Outcome analysis of surgeries around craniovertebral junction

Abdul Naim Ostagar; Rajan Kumar; Nasim Akhtar; Sisir Das; Arkadeb Kar

doi:10.4103/ijors.ijors_17_21

ORIGINAL ARTICLE

Year : 2021 | Volume : 29 | Issue : 1 | Page : 3-8

Outcome analysis of surgeries around craniovertebral junction

Abdul Naim Ostagar¹, Rajan Kumar¹, Nasim Akhtar¹, Sisir Das¹, Arkadeb Kar²
¹ Department of Spine and Neurosurgery, AMRI Institute of Neurosciences, AMRI Mukundapur, Kolkata, West Bengal, India
² Department of Community Medicine, Malda Medical College, Malda, West Bengal, India

Date of Submission	07-Jul-2021
Date of Acceptance	08-Jul-2021
Date of Web Publication	21-Aug-2021

Correspondence Address:
Abdul Naim Ostagar
Department of Spine and Neurosurgery, AMRI Institute of Neurosciences, AMRI Mukundapur, Kolkata, West Bengal.
India

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/ijors.ijors_17_21

Abstract

Background: The craniovertebral junction (CVJ) is mainly affected by various bony developmental anomalies. Other causes of compression include trauma, tumors, atlantoaxial instability, and infection (tubercular/pyogenic). We have surgically treated 38 patients of CVJ utilizing different procedures over a span of 4 years and done retrospective study. The purpose of this paper is to analyze the outcome of surgeries around CVJ. Materials and Methods: In our institution, from September 2015 to August 2019, 38 patients underwent surgeries by different methods around CVJ and a retrospective analysis was done. Clinico-radiological evaluation was done to assess the results. The neurologic recovery rate was calculated by Japanese Orthopaedic Association (JOA) score. Results: There were 31 male and 7 female patients in our study with a mean age of 49.8 years (2–86 years). Three (3) anterior surgeries, one (1) combined anterior-posterior 360º fusion, and 34 posterior surgeries including 22 atlantoaxial fixations were done. Average JOA pre-op was 11.6 (range 4–16), at last follow-up average JOA is 14.1 (range 6–16). Radiologically, fusion was achieved in all except two cases. Conclusion: We conclude that CVJ procedures are safe and effective, posterior-only surgery gives promising results with high fusion rate and neurological improvement in most of the patients.

Keywords: Craniovertebral fusion, craniovertebral instability, craniovertebral junction

How to cite this article:
Ostagar AN, Kumar R, Akhtar N, Das S, Kar A. Outcome analysis of surgeries around craniovertebral junction. Int J Orthop Surg 2021;29:3-8

How to cite this URL:
Ostagar AN, Kumar R, Akhtar N, Das S, Kar A. Outcome analysis of surgeries around craniovertebral junction. Int J Orthop Surg [serial online] 2021 [cited 2023 Mar 26];29:3-8. Available from: https://www.ijos.in/text.asp?2021/29/1/3/324271

Introduction

The craniovertebral junction (CVJ) comprises the occiput, atlas, and axis as bony components.^[1] Many ligaments and surrounding muscles help this complex bone anatomy mobile yet stable. Brainstem, cervical spinal cord, and vertebral arteries are vital parts in this area.^[2] Our concern in neural compression in this CVJ region may come from bony developmental anomalies such as occipital condylar hypoplasia, condylus tertius, basiocciput hypoplasia and C1 assimilation, C1 hypoplasia, C1 aplasia, split atlas (posterior and anterior arch rachischisis), persistent os terminal, odontoid aplasia, and os odontoideum. Other causes of compression include trauma, tumors, atlantoaxial instability, and infection (tubercular/pyogenic).^[3]

Treatment option depends on the nature of compression (direction, mechanics), etiology, and associated bony abnormality. Reducibility of bony compressive abnormalities at and around CVJ is an important factor influencing the approach of surgery.^[3] Reducibility was assessed pre-operatively by dynamic imaging, imaging with pre-operative traction, or pre-operative traction and positioning under general anesthesia. Stabilizing a reducible abnormality may produce a “functional decompression.”

