Fusion or Arthroplasty for a Symptomatic Degenerative Disc?

Guest Discussants: 

Case Presentation
AThis case involves a 41-year-old man with a 15-year history of low back pain. His pain increased about two years ago and, since then, has gradually worsened and increasingly affected his daily activities. He has no radiculitis, only axial pain that worsens with activities. He’s had over eight months of physical therapy and is seeking a surgical solution. He has had discography which revealed concordant pain at L5-S1 and no pain at the L4-5 and L3-4
control levels. He’s read a lot about fusion and disc arthroplasty and is interested in one of the two options. 

  What would you recommend?  


Figure 1. AP radiograph of the lumbar spine. (left)         
Figure 2. Lateral radiograph of the lumbar spine showing narrowing of the disc space at L5-S1. (right)

Figure 4. Axial MRI of the L5-S1 disc space showing a small central bulge without significant neurological compression.

Figure 5. Radiograph of discography showing some leakage of the injected dye at L5-S1.

Figures 6 & 7. Post discograph CT scan showing injected dye contained within the nucleus of
the discs at L3-4 and L4-5, with diffusion of the dye at L5-S1.

    


Richard D. Guyer, MD, Responds
While this patient appears to be an ideal candidate for disc replacement, certain factors need to be clarified. His case summary indicates that he failed conservative treatment. With his 15-year history of chronic back pain that apparently worsened 2.5 years ago, it is important to establish that he indeed had the proper medical and interventional (MI) care which would include core stabilization exercises, patient education, proper anti-inflammatory medications and injections. I will assume that he has had all the appropriate MI treatment.

The patient’s MRI shows a dehydrated L5-S1 disc with a herniation (Figure 3). The patient did not have radicular pain, so it is doubtful that the herniation is a significant factor in his symptoms. Considering his MRI findings and the chronicity of his pain, the next step is discography. The discogram was positive at the L5-S1 level, confirming the findings of the MRI scan (Figures 6 & 7). Although no information was provided concerning the pain intensity experienced during the discogram or the injection pressures, I will assume that the pain level provoked was at least 6 out of 10 without extremely high injection  pressure. The fact that the two levels above the suspected L5-S1 disc were both painless further supports single-level pathology and the reliability of the pain provocation portion of the discogram.1

The next factor to consider is the condition of the facet joints. While we can’t see the facet joints well on the MRI scan,
they do not show significant facet abnormality. (Figure 4) On this patient’s CT discogram, we can better evaluate facet joint integrity. The post-discography CT also confirms that discs have been injected in their center as opposed to the often seen intra-annular injection. This may produce an unreliable positive pain response, invalidating the pain provocation evaluation. If the CT-discogram raises concerns about their condition, facet injections at the L5-S1 level would help determine whether these structures were contributing to the patient’s pain. If the facet injection indicates a significant symptom contribution, TDR should not be considered.

The patient’s psychological state must also be considered. If the patient is taking chronic narcotics and if he is not working, we routinely recommend behavioral medicine evaluation.2 We have found psychosocial screening valuable specifically in disc replacement patients where a significant relationship to clinical outcomes could be demonstrated.3

Comorbidities to consider in potential disc replacement patients include bone density, fracture, tumor, >grade I spondylolisthesis and morbid obesity.4 Given the age and gender of this patient, DEXA scanning for osteopenia would not be ordered routinely unless something in his history suggests metabolic problems. Among the concerns in obese patients is the ability to achieve adequate retroperitoneal access to the disc space to properly place the TDR.

For this individual, TDR offers a number of advantages including faster rehabilitation. Most patients require only an
overnight stay and are able to return to driving and light duty work within one to two weeks. Two to six weeks postop, he would begin therapy and gradually resume normal activities. At six to twelve weeks, he would progress to carrying out near normal activities restricted during this time only to avoiding full extension. It is during this time that osseous ingrowth is occurring in the device end plates and there is scar formation in the anterior aspect of the anterior disc space. With the exception of restrictions on extension, post-TDR rehabilitation is very similar of that of a microdiscectomy.

Economic data show that the cost of doing disc replacement is far less than the typical anterior posterior fusion or TLIF with or without the use of available growth factors.5-7 The five–year data for both Charité and ProDisc show lower rates of revision surgery when compared with fusion controls. These patients also have a greater rate of employment and lesser rate of disability.8  European data support good long-term outcome following disc replacement.9,10

Overall, I think this patient appears to be an appropriate candidate and I recommend a lumbar disc replacement as my preferred treatment over a spinal fusion.

