The occurrence of a fusion mass fracture represents a rare yet significant clinical challenge in spine surgery. While clinicians often remove instrumentation to alleviate hardware-related pain or prominence, this decision requires a comprehensive risk-benefit analysis. Specifically, removing the internal support of a long-construct fusion may expose the mature bone to new mechanical stresses. This case report examines a 52-year-old woman who suffered a late fracture after hardware removal for adult idiopathic scoliosis.

A Long-Term Complication After Hardware Removal

Initially, the patient underwent a successful posterior spinal fusion to correct her deformity. However, she later requested the removal of her proximal instrumentation due to noticeable hardware prominence. Imaging at that time confirmed a solid and robust fusion mass. Consequently, surgeons performed a sequential partial removal of the rods and screws. For nine years, the patient remained asymptomatic and active. Everything changed when she sustained a low-energy injury that resulted in immediate, severe back pain. A subsequent CT scan revealed a linear fracture line through the L3-4 fusion mass, necessitating a revision surgery with new pedicle screw fixation.

Evaluating the Causes of Fusion Mass Fracture

Several biomechanical factors may contribute to a fusion mass fracture once surgeons remove the original hardware. For instance, the stress-shielding effect of long-term instrumentation might lead to device-related osteoporosis within the fusion itself. Furthermore, sagittal imbalance often places excessive strain on specific vertebral segments. If the spine lacks the rigid support of titanium rods, even a minor trauma can overcome the structural capacity of the bone. Therefore, maintaining optimal spinal alignment is crucial during the initial surgery to prevent such late failures. Moreover, surgeons should consider the potential for decreased bone mineral density in patients who have been instrumented for decades.

Clinical Lessons for Spine Surgeons

This case serves as a vital reminder that a radiographically "solid" fusion is not always indestructible. Specifically, clinicians must warn patients that hardware removal is not a risk-free procedure. While it may resolve localized discomfort, it potentially introduces instability or the risk of future fractures. Therefore, surgeons should reserve instrumentation removal for cases with clear, debilitating indications. Additionally, long-term follow-up remains essential for detecting gradual changes in spinal balance or bone health. By understanding these risks, the medical community can better guide patients through the complexities of revision spine surgery.

Frequently Asked Questions

What causes a fusion mass fracture after hardware removal?

A fusion mass fracture often occurs due to a combination of stress-shielding, underlying osteoporosis, and sagittal imbalance. When surgeons remove the hardware, the previously protected fusion mass must suddenly bear full physiological loads, which can lead to failure under stress or minor trauma.

How do surgeons treat a fracture within a fusion mass?

Treatment usually involves stabilizing the fracture site through a revision posterior spinal fusion. Surgeons typically place pedicle screws and rods at least two levels above and below the fracture to ensure adequate stability and promote healing of the bone.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or establish a doctor-patient relationship. Always seek the advice of a qualified healthcare provider regarding any medical condition or treatment. Refer to the latest local and national guidelines for clinical practice.

References

Hendricks CJ et al. Fracture of robust fusion mass after sequential long-construct instrumentation removal: illustrative case. J Neurosurg Case Lessons. 2026 Feb 16. doi: undefined. PMID: 41698195.

Makanji H, et al. Atraumatic lumbosacral fusion mass fracture: Bisphosphonates to blame? Orthopaedic Journal at Harvard Medical School. 2015.

Sellin JN, et al. Fracture of fusion mass following anterior cervical plate removal: Case report. J Clin Neurosci. 2018 Jan;47:128-131.