Contraindications
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Previous surgical procedures that involved the presacral space resulting in fibrosis in this space, then rendering the rectum immobile and scarred to the anterior sacrum
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History of perirectal abscess
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Severe chronic inflammatory bowel disease
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History of pelvic radiation
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Current pregnancy
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Anomalous iliac vessels in the presacral space evaluated by magnetic resonance imaging (MRI) or computed tomography (CT) angiography
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Abnormally accentuated sacral curve that would necessitate an impossible trajectory for targeting and placement of the rod for L-5-S1 or L4-5-S1 levels (all potential patients should undergo a preoperative evaluation to assess trajectory by a lateral, standing x-ray of the lumbar spine, entire sacrum, and coccyx)
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History of pilonidal cyst or hysterectomy—not contraindications
Planning and positioning
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The trajectory for the procedure is evaluated with x-rays and MRI before scheduling the procedure.
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MRI or CT angiography of the presacral space is performed to evaluate for vascular anomalies or other pathology (e.g., tumor) before scheduling the surgery.
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The patient begins a clear liquid diet at noon the day before surgery and completes a bowel preparation later that day.
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The patient is positioned prone.
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Lordosis must be maintained or accentuated by placement of bolsters under the hips, thighs, or knees. Lordosis curve is checked with fluoroscopy.
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Legs must be fully abducted on the table or spine frame, specifically required for initial portion of the procedure.
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An occlusive barrier is placed just above the rectal sphincter (facilitated by placing 3-inch tape on each buttock; other end of the tape is secured laterally to the table, then retracting each buttock).
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A Foley catheter placed in the rectum permits injection of air to define clearly the distal portion of the rectum and its relationship to the sacrum.
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Although two fluoroscopy units are preferable, the procedure can be performed with a single fluoroscopy unit.
Figure 85-1:
Lumbar interbody fusion using TranS1 (Wilmington, NC) instrumentation. A, Typical sacrum and trajectory for the TranS1 (Wilmington, NC) approach. The rectum and presacral space are easily seen. B, Optimal zone for placement of the axial rod and entry point relative to the sacrococcygeal ligament and coccyx. C, In this example, a TranS1 (Wilmington, NC) procedure is contraindicated because the sacral curve would create a trajectory that could cause axial rod placement in the spinal canal.
Figure 85-2:
Preoperative templating for trajectory. A, CT scan is used to map the trajectory for a one-level procedure. B, Standing lateral x-ray is preferred to map the two-level procedure because it shows the patient’s preoperative lordosis. C, Placement of the two-level axial rod.
Figure 85-3:
Operating room setup for TranS1. A, The patient is positioned prone, with the buttocks and legs abducted. After the buttocks are retracted and secured with tape, a Foley catheter is placed in the rectum. B, Lateral fluoroscopy of the presacral space and the bowel after air is injected into the rectum. C, The occlusive drape is placed above the rectal sphincter. D, Two fluoroscopy units are positioned for the procedure in the lateral and anteroposterior planes.
Procedure