References
1. Block AR, Vanharanta H, Ohnmeiss DD, Guyer RD. Discographic pain report. Influence of psychological factors. Spine. 1996;21:334-338.

2. Block AR, Ohnmeiss DD, Guyer RD, Rashbaum RF, Hochschuler SH. The use of presurgical psychological screening to predict the outcome of spine surgery. Spine J. 2001;1:274-282.

3. Block A, Austin S, Ohnmeiss D. Presurgical psychological screening in total disc replacement: SCL-90 profiles. Proceedings of the 23rd Annual Meeting of the North American Spine Society. Spine J. 2008;8(5S):73S.

4. Blumenthal S, McAfee PC, Guyer RD, et al. A prospective, randomized, multicenter Food and Drug Administration investigational device exemptions study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: part I: evaluation of clinical outcomes. Spine. 2005;30:1565-1575.

5. Levin DA, Bendo JA, Quirno M, et al. Comparative charge analysis of one- and two-level lumbar total disc arthroplasty versus circumferential lumbar fusion. Spine. 2007;32:2905-2909.

6. Guyer RD, Tromanhauser SG, Regan JJ. An economic model of one-level lumbar arthroplasty versus fusion. Spine J. 2007;7:558-562.

7. Patel VV, Estes S, Lindley EM, Burger E. Lumbar spinal fusion versus anterior lumbar disc replacement: the financial implications. J Spinal Disord Tech. 2008;21:473-476.

8. Guyer RD, McAfee PC, Banco RJ, et al. Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the Charité artificial disc versus lumbar fusion: five-year follow-up. Spine J. 2009;9:374-386.

9. David T. Long-term results of one-level lumbar arthroplasty: minimum 10-year follow-up of the Charité artificial disc in 106 patients. Spine. 2007;32:661-666.

10. Lemaire JP, Carrier H, Ali E-HS, Skalli W, Lavaste F. Clinical and radiological outcomes with the Charité artificial disc: a 10-year minimum follow-up. J Spinal Disord Tech. 2005;18:353-359.

Louis G. Jenis, MD, Responds
This case illustrates a problem all spine practitioners encounter, the middle-aged patient with a history of chronic low back pain (CLBP). This 41-year-old male presents with an extended history of low back pain. Radiographic assessment reveals moderate disc space narrowing at the L5-S1 segment with loss of segmental lordosis. The accompanying MRI scan (Figures 3 & 4) confirms L5-S1 disc dehydration, collapse and mild central disc bulging without spondylolysis, spondylolisthesis or significant Modic changes. Of note, the L5-S1 facet joints are free of significant effusion or arthropathy. Provocative discography provides a “positive” result at L5-S1 consistent with a concordant pain response and no pain reproduction at L3-4 or L4-5. (Figure 5) The post-discography CT images (Figures 6 & 7) also confirm the presence of anatomical degeneration at L5-S1. The patient is now interested in discussing options for surgical intervention.

Surgery for CLBP remains controversial due to variable clinical results and unclear indications. Today, however, arthrodesis remains the preferred surgical modality for CLBP from a painful motion segment recalcitrant to conservative treatment. Conceptually, understand that not all segmental pain is “discogenic.” The facets, instability and other factors may contribute to nocioception. To document the effects of fusion, the literature contains many clinical and radiographic outcomes studies. These studies differ by study design, surgical indications and techniques. Chou et al, in a systematic review of the literature, identified 18 randomized trials evaluating the outcomes of surgery for lumbar DDD.1 Among these studies, four level I RCTs comparing fusion versus conservative treatment have been published, two of which enrolled more than 100 patients. In an often quoted study, Fritzell et al evaluated the role of lumbar fusion in a prospective, randomized clinical trial.2 The results published from the Swedish Lumbar Spine Study Group included two-year follow-up of 294 patients from 19 centers. Patients were randomized into a conservative treatment arm or one of three surgical arms including posterolateral noninstrumented fusion, instrumented PLIF or circumferential fusion. The results, although not blinded, represent the first level I evidence that surgically-treated patients experienced significantly greater improvement in ODI, satisfaction scales and return to work.

