**3. Results**

In the group of patients with neurological signs or symptoms 66 patients (88%) had per definition (Teigland et al., 1990) a pathological AS of more than 2 mm, with an average of 10.7 (SD, 3.8) mm, and 40 patients (53%) had an AS of more than 10 mm, with an average of 13.2 (SD, 2.0) mm. In 24 patients (32%) the VS was 25 mm or less (normal values 30 mm or more), with 9 patients (12%) having an impaction between 5 and 9 mm, and 15 patients (20%) an impaction of 10 mm or more. In 23 patients (31%) SS was found in the cervical column, in 10 patients at 1 level, 6 patients at 2 levels, 2 patients at 3 levels, and in 5 patients at 4 levels. The levels were C2/C3 in 10 cases, C3/C4 in 15 cases, C4/C5 in 13 cases and C5/C6 in 10 cases. There was a significantly (*p*<0.001) higher incidence of SS in the group of patients


AS - Anterior subluxation

VS - Vertical settling

SS - Subaxial subluxation(s)

Table 4. Operated RA Patients with Cervical Subluxation with (N=75) and without (N=142) Neurological Symptoms or signs. Severity of Dislocations Distributed between the two Groups with Statistical Differences. Absolute Numbers (percentages)

Alive 24 9.6 (4.6) 20.6 (7.6) 7 (29) Dead 51 9.3 (5.2) 16.9 (8.6) 16 (31)

Alive 49 11.5 (2.4) 21.7 (4.3) 0 Dead 93 11.1 (3.1) 20.7 (5.9) 2 (2)

Neurological Symptoms or signs. Distribution among Alive and Dead during the Follow-up

In the group of patients with neurological signs or symptoms 66 patients (88%) had per definition (Teigland et al., 1990) a pathological AS of more than 2 mm, with an average of 10.7 (SD, 3.8) mm, and 40 patients (53%) had an AS of more than 10 mm, with an average of 13.2 (SD, 2.0) mm. In 24 patients (32%) the VS was 25 mm or less (normal values 30 mm or more), with 9 patients (12%) having an impaction between 5 and 9 mm, and 15 patients (20%) an impaction of 10 mm or more. In 23 patients (31%) SS was found in the cervical column, in 10 patients at 1 level, 6 patients at 2 levels, 2 patients at 3 levels, and in 5 patients at 4 levels. The levels were C2/C3 in 10 cases, C3/C4 in 15 cases, C4/C5 in 13 cases and C5/C6 in 10 cases. There was a significantly (*p*<0.001) higher incidence of SS in the group of patients

> **Operated with Neurology N (%)**

Moderate AS 3 – 10 mm 26 (35) 32 (22) 0.055 Severe AS > 10 mm 40 (53) 107 (73) 0.001 Moderate VS 21 – 25 mm 9 (12) 13 (9) 0.13 Severe VS ≤20 mm 15 (20) 14 (10) 0.04 SS at one level 10 (13) 2 (1) < 0.001 SS at two or more levels 13 (17) 0 (0) < 0.001

Table 4. Operated RA Patients with Cervical Subluxation with (N=75) and without (N=142) Neurological Symptoms or signs. Severity of Dislocations Distributed between the two

Groups with Statistical Differences. Absolute Numbers (percentages)

Table 3. Cervical Spine Subluxations in Operated RA Patients with and without

Period. Total Numbers, Mean values with Standard Deviations (SD)

All 217 10.7 (3.6) 19.7 (7.0) 25 (12) Alive 73 10.9 (3.4) 21.2 (5.9) 7 (10) Dead 144 10.5 (4.0) 18.8 (7.5) 18 (13)

Operated with neurology

Operated without

AS - Anterior subluxation VS - Vertical settling SS - Subaxial subluxation(s)

AS - Anterior subluxation VS - Vertical settling SS - Subaxial subluxation(s)

neurology

**3. Results** 

**Total N AS (mm) VS (mm) SS N (%)** 

75 9.4 (4.5) 18.2 (8.3) 23 (31)

142 11.2 (2.9) 21.1 (5.3) 2 (1)

**Operated without** 

**Neurology N (%)** *<sup>P</sup>*

with cervical neurological symptoms or signs. In the group of patients operated without relevant neurology there were only 2 patients with SS. The incidence of severe VS was higher in the group of patients with relevant neurology (*p*=0.04). Interestingly, severe AS was significantly higher in the group of patients without relevant neurology (*p*=0.001) (Table 4). The survival rate of the studied cohort with neurological symptoms or signs was significantly reduced (*p*<0.001) when compared to the cohort of RA patients without relevant neurology operated for involvement of the cervical column (Figure 1).

Fig. 1. Survival for operated RA patients with and without preoperative cervical neurological symptoms and signs.

