Vascular monitoring system

Abstract

A vessel monitoring system includes a collar configured to be positioned about a vessel of a patient; and a transducer coupled to the collar. The collar may be formed from a strap that is wrapped around the blood vessel of the patient and maintained in a closed configuration. The transducer is configured to emit an ultrasonic signal transmitted through a blood vessel of a patient.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202180007710.5, filed on January 8, 2021, entitled “VASCULAR MONITORING COLLAR” and having the same assignee herewith. This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62 / 959,587, filed January 10, 2020, entitled “VASCULAR MONITORING COLLAR” and U.S. Provisional Patent Application No. 63 / 037,772, filed June 11, 2020, entitled “VASCULAR MONITORING COLLAR,” the entire contents of both applications are incorporated herein by reference. BACKGROUND

[0002] Reconstructive and reconstructive surgeries, such as in chest reconstruction, often use free flaps. In free flap tissue surgery, a free flap (e.g., tissue and / or muscle and its associated arteries and veins) is removed from one part of the body or donor site and reattached to another part of the body or recipient site. The arteries and veins of the transplanted tissue and / or muscle are then anastomosed with the native arteries and veins to achieve blood circulation in the transplanted free flap (e.g., tissue and / or muscle).

[0003] Anastomosis of free flap tissue with native tissue is often accomplished using microvascular techniques, including under a microscope. Over the years, several surgical instruments and techniques have been developed to assist in performing anastomosis. One known system for creating anastomosis is the anastomosis coupler described in U.S. Patent No. 7,192,400, the disclosure of which is incorporated herein by reference. This anastomosis coupler is a surgical instrument that enables a surgeon to more easily and effectively join two blood vessel ends together. These couplers involve the use of two looped fastener portions to secure respective portions of the blood vessels to be attached on the fastener portions. Each fastener portion is also provided with a series of pins and corresponding holes for receiving the pins to close and connect the portions, and thus the blood vessels, together.

[0004] While free flap surgery has a history of success, the highly undesirable consequences of flap failure still exist. One of the main causes of flap failure is the lack of blood supply to the flap tissue after the free flap is reattached at the recipient site. Factors that typically disrupt circulation in the flap include vessel occlusion, hemorrhage, or infection. When there is not enough blood supply to the flap tissue, tissue necrosis results. However, if the flap is not getting enough circulation can be recognized early, the flap can be saved or salvaged. The window of time to salvage the flap after recognizing insufficient blood flow is very small. Therefore, it is critical to quickly recognize any blood flow insufficiency in a transplanted flap.

[0005] Handheld Doppler probes, which are typically permanently located at the distal tip of a pen-like device, rather than placed or left in the body, have helped with blood flow monitoring, but they have some drawbacks. One drawback of handheld probes is that they cannot be reliably positioned around a blood vessel.

[0006] Monitoring the surgical area after microvascular surgery is important to ensure that blood flow is maintained at a desired level and that problems such as thrombosis do not occur. If a thrombosis occurs, the transplanted tissue dies. Other indirect means of monitoring blood flow function through a blood vessel that has been subjected to microvascular surgery are also often inadequate. For example, surface temperature measurements, transcutaneous PO2 monitoring, photoplethysmography, and laser Doppler flowmetry have been employed. However, these methods often require an accessible exposed portion of the flap. Additionally, these methods cannot effectively monitor buried free tissue transplants and intraoral flaps. SUMMARY

[0007] The present disclosure provides improved vascular monitoring tourniquets and collars that can be used with vascular monitoring systems, devices, and methods to improve the accessibility, detection, and / or reliability of detecting blood flow to confirm patency of a blood vessel at an anastomosis site.

[0008] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a first example aspect of the disclosure, a vascular monitoring system includes a collar configured to be positioned around a blood vessel of a patient, and a transducer coupled to the collar. The transducer is configured to emit an ultrasonic wave signal that is transmitted through the blood vessel of the patient.

[0009] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the collar includes at least one eyelet adapted to be sutured to adjacent tissue to fixedly position the collar around the blood vessel of the patient.

[0010] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar includes a probe holder sized and shaped to receive the transducer.

[0011] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is coupled to the collar by a friction fit with the probe holder.

[0012] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is made of at least one of implant grade liquid silicone rubber ("LSR") and high consistency silicone rubber ("HCR") having a hardness between 40 and 80.

[0013] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is configured to be positioned around an anastomosis site of a blood vessel of the patient.

[0014] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is configured to be positioned at a location that is one of upstream of an anastomosis site of a blood vessel of the patient and downstream of the anastomosis site of the blood vessel of the patient.

[0015] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is removably coupled to the collar.

[0016] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a second exemplary aspect of the present disclosure, a vessel collar includes a cylindrical body portion having an opening with an inner diameter sized and shaped to be positioned around a blood vessel of a patient. The vessel collar also includes a probe holder and at least one mounting tab. The probe holder is configured to receive a transducer.

[0017] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the inner diameter is between 1.0 mm and 4.0 mm.

[0018] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is configured to emit an ultrasonic signal that is transmitted through the blood vessel of the patient.

