Medical device, medical system, and method of operating a medical device

Abstract

[Problem] To provide: a medical device, a medical system, and a treatment method which impart stimulus to the vagus nerve that travels under an esophageal mucosa at an appropriate esophageal position, whereby it is possible to promote salivation while reducing the burden on a subject;. [Solution] This medical device 100 has: a stimulation part 110 which can impart a stimulus for promoting salivation to the vagus nerve traveling under a mucosa of an esophagus E; a support structure 120 in which the stimulus part is disposed; and a support part 130 which supports the support structure with respect to the esophagus, thereby holding the stimulus part between a second stricture N2 of the esophagus and a third stricture N3 of the esophagus in a position fixing manner.

Description

[Technical Field]

[0001] The present invention relates to medical devices, systems, and treatment methods used to stimulate saliva production in a subject. [Background technology]

[0002] Changes in body fluid volume in patients with heart failure and other conditions significantly impact the stress on organs such as the heart and kidneys. Therefore, actions that alter body fluid balance, such as drinking and urination, performed by patients in their daily lives have a significant impact on the pathology of heart failure. For example, during the acute phase of heart failure, doctors and nurses perform medical procedures such as intravenous fluid administration and diuretic administration, as well as urine output management, so that patients' body fluid balance is strictly controlled by medical professionals. However, strict control of patients' behavior in daily life is difficult. On the other hand, experiments using model animals have shown that restricting the amount of water consumed at one time reduces total water intake and preserves cardiac function compared to when the restriction is not imposed. Therefore, actions to increase body fluids in daily life, especially controlling water intake through drinking, are extremely important for heart failure patients.

[0003] However, when trying to control body fluid volume by restricting a patient's water intake, the patient experiences thirst, causing the body to require more fluid. Elderly patients are also prone to thirst if they are unable to drink enough water or produce enough saliva, and they may not even be aware that they are experiencing thirst. Therefore, controlling body fluid volume by restricting water intake is not easy.

[0004] One possible solution to the above problem is to control the amount of saliva produced by the patient. If it were possible to intentionally control the amount of saliva produced, it would be possible to prevent the patient from experiencing dry mouth. This would make it possible to maintain a constant body fluid volume while limiting the amount of water consumed.

[0005] It is known that one of the mechanisms by which saliva secretion is promoted is the activation of the vagus nerve (afferent vagus nerve) running under the mucosa of the esophagus, which causes reflex saliva secretion. Furthermore, Patent Documents 1 and 2 disclose medical devices for nerve stimulation that are configured to be placed inside the body of a subject. For example, it is believed that by placing the medical devices disclosed in Patent Documents 1 and 2 in the patient's esophagus and stimulating the vagus nerve running under the mucosa of the esophagus, it is possible to control the amount of saliva produced by the patient. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2018-175044 [Patent Document 2] Special table number 2003-530169 Summary of the Invention [Problem to be solved by the invention]

[0007] However, considering the anatomical location of the esophagus, there are some areas of the esophagus where it is not desirable to apply stimulation. The recurrent laryngeal nerve and the aortic arch are located around the first esophageal stenosis (upper esophageal stenosis). Therefore, applying stimulation to the first esophageal stenosis may cause unwanted reactions other than saliva secretion. Furthermore, the diaphragm and sphincter are located near the third esophageal stenosis (lower esophageal stenosis). Therefore, considering the effects on the patient's body, it is not desirable to actively apply stimulation to the area near the third esophageal stenosis.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device, medical system, and treatment method that can stimulate saliva secretion while reducing the burden on the subject by stimulating the vagus nerve, which runs under the mucosa of the esophagus, at an appropriate position in the esophagus. [Means for solving the problem]

[0009] A medical device that achieves the above-mentioned objective comprises a stimulation unit capable of applying stimulation to the vagus nerve running under the mucosa of the esophagus to promote saliva secretion, a support structure on which the stimulation unit is disposed, and a support unit that supports the support structure against the esophagus, thereby holding the stimulation unit in a fixed position between the second stenosis of the esophagus and the third stenosis of the esophagus. [Effects of the Invention]

[0010] According to the above medical device, the stimulation unit disposed on the support structure can be held fixedly between the second esophageal stricture and the third esophageal stricture. With the medical device placed in the esophagus, the stimulation unit stimulates the vagus nerve running under the esophageal mucosa, thereby promoting saliva secretion in the subject. Furthermore, by using the medical device, stimulation can be prevented from being applied to the areas surrounding the first esophageal stricture and the third esophageal stricture, thereby reducing the burden on the subject. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a simplified view of a medical device and a medical system according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a medical device according to a first embodiment. [Figure 3] 3A is a plan view of the medical device as seen from the direction of arrow 3A in FIG. 2. FIG. [Figure 4] 1 is a cross-sectional view (longitudinal cross-sectional view) of an esophagus, schematically illustrating an example of use of the medical device according to the first embodiment. [Figure 5] 1 is a flowchart showing a control flow of a medical system. [Figure 6] FIG. 10 is a cross-sectional view of the esophagus, schematically illustrating an example of use of a medical device according to Modification 1 of the first embodiment. [Figure 7] FIG. 10 is a cross-sectional view of the esophagus, schematically illustrating an example of use of a medical device according to Modification 2 of the first embodiment. [Figure 8] FIG. 10 is a plan view of a medical device according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view of the esophagus, schematically illustrating an example of use of the medical device according to the second embodiment. [Figure 10] FIG. 10 is a partial cross-sectional view (transverse cross-sectional view) of the esophagus for explaining an example of use of the medical device according to the second embodiment. [Figure 11] FIG. 10 is a plan view of a medical device according to a first modification of the second embodiment. [Figure 12] FIG. 10 is a plan view of a medical device according to Modification 2 of the second embodiment. [Figure 13] FIG. 10 is a cross-sectional view of the esophagus, schematically illustrating an example of use of a medical device according to Modification 2 of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0013] First Embodiment Fig. 1 is a diagram showing a simplified view of a medical system 10 and a medical device 100. Figs. 2 and 3 are diagrams showing the configuration of each part of the medical device 100. Fig. 4 is a diagram showing an example of use of the medical device 100, and is a cross-sectional view (longitudinal cross-sectional view) of the esophagus E of a subject in which the medical device 100 is placed. Fig. 5 is a diagram showing the control flow of the medical system 10.

