Outcomes of the use of cement-augmented cannulated pedicle screws in lumbar spinal fusion

Abstract

Background context: There are few studies of the radio-clinical outcomes of cement-augmented cannulated pedicle screw (CPS) fixation in osteoporotic patients.

Purpose: To compare the radiological and clinical outcomes between groups receiving cement-augmented CPS and solid pedicle screws (SPS) in lumbar fusion surgery.

Study design/setting: Retrospective comparative study PATIENT SAMPLE: A total of 187 patients who underwent lumbar fusion surgery for degenerative spinal stenosis or spondylolisthesis from 2014 to 2019.

Outcome measures: Radiological evaluation included screw failure, cage failure, rod breakage, and fusion grade at postoperative 6 months and 1 year. Pre- and postoperative visual analog scales for back pain (VAS-BP), leg pain (VAS-LP), Korean Oswestry disability index (K-ODI), and postoperative complications were also compared.

Methods: Outcomes of patients with high risk factors for implant failure [old age, osteoporosis, autoimmune disease or chronic kidney disease (CKD)] who underwent open transforaminal lumbar interbody fusion with cement-augmented CPS fixation (Group C, n=55) or SPS fixation (Group S, n=132) were compared.

Results: 324 pedicle screws in Group C and 775 pedicle screws in Group S were analyzed. Group C had a significantly higher average age and lower T-score, and included more patients with autoimmune disease and CKD than group S (all p<.05). Clear zones, screw migration and loss of correction were significantly less frequent in Group C (all p<.05). Thirteen screw breakages were observed; they were only in Group C (4.0%) and all were in the proximal of the two holes. Interbody and posterolateral fusion rates were not significantly different. At last follow-up, all clinical parameters including VAS-BP, VAS-LP, and K-ODI scores had improved significantly in both groups. Postoperative complications were not significantly different in the two groups.

Conclusion: In lumbar fusion surgery, using cement-augmented CPS in high-risk groups for implant failure could be a useful technical option for reducing acute radiological complications and obtaining clinical results comparable to those obtained using SPS in patients with low risk of implant failure.

Level of evidence: Level 4.

Keywords: Cement-augment cannulated screw; Clear zone; Loss of correction; Screw breakage; Screw migration; Screw pull-out.