A scalpel for harvesting connective tissue grafts from the palatal side of the maxilla in layers

Abstract

The application discloses a surgical knife for layered cutting of connective tissue grafts on the palate side of the maxilla, and belongs to the technical field of oral medical instruments. The surgical knife comprises a handle, a connecting rod, and a layered cutting head end arranged at the distal end of the connecting rod. The layered cutting head end comprises a pair of parallel blades, a pair of depth-limiting baffles, and a tissue separation block arranged between the parallel blades. The width and depth of the graft can be accurately set through a width adjustment mechanism and a depth adjustment mechanism. During the cutting process, the tissue separation block can separate the keratinized gingiva on the surface layer from the deep tissue in situ, so that a pure connective tissue graft is obtained at one time, and the surface epithelium and deep adipose gland tissue of the donor area are completely preserved. The application realizes precise, minimally invasive and integrated cutting of connective tissue, simplifies the surgical operation, reduces the technical threshold, reduces the pain of patients, and improves the success rate of transplantation.

Description

Technical Field

[0001] This invention belongs to the field of oral medical device technology, specifically relating to a surgical knife for layered harvesting of connective tissue grafts from the palatal side of the maxilla. Background Technology

[0002] In dental implantology, periodontology, and gingival surgery, sufficient attached gingival width is crucial for maintaining periodontal health and ensuring long-term implant stability. Connective tissue grafting is one of the most effective surgical methods for widening the attached gingiva and covering the exposed root surface. The core step of this technique is to harvest a connective tissue graft of appropriate size and thickness from the patient's maxillary palatal side.

[0003] Currently, the mainstream method for obtaining palatal connective tissue grafts in clinical practice relies on manual manipulation by doctors using traditional surgical blades (such as 15C blades). This method has several drawbacks and inherent limitations:

[0004] 1. Full-thickness incision combined with in vitro epithelial removal: The surgeon first uses a scalpel to incise a full-thickness soft tissue block, including epithelium and connective tissue, from the palate. Then, the superficial keratinized epithelium is manually removed externally with a blade to obtain pure connective tissue. This method has serious drawbacks: a) Depth control depends entirely on the surgeon's feel, which can easily lead to deep incisions that damage underlying fat and glands, or shallow incisions that result in insufficient connective tissue; b) The in vitro epithelial removal technique is sensitive and can easily damage the integrity of connective tissue fibers, affecting the survival and fusion of the graft; c) It results in the unnecessary discarding of superficial keratinized epithelium and leaves a large full-thickness wound at the donor site, leading to slow healing and significant pain.

[0005] 2. Envelope flap technique: To reduce trauma and directly obtain connective tissue, experienced surgeons use the envelope flap technique. This involves making a single incision in the palate, dissecting to create a submucosal tunnel (envelope), and then harvesting connective tissue from within the tunnel. While this technique preserves the superficial epithelium, it is extremely difficult to perform, requires a deep understanding of local anatomy, is prone to mucosal flap puncture during surgery, has a steep learning curve, and is difficult to promote among general clinicians.

[0006] 3. Attempts at Specialized Instruments: Existing technologies include some instruments for obtaining gingival tissue, such as gingival scalpels with depth-limiting devices. However, these instruments are mostly designed for harvesting full-thickness gingival tissue or for other sites, failing to address the core challenge of "in-situ, layered, and precise thickness" harvesting of connective tissue in the specific anatomical region of the maxillary palatal side. They cannot simultaneously separate the epithelial layer from the connective tissue layer in situ within the body, thus still requiring secondary in vitro processing or complex flap techniques.

