WO2015140367A1

WO2015140367A1 - Endocavitary mechanical distractor device

Info

Publication number: WO2015140367A1
Application number: PCT/ES2015/000048
Authority: WO
Inventors: José Ignagio RODRíGUEZ GARCÍA; Pablo SUÁREZ MÉNDEZ; José Manuel SIERRA VELASCO
Original assignee: Universidad De Oviedo
Priority date: 2014-03-21
Filing date: 2015-03-20
Publication date: 2015-09-24
Also published as: ES2503891B2; ES2503891A1

Abstract

The invention relates to an endocavitary mechanical distractor device comprising a set of rigid and pivoting rods (6), a front head (1), an inlet port (3), transmission means (2), and actuating means (10). The particular configuration of the rods (6) is such that, once they have been rotated, a working space is created that can be accessed via the inlet port (3). The invention provides a device for providing assistance in surgical procedures, for medical exploration or for dosing medicines, that is particularly suitable for transanal endoscopic microsurgery (TEM) or urogynaecological treatments. The device can be employed in fields involved in the design, production and use of devices for surgery, medical exploration or dosing medicine, such as the technical field of human or animal medicine, that of machinery and mechanical equipment, or that of chemistry and pharmacy.

Description

ENDOCAVITARY MECHANICAL DISTRACTOR DEVICE

The present invention relates to an endocavitary mechanical actuator distractor device, formed by a system of pivoting rods, a head, an input port, transmission means for rotating the rods and actuation means that drive the transmission means. to unfold or retract the rods.

The invention provides a mechanical device that allows performing surgical procedures through natural orifices, such as Transanal Endoscopic Microsurgery (TEM), for medical examination, such as ultrasonography or gamma camera use, brachytherapy application, or dosing. of medications. The device has a configuration that makes it suitable for use in several access routes, such as in the mentioned TEM or in diagnostic or therapeutic explorations or procedures of the urogenital area.

The invention is therefore applicable in the sectors in which devices are designed, produced and used for surgery, medical examination, or other sanitary or drug dosing therapies, such as in the technical sector of human or animal medicine. , that of machinery and mechanical equipment or that of chemistry and pharmacy.

STATE OF THE TECHNIQUE

At present, most of the equipment and techniques used for exploration or surgery through natural orifices require the insufflation of C0 ₂ under pressure to achieve the expansion of the workspace. This facilitates the recognition of the area and allows the surgeon to work safely.

Among these techniques is, for example, Transanal Endoscopic Microsurgery (TEM), which is a transorificial procedure by which specific instruments - resection of large adenomas of the rectum and incipient cancers in the rectal bleb that is accessed from the anus is possible. The use of support instruments for this approach is widespread, which can be classified, depending on the materials used, such as rigid (made of steel or metal) or soft (made of plastic materials). In addition, this instrument can be reusable or disposable.

The pneumo-rectum under pressure is associated with gas filling of the proximal colon. Part of the gas is lost when suction is used to eliminate the washing liquids and small hemorrhages that occur during the operation, as well as the aspiration of the fumes produced by cauterizing wounds with an electric and ultrasonic scalpel. Having to wait to recover the pressure inside the rectum every time it becomes necessary to aspirate is a problem that lengthens the duration considerably and makes the intervention more difficult, since the continuous aspirations cause the rectal space to collapse. The pneumo-rectum requires general anesthesia and deep relaxation of the patient, which implies a series of inconveniences inherent to the anesthesia and the operation of the intervention, which partly depends on the tense state of the subject. The latter is especially relevant in fragile patients (elderly, with pluripatology, oncology ...).

There are several systems suitable for this type of microsurgery with pneumo-rectum, such as the equipment described in US Patent Application 1985/4538594 or European EP 2082682 (A2), which clearly indicates that the equipment has a tube through which an optician is inserted and which uses a pressure system and other accessories. It is common practice that these equipment also incorporate different accessories, such as optical or own instruments such as tweezers, scissors, scalpels, etc. which are now commonly used in operating rooms.

