Level of termination of the spinal cord and the dural sac
: a magnetic resonance study.
(18) placed 1 mg morphine-impregnated microfibrillar collagen sponge over the intact dural sac
during single level posterior lumbar laminectomy and instrumented fusion operation and found that postoperative morphine consumption is lower than the control group during 24 h.
Although MED can directly remove intervertebral disc tissue protruding or prolapsing in the spinal canal, the surgical procedure is similar to that of open surgery by pulling the nerve root and dural sac
. As a result, the risks of nerve root damage and adhesion during MED are the same as those during open surgery.11,12 As regards PTED, it is a minimally invasive method for treating LDH via the lateral approach.
MRI images revealed a consistent collection of acute intradural hematoma inside the dural sac
approximately 8 cm long between the L1-L3 vertebral bodies, which caused a significant compression of the dural sac
fibers (Figure 2.
There is also an abrupt wedge-shaped terminus of the cord, which lies opposite T12 and an abnormal course of the cauda equina with separation of the anterior and posterior nerve roots, forming the "double bundle shape." The dural sac
is abnormally highly placed, ending at L5.
In Hirayama disease, chronic ischemic changes involving the anterior horns of the cord from C5-T1 level occur due to repeated cord flexion within a tight dural sac
. (3) Disproportionate growth of the vertebral column in comparison with the spinal cord is also an etiological factor.
Imaging features were retrospectively analysed according to MR features of cervical cord appearance, attachment of dural sac
and contrast enhancement pattern.
Magnetic resonance imaging (MRI) of the lumbar spine and sacrum revealed a solid expansive lesion on L2 topography, with an extensive epidural soft tissue component, infiltrating the bone marrow and determining compression of the dural sac
. At that time, a core biopsy was performed, which revealed a lesion consistent with a grade 2 chordoma with positive immunostaining for pan-cytokeratin (AE1/AE3), S-100 protein, epithelial membrane antigen (EMA), and Ki-67 index of 20%.
The lamina was thinned out using a burr to avoid further insult to the dural sac
, and then using a Kerrison ronguer, laminectomy was completed all around the lesion under microscopic guidance (Figure 4).
Before the wood was removed, the dural sac
was mildly compressed above the level continuously, to prevent CSF from filling our surgical field.
Once the dural sac
was incised, the MEPs' amplitude suddenly dropped significantly because of the instant release of high-intradural pressure.
Due to the special anatomical structure and functional characteristics of the upper lumbar spine, such as the narrow spinal space and the smaller range of motion, the dural sac
and nerve structure in the spinal canal of the upper lumbar are more likely to be compressed, which is more likely to manifest as multiple neurological disorders rather than being limited to the involvement of a certain nerve .