The upper esophageal sphincter (UES) is an important anatomical factor associated with dysphagia during swallowing. The UES is anatomically composed of the cricopharyngeal muscle, inferior pharyngeal constrictor muscle, and proximal part of the cervical esophagus. Among them, the cricopharyngeal muscle, which is the most important muscle related to cricopharyngeal dysfunction (CPD), exists between the lower pharynx and upper esophagus and plays an important role in opening and closing the esophagus through reflexive contraction and relaxation movements. CPD refers to incoordination and impairment of relaxation and con-traction of the UES. CPD has various causes, including central nervous system disorders, neuromuscular dis-orders, and trauma. CPD can be identified clinically using a video-fluoroscopic swallowing study (VFSS). If CPD causes excessive tension in the UES, post-swa-llow pharyngeal remnant and airway aspiration as well as dysphagia, malnutrition, dehydration and weight loss can occur. Therefore, it is important to treat CPD. Various methods are available for treating CPD, in-cluding balloon dilatation.

In this case, the effect of balloon dilatation was iden-tified using VFSS in a patient with CPD, and the treat-ment protocol was taught to the patient. The patient was able to continue the treatment on her own, even after discharge. Since then, continuous improvement has been observed in the VFSS results tracked in outpa-tient clinics.

A 41-year-old female patient visited the emergency room complaining of right hemiplegia and left facial dysesthesia that had begun 2 hour prior. The patient had no previous history of hypertension and diabetes. In addition, there were no underlying diseases that could cause swallowing disorders, such as previous strokes or other neurodegenerative diseases. Diffusion-weighted brain magnetic resonance imaging revealed a high-intensity signal from the left medulla.(Fig. 1) Posterolateral involvement with vertical extension of the left lateral medulla was observed. The patient was diagnosed with cerebral infarction. After acute treat-ment, cognitive, language, and motor function were relatively good compared to her status before the stroke; however, since the onset, the patient had a swallowing disorder and required a nasogastric tube. The patient was transferred to the Department of Rehabilitation Medicine for intensive rehabilitation. At the time of transfer, the patient had no abnor-malities in vital signs or blood test results. On neuro-logic examination, consciousness was clear, and the Korean Mini-Mental State Examination score was 27 out of 30. The patient was evaluated for at least four levels of muscle strength in both the upper and lower extremities using the manual muscle strength test, which was scored by the Medical Research Council scale. The patient’s hand function was sufficient to button up her clothes on her own.

Figure 1. (A) Brain magnetic resonance imaging scan showing a distinct signal in the region of the left medulla, in a diffusion-weighted image. (B) Apparent diffusion coefficient map.

To evaluate accurate swallowing conditions, oral and pharyngeal phases were evaluated through video fluoroscopy. The diet used was classified into six stages by formulation (liquid, nectar thick, honey thick, pudding thick, snack). In the first VFSS of this case, no abnormal finding was observed in the oral phase, with normal oral and laryngeal passage time. Neither nasal regurge nor abnormal finding of tongue base movement, hyolaryngeal elevation, pharyngeal muscle serial contraction, and epiglottis movement was found in VFSS. But delayed swallowing reflex onset timing and impaired and delayed UES opening were obser-ved. More than 50% of residues were observed in the valleculae and pyriform sinus with significant aspiration in every formulation during swallowing. The tradi-tional swallowing treatment such as Vital Stim (Encom-pass Health, Birmingham, AL) and oromotor training were performed 5 times a week for two weeks, but there was no improvement in the follow-up VFSS. As the patient strongly refused to use nasogastric tube, we decided to physically expand the narrowed crico-pharyngeal muscle. Therefore, balloon dilatation was performed through VFSS.(Fig. 2)

Figure 2. Videofluoroscopic swallowing study image showing the moment when the balloon starts to move down after laryngeal elevation during swallowing.

A 16-Fr silicone 2-way indwelling urinary catheter (Fortune Medical Instrument, Taoyuan City, Taiwan) was used for repeated balloon dilatation. The catheter was inserted through the mouth under VFSS. We inserted a 19-cm deflated catheter at the cricopharyngeal muscle, which is located between the fourth and sixth cervical vertebrae. Then, 10 cm³ of contrast was inje-cted to maintain the inflated balloon at approxi-mately 20 mm for 15 s while observing the VFSS. We then stimulated the swallowing reflex by asking the patient to swallow her saliva. After swallowing, we deflated the balloon and positioned it back between the fourth and sixth cervical vertebrae. This proce-dure was performed three times per minute with a break of 10 s for a total of five cycles. If the balloon slid out because of tension in the UES, it was inflated after passing through the UES to relax the muscles¹.

