An intraoperative ultrasound navigation probe for transnasal skull base surgery

Abstract

The application provides an intraoperative ultrasonic navigation probe for transnasal skull base surgery, which comprises a micro ultrasonic transducer, an elongated probe rod, a coaxial cable and a connector; the micro ultrasonic transducer is installed at the front end of the elongated probe rod, the coaxial cable passes through the hollow of the elongated probe rod, and the two ends of the coaxial cable are connected with the micro ultrasonic transducer and the connector respectively; the ultrasonic transducer is integrated at the front end of the elongated probe rod with an outer diameter of less than or equal to 7.5 mm, which can smoothly pass through the single nostril to reach the skull base surgery area, and overcomes the limitation that the conventional ultrasonic probe cannot be used for transnasal surgery due to the bulky appearance; under the constraint of the small probe diameter, the high-frequency working frequency of 20MHz-30MHz is matched. The application provides a perspective imaging tool for neurosurgeons according to the observation requirements of the depth of skull base lesions and fine anatomical structures, which assists the surgeons in accurately determining the tumor boundary, tracking the position of important blood vessels and evaluating the degree of resection; and the application has important clinical significance for further improving the safety and thoroughness of transnasal skull base surgery.

Description

Technical Field

[0001] This invention belongs to the field of ultrasound imaging equipment technology, specifically an intraoperative ultrasound navigation probe for transnasal skull base surgery. Background Technology

[0002] Transnasal skull base surgery is a modern neurosurgical technique that utilizes the nasal cavity, a natural anatomical passage, to perform minimally invasive resection of lesions in the skull base region, such as pituitary gland tumors, craniopharyngiomas, and chordomas. This procedure avoids the extensive bone flap removal and brain tissue exposure associated with traditional craniotomy, offering significant advantages such as no visible scars, rapid postoperative recovery, and minimal traction damage to brain tissue. It has become an important direction in the treatment of skull base lesions.

[0003] Transnasal skull base surgery faces significant technical challenges. The surgical path is narrow, the field of vision is limited, and the lesion is surrounded by important neurovascular structures such as the internal carotid artery, cavernous sinus, optic nerve, and cranial nerves. The success of the surgery heavily depends on the surgeon's accurate identification of deep anatomical structures and real-time assessment of the lesion's boundaries. Currently, the navigation technologies routinely used in clinical practice are mostly based on preoperative CT or MRI images. These static images cannot reflect tissue displacement and deformation caused by instrument manipulation, cerebrospinal fluid loss, and tumor resection during surgery, resulting in errors of several millimeters or even more between the images and the actual situation. This precision gap significantly increases the risk of accidental injury to blood vessels or residual tumor when performing delicate operations in the extremely limited space of the skull base region. Therefore, the need for real-time, high-resolution imaging of tumor boundaries, residual tumor, and vascular course during surgery is extremely urgent.

[0004] Intraoperative real-time imaging technology is a key direction for solving the above problems. Currently, clinical practice mainly relies on neuroendoscopy to provide high-resolution optical images of the surgical field surface. However, endoscopic imaging is limited to the tissue surface and cannot provide crucial information such as deep tumor boundaries, capsule integrity, and the course of blood vessels covered by soft tissue or located deep within the bone window.

[0005] Ultrasound imaging, as a real-time, radiation-free intraoperative imaging tool, has been used in some neurosurgical procedures. However, existing laparoscopic or conventional neurosurgical ultrasound probes are limited by their size, scanning frequency, and design structure, making it difficult to pass smoothly through the narrow nasal passage (usually only 1-2 cm in diameter) and closely follow the skull base bone defect area for multi-angle scanning.

[0006] Therefore, developing an intraoperative ultrasound navigation device specifically designed for transnasal skull base surgery, capable of real-time image updates of the lesion and surrounding key structures during resection, and assisting doctors in accurately determining tumor boundaries, tracking the location of important blood vessels, and assessing the extent of resection, is of significant clinical importance for overcoming existing technological bottlenecks and further improving the safety and thoroughness of transnasal skull base surgery. Summary of the Invention

[0007] The purpose of this invention is to solve the problem that conventional ultrasound probes, limited by their size, scanning frequency and design structure, cannot easily pass through the narrow nasal passage and closely follow the skull base bone defect area for multi-angle scanning.