Another example is the patent applied for by the National Cancer Center (Boston, USA), of the year 2010, and with reference US 2010/0331620 (Al) entitled "Surgical apparatus for transanal microsurgery endoscope", where a rigid type equipment is described, characterized by the possibility of manual rotation of the endoscopic and instrumental tube that it carries to center the intervention area. Although these rigid type devices are suitable for the exploration of body cavities, they need a pressure system that allows the distension of the walls of the access duct to visualize the area to be treated and facilitate the access of the instruments for lighting, visualization ( for example with cameras) and the actual surgical procedure (using scalpels, scissors, tweezers, etc.).

Because, in general, commercial equipment is very expensive and also limits the use of medical equipment (only one that is compatible with a certain device and brand can be used), surgeons have provided other technical alternatives.

Thus, other devices previously used in the so-called single port laparoscopic surgery have been adapted to the anal opening and have developed specific soft-type equipment, also known as transorificial access ports. Commercially developed equipment of this type has the appropriate form to allow easy introduction by the natural route into the body and also incorporates different types of flexible ports with several holes for the introduction of the necessary instruments. As an example of this type of device, the one described in the patent application US 2013/0158354 (Al), entitled "Endoscopy instrument guide port", or the one in US20120095297 Al, entitled "Natural orifice surgery system" . As with rigid type equipment, in these technical alternatives there is still a need to insufflate gas inside the patient to allow a workload to be formed and, therefore, the problems inherent in the need for pressurization are maintained.

On other occasions, an elastic glove associated with some type of tube or accessory is simply used as a port that facilitates access to the interior of the subject or serves as a support for the instruments. For this, the glove opening is fixed around the port that is inserted into the patient's anus, thus achieving a tight seal. The fingers of the gloves are pierced so that one presses C0 ₂ under pressure to open the field of vision in the area to be treated, and through the other perforated fingers of the glove, using trocar shirts typical of the approach laparoscopic, the camera, the light source and the instruments necessary for the intervention are introduced.

As an alternative to the pressurization of the inner channel of the subject, there are other techniques of access to the body that propose using mechanical devices based on sheets or flexible cables, so that the flexibility of these elements is used to open the work field once You have accessed inside. In this way, the need to insufflate a fluid that provides expansion of the conduit to be treated can be dispensed with. However, based on flexible elements, the volume of work cannot be precisely controlled, and may even reach the local or complete collapse of the area to be treated and undesirable adverse effects. Within this type of apparatus, the one described in the patent application US 2007/0276189 (Al), based on a tube with two flexible side plates, can be mentioned, which by means of a retractable mechanism opens said sheets laterally to increase the working space. US Pat. No. 7390298 (B2) can also be cited as an example. This case is based on a mechanism that acts on a series of flexible cables, which can be stretched occupying little space to be introduced into the body by small holes or natural cavities, and once inside they expand thanks to its flexibility and a mechanism of drive

DESCRIPTION OF THE INVENTION

The present invention relates to a mechanical distracting device supporting surgical procedures, exploration or diagnostic-therapeutic procedures in which it is necessary to access the interior of the patient's body through a duct, and expand and maintain a workload in the cavity, which normally tends to collapse. Although the invention preferably relates to Transanal Endoscopic Microsurgery (TEM) procedures, the device can also be applied more generically to other types of interventions, such as for examinations or diagnostic-therapeutic procedures, or to other parts anatomical as the urogynecological area, with the appropriate modifications if necessary.

It is therefore an object of the present invention an endocavitary mechanical distracting device comprising: - A set of rigid and pivoting rods at its ends when transmission means are actuated. The rods have a curved and / or polygonal guideline, so that once pivoted they enable a free space as a work area within the patient's cavity.