[0014] 1 and 4 show schematic diagrams of parts of a subject's body. The symbol E indicates the subject's esophagus, the symbol O indicates the subject's oral cavity, and the symbol S indicates the subject's stomach. The symbol N1 indicates a first stenosis of the esophagus E (upper esophageal stenosis), the symbol N2 indicates a second stenosis of the esophagus E (middle esophageal stenosis), and the symbol N3 indicates a third stenosis of the esophagus E (lower esophageal stenosis). The symbol L indicates the lumen of the esophagus E, and the symbol Ew indicates the inner wall of the esophagus E.

[0015] In the description of the specification, the position of the oral cavity O side (also referred to as the "pharyngeal side") of the esophagus E is referred to as the "upstream position of the esophagus E," and the position of the stomach S side of the esophagus E is referred to as the "downstream position of the esophagus E." Furthermore, the extension direction of the esophagus E refers to the up-down direction of the esophagus E in Figures 1 and 4.

[0016] The medical system 10 and medical device 100 according to this embodiment are used to stimulate saliva secretion in a subject. The subject may be, for example, a heart failure patient for whom control of bodily fluid volume, including saliva volume, is desired. However, the medical system 10 and medical device 100 are not particularly limited in terms of the type of disease, pathology, symptoms, etc., as long as they are intended to stimulate saliva secretion in the subject.

[0017] (Medical device 100) A medical device 100 according to this embodiment will be outlined with reference to Figures 1, 2, 3, and 4. The medical device 100 includes a stimulation unit 110 capable of applying stimulation to the vagus nerve running under the mucosa of the esophagus E to promote saliva secretion, a support structure 120 on which the stimulation unit 110 is disposed, and a support unit 130 that supports the support structure 120 with respect to the esophagus E, thereby holding the stimulation unit 110 in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E.

[0018] The medical device 100 constitutes a medical system 10 together with a monitoring device 200 and a control unit 300, which will be described later.

[0019] 2 and 3, the support structure 120 has a tubular structure in which a lumen 125 is formed that extends in the longitudinal direction (left-right direction in FIG. 3) of the support structure 120. Note that arrow X in the figures indicates the longitudinal direction of the support structure 120, and arrow Y indicates the width direction of the support structure 120 that is perpendicular to the longitudinal direction.

[0020] The support structure 120 has a first opening 121a formed at one longitudinal end 121, a second opening 122a formed at the other longitudinal end 122, and an inner cavity 125 extending in the longitudinal direction.

[0021] The support structure 120 has an outer diameter that gradually decreases from both ends 121 and 122 toward the center in the longitudinal direction.

[0022] The first opening 121a and the second opening 122a communicate with the lumen 125. As shown in FIG. 4, the one end 121 where the first opening 121a is formed is located at a position upstream of the esophagus E relative to the other end 122 where the second opening 122a is formed. When the subject ingests food or the like with the medical device 100 placed in the esophagus E, the food or the like moves into the lumen 125 through the first opening 121a. After passing through the lumen 125, the food or the like moves toward the stomach S through the second opening 122a. Therefore, even with the medical device 100 placed in the esophagus E, the subject can prevent the movement of food or the like to the stomach S from being obstructed by the medical device 100.

[0023] Note that the lumen 125 does not have to extend continuously along the longitudinal direction of the support structure 120. For example, when the support structure 120 is made up of multiple members (e.g., a first portion 120A, a second portion 120B) as shown in an embodiment described later, a lumen can be formed in each member that makes up the support structure 120 (see, for example, FIG. 8).

[0024] 2 and 3, the stimulation unit 110 is disposed in an intermediate portion 123 located between one end portion 121 and the other end portion 122. The stimulation unit 110 is attached to the outer surface of the intermediate portion 123 of the support structure 120.

[0025] As shown in Fig. 4, the stimulation unit 110 is arranged so as to come into contact with the inner wall Ew of the esophagus E when the support structure 120 is supported in the esophagus E by the support unit 130. Moreover, as shown in Fig. 2, the stimulation unit 110 is arranged along the entire circumferential circumference of the support structure 120. By arranging the stimulation unit 110 in this manner, it becomes possible to apply stimulation over a wide range in the circumferential direction of the inner wall Ew of the esophagus E. Therefore, saliva secretion in the subject can be effectively stimulated.

[0026] There is no particular limitation on the position at which the stimulation unit 110 is arranged in the longitudinal direction of the support structure 120. For example, the stimulation unit 110 may be arranged in a position close to one end 121 or in a position close to the other end 122, or multiple stimulation units 110 may be arranged in different positions in the longitudinal direction of the support structure 120. There is also no particular limitation on the position at which the stimulation unit 110 is arranged in the circumferential direction of the support structure 120. For example, the stimulation unit 110 may be arranged in only a part of the circumferential direction of the support structure 120, or multiple stimulation units 110 may be arranged in different positions in the circumferential direction of the support structure 120.

[0027] The stimulation unit 110 has, for example, an electrode capable of applying electrical stimulation to the vagus nerve running under the mucosa of the esophagus E. The stimulation unit 110 can be made of, for example, a material capable of expanding the folds (see FIG. 10 ) present in the inner wall Ew of the esophagus E. The electrode can be disposed on at least a portion of the stimulation unit 110 so as to reliably contact the mucosa of the esophagus E when the medical device 100 is placed in the esophagus E. Alternatively, the entire stimulation unit 110 may be made of a conductive metal and disposed so that at least a portion of the stimulation unit 110 contacts the mucosa of the esophagus E. The stimulation unit 110 can be made of a material that can contract and / or expand when delivered to or retrieved from a target site (destination site). The material for the stimulation unit 110 can be, for example, a metal such as stainless steel, but is not limited to this. The start and stop of stimulation by the stimulation unit 110, the magnitude of the stimulation (the magnitude of the current value), and the like can be controlled by the control unit 300. The stimulation unit 110 can be configured as a self-discharging or self-storing type that receives control commands from the control unit 300 and generates electricity for stimulation, or as an external power supply type that receives electricity from an electricity supply unit located outside the body and applies electricity for stimulation.

