Surgical outcomes of cubital tunnel syndrome with acute symptom exacerbation caused by elbow ganglion cysts: a retrospective case series of 32 patients

Abstract

Background

Cubital tunnel syndrome (CuTS) caused by elbow ganglion cysts, characterized by abrupt onset or sudden exacerbation of ulnar nerve symptoms, is a rare condition with few reported cases. The current study aims to retrospectively assess the surgical treatment outcomes of patients with CuTS with acute symptom exacerbation caused by ganglion cysts from elbow joint.

Methods

From January 2023 to June 2024, patients diagnosed with CuTS with acute symptom exacerbation who were admitted to our hospital and followed up. Routine X-ray was performed to evaluate the degeneration of the elbow joint. Ultrasound test was used to evaluate the morphology of the ulnar nerve and ganglion cysts, especially in the elbow joint. Sensory deficit assessment of little finger according to British Medical Research Council Sensory Function Assessment Standards (BMRCS) and motor function assessment according to Medical Research Council (MRC) Scale for interosseous muscles strength were introduced. Surgical interventions including anterior subcutaneous transposition of the ulnar nerve and ganglion cyst resection were performed. Visual analogue scale (VAS) score was used to evaluate the pain of the patients. All the above parameters were collected and analyzed at the time points of pre-operation and final follow-up.

Results

A total of 32 patients was followed up with a mean age of 54.94 years, including 6 females and 26 males with 10 left and 22 right limbs affected. The period of follow-up ranges from 6 to 22 months (11.6 ± 5.4 months) post-operation. The X-ray indicated that 30 patients had osteoarthritis of the elbow joint. The symptom duration ranges from 0.5 to 24 months (6.0 ± 5.5 months). There were 4 cases of intraneural cysts and 28 cases of extraneural cysts according to ultrasound findings. In terms of sensory recovery, 18 cases (56.25%) achieved ≥ S3 + recovery, and of muscle strength recovery, 19 cases (59.375%) achieved ≥ M4 recovery post-operation. The parameters of sensory and muscle strength recovery above showed significant improvement (P = 0.0000038, and 0.0001318). The patients got significant pain relief after surgery according to the VAS scale with 16 cases (50%) experiencing complete disappearance of pain (P = 0.0000017).

Conclusions

For CuTS caused by elbow ganglion cysts presenting with abrupt onset or sudden exacerbation of symptoms, accurate diagnosis and surgical treatment was associated with improvement in pain and neurological parameters, though complete functional recovery is not guaranteed. In addition, distinguishing between intraneural and extraneural cysts may be informative for postoperative surveillance and individualized follow-up planning.

Introduction

Peripheral nerve injury (PNI) can result in significant sensory and motor deficits of the affected limb. Among the compressive neuropathies affecting the upper limbs, cubital tunnel syndrome (CuTS) is the second disease to carpal tunnel syndrome in prevalence. The reported annual incidence rates were 23.2 per 100,000 for men and 18.9 per 100,000 for women according to previous epidemiological data [1]. CuTS, characterized by the entrapment of the ulnar nerve within the cubital tunnel, presents a spectrum of clinical symptoms. Typical symptoms primarily involve sensory and motor deficits that significantly impair fine hand function, making it difficult to perform tasks such as pinching paper clips and other intricate hand manipulations. Diagnosis can be confirmed through ultrasound imaging, electrophysiological tests and other ancillary tests. Potential ulnar nerve entrapment sites around the elbow include five distinct locations: the arcade of Struthers, the medial intermuscular septum, the medial epicondyle, the cubital tunnel (the most common site), and the deep flexor-pronator aponeurosis [2, 3]. While these locations typically cause chronic compression of the ulnar nerve, little is known about cases presenting with abrupt onset or sudden exacerbation of ulnar nerve symptoms.

