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Purpose Posterior decompression with instrumented fusion (PDF) is a suitable surgical treatment for K-line (−)-type cervical ossification of the posterior longitudinal ligament (OPLL). However, the adequate indications of PDF have not been clarified yet. The purpose of this study was to investigate the surgical results of PDF and perioperative factors that influence the surgical outcome, and to clarify the adequate indications of PDF. Methods Twenty-seven patients (21 men and 6 women, mean age: 61.4 years) who were diagnosed with a K-line (−)-type OPLL that was treated with PDF were included in this study. We evaluated these patients clinically and radiologically to investigate the outcomes of PDF and perioperative factors that influence improvements in the Japanese Orthopedic Association (JOA) score. Results The mean recovery rate of JOA score at the final follow-up examination was 53.3%. In the statistical analysis, the preoperative C2-C7 angle and the C2-C7 angle immediately postoperatively significantly predicted the surgical outcome. The C2-C7 angle immediately postoperatively was the only most important predictor. Using a receiver operating characteristic curve analysis, we found that the cutoff value of the C2-C7 angle immediately postoperatively for good outcomes (recovery rate of JOA score ≥50%) was −2.0°. Conclusions PDF for K-line (−)-type OPLL patients with preoperative lordotic alignment can be expected to have favorable outcomes, which is the adequate indication for PDF. Since the C2-C7 angle immediately postoperatively was the most important predictor, the physician should pay attention to maintain the cervical lordotic alignment to enhance the surgical outcomes in surgical planning.

In animal models of spinal cord injury (SCI), inducible NO (nitric oxide) synthase is expressed in the spinal cord immediately after sustaining SCI. Excessive NO production has cytotoxic effects and induces neuronal apoptosis, causing neural degeneration and neurodysfunction in the spinal cord. Little is known, however, about the relationship between NOx (NO metabolites: nitrite and nitrate) levels in the cerebrospinal fluid (CSF) and neurologic severity or recovery in clinical cases. The objective of the present study was to examine the correlation between CSF NOx levels and neurologic severity or recovery in SCI. Twenty-five patients with incomplete cervical cord injury (CCI) were examined. Eight cases were treated conservatively (non-operated group). Seventeen cases underwent surgical intervention (operated group). NOx levels in the CSF were measured using the Griess method. The severity of the neurologic impairment was assessed using Frankel’s classification and the American Spinal Injury Association motor score (ASIA MS). The degree of neurologic recovery was assessed using Frankel’s classification and the ASIA motor recovery percentage (MRP). There was no significant difference in the NOx levels between the CCI group (NOx levels: 5.9 ± 0.7 μM) and the 36 control subjects (1 volunteer and 35 patients without neurologic disorders, NOx levels: 4.9 ± 0.3 μM). There was no significant difference in NOx levels and MRP between the non-operated group and the operated group. The NOx levels in total SCI group were significantly correlated with the ASIA MS and MRP. There was a significant correlation between CSF NOx levels and neurologic severity or recovery in incomplete CCI.

We investigated the time course of changes in nitric oxide metabolite (NO2- plus NO3-: NOx) levels in the cerebrospinal fluid and the expression of local inducible nitric oxide synthase following cauda equina compression in rats. Cerebrospinal fluid NOx levels were significantly increased from 12 h to 3 days after compression, and decreased thereafter. Histologically, inducible nitric oxide synthase immunoreactivity was observed in macrophages that infiltrated the dura mater on days 1 and 3 after compression, but not in foamy macrophages in the parenchyma of the cauda equina observed afterwards. The pattern of NOx levels coincided with the appearance of inducible nitric oxide synthase labeled macrophages, indicating a critical role of these cells as the main synthesizers of NOx in the acute stage of cauda equina compression.

Halo application is a standard method for cervical immobilization. However, complications may occur in children because of their thin skull and immature bone. The authors report two cases of odontoid fracture in preschool children treated with a Minerva cast. Two 4-year-old children sustained displaced odontoid fractures in motor vehicle accidents. The fractures were immediately reduced and immobilized using a Minerva cast, followed by the application of a soft collar. By the 1-year follow-up, uneventful bone union had occurred, and the children were able to attend preschool with minimal or no neurologic deficits. The Minerva cast is a classic, inexpensive method of cervical immobilization and is still useful for this kind of fracture. Immediate reduction and immobilization with a Minerva cast is a viable option for displaced odontoid fractures in preschool children.