[The analysis of prognostic factors in patients with thoracic ossification of the ligamentum flavum and thoracic ossification of posterior longitudinal ligament by posterior decompression].

OBJECTIVE

To investigate the prognostic factors for patients with thoracic ossification of the ligamentum flavum (OLF) and thoracic ossification of posterior longitudinal ligament (OPLL).

METHODS

Clinical information of 83 patients suffering from thoracic OLF and OPLL was reviewed retrospectively from January 2006 to June 2010. The related factors such as gender, age, preoperative and postoperative Japanese Orthopedic Association (JOA) score, pathological segment, type of thoracic OPLL, degree of thoracic kyphosis, anteroposterior diameter of OPLL, range of circumferential decompression, cerebrospinal fluid leakage or not and dysfunction or not and carotid lumbar disorders or not were analyzed by Chi-square and Logistic regression.

RESULTS

All cases were classified into desirable group (58 cases) and undesirable group (25 cases) based on the postoperative JOA score improvement rate. Comparison of physical characteristics between two groups of age, preoperative JOA and the course of the disease had not statistically significant (P > 0.05). Two groups in pathological segment of thoracic OPLL (χ(2) = 6.290, P = 0.043), the ossification type of OPLL (χ(2) = 5.361, P = 0.021) and dysfunction or not in preoperative (χ(2) = 27.711, P = 0.000) had significant difference. Logistic regression analysis showed that the upper thoracic segments (P = 0.044), beak type ossification (P = 0.023) and with dysfunction in preoperative (P = 0.009) were risk factors. There were 24 patients (28.9%) with cerebrospinal fluid leakage, 3 patients with early postoperative deep infection and neurological deterioration of 2 cases in postoperative.

CONCLUSIONS

Patients with ossification on the upper section of thoracic have a better prognosis, but the beaked localized longitudinal ligament ossification in patients and associated with preoperative dysfunction show a poor prognosis, combined jumping segmental ossification and cervical or lumbar severe disorders are the influencing factor for poor prognosis.