[0019] Aspects of the subject matter described herein can be used separately or in combination with one or more other aspects described herein. In a third example aspect of the present disclosure, a vessel monitoring system includes a collar configured to be positioned around a blood vessel of a patient. The collar is configured to transition from an open configuration to a closed configuration. The vessel monitoring system further includes a transducer coupled to the collar. The transducer is configured to emit ultrasound signals that are transmitted through the blood vessel of the patient.

[0020] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar includes at least one closure structure configured to maintain the collar in the closed configuration.

[0021] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the at least one closure structure includes a first eyelet and a second eyelet.

[0022] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the at least one closure structure is adapted to be sutured to adjacent tissue to fixedly position the collar around the blood vessel of the patient.

[0023] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar includes a probe holder sized and shaped to receive the transducer.

[0024] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is coupled to the collar by a friction fit with the probe holder.

[0025] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is made of at least one of implant grade liquid silicone rubber (“LSR”) and high consistency silicone rubber (“HCR”) having a hardness between 40 and 80.

[0026] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is configured to be positioned around an anastomosis site of the blood vessel of the patient.

[0027] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is configured to be positioned at a location that is one of upstream of an anastomosis site of the blood vessel of the patient and downstream of the anastomosis site of the blood vessel of the patient.

[0028] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is removably coupled to the collar.

[0029] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a fourth example aspect of the present disclosure, a vessel collar includes a body portion configured to transition from an open configuration to a closed configuration. The body portion has an opening in the closed configuration, and the opening has an inner diameter sized and shaped to be positioned around a blood vessel of a patient. The vessel collar further includes a probe holder and at least one mounting tab. The probe holder is configured to receive a transducer.

[0030] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the mounting tab includes a closure feature adapted to retain the collar in the closed configuration after the collar is transitioned from the open configuration to the closed configuration.

[0031] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the body portion is made of a flexible / resilient material that allows the body portion to transition from the open configuration to the closed configuration when a closing force is applied to the collar.

[0032] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a fifth example aspect of the present disclosure, a vessel monitoring system includes a band configured to be positioned around a blood vessel of a patient, a clasp configured to maintain the band in a closed configuration around the blood vessel of the patient, and a transducer coupled to the band. The transducer is configured to emit an ultrasonic signal that is transmitted through the blood vessel of the patient.

[0033] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the band includes at least one eyelet adapted to be sutured to adjacent tissue to fixedly position the band around the blood vessel of the patient.

[0034] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the band includes a probe holder sized and shaped to receive the transducer.

[0035] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is coupled to the band by a friction fit with the probe holder.

[0036] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the band is made of at least one of implant grade liquid silicone rubber ("LSR"), high consistency silicone rubber ("HCR"), high density polyethylene ("HDPE"), Nusil 4750, Nusil 4840, and thermoplastics.

[0037] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the band is configured to be positioned around an anastomosis site of a blood vessel of the patient in its closed configuration.

[0038] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the band is configured to be positioned at a location that is one of upstream of an anastomosis site of a blood vessel of the patient and downstream of the anastomosis site of the blood vessel of the patient in its closed configuration.

[0039] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is removably coupled to the collar.

[0040] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a sixth exemplary aspect of the present disclosure, a vascular band includes an elongated band body having a first end and a second end, a plurality of sized holes positioned along the band body proximate the first end, and a closure peg positioned proximate the second end of the band body. The closure peg is sized and shaped to press fit through one of the plurality of sized holes, and the closure peg is configured to maintain the vascular band in a closed configuration when press fit through the sized hole. The closed configuration forms a cylindrical shape having an inner diameter sized and shaped to be positioned around a blood vessel of a patient. Additionally, the vascular band includes a probe holder and at least one mounting tab. The probe holder is configured to receive a transducer.

[0041] According to another exemplary aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the inner diameter is between 1.0 mm and 4.0 mm.

[0042] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is configured to emit ultrasound signals transmitted through a blood vessel of the patient.

[0043] Aspects of the subject matter described herein can be used alone or in combination with one or more other aspects described herein. In a seventh example aspect of the present disclosure, a vessel monitoring system includes a strap configured to transition from an open configuration to a closed configuration. The strap forms a collar when placed in the closed configuration, the collar being configured to be positioned around a blood vessel of a patient. The vessel monitoring system also includes a transducer coupled to the collar. Additionally, the transducer is configured to emit ultrasound signals transmitted through a blood vessel of the patient.

[0044] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the strap includes at least one closure structure configured to maintain the strap in the closed configuration.

[0045] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the at least one closure structure includes a clamp, a clasp, and a band.

[0046] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the at least one closure structure includes a prong and a sized hole.

[0047] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the strap includes a probe holder sized and shaped to receive the transducer.

[0048] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is coupled to the strap by a friction fit with the probe holder.

[0049] According to another example aspect of the present disclosure, which can be used in combination with any one or more of the preceding aspects, the strap is made of at least one of implant grade liquid silicone rubber (“LSR”), high consistency silicone rubber (“HCR”), high density polyethylene (“HDPE”), Nusil 4750, Nusil 4840, and a thermoplastic.

[0050] Aspects of the subject matter described herein can be used separately or in combination with one or more other aspects described herein. In an eighth example aspect of the disclosure, a vascular cuff includes a base and a saddle extending from the base. The saddle has a proximal end and two respective distal ends. The vascular cuff also includes two respective strap portions extending from the respective distal ends of the saddle. The saddle and the two respective strap portions are sized and shaped to be positioned around a blood vessel of a patient. Additionally, the vascular cuff includes a probe holder formed within the base, the probe holder configured to receive a transducer.

