ABSTRACT
Background: Currently, change in pelvic incidence (PI) in patients after spinal surgery have not been associated with clear clinical symptoms. This study sought to compare changes in the sagittal parameters of different patients before and after thoracolumbar spine surgery, the relationship between PI change and sacroiliac joint pain (SIJP) after surgery was clarified, and the correlation between PI change and sacroiliac joint (SIJ) activity was verified. Methods: This study retrospectively analyzed the data of patients who underwent thoracolumbar fusion at Sun Yat-sen Memorial Hospital from January 2019 to June 2021. The spinal and pelvic parameters [including pelvic tilt (PT), sacral slope (SS), PI, lumbar lordosis (LL) angle, etc.] of 409 patients with standard standing lateral radiographs before and after surgery were compared and analyzed. Postoperative follow-up of all patients with standardized SIJP assessment. The incidence of postoperative SIJP, and its correlation with sagittal parameters of the spine and pelvis, surgical methods, and the basic characteristics of patients were analyzed. The Chi-square test was used for categorical variables, the independent-sample t-test was used for generally conformed normally distributed continuous variables. Risk factors associated with the development of SIJP were analyzed using logistics regression. Correlations among SS, PI, and the 4 other sagittal parameters were analyzed using the Pearson correlation coefficient (r). Results: Postoperative PI changes tended to be larger in the lowest instrumented vertebra (LIV) (L4 and above: 1.63°; L5: 2.43°; S1: 3.83°; P<0.05) and longer fixed segment. The risk factors for SIJP included a PI >4° [odds ratio (OR) =13.051; P<0.001], LIV S1 (OR =3.378; P=0.023), and fixed total segment ≥3 (OR =2.632; P=0.038). ∆PI was significantly correlated with ∆SS in patients with non-S1 distal fixation vertebrae (R2=0.388; P<0.01), but no such correlation was found in patients with S1 distal fixation vertebrate. Conclusions: Changes in PI values after thoracolumbar spine surgery can correctly reflect the motion state of the SIJ. Excessive changes in PI (>4°) are similar to the mechanism of distal junctional kyphosis (DJK), while such changes make patients prone to SIJP following lumbar spine surgery.
ABSTRACT
Chondroitinase has been used as an important tool in the study of the structure, function and distribution of glycosaminoglycans for many years. Recently, the enzyme has been reported to be a potential enzyme for chemonucleolysis, an established treatment for intervertebral disc protrasion. In this paper, a chondroitinase had been purified from the culture supernatant of Aeromonas sobria YH311 using a simple purification procedure of ammonium sulfate precipitation, QAE-Sephadex A50 ion exchange chromatography and Sephadex G-150 gel filtration. The immobilization of purified chondroitinase using sodium alginate or cellulose as carriers has also been studied. The chondroitinase obtained from Aeromonas sobria YH311 was purified 55-fold to 95.3% pure, the specific activity of the purified enzyme was 31.86u/mg and the yield was 37%. The molecular weight of chondroitinase from Aeromonas sobria YH311 was determined by SDS-PAGE to be 80kD, which was almost the same as those chondroitinase AC from Arthrobacter aurescens, Aeromonas liquefaciens and Flavobacterium heparinum. But its isoelectric point was 4.3 - 4.6, which was far lower than the microbial chondroitinase AC. After the immobilization on sodium alginate or cellulose, the properties of chondroitinase changed greatly. The optimum temperature and pH of the free enzyme were 50 degrees C and 7.0 respectively, and about 10% activity remained after heat treatment at 80 degrees C for 20 minutes, and 47% activity remained after two weeks storage at 4 degrees C. The chondroitinase immobilized on sodium alginate had the optimum temperature and pH of 40 degrees C and 7.0 respectively, about 50% activity remained after 80 degrees C heat treatment for 120 minutes and 50% remained after 30 days storage at 4 degrees C. The chondroitinase immobilized on cellulose had the optimum temperature and pH of 70 degrees C and 6.0 respectively, and more than 70% activity remained after heat treatment at 80 degrees C and 30 days storage at 4 degrees C. The yield of the immobilization was very low, with 18.56% for alginate and 18.86% for cellulose.
