ES2470467A1 - Conical device for the injection of biocements (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Conical device for the injection of biocements. Injection device for biocements and/or injectable biomaterials for filling bone cavities comprising a tube or cannula with a conical inner section, the proximal diameter being greater than the distal diameter. The inner conical profile of the cannula guarantees a profile of smooth, continuous and increasing injection flow rates that minimizes the efforts of the surgeon and facilitates the injectability and homogeneity of the biocement and the complete filling of the bone cavity. The new cannula is accompanied by a solid mandrel that fits perfectly to the inner profile of the cannula to give the whole mechanical stability during the operations of puncture and initial perforation of the bone tissue. The new design offers clear advantages over the current cannulas of constant straight section and widens the use of the biocements in traumatology and dentistry with the appropriate geometries. (Machine-translation by Google Translate, not legally binding)

Description

Cynical device for injection of biocements

Object of the invention

The present invention relates to a device to facilitate the injection of injectable biomaterials and / or biocements into a cavity or bone tissue that is filled in order to restore the biological and biomechanical balance of the implanted area. Said device is formed by a conical cannula (C) and a mandrel (M) with the inner taper of the cannula used as a reinforcing element in the initial puncture and perforation of bone tissue. The distal diameter (DD) of the proposed cell has, in a preferred action of the invention, the maximum value allowed to cause minimal damage in a pedicle perforation in a vertebra, while the proximal diameter (DP) is larger than the distal The proposed new cell can inject polymeric and / or ceramic biocements into a vertebra with a lower injection pressure compared to other non-conical geometries. In addition, the new device allows to obtain a profile of unique, smooth and continuous flow rates, along and inside the cell during the entire injection process. This new flow velocity profile makes it possible to reduce the pressure filtration problems of the liquid and powder phases in the case of ceramic biocements, thereby maintaining the material homogeneity of the injected biocement.

Background of the invention

Spine surgery is very demanding and minimally invasive approach techniques such as vertebroplasty and kyphoplasty use cells to inject biocements and stabilize compressive vertebral fractures. The cannulas are basically used to drive the biocement or stabilization biomaterial contained in a syringe and / or piston-type plunger mechanism into the bone tissue cavity and / or vertebra to be filled. Currently there are a wide variety of shapes and dimensions of cells for vertebroplasty (VP) and kyphoplasty (CP) but in all cases the section is constant throughout its length and / or at the proximal and / or distal distances. However, these geometries do not seem to help minimize the problems encountered during clonic practice, such as the extravasation of the biocement into the medullary canal, the pressure filtering of ceramic biocements or the high injection pressure, which greatly complicates the surgical technique when having to resort to auxiliary mechanical devices that hinder the surgeon's manual sensitivity. In fact, the difficulty of the clonic application has motivated the realization of theoretical and experimental studies to understand the injectability properties of the biocements (Bohner et al. Biomaterials 2005; 26: 1553-1563. Habib et al. Acta Biomaterialia 2008; 4 : 1465-1471, Habib et al. Acta Biomaterialia 2010; 6: 250256), the problems associated with the injection of biocements into porous structures (Bohner et al. Biomaterials 2003; 24: 2721-2730) or the biomechanics of injection (Baroud et al. Bio-Medical Materials and Engineering 2004; 14: 487-504. Gisep et al. Bio-Medical Materials and Engineering 2009; 19: 415-420). Studies have also been conducted to measure the injection pressure in vertebral models ex vivo (Baroud et al. Spine 2004; 30 (1): 68-74) and during clone practice (Krebs et al. Spine 2005; 30 (5) : E118-E122). All these studies have been carried out with straight section cells or under the hypothesis of a straight section cell conduction. These and other similar studies of the state of the art have caused changes in the geometry of the cells to reduce the necessary injection pressure by the surgeon, as for example in Baroud et al. Spine 2006; 31 (1): 115-119 proposing a straight cannula with two sections, the proximal section being double diameter to the distal section, which improves the pressure results measured with conventional cannulas of the same distal diameter and identical total length of cannula.

However, the new conical cannulas proposed in this invention improve the functionality of the injection device and the surgical technique since the flow velocity profile that is established inside the new conical cannulas it is monotonically increasing, from a minimum value at the entrance in the proximal zone to a maximum value at the exit in the distal zone. This behavior differs from that observed in conventional straight section cells, where the flow rate is kept constant over the entire fixed diameter cell length with a maximum speed value.

