Enlarged anterior cervical diskectomy and fusion in the treatment of severe localised ossification of the posterior longitudinal ligament

BACKGROUND: Severe localised ossification of the posterior longitudinal ligament (OPLL) should be directly removed by anterior approach, but the exposure during anterior cervical diskectomy and fusion (ACDF) is restricted and may increase the risk of a cerebrospinal fluid (CSF) leak. Corpectomy is facilitated to extirpate the ossification, but it is relatively more invasive. The purpose of this study was to investigate the feasibility and clinical outcome of enlarged ACDF in treating severe localised OPLL. METHODS: Twenty-four selective patients with severe localised OPLL who underwent enlarged ACDF from January 2011 to July 2013 were retrospectively investigated. The Japanese Orthopaedic Association (JOA) scales, visual analogue scale (VAS), occupying rate (OR), fused segment height (FSH), sagittal segmental alignment (SSA), range of motion (ROM), and complications were investigated. RESULTS: After a mean 34.9-month follow-up, the mean JOA score increased from 9.5 ± 1.4 preoperatively to 14.1 ± 1.5 at the final follow-up (p < 0.05), while OR decreased from 58.9 ± 6.1 % pre- to 10.6 ± 5.5 % postoperatively (p < 0.05). The average VAS was 6.1 ± 1.8 preoperatively and 2.1 ± 1.4 at the final follow-up (p < 0.05). The SSA angles at the final follow-up increased 2.2° compared to the preoperative values (p < 0.05). The mean FSH increased 2.4 mm from pre- to postoperatively, but decreased 2.7 mm from postoperatively to final follow-up. The cervical ROM was not obviously reduced at the final follow-up (p > 0.05) because only one level was fixed. There were three cases of cerebrospinal fluid leakage, one case of haematoma, and one case showed transient neurological deterioration. CONCLUSIONS: Enlarged ACDF is an effective procedure for treating selective patients with severe localised OPLL. Using this technique, the retrovertebral OPLL can be removed through a one-level diskectomy and a corpectomy can be avoided. TRIAL REGISTRATION: This study has been registered with the ResearchRegistry and the unique identifying number is researchregistry1365 (K2015-022-04). It was retrospectively registered at 21 June 2016 and the first participant to the trial was at 4 January 2011. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13018-016-0449-z) contains supplementary material, which is available to authorized users.