Is It Real False Negative Finding in Motor Evoked Potential Monitoring during Corrective Surgery of Ankylosing Spondylitis? A Case Report

We performed L1 posterior vertebral columnar resection and posterior correction for Andersson's lesion and thoracolumbar kyphosis in an ankylosing spondylitis patient during motor evoked potential (MEP) monitoring. We checked MEP intra-operatively, whenever a dangerous procedure for neural elements was performed, and no abnormal findings were seen during surgery. After the operation, we examined neurologic function in the recovery room; the patient showed a progressive neurologic deficit and no response to MEP. After emergency neural exploration and decompression surgery, the neurologic deficit was recovered. We questioned whether to acknowledge the results of this case as a false negative. We think the possible reason for this result may be delayed development of paralysis. So, we recommend that MEP monitoring should be performed not only after important operative steps but also after all steps, including skin suturing, for final confirmation.

Association of Estrogen Receptor 2(ESR 2) Gene Polymorphisms with Ossification of the Posterior Longitudinal Ligament of the Spine

STUDY DESIGN: Genetic screening of the estrogen receptor 2 (ESR2) genes in patients with ossification of the posterior longitudinal ligament (OPLL). OBJECTIVE: We studied the relationships between ESR2 gene polymorphisms and OPLL to understand the pathophysiology of OPLL. SUMMARY OF LITERATURE REVIEW: The OPLL has a strong genetic component. Several familial surveys and human leukocyte antigen (HLA) haplotype studies reveal that genetic background is an important component in the occurrence of OPLL and a large number of gene analysis studies were utilized to clarify the susceptible gene for OPLL, including COL11A2, BMP-2, TNF-alpha, NPPS, leptin receptor, transforming growth factor (TGF)-beta, Retinoic X receptor, ER, IL-1, PTH, and VDR have been performed. MATERIALS AND METHOD: Genomic deoxyribonucleic acid (DNA) samples obtained from 164 patients (93 men and 71 women) with OPLL and 219 control subjects, without the disease (105 men and 114 women) were amplified by polymerase chain reaction, and polymorphism genotypes were determined by the restriction endonuclease digestion. The distribution of genotypes was compared between the patients with the disease and the control subjects. RESULTS: The polymorphism of ESR2 [rs1256049, exon6, Val328Val, p=0.018, odd ratio (OR)=2.41, 95 confidence interval (CI)=1.15-5.02 in the recessive model] only showed statistically significant association between the control and the OPLL groups. The rest SNPs of ESR2 did not show any significant differences between the control and the OPLL groups. CONCLUSIONS: Estrogen receptor 2 (ESR2) gene polymorphisms (rs 1256049) was associated with OPLL. In future studies, we will perform target SNP chip between OPLL and candidate gene.