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Are modular pedicle screws associated with a high complication rate following posterior spinal fixation?
Andrew J Pugely1, Christopher P Lindsay1, James Hall1
1Department of Orthopedics and Rehabilitation, The University of Iowa Health Care, Iowa City, IA, USA.
Background:
Modular pedicle screws have a separate head that can be intraoperatively assembled to the inserted shank. The aim of this study was to report associated intra- and post-operative complications and reoperation rates of posterior spinal fixations with modular pedicle screws at a single center.
Methods:
A retrospective, institutional chart review was performed on 285 patients who underwent posterior thoracolumbar spinal fusion with modular pedicle screw fixation between January 1, 2017, and December 31, 2019. The primary outcome was failure of the modular screw component. Other measures recorded were length of follow-up, other complications, and need for additional procedures.
Results:
There were 1,872 modular pedicle screws (average 6.6 per case). There were no (0.0%) screw head dissociations at the rod screw junction. There was 20.8% overall complication rate (59/285) with 25 reoperations: 6 due to non-union and rod breakage, 5 for screw loosening, 7 for adjacent segment disease, 1 for acute postoperative radiculopathy, 1 for epidural hematoma, 2 for deep surgical-site infections, and 3 for superficial surgical-site infections. Other complications included superficial wound dehiscence [8], dural tears [6], non-unions not requiring reoperation [2], lumbar radiculopathies [3], and perioperative medical complications [5].
Conclusions:
This study demonstrates that modular pedicle screw fixation has reoperation rates similar to those previously reported for standard pedicle screws. There was no failure at the screw-head junction, and no increases in other complications. Modular pedicle screws present an excellent option to allow surgeons to place pedicle screws without the risk of extra complications.
Insights
Modular pedicle screws show comparable reoperation rates to standard screws in posterior spinal fusions. This study found no screw-head junction failures, indicating they are a safe option for spinal fixation.
Area of Science:
- Orthopedic Surgery
- Spinal Fusion
- Biomedical Engineering
Background:
- Modular pedicle screws feature a head assembled intraoperatively to the shank.
- Posterior spinal fixation utilizes these modular components.
Purpose of the Study:
- To evaluate intra- and post-operative complications.
- To determine reoperation rates for modular pedicle screw fixation in posterior spinal fusions.
Main Methods:
- Retrospective review of 285 patients undergoing posterior thoracolumbar spinal fusion.
- Analysis of modular pedicle screw component failure, complications, and reoperations.
Main Results:
- No screw head dissociations observed in 1,872 modular pedicle screws.
- Overall complication rate was 20.8% with 25 reoperations for various causes.
- No increase in complications compared to standard pedicle screws.
Conclusions:
- Modular pedicle screw fixation demonstrates similar reoperation rates to standard screws.
- No screw-head junction failures or increased complications were noted.
- Modular pedicle screws offer a safe and effective option for spinal fixation.

