8.Tarlov Cysts, Lumbarized Sacral Segment (S1), Complex Bilateral Entrapment Syndrome
Tarlov cysts as perineural cysts [meningeal] that proliferate along sacral nerve roots. Their outer walls are vascular connective tissue, and their inner wall is lined with flattened arachnoid tissue; thin and fibrous; rupture prone; nerve fibers have appearance of dental floss and sometimes contain ganglion cells; no specific alignment; can contain CSF.
This case has a segmental variant. The first sacral segment is partially lumbarized and labeled as S1.
Tarlov cysts on left (4.0mm) / right (5.0mm) S2 spinal nerves.
Bilobed Tarlov cysts on left (5.0mm) / right (5.0mm) S3 spinal nerves.
Coccyx distortion is slightly rotated to the right, while low sacrum rotates slightly to face toward left side.
Significant hyperintensity per neurographic image.
Suggestive of an impar ganglion syndrome in light of the accompanying symptoms.
Segmental variant described another way by another doctor; transitional S1 vertebral body; 6 lumbar type vertebral bodies; the vertebral body at the lumbrosacral junction likely represents a partially lumbarized S1; this vertebral body articulates with the left sacrum.
About instructive and inducement possibilities for proposed "lumbarization."
Lumbarization is an anomaly in the spine. It is defined by the nonfusion of the first and second segments of the sacrum. The lumbar spine subsequently appears to have six vertebrae or segments, not five. This sixth lumbar vertebrae is known as a transitional vertebrae. Conversely the sacrum appears to have only four segments instead of its designated five segments.
The Instructions:
Sacral vertebrae develop in 1st and 2nd month of embryonic development. The 5 sacral vertebrae are separate early on, but they start to fuse during adolescence and early adulthood. They form into a single bone by age 30. The first 3 sacral vertebrae form the wide lateral wings called alae and connect to the pelvis.
Somitogenesis involves human segmentation clock (somite segmentation); segmental organization of the vertebral column established in embryogenesis; pairs of somites rhythmically produced - presomitic mesoderm; an oscillator; orthologue of cyclic genes...
mesoderm>notochord>somites
Embryogenesis vertebral column derives from somites as primary segments of the embryonic paraxial mesoderm, and somites are epithelial spheres (ventral cells) that undergo epithelial mesenchymal transition (EMT).
Two primary ossification centers coalesce after birth; separated from primary ossification of vertebral centrum cartilaginous region (dentocentral synchondrosis); synchondrosis is slow growing bipolar physis that involves cartilage; the cartilage structure is continous throughout the body; it is not until 8-10 years old that secondary ossification center (ossiculum terminale) developes at proximal dens epiphysis; fusion occurs between 10-13 years.
The Fusing:
Postnatal maturation of the sacrum and coccyx: MR imaging, helical CT, and conventional radiography:
We were able to determine the time at and manner in which intersegmental fusion occurs between adjacent sacral segments. The rudimentary intervertebral discs have been described to fuse in a cephalad direction between the ages of 18 and 25 years. This age range was confirmed at S1-S2 and S2-S3, but we found the lower two sacral rudimentary discs typically fuse earlier, before the age of 15. Fusion between the coccygeal segments and S5 was highly variable, occurring between the ages of 15 and 28. The timing of intersegmental fusion of the lateral elements (CPs and transverse processes) of the sacrum has not been described to our knowledge. Fusion of the lateral elements occurred over a broad age range but usually was completed by the age of 18, except between S5 and the first coccygeal vertebra, at which fusion may occur as late as the age of 27...
In conclusion, the sacrum is formed by a complex process of fusion of 58-60 primary and secondary ossification centers, which is not fully complete until the age of 30. The coccyx is formed by as many as eight ossification centers; however, the number of coccygeal segments that develop ranges from one to four. The maturation of the sacrum and coccyx may be asymmetric from side to side in terms of growth plate fusion and appearance of epiphyseal centers.
Fusion is something that transpires into adulthood, so it isn't really right to say this condition is absolutely congenital. Errant instructive process could have been acquired postnatally, induced.
More about this case's pain syndrome:
Per the neurography MRI: S2 and S3 spinal nerves demonstrate irritative changes in traversing the piriformis muscle bilaterally. At the level of the ischial spine on both sides there is an increased caliber of the pudendal nerve as well as associated venous structures as elements cross the level of the sacrospinous ligament at the ischial spine. On the medial aspect of the obturator internal muscle vein dilation is appreciated as well as persisting pudendal irritative changes. The vein dilation on the medial aspect of the obturator internus muscle is suggestive for obturator internus muscle spasm, which associates with pudendal irritation syndrome in light of pudendal nerve position on the medial aspect of the obturator interns muscle.
The irritation of S2 and S3 spinal nerves traverse the piriformis muscle and are antecedent along with S4 spinal nerves which are antecedent to the pudendal and obturator internus nerves downstream as well as the coccygeous...
In process.