Therefore, the new flow velocity profiles minimize the negative effects of pressure filtration of the biocement while maintaining the homogeneity of the injected pulp and its ability to be extruded. Consequently, the complete filling capacity of the vertebral body and its adequate biomechanical restoration are improved.

In summary, the final objective of this patent is the definition of a cannula with internal taper capable of reducing the required injection pressure in a clonic application that guarantees a more homogeneous and smooth extrusion of the biocement than that obtained with Conventional cannulas with the same distal diameter and constant straight section.

Description of the invention

The present invention implements a bone biocement injection device formed by a cannula (C) characterized by having an area with a length (LTC) of inner conical section. The zone of length LTC has at its distal end a flow opening or outlet of distal diameter DD. Likewise, the LTC zone has at its proximal end a flow inlet towards the LTC conical zone of proximal diameter DP, DP being greater than DD. The LTC zone, at its proximal end DP, extends along a length LO of straight section and constant diameter DP. The total length LT of the new cell is LTC plus LO, with LTC being much greater than LO. The zone of length LO and constant section DP may contain an overlock threading system to allow rapid connection to other biocement dosing systems such as syringes and / or guns.

The novelty of the new injection device resides in the conical zone of LTC length which allows, unlike the current cells of straight interior section and constant diameter DD, to establish inside the cannula and along LTC length profiles of smooth, continuous and increasing flow rates from the proximal zone DP to the distal zone DD of the cell, the minimum flow rate being in the proximal area DP and reaching the maximum value in the distal zone DD . On the contrary, the current straight section and constant diameter DD cells, along their entire length, establish profiles of constant flow rates of maximum value from the entrance to the exit of the cannula, for a fixed value of the diameter distal DD. One of the advantages of the new injection device is that it allows, thanks to the new flow velocity profiles established inside the conical area, to minimize the negative effects of pressure filtration observed during the injection of ceramic biocements, facilitating consequently its injectability and the homogeneity of its properties. Also, the new design allows to reduce the clonic manual pressure required by the surgeon during the entire injection procedure.

The cannula C is accompanied by a solid mandrel M whose diameter and outer taper coincides with the inside of the cannula C in maximum contact position to facilitate its adjustment and its use destined to the puncture and initial perforation of the bone tissue and / or vertebral body. The body of the mandrel M is divided into two distinct zones: the distal zone of LTC length with the same outer taper as the cannula and tipped, which facilitates the perforation of the vertebra, and the proximal area of greater length or equal to LO as a non-cynical cylinder and a pusher. The tip and pusher of the mandrel can acquire shapes and cuts similar to those found in standard models.

Description of the drawings

To complete the description of the new C-cell and of the M-mandrel and to help a better understanding of the features of the invention, according to a preferred example of the practical realization thereof, an integral part of said description is attached, an set of drawings in which, with an illustrative and non-limiting nature, the following has been represented:

Figure 1 shows a view of the placement and / or position of the C cell in a single-pedic approach to fill the inner body of a vertebra. The figure shows the distal diameters DD and proximal DP of the C cell.

Figure 2 shows a perspective view of the conical cannula C and the mandrel M separately and in the coupling position.

Figure 3 shows a sectional view of the new conical cannula C, with references to the distal diameter DD, the proximal diameter DP, the total length of the cannula LT and the straight section length LO in the proximal end also of DP diameter, with the detail of overlock threading.

Preferred Embodiment of the Invention

The proposed invention concerns a cannula inner section cannula for injecting biocements that has advantages, as described, with respect to the models existing in the state of the art. The cannula described here has the same distal diameter (DD) or light input as the rest of the cannulas, standardized according to the G measurement scale, present in the market but with a larger proximal diameter (DP). The new cannula allows to inject under equal conditions biocements with a lower injection pressure. In addition, the new cannula shows a profile of homogeneously distributed flow rates, without sharp spatial increases, along the length of the cannula between the proximal diameter DP, where the fluid velocity is minimal, and the distal diameter DD, where the velocity of the fluid reaches its maximum value. The new profile of

speeds established along the LTC length of the conical cannula favors the homogeneity of the biocement during dosing and minimizes the effects of pressure filtration observed in ceramic biocements formed by a solid powder phase and a liquid phase . The new design of the cannula cannula is clearly new, since in the current straight section cells the flow velocity profile that is established along the cannula is constant throughout its entire length and also reaches the maximum possible value for a value of the established DD distal diameter. The new design also improves the velocity profile observed in straight cells with narrow passage from a straight section of proximal diameter DP greater than a straight section of distal diameter DD smaller since in the narrow zone of throttling or connection an increase is observed abrupt in the flow rate from a constant minimum value, in the proximal zone, to

10 a constant maximum value, in the distal zone, along the respective proximal and distal variable lengths of the straight section cell.

