Distal Junctional Failure Secondary to Nontraumatic Fracture of Lower Instrumented Vertebra: Our Experience and Review of Literature

Abstract

Background: Junctional kyphosis (JK) is usually observed in long-level instrumented fusion surgeries. Various contributing factors are proposed, the pre-existing and postoperative spinal imbalance is considered as the single most important factor for the development of JK in adult spinal deformity surgeries. Distal JK (DJK) is seldom reported compared to proximal JK (PJK), and scarce literature exists.Methods: We report 2 unique cases of distal junctional failure (DJF) with worsening of neurology, secondary to nontraumatic fracture of a lower instrumented vertebra operated for thoracic canal stenosis without deformity. The first case had acute worsening of the Neurology during follow up and on evaluation, the supine CT and MRI scan revealed well decompressed spinal canal, no implant migration to the canal, no screw loosening, or rod failure. Supine sitting radiographs demonstrated DJK with Fracture and the patient underwent extension of fusion till the pelvis with 3-rod construct and interbody fusion, because of the instability at the L1 level. The second case remained neurologically stable for a month and then had an acute onset of back pain, sensory deficit, and urine incontinence. The supine-sitting dynamic radiograph done demonstrated L1 fracture with DJK at D12-L1 levels. The patient was counseled for extension of fusion, which was deferred by the patient.Results: Patients in our series, had an acute worsening of neurological deficit within a month of posterior spinal fixation. Their supine imaging was almost normal, and the diagnosis of DJK with L1 fracture instability was possible only on a supine-sitting dynamic radiograph. Various factors like obesity, TL kyphosis, osteoporosis, etc. can be the attributing factors for the development of DJK Conclusion: A high index of suspicion is required for diagnosing nontraumatic fracture in long-level fusion patients with acute neurological worsening. The supine-sitting dynamic radiograph is an important diagnostic tool for DJF in patients having difficulty standing erect.Level of Evidence: 4. Clinical Relevance: Application of sitting and supine dynamic radiographs to diagnose instability in patients unable to stand for flexion and extension radiographs.

Distal Junctional Failure due to Spondylodiscitis in a Patient with Long Posterior Fixation for Ossified Longitudinal Ligament and Ossified Ligamentum Flavum

“…The challenge is increased manifold in the presence of infection. DFJ is underreported when compared to PFJ, and the factors contributing to DFJ have always remained elusive [ 3 , 4 , 6 ]. In the past, JF has been broadly classified either due to failure of instruments, problems at the instrument-bone interface, or accelerated adjacent disc-level degeneration.…”

“…Distal junctional failure (DJF) is rare when compared to proximal junctional failure (PJF). Therefore, the cause of DFJ also remains relatively unexplored [ 3 , 4 ].…”

Dynamic cord compression induced by proximal junctional failure and loose pedicle screws after thoracolumbar fusion surgery: a case report

“…MRI and CT are accurate for assessing changes in the intervertebral disc, fracture, and associated spinal cord compression and cord edema [ 19 , 24 ]. However, one study reported that supine MRI and CT may miss the spinal cord compression induced by dynamic instability [ 25 ]. The authors of that study reported two cases in which long thoracic fusion surgery induced a vertebral fracture at the distal side that was accompanied by dynamic instability.…”

“…The authors of that study reported two cases in which long thoracic fusion surgery induced a vertebral fracture at the distal side that was accompanied by dynamic instability. Supine imaging showed almost normal alignment, but a sitting X-ray revealed severe kyphotic alignment [ 25 ]. Another study reported that long thoracolumbar fusion surgery in a patient with diffuse idiopathic skeletal hyperostosis caused PJF or fracture and more severe dynamic instability [ 26 ].…”

Risk Factors for Distal Junctional Problems Following Long Instrumented Fusion for Degenerative Lumbar Scoliosis: Are they Related to the Paraspinal Muscles

“… 7 This finding indicates that although the incidence of DJPs is lower than that of PJK/PJF, affected patients are more likely to require revision surgery when they occur. 8 , 9 The pathogenic mechanisms underlying DJPs are multifactorial, and older age, 7 large preoperative sagittal parameters, 10 fusion short of including the first lordotic disc, 11 selection of the incorrect lowest instrumented vertebra (LIV), 12 , 13 and inability to match the postoperative sagittal plane with the pelvic incidence (PI) 14 have been reported to be involved. Recently, lower muscularity and higher fatty degeneration have been reported as risk factors for PJK.…”