Increased Mortality Rate in Rheumatoid Arthritis Patients with Neurological Symptoms

without undue risk for the patient (Kim & Hilibrand, 2005; Santavirta et al., 1988).

neural compression and vascular impairment (Delamarter & Bohlman, 1994).

Praveen & Regis, 2005) after this study.

neurological complications.

neurological findings.

**5. Conclusion** 

indicating that delayed treatment may be hazardous.

reduce the danger of developing neurological complications.

or Signs Secondary to Cervical Spine Subluxations – Reduced Mortality if Postoperative... 271

al., 1998; Matsunaga et al., 2003) as well as preventing progression of existing neural lesions

When cervical neurological symptoms or signs have developed, the literature agrees that there is indication for operative treatment (Kim & Hilibrand, 2005). In addition to reducing pain, neurological recovery is more consistent with lower grade of preoperative myelopathy (Monsey, 1997). An autopsy study suggests that paralysis may be due to both mechanical

It is claimed that patients with no clear radiographic evidence of fusion following occipitocervical instrumentation seemed to do just as well as those who have obvious fusion (Moskovich et al., 2000). In our total series of patients (Paus et al., 2008) we came to the same conclusion. However, when we consider the most severely affected patients (i.e. those with neurological symptoms or signs as in the present study), we find a significant better prognosis if ankylosis is achieved. To obtain a higher proportion of bony ankylosis we have changed operative method from Brattstrøm and Granholm (1976) to transarticular screws (Claybrooks et al., 2007; Cornefjord et al., 2003; Haid, Jr. et al., 2001; Henriques et al., 2000;

In our minds, based on the present findings, patients with relevant neurology are late for operation, their prognosis being worse, and we advise that operative treatment is initiated prior to the development of neurological symptoms or signs. We disagree with the routine of conservative treatment until neurological complications develop. Residual neurological deficit following operation also resulted in a reduced prognosis in the present study,

The high incidence of neurological involvement in patients with SS is well described in the literature (Moskovich et al., 2000; Stirrat & Fyfe, 1993), and we find that this group of patients has a worse prognosis. Our conclusions regarding these patients are more cautious as the operative procedure is more elaborate and carries a higher risk of morbidity, but despite this these patients may benefit from operation prior to the development of

VS can be stopped by AA fixation (Grob, 2000) and patients with neurological symptoms or signs have a significantly more serious settling. In patients with VS, early fixation may

AS is the most frequently occurring dislocation in the spinal neck with an increasing number with increasing severity in both operated groups. However, severe AS is significantly more frequent in the non-neurological group, while SS and VS are overrepresented in the group with relevant neurology. This suggests a weak association between degree of AS per se and neurological phenomena. In the non-neurological group, the majority of patients are operated related to severe AS. As neurological symptoms or signs with indication for surgery may develop before severe AS occurs in patients with SS and VS, this may explain the reduced number with severe AS in the group with relevant

Development of neurological symptoms or signs in RA patients with cervical subluxations significantly increases the mortality rate. It is therefore important to diagnose these patients

The presence of a significant interaction term (*p*=0.015) indicates that the hazard for death changes over time postoperatively for the group with cervical neurological findings. The hazard ratio for this group compared with the group without relevant neurology starts at 2.69 for the first time period following operation decreasing to 2.47 at about 6 years postoperatively, indicating that the postoperative hazard ratio is different for the group with relevant neurology than for the group without. The older the patient is at operation, the hazard for death increases with 6% for each year of age (*p*<0.001), and the patients with relevant neurology have a 169% increased hazard each year (*p*=0.001). We also calculated that males have a 40% higher annual risk, but this difference was not statistically significant (*p*=0.07) (Table 5).


HR indicates Cox proportional hazard ratio; CI=95% Confidence interval

Table 5. Cox Proportional Hazard Ratio Regression for Survival in Operated Patients with and without Neurological Symptoms or signs.

Postoperatively 7 (9%) of the patients experienced residual neurological symptoms or signs. None of these were alive at the end of the study, indicating a poor prognosis for patients with residual cervical neurology after surgery (*p*=0.015).

In 4 patients (5%) reoperation was performed: rearthrodesis in 3 patients, fistula with removal of cement in 1. Additional operation with local superficial release of the greater occipital nerve was necessary in 2 patients (Table 2)

Among those still alive at the end of the follow-up 18 patients had had an arthrodesis performed, and all of these developed bony ankylosis. In the group of patients that died during the follow-up period 49 had had an arthrodesis performed, but only 33 achieved bony ankylosis which is a significantly poorer result (*p*=0.004).

Only 3 of the patients without neurological symptoms or signs before the operation developed relevant neurology during the follow-up period.
