History and Examination
A 41 year old female presents to the outpatient clinic with a progressive history of lower extremity weakness. Her legs have progressively lost strength in the last few years to the point where she has been non-ambulatory for the past 2-3 months.
The patient has no relevant past medical history and no family history of any similar conditions. She relates that she had spinal surgery seven years ago for a “cyst” of some kind. Prior to that surgery she was having similar symptoms, which abated for a short time postoperatively and then began to recur.
Cranial nerves II-XII are intact
DTRs – 2+ upper extremities, 3+ lower extremities
Strength- 5/5 upper extremities
3/5 bilateral lower extremities
+ Clonus bilateral lower extremities
Slightly decreased pinprick sensation from T5 dermatome down
Preoperative Imaging from Prior Surgery
Current Imaging 1
Current Imaging 2
Current Imaging 4
1. Based on the information available, what is your presumed diagnosis?
2. What surgery will be required to address the pathology?
3. What are the next steps after exposure and dural opening?
4. Which of the following describes you?
5. I practice in one of the following locations:
Would have liked to know the previous surgery findings
Would like to see more detailed imaging
The MR imaging in this case is suggestive of a recollection of the previously-drained arachnoid cyst. In addition, the tenting and angulation of the spinal cord anteriorly raises the possibility of spinal cord herniation through an anterior dural defect. Often a CT myelogram will help to demonstrate cysts, herniation, and whether communication exists between the cyst and intradural CSF.
The myelogram shows more clearly what appears to be herniation anteriorly. This is likely causing a tethering phenomenon resulting in myelopathy. When considering the operative approach a laminectomy alone, like that used in the patient’s prior surgery, may not provide safe access to the anterior cord. A modified costotranversectomy or at least facetectomy will be required to visualize the anterior portion of the dura. A transthoracic approach is not required.
Surgical intervention aims to both relieve the tethering phenomenon and prevent re-tethering through the dural defect. Although suturing the defect is possible this is often not feasible. Sewing a patch or sling is an acceptable option if the anatomy will allow.Should this fail, increasing the length of the dural opening is also an accepted technique. The larger hole prevents the spinal cord from becoming trapped, and symptomatic CSF leak from the anterior opening is very rare in these cases.
- Barrenechea IJ, Lesser JB, Gidekel AL, Turjanski L, Perin NI. Diagnosis and treatment of spinal cord herniation: a combined experience. J Neurosurg Spine. 2006 Oct;5(4):294-302.
- Berg-Johnsen J, Ilstad E, Kolstad F, Züchner M, Sundseth J. Idiopathic ventral spinal cord herniation: an increasingly recognized cause of thoracic myelopathy. J Cent Nerv Syst Dis. 2014 Oct 1;6:85-91. doi: 10.4137/JCNSD.S16180. eCollection 2014.
- Watanabe M, Chiba K, Matsumoto M, Maruiwa H, Fujimura Y, Toyama Y. Surgical management of idiopathic spinal cord herniation: a review of nine cases treated by the enlargement of the dural defect. J Neurosurg. 2001 Oct;95(2 Suppl):169-72.
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