Compression of the ulnar nerve caused by elbow joint-related ganglion cysts usually occurs acutely, and most of the patients present with severe pain and acute atrophy of the target muscles in the hand, leading to early disabilities [4]. These symptoms are different from traditional chronic CuTS, which is characterized by numbness of the little and ring fingers without pain in the early stage. Ganglion cysts are benign mucinous tumors that typically arise near joints and can impinge on adjacent nerves due to their location and size [5]. The prevailing theory suggests that these cysts arise from nearby joints and are filled with synovial fluid [6]. During arthritis of the elbow joint, the high intra-articular pressure caused by joint effusions forces synovial fluid to migrate extra-articularly through the weakest points of the joint capsule. The entry point of the articular nerve branch is one such vulnerable site, which permits synovial fluid to accumulate beneath the neural sheath, extending both distally and proximally along the main nerve, eventually leading to the formation of ganglion cysts [7]. A thorough understanding of ulnar nerve anatomy and the common etiology of compression is required to determine the cause of neuropathy and guide appropriate treatment [8]. However, several factors may limit treatment outcomes in ganglion cyst-related CuTS with acute symptom exacerbation, including diagnostic delay, surgical urgency, and the potential for rapid neurological deterioration. Therefore, individualized treatment strategies are warranted.

In the current investigation, we reported the surgical treatment effect of elbow joint-related ganglion cysts induced CuTS with acute symptom exacerbation to share our own experiences.

Materials and methods

From January 2023 to June 2024, data from patients, who were diagnosed with CuTS, were retrospectively reviewed. The inclusion criteria were as follows: (i) adult patients aged 18–75 years; (ii) diagnosis of CuTS with acute symptom exacerbation based on abrupt onset or sudden exacerbation of pain in the ulnar nerve distribution; (iii) ultrasonography confirming the presence of elbow ganglion cysts and ulnar nerve compression. The exclusion criteria were as follows: (i) chronic CuTS without elbow ganglion cysts; (ii) other severe elbow pathology, such as fracture, dislocation, infection, or tumor; (iii) severe systemic diseases, including coagulation disorders, cardio-cerebrovascular diseases, systemic infections, or diabetic peripheral neuropathy; (iv) history of prior ulnar nerve injury or nerve repair; (v) inability to comply with preoperative evaluation, surgical treatment, or postoperative follow-up; (vi) prior conservative treatment for CuTS; (vii) recurrent symptoms after previous surgical intervention; (viii) other causes of ulnar neuropathy, such as cervical radiculopathy, thoracic outlet syndrome, or systemic neuropathies unrelated to ganglion cysts.

The diagnosis of CuTS with acute symptom exacerbation is based on clinical findings, including early onset of pain in the innervation territory of ulnar nerve, sensory deficit of the little finger, and reduction in muscle strength of the target muscles in hand. Ultrasound test was performed to evaluate the morphology of ulnar nerve and the existence of the ganglion cysts, and to detect the nerve compression relationship with cysts in the elbow joint. Intraneural ganglion cysts were identified by morphological features such as location within the nerve trunk or nerve fascicles, fusiform shape along the nerve long axis, residual nerve fascicular septa within internal anechoic area with separation and displacement of nerve fascicles, and synchronous movement with nerve on compression. Extraneural ganglion cysts are characterized by their location adjacent to the nerve sheath with round or oval shape without fascicular septa, but the nerve is externally compressed and displaced with an intact internal structure. As pain is the typical symptom of CuTS with acute symptom exacerbation, Visual Analogue Scale (VAS) score was used to evaluate the degree of the pain. Tinel Sign, Froment’s sign, Wartenberg sign and the existence of claw hand were also evaluated and recorded. Sensory deficit assessment of the little finger according to British Medical Research Council Sensory Function Assessment Standards (BMRCS) [9], and motor function assessment according to Medical Research Council (MRC) Scale for muscle strength [10] were introduced to assess the patient’s sensory and motor function at the time points of pre-operation and final follow-up. Motor function is assessed by evaluating the strength of the interosseous muscles [11]. Routine X-ray was performed to evaluate the degeneration of the elbow joint. Electrophysiological studies (EDS) are not mandatory for diagnosing CuTS associated with ganglion cysts, as false-negative results may occur in the acute stage before demyelination and axonal loss become detectable. Similarly, MRI is not essential when the cyst has been confirmed by other imaging (e.g., ultrasonography test). The diagnosis in the present case was established based on clinical presentation and imaging findings alone.

Surgical decompression with anterior subcutaneous transposition of the ulnar nerve was performed immediately after definitive diagnosis in the present cases. Ganglion cysts alongside the ulnar nerve in the elbow were confirmed during operation and were carefully explored and managed. Additional complete resection of the cysts and ligation of the cyst pedicles are necessary in cases of extraneural ganglion cysts procedures, and prompt incision and drainage of the cysts and ligation of the connected joint nerve branch are needed in cases of intraneural ganglion cysts. The surgical plan is formulated according to the patient’s condition, and all surgeries were performed following the same standardized procedure by a same surgical team.

