Best of 2016

OBJECTIVE

The purpose of this study was to report the outcome of a study of 2-level cervical total disc replacement (Mobi-C) versus anterior cervical discectomy and fusion (ACDF). Although the long-term outcome of single-level disc replacement has been extensively described, there have not been previous reports of the 5-year outcome of 2-level cervical disc replacement.

METHODS

This study reports the 5-year results of a prospective, randomized US FDA investigational device exemption (IDE) study conducted at 24 centers in patients with 2-level, contiguous, cervical spondylosis. Clinical outcomes at up to 60 months were evaluated, including validated outcome measures, incidence of reoperation, and adverse events. The complete study data and methodology were critically reviewed by 3 independent surgeon authors without affiliation with the IDE study or financial or institutional bias toward the study sponsor.

RESULTS

A total of 225 patients received the Mobi-C cervical total disc replacement device and 105 patients received ACDF. The Mobi-C and ACDF follow-up rates were 90.7% and 86.7%, respectively (p = 0.39), at 60 months. There was significant improvement in all outcome scores relative to baseline at all time points. The Mobi-C patients had significantly more improvement than ACDF patients in terms of Neck Disability Index score, SF-12 Physical Component Summary, and overall satisfaction with treatment at 60 months. The reoperation rate was significantly lower with Mobi-C (4%) versus ACDF (16%). There were no significant differences in the adverse event rate between groups.

CONCLUSIONS

Both cervical total disc replacement and ACDF significantly improved general and disease-specific measures compared with baseline. However, there was significantly greater improvement in general and disease-specific outcome measures and a lower rate of reoperation in the 2-level disc replacement patients versus ACDF control patients.

Clinical trial registration no. NCT00389597 (clinicaltrials.gov)

OBJECTIVE

The purpose of this study was to report the long-term clinical outcomes following 3- and 4-level anterior cervical discectomy and fusion (ACDF).

METHODS

A retrospective review of all adult neurosurgical patients undergoing elective ACDF for degenerative disease at a single institution between 1996 and 2013 was performed. Patients who underwent first-time 3- or 4-level ACDF were included; patients with previous cervical spine surgery, those undergoing anterior/posterior approaches, and those with corpectomy were excluded. Outcome measures included perioperative complication rates, fusion rates, need for revision surgery, Nurick Scores, Odom's criteria, symptom resolution, neck visual analog scale (VAS) pain score, and persistent narcotics usage.

RESULTS

Seventy-one patients who underwent 3-level ACDF and 26 patients who underwent 4-level ACDF were identified and followed for an average of 7.6 ± 4.2 years. There was 1 case (3.9%) of deep wound infection in the 4-level group and 1 case in the 3-level group (1.4%; p = 0.454). Postoperatively, 31% of patients in the 4-level group complained of dysphagia, compared with 12.7% in the 3-level group (p = 0.038). The fusion rate was 84.6% after 4-level ACDF and 94.4% after 3-level ACDF (p = 0.122). At last follow-up, a significantly higher proportion of patients in the 4-level group continued to have axial neck pain (53.8%) than in the 3-level group (31%; p = 0.039); the daily oral morphine equivalent dose was significantly higher in the 4-level group (143 ± 97 mg/day) than in the 3-level group (25 ± 10 mg/day; p = 0.030). Outcomes based on Odom's criteria were also different between cohorts (p = 0.044), with a significantly lower proportion of patients in the 4-level ACDF group experiencing an excellent/good outcome.

CONCLUSIONS

In this study, patients who underwent 4-level ACDF had significantly higher rates of dysphagia, postoperative neck pain, and postoperative narcotic usage when compared with patients who underwent 3-level ACDF. Pseudarthrosis and deep wound infection rates were also higher in the 4-level group, although this did not reach statistical significance. Additionally, a smaller proportion of patients achieved a good/excellent outcome in the 4-level group than in the 3-level group. These findings suggest a significant increase of perioperative morbidity and worsened outcomes for patients who undergo 4- versus 3-level ACDF.

OBJECT

The aim of the study was to investigate the safety and efficacy of minimally invasive tubular microdiscectomy for the treatment of recurrent lumbar disc herniation (LDH). As opposed to endoscopic techniques, namely microendoscopic and endoscopic transforaminal discectomy, this microscopically assisted technique has never been used for the treatment of recurrent LDH.

METHODS

Thirty consecutive patients who underwent minimally invasive tubular microdiscectomy for recurrent LDH were included in the study. The preoperative and postoperative visual analog scale (VAS) scores for pain, the clinical outcome according to modified Macnab criteria, and complications were analyzed retrospectively. The minimum follow-up was 1.5 years. Student t-test with paired samples was used for the statistical comparison of pre- and postoperative VAS scores. A p value < 0.05 was considered to be statistically significant.

RESULTS

The mean operating time was 90 ± 35 minutes. The VAS score for leg pain was significantly reduced from 5.9 ± 2.1 preoperatively to 1.7 ± 1.3 postoperatively (p < 0.001). The overall success rate (excellent or good outcome according to Macnab criteria) was 90%. Incidental durotomy occurred in 5 patients (16.7%) without neurological consequences, CSF fistula, or negative influence to the clinical outcome. Instability occurred in 2 patients (6.7%).

CONCLUSIONS

The clinical outcome of minimally invasive tubular microdiscectomy is comparable to the reported success rates of other minimally invasive techniques. The dural tear rate is not associated to higher morbidity or worse outcome. The technique is an equally effective and safe treatment option for recurrent LDH.