Spinal Canal Flashcards
Spinal Canal
What are the three classifications of spinal canal tumors based on their location relative to the protective layers of the cord?
extradural,
intradural–extramedullary,
or intramedullary
Spinal Canal
How many pairs of spinal nerves are there?
31 pairs
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
Spinal Canal
Spinal cord anatomy
The gray matter is located in the periphery surrounding a central white matter.
TRUE or FALSE?
False.
Spinal Canal
Spinal cord anatomy
What horn of the gray matter controls the motor function
anterior horn
Spinal Canal
Spinal cord anatomy
What horn of the gray matter controls the autonomic functions
lateral horns
Spinal Canal
Spinal cord anatomy
What horn of the gray matter is involved with sensation
posterior horn
Spinal Canal
Spinal cord anatomy
the axons of the spinal cord are myelinated
TRUE or FALSE?
True
Spinal Canal
Spinal cord anatomy
What transmits muscle stretch and tone sensation from the extremities to the brain?
spinocerebellar tract
vibration
Spinal Canal
Spinal cord anatomy
What carries pain fibers to the brain?
lateral spinothalamic tract
heat and cold
Spinal Canal
Spinal cord anatomy
What transmits fine touch and positional sensation from the extremities to the brain
dorsal column
Spinal Canal
Spinal cord anatomy
At what level does the dural sac ends?
S2-3
Spinal Canal
Spinal cord anatomy
At what level does the dura ends?
coccyx
Spinal Canal
Spinal cord anatomy
At what level does the subarachnoid space sac ends?
S2-3 with the dural sac
Spinal Canal
Most of the primary spinal canal tumors are malignant
TRUE or FALSE?
False
Based on population data in the National Program of Cancer Registries (NPCR)
and Surveillance, Epidemiology, and End Results (SEER) programs from 2004
to 2007, 22% of primary spinal tumors are malignant and 78% nonmalignant
(62% benign and 16% with borderline behavior).
Spinal Canal
Most of the malignant spinal canal tumors occcur in males
TRUE or FALSE?
False
equally distributed.
Nonmalignant are more common in females.
Spinal Canal
What is the most common histology of spinal canal tumors?
Meningioma
followed by nerve sheath, ependymoma, and astrocytoma
Spinal Canal
What is the most common form of treatment failure of spinal canal tumors?
Local tumor progression
Spinal Canal
What is the most common presenting symptom of spinal canal tumors?
Pain
Spinal Canal
The incidence of leptomeningeal spread in patients with primary spinal cord glioma is low overall but is substantially more common with malignant tumors.
Of note, two recently recognized entities have significantly higher risk of leptomeningeal dissemination:
what are these entities?
glioblastoma with primitive neuronal component
and
diffuse leptomeningeal glioneuronal tumors (DLGT).
Spinal Canal
Differentiate the growth pattern of schwannoma and neurofibrorima in the spinal canal.
Neurofibromas typically encase involved nerve roots, whereas schwannomas commonly displace the nerve roots because of their assymetric growth.
NISD
Spinal Canal
Differentiate the schwannoma and neurofibrorima in the spinal canal in terms of genetic predisposition
neurofibroma (nf1)
schwannoma (nf2)
Spinal Canal
Prognostic Factors
In spinal cord astrocytomas, lower grade, younger, age, and surgical resection, and RT are predictors of better OS and cause-specific survival.
TRUE or FALSE?
false.
RT is predictor of worse CSS.
(Milano et al.)
Spinal Canal
Prognostic Factors
In spinal myxopapillary ependymoma,
older age, adjuvant RT, GTR are associated with improved LC and PFS.
TRUE or FALSE?
True
Weber et al.
Spinal Canal
Prognostic Factors
In the Mallinckrodt Institute of Radiology experience, Garcia reported that the primary tumor location was the most important prognostic feature.
What location is mostly associated with morbidity and worse outcomes?
cervical
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RT
What is the traditional field borders for spinal canal tumors
cc: two vertebral bodies above and below
laterally - tips of lateral process
Spinal Canal
RT
What is the CTV for low-grade spinal canal tumors
preop tumor volume + associated intratumoral cysts
0.5 to 1.5 cm margin.
uninvolved syrinx is not necessarily included
Spinal Canal
RT
What is the standard PTV for low-grade spinal canal tumors (no OBI)
0.5 cm
Spinal Canal
RT
What is the CTV margins for high-grade spinal canal tumors
at least 1.5 cm
Spinal Canal
RT
What is the CTV for myxopapillary ependymomas of the conus?
1.5 cm cephalad and caudad but not beyond the thecal sac.
Spinal Canal
RT
When do you include the entire thecal sac in the RT volumes?
cauda equina involvement
Spinal Canal
RT
Dose prescription
low-grade tumors
50.4 (1.8) Gy
Spinal Canal
RT
Dose prescription
high-grade tumors
54 (1.8) Gy
Spinal Canal
RT
Dose prescription
high-grade ependymomas and low-grade astrocytomas
50.4 to 54 Gy
Spinal Canal
RT
Dose prescription if CSI is needed
36 to 45 Gy CSI with boost to gross 50.4 to 54 Gy
Spinal Canal
RT
early vs. late myelitis
L’Hermitte’s sign
early
Spinal Canal
RT
Latency period of chronic myelopathy
13 to 29 months
Spinal Canal
RT
Chronic myelopathy has a bimodal peak.
This peak corresponds to microvascular injury
late peak
Spinal Canal
RT
Chronic myelopathy has a bimodal peak.
This peak corresponds to white matter injury and demyelination
early peak
Spinal Canal
RT
What is the historical maximum tolerance dose of the spinal cord?
45 to 50 Gy
Spinal Canal
RT
According to QUANTEC, a dose of ___ Gy is associated with 0.2% rate of myelopathy
if given using 1.8 to 2 Gy conventional fractionation
50 Gy
Spinal Canal
RT
According to QUANTEC, a dose of ___ Gy is associated with 50% rate of myelopathy
if given using 1.8 to 2 Gy conventional fractionation
69 Gy
Spinal Canal
RT
What situations are associated with lower spinal cord tolerance?
children
patients receiving neurotoxic chemotherapy
Spinal Canal
RT
Bonus:
What is the Gd variant used to better delineate spinal canal tumors on MRI
Gd - DTPA
diethylene-triamine pentaacetic acid
