Zero-P: a new zero-profile cage-plate device for single and multilevel ACDF. A single institution series with four years maximum follow-up and review of the literature on zero-profile devices.
OBJECTIVE
To analyze the prospectively collected data in a series of patients treated with single- or multilevel ACDF with a stand-alone, zero-profile device, focusing on clinico-radiological outcome, complications and technical hints, and to review the literature on such new devices.


METHODS
Eighty-five patients harboring symptomatic DDD underwent ACDF with the Zero-P cage-plate: 29 at 1-level and 56 at 2-4 levels (total 162 devices). In the multilevel group, 9 patients received a combination of Zero-P and stand-alone cages (hybrid implants). This study focuses on 32 patients with follow-up ranging from 20 to 48 months. NDI, SF-36 and arm pain VAS scores were registered preoperatively and at follow-up visits. Dysphagia was assessed using the Bazaz score. Imaging included X-rays, CT and MRI, also to assess the presence of vertebral body fractures in multilevel cases. Paired Student t test was used for statistical analysis.


RESULTS
SF-36 and NDI showed a statistically significant improvement (p < 0.01) and mean arm pain VAS score decreased from 79 to 41. X-rays and CT demonstrated, respectively, a 94.5 % and a 92 % fusion rate. Three patients complained of moderate and two of mild transient dysphagia (15.5 %). No device-related complications occurred and no fractures, secondary to four screws insertion in one vertebral body (i.e., swiss cheese effect), were detected in multilevel cases. In patients with extensive anterior osteophytes only a "focal spondylectomy" was required.


CONCLUSIONS
The Zero-P device is safe and efficient, even in multilevel cases. Dysphagia is minimal, extensive anterior osteophytectomy is unnecessary and technical hints may ease the surgical workflow. This is the largest series, with the longest follow-up, reported.
Neurosurgery and Radiology Departments, Policlinico "G. Rodolico" University Hospital, Viale XX Settembre 45, 95129, Catania, Italy, giuseppebarbagal@hotmail.com.
Giuseppe M V
GM
Barbagallo
Dario
D
Romano
Francesco
F
Certo
Pietro
P
Milone
Vincenzo
V
Albanese
D000328:Adult; D000368:Aged; D001860:Bone Plates; D002574:Cervical Vertebrae / Q000601:surgery*; D017586:Diskectomy / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000209:etiology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods