Improved handle of prosthesis for reconstruction of ossicular chain

Abstract

An improved total ossicular prosthesis (TORP) for the reconstruction of an ossicular chain, the combination comprising: a head (C) consisting of a single cartilage block; a cylindrical synthetic handle (A), both ends of which are respectively provided with a blunt tip (A1, A2); and a cartilage base (B) having the same thickness as the head (C) but a smaller surface area. An improved total ossicular prosthesis configured to be able to position the head (C) below the tympanic membrane (D) and the base (B) above the floor (E) of the stapes (S), respectively; therefore, in the healing process, the cartilage membrane of the head (C) and the tympanic membrane (D) form biological fixation, and the cartilage membrane of the base (B) and the mucous membrane of the bottom plate (E) form biological fixation.

Description

Technical Field

[0001] The present invention relates to the field of surgery, in particular to ear diseases. Background Art

[0002] The tympanic cavity is an air-filled space connected to the nasal cavity by the Eustachian tube. It contains three small auditory bones: the malleus, the incus, and the stapes, which form the so-called "ossicular chain." The function of this chain is to transmit sound waves from the eardrum to the cochlea. In the cochlea, the mechanical energy of the sound waves is converted into electrical energy—in other words, electrical impulses—which are transmitted to the brain via the auditory nerve. Damage to this chain can lead to hearing loss, known as conductive hearing loss.

[0003] The surgery to rebuild the ossicular chain is called "ossicular chainplasty". Depending on the condition of the damaged ossicles, there are two types of ossicular chainplasty: Partial ossicular chainplasty, when only one ossicle is damaged, the incus; Total ossicular chainplasty, which is when two ossicles are damaged: the incus and the stapes suprastructure.

[0004] The prosthesis used for partial ossicular chainplasty is called a PORP (Partial Ossicular Prosthesis). It is placed between the eardrum and the stapes head to replace the damaged incus. The prosthesis used for total ossicular chainplasty is called a TORP (Total Ossicular Prosthesis). It is placed between the eardrum and the stapes baseplate to replace the damaged incus and stapes superstructure.

[0005] As disclosed in US Pat. No. 4,641,651, a total ossicular prosthesis (TORP) comprises a head and a synthetic stem, wherein the head is made of a cartilage block and the synthetic stem is cylindrical and has a tip at one end. Summary of the Invention

[0006] The present invention can be better understood through the following detailed description in conjunction with the accompanying drawings, which illustrate some prior art solutions and a preferred embodiment of the present invention, which is illustrated and described herein in an exemplary and non-limiting manner.

[0007] In the attached figure: Figure 1 Schematic diagram of the ossicular chain of the human ear; Figure 2 The figures show: the morphology of a known type of synthetic PORP on the left, and the positioning of the PORP between the tympanic membrane and the stapes on the right; Figure 3 The figures show: the morphology of a known type of synthetic TORP on the left, and the positioning of the TORP between the tympanic membrane and the stapes base plate on the right; Figure 4 Shown is a prosthesis for stapes surgery (1) and the same prosthesis modified into a semi-synthetic static TORP of known type (2); Figure 5 The method for making a known type of semi-synthetic TORP with a length of 5 mm and its positioning in total ossicular chain plasty is shown; Figure 6 and Figure 7 and Figure 5 Similarly, semisynthetic TORPs with lengths of 6 and 7 mm were involved, respectively; Figure 8 Shown is an improved TORP manufactured according to the present invention, having an overall length of 5 mm; Figure 9 Shown is an improved TORP manufactured according to the present invention, having an overall length of 6 mm; Figure 10 Shown is an improved TORP manufactured according to the present invention, having an overall length of 7 mm; Figure 11A and Figure 11B The present invention shows the positioning of the prosthesis between the tympanic membrane and the stapes baseplate (for full ossicular chain reconstruction of the incus and the superstructure of the damaged stapes), as well as its behavior under changes in atmospheric pressure; Figure 12 Shown is the positioning of the inventive prosthesis between the intact stapes baseplate and the tympanic membrane (for ossicular chain reconstruction) when only one ossicle (the incus) is damaged.

[0008] Currently used total ossicular prostheses (TORPs) are made of synthetic materials, which can be selected from gold, platinum, hydroxyapatite or titanium. Each TORP consists of a flat head with a diameter of about 2.5 mm, which is placed at the end of a cylindrical handle ( Figure 3 The distance between the tympanic membrane and the stapes base is usually 5 to 7 mm, and rarely 8 mm. The most commonly used total ossicular prosthesis in ossicular chain reconstruction is 5 mm, 6 mm, or 7 mm in total length.

