Incidence of contraindications to total disc arthroplasty: a retrospective review of 100 consecutive fusion patients with a specific analysis of facet arthrosis

Abstract

Background context

The role of total disc arthroplasty (TDA) in the treatment of spinal pathology is unclear. TDA has been touted as an alternative to fusion. However, not all back pain is purely discogenic in origin. Contraindications to TDA exist. At Spine Week in Porto, Portugal, Cammisa's group from the Hospital for Special Surgery in New York presented a series of 56 fusions where 100% of patients had one or more of 10 contraindications to TDA. En face, this appears to be an extremely large number.

Purpose

The purpose of the study was to repeat the Hospital for Special Surgery study in another cohort of fusion patients.

Study design/setting

This study was an independent, retrospective record review of 100 consecutive lumbar spinal fusions performed at a tertiary care private medical center.

Patient sample

All adult patients having primary1–3 level lumbar spinal fusions from January 2003 to May 2004 were assessed.

Outcome measures

Physiologic measures included imaging, range of motion, and response to facet blocks.

Methods

A retrospective chart review was performed of 100 consecutive patients having primary 1–3 level lumbar fusion by all five active staff spinal surgeons (3 orthopedic and 2 neurosurgeons). The review was performed independently by the doctorate level physiotherapist who serves as the medical center's research coordinator, reporting to the chairman of the Hospital institutional review board. The same 10 contraindications from Cammisa's study were noted. Additional facet arthrosis data were collected, including mention on imaging reports or operating room notes. Clinical notes were reviewed for documentation of range of lumbar motion (ROM) and whether there was restricted or painful extension ROM. Note was made if patients had facet blocks as another clinical indicator of facet arthrosis.

Results

All 100 patients had at least one contraindication to TDA. The average was 3.69 (range 1–7). Only one patient had facet arthrosis as their only contraindication. Facet arthrosis was documented on imaging reports or operating room notes in 97/100. Reduced extension was present in 71/75 charts that documented ROM. Facet blocks were performed in 12/100 and gave greater than 50% relief in nine.

Conclusions

Both our study and Cammisa's indicate that all lumbar fusion patients in our two institutions have at least one contraindication to TDA. The average fusion patient does not appear to have isolated discogenic pain. A large proportion of the patients appeared to have facet arthritis. The point where facet arthrosis definitely constitutes a contradiction to TDA will require analysis during long-term arthroplasty follow-up studies. Suitable patients for TDA may not represent a significant cohort presently undergoing lumbar fusion.

Introduction

The role of total disc arthroplasty (TDA) in the treatment of spinal pathology is unclear [1], [2], [3], [4]. TDA has been touted as an alternative to fusion which would allow resolution of discogenic pain while still maintaining spine motion [1], [2], [3], [4], [5], [6], [7] and reducing the incidence of adjacent segment degeneration [3], [8], [9]. However, it is recognized that not all mechanical back pain is discogenic in origin [9] and that there are a number of decisive and relative contraindications to TDA (Table 1, Table 2) [3], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20]. At Spine Week in Porto, Portugal, June 2004, Huang and Cammisa's group from the Hospital for Special Surgery in New York presented their study evaluating the presence of 10 relatively decisive contraindications to TDA [10] (Table 1) evaluated in a single-surgeon consecutive series of 100 patients undergoing spinal surgery at their institution. The results have subsequently been published [10]. They found that 56/56 (100%) of the patients having a lumbar fusion had one or more of 10 recognized definite contraindications to TDA. Only 5 of the 44 patients having decompressive/nonfusion operations were without TDA contraindications on review of their medical records. En face, this seems to be an extremely high number of patients with contraindications to TDA.

These results highlight the profound difficulty of accurately defining the limits in the lumbar degenerative process that would be optimal for the use of the TDA. Kirkaldy-Willis et al. [21], [22] divided the stages of degeneration of a spinal motion segment into three phases (normal, unstable, stable). Macnab [23] defined X-ray signs of the transition between the normal and unstable phases (the Macnab “Traction Spur”). Farfan and Kirkaldy-Willis [24] suggested that in the degenerative process, the spinal motion segment be viewed as primarily a “three joint complex” (disc and two facet joints). These concepts worked well even in the era before more modern and sophisticated imaging studies and still form the basis for subsequent classifications that have been proposed to take into account pathologic changes seen by more modern techniques of histologic analysis and imaging modalities such as magnetic resonance imaging. Thompson et al. [25] described a five-stage classification based on a pathological analysis of disc degeneration. Thalgott et al. [26] proposed a classification which also began to look at the posterior elements.

The 10 contraindications to TDA used by Huang and Cammisa in their review appear to be the most consistent and decisive through various publications (facet arthrosis, central spinal stenosis, lateral recess spinal stenosis, spondylolysis, spondylolisthesis, herniated disc with radiculopathy, scoliosis, osteoporosis, pseudoarthrosis, deficient posterior elements) (Table 1). Although these 10 represent the most definite contraindication to TDA, more than 50 other contraindications have also been cited (Table 2).

In our view, facet arthrosis appeared to be the contraindication with a relatively imprecise diagnosis and wide clinical spectrum that was most likely to represent a patient selection dilemma for the spine surgeon.

The Hospital for Special Surgery study [10] brought attention to the issue that TDA may not represent a “better” or even an “alternative” surgical procedure to the majority of patients presently undergoing spinal fusion. Their paper broke new ground on this issue. However, as their study was a single-surgeon (F. Cammisa) series, performed in an orthopedic department at an academic medical center, their paper generates another tier of questions to be answered:

• Do the results reflect the referral pattern of one particular orthopedic spine surgeon, or do they apply over multiple surgeon practices?

• Are the findings consistent across different subspecialties (orthopedic surgery, neurosurgery)?

• Are the findings consistent across different practice settings (academic vs. private medical center)?

• Was the incidence of the 10 contraindications specified weighted more towards the “hard” contraindications (such as herniated disc or spinal stenosis with radiculopathy) or more frequently a relatively “soft” contraindication (such as facet arthrosis)?

• If facet arthrosis is viewed as a relative rather than absolute contraindication to TDA, what is the clinical spectrum of this pathology in patients having surgical fusion?

• Can patients with facet arthrosis be subdivided into clinically relevant subgroups in a manner that would assist with surgical treatment decision?

This study was undertaken to compare the contraindications found in a cohort of patients undergoing fusion at our private medical center with the group at the Hospital for Special Surgery. Patients from both the Orthopedic and Neurosurgery Departments, from several different practice groups were reviewed. A further in-depth chart review was performed to analyze the diagnosis of facet arthrosis and determine the incidence of clinically significant facet disease which likely represented a definite contraindication to TDA.