient developed compartment syndrome or permanent disability. The authors concluded there was no benefit of monitoring if patients were responsive enough for clinical exam. The decision to perform fasciotomy cannot be made lightly since morbidity has been described from the procedure in a level 1 trauma center including prolonged hospital stay for wound closure, infection and 6% rate of superficial peroneal nerve injury.
There is a compelling need to develop sensitive and specific monitors to detect the onset of compartment syndrome, and there continues to be progress in this area. The application of near-infrared spectroscopy (NIRS) to monitor tissue and muscle oxygenation has been shown to be more specific in detecting compartment syndrome than compartment pressure monitoring, although the depth of measurement is shallow, and the technology has not yet gained a strong evidence-base in patient care to be widely adopted. Ultrasound has been applied in various forms to assess compartment compliance, specifically a change in compartment volume with specific probe pressure, and cadaver modeling has been tested, but like NIRS, this technology is under investigation, and not yet clinically in use. Finally, changes in arterial flow in arteries proximal a developing compartment syndrome has been demonstrated, specifically the diastolic reversal of flow, and this is also under investigation.
Clearly, since there is no definitive test at present, and surgeons use pain and function to monitor for impending compartment syndrome, a decision to provide prolonged and profound analgesia must be made in concert with the surgeons.
Many case reports and case series have detailed a delayed diagnosis of compartment syndrome in patients with neuraxial analgesia, peripheral nerve block, IV PCA analgesia where escalating opioid use was not recognized, and conventional prn opioid administration. An orthopedic expert on this subject, TE Whitesides, published an editorial on the controversy entitled “Pain: Friend or Foe?” in which he advocated against aggressive analgesia without attention to its source or pattern. On the other hand, the literature also contains many case reports in which pain due to compartment syndrome escalated and “broke through” the neuraxial analgesia or peripheral nerve block analgesia and was detected successfully. This has prompted some anesthesiologists to argue against the prohibition of regional blocks in at-risk patients. Until there is a reliable and objective test for compartment syndrome, however, there remains a potential for clinicians to ascribe changing neurologic symptoms in a limb to a regional block, or even treat increasing pain with increasing local anesthetic for a time, and a delay in diagnosis is potentially then increased in the setting of a regional block.
Therefore, at the present time, many surgeons prefer no prolonged local anesthetic blocks of sufficient intensity to potentially mask pain escalation due to compartment syndrome, at least for the critical period of up to 24-36 hours after injury or surgical repair. Avoiding even prolonged spinal analgesia is requested by surgeons at our institution.
Certainly, the absence of compartment syndrome in the postanesthesia care unit (PACU) does not obviate the risk, since postoperative edema and bleeding may continue to raise compartment pressures. Consultation with the surgeon is the appropriate course to determine when he/she feels the patient is beyond the risk period, and analgesia with local anesthetic block may be provided. Some anesthesiologists place perineural catheters at the time of surgery, but do not activate those catheters until the risk of compartment syndrome is past. Obviously, if anesthesiologists are managing postoperative pain with any technique during the risk period in patients following ORIF of tibial fracture, and pain is out of proportion to expectations, it is incumbent upon them to notify the surgeons and have them evaluate the patient, loosen dressings, reposition the limb and rule out developing compartment syndrome before the anesthesiologist elects to increase the analgesic medication.
Once again, because of the disability, medical, and medicolegal consequences of missed compartment syndrome, the critical message is that open communication with the surgeons is mandatory.
If 4-compartment fasciotomy has been performed, it is no longer rational to withold effective neuraxial or perineural analgesia since the syndrome has been treated, and repeated monitoring is no longer necessary; still some surgeons prefer to have the reassurance of normal neurologic function after fasciotomy which is dependent upon resolution of the local anesthetic block.
a. Regional anesthesia
Regional anesthesia for ORIF of a tibial plateau fracture may be indicated (see below), including spinal anesthesia, lumbar epidural anesthesia, or combined spinal/epidural anesthesia after discussion with the surgeons as to the expected duration of local anesthetic block and need to evaluate the patient postoperatively for compartment syndrome as discussed above. Long-acting single-shot blocks are typically avoided because they prevent evaluation unless fasciotomy is a planned part of the procedure, but if selected, then a lumbar plexus and proximal sciatic block will be necessary due to the thigh tourniquet requirements.