[0009] Existing total ossicular prosthesis (TORP) has the following four major defects: 1-Poor anchoring to the tympanic membrane; 2-Insufficient fixation stability with the stapes baseplate; 3- Unable to adjust length adaptively according to eardrum movement; 4- Low biocompatibility in adverse biological environments.

[0010] Decreases in atmospheric pressure (such as those experienced during air travel or mountain climbing) can increase intratympanic pressure, causing the tympanic membrane to shift 1 to 1.5 mm laterally. Commercially available prostheses are static and, because they cannot change length, can easily lose contact with the tympanic membrane and stapes footplate and become displaced. Similarly, increases in atmospheric pressure (such as those experienced during diving) or Eustachian tube dysfunction can cause intratympanic pressure to decrease, leading to inward displacement of the tympanic membrane. Increased tension between the tympanic membrane and the synthetic prosthesis can cause the prosthesis to dislodge. Such prosthetic dislocation or displacement can lead to a recurrence of conductive hearing loss.

[0011] This is why, for a long time, total ossicular prostheses (TORPs) made of synthetic materials have had a high rate of long-term dislodgement or displacement (35% to 55%). To address or at least reduce the recurrence rate of conductive hearing loss, the applicant proposed and published a new total ossicular prosthesis called "semi-synthetic TORP" (hereinafter referred to as TORPss) in 2007.

[0012] The TORPss is made by assembling a cylindrical titanium-polytetrafluoroethylene composite handle with an autologous tragus cartilage. Specifically, the handle is made by cutting a known type of stapes surgical prosthesis (made of titanium-polytetrafluoroethylene) with a total length of 7 mm (see Figure 4 A) Basal segment of the hook.

[0013] Thus, a titanium-polytetrafluoroethylene composite cylindrical handle with a diameter of 0.4 mm and a length of 4 mm was obtained. The handle was equipped with an integrally formed blunt titanium tip with a tip diameter of 0.2 mm and a length of 1 mm ( Figure 4 B). The blunt titanium tip is fully inserted into the head of the tragus cartilage ( Figure 5 Specifically, the head of the TORPss can be composed of one to three pieces of tragus cartilage connected by perichondrial hinges ( Figure 5 、 6 , 7). Tragus cartilage is an ideal structural unit material due to its 1 mm thick planar properties. The 5 mm long TORPss uses a single 2.5 × 2.5 mm square piece of tragus cartilage as the head, covered on both sides with perichondrium. An insulin needle is used to create a hole in the center of the perichondrium, and the blunt titanium tip of the handle is then inserted into the hole. A slight pressure is applied to completely embed the tip into the cartilage. This results in a 5 mm long TORPss ( Figure 5 The assembled structure of the cartilage block and the handle shows high stability. The tragus cartilage head is placed under the tympanic membrane, and the base end of the synthetic handle is fixed above the stapes base plate, so that the whole ossicular chain can be reconstructed ( Figure 5 ).

[0014] A 6 mm long TORPss was made by assembling the stem with two tragus cartilage pieces fixed by a perichondrial hinge ( Figure 6). Similarly, a 7 mm long TORPss was made by assembling the stem with three tragus cartilage pieces, which were fixed by perichondrial connections ( Figure 7 ).

[0015] However, it should be noted that this TORPss only solves two of the four defects of synthetic TORP, specifically: 1- The head of the tragus cartilage contacts the tympanic membrane through the perichondrium, forming a biological fixation with the tympanic membrane during the healing process and will not detach even in pathological conditions; 2-The anchoring effect between the base end of the TORPss and the stapes baseplate is still unsatisfactory; 3-The TORPss is still a static prosthesis and cannot be adjusted in length according to the movement of the tympanic membrane; 4- Under pathological conditions, the TORPss can still maintain high biocompatibility and prevent the prosthesis from falling out because the cartilage of the tragus blocks the direct contact between the synthetic stem and the tympanic membrane.

[0016] The TORPss had a significantly reduced rate of expulsion and tympanic membrane displacement, but the problem of displacement of the base end of the handle from the stapes baseplate remained unresolved.

