WO2009047286A1

WO2009047286A1 - Surgical spring for final fixing of cranial operculum following to neurological craniectomy

Info

Publication number: WO2009047286A1
Application number: PCT/EP2008/063521
Authority: WO
Inventors: Paolo Di Emidio
Original assignee: Paolo Di Emidio
Priority date: 2007-10-11
Filing date: 2008-10-09
Publication date: 2009-04-16
Also published as: ITTS20070008A1

Abstract

The present surgical instrument is composed of a single wire (2) (of biocompatible material) and a single soldering (3), and uses the general principle of springs. It is structured in such a way to reproduce two geometrical figures: a complete circle (4) at the lower end and a semicircle (5) at the upper end. The two structures are connected by a connection rod (6), which is situated in the centre of the two geometrical figures. The upper end of the semicircle (4) is not soldered and is structured in such a way to minimise the elongation of the spring. The aforementioned surgical spring (1) is used in neurosurgery, in particular in the final phase of craniectomy. The positioning of at least three springs (1) on the borders of craniectomy allows to position, contain and hold the cranial operculum removed during craniectomy.

Description

Surgical spring for final fixing of cranial operculum following to neurological craniectomy.

The use of craniectomy in the treatment of patients with intra and extracerebral injuries has seen a strong impulse in recent years. Indications for craniectomy exist in traumatic injuries, cerebral ischemic injuries, vascular injuries and, in particular, in poor grade patients for the presence of extensive tumours invading the cranial bone structures.

Numerous studies show that the surgical reconstruction of craniolacuny is necessary in the majority of surgically treated patients, with special reference to decompressive craniectomy following to head injury. Such a method can be actuated in a single surgical action, using the autologous cranial operculum, or with alternative methods that provide for the reconstruction of the bone theca with synthetic material. The use of the autologous bone is preferable for excellent biocompatibility and very low cost; however, it has some disadvantages, such as relative reabsorption, impossibility to fill large sines and the necessary use of synthetic methods to fix the fragments.

The synthetic acrylic resin can be defined as an excellent material for the realization of cranioplasty. The technique provides for preparing the resin by mixing a powder component and a liquid component in the operating room. The advantages are the acceptable aesthetic result for small sines and the possibility to model imperfections easily during the operation. The disadvantages of mixing in the operating room are the exothermic reaction of the mix, the dispersion in the room, the presence of air bubbles that can give lower resistance and consequently lower protection against shocks. Hydroxyapatite is an inorganic substance, although it is produced and reabsorbed by organic structures and is the main mineral component of bones. The advantages are the porosity that allows for bone tissue regeneration, high bio-compatibility and possibility of use also in case of previous rejections of cranioplasty. With the use of custom-made cranioplasty in hydroxyapatite, surgical time is considerably reduced. The disadvantage is a certain degree of fragility that persists even some months after implant. In spite of being more recent than other materials, such as metals and polymers, the latter material is the most adaptable material for the biological system and, most of all, the most suitable material to satisfy patients both aesthetically and functionally, due to the use of highly- industrialised techniques for modelling of custom-made prosthesis. All the aforementioned systems need containment with biocompatible synthesis materials.

Numerous systems are currently available to contain the infrastructure, either autologous or synthetic ones. One of the most popular systems consists in the use of titanium plates and screws. The procedure provides for the perforation of numerous holes with a suitable drill and a series of calibrated burrs to contain the corresponding screws. The holes are drilled both on the operculum and on the border of craniotomy; then, fixing is carried out with specific plates. In spite of its validity, the system is impaired from the operative viewpoint by the requirement to use numerous surgical instruments, thus inevitably extending the duration of the surgical operation. Other systems that want to obtain the same results are available, although they require the use of indaginous procedures.

The purpose of the present invention is to eliminate the disadvantages of the known technique by providing a surgical spring that may be used to fix the cranial operculum without the use of other surgical instruments. Another purpose of the present invention is to provide such a surgical spring characterised by reliability, efficiency and at the same time practical and easy use for the operator.

These purposes have been achieved by the invention with the characteristics illustrated in the attached independent claim 1. Advantageous embodiments of the invention will be disclosed from the dependent claims. The surgical spring of the invention comprises: a lower structure designed to be positioned inside the cranial table, between table and dura mater, and an upper structure connected to the lower structure with connection means of spring type. In this way, the lower structure is held steady inside the cranial table and the upper structure may be moved with respect to the lower structure to contain and hold the cranial operculum in a stable way.

As an alternative to the systems that are currently used, the surgical spring of the invention complies with the requirements necessary to guarantee the stability and containment of the cranial operculum. The simplicity and rapidity of use (without other surgical instruments) considerably reduce intra- operation time.

Additional characteristics of the invention will become more evident from the detailed description below, which refers to a merely illustrative, not limiting, embodiment, as shown in the enclosed figures, wherein.

- Fig. 1 is a perspective view of the surgical spring of the invention;

- Fig. 2 is a top view of the surgical spring of Fig. 1 ; and

- Fig. 3 is a front view of the surgical spring according to the direction of the arrow A of Fig. 1. The aforementioned figures illustrate the surgical spring of the invention, identified as a whole with numeral 1 .