The proposed cannula also contains a threaded overlock type system for its quick and easy connection to other dosing systems. It is presented together with the conical mandrel used as a reinforcing element during the puncture of bone and / or vertebral tissue when incorporated into the interior of the cannula. The same

15 taper allows the perfect fit between both.

Claims (7)

1.- Device for injecting biocements and / or injectable biomaterials, comprising a C-cell and an M-mandrel, characterized in that both pieces have a conical revolution geometry along its longitudinal symmetry axis. 5. Device for injecting biocements and / or injectable biomaterials, according to claim 1, characterized in that the mandrel M is solid and fits perfectly to the empty and conical inner body of the C-cell, forming a single body in the position of maximum contact that offers mechanical resistance to the assembly during the drilling operations of the bone tissue. 3. Device for injecting biocements and / or injectable biomaterials, according to previous claims, 10 characterized in that the C cell has the same distal diameter DD normalized in the G scale and equivalent total lengths as the current commercial cells of constant section. 4. Device for injecting biocements and / or injectable biomaterials, according to previous claims, characterized in that the cell C has a proximal diameter DP greater than the distal diameter DD. 5. Device for injecting biocements and / or injectable biomaterials, according to previous claims, 15 characterized in that the cannula C can have at its proximal end a straight finish of length LO containing an overlock threading system to facilitate its connection to other syringe-type cement systems and / or injection gun. 6. Device for injecting biocements and / or injectable biomaterials, according to previous claims, characterized in that the C-cell and the M-mandrel are manufactured without exclusion, preferably with 20 biomedical grade metal alloys. FIG. one 6 FIG. 2 7 FIG. 3 8 SPANISH OFFICE OF THE PATENTS AND BRAND Application No.: 201231982 SPAIN Date of submission of the application: 20.12.2012 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE 51 Int. Cl.: A61B17 / 56 (2006.01) A61M25 / 06 (2006.01) RELEVANT DOCUMENTS

Category

56 Documents cited Claims Affected

TO

US 2009 149860 A1 (SCRIBNER ROBERT M et al.) 11.06.2009, 1-6

paragraph [0032]; figure 6.

TO

EN 2297061 T3 (PAJUNK GMBH & CO KG BESITZVERW) 01.05.2008, 1-6

figures 1-2.

TO

ES 2304400 T3 (KYPHON INC) 16.10.2008, 1-6

Figures 1-12.

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of realization of the report 04/19/2013

Examiner T. Verdeja Matías Page 1/4

REPORT OF THE STATE OF THE TECHNIQUE Application number: 201231982 Minimum documentation searched (classification system followed by classification symbols) A61B, A61M Electronic databases consulted during the search (database name and, if possible, terms of search used) INVENES, EPODOC State of the Art Report Page 2/4  WRITTEN OPINION Application number: 201231982 Date of Completion of Written Opinion: 04/19/2013 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims Claims 1-6 IF NOT

Inventive activity (Art. 8.1 LP11 / 1986)

Claims Claims 1-6 IF NOT

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION Application number: 201231982  1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

US 2009 149860 A1 (SCRIBNER ROBERT M et al.) 06.11.2009

 2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement The purpose of the request consists of six claims, the first being independent and the other five dependent on she. Said object refers to a device of conical inner section for the injection of biocements. Claim 1 discloses that said device is composed of a cannula and a mandrel having both pieces geometry of conical revolution along its axis of longitudinal symmetry. The document closest to the object of the request is document D01. References in parentheses refer to said document. Said document discloses a device (100) with cannula (170) and mandrel (220), whose geometry is not conical but cylindrical. Mention is made only in paragraph [0032] of a conical design only for the distal end of the device. The difference between the state of the art and the object of the request lies in the configuration of the total section of the device. The request is completely cynical along its entire longitudinal axis, producing this configuration a different technical effect, which affects the flow velocity profile that is established inside the cell. Therefore, it is considered that the object of the application, of claims 1 to 6, is new and has inventive activity (Art. 6.1 and Art. 8.1 LP 11/1986). State of the Art Report Page 4/4