Complete and incomplete recurrent laryngeal nerve injury after thyroid and parathyroid surgery: Characterizing paralysis and paresis.

BACKGROUND: Injury of the recurrent laryngeal nerve and consequent disorder of vocal fold movement is a typical complication in thyroid and parathyroid surgery. During postoperative laryngoscopy we observed not only a complete standstill (vocal fold paralysis), but also a hypomobility (paresis). In this prospective study, we investigated the difference in incidence and prognosis as well as risk-factors, intraoperative neuromonitoring, and symptoms between vocal fold paralysis and vocal fold paresis. METHODS: Data were prospectively collected and analyzed in a single high-volume thyroid center between 2012 and 2016. Vocal fold paresis was defined as hypomobility in abduction or adduction, a reduction in range and speed of vocal fold movement. Vocal fold paralysis was defined as asymmetry and missing purposeful vocal fold movement. RESULTS: The study included 4,707 surgeries and 7,992 at-risk nerves at risk. Vocal fold paralysis was diagnosed in 374 patients (4.68% of 7,992 nerves at risk) and vocal fold paresis in 114 patients (1.43%). Exclusively in the paralysis group, 36 patients (0.45%) developed permanent loss of vocal fold function (P < .001). In follow-up, vocal fold paresis patients regain normal vocal fold function significantly earlier than vocal fold paralysis (mean duration: 6.96 ± 6.506 vs 10.77 ± 7,827 weeks) and presented with significantly less symptoms like hoarseness, diplophonia, dysphagia, and dyspnea (68.8% vs 95.9 %). In intraoperative neuromonitoring, vocal fold paresis showed a significantly higher postresectional N. vagus amplitude than vocal fold paralysis patients (0.349 mV vs 0.114 mV, P < .001). CONCLUSION: After thyroidectomy, vocal fold paresis must be distinguished from vocal fold paralysis and should be implemented as a separate outcome parameter in the postoperative quality assessment.

Pharyngolaryngectomy with free jejunal autograft reconstruction and tracheoesophageal voice restoration: Indications for replacements, microbial colonization, and indwelling times of the Provox 2 voice prostheses.

BACKGROUND: The purpose of this prospective study was to investigate shunt-related and device-related complications and microbial colonization of voice prostheses in patients after pharyngolaryngectomy with jejunal autograft reconstruction in comparison to patients after standard laryngectomy. METHODS: Nine patients after pharyngolaryngectomy with jejunal autograft reconstruction (group 1) and 14 patients after standard laryngectomy (group 2) equipped with the Provox(®) 2 voice prostheses were followed up over 2 years. Anamnestic data, documentation of shunt-related or device-related complications, the Provox(®) 2 indwelling time, and standard microbiological procedures of voice prostheses were used for analyses. RESULTS: A total of 157 prostheses were replaced. No significant difference in mean prosthesis indwelling time (p = .45) was observed between group 1 (116 ± 114 days) and group 2 (129 ± 99 days). Patients with jejunal autograft reconstruction needed prosthesis replacements more frequently within the first 60 days after prosthesis insertion in comparison to patients after standard laryngectomy (p = .007). The main indication for replacement in both groups was the device leakage (group 1: 93.1%, group 2: 92.1%). Prostheses of group 1 were more often colonized with Staphylococcus aureus (p = .027) and Enterobacteriaceae (p = .015). CONCLUSION: This study demonstrated that, in comparison with patients after standard laryngectomy, patients after jejunal autograft reconstruction have similar shunt-related and device-related complications and prosthesis indwelling times. Therefore, tracheoesophageal voice rehabilitation could be strongly recommended in these patients.

Comparison of biofilm formation on new Phonax and Provox 2 voice prostheses - a pilot study.

BACKGROUND: In voice rehabilitation for laryngectomized patients, voice prosthetic biofilm formation is still an unsolved problem. Design and materials of voice prostheses have been altered by manufacturers to improve function and extend the lifetime of devices. The goal of the study was to investigate biofilm formation on Provox 2 and Phonax, recently introduced voice prostheses made of thermoplastic polyurethane. METHODS: Five laryngectomized patients were equipped with both Phonax and Provox 2 voice prostheses. Microbial colonization was analyzed using standard microbiological methods. Biofilm formation and material infiltration were illustrated using scanning electron microscopy, fluorescence microscopy, and thin-section light microscopy. RESULTS: Although no differences in quality or quantity of microbial colonization were assessed, microscopic imaging revealed differences in material surfaces, biofilm composition, and infiltration morphologies; the polyurethane material seems to destabilize biofilm architecture by inhibition of hypheal Candida growth forms. CONCLUSIONS: Polyurethane material for voice prostheses seems to reduce biofilm stability and infiltrative processes.