Postoperatively, all the patients underwent a dressing change on postoperative day 2 with removal of the drainage tube, and a brace set at 90° of flexion was used at least for 3 weeks to immobilize the elbow joint. Patients were instructed to perform regular split-joint finger movements of the affected hand and shoulder abduction movements after operation under the assistance of a physical therapist. Postoperative ultrasound examinations were conducted to evaluate the recurrence of cysts.

Statistical analyses were performed using SPSS 27.0 for Windows. Data that were normally distributed are presented as the mean ± SD. For categorical data collected at the time points of pre-operation and final follow-up, including the Tinel sign, Froment’s sign, Wartenberg sign, and Claw hand, the McNemar test was initially applied. The Wilcoxon signed-rank test is appropriate for paired ordinal/nonparametric data, including the little finger sensation, interosseous muscle strength, and VAS scores. P values < 0.05 were considered statistically significant.

Results

A total of 32 patients were followed up with a mean age of 54.94 years and a mean body mass index (BMI) of 26.17. There were 6 females and 26 males with 10 left limbs and 22 right limbs affected. X-ray examinations indicated osteoarthritis of the elbow joint in 30 patients. The symptom duration ranged from 0.5 to 24 months (6.0 ± 5.5 months). Fifteen patients (46.9%) presented within 3 months due to severe pain of the affected extremity, the prolonged symptom duration in the remaining patients may be attributed to missed diagnosis during the process of seeking medical treatment or relieve of pain. The McGowan grade assessment of CuTS indicated 1 case of Grade I, 2 cases of Grade IIa, 4 cases of Grade IIb, and 25 cases of Grade III. All 32 patients were followed up for at least 6 months postoperatively. The patients’ baseline characteristics are shown in Table 1. Among the 32 patients, 15 (46.875%) cases presented with symptom duration of ≤ 3 months (short-duration group), while 17 cases (53.125%) presented with symptom duration of > 3 months (long-duration group). Patients in the long-duration group tended to present with more advanced neurological impairments, with a higher proportion of McGowan Grade III cases, reflecting delayed diagnosis or progressive deterioration prior to surgical intervention. In contrast, patients in the short-duration group were more likely to present with prominent pain and acute sensory-motor deficits, consistent with abrupt symptom onset or acute exacerbation. Baseline demographics and McGowan grading distribution of the two groups are summarized in Table 1.

Table 1.

Baseline of Patient Characteristics (n = 32)

Characteristics	Data
Mean age, years	54.94 ± 8.49
Genders
Female, n (%)	6 (18.75%)
Male, n (%)	26 (81.25%)
BMI	26.17 ± 3.13
Limb involved
Left, n (%)	10 (31.25%)
Right, n (%)	22 (68.75%)
Osteoarthritis of the elbow, n(%)	30 (93.75%)
Symptom duration, months	6.0 ± 5.5
Symptom duration, ≤3months	15(46.875%)
Symptom duration, >3months	17(53.125%)
McGowan grade
GradeI, n (%)	1, (3.125%)
GradeIIa, n (%)	2, (6.25%)
GradeIIb, n (%)	4, (12.5%)
GradeIII, n (%)	25, (78.125%)
Follow-up, m	11.6 ± 5.4

During operation, we confirmed that the majority of cystic lesions indeed arose from the medial aspect of the humeroulnar joint. The lesions were located adjacent to the ulnar nerve, causing direct external compression or intraneural involvement. The ganglion cyst stalk was clearly connected to the joint capsule, which verified the articular origin of these ganglion cysts. Combined with ultrasound findings, there were 4 cases with intraneural cysts and 28 cases with extraneural cysts, and two cysts were detected in the ulnar nerve of one case. The longitudinal length of the cysts ranges from 4 to 30 mm, including 7 cases less than 10 mm, 14 cases range from 10 to 20 mm, and 11 cases greater than 20 mm according to ultrasound data. The detailed characteristics of ganglion cysts are shown in Table 2.

Table 2.