This and numerous other studies indicate that patients with recalcitrant segmental lumbar pain clearly benefit from fusion through reductions in pain and disability. The ideal fusion technique remains controversial. Advocates of interbody fusion claim significant advantages over a posterolateral approach including more favorable biomechanical environment, greater vascularity and surface area for graft incorporation, and better restoration of sagittal and coronal plane alignment. Although interbody approaches may confer higher fusion rates, studies also reveal higher complication rates. Therefore, balance the decision to perform an ALIF or PLIF/TLIF with the patient’s demand level. Consider interbody approaches in patients with single level DDD, greater than 50% disc space collapse, segmental  kyphosis or risk factors for a nonunion (diabetic, smoker, previous nonunion, etc). The patient we are considering would be best managed with an interbody fusion and I would recommend an ALIF procedure with stand-alone fixation.

Given our extensive experience and knowledge with fusion techniques, why would anyone recommend a TDR in this patient? TDR proponents cite several intuitive attractive features including “better pain relief” and “restoration of motion at the index level of surgery or at adjacent segments of the lumbar spine.” The problem is that the current evidence does not support any of these contentions.

The first level I data comparing the outcomes of Charite TDR and fusion were reported by Blumenthal et al3 as a noninferiority study. At baseline, there were no significant differences between the 205 patients in the experimental arm (TDR) and 99 patients in the control (fusion) arm. There were no differences in operative time, blood loss or levels of surgery between the groups. At 24 months, the visual anlaog scale (VAS) score reduction compared to preoperatively was 40.6 in the TDR group and 34.1 in the fusion group, and the ODI change was 48.5% and 42.4% respectively. The differences between groups were not statistically significant. A level II study recently published by Guyer et al4 is the first long–term five year RCT comparing the two procedures. Though limited by dropout rate, the study does provide some evidence of equivalent clinical outcomes. When considering other level III longer–term follow-up studies,5,6 it is fair to conclude that a well-indicated and technically well-performed TDR offers pain and functional improvement comparable to fusion.

A key phrase is “when performed technically well.” TDR remains a technically demanding procedure and requires a wider anatomical exposure of the disc space. In that TDR outcomes are more likely than ALIF to be compromised by suboptimal positioning, more precise insertion is required. In the Charité IDE, nearly 17% of devices were placed in a less than ideal position and resulted in poorer clinical outcomes.7 Therefore, considering only clinical outcomes, the best available evidence suggests that TDR may be considered as an alternative to fusion but certainly does not offer superior results.

The literature reporting adjacent segment degeneration (ASD) rates following TDR or fusion is limited to retrospective reviews and case reports. Only a few available level III and IV data suggest that the incidence of asymptomatic and symptomatic ASD may be greater in patients undergoing fusion.5,6 To date, no level I data have established a role for TDR in limiting or preventing ASD. In a study following ALIF patients for 20 years, Wai et al8 confirmed that, while 74% of patients developed MRI evidence of degeneration in the remaining lumbar discs, 23% showed changes isolated to the adjacent level to the fusion and 18% had changes other than at a normal adjacent level. The authors concluded that degenerative changes were less likely related to the biomechanical limitations of fusion as opposed to unique
patient characteristics and constitutional factors.

Understanding the role of the facet joints in segmental pain remains complex. Van Ooij identified facet joint dysfunction as a cause of TDR failure in 11 of 27 patients who required a posterior fusion for salvage.9 As our understanding of these devices evolves, the list of contraindications to TDR continues to grow. In two separate studies, the incidence of contraindications to TDR in a series of patients undergoing fusion was investigated.
These contraindications were derived from the Charité and ProDisc IDE studies. The results substantiate that all patients in one study had at least one contraindication to TDR10 and less than 5% had no contraindications in the other study.11 The most frequent contraindication was a degenerative facet joint. We may conclude from these studies that the typical CLBP patient is rarely a “good” candidate for TDR.

To summarize, this patient presenting with chronic low back pain identifiable to a single–level structural cause at L5-S1, confirmed by provocative discography, without any evidence of extra spinal issues of pain perception or secondary gain, would be best managed with a fusion. The specific procedure offered is left to the surgeon’s discretion. Although TDR has theoretical advantages, there is no compelling evidence that a disc replacement procedure would provide better outcomes than a fusion or prevent problems in the future. Without this data, prudence requires to offer this patient a time–tested and well established procedure to improve his quality of life and pain.

References
1. Chou R, Baisden J, Carragee E, Resnick D, Shaffer W, Loeser J. Surgery for low back pain: a review of the evidence for an American Pain Society Clinical Practice Guideline. Spine. 2009;34:1094-1109.

