Zero-profile hybrid fusion construct versus 2-level plate fixation to treat adjacent-level disease in the cervical spine

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Single-level anterior cervical discectomy and fusion (ACDF) is an established surgical treatment for cervical myelopathy. Within 10 years of undergoing ACDF, 19.2% of patients develop symptomatic adjacent-level degeneration. Performing ACDF adjacent to prior fusion requires exposure and removal of previously placed hardware, which may increase the risk of adverse outcomes. Zero-profile cervical implants combine an interbody spacer with an anterior plate into a single device that does not extend beyond the intervertebral disc space, potentially obviating the need to remove prior hardware. This study compared the biomechanical stability and adjacent-level range of motion (ROM) following placement of a zero-profile device (ZPD) adjacent to a single-level ACDF against a standard 2-level ACDF.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>In this in vitro biomechanical cadaveric study, multidirectional flexibility testing was performed by a robotic spine system that simulates flexion-extension, lateral bending, and axial rotation by applying a continuous pure moment load. Testing conditions were as follows: 1) intact, 2) C5–6 ACDF, 3) C4–5 ZPD supraadjacent to simulated fusion at C5–6, and 4) 2-level ACDF (C4–6). The sequence of the latter 2 test conditions was randomized. An unconstrained pure moment of 1.5 Nm with a 40-N simulated head weight load was applied to the intact condition first in all 3 planes of motion and then using the hybrid test protocol, overall intact kinematics were replicated subsequently for each surgical test condition. Intersegmental rotations were measured optoelectronically. Mean segmental ROM for operated levels and adjacent levels was recorded and normalized to the intact condition and expressed as a percent change from intact. A repeated-measures ANOVA was used to analyze the ROM between test conditions with a 95% level of significance.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>No statistically significant differences in immediate construct stability were found between construct Patterns 3 and 4, in all planes of motion (p &gt; 0.05). At the operated level, C4–5, the zero-profile construct showed greater decreases in axial rotation (–45% vs –36%) and lateral bending (–55% vs –38%), whereas the 2-level ACDF showed greater decreases in flexion-extension (–40% vs –34%). These differences were marginal and not statistically significant. Adjacent-level motion was nearly equivalent, with minor differences in flexion-extension.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>When treating degeneration adjacent to a single-level ACDF, a zero-profile implant showed stabilizing potential at the operated level statistically similar to that of the standard revision with a 2-level plate. Revision for adjacent-level disease is common, and using a ZPD in this setting should be investigated clinically because it may be a faster, safer alternative.</jats:p></jats:sec>

Cervical Stand-Alone Polyetheretherketone Cage versus Zero-Profile Anchored Spacer in Single-Level Anterior Cervical Discectomy and Fusion : Minimum 2-Year Assessment of Radiographic and Clinical Outcome

“…First, Zero-P could reduce the volume of the anterior plate, which might reduce post-operative dysphagia and simultaneously fix the cage strongly between the segments. Several published studies support this hypothesis without any significant disadvantage in clinical and radiographic results 1 6 7 8 10 14 16 17 20 21 22 25 26) . However, most of the studies compared Zero-P with the anterior plate method alone.…”

Surgical Strategy and Clinical Efficacy Analysis of Adjacent Segment Disease After Anterior Cervical Discectomy and Fusion

“…Previous studies have demonstrated that the development of ASD may be in uenced by the number and location of fusion segments, plate-to-disc distances, preexisting degenerative changes at adjacent segments, and excessive disc space distraction [15]. However, Zero-p interbody fusion system features Low notch, self-anchoring, and a onepiece interbody fusion device that supports and xes the segmental vertebrae [16]. It can be integrated into the intervertebral space without exceeding the anterior edge of the vertebral body, and no anterior titanium plate xation is required, which can effectively avoid the injury and stimulation of the prevertebral soft tissue and esophagus caused by the traditional titanium plate, and avoid the in uence of the traditional titanium plate on adjacent segments, thus effectively reducing the incidence of postoperative dysphagia and degeneration of adjacent segments of the cervical vertebra.…”

“…It can be integrated into the intervertebral space without exceeding the anterior edge of the vertebral body, and no anterior titanium plate xation is required, which can effectively avoid the injury and stimulation of the prevertebral soft tissue and esophagus caused by the traditional titanium plate, and avoid the in uence of the traditional titanium plate on adjacent segments, thus effectively reducing the incidence of postoperative dysphagia and degeneration of adjacent segments of the cervical vertebra. The clinical effect of the zero-p intervertebral fusion system in the treatment of cervical degenerative diseases has been widely studied [16][17][18]. However, there are relatively fewer studies on symptomatic ASD after ACDF.…”

The Effectiveness of the Most Used Techniques in Patients With Degenerative Cervical Disease

“…Although this surgical technique is better suited to the condition of the patient, it has disadvantages, such as increased surgical time and intraoperative blood loss, an increased rate of heterotopic ossification, the possibility of vertebral body fractures, dislocation of the implant (if not properly placed), and the possible loss of cervical lordosis. 13,[16][17][18] In addition to choosing the appropriate surgical technique for the patient's clinical and radiographical condition, other factors also influence and are considered predictors of the outcome and quality of life of the patient after the surgical procedure. The factors that predict poor prognosis of surgical outcomes can be divided into two distinct groups: those related to the patient and those related to the imaging examinations (magnetic resonance and computed tomography).…”