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LUMBAR MAGNETIC RESONANCE IMAGING (MRI) IN PRONE POSITION IN TETHERED CORD AND OCCULT TETHERED CORD
LUMBAR MRI IN PRONE POSITION and minimally invasive surgery of SECTION OF THE FILUM TERMINALE EXTERNUM (EXTRADURAL)
under local anesthesia in OCCULT TETHERED CORD
Our innovative diagnostic and minimally invasive surgery protocol was published in the scientific journal Pediatric Neurosurgery in 2020 and involves the combination of prone lumbar MRI and the extradural (externum) section of the filum terminale under local anesthesia.
This diagnostic-surgical protocol was described by us for the first time in the international medical scientific literature.
Patients operated on with this protocol are generally adult patients and to date there are over 200; the 4 adolescent patients operated on were the subject of the aforementioned scientific work.
In adult patients, occult tethered cord can present as a standalone pathology or in association with slightly descended cerebellar tonsils, 0-4 mm (LLCT), or Chiari malformation.
LUMBAR MRI IN PRONE POSITION
IN OCCULT TETHERED CORD
This scientific work from 2013 was published in an international medical journal by the Japanese colleagues from Hiroshima University.
Prone position Magnetic Resonance Imaging was used to identify the abnormal position of the filum at the lumbar intradural level in patients with OCCULT TETHERED CORD syndrome.
The Japanese colleagues compared a group of patients with occult tethered cord syndrome with a group of asymptomatic individuals.
Prone position Magnetic Resonance Imaging showed a significant difference in the position of the filum terminale between the two groups.
In patients with occult tethered cord syndrome, the filum did not move anteriorly with the nerve roots due to gravity but remained in a posterior position (SEE FIGURE AT THE TOP RIGHT, figure on the right).
In lumbar MRI in the prone position, if the filum terminale is not under tension it does not localize posteriorly and does not differ from the position of the nerve roots and cannot be the cause of the symptoms presented by the patient.
Obviously, the finding of the posterior position of the filum terminale cannot assess the intrinsic elasticity of the filum terminale itself but a tense filum terminale can pull the spinal cord to which it is connected, causing the symptoms found in OCCULT TETHERED CORD syndrome.
Since 2014, this examination has been part of the clinical-instrumental protocol adopted for our patients.
Prone position Magnetic Resonance Imaging makes it possible to support the clinical-anamnestic data.
At present, there are no other instrumental examinations that can provide this type of information. In this way, the risk of indicating surgery in patients with symptoms that, being generic and non-specific, may be due to other pathological situations is reduced.
IMAGE AT THE TOP LEFT:
- Abstract of the scientific work published in the Journal Neurosurgical Spine 2013.
IMAGE AT THE TOP RIGHT. Axial images of lumbar Magnetic Resonance Imaging in the prone position to assess the position of the intradural filum terminale:
- On the left: images of a healthy person from the control group;
- On the right: images of a patient with occult tethered cord syndrome. In patients with occult tethered cord syndrome, the filum terminale does not move anteriorly with the nerve roots due to gravity but remains in a posterior position (WHITE ARROWHEAD).
LUMBAR MRI IN PRONE POSITION
IN THE TETHERED CORD
AND IN THE RETETHERING
The American colleagues from the University of Chicago conducted a study in 2018 to evaluate the usefulness of lumbar MRI in the prone position in cases of TETHERED CORD and in SPINAL CORD RETETHERING.
They also evaluated a small group of patients with OCCULT TETHERED CORD who, however, are not included in the case analysis.
The American colleagues, in evaluating the percentage of movement of the conus medullaris in the supine and prone positions, conclude their work by stating that:
"In the present series, prone MRI proves to be a sensitive and specific tool and the authors believe it may have a role as a supporting test in the diagnosis of tethered cord or spinal cord retethering."
IMAGE AT THE TOP LEFT:
- Abstract of the scientific work published in Journal Neurosurg Pediatrics 2018.
IMAGE AT THE TOP RIGHT. Images related to the evaluation of the percentage of mobility of the conus medullaris (ventral conus motion):
- On the left, an example of how the aforementioned mobility of the conus medullaris is calculated.
- On the right, a negative exam in which there is a wide mobility of the conus medullaris not compatible with the presence of tethered cord.
LAST MODIFIED 28 FEBRUARY 2021
© Copyright 2020 Vanni VERONESI. All rights reserved.