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Low transverse sacral fractures are rare, with only two published reports regarding their surgery. The complication associated with surgery for sacral fractures is the prominence of implants. In addition, screw fixation below S3 is impractical. We performed posterior sacral fixation using S2 alar iliac (S2AI) screws and sacral sublaminar wires for low transverse sacral fractures. Case 1 was 65-year-old male with an S2-3 transverse sacral fracture. We performed laminectomy (S2-3) and passed ultrahigh molecular weight polyethylene (UHMWPE) cables from laminectomy area to the third posterior sacral foramina. We inserted S2AI screws and connected rods. We also tightened the UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. Case 2 was a 42-year-old female with an S2 transverse sacral fracture. We performed laminectomy (S1–3) and passed UHMWPE cables from laminectomy area to the third and fourth posterior sacral foramina. We inserted S1 pedicular screws and S2AI screws and connected rods. We also tightened UHMWPE cables. The implants did not protrude into skin. One year after surgery, the sacral fracture healed without any displacement. We consider sacral sublaminar wires to be useful bone anchors in lower sacrum.

While 22 articles have reported on sacral stress fractures, it is a rare injury and its etiology is not well known. We present the case of a 16-year-old male who presented with low back pain in 2015. He was a high school soccer player with a previous history of a bilateral L5 lumbar spondylolysis in 2014. The patient refrained from soccer and wore a brace for six months. Two months after restarting soccer, he again complained of low back pain. After 1 year, a lumbar spine computed tomography revealed the bone union of the spondylolysis. At his first visit to our hospital, his general and neurological conditions were normal and laboratory data were within the normal range. Sacral coronal magnetic resonance imaging (MRI) of the left sacral ala revealed an oblique lineal signal void surrounding bone marrow edema. Based on his symptoms, sports history, and MRI, he was diagnosed with a sacral stress fracture. He again refrained from soccer; his low back pain soon improved, and, after 1 year, the abnormal signal change had disappeared on sacral MRI. Recurrent low back pain case caused by a sacral stress fracture occurring after the bone union of lumbar spondylolysis is uncommon.

Intradural extra-arachnoid lumbar disc herniation is a rare disease. Few MRI findings have been reported. We experienced an intradural extra-arachnoid lumbar disc herniation. We reviewed the preoperative MRI findings. Lumbar spine T2-weighted sagittal MRI showed that one line of the ventral dura was divided into two by a disc herniation. We speculated that the two lines comprised the dura and arachnoid and that a disc herniation existed between them. We believe that division of the ventral dural line on T2-weighted sagittal images is a characteristic finding of intradural extra-arachnoid lumbar disc herniation. The division of ventral dural line seemed to be a “Y,” and, thus, we called it the “Y sign.” The “Y sign” may be useful for diagnosing intradural extra-arachnoid lumbar disc herniation.

A 76-year-old man presented with a Denis Zone III sacral fracture after a traffic accident. He also developed urinary retention and perineal numbness. The patient was diagnosed with neurogenic bladder dysfunction caused by the sacral fracture. A computed tomogram (CT) revealed that third sacral lamina was fractured and displaced into the spinal canal, but vertebral body did not displace. The fracture lines began at the center of lamina and extended bilateraly. The fracture pattern was unique. The sacrum was osteoporosis, and this fracture may be based on osteoporosis. We performed laminectomy to decompress sacral nerve roots. One month after surgery, the patient was able to urinate. Three months after surgery, his bladder function recovered normally. One year after surgery, he returned to a normal daily life and had no complaints regarding urination. One-year postoperative CT showed the decompressed third sacrum without displacement.

A case of ossification of transverse ligament of atlas (TLA) is reported. A 76-year-old female suffered from a transverse type myelopathy was successfully treated by posterior decompression. Dynamic lateral plain radiographs showed irreducible atlantoaxial subluxation (AAS). A computed tomogram revealed ossified mass compatible to ossification of TLA. Coalition of the atlantooccipital joints and osteoarthritis of the atlantoaxial joints with degenerated dens was also revealed. Magnetic resonance imaging showed compressed spinal cord at C1 level by the ossification of TLA and AAS. We suggest a mechanism of ossification of TLA as follows: hypertrophied dens and stress to the atlantoaxial joints caused by coalition of atlantooccipital joints could make forward shift of atlas leading to irreducible AAS, and continuous tension given to TLA from irreducible AAS would result in hypertrophied and ossification of TLA.

Spontaneous thoracic spinal subarachnoid hemorrhage is rare, and thus no useful radiological findings for preoperative diagnosis have been reported. We experienced a patient with spontaneous thoracic spinal subarachnoid hemorrhage. A 37-year-old female presented with sudden-onset paraplegia and numbness in the trunk and bilateral lower extremities. The patient had no past history of trauma, lumbar puncture and bleeding disorder. T2-weighted sagittal magnetic resonance imaging (MRI) of the cervical and thoracic spines showed a mass occupied in the ventral space of spinal cord that was dorsally shifted. The mass extended from C6 to Th6 levels, with its largest size at Th2 level. Thoracic spine T2-weighted sagittal and axial MRI showed that the mass compressed spinal cord and was located in the intradural space. There was no spinal cord tumor and no spinal vascular malformation around the mass. Brain computed tomography (CT) showed a high-density area in the subarachnoid space, indicating the possibility of subarachnoid hemorrhage. Brain MRI showed no ruptured aneurysm. The patient was diagnosed as a spontaneous thoracic spinal subarachnoid hemorrhage and emergency surgery was selected. We performed right-side hemilaminectomy at Th1-Th6 and opened dura mater and arachnoid membrane. Hematoma was found in the ventral space of spinal cord and was removed. One year after surgery, numbness in the trunk and bilateral lower extremities had disappeared but paraplegia remained unchanged. Thoracic spine T2-weighted MRI confirmed no hematoma but showed a newly formed intradural cyst. Preoperative combination of brain CT and thoracic MRI is useful to diagnose thoracic spinal subarachnoid hemorrhage. [ABSTRACT FROM AUTHOR]