Anterior surgery at CVJ has three routes: transnasal, transoral, and transcervical. Transnasal with endoscopy assistance has reduced morbidity with extended surgery like maxillectomy.^[4] Transoral surgery also has reduced morbidity and mortality with the introduction of pre-operative neuroimaging, navigation, and neurophysiological monitoring systems. The cervical approach has limitation reaching higher odontoid and clinical pathology. Posterior approach to CVJ has more rigid instrumentation options and less morbidity and mortality made it more reliable.^[5] Many authors follow “always posterior strategy” even in an irreducible atlantoaxial dislocation (AAD). We have surgically treated 38 patients of CVJ utilizing different procedures over a span of 4 years and done retrospective study. The purpose of this paper is to analyze the outcome of surgeries around CVJ.

Materials and Methods

From September 2015 to August 2019, 38 patients underwent surgeries around CVJ in the neurosurgery department of our institute. Their medical records including demography, pre-operative, intra-operative, and post-operative neurology, imaging, and follow-up were reviewed retrospectively. They had been followed up for a mean of 25 months and 15 days (1–51 months). Thirty-one males and seven females, with a mean age of 49.89 years (range 2–86 years) were included. Any procedures at and around CVJ involving any of occiput, atlas, or axis bone were included. The pathology included trauma (5 hangman fractures, 3 odontoid fractures, 1 sub-axial trauma), AAD (12 idiopathic, 2 traumatic, 2 degenerative), 1 basilar invagination, 1 rheumatoid arthritis, tumors (2 intraspinal neurofibromas, 1 metastasis CA thyroid), congenital (2 CVJ anomalies, 2 Arnold Chiari malformation, 1 meningomyelocele), 2 spondylotic myelopathies which needed laminectomy of C2 and 1 extradural abscess. Each patient underwent pre-operative imaging of X-ray and MRI. Dynamic flexion–extension films were not done in patients with acute trauma to avoid neurological deterioration. CT angiogram was done in all CVJ anomalies and a few selective cases in which the position of vertebral arteries needed to be evaluated.

Surgical planning was done after evaluating different factors including site of compression, the reducibility of fracture or dislocation, duration after trauma, patients’ general condition, neurology, age, and obesity. Type II hangman fractures were treated anteriorly, and type III was dealt with posterior fixation or combined anterior and posterior (360º) approach. Displaced odontoid fracture was more than 6 weeks old. All reducible AADs were fixed posteriorly, and C1-C2 joint spacers were used in case of basilar invaginations. Odontoid screw fixation was done in type II dens fracture, which is less than a 6-week-old trauma.

Surgical techniques

Anterior surgeries were done in the supine position, sandbag under the shoulder with neck extension with or without Gardner-Wells skeletal traction [Figure 1]. Odontoid fixation was done using a single cannulated lag screw under c arm guidance.^[6]

Figure 1: Position of the patient in anterior surgery showing supine positioning (A) and landmarking before incision (B)

Click here to view

In posterior fixation surgeries, patients were positioned prone on a carbon frame table and horseshoe headrest. O arm with Stealth S8 navigation was used in selected cases; otherwise, C arm guidance was used for implant placement. Posterior midline incision and subperiosteal dissection were carried out at the desired level. C1, C2, and occiput are exposed in the midline, and subperiosteal blunt dissection was carried out laterally. Bleeding from C2 ganglion or abnormal bleeding was managed with bipolar or wet cotton compression. The reference frame is placed in the sub-axial spinous process, and navigation-guided drilling, tapping, and screw placement were done when O arm is used. C1-C2 joint spacers are usually placed retracting C2 nerve roots, sometimes sacrificing it.^[7] Goel’s plate and Goel–Harms technique using C1 lateral mass and C2 pedicle screw with rod fixation are used mostly for C1-C2 fixation.^[8] Transarticular screw has not been used in our study. Wound is closed in layers with or without a subfascial drain.

Choice of implant and the extent of decompression if needed were decided by the operating surgeon studying the cases individually. Bone grafts used for fusion are either autologous (from local bone, i.e., lamina, spinous processes, ribs, or iliac crest) or synthetic graft (Mastergraft^®).

Using O arm or C arm intra-operatively, operating time and drain insertion were noted. Pre-operative and post-operative complications are noted. Pain (VAS score) and neurology using Japanese Orthopaedic Association (JOA) score^[9] were assessed preoperatively, at 1 month, 6 months, and yearly follow-up thereafter. Fusion is assessed in dynamic X-ray during follow-up, with the absence of any instability or implant loosening along with the presence of homogeneous fusion mass. CT scan was advised in selected cases.

