Symptomatic atlantoaxial pannus formation in rheumatoid arthritis

Summary

Limited data from one small cohort study and five very small case-series studies suggest that outcomes are good following either odontoid resection or C1 / 2 fusion alone for treatment of symptomatic atlantoaxial pannus in rheumatoid arthritis. Functional status and pain were improved with both treatments. However, no conclusions can be drawn on the efficacy of one treatment over another, as there were no direct comparisons of the treatments and very limited quantitative data from the case series. Comparative studies with similar patient populations and concurrent controls are needed in order to determine the effectiveness of one treatment over another.

Appendix references:

• 1 Chapman J R, Hanson B P, Dettori J R. et al .Spine Outcomes Measures and Instruments; 1st ed. Stuttgart, New York: Thieme 2007: 72, 146
• 2 Fries J F, Spitz P W, Young D Y. The dimensions of health outcomes: the health assessment questionnaire, disability and pain scales.  J Rheumatol. 1982;  9 789-793
• 3 Conaty J P, Mongan E S. Cervical fusion in rheumatoid arthritis.  J Bone Joint Surg [Am]. 1981;  63 1218-1227
• 4 Steinbrocker O, Traeger C H, Batterman R C. Therapeutic criteria in rheumatoid arthritis.  JAMA. 1949;  140 659-662

Clinical notes

Marco Medina, Perú

Many patients with rheumatoid arthritis (RA) develop atlantoaxial subluxation and if they also present with severe pannus they show, amongst other neurological symptoms, occipitocervical pain, sensation of instability in the head, paresthesias, and a feeling of weakness and awkwardness in the hands; they may also present with obvious signs of cervical myelopathy, hydrosyringomyelia, and hydrocephalus, with basilar invagination and vertebrobasilar syndrome.

In our experience, in view of all the complications arising from an anterior compression and the expectations for postsurgical recovery, we tend to favor a surgical procedure with resection of the odontoids and pannus, with subsequent posterior fusion, on the assumption that a timely intervention would allow a better prognosis for the patient and therefore better expectations for his quality of life.

However, the technical difficulties and the risk associated with anterior intervention have to be weighed up and one has to be more selective with regard to the choice of patient, considering, among other criteria, the irreducibility of the atlantoaxial subluxation and the persisting compression caused by the pannus. It is also important to assess which of the two surgical options affords us the certainty of decompression and not only the possibility of stabilization.

If the choice were to be fusion by posterior approach, the possibility of a second surgical intervention for anterior decompression should not be excluded until the clinical evolution and the radiography suggest that this is in fact not necessary.

Another criterion for the decision as to which of the two interventions is most appropriate is to assess the rate of progression of the symptoms, because although in rare cases a severe and sudden neurological deficit may occur. If this is the case it would be the most clear indication for intervention for decompression by anterior approach, followed up by posterior fusion.

The publications reviewed do not provide a significant level of evidence that would allow consistent recommendations to be made; the majority are reviews of cases (CoE IV), only one of them concerns a cohort of cases (CoE III), and in general the review of other publications shows similar levels of evidence.

Studies with a better level of evidence (CoE I), which would allow clarification of the advantages of one method over the other, are required.

To summarize, we could say that the choice of the route of intervention would depend on analysis of the following factors: 1) presence of neurological deficit due to medullary compression, 2) severity and rate of development of the clinical picture, 3) presence of pannus with evident compression, documented by radiography, 4) irreducibility of the subluxation, and 5) the availability of resources and the surgeon's skill in performing one surgical intervention or the other.

Clinical notes

Luiz Roberto Vialle, Brazil

This revision brings some important remarks to light. The impossibility to state that there is absolute superiority from one method over the other is emphasized. Among the difficulties for analyzing the related publications are the variety of clinical presentations, lack of standardization, and selection of patients. In the face of the data obtained it is clear that there is no essential difference between both techniques. Based on the searched evidence, we may not state that odontoid pannus resection or C1 / 2 posterior fusion are the primary indication for rheumatoid arthritis (RA) instability or myelopathy.

The transoral approach was always associated with a high morbidity. Since new surgical instruments and techniques besides proper training were applied the complication rate from this procedure was lowered, but it is still not easily manageable.

On the other hand, there are also complications related to posterior surgery, pseudarthrosis not being the only one. Here, also modern implants allow us to perform a highly successful fusion in RA bones.

But from literature and from my own experience, I may say that once we get a solid fusion or even segmental immobilization, the pannus will be reabsorbed, so the anterior surgery has no reason if pannus removal is the objective. Unless a patient has a fixed deformity with myelophaty due to compression, most cases of C1–2 instability, with or without cranial settlement or anterior pannus, may benefit from a single posterior surgery.

Although followers of both approaches, isolated or combined, may have good results with their preferred indication, we must remember, according to this review, that their results are similar. However, a given case might have a clear indication for anterior, posterior, or combined surgery, so what should we do? A suggestion from the reviewed articles would be a classification in groups according to the flexible or fixed deformity, cranial settlement, instability degree, as well as neurological involvement. We must address the case needs, selecting the best procedure for that. Proper judgment and performance will determine a good outcome.

In summary, its be the surgeon's personal experience that will count for the decision making, but I hope that this volume may be of help. Again, as well as with other modern literature reviews, future multicenter well-designed prospective studies must be developed in order to answer our questions.