[0007] In summary, there has long been a lack of a dedicated tool in this field capable of performing a pre-set width incision, precise depth control, and in-situ tissue layer separation simultaneously during cutting. This has resulted in low efficiency, inconsistent quality, high skill requirements for surgeons, and severe postoperative reactions in patients during connective tissue transplantation surgery, thus hindering the widespread clinical application of this technique. Therefore, developing a surgical instrument that simplifies the procedure, reduces difficulty, and enables precise, minimally invasive harvesting of connective tissue transplants is of significant clinical need and practical importance. Summary of the Invention

[0008] Based on the problems existing in the above-mentioned background technology, the present invention proposes a surgical knife for layered harvesting of connective tissue grafts on the palatal side of the maxilla, which solves the problems of inaccurate depth control, inability to perform in-situ layering, and complex operation in the mainstream methods for obtaining palatal connective tissue grafts in clinical practice.

[0009] The embodiments of the present invention are implemented as follows:

[0010] The present invention provides a surgical knife for layered harvesting of connective tissue grafts on the palatal side of the maxilla, which includes a handle, a connecting rod at the head end of the handle, a layered harvesting head on the connecting rod, and a mounting body fixedly connected to the end of the connecting rod. The mounting body is provided with a pair of parallel blades, a pair of depth limiting baffles and a tissue separation block.

[0011] A pair of parallel blades are horizontally spaced and used to make two parallel incisions in the tissue;

[0012] A pair of depth-limiting baffles are located on the outside of a pair of parallel blades and are used to control the cutting depth of the parallel blades; a tissue separation block is located between a pair of parallel blades and is used to separate the superficial keratinized gingival tissue from the deep tissue during the cutting process.

[0013] The scalpel of this invention for harvesting connective tissue grafts from the palatal side of the maxilla has a pair of parallel blades that define the width boundary of the graft; a pair of depth-limiting baffles, through physical limiting principles, absolutely ensure that the cutting depth will not exceed the preset safety value; during the cutting process, the tissue separation block uses mechanical wedge force or spreading force to conform to the tissue layers and achieve in-situ separation of epithelium and connective tissue; this scalpel enables the direct harvesting of pure, intact, and uniformly thick connective tissue grafts from the donor site, while perfectly preserving the important tissues of the donor site, revolutionarily simplifying the surgical procedure.

[0014] Furthermore, the main body of the device is equipped with a width adjustment mechanism connected to a pair of parallel blades. The width adjustment mechanism can adjust the spacing between the pair of parallel blades, allowing the surgeon to personalize the width of the graft according to the size of the recipient area, greatly improving the versatility of the scalpel and the flexibility of the surgical plan.

[0015] Furthermore, the interior of the main body of the installation unit has a hollow structure, and the width adjustment mechanism includes a lead screw, a guide rod, a slider, and a blade adjustment knob;

[0016] The lead screw and guide rod are arranged parallel to each other inside the mounting body through the mounting base. The lead screw has two symmetrically arranged threaded sections with opposite directions of thread. Each threaded section is threaded with a slider. The top of a pair of parallel blades is connected to the two sliders respectively, and the top of the pair of parallel blades slides with the guide rod.

[0017] The blade adjustment knob is threaded to the side wall of the mounting body, and its end is fixedly connected to one end of the lead screw.

[0018] In the width adjustment mechanism, rotating the blade adjustment knob drives the lead screw to rotate. Because the two ends of the lead screw have opposite threads, the two meshing sliders move synchronously in opposite directions, thus precisely changing the spacing of the parallel blades fixed on the sliders. The guide rod ensures the linearity and stability of the slider movement. The lead screw drive features high precision and self-locking, enabling micron-level spacing adjustment and maintaining a stable set position; bidirectional synchronous movement ensures the blades remain symmetrical about the center.

[0019] Furthermore, the mounting body is equipped with a depth adjustment mechanism connected to a pair of depth limiting baffles. The depth adjustment mechanism is used to adjust the height difference between the lower edge of the depth limiting baffle and the cutting edge of the parallel blade.

