Isolated L2-L3 Lumbar Degenerative Disc Disease

Case History
The patient is a 44–year–old male with a work–related low–back injury two years prior to our evaluation. He suffered a twisting injury to his back when he fell at work, which caused immediate severe low–back pain without significant leg symptoms. He denied having prior low– back problems. His severe low–back pain, which he rated 9 out of 10, with 10 being most severe, was centered at the mid lumbar spine. This pain did not improve with conservative treatments including use of a soft lumbar corset, anti–inflammatory medicines, and several courses of physical therapy. Attempts at returning to light–duty work were unsuccessful. He was a heavy smoker, drank above average quantities of alcohol, and had workers' compensation issues pending. Physical examination revealed obesity, markedly limited lumbar flexibility, and a normal lower extremity neurological exam with no tension signs. Plain x–rays (Figs 1a, 1b) and MRI (Fig 2) demonstrated isolated L2–3 degenerative disc disease without evidence of disc herniation. The patient was very frustrated by his prior failed conservative therapy and he felt his quality of life was severely restricted by his low–back pain. He expressed a strong desire to return to some form of gainful employment.

Fig 1a	Fig 1b	Fig 2
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Questions for Consideration:
What constitutes adequate conservative care, and for what duration should conservative treatment be continued?

What further diagnostic tests are indicated;

a. if conservative treatment is continued?
b. prior to surgical treatment?

If surgical treatment is indicated, what approaches are preferred (anterior, posterior, or combined), and what is the role of instrumentation in addition to fusion?

Case Management
It was discussed with the patient due to his workers' compensation status3 and smoking history2 that the success of treating his condition either non–surgically or surgically was limited. He was advised to quit smoking, lose weight, and start vocational rehabilitation counseling. Discography was performed which demonstrated concordant pain at L2–3 with no pain responses at the lumbar disc levels.4,7 The discography pattern of the L2–3 disc revealed degeneration with a radial fissure of the annulus (Fig 3). The patient was successful with cessation of smoking for a period of six months prior to surgery. Further conservative treatment, including use of a more rigid lumbosacral corset, was unsuccessful.

It was our opinion that due to his predominance of low–back pain without radicular symptoms, an anterior lumbar discectomy would remove the pain–generating potential of the degenerated lumbar disc.1,5 Following the discectomy, an isolated anterior lumbar fusion would limit the likelihood of degeneration at the junctional lumbar levels.6 Posterior spinal fusion alone either with or without instrumentation was not advised due to his smoking history and obesity, which predisposed him to nonunion and instrumentation failure. The surgical plan presented to the patient was anterior discectomy and fusion at L2–3 using an artificial strut and iliac crest autograft. If acceptable bone quality was noted intraoperatively, then anterior instrumentation across L2–3 would be performed alone. If poor bone quality was encountered, then in addition to an artificial strut, a posterior spinal fusion with pedicular instru–mentation from L2 to L3 with an implantable bone growth stimulation device would be necessary.

The patient underwent an anterior discectomy at L2–3 and placement of an artificial strut with iliac crest bone graft, followed by anterior plate instrumentation (Fig 4a). At the four–month follow–up the patient has almost complete relief of his presurgical low–back pain.

Fig. 3	Fig. 4
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References
1. Blumenthal SL, Baker J, Dossett A, Selby DK. The role of anterior lumbar fusion for internal disc disruption. Spine. 1988;13:566–569.

2. Brown CW, Orme TJ, Richardson HD. The rate of pseudoarthrosis (surgical nonunion) in patients who are smokers and patients who are nonsmokers – a comparison study. Spine. 1986;11:942–943.

3. Franklin GM, Haug J, Heyer NJ, McKeefrey SP, Picciano JF. Outcome of lumbar fusion in Washington State worker's compensation. Spine. 1994;19:1897–1903.

4. Gibson MJ, Buckley J, Mariehinney R. Magnetic resonance imaging and discography in the diagnosis of disc degeneration. J Bone Joint Surg (Br). 1986;68:369–373.

5. Newman MH, Grinstead, GL. Anterior lumbar interbody fusion for internal disc disruption. Spine. 1992;17:831–833.

6. Penta M, Sandhu A, Fraser RD. Magnetic resonance imaging assessment of disc degeneration 10 years after anterior lumbar interbody fusion. Spine. 1995;20:743–747.

7. Wetzel FT, LaRocca SH, Lowery GL, Aprill CN. The treatment of lumbar spinal pain syndromes by discography. Spine. 1994;19:792–800.

Discussion
Isolated L2–L3 Lumbar Degenerative Disc Disease – Discussion

J. C. Le Huec, MD
Hôpital Tripode, Bordeaux, France

This case history on isolated high–lumbar back pain and disc degeneration is interesting for several reasons:

The etiology of this discopathy in a young man remains unclear. The relationship of the current degenerative changes with trauma two years previously is uncertain. As the adjacent disc levels were unremarkable with discography and MRI, I speculate that there existed a discal fragility which became decompensated when the trauma occurred. As it is unlikely that this patient will be able to return to his previous employment, job reclassification will be necessary.

The concordance of pain location with abnormalities on the diagnostic testing establishes the L2–L3 disc as the likely source of the patient's pain. The absence of radicular pain is an important element in the therapeutic decision. Dynamic x–rays performed in the sitting position can demonstrate spinal instability. Success with the use of a rigid lumbosacral corset associated with rest are essential for the diagnosis of lumbar instability. Failure of these means to relieve this patient's symptoms would indicate that instability was not a major source of pain. While discography can confirm the diagnosis in this case, the abnormal MRI findings predicted the likely source of pain. If discography is performed, the use of peridiscal anesthetic injection can be valuable to confirm the pain source.

