Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Summary

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

Abstract

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

Introduction

The TLIF is one of several options available when considering interbody fusion for degenerative disc disease and spondylolisthesis. The TLIF technique was initially developed in response to complications associated with the more traditional posterior lumbar interbody fusion (PLIF) approach. More specifically, the TLIF minimized retraction of neural elements, thereby reducing the risk of nerve root injury as well as the risk of dural tears, which can lead to persistent cerebrospinal fluid leak. As a unilateral approach, the TLIF technique also affords better preservation of the normal anatomy of the posterior elements¹. The TLIF can be performed....

Protocol

All procedures and research activities were performed with institutional review board approval (CHR #17-21909).

1. Pre-operative Preparation

1. Induce general anesthesia in the patient, and position the patient prone on the Jackson table with chest bolster and hip pads.
2. Prep and drape the patient's back in the usual sterile fashion.

2. Surgical Procedure

1. Make a small stab incision using a #15-blade over the PSIS contralateral to the side of the planned TLIF.
2. Place a biopsy needle through the stab incision into the ilium to harvest bone marrow aspirate (

Results

Fifty patients underwent surgery with this technique under a single surgeon (AC). The average age was 53 years (range 29-84 years) with 30 women and 20 men. Patients presented with the following pathology: spinal stenosis (n=45), spondylolisthesis (n=29), facet cysts (n=5), degenerative scoliosis (n=3), and cauda equina syndrome (n=1). Symptoms were back and leg pain in 42 cases, back pain alone in 2 cases, and lower extremity radiculopathy in 6 cases. In 10 cases, patients had undergone .......

Discussion

There are several critical steps to the procedure described. The first critical step is the process of registration. The reference arc must be placed in solid bone and should be oriented appropriately to avoid interfering with the S1 pedicle screw placement if needed. The second critical step is maintaining accuracy of the navigation after an intraoperative CT scan is performed, which can be done by identifying normal anatomic structures and confirming the correct positioning. The accuracy should be periodically verified.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
O-arm intraoperative CT	Medtronic, Minneapolis, MN
Stealth Navigation System	Medtronic, Minneapolis, MN
Jamshidi Needles			for bone marrow biopsy
Cefazolin			antibiotic.
Vicryl Sutures
Steri-Strips			for skin closure
Telfa dressing
Tegaderm			for dressing
Jackson table
15-blade
High-speed bone drill
Tubular dilator
K-wires
Reduction towers
TLIF retractor
2 or 3 mm Kerrison rongeur
Woodson elevator
Disc shaver and distractor
Fluoroscopy
Allograft cellular bone matrix
Interbody cage
Rod
Soft lumbar brace
X-ray
Patient-controlled analgesia pump