Abstract: An inflatable balloon cuff may be adapted to seal a patient's trachea when associated with an endotracheal tube. These cuffs may include indicia that facilitate attachment of the cuff relative to the tube to reduce manufacturing variability for such characteristics as rotational and length alignment. Such indicia may include protrusions that are formed in the wall of the cuff collars or may include visual indicators, e.g., colorimetric or shape-wise indicators. Cuffs with improved attachment relative to the tube may have increased sealing performance.

Abstract: Disclosed is a respiration-assisting tube whereby tissue damages in vivo can be prevented and, as a result, inflammatory reactions and infections can be avoided. The respiration-assisting tube is developed based on the finding that adhesion of cells to a respiration-assisting tube can be inhibited by coating the respiration-assisting tube with a polymer containing 2-methacryloyloxyethyl phosphorylcholine (MPC). Also, the respiration-assisting tube is developed based on the finding that, by coating a respiration-assisting tube with a polymer containing MPC, mucosa peeling and tissue damages, which occur after using the respiration-assisting tube, can be prevented and, as a result, inflammatory reactions can be avoided.

Abstract: The present invention provides various systems, a kit, and a method for accessing, sampling within, and visualization of areas within the mediastinal cavity for assisting a surgeon in performing a mediastinoscopy procedure. The access system includes one or more preferably toroidal balloons that can be expanded to dilate and protect the inner walls of a bodily conduit. Instruments pass through hollow spaces within the expanded toroidal balloons. The proximally positioned balloons are expanded first and the unexpanded balloons to be positioned distally are passed through them and subsequently expanded. The sampling system includes an instrument with a rounded head having two or more jaws and a slit therein at the distal end of an elongated tubular body. The visualization system includes a 360° camera that can be positioned from proximal to distal a target site and can also do a U-turn about its axis of extension.

Abstract: A tracheal tube system includes a conduit and an inflatable cuff disposed on the conduit that seals a patient's airway. The tracheal tube system also includes an inflation line disposed along a portion of a length of the conduit and terminating in an opening within the inflatable cuff. The tracheal tube system further includes a speaking valve disposed at a proximal end of the conduit and in fluid communication with the inflatable cuff. The speaking valve is fluidly coupled to the inflatable cuff via a one-way valve such that fluid from the cuff flows into the speaking valve when the one-way valve is open.

Abstract: A molded tracheostomy tube may provide enhanced comfort for a patient. A unitary molded coating over areas of the tracheostomy tube that come into contact with the patient's skin may prevent irritation. Further, the overmolding manufacturing process may allow the tracheostomy tube assembly to incorporate features that allow for greater ease of movement for a patient, such as features that allow flexing at the connection point of the tracheostomy tube to other medical devices.

Abstract: A tracheal tube system includes a tracheal tube assembly having a cannula configured to be positioned in a patient airway, and a connector coupled to the proximal end of the cannula. The tracheal tube assembly further includes a cuff disposed about the cannula. The tracheal tube system additionally includes a speaking valve comprising means for deflating the cuff, wherein the speaking valve, the connector, and the cannula form a contiguous passageway for delivering air one-way into the patient airway when the speaking valve is disposed onto the end connector.

Abstract: The present application relates to endotracheal tubes and to systems and methods for detecting airway edema and evaluating breathing with an endotracheal tube

Abstract: A flexible expandable inter vivos tube includes at least one arched segmented portion, a corresponding movable element and at least one positioning mechanism. The at least one arched segmented portion and corresponding movable element forming a flexible closed longitudinally expandable tube. The at least one arched segment includes an H-shaped connector having at least one cavity that allows variable slidable movement of a free end portion of the corresponding movable element. A balloon is contained in each of the at least one cavity so that the hydraulic or air pressure within balloon expands the movable element and, thus, the circumference of the flexible inter vivos tube is increased.

Abstract: An airway device includes an airway tube having a first end surrounded by a laryngeal cuff which includes a back dorsal portion, a front face portion and a tip portion. The front face portion is shaped to form an anatomical fit over the laryngeal inlet of a patient, and to form a seal with the laryngeal inlet of the patient. The tip portion includes an annular sealing bulge which is adapted to wedge into an upper oesophagus region of the patient. The annular sealing bulge improves sealing of the tip of the laryngeal cuff in the upper oesophageal region of the patient. The annular sealing bulge is preferably formed from a soft polymeric or other plastics material with a Shore hardness of between 40 and 000 on the A scale, and allows for better sealing with a more variable range of upper oesophageal anatomical features.

Abstract: A device for dilating an opening through the tracheal wall of a patient includes a loading dilator. A balloon catheter is received in the lumen of the dilator such that the balloon extends distal to the loading dilator distal end. The balloon is configured to radially dilate a portion of the tracheal wall upon inflation. The balloon includes retention structure along its outer surface such that upon inflation, the retention structure inhibits dislodgement of the balloon when the balloon is positioned across the tracheal wall. The retention structure may comprise a pair of spaced elements radially projecting from the outer surface of the balloon, and spaced along the outer surface such that each of the elements is disposed at an opposite side of the tracheal wall when the balloon is positioned along the tracheal wall opening.

Abstract: A cuff for placement on the outside surface of a first tube, for example, a tracheostomy or endotracheal tube, and a method of making the cuff. A pattern of the cuff including first and second end regions by which the cuff is to be attached to the first tube is RF welded onto second tube of a thin pliable RF weldable polymer. Polymer material outside the pattern is removed, leaving the length of the cuff including the first and second end regions. The length of the cuff including the first and second end regions is turned inside out to place the cut edge of the weld of the RF welded seam on the inside. The first end region is slipped onto an end of the first tube. The first end region is turned inside out again to orient the cut edge of the weld of the RF welded seam away from the first tube. The first end region is attached to the first tube.