[0051] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the transducer is configured to emit ultrasound signals that are transmitted through the blood vessel of the patient.

[0052] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the vascular cuff includes at least one eyelet adapted to be sutured to adjacent tissue to fixedly position the cuff around the blood vessel of the patient.

[0053] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the probe holder includes a receptacle sized and shaped such that the transducer is coupled to the cuff by a friction fit with the receptacle of the probe holder.

[0054] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the collar is made of at least one of implant grade liquid silicone rubber (“LSR”) and high consistency silicone rubber (“HCR”) having a hardness between 40 and 80.

[0055] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the saddle and the two respective strap portions are sized such that, when the vascular cuff is closed to form a collar around a blood vessel, an inner diameter of the collar is between 1.0 mm and 4.0 mm.

[0056] According to another example aspect of the disclosure, which can be used in combination with any one or more of the preceding aspects, the cuff includes at least one closure structure configured to maintain the cuff in the closed configuration.

[0057] Accordingly, one advantage of the disclosure is to improve accessibility of blood flow data.

[0058] Another advantage of the present disclosure is to improve detection of blood flow to confirm patency of a blood vessel.

[0059] Another advantage of the present disclosure is to provide remote monitoring of blood flow at an anastomosis site.

[0060] Yet another advantage of the present disclosure is to reduce the occurrence of free flap failure and serious adverse events due to insufficient blood flow in a free flap.

[0061] Another advantage of the present disclosure is to provide a system, device, and / or method for early detection of insufficient blood flow or circulation in a free flap.

[0062] Additional features and advantages of the disclosed vessel monitoring cuff will be described in the detailed description and in the drawings, and will be apparent from the detailed description and the drawings. The features and advantages described herein are not all-inclusive and many additional features and advantages will be readily apparent to those of ordinary skill in the art in view of the drawings and description, also, any particular embodiment does not have to have all of the advantages listed herein. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and not to limit the scope of the inventive subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a schematic view of a probe lead system according to one example embodiment of the present disclosure.

[0064] Figure 2 is a perspective view of a vessel cuff according to one example embodiment of the present disclosure with a transducer coupled to the cuff.

[0065] Figure 3A 、 Figure 3B and Figure 3C illustrate a vessel cuff and transducer positioned around a patient's blood vessel according to one example embodiment of the present disclosure.

[0066] Figure 4A is a perspective view of another example vessel cuff in an open configuration according to one example embodiment of the present disclosure with a transducer coupled to the cuff.

[0067] Figure 4B is a perspective view of the vessel cuff of Figure 4A in a closed configuration according to one example embodiment of the present disclosure.

[0068] Figure 5A 、 Figure 5B and Figure 5C illustrate a vessel cuff and transducer positioned around a patient's blood vessel according to one example embodiment of the present disclosure.

[0069] Figure 6 is a perspective view of a vascular cuff forming a vascular collar according to one example embodiment of the present disclosure.

[0070] Figure 7A is a perspective view of a vascular cuff forming a vascular collar according to one example embodiment of the present disclosure.

[0071] Figure 7B is an elevational view of a vascular cuff forming a vascular collar according to one example embodiment of the present disclosure.

[0072] Figure 7C is a cross-sectional view of the vascular cuff of Figure 7B along line 7C-7C.

[0073] Figure 8A and Figure 8B shows a vascular cuff and transducer positioned around a patient's blood vessel to form a vascular collar according to one example embodiment of the present disclosure.

[0074] Figure 9A and Figure 9B shows a vascular cuff and transducer positioned around a patient's blood vessel to form a vascular collar according to one example embodiment of the present disclosure. DETAILED DESCRIPTION

[0075] As described above, a vascular monitoring collar is provided to improve the accessibility, detection, and / or reliability of detecting blood flow to confirm vascular patency at an anastomosis site. While free flap surgery has a history of success, the highly undesirable consequences of flap failure still exist. One of the main causes of flap failure is the lack of blood supply to the flap tissue after the free flap is reattached at the recipient site. Factors that typically disrupt circulation in the flap include vascular occlusion, hemorrhage, or infection. When there is not enough blood supply to the flap tissue, it can lead to tissue necrosis. However, the vascular monitoring collar disclosed herein advantageously enables early detection of insufficient blood flow or circulation in the free flap so that the free flap can be saved or salvaged before tissue necrosis.

[0076] The aforementioned vascular monitoring loop can be used to monitor blood flow at, upstream of, or downstream of the anastomosis site to confirm vascular patency in surgical procedures such as free flap transplantation for microvascular reconstruction. This loop can be used in conjunction with monitoring systems in various settings, such as hospital operating rooms or post-anesthesia care units, to detect blood flow and confirm vascular patency (on-site or remotely) during and after surgery. Free flap transplantation can be used to reconstruct body parts from cancer and injury using the patient's own tissue. Examples include post-traumatic chest reconstruction, tongue reconstruction, jaw and cheek reconstruction, hand and foot reconstruction, etc. Typically, microvascular anastomosis is a critical surgical point determining flap success. By providing the ability to monitor blood flow at the anastomosis site, the vascular monitoring loop disclosed herein allows for early detection of low or insufficient blood flow within the flap tissue, enabling medical practitioners (e.g., surgeons) to take corrective action before necrosis occurs and the free flap becomes unusable.

[0077] This vascular monitoring collar can be used in conjunction with flow monitoring systems that include multi-component probe systems, such as those described in PCT / US2018 / 061191 (“Vascular Monitoring Systems, Apparatus and Methods”), the disclosure of which is incorporated herein by reference.

[0078] like Figure 1 As shown, the probe assembly 100 may include a probe connector 110 for connection to a probe monitoring system. The probe assembly 100 may also include a suture sleeve 120 configured for attachment (e.g., via sutures) to a patient's body or clothing. The suture sleeve 120 may be made of medical-grade materials suitable for contact with human skin, such as USPV or VI grade materials. Various alternative devices can be used to attach the probe assembly 100 or the lead to the skin, including patches and adhesive pads. The suture sleeve 120, adhesive pad, or alternative device may be attached to the skin such that the force required to remove the pad or alternative device from the skin must be greater than the force required to remove the probe.

[0079] The probe cable 130 extends from the probe connector 110. At one end of the probe cable 130 is an end-of-probe component 140, such as a collar (see [link]). Figures 2 to 8B The Doppler probe or transducer is coupled (e.g., press-fitted) to the collar. In one example, the "probe end" component 140 may include a transducer removably coupled to a separate collar. In another example, the "probe end" component 140 may be a collar and transducer assembly (see [link to other examples]). Figures 2 to 8B ).

[0080] Figure 2An example "probe end" component 140a is shown. As Figure 2 shown, the collar 200 can include eyelets 210a and 210b that provide a clinician with a gripping surface and also allow the collar 200 to anchor to adjacent tissue, such as Figure 3B and Figure 3C further shown. The collar 200 also includes a probe holder 220 that is configured to receive a Doppler probe or transducer 230. In one example, the Doppler probe or transducer 230 can be press-fit into the probe holder 220. The probe holder 220 can include a receptacle that is configured to removably hold the Doppler probe or transducer 230 at a predetermined distance and at a predetermined angle relative to a longitudinal axis of the collar 200. The receptacle of the probe holder 220 can have an octagonal or hexagonal profile. For example, the octagonal or hexagonal profile can provide a plurality of surfaces for frictional engagement with the Doppler probe or transducer 230. In one example, the angle of the Doppler probe or transducer can be approximately 30 degrees from a flat end face of the collar 200, and thus 120 degrees from the longitudinal axis of the collar 200. In another example, the angle can be between 30 degrees and 60 degrees from the flat end face of the collar 200, and thus between 120 degrees and 150 degrees from the longitudinal axis of the collar 200.

[0081] As Figure 2 shown, the collar 200 has an inner diameter (D C ) 240 and a collar width (W C ) 250. The size and shape (e.g., annular) of the collar 200 can be designed such that the collar fits over a similarly sized blood vessel (e.g., an artery or vein). For example, the collar 200 can have an inner diameter (D C ) 240 between 1.0 mm and 4.0 mm. The collar width (W C ) 250 can be between 2.5 mm and 5.0 mm to provide stability over the blood vessel.

[0082] The collar 200 can be made of silicone, such as implant grade liquid silicone rubber ("LSR") or high consistency silicone rubber ("HCR"). The silicone can have a hardness (e.g., Shore A) between 40 and 80 and a tear strength between 240 ppi and 350 ppi. The silicone described above allows the collar 200 to conform to the surface of the blood vessel. In other examples, the collar 200 can be made of high density polyethylene ("HDPE"). Alternatively, the collar 200 can be made of Nusil 4750, Nusil 4840, thermoplastic, etc. The collar 200 can be made of other flexible or pliable materials. In one example, the collar 200 is permanently implanted into the patient. Additionally, the collar can also be bioabsorbable.

[0083] As shown in Figure 3A , Figure 3B and Figure 3C , the collar 200 is sized and shaped (e.g., annular) to fit over a similarly sized blood vessel (e.g., an artery or vein). As noted above, the collar can have an inner diameter (D C ) 240 of between 1.0 mm and 4.0 mm. In one example, the inner diameter (D C ) 240 of the collar 200 can be provided in size increments of 0.5 mm. It will be appreciated that the size and shape of the collar 200 can be designed to accommodate blood vessels (e.g., veins and arteries) commonly encountered in microsurgical and revascularization procedures, and to be useful for end-to-end anastomosis of such veins and arteries in the peripheral vasculature. For example, Figure 3A and Figure 3B show the collar 200 positioned over and advanced along a blood vessel 300 prior to anastomosis. The collar 200 can be positioned proximate to the anastomosis site such that the collar 200 is at, upstream of, or downstream of the anastomosis site. After the collar 200 is positioned at its desired location along the blood vessel 300, the collar 200 can be anchored to adjacent tissue by suturing the eyelets 210a and 210b to the adjacent tissue. Suturing the eyelets 210a and 210b to the adjacent tissue can advantageously remove strain relief for the Doppler probe 230 movement, as shown in Figure 3C . Figure 3B and Figure 3C show sutures 305 as a means of attaching the collar 200, more specifically the eyelets 210a and 210b, to adjacent tissue. It will be appreciated that other attachment means, such as staples, clips, etc., can be used.