Characteristics of ganglion cysts

Ganglion cysts	n (%)
Cyst type
Intraneural	4 (12.5%)
Extraneural	28 (87.5%)
Cyst number
One	31 (96.875%)
Two	1 (3.125%)
Cyst longitudinal length
<10 mm	7 (21.875%)
10–20 mm	14 (43.75%)
>20 mm	11 (34.375%)
Cyst recurrence
Yes	2(6.25%)
No, n (%)	30(93.75%)

Physical examination findings are shown in Table 3, with significant improvements observed in sensation of the little fingers and interosseous muscle strength compared with pre-operative data. In terms of sensory recovery, 18 cases (56.25%) achieved ≥ S3+, and of muscle strength recovery, 19 cases (59.375%) achieved ≥ M4 at the final follow-up. The sensation of the little finger and interosseous muscle strength showed significant improvement compared with preoperative data (P = 00001318). The Tinel sign disappeared in 21 cases according to follow-up results. The Froment’s sign and Wartenberg sign resolved in 16 and 20 cases post-operation, and the claw hand deformity were corrected in 20 cases (P = 0.0010908). Postoperatively, VAS scores significantly improved from 2.2 ± 1.1 to 0.6 ± 0.7 (mean difference: 1.6, P = 0.0000017), with 11 patients (34.4%) achieving complete pain relief. The detailed information is shown in Table 3. The reoccurrences of ganglion cysts were observed at 7- and 8-month follow-up respectively, with extraneural cysts identified by ultrasound test (Table 2). These two patients didn’t report the recurrence of the previous symptoms (pain, numbness or muscle atrophy) relating to ulnar nerve compression.

Table 3.

Physical examination findings and treatment outcomes

Parameters	Pre-operation (n)	Final Follow-up (n)	P value
Little finger sensation			0.0000038*
S2	30(93.75%)	4(12.50%)
S3	2(6.25%)	10(31.25%)
S3+	0	14(43.75%)
S4	0	4(12.50%)
Interosseous muscle strength			0.0001318*
M3	30(93.75%)	13(40.625%)
M4	1(3.125%)	18(56.25%)
M5	1(3.125%)	1(3.125%)
Tinel Sign			0.0000201&
Yes	26(81.25%)	5(15.625%)
No	6(18.75%)	27(84.375%)
Froment’s sign			0.0009674&
Yes	23(71.875%)	7(21.875%)
No	9(28.125%)	25(78.125%)
Wartenberg sign			0.0060396&
Yes	29(90.625%)	9(28.125%)
No	3(9.375%)	23(71.875%)
Claw hand			0.0010908&
Yes	28(87.5%)	8(25%)
No	4(12.5%)	24(75%)
VAS scale	2.2 ± 1.1	0.6 ± 0.7	0.0000017*

^* Wilcoxon test ^& McNemar test

Typical case is shown in Fig. 1.

Fig. 1.

Typical case of an intraneural cyst induced cubital tunnel syndrome. A 51-year-old male patient who admitted in our department with a chief complaint of numbness on the ulnar side of the right ring finger and little finger for 3 months. The VAS score was 6. The Wartenberg sign and Tinel sign were positive. At the final follow-up at 8 months post-operation, the sensation of the little finger got recovery from S2 to S4, and the strength of the interosseous muscles recovered from M3 to M4. The pain was significantly relieved. 1A Sensation deficits of the affected right hand (dotted). 1B The positive Froment sign of the right hand. 1C Obvious atrophy of the interosseous muscles (white arrow) and hypothenar eminence of the right hand is observed with a "claw hand" deformity. 1D Ultrasound test revealed an intraneural cyst with a length of approximately 15 mm along the ulnar nerve in the elbow. 1E Intraoperative observation of the intraneural cyst (white arrow). 1F Cyst fluid after drainage (black arrow)

Discussion

CuTS with acute symptom exacerbation caused by elbow ganglion cysts may differ from chronic CuTS in clinical features and disease course. Patients with this kind of CuTS often suffered by severe pain in the territory of ulnar nerve innervation at the early stage, followed by rapid atrophy of intrinsic hand muscles. Ultrasonography is a useful tool for identifying ganglion cysts and their relationship with the ulnar nerve. Prompt surgical treatment after definitive diagnosis, including decompression with anterior subcutaneous transposition of the ulnar nerve, cyst resection, and ligation of the cyst pedicles, may contribute to functional improvement of the affected hand, though outcomes are not uniformly favorable and depend on the severity of preoperative nerve damage.