In this way, the set of rods forms a means that expands the patient's duct, once the system has been introduced inside. In the moment before insertion, the rods are folded. When the system is introduced into the subject to the desired depth, the rods are pivoted by means of transmission. Because the guideline of the rods is not straight, their rotation expands the conduit in which they are located, enabling the workspace. Rigid rods can have different distribution, shape, eccentricity and length depending on the needs of the intervention to be performed (remove tumor, make hemostasis, suture, etc.). Preferably, for TEM procedures, it is desirable to obtain a diaphanous work space as a reference of about 5 to 6 cm in diameter and between 12 and 20 cm long in the patient's body. - A front head that houses one of the ends of the pivoting rods. This component, in addition to housing one of the ends of the rods, serves as a facilitating means of penetration. Preferably, this front head has a conical and rounded shape so that it facilitates the introduction and removal of the device in the patient. - An inlet port that houses the other end of the pivoting rods and comprising a hole for access to the inside of the cavity. The entrances to the patient's body, whether they are natural such as the anus or the vagina or are made surgically, tend to have irregular shapes. On the other hand, in the case of natural entrances, these are usually too small to be able to comfortably carry out treatments or observations. In addition, when bodies are introduced strangers in them there is a reflex act of closure, which in some cases can prevent any access until a new relaxation, voluntary or induced. The entrance port provides an access area inside the body with a fixed shape, maintaining a stable hole for the duration of the intervention. With the appropriate modifications, the input port can also have specific fixings for the instruments.

- A drive means of a transmission means. The drive means allow the activation of the device by its operator.

- Transmission means associated with one of the ends of the rigid and pivoting rods, which rotate the rods when actuating means are actuated. The transmission means translate the activation order into the effective rotation of the rigid rods.

In a preferred embodiment, the entrance port comprises holes that line the perimeter of the access hole to the cavity, to fix the entrance port to the patient's body. On some occasions, such as when the positioning of the instruments requires a stable base, the position of the input port must be ensured, preventing its relative movement with respect to the subject. These holes can be used for this purpose together with thread suture techniques or by using other fixing means, such as staples or screws. In another preferred embodiment, the input port is detachable from the rigid rods, and also attachable to them. This technical feature is useful in some of the device's applications. When the anatomy of the duct or the entrance hole to the patient's body is narrow or there is great resistance to distension, it is advisable that the foreign body that is introduced (in this case the device of the invention) be as compact as possible. In these cases, the head with the rods is first introduced, which makes the occupied volume small. Once inside, the input port or the other parts of the device are coupled, increasing the expansion of the conduit and / or the entrance. Finally the rods are pivoted, enabling the definitive workspace. The above sequence is simply a example. The coupling or decoupling does not have to be done in any pre-established order, being normally at the discretion of the device operator.

In a more preferred embodiment that would allow the previous feature to materialize, the inlet port has pressure fittings radially arranged on its inner face, to fix the ends of the rods before or after they have been deployed inside the patient , and thus allow the necessary accessories (camera-point of light, surgical instruments, etc.) to pass inside. In another preferred embodiment, the inlet port may not have the fittings for fixing the ends of the rods on its inner face, but simply have grooves on its outer face.

In another preferred embodiment, the transmission means are housed in the front head.

In another preferred embodiment, the transmission means are housed in the input port. In this type of embodiment, the front head can be of smaller size (length and diameter), allowing to take advantage of the space and its configuration to easily become an exploration camera holder, surgical tool holders or medication dosing holder. In a more preferred embodiment, the transmission means are decoupled from the input port or attachable to it. In this way the use of the apparatus is facilitated, using certain components only when they are necessary for a function, and clearing the entrance and the hole for access to the interior of the cavity.

In a specific embodiment, the drive means of the transmission means comprise:

- A transmission shaft that transmits a pair to the transmission means to pivot the set of rigid and pivoting rods.