[0028] The type and form of stimulation applied by stimulation unit 110 are not particularly limited as long as stimulation for promoting saliva secretion can be applied to the vagus nerve running under the mucosa of the esophagus E. Stimulation unit 110 can be configured as, for example, a unit configured to generate heat by a magnetic field, an electric field, or the like applied from outside the esophagus (for example, in the thoracic cavity or outside the body) and apply stimulation by heat, a unit configured to apply stimulation by ultrasound, a unit configured to place a stimulating drug applied to stimulation unit 110 on the mucosa of the esophagus E, a unit configured to generate and charge electricity using the peristaltic movement of the esophagus E or hydrogen ions present in the esophagus E and apply electrical stimulation or thermal stimulation, or a unit configured by arbitrarily combining the above-mentioned forms that apply the various types of stimulation exemplified above.

[0029] The support structure 120 according to this embodiment has a mesh structure that can deform to follow the movement of the esophagus E (e.g., peristaltic movement) while the support structure 120 is held within the esophagus E. The support structure 120 can be formed, for example, from a member such as a known esophageal stent that has a main skeleton made of braided metal wires or a main skeleton made of a tubular member with gaps formed therein. By being configured in this way, the support structure 120 can have high followability to deformation of the esophagus E in the radial direction, longitudinal direction (axial direction), and torsional direction.

[0030] The constituent material of the support structure 120 is not particularly limited. However, considering that the support structure 120 will be placed in the esophagus E, it is preferable to use a material that is highly acid-resistant, not corroded by gastric juice, and has high followability to the movement of the esophagus E described above. Such a material may be, for example, a superelastic alloy such as a nickel-titanium alloy. Furthermore, it is preferable that an appropriate surface treatment be performed to increase corrosion resistance.

[0031] Although a member having a mesh structure such as an esophageal stent has been exemplified as the support structure 120, the specific structure of the support structure 120 is not particularly limited as long as it can be placed in the esophagus E. Furthermore, even when the support structure 120 is configured with a mesh structure, there are no particular limitations on the density of the mesh or the mesh pattern. Furthermore, a cover may be placed on the inner surface of the support structure 120 to prevent food and the like from leaking from the lumen 125.

[0032] As shown in Figures 1 and 4, the support portion 130 has a first support portion 131 that abuts against the inner wall of the esophagus E at a position downstream of the second stenosis N2, and a second support portion 132 that abuts against the inner wall Ew of the esophagus E at a position downstream of the esophagus E from the position where the first support portion 131 is located and upstream of the esophagus E from the third stenosis N3.

[0033] 2, 3, and 4, in this embodiment, the first support portion 131 is configured at one end portion 121 of the support structure 120 in the longitudinal direction. The second support portion 132 is configured at the other end portion 122 of the support structure 120 in the longitudinal direction. In other words, each of the support portions 131 and 132 is configured as a part of the support structure 120.

[0034] 4, with the medical device 100 placed in the esophagus E, the first support portion 131 formed by one end 121 of the support structure 120 can be positioned so as to abut against the protruding portion of the inner wall Ew that forms the second stricture N2 in the lumen L of the esophagus E from a position on the downstream side of the esophagus E. In addition, the second support portion 132 formed by the other end 122 of the support structure 120 can be positioned so as to abut against the protruding portion of the inner wall Ew that forms the third stricture N3 in the lumen L of the esophagus E from a position on the upstream side of the esophagus E.

[0035] As described above, the support structure 120 is held in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E by maintaining a state in which the first support portion 131 abuts against the protruding portion of the inner wall Ew that forms the second stenosis N2 in the lumen L of the esophagus E and the second support portion 132 abuts against the protruding portion of the inner wall Ew that forms the third stenosis N3 in the lumen L of the esophagus E. Furthermore, the stimulation unit 110 disposed in the intermediate portion 123 of the support structure 120 is held in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E, similar to the support structure 120.

[0036] As shown in FIGS. 3 and 4, the support portion 130 has a tapered shape that widens in the radial direction away from the central axis C1 of the support structure 120. That is, one end portion 121 constituting the first support portion 131 has a shape that widens in diameter outward from the central axis C1. Furthermore, the other end portion 122 constituting the second support portion 132 has a shape that widens in diameter outward from the central axis C1. Therefore, as shown in FIG. 4, when the medical device 100 is placed in the esophagus E, each end portion 121, 122 abuts in a protruding state against the protruding portions of the inner wall Ew that form each of the strictures N2 and N3. This makes it possible to stably hold the medical device 100 at a desired position in the esophagus E.

[0037] The support parts 130 (first support part 131, second support part 132) do not have to be configured as part of the support structure 120. In other words, a member having the function of holding the support structure 120 at a desired position in the esophagus E may be attached to the support structure 120. There are also no particular restrictions on the shape, position, number, etc. of the support parts 130. For example, one of the first support part 131 and the second support part 132 may be configured in a shape as described in Modification 1 below (see FIG. 6).

[0038] Furthermore, in the medical device 100, visible and / or imageable markers M1 and M2 can be mounted on the support portions 131, 132, and 133 or the support structure 120 so that the positional relationship between the support portions 131 and 132 and the stenoses N2 and N3 can be clearly determined when the surgeon places the medical device 100. As an example, the markers M1 and M2 can be made of Au or Pt markers that are radiopaque and located in or near the first opening 121a and the second opening 122a. Similarly, to enable the surgeon to recognize the position of the stimulation portion 110, markers M3 and M4 that make each end recognizable can be mounted on the proximal and distal ends of the stimulation portion 110. Note that the material and shape of the markers M1, M2, M3, and M4 may be recognizable externally using imaging technology, and the markers M1, M2, M3, and M4 may be arranged circumferentially at regular intervals and continuously.

[0039] (Healthcare System 10) As shown in FIG. 1, the medical system 10 includes a medical device 100, a monitoring device 200, and a control unit 300.

[0040] The medical system 10 performs controls to control the volume of bodily fluids in a patient wearing the medical device 100.

[0041] As described above, in this embodiment, with the medical device 100 placed in the esophagus E, the stimulation unit 110 of the medical device 100 is activated to stimulate the vagus nerve running under the mucosa of the esophagus E, thereby promoting saliva secretion. When a treatment for promoting saliva secretion using the medical device 100 is performed, the subject wears the monitoring device 200. The control unit 300 controls the operation of the stimulation unit 110 based on the body fluid indicators acquired by the monitoring device 200. The control unit 300 controls, for example, the timing for starting and stopping the stimulation by the stimulation unit 110, the strength of the stimulation, etc.

