The average age of patients diagnosed with spinal cord disease due to cervical disc herniation in this study was 52.62 ± 6.81 years, aligning with the anticipated pathogenesis of cervical spine degeneration. With increasing age, degenerative injuries such as disc herniation, bone spur formation, and progressive ossification can lead to cervical cord compression9. Males constituted nearly 2.5 times more cases than females, likely due to the heavier labor typically performed by males, potentially accelerating degeneration. The average onset time was 14.63 ± 4.51 weeks, with most cases initiating within 6 months, consistent with findings in other studies10,11. Trauma contributed to only 4.05% of cases, underscoring the predominant role of long-term spinal cord compression by static and dynamic factors in the pathogenesis of cervical cord disease.
Vietnam, being the country with the highest motorbike usage in Asia and reliant on manual labor due to limited industrialization and modernization, faces increased risks of spinal degeneration and accidents. The combination of high labor and living expenses often leads patients to seek medical attention late, resulting in numerous long-term sequelae of spinal cord injury.
The mean VAS score was 6.15 in our study, significantly improved from 6.15 at the time of onset to 2.35 at the time of final follow-up. Our results in 74 patients demonstrated the short-term outcome after ACDF surgery. No serious complications or side effects were observed in our patients. Almost all of the patients showed a clinically relevant degree of pain relief, with at least a three-point reduction in VAS for pain, representing a statistically significant reduction in mean pain intensity scores.
We also noted a trend toward better outcomes based on NDI. In terms of NDI, which indicated the level of disability, there were no severe patients post-operation after the twelve-month follow-ups. Most patients had a better quality of life and even returned to work. Narain et al. examined a cohort of patients undergoing ACDF and showed minimum clinically important difference achievement rates for VAS neck, VAS arm, and NDI of 55.4%, 36.9%, and 76.6%, respectively12. This further highlights that while patients may recover well in terms of their neck pain and disability, it is more difficult for them to achieve clinically significant improvement in arm pain. NDI decreased significantly after intervention up to 12 months compared to the post-procedural value. The Global Outcome for patient satisfaction was positive in 90.54% of patients. Evaluation of global outcome 12 months after the procedure was considered a positive response if the patient reported a decrease in pain and an improved ability to perform daily activities and if the patient introduced this treatment to other patients
In summarizing the results, NDI emerged as the most influential variable explaining the model, serving as a critical preoperative and outcome predictor for pain intensity and NDI. These findings highlight that a low disability based on NDI before surgery, especially at the short-term outcome, is a valuable predictor for a successful long-term outcome of ACDF. The preoperative NDI appears crucial in patient selection for ACDF, with high NDI at the short-term outcome indicating patients at risk who require further treatment and support3.
The study documented herniated discs ranging from 1 to 3 levels, with rates at 1 level, 2 levels, and 3 levels being 45.9%, 47.3%, and 6.8%, respectively. An anterior surgical approach is recommended for up to 3 surgical levels3.
Neurological function recovery, assessed by mJOA score, indicated an average preoperative score of 11.1 ± 0.41, improving to 11.7 ± 1.73 at discharge, with further enhancement to 13.6 ± 1.33 and 14.8 ± 1.29 after 6 to 12 months. While changes in Cobb angle and range of motion were not statistically significant, the neurological recovery rate after 12 months suggested a favorable outcome, with 86.5% achieving good to excellent recovery. The characteristics and prevalence of these pain and disability trajectories elucidate the outcomes to be anticipated following ACDF, providing valuable information to assist patients in establishing appropriate expectations for their recovery13.
The predominant postoperative complications observed in this study were neck pain (24.3%) and dysphagia (8.1%), which are typical in anterior cervical spine surgery due to intubation. The incidence of dysphagia after ACDF in our study was 3.3%, consistent with findings in several other large database studies. However, the reported incidence in the literature varies widely due to a lack of standardized criteria and variations in study design. In a systematic review of primarily prospective cohort studies, Riley et al. reported dysphagia rates ranging from 1–79% within the first week (mean, 33%), decreasing to 13–21% (mean, 16.8%) one year after surgery. The dysphagia incidence may result from multiple factors. As more literature becomes available regarding the development of postoperative dysphagia after ACDF, treating physicians may become more vigilant in identifying and reporting this complication14.
The comorbidity burden in ACDF procedures has increased over time. The study identified several comorbidities as independent risk factors for dysphagia, including smoking, fluid and electrolyte disorders, paralysis, coagulopathy, neurodegenerative diseases, alcohol abuse, diabetes with chronic complications, depression, and psychosis. In contrast to some studies on obesity, our results demonstrated that body mass index was significantly associated with dysphagia. Similarly, Wang et al. and Liu et al. found increased rates only in the immediate postoperative period. The authors suggested that the association between obesity and early dysphagia may be linked to the increased thickness of prevertebral tissue in obese patients, leading to difficulty in manipulation and excessive esophageal retraction. The study reported a hematoma in one case, promptly addressed through ultrasound evaluation and re-operation. Another patient experienced postoperative infection, successfully treated with antibiotics without the need for re-operation13–15.
Based on multivariable logistic regression analysis, several factors including age > 50 years old, hypertension, diabetes, and more level fusions were identified as significant independent risk factors for the development of postoperative dysphagia after surgery. Patient age, an unmodifiable factor, along with controllable internal medical conditions such as hypertension and diabetes, significantly influence the body’s postoperative inflammatory response. Effective management of these conditions is imperative before surgery. An increase in the number of surgical levels and duration of surgery escalates the extent of soft tissue damage. Therefore, surgeons need to devise efficient surgical strategies to minimize operative time and reduce soft tissue injury.
Several limitations exist in our study, including the absence of long-term follow-up information. The database lacks details on specific levels of treatment, readmission rates, previous procedures, medical management, and outpatient procedures. Additionally, the study lacks information about the type of hardware used in the procedures. With a sample size as large as in this study, statistically significant differences may be identified but remain challenging to interpret clinically, especially if their odds ratio (OR) remains close to 1.