- A jacket in which the transmission shaft is housed and which is integral with the head and / or the input port. The jacket, when attached to the head and / or the input port, allows the rotation of the drive shaft while preventing uncontrolled torsion of the assembly when the rods are deployed, providing a fulcrum. In a more specific embodiment, the drive means are decoupled or attachable to the rest of the device. Similar to previous cases, this allows the work space inside the visor and access to be released once the drive means have fulfilled their function. Thus, for example, the jacket in which the transmission shaft is housed can be coupled or uncoupled, ensuring the solidarity of the assembly by means of a removable threaded joint.

In another more specific embodiment, the drive means further comprise a knob associated with the drive shaft, which can be manually manipulated. In this case, the torque that is transmitted to the rods and that cause their rotation may have their origin in the user's own manual action of the device. Although its origin may be other motor means, such as electric motors, hydraulic or pneumatic drives, etc., in procedures such as TEM it is common for instruments to be controlled manually by the surgeon.

In another specific embodiment, the transmission means comprise: - A driving or driving gear that transmits a pair to driven gears.

- Some gears driven integral to one of the ends of the rigid and pivoting rods.

In a more specific embodiment, the driven gears are radially meshed around the driving gear. Although several configurations can be established, all of them functional, preferably the arrangement of the transmission means is such that the driving gear is located in the center and is radially surrounded by the driven gears, which are engaged therein. In this way, the driving gear can be referred to as "planet" gear and the gears driven "satellite" gears. The "satellite" gears, one per rod, are each fixed to one end of each rod, and are simultaneously driven by a "planet" gear, thus facilitating the rotation of the rods. In one of the configurations, the torque that causes the movement of the "planet" gear reaches it through the drive shaft of the drive means, which can be coupled or uncoupled as required by the user. In another specific embodiment, the device further comprises flexible anti-collapse elements that perimetrically connect the pivoting rods. In this way, the flexible anti-collapse elements act as a screen to keep the walls (intestinal, vaginal, etc.) between rods, away from the work area. This type of embodiment is advisable when the rods, once turned, are very separated or when the duct offers great resistance to opening, such as the rectal tract or the vagina.

In a more specific embodiment, the anti-collapse elements are threads. In another more specific embodiment, the anti-collapse elements are a network. In another more specific embodiment, the anti-collapse elements are bands or sheets.

One way of materializing the above specific embodiments is, for example, by means of transverse holes in the rods, through which the flexible anti-collapse elements (threads, elastic bands or others) can be placed.

A very important aspect of the invention is the fact that when opening the necessary work space for surgical interventions or explorations based on a mechanical system, it is not necessary to insufflate C0 ₂ (or other gas) under pressure, and avoid disadvantages of this technique due to the loss of pressure, which hinders and delays interventions.

Unlike gas interventions (with pneumo-rectum under pressure), interventions using the device of the invention can be done without the need for general anesthesia and deep relaxation of the patient. The possibility therefore opens up of using less aggressive or dangerous intervention methods for the patient, such as with spinal anesthesia.

The device object of the invention also provides an expanded and stable working area during the entire period of time that the intervention lasts, due to the rigidity of the folding rods. These elements constitute a stable screening structure against the natural tendency of collapse of patient access roads. In addition, the deployment position of the rods can be maintained over time by interlocking the transmission means, if necessary. On the other hand, the use of gears as means of Transmission, as described in one of the embodiments of the invention, allows a very high level of precision and repeatability, which results in safer interventions.

The folded rods, once turned, are responsible for providing the necessary work space for a safe intervention. These elements can be manufactured in different shapes and sizes, so that they can adapt both the length and the diameter of the device (both the minimum, with the rods folded to be introduced or removed from the patient's body, • as the maximum, which defines the workspace once expanded). Because they can be materialized in several ways, they can be adapted to specific procedures, such as scans, sutures, etc.

In one of the embodiments of the device, transmission means by gears, drive means by means of a transmitter shaft and a knob for manual manipulation are described. By the type of manual drive, based on a mechanical system of simple and robust design, this embodiment assumes a very reliable and safe device.

