Case 17: lower extremity weakness after a fall

posted: April 6, 1997

Resident: Ian Angel, MD
Attending: Deepak Awasthi, MD

CLINICAL PRESENTATION: This 19 year woman presented to the ER after a 3 foot fall from a cemetry block. She complained of weakness and numbness of her right leg starting immediately after the fall. The weakness continued to progress to include the whole right leg. In addition, she described dyesthesias in her left leg. On arrival to the ER, she was stabilized and a foley catheter inserted with a100cc residual urine. Past medical history is significant for sudden back pain after lifting a patient (pt is a part-time nurse) approximately 6 months ago.

Clinical examination revealed right lower extremity weakness (proximal 2/5 > distal 3/5). There was decrease in propioception on the right with mild decrease in sensation to pinprick and light touch on the right. Left side was normal, but the patient described dyesthesias and hyperesthesias on the left lower extremity. Rectal exam was normal. Normal sensation in the perianal and perineal region. No clear cut sensory level other than possibly right L2.

What is your differential diagnosis? What diagnostic studies will you order?

Please comment: dawast@lsuhsc.edu

STEPS TAKEN AT LSU: Initial studies ordered were plain lumbar-sacral-thoracic x-rays: no fractures or subluxation/
The next study ordered was a MRI scan of the lumbosacral spine. A select sagital view is shown below:

Note the top of the MRI- which shows the pathology (red marker)- syrinx in the lower thoracic spine. This MRI points out the importance of looking at the edges of a diagnostic study.

This study was followed by a thoraic MRI scan with and without contrast:

Note the syrinx extending from T8 to T11 and then again in the conus (blue marker). The red marker indicates a ventral extradural lesion just above the disc space of T10-11- it looks like a "spike" and does not enhnace with contrast. Also note a select axial MRI image (T1WI):

This T1WI shows the extradural lesion (red marker) and the central syrinx. The ventral lesion is on the right side pushing the thecal sac to the left.

What would you do at this stage? Surgery v. no surgery? Surgical approach?

Please comment: dawast@lsuhsc.edu

STEPS TAKEN AT LSU: We felt that the syrinx and the ventral lesion were contributing to the patient's symptoms. The syrinx may have been congenital or post-traumatic. The ventral lesion was felt to be a bony anomaly or disc or possibly (but unlikely) a neoplasm.
T9-11 laminectomy was performed. The laminectomy was extended laterally at the T10 level. Intraoperative ultrasound was now utilized to locate the largest portion of the syrinx as well as the ventral mass. Below are sagital (left) and axial (right) views showing a dramatic view of the ventral extradural mass and the syrinx with the cord being displaced.

Sagital intraop ultrasound. Purple marker points to the ventral lesion. Note its extradural location and proximity to the T10-11 disc space (red marker). The white marker ponts to the syrinx.

Axial intraoperative ultrasound views- left is abnormal with the extradural lesion; right pict depicts a normal region. Note the dramatic dsplacement of the thoracic thecal sac from right to left.
At this point the extradural lesion was approached and resected. Intraoperative pict below:

Note the extradural lesion on the right of midline (adjacent to the dissector). This lesion was resected and intraoperatively appeared to be an extruded disc fragment- partial;y fibrotic and calcified.
After resection of the lesion, the dura was opened and the syrinx decompressed through a posterior myelotomy with subsequent syrinx-subarachnoid shunt- see intraop pict below:

Dura has been opened and a shunt catheter has been inserted into the syrinx and then channled into the subrachnoid space (near the top right of the pict).

Post-resection and shunt intraop ultrasound is shown below:

Post-resection and post-shunt intraop ultrasound shown decompression of the spinal canal- removal of the ventral lesion and presence of shunt catheter in the syrinx cavity.

POSTOPERATIVE COURSE: Patient had considerable improvement in her strength and sensation in the lower extremity. She had some difficulty with balnace and thoracic dyesthesias (about T10-11). The final pathology on the lesion was intervertebral disc material.

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