Clinical studyFusion rate following three- and four-level ACDF using allograft and segmental instrumentation: A radiographic study
Introduction
Symptomatic multi-level degenerative changes with associated myelopathy in the cervical spine is an increasingly common entity [5]. It has been demonstrated in a number of studies that surgical decompression of the cervical spinal cord is an effective treatment option for patients with refractory radiculopathy, severe degenerative disease, or moderate to severe cervical spondylotic myelopathy (CSM) that not only halts the progression of symptoms, but can also promote meaningful functional recovery in a significant portion of treated individuals [6], [17]. Both anterior and posterior approaches are effective in addressing pathology in patients with CSM. In fact, a recent systematic review by the American Association of Neurological Surgeons (AANS) and the Congress of Neurological Surgeons (CNS) concluded that both anterior [Anterior cervical discectomy and fusion (ACDF), Anterior cervical corpectomy and fusion (ACCF)] and posterior approaches (laminoplasty, laminectomy, and laminectomy with fusion) all yielded similar near term functional improvements in patients with CSM [11]. The choice of surgical approach is dependent on multiple factors, including age, general medical status, and comorbidities, cause of compression, primary site of compression, number of levels involved, as well as sagittal alignment of the spine. Anterior approaches are generally preferred when restoration of cervical lordosis is a primary surgical goal. With studies showing suboptimal correction of sagittal imbalance in posterior procedures as compared to anterior approaches, there may be increasing application of anterior approaches for patients with multilevel CSM [14]. Even though multilevel ACDF is a commonly performed surgery, the potential for complications associated with anterior approaches is not negligible, especially dysphagia and pseudarthrosis.
While there is a significant data regarding fusion rates and complications in one- or two-level anterior cervical discectomy and fusions (ACDF), the literature on fusion rates following 3 or more level ACDF particularly using allograft is sparse with variable rates of pseudarthrosis [1], [10], [15], [18], [20]. The pseudarthrosis rates following three- and four-level anterior fusion rates have been reported between 0 and 40% depending on graft type, the use of bone morphogenetic protein (BMP), and the presence of anterior cervical plating [2], [10], [12], [21]. With the increasing number of multilevel ACDFs, it is critical to be aware of overall fusion rates to allow preoperative patient counseling and selection of optimal surgical approach for patients with multilevel cervical spine pathologies. This study reports fusion rates following three- and four-level ACDF using allograft and segmental instrumentation from a single institution.
Section snippets
Methods
A retrospective review was performed to analyze the medical records of all patients who underwent three or more level ACDF procedures with plating from 2009 to 2013 at a major tertiary care academic medical center. The study was approved by the Institutional Review Board. A minimum radiological follow-up of at least 12 months or an earlier need of revision surgery for pseudarthrosis was required for the patient to be enrolled in the study. Standard demographics and clinical variables including
Results
A total of 72 patients met inclusion criteria for the study with demographics as detailed in Table 1. Of the 232 levels operated upon, pseudarthrosis occurred at 47/232 (20.3%) levels. Overall 45.8% of patients (33/72) had a pseudarthrosis, most commonly at the caudal level of the construct. Illustrative examples of pseudarthrosis can be seen in Fig. 1, Fig. 2. Subgroup analysis revealed that the incidence of pseudarthrosis was higher in patients with a 4-level ACDF compared to those with a
Discussion
While ACDF has been shown to be an extremely effective surgery in appropriately selected patients, revision surgery after anterior fusion is sometimes necessary, with rates ranging from 2.1% to 9.3% for single-level procedures and 4.4% to 10.7% for multilevel procedures. The most common causes for revision surgery in this group of patients include adjacent segment disease, pseudarthrosis, progressive deformity, infection, or a combination of these [9]. The incidence of pseudarthrosis is not
Conclusion
The present study demonstrates the incidence of radiographic pseudarthrosis following 3 or more level ACDFs. Though only a minority of patients with pseudoarthrosis may be clinically symptomatic, the possibility of requiring some intervention over long term follow up remains. Alternative surgical strategies for patients at higher risk for pseudoarthrosis may be considered to decrease the incidence of pseudarthrosis following such multilevel ACDFs.
Source of funding
None.
Disclosures
Harel Deutsch reports receiving royalties from Pioneer.
John E. O’Toole reports being a consultant and receiving royalties for Globus Medical and Pioneer Surgical and has stock ownership in Theracell, Inc.
Vincent C. Traynelis is a consultant and receives royalties from Medtronic and receives institutional fellowship support from AO and Globus.
References (21)
- et al.
Anterior cervical discectomy plus intervertebral polyetheretherketone cage fusion over three and four levels without plating is safe and effective long-term
J Clin Neurosci Off J Neurosurg Soc Australas
(2013) - et al.
Comparison of allograft to autograft in multilevel anterior cervical discectomy and fusion with rigid plate fixation
Spine J Off J North Am Spine Soc
(2003) - et al.
Pseudoarthrosis rates in anterior cervical discectomy and fusion: a meta-analysis
Spine J Off J North Am Spine Soc
(2015) - et al.
Multiple-level instrumented anterior cervical fusion: a risk factor for pseudoarthrosis? A prospective study with a minimum of 3-year follow-up
Acta Chir Orthop Traumatol Cech
(2004) - et al.
Peek cage-assisted anterior cervical discectomy and fusion at four levels: clinical and radiographic results
J Neurosurg Sci
(2008) - et al.
Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up
Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc
(2013) Iliac crest autograft versus alternative constructs for anterior cervical spine surgery: Pros, cons, and costs
Surg Neurol Int
(2012)- et al.
The aging of the global population: the changing epidemiology of disease and spinal disorders
Neurosurgery
(2015) - et al.
Functional and clinical outcomes following surgical treatment in patients with cervical spondylotic myelopathy: a prospective study of 81 cases
J Neurosurg Spine
(2011) - et al.
Subsidence of stand-alone cervical cages in anterior interbody fusion: warning
Eur Spine J Off Publ Eur Spine Soc Eur Spinal Deform Soc Eur Sect Cerv Spine Res Soc
(2003)