The invention provides a device that, in addition to allowing the performance of surgery procedures, also provides a means for medical examination activities, medication dosing or other health therapies. Specifically, the invention is applicable in Transanal Endoscopic Microsurgery (TEM) procedures, but it also has a configuration that would make it suitable for other access routes, specifically in explorations or urogynecological surgeries.

The invention is therefore applicable in the sectors in which devices are designed, produced and used for surgery, medical exploration, other sanitary or drug dosing therapies, such as in the technical sector of human or animal medicine, that of machinery and mechanical equipment or that of chemistry and pharmacy. DESCRIPTION OF THE FIGURES

Fig. 1 shows a perspective view of the system, with the rods (6) in the retracted position.

Fig. 2 shows a perspective view of the system with the rods (6) in the deployed position.

Both the Fig. 1 and Fig. 2 show the same preferred embodiment of the device, which comprises several parts.

Head (1). Basically it is a piece that acts as a plug or closure for the transmission means (2) that are housed inside and that rotate the rods (6) with respect to their own axes. The head (1) has a rounded outer shape that facilitates the introduction and removal of the device in the patient. It could be of a metallic material (and therefore reusable), or of a disposable plastic material.

Transmission media (2). Housed in a cylindrical part (carrier), with through holes through which the rods (6) are introduced. The ends of these rods (6), in this preferred embodiment, are connected to driven gears (8) or "satellites", which are actuated for rotation through another driving gear (7) or central "planet", which Gear simultaneously with all driven gears (8) or "satellites" of the rods (6). The transmission means (2) in these figures are hidden, covered by the carrier and the head itself (1).

Port of entry (3). It is a cylindrical piece at the back to which all the rods (6) are attached. Once the device is inserted inside the patient, through the hole for access to the inside of the body cavity there is access to introduce other elements, such as actuation means (10) or the equipment to be used in surgical interventions (tweezers , scalpel, optics, cameras, scissors, ...).

Drive means (10). In the preferred embodiment shown in these figures, they are composed of a jacket (4) that houses a drive shaft (5) and a knob (9). In these figures, the jacket (4) that is represented is a complex and removable piece, composed of a tube with an outer thread in the front. In this way, the jacket (4) can be attached to the carrier, keeping the position of the latter and the head (1) fixed, while allowing the relative rotation of the transmission shaft (5) that passes through its inside and induces the rotation of the driving gear (7) or central "planet". The shirt is equipped with a handle with a knurled back that facilitates the grip of the set during its operation. The drive means (10) also have a knob (9) on the back, which facilitates the fastening of the whole assembly both for its introduction, and for expanding or retracting the rods (6).

The drive shaft (5) is a straight rod. One way to realize it is with a screwdriver-shaped head (flat or star), which is connected to a compatible head located on the driving gear shaft (7) or "planet." When the drive shaft (5) is rotated, it transmits the torque to the driving gear (7) or "planet" so that the rods can be expanded or retracted on themselves.

The knob (9) is located at one end of the drive means (10). This piece facilitates the rotation of the tool, as well as its introduction and removal.

Rods (6). They are curved shaped pieces. Its initial and final ends are aligned and straight, and have the central zone folded with a certain eccentricity. This eccentricity defines the free volume as a working area within the patient's cavity.

The shape of the fold, the angular distance between rods (6) and even the number of rods (6) could vary depending on the type of intervention to be carried out (remove a tumor, suture, perform scans with ultrasound devices , device probes for isotope identification, introduction of seeds for brachytherapy or others).

The rods (6) have spaced cross holes to accommodate flexible anti-collapse elements that perimetrically connect the rods (6). In these figures these elements are not represented. The holes allow the use of an anti-collapse element in the form of a wire, which can be mounted on site, even by means of suture thread, and that allows the rods (6) to be joined transversely to each other, so that when they expand inside the intestine they serve as a screen or net to keep the work area free.