[0020] Furthermore, the depth adjustment mechanism includes a synchronizing rod, a baffle adjustment knob, two compression springs, and two connecting posts. The synchronizing rod is located inside the mounting body, and the baffle adjustment knob is threaded to the upper end of the mounting body with its lower end in close contact with the upper end face of the synchronizing rod. The two compression springs are located inside the mounting body on both sides of the synchronizing rod, and their ends are fixedly connected to the lower end face of the synchronizing rod and the inner bottom surface of the mounting body, respectively. The two connecting posts are located at both ends of the synchronizing rod, with the upper end face of each connecting post fixedly connected to the lower end face of the synchronizing rod, and the lower end face of the connecting post located outside the mounting body and fixedly connected to a single depth-limiting baffle.

[0021] In the depth adjustment mechanism, the rotating baffle adjustment knob can press down or release the synchronizing rod. The synchronizing rod, through connecting columns on both sides, drives the two depth-limiting baffles to move up and down as a whole. A compression spring provides an upward restoring force, which balances with the downward pressure of the rotating baffle adjustment knob, making the position of the depth-limiting baffles stable and adjustable. The synchronizing rod ensures that the height of the two depth-limiting baffles is always consistent, guaranteeing a uniform cutting depth.

[0022] Furthermore, the tissue separation block is fixedly connected to the lower end face of the mounting body via a connecting block. The tissue separation block has a wedge-shaped or flat structure with a small thickness at the front and a large thickness at the rear, which can generate a continuously increasing vertical separation force when it is pushed forward, and use mechanical force to perform blunt separation along the natural interface of the tissue.

[0023] Furthermore, the upper surface of the tissue separation block at its maximum thickness is flush with or slightly lower than the cutting edge of the parallel blade, ensuring that the separation block can immediately and fully intervene in the tissue between the cuts after the blade cuts to the preset depth, thus achieving a seamless connection between the "cutting" and "separation" actions.

[0024] Furthermore, the lower edge of the depth-limiting baffle extends below the cutting edge of the parallel blade. The lower edge of the depth-limiting baffle acts as a stop surface; once it contacts the mucosal surface, the parallel blade cannot continue to cut deeper. This provides an absolutely reliable depth safety guarantee, physically eliminating the risk of excessive cutting.

[0025] Furthermore, the lower end face of the mounting body is provided with a width scale to indicate the distance between a pair of parallel blades; a pair of depth-limiting baffles are provided with a depth scale to indicate the cutting depth of the parallel blades. The width and depth scales enable the digitization and recordability of surgical parameters. Doctors can make precise quantitative settings.

[0026] Furthermore, the handle, connecting rod, and layered cutting head are all made of medical-grade stainless steel or titanium alloy.

[0027] In this invention, the method for harvesting maxillary palatal connective tissue grafts using a surgical scalpel includes:

[0028] S1: Based on the supply area, the spacing of the parallel blades is preset through the width adjustment mechanism, and the height difference between the depth limit baffle and the blade edge is preset through the depth adjustment mechanism.

[0029] S2: Place the layered cutting tip of the scalpel on the mucosal surface of the maxillary palatal donor site and press down to make the depth limiting baffle fit tightly against the mucosa.

[0030] S3: Smoothly advance the scalpel forward, allowing the parallel blades to cut into the tissue to the depth defined by the depth limiter. Simultaneously, the tissue separation block enters the incision and separates the tissue layers. Specifically, a pair of parallel blades first cut in, like railway workers laying two parallel tracks, cutting through the epithelium and entering the connective tissue layer. At this point, the tip (thinner part) of the tissue separation block, located between the blades, follows closely behind the blades, entering the tissue area between these two incisions. At this stage, it has not yet begun separation; it is merely being introduced. As the scalpel continues to advance, the thickness of the tissue separation block gradually increases, generating a continuous, gentle but firm vertical (perpendicular to the cutting direction) expansion force on the tissue above and below the separation block. The tissue above (keratinized epithelium and a small amount of connective tissue immediately beneath it) is subjected to an upward force, while the tissue below (the main body of the target connective tissue layer and deeper layers) is subjected to a downward force. At the same time, because the internal structure of the connective tissue layer is loose and the connections are relatively fragile, under the continuous and correctly oriented expansion force, the fibers connecting these points will be stretched, extended, and eventually separated, rather than being cut. This process is similar to "blunt dissection" using a blunt instrument.

