Ventral and dorsal tethering bands of the spinal cord in the same patient: a case report

Double spinal cord tethering and congenital kyphosis in a 4-year-old boy

PURPOSE

Congenital kyphosis (CK) is an uncommon condition that develops due to a defect of formation or segmentation of one or more vertebrae during the first weeks of embryonic life and can be frequently associated with abnormalities of the spinal cord. Meningocele manqué (MM) is a rare congenital malformation consisting of intradural fibrous bands tethering the spinal cord, oftentimes in combination with a split cord malformation. The aim of this manuscript is to describe combined surgical management of a rare case of CK associated with double spinal cord tethering.

STUDY DESIGN

Case report.

METHODS

We report the case of a 4-year-old boy presenting with a combination of congenital kyphosis due to L2 fully segmented posterior hemivertebra and double spinal cord tethering, at the level of the filum terminale and at L1-L2 due to an intradural ventral fibrous band.

RESULTS

Spinal cord detethering and L2 hemivertebra resection with kyphosis correction were achieved with a single stage procedure. Segmental kyphosis was corrected from 45° to 11° post-operatively. Apart from a transitory sensory impairment, no immediate or delayed complications were noted and, at 2 years follow-up, correction and spinal alignment were stable.

CONCLUSION

To the best of our knowledge, this is the first case to report the simultaneous occurrence of congenital kyphosis and double spinal cord tethering due to MM and tethering of the filum terminale. Our case report shows that surgical correction of the deformity and spinal cord detethering can be safely and effectively achieved during the same surgical procedure.

Meningocele Manqué Discovered During Filum Terminale Resection in Occult Tethered Cord Syndrome

BACKGROUND

Meningocele manqué (MM) is characterized by tethering of the spinal cord, nerve roots, or filum terminale by fibrous attachments formed by atrophic or incomplete meningoceles. Patients with MM can present with symptoms of tethered cord syndrome (TCS).

CASE DESCRIPTION

We present the case of an MM discovered incidentally during microsurgical resection of filum terminale for occult TCS. The MM was not visible on the preoperative magnetic resonance imaging (MRI) studies. After L2-L3 laminotomy, an extradural mass was appreciated adherent to the spinal dura, which was found to be an MM. The nerve roots of the cauda equina were found to protrude through the dura, consistent with tethered cauda equina. After microsurgical resection of the filum terminale, the tethered cauda nerve roots were stimulated, and redundant electromyographic signals were detected at both the left- and the right-sided muscles of the lower extremities. Microsurgical repair of the MM was performed, assuming that the patient's symptoms of TCS would also be explained by the MM and that her symptoms would likely have been incompletely addressed by filum terminale release alone. A review of the preoperative 3-dimensional constructive interference in steady state MRI sequence revealed pathological features at the L2-L3 level suspicious for our intraoperative findings of an MM.

CONCLUSIONS

Surgeons planning filum terminale release for occult TCS should always be aware of the possibility of associated pathological features of tethering that might be overlooked. In retrospect, the detection of MM was enabled by the high-resolution 3-dimensional constructive interference in steady state MRI sequence. This finding advocates for the use of high-resolution MRI for patients undergoing evaluation for occult TCS to detect pathological features that might otherwise be undetected.