Background: Atlanto-axial
(C1-C2) osteoarthritis (AAOA) causes severe progressive sub occipital neck pain
that is usually resistant to conservative therapy. Posterior fusion surgery is performed to
stabilise the C1-C2 segment and alleviate the pain. Fusion surgery for neck pain
is considered controversial due to a perceived lack of efficacy.
Methods: 23
Patients who underwent posterior atlanto-axial fixation surgery for AAOA were
enrolled. Patient demographics and surgical technique were recorded. Surgical
technique included trans articular fixation (TAS) and supplemental posterior
Sonntag wiring or C1-C2 lateral mass fixation (Harms technique). Some patients
required a combination of fixation due to anatomical variation. Primary outcome
measures including patient satisfaction, pain, disability scores and range of
motion were recorded for all patients pre- and post-operatively. Post-operative assessment was supplemented
with CT and x-ray imaging.
Results: 23
patients (19 women, 4 males, mean age 71.8 ± 6.3 years) underwent surgical
fixation. 8 underwent TAS, 7 had Harms and 8 had a hybrid fixation. All
patients reported statistically significant improvement in pain scores. Average
VAS preoperatively was 9.4. Average VAS postoperatively was 2.9, P<0.005.
Disability scores (NDI) were statistically significantly reduced from 72 ± 13
pre-operatively to 19 ± 12 post-operatively, P<0.005. Mean follow-up was 55
months. Results did not vary according to the construct type. 95.5% of patients
showed radiographic evidence of fusion.
Conclusion:
Posterior atlanto-axial fusion is highly effective for the surgical treatment
of intractable neck pain secondary to atlanto-axial lateral mass osteoarthritis
(AAOA). Surgery offers a high rate of symptom relief. If anatomical variability
exists, both trans articular and pedicle screw fixation can be used in the same
patient.
Keywords:
Atlanto-axial, Osteoarthritis, C1-C2, Cervical, Fusion, Arthritis
INTRODUCTION
All patients will
develop radiological cervical spondylotic changes with age. Sub axial cervical
spine osteoarthritis (OA) is seen in virtually all patients after age 65.
Atlanto-axial (AA) OA is rare, occurring in only 4% of OA sufferers. It causes
unilateral suboccipital pain exacerbated by lateral rotation on the affected
side with reduced range of movement (Figure 1) [1]. It may be associated
with suboccipital neuralgia. Surgical intervention is considered when
conservative treatment fails. C1-2 fusion was first performed in 1939 using
posterior wiring [2]. Posterior transarticular screw fixation (TAS) was first
performed in 1987 [3]. Harms and Melcher first performed pedicle screw fixation
in 2001. This avoids the need for posterior cable fixation and allows a more
minimally invasive surgical exposure [4].
The surgical
objective is stabilisation of the atlanto-axial joint to provide symptomatic
relief. The purpose of our study is to assess the clinical and radiographic
outcomes of surgical treatment for AAOA by a single surgeon (TS). Radiological
fusion was assessed using x-ray and CT. There has only been one previous study
reporting on hybrid fixation techniques [5].
METHODS
The St Vincent’s
Hospital Human Research Ethics Committee approved this study (SVH file number:
16/054). Patients undergoing posterior atlanto-axial surgery between 2005-2015
at our institution performed by the senior author (TS) were identified.
Demographic data including gender, age, length of hospital-stay and follow-up
time was recorded. Diagnosis was made via clinical and radiological criteria. CT with
bone
window was used
to confirm the
Preoperative and
postoperative satisfaction scores were recorded using the Visual Analogue Scale
(VAS) and Neck Disability Index score (NDI) [6]. Patients were asked if in
hindsight they would have the surgery again. Postoperative range of movement in
flexion, extension and lateral rotation was recorded. Secondary outcome
measures were the presence of fusion and periprosthetic complications assessed
on CT. Joint fusion was assessed by the obliteration of the joint space with
evidence of mature bone fusion across the C1-C2 joint.