The ubiquitous use of antiplatelet and anticoagulant medication prehospitalization, particularly in the geriatric patient, as well as the common application of anticoagulation for DVT prophylaxis once hospitalized must be considered prior to regional anesthesia for tibial fracture. For neuraxial block and deep peripheral nerve or plexus block, the ASRA Consensus Statement is the reference document (www.asra.com), and should be reviewed to make a risk-benefit analysis for the specific patient. In the absence of pre-hospital medications or other inhibitors of coagulation, and with the most common current method of DVT prophylaxis with enoxaparin 30 mg SC q12h, it is recommended that the risk of spinal hematoma is not increased if a period of 10-12 hours has elapsed from the last dose to the neuraxial block in patients with normal renal function.
Difficult or traumatic placement, and epidural rather than spinal anesthesia with small gauge needle increase the bleeding potential. The same recommendations, albeit with less evidence base, are made for deep blocks such as lumbar plexus and possibly proximal sciatic block due to the difficulty of monitoring the site or compressing for bleeding, although some anesthesiologists feel this is too conservative and proceed with blocks at these sites in the presence of coagulation abnormalities.
Neuraxial anesthesia has advantages in particular patient populations, and the level of block need only reach L1 to provide anesthesia and muscle relaxation for lower extremity surgery with a thigh tourniquet. This level can be achieved without significant hemodynamic instability and excessive fluid requirements to maintain preload. A common selection with good prevention of tourniquet pain is isobaric bupivacaine, 12.5-15mg, combined with fentanyl 10-20 mcg, and epinephrine 200 mcg may prolong the block in the lumbo-sacral dermatomes without prolonging time to 2-segment regression.
Isobaric bupivacaine is not FDA-approved for spinal anesthesia in the United States, although there is a very large clinical experience with this drug in Europe and off-label in the United States. The time to recovery of sensation is likely to be similar to the time to alertness and evaluation following general anesthesia for the same procedure, and this may be shortened by reducing the local anesthetic dose or omitting the epinephrine if the surgeon predicts the procedure will take less time than average. Placement of a continuous lumbar epidural anesthetic is one variation on neuraxial block which allows for titration of a short-acting local anesthetic to the duration of the procedure, but requires a larger needle and incurs a delay in onset of anesthesia in the required L5-S1 dermatomes.
Combined spinal-epidural anesthesia allows for the dense and rapid onset of lower extremity anesthesia using a shorter duration of spinal drug, and has the flexibility to adapt to the duration of the surgery; disadvantages include a larger needle with more potential for trauma, and a possibility that the epidural catheter may not be placed properly to continue to provide surgical anesthesia when required. Advantages of neuraxial anesthesia are seen in patients with CNS injury, and pulmonary or cardiac disease:
CNS – For patients in cervical immobilization for known or possible cervical spine injury, neuraxial anesthesia is highly successful and avoids the alternative awake intubation that may be necessary depending on the injury. For patients with closed head injury without ICP monitor, neuraxial anesthesia (as long as there is no intracranial hematoma or other mass lesion) will allow for close monitoring of level of consciousness and CNS function.
Pulmonary – Avoiding endotracheal intubation by performing neuraxial anesthesia reduces the risk of bronchospasm in patients with pneumonia, COPD or reactive airway disease, and minimizes ventilatory depression from residual inhalation anesthetics, muscle relaxants and opioids that may occur following general anesthesia.
Cardiac – In patients with poor ventricular function and heart failure, neuraxial block avoids the negative inotropic effects of general anesthesia, and reduces preload and afterload which may improve ventricular performance.
There are potential disadvantages to the selection of neuraxial anesthesia for ORIF of a tibial plateau fracture, the first being that the patient must be positioned (usually lateral) for the performance of the block, and depending on the extent of injury this may be quite painful and require significant IV analgesics. The next most obvious disadvantage is that the spinal may not provide adequate anesthesia, or adequate duration of anesthesia to complete the procedure. In this case, conversion to general anesthesia may be required negating the advantages for the select patient populations listed above. The patient will be supine, such that access to the airway is unimpeded, but interruption of surgery is necessary and tourniquet time continues to accrue while the airway is secured.
Similarly, if the patient has other injuries and/or becomes uncomfortable in the surgical position, they may require heavier sedation or general anesthesia even if the block is adequate for the surgical procedure. Side effects and complications of neuraxial anesthesia may include high block with hypotension, bradycardia and nausea or vomiting, and postoperative postdural puncture headache, and the issues of rare spinal bleeding and interference with postoperative evaluation for compartment syndrome have been discussed.
Peripheral nerve block may be considered as the primary anesthetic, and has an advantage over neuraxial anesthesia of more limited hemodynamic effect and predictable extent of blockade, and the issues of single-shot block with respect to compartment syndrome and bleeding have been discussed above. Continuous sciatic block with continuous or single-shot lumbar plexus block, using an intermediate duration local anesthetic such as mepivacaine 1.25%-1.5% with epinephrine 1:200-300,000 should provide dense surgical block with resolution for monitoring within 4-5 hours. The blocks could be re-activated after an appropriate period of postoperative monitoring and communication with the surgeon. In general, though, two peripheral nerve blocks have a lower surgical success rate than spinal anesthesia, and the nonoperative leg may become uncomfortable during surgery such that conversion to general anesthesia is more likely than with spinal anesthesia. Peripheral nerve block may be considered as an adjunct to general or spinal anesthesia for postoperative analgesia, but this was discussed above, and will be reviewed below in the postoperative analgesia section.
b. General Anesthesia
There are particular benefits and advantages to general anesthesia for this procedure, the first being that the patient does not require potentially painful movement to induce anesthesia, and often general anesthesia can be induced in the OR while the patient is still on their bed, and they can then be moved painlessly to the OR table. Patient discomfort or agitation during surgery is prevented, and the duration of the anesthetic can be tailored to the duration of the surgery.
A general anesthetic can be adapted to unexpectedly long or short procedures with less difficulty than neuraxial anesthesia (unless a large dose of muscle relaxant is given precluding reversal after a short procedure.) The airway and ventilation and oxygenation are controlled if an endotracheal tube is placed, although for elective procedures without concern for full stomach, a pharyngeal airway and spontaneous ventilation may be considered. Profound muscle relaxation is generally not necessary for ORIF of a tibial fracture compared to femoral fractures with quadriceps spasm, for example. Neurologic function of the injured extremity can be assessed immediately after surgery unlike regional anesthesia techniques.
The disadvantages are the converse of the advantages for regional anesthesia. The patient with CNS dysfunction cannot be assessed until recovery from general anesthesia, and the patient with cervical fracture may require placement of the endotracheal tube using sedation and topical anesthesia prior to the induction of general anesthesia. The patient with severe ventricular dysfunction will have dose-dependent reduction of ventricular performance with inhalation anesthesia. For some cardiac disease such as critical aortic stenosis or pulmonary hypertension, many feel that general anesthesia with invasive monitoring of arterial pressure and, perhaps central pressures, allow the anesthesiologist more ability to titrate the anesthetic and vasoactive medications to hemodynamic effect and also maintain perfect blood gases than the more abrupt and less controllable changes in hemodynamics and ventilation that occur with neuraxial anesthesia.
