An Adjunctive Use Of Asfotase Alfa and Zoledronic Acid After Spinal Surgery In Neurofibromatosis Type 1 Related Dystrophic Scoliosis

ABSTRACT Objective Dystrophic scoliosis is a serious skeletal manifestation of neurofibromatosis 1 (NF1). The condition requires surgical intervention that is frequently associated with poor outcome due to the high rate of impaired bone healing, pseudoarthrosis, and loosening of the spinal instrumentation. New therapeutic approaches are needed to improve surgical outcomes. Methods Clinical, laboratory, and radiographic data are presented. Results A 54-year-old woman with severe NF1 related dystrophic scoliosis and 3 prior surgical interventions underwent revision of lumbar fusion with intraoperative recombinant human bone morphogenetic protein (rhBMP-2) for loosening and a fracture of the left vertical rod at the L4 pedicle screw connection. Two days after surgery, a computed tomography (CT) scan revealed a left posterior iliac periscrew fracture. Given a high risk of mechanical failure, zoledronic acid and asfotase alfa were also administered at 3 and 7 months after surgery. At 14 months after surgery, back pain improved, and a CT scan showed stable spinal fusion and a healed left posterior iliac screw fracture. Conclusion Combination therapy including asfotase alfa with rhBMP-2 and bisphosphonate resulted in solid arthrodesis after spinal surgery in NF1-related dystrophic scoliosis. Abbreviations ALP alkaline phosphatase BSALP bone specific ALP CTx C-telopeptide HPP hypophosphatasia NF1 neurofibromatosis 1 NTx N-telopeptide P1NP procollagen type 1 intact N terminal pro PLP pyridoxal 5′-phosphate PPi inorganic pyrophosphate rhBMPs recombinant human bone morphogenetic protein