Orthodontic treatment and musculoskeletal balance: a cross-sectional study of postural and functional outcomes in young adults

Abstract

Background

Orthodontic treatment is commonly employed to address various functional and aesthetic concerns, including potential abnormalities in the line of force. However, the correlation between the physical alterations resulting from orthodontic treatment and the associated potential risks has not been clearly established. This study aims to evaluate whether orthodontic treatment effectively enhances body balance in young individuals.

Methods

This cross-sectional cohort study involved right-handed, non-obese individuals aged 18 to 24 years. Eligibility criteria for the orthodontic treatment (OT) group included the completion of active orthodontic therapy within the last 6 months, with the entire treatment period not surpassing 2 years and those who had never undergone orthodontic treatment (NOT group). We assessed and compared their mastication rates, Axial Trunk Rotation (ATR) angles, left-right balance in muscle thickness and grayscale values of key muscles, and plantar pressure distribution.

Results

The OT group (n = 17) demonstrated a significantly lower mastication rate compared to the NOT group (n = 34), along with notable left-right imbalances in muscle thickness, particularly in the sternohyoid and rectus abdominis muscles. Although no significant left-right differences were observed in overall plantar pressure characteristics between the groups, ATR and mastication rate in the OT group showed significant correlations with specific muscle and plantar pressure characteristics.

Conclusion

Orthodontic treatment effectively achieves dental alignment, but our findings suggest it may also be associated with reduced mastication efficiency and indicators of bodily imbalance. Further studies are needed to confirm these associations.

Introduction

Individuals pursue orthodontic treatment for various reasons, including aesthetic concerns related to dental and facial appearance, oral health, and the correction of malocclusions [1]. With the growing influence of social psychology, many individuals seek to address cosmetic issues, such as smile aesthetics, through orthodontic interventions [2]. However, orthodontic treatment is not devoid of potential adverse effects, which may include muscle atrophy leading to a condition colloquially referred to as “orthodontic face,” as well as challenges related to the stability and longevity of tooth positioning, potentially affecting overall facial aesthetics [3]. While the necessity for orthodontic treatment is primarily determined by dental professionals, further research is warranted to evaluate the functional impacts for individuals whose concerns are predominantly aesthetic.

Firstly, existing research indicates that individuals in need of orthodontic treatment often demonstrate impaired masticatory function due to dental malalignment [4]. This compromised masticatory function which may lead to mandibular dysfunction, as studies have identified a correlation between neck muscle pain, including in the sternocleidomastoid, and imbalances in masticatory muscle activity. Additionally, activation points of the superior oblique muscle have been associated with temporomandibular disorders [5]. Moreover, individuals with mandibular dysfunction frequently exhibit issues related to foot pressure [6], and foot pressure parameters may serve as indicators of overall body balance. This evidence suggests that individuals requiring orthodontic treatment might experience mandibular problems and consequent musculoskeletal imbalances. Therefore, it is imperative to investigate whether participants undergoing orthodontic treatment experience improvements in these areas.

In our previous studies, we concentrated on the disparities in muscle quality and quantity associated with various chronic diseases, with a particular emphasis on the bilateral symmetry of limbs and their own musculature balance [7, 8]. While balance involves both static and dynamic elements and is affected by neuromuscular coordination and flexibility, overall muscular symmetry—across the left-right and upper-lower segments of the body—plays a crucial role in supporting optimal core stability and global stability [9, 10]. The objective of this research is to ascertain whether individuals who undergo orthodontic treatment experience enhanced mandibular muscle equilibrium and improved harmony within the helical chain, further affecting the trunk and extending to foot pressure balance, facilitated by the realignment of the orthodontic treatment.

Consequently, we hypothesized that orthodontic treatment would improve mastication rate, reduce muscular asymmetry, and promote more even plantar pressure distribution. This study aimed to test these assumptions.

Methods

Study design

This research constitutes a cross-sectional observational study, functioning as an ancillary investigation within a larger research project centered on the biomechanics of the lower limb force line. Data collection was conducted from March to June 2025. Before enrollment, all participants were thoroughly informed about the study’s objectives and procedures, and they provided written informed consent. The study was conducted in accordance with the ethical principles set forth in the Declaration of Helsinki.

Sample size

A formal sample size calculation was not conducted due to the exploratory nature of this study. However, based on existing literature in the fields of orthodontics and posture, we aimed to recruit 35 participants per group [11, 12].