[0042] 1, a device having a structure that can be attached to the oral cavity O of a subject can be used as the monitoring device 200. The monitoring device 200 can be configured, for example, as a patch-type structure that can be attached to the oral cavity O.

[0043] The body fluid indices acquired by the monitoring device 200 may include, for example, parameters related to the subject's saliva and parameters related to the amount of water in the blood. Examples of parameters related to saliva include the amount of saliva, the viscosity of saliva, the hydrogen ion exponent (pH value) of saliva, and the amount of protein in saliva. Examples of parameters related to the amount of water in blood include Ht value, electrical resistance value, and osmotic pressure. Note that the body fluid indices acquired by the monitoring device 200 may also include, for example, oral humidity, moisture content on the tongue, electrical resistance value (impedance) as a substitute parameter for the hydration status of the tongue, biological components related to body fluid balance (hormones related to diuresis such as vasopressin and aldosterone, electrolytes such as Na ions related to osmotic pressure, and the BUN / creatinine ratio as an index related to body fluid filtration).

[0044] The monitoring device 200 is not limited to a device configured to be attachable to the oral cavity O. The monitoring device 200 may be, for example, a device configured to be able to acquire humidity in the nasal cavity or paranasal sinuses, a device configured to acquire blood flow around the location where the stimulation unit 110 is placed near the esophagus E, a device configured to acquire the amount of water passing through the esophagus E, a device configured to measure the presence or absence of stomach contents by ultrasound, or the like.

[0045] Furthermore, the monitoring device 200 may be configured to detect the movement of markers placed on the support structure 120 or the stimulation unit 110, and calculate the frequency of peristaltic movement from the detection results. When the monitoring device 200 is configured in this manner, the control unit 300 can detect the peristaltic movement of the esophagus E associated with the subject's ingestion of food, etc., using the monitoring device 200, and measure the meal interval from the detection results. The control unit 300 can store the measured meal interval, and control the operation of the stimulation unit 110 so as to apply stimulation at a time that is offset from this meal interval.

[0046] The control unit 300 includes a CPU, a memory unit, and a power supply unit. The memory unit includes a ROM for storing various programs and data, a RAM for temporarily storing programs and data as a working area, and a hard disk capable of storing various programs and data.

[0047] The storage unit included in the control unit 300 can store a series of programs required to control the stimulation unit 110 based on the monitoring results of the monitoring device 200. The power supply unit supplies a driving current to the stimulation unit 110.

[0048] The control unit 300 can store information related to the operation of the stimulation unit 110 and generate a stimulation pattern for each subject. The control unit 300 can also apply stimulation according to the generated pattern, acquire data on the extent to which saliva secretion was promoted as a result of the stimulation, and perform feedback control of the operation of the stimulation unit 110 based on the acquired data.

[0049] 1, in this embodiment, the control unit 300 is configured as a device separate from the medical device 100 and is placed outside the subject's body. However, the control unit 300 may be mounted on the medical device 100. Furthermore, the control unit 300 may be configured, for example, as an existing communication device or the like in which a dedicated program is installed.

[0050] <Control flow> 5 shows an example of a control flow of the medical system 10. The control flow will be described with reference to FIG.

[0051] When the control unit 300 receives an instruction from the subject (or medical professional) and starts a series of programs related to the application of stimuli, the monitoring device 200 starts monitoring changes in the body fluid index of the subject (step S11).

[0052] The monitoring device 200 acquires the body fluid indices (step S12). The time interval for acquiring the body fluid indices, the period for which acquisition of the body fluid indices continues, etc. can be set arbitrarily.

[0053] The control unit 300 determines whether or not to start providing a stimulus based on the body fluid index acquired by the monitoring device 200 (step S13). In this embodiment, the control unit 300 calculates the oral cavity wetness level based on the body fluid index acquired by the monitoring device 200. If the measured oral cavity wetness level exceeds a preset "target value for oral cavity wetness level" (step S13: YES), the control unit 300 does not provide a stimulus and continues monitoring the body fluid index (step S11).

[0054] If the subject's oral cavity wetness does not exceed the "target value of oral cavity wetness" (step S13: NO), the control unit 300 activates the stimulation unit 110 to apply stimulation (step S14). Note that the calculation formula for the oral cavity wetness and data related to the target value of the oral cavity wetness can be stored in advance in the memory unit of the control unit 300.

[0055] If the control unit 300 applies a stimulus in step S14, it acquires the body fluid index again via the monitoring device 200. The control unit 300 also recalculates the oral cavity wetness level based on the acquired body fluid index, and determines whether the oral cavity wetness level of the subject has reached the target value (step S15). If the oral cavity wetness level has not reached the target value (step S15: NO), it causes the stimulation unit 110 to apply a stimulus again (step S14). The control unit 300 repeats the acquisition of the body fluid index, the acquisition of the oral cavity wetness level, the comparison with the target value for the oral cavity wetness level, and the application of the stimulus until the oral cavity wetness level reaches the target value.

[0056] When the wetness in the oral cavity reaches the target value (step S15: YES), the control unit 300 stops applying the stimulus (step S16).

[0057] After the oral cavity wetness level reaches the target value, the control unit 300 continues monitoring using the monitoring device 200 as necessary (step S17). Furthermore, when an instruction is received from the subject (or a medical professional) while monitoring using the monitoring device 200 is being continued, the control unit 300 can execute the control flow related to the application of stimuli described above again.

[0058] The monitoring target of the monitoring device 200 may be a side effect of the applied stimulation. For example, a decrease in heart rate and cardiac output due to stimulation of the vagus nerve may be considered. By monitoring each of the above indicators, the control unit 300 can stop the stimulation if an undesirable reaction is detected. Furthermore, the monitored items may include, but are not limited to, tachycardia, bradycardia, changes in cardiac output, esophageal peristalsis, and the like. Furthermore, the monitoring results of the monitoring device 200 may be used to optimize the placement position of the medical device 100. For example, the applied stimulation and the resulting saliva secretion volume may be monitored to confirm that the stimulation unit 110 is placed in the optimal stimulation position. Furthermore, the monitored items may include, but are not limited to, bodily fluid indicators.