Ganglion cysts around the nerves are relatively uncommon lesions that usually develop around the peroneal nerve, with the ulnar nerve being the second most common location [12, 13]. The clinical incidence of CuTS caused by ganglion cysts was reported to be 9% in previous reports [14]. According to the articular synovial theory, joint branches act as conduits for the propagation of cystic fluid to the parent nerve, and neighboring joints are irritants for the formation of cysts. There is a close correlation between the development of cysts and degeneration of the joints [15]. It is reported that CuTS caused by elbow joint–related ganglion cysts are usually associated with osteoarthritis of the elbow joint [16]. In the current investigation, the X-ray results of 30 in 32 cases (93.75%) indicated osteoarthritis of the affected elbow joints, which strongly suggests the possible relationship with the above-mentioned articular synovial theory. Since these abnormal elbows are associated with increased intra-articular pressure and synovial fluid production, which contributes to the formation of ganglion cysts. The ganglion cysts can be classified as intraneural or extraneural cysts. While, intraneural cysts were less reported than extraneural ones [17]. In the past decades, only 67 cases of intraneural ganglion cysts involving the ulnar nerve have been reported [15, 18–20]. Here, we reported 4 cases (12.5%) with intraneural cysts that induced CuTS. Both of the two types of cysts can cause severe compression of the ulnar nerves at the elbow joints.

Prompt treatment is needed after identifying the etiology of CuTS. In cases of CuTS induced by ganglion cysts, controversy still remains on complete removal of the cyst, on considering that these cysts have the potential for spontaneous resolution [6]. Previously, Tong et al. [21] reported 59 cases of CuTS caused by ganglion cysts, and 57 cases got excellent results undergoing procedures including subcutaneous transposition of the nerve following drainage of the cysts and ligation of the connecting articular branch. Weyns F. et al. [22] proposed a treatment plan for peripheral nerve compression caused by periarticular cysts, which included ligation of the joint branch and nerve decompression for intraneural cysts without complete excision of the cyst. For extraneural cysts, complete excision of the cyst was needed. In the present series, anterior subcutaneous transposition of the ulnar nerve was the preferred surgical approach in cases with concomitant osteoarthritis of the affected elbow joint. In case of extraneural cysts, additional complete resection of the cysts and ligation of the cyst pedicles were routinely performed. In cases of intraneural cysts, prompt incision and drainage of the cysts and ligation of the connected joint branches are needed. The above combined procedures can reduce the recurrence rate of CuTS induced by elbow joint–related cysts. Even though the recurrence rate of ganglion cysts was 13.6%, the recurrent cysts are no longer compressing against the already anteriorly placed ulnar nerve [21, 23]. It has also been suggested that failure in complete removal of the cyst stalk and membrane is a high-risk factor for recurrence [15, 24]. That’s why cysts recurred in two patients without relapse of the original compression syndromes of the ulnar nerves.

Elbow ganglion cyst–induced CuTS with acute symptom exacerbation has distinct clinical features compared with chronic CuTS. In terms of clinical symptoms, ganglion cysts induced CuTS are more sudden and severe. Except for similar sensation deficits of the fingers, patients often suffer from severe pain of the affected upper extremity, especially in the innervation territory of ulnar nerve [6, 25]. Following “claw hand” deformity can be observed due to rapid atrophy of interosseous muscles in a short term. In the current study, a total of 28 (87.5%) patients had claw hand deformities and 27 (84.375%) patients have experienced pain state during the admission. While, the above symptoms are always asymptomatic or mild in chronic CuTS patients at the early stage. We believe these early symptoms are beneficial for patients, as they prompt patients to seek medical attention as soon as possible. In the current study, there were 15 (46.875%) patients who visited the clinic within 3 months of symptom onset due to severe pain in the affected extremity. The prompt surgical treatment after a definitive diagnosis was associated with the function improvement of the ulnar nerve. In terms of diagnosis, patients with elbow osteoarthritis may be more susceptible to CuTS with acute symptom exacerbation due to ganglion cysts. Despite typical symptoms above, high frequency ultrasound test is recommended during the diagnosis process of these patients. The ultrasound can not only evaluate the compression degree of the nerve, but also can pinpoint the location and size of the cysts. The combination use of ultrasound has been identified as a favorable diagnostic tool in clinical practice [26, 27]. Magnetic resonance imaging (MRI) was also reported to clearly show the connection between the ganglion cyst and the joint [28], but we didn’t use it due to concerns regarding convenience and cost-effectiveness.

Another interesting phenomenon we found in this study is that the time of seeking medical attention was earlier in patients with intraneural cysts than in those with CuTS induced by extraneural cysts, with the shortest interval being 1 month after the onset of symptoms. The possible reason for this is that intraneural cysts grow in situ together with the nerve and, in a shorter period of time, lead to a direct increase in intraneural pressure of the nerve regardless of their size. While, symptoms of patients with extraneural cysts depend on the compressive relationship between the nerve and the cysts [5, 29]. If the cyst is close to the nerve and large enough to compress the nerve, it can cause acute or chronic compression and vice versa. Therefore, for patients presenting with early-onset pain and abnormal symptoms in the ulnar nerve innervation area within a relatively short period, CuTS caused by elbow joint–related ganglion cysts are highly suspected.

The current investigation also has some limitations. Firstly, the sample size of this study is relatively small, and randomized controlled trials with larger sample sizes are needed to confirm the findings of this investigation. Secondly, the mechanism of ganglion cyst formation in the arthritic elbow joints remains unclear. How to achieve the goal of early prevention and prompt detection of the disease is still a challenge for researchers and clinicians. Thirdly, the reason for the difference in population size of patients with intra- and extra-neural cysts is still unknown. Larger sample sizes and more attention are still needed in future studies to identify and distinguish the differences between them. Fourth, the retrospective design and absence of pre-symptom baseline data preclude differentiation between de novo acute neuropathy and acute exacerbation of chronic compression. Moreover, the wide symptom duration range (0.5–24 months; mean, 6.0 ± 5.5 months) and predominance of McGowan Grade III disease (78.125%) suggest that many patients likely had chronic ulnar nerve compression prior to presentation. Accordingly, " acute symptom exacerbation " in this manuscript denotes abrupt symptom onset or sudden exacerbation rather than a distinct disease entity. Prospective studies with longitudinal electrophysiological monitoring are warranted.

Another limitation of this study is the absence of validated patient-reported outcome measurements, such as DASH, QuickDASH, or Hand20. The current evaluation of functional recovery primarily relied on objective neurological parameters, which may not fully reflect patient-perceived disability and quality of life. Furthermore, grip strength and pinch strength were not assessed in this study. The inclusion of these objective functional measures would have provided a more comprehensive evaluation of motor recovery beyond the neurological grading systems used. Finally, although statistically significant improvements were observed postoperatively, statistical significance does not necessarily equate to clinically meaningful recovery. Given that the majority of patients presented with McGowan grade III disease and intrinsic hand muscle atrophy, functional recovery may be incomplete despite favorable P-values. Future studies should incorporate patient-reported outcome measures and functional assessments to better evaluate the clinical significance of surgical outcomes in this population. As this study also lacked a control group, we cannot determine whether surgical intervention is superior to conservative management, nor can outcomes be directly compared with chronic CuTS. Additionally, the observed improvements cannot be definitively attributed to surgery alone without controlling for spontaneous recovery. Therefore, our findings should be interpreted as descriptive outcomes, and future comparative studies are warranted.

In conclusion, CuTS with acute symptom exacerbation induced by elbow ganglion cysts typically presents with severe pain and neurological deficits in the ulnar nerve distribution. Once diagnosed, anterior subcutaneous transposition of the ulnar nerve was performed promptly in the present series, combined with appropriate management of the cysts according to their location (intraneural vs. extraneural). Ultrasonography is an effective tool for diagnosing CuTS with acute symptom exacerbation and identifying associated ganglion cysts.

Abbreviations

PNI

Peripheral nerve injury

CuTS

Cubital tunnel syndrome

VAS

Visual Analogue Scale

BMRC

British Medical Research Council

MRI

Magnetic resonance imaging

EDS

Electrophysiological studies

BMI

Body mass index

Authors’ contributions

H. Xian and R. Cong carried out the study design and performed the initial analysis of the data. XC. Guo contributed to literature review and original draft of the manuscript. H. Zhang conducted the surgical procedures and figure preparation. J. Wang and JK. Hao did the ultrasound tests and corresponding data collection. J. Ren and XC. Shi contributed to the follow-up process. All authors critically reviewed the manuscript and approved the final version of the manuscript for publication.

Funding

This work was supported by grants from the National Natural Science Foundation (NSFC) of China to to H. X. (82302681) and H. Z. (82302880).

Data availability

The original contributions presented in the study are included in the article, and further inquiries can be directed to the corresponding authors.

Declarations

Ethics approval and consent to participate

The current study was approved by the Ethics Committee of Xijing Hospital, the Air Force Medical University. This study was conducted in accordance with the Declaration of Helsinki, and written consent for participation and publication has been obtained from all the participants prior to enrollment.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.