[0008] To achieve the above objectives, the first aspect of this invention provides an intraoperative ultrasound navigation probe for transnasal skull base surgery, comprising a miniature ultrasound transducer, a slender probe, a coaxial cable, and a connector. The miniature ultrasound transducer is mounted on the front end of the slender probe, and the coaxial cable passes through the hollow portion of the slender probe, with both ends of the coaxial cable connected to the miniature ultrasound transducer and the connector, respectively. Through miniaturization, the slender probe and the miniature ultrasound transducer can smoothly extend through a single nasal inlet to the skull base lesion area (surgical area), overcoming the limitation of conventional ultrasound probes being too bulky for transnasal surgery. The connector is used to connect to the ultrasound host.

[0009] Preferably, the maximum outer diameter of the slender probe is no greater than 7.5 mm, and the maximum dimension of the miniature ultrasonic transducer in the direction perpendicular to the axis of the slender probe is no greater than 7.5 mm.

[0010] Preferably, one side of the miniature ultrasonic transducer has an outwardly convex arc surface structure.

[0011] Preferably, the miniature ultrasonic transducer includes an acoustic lens, ultrasonic elements, and an acoustic absorption layer. Multiple ultrasonic elements and the acoustic absorption layer are installed inside the acoustic lens. The acoustic lens is mechanically connected to a slender probe. One end of each ultrasonic element, equipped with a piezoelectric vibrator, contacts the inner wall of the acoustic lens, and the other end of the ultrasonic element is connected to the acoustic absorption layer.

[0012] Among them, the acoustic lens uses the principle of sound wave refraction to converge diverging sound waves into a sharp sound beam, thereby improving the lateral resolution and quality of the ultrasound image; the ultrasonic array element converts the pulse electrical signal into an ultrasonic vibration signal and converts the received ultrasonic reflected echo signal into an electrical signal; the acoustic absorption layer absorbs the sound wave energy radiated backward by the ultrasonic array, suppresses the mechanical ringing effect and internal acoustic reverberation, and significantly shortens the spatial pulse length, thereby ensuring the probe's sub-millimeter axial resolution.

[0013] Preferably, the surface of the acoustic lens on which the ultrasonic array elements are mounted is an outwardly convex arc-shaped structure. Multiple ultrasonic array elements are arranged in an arc shape inside the acoustic lens. Utilizing the structural characteristic of the ultrasonic array elements being arranged in a convex arc shape, the system controls the transmission and reception timing of each array element to form a wide-angle fan-shaped scanning sound field.

[0014] Preferably, the number of ultrasonic array elements is 48-96.

[0015] Preferably, the center frequency of the miniature ultrasonic transducer is 20MHz-30MHz, which, under the constraint of the extremely small probe outer diameter, matches a high-frequency operating frequency of 20MHz-30MHz. This achieves synergistic optimization of penetration depth and image resolution to meet the observation needs of skull base lesion depth and fine anatomical structures.

[0016] Based on the aforementioned ultrasound navigation probe, a second aspect of the present invention proposes a method for real-time intraoperative image acquisition, comprising the following steps:

[0017] S1: Use a thin probe to insert the miniature ultrasonic transducer through the nostril until the miniature ultrasonic transducer reaches the skull base bone defect area or the dura mater surface.

[0018] S2: Input a high-frequency excitation electrical pulse into the miniature ultrasonic transducer to cause the miniature ultrasonic transducer to generate ultrasonic vibration, and emit ultrasonic waves to the lesion tissue through the acoustic lens.

[0019] S3: Controls the transmission and reception timing of multiple ultrasonic array elements on the miniature ultrasonic transducer to form a wide-angle fan-shaped scanning sound field.

[0020] S4: Controls a miniature ultrasonic transducer to convert ultrasonic reflected echoes into electrical signals, which are then processed to reconstruct a two-dimensional grayscale image in real time.

[0021] Preferably, in step S2, the center frequency of the ultrasonic vibration generated by the miniature ultrasonic transducer is 20MHz-30MHz.