[0084] Figure 4A and Figure 4B show another example “probe end” component 140a and an example collar 200. Figure 4A shows the collar 200 in an open configuration, while Figure 4B shows the collar 200 in a closed configuration. Similar to the collar 200 shown in Figure 2 , Figure 4A and Figure 4B , the collar 200 can include eyelets 210a and 210b that provide a clinician with a gripping surface and also allow the collar 200 to be anchored to adjacent tissue. For example, a clinician can grip the eyelets 210a and / or 210b with forceps, pincers, or other medical tools while positioning the collar 200. After the collar 200 is in place, the clinician can squeeze the eyelets 210a, 210b together to close the collar 200, and suture the two eyelets 210a, 210b together to maintain the collar 200 in the closed configuration (seeFigure 5B After the collar 200 is closed around the blood vessel, the clinician can suture the eyelets 210a and / or 210b to nearby tissue. The collar 200 also includes a probe holder 220 configured to receive a Doppler probe or transducer 230. In one example, the Doppler probe or transducer 230 may be press-fitted into the probe holder 220. The probe holder 220 may include a removable housing configured to hold the Doppler probe or transducer 230 removably at a predetermined distance and angle relative to the longitudinal axis of the collar 200 when the collar 200 is in the closed configuration. In one example, when the collar 200 is in the closed configuration, the angle of the Doppler probe or transducer 230 may be approximately 30 degrees to the flat end face of the collar 200, and therefore 150 degrees to the longitudinal axis of the collar 200. In another example, the angle can be between 30 and 60 degrees with the flat end face of the collar 200, and thus between 120 and 150 degrees with the longitudinal axis of the collar 200.

[0085] The collar 200 can be made of a flexible or tough material, allowing it to switch between an open and closed configuration. In one example, the collar 200 is permanently implanted in the patient. Alternatively, the collar 200 can also be bioabsorbable. For example, Figure 4A , Figure 4B , Figure 5A , Figure 5B and Figure 5C The collar 200 shown can have the same as Figure 2 , Figure 3A , Figure 3B and Figure 3C The collar 200 shown has the same material properties.

[0086] like Figure 4A As shown, the loop 200 is initially in an open configuration and can be positioned along the vessel even if it has not yet been cut or incised for anastomosis. For example, the loop 200 can be positioned along an uncut vessel to monitor blood flow through it. Figure 4A and Figure 4B The collar 200 shown can also be advanced along the blood vessel before or after the anastomosis is completed, which advantageously provides flexibility during the surgical procedure. Similar to... Figure 2 , Figure 3A , Figure 3B and Figure 3C The collar 200 shown is... Figure 4A and Figure 4B The collar 200 can be located near the anastomosis site, such that the collar is located at the anastomosis site, upstream of the anastomosis site, or downstream of the anastomosis site.

[0087] Figure 5A 、 Figure 5B and Figure 5C shows the collar 200 positioned on a blood vessel 300. The collar 200 can be sized and shaped (e.g., clip-shaped) such that it fits over a similarly sized blood vessel 300 (e.g., an artery or a vein). For example, the collar 200 can have an inner diameter (D Figure 2 ) 240 similar to the inner diameter of the collar 200 of C ) 240 between 1.0 mm and 4.0 mm. In one example, the inner diameter (D C ) 240 of the collar 200 can be provided in 0.5 mm increments in the closed position. It should be appreciated that the collar 200 can be sized and shaped to accommodate blood vessels (e.g., veins and arteries) commonly encountered in microsurgical and revascularization procedures and suitable for end-to-end anastomosis of these veins and arteries in the peripheral vascular system. After the collar 200 is positioned at its desired location along the blood vessel 300, the collar 200 can be closed by suturing the eyelets 210a, 210b together such that the collar 200 remains in the closed configuration. The collar 200 can also be anchored to adjacent tissue by suturing the eyelets 210a and / or 210b to the adjacent tissue. Suturing the eyelets 210a and 210b to the adjacent tissue can advantageously provide strain relief for removal of the Doppler probe 230 as shown in Figure 5C . Figure 5B and Figure 5C shows suture 305 as a means for maintaining the collar 200 in the closed configuration. It should be appreciated that other attachment means, such as pins, clips, etc., can be used to maintain the collar 200 in the closed configuration.

[0088] Figure 6 shows another embodiment of a collar or band 600a. For example, as shown in Figure 6 , the band 600a can include eyelets 610 that provide a gripping surface for the clinician and also allow the collar or band 600a to be anchored to adjacent tissue. The collar or band 400 also includes a probe holder 220 configured to receive a Doppler probe or transducer 230. Similar to the embodiment described in Figures 2 to 5C , the Doppler probe or transducer 230 can be press-fit into the probe holder 220. As described above, the probe holder 220 can include a receptacle 620 configured to removably hold the Doppler probe or transducer 230 at a predetermined distance and at a predetermined angle relative to the longitudinal axis of the collar or band 600a when the band 600a is closed around a blood vessel. The receptacle 620 of the probe holder 220 can be sized and shaped similar to Figures 2 to 5Cprobe holder 220 can have an octagonal or hexagonal profile that provides multiple surfaces for frictional engagement with the Doppler probe or transducer 230. In one example, when the cuff 600a is closed around a blood vessel, the angle of the Doppler probe or transducer 230 can be at an angle of about 30 to 60 degrees to the flat end face of the cuff or strap 600a, and thereby at an angle of 120 to 150 degrees to the longitudinal axis of the cuff formed by the cuff 600a.

