Dorsal paddle leads implant for spinal cord stimulation through laminotomy with midline structures preservation

Abstract

Background: Pain relief obtained with spinal cord stimulation (SCS) in failed back surgery syndrome (FBSS) has been shown to be more effective with paddle leads than with percutaneous catheters. A laminectomy is generally required to implant the paddles, but the surgical approach may lead to iatrogenic spinal instability in flexion. In contrast, clinical and experimental data showed that a laminotomy performed through flavectomy and minimal resection of inferior and superior lamina with preservation of the midline ligamentous structures allowed to prevent iatrogenic instability. Aim of the study was to assess degree of instability and pain level in patients operated for SCS through laminectomy or laminotomy with midline structures integrity. The surgical technique is described and our preliminary results are discussed.

Methods: Nineteen patients with FBSS underwent SCS, 12 through laminectomy and 7 through uni- or bilateral interlaminotomy with supraspinous ligament preservation. Postoperative local pain was evaluated at 15, 30, and 60 days. Static and dynamic X-rays were performed after 2 months.

Results: The techniques allowed implanting the paddle leads in all cases. No intraoperative complications occurred. Local pain was higher and recovery time was longer in patients with laminectomy. We did not observe radiological signs of postoperative iatrogenic vertebral instability. Nevertheless, two patients who underwent laminectomy showed persistence of local pain after 2 months probably due to pathologic compensatory stability provided by the paraspinal musculature.

Conclusions: The laminotomy is a minimally invasive approach that ensures rapid recovery after surgery, spinal functional integrity, and complete reversibility. Further studies are needed to confirm our preliminary results.

Keywords: Failed back surgery syndrome; laminotomy; paddle lead; spinal cord stimulation minimally invasive technique.

Figure 1

(a-b) Monolateral interlaminotomy with dura mater exposed (white arrow). Supraspinous ligament structures are preserved (white star). Controlateral extension of the exposure under the midline ligamentous structures (blue star), (c) Lead blank insertion through the interlaminotomy, (d) Lead paddle insertion through the interlaminotomy

Figure 2

(a) A-P view of postoperative X-ray show a 4 + 4 surgical lead placement at T8-T9, (b) The L-L view of the dynamic X-ray in flexed position does not show any sign of vertebral instability

Figure 3

Bilateral interlaminotomy performed at T10-T11 for a 5 + 6 + 5 surgical lead insertion. The supraspinous ligament is intact (white star). The two cables of the lead paddle (white arrows) coming out from the spinal canal on both sides are fixed to the spinous process (blue arrow)

Figure 4

L-L and A-P view of postoperative CT scan show the 5 + 6 + 5 surgical lead placement at T8-T9 in the same case described in Figure 3. The lead is correctly aligned with the median line

Figure 5

3-D postoperative CT scan of the same case described in Figure 3. The two cables of the lead paddle coming out from the spinal canal on both sides of the spinous process are shown

Figure 6

Surgical-related pain after 15, 30, and 60 days in patients operated through interlaminotomy (a) and laminectomy (b)