Data analysis was
carried out using SPSS Statistics version 23 (SPSS Inc., Chicago Ill USA). Data
is presented as a mean ± standard deviation. One Sample Kolmogorov-Smirnov test
was carried out to assess normality of data set, and Wilcoxson Signed-Rank test
was performed to ascertain significance in measures in the pre-operative and
follow-up setting. Non-parametric tests were used due to the sample size.
Fisher’s exact test was used to determine the independence of the outcome variables.
Statistical significance was accepted at the p<0.05 level.
RESULTS
23 patients with AAOA were enrolled in the
study, 19 female and 4 males (Mean age at surgery was 67.2 (range 51-77). Mean
follow-up time was 55.3 months (range 11-132) (Table 1). All patients had severe progressive pain localised to
the ipsilateral suboccipital region exacerbated by lateral rotation to the
affected side. Most patients had limited range of lateral rotation at time of
presentation. Other preoperative symptoms included suboccipital headache (15
patients), orbital pain (2 patients) and shoulder pain (6 patients). All
patients had been treated conservatively prior to presentation with analgesia,
immobilisation and facet joint injections.
Choice of fixation technique was determined at time of surgery by the
senior surgeon (TS) using image guidance (BrainLab AG Feldkirchen, Germany). 8
patients underwent TAS fixation with posterior wiring and bone graft and 8
patients had lateral mass pedicle screw fixation according to Harms’ method. 7
patients had hybrid fixations with TAS fixation on one side and pedicle screw
fixation on the other due to anatomical variation. TAS fixation was revised in
one patient to a Harms fixation due to lack of fusion 14 months following
initial surgery. One patient with a Harms fixation was revised to a TAS
fixation due to trauma causing fracture of both C1 screws 3 years post initial
surgery.
VAS pain scores were significantly reduced
immediately following surgery. The mean pre-operative VAS was 9.4 ± 0.8
compared to post-operative score of 2.9 ± 2.0 at the time of follow-up
(Z=4.200, p<0.0005). All patients reported virtually complete abolition of
pain postoperatively. In some patients, mild recurrent neck pain recurred 3-4
years following surgery.
Mean NDI score prior to surgery was 72.2 which
reduced to 18.9 post-operatively (Z=4.199, p<0.0005) (Table 1). Pre and post-operative range of movement measures were
identical with lateral rotation most affected. Radiological fusion was shown in
21 patients (95.5%). 2 patients’ scans revealed skull base erosion around the
head of the Harms screw (Figure 2a).
One patient had a non-union with recurrence of pain 4 years post TAS fixation;
CT demonstrated implant loosening and resorption of bone graft (Figure 2b). 21 of the 23 patients
(91.3%) stated they would undergo the surgery again.
DISCUSSION
AAOA has a unique natural history compared to
other degenerative spinal disorders [7,8]. Relatively few studies reporting
outcomes of cervical fusion for AAOA have been published, with only one
meta-analysis of 23 studies containing 246 patients in 2013 [9]. Diagnosis is
often delayed due to non-specific or atypical symptoms and pain management is
often the only treatment offered [9]. C2 radiofrequency lesioning and
ganglionectomy have been trialled to alleviate symptoms [9]. However, these
techniques fail to address the underlying pathology and symptoms inevitably
progress. Internal fixation of the atlantoaxial segment presents a significant
surgical challenge to the spine surgeon, with non-union rate of up to 30%
[10,11]. TAS and pedicle screw fixation achieve a more rigid fixation
fusion-rate >95% [4,12,13].
2 patients in our series had skull base
erosions because of the proximity of the C1 screw heads to the inferior occiput
(Figure 2a). One patient, a 71 year
old female, underwent revision surgery one year following TAS fixation. The
hardware was removed and replaced with lateral mass screws. Right sided neck
pain recurred after one year; imaging showed stable fusion but significant skull
base erosion (Figure 2a). C1 screws
were removed and her pain improved. The second patient, a 66 year old female,
developed right-sided suboccipital pain one year following the surgery. CT scan
revealed similar skull base erosions, more marked on the right side.
