Clinical analysis of thoracic ossified ligamentum flavum without ventral compressive lesion.
The aim of this study was to analyze the clinical characteristics of thoracic ossified ligamentum flavum (OLF) and to elucidate prognostic factors as well as effective surgical treatment modality. The authors analyzed 106 thoracic OLF cases retrospectively from January 1999 to December 2008. The operative (n = 40) and the non-operative group (n = 66) were diagnosed by magnetic resonance imaging (MRI) and/or computed tomography (CT) imaging. We excluded cases exhibiting ventral compressive lesions causing subarachnoid space effacement in thoracic vertebrae as well as those with a coexisting cervical compressive myelopathy. Those in the operative group were treated with decompressive laminectomy as well as resection of OLF. The preoperative neurologic status and postoperative outcomes of patients, as indicated by their modified Japanese Orthopedic Association (mJOA) scores and recovery rate (RR), Modic changes, the axial (fused or non-fused) and sagittal (omega or beak) configurations of OLF, and the ratios of the cross-sectional area (CSA) and anteroposterior diameter (APD) of the most compressed level were studied. The most commonly affected segment was the T10-11 vertebral body level (n = 49, 27.1%) and the least affected segment was the T7-8 level (n = 1, 0.6%). The ratios of the CSA in non-fused and fused types were 77.3 and 59.3% (p < 0.001). When Modic changes were present with OLF, initial mJOA score was found to be significantly lower than those without Modic change (7.62 vs. 9.09, p = 0.033). Neurological status improved after decompressive laminectomy without fusion (preoperative vs. last mJOA; 7.1 ± 2.01 vs. 8.57 ± 1.91, p < 0.001). However, one patient exhibited transient deterioration of her neurological status after surgery. In the axial configuration, fused-type OLF revealed a significant risk for a decreased postoperative mJOA score (0-7, severe and moderate) (Odds ratio: 5.54, χ (2) = 4.41, p = 0.036, 95% CI: 1.014-30.256). The results indicated that the new categorization of axial-type of OLF is a helpful predictor of postoperative patient outcome and fused type was related with poor prognosis. In OLF cases free from ventral lesions compressing the spinal cord, decompressive laminectomy is enough for successful surgical outcome. Therefore, early surgical treatment will be considered in cases with fused-type OLF compressing spinal cord even though they do not have myelopathic symptoms.
Yoon
Sang Hoon
SH
Department of Neurosurgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam-si, Gyeonggi-do, South Korea.
Kim
Wook Ha
WH
Chung
Sang-Bong
SB
Jin
Yong Jun
YJ
Park
Kun Woo
KW
Lee
Joon Woo
JW
Chung
Sang-Ki
SK
Kim
Ki-Jeong
KJ
Yeom
Jin S
JS
Jahng
Tae-Ahn
TA
Chung
Chun Kee
CK
Kang
Heung Sik
HS
Kim
Hyun-Jib
HJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007796:Laminectomy; D017843:Ligamentum Flavum / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D011859:Radiography; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome