Enhancing Voice and Swallowing: A Cross-Sectional Study on Percutaneous Injection Medialisation Laryngoplasty Outcomes in Patients of Unilateral Vocal Cord Palsy

Abstract

Unilateral vocal cord palsy (UVCP) is a condition that significantly impacts voice quality and swallowing function, leading to considerable challenges in communication and nutrition. Percutaneous Injection Medialisation laryngoplasty (PIML) has emerged as a pivotal intervention to restore vocal cord function in affected patients. To evaluate the vocal and swallowing outcomes in cases of unilateral vocal cord palsy by PIML based on vocal and swallowing parameters. A cross-sectional analytical study was conducted at tertiary care hospital among 40 adult patients of UVCP without structural lesion of larynx and were treated with PIML using hyaluronic acid. Vocal and swallowing parameters were measured prior to procedure and post procedure at 2 h, 3 month and 6 month. Subjective parameter like VHI-30 and objective parameters were measured by using (1) Acoustic analysis (2) Perceptual Evaluation by GRBAS, (3) Aerodynamic analysis by Mean phonation time (MPT). Swallowing outcome measured by using Penetration-Aspiration scale (PAS) on Functional Endoscopic Evaluation of Swallowing (FEES). 40 patients with UVCP treated with injection laryngoplasty under LA. There was significant decrease in VHI (by 32.05 points, p < 0.05), GRBAS (by 5.35 points, p 0.05), Jitter (by 0.63 points, p < 0.05), Shimmer (by 2.34 points, p < 0.05) and Penetration aspiration score (by 1.8 points, p < 0.05) noted 2 h post procedure and this effect maintained till 6 month of follow up. There was significant increase in MPT (by 7.2 seconds, p < 0.05) and HN Ratio (by 6.22 points, p < 0.05) noted 2 h post procedure and this effect maintained till 6 month of follow up. All patients (100%) achieved statistical improvement in both voice and swallowing parameter after injection laryngoplasty and this improvement maintained till 6 months. Out of the total 40 cases, 6 (15%) cases of malignancies could not survive the study duration because of primary illness, 06 (15%) cases recovered spontaneously, 24 (60%) cases were not recovered but compensated by opposite vocal cord. A total of 04 (10%) cases required medialization thyroplasty in view of progressive deterioration of benefit. Average duration of benefit was 6 month and there was no major complication noted. Early percutaneous injection medialisation laryngoplasty is a safe and effective procedure in patients with UVCP with evidence of significant long-lasting improvement in voice and swallowing.

Introduction

Voice is essential to exercise the power of communication and its disorder may have mental, physical, emotional and communication repercussions and thus may impact the quality of life. Vocal cords play two main functions- phonation and protection of lower airways. The primary innervation to the vocal cords comes from the branches of the vagus nerve (superior and inferior laryngeal nerves). Inferior laryngeal nerve is better known as the recurrent laryngeal nerve due to its unique course underneath the arch of the aorta on the left side and underneath the subclavian artery on the right side. It supplies all motor and sensory innervation below the vocal cord [1, 2].

Vocal cord palsy or paresis can be caused by any pathology of vocal fold itself (tumour or scarring) or any pathology which interferes the normal function of vagus nerve or its branches e.g. idiopathic, iatrogenic, malignancy or metastasis, central neurologic problem (stroke, tumour, multiple sclerosis), non-surgical trauma or systemic problems (amyotrophic lateral sclerosis or Guillain barre syndrome) [3]. Studies have reported incidence of vocal cord palsy to be 0.42%, affecting majority of patients in 5th and 6th decades (77.2%) with males to females in the ratio of 3:1. Hoarseness is most common symptom of vocal cord paralysis (83.6%) [4]. Incidence of VCP is increasing due to more and more patients undergoing surgical procedure particular to head & neck region [5, 6].

