Is there a risk of further displacement of the fractured fragment into the spinal canal in osteoporotic vertebral burst fractures after unilateral PKP? A prospective study

Abstract

Background context: The optimal treatment for osteoporotic vertebral burst fracture (OVBF) without neurological symptoms is still a matter of debate.

Purpose: To evaluate the safety and efficacy of percutaneous kyphoplasty (PKP) for OVBF.

Study design: The study is a prospective study and is registered in the China Clinical Trials Registry with the registration number ChiCTR-OOC-17013227.

Patient sample: The study involved 119 patients with 137 fractured vertebrae who underwent unilateral PKP for OVBF.

Outcome measures: The measurements were carried out independently by two physicians and measured with picture archiving and communication system (PACS) and ImageJ software (National Institutes of Health, Bethesda, MD, USA).

Methods: The change in the spinal canal area and posterior wall protrusions (PWP) were measured before and after surgery via three-dimensional computed tomographic imaging (CT). Preoperative, postoperative, and final follow-up standing X-rays were used to measure the height of the anterior wall (HAW), height of the posterior wall (HPW), and local kyphotic angle (LKA). Additionally, visual analogue scale (VAS) and the Oswestry Disability Index (ODI) were also determined.

Results: Among the 137 vertebrae assessed, 79 exhibited an increased postoperative canal area, while 57 showed a decrease, with mean values of 8.28±6.871 mm² and -9.04±5.991 mm², respectively. Notably, no significant change in postoperative canal area was identified on the entire dataset (p>.01). There was a significant decrease between median preoperative (3.9 [IQ1-IQ3=3.3-4.8] mm) and postoperative (3.7 [IQ1-IQ3=3.0-4.4] mm) PWP (p<.01). Preoperative and postoperative HAW measurements were 19.4±6.1 mm and 23.2±5.2 mm, respectively (p<.01). However, at the final follow-up, the HAW was lower than the postoperative value. The HPW was also significantly improved after surgery (p<.01), but at the final follow-up, it was significantly decreased compared with the postoperative measurement. Following surgery, KA was significantly corrected (p<.01); however, at the final follow-up, relapse was detected (average KA: 18.4±10.3 degrees). At the final follow-up, both VAS and ODI were significantly improved compared with the preoperative period (p<.01). As for complications, 50 patients experienced cement leakage, and 16 patients experienced vertebral refracture. All patients did not develop neurological symptoms during the follow-up.

Conclusions: OVBF without neurological deficits showed significant improvement in symptoms during the postoperative period after PKP. There was no notable alteration in the spinal canal area, but a significant decrease in PWP was observed. Consequently, we posit that PKP stands as a secure and efficacious surgical intervention for treating OVBF cases devoid of neurological symptoms.

Keywords: Burst fracture; Kyphoplasty; Osteoporosis; Posterior wall protrusions; Spinal canal area.