A front view of the device without the head (1) is shown in Fig. 3. In it you can see a materialization of the transmission means (2), based on a gear mechanism that allows the simultaneous rotation of all the rods (6). One end of each rod (6) is fixed to a driven gear (8) or "satellite" gear. These "satellite" gears are in contact with a conductive gear (7) or "planet" gear which, when turned, drives the "satellite" gears that in turn rotate the rods (6), unfolding or folding them according to the direction of turn. The entire assembly is covered by the head (1) so that the driving gear (7) or "planet" rotates around an axis between the head (1) and the drive carrier, as well as the driven gears ( 8) or "satellites". The driving gear (7) or "planet" is in turn coupled to the drive shaft (5) of the drive means (10).

In Fig. 4 the system can be seen in its two positions: folded and unfolded. In the retracted position, the outer diameter of the set D is determined by the diameter of the head (1). In the deployed position, the outer diameter of the assembly W is greater than D, and is determined by the space occupied by the deployed rods (6).

Preferably for TEM interventions, the diameter D is less than 3.5 cm, which facilitates the introduction or removal of the device in the patient's body. In the deployed position, the outer diameter W can reach 5 or 6 cm. The lengths of the head (1) A and the inlet port (3) C are fixed, and the length of the rods (6) L can be adapted to the patient's size and tumor situation, varying between about 10 to 25 cm, if They could well be manufactured to any size.

The rear view of the device is shown in Fig. 5, when the rods (6) have been deployed in the working position, and with the rods (6) embedded in the inner perimeter of the input port (3). In the background you can see a carrier that houses the transmission means (2), leaving a head in sight in the form of a star or cross located on the axis of the driving gear (7) or "planet" to which the transmission shaft (5) can be attached. In this figure, the drive means (10) are decoupled, leaving access to the interior of the cavity free. In Fig. 6 and in Fig. 7 a variant of the device is shown that allows to place uncoupling transmission means (2) in the rear part of the system, coupled in the input port (3). In this way, the transmission means (2) remain outside the patient's body, and the front of the device or head (1) is also left free.

EXPLANATION OF A PREFERRED EMBODIMENT

For a better understanding of the present invention, the following examples of preferred embodiment are described, described in detail, which should be understood without limitation of the scope of the invention. One of the main characteristics that was desired to achieve with the described device was its functionality, based on a simple use, together with the constructive and operating robustness. Therefore, several prototypes were manufactured using the techniques and materials detailed below.

The prototypes were built on the same base design, with small changes in the materials used, the dimensions of parts of the invention, the manufacturing processes or the arrangement of the components.

EXAMPLE 1

The device described here was a mechanical system that, in folded or collected position, had an approximate outer diameter of 3 to 3.5 cm and with a rounded conical head (1), which facilitated that it could be introduced into the body of the patient by a natural route (anus or vagina). Once inside the body, by means of a manually operated mechanism, some rods (6) that rotated with respect to their straight and aligned ends were expanded or deployed, leaving free within the patient's body a workspace, approximately cylindrical, with a diameter of between 5 and 6 cm and a length of 8 cm.

In these prototypes, the transmission means (2) materialized in gears: a driving gear (7) or "planet" and five driven gears (8) or "satellites", each of them fixed to the end of one of the rods (6). The drive means (10) consisted of two parts: a jacket (4) and a drive shaft (5). The drive shaft (5) had a star-shaped or double-spindle machining at the end, which in turn acted directly on a compatible head on the driving gear shaft (7) or "planet" for the rotation of the rods. (6), thus allowing to deploy or retract these. To facilitate rotation, the drive shaft (5) ended at the end that was outside the distractor in a T-shaped knob (9).