Unilateral vocal cord palsy (UVCP) presents with dysphonia, shortness of breath, swallowing difficulties, along with poor exercise tolerance, despite the normal lung function [7]. Complete recovery is anticipated if the nerve injury is transient. However, if the injury is severe, complete conduction block develops and leads to impaired recovery. Initially conservative management techniques are preferred: speech therapy, pushing exercise, electrical stimulation and swallowing therapy [8]. If satisfactory results are not achieved, then surgical management of UVCP can be done, with four main ways: (1) Injection laryngoplasty (2) Medialization thyroplasty (3) Arytenoid adduction and (4) Laryngeal reinnervation [9]. The goal of the treatment of the UVCP is to address the underlying cause and improve or eliminate the functional deficits in voice, swallowing and airway protective reflexes.

PIML is unique procedure, as it can be performed in an office setting/ bedside with minimal invasion and thus makes it preferred intervention. The first Injection laryngoplasty was reported by Dr Bruening in 1911 using liquid paraffin which was not compatible and led to granuloma formation [10]. Currently, a variety of synthetic injectable materials have been tested including the calcium hydroxyapatite, hyaluronic acid, autologous fat, collagen-based products, autologous fascia etc [9]. Further, PIML is less time consuming and cost-effective technique which is simpler and requires shorter learning time [11]. Therefore, this study aims to systematically evaluate the outcomes of PIML in improving vocal and swallowing abilities among individuals with UVCP. By employing a cross-sectional analytical approach, we seek to provide insights into the effectiveness of this treatment, ultimately contributing to enhanced quality of life for those affected.

Material & Methods

A cross-sectional analytical study was conducted at the department of ENT-HNS, from July 2022 to Dec 2023 at tertiary-level hospital of North India, after clearance by Institutional Ethics Committee. The objective of the study was to evaluate the vocal and swallowing outcomes by management of UVCP by PIML. It being a pilot study, included 40 consecutive patients of UVCP without structural abnormality or lesion of vocal cords. UVCP caused due to injury to RLN, malignancy of thyroid, lungs, oesophagus without infiltration into larynx were included. Patients with malignancy of larynx/hypopharynx invading into vocal folds, previous history of undergoing laryngoplasty, patients with systemic illness like stroke, Parkinsonism, motor neuron disease were excluded.

All patients, after obtaining written and informed consent underwent videolaryngoscopic examination either by 70-degree Hopkins rod lens or flexible fibreoptic laryngoscopy (FOL).

Voice Analysis

The baseline voice (subjective and objective) parameter of patients assessed prior to PIML and same parameter were assessed after 2 h, 3 months and 6 months post procedure. Subjective assessment by patient was done using the Voice Handicap Index (VHI-30) questionnaire and the objective assessment was done by Acoustic analysis using Dr speech software, Aerodynamic analysis using MPT and Perceptual evaluation using GRBAS scale.

The patients were given a questionnaire containing 30 questions with 3 categories which include 10 functional, physical and emotional questions in each category. Patients were asked to give their responses using a score from 0 to 4. Total score obtained was used as VHI.

The recordings for acoustic analysis were made with the professional microphone. The subjects were assessed for acoustic analysis in sitting position at 15 cm mouth to microphone distance. The recorded voice was assessed to measure the fundamental frequency (F0), jitter, shimmer, harmonic-to-noise ratio (HNR). Maximum phonation time (MPT) was measured by asking subject to take a deep breath and then to sustain the vowel sound ‘ah’ for as long as possible at a comfortable pitch and loudness on one exhalation without straining. Using a stopwatch, duration (in seconds) was recorded. This step is repeated and recorded for three times. Out of these 3 attempts the longest duration is considered MPT.

Auditory perceptual evaluation of voice was done using GRBAS scale with 5 parameters: overall Grade or severity (G), Roughness of voice (R), Breathiness (B), Asthenia (A), and Strain (S). The quality of each parameter of voice was given a scoring of 0 to 3. An overall GRBAS score was obtained.

Swallowing Analysis

Swallowing outcome was measured with the help of Fibreoptic endoscopic evaluation of swallowing (FEES) using Penetration-Aspiration scale (PAS). The parameter of patients first assessed prior to PIML and same parameter were assessed after 2 h, 3 month and 6-month post procedure. The patient was seated upright on a chair, nasogastric tube if present was removed. The test diets included 5 mL aliquots of milk dyed with food color was used. The images were recorded at 30 frames per second. A clinician observed the swallowing process, signs of aspiration and residue. The findings were reported on the basis of Penetration-aspiration score (PAS) (Fig. 1).

