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Zero-P VA Cervical Degenerative Disc Disease (DDD) is a common pathology and part of the natural process of aging. When DDD becomes symptomatic or painful, it can cause several different symptoms, including neck pain, nerve root pathology (eg, numbness or pain in shoulders/arms), and spinal cord compression. If pain cannot be resolved by conservative treatment, surgery might become the only option. Some patients with persistent pain or neurological deficits need surgery to relieve the symptoms.
Fig 1 Zero-P VA construct.
Today’s standard surgical treatment is to fuse the vertebrae adjacent to the diseased disc. Studies show that anterior cervical plating helps increase fusions rates [1,2], however anterior cervical plating also has potential drawbacks, such as the prolongation of OR time, the potential for postoperative dysphagia, and/or heterotopic ossification (abnormal formation of bone over time) at adjacent spinal levels. In 2008, a novel cervical fusion implant named Zero-P was introduced. The implant was designed to be fully contained within the excised disc space without protruding past the anterior wall of the vertebral body when implanted. The combination of the plate/spacer assembly with four rigid screws ensures that the construct provides similar stability [3] to traditional cervical plate and spacer constructs while offering a number of clinical advantages. These include:
Fig 2 Zero-P plate/spacer with four locking screws.
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Prevention of soft-tissue irritation Minimization of adjacent level ossification Smaller incision sizes Facilitates surgeries where Zero-P is implanted adjacent to a previous fusion.
Zero-P VA (Fig 1) complements the original Zero-P (Fig 2) by offering an implant that is based on the same fundamentals but utilizes two semi-constrained screws with variable angle insertion (Fig 3) instead of four rigid screws as a means of fixation. Zero-P VA is designed for surgeons’ ease of use. It is a stand-alone plate/spacer fusion device for indications where the stability of a two screw semi-constrained fixation is sufficient. For optimal adoption to the patient anatomy, Zero-P VA is available in various spacer shapes (convex, lordotic, parallel), two different footprint sizes and multiple height options (5–12 mm in 1 mm increments).
b Fig 3a–b Anterior (a) and lateral (b) view of Zero-P VA plate/spacer with two variable angle screws.
Zero-P VA follows a similar surgical technique to Zero-P. In a first step after discectomy and decompression, trial spacers are used to determine implant height, shape, and footprint size. Once the implant is inserted and correctly positioned, screw hole preparation is performed. For anatomically challenging situations, such as patients with short