A 67-year-old man was hospitalized yesterday following elective right knee arthroplasty for osteoarthritis. Medical history is notable for hypertension, type 2 diabetes, and coronary artery disease; the patient is receiving chronic antiplatelet therapy with clopidogrel, which was stopped 5 days prior to surgery. The procedure was performed under anesthesia via epidural and femoral nerve block, and no intraoperative complications were noted. Following surgery, patient-controlled analgesia was provided for pain control, and prophylactic enoxaparin was given beginning 12 hours after surgery completion. Today, the patient has had difficulty urinating after removal of the urinary catheter, as well as low back pain and numbness in the legs. Examination shows tenderness at the insertion site of the epidural catheter. The knee incision is clean with no bleeding or drainage. There is weakness of right plantar flexion and dorsiflexion. Sensation is decreased in the anterior thigh and leg bilaterally. Which of the following is the best next step in management of this patient?

Question

A 67-year-old man was hospitalized yesterday following elective right knee arthroplasty for osteoarthritis.  Medical history is notable for hypertension, type 2 diabetes, and coronary artery disease; the patient is receiving chronic antiplatelet therapy with clopidogrel, which was stopped 5 days prior to surgery.  The procedure was performed under anesthesia via epidural and femoral nerve block, and no intraoperative complications were noted.  Following surgery, patient-controlled analgesia was provided for pain control, and prophylactic enoxaparin was given beginning 12 hours after surgery completion.  Today, the patient has had difficulty urinating after removal of the urinary catheter, as well as low back pain and numbness in the legs.  Examination shows tenderness at the insertion site of the epidural catheter.  The knee incision is clean with no bleeding or drainage.  There is weakness of right plantar flexion and dorsiflexion.  Sensation is decreased in the anterior thigh and leg bilaterally.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

This patient with urinary retention, diminished sensation in the legs, and weakness of the right foot has evidence of cauda equina syndrome. In association with low back pain and recent spinal anesthesia, this presentation suggests a spinal epidural hematoma (SEH). SEH is a potential complication of neuraxial anesthesia (eg, epidural block), lumbar puncture, or spinal surgery. It is especially common in older adults taking antithrombotic medications, even when such drugs are appropriately discontinued periprocedurally, as in this patient. Additional risk factors include other coagulopathies (eg, thrombocytopenia), spinal structural abnormalities, and osteoporosis. Bleeding within the spinal canal results in cord compression, leading to progressive motor and sensory dysfunction in the distribution of the affected nerve root. Due to the typical insertion site of spinal needles in the lower lumbar spine, cauda equina syndrome with bowel and bladder dysfunction may occur. There is often localized back pain and point tenderness, and some patients may also develop radicular pain. The bleeding source is typically venous; therefore, symptoms are usually slowly progressive (ie, days). Management includes an urgent MRI of the spine to evaluate for blood within the canal. SEH is considered a surgical emergency and typically requires urgent decompression (eg, laminectomy). (Choice A) Compartment syndrome (indicated by elevated compartmental pressure) may occur as a surgical complication and can cause muscle weakness and diminished sensation. However, it typically initially causes severe pain in the extremity. Bilateral symptoms, urinary retention, and back pain is unexpected. (Choice B) Although opiates can cause urinary retention, this patient's neurologic deficits and low back pain are more consistent with cord compression, which requires further evaluation with imaging. (Choice D) Nerve conduction studies can be used to evaluate for nerve injury that occurred intraoperatively. Although common peroneal nerve injury causes foot drop and numbness of the dorsal foot, it would not cause weakness with plantar flexion, urinary retention, or bilateral sensory deficits. (Choice E) Mild pain at the epidural site is common and does not require further evaluation. However, severe pain and neurologic deficits raise concern for hematoma or spinal nerve injury and require further evaluation. Educational objective: Spinal epidural hematoma is a potential complication of neuraxial anesthesia (eg, epidural block), lumbar puncture, or spinal surgery and is more common in older adults taking antithrombotic medications. Manifestations include slowly progressive motor and sensory dysfunction and localized back pain; bowel and bladder dysfunction may occur. Management includes an urgent MRI and neurosurgical decompression.

A 67-Year-Old Man Was Hospitalized Yesterday Following Elective Right Knee