[0022] Preferably, in step S4, the frequency shift signal generated by blood flow is converted into a color blood flow image and superimposed on a two-dimensional grayscale image. This provides real-time updated images during surgery, addressing the issue of brain drift causing inaccurate positioning in preoperative MRI navigation. Real-time identification of the internal carotid artery position using Doppler mode effectively avoids fatal large vessel damage due to tissue displacement, significantly improving surgical safety.

[0023] Beneficial effects:

[0024] Compared with the prior art, the present invention can achieve at least the following technical effects;

[0025] 1. This invention is specifically designed for transnasal surgery. Through miniaturization, it can smoothly reach the surgical area of ​​the skull base through one nostril, overcoming the limitation of conventional ultrasound probes that cannot be used in transnasal surgery due to their bulky shape. It provides neurosurgeons with a fluoroscopic imaging tool to help doctors accurately determine tumor boundaries, track the location of important blood vessels, and assess the extent of resection. It has important clinical significance for breaking through existing technical bottlenecks and further improving the safety and thoroughness of transnasal skull base surgery.

[0026] 2. The miniature ultrasonic transducer of the present invention adopts an arc-shaped structure, with multiple ultrasonic array elements arranged in an arc. By controlling the transmission and reception timing of each ultrasonic array element, a wide-angle fan-shaped scanning sound field is formed, thereby enabling the probe to obtain a wide field of view of deep lesions and surrounding structures even in the narrow contact space of the skull base.

[0027] 3. The structure of this invention is ergonomically designed, and the intuitive imaging helps young doctors quickly understand the complex three-dimensional anatomical relationships of the skull base, reducing the difficulty of surgery and shortening the training cycle.

[0028] 4. This invention addresses the problem of inaccurate positioning caused by brain drift in preoperative MRI navigation. This probe provides real-time updated images during surgery. By using Doppler mode to identify the location of the internal carotid artery in real time, it can effectively avoid fatal large blood vessel damage caused by tissue displacement, significantly improving surgical safety. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0030] Figure 2 This is a schematic diagram of the cross-sectional structure of the slender probe and micro transducer of the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of the miniature ultrasonic transducer of the present invention.

[0032] In the figure: 1. Miniature ultrasonic transducer; 101. Acoustic lens; 102. Ultrasonic array element; 103. Acoustic absorption layer; 2. Slender probe; 201. Insulating protective layer; 3. Coaxial cable; 4. Connector. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] Please see Figure 1-3 This invention first proposes an intraoperative ultrasound navigation probe for transnasal skull base surgery, such as... Figure 1 As shown, the device includes a miniature ultrasonic transducer 1, a slender probe 2, a coaxial cable 3, and a connector 4. The miniature ultrasonic transducer is mounted on the front end of the slender probe 2. The coaxial cable 3 passes through the hollow part of the slender probe 2, and its two ends are connected to the miniature ultrasonic transducer 1 and the connector 4, respectively. The miniature ultrasonic transducer 1 and the slender probe 2 can extend from the nasal inlet to the lesion area at the base of the skull. The connector 4 is used to connect to the ultrasound host.

[0035] like Figure 2As shown, the slender probe 2 is a hollow cylindrical structure with a length of 120-180mm. The miniature ultrasonic transducer 1 is welded to one end of the slender probe 2 or integrally formed with the slender probe 2. The coaxial cable 3 passes through the hollow part of the slender probe 2. An insulating protective layer 201 is provided between the coaxial cable 3 and the slender probe 2. The maximum outer diameter of the slender probe 2 does not exceed 7.5mm. The maximum size of the miniature ultrasonic transducer 1 in the direction perpendicular to the axis of the slender probe 2 also does not exceed 7.5mm, so as to adapt to the physiological curvature and narrow space of the adult nostrils and ensure that the probe can easily pass through the nasal cavity without damaging the nasal mucosa.

[0036] Specifically, such as Figure 3 As shown, the miniature ultrasonic transducer 1 includes an acoustic lens 101, ultrasonic elements 102, and an acoustic absorption layer 103. Multiple ultrasonic elements 102 and acoustic absorption layer 103 are installed inside the acoustic lens 101. The acoustic lens 101 is mechanically connected to the slender probe 2. One end of each ultrasonic element 102, which is equipped with a piezoelectric vibrator, is in contact with the inner wall of the acoustic lens 101, and the other end of the ultrasonic element 102 is connected to the acoustic absorption layer 103.