[0017] The defects of TORPss are specifically reflected in the following aspects: 1- There are technical differences in the tragus cartilage head structure of the TORPss: the 5 mm long TORPss is relatively simple with a single piece of tragus cartilage, while the 6 mm or 7 mm long TORPss requires two to three pieces of tragus cartilage to be connected by a cartilage hinge, and the assembly process requires a high level of operator experience.

[0018] 2- The prosthesis is still a static prosthesis. When the atmospheric pressure changes and causes the distance between the eardrum and the stapes base plate to increase, the length cannot be extended.

[0019] 3- The lack of anchoring between the base end of the synthetic stem and the stapes baseplate and the inability to adjust the length make the stem prone to displacement in the unanchored state (especially when the atmospheric pressure changes), thereby causing the recurrence of conductive hearing loss.

[0020] The main purpose of the present invention is to overcome the above-mentioned defects and provide an improved total ossicular prosthesis that is innovative compared to the traditional TORPss.

[0021] The improved total ossicular prosthesis of the present invention is characterized by having a modular structure, comprising: -The head is made of a piece of tragus cartilage covered with perichondrium (thickness 1 mm, surface area 2.5×2.5 mm), and its construction process is simple ( Figure 8 、 9 , 10); - A new synthetic cylindrical handle with blunt titanium tips of 0.2 mm diameter and 1 mm length at each end ( Figure 8 、 9 , 10); -Base composed of a piece of tragus cartilage covered with perichondrium (thickness 1 mm, surface area 0.8 × 0.8 mm) ( Figure 8 、 9 , 10); The length-adjustable property of the semi-synthetic prosthesis is achieved by adopting cylindrical synthetic handles of different lengths.

[0022] According to the present invention, the tip (A1) at one end of the handle (A) is completely inserted into the interior of the prosthesis head (C) composed of a piece of tragus cartilage covered by the perichondrium, and the tip (A2) at the opposite end of the handle (A) is completely inserted into the interior of the prosthesis base (B) composed of a piece of tragus cartilage smaller in size than the piece of tragus cartilage used in the head. Figure 8 、 9 , 10).

[0023] Therefore, combined Figure 8 、 9 As shown in FIG. 10 , the improved total ossicular prosthesis (TORP) of the present invention comprises the following structure: The head is composed of a piece of tragus cartilage with a thickness of 1 mm and a surface area of 2.5 × 2.5 mm. A synthetic cylindrical shank (made of at least one material selected from the group consisting of gold, platinum, titanium, and polytetrafluoroethylene) with a diameter of 0.4 mm and a blunt titanium tip of 0.2 mm in diameter and 1 mm in length at each end, the length of the shank corresponding to: 3mm (for 5mm total length Total Ossicular Prosthesis (TORP)) ( Figure 8 ); 4mm (for Total Ossicular Prosthesis (TORP) with a total length of 6mm) ( Figure 9 ); 5mm (for Total Ossicular Prosthesis (TORP) with a total length of 7mm) ( Figure 10 ); The base thickness of the tragus cartilage block is 1 mm, and the surface area is 0.8 × 0.8 mm.

[0024] In ossicular chain reconstruction surgery, the head of the novel prosthesis of the present invention is placed below the tympanic membrane, and its base end is fixed above the stapes base plate ( Figure 11A ).

[0025] Advantageously, during the healing process, the perichondrium of the head forms a biological fixation to the tympanic membrane, and the base perichondrium forms a biological fixation to the mucosa of the stapes baseplate. Therefore, the improved total ossicular prosthesis (TORP) described in the present invention achieves high stability through dual, secure anchoring structures to the tympanic membrane and the stapes baseplate. In contrast, conventional TORPs only have a unilateral anchoring structure to the tympanic membrane, resulting in relatively insufficient stability.

[0026] In addition, compared with the traditional TORPss, the TORP prosthesis of the present invention has a simpler construction process and can achieve a more stable reconstruction of the ossicular chain even when the distance between the eardrum and the stapes base increases due to changes in atmospheric pressure. In such cases, the blunt titanium tips at both ends of the handle can still partially fit into the corresponding holes in the head and base, thereby effectively preventing the prosthesis from shifting ( Figure 11A and 11B ).

[0027] Figure 11A The semi-synthetic dynamic prosthesis of the present invention is shown positioned between the tympanic membrane (D) and the stapes baseplate (E).