Patients with pulmonary disease have a higher pulmonary complication rate following general than regional anesthesia, although the evidence for this is more compelling for abdominal surgery than extremity surgery. Nausea, vomiting and pain are more common following general than regional anesthesia, and prophylactic antiemetics may be indicated, as well as some intraoperative administration of opioid that will persist beyond emergence. The ORIF of a tibial fracture commonly results in moderate to severe pain, and this must be managed immediately upon emergence, sometimes with an agitated patient, while preserving the ability to assess the patient for possible compartment syndrome. The pain and adrenergic discharge on emergence from general anesthesia for this surgery may produce ischemia in patients with coronary artery disease, and should be treated expeditiously with analgesics and, possibly, adrenergic blocking drugs.
c. Monitored Anesthesia Care
MAC is not an option for surgical anesthesia unless, perhaps, the patient is insensate from a spinal cord injury, but care of this type of patient is beyond the scope of this chapter.
6. What is the author’s preferred method of anesthesia technique and why?
At Wake Forest University in 2016, the most common anesthetic chosen for ORIF of tibial fracture is general anesthesia, with a moderate dose of intraoperative opioid such as morphine or hydromorphone to control pain in the immediate postoperative period. A peripheral nerve catheter (sciatic) may be employed if the patient has had fasciotomy, and/or is returning to the OR for wound management following fasciotomy and has poorly controlled pain or will require frequent postoperative dressing changes. More commonly, if the patient requires close and frequent monitoring due to the risk of compartment syndrome, we generally do not perform continuous perineural block per our surgeons’ preferences. For particular patient groups as indicated above, spinal anesthesia is the next most common primary anesthetic, with drugs chosen to allow for assessment of the extremity reasonably soon following surgery.
What prophylactic antibiotics should be administered?
The usual prophylactic antibiotics administered for ORIF tibial fracture are discussed above, and since a tourniquet is commonly used for ORIF tibia, the entire dose of antibiotic should be administered prior to inflation of the tourniquet.
What do I need to know about the surgical technique to optimize my anesthetic care?
Patients are placed in the supine position, usually on a fluoroscopy-compatible table, and the surgical procedure may require 1.5-3 hours depending upon the complexity of the fracture. A thigh tourniquet is routinely used unless there is already concern for tissue ischemia. A longitudinal incision is usually made anterolaterally, posteromedially or both for internal fixation. For severe open injuries with contamination of tissue, reduction and external fixation may be employed to align and stabilize the fracture with irrigation and debridement of open wounds; these patients will likely return to the OR for repeated washout and eventual wound closure.
The most severe injuries actually have a lower risk of compartment syndrome due to the tissue disruption than less severe, closed injuries, but compartment syndrome is reported in open fractures as well and cannot be ignored. Occasionally, for more limited injuries an arthroscopic approach with screw fixation is chosen, but this chapter addresses the most common presenting injury and surgical approach.
What can I do intraoperatively to assist the surgeon and optimize patient care?
Patient immobility and modest muscle relaxation for exposure are surgical expectations. If muscle crush or compartment syndrome are diagnosed, monitoring urine output and treatment to minimize pigment-induced renal injury is indicated as described above.
What are the most common intraoperative complications and how can they be avoided/treated?
For the trauma patient brought urgently to the OR, cardiovascular deterioration due to unrecognized injury or bleeding may occur; invasive monitoring, frequent reassessment and laboratory analysis of hemoglobin and acid-base status, and a high index of suspicion is recommended. The more elective patient brought to the OR after a delay is at risk for pulmonary embolism with movement or fracture manipulation before the tourniquet is inflated, or later after it is deflated. Prolonged tourniquet time will predictably lead to modest decrease in pH, oxygenation and hypotension when the tourniquet is deflated; most patients tolerate this well unless they have marginal cardiopulmonary reserve.
b. If the patient is intubated, are there any special criteria for extubation?
None beyond the usual criteria for this surgical procedure
c. Postoperative management
What analgesic modalities can I implement?
As described in detail above, the choice for analgesia will depend upon communication with the surgeon to discuss analgesic requirements relative to the need for monitoring for compartment syndrome.
