Can patient-specific precontoured rod instrumentation reduce the rate of proximal junctional kyphosis for adult spinal deformity? A propensity score-matched analysis.

Authors

Michael W Fields, Joseph M Lombardi, Nathan J Lee, Gabriella Greisberg, Justin L Reyes, Mark M Herbert, Matan S Malka, Cole Morrissette, Zeeshan M Sardar, Lawrence G Lenke, Ronald A Lehman

Published in

Journal of neurosurgery. Spine. Pages 1-6. Jun 19, 2026. Epub Jun 19, 2026.

Abstract

The objective of this study was to determine whether patient-specific precontoured rod (PCR) instrumentation is associated with lower rates of proximal junctional kyphosis (PJK) compared with manually contoured conventional rods (CRs) in adult spinal deformity (ASD) surgery.
The data of ASD patients (age ≥ 18 years) undergoing posterior spinal instrumentation and fusion of a minimum of 5 levels were consecutively reviewed from 2016 to 2021. A propensity score-matching algorithm was used to match patients undergoing instrumentation with PCRs (n = 80) to those treated with CRs (n = 210). The primary outcome was the rate of radiographic PJK at a minimum follow-up of 1 year. PJK was defined by two criteria: a postoperative proximal junctional sagittal angle (PJA) 1) ≥ 10° and 2) at least 10° greater than the preoperative measurement.
Following propensity score matching, 160 patients were included in the study (80 per group). Patients demonstrated similar preoperative baseline characteristics and preoperative radiographic alignment. Preoperatively, the mean PJAs measured 9.24° ± 6.8° and 8.8° ± 7.3° for the PCR and CR groups, respectively (p = 0.751). At the most recent follow-up, the PCR and CR groups demonstrated mean PJAs of 11.6° ± 9.1° and 10.8° ± 8.3°, respectively (p = 0.545). Ten (12.5%) patients experienced PJK in the PCR group compared to 16 (20%) patients in the CR group (p = 0.199). In patients with upper instrumented vertebrae in the lower thoracic region, 5 (11.1%) patients in the PCR group experienced PJK versus 12 (26.7%) patients in the CR group (p = 0.059). Furthermore, 7 (10.9%) patients in the PCR group experienced PJK compared to 14 (21.5%) patients in the CR group after including patients with fusion to the sacrum/pelvis (p = 0.103).
Lower rates of PJK were observed in the PCR group when compared to the CR cohort. However, this relationship was not statistically significant. Future studies with longer-term follow-up and larger sample sizes are warranted to investigate the relationship between PCR instrumentation and PJK prophylaxis. While PCR technology alone is likely not a definitive solution for preventing PJK, its strength lies in enabling rigorous preoperative planning and thoughtful deformity correction strategies. When integrated into a comprehensive approach to patient optimization, alignment, and junctional control, PCRs may serve as a useful adjunct in mitigating PJK risk.

PMID:
42320061
Bibliographic data and abstract were imported from PubMed on 20 Jun 2026.

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