Fig. 1.

Functional Endoscopic evaluation of swallowing using milk dyed with food color

Technique of Percutaneous Injection Medialisation Thyroplasty

After written-informed consent, patient in upright position, under aseptic conditions; local infiltration using 2% lignocaine were injected into neck around cricothyroid membrane region or thyrohyoid membrane region depending upon the direction of entry into larynx for PIML. 4% lignocaine was sprinkled over mucosal surface of vocal cords with the help of fibreoptic laryngoscope. A transcutaneous intratracheal injection of 4% lignocaine was also administered and patient was asked to cough so that 4% lignocaine is dispersed over the mucosa of trachea and undersurface of vocal cords. Under fibreoptic guidance, using 25- gauge needle 1 ml of hyaluronic acid (23 mg/ml) were injected lateral to contact surface of vocal fold deep into thyroarytenoid muscle (Fig. 2).

Fig. 2.

PIML procedure representing needle in sub glottis by thyrohyoid membrane approach

Approach for PIML was either via cricothyroid membrane or thyrohyoid membrane. Cricothyroid membrane approach was used in 34 (85%) cases, where in needle was bent by around 45 degrees 1.5 cm from its tip. For 6 (15%) cases thyro-hyoid membrane approach was used, where in needle was bent at two places, so that needle tip can reach thyroarytenoid muscle.

All patients were subjected to voice and swallowing therapy in post procedure period. Therefore, there was no control arm to compare only PIML versus PIML with voice & swallowing therapy or only voice & swallowing therapy.

Statistical analysis was performed with wilcoxon signed rank test for pre and post injection laryngoplasty subjective & objective parameters. The categorical variables were assessed using Chi Square test of significance. Results were graphically represented where deemed necessary. For statistical significance, p-value of less than 0.05 was considered statistically significant. Statistical analysis was performed using the SPSS ver 25.0 (IBM Corp, Chicago, USA).

Results

40 patients who underwent PIML at ENT OPD for UVCP, were evaluated for voice and swallowing parameters. Demographic data, age bracket, symptoms, laterality and aetiology of UVCP is illustrated in Table 1. Mean age of the cases 47.9 years with range of 12 to 72 years, majority of cases between 41 and 60 years (40%). Out of the total 40 cases of UVCP, 32(80%) cases were males and 08 (20%) were females. Common symptoms of UVCP included hoarseness (100%) followed by hoarseness along with aspiration (77.50%). Majority of cases 31 (77.50%) has Left sided palsy while 9 (22.5%) cases has right sided palsy. Most common aetiology of UVCP was iatrogenic (40%) followed by idiopathic (30%), neoplasm (20%), and laryngo-tracheal trauma (10%).

Table 1.

Patient characteristics and aetiology of vocal cord palsy

Characteristics	Number
Gender
Male	32 (80.0%)
Female	08 (20.0%)
Age (in years)
0 - 20 yrs	2 (5%)
20- 40 yrs	10 (25%)
40- 60 yrs	16 (40%)
>60 yrs	12 (30%)
Range	12-72 yrs
Mean	47.9 yrs
Symptoms
Hoarseness	40 (100%)
Hoarseness with aspiration	31 (77.5%)
Side of vocal cord palsy
Right	09 (22.5%)
Left	31 (77.5%)
Aetiology
Iatrogenic	16 (40%)
Esophagectomy	5 (12.5%)
Thyroidectomy	4 (10%)
Cardiac surgery	4 (10%)
Vagal Schwannoma excision	1 (2.5%)
Glomus Jugulare excision	1 (2.5%)
Giant Branchial cyst with retrosternal extension	1 (2.5%)
Idiopathic	12 (30%)
Neoplasm	10 (25%)
Lung carcinoma	6 (15%)
Thyroid cancer	2 (5%)
Oesophageal cancer	2 (5%)
Laryngo-tracheal trauma	2 (5%)

Time duration from onset of symptoms to first visit to OPD was also recorded. Majority of patient 18(45%) were referred/ reported within 0–7 days (mean 03 days), followed by 10(25%) within 8–14 days (mean 10.6 days) and 12(30%) after 14 days (mean 22.75 days). The earliest intervention was done in patients with RLN palsy due to surgical or non-surgical trauma.

