MRI Spine



Fig. 51.1
T1 and T2 MR image of the thoracic spine. (a) T1-weighted MR image of the thoracic spine in the axial view. (b) T1-weighted MR image of the thoracic spine in the sagittal view. (c) T2-weighted MR image of the thoracic spine in the sagittal view. (d) T2-weighted MR image of the thoracic spine in the axial view



A 38-year-old female has undergone an ORIF of the femur with a general anesthetic and epidural anesthesia for postoperative pain. On the second postoperative day, she is complaining of increasing back pain, numbness, and some weakness on the left leg. Her VSS show a blood pressure of 110/60 mmHg, HR 85, RR 14, T-38.8 C. The surgeon would like you to remove the epidural catheter. She is on aspirin and subcutaneous heparin 5000 units three times a day.


  1. 1.


    What does the MRI show you in this picture?

     

  2. 2.


    What is the incidence of this condition?

     

  3. 3.


    How does this condition present clinically?

     

  4. 4.


    What is the differential diagnosis for this patient?

     

  5. 5.


    What are its risk factors?

     

  6. 6.


    How could one prevent its occurrence?

     

  7. 7.


    What treatment options are available?

     



Answers


  1. 1.


    Figure 51.1A and B shows a fluid collection in the epidural space in the thoracic spine in a T1-weighted image in sagittal and axial views, respectively. Figure 51.1C and D shows a hyperintense mass at the same level in a T2-weighted image. Figure 51.1D shows an intense mass pushing on the anterior aspect of the spinal cord (white arrows). Spinal epidural hematoma can occur spontaneously or may follow spinal or epidural anesthesia [1]. The peridural anterolateral venous plexus usually is most often the primary source, though arterial sources of hemorrhage can occur rarely. This is supported by the fact that hematoma usually develops over hours to days suggesting a slow accumulation of blood from a venous bleed. The hematoma usually extends to the dorsal aspect of thoracic or lumbar region over several vertebral levels. If the patient has any contraindication to obtaining a MRI, then a CT myelography scan may be substituted to make an early diagnosis. MRI is however more specific in detecting the various stages of hematoma compared to CT myelography and is considered the first choice diagnostic step to confirm the presence of an epidural hematoma. An acute hematoma usually presents as low signal intensity signal on T1-weighted image and high signal intensity on T2-weighted image [2].

     

  2. 2.


    Epidural hematoma after neuraxial anesthesia is fortunately a rare event. The true incidence is unknown but is estimated to occur at an incidence of 1:220,000 after a spinal block and 1:150,000 after an epidural block [3]. The risk is much higher at 1 in 3000 in certain patients with risk factors. The risk is much lower in the obstetric population compared to vascular patients. About 1 in 430 patients with epidural catheters will be suspected to have an epidural hematoma and undergo a workup for it [4].

     

  3. 3.


    Patients with epidural hematoma present with severe unrelenting, nonpositional, acute onset back pain and varying degrees of lower-limb weakness and sensory deficits. Some patients may have motor weakness as a primary symptom in the absence of back pain [5]. If the compression is extensive, then it could cause bowel and bladder incontinence. Symptoms could be absent or attenuated in the presence of a well-functioning epidural catheter infusing high concentrations of local anesthetics. Symptoms rarely develop in the immediate postoperative period and typically take 2–3 days. Once symptoms begin, they can progress from back pain to a complete or partial paraplegia or even quadriplegia in a few hours [6].

     

  4. 4.


    The differential diagnosis for this presentation can include epidural abscess, intradural hemorrhage, prolonged and exaggerated neuraxial block, anterior spinal artery syndrome, spinal cord compression due to presence of tumors, disc herniation, worsening of previous spinal stenosis, lumbar radiculopathy, compression fracture of the spine, and spinal cord infarction. There should be a high index of suspicion for an epidural hematoma in an anticoagulated patient who has an epidural catheter and in the presence of back pain with neurological deficits.

     

  5. 5.


    The risk factors for developing an epidural hematoma include “patient-specific” factors or “surgery-related” issues. “Patient-specific factors” include advanced age, needle size, presence of epidural catheter, females, trauma patients, spinal cord and vertebral column abnormalities, preexisting spinal stenosis, organ function compromise, presence of underlying coagulopathy, traumatic or difficult needle placement, as well as indwelling catheter in anticoagulated patient. Spontaneous spinal epidural hematoma can sometimes occur with anticoagulation, thrombolysis, blood dyscrasias, coagulopathies, thrombocytopenia, neoplasms, or vascular malformations. “Surgery-related factors” include prolonged surgery and high intraoperative blood loss.

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Sep 23, 2017 | Posted by in Uncategorized | Comments Off on MRI Spine
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