Posterior Cervical Wiring Techniques

Before the popularity of lateral mass screws, posterior wiring techniques were the mainstay for posterior cervical spinal fixation. Initially, wiring was accomplished with monofilament stainless steel wire. Cable systems were then developed to circumvent the problems inherent in monofilament wiring, such as the application of uneven tension leading to breakage and their inherent stiffness, thought to increase the risk of sublaminar placement. Although currently braided cables are more commonly used, for purposes of this chapter, these techniques are considered identical.

18.2 Patient Selection

Contemporary techniques for segmental fixation, such as lateral mass screws and pedicle screws, offer superior immobilization and rigidity and are thus considered the mainstay of posterior cervical fixation. That being said, familiarity with cervical wiring techniques is still important as a backup or salvage technique in both the atlantoaxial and subaxial cervical spine if the initial instrumentation plan becomes technically difficult or unattainable because of anatomical constraints. In addition, posterior cervical wiring techniques remain a useful adjunct to other fixation techniques for the biomechanical ability of spinous process wires to resist a flexion moment. Thus, they may be used to complement anterior fusion and to recreate a posterior tension band, particularly in multilevel degenerative disease, infection, tumor, or trauma ( ▶ Fig. 18.1). Finally, wiring techniques, particularly spinous process techniques, may frequently be useful for temporary reduction of flexion deformities during the placement of segmental instrumentation. An important limitation is that wiring demands intact posterior elements. A relative contraindication would be compromised anterior and middle columns, as the wiring relies on an intact middle column and cannot remedy a loss of anterior column integrity (see ▶ text box).

Fig. 18.1 (a) Sagittal noncontrast T2-weighted magnetic resonance imaging of the cervical spine. This patient has suffered a traumatic C5 flexion compression injury with C5 burst fracture and complete disruption of the posterior ligamentous complex. A severe spinal cord injury is apparent. (b) Lateral plain radiograph of the same patient 1 year postoperatively. After decompression and reconstruction of the anterior column, a posterior tension band has been re-established using a spinous process cable.

The different categories of wiring, each with inherent advantages and disadvantages (spinous process, facet, and sublaminar) are detailed hereafter ( ▶ Table 18.1). Atlantoaxial wiring will be discussed in another chapter.

Contraindications to Posterior Cervical Wiring

Posterior element fractures.
Severe osteoporosis
Instability in anterior/middle columns
Preoperative preparation

**Table 18.1** Advantages and disadvantages of each of the wiring techniques
Technique	Advantages	Disadvantages
Spinous process wiring	Safe and simple	Poor resistance to extension requires posterior elements
Facet wiring	Simple and safe Lamina not required	Easy avulsion from facet
Sublaminar wiring	Simple Excellent tension	Spinal cord injury

A similar setup to lateral mass screw instrumentation is utlized; unstable cervical spine patients will need immobilization preoperatively and while being positioned in a rigid cervical collar, halo, or traction device. Once the patient is positioned prone and the skull fixation is locked into place, the orthosis is removed ( ▶ Fig. 18.2). Care is given to avoid any pressure sores or suprascapular nerve or brachial plexus palsies. Antibiotics are given, and preparation of the posterior neck per protocol is performed. A radiograph is recommended at this point to ensure adequate alignment when there is a potential for malalignment (i.e., with unstable fractures). Intraoperative neurophysiologic monitoring is used by some surgeons for this procedure. If used, baseline potentials should be obtained at this time.

Fig. 18.2 Patient is carefully positioned prone for posterior cervical wiring. The cranium is placed in fixation. Depending on preference, the cranium may be fixed to the table, or cervical traction may be used by means of a weight and pulley system.

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