Recurrent Laryngeal Nerve Palsy after Anterior Cervical Discectomy and Fusion - Prevalence and Risk Factors

Diagnosis and treatment of postoperative voice complications following anterior cervical discectomy and fusion: a systematic review

BACKGROUND

There is a wide discrepancy in the literature regarding the incidence of postoperative dysphonia following ACDF. How postoperative dysphonia is measured is also inconsistent, with many studies relying on patient-reported outcomes rather than diagnostic laryngoscopy. The purpose of this study was to consolidate information regarding dysphonia after ACDF to improve diagnosis and management.

METHODS

A comprehensive database search was performed using key terms. Inclusion criteria was as follows: published within 10 years, subjects > 18 years of age, ACDF for treatment of cervical radiculopathy and/or myelopathy, reports of postoperative changes in voice, and at least one postoperative follow-up between one week and six months. Works that included endoscopic surgical techniques and/or subjects with a history of cancer or trauma to the operated region were excluded. Reviews and meta-analyses were also removed from analysis.

RESULTS

Twenty-one eligible studies were analyzed. Evaluation methods varied, with incidence rates ranging from 0.3 to 27%. Symptoms typically arose within one week post-op, persisting up to one year. Treatment modalities included steroids, speech therapy, and laryngoplasty. Mechanisms included recurrent laryngeal nerve injury, endotracheal tube pressure, and postoperative edema.

CONCLUSIONS

Postoperative voice complications following ACDF represent a clinically significant outcome that can impact a patient's quality of life. Patients should be counseled preoperatively about the potential risk, and managed postoperatively to mitigate long-term impairments. Involvement of otolaryngologists may help prevent these complications or allow for early detection and management, underscoring the importance of multidisciplinary care in optimizing surgical outcomes.

Machine learning models for predicting dysphonia following anterior cervical discectomy and fusion: a Swedish Registry Study

BACKGROUND

Dysphonia is one of the more common complications following anterior cervical discectomy and fusion (ACDF). ACDF is the gold standard for treating degenerative cervical spine disorders, and identifying high-risk patients is therefore crucial.

PURPOSE

This study aimed to evaluate different machine learning models to predict persistent dysphonia after ACDF.

STUDY DESIGN

A retrospective review of the nationwide Swedish spine registry (Swespine).

PATIENT SAMPLE

All adults in the Swespine registry who underwent elective ACDF between 2006 and 2020.

OUTCOME MEASURES

The primary outcome was self-reported dysphonia lasting at least 1 month after surgery. Predictive performance was assessed using discrimination and calibration metrics.

METHODS

Patients with missing dysphonia data at the 1-year follow-up were excluded. Data preprocessing involved one-hot encoding categorical variables, scaling continuous variables, and imputing missing values. Four machine learning models (logistic regression, random forest (RF), gradient boosting, K-nearest neighbor) were employed. The models were trained and tested using an 80:20 data split and 5-fold cross-validation, with performance metrics guiding the selection of the best model for predicting persistent dysphonia.

RESULTS

In total, 2,708 were included in the study. Twelve key predictors were identified. Four machine learning models were tested, with the RF model achieving the best performance (AUC=0.794). The most significant predictors across models included preoperative NDI, EQ5Dindex, preoperative neurology, number of operated levels, and use of a fusion cage. The RF model, chosen for its superior performance, showed high sensitivity and consistent accuracy, but a low specificity and positive predictive value.

CONCLUSIONS

In this study, machine learning models were employed to identify predictors of persistent dysphonia following ACDF. Among the models tested, the RF classifier demonstrated superior performance, with an AUC value of 0.790. The RF model identified NDI, EQ5Dindex, and number of fused vertebrae as key variables. These findings underscore the potential of machine learning models in identifying patients at increased risk for dysphonia persisting for more than 1 month after surgery.