[0031] S4: After completing the pre-set length cut, remove the scalpel, use instruments to lift and remove the separated intermediate layer connective tissue graft.

[0032] Compared with the mainstream methods currently used in clinical practice for obtaining palatal connective tissue grafts, the advantages of this invention are:

[0033] This invention discloses a surgical scalpel for layered harvesting of connective tissue grafts on the palatal side of the maxilla. Through width and depth adjustment mechanisms, the width and depth of the graft can be precisely set. During the cutting process, a tissue separation structure can separate the superficial keratinized gingiva from the deeper tissues in situ, thereby obtaining a pure connective tissue graft in a single procedure while completely preserving the superficial epithelium and deep adipose gland tissue of the donor site. This invention achieves precise, minimally invasive, and integrated connective tissue harvesting, simplifying the surgical procedure, lowering the technical threshold, reducing patient suffering, and improving the transplant success rate. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and other objects, features, and advantages of the present invention will become clearer through the accompanying drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not intentionally drawn to scale to actual dimensions; the focus is on illustrating the main points of the invention.

[0035] Figure 1 This is a schematic diagram of a surgical scalpel used for layered harvesting of connective tissue grafts from the palatal side of the maxilla.

[0036] Figure 2 This is a top view of the structure after the head end has been cut in layers.

[0037] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure along the AA direction.

[0038] Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure in the middle BB direction.

[0039] Figure 5 A side view of the structure in which the lead screw and guide rod are installed within the mounting body.

[0040] The components are as follows: 1. Blade holder; 2. Connecting rod; 3. Mounting body; 4. Parallel blade; 5. Depth limiting baffle; 6. Tissue separation block; 7. Lead screw; 8. Guide rod; 9. Slider; 10. Blade adjustment knob; 11. Synchronizing rod; 12. Baffle adjustment knob; 13. Compression spring; 14. Connecting column. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0045] Please refer to Figure 1As shown, the present invention provides a scalpel for layered harvesting of connective tissue grafts on the palatal side of the maxilla, including a handle 1, a connecting rod 2 at the tip of the handle 1, and a layered harvesting tip on the connecting rod 2. Specifically, the handle 1, the connecting rod 2 and the layered harvesting tip are all made of medical-grade stainless steel or titanium alloy.

[0046] The layered cutting tip is the core of this invention. It includes a mounting body 3 fixedly connected to the end of the connecting rod 2. The mounting body 3 is equipped with a pair of parallel blades 4, a pair of depth-limiting baffles 5, and a tissue separation block 6. The pair of parallel blades 4 are horizontally spaced and used to make two parallel incisions in the tissue. The pair of depth-limiting baffles 5 are located on the outer sides of the pair of parallel blades 4 and are used to control the cutting depth of the parallel blades 4. The tissue separation block 6 is located between the pair of parallel blades 4 and is used to separate the superficial keratinized gingival tissue from the deeper tissue during the cutting process. The lower edge of the depth-limiting baffle 5 extends below the cutting edge of the parallel blades 4. The lower edge of the depth-limiting baffle 5 acts as a stop surface; once it contacts the mucosal surface, the parallel blades 4 cannot continue to cut deeper. This provides an absolutely reliable depth safety guarantee, physically eliminating the risk of excessive cutting.

