Role of Electrodiagnostic Modalities in Detection of Nasal Septal Deviation

Abstract

Nasal Septal Deviation (NSD) is a common sign in otorhinolaryngology that can lead to facial asymmetry. In this case–control observational study, we assessed the role of EMG and NCS in the diagnosis of NSD and its effect on neuromuscular function. Participants were divided into two groups based on paranasal sinus computed tomography scan (PNS CT) results: NSD cases (n = 21) and controls without NSD (n = 13). EMG and NCS were performed on both groups to assess nasal alar muscles at the root of the zygomatic nerve. Our findings showed a significant correlation between NSD and EMG/NCS tests (P-value = 000) and a significant association between septal deviation and nasal alar lateralization (P-value = 000). EMG/NCS can be useful in assessing NSD by providing a better understanding of related neuromuscular structures and neuromuscular function of the nasal alar dilator muscles and aid in the diagnosis of NSD. Nasal Septal Deviation, EMG (electromyography), NCS (nerve conduction studies), Neuromuscular function, Facial asymmetry, Otorhinolaryngology, Paranasal sinus, Computed tomography, Nasal alar muscles, Zygomatic nerve, Nasal Obstruction, Nasal alar lateralization, Diagnosis.

Introduction

Nasal obstruction (NO) is a common complaint in otolaryngology and has significant financial implications [1]. NO may be caused by physiological or anatomical factors or both [2]. Anatomical causes, such as septal deformity, nasal valve dysfunction, and turbinate hypertrophy, contribute to NO [3, 4]. The prevalence of nasal septum deviation (NSD), a common cause of NO, is uncertain due to variations in classification systems [5]. NSD can arise from congenital deformities, polyps, cancers, infections, and birth-related traumas [6, 7]. NSD and nasal valve obstruction may result in snoring, nasal congestion symptoms, and aesthetic nose concerns [8, 9]. Precise assessment of NSD and its complications is necessary to develop an appropriate treatment plan. Imaging techniques have been used to evaluate NSD, but there is limited information on the effects of nasal deformities and facial asymmetries on electrodiagnostic modalities. Electromyography (EMG) and nerve conduction study (NCS) are tests that evaluate the electrical activity of muscles and nerves. Facial EMG is an objective and minimally invasive procedure to assess facial muscle activity, and it has been used to investigate emotions, fatigue, diseases involving facial muscles, and biomedical facial prosthetic devices [14, 15]. NCS is frequently performed with EMG to study neural injuries. Studies in animals suggest that NO can alter the activities of orofacial muscles [16, 17]. Therefore, we aim to evaluate the effectiveness of EMG/NCS in diagnosing NO and NSD.

Method

Patient Population

We enrolled 34 participants between the ages of 17–62 years who provided informed consent for this study. Patients with a history of alcohol or drug abuse that could affect EMG/NCS, neurological or systemic diseases, previous facial plastic surgeries, or other facial operations, and head traumas were excluded from the study. We assessed NSD based on the results of paranasal sinus computed tomography (PNS CT). Participants were divided into two groups: 21 patients with unilateral nasal obstruction symptoms and NSD in the study group and 13 individuals in the control group without NSD and nasal congestion complaint, such as polyps, masses, and valve obstructions. Both groups were referred to the neurology department to undergo electrodiagnostic tests: EMG and NCS.

EMG and NCS Procedure

The neurologist who conducted the tests was blinded to the outcome of PNS CT. The room temperature was maintained at 25 °C during the test. The patient's facial skin was cleaned with 70% alcohol and dried before the test. Patients sat comfortably upright throughout the experiment. The board-certified neurologist used the Dantec Keypoint EMG device (version 2.33) to perform EMG/NCS on the nasal branch of the facial nerve using the nasolabial fold and nasalis muscle to assess nasal alar muscles at the root of the zygomatic motor nerve. The neurologist performed percutaneous needling facial NCS and volitional needle EMG on each side of the nasal alae, stimulated the facial nerve at the point of stylomastoid (at the anterior of the styloid process), and captured compound muscle action potential (CMAP) of the transverse nasalis muscle by inserting a concentric needle ipsilaterally. During the test, patients were asked to deep breathe through their nostrils, and at rest, were studied to find motor unit action potential (MUAP). The analysis was made based on the recruitment and morphology of MUAP.

Statistical Analysis

We collected data from both groups after performing EMG/NCS and analyzed it using SPSS Statistics (Version 22). We presented the absolute data with mean ± SD or median with IQR. Mann–Whitney U test, independent sample t-test, or ANOVA test were used to reveal differences between groups, if applicable. A P-value less than 0.05 was considered statistically significant.

