Minimally Invasive TLIF for the Treatment of Radiculopathy

This surgeon is a consultant of Medtronic, but received no compensation for this case discussion.

History

The patient is a 40-year-old male with a 2 year history of right L5 radiculopathy and mild low back pain.  Recently, his symptoms have become progressive. He has seen two other surgeons for these issues.

Examination

The patient is of average height and weight. He does not smoke.

There is mild right extensor hallucis longus weakness. Positive right straight leg raise to 60-degrees. Hypalgesia in the dorsum of the right foot.

Prior Treatment

Injections no longer effectively relieve symptoms. However, a L5 selective nerve root block did provide temporary relief. Despite non-steroidal anti-inflammatory drugs, pain medications, organized physical therapy, and injections, the patient's symptoms progress.

Pre-treatment Images

The MR imaging demonstrates a Grade 1 spondylolisthesis and central disc herniation (Fig. 1A) and foraminal stenosis and L5 nerve root impingement (Fig. 1B).

Figure 1A. Mid-line sagittal MRI

Figure 1B. View of the foramen

Figure 1C. Axial view

Diagnosis

Spondylolisthesis with L5 nerve root impingement

Selected Treatment

Minimally invasive Transforaminal Lumbar Interbody Fusion (TLIF) with CD HORIZON® SEXTANT® II System to decompress the exiting nerve root and realign the spine.

Through small skin incisions, the METRx® System’s muscle-splitting dilator tubes separate muscle to access the lumbar spine. The CD HORIZON® SEXTANT® II System delivers the screws and rods through the skin incisions.

This procedure allows direct visualization of the nerve root. O-ARM® Surgical Imaging System allows for a three-dimensional view of the patient's anatomy without the need for live fluoroscopy. Visualization is improved. There is no radiation exposure to the surgical team and some exposure to the patient.

Figure 2A.  Patient positioning

Figure 2B. Finding the posterior sacroiliac spine

Figure 2C. Placing the percutaneous hip pin

Figure 2D. Reference arc placed

Figure 2E. Image obtained using O-ARM® Surgical Imaging System

Intra-operative photography with O-ARM® Surgical Imaging System. The imaging compares the O-ARM® System CT* trajectory views (top; left and right) and similar fluoroscopic images (bottom; left and right).

Figure 2F. Navigation used to plan trajectory and incision

Figure 2G. Placing the awl tap

Figure 2H. Placing the guide wire

L5 screw placement (Figs. 2I, 2J)

Figure 2I	Figure 2J

Sacral screw placement (Figs. 2K, 2L)

Figure 2K	Figure 2L

Tapping ipsilateral screw holes; intra-operative photo (Fig. 2M) and O-ARM® System multidimensional images (Fig. 2N).

Figure 2M	Figure 2N

Intra-operative images demonstrate use of the METRx® System and CD HORIZON® SEXTANT® II System Reduction Instrument Set (Figs. 2O-2BC)

Figure 2O. Finding the facet joint through the first dilator	Figure 2P. Dock tube for TLIF

Figure 2R. View of the facet joint	Figure 2S. Working through the tube

Figure 2T. Harvesting local autograft	Figure 2U. Camben's triangle

Figure 2V. CAPSTONE® PEEK interbody placement	Figure 2W. Ipsilateral screw placement

Figure 2X. Creating paths for the rods	Figure 2Z. Measuring rod length

Figure 2AB. Passing the rods	Figure 2BB. Checking rod length using fluoroscopy

Figure 2CB. Reduce, compress, and set screw

Post-operative skin incisions (Figs. 3A, 3B)

Figure 3A	Figure 3B

Medtronic Technology Featured
O-ARM® Surgical Imaging System
METRx® System
CD HORIZON® SEXTANT® II System Reduction Instrument Set

Outcome

At one month post-op the patient experienced mild to moderate incision pain.  At 2 months, mild back pain required no medications.  The patient is progressing well, is back to work, not taking narcotics, and his radiculopathy has resolved.