Intraoperative stereotactic guidance was used
in all our patients and all screws were in satisfactory position on
post-operative imaging with no screws extending anterior to the C1 vertebra.
Only one study has previously reported the use of the hybrid fixation technique which may be required for anomalies such as a high-riding vertebral artery [5]. The 8 patients in this series who had hybrid fixations achieved identical results to those with TAS or Harms constructs (Figure 3). Our patients report satisfaction with their surgery of greater than 90%, with dramatic improvement in VAS and NDI scores postoperatively. This indicates that posterior atlantoaxial fixation is a highly successful surgical technique for the treatment of symptomatic AAOA.
CONCLUSION
Posterior cervical fixation is a highly
effective technique for the surgical treatment of neck pain secondary to
atlantoaxial lateral mass osteoarthritis (AAOA) that has failed to respond to
conservative measures. The surgery is safe and offers a very high rate of
symptom relief. Trans-articular screw and pedicle screw fusions can be used in
combination with each other to adapt to anatomical and pathological variability
while maintaining an extremely high surgical success rate.
CONTRIBUTIONS
·
Dr Ananya Chakravorty: Paper write-up.
·
Dr Ellen Frydenberg: Data collection, write-up and
submission.
·
Dr Timothy Steel: Original idea, design, write-up.
·
Dr Mitchell Fung: Data collection and paper write-up.
1. Halla
J, Hardin J (1987) Atlantoaxial (C1-C2) facet joint osteoarthritis: A
distinctive clinical syndrome. Arthritis Rheum 30: 6.
2. Gallie
W (1939) Fractures and dislocations of the cervical spine. Am J Surg 46: 5.
3. Magerl
F, Seemann PS (1987) Stable posterior fusion of the atlas and axis by
transarticular screw fixation. Springer, p: 6.
4. Harms
J, Melcher RP (2001) Posterior C1-C2 fusion with polyaxial screw and rod
fixation. Spine 26: 2467-2471.
5. Kang
DG, Lehman Jr RA, Wagner SC, Peters C, Riew KD (2017) Outcomes following
arthrodesis for atlanto-axial osteoarthritis. Spine 42: E294-E303.
6. Vernon
H (2008) The neck disability index: State-of-the-art, 1991-2008. J Manipulative
Physiol Ther 31: 12.
7. Goel
A, Shah A, Gupta SR (2010) Craniovertebral instability due to degenerative
osteoarthritis of the atlantoaxial joints: Analysis of the management of 108
cases. J Neurosurg Spine 12: 592-601.
8. Elliott
R, Tansweer O, Smith M, Frempong-Boadu A (2013) Outcomes of fusion for lateral
atlantoaxial osteoarthritis: Meta-analysis and review of literature. World
Neurosurg 80: 10.
9. Holly
LT, Batzdorf U, Foley KT (2000) Treatment of severe retromastoid pain secondary
to C1-2 arthrosis by using cervical fusion. J Neurosurg 92: 162-168.
10. Gore
D, Sepic S, Gardner G (1986) Roentgenographic findings of hte cervical spine in
asymptomatic people. Spine 11: 4.
11. Bekelis
K, Gottfried O, Wolinsky JP, Gokaslan Z, Omeis I (2010) Severe dysphagia
secondary to posterior C1-C3 instrumentation in a patient with atlantoaxial
traumatic injury: A case report and review of the literature. Dysphagia 25: 5.
12. Neo
M, Matsushita M, Iwashita Y, Yasuda T, Sakamoto T, et al. (2003). Atlantoaxial
transarticular screw fixation for a high-riding vertebral artery. Spine 28: 5.
13. Grob
D, Bremerich FH, Dvorak J, Mannion AF (2006) Transarticular screw fixation for
osteoarthritis of the atlanto axial segment. Eur Spine J 15: 283-291.
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