[0089] The cuff or strap 600a can be made of high density polyethylene ("HDPE"). In one example, the strap 600a can be made of silicone, such as implant grade liquid silicone rubber ("LSR") or high consistency silicone rubber ("HCR"). The silicone can have a hardness (e.g., Shore A) of between 40 and 80, and a tear strength of between 240 ppi and 350 ppi. The silicone described above allows the cuff or strap to conform to the surface of a blood vessel while providing a strong material that can withstand the stresses associated with closing the cuff 600a around a blood vessel. In other examples, the strap 600a can be made of Nusil 4750, Nusil 4840, thermoplastic, etc. The strap 600a can be made of other flexible or pliable materials such that the strap 600a is suitable for wrapping around a blood vessel of a patient. In one example, the strap 600a is permanently implanted in a patient and can be bioabsorbable.

[0090] Once the strap 600a is wrapped around a blood vessel of a patient and maintained in its closed position, the strap 600a can resemble a closed cuff. The strap 600a has a strap width (W S ) 650 and a strap length (L S ) 660. The strap width (W S ) can be between 2.5 mm and 5.0 mm to provide stability on the blood vessel. The strap length (L S ) 660 can be long enough such that the strap 600a can be wrapped around a blood vessel and also have enough length to be closed (see Figure 8A and Figure 8BFor example, the size and shape of the bandage 600a can be designed such that, when closed, the bandage 600a forms a loop that fits over a vessel of similar size (e.g., an artery or vein). For example, the loop formed by the closure bandage 600a can have an inner diameter between 1.0 mm and 4.0 mm. In one example, the bandage 600a can be provided in increments of approximately 1.5 mm to accommodate different vessel sizes (e.g., vessel sizes differentiated in increments of approximately 0.5 mm). It should be understood that the size and shape of the bandage 600a can be designed to accommodate vessels (e.g., veins and arteries) commonly encountered in microsurgery and vascular reconstruction procedures, and is suitable for end-to-end anastomoses of these veins and arteries in the peripheral vascular system.

[0091] Figure 7A , Figure 7B and Figure 7C Another example embodiment of the strap 600b is shown. The strap 600b may include a base 710, a saddle 720, and a band 730. A probe holder 220 may be formed as part of the base 710, which provides stability to the strap 600b and also provides a gripping surface for clinicians when manipulating and positioning the strap 600b. The saddle 720 has a proximal end 722 and two corresponding distal ends 724a, 724b. The saddle 720 may extend from the base 710 at the proximal end 722 of the saddle. The corresponding band 730 extends from the saddle 720 at each end. For example, each corresponding band 730 may extend from the corresponding distal end 724a, 724b of the saddle 720.

[0092] The saddle 720 and the corresponding strap 730 may meet at a joint 725 (e.g., the corresponding distal ends 724a, 724b of the saddle 720). When the strap 600b is extended to the most open configuration, the first end of the strap 600b will be the strap 730, followed by the first portion of the saddle 720 and the base 710, and then the strap 600b will continue to the second portion of the saddle 730 and another corresponding strap 730.

[0093] In one example, the saddle portion 720 extends outward from the base 710 and forms a contact surface 740 for a portion of the blood vessel. The contact surface 740 may be shaped like an inverted or upside-down saddle that creates a bowl-shaped or basin-shaped surface. For example, the saddle portion 720 may be flexible while maintaining sufficient rigidity to create the pre-formed contact surface 740. Alternatively, the saddle portion 720 and the strap portion 730 may be flexible and resilient enough that when the contact surface 740 is adjacent to a horizontal surface, the strap 600b will lie flat on that horizontal surface.

[0094] like Figure 7B and Figure 7C As shown, the base 710 has a height (H) BASE)750 and a width (W BASE )760. The height (H BASE )750 can be approximately 2.25 mm, and the width (W BASE )760 can be between 2.5 mm and 5.0 mm. A wider base 710 can be implemented to provide additional stability over a blood vessel.

[0095] Additionally, the saddle 720 has a height (H S )752, which can be approximately 2.65 mm. The distance 764 between each end of the saddle 720 (e.g., at the joint 725) can be approximately 4.0 mm. The strap portion 730 has a height (H BAND )754, which can be approximately 6.0 mm. When the band 600b is in a relaxed position (as shown in Figure 7B ), especially with the saddle 720 maintaining its shape, the distance 766 between the ends of the strap portion 730 can be approximately 5.0 mm.