Immediately after balloon dilatation, most of the indicators observed in VFSS showed improvement, espe-cially residue in the valleculae and pyriform sinus for every diet formulation. In addition, the amount of aspiration was reduced in all diet formulations; for snacks and pudding in particular, no aspiration was observed. We judged that balloon dilatation was effec-tive and thought that it would be meaningful to conti-nue treatment. But we could not determine how long the treatment last. Therefore, we decided to find the best frequency for optimal effects in the absence of side effects. Balloon dilatation was performed over a three-week period, with the following frequency: once a week during the first week, once a day during the second week, and twice a day during the third week. VFSS follow-ups were conducted on the last day of each week.(Table 1)

Table 1 . Parameters of videofluoroscopic swallowing study.

Frequency	FOIS	PAS						Residue in vallcula/pyriform sinus					Pharyngeal wall coating	VDS	Recommended diet after VFSS
		Liquid	Nectar thick	Honey thick	Pudding thick	Snack		Liquid	Nectar thick	Honey thick	Pudding thick	Snack
Baseline	1	8	8	8	8	8		+++/+++	+++/+++	+++/+++	+++/+++	+++/+++	O	55.5	NG tube
Right after balloon dilatation	2	7	7	6	3	3		+/++	++/++	++/++	++/++	++/++	O	53.5	NG tube
Once a week for a week	2	7	7	6	3	2		+/+	++/++	++/+	++/++	++/++	O	51	NG tube
Once a day for a week	4	5	5	3	2	2		+/+	+/+	++/++	+/++	++/++	O	32	D1
Twice a day for a week	4	5	4	3	2	2		+/−	+/−	++/+	+/++	++/++	O	27.5	D2
Once a day with supervision for 3 days	5	3	3	3	2	2		+/−	+/+	+/+	+/++	++/+	X	21.5	D3
Once a day without supervision for 4 days	6	3	3	3	2	1		−/−	−/−	−/++	+/++	++/++	X	12.5	D4
Once a day for a week (outpatient clinic)	6	3	2	2	2	1		−/−	−/+	−/+	+/+	+/++	X	10.5	D4
Once a day for a month (outpatient clinic)	7	2	2	1	1	1		−/−	+/−	−/−	−/+	−/+	X	4.5	RD
Treatment termination for a 3 month (outpatient clinic)	7	2	2	1	1	1		−/−	−/−	−/−	−/−	−/+	X	4.5	RD

FOIS: functional oral intake scale, PAS: penetration aspiration scale, −: none, +: <10%, ++: 10%≤ <50%, +++: ≥50%, VDS: videofluoroscopic dysphagia scale, NG tube: nasogastric tube, D1: dysphagia diet level 1, D2: dysphagia diet level 2, D3: dysphagia diet level 3, D4: dysphagia diet level 4, RD: regular diet..

After balloon dilatation was performed at different frequencies, the optimal frequency was determined in consideration of the treatment effect and degree of discomfort. Not only did the amount of aspiration decrease, but the residues in the valleculae and pyri-form sinus also decreased continuously. In particular, the greatest improvement was observed when it was performed once daily. The Videofluoroscopic Dysphagia Scale (VDS) showed the most improvement from 51 points to 32 points, and the UES opening improved significantly in VFSS. After performing balloon dilata-tion once a day per week, there was no aspiration in pudding thick formulation and snack. Therefore, naso-gastric tube could be removed. The treatment also seemed effective when performed twice a day consi-dering the amount of residue in the valleculae and pyriform sinus, but the patient complained of slight discomfort such as nausea.

Next, the patient was trained to perform balloon dilatation on her own because she wanted to be dis-charged as soon as possible and wanted to perform this technique for herself at home. The patient used the same catheter that the medical staff used. The insertion length of the catheter was confirmed in pre-vious VFSS (19 cm), so we marked that point with a marker on the catheter. The patient then inserted the catheter herself for the set length. Next, water was injected to inflate the balloon and the same proce-dure was performed as before. As we decided earlier, balloon dilatation was performed once a day. For the first 3 days, the patient performed balloon dilatation under the supervision of a rehabilitation medicine doctor, and the side effects were assessed. After con-firming that there were no specific side effects, the patient performed balloon dilatation without supervision for the next 4 days.

The self-balloon dilatation was successful, and the patient did not complain of any side effects. Therefore, it was approved for self-treatment at home after dis-charge without monitoring, and the VFSS was follo-wed up in the outpatient clinic.

Since then, VFSS has been performed in the outpa-tient clinic on the first week and month after discharge. The patient’s dysphagia improved continuously. At the 1-month VFSS, test findings indicative of a regular diet were observed, and the balloon dilatation treat-ment was terminated. VFSS at 3 months post-treat-ment showed good results, as neither aspiration nor residue in the valleculae or pyriform sinus were found. In addition, the VDS score decreased from 55 to 4.5. This allowed the patient to remain on a regular diet.

CPD is an important cause of dysphagia, which can occur in 5-6% of patients with neurological disorders, including stroke². In particular, the prevalence of CPD is approximately 50% when there is a lesion in the brain stem³.