Results

Clinical results

There were 31 male and 7 female patients in our study with a mean age of 49.8 years (2–86 years). Three (3) anterior surgeries, one (1) combined anterior-posterior 360º fusion, and 34 posterior surgeries including 22 atlantoaxial fixations were done. Unilateral, bilateral, and occipitocervical fixations were done, depending on the pathology [Figure 2]. Two (2) cases with basilar invagination were managed using C1-C2 spacers along with C1-C2 fixation. C1-C2 fixation in four cases was fixed unilaterally, and one C1-C2 fixed with ATLAS^® cable. All three anterior surgeries were transcervical; no transoral or transnasal procedure was performed.

Figure 2: Post-operative radiographs of patients showing unilateral fixation of C2/C3 (A), bilateral fixation of C2/C3 (B), and occipitocervical fixation (C)

Click here to view

Myelopathy (28 patients) was presenting symptoms in most of the patients, 7 patients had pain without neurodeficit, one meningomyelocele presented with swelling, 1 ACM type II presented with recurrent syncope and a neurofibromatosis presented with myoclonic jerks in lower limbs, and 4 patients presented with occipital neuralgia without myelopathy.

All 10 neurologically intact patients remained the same after surgery. Twenty-three (82.14%) out of 28 myelopathy patients showed improvement. Two patients died within 1 month of surgery, 5 patients showed a poor improvement, 14 patients fair, 7 showed good improvement, at last, follow-up. Average JOA pre-op was 11.6 (range 4–16), and follow-up average JOA is 14.1 (range 6–16). The neurologic recovery rate was calculated as follows: (post-operative JOA score−pre-operative JOA score)/(full score−pre-operative JOA score) × 100. The neurological recovery rate was ranked as excellent (75–100%), good (51–74%), fair (25–50%), poor (0–24%), or worse (<0%).

Eleven patients with trauma had significant pain relief from VAS 4.45 (range 3–6) to average VAS 0.81 (range 0–5). Two patients with pain worsening at 1-year follow-up had initial pain relief. Both found to have fusion failure: one with unilateral C1-C2 screw and another with ATLAS^® cable fixation.

Among anterior surgeries, two type II Hangman fractures treated with C2/3 discectomy with instrumented fusion [Figure 3] and one odontoid fracture underwent screw fixation [Figure 4]. All three achieved successful bony fusion.

Figure 3: Type II hangman fracture; anterior cervical discectomy and fusion done: MRI (A), CT scan (B), and C2/3 post-operative radiograph (C)

Click here to view

Figure 4: Type II odontoid fracture in MRI (A), post-operative radiograph (B) after anterior surgery (odontoid cannulated screw fixation)

Click here to view

Thirty-four posterior surgeries include 22 atlantoaxial fixations. Ten of them were done under O arm Stealth S8 navigation guidance and 12 under C arm guidance.

Six patients had unilateral C1-C2 fixation, three each in O arm and C arm guidance. C1-C2 joint spacer was used in two cases; three patients had occipitocervical fixation and additional occipital plates. One case of metastatic CA thyroid at C1 and C2 regions also underwent occipitocervical fixation [Figure 5]. Unilateral fixations were done instead of bilateral in six cases due to thin fracture of C2 pedicle, fracture C1 lateral mass, or excessive bleeding from C2 ganglion or other surrounding venous plexuses. A case of AAD in an 8-year-old girl was managed with ATLAS^® cable [Figure 6].

Figure 5: Metastatic CA thyroid at C1 and C2 regions evident in MRI (A, B) and posterior occipitocervical fixation (C) done

Click here to view

Figure 6: A case of AAD in an 8-year-old-girl. Pre-operative radiographs (A, B) and MRI (C), managed with ATLAS^® cable (D)

Click here to view

Radiological results

Two cases of fusion failure at 1-year follow-up were seen. ATLAS^® cable fixation failure was seen with recurrence of subluxation and cable in situ. Unilateral fixation of C1-C2 failure demonstrated dynamic instability of C1-C2 after pain increased at the operating site.

Rest of the cases with instrumentation showed features of fusion till last follow-up.

Complications

Intra-operative complication includes failure of bilateral fixation due to lateral mass fracture C1 (two cases) and pedicle fracture C2 (two case). One case of C3 lateral mass fracture needed extended fixation. Dural tear encountered in one case repaired under a microscope.

In the immediate post-operative care, two patients deteriorated neurologically. One patient with Arnold Chiari malformation with C1-C2 fixation had transient altered sensorium and improved over 2 days. Another patient with CVJ epidural abscess had increased weakness of limbs and needed extended decompression the next day. Two fusion failures were detected at 1-year follow-up: one with ATLAS^® cable and another with unilateral C1-C2 fixation.

