Delayed-onset radiculopathy caused by a retropulsed bone fragment after percutaneous kyphoplasty: report of four cases and literature review

BACKGROUND: Vertebral compression fractures caused by osteoporosis are common in elderly patients and are often encountered by clinical physicians. Percutaneous balloon kyphoplasty (PKP) is widely accepted as a minimally invasive procedure for effectively relieving pain and correcting deformities, but complications may occur. Radiculopathy with a delayed onset caused by a retropulsed bone fragment has not been adequately described in the literature. Thus, this article presents a case report of four cases of retropulsed bone fragment-related radiculopathy after PKP. CASE PRESENTATION: In this article, we reported that four out of 251 patients developed radiculopathy after PKP between January 2012 and January 2019 despite experiencing substantial improvements in back pain. All patients with radiculopathy were female and diagnosed with osteoporosis, and their ages ranged from 68 to 89 years. Radiculopathy occurred from 2 to 16 weeks after PKP. All four patients underwent another operation (posterior decompression and instrumentation). Three patients recovered completely, and one died of postoperative intracranial haemorrhage. A detailed imaging study with pre- and postoperative magnetic resonance imaging (MRI) revealed that retropulsed bone fragments that impinged on the corresponding root after PKP were responsible for this complication, and all four patients developed a disrupted posterior vertebral rim preoperatively. No leakage of cement or pedicle track violations were observed. CONCLUSION: Although PKP is a safe and effective treatment for painful osteoporotic vertebral compression fractures, a risk of catastrophic neurological injury remains. Radiculopathy with delayed onset caused by a retropulsed bone fragment after kyphoplasty is rare and challenging to treat, and the integrity of the posterior vertebral cortex should be carefully evaluated preoperatively to prevent this complication.