Effects of different pedicle screw insertion depths on sagittal balance of lumbar degenerative spondylolisthesis, a retrospective comparative study.

BACKGROUND: Few reports to date have evaluated the effects of different pedicle screw insertion depths on sagittal balance and prognosis after posterior lumbar interbody and fusion (PLIF) in patients with lumbar degenerative spondylolisthesis (LDS). METHODS: A total of 88 patients with single-level PLIF for LDS from January 2018 to December 2019 were enrolled. Long screw group (Group L): 52 patients underwent long pedicle screw fixation (the leading edge of the screw exceeded 80% of the anteroposterior diameter of vertebral body). Short screw group (Group S): 36 patients underwent short pedicle screw fixation (the leading edge of the screw was less than 60% of the anteroposterior diameter of vertebral body). Local deformity parameters of spondylolisthesis including slip degree (SD) and segment lordosis (SL), spino-pelvic sagittal plane parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL), Oswestry Disability Index (ODI), and Visual Analog Scale (VAS) for back pain of both groups were compared. Postoperative complications, including vertebral fusion rate and screw loosening rate, were recorded. RESULTS: Except that PI in Group S at the final follow-up was not statistically different from the preoperative value (P > 0.05), other parameters were significantly improved compared with preoperative values one month after surgery and at the final follow-up (P < 0.05). There was no significant difference in parameters between Group L and Group S before and one month after surgery (P > 0.05). At the final follow-up, SD, SL, LL, PT and PI-LL differed significantly between the two groups (P < 0.05). Compared with the preoperative results, ODI and VAS in both groups decreased significantly one month after surgery and at the final follow-up (P < 0.05). Significant differences of ODI and VAS were found between the two groups at the final follow-up (P < 0.05). Postoperative complications were not statistically significant between the two groups (P > 0.05). CONCLUSIONS: PLIF can significantly improve the prognosis of patients with LDS. In terms of outcomes with an average follow-up time of 2 years, the deeper the screw depth is within the safe range, the better the spino-pelvic sagittal balance may be restored and the better the quality of life may be.

Chondroblastic osteosarcoma secondary to fibrosarcoma: A case report and literature review.

Osteosarcoma, which is most common in non-blood systemic tumors, accounts for 20% of primary bone malignancies. Primary osteosarcoma usually occurs in young individuals aged 10-20 years, while secondary osteosarcoma is more common in the elderly. It had been reported that secondary osteosarcoma may be associated with osteofibrous dysplasia, bone infarction, chondrosarcoma or osteogenesis imperfecta. However, osteosarcoma secondary to fibrosarcoma has rarely been reported. The current study presents the rare case of a female with chondroblastic osteosarcoma secondary to fibrosarcoma. The patient was relatively young and suffered from more than one type of cancer. The course of the disease lasted for >20 years. This case study provides general knowledge of osteosarcoma, and discusses its clinical presentation, diagnosis, treatment and prognosis.