The Deformity TLIF: Bilateral Facetectomy and Osteotomy Closure with a Hinged Table

Abstract

Background:

Increasing emphasis has been placed on segmental lordosis correction, even in short segment constructs. However, the majority of reports on TLIF indicate that lordosis correction is modest at best. TLIF with bilateral facetecomy has been described with better lordosis correction, but is usually performed with the spine in extension throughout the case. This report presents a new technique for lordosis correction during TLIF with the use of bilateral facetectomy and osteotomy closure using a mechanically hinged operative table.

Methods:

A 78-year-old male presented with claudicatory back and leg pain due to foraminal stenosis and spondylolisthesis at L4-5 and L5-S1, and was operated on with bilateral facetectomies and TLIF while positioned on a motorized-hinged table, which started in flexion for the decompression and was brought into extension at the end of the case for osteotomy closure.

Results:

Segmental lordosis from L4-S1 increased from 15° pre-operatively to 42° postoperatively.

Conclusions:

A comparison of pre- and post-operative lateral radiographs showed 27° segmental lordosis correction, and intra-operative fluoroscopy showed correlation between extension of the table and segmental lordosis correction. Bilateral facetectomy and TLIF allows for segmental lordosis correction. Use of the hinged table allowed for ideal positioning during the decompression and controlled osteotomy closure with close correlation between table position and segmental alignment.

Level of Evidence: V

Introduction

Short segment kyphosis increases the amount of lordosis required at adjacent segments. This adjacent hyperex-tension compensates for a short time, but as the adjacent segment deteriorates the effect is lost and global imbalance can subsequently occur.¹ Thus, lordosis correction has been emphasized even in short segment constructs.²

TLIF with bilateral facetectomy (Smith-Peterson osteotomy, SPO) is a well-described technique for lordosis correction,³ but the procedure is usually performed with the spine in extension.^4,5 This position narrows the canal diameter,⁶ which makes the decompression more challenging and may limit the size of the interbody that can be placed.

Here, we report a new TLIF technique combined with SPO using a mechanically hinged table. The technique starts with the table in flexion to facilitate the decompression, and ends with controlled osteotomy closure through the mechanical hinge, with close correlation between table position and intra-operative segmental alignment.

Methods

Case Report

This experimental protocol and was approved by our institution’s accredited Institutional Review Board, which allowed for review of interbody fusions with an osteotomy that were presented in a de-identified fashion. The IRB did not require individual patient consents for retrospective presentation of de-identified data. A 78-year-old male presented with progressively worsening claudicatory back and leg pain. Imaging revealed spondylolisthesis at L4-5 and spondylosis at L5-S1 with foraminal stenosis at both levels (Figures 1 and 2). After failure of non-operative management, he proceeded to surgery.

Figure 1.

Pre-operative standing radiographs showing L4-5 spondylolisthesis and L5-S1 spondylosis.

Figure 2.

Mid-sagittal and both left and right para-sagittal T2 MRI images showing foraminal stenosis at L5-S1 and L4-5.

Surgical Technique

The patient was placed prone on a hinged table (Pro-Axis^® Spinal Surgery Table, Mizuho OSI, Union City, CA). The table was then flexed to 10° and brought into reverse-trendelenburg to level the spine. Sub-periosteal exposure was performed out over the facet joints just enough to expose screw start points. Pedicle screws were then placed in the standard fashion (Figure 3A). The interspinous ligament was removed and a laminar spreader was used to distract the spinous processes. If the spinous process is absent or broken, then pedicle-based distraction is used. The bilateral inferior articular processes were removed with an osteotome. A curved curette was used to define the lateral border of the superior articular process (SAP) and the bone was removed outside-in with a combination of the rongeur and the kerrison. Bone removal continued medially until the traversing nerve root was visible and bleeding was controlled with bipolar electrocautery. Disc space prep proceeded with pituitary and currettes, followed by the turn-and-rotate distractors to serially dilate the disc space (Figure 3B). The SAP was removed on the contralateral side, thus completing the SPO, and contralateral disc prep was performed. A trial was used to select the appropriately sized cage. The disc space was irrigated and packed with local autograft from the facetectomies. 2-3 cc of bone can usually be inserted. An appropriate sized bulleted TLIF cage was then inserted (Figure 3C). The distractor was then removed from the contralateral side, further bone graft impacted, and a second cage inserted. Fluoroscopy was obtained to verify the cage position. Any remaining midline flavum was then removed with a kerrison to complete the decompression, but the lamina was preserved.

Figure 3.

Performance of bilateral TLIF. (A) Pedicle screws are placed in the standard fashion. (B) After completion of the osteotomy, the disc space is prepared and turn-and-rotated distractors are used to serially dilate the disc space. The trial is used to select an appropriate height cage. (C) After cage insertion, fluoroscopy is obtained to verify cage position.

The hinged table was then brought into extension in 5° increments until it reached a total of 10° extension (Figure 4). Rods and set screws were placed and compression across the pedicle screws was used to further increase lordosis (Figure 5). The midline lamina was then decorticated and packed with a mixture of allograft and the remaining autograft bone.

Figure 4.

Serial osteotomy closure with the hinged table.

Figure 5.

Standing post-operative AP and lateral radiographs showing improved segmental and global alignment.

Results

Based on comparison of pre- and post-operative lateral radiographs, segmental lordosis from L4 S1 increased from 15° pre-operatively to 42° post-operatively, for a total of 27 segmental lordosis correction. Intra operative fluoroscopy showed close correlation between extension of the table and segmental lordosis correction alignment.

Discussion

TLIF with SPO is a well described technique for segmental lordosis correction.³ Here, we describe the first report of positioning on a motorized hinged table, which carries several advantages. First, the table starts in a flexed position, which allows for optimal visualization during the decompression. Further, this positioning facilitates segmental distraction during the TLIF which allows for larger cages to be inserted. Second, because the interspace is distracted, very little midline lamina needs to be removed to complete the decompression, which allows for A midline bony fusion, and avoids the need for wide lateral gutter dissection/grafting with its associated muscle trauma. Third, the canal is not entered until after it has already been widely distracted by cage insertion, which helps minimize dural tear risk. Lastly, substantial lordosis correction is possible. 16-18 mm high cages with 18° of lordosis can be routinely inserted, and intra-operative table extension allows for controlled osteotomy closure. In this case, 27° segmental lordosis was achieved across the two operative levels (Figure 6), which compares favorably against prior literature reports for TLIF.^7-10

Figure 6.

Comparison of pre- and post-operative lateral radiographs showing 27° segmental lordosis correction.

Conclusion

TLIF with bilateral facetecomy on a motorized-hinged-table allows the surgeon to perform the decompression and TLIF with the spine in flexion and the disc space distracted, which is an ideal situation. Closure of the osteotomy through the mechanical hinge in the table allows for substantial lordosis correction.