Discussion

The compression of CVJ is either static (mainly CVJ anomalies and trauma) or dynamic (due to C1-C2 instability). These compressions lead to high cervical myelopathy, sometimes along with lower cranial nerve palsy and respiratory compromises. Instrumentations are used aiming to achieve rigid fusion as well as indirect decompression in many scenarios. Atlanto-occipital and atlantoaxial joints are major contributors of motion in the head and neck region. CVJ fusions produce significant morbidities after sacrificing the mobility of these joints. Therefore, limited fusions and future research on developing implants for CVJ to achieve stability without sacrificing major motion should be our goal.

The outcome of our series showed that CVJ procedures are safe and effective, posterior-only surgery gives promising results with high fusion rate and neurological improvement in most of the patients. Wire and cable fixation may be considered “old-fashioned” and weaker devices compared with screw-rod devices, but it is simple, safe, and economical. In our study, we noticed that unilateral fixations have a higher chance of fusion failure, and there was more pain in the postoperative period till fusion was achieved. We recommend wire construct along with unilateral screw-rod fixation in which bilateral screw fixation was not possible. Use of O arm navigation needs more operating time when compared with C arm-guided instrumentation, with comparable outcomes.^[10],[11] The number of cases was small, and the follow-up period was short in our study. Comparisons between O arm- and C arm-guided cases are not randomized.

Conclusion

CVJ procedures are safe and effective; posterior-only surgery gives promising results with high fusion rate and neurological improvement in most of the patients. Wire and cable fixation may be considered “old-fashioned” and weaker devices compared with screw-rod devices, but it is simple, safe, and economical.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

All the authors declared that there is no conflict of interest.

Authors’ contribution

Dr. Abdul Naim Ostagar: Study design, analysis of data, preparation of manuscript, and reviewed the manuscript.

Dr. Ranjan Kumar: Helped in study design, data collection, pre-operative investigation, and surgical intervention.

Dr. Nasim Akhtar: Helped in study design, pre-operative investigation, surgical intervention, data collection, and preparation of manuscript.

Dr. Sisir Das: Study design, analysis of data, surgical intervention; supervised the study and reviewed the manuscript for final preparation.

Dr. Arkadeb Kar: Study design and statistical analysis of data; reviewed the manuscript for final preparation.

References

1.	Smoker WR Craniovertebral junction: Normal anatomy, craniometry, and congenital anomalies. Radiographics 1994;14:255-77.
2.	Debernardi A, DʼAliberti G, Talamonti G, Villa F, Piparo M, Collice M The craniovertebral junction area and the role of the ligaments and membranes. Neurosurgery 2015;76(Suppl. 1): S22-32.
3.	Joaquim AF, Tedeschi H, Chandra PS Controversies in the surgical management of congenital craniocervical junction disorders—A critical review. Neurol India 2018;66:1003-15.
4.	Dlouhy BJ, Dahdaleh NS, Menezes AH Evolution of transoral approaches, endoscopic endonasal approaches, and reduction strategies for treatment of craniovertebral junction pathology: A treatment algorithm update. Neurosurg Focus 2015;38:E8.
5.	Harms J, Melcher RP Posterior C1-C2 fusion with polyaxial screw and rod fixation. Spine (Phila Pa 1976) 2001;26:2467-71.
6.	Hsu WK, Anderson PA Odontoid fractures: Update on management. J Am Acad Orthop Surg 2010;18:383-94.
7.	Patkar SV New entry point for C2 screw, in posterior C1-C2 fixation (Goel–Harm’s technique) significantly reducing the possibility of vertebral artery injury. Neurol Res 2016;38:93-7.
8.	Goel A. Craniovertebral junction instability: A review. Asian Spine J2015;9:634-44.
9.	Kato S, Oshima Y, Oka H, Chikuda H, Takeshita Y, Miyoshi K, et al. Comparison of the Japanese Orthopaedic Association (JOA) score and modified JOA (mJOA) score for the assessment of cervical myelopathy: A multicenter observational study. PLoS ONE2015;10:e0123022.
10.	Wang YC, Zhou ZZ, Wang B, Zhang K, Chen H, Chen KW, et al. Occipitocervical fusion via cervical pedicle fixation assisted with O-arm navigation. Orthop Surg 2020;12:1100-7.
11.	Jing L, Sun Z, Zhang P, Wang J, Wang G Accuracy of screw placement and clinical outcomes after O-arm-navigated occipitocervical fusion. World Neurosurg 2018;117:e653-9.