Long-term results of the NECK trial—implanting a disc prosthesis after cervical anterior discectomy cannot prevent adjacent segment disease

The Spine Journal 23 (2023) 350−360

Motion preserving anterior cervical disc arthroplasty (ACDA) in patients with cervical radiculopathy was introduced to prevent symptomatic adjacent segment disease as compared to anterior cervical discectomy and fusion (ACDF).

PURPOSE: To evaluate the long-term outcome in patients with cervical radiculopathy due to a herniated disc undergoing ACDA, ACDF or ACD (no cage, no plate) in terms of clinical outcome measured by the Neck Disability Index (NDI). Likewise, clinically relevant adjacent segment disease is assessed as a long-term result.

STUDY DESIGN: Double-blinded randomized controlled trial.

PATIENT SAMPLE: A total of 109 patients with one level herniated disc were randomized to one of the following treatments: ACDA, ACDF with intervertebral cage, ACD without cage.

OUTCOME MEASURES: Clinical outcome was measured by patients’ self-reported NDI, Visual Analogue Scale (VAS) neck pain, VAS arm pain, SF36, EQ-5D, perceived recovery and reoperation rate. Radiological outcome was assessed by radiographic cervical curvature and adjacent segment degeneration (ASD) parameters at baseline and up until five years after surgery.

METHODS: To account for the correlation between repeated measurements of the same individual Generalized Estimated Equations (GEE) were used to calculate treatment effects, expressed in difference in marginal mean values for NDI per treatment group.

RESULTS: Clinical outcome parameters were comparable in the ACDA and ACDF group, but significantly worse in the ACD group, though not reaching clinical relevance. Annual reoperation rate was 3.6% in the first two years after surgery, declined to 1.9% in the years thereafter. The number of reoperations for ASD was not lower in the ACDA group, while the number of reoperations at the index level was higher after ACD, when compared to ACDF and ACDA.

CONCLUSIONS: A persisting absence of clinical superiority was demonstrated for the cervical disc prosthesis five years after surgery. Specifically, clinically relevant adjacent level disease was not prevented by implanting a prosthesis. Single level ACD without implanting an intervertebral device provided worse clinical outcome, which was hypothesized to be caused by delayed fusion. This stresses the need for focusing on timely fusion in future research.

Effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blinded randomised controlled trial

The Spine J Volume 19, Issue 6, Pages 965–975. 2019

Motion preserving anterior cervical disc arthroplasty (ACDA) in patients with cervical radiculopathy was introduced to prevent symptomatic adjacent disc degeneration as compared to anterior cervical discectomy and fusion (ACDF). Prior reports suggest that ACDF is not more effective than anterior cervical discectomy (ACD) alone for the treatment of cervical radiculopathy.

Purpose: To evaluate whether patients with cervical radiculopathy due to a herniated disc benefit more from undergoing ACDA, ACDF, or ACD in terms of clinical outcome measured by the Neck Disability Index (NDI).

Study design: Double-blinded randomized controlled trial

Methods: One hundred-nine patients with one level herniated disc were randomized to one of the following treatments: ACDA, ACDF with intervertebral cage, ACD without fusion. Clinical and radiological outcome was measured by NDI, Visual Analogue Scale (VAS) neck pain, VAS arm pain, SF36, EQ-5D, patients’ self-reported perceived recovery, radiographic cervical curvature, and adjacent segment degeneration (ASD) parameters at baseline and until two years after surgery. BBraun Medical paid €298.837 to cover the costs for research nurses.

Results: The NDI declined from 41 to 47 points at baseline to 19±15 in the ACD group, 19± 18 in the ACDF group, and 20±22 in the ACDA group after surgery (p=0.929). VAS arm and neck pain declined to half its baseline value and decreased below the critical value of 40 mm. Quality of life, measured by the EQ-5D, increased in all three groups. ASD parameters were comparable in all three groups as well. No statistical differences were demonstrated between the treatment groups.

Conclusions: The hypothesis that ACDA would lead to superior clinical outcome in comparison to ACDF or ACD could not be confirmed during a two-year follow-up time period. Single level ACD without implanting an intervertebral device may be a reasonable alternative to ACDF or ACDA.

Outpatient Anterior Cervical Discectomy and Fusion: Indications and Clinical Experience in a Consecutive Series of 390 Patients

Neurosurg Q 2010;20:107–110

Objective: To assess the safety and efficacy of outpatient anterior cervical discectomy and fusion (ACDF) carried out on outpatients.

Methods: We retrospectively reviewed the records of 390 consecutive patients who underwent outpatient ACDF between September 2002 and September 2007 to assess the safety and efficacy of outpatient anterior cervical surgery. The mean age of the patient sample was 46; 56% were female and 44% were male. Indications for surgery consisted of cervical radiculopathy or myelopathy. Charts were reviewed to define patient demographics and medical comorbidities. Operative data, including levels treated, surgery time, time to discharge, and intraoperative complications were collected. Clinical outcomes were collected using the PhDx Clinical Outcomes Database. Need for hospital transfer from the ambulatory surgical center, emergency room visits, and subsequent hospital admission in the perioperative period were determined from patient records. Complications, patient satisfaction, and outcome were ascertained through review of notes from the first postoperative visit.

Results: There was no mortality and there were no major complications. Out of 390 patients, operation was carried out at 1 level in 223 patients, at 2 levels in 143, and at 3 levels in 24. Pain was present in 99%, motor deficit in 31%, and myelopathy in 14%. Twenty-five percent were hypertensive, 5% were diabetic, and 2% had coronary artery disease. The incidence of hospital transfer for ACDF related complications was <1%, emergency room visits <1% and subsequent hospitalization <1%. At the time of the first postoperative visit 92% of patients believed that they were improved and only 1% of patients had transiently increased radicular weakness.

Conclusion: Outpatient ACDF is safe and efficacious in selected patients.