In this preferred embodiment, one end of the rods (6) was introduced into a piece called the actuator holder, through a hole therein in which it rotated, by means of a friction bushing, the end of the rod (6). Inside the drive carrier, the rod (6) was rigidly attached to a driven gear (8) called "satellite", with one for each rod (6). The opposite end of the rods (6) was free, and once inside the patient's body and expanded the rods (6) to the working position, this free end that was still outside the patient's body was coupled by pressure to the piece called input port (3). The coupling was made on the outer perimeter of the inlet port (3), thus leaving the hole for access to the interior of the cavity disposed in the inner part of the inlet port (3) free. This hole had an approximate diameter of 3 to 3.5 cm, and allowed the passage of support instruments in endo or microsurgery interventions. In this preferred embodiment the transmission means (2), responsible for transmitting a torque for the rotation of the rods (6) with respect to their axes, were composed of six gears: five driven gears (8), called "satellites", around of a driving gear (7) "planet." The five driven gears (8) "satellites" (one for each rod carried by the distractor) were arranged radially inside a cylindrical part called a carrier, with the axes of the rods (6) and the driven gears (8) "satellites" located in the same circle. The "satellites" gears were equal to each other (same module, number of teeth and primitive diameters), and simultaneously geared with a "planet" driving gear (7) located in the center of the drive-holder part and the circumference. The driving gear shaft (7) "planet" rested on the one hand on the inside of the front head (1), and on the other hand on the center of the drive carrier. The axis of this driving gear (7) "planet" had grooves in the front, so that it could be operated using coupling drive means (10) comprising a transmission shaft (5) with its machined head in the form of star or double planillo.

In this preferred embodiment, the drive means (10) were manual, and were formed by a drive shaft (5), a jacket (4) and a knob (9) at the end of the drive shaft.

The shirt (4) was manufactured from a round tube with a threaded end, while a knurled handle was inserted in the other that facilitated the grip. The threaded end was inserted into the drive holder before inserting the device into the body cavity. With the rods (6) in the stowed position, the device was introduced, placed and oriented by manipulating it with the shirt handle (4). Once in position, the drive shaft (5) was inserted into the jacket (4). This drive shaft (5) had at one of its ends a drive knob (9) and on the other a star-shaped or double planar machining. When introduced through the jacket (4), it fit the corresponding star or groove shape in the shaft in which the driving gear (7) or "planet" was cut. By manually turning the drive knob (9) located at the end of the drive shaft (5), the movement was transmitted to the driving gear (7) or "planet", which in turn, and being simultaneously engaged with the five gears conducted (8) or "satellites", fixed to the rods (6), caused the latter to rotate in the desired direction, deploying or retracting them as interested. The device and its components can be manufactured with metallic materials (stainless steel, aluminum, etc.) and non-metallic materials (plastics, ABS, carbon fiber, etc.), which allows the whole set or parts of the system to be disposable or to undergo sterilization treatments to be reused.

Materializing the different components with the characteristics as described above, two prototypes were constructed with the processes and materials indicated below.

Prototype 1

• The front head (1), the input port (3), the driving gear (7) "planet" and the driven gears (8) "satellites", in addition to the knob (9), were made of ABS plastic. All the pieces were produced by additive manufacturing techniques using a 3D printer, which allowed to obtain pieces with adequate strength.

• The rods (6) and the drive shaft (5) were made of AISI 316 stainless steel.

• The jacket (4) was made of an aluminum tube, with one end attached to a hollow threaded piece of aluminum, which was used to fix the jacket (4) to the drive-holder piece. A suitable glue was used for the materials to be joined, bi-component with high temperature resistance, so as to allow sterilization treatments.

To sterilize the prototype (as would be done in a real surgical procedure), an autoclave (5 min at 134 ° C) was used in which the metal components and also the head (1) were treated as a sample. On the other hand, a peroxide-based sterilization method for plastic parts was also tested.

The functional tests allowed, on the one hand, to validate the design in terms of main dimensions, constructive form and arrangement of all the elements. On the other hand, the sterilization process carried out by the two usual methods concluded the need to replace the bond with glue with a rigid joint. The plastic used in the prototyped pieces allowed them to be sterilized with peroxide, although they lost color but not their mechanical properties Nor its functionality. The autoclave sterilization did not present problems in metal parts, although it affected the glues and the prototyping parts in ABS.

From the conclusions of this first prototype tested on a mixed simulator, a second prototype was proposed.

Prototype 2

The materials used were now.

