Posterior approach with augmented pedicle screw instrumentation in the osteoporotic vertebral fracture: middle to long term follow-up

English Keywords:Osteoporotic vertebral fracture  Posterior approach  Instrumentation  Augmented pedicle screw

English Abstract:

  【Abstract】 Objectives: To analyze the safety and effects of augmented pedicle screw instrumentation via posterior approach in treating the osteoporotic vertebral fracture with a medium to long term follow-up. Methods: From January 2008 to December 2015, 41 patients(37 females, 4 males) were enrolled with an average age of 72±5.8 years old(66-88y), whose mean disease course was 6.75±3.20 months(8h-27m) and BMD with T score at -3.80±1.12SD(-2.9 to -5.4SD). There was a total of 52 index vertebrae, among which 33 with intravertebral pseudo joints(63.46%), 3 with malunion(5.77%) and 12 with severe collapse(23.08%). The individual maximum collapse rate was from 32% to 95%[mean at(72.0±15.2)%], and the percentage of bony fragments occupying the spinal canal was 22.1% to 71.4%[mean at (42.3±11.4)%]. The pre-op neurological statuses on ASIA were grade C in 8 cases, grade D in 10 cases, and grade E in 23 cases. All received augmented pedicle screw instrumentation combined with individual index vertebral augmentation, decompression or osteotomy via posterior approach. The visual analogue scale(VAS) and Oswestry disability index(ODI) before operation, at 1 week post-op and final follow-up were recorded, and the kyphotic angles before operation, at 1 week, 2 years post-op and final follow-up were also measured, as well as the related complications. Results: 35 patients were followed for 24 to 108 months, with an average of 38.9±29.0 months. 2 patients were dead for surgery-unrelated reasons and the rest 4 patients were lost at final follow-up. The VAS scores decreased significantly from pre-op 8.07±1.52 to 3.26±2.40 at 1 week post-op and 2.66±1.49 at the last follow-up, and ODI decreased from pre-op (72.30±11.80)% to (46.70±16.28)% at 1 week post-op and (35.89±11.90)% at final follow-up. Kyphotic angles were significantly corrected from pre-op 26.73°±15.22° to 7.84°±9.18° at 1 week post-op, 11.18°±9.57° at 2 years post-op and 11.43°±1.93° at finalt follow-up(P<0.05). The three variables improved significantly postoperatively(P<0.05), and in addition, the disability function improved at final follow-up compared to that at 1 week post-op(P<0.05), while VAS and kyphotic angle showed equivalent change between the postoperative intervals(P>0.05). 11 patients got recovery from the neurological deficit at finalt follow-up, 3 cases from grade C to D, 5 cases from grade C to E, 3 cases from grade D to E and the rest 7 cases remained at grade D. Besides, 8 cases got rid of pre-op leg radicular pain and numbness. As for the complications, asymptomic cement leakage was observed in 13 cases(31.71%) and 10 new vertebral fractures(24.39%, 5 patients) occurred including 5 adjacent segments(12.20%, 5 patients). No cement migration or screw loose was detected. Conclusions: The patients with osteoporotic vertebral fractures acquired pain relief, function improvement and kyphotic deformity correction after the posterior approach with augmented pedicle screw instrumentation without fixation failure at the middle to long term follow-up.