Anterior cervical fusion was first described by Smith and Robinson in 1958 for treating cervical spondylodiscoarthrosis.1 The anterior approach allows treating several conditions, particularly those related to spondylodiscoarthrosis.8 Classically, this approach has been performed with plates and screws, and Zero-profile implants are a relatively recent surgical option with lower complication rates.3,9
A plethora of complications of anterior cervical fusion with varying prevalence rates have been reported in the literature, including dysphagia, recurrent laryngeal nerve palsy, esophageal or laryngeal laceration, Horner syndrome, thoracic duct injury, pneumothorax, vessel injuries (vertebral artery, carotid artery, or jugular vein), epidural hematoma, epidural abscess, surgical-site hematoma, spondylodiscitis, seroma, dural fistula, meningitis, spinal cord contusion, nerve root injury, worsening of radicular or myelopathic symptoms, displacement of surgical materials, and postoperative mechanical instability of the cervical spine.10−30
In a retrospective study, Fountas et al.31 evaluated complications in 1,015 consecutive patients who underwent anterior cervical fusion; the most common complications included isolated dysphagia (9.5%) and surgical-site hematoma (5.6%). Dysphagia improved completely within 7 days in most patients. The number of operated levels was considered a risk factor for dysphagia, and the rate of complications was higher in surgeries involving 3 or more levels. In addition, there was accidental esophageal perforation in 0.3% cases and worsening of pre-existing myelopathic symptoms in 0.2% cases.
Starmer et al.2 performed a comprehensive review, the largest in the literature, involving 1,649,871 patients who underwent anterior cervical fusion and found that postoperative dysphagia occurred in 2% cases. Dysphagia was more common in patients > 65 years of age and was associated with dysphonia, unilateral vocal cord paralysis, and aspiration pneumonia.
Overley et al.32 performed a retrospective cohort study including 80 patients who underwent anterior cervical fusion and compared the use of stand-alone cages (n = 40) and cervical plates (n = 40). Patients who received cages developed no complications (0/40), whereas 10% (4/40) patients who received plates developed complications. There were 3 cases of dysphagia. Myelopathic symptoms occurred predominantly compared with radicular symptoms in both groups, which contradicts the findings in our case series.
The classical risk factors for dysphagia following anterior cervical fusion include older age, increased peroperative time, multiple operated levels, and reoperations.33−38
Liu et al.39 performed a systematic review of 59 studies and proposed identifying risk factors for immediate postoperative dysphagia following anterior cervical fusion. The modifiable risk factors for dysphagia were: prolonged peroperative time, use of orotracheal tube pilot balloon filled with a pressure > 20 mmHg, use of plates and screws, smoking, history of psychiatric disorders, angle at C2–C7, prevertebral tissue edema, and recurrent laryngeal nerve palsy. Non-modifiable risk factors for dysphagia were: older age, female sex, higher number of operated levels, reoperations, prolonged duration of preoperative pain, and arthrodesis at higher levels. The study concluded that Zero-profile implants reduce the prevalence of dysphagia compared with plates and screws.
Recently, Yang et al.40 performed a meta-analysis of 30 studies on arthrodesis using Zero-profile implants and showed that the prevalence of postoperative dysphagia ranged from 0–76% and the rate of persistent dysphagia ranged from 0–7%. Furthermore, the prevalence of this complication increased with the number of operated levels.
Yin et al.3 performed another meta-analysis and literature review and confirmed that the prevalence of dysphagia decreased using Zero-profile implants compared with that using plates and screws, particularly in the first 3 months following surgery.
In our series of 193 patients consecutively treated with Zero-profile implants at a single center, the rate of dysphagia was 9.3% in the immediate postoperative period. The risk factors for this complication were advanced age and increased number of operated levels.
The present study has some limitations. First, the study was retrospective through the analysis of medical records. Second, the study was conducted at a single center and surgeries were performed by 4 distinct surgeons, although the surgical technique was similar. Finally, complications were assessed only during the hospitalization period and subsequent follow-up of the patients was not included in this study.