[0059] <Example of use of medical device 100> When a medical professional (e.g., a doctor) uses the medical device 100 to perform a procedure to stimulate saliva secretion in a subject, the medical device 100 is placed in the esophagus E of the subject. The medical device 100 can be delivered and placed in the esophagus E using, for example, a medical instrument for introduction into a living body (e.g., a sheath, etc.). Note that the medical professional can also use a balloon device or the like on which the medical device 100 is fitted, as needed. Furthermore, the medical device 100 may be deformed into a contracted or reduced-diameter state as needed until it is delivered to the placement position in the esophagus E.

[0060] A medical professional can deliver the medical device 100 into the esophagus E, for example, through the oral cavity O. As shown in FIG. 4 , the medical professional places the stimulation unit 110 of the medical device 100 between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E. The medical professional also supports the support structure 120 against the inner wall Ew of the esophagus E using the support unit 130 (first support unit 131, second support unit 132). With the stimulation unit 110 in contact with the inner wall Ew of the esophagus E, the medical professional can hold the stimulation unit 110 in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E. In this manner, with the medical device 100 placed in the esophagus E, stimulation is applied from the stimulation section 110 to the vagus nerve running under the mucosa of the esophagus E, thereby suppressing unnecessary stimulation to the recurrent laryngeal nerve and aortic arch around the first stenosis N1 of the esophagus E, and the diaphragm and sphincter muscles near the third stenosis of the esophagus E, while promoting saliva secretion in the subject.

[0061] As described above, the treatment method (method for promoting saliva secretion) according to this embodiment includes applying stimulation to the vagus nerve running under the mucosa of the esophagus E from the stimulation section 110 of the medical device 100 placed between the first stenosis N1 of the esophagus E and the second stenosis N2 of the esophagus E.

[0062] The treatment method also includes applying stimulation from the stimulation unit 110 while the support portion 130 of the medical device 100 holds the stimulation unit 110 in a fixed position between the first stenosis N1 of the esophagus E and the second stenosis N2 of the esophagus E.

[0063] The treatment method also includes holding the stimulation section 110 in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E by using a first support section 131 of the support section 130 positioned downstream of the second stenosis N2 of the esophagus E and a second support section 132 positioned downstream of the first support section 131 in the esophagus E and upstream of the third stenosis N3.

[0064] The above treatment method also includes the control unit 300 controlling one of the start, stop, and magnitude of stimulation by the stimulation unit 110 based on the body fluid indicators acquired by the monitoring device 200 attached to the subject.

[0065] The above treatment method can also be carried out for the purpose of controlling the body fluid volume of a patient with heart failure.

[0066] As described above, the medical device 100 of this embodiment has a stimulation section 110 that can stimulate the vagus nerve running under the mucosa of the esophagus E to promote saliva secretion, a support structure 120 in which the stimulation section 110 is arranged, and a support section 130 that supports the support structure 120 relative to the esophagus E, thereby holding the stimulation section 110 in a fixed position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E.

[0067] According to the medical device 100 configured as described above, the stimulation unit 110 arranged on the support structure 120 can be held fixedly in position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E. With the medical device 100 placed in the esophagus E, the stimulation unit 110 can stimulate the vagus nerve running under the mucosa of the esophagus E, thereby promoting saliva secretion in the subject. Furthermore, use of the medical device 100 can prevent stimulation from being applied to the area around the first stenosis N1 of the esophagus E and the area around the third stenosis N3 of the esophagus E, thereby reducing the burden on the subject.

[0068] The support structure 120 has a first opening 121a formed at one longitudinal end 121, a second opening 122a formed at the other longitudinal end 122, and an inner cavity 125 extending in the longitudinal direction, and has a mesh-like structure that can deform to follow the movement of the esophagus E while being held within the esophagus E.

[0069] The medical device 100 configured as described above can move food or the like from the pharynx side to the stomach S side through the first opening 121a, the lumen 125, and the second opening 122a of the support structure 120, even when the subject ingests food or the like with the medical device 100 placed in the esophagus E. Therefore, the subject can ingest food or the like with the medical device 100 placed in the esophagus E, and can live a normal life. Furthermore, because the support structure 120 has a mesh structure that can deform in accordance with the movement of the esophagus E, it is possible to prevent the subject from feeling uncomfortable with the medical device 100 placed in the esophagus E. Furthermore, the support structure 120, which has a mesh structure, can prevent the movement of the esophagus E from being obstructed.

[0070] The support portion 130 has a first support portion 131 and a second support portion 132 that is disposed at a position on the downstream side of the esophagus E relative to the first support portion 131.

[0071] The medical device 100 configured as described above can support the support structure 120 at least at two positions in the extension direction of the esophagus E. Therefore, the medical device 100 can be held in the esophagus E more stably.

[0072] The first support portion 131 is positioned so as to abut against the inner wall Ew of the esophagus E at a position downstream of the second stenosis N2 of the esophagus E, and the second support portion 132 is positioned so as to abut against the inner wall Ew of the esophagus E at a position upstream of the third stenosis N3 of the esophagus E.

[0073] The medical device 100 configured as described above can more securely hold the stimulation section 110 arranged on the support structure 120 between the first stenosis N1 of the esophagus E and the second stenosis N2 of the esophagus E by using the first support section 131 and the second support section 132.

[0074] The first support portion 131 is configured at one end portion 121 of the support structure 120 in the longitudinal direction, and the second support portion 132 is configured at the other end portion 122 of the support structure 120 in the longitudinal direction.

[0075] In the medical device 100 configured as described above, the support portions 131, 132 are configured integrally with the support structure 120, thereby simplifying the device configuration of the medical device 100. Furthermore, because the entire support structure 120 can be held between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E, it is possible to prevent the support structure 120 from coming into contact with the peripheral areas of the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E when the medical device 100 is placed in the esophagus E. This prevents unnecessary stimulation from being applied to the peripheral areas of the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E.

[0076] At least a portion of the support portion 130 has a tapered shape that widens in the radial direction away from the central axis C1 side of the support structure 120.