Vocal and swallowing parameters were respectively assessed and compared with baseline.

Subjective Analysis

A significant decrease of 37.05% in VHI was seen 2 h post Injection laryngoplasty (86.5 to 54.45, p value  <  0.001) which further decrease to 45.20(p-0.01) by the end of 3 months. The difference between 3 and 6 months was non-significant (49.79; p-0.221) (Table 2).

Table 2.

Subjective analysis at baseline and follow up

VHI	Time period
	Baseline	2 h	3 months	6 months*
Number	40	40	40	28
Mean	86.50	54.45	45.20	49.79
SD	12.99	12.70	19.78	18.31

p-value (from baseline to 2 h, baseline to 3 months, baseline to 6 months) < 0.05 Significant

p-value (from 2 h to 3 month, 3 month to 6 month)- Not Significant

* 6 mortalities & * 6 complete recovery

Perceptual Evaluation

Baseline GRBAS score was recorded and compared with post procedure GRBAS score. At, 2 h post procedure GRBAS showed a significant fall of 48% (p value  <  0.05). This significant decrease maintained till 6 months. However, comparison among post procedure groups (2 h to 3 months, 3 months to 6 months) was not found significant (Table 3).

Table 3.

Perceptual evaluation at baseline and follow up

GRBAS	Time period
	Baseline	2 h	3 months	6 months*
Number	40	40	40	28
Mean	11.15	5.80	4.90	4.85
SD	1.95	2.14	2.90	2.50

p-value (from baseline to 2 h, baseline to 3 months, baseline to 6 months) < 0.05 Significant

p-value (from 2 h to 3 month, 3 month to 6 month)- Not Significant

* 6 mortalities & * 6 complete recovery

Aerodynamic Analysis

A significant increase of 51.2% in MPT from Baseline (6.8 s) to 2 h after Injection laryngoplasty (14.0 s) (p  <  0.05) and this improvement maintained till 6 months (MPT − 15.43). However, comparison among post procedure groups (2 h to 3-month, 3-month to 6-month) was not found significant (Table 4).

Table 4.

Aerodynamic analysis at baseline and follow up

MPT	Time period
	Baseline	2 h	3 months	6 months*
Number	40	40	40	28
Mean	6.80	14.00	15.55	15.43
SD	3.61	5.89	7.16	7.75

p-value (from baseline to 2 h, baseline to 3 months, baseline to 6 months) < 0.05 Significant

p-value (from 2 h to 3 month, 3 month to 6 month)- Not Significant

* 6 mortalities & * 6 complete recovery

Acoustic Analysis

Jitter and shimmer shows significant decreased after Injection laryngoplasty (p  <  0.05) and the decrease maintained till 6 months. However, comparison among post procedure groups (2 h to 3-month, 3-month to 6-month) were not significant. HNR was 11.28 at baseline, which increased significantly to 17.5 after Injection laryngoplasty (p  <  0.05). The difference was significantly maintained till 6 months. P value was not significant in case of fundamental frequency (Table 5).

Table 5.

Mean acoustic parameters comparison at different follow up duration

Parameter	Time	N	Mean	SD	p- value
Fundamental Frequency	Baseline	40	167.65	50.23	0.131
	2 h	40	149.53	50.64
	3 months	40	149.66	45.18	0.274
	6 months*	28	142.08	28.30	0.745
Jitter	Baseline	40	1.31	0.61	< 0.001
	2 h	40	0.68	0.44
	3 months	40	0.57	0.38	0.965
	6 months*	28	0.61	0.33	0.99
Shimmer	Baseline	40	4.86	2.66	< 0.001
	2 h	40	2.52	1.64
	3 months	40	2.11	1.20	0.584
	6 months*	28	2.52	1.69	0.587
Harmonic: Noise ratio	Baseline	40	11.28	2.34	< 0.001
	2 h	40	17.50	3.39
	3 months	40	17.92	3.92	0.212
	6 months*	28	18.25	3.12	0.645

* 6 mortalities & * 6 complete recovery

Swallowing Outcome Analysis

A significant improvement of 47.4% of PAS following injection laryngoplasty from baseline to 2 h (p  <  0.05). Improvement maintained till 6-month. However, p- value from 2 h to 3-month and 3-month to 6-month was not found significant (Table 6).