The surgical spring (1 ) is composed of a single wire (2) and a single soldering (3). The wire (2) is made of biocompatible metal or coated with biocompatible material and the soldering (3) is made of biocompatible soldering material.

The wire (2) is bent in such a way to reproduce a spring composed of two structures shaped as geometrical figures arranged on two different planes and suitably connected. The following structures are obtained: a first structure (4) shaped as a complete circle at the lower end, and - a second structure (5) shaped as a semicircle at the upper end. The two structures (4) and (5) are combined by a connection rod (6) that extends in axial direction with respect to the centres of the two aforementioned geometrical figures.

Starting from the lower end (10), the wire (2) is bent in such a way to form a circle (4) that is closed with soldering (3). The wire (2) is bent on the soldering (3) along an angular portion (12) in such a way to form a first radial rod (1 1 ) that is directed towards the centre of the circle (4).

As shown in Fig. 3, the radial rod (1 1 ) is slightly inclined downwards, with respect to the plane defined by the circle (4). The radial rod (1 1 ) is bent in the circle (4) along an angular portion (13) in such a way to form the connection rod (6) that extends vertically along the axis of the circle (4). The angular portion (13) forms an acute angle slightly lower than 90°.

After a section with length equal to the diameter of the circle (4), the axial rod (6) is bent along an angular portion (14) in such a way to form a second radial rod (15). The angular portion (14) forms an acute angle slightly lower than 90°.

The second radial rod (15) extends for a length equal to the diameter of the circle (4), and is bent in the angular portion (16) in such a way to form a semicircular section (20). The semi-circular section (20) is bent in an angular portion (17) in such a way to form a third radial rod (18). The end of the third radial rod (18) is drawn close to the axial rod (6) and left free, without soldering. Therefore, the two radial rods (15, 18) and the curved section (20) form the semicircular upper structure (5). It must be noted that the three radial rods (1 1 , 15, 18) basically have the same length, and therefore the circular lower structure (4) has the same diameter as the semi-circular upper structure (5). Moreover, the semi-circular upper structure (5) lays on a plane parallel to the plane of the circular lower structure (4). The special structure of the spring (1 ) allows to rotate the semi-circular upper structure (5) with respect to the circular lower structure (4), thus minimising the elongation of the spring in axial direction.

This description continues with the method of use of the surgical spring of the invention. After performing a craniectomy and removing the bone operculum, the necessary surgical procedure is performed (evacuation of haematoma, aneurysm, tumour, etc.). The cranial operculum must be replaced and fixed at the end of the surgical operation.

The use of the aforementioned surgical springs (1 ) provides for the insertion of at least three springs on the border of the cranial theca in such a way to make the lower part of the spring (4) (complete circle) fall inside the table and between table and dura mater. The rectilinear part (15, 18) of the semicircular upper structure (5) must fall flush to the craniotomic border.

With such a structure, at the borders of cranioctomy, the springs (1 ) can contain the cranial operculum. The cranial operculum is supported by the circular lower structure (4) of the spring. The simple rotation of the semicircular upper structure (5) by one fourth of a turn allows to contain the cranial operculum.

Claims

1 ) Surgical spring (1 ) for final fixing of cranial operculum following to neurological craniectomy, comprising: a lower structure (4) designed to be fixed inside the cranial table, between table and dura mater, and - an upper structure (5) connected to the lower structure (4) with spring connection means (1 1 , 15), in such a way that the upper structure (5) can be moved with respect to the fixed lower structure (4) to contain and hold the cranial operculum in a stable way.

2) Surgical spring (1 ) as claimed in claim 1 , characterised in that the lower structure (4) is shaped as a circle and the upper structure (5) is shaped as a semicircle.

3) Surgical spring (1 ) as claimed in claim 2, characterised in that the circular lower structure (4) and the semi-circular upper structure (5) lay on parallel planes. 4) Surgical spring (1 ) as claimed in claim 2 or 3, characterised in that the circular lower structure (4) and the semi-circular upper structure (5) have the same diameter.

5) Surgical spring (1 ) as claimed in any of claims 2 to 4, characterised in that the connection means comprise an axial rod (6) that extends along an axis passing through the two centres of the circular lower structure (4) and the semicircular upper structure (5).

6) Surgical spring (1 ) as claimed in any claim 3 to 5, characterised in that the circular lower structure (4) and the semi-circular upper structure (5) are situated at a distance equal to their diameter. 7) Surgical spring (1 ) as claimed in any of the above claims, characterised in that it is obtained from a single wire (2).

8) Surgical spring (1 ) as claimed in claim 7, characterised in that the wire (2) is made of biocompatible material or coated with biocompatible material.

9) Surgical spring (1 ) as claimed in claim 7 or 8, characterised in that it comprises a single soldering (3) to close the circle that forms the lower structure (4).

10) Surgical spring (1 ) as claimed in claim 9, characterised in that soldering (3) is made of biocompatible soldering material.

1 1 ) Surgical spring (1 ) as claimed in claim 8 or 9, characterised in that the wire (2) is bent in the proximity of the soldering (3) in such a way to form a radial rod (11 ) that is connected with said axial rod (6).