[0077] The medical device 100 configured as described above can bring the support parts 130 protruding radially from the support structure 120 into contact with the inner wall Ew of the esophagus E. This increases the support force of the support structure 120 against the esophagus E. Furthermore, when the support parts 131, 132 are formed by the ends 121, 122 of the support structure 120, food and the like that has moved from the pharynx side to the stomach S side can be smoothly moved into the lumen 125 of the support structure 120 via the tapered first opening 121a, and can also be smoothly moved from the lumen 125 of the support structure 120 to the stomach S side via the tapered second opening 122a.

[0078] The medical system 10 of this embodiment includes a medical device 100, a monitoring device 200 that acquires body fluid indicators of a subject to which the medical device 100 is attached, and a control unit 300 that controls the operation of the stimulation unit 110 based on the body fluid indicators acquired by the monitoring device 200.

[0079] The medical system 10 configured as described above can determine the breathing condition of the subject based on the body fluid indicators of the subject acquired by the monitoring device 200, and then control the operation of the stimulation unit 110. Therefore, it becomes possible to apply stimulation at an appropriate timing according to the breathing condition of the subject.

[0080] Modified examples and other embodiments will be described below. In the following description, explanations of content that overlaps with content already explained in the medical device 100 according to the first embodiment will be omitted. Furthermore, components and the like that are not specifically explained can be the same as those in the medical device 100 according to the first embodiment.

[0081] <Modification 1 of the First Embodiment> 6 shows a state in which a medical device 100A according to Modification 1 is placed in the esophagus E. The medical device 100A according to Modification 1 differs from the medical device 100 described above in the structure of the support parts (first support part 131, second support part 132).

[0082] 6, the first support portion 131 and the second support portion 132 have a convex shape curved in a radial direction away from the central axis C1 of the support structure 120. Specifically, the first support portion 131 has a curved shape that can be placed along the protruding portion of the inner wall Ew that forms the second stricture N2 of the esophagus E. Furthermore, the second support portion 132 has a curved shape that can be placed along the protruding portion of the inner wall Ew that forms the third stricture N3 of the esophagus E.

[0083] The first support portion 131 is configured at one end portion 121 of the support structure 120. The first support portion 131 can be disposed at a position in the esophagus E downstream of the second stricture N2.

[0084] The second support portion 132 is configured at the other end 122 of the support structure 120. The second support portion 132 can be disposed in the esophagus E at a position upstream of the third stricture N3.

[0085] As with the medical device 100 described above, the medical device 100A according to the first modification allows the support structure 120 to be suitably placed in the esophagus E by the first support portion 131 and the second support portion 132 provided on the support structure 120. Also, as shown in FIG. 6 , the stimulation portion 110 arranged on the support structure 120 can be held fixedly in position between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E. Furthermore, since each of the support portions 131 and 132 has a curved shape that can be positioned along the protruding portion of the inner wall Ew that forms the second stenosis N2 of the esophagus E and the protruding portion of the inner wall Ew that forms the third stenosis N3 of the esophagus E, the load on the esophagus E can be reduced more than in the medical device 100 according to the first embodiment.

[0086] <Modification 2 of the First Embodiment> 7 shows a state in which a medical device 100B according to Modification 2 is placed in the esophagus E. The medical device 100B according to Modification 2 differs from the medical device 100 described above in the structures of the support structure 120 and the support portion.

[0087] As shown in FIG. 7, the medical device 100B has a first support portion 131, a second support portion 132, and a third support portion 133.

[0088] The first support part 131 is configured as part of the intermediate part 123 of the support structure 120. The first support part 131 can be placed at a position downstream of the second stricture N2 of the esophagus E. The first support part 131 has a curved shape that can be placed along the protruding portion of the inner wall Ew that forms the second stricture N2 of the esophagus E.

[0089] The second support part 132 is configured at the other end 122 of the support structure 120. The second support part 132 can be placed at a position upstream of the third stricture N3 of the esophagus E. The second support part 132 has a curved shape that can be placed along the protruding portion of the inner wall Ew that forms the third stricture N3 of the esophagus E.

[0090] The third support part 133 is configured at one end part 121 of the support structure 120. The third support part 133 can be disposed at a position upstream of the second stricture N2 of the esophagus E. The third support part 133 can also be disposed so as to abut against a protruding part of the inner wall Ew that forms the second stricture N2 of the esophagus E. The third support part 133 can be formed, for example, in a tapered shape that widens in the radial direction away from the central axis C1 side of the support structure 120.

[0091] The medical device 100B can support the support structure 120 with respect to the esophagus E with the three support portions 131, 132, and 133, and therefore can hold the medical device 100B more stably in the esophagus E. Furthermore, as shown in FIG. 7 , when the medical device 100B is placed in the esophagus E, the third support portion 133 sandwiches the protruding portion of the inner wall Ew that forms the second stenosis N2 of the esophagus E between the first support portion 131 and the third support portion 133. This improves the supporting force of the support structure 120 near the second stenosis N2 of the esophagus E. This allows the stimulation portion 110 disposed on the support structure 120 to be more reliably held between the second stenosis N2 of the esophagus E and the third stenosis N3 of the esophagus E.

[0092] Second Embodiment Fig. 8 shows a medical device 100C according to the second embodiment. Fig. 9 shows a schematic cross-sectional view of the medical device 100C placed in the esophagus E. Fig. 11 shows a schematic partial cross-sectional view (transverse cross-section) of the esophagus E with the medical device 100C placed.

[0093] The medical device 100C according to the second embodiment differs from the medical device 100 described above in the structures of the support structure 120 and the stimulation section 110.

[0094] As shown in FIG. 8, the support structure 120 has a first portion 120A, a second portion 120B, and a third portion 120C that connects the first portion 120A and the second portion 120B.

[0095] As shown in FIG. 9, when the medical device 100C is placed in the esophagus E, the first portion 120A is located at a position on the upstream side of the esophagus E relative to the second portion 120B.

[0096] The first support part 131 is configured by an end part located on the pharynx side of the first part 120A that forms one end part 121 of the support structure 120. The second support part 132 is configured by an end part located on the stomach S side of the second part 120B that forms the other end part 122 of the support structure 120.

[0097] 8, third part 120C connects an end of first part 120A located on the second part 120B side with an end of second part 120B located on the first part 120A side. Note that there are no particular restrictions on the positions of first part 120A and second part 120B to which third part 120C is connected. Furthermore, methods such as adhesion and welding can be used as a connection method.

