Mega-granuloma After Using the Universal Clamp for Adolescent Idiopathic Scoliosis: What Is It and Can It Be Prevented?

ABSTRACT

STUDY DESIGN: Clinical case series. OBJECTIVE: To characterize the postoperative course and histopathology of peri-implant tissue of adolescent idiopathic scoliosis patients who experienced postoperative development of an aseptic soft tissue reaction, with granulomas adjacent to the sublaminar polyethylene terephthalate strap-titanium clamp used in Zimmer's Universal Clamp (UC) spinal fixation system after spinal surgery. BACKGROUND SUMMARY: The UC was designed for use with spinal deformity procedures in place of pedicle screws, hooks, or sublaminar wiring in fusion constructs. Recent studies of the UC lack emphasis on implant-related postoperative complications. METHODS: A total of 26 consecutive patients who underwent spinal deformity correction for scoliosis were reviewed for implant-related postoperative complications. Histology, scanning electron microscopy with energy-dispersive X-ray spectroscopy, fractional culture/biopsy, and Gram stain examination of the peri-implant tissue of patients with complications was performed. RESULTS: The authors reviewed 26 cases for correction of scoliosis. Two patients with adolescent idiopathic scoliosis who used the UC experienced implant-related complications with development of an aseptic soft tissue reaction with granulomas adjacent to the sublaminar polyethylene terephthalate straps-titanium clamp mechanism of the UC 8 months after AIS correction surgery. There were no signs or symptoms of wound infection. Gram stain revealed no organisms. There were many neutrophils and the surface of the wound revealed rare Staphylococcus aureus but the deep portions of the wounds were negative for organisms. Histopathology revealed extensive granulation tissue and histiocytes with engulfed birefringent particles or debris, and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis revealed macrophages containing many particles identified as titanium. CONCLUSIONS: adolescent idiopathic scoliosis patients who use the novel UC construct may develop postoperative foreign-body reaction.