Abstract:

Objective： To describe the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis. Methods: Observation group included 14 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws from November 2014 to July 2015, control group included 12 cases of degenerative lumbar diseases with osteoporosis received polymethylmethacrylate augmentation with traditional pedicle screws.The operation time, blood loss, number of pedicle screws and number of augmented pedicle screws in the two groups were compared. The bone cement leakage and pulmonary bone cement embolism in the two groups were also compared. The fusion rate and pedicle screws loosening by lumbar X ray and dynamic X ray were evaluated. The clinical results were assessed by visual analog scale (VAS) of pain on lumbar and lower limbers, lumbar Japanese Orthopaedic Association scores (JOA), Prolo functional scores and Oswestry disability (ODI) scores. Results: Differences of operation time and blood loss in the two groups were not statistically significant. The average number of pedicle screws was 9.9±4.7 and the average number of augmented pedicle screws was 5.9±2.6 in observation group while the average number of pedicle screws was 7.1±2.8 and the average number of augmented pedicle screws was 3.0±1.9 in control group. The ratio of augmented pedicle screws was higher in observation group than in control group （0.69±0.30 vs.0.47±0.30，P<0.05）. The bone cement leakage rate was lower in observation group than in control group (5/83 vs. 12/42, P<0.01). All the cases in observation group were without leakage to the interspinal canal while one case in control group suffered from bone cement leakage to the interspinal canal with augmentation of 3 pedicle screws. The follow up period was (10.6±2.3) months in observation group and (36.5±7.2) months in control group. In final follow up, no case with nonfusion or pedicle screws loosening was found in both groups. Lumbar VAS, lower limbers VAS, lumbar JOA scores, Prolo functional scores and ODI scores were all better than pre-operation (P<0.01). Conclusion: Polyme-thylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws for the treatment of degenerative lumbar diseases with osteoporosis was effective, with simple working processes and lower risk of bone cement leakage. The short-term clinical result was good.

Key words: Cannulated pedicle screws, Bone cement, Osteoporosis, Degenerative lumbar disease