[0098] In this embodiment, the third section 120C is made up of a plurality of stimulation sections 111 arranged along the circumferential direction of the support structure 120 with gaps between them.

[0099] The multiple stimulation units 111 are arranged with gaps between them in the circumferential direction of the support structure 120. Therefore, the area of ​​the portion of the support structure 120 where the third portion 120C is arranged is smaller on the outer circumferential surface of the support structure 120 than the first portion 120A and the second portion 120B by the amount of the gap. Therefore, when the medical device 100C is placed in the esophagus E, the area of ​​contact between the third portion 120C and the inner wall Ew of the esophagus E is smaller than the area of ​​the first portion 120A and the second portion 120B.

[0100] The mesh structure constituting the first portion 120A and the second portion 120B may be disposed in the third portion 120C. When a mesh structure is disposed in the third portion 120C, it is preferable that the mesh in the third portion 120C be coarser than those in the first portion 120A and the second portion 120B.

[0101] There are no particular limitations on the number and shape of the stimulation units 111 and the size of the gaps formed between the stimulation units 111. However, it is preferable that the gaps formed between the stimulation units 111 be formed to a size that prevents food and the like passing through the lumen 125 of the support structure 120 from excessively flowing out of the support structure 120.

[0102] As will be described later, the stimulation unit 111 is preferably formed in a vertically elongated shape along the longitudinal direction of the support structure 120 so that it can easily enter the pleated portion of the inner wall Ew of the esophagus E. Furthermore, the cross section of the stimulation unit 111 can be formed, for example, in a circular shape.

[0103] In this embodiment, the stimulation units 111 have substantially the same shape. However, the stimulation units 111 may have different shapes. For example, the stimulation units 111 may be arranged substantially linearly along the extension direction of the support structure 120. For example, the stimulation units 111 may be arranged substantially parallel to each other.

[0104] The stimulation unit 111 can be configured, for example, with a metal electrode capable of applying an electrical stimulus. However, the stimulation unit 111 can be selected from any structure and material depending on the type of stimulus to be applied.

[0105] As shown in Figure 9, when the medical device 100C is placed, the multiple stimulation sections 111 that make up the third region 120C are held in a fixed position between the second stricture N2 of the esophagus E and the third stricture N3 of the esophagus E.

[0106] FIG. 10 shows a partial cross-sectional view of the esophagus E when food or the like is not passing through. When food or the like is not passing through, the inner wall Ew of the esophagus E has a pleated shape with an uneven cross section. When the medical device 100C is placed in the esophagus E, each of the multiple stimulation units 111, which are arranged with gaps between them in the circumferential direction of the esophagus E, is arranged so as to enter the pleated recesses of the inner wall Ew of the esophagus E, as shown in FIG. 10. By activating the stimulation units 111 with the stimulation units 111 arranged in each pleated recess of the inner wall Ew of the esophagus E, it is possible to more efficiently stimulate the vagus nerve running under the mucosa of the esophagus E. Therefore, by using the medical device 100C according to the third modification, it is possible to more effectively stimulate saliva secretion in the subject.

[0107] <Modification 1 of the Second Embodiment> FIG. 11 shows a medical device 100D according to a first modification of the second embodiment.

[0108] In medical device 100D according to Modification 1, each of the plurality of stimulation sections 111 constituting third region 120C is arranged at an angle with respect to the longitudinal direction of support structure 120. Furthermore, each of the plurality of stimulation sections 111 is made of a member having a smaller area than stimulation section 111 (see FIG. 8) of medical device 100C described above. As shown in this modification, there are no particular limitations on the shape, arrangement direction, number, etc. of stimulation sections 111 constituting third region 120C, and these can be changed as desired.

[0109] <Modification 2 of the Second Embodiment> Fig. 12 shows a medical device 100E according to Modification 2 of the second embodiment. Fig. 13 shows a schematic cross-sectional view of the medical device 100E placed in the esophagus E.

[0110] A medical device 100E according to the second modification differs from the above-described medical device 100C in the structure of a third portion 120C of a support structure 120.

[0111] As shown in FIG. 12, the third region 120C has a plurality of stimulation portions 111 and a linear member 150.

[0112] The linear member 150 is disposed between the first portion 120A and the plurality of stimulation units 111. As shown in Fig. 13 , when the medical device 100E is placed in the esophagus E, the linear member 150 is disposed at a position upstream of the plurality of stimulation units 111 in the esophagus E.

[0113] The linear member 150 is wound around the circumferential direction of the support structure 120 and extends in the extension direction of the support structure 120. The linear member 150 can be arranged, for example, in a spiral shape around the central axis C1 of the support structure 120. There are no particular limitations on the winding shape, number of turns, cross-sectional shape, etc. of the linear member 150.

[0114] The linear member 150 can be made of, for example, a flexible material that can expand and contract in the longitudinal and circumferential directions of the support structure 120. The material that can be used to make the linear member 150 is, for example, a superelastic alloy such as a nickel-titanium alloy.

[0115] As shown in FIG. 13, the medical device 100E can be placed, for example, between a first stricture N1 of the esophagus E and a third stricture N3 of the esophagus E.

[0116] The first portion 120A can be located downstream of the first stricture N1 of the esophagus E and between the first stricture N1 of the esophagus E and the second stricture N2 of the esophagus E. The second portion 120B can be located downstream of the second stricture N2 of the esophagus E and upstream of the third stricture N3 of the esophagus E.

[0117] The first support portion 131 provided in the first region 120A can be positioned so as to abut against a protruding portion of the inner wall Ew that forms the first stricture N1 of the esophagus E. The second support portion 132 provided in the second region 120B can be positioned so as to abut against a protruding portion of the inner wall Ew that forms the third stricture N3 of the esophagus E.

[0118] The plurality of stimulation units 111 constituting the third region 120C can be arranged between the second stricture N2 of the esophagus E and the third stricture N3 of the esophagus E. The plurality of stimulation units 111 can be arranged so as to enter the recesses of the fold-like portion formed by the inner wall Ew of the esophagus E (see FIG. 10).

[0119] The linear member 150 constituting the third section 120C can extend from a position in the esophagus E upstream of the second stricture N2 to a position in the esophagus E downstream of the second stricture N2.

