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Chapter 30 Sacropelvic Fixation Techniques

T E C H N I Q U E S

■ The Galveston L-Rod Technique ■ Placement of the Galveston rods proceeds after a standard mid- line exposure centered over the spinous processes. Here, we will focus only on those steps necessary for placement of pelvic fixa- tion. Specific steps necessary for placement of the sublaminar wires or for correction of the deformity in scoliotic or myelodys- plastic spines are beyond the scope of this chapter but can be found elsewhere. 1 ■ After placement of sublaminar wires at all spinal levels that are to be instrumented, exposure of the ilium is begun by palpating the PSIS and then dissecting off the subcutaneous tissue from the lumbosacral fascia starting in the midline and proceeding out bilaterally toward the PSIS using Cobb elevators and Bovie electrocautery. ■ The gluteal musculature should be dissected away from the outer portion of the ilium subperiosteally until the greater sciatic notch is accessible with a finger. ■ A longitudinal or oblique incision is made in the fascia overlying the PSIS.

■ A 3/16-inch stainless steel pelvic pin is then driven into the ilium toward the anterior inferior iliac spine (AIIS) to a depth of 6 to 9 cm. The starting point is just posterior to the SI joint at the level of the PSIS. Placement of a finger into the sciatic notch can help guide the pin toward the AIIS. 2 ■ The pin is left in place in order to facilitate correct bending of the L-rod, which is a 3/16-inch diameter stainless steel rod. ■ The first bend in the L-rod creates the short end, which will be placed into the table of the ilium and can be approximated by placing the short end of the rod parallel to the pelvic pin in the table of the ilium. The second bend turns the long end of the rod cephalad ( TECH FIG 1A ). ■ Next, the pelvic pin is removed, and the short end of the L-rod is driven into the table of the ilium. ■ The long end of the L-rod is then attached to the mobile spine by using the previously placed sublaminar wires ( TECH FIG 1B,C ). ■ Alternatively, some surgeons choose to attach the Galveston rod to the heads of pedicle screws.

Kyphosis

Lordosis

Side view

Top view

End-on view

A C TECH FIG 1 ● A. Appropriate shaping of the L-rod. B,C. Line diagram and model, respectively, showing proper placement of the Galveston rod into the table of the ilium. B