[0096] The strap portion can have a wall thickness (T BAND )770 of between approximately 0.1 mm and approximately 0.3 mm. The wall thickness (T BAND )770 can be selected and configured based on the closure mechanism of the band 600b. For example, different closure clips can be compatible with different wall thicknesses. Additionally, the wall thickness (T BAND )770 can be selected to increase or decrease the flexibility, rigidity, and / or durability of the band 600b. The band 600b can have a width (W STRAP )762 of approximately 2.5 mm to 5.0 mm at the ends of the strap portion 730. Similar to the wall thickness (T BAND )770, the width (W STRAP )762 can be selected to increase or decrease the flexibility, rigidity, and / or durability of the band 600b. Additionally, the width (W STRAP )762 can be selected and configured based on the closure mechanism of the band 600b. For example, different closure clips can be compatible with different band widths.

[0097] The dimensions of the saddle 720 and the strap portion 730 can be adjusted for different blood vessel sizes. For example, the strap portion can have sufficient height to provide sufficient closure surface after the band 600b is closed around a blood vessel having a vessel diameter of between 1.0 mm and 4.0 mm. It should be appreciated that the dimensions and shape of the band 600ab can be designed to accommodate blood vessels (e.g., veins and arteries) typically encountered in microsurgical and revascularization procedures, and to be suitable for end-to-end anastomosis of such veins and arteries in the peripheral vascular system.

[0098] As shown in Figure 7C ,Figure 7C is a cross-sectional view taken about line 7C-7C of FIG. B, the receptacle 620 of the probe holder 220 can have a conical profile with a cylindrical transition region 780. The diameter of the cylindrical transition region 780 can be between 0.015 inches and 0.030 inches (e.g., 0.38 mm and 0.76 mm). The cylindrical transition region 780 with a smaller diameter can provide a tighter grip or squeeze on the corresponding Doppler probe or transducer 230. The probe holder 220 can be oriented at an angle 782 between 120 degrees and 150 degrees from the longitudinal axis of the collar formed by the closure band 600b.

[0099] Figure 8A and Figure 8B An example is shown of positioning a band such as the band 600a or the band 600b around a blood vessel 300. The band 600a and the band 600b can be collectively referred to as the band 600 hereinafter. Figure 8A and 8B The band 600 shown in Figure 6 may include every feature of the band 600a described in Figure 8B , every feature of the band 600b, or a combination thereof. As shown in Figure 8A , the band assembly 800 can include a clamp 810, a clasp, a strap, or other closure mechanism that maintains the band 600 in a closed configuration around the blood vessel 300 such that the band 600 forms a collar around the blood vessel 300. For example, Figure 8B , the band 600 is wrapped around the blood vessel 300 to form a collar. The collar formed by the band 600 can be located proximate to the anastomosis site such that the collar is at the anastomosis site, upstream of the anastomosis site, or downstream of the anastomosis site. After the band 600 is wrapped around the blood vessel 300 and maintained in its closed orientation (e.g., such that the band 600 forms a collar) and is in its desired location along the blood vessel 300, the collar formed by the band 600 can be anchored to adjacent tissue by suturing the eyelet (see Figure 6 ) to the adjacent tissue. Similar to the embodiments described in Figure 3C and Figure 5C , suturing the eyelet to the adjacent tissue can advantageously provide strain relief for removal of the Doppler probe.

[0100] Figure 9A and Figure 9B shows another example embodiment of the band 600c having a conical profile with a cylindrical transition region 780. The diameter of the cylindrical transition region 780 can be between 0.015 inches and 0.030 inches (e.g., 0.38 mm and 0.76 mm). The cylindrical transition region 780 with a smaller diameter can provide a tighter grip or squeeze on the corresponding Doppler probe or transducer 230. The probe holder 220 can be oriented at an angle 782 between 120 degrees and 150 degrees from the longitudinal axis of the collar formed by the closure band 600b. Figure 8BThe illustrated clamps, buckles, or straps have different closure mechanisms. For example, strap 600c can include a plurality of sized holes 910 spaced along strap 600c and adapted to maintain the strap in a closed configuration when fitted over closure prongs 920. For example, sized holes 910 can be sized and shaped such that they can be press fit over closure prongs 920. Sized holes 910 can be spaced along strap 600c with a spacing of approximately 1.5 mm between each hole to accommodate different vessel sizes (e.g., vessel sizes differentiated by approximately 0.5 mm increments). The spacing between each sized hole 910 can instead be 1.0 mm or some other spacing to accommodate different spacing of vessel sizes.

[0101] As described above, the straps 600a, 600b, and 600c described herein can be sized and shaped for particular vessel sizes such that one strap is configured for vessels between 1.0 mm and 2.0 mm, another strap is configured for vessels between 2.0 mm and 3.0 mm, and a different strap is configured for vessels between 3.0 mm and 4.0 mm. In the presence of different strap sizes or lengths adapted for different vessel sizes, sized holes 910 can be positioned at a tighter spacing such that the strap can be adjusted in 0.2 mm increments to fit a vessel with a diameter between 1.0 mm and 2.0 mm (e.g., sized holes 910 can be configured such that the strap can be adjusted to form a cuff with an inner diameter of 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, and 2.0 mm). It should be appreciated that the straps 600c can be sized and shaped and sized holes 910 can be positioned to accommodate vessels (e.g., veins and arteries) commonly encountered in microsurgical and revascularization procedures and adapted for end-to-end anastomosis of these veins and arteries in the peripheral vascular system.