The authors' nonoperative approach was excellent. Surgical indications were logical considering the failure of conservative treatment. The selection of the type of operative treatment will be discussed:

a. A posterior instrumented arthrodesis L2–L3 without opening the canal was one possibility. However, the stress transfer to the contiguous vertebral levels, and the fatty degeneration of the lumbar muscles with the posterior approach1,2 would certainly have facilitated a future instability of adjacent vertebral levels.

b. We would have selected anterior fixation in this case, in the absence of any radicular pain. A discectomy with discal height reconstitution by an artificial strut and plate is logical and would result in a stable mechanical construct.

c. The large surgical approach necessary for an anterior approach exposes the risks of vascular and urologic complications, and often results in a painful scar.5 For these reasons, a lateral retroperitoneal endoscopic approach, with anterior interbody fusion by cage is another good option. In this technique, anterior and posterior vertebral ligaments, as well as the abdominal musculature, are preserved. Our experience3,4 with the retroperitoneoscopic approach to the lumbar spine with artificial strut fixation has good results in terms of stability, fusion, and pain relief.

References
1. Husson JL, Poncer R, Missoury F, Lancien G, Lambotte JC, Ferte L. Modificatios histologiques de la musculature paravertebrale apres abord posterieur du rachis lombo–sacre, in "Pathologie iatrogene du rachis" by Roy Camille, Masson Ed., Paris, 1993, 298–304.

2. Kirkaldy–Willis WH, Presidential symposium on instability of the lumbar spine. Introduction, Spine, 1985, 10, 254.

3. Le Huec JC, Husson JL, Liquois F, Belliard R, Delavigne C, Le Rebeller A. Abord retroperitoneal endoscopique pour arhtodese de la colonne lombaire, Rachis, 1996, !, 161–169.

4. Le Huec JC, Husson JL, Liquois F, Delavigne C, Le Rebeller A. Retroperitoneoscopy for lumbar interbody fusion. Preliminary report of 10 cases, Comm. Eurospine Congress, Zurich, Oct. 1996, Abstract p29.

5. Loguidice VA, Johnson RG, Guyer RD. Anterior lumbar interbody fusion, Spine, 1988, 366–399.Isolated L2–L3 Lumbar Degenerative Disc Disease

Isolated L2–L3 Lumbar Degenerative Disc Disease – Discussion

Kiyoshi Kumano, MD
Kantoh Rosai Hospital, Kawasaki, Japan

This case is an example of one of the most difficult problems in the treatment of low–back disorders. The patient is an obese middle–aged man, an above–average drinker and heavy smoker, who had not worked for two years because of low–back pain. His low–back pain was the result of a fall during work, and the workers' compensation issues were still pending. Conservative treatments had evidently failed.

At this point, the primary issue to be discussed is whether surgery is indicated. I would wait until the workers' compensation issues are resolved before initiating any definitive treatment. I would not consider surgical treatment, no matter how severe the pain, until the compensation issues were resolved. Operating on the patient while the workers' compensation issues remained unsettled, would have disappointing results.

After resolving the compensation issues, I would evaluate his social and economic background, as well as his psychological state, to determine any secondary gain that might be associated with surgical treatment.2

Assuming that these issues were resolved, I would support the authors' treatment. Because of the lack of leg symptoms, the source of his low–back pain was likely either from the intervertebral discs or from the facet joints.2 Dynamic x–ray studies would be helpful to determine if retrolisthesis is present at L2–L3. Helical CT might reveal an isthmic stress fracture or spondylolysis at L2 and osteoarthritic changes at the facet joints. Discography is most valuable to determine the painful disc level in this case. Since the results of fusion of a high lumbar disc for back pain have not been satisfactory in my limited experience, and 95% of disc herniations occur at L4–L5 and L5–S1, I would perform additional discography at L5–S1 to find an occult source of his back pain. Myelography would not be necessary with these MRI findings.

I agree with the authors' recommendation of an anterior lumbar fusion instead of a posterior or posterolateral fusion at L2–L3. A complete anterior discectomy and fusion with an artificial strut and anterior instrumentation is really, in my opinion, superior to posterior implants with posterolateral spinal fusion alone. I, however, prefer circumferential fusion in this case as advocated by others.3 Anterior lumbar fusion, even when supported by spinal instrumentation may not be strong enough to withstand long–term mechanical stress for large or obese patients.

The first stage of my surgical plan would be posterior pedicle implants between L2–L3 and facet fusion with iliac crest or local bone graft. I would attempt to correct the regional loss of lordosis by using a top–loading implant system using a lever–arm technique.1 Normally there should be about 7 degrees of lordosis at L2–L3.4 This was decreased preoperatively to 0 degrees in this case. I believe that the retaining of lordosis is very important to main–tain the adjacent disc mechanics in the longterm, although there are currently no well–designed studies to demonstrate this.

The second stage would involve anterior lumbar interbody fusion with an artificial strut and iliac crest bone graft to maintain lordosis and support the internal fixation. Both of these stages can be performed on the same day, if open approaches are selected. I would delay the second operative stage for three weeks if an endoscopic anterior interbody fusion is selected. This will involve a retroperitoneal approach and the lateral placement of two artificial struts and iliac crest bone graft. This technique is much less invasive, avoiding the need for a large thoracolumbar incision in this obese patient. If osteoporotic bone is present, I would extend the posterior instrumentation from L1 to L3.

As the early results for this patient are reported as excellent, it would seem that an anterior discectomy with rigid anterior spinal instrumentation is an appropriate treatment for this workers' compensation case. I would like to congratulate the authors.