Interspinous Wiring

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Chapter Synopsis	Interspinous wiring techniques were developed as a means of stabilizing traumatic cervical injuries. Although increasingly replaced by newer technologies, such as lateral mass screws and pedicle screws, interspinous wiring remains a useful supplemental or alternative means of posterior cervical fixation. The purpose of this chapter is to review the indications, surgical technique, and postoperative management for cervical interspinous wiring.
Important Points	Wiring offers better stabilization in flexion than in extension or rotation. If used by themselves, wiring techniques are generally supplemented with an external orthosis or halo. Several techniques have been described, but each involves wiring together of adjacent vertebrae. Contraindications include spinous process fracture and lamina fracture or extensive laminectomy.
Clinical and Surgical Pearls	Rogers wiring involves passing a wire through the cephalad spinous process and under the caudal spinous process. Bohlman triple wiring involves passing a wire through the spinous processes of both levels being addressed. Two additional wires are passed through the spinous process holes and structural graft on either side of the posterior elements. Facet wiring involves passing a wire through a drill hole in the inferior facet of the cephalad level and then around the spinous process of the caudad level.
Clinical and Surgical Pitfalls	Interspinous wiring alone may not provide sufficient fixation. It may be used as an adjunct to other instrumentation or for supplemental external immobilization. The most common complications of spinous process wiring are lack of fusion and loss of alignment.

Posterior cervical stabilization using wires was first described by Hadra in 1891 as a means to address instability secondary to fracture and Pott disease. Subsequently, Rogers described the treatment of traumatic cervical instability by using interspinous wiring in 1942. Relatively minor modifications to wiring techniques have been made over the decades, but the general concept remains similar.

Although these techniques are generally referred to as wiring techniques, wires or cables may be considered. Braided cables offer the potential merit of flexibility, strength, and improved fatigue properties. However, these cables may not be readily available, they require specific tools, and they have a tendency to return to a circular shape if loosening occurs. Interspinous wiring provides good support in flexion, but it offers much less in extension and rotation because only the midline spinous processes are stabilized.

Indications and Contraindications

Posterior cervical stabilization has many indications, including, but not limited to, traumatic cervical spine injuries, sagittal deformity, and instability resulting from congenital anomalies or inflammatory arthritis, infection, neoplasms, or anterior nonunion. The goals of internal fixation are stabilization, maintenance of alignment, enhancement of fusion, and alleviation of pain.

Interspinous wiring is contraindicated when the spinous processes are fractured or when the laminae are fractured or removed by laminectomy resulting from decompression. In these cases, facet wiring, briefly described later, can be performed. Alternatively, the vertebrae can be stabilized with wires extending from the segment above the level of spinous process fracture to the level below it.

For many applications, newer methods such as lateral mass screws and pedicle screws have replaced wiring techniques in current clinical practice because of their flexibility and ability to be placed despite removal of posterior vertebral elements. Nonetheless, interspinous wiring remains a useful technique as a result of its “low cost, decreased risk of neurologic or vascular injury and relative technical ease of instrumentation placement.” This is a good tool to maintain in the armamentarium of cervical stabilization techniques.

Of the applications for which interspinous wiring is considered, the one that is currently most common is for provisional reduction and stabilization of traumatic injuries. By facilitating reduction with the interspinous wire, the alignment of the spine can be improved before placement of lateral mass fixation. The wire is then often left or can even be considered for removal before completing the stabilization construct.

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