EP2086427A1

EP2086427A1 - Distal locking system for intramedullary nails

Info

Publication number: EP2086427A1
Application number: EP06809151A
Authority: EP
Inventors: Giulio Cescutti
Original assignee: Cescutti Giulio
Current assignee: CESCUTTI, GIULIO
Priority date: 2006-10-31
Filing date: 2006-10-31
Publication date: 2009-08-12
Also published as: WO2008053264A1

Abstract

A system for the positioning and locking of intramedullary nails (2) includes a first supporting element (1) for supporting an handle (3) of an intramedullary nail (2), and is characterised in that said handle (3) further includes a slidingly fitted telescopic regulator (5), a supporting device (8) angularly and spatially adjustable with respect to said handle (3), a radial position adjustment device (9) fitted on the distal end of the supporting device (8), and a supporting block for an optical device (10) integrally arranged onto said radial adjustment device (9).

Description

DISTAL LOCKING SYSTEM FOR INTRAMEDULLARY NAILS

The present invention relates to a locking system for intramedullary nails and, more precisely, to a distal locking system for intramedullary nails for operations on long bones, such as tibia, femora, ulna, radius, and the like.

State of the art

It is known that the search for the correct fastening point of intramedullary nails in orthopaedic-trauma surgery is, and has always been, one of the most complex, delicate and risk-prone procedures, with possibly critical consequences both for the success of the fastening, and for the traumatic consequences on the patient's soft tissues.

Furthermore, during such procedures, there is a radiological examination of the correct position of the nails and, given the burden and length of the procedures required, the exposure time to dangerous ionising radiations for personnel and patients exceeds the limit allowed to prevent severe long-term consequences.

On the other hand, there are many already widely tested systems capable of finding the position of the intramedullary nail with a simple external mechanical guiding arm. In this way, the aforesaid problems become less important for the installation of very short nails (up to approximately 20 mm of length) because the flexural-torsional deformation to which they are subjected during introduction in the medullar channel is less important.

These positioning systems have not however solved the aforesaid problems in the use of longer nails (from over 20 to nearly 50 cm of length). Indeed, when introduced in the intramedullary channel, they may be subjected to local deformations of up to 1.5 cm at the coupling hole with the respective screw, with the natural consequence that there is no longer a correspondence between the hole itself and the external guiding systems. Furthermore, the devices with this function use the radiological apparatus for limited times. According to the previously known devices, either a supplementary hole of considerable diameter (8-9 mm) is made in the front region of the treated bone segment, or an alignment is created by means of external adjustable guiding arms, all under radiological examination. Summary

It is therefore the object of the present invention to solve the problems described above by providing a distal locking system for intramedullary nails aimed at and designed to identify and then correctly position the distal fastening screws of a respective intramedullary nail, without the use of radiological apparatuses, such as brilliance amplifiers and the like.

In particular, the system according to the present invention assists the surgeon and the surgical assistant in the use of intramedullary nails for the treatment of long bone fractures, such as femora, tibia and humerus. In such applications, distal fastening screws are used, where 'distal' means screws positioned in antithetical position with respect to the surgical access site.

According to the system of the present invention, all possible exposure time to ionising radiations is excluded, thanks to the use of an optical fibre calibration alignment device. This optical fibre device is of fundamental importance in order to limit all the pathologies which derive from the use of radiological apparatuses and which may effect both patients and personnel, including surgeons and paramedics responsible for surgical instruments and/or assistance in the operating theatre.

The previously known devices either exploit a supplementary hole of considerable diameter (8-9 mm) made in the front region of the treated bone segment, or create the alignment by means of external however adjustable guiding arms but only under radiological examination.

The exposure time represents a biological hazard higher than that of the system according to the present invention, which instead implies the positioning of an optical fibre or arthroscopic optics of maximum 4 mm in diameter and positioning it in lateral- medial direction in the femoral or humeral nails. Alternatively, the positioning of the optical fibre is provided in medium-lateral direction for tibia nails.

Detailed description of the invention A detailed description of a preferred embodiment of the distal locking system for intramedullary nails according to the present invention will now be provided, by way of non-limitative example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective, frontal view and side view of the positioning and locking system according to the present invention; Figure 2 is a perspective, frontal view and a view from another side of the locking system according to the present invention; figure 3 is a plan view from the top of the locking system according to the present invention; and figure 4 is a detailed view of the locking system according to the present invention and according to figure 1.

