Percutaneous Posterior Cervical Fusion for Trauma

Tony Tannoury

Akhil Tawari

Mustafa Turki

Chadi Tannoury

Minimally invasive spinal approaches are likely to reduce exposure to the surgical area and thereby limit the collateral tissue damage and associated morbidities including bleeding, chances of infection, and postoperative pain. Additionally, less dissection tends to hasten postsurgical recovery and rehabilitation.

Anterior cervical decompression and fusion via the Smith-Robinson technique and posterior open decompression and instrumented fusion with lateral mass and/or pedicle screws and rods are currently the most widely deployed methods for the management of cervical trauma. Apart from the local anatomic risks to the surrounding structures and the traditional risks associated with open surgeries, both the standard anterior and posterior techniques are relatively of low and comparable risks. This might be a reason for the delay in the development and the adoption of percutaneous minimally invasive approaches to the cervical spine.

Posterior open surgical technique involves extensive muscle dissection and sacrifice of the posterior tension band structures. MIS techniques, in theory, limit soft tissue stripping and respect the integrity of posterior dynamic tension band.

Placement of percutaneous lateral mass screw and rod constructs utilizing tubular dilators have been described.¹,² However, this technique has been limited to three or fewer instrumented levels as a result of difficulties with rod insertion spanning multiple levels.¹

Another technique is the percutaneous transfacet screw, first described by Takayasu et al.³ in an open surgery setting. A number of recent reports have described placement of these screws in a minimally invasive manner.⁴, ⁵, ⁶ Transfacet screws have biomechanical properties that are similar to lateral mass screws and can be utilized in the absence of lamina as fixation device following laminectomy. However, the transfacet screws have a greater pullout strength by virtue of four cortices engagement, when compared with the lateral mass screws.⁷

POSITIONING AND TECHNIQUE

The placement of minimally invasive instrumentation in the cervical spine including transfacet screws, lateral mass screws, and pedicle screws is technically challenging. These techniques require a thorough understanding of the anatomy, heavy reliance on preoperative and intraoperative imaging technologies, and are associated with a sharp learning curve.

Appropriate patient positioning is essential for posterior percutaneous placement of lateral mass and transfacet screws. The procedure is performed with the patient in the prone position. A Mayfield or Gardner wells tongs can be applied to control the head and neck position at all times. It is necessary to ensure that the head and neck are in neutral position at all times and that high-quality fluoroscopic images are available. Three-dimensional imaging can also be a very useful guidance tool.

Percutaneous Lateral Mass Screw Placement Technique

Surgical Technique

With the patient in prone position, a midline (or paramedian, depending on the neck girth) skin incision, approximately one to two spinal segments caudal to the level of interest, is performed after infiltrating the skin with a local anesthetic (Fig. 14.1A). Note that this procedure is preferably carried out after adequate fracture close reduction and alignment of the facets are achieved. Following sharp dissection of the fascia, a tubular dilator, 12-18 mm (Fig. 14.1B and C) is introduced and docked on the target level such that it is parallel to the facet joint
and directed laterally along the direction of placement of open lateral mass screws. Once the desired starting point is identified, the surface of the lateral mass is cleared of any intervening soft tissue. Illumination can be provided with a fiberoptic cable.

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