Presumptive Long Rod Technique (PLRT) for Revision Extension Instrumented Spine Surgery: A Technical Note

Abstract

Background: Revision spine surgery needing extension of fixation either require complete exposure of previously operated levels for rod exchange or can be managed by linking the new surgical construct (NSC) to primary surgical construct (PSC) with dominos. Presumptive long rod technique (PLRT) provides additional length of rod for domino placement. Case report: 80-year male on conservative management developed acute cauda equina syndrome retention due to pre-existing multilevel lumbar stenosis and acute big sequestrated disc prolapse at L12. Emergent surgical intervention in form of L1 to L4 pedicle screw fixation with postero-lateral bone grafting and fragmentectomy was done. Peri-operative period was uneventful. He was started on Teriperatide 20mcg daily with progressive mobilization and physiotherapy. At 4 months of follow-up, he developed L1 osteoporotic fracture with proximal junctional kyphosis (PJK). Patient underwent T12-L1 interbody fusion with extension of fixation to T10 which required complete opening up of previous incision as it was an Indian implant set. A domino of larger foot print couldn’t be accommodated in the space available between L1- L2 screws. Owing to severe osteoporosis and degenerative changes at proximal levels, presumptive oversized rods were inserted with extra lengths of the rods left at proximal ends. This technique is labelled PLRT(presumptive long rod technique) at our institute. At 6 months of follow up, patient developed T10 osteoporotic fracture with PJK and patient was planned for extension of fixation upto T4. Since the extra lengths of rods were available at proximal ends, only the planned operative levels were exposed and it was connected to previous construct using the larger footprint domino. Patient improved clinically and was ambulatory. The patient expired at 18 months due to cardio-respiratory arrest unrelated to the spinal events. Conclusion: Additional rod lengths intentionally left at adjacent levels during primary surgery where there is anticipation of PJK and adjacent segment disease (ASD) can be a boon when there is need for extension of fixation. These extra lengths of rod can be used to place dominos and connect PSC to NSC without the need for exposure of PSC levels for rod exchange, preventing complications especially in setups with economic constraints. Keywords: Complex, Adult Spinal Deformity, Adjacent Segment, Junctional Kyphosis, Osteoporosis, Revision, Surgery, Multirod.