Introduction

Traditional treatment of low back pain from an aging spine encompasses many techniques. When surgery is contemplated, diskectomy, laminectomy, and fusion are the most common surgical procedures utilized. Diskectomy, the most common surgical procedure for sciatica and back pain, may exacerbate the back pain, especially when there is concomitant spinal instability. Chronic back pain may therefore be a consequence following surgical diskectomy. Natural progression of the degenerative process also results in lumbar spondylosis, facet arthrosis, spinal stenosis, and spondylolisthesis in the time line of an aging spine, which may also be the source of pain generation. The costs of surgical procedures to correct these conditions vary widely, depending on the surgical procedures chosen and implemented by the surgeon. Fusion, the traditional procedure for back pain, is usually recommended with caution because of its surgical morbidity and high cost. Failed back surgery syndrome (FBSS), with a paucity of effective salvage procedures, then result when surgical treatment fails. One recent study by Katz¹ estimated that the annual costs associated with all treatments of back pain in the United States are over $100 billion. This cost estimate does not even consider the difficult-to-calculate economic loss due to loss of productivity from disabling low back pain. Back surgeries to relieve back pain, however, continue to steadily increase in the United States, partly because of expansion of surgical techniques and implants used to facilitate fusion. Hazard² documented an increase in these numbers from 300,413 in 1994 to 392,948 in 2000. Though the majority of these surgeries are successful in relieving back pain, a significant percentage is not. Some studies estimate that, at best, only 60% of these surgeries are successful.^3,4 These data, along with the data reported in the Spine Outcomes Research Trial (SPORT),⁵ demonstrate that although most spine surgeries are cost-effective, even the 2-year results for degenerative spondylolisthesis, the premier indication for one-level fusion, is questioned. With good patient selection, accurate diagnostic criteria, and a low cost, a minimally invasive surgical option, addressing just the innervation of the facet-mediated pain generator, may be a viable minimally invasive procedure to be considered before the definitive surgical fusion or joint replacement option is considered.

The Yeung Endoscopic Spine Surgery (YESS) decompressive approach, described in Chapter 64, details a transforaminal endoscopic approach that utilizes a minimally invasive surgical technique enabling disc and foraminal decompression as well as ablation of painful nerves and removal of chemical mediators in the disc, annulus, and foramen. Presumed primary sensory nerves innervating the disc and facet can be ablated, and pathologic conditions causing inflammation (and, therefore, pain) are addressed. The technique, expanded to target denervation of the branches of the dorsal ramus responsible for facet mediated pain, is the subject of this chapter.

Lumbar spondylolysis, facet arthrosis, spondylolisthesis, both isthmic and degenerative, that may also be associated with spinal stenosis, are traditionally treated with open decompression, dynamic stabilization, or fusion. A recent article by Weinstein et al,⁵ examining the data from the SPORT trial, concluded that degenerative spondylolisthesis surgery (decompression and fusion) is not a cost-effective procedure when examined over a 2-year period. These data highlight the need to better evaluate back pain patients with more specific diagnostic procedures, such as evocative diskography, selective nerve root blocks, foraminal epidural steroids, and facet and medial branch blocks. The information obtained from these procedures in experienced hands allows the surgeon to more selectively choose who might benefit from surgical intervention. Many of the pain generators can also be addressed earlier in the disease process if surgery does not cause significant paradoxical effect on the aging spine. In this chapter we outline a technique for performing endoscopic medial, intermediate, and lateral branch rhizotomy arising from the dorsal ramus, a sensory branch from the origin of the main spinal nerve, that we have termed, dorsal endoscopic rhizotomy.

The endoscopic applications outlined in this chapter are therefore applicable to all painful conditions arising from the facet joint complex.

Indications and Contraindications

Endoscopic rhizotomy has been performed successfully, and remains effective at over 3-year follow-up in most patients in our pilot study. It is appropriate for the following conditions causing axial back pain.

Ideal Indications

Patients who will most likely benefit from selective endoscopic rhizotomy include the following:

1. Axial back pain solely from arthropathy of the lumbar facet joints without leg pain: The diagnostic imaging of these patients may present with narrowing disc space, but the discogenic contribution to back pain is thought to be a minor contributor. These patients are usually not debilitated, but the patients’ pain significantly affects their activities of daily living (Figure 65-1A-C).

2. Axial back pain mostly from facet arthrosis with very mild buttock and thigh pain: Pain is approximately 90% in the back and 10% in the leg.

3. Subacute and chronic axial back pain following a posttraumatic injury to the facet joints refractory to nonsurgical treatment.

4. Axial back pain from adjacent disc level of fusion demonstrating spondylosis and facet arthrosis causing pain without disc segment instability.

5. All of the previously mentioned patients should have more than 80% pain relief after controlled diagnostic and therapeutic medial branch block (MBB).

FIGURE 65-1a, 1b, 1c Ideal patient with single level facet arthrosis and chronic, non-debilitating axial back pain.