Recurrent Laryngeal Nerve Injury During Anterior Cervical Discectomy and Fusion (ACDF): A Case Presentation and Review of the Literature

Anterior cervical discectomy and fusion (ACDF) is a surgical procedure used to manage spine pathology including disc herniation, spondylosis, and myelopathy. During the operation, the vertebral segment of interest is accessed via the anterior neck and the disc space is fully resected along with osteophytes to relieve the compression along the affected nerve. While the procedure is regarded as being highly effective in improving symptoms, there are several complications associated with the surgery that patients should be cautioned about. We present a case of a patient with oropharyngeal and cervical esophageal dysphagia and left vocal cord paralysis following a C5/C6, C6/C7, and C7/T1 ACDF for multilevel cervical stenosis and disc herniation. Otolaryngology evaluation confirmed vocal cord paralysis from recurrent laryngeal nerve palsy (RLNP) and the patient's symptoms were managed with a vocal cord injection and speech therapy. This report explores the surgical approach for ACDF along with its complications and postoperative care.

A systematic review of risk factors and adverse outcomes associated with anterior cervical discectomy and fusion surgery over the past decade

Background

Anterior cervical discectomy and fusion (ACDF) is one of the most frequently performed cervical surgeries in the world, yet there have been several reported complications.

Objective

To determine the actual incidence of complications related to ACDF as well as any risk variables that may have been identified in earlier research.

Methods

To evaluate the origin, presentation, natural history, and management of the risks and the complications, we conducted a thorough assessment of the pertinent literature. An evaluation of clinical trials and case studies of patients who experienced one or more complications following ACDF surgery was done using a PubMed, Cochrane Library, and Google Scholar search. Studies involving adult human subjects that were written in the English language and published between 2012 and 2022 were included in the search. The search yielded 79 studies meeting our criteria.

Results

The overall rates of complications were as follows: Dysphagia 7.9%, psudarthrosis 5.8%, adjacent segment disease (ASD) 8.8%, esophageal perforations (EPs) 0.5%, graft or hardware failure 2.2%, infection 0.3%, recurrent laryngeal nerve palsy 1.7%, cerebrospinal fluid leak 0.8%, Horner syndrome 0.5%, hematoma 0.8%, and C5 palsy 1.9%.

Conclusion

Results showed that dysphagia was a common postoperative sequelae with bone morphogenetic protein use and a higher number of surgical levels being the major risk factors. Pseudarthrosis rates varied depending on the factors such as asymptomatic radiographic graft sinking, neck pain, or radiculopathy necessitating revision surgery. The incidence of ASD indicated no data to support anterior cervical plating as more effective than standalone ACDF. EP was rare but frequently fatal, with no correlation found between patient age, sex, body mass index, operation time, or number of levels.

Critical analysis of the evaluation of postoperative dysphagia following an anterior cervical discectomy and fusion

BACKGROUND AND PURPOSE

Postoperative dysphagia is a known complication of anterior cervical discectomy and fusion (ACDF) with reported incidences ranging from 1 to 79%. No standardized guidelines exist for spine surgeons to evaluate postoperative dysphagia after ACDF. A systematic method may be beneficial in distinguishing transient postoperative dysphagia secondary to intubation from those with postoperative complications. This study evaluates the causes, recognition, and clinical evaluation of postoperative dysphagia following ACDF.

METHODS

International classification of disease (ICD) and current procedural terminology (CPT) codes were used to identify ACDF patients and compared to anterior lumbar discectomy and fusion (ALDF), serving as a control group, between the years 2015-2019 and those diagnosed with dysphagia within 1 year. Demographics, operative details, and clinical evaluation were reviewed. Exclusion criteria included history of head and neck procedures, cancer, stroke, radiation, and trauma.

RESULTS

One hundred thirty-one ACDF and 93 ALDF patients met inclusion criteria. Twenty-seven (20.6%) ACDF patients were diagnosed with dysphagia within 1 year. Less than half of the dysphagia patients had the word "dysphagia" documented in their 1-month spine surgeon follow up visit. Only 66% of dysphagia patients had specialist evaluation and one third of those patients were referred by their surgeon. Only six patients received diagnostic barium swallow evaluations.

CONCLUSION

Postoperative dysphagia risk increases in ACDF compared to ALDF, likely due to underlying anatomy. Postoperative dysphagia symptoms are not effectively documented by spine surgeons and as a result underevaluated by dysphagia specialists. Patients may benefit from more extensive pre- and post-operative screening, evaluation, and referral regarding dysphagia symptoms following ACDF.