[0120] The portion of the support structure 120 where the linear member 150 is arranged has a smaller area of ​​contact with the inner wall Ew of the esophagus E than the first portion 120A and the second portion 120B. Therefore, even if the linear member 150 comes into contact with the second stenosis N2 when the medical device 100E is placed in the esophagus E as shown in Fig. 13 , it is possible to reduce irritation occurring in the periphery of the second stenosis N2. Therefore, even if the medical device 100E is placed in the esophagus E with the first portion 120A, on which the first support portion 131 is provided, positioned upstream of the second stenosis N2 in the esophagus E, it is possible to reduce the load on the subject's body.

[0121] The third portion 120C connecting the first portion 120A and the second portion 120B may be formed only by the linear member 150 described in the second modification.

[0122] The above describes the medical device, medical system, and treatment method according to the present invention based on each embodiment and each modified example. However, the present invention is not limited to the embodiments and modified examples described in the specification, and various modifications are possible within the scope of the claims.

[0123] For example, the medical device may be any combination of the configurations described in the respective embodiments and modifications. Furthermore, the structure, material, size, etc. of each part of the medical device may be changed as desired as long as it can stimulate the vagus nerve running under the mucous membrane of the esophagus and promote saliva secretion.

[0124] This application is based on Japanese Patent Application No. 2020-136237, filed on August 12, 2020, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0125] 10. Healthcare System 100, 100A, 100B, 100C, 100D, 100E Medical Devices 110 Stimulation part 111 Multiple Stimulation Areas 120 Support structure 120A First part of support structure 120B Second portion of support structure 120C Third section of support structure 121 one end of support structure 121a First opening in support structure 122 other end of support structure 122a Second opening in support structure 123 Middle part of support structure 125 Lumen of support structure 130 Support part 131 1st support part 132 Second support part 133 Third support part 150 Linear members 200 Monitoring Devices 300 control section M1, M2, M3, M4 markers E esophagus Ew: Inner wall of the esophagus L. Lumen of the esophagus N1 First stenosis of the esophagus N2 Secondary esophageal stricture N3 Third stenosis of the esophagus O oral cavity S stomach

Claims

1. a stimulation unit capable of applying stimulation to the vagus nerve running under the mucosa of the esophagus to promote saliva secretion; a support structure on which the stimulation unit is disposed; a support portion that supports the support structure against the esophagus, thereby holding the stimulation portion in a fixed position between the second esophageal constriction and the third esophageal constriction; The support portion is A first support portion; a second support portion disposed at a position downstream of the esophagus relative to the first support portion, the first support portion is disposed so as to abut against an inner wall of the esophagus at a position downstream of the second stricture in the esophagus, the second support portion is disposed so as to abut against an inner wall of the esophagus at a position upstream of the third stricture, A medical device in which the support structure is supported against the esophagus by the abutment of the first support part against the inner wall of the esophagus and the abutment of the second support part against the inner wall of the esophagus, thereby holding the stimulation part arranged on the support structure in a fixed position.

2. The support structure includes:

2. The medical device according to claim 1, having a first opening formed at one end in the longitudinal direction, a second opening formed at the other end in the longitudinal direction, and an inner cavity extending in the longitudinal direction, and comprising a mesh-like structure that is deformable to follow the movement of the esophagus while being held within the esophagus.

3. the first support portion is configured at one end portion in the longitudinal direction of the support structure, The medical device according to claim 1 or 2, wherein the second support portion is configured at the other longitudinal end of the support structure.

4. The medical device according to any one of claims 1 to 3, wherein the support portion has a third support portion that is positioned upstream of the esophagus relative to the first support portion.

5. The medical device according to any one of claims 1 to 4, wherein at least a portion of the support portion has a tapered shape that widens in a radial direction away from the central axis of the support structure.

6. The medical device according to any one of claims 1 to 5, wherein at least a portion of the support portion has a convex shape curved in a radial direction away from the central axis of the support structure.

7. The support structure includes: A first portion; a second portion disposed downstream of the esophagus relative to the first portion; The medical device according to any one of claims 1 to 6, further comprising: a third portion that connects the first portion and the second portion and is formed so as to have a smaller area on the outer surface of the support structure than the first portion and the second portion.

8. The medical device of claim 7 , wherein the third region has a plurality of the stimulation portions spaced apart from one another along the circumferential direction of the support structure.

9. The medical device according to claim 7 or 8, wherein the third portion comprises a linear member wound around a central axis of the support structure.

10. The medical device according to any one of claims 1 to 9, comprising a marker that enables the position of the support structure and / or the stimulation portion to be confirmed.

11. A medical device according to any one of claims 1 to 10; a monitoring device for acquiring a body fluid indicator of a subject to which the medical device is attached; A medical system comprising: a control unit that controls operation of the stimulation unit based on the body fluid indicator acquired by the monitoring device.

12. a control unit controlling the operation of the stimulation unit of a medical device comprising: a stimulation unit capable of applying stimulation to a vagus nerve running under the mucosa of the esophagus to promote saliva secretion; a support structure on which the stimulation unit is disposed; and a support unit that supports the support structure relative to the esophagus to hold the stimulation unit in a fixed position between a second stenosis of the esophagus and a third stenosis of the esophagus, the support unit having a first support unit and a second support unit disposed at a position downstream of the esophagus relative to the first support unit, the first support unit being disposed so as to abut against an inner wall of the esophagus at a position downstream of the second stenosis, and the second support unit being disposed so as to abut against an inner wall of the esophagus at a position upstream of the third stenosis, the support structure being supported relative to the esophagus by the abutment of the first support unit against the inner wall of the esophagus and the abutment of the second support unit against the inner wall of the esophagus, A method for operating a medical device, wherein the control unit controls the operation of the stimulation unit, which is positioned between the second stenosis of the esophagus and the third stenosis of the esophagus of the subject, so that stimulation is applied from the stimulation unit to the vagus nerve running under the mucosa of the esophagus.

13. The control unit A method for operating a medical device as described in claim 12, including controlling any one of the start, stop, and magnitude of stimulation by the stimulation unit based on body fluid indicators acquired by a monitoring device attached to the subject.

14. The control unit The method for operating a medical device according to claim 12 or 13, wherein the operation of the stimulation unit is controlled so that saliva secretion is promoted in a patient with heart failure by the stimulation unit applying stimulation to the vagus nerve in the patient with heart failure.

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