Participations

Inclusion criteria include: (1) In light of the established correlation between muscle quality, quantity, and age [13], we confined the participant age range to 18–24 years; (2) all participants be right-handed; 3)body mass index of less than 24. Participants were categorized into two distinct cohorts: the Non-Orthodontic Treatment History group (NOT group), which included individuals with no history of orthodontic treatment, and the Orthodontic Treatment History group (OT group), comprising individuals who had recently concluded orthodontic treatment. A screening process was implemented to exclude participants with conditions such as flat feet, which could potentially influence foot pressure outcomes. For inclusion in the OT group, participants were required to have completed their orthodontic treatment within the two years and had been completed between one and six months before enrollment. Furthermore, OT group participants were mandated to provide pre-orthodontic photographs. This measure was implemented to subjectively screen and exclude individuals who may have undergone treatment for severe facial anomalies subjectively screened.

Chewing rate

Participants were instructed to thoroughly rinse their mouths to ensure oral cleanliness. Subsequently, they were provided with 4 g of roasted peanuts to chew for a duration of 20 s, with explicit instructions to refrain from swallowing. Upon completion of the chewing process, the participants spat out the peanut particles into a 2 mm sieve. They were then instructed to rinse their mouths again to ensure that any remaining food residue was also expelled into the sieve. The residue that did not pass through the sieve was collected on a porcelain dish, dried in an oven, and weighed. This dry residue weight was designated as the residual amount. The chewing rate was calculated using the following formula: Chewing rate = [(4 g - residual amount)/4 g] * 100 [14].

ATR

A scoliometer was employed to evaluate the Axial Trunk Rotation (ATR) angles of the participants. Measurements were taken at the cervical, thoracic, and lumbar regions of the spine. The angle demonstrating the highest ATR value was identified and documented as the participant’s ATR angle.

Measurement of muscle quality and quantity

Muscle thickness measurements, excluding those of the rectus abdominis and gluteus maximus, were performed with participants in a standing position while ensuring muscle relaxation. A 6–15 MHz linear-array transducer utilizing B-mode ultrasonography (Sonimage HIS; Konica Minolta, Tokyo, Japan) was employed for these assessments. The upper and lower trapezius muscles were measured following the methodology outlined by O’Sullivan et al. [15], which has been validated for reliability and reproducibility. The platysma was measured at the midpoint between the mandibular line and the clavicle, with the transducer aligned parallel to the clavicle. Particular attention was given to minimizing any head movement by the participant during the measurement process, due to the thinness of the platysma. The sternocleidomastoid muscle was assessed at the midpoint between the sternal manubrium and the mastoid process, with the ultrasound transducer oriented perpendicularly to the clavicle. The sternohyoid muscle was identified and evaluated by positioning the transducer adjacent to the clavicle and lateral to the thyroid cartilage. For the assessment of the rectus abdominis muscle, participants were positioned in a supine posture with a pillow placed beneath the knees. The transducer was aligned parallel to the superior border of the pubic symphysis, positioned 3 cm superior to the umbilicus and 3 cm lateral to the midline. Measurements were conducted at the end of expiration. For the evaluation of the gluteus maximus muscle, participants were positioned prone. The transducer was employed to locate the gluteus maximus superior to the ischial tuberosity at the level of the gluteal fold. Grayscale measurements were performed in accordance with our previously established methodology [7]. Specifically, ultrasound images were saved in JPEG format and analyzed using ImageJ software (https://imagej.nih.gov/ij/index.html; NIH, Bethesda, MD, USA) to determine the muscle grayscale value.

Foot press

A foot pressure analysis was performed to obtain the following static parameters using a pressure platform (WATMAT, Vismach Technology Ltd, China): weight-bearing line rate, axial load, forefoot load rate, hindfoot load rate, medial load rate, and lateral load rate. To minimize the influence of potential postural abnormalities, participants were instructed to execute a 360° turn in place prior to the commencement of measurements. Subsequently, they were required to maintain their stance with their eyes open for a period exceeding 10 s.

Statistical analysis

Before conducting the analysis, the data were evaluated for normality. Due to the non-normal distribution observed, the Mann–Whitney U test was utilized to compare general characteristics, such as age, gender, chewing rate, ATR, muscle thickness, and muscle grayscale, between the groups. For within-subject comparisons between the left and right sides, the Wilcoxon signed-rank test was applied. To assess the balance of muscle quality and quantity between the left and right sides of the body in the OT and NOT groups, delta values were computed as the difference between the right-side and left-side values. These delta values were not converted to absolute values, as imbalances could favor either side. Additionally, Spearman correlation analysis was conducted to explore the relationships between chewing rate, ATR, and various muscle- and foot pressure-related parameters in both groups.Data analysis was performed using SPSS 30.0 software (IBM SPSS, SPSS Inc., NY, USA) and GraphPad Prism 8.0 (San Diego, California, USA) was used for drawing pictures. Given the exploratory nature of the study, no corrections for multiple comparisons were applied. However, this increases the risk of Type I error, and findings should be interpreted with caution.

Results

Demographic and clinical characteristics

The study initially recruited 61 young participants, comprising 35 individuals without a history of orthodontic treatment and 26 individuals who had completed such treatment. The recruitment process was hindered by stringent eligibility criteria, which included specific requirements regarding age, the time elapsed since the completion of orthodontic treatment, and the total duration of the treatment. Consequently, while we successfully completed enrollment for the NOT group, many candidates screened for the OT group failed to meet the inclusion criteria. Through coordinated recruitment efforts across multiple dental hospitals, we ultimately enrolled 26 participants in the OT group. During the plantar pressure analysis, we detected abnormal measurements in a subset of these participants. Subsequent follow-up inquiries indicated that these anomalies were likely attributable to previous lower-limb injuries. Therefore, these participants were excluded from the final analysis. Specifically, one participant from the NOT group was excluded due to a history of recurrent temporomandibular dislocation. In the OT group, 2 participants with a history of metatarsal fractures, 3 with a history of knee pain, 2 with a history of ankle sprains, and 2 with planned future orthodontic treatment. Consequently, the analysis included 34 participants without prior orthodontic treatment and 17 participants who had completed orthodontic treatment within the preceding six months.

In comparing the general characteristics, a significant difference was observed in the chewing rate between the two groups. Participants who had undergone orthodontic treatment demonstrated a significantly lower chewing rate compared to those who had not (p < 0.01). Concerning muscle thickness, a significant disparity was found in the thickness of the left and right rectus abdominis muscles between the two groups (p < 0.01), with the OT group exhibiting a significantly thicker rectus abdominis muscle than the NOT group. Although the delta values of the muscles did not differ between the groups, the grayscale values of the sternohyoid and rectus abdominis muscles were significantly higher on the left side compared to the right side in the OT group, indicating a laterality that differed from the NOT group (Tables 1 and 2).

Table 1.

Demographic and muscle thickness

		Non-orthodontics treatment history	Orthodontics treatment history	P value
Age		20(18,21)	19(18,21)	0.119
Gender	Male	7	4	0.812
	Female	27	13
Chewing rate (%)		73.48(51.25,92.94)	63.71(37.55,99.05)	0.003*
ATR °		5(1,7)	4(1,7)	0.254
Muscle thickness
	L Upper trapezius	0.79(0.55,1.44)	0.77(0.5,1.1)	0.603
	R Upper trapezius	0.78(0.5,1.45)	0.69(0.19,1.12)	0.441
	L Platysma	0.48(0.27,1.01)	0.5(0.28,0.75)	0.704
	R Platysma	0.49(0.31,0.84)	0.42(0.32,0.79)	0.230
	L Sternocleidomastoid	1.06(0.63,1.96)	1.23(0.75,1.62)	0.238
	R Sternocleidomastoid	1.12(0.68,1.65)	1.21(0.59,1.55)	0.719
	L Sternohyoideus	0.65(0.44,0.96)	0.63(0.41,0.96)	0.478
	R Sternohyoideus	0.65(0.49,1.01)	0.59(0.45,1.07)	0.159
	L Lower trapezius	0.89(0.49,1.42)	0.85(0.42,1.64)	0.294
	R Lower trapezius	0.85(0.52,1.97)	0.86(0.45,1.25)	0.424
	L Rectus abdominis	1.72(0.79,2.69)	2.17(1.44,3.03)	0.007*
	R Rectus abdominis	1.67(0.8,2.85)	2.21(1.26,2.79)	0.005*
	L Gluteus maximus	4.6(3.18,6.12)	4.65(2.56,5.7)	0.966
	R Gluteus maximus	4.75(2.95,7.09)	4.57(3.16,6.74)	0.430

ATR, axial trunk rotation; L, left; R, right; △, delta value = right-left

Table 2.

Delta value of muscle thickness and grayscale

		Non-orthodontics treatment history	Orthodontics treatment history	P value
Muscle thickness (delta value)
	△ Upper trapezius	0(−0.25,0.22)	0.03(−0.58,0.2)	0.603
	△ Platysma	0.01(−0.33,0.33)	−0.01(−0.29,0.25)	0.542
	△ Sternocleidomastoid	−0.02(−0.5,0.56)	−0.03(−0.87,0.45)	0.555
	△ Sternohyoideus	0.03(−0.4,0.34)	0.01(−0.31,0.36)	0.719
	△ Lower trapezius	0.03(−0.45,1.04)	0.01(−0.41,0.3)	0.401
	△ Rectus abdominis	0.04(−0.41,0.48)	0.06(−0.44,0.5)	0.772
	△ Gluteus maximus	0.18(−1.82,3.52)	0.27(−1.39,2.63)	0.960
Muscle grayscale (delta value)
	△G Upper trapezius	0.95(−6.38,10.9)	−0.21(−11.43,9.86)	0.215
	△G Platysma	−0.2(−18.38,22.61)	−0.32(−6.41,15.87)	0.337
	△G Sternocleidomastoid	0(−31.95,30.27)	6.15(−6.59,20.87)	0.162
	△G Sternohyoideus	1.87(−13.66,17.17)	−4.23(−19.8,7.99)	0.003*
	△G Lower trapezius	0.13(−15.41,22.55)	−0.42(−11.56,9.29)	0.223
	△G Rectus abdominis	3.31(−13.63,31.5)	−2.27(−25.24,9.19)	0.001*
	△G Gluteus maximus	−4.8(−43.76,21.92)	−4.13(−45.15,23.73)	0.795

In the analysis of foot pressure data, neither group demonstrated significant left-right asymmetries, except for the axial load value in the NOT group, which was higher on the right side, although the p-value was 0.5. In the OT group, the distribution of axial load, similar to other foot pressure indicators, was relatively balanced between the left and right sides (Table 3). However, correlation analysis indicated that in the NOT group, the chewing rate exhibited a weak negative correlation with the delta value of the sternocleidomastoid (r=−0.378, p = 0.027) and a weak positive correlation with the right-side axial load (r = 0.340, p = 0.049). In contrast, in the OT group, the chewing rate showed a moderate negative correlation with the delta value of the sternocleidomastoid grayscale (r=−0.654, p = 0.004) and a moderate positive correlation with the right-side axial load (r = 0.515, p = 0.035). Furthermore, in the OT group, the degree of ATR was moderately positively correlated with the delta value of the sternohyoid muscle thickness (r = 0.570, p = 0.017), moderately negatively correlated with the left-side weight-bearing line rate (r=−0.520, p = 0.033), and strongly negatively correlated with the right-side weight-bearing line rate (r=−0.731, p = 0.001) (Fig. 1).

Table 3.

Foot pressure data between two groups

	Non-orthodontics treatment history		P value	Orthodontics treatment history		P value
	Left	Right		Left	Right
Weight-bearing line rate	70.75(15.1,90.7)	72.1(4.2,91.9)	0.668	68.4(16.3,91.4)	70.9(54,85.9)	0.356
Axial load	4.7(0,14.3)	6.75(0.3,14.9)	0.050	6(0.3,16)	6.8(0.6,20.9)	0.142
Forefoot load rate	55.5(43.7,78.1)	55.15(49.3,67.3)	0.694	53(45.1,63.9)	54.8(45.2,62)	0.320
Hindfoot load rate	44.5(21.9,56.3)	45(32.7,53.2)	0.407	45.3(36.1,50.3)	45.2(38,54.8)	0.507
Medial load rate	51.9(25.5,64.5)	53.95(26.1,61.7)	0.379	54.3(29,62.9)	53.9(14.2,62.7)	0.831
Lateral load rate	48.1(35.5,74.5)	46.05(38.3,73.9)	0.379	45.7(37.1,71)	46.1(37.3,85.8)	0.831

Fig. 1.

Correlation between chewing rate, ATR and muscle and foot pressure characteristics. (A). Non-orthodontics treatment history group; (B). Orthododontics treatment history group. ATR, axial trunk rotation; △, delta value = right – left; △G, delta value of grayscale; L, left; R, right.

In the investigation of the correlations between foot pressure and participants’ muscle characteristics, several statistically significant findings were observed. Within the NOT group, gait-related data demonstrated a correlation exclusively with the delta value of the upper trapezius muscle. Specifically, a weak positive correlation was identified with the right forefoot load rate (r² = 0.171, p < 0.05), alongside weak negative correlations with the right hindfoot load rate (r² = 0.129, p < 0.05) and the left axial load (r² = 0.188, p < 0.05). Conversely, in the OT group, the delta value of the sternohyoid muscle thickness exhibited a moderate negative correlation with the right weight-bearing line rate (r² = 0.233, p < 0.05). Additionally, a moderate negative correlation was observed between the right axial load and the delta value of the rectus abdominis muscle thickness (r² = 0.428, p < 0.05). Moreover, the left hindfoot load rate and the delta value of the upper trapezius muscle thickness demonstrated a moderate positive correlation (r² = 0.305, p < 0.05) (Fig. 2).

Fig. 2 Correlations between foot pressure and muscle characteristics.

(A). Delta value of upper trapezius in the Non-orthodontics treatment history group; (B). Delta value of Stemohyoideus in the Orthodontics treatment history group; (C). Delta value of upper trapezius in the Orthodontics treatment history group; (D). Delta value of rectus abdominis in the orthodomics treatment history group. △, delta value = right – left; L, left; R, right

Disscussion

In this study, we performed a cross-sectional analysis comparing mastication rate, ATR, left-right discrepancies in the quality and quantity of major muscles within the spiral chain, and foot pressure distribution between healthy young individuals with no history of orthodontic treatment and those who had completed orthodontic treatment within the preceding six months. Contrary to our initial hypotheses, individuals who had undergone orthodontic treatment demonstrated a reduced mastication rate and greater disruption in left-right body balance. Additionally, these balance indices were found to be correlated with the participants’ muscle quality or quantity.

Orthodontic interventions often enable patients to transition from chronic unilateral mastication to bilateral mastication [16]. However, our findings differ from much of the existing literature, which typically reports improvements in mastication after orthodontic treatment [17, 18]. Possible explanations include the potential decline in mastication rate due to long-term disuse, as the quality of mastication-related muscles, such as the masseter and temporalis, may deteriorate following extended orthodontic treatment. Consequently, the observed reduction in mastication rate among participants who underwent orthodontic treatment in our study appears plausible. Nonetheless, the mastication rate of these participants was comparable to the average mastication rate reported for healthy individuals by Sasa et al. [19], although it was significantly higher in participants who had not received orthodontic treatment. In contrast, the discomfort associated with orthodontic treatment may prompt individuals to chew and swallow food more quickly or choose softer food options, both of which can contribute to a reduced mastication rate, given that harder foods naturally require increased masticatory effort [4].

The sternohyoid muscle, responsible for facilitating the movement of the hyoid bone during mastication, has been previously documented to exhibit no significant differences between the chewing and non-chewing sides in healthy individuals [19]. Our findings corroborate this observation, as the delta value of the left and right sternohyoid muscles in participants without a history of orthodontic treatment was not statistically significant. Conversely, among participants who had received orthodontic treatment, the left-right disparity was highly significant, and this discrepancy was markedly distinct compared to those without orthodontic intervention, which was beyond the scope of our current explanatory framework.

In evaluating body power balance, our objective was to compare the quality and quantity of muscles within the spiral chain [20]. This chain comprises the bilateral neck muscles and upper trapezius as the upper section, the middle trapezius as the mid-crossing section, the abdominal region as the lower crossing section, and the gluteal region as the posterior crossing section. This comparison aimed to assess overall balance. Although foot pressure data did not indicate significant left-right differences among any participants, those who had received orthodontic treatment demonstrated correlations between the quality or quantity of various muscles and foot parameters associated with balance. Moreover, these foot parameters were significantly correlated with their axial trunk rotation (ATR), a relationship not observed in participants who had not received orthodontic treatment.

All participants in the study were right-handed, which led us to anticipate a dominance of the right side in most muscles, as noted in prior research [21]. However, among participants who had received orthodontic treatment, the grayscale values for the majority of muscles were notably higher on the left side. Based on our previous investigations and existing literature [7, 22] that suggest grayscale values are indicative of muscle strength, we hypothesize that these orthodontically treated participants may be experiencing a state of dysfunctional balance. Although they appear balanced in terms of foot pressure, they exhibit muscular imbalances across various regions. For example, participants might increase abdominal muscle contraction to enhance trunk stiffness, thereby improving body stability [23]. In our study, those who had undergone orthodontic treatment demonstrated significant left-right disparities in the grayscale values of the rectus abdominis muscle, which may indicate abnormal force generation during the maintenance of balance. This phenomenon may have been observable during the baseline inclusion process. To ensure that the inclusion criteria did not influence foot pressure outcomes, participants with knee and ankle issues were excluded. Although these issues were not prevalent among participants who had not undergone orthodontic treatment, a significant proportion of those who had received such treatment were excluded due to these conditions. Although we did not directly measure injury incidence, the observed imbalances could hypothetically increase susceptibility to lower limb injuries, a possibility warranting further investigation. Furthermore, in light of the current lack of recent systematic reviews or meta-analyses addressing the relationship between orthodontic treatment and postural effects, which could potentially validate the phenomena observed in our study’s findings, future research that explores the connection between dental treatments and musculoskeletal outcome measures would be regarded as innovative. Additionally, given the cross-sectional design, small sample size, and lack of baseline data, it is not possible to determine whether the observed imbalances pre-dated orthodontic treatment or were caused by it.

Limitation

Owing to the relatively limited sample size, it remains uncertain whether the functional abnormalities observed in these participants existed prior to orthodontic treatment or were induced or exacerbated by the treatment itself. Orthodontic interventions may not sufficiently address pre-existing functional issues [24]. Conversely, the orthodontically treated participants did not have pre-treatment data on masticatory rate, rendering it uncertain whether the observed reduction than NOT group is a consequence of orthodontic therapy or indicative of pre-existing deficiencies. Furthermore, participants were enrolled within six months following the completion of active orthodontic treatment to maintain the effects of the treatment. This early post-treatment period may have resulted in an underestimation of masticatory rate, as individuals may continue to adapt their chewing patterns beyond six months, potentially achieving improved performance. Future research should address these limitations by collecting baseline (pre-orthodontic) measurements and extending the follow-up period to capture long-term adaptations. Additionally, considering that orthodontic treatment decisions are frequently shaped by parental attitudes [1], future research should incorporate evaluations of lifestyle habits and other pertinent factors to enhance the understanding of their influence on these outcomes.

Conclusion

This finding is concerning, as it indicates that young individuals subjected to extended orthodontic treatment may develop physiological imbalances. Although dental alignment and symmetrical left-right plantar pressure may be achieved, the body’s spiral chain demonstrates atypical force generation to sustain this equilibrium. Further research is necessary to determine whether this abnormal balance pattern results in additional anomalies. Nonetheless, current evidence suggests that orthodontic treatment achieves dental alignment, but may also be associated with subtle musculoskeletal imbalances. These findings should be interpreted cautiously, and larger longitudinal studies are needed to clarify whether these changes are transient, adaptive, or clinically relevant.

Abbreviations

OT

Orthodontic treatment

ATR

Axial Trunk Rotation

Authors’ contributions

All authors have made substantial contributions to this work and have approved the final version of the manuscript. Concept and design: J.C.D., L.H.J.; Acquisition of data: J.C.D.,Q.E.W.; Statistical analysis: J.C.D., Y.Q.H.; Data interpretation: J.C.D., Y.Q.H., L.H.J.; Authorship of the original draft: J.C.D., Q.E.W.; Review and editing, L.H.J.

Funding

This study was funded by the Yunnan Rehabilitation Clinical Medical Center project (zx2019-04-02). This study was supported by the Second affiliated hospital of Kunming Medical University project (ynIIT2022007) and Education Department of Yunnan Province project (2024J0350).

Data availability

The datasets used and/or analyzed for the development of this manuscript are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Ethical approval for this study (PJ-2023-41) was obtained from the Second Affiliated Hospital of Kunming Medical University Internal Review Board. Prior to participation, written informed consent was obtained from patients or their families. The study was conducted in accordance with the ethical principles set forth in the Declaration of Helsinki.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.