Does posterior longitudinal ligament resection during cervical artificial disc replacement affect the clinical or radiographic outcome?

Abstract

Background context: Much controversy exists about whether posterior longitudinal ligament (PLL) resection should be performed during cervical artificial disc replacement (ADR). The PLL can be resected or preserved during the ADR procedure based on the shape and location of the compressive pathology. However, unlike fusion operations, the outcomes of ADR may be affected by PLL resection since segmental motion is preserved with ADR and the PLL restricts flexion of the segment. Nevertheless, the effect of PLL removal during ADR in a clinical setting remains unclear.

Purpose: To investigate the effect of PLL resection on the clinical or radiographic outcomes of ADR.

Study design/setting: Retrospective cohort study.

Patient sample: A total of 113 patients who completed a minimum follow-up of 2 years after one-level ADR.

Outcome measures: Global cervical sagittal parameters, including C2-7 range of motion, C2-7 flexion and extension capacity, segmental cervical sagittal parameters, including segmental range of motion, segmental flexion and extension capacity, adjacent segmental disease (ASD), and heterotopic ossification (HO) were assessed. Patient-reported outcome measures, including the neck pain visual analog scale (VAS), arm pain VAS, and neck disability index, were recorded.

Methods: This study analyzed patients who underwent one-level ADR for soft disc herniation with or without PLL resection. ADR was performed for central or posterolateral soft disc herniation causing cervical radiculopathy or myelopathy, and a minimum 2-year follow-up. The results were compared between the PLL-preservation and -resection groups.

Results: The PLL-preservation group included 55 of the 96 patients (57.3%), and the PLL-resection group contained the other 41 patients (42.7%). The baseline patient characteristics did not differ significantly between the two groups. Furthermore, global cervical radiologic parameters, segmental sagittal parameters, and the incidence of HO or ASD at the 2-year postoperative follow-up did not differ significantly between the two groups. The patient-reported outcome measures improved significantly after surgery in both groups, without significant intergroup differences at any time point.

Conclusions: Resection of the PLL does not seem to have a significant effect on the range of motion or patient-reported symptoms. Therefore, the decision to resect the PLL during ADR should be based solely on whether it is needed for adequate decompression.