Measuring Dysphagia After ACDF Surgery Through A Novel Wearable Sensor

Dysphagia, dysphonia, and loss of cervical range of motion (ROM) are common complications after anterior cervical spine surgery, specifically anterior cervical discectomy and fusion (ACDF). Despite their clinical importance, studies on the treatment and/or prevention of these complications are limited due to the lack of valid and reliable outcome measures. The majority of research is found in the otolaryngology literature and has focused on disease pathophysiology, diagnosis, and therapy.

Dysphagia and dysphonia are widely measured by patient self-reported questionnaires, including the MD Anderson Dysphasia Inventory and SWAL-QOL. However, these validated outcome tools are cumbersome to complete and, therefore, have not been widely accepted into clinical practice, including in postoperative ACDF patients. The Bazaz score, a subjective questionnaire that has not been validated in the literature, has also been used to evaluate dysphagia after ACDF. Assessment using the Bazaz score is based on clinical examination, with the surgeon listening to the patient's voice and documenting hoarseness in the post-operative period. Recently, new patient-centered outcomes, the Eating Assessment Tool (EAT-10) and Voice Handicap Index (VHI-10) have been developed. Both EAT-10 and VHI-10 have excellent validity and reliability in evaluating dysphagia and dysphonia, respectively, in post-operative ACDF patients and can be used to document the initial dysphagia or dysphonia severity and monitor the treatment response in people with a wide array of swallowing and voice disorders. However, these methods of evaluating dysphagia and dysphonia alone offer limited information about the severity and characteristic of dysphagia or dysphonia and do not provide continuous monitoring of swallowing or speaking function throughout the post-operative period.

The wearable sensors under investigation in this study offer a novel, noninvasive, and easy-to-use way to monitor dysphagia, dysphonia, cervical ROM, and overall recovery progress in post-operative ACDF patients. Previous testing has demonstrated the ability of our sensors to monitor vital signs (including heart rate and respiratory rate), swallow count, talking time, energy expenditure, cervical neck movement, and body orientation. Sensor-measured swallow count and talking time, in conjunction with EAT-10 and VHI-10 scores, can provide a comprehensive view of the progression of dysphagia and dysphonia. Cervical neck movements measured by the sensor can enable continuous assessment of cervical ROM. Other general metrics captured by the sensors, including heart rate, respiratory rate, energy expenditure, and body orientation can provide other meaningful measures of recovery in post-operative ACDF patients. These sensors have also received positive feedback from patients and physicians on their comfort, ease of use, and application, further demonstrating the potential value of these sensors in improving the quality of post-operative care for ACDF patients.

Inclusion criteria

• Patients who have undergone anterior cervical discectomy and fusion (ACDF) for one or more levels for a diagnosis of cervical radiculopathy or myelopathy
• Scheduled to return to the MSK orthopaedic clinic for a post-operative appointment
• Aged between 18 to 88 years at time of surgery

Exclusion criteria

• Patients that underwent a revision of previous ACDF surgery at one or more operative levels
• Surgeries performed for a traumatic or oncologic etiology
• Members of vulnerable populations (i.e. prisoners, pregnant women)