Novel Distributed Loading Technique Using Multimaterial, Long-Segment Spinal Constructs to Prevent Proximal Junctional Pathology in Adult Spinal Deformity Correction—Operative Technique and Radiographic Findings

Proximal junctional kyphosis (PJK) and proximal junction failure are common and costly complications after long-segment adult spinal deformity (ASD) correction. Although much research has focused on the concept of “softening the landing” to prevent proximal junction pathologies, long-segment constru...

Full description

Saved in:
Bibliographic Details
Published in:World neurosurgery 2021-11, Vol.155, p.e264-e270
Main Authors: Tempel, Zachary J., Hlubek, Randall J., Kachmann, Michael C., Body, Alaina, Okonkwo, David O., Kanter, Adam S., Buchholz, Avery L., Krueger, Bryan M.
Format: Article
Language:English
Subjects:
Adjacent segment disease
Adult spinal deformity
Aged
Deformity correction
Distributed loading
Humans
Kyphosis - complications
Middle Aged
Neurosurgical Procedures - adverse effects
PJK
Postoperative Complications - pathology
Postoperative Complications - prevention & control
Postoperative Complications - surgery
Proximal junctional kyphosis
Retrospective Studies
Spinal Curvatures - surgery
Spine - pathology
Spine - surgery
Spine biomechanics
Young’s modulus
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Proximal junctional kyphosis (PJK) and proximal junction failure are common and costly complications after long-segment adult spinal deformity (ASD) correction. Although much research has focused on the concept of “softening the landing” to prevent proximal junction pathologies, long-segment constructs largely deviate from the force-deformation curve of the physiologic spine. Our novel distributed loading technique for ASD correction is described using multimaterial, long-segment constructs to create a biomechanically sound, yet physiologic, decremental stiffness toward the rostral end. Operative steps detail the custom-designed constructs of dual-headed pedicle screws and varied rod diameters and materials (cobalt chromium or titanium) for an initial 20 patients (mean 66.6 ± 4.8 years). Standing scoliosis films were obtained preoperatively and at regular intervals postoperatively to assess for PJK. No patient had evidence of PJK or proximal junction failure at latest radiographic follow-up (mean 17.9 months, range 13−25 months). Radiographic findings for sagittal vertical axis averaged 11.2 ± 5.6 cm preoperatively and 3.6 ± 2.3 cm postoperatively. Compared with preoperative parameters, postoperative reductions in pelvic incidence-lumbar lordosis mismatch averaged 28.7 ± 12.9 degrees, and sagittal vertical axis averaged 7.6 ± 5.2 cm while PJA was essentially unchanged. Preliminary results suggest that the distributed loading technique is promising for prevention of PJK with stiffness gradients that mimic the force-deformation curve of the physiologic posterior tension band. Our technique may optimize the degree of stress at the proximal junction without overwhelming the anterior column bony while remodeling and mature arthrodesis takes place.
ISSN:1878-8750
1878-8769
DOI:10.1016/j.wneu.2021.08.052