Table 6.

Penetration aspiration score at baseline and follow up

Penetration Aspiration scale	Time period
	Baseline	2 h	3 months	6* Months
Number	40	40	40	28
Mean	3.8	2.0	2.0	2.35
SD	1.88	0.85	0.85	1.18

p-value (from baseline to 2 h, baseline to 3 months, baseline to 6 months) < 0.05 Significant

p-value (from 2 h to 3 month, 3 month to 6 month)- Not Significant

* 6 mortalities & * 6 complete recovery

In present study, out of the total 40 cases, 6 cases (15.0%) of malignancies couldn’t survive the 6 months duration of follow up, 06 cases (15.0%) vocal cord function recovered spontaneously with mean duration of recovery being 05 months ranging from 4 to 6 months, in 24 cases (60.0%) partial or no recovery was noticed however, compensated well by opposite vocal cord, therefore no surgical intervention was performed. A total of 4 cases (10%) required Medialisation Thyroplasty (Fig. 3).

Fig. 3.

Final outcome of PIML

Discussion

Unilateral Vocal cord palsy is generally not a disease by itself but it is a consequence of pathology related to vagal nerve and its branches. Data on aetiology obtained from 1985 to 1995 in one a large case series [12], showed cancer to be the most common cause of UVCP. This shifted to Iatrogenic surgical injury (37%) from 1996 to 2005, with non-thyroid procedures (66%) surpassing thyroidectomy (33%) as the most common mode of injury. A study on 121 patients noted mean age of presentation was 46.52 years and aetiology being idiopathic 42.1%, surgical trauma (Iatrogenic) 22.3%, nonsurgical trauma 6.61%, malignancy 6.61%, and other benign lesions 9.09% as major causes [13]. Our study revealed mean age as 47.9 years with majority cases between 41 and 60 years (40%) of age affecting males (80%) than females (20%) and similar aetiological factors as mentioned in Table 1.

A study showed the most common symptom of unilateral vocal cord palsy was voice change in 98.21% and voice change with aspiration symptoms in 66% [14]. In our study, common symptoms of unilateral vocal cord palsy included hoarseness (100%) and hoarseness along with aspiration (77.50%).

Several studies have mentioned about left side vocal cord palsy preponderance [8, 13, 15]. Our study also showed that 31 (77.50%) patients had left sided vocal cord palsy while 09 (22.50%) has right vocal cord palsy. This is probably due to the increased vulnerability of left nerve due to the longer course.

The prognosis of UVCP is difficult to predict. Laryngeal electromyography is a good predictor of poor recovery for UVCP, but accuracy of prediction for complete recovery is only 12.8%. It is difficult to predict whether and when will UVCP recover, so management of UVCP should be focused to reduce patients’ discomfort and related complication [16, 17]. Several authors, including our study, have suggested that early intervention for acute UVCP leads to improved patient outcomes and quality of life [18–20]. Early Injection laryngoplasty has become a major treatment option for the acute-onset postoperative UVCP because of its effectiveness and low rate of complications [21]. In addition, early injection laryngoplasty for acute UVCP may reduce the need for eventual laryngeal framework surgery [21–23]. These studies support the theory that the early intervention by PIML brings paralysed vocal fold (VF) into a more favourable position and this can affect the final resting position of the VF even if meaningful movement does not return.

In our study, we have performed PIML early with the hope to provide the better quality of life and to avoid a delay in the planned treatment for their main diseases. Unilateral vocal cord palsy, if temporary, can take upto 6 months to recover and can be aided by PIML and speech therapy till recovery or compensation by other cord. If it is permanent, initially it has to be aided with speech or swallow therapy and Injection laryngoplasty till compensation by other cord. If no compensation achieved even after 6 months, then laryngeal framework surgery can be performed. In our study mean time of spontaneous recovery was 05 month with range from 4 to 6 months.