[0028] Figure 11B The figure shows the dynamic response characteristics of the prosthesis when the tympanic membrane (D) displaces toward the external auditory canal (CUE), causing the distance between the tympanic membrane (D) and the stapes base (E) to increase: at this time, the tip (A1) of the handle (A) is exposed from the prosthesis head (C), and the other end tip (A2) of the handle (A) is exposed from the prosthesis base (B).

[0029] Figure 12 The semi-synthetic dynamic prosthesis is shown to be arranged between the tympanic membrane (D) and the stapes base plate (E) of the intact stapes (S).

[0030] illustrate: A: Synthetic handle, 3mm, 4mm or 5mm in length A1: The tip of the stem (1 mm in length) needs to be inserted into the prosthesis head B: The prosthesis base consists of a piece of tragus cartilage covered with perichondrium (thickness 1 mm, surface area 0.8 × 0.8 mm) C: The prosthetic head consists of a piece of tragus cartilage covered with perichondrium (thickness 1 mm, surface area 2.5 × 2.5 mm) A: Synthetic stem of the prosthesis A1: The tip of the handle is completely inserted into the head A2: The tip of the handle is completely inserted into the base B: The prosthesis base is composed of cartilage covered by perichondrium B1: The base of the perichondrium forms a biological fixation with the stapes base plate E C: The prosthetic head is composed of a piece of tragus cartilage covered with perichondrium C1: The perichondrium of the head forms a biological fixation with the tympanic membrane D D: Tympanic membrane E: Stapes footplate CUE: external auditory canal.

Claims

1. An improved total ossicular prosthesis (TORP) for ossicular chain reconstruction, characterized by: The combination includes: the head (C), which is composed of a single mass of cartilage and is provided with holes; a cartilaginous base (B) provided with pores and having the same thickness as the head (C) but with a smaller surface area; a cylindrical composite handle (A) with a blunt tip (A1, A2) at each end, the blunt tips (A1, A2) being inserted into corresponding holes in the head (C) and base (B), respectively; The improved total ossicular prosthesis (TORP) is configured to position the head (C) below the tympanic membrane (D) and the base (B) above the base plate (E) of the stapes (S); thereby, during the healing process, the perichondrium of the head (C) forms a biological fixation with the tympanic membrane (D), and the perichondrium of the base (B) forms a biological fixation with the mucosa of the base plate (E).

2. Improved Total Ossicular Prosthesis (TORP) according to the preceding claims, characterized in that: The tip (A1) at one end of the handle (A) is designed to be completely inserted into the head (C) composed of a cartilage block covered by the perichondrium, while the tip (A2) at the other end of the handle (A) is designed to be completely inserted into the base (B) composed of a cartilage block smaller than the head (C).

3. An improved total ossicular prosthesis (TORP) according to any preceding claim, characterised in that: It has an overall length of 5 mm, 6 mm or 7 mm and comprises: The cartilage head covered with perichondrium (C) has a thickness of 1 mm and a surface area of 2.5 × 2.5 mm; The cylindrical synthetic handle (A) is made of gold, platinum, titanium or titanium-polytetrafluoroethylene composite material, with a diameter of 0.4 mm and a blunt tip (A1, A2) with a diameter of 0.2 mm and a length of 1 mm at each end. The length of the handle (A) corresponds to: 3 mm (for total ossicular prosthesis (TORP) with a total length of 5 mm); 4 mm (for total ossicular prosthesis (TORP) with a total length of 6 mm); 5 mm (for total ossicular prosthesis (TORP) with a total length of 7 mm); The cartilage base covering the perichondrium (B) has a thickness of 1 mm and a surface area of 0.8 × 0.8 mm.

4. An improved total ossicular prosthesis (TORP) according to any preceding claim, characterised in that: The length of the blunt tips (A1, A2) is configured so that when the atmospheric pressure changes, the blunt titanium tips (A1, A2) located at both ends of the handle can still at least partially remain inserted into the corresponding holes of the head (C) and the base (B), thereby effectively avoiding displacement.

5. An improved total ossicular prosthesis (TORP) according to any preceding claim, characterised in that: The length of the handle (A) is greater than the height of the stapes (S), so that the improved total ossicular prosthesis can be used for ossicular chain reconstruction in the following two situations: when only one ossicle (i.e., the incus) is damaged, and when both ossicles (i.e., the incus and the superstructure of the stapes (S)) are damaged.

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