The procedure of ORIF of tibial plateau fracture is expected to cause moderate to severe pain, but most surgeons prefer no local anesthetic be administered in peripheral or neuraxial block in the immediate postoperative period, if continued and repeated observation is indicated. Systemic opioids on as-needed basis is most common, with attention to increasing pain and analgesic requirement. There is evidence that multimodal analgesia with scheduled acetaminophen, preoperative gabapentin, and nonsteroidal anti-inflammatory drugs (NSAIDs) reduce opioid requirements by approximately one third. The nonselective NSAIDs, however, show laboratory evidence of impaired bone fusion, and some surgeons prefer to avoid perioperative administration of these drugs when fracture union is the goal. If compartment syndrome is not a risk, then perineural analgesia or neuraxial analgesia with local anesthetic can provide superior analgesia and fewer side effects than systemic opioids.
What level bed acuity is appropriate?
The level of acuity for postoperative observation will be determined by the medical condition of the patient, since isolated ORIF of tibial fracture by itself is not an indication for more than standard postoperative nursing care or observation, beyond the added observation for compartment syndrome.
What are common postoperative complications, and ways to prevent and treat them?
The early postoperative complications of compartment syndrome and DVT have been discussed above. Fat embolism syndrome may occur postoperatively, although it is more likely with tibial or femoral shaft fractures, or intramedullary long-bone nailing than with tibial plateau fractures. Fat embolism syndrome (FES) is thought to result from central embolization of fat and marrow fragments from such injuries, with evidence of systemic embolization as well. The signs of petechiae, tachycardia, hypoxemia, and confusion should prompt consideration of the diagnosis. The development of FES often requires transfer to a higher level of (intensive) care, support of oxygenation, and assessment for coagulopathy which may develop.
Late postoperative complications include infection and non-union of the fracture, as well as degenerative arthritis from disruption of the knee joint and its repair; all three are likely to require operative intervention weeks to years after the original fracture surgery.
What’s the Evidence?
WHAT THE ANESTHESIOLOGIST SHOULD KNOW BEFORE THE OPERATIVE PROCEDURE
Canale, TS, Beaty, JH. “Tibial plateau fracture”. Campbell’s operative orthopaedics. 2008. pp. 3146-3160. (This orthopedic surgical text provides a resource for the classification, management, techniques and complications from the surgeon’s perspective.)
Khatod, M, Botte, MJ, Hoyt, BD. “Outcomes in open tibia fractures: Relationship between delay in treatment and infection”. J Trauma. vol. 55. 2003. pp. 949-954. (This is a useful reference for the anesthesiologist in discussing delay of surgery for medical optimization balanced with urgency of wound closure for open tibial fracture.)
Park, S, Ahn, J, Gee, AO. “Compartment syndrome in tibial fractures”. J Orthop Trauma. vol. 23. 2009. pp. 514-518. (This is a large retrospective review of patients with tibial fractures describing the incidence and contributing factors for compartment syndrome.)
Fleisher, LA, Beckman, JA, Brown, KA. “2009 ACCF/AHA Focused update on perioperative beta blockade incorporated Into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery”. J Am Coll Cardiol. vol. 54. 2009. pp. e13-e118. (This is the definitive practice guideline providing evidence-based recommendations on preoperative evaluation and management of many cardiovascular conditions in patients presenting for noncardiac surgery.)
Harris, IA, Kadir, A, Donald, G. “Continuous compartment pressure monitoring for tibia fractures: does it influence outcome”. J Trauma. vol. 60. 2006. pp. 1330-1335. (This reference describes the only prospective, randomized assessment of the value of continuous compartment monitoring, and showed no benefit in patients who could cooperate with a clinical exam. A significant number of patients (18) had delta pressure measurements <30 mm Hg, but with reassuring exam did not undergo fasciotomy and had no delayed development of compartment syndrome.)
Large, TM, Agel, J, Holtzman, DJ, Benirschke, SK, Krieg, JC. “Interobserver Variability in the Measurement of Lower Leg Compartment Pressures”. J Orthop Trauma. vol. 29. 2015 Jul. pp. 316-21. (This study demonstrates difficulties in application and accuracy of pressure monitoring for detection of compartment syndrome.)