[0037] The acoustic lens 101 utilizes the principle of sound wave refraction to converge the divergent sound waves emitted by multiple ultrasonic array elements 102 into a sharp sound beam, thereby improving the lateral resolution and quality of the ultrasound image. The multiple ultrasonic array elements 102 utilize the piezoelectric effect of piezoelectric crystals to convert high-frequency pulse electrical signals into mechanical vibrations and emit ultrasonic signals to human tissue through the acoustic lens. At the same time, it receives ultrasonic signals reflected by human tissue and converts them into electrical signals. The acoustic absorption layer 103 absorbs the sound wave energy radiated backward by the ultrasonic array elements 102, suppressing the mechanical ringing effect and internal sound wave reverberation of the miniature ultrasonic transducer 1.

[0038] Furthermore, the side surface of the acoustic lens 101 on which the ultrasonic array element 102 is mounted is an outwardly convex arc-shaped surface structure, and the multiple ultrasonic array elements 102 are arranged in an arc shape inside the acoustic lens 101.

[0039] The number of ultrasonic array elements 102 is 48-96, and the center frequency of the miniature ultrasonic transducer 1 is 20MHz-30MHz. With an extremely small probe outer diameter, through high-frequency acoustic design, both small size and high imaging resolution are achieved, allowing it to be inserted and seen clearly.

[0040] The method for acquiring real-time intraoperative images using the intraoperative ultrasound navigation probe in the above-mentioned surgery is as follows:

[0041] Insertion and positioning: The doctor slowly inserts the slender probe 2 and the miniature ultrasonic transducer 1 of the ultrasonic navigation probe of this invention through the patient's nostril until the miniature ultrasonic transducer 1 reaches the skull base bone defect area or the dura mater surface.

[0042] Signal excitation and acoustic wave emission: After the ultrasonic host is started, the host generates a high-frequency excitation electrical pulse, which is transmitted losslessly to the ultrasonic array element 102 of the miniature ultrasonic transducer 1 via the coaxial cable 3. The ultrasonic array element 102 generates high-frequency mechanical vibration based on the inverse piezoelectric effect, thereby exciting high-frequency ultrasonic waves with a center frequency of 20MHz-30MHz and emitting them forward to the tissue through the acoustic lens 101.

[0043] Acoustic field scanning and wide field-of-view focusing: The ultrasound waves emitted by the ultrasound array element 102 pass through the acoustic lens 101, which physically focuses the sound beam, effectively narrowing the beam width to improve lateral resolution. Simultaneously, utilizing the convex arc-shaped arrangement of the ultrasound array elements 102, the system controls the transmission and reception timing of each element 102, forming a wide-angle fan-shaped scanning acoustic field. This allows the probe to acquire a broad field of view of deep lesions and surrounding structures even within the narrow contact space of the skull base.

[0044] Echo reception and noise reduction control: When ultrasound waves propagate within the skull base tissue, they encounter tissue interfaces with different acoustic impedance characteristics (such as tumor parenchyma and capsule, blood vessel wall and blood, brain parenchyma, etc.), generating reflected echoes of varying intensities. These echo signals return and act on the ultrasound array element 102, which converts the reflected echo signals into weak electrical signals based on the positive piezoelectric effect. During this process, the acoustic absorption layer 103 (backing material) located behind the ultrasound array element 102 absorbs the acoustic energy radiated rearward by the element, suppressing mechanical ringing effects and internal acoustic reverberation, significantly shortening the spatial pulse length, thereby ensuring the probe's sub-millimeter axial resolution.

[0045] Image reconstruction and anatomical identification: The weak electrical signal generated by the echo received by the ultrasound array element 102 is transmitted back to the ultrasound host via the coaxial cable 3 and connector 4. After processing such as beamforming, signal amplification, and envelope detection, it is reconstructed in real time into a high-resolution two-dimensional grayscale image (B mode), which intuitively reflects the differences in tissue echoes to delineate the tumor boundary.

[0046] When switched to Doppler mode, the system further processes the frequency shift signal generated by blood flow and converts it into a color blood flow image overlay display, thereby accurately identifying the course of important hidden blood vessels around the lesion in real time, assisting doctors in judging the extent of resection and avoiding accidental damage to blood vessels.

