Experimental rat model for cervical compressive myelopathy

Previously, a rat model of chronic compressive myelopathy that uses a water-absorbing polymer inserted under a spinal lamina was reported. However, the best size and coefficient of expansion of the polymer sheet have not yet been established. The aim of the present study was to optimize these properties in an ideal rat model of cervical compressive myelopathy. Thirty rats were used in this study. A sheet of water-absorbing polymer was inserted under the cervical laminae. Rats were divided randomly into five experimental groups by the expansion rate (350 or 200%) and thickness (0.5 or 0.7 mm) and the control. After the surgery, the severity of paralysis was evaluated for 12 weeks. At 12 weeks after the surgery, cresyl violet staining was performed to assess the number of motor neurons in the anterior horn at the C4/C5 segment and Luxol Fast Blue staining was performed to assess demyelination in the corticospinal tract at the C7 segment. ‘Slow-progressive’ paralysis appeared at 4–8 weeks postoperatively in rat models using sheets with 200% expansion. By contrast, only temporary paralysis was observed in rat models using sheets with 350% expansion. A loss of motor neurons in the anterior horn was observed in all groups, except for the control. Demyelination in the corticospinal tract was observed in rat models using sheets with 200% expansion, but not rat models using sheets with 350% expansion. A polymer sheet that expands its volume by 200% is an ideal material for rat models of cervical compressive myelopathy

Exploration of Spinal Cord Aging–Related Proteins Using a Proteomics Approach

How aging affects the spinal cord at a molecular level is unclear. The aim of this study was to explore spinal cord aging–related proteins that may be involved in pathological mechanisms of age-related changes in the spinal cord. Spinal cords of 2-year-old and 8-week-old female Sprague-Dawley rats were dissected from the animals. Protein samples were subjected to 2-dimentional polyacrylamide gel electrophoresis followed by mass spectrometry. Screened proteins were further investigated with immunohistochemistry and Western blotting. Among the screened proteins, we selected α-crystallin B-subunit (αB-crystallin) and peripherin for further investigation because these proteins were previously reported to be related to central nervous system pathologies. Immunohistochemistry and Western blotting revealed significant upregulation of αB-crystallin and peripherin expression in aged rat spinal cord. Further exploration is needed to elucidate the precise mechanism and potential role of these upregulated proteins in spinal cord aging processes

Cervical restenosis caused by progressive ossification of the posterior longitudinal ligament in patients following laminoplasty: Two case reports

We report two cases of restenosis caused by the progression of thickness of ossification of the posterior longitudinal ligament (OPLL) seven and more years after laminoplasty, resulting in neurological deterioration needed for revision anterior decompressive surgeries. Neurological recovery after revision anterior excision of OPLL was poor. In both cases, the patients had progressive OPLL, with a non-ossified segment of the ossification foci, in common. After laminoplasty, they also both exhibited osseous fusion of the elevated laminae, but there was discontinuity at the interlaminar space at the peak level of OPLL. Discontinuity of the osseous fusion in the elevated laminae might cause mechanical stress increases at the non-ossified segment of the OPLL and could lead to the progression of OPLL. The present cases showed that long-term progression of OPLL can induce neurological deterioration even after sufficient posterior decompression by laminoplasty. Therefore, when considering risk factors that may be predictive of the progression of OPLL after laminoplasty, it is important to perform strict follow-up examination to check for progression to reduce the risk of myelopathy symptoms that are indicative of neurological deterioration

Communication about incisional hernia through an iliac crest bone harvest site after reoperative cervical anterior fusion

We report the case of an incisional hernia through the wound made for iliac bone harvest for re-operative cervical fusion surgery. A 50-year old woman underwent revision anterior cervical discectomy and fusion (ACDF) using a poly ether ether ketone cage and titanium alloy locking plate for adjacent segment disease after prior ACDF. As an autograft, iliac cancellous bone was again harvested from the left iliac crest, using the prior surgical scar. Although only cancellous bone from the medial side of the iliac bone was collected, leaving the iliac crest intact, she complained of a protrusion from the left lower abdomen, of which diagnosis was an incisional hernia through the iliac bone harvest site. Formation of an incisional hernia at the iliac bone harvest site is a possible complication after spine surgery. Care must be taken for oblique abdominal muscle repair around the iliac bone harvest site, particularly in re-operative cases. Keywords: Incisional hernia, Iliac crest, Bone graft, Spinal fusion surger