Various injectable materials for PIML have been used. Hyaluronic acid is propagated as an ideal injectable material, and it has since been widely used in clinical practice [24]. In our study we used hyaluronic acid in concentration of 23 mg/ml. The average maintenance period of hyaluronic acid is 9 to 12 months. It is tightly cross linked, excellent biocompatibility, and closely match to vocal cord bio viscosity [25, 26].

According to a meta-analysis MPT, GRBAS, and mean airflow rate were recognized as significant indicators of voice quality in patients with UVCP. The Jitter and the Shimmer, although very frequently reported and statistically valid in the literature come last in surgeon’s choice as voice outcome indicator for UVCP treatment assessment [27].

In the present study, multidimensional evaluation methods were used to evaluate voice and swallowing improvement after PIML which included- Perceptual evaluation by GBRAS, Subjective analysis by VHI 30, Aerodynamic analysis- MPT, Acoustic analysis and swallowing outcome analysis.

A study evaluated four main categories: quality of life questionnaires, perceptual evaluation grading system, voice laboratory recording, and image or video analysis and concluded that hyaluronic acid IL is an effective treatment for UVCP, which may achieve a long-term effect and therefore reduce the likelihood of requiring permanent medialisation thyroplasty [28].

A study aimed to investigate the effect of percutaneous injection laryngoplasty on voice and swallowing function in patients with cancer-related unilateral vocal cord paralysis and concluded Injection laryngoplasty significantly improved the glottal gap, vocal fold position, MPT, and VHI-10 and post-hoc analysis [29].

A systematic review by Pan S et al. reviewed evidence on effectiveness of injection laryngoplasty on aspiration outcomes in acute unilateral vocal fold paralysis. The results showed improvement in PAS scores after injection laryngoplasty [30].

In our study we achieved a significant decrease in VHI after Injection laryngoplasty (86.5 to 54.45 immediate post procedure) which further decreased to 46.71 by the end of 3 months and the effect maintained till 6 months. MPT increased significantly from 6.8 to 14.0 s immediately after PIML which further increased to 16 s at 3 month and significant effect maintained till 6 months. On perceptual evaluation- GBRAS, there is significant improvement after injection laryngoplasty and effect maintained till 6 months. On acoustic evaluation there was significant decrease in Jitter and shimmer and significant increase in HNR after injection laryngoplasty. There was no significant effect noted on effect of injection laryngoplasty on fundamental frequency. There was significant improvement in swallowing outcome after Injection laryngoplasty which was measured using PAS and the effect maintained till 6 months.

Our study has few limitations. Small sample size was enrolled in the study. There was no control group to compare only PIML versus PIML with voice & swallowing therapy or only voice & swallowing therapy without PIML. 15% mortality during study period due to primary disease and long-term effect in this subgroup could not be assessed. PAS used to evaluate swallowing only reflects the presence or absence of aspiration, not the quantity of aspiration. PIML was able to reduce the glottal gap, thereby decreasing aspiration, however, PAS cannot indicate a reduction in the risk of aspiration due to a decrease in aspiration volume. There were variances in the approach of PIML along with delay in procedure from onset of symptoms, we did not asses these parameters and their effect on final outcome. Further research on patients of UVCP with hoarseness with/without aspiration undergoing early PIML might confirm its efficacy on voice and swallowing outcomes.

Conclusion

We observed a significant improvement in the voice and swallowing outcomes after the PIML. The improvement sustained till the end of 6 months follow up. Definitive surgery could be avoided in almost 88% (4/34) of the cases after PIML. Early injection laryngoplasty is a safe and effective procedure in patients with UVCP with evidence of significant long-lasting improvement in voice and swallowing.

Funding

No funding sources.

Declarations

Ethical Approval

Taken.

Consent to Participate

Written informed consent was taken from individual patients included in the study.

Conflict of interest

The authors declare that they have no conflict of interests. Research involves human participants.