[0047] The technical principle of layered cutting of the graft tip is as follows: a pair of parallel blades 4 are responsible for defining the width boundary of the graft; a pair of depth limiting baffles 5, through the principle of physical limiting, absolutely ensure that the cutting depth will not exceed the preset safety value; during the cutting process, the tissue separation block 6 uses mechanical wedge force or spreading force to follow the tissue layers and realize the in-situ separation of epithelium and connective tissue; this scalpel realizes the direct acquisition of pure, complete and uniformly thick connective tissue grafts from the donor site, while perfectly preserving the important tissues of the donor site, and revolutionarily simplifying the surgical procedure.

[0048] Preferred, but not limited to, such as Figure 2 , Figure 3 and Figure 5 As shown, the mounting body 3 is equipped with a width adjustment mechanism connected to a pair of parallel blades 4. This mechanism allows for adjustment of the spacing between the parallel blades 4, enabling doctors to customize the graft width according to the size of the recipient area, greatly improving the versatility of the scalpel and the flexibility of the surgical plan. The mounting body 3 has a hollow internal structure. As a specific configuration of the width adjustment mechanism, it includes a lead screw 7, a guide rod 8, a slider 9, and a blade adjustment knob 10. The lead screw 7 and guide rod 8 are parallel to each other inside the mounting body 3 via a mounting base. The lead screw 7 has two symmetrically arranged threaded sections with opposite directions of rotation, each threaded section being threadedly connected to a slider 9. The tops of the pair of parallel blades 4 are respectively connected to the two sliders 9, and the tops of both parallel blades 4 slide in engagement with the guide rod 8. The blade adjustment knob 10 is threadedly connected to the side wall of the mounting body 3, and its end is fixedly connected to one end of the lead screw 7.

[0049] In the width adjustment mechanism, rotating the blade adjustment knob 10 drives the lead screw 7 to rotate. Since the two threads of the lead screw 7 rotate in opposite directions, the two meshing sliders 9 move synchronously in opposite directions in a straight line, thereby driving the parallel blades 4 fixed on the sliders 9 to precisely change the spacing. The guide rod 8 ensures the linearity and stability of the slider 9's movement. The lead screw drive has high precision and self-locking properties, enabling micron-level spacing adjustment and maintaining a stable set position; bidirectional synchronous movement ensures that the blades are always symmetrical about the center.

[0050] Preferred, but not limited to, such as Figure 2 and Figure 4 As shown, the mounting body 3 is equipped with a depth adjustment mechanism connected to a pair of depth limiting baffles 5. The depth adjustment mechanism is used to adjust the height difference between the lower edge of the depth limiting baffle 5 and the cutting edge of the parallel blade 4. As a specific arrangement of the depth adjustment mechanism, the depth adjustment mechanism includes a synchronizing rod 11, a baffle adjustment knob 12, two compression springs 13, and two connecting posts 14. The synchronizing rod 11 is located inside the mounting body 3. The baffle adjustment knob 12 is threaded to the upper end of the mounting body 3, and its lower end is in close contact with the upper end face of the synchronizing rod 11. The two compression springs 13 are located inside the mounting body 3 and are located on both sides of the synchronizing rod 11. The two ends of the compression springs 13 are fixedly connected to the lower end face of the synchronizing rod 11 and the inner bottom surface of the mounting body 3, respectively. The two connecting posts 14 are located at both ends of the synchronizing rod 11. The upper end face of each connecting post 14 is fixedly connected to the lower end face of the synchronizing rod 11, and the lower end face of the connecting post 14 is located outside the mounting body 3 and is fixedly connected to a single depth limiting baffle 5.

[0051] In the depth adjustment mechanism, the rotating baffle adjustment knob 12 can press down or release the synchronizing rod 11. The synchronizing rod 11 drives the two depth-limiting baffles 5 to move up and down as a whole through the connecting columns 14 on both sides. The compression spring 13 provides an upward restoring force, which balances with the downward pressure of the rotating baffle adjustment knob 12, making the position of the depth-limiting baffles 5 stable and adjustable. The synchronizing rod 11 ensures that the height of the two depth-limiting baffles 5 is always consistent, ensuring uniform cutting depth.

[0052] Specifically, the tissue separation block 6 is fixedly connected to the lower end face of the mounting body 3 via a connecting block. The tissue separation block 6 has a wedge-shaped or flat structure with a thinner front section and a thicker rear section, which can generate a continuously increasing vertical separation force when advancing forward, using mechanical force to perform blunt separation along the natural interface of the tissue. The upper surface of the tissue separation block 6 at its maximum thickness is flush with or slightly lower than the cutting edge of the parallel blade 4, ensuring that the separation block can immediately and fully intervene in the tissue between the cuts after the blade cuts to the preset depth, achieving a seamless connection between the "cutting" and "separation" actions.

[0053] Preferably, but not limited to, the lower end face of the mounting body 3 is provided with a width scale for indicating the distance between a pair of parallel blades 4; a pair of depth limiting baffles 5 are provided with a depth scale for indicating the cutting depth of the parallel blades 4. The width and depth scales realize the digitization and recordability of surgical parameters. Doctors can make precise quantitative settings.

[0054] In this invention, the method for harvesting maxillary palatal connective tissue grafts using a surgical scalpel includes:

[0055] S1: Based on the supply area, the spacing of the parallel blades 4 is preset through the width adjustment mechanism, and the height difference between the depth limit baffle 5 and the blade edge is preset through the depth adjustment mechanism.

[0056] S2: Place the layered cutting tip of the scalpel on the mucosal surface of the maxillary palatal donor site and press down to make the depth limiting baffle 5 fit tightly against the mucosa;

[0057] S3: Smoothly advance the scalpel forward, allowing the parallel blades 4 to cut into the tissue to the depth defined by the depth-limiting baffle 5. Simultaneously, the tissue separation block 6 enters the incision and separates the tissue layers. Specifically, a pair of parallel blades 4 first cut in, like railway workers laying two parallel tracks, cutting through the epithelium and entering the connective tissue layer. At this point, the tip (thinner part) of the tissue separation block 6, located between the blades, follows closely behind the blades and enters the tissue area between these two incisions. At this stage, it has not yet begun separation; it is merely being introduced. As the scalpel continues to advance, the thickness of the tissue separation block 6 gradually increases, generating a continuous, gentle but firm vertical (perpendicular to the cutting direction) expansion force on the tissue above and below the tissue separation block 6. The tissue above (keratinized epithelium and a small amount of connective tissue immediately beneath it) is subjected to an upward force, while the tissue below (the main body of the target connective tissue layer and deeper layers) is subjected to a downward force. At the same time, because the internal structure of the connective tissue layer is loose and the connections are relatively fragile, under the continuous and correctly oriented expansion force, the fibers connecting these points will be stretched, extended, and eventually separated, rather than being cut. This process is similar to "blunt dissection" using a blunt instrument.