With reference now to the figures, the system of the present invention includes a first support 1 consisting of an instrumental pedestal for the external alignment of an intramedullary nail 2. On instrumental pedestal 1 is removably fitted a handle 3 which constitutes the supporting template for the later positioning of the intramedullary nail 2 in the patient. Handle 3 presents a guiding arm 4 adapted to slidingly support a telescopic distance adjustment body 5. Telescopic adjuster 5 includes a pair of guides 51 adapted to slide on guiding arm 4. Furthermore, a locking screw 6 is provided to lock the longitudinal running of said telescopic adjuster 5 on guiding arm 4.

Furthermore, a locking device 7 of adjuster body 5 consisting of a screw 70 fitted on band 71 is provided. Band 71 is tightened by the rotation of screw 70 thus locking the position of the adjustment body 5 on guiding arm 4.

A support device 8 for spatial angular orientation is arranged on the end of the telescopic adjuster body. Device 8 essentially consists of a double ball joint with screw for locking the respective rotations, so that by acting on the latter it is possible to lock/release the position of the device with respect to adjustment body 5.

On the distal end of supporting device 8 is fitted a radial position adjustment device 9 provided with a supporting seat block for an optical fibre device 10 (or alternatively for arthroscopic optics, or endoscopic optics of any kind).

Furthermore, adjustment device 9 fits a micrometric screw system 90 by means of which the displacement of optical fibre assembly 10 may be micrometrically adjusted with respect to the absolute horizontal and vertical direction (i.e. with respect to pedestal 1 ). On the other hand, again on device 9, are envisaged alignment guiding templates 11 of intramedullary nail 2, the length and diameter of templates 11 being chosen according to use. Furthermore, templates 11 may be threaded or not threaded. Moreover, liners and trocars may be provided for the sake of introduction of said optical assembly 10 and said templates, as well as supplementary guide masks. It must be specified here that respective guiding templates 12 of nail 2 are removably fitted on guiding arm 4 for the intrinsically known purpose similarly as described in relation to templates 11.

A detailed description of the application method of the positioning and locking device according to the present invention in a patient will now be provided.

The patient is firstly positioned as already known from conventional techniques for intramedullary nail application in relation to the treated bone segment. Surgical access is then performed in the conventional manner. A medullar channel is then prepared by boring or the like and, as contemplated by the conventional techniques in use, with the respective determination of the length of intramedullary nail 2 to be inserted, by means of the conventional techniques in use.

Nail 2 of predetermined length is then fixed to handle 3 and respective guide arm 4 of the device according to the present invention by means of connection screw (not shown in the drawings) and the system is positioned on support 1 for external alignment.

In this condition, telescopic distance adjuster 5 and spatial angular orientation support 8 are inserted on guiding arm 4. Then, after determining the position of the system, the latter is fixed in the determined position by means of the block of the telescopic distance regulator 5 and of the spatial angular orientation support 8. Then the system is disconnected from its external alignment support 1 and telescopic distance regulator 5 along with spatial angular orientation support 8 are released from the system, leaving the previously obtained alignment conditions unchanged while guiding arm 4 remains connected to intramedullary nail 2 by means of connection screw (not shown in the figure). In this condition, nail 2 is inserted inside the medullary channel.

Once nail 2 is inserted in the respective intramedullary channel, threaded templates 12 are positioned after being perforated with drills in the proximal part of the treated bone segment, and by means of respective guiding arm 4. System stability is increased in this way. Telescopic distance regulator 5 and spatial angular orientation support 8 are then re-inserted and the latter are locked to the same previously determined reference point.

Surgical access in the patient is made in this condition and on the bone distal part by micro-incision. Then, in the access made is inserted a liner and a hole is made by drilling in the cortical until either nail 2 or the middle of the medullar channel is reached. After perforating, the hole must be cleaned up using a cleaning brush of the alignment hole.

After cleaning the hole, optical fibre 10 (or arthroscopic optics) is inserted through a liner to reach the most reachable part of the nail. The insertion of optical fibre 10 in the hole and its connection to a monitor allows to identify the possible displacement endured by nail 2 during its insertion in the medullary channel.