Note to patients
As you read this please keep in mind that all treatment and outcome results are specific to the individual patient. Results may vary. There are some risks associated with minimally invasive spine surgery, including transitioning to a conventional open procedure, neurological damage, damage to the surrounding soft tissue, and instrument malfunction such as bending, fragmentation, loosening, and/or breakage (whole or partial). Please consult your physician for a complete list of indications, warnings, precautions, adverse events, clinical results, and other important medical information.

This therapy is not for everyone.  Please consult your physician. A prescription is required.  For further information, please call MEDTRONIC at (800)876-3133.

Case Discussion

Lali Sekhon, MD, PhD, FACS, FAANS

Neurosurgeon

Nevada Neurosurgery

This is an interesting case showing the application of multiple medical technologies to manage radiculopathy and low back pain refractory to conservative treatment. As the author outlines, there are several treatment options here including a simple decompression, anterior procedures and open procedures. The pathway selected by the author led to a satisfactory surgical result.

The case opens a veritable Pandora’s Box of when and if new technologies should be used. A recent review article on minimally invasive surgery suggests equivalent but not superior results to open surgery¹ and I suspect  outcome depends as much on surgeon experience and patient selection as it does on the type of procedure selected.

It is difficult to directly decompress an exiting nerve root without destabilizing the facet joint, so the instrumented fusion seems a logical accompaniment. An anterior procedure to increase foraminal height may have achieved the same result. The facets did not look bad and, in some surgeons’ hands, an arthroplasty may have been an option even in the face of the spondylolisthesis.

The addition of the O-ARM® opens a fascinating new chapter in spinal navigation. The O-ARM® seems to have taken away some of the registration pain of previous navigation systems and allows for an updated CT* to be reconstructed during surgery.  This allows for visualization of hardware at the end of a case via CT*; something not previously available.

The other obvious gain for a percutaneous procedure is the reduced radiation exposure to the surgeon. This gain must be weighed against the considerable capital expenditure to acquire new technologies. It would be interesting to know how long the procedure took from the time the patient was turned prone until the patient was placed back in the hospital gurney. Whether its use gives superior results and affects patient outcome remains to be seen. In short, the author is to be congratulated on an excellent outcome in this patient using the latest cutting edge technologies.

Reference
1. Fourney DR, Dettori JR, Norvell DC, Dekutoski MB.  Does Minimal Access Tubular Assisted Spine Surgery Increase or Decrease Complications in Spinal Decompression or Fusion? Spine 2010;35:S57–S65.

Author's Response

Jean-Pierre Mobasser, MD

Neurosurgeon

Goodman Campbell Brain & Spine

Thank you, Dr. Sekhon for taking the time to review the case. 

I agree with Dr. Sekhon that patient selection is critical to patient outcome.  The type of surgery chosen is secondary.  The O-ARM® Surgical Imaging System is a critical instrument for use during minimally invasive spine (MIS) surgery.  These procedures now can be performed without radiation exposure to the surgeon.  Previous to the O-ARM® Surgical Imaging System, the amount of radiation exposure was extremely high and kept many surgeons from adopting minimally invasive techniques.  The ability to see an axial view, while placing instrumentation is a huge leap forward for spine surgery. 

There have been several studies to show superior minimally invasive outcomes versus open spine surgery; but, these mainly compare against historical controls.  Doctors Raja Rampersaud and Steven Glassman have collected multi-center retrospective data to compare minimally invasive versus open lumbar fusion patients for spondylolisthesis, and two-year data shows more favorable outcomes in the minimally invasive patient group.  Clearly, a prospective study comparing MIS versus open lumbar fusion would be very valuable addition to the existing spine literature.

In response to Dr. Sekhon’s question of duration of the case, we measure “skin to skin” time and, for the average minimally invasive transforaminal lumbar interbody fusion (TLIF) with navigation, the procedure takes approximately 2-½ hrs.  Our experience shows that navigation now saves time rather than adds time to the case.

*The O-arm® is cleared by the US FDA as a Mobile X-ray System under 21 CFR 892.1720. Medtronic Navigation makes no claim that the O-arm® complies with the necessary performance standards to be called a Computed Tomography X-Ray System under 21 CFR 892.1750.

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