[0047] In summary, this invention proposes a miniaturized high-frequency ultrasound probe structure specifically designed for transnasal skull base surgery. The ultrasound transducer is integrated into the tip of a slender probe with an outer diameter ≤ 7.5mm, overcoming the physical limitations of conventional ultrasound probes that cannot pass through the natural nasal cavity due to their excessive size. Under the constraint of an extremely small probe outer diameter, a high-frequency operating frequency of 20MHz-30MHz is achieved. This optimizes penetration depth and image resolution to meet the observation needs of skull base lesion depth and fine anatomical structures. It fills the gap in dedicated transnasal equipment, achieving a leap from static navigation to dynamic correction, significantly improving surgical safety, enhancing surgical smoothness, and shortening the learning curve.

[0048] In the description of this invention, the term "a plurality of" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In the description of this invention, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An intraoperative ultrasound navigation probe for transnasal skull base surgery, characterized in that, It includes a miniature ultrasonic transducer (1), a slender probe (2), a coaxial cable (3), and a connector (4); the miniature ultrasonic transducer is installed at the front end of the slender probe (2), the coaxial cable (3) passes through the hollow part of the slender probe (2), and the two ends of the coaxial cable (3) are respectively connected to the miniature ultrasonic transducer (1) and the connector (4). The miniature ultrasonic transducer (1) and the slender probe (2) can be inserted from the nasal entrance and extended to the lesion area at the base of the skull.

2. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 1, characterized in that, The maximum outer diameter of the slender probe (2) is no greater than 7.5 mm, and the maximum dimension of the micro ultrasonic transducer (1) in the direction perpendicular to the axis of the slender probe (2) is no greater than 7.5 mm.

3. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 1, characterized in that, One side of the micro ultrasonic transducer (1) is an outwardly convex arc structure.

4. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 1, characterized in that, The miniature ultrasonic transducer (1) includes an acoustic lens (101), an ultrasonic array element (102), and an acoustic absorption layer (103). Multiple ultrasonic array elements (102) and acoustic absorption layer (103) are installed inside the acoustic lens (101). The acoustic lens (101) is mechanically connected to a slender probe (2). One end of each ultrasonic array element (102) equipped with a piezoelectric vibrator is in contact with the inner wall of the acoustic lens (101), and the other end of the ultrasonic array element (102) is connected to the acoustic absorption layer (103).

5. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 4, characterized in that, The acoustic lens (101) has an outwardly convex arc-shaped surface structure on one side where the ultrasonic array elements (102) are installed, and multiple ultrasonic array elements (102) are arranged in an arc shape inside the acoustic lens (101).

6. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 4, characterized in that, The number of ultrasonic array elements (102) is 48-96.

7. The intraoperative ultrasound navigation probe for transnasal skull base surgery according to claim 1, characterized in that, The center frequency of the micro ultrasonic transducer (1) is 20MHz-30MHz.

8. A method for intraoperative real-time image acquisition based on the ultrasound navigation probe according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Using a slender probe (2), insert the miniature ultrasonic transducer (1) through the nostril until the miniature ultrasonic transducer (1) reaches the skull base bone defect area or the dura mater surface. S2: Input a high-frequency excitation pulse into the micro ultrasonic transducer (1) to generate ultrasonic vibration, and emit ultrasonic waves to the lesion tissue through the acoustic lens (101). S3: Control the transmission and reception timing of multiple ultrasonic array elements (102) on the micro ultrasonic transducer (1) to form a wide-angle fan-shaped scanning sound field. S4: Control the micro ultrasonic transducer (1) to convert the ultrasonic reflected echo into an electrical signal, and reconstruct a two-dimensional grayscale image in real time after signal processing.

9. The method for acquiring real-time intraoperative images according to claim 8, characterized in that, In step S2, the micro ultrasonic transducer (1) generates ultrasonic vibrations with a center frequency of 20MHz-30MHz.

10. The method for acquiring real-time intraoperative images according to claim 8, characterized in that, In step S4, the frequency shift signal generated by blood flow is converted into a color blood flow image and superimposed on a two-dimensional grayscale image.

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