[0102] The prong 920 can include a flange or lip configured to maintain the strap 600c in the closed configuration. For example, the sized hole 910 can be positioned over and press fit over the prong 920 such that the prong 920 is pushed through the sized hole 910. The material of the strap can allow the sized hole to expand and flex to fit over the flange or lip of the prong 920 before relaxing back to its original shape. After the prong 920 is pushed through the sized hole 910, the flange or lip is adapted to prevent the strap 600c from unwinding to an open position. For example, the size and shape of the flange or lip can be designed such that the force associated with the tendency of the strap to relax back to its open position is insufficient to cause the sized hole 910 to expand and flex to refit over the flange or lip of the prong 920. The material of the strap 600c and the geometry of the sized hole 910 and prong are configured such that a clinician can manipulate the strap 600c between the open and closed configurations while also preventing the strap 600c from opening without clinician intervention.

[0103] Similar to the strap shown in Figure 8A and Figure 8B the strap shown in Figure 9A and Figure 9B may include each of the features of the strap described in Figure 6 or Figures 7A-7C Additionally, Figure 6 , Figures 7A-7C , Figure 8A , Figure 8B , Figure 9A and Figure 9B the strap shown in Figure 2 , Figure 3A , Figure 3B , Figure 3C , Figure 4B , Figure 5B and Figure 5C may be configured and arranged such that when in the closed configuration, the strap forms a loop that is oriented similarly to the loop shown in For example, the probe holder can include a receptacle configured to removably hold the Doppler probe or transducer at a predetermined distance and at a predetermined angle relative to a longitudinal axis of the loop formed by the strap when the strap is in the closed configuration (e.g., the angle of the Doppler probe or transducer can be about 30 degrees from the flat end face of the loop, thereby 120 degrees from the longitudinal axis of the loop formed by the strap when the strap is in the closed configuration). In another example, the angle can be between 30 and 60 degrees from the flat end face of the strap 600, thus between 120 and 150 degrees from the longitudinal axis of the loop formed by the closed strap 600.

[0104] A sensing device, such as a Doppler probe or transducer, inserted into the collar enables a medical practitioner (e.g., a surgeon) to monitor and analyze blood flow and / or blood flow velocity to determine surgical success and / or confirm vessel patency.

[0105] Any transducer suitable for use in ultrasonic Doppler monitoring can be used with the collar. In one example embodiment, the Doppler probe or transducer is made of an approved implantable material, such as HDPE or silicone. In another example, the transducer 230 includes a piezoelectric crystal. The transducer 230 can be any size to accommodate the size of a corresponding probe holder for use on the collar. For example, a circular transducer 230 is suitable for being received by a receptacle that is circular in shape on the inner surface. In another example, the receptacle 620 formed by the probe holder can be octagonal or hexagonal (see Figure 3A ), to provide a tighter friction fit with the end of the Doppler probe or transducer. The transducer 230 can be a circular piezoelectric crystal with a size between about 0.5 mm and about 1 mm. In one example, the Doppler probe or transducer 230 includes an end with a circular piezoelectric crystal with a size between about 0.5 mm and about 1 mm, a Teflon-coated coaxial wire, and a metal connector.

[0106] A Doppler probe coupled with the collar or band disclosed herein can be suitable for detecting blood flow at an anastomosis site and confirming vessel patency at the anastomosis site during and after surgery. For example, blood flow can be detected for up to about 14 days after surgery.

[0107] Many of the features and advantages of the present disclosure can be apparent from the written description and it is intended that the appended claims be construed to cover all such features and advantages of the present disclosure. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the present disclosure to the exact construction and operation described and shown herein. Accordingly, all suitable modifications and equivalents can be resorted to as falling within the scope of the present disclosure, whether now or in the future predicable. The embodiments described are to be considered merely illustrative of the principles of the disclosure and the present disclosure is not to be limited to the specific constructions and methods described herein, but rather is to be accorded the full scope of the language of the following claims, and equivalents thereof.

Claims

1. A vascular monitoring system, comprising: A collar, the collar being configured to be positioned around the patient's blood vessels; and A transducer is coupled to the collar and is configured to emit ultrasound signals transmitted through the patient's blood vessels.

2. The vascular monitoring system of claim 1, wherein the collar includes at least one eyelet adapted to be sutured to adjacent tissue to securely position the collar around the patient's blood vessels.

3. The vascular monitoring system according to any one of claims 1 or 2, wherein the collar includes a probe holder, the probe holder being sized and shaped to receive the transducer.

4. The vascular monitoring system according to claim 3, wherein the transducer is coupled to the collar by frictional engagement with the probe holder.

5. The vascular monitoring system according to any one of claims 1 to 4, wherein the collar is made of at least one of implantable liquid silicone rubber (LSR) and high-consistency silicone rubber (HCR) having a hardness between 40 and 80.

6. The vascular monitoring system according to any one of claims 1 to 5, wherein the collar is configured to be positioned around the anastomosis site of the patient's blood vessels.

7. The vascular monitoring system according to any one of claims 1 to 5, wherein the collar is configured to be located at one of an upstream of the anastomosis site of the patient's blood vessel and a downstream of the anastomosis site of the patient's blood vessel.

8. The vascular monitoring system according to any one of claims 1 to 7, wherein the transducer is removably coupled to the collar.

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