Results

Study Population

A total of 34 patients, including 15 females (44.1%) and 19 males (55.9%), participated in the study. The mean age of the patients was 38.32 ± 10.48 years with a median of 38 years and an age range of 17–62 years. The case group consisted of 21 patients (61.7%) with NSD based on PNS CT and nasal congestion symptoms, while the control group included 13 (38.2%) individuals without any sign or symptom of NSD and NO. Patients' characteristics are presented in Table 1. There were no significant differences between the two groups in terms of age, gender, and right and left airway diameter (P-values were 0.065, 0.675, 0.112, and 0.120, respectively). The entire dataset is presented in Table 2.

Table 1.

Demographic data and tests results

	Case group	Control group	Total
Female N (%)	10 (47.7%)	5 (38.5%)	15 (44.1%)
Mean age (years)	36.0 ± 9.9	42.0 ± 10.7	38.3 ± 10.5
Mean Lateralization (mm)	3.23 ± 1.39	1.15 ± 0.37	2.44 ± 1.39
Mean right nasal airway diameter (mm)	7.86 ± 4.96	10.75 ± 0.99	8.97 ± 4.16
Mean left nasal airway diameter (mm)	11.47 ± 4.85	10.84 ± 0.90	11.23 ± 3.82
Mean total airway diameter (mm)	19.340 ± 0.85	21.6 ± 1.67	20.20 ± 1.64
Mean right latency (ms)	2.93 ± 0.73	2.45 ± 0.47	2.75 ± 0.48
Mean left latency (ms)	3.30 ± 0.69	3.49 ± 1.06	3.37 ± 1.06
Mean right amplitude (mv)	5.14 ± 2.97	2.84 ± 1.04	5.14 ± 2.62
Mean left amplitude (mv)	5.07 ± 2.79	3.73 ± 1.75	4.56 ± 2.50

N number of participants; mm millimeter; ms milliseconds; mv Millivoltages

The mean lateralization refers to the deviation in millimeters of the nasal alar muscles from their normal position. The mean nasal airway diameter refers to the diameter of the right and left nasal airways. The mean total airway diameter refers to the sum of the right and left nasal airway diameters. The mean latency refers to the time between stimulation and response. The mean amplitude refers to the magnitude of the response

Table 2.

Results of electrodiagnostic modalities for detection of nasal obstruction

Case	Age	Gender	NSD			Alar Lateralization			Lateralization in (mm)	ANSD			RNAD (mm)	LNAD (mm)	TAD (mm)	Rght Latency (ms)	Left Latency (ms)	Right amplitude (mv)	Left amplitude (mv)
			R	N	L	R	N	L		R	NOT	L
1	37	F			■			■	4		■		13.84	5.31	19.15	3.37	2.52	5.40	1.67
2	39	M	■			■			5			■	4.33	14.45	18.78	3.08	3.52	.70	.90
3	49	M	■			■			4			■	4.64	14.87	19.51	2.54	3.56	4.70	2.50
4	25	M			■			■	5		■		15.39	4.34	19.73	3.04	3.08	5.70	5.60
5	29	M			■			■	4			■	16.54	3.80	20.34	3.42	3.52	1.88	3.70
6	41	M	■			■			5			■	4.63	15.20	19.83	3.04	3.26	2.20	1.50
7	38	F			■			■	3			■	13.24	5.47	18.71	2.90	2.95	10.00	6.70
8	22	F			■			■	4			■	14.70	5.33	20.03	3.42	2.91	10.90	7.50
9	32	F	■			■			3	■			3.26	16.32	19.58	3.50	5.22	3.50	3.20
10	19	M	■				■		2			■	5.13	14.23	19.36	1.69	2.74	5.10	7.50
11	37	F	■			■			4	■			4.34	14.24	18.58	3.75	3.02	8.10	8.50
12	38	M	■			■			3	■			3.20	14.37	17.57	3.60	3.56	4.10	5.00
13	34	M	■			■			3	■			3.83	16.28	20.12	1.42	1.90	3.26	3.33
14	54	M			■			■	2			■	13.84	5.37	19.21	2.91	3.06	4.80	8.80
15	17	M	■			■			3	■			5.12	14.25	19.37	2.87	2.87	4.73	4.73
16	36	F	■			■			1		■		5.42	12.45	17.87	3.38	3.50	8.40	9.10
17	36	F	■				■		2		■		3.93	14.24	18.17	3.50	3.38	9.10	8.40
18	46	F			■		■		1		■		14.73	4.63	19.36	1.00	4.63	2.83	3.38
19	53	F			■			■	4			■	4.60	15.20	19.80	2.65	2.83	.38	1.00
20	37	F	■			■			3	■			4.80	15.10	19.90	3.02	3.75	8.10	8.50
21	38	M	■				□		3		□		5.60	15.60	21.20	3.60	3.56	4.10	5.00
22	48	M		□			□		1		□		10.60	11.20	21.80	2.50	3.50	2.22	3.20
23	40	M		□			□		1		□		9.80	8.90	18.70	1.69	3.10	2.74	3.50
24	29	F		□			□		1		□		11.50	10.40	21.90	2.75	5.10	3.02	4.50
25	23	M		□			□		1		□		12.20	11.70	23.90	2.60	3.10	3.56	3.10
26	62	M		□			□		1		□		9.90	11.60	21.50	1.42	2.26	1.90	2.33
27	55	M		□			□		2		□		11.40	11.80	23.20	2.91	3.80	2.06	4.80
28	54	F		□			□		1		□		8.90	9.70	18.60	2.87	3.73	1.87	3.73
29	39	M		□			□		1		□		12.10	11.60	23.70	2.38	4.40	3.50	4.10
30	35	F		□			□		1		□		10.50	9.90	20.40	2.50	5.10	3.38	3.40
31	44	M		□			□		2		□		11.60	11.30	22.90	2.00	2.83	5.63	2.38
32	40	F		□			□		1		□		9.80	11.10	20.90	2.65	1.35	1.83	1.00
33	38	M		□			□		1		□		10.40	11.40	21.80	3.02	4.10	2.75	8.50
34	39	F		□			□		1		□		11.10	10.40	21.50	2.60	3.10	2.56	4.00

