Pedicle screws, rods, and interbody cages are engineered to withstand the mechanical demands of the spine — but they are not indestructible. Hardware failure after spinal fusion affects a meaningful percentage of patients, particularly those with long fusion constructs, poor bone quality, or fusions that did not achieve solid bone healing.
What hardware failure looks like
The most common form of hardware failure is rod fracture — a break in one of the connecting rods that holds the pedicle screws in alignment. Rod fracture typically occurs at a pseudarthrosis site — a level where the intended fusion did not occur, leaving the hardware to bear repetitive mechanical stress without the support of solid bone. Over time that stress causes metal fatigue and eventually a fracture.
Other forms include screw loosening — where a pedicle screw backs out of the vertebra — and cage migration, where an interbody cage shifts from its intended position in the disc space.
Symptoms to watch for
Hardware failure does not always cause immediate dramatic symptoms. Some patients notice a sudden change in their back pain — a new quality, a new location, or a return of pain that had been well-controlled. Others notice a change in their posture or a visible step-off in their back. Imaging is required to confirm the diagnosis.
If you have had spine surgery and notice any of the following, seek evaluation: return of significant back pain after a period of improvement, new or worsening neurological symptoms, a visible change in posture, or pain that feels different from your pre-surgical baseline.
What can be done
Not all hardware failure requires immediate revision surgery. The decision depends on whether the failure is causing symptoms, whether the spine is stable despite the hardware failure, and the patient's overall health and surgical risk. When revision is indicated, the goals are to remove the failed hardware, achieve solid fusion at the non-union site, and restore spinal stability and alignment.
Dr. Enguidanos has extensive experience with revision spine surgery including hardware removal and replacement. If you have had prior spine surgery and are concerned about hardware failure, a consultation with imaging review is the right next step.