• Two metal versions were manufactured from the front head (1): one in aluminum and one in stainless steel.

• The driving gear (7) "planet" and the driven gears (8) "satellites" were acquired from a commercial brand in stainless steel material (AISI 316).

• The knob (9) was made of ABS plastic, obtained through additive manufacturing techniques.

The rods (6) and the drive shaft (5) were made of stainless steel (AISI 316).

• The jacket (4) was made of an aluminum tube, with one end with a thread compatible with a threaded joint to fix the jacket (4) to the drive-holder part.

To sterilize the equipment (as it would be done in a real surgical procedure), the same autoclave (5 min at 134 ° C) was used for the metal components and peroxide for the parts in ABS.

This last prototype was also tested on mixed simulators with animal visors and also on a corpse. The results of the tests were fully satisfactory, confirming their capacity as an alternative to the technologies known in the state of the art. From the functional tests, the possibility of materializing different sets of rods (6) of different lengths and even shapes to adapt the device to different work areas was concluded.

EXAMPLE 2

Looking for new functionalities, a third prototype was manufactured, which now incorporated the transmission means (2) not housed in the front head (1), but were coupled at the rear, in the input port (3). This allows to leave the front head (1) free, so that it can be used as an instrument holder, for a video camera, light source, medication dispenser or simply hollow with free access for observation or treatment of the area.

This variant was mainly characterized by the fact that the transmission means (2) were outside the patient's body. The transmission means (2) were coupled and decoupled to the rods (6) by the back of the device, once the rods (6) exceeded the inlet port (3) outwards.

Claims

1. Mechanical endocavitary distractor device comprising:

- a set of rigid and pivoting rods (6) at their ends when transmission means (2) are operated, with the initial and final ends aligned, and of curved and / or polygonal guideline, so that, once pivoted they enable a free space as a work area within the patient's cavity;

- a front head (1) housing one of the ends of the pivoting rods (6);

- an inlet port (3) housing the other end of the pivoting rods (6) and comprising a hole for access to the inside of the cavity;

- drive means (10) of transmission means (2);

- transmission means (2) associated with one of the ends of the rigid and pivoting rods (6), which rotate the rods (6) when operating on actuating means (10).

2. Device according to claim 1 characterized in that the inlet port (3) comprises holes that border the hole for access to the interior of the cavity, to fix the inlet port (3) to the patient's body.

3. Device according to claim 1 characterized in that the input port (3) is detachable from the pivoting rods (6).

Device according to claim 1 characterized in that the transmission means (2) are housed in the front head (1).

5. Device according to claim 1 characterized in that the transmission means (2) are housed in the input port (3).

Device according to claim 5 characterized in that the transmission means (2) are decoupled from the input port (3).

7. Device according to claim 1 characterized in that the drive means (10) comprise:

- a transmission shaft (5) that transmits a pair to the transmission means (2) to rotate the set of rigid and pivoting rods (6); - a jacket (4) that houses the drive shaft (5) and that is integral with the head

(1) and / or to the port of entry (3).

Device according to claim 1 or 7, characterized in that the actuating means (10) are decoupled.

Device according to claim 7, characterized in that the drive means (10) further comprise a knob (9) associated with the manually manipulable transmission shaft (5).

Device according to claim 1 or 7, characterized in that the transmission means (2) comprise:

- a driving gear (7) that transmits a pair and drives driven gears (8);

- driven gears (8) associated to the driving gear (7) and integral to one of the ends of the rigid and pivoting rods (6).

11. Device according to claim 10 characterized in that the driven gears (8) "satellites" are radially meshed around the driving gear (7) "planet".

12. Device according to claim 1 characterized in that it further comprises flexible anti-collapse elements that perimetrically connect the pivoting rods (6).

13. Device according to claim 11 characterized in that the anti-collapse elements are threads.

14. Device according to claim 11 characterized in that the anti-collapse elements are a network.

15. Device according to claim 11 characterized in that the anti-collapse elements are bands.