Various methods are used for CPD treatment. Crico-pharyngeal myotomy, which can be used as a treat-ment for CPD, has the advantage of being irrever-sible; however, various complications such as food reflux, infection, bleeding, perforation, and laryngeal nerve damage can occur owing to surgery⁴. Botulinum toxin injection treatment has a reversible effect dura-tion of 5-6 months, and complications may worsen dysphagia due to paralysis of the pharyngeal muscles or respiratory failure due to the spread of toxins⁵. In contrast, balloon dilatation can be performed relatively easily using VFSS and has been used because it is less invasive than cricopharyngeal myotomy or botulinum toxin injection; therefore, the risk of complications is low⁶.

The patient had severe dysphagia immediately prior to the onset of lateral medullary infarction. Further-more, due to the posterolateral and vertical location of the cerebral infarction lesion, dysphagia was likely to be long-lasting⁷. At first VFSS there was no abno-rmality at tongue base movement, hyolaryngeal ele-vation, pharyngeal muscle serial contraction and epi-glottis movement. But swallowing reflex onset timing and UES opening was delayed with impaired UES opening. Considering the results, the cause of dysphagia was thought to be CPD. As the patient had almost no problem with activities of daily living other than dys-phagia, she did not want to take nasogastric tube and receive long-term inpatient treatment. Therefore, among these treatments, we decided to try balloon dilatation. More aggressive treatment was no further needed since balloon dilatation was effective and the dysphagia was gradually improved as the treatment continued.

Balloon dilatation has not yet been standardized. The diameter, pressure, and extension time of the balloon depend on the operator’s personal experience and differ between studies. Several studies have intro-duced a balloon dilatation protocol by maintaining the balloon once for 15 s at a low pressure of appro-ximately 1-2 atm or inducing swallowing reflexes up to six times per minute for a total of 3 min. These methods were performed by inserting a 16-Fr catheter into the UES based on the 4-6th cervical vertebrae^8,9.

In this case, the protocol was set up by referring to a study that showed effective results by repeatedly attempting balloon dilatation¹⁰. Various treatment fre-quencies are applied depending on the patient’s degree of dysphagia, so it was agreed with the patient to find the optimal frequency of effect without discomfort during hospitalization. After confirming the effective-ness of the continuous treatment, the patient hoped to continue the treatment on her own after discharge.

As balloon dilatation was performed, continuous improvement in CPD was observed. The VDS score before balloon dilatation was 55 points, and it decreased to 4.5 points at the end of treatment. Not only did the amount of aspiration decrease, but the residues in the valleculae and pyriform sinus also decreased. In particular, the greatest improvement was observed when it was performed once daily. It was also effec-tive when performed twice a day, but the patient complained of slight discomfort such as nausea. After discharge, there was continuous improvement of swal-lowing in the follow-up VFSS and no side effects were observed even after self-treatment at home. As a result, the patient could eat a regular diet and the patient’s satisfaction with the treatment results was very high.

There are some studies that reported on the effect of balloon dilatation on dysphagia in patients with lateral medullary infarction^11,12, and a case report de-monstrated that early induction of balloon catheter dilatation achieved improvement of swallowing dys-function in lateral medullary infarction¹³. In this case, balloon dilatation was repeatedly performed at diffe-rent frequencies to determine the most efficient fre-quency, and the patient was educated about the pro-tocol so that the treatment could be performed inde-pendently.

However, this study has several limitations. First, it is difficult to ignore the effect of previous balloon dilatations as this is a single case study. Second, if a method to quantitatively evaluate the degree of CPD was used, such as manometry, the degree of improve-ment in swallowing disorders could have been evaluated more accurately. Third, it cannot be ruled out that traditional swallowing therapy or natural recovery may have had an influence. However, after discharge, no other swallowing treatment apart from balloon dil-atation was administered, yet a sustained improvement was observed. Therefore, it is presumed that the impact of traditional swallowing treatment was not significant. Furthermore, the patient had postero-lateral involvement with vertical extension of the left medulla infarction, which generally leads to severe dysphagia and slower recovery. However, in this case, rapid improvement was observed following the initi-ation of balloon dilatation therapy, suggesting that the effect of balloon dilatation had a more substantial influence than the natural course. In order to gene-ralize the effect of balloon dilation, further cases and research are necessary.

Despite these limitations, this case is valuable because the effect of balloon dilatation was confirmed when performed by the patient on her own and again after discharge. Furthermore, through various attempts, we found the individualized frequency of balloon dila-tation for the present patient. Due to this individua-lized treatment, the patient could progress from feeding through a tube to a regular diet. Therefore, If hand function and cognitive function are good in patients with severe dysphagia caused by CPD, self balloon dilation can be attempted.

No potential conflict of interest relevant to this article was reported.

This research did not receive any external funding or support.

This study was approved by the Dong-Eui Hospital Institutional Review Board (IRB No. DEMC-2022-04).

Woosup Song and Kihun Hwang: reviewed the topic and supervised all aspects of data collection, analysis, and report writing; Kyungmin Kim and Sanggyu Seo: conception and design. All authors contributed to data analysis and manuscript writing.