2. Fritzell P, Haag O, Wessberg P, et al. Swedish Lumbar Spine Study Group. 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine. 2001;26:2521-2543.

3. Blumenthal S, McAffee P, Guyer R, et al. A prospective, randomized, multicenter Food and Drug Administration Investigational Device Exemption study of lumbar total disc replacement with the Charité artificial disc versus lumbar fusion: part I: evaluation of clinical outcomes. Spine. 2005;30:1565-1575.

4. Guyer R, McAfee P, Banco R, et al. Prospective, randomized, multicenter Food and Drug Administration Investigational Device Exemption study of lumbar total disc replacement with the Charité artificial disc versus lumbar fusion: five-year follow-up. Spine J. 2009;9:374-86.

5. Lemaire J, Carrier H, Ali-el H, et al. Clinical and radiological outcomes with the Charité trade mark artificial disc: a 10 year minimum follow-up. J Spinal Dis Tech. 2005;18:353-359.

6. David T. Long term results of one level lumbar arthroplasty: minimum 10-year follow-up of the Charité artificial disc in 106 patients. Spine. 2007;32:661-666.

7. McAfee P, Cunningham B, Holsapple G, Adams K, et al. A prospective, randomized, multicenter Food and Drug Administration Investigational Device Exemption study of lumbar total disc replacement with the Charité artificial disc versus lumbar fusion: part II: evaluation of radiographic outcomes and correlation of surgical technique accuracy with clinical outcomes. Spine. 2005;30:1576-1583.

8. Wai E, Santos E, Morcom R, Fraser R, Magnetic resonance imaging 20 years after anterior lumbar interbody fusion. Spine. 2006;31:1952-1956.

9. Van Ooij A, Oner F, Verbout A. Complications of artificial disc replacement – a report of 27 patients with the SB Charité disc. J Spinal Disord. 2003;16:369-383.

10. Wong D, Annesser B, Birney T, et al. Incidence of contraindication to total disc arthroplasty: a retrospective review of 100 consecutive fusion patients with a specific analysis of facet arthrosis. Spine J. 2007;7:5-11.

11. Huang R, Lim M, Girardi F, Camissa F. The prevalence of contraindications to total disc arthroplasty in a cohort of lumbar surgical patients. Spine. 2004;29:2538-2541.

Author Disclosures

• R Guyer: Royalties: Depuy, Level B; K2M, Level C. Stock: Spinal Motion. <1%. Private Investments: Spinal Ventures I and II, <5%. Consulting: Depuy, Level B; Alphatec, Level A. Speaking/Teaching Arrangements: Synthes, Level C. Scientific Advisory Board: K2M, Level B; Flexuspine, stock options. Fellowship Support: Depuy, Level E (paid to TBI Research Foundation).
  
  
• L Jenis: Consulting: Stryker, Stryker Biotech, Apatech, BioSet, Arteriocyte, Level B each. Scientific Advisory Board, Apatch, Level B. Research Support–Staff and/or Materials, Styker Biotech, Level D.
  
  
• J Wang: Royalties: Medtronic, Level D (2008); Stryker, Level E; Seaspine, Level E; Osprey, Level B; Aesculap, Level B; Biomet, Level B; Depuy, Level B; Amedica, Level B; Zimmer, Level C; Alphatec. Level not currently available. Stock: Fziomed, <15%. Private Investments: Promethean Spine, Paradigm Spine, Benevenue, NexGen, K2 Medical, Pioneer, Amedica, Vertiflex, Electrocore, Surgitech, Invuity, Axiomed, <1% each. Consulting: Fziomed, previously Level B; Medtronic, Level A; Lanx, Level F (2008 licensing agreement has expired); MTF, Level B; Facet Solutions, Level B; Depuy, Level B. Speaking/Teaching Arrangements: Stryker, Level C; Seaspine, Level B; Vertiflex, Level D. Trips/Travel: Depuy, Level B (reimbursement); Stryker, Level B (reimbursement). Board of Directors: NASS, CSRS. Scientific Advisory Board: VG Innovations, Corespine, Expanding Orthopaedics, Syndicom, Osprey, Flexuspine, Amedica, Bone Biologics, Curative Biosciences, <1%; Facet Solutions, PearlDiver, Pioneer, Seaspine, <1% each; Axis, nonfinancial. Grants: Fonar, Level B. Fellowship Support: AO Foundation, Level E (expired).
  
  

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