Highlights
- •We compared the accuracy of four radiographic anterior cervical fusion criteria.
- •ExGBB criterion demonstrated the highest reliability and accuracy.
- •ISM criterion has comparable accuracy to the CT scan as initial diagnostic test.
- •Bridging bone and InGBB criteria were less accurate in case used cage We recommend ISM and ExGBB criteria to increase accuracy in case used cage.
Abstract
BACKGROUND CONTEXT
The accuracy of radiographic criteria for determining anterior cervical fusion remains
controversial, and inconsistency in the literature makes a comparison of published
clinical results problematic. The descriptions of bridging bone are still lacking
and subjective, and the interpretation of images can be influenced by the type of
graft or cage used.
PURPOSE
To assess and validate the diagnostic accuracies of four radiographic fusion criteria
using the results of surgical exploration.
STUDY DESIGN
Retrospective, radiographic, and comparative study.
PATIENT SAMPLE
This study included patients who required anterior or posterior exploration of a previous
anterior cervical arthrodesis level(s) ranging from C3–C4 to C7–T1 for suspected pseudarthrosis
or adjacent-segment pathologies. They underwent radiologic examinations to determine
the four fusion criteria. We included patients whose images were taken at least 1
year after the index surgery, and 82 patients with 151 cervical segments were enrolled.
OUTCOME MEASURES
The inter- and intra-rater reliabilities and validity that correlated with the results
of surgical exploration for the four fusion criteria were assessed using data (fusion
or not) that were collected by two raters.
METHODS
The four published radiographic fusion criteria were interspinous motion (ISM) < 1
mm and superjacent ISM ≥ 4 mm, seen on dynamic radiographs; conventional bridging
bone, as seen on computed tomography (CT) scans; and extra-graft bridging bone (ExGBB)
and intragraft bridging bone (InGBB), observed on multi-axial reconstructed CT scans.
The criteria were evaluated by two raters (spine surgeons with 5 and 7 years of experience).
The raters evaluated each criterion twice at two different time points, 3 to 4 weeks
apart. First, ISM and conventional bridging bone on CT scans were evaluated, followed
by ExGBB and InGBB, with a time interval of 4 months. This Research was supported
by the Chung-Ang University Research Grants (less than 5,000 US dollars) in 2016.
RESULTS
The inter- and intra-rater reliability values of the ExGBB (0.887–0.933) criteria
were the highest, followed by those for the ISM (0.860–0.906), bridging bone (0.755–0.907),
and InGBB (0.656–0.695) criteria. The validity values that correlated with the exploration
results were the highest for the ExGBB criteria (k=0.889), followed by the ISM (k=0.776),
bridging bone (k=0.757), and InGBB (k=0.656) criteria and ExGBB showed the highest
sensitivity (91.7%) and specificity (98.4%). Regarding the graft materials that were
used, all criteria had the highest values in the auto-cortical group and lowest values
in the cage group. Of note, sensitivity and specificity of ExGBB were 100% in autocortical
group. In the cage group, the validity values for the ExGBB (k=0.663) and ISM (k=0.666)
criteria were higher than those for the bridging bone (k=0.504) and InGBB (k=0.308)
criteria
CONCLUSION
The presence of ExGBB (anterior, posterior, or lateral to the graft or cage) correlated
the best with surgical exploration. The ISM criteria demonstrated a similar accuracy
to that of conventional bridging bone criteria on CT scans. In arthrodesed segments
with auto-cortical bone, criteria showed the highest validity values. In cage group,
ISM and ExGBB had acceptable accuracy, but the conventional bridging bone and InGBB
were worse than guessing. We recommend that ISM and ExGBB criteria should be used
to increase accuracy in patients who undergo arthrodesis with cages.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to The Spine JournalAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Radiological determination of postoperative cervical fusion: a systematic review.Spine (Phila Pa 1976). 2015; 40: 974-991
- Dynamic radiographic criteria for detecting pseudarthrosis following anterior cervical arthrodesis.J Bone Joint Surg Am. 2014; 96: 557-563
- Methods of evaluating lumbar and cervical fusion.Spine J. 2014; 14: 531-539
- Anterior cervical fusion assessment using reconstructed computed tomographic scans: surgical confirmation of 254 segments.Spine (Phila Pa 1976). 2013; 38: 2171-2177
- When is a spine fused?.Injury. 2011; 42: 306-313
- Prospective analysis of imaging prediction of pseudarthrosis after anterior cervical discectomy and fusion: computed tomography versus flexion-extension motion analysis with intraoperative correlation.Spine (Phila Pa 1976). 2011; 36: 463-468
- Radiographic assessment of cervical subaxial fusion.J Neurosurg Spine. 2009; 11: 221-227
- Radiologic assessment of spinal fusion.J Am Acad Orthop Surg. 2012; 20: 694-703
- Pseudarthrosis of the spine.J Am Acad Orthop Surg. 2009; 17: 494-503
- Diagnosing cervical fusion: a comprehensive literature review.Asian Spine J. 2008; 2: 127-143
- A prospective clinical and radiographic 12-month outcome study of patients undergoing single-level anterior cervical discectomy and fusion for symptomatic cervical degenerative disc disease utilizing a novel viable allogeneic, cancellous, bone matrix (trinity evolution) with a comparison to historical controls.Eur Spine J. 2016; 25: 2233-2238
- Anterior cervical fusion for radicular-disc conflict performed by three different procedures: clinical and radiographic analysis at long-term follow-up.Eur Spine J. 2013; 22: S905-S909
- Clinical and radiological evaluation of Trabecular Metal and the Smith-Robinson technique in anterior cervical fusion for degenerative disease: a prospective, randomized, controlled study with 2-year follow-up.Eur Spine J. 2010; 19: 464-473
- Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up.Eur Spine J. 2008; 17: 698-705
- The measurement of observer agreement for categorical data.Biometrics. 1977; 33: 159-174
- Do CT scans overestimate the fusion rate after anterior cervical discectomy and fusion?.J Spinal Disord Tech. 2015; 28: 41-46
- Anterior cervical fusion assessment: surgical exploration versus radiographic evaluation.Spine (Phila Pa 1976). 2008; 33: 1185-1191
Article info
Publication history
Published online: July 07, 2018
Accepted:
July 2,
2018
Received in revised form:
June 30,
2018
Received:
May 7,
2018
Footnotes
☆FDA device/drug status: not applicable.
Author disclosures: KDR: Honorarium: AOSpine (A). Royalties: BIOMET (F), Medtronic (G). Stock Ownership: Amedica (1%), Benvenue (1%), Expanding Orthopedics (<1%), Nexgen Spine (1%), Vertiflex (1%), Osprey (1%), Paradigm Spine (1%), Spinal Kinetics (1%), Spineology (<1% ), Vertiflex (1%). Consulting: Nuvasive (B), Biomet (unreported), Medtronic (unreported). Speaking/Teaching Arrangements: Epibone (B), Biomet (B), Medtronic ( B), Zeiss (B). Trips/Travel: DEPUY SYNTHES (courses taught for AOSpine, some AOSpine funding comes from Depuy Synthes); Board of Directors: AOSpine (e). Research Support: AO Spine (Paid directly to institution/employer). JJY: Nothing to disclose. DGC: Nothing to disclose. SMP: Nothing to disclose. JSY: Nothing to disclose. JSL: Nothing to disclose. ECJ: Nothing to disclose. KSS: Grants: Chung-Ang University Research Grants in 2016 (B).
Identification
Copyright
© 2018 Elsevier Inc. All rights reserved.