After determining the exact position of nail 2 with respect to the intramedullary channel, optics 10 are extracted from the hole and radial correction is possibly performed by means of aforesaid spatial angular orientation support 8 in the measure determined by the observer on a monitor.

For example, if the hole of nail 2 is of a known diameter (e.g. 5 mm) and the view on the monitor identifies a position on the limit of the hole or at a peripheral part of the same, a correction of 2.5 mm will be required (i.e. the size of the radius) to return perfectly in axis with the hole itself. Then a second hole is made after performing the correction. At this point, threaded template 11 may be inserted to completely stabilise the system and start positioning the locking screws of nail 2 through the other holes of the spatial angular orientation support.

It must be mentioned here that in relation to the type of nail used, supplementary guides may be connected to find the orientation of the holes with different directions (not shown in the drawings).

Claims

1. A system for positioning and locking intramedullary nails (2) including a first supporting element (1) for supporting in a removable manner a supporting handle (3) of an intramedullary nail (2), characterised in that said handle (3) further includes:

- a guiding arm (4); a telescopic adjustment device (5) slidingly fitted onto said guiding arm (4);

- a locking device (7) for said adjustment device (5);

- a supporting device (8) being movable both angularly and spatially with respect to said handle (3), said supporting device (8) being arranged on the top end of the telescopic device (5); a radial position adjustment device (9) mounted on the distal end of said supporting device (8); and a supporting block for an optical device (10) integrally arranged onto said radial adjustment device (9).

2. A system for positioning and locking intramedullary nails (2) according to the preceding claim, wherein said optical assembly (10) is chosen from the group including: optical fibre; - arthroscopic optics; endoscopic optics.

3. A system for positioning and locking intramedullary nails (2) according to claim 1 or 2, wherein said adjustment device (9) further comprises a micrometric screw system (90) for micrometrically adjust the displacement of said optical fibre device (10) with respect to the absolute horizontal and vertical direction of said supporting element

⁽D-

4. A system for positioning and locking intramedullary nails (2) according to any of the preceding claims, wherein said device (9) further comprises at least one alignment guiding template (11) for said intramedullary nail (2).

5. A system for positioning and locking intramedullary nails (2) according to the preceding claim, wherein said at least one template (11) has a predetermined length and diameter according to its use, and may be either threaded or not threaded.

6. A system for positioning and locking intramedullary nails (2) according to any of the preceding claims, further comprising introducing liners and trocars for said optical assembly (10) and said templates (11).

7. A system for positioning and locking intramedullary nails (2) according to any of the preceding claims, further comprising guiding templates (12) of the nail (2) and removably fitted on said guiding arm (4).

8. A system for positioning and locking intramedullary nails (2) according to any of the preceding claims, wherein said telescopic regulator (5) further comprises: a pair of guides (51) mounted on a longitudinally sliding manner on said guiding arm (4); and locking means (6,7,70,71 ) for the locking of said telescopic regulator (5) in the longitudinal sliding direction with respect to said guiding arm (4).

9. An method for applying the positioning and locking system according to the preceding claims, characterised in that it comprises the following steps: positioning the patient for intramedullary nail application and in relation to the treated bone segment; performing a surgical access in the conventional manner; - preparing a medullary channel by boring or the like, and with respective determination of the length of the intramedullary nail (2) to be inserted;

- fastening the nail (2) of predetermined size on the handle (3) and respective guiding arm (4) of the system, and subsequent position on the support (1) for external alignment; - introducing the telescopic regulator (5) and support (8) on the guiding arm

(4); determining the position of the system and subsequent locking of the latter in position; disconnecting the system from the support (1 ) and releasing the telescopic regulator (5) along with the spatial and angular orientation support (8) from the system; introducing the nail (2) within the medullar channel;

- positioning the templates (12) at the treated bone segment and by means of the respective guiding arm (4); - re-introducing the telescopic distance regulator (5) and spatial and angular orientation support (8) and locking the latter to the previously determined reference point; performing a surgical access at the distal bone part by means of micro- incision; - introducing a liner in said access and perforation of the cortical to reach either said nail (2) or the middle of the medullar channel;

- introducing the optical assembly (10) through said hole to reach the most reachable part of the nail (2); - determining the eventual displacement of the nail (2) after introduction of the same in the medullar channel; and carrying out a radial correction by means of said spatial angular orientation support (8) by a value which is the measurement determined in the previous determination step.