The checkmark (■) indicates the presence of a particular condition case study group ■ and control group □

NSD Nasal Septal deviation; L(mm) Lateralization in millimeter; ANSD Anterior Nasal Spine Deviation; RNAD Right Nasal Airway Diameter; LNAD Left Nasal Airway Diameter; TAD Total Airway Diameter; ms milliseconds; mv millivoltages

Data Analysis and Interpretation

There were significant differences between the case and control groups in terms of NSD grading (based on deviation of the septum to the right or left side in millimeters), alar lateralization (based on the photography of base view in millimeters), and ANSD, as shown in Table 3. The analysis of alar lateralization (3.23 ± 1.39 mm vs. 1.15 ± 0.37 mm), right latency (2.93 ± 0.73 ms vs. 2.45 ± 0.47 ms), left latency (3.30 ± 0.69 ms vs. 3.49 ± 1.06 ms), right (5.14 ± 2.97mv vs. 2.84 ± 1.04mv), and left (5.07 ± 2.79mv vs. 3.73 ± 1.75mv) between the case and control groups showed statistical significance (Table 3). Gender was significantly associated with alar lateralization and NSD (P < 0.004 and P < 0.000, respectively). The independent sample T-test between variables showed that NSD was significant in 2-tailed tests (P < 0.00), and lateralization was significant (P < 0.00). According to the results of the ANOVA test, NSD was significantly correlated with right and left airway diameter (mm), alar lateralization, and lateralization in mm; however, it had no significant association with right and left latency and voltage. There was a significant difference between NSD groups combined and linearity (P < 0.00) but not in age and groups or gender and groups.

Table 3.

Significant statistical analyses for electrodiagnostic modalities in the detection of nasal obstruction

Variable	P-value
Nasal Septal Deviation (NSD)	0.000
NSD grading	0.000
Alar lateralization	0.000
Anterior Nasal Spine Deviation (ANSD)	0.01
Lateralization in (mm)	0.000
Right latency in (MS)	0.003
left latency in (MS)	0.042
Right in millivolts (Rmv)	N/A
Left in millivolts (Lmv)	N/A

N/A indicates that no statistical analysis was performed for Rmv and Lmv

Discussion

Introduction of new techniques and advancements in technology have enhanced the ability of clinicians to diagnose and evaluate nasal obstruction (NO) and its underlying complications. Although various methods, such as medical history, examination, anterior rhinoscopy, flexible fiber optic endoscopy, and PNS CT, are available to diagnose NO and its severity and causes, they may not provide comprehensive evaluation of NO and its impacts on related nerves and muscles [18].

There is growing evidence in the literature about the role of NO and NSD in facial asymmetries and its effects on facial skeletal and organ development [10–13]. An animal study showed that NO leads to destructive changes in bones, emphasizing the need for a procedure that can detect NO and its impact on facial neuromuscular functions [19]. Electromyography (EMG) and nerve conduction studies (NCS) are two diagnostic modalities that can assess neural and muscular disorders.

Several studies have evaluated the electrical activity of facial muscles in NO, both alone and in coordination with nasal muscles. EMG/NCS tests have the potential to identify pathologies related to NO and NSD that cannot be found by other methods. Our study found a significant correlation between NSD and EMG/NCS tests unilaterally or bilaterally. Additionally, there were associations between NSD, alar lateralization, and right and left airway diameters [20–28].

In conclusion, EMG/NCS can be considered as a complementary diagnostic modality to evaluate NO and its effects on neuromuscular functions. While this study suggests EMG-NCS as another modality to detect NO and NSD based on the lateralization of the alae, with PNS CT as the gold standard, more studies with a larger sample size are required to validate these findings. Ultimately, better understanding of underlying complications of NO can lead to improvements in therapeutic strategies.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

All data generated or analyzed during the study is included in this article.

Declarations

Conflict of interest

There is no competing interest to declare.

Ethical Approval

Patients were enrolled in the study with informed consent. The study was approved by X University Internal Review Boards with Project no. of 8984.