[0058] S4: After completing the pre-set cut, remove the scalpel, use instruments to lift and remove the separated intermediate connective tissue graft. This achieves precise, minimally invasive, and integrated connective tissue harvesting, simplifying the surgical procedure, lowering the technical threshold, reducing patient suffering, and improving the transplant success rate.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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. A surgical scalpel for layered harvesting of connective tissue grafts from the palatal side of the maxilla, characterized in that, The device includes a handle, the head end of which is provided with a connecting rod, and the connecting rod is provided with a layered cutting head. The layered cutting head includes a mounting body fixedly connected to the end of the connecting rod, and the mounting body is provided with a pair of parallel blades, a pair of depth limiting baffles, and a tissue separation block. A pair of parallel blades are horizontally spaced and used to make two parallel incisions in the tissue; A pair of depth-limiting baffles are located on the outside of a pair of parallel blades and are used to control the cutting depth of the parallel blades; the tissue separation block is located between a pair of parallel blades and is used to separate the superficial keratinized gingival tissue from the deep tissue during the cutting process; The mounting body is equipped with a width adjustment mechanism connected to a pair of parallel blades; the interior of the mounting body is hollow, and the width adjustment mechanism includes a lead screw, a guide rod, a slider, and a blade adjustment knob; the lead screw and the guide rod are arranged parallel to each other inside the mounting body via a mounting base, and the lead screw has symmetrically arranged threaded sections with opposite thread directions at both ends, with a slider threaded to the end of each threaded section; the tops of the pair of parallel blades are respectively connected to two sliders, and the tops of the pair of parallel blades are slidably engaged with the guide rod; the blade adjustment knob is threadedly connected to the side wall of the mounting body, and its end is fixedly connected to one end of the lead screw; The mounting body is equipped with a depth adjustment mechanism connected to a pair of depth-limiting baffles. The depth adjustment mechanism is used to adjust the height difference between the lower edge of the depth-limiting baffle and the cutting edge of the parallel blade. The depth adjustment mechanism includes a synchronizing rod, a baffle adjustment knob, two compression springs, and two connecting posts. The synchronizing rod is located inside the mounting body. The baffle adjustment knob is threaded to the upper end of the mounting body, and its lower end is in close contact with the upper end face of the synchronizing rod. The two compression springs are located inside the mounting body on both sides of the synchronizing rod, and their two ends are fixedly connected to the lower end face of the synchronizing rod and the inner bottom surface of the mounting body, respectively. The two connecting posts are located at both ends of the synchronizing rod, and the upper end face of each connecting post is fixedly connected to the lower end face of the synchronizing rod. The lower end face of the connecting post is located outside the mounting body and is fixedly connected to a single depth-limiting baffle. The tissue separation block is fixedly connected to the lower end face of the mounting body via a connecting block. The tissue separation block has a wedge-shaped or flat structure with a small thickness at the front and a large thickness at the rear. When harvesting connective tissue grafts from the maxillary palatal side, place the layered harvesting tip of the scalpel on the mucosal surface of the maxillary palatal donor site and press down to make the depth limiting baffle fit tightly against the mucosa. The scalpel is smoothly advanced forward, allowing the parallel blades to cut into the tissue to the depth defined by the depth limiter. Simultaneously, the tissue separation block enters the incision and separates the tissue layers. A pair of parallel blades cut in first, like railway workers laying two parallel tracks, cutting through the epithelium and entering the connective tissue layer. At this point, the tip of the tissue separation block, located between the blades, follows closely behind the blades, entering the tissue area between these two incisions. As the scalpel continues to advance forward, the thickness of the tissue separation block gradually increases, generating a vertical expansion force on the tissue above and below the tissue separation block. The tissue above experiences an upward force, and the tissue below experiences a downward force. Under the action of the expansion force, the fibers are stretched, extended, and eventually separated. After completing the pre-set length of cut, the scalpel is removed, and the separated intermediate connective tissue graft is lifted and removed using instruments.

2. The surgical scalpel for layered harvesting of connective tissue grafts from the palatal side of the maxilla according to claim 1, characterized in that, The upper surface of the tissue separation block at its maximum thickness is flush with or slightly below the cutting edge of the parallel blade.

3. The surgical scalpel for layered harvesting of connective tissue grafts from the palatal side of the maxilla according to claim 1, characterized in that, The lower edge of the depth-limiting baffle extends below the cutting edge of the parallel blade.

4. The surgical scalpel for layered harvesting of connective tissue grafts from the palatal side of the maxilla according to claim 1, characterized in that, The lower end face of the mounting body is provided with a width scale for indicating the distance between the pair of parallel blades; the pair of depth limiting baffles are provided with a depth scale for indicating the cutting depth of the parallel blades.

5. The surgical scalpel for layered harvesting of connective tissue grafts from the palatal side of the maxilla according to claim 1, characterized in that, The handle, connecting rod, and layered cutting head are all made of medical-grade stainless steel or titanium alloy.

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