Kashuk, JL, Moore, EE, Pinski, S. “Lower extremity compartment syndrome in the acute care surgery paradigm; safety lessons learned”. Patient Safety in Surgery. vol. 3. 2009. pp. 1-6. (This reference highlights the potential for missed diagnosis of compartment syndrome as well as the complications of fasciotomy, even in a busy trauma center with significant experience.)
Garner, MR, Taylor, SA, Gausden, E, Lyden, JP. “Compartment syndrome: diagnosis, management, and unique concerns in the twenty-first century”. HSS J. vol. 10. 2014 Jul. pp. 143-52. (This literature review and review article is a relatively complete and current description of compartment syndrome, and proposes an institutional algorithm for serial evaluation and management of patients at risk.)
Shadgan, B, Menon, M, O’Brien, P. “Diagnostic techniques in acute compartment syndrome of the leg”. J Orthop Trauma. vol. 22. 2008. pp. 581-587. (This is a good review of a number of diagnostic modalities used in the assessment of patients at risk for compartment syndrome.)
Gentilello, LM, Sanzone, A, Wang, L, Liu, PY, Robinson, L. “Near-infrared spectroscopy versus compartment pressure for the diagnosis of lower extremity compartmental syndrome using electromyography-determined measurements of neuromuscular function”. J Trauma. vol. 51. 2001 Jul. pp. 1-8. (This reference details the comparison of NIRS to Pressure Monitoring in a volunteer study.)
Mar, GJ, Barrington, MJ, McGuirk, BR. “Acute compartment syndrome of the lower limb and the effect of postoperative analgesia on diagnosis”. Br J Anaesth. vol. 102. 2009. pp. 3-11.
Davis, ET, Harris, A, Keene, D. “The use of regional anaesthesia in patients at risk of acute compartment syndrome”. Injury, Int J Care Injured. vol. 37. 2006. pp. 128-133. (These two references aptly demonstrate both sides of the pro-con debate on analgesia in the literature. The first editorial discusses the lack of evidence for analgesic techniques interfering with the diagnosis of compartment syndrome, which is a common theme in anesthesiology case reports. The second provides the orthopedic viewpoint that regional block may delay diagnosis. My opinion in reviewing the material is that the clinical exam requiring intact sensorimotor function is still highly valued, particularly for its negative predictive power in the setting of equivocal other signs such as isolated elevated compartment pressure. If compartment pressures alone are used, many unnecessary fasciotomies will be performed with potential for morbidity. Until better techniques for early identification of developing compartment syndrome are in widespread use, the anesthesiologist should defer to the surgeon who must determine when the patient is, or is no longer at risk, and when local anesthetic blocks are acceptable.)
Horlocker, TT, Wedel, DJ, Rowlingson, JC. “Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine evidence-based guidelines (Third Edition)”. Reg Anesth Pain Med. vol. 35. 2010. pp. 64-101. (This practice guideline is a necessary resource for the anesthesiologist considering regional anesthesia in a patient with tibial fracture receiving prophylactic or therapeutic anticoagulation. A draft interim update since this 2010 publication is available on the ASRA website, but has not yet been published.)
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- What the Anesthesiologist Should Know before the Operative Procedure?
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- 4. What are the patient’s medications and how should they be managed in the perioperative period?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How to modify care for patients with known allergies?
- l. Does the patient have any antibiotic allergies- - Common antibiotic allergies and alternative antibiotics]
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- Intraoperative Management:
- What are the options for anesthetic management and how to determine the best technique?
- 6. What is the author’s preferred method of anesthesia technique and why?
- What prophylactic antibiotics should be administered?
- What do I need to know about the surgical technique to optimize my anesthetic care?
- What can I do intraoperatively to assist the surgeon and optimize patient care?
- What are the most common intraoperative complications and how can they be avoided/treated?
- a. Neurologic:
- b. If the patient is intubated, are there any special criteria for extubation?
- c. Postoperative management