Abstract: An improved method for securing a tracheal tube, an adjunct tube, and oropharyngeal tube, a nasogastric tube, a laryngeal tube or laryngeal mask airway to a patient utilizing an elongated strip of adhesive tape, which is specifically adapted therefor.

Abstract: The present disclosure describes systems and methods having a dual-lumen tube with an assembly end. The assembly end may be molded and coupled to an extruded portion of the tube to form a complete dual-lumen tube. The assembly end may form the distal portion of the dual-lumen tube, which may simplify the manufacturing process by eliminating cutting and shaping steps involved in forming the distal ends of the ventilation lumens. The assembly end may be molded or otherwise formed so that the distal portion is not cut to length. In addition, the assembly end may include addition functionality, such as a camera apparatus or one or more sensors.

Abstract: A laryngeal mask airway device for insertion into a patient to provide an airway passage to the patient's glottic opening. The device includes an airway tube, a mask attached to the airway tube, a peripheral inflatable cuff, and an outlet for gas. The mask is attached to the airway tube for gaseous communication between the tube and an outlet. The device further includes an oesophageal drain that includes a conduit that extends from an inlet at the distal end of the mask to an outlet disposed outside the patient when the device is in place. The conduit includes a mask section and airway tube section, wherein the mask section is formed integrally in the material of the body of the mask.

Abstract: An airway device for human or animal use comprising an airway tube having a distal end and a proximal end, the distal end of which is surrounded by a laryngeal cuff, adapted to fit anatomically over the laryngeal structure of a patient, wherein the device optionally further comprises a buccal cavity stabiliser located on or around the airway tube between the laryngeal cuff and the proximal end of the tube, said buccal cavity stabiliser being adapted to nest with the anterior aspect of the patient's tongue, the size, shape and configuration of the buccal stabiliser being adapted to prevent rotational or side-to-side movement of the airway device in use.

Abstract: A method and system for increasing the flow resistance of collateral pathways in the lung by employing aspiration to establish an artificial convective flow current between compartments in the lung in order to entrain and deliver a clogging agent preferentially to the collateral pathways. The method may sometimes be performed after lung has been assessed for the presence of collateral pathways.

Abstract: A lung ventilation device has a stem to fit in a trachea, having at least two ventilation passageways communicating with distal passageways configured to fit in the bronchi at the carina. There is a positioning balloon to engage the walls at the carina when inflated. The positioning balloon has a proximal annular portion surrounding a distal end of the stem, and a plurality of annular distal portions, each surrounding a distal passageway end. The distal balloon portions are extensions of the proximal balloon portion. There may be a frangible link between the distal passageways, to break to separate the distal passageways in situ for bronchi entry as the positioning balloon is inflated. There may be stylets extending along the stem and arranged to provide stiffness to the distal passageways during device advancement in the trachea.

Abstract: The present invention is directed to a novel device and method for providing a disposable endotracheal intubation device for use with an auxiliary passageway serving as a guide for the placement of an orogastric or other enterally directed device in a patient. The present invention pertains to a medical catheter device, removably attachable to an endotracheal tube, for guiding the path of an enteral tube into the esophagus of a patient. The catheter device preferably employs an adjustable clamp to fix the position of the catheter relative to the endotracheal tube. The present invention also pertains to a combination medical intubation device comprising an endotracheal tube and a catheter proximate the endotracheal tube to guide the path of an enteral tube. The present invention also pertains to a method of intubating a patient using this combination medical intubation device.

Abstract: The invention relates to a laryngeal mask airway device (1) for insertion into patient to provide an airway passage to the patient's glottic opening, the device (1) including an airway tube (2), a mask (3) attached to the airway tube (2), the mask (3) including a body (4) having a distal end (5) and a proximal end (6), a peripheral inflatable cuff (7), and an outlet (8), the mask (3) being attached to the airway tube (2) for gaseous communication between the tube (2) and the outlet (8), the device (1) further including a structure to prevent occlusion of the outlet (8) by the patient's anatomy, the structure including a support (11), and a conduit (28a) to allow gas to flow out of the outlet (8), past the support.

Abstract: An orotracheal intubation device (1) for intermittent low-pressure ventilation of a patient provided with an inflatable cuff (3) including two lines of holes (2,5) communicating with the inflatable cuff and a one-way round valve (4) preventing air flow during inspiration and allowing air flow during expiration.

Abstract: The preferred embodiments provide, e.g., a high quality flexible tracheostomy tube assembly including an outer tracheostomy cannula and a disposable, flexible inner cannula. In preferred embodiments, the product provides a single patient use, sterile device.

Abstract: According to various embodiments, a tracheal tube may include a pressure monitoring lumen configured to provide information related to the pressure in the tracheal space. By measuring pressure in the lumen, a tracheal pressure may be estimated. The pressure monitoring lumen may be in fluid communication with a pressure transducer that provides pressure measurements. An opening of the lumen may be covered with a distal shoulder of an inflatable cuff.

Abstract: A system and accompanying assembly, of integrated or modular construction, for inflating and monitoring pressure within a retaining cuff including a housing having a pressure chamber connected in fluid communication with a fluid pressure source and a fluid communicating connection with the retaining cuff. Associated control circuitry includes a pressure sensor disposable in fluid communication with the pressure chamber and the retaining cuff, via the fluid communicating connection and structured to concurrently determine and monitor pressure within the pressure chamber and the retaining cuff. The control circuitry is cooperatively structured with the pressure sensor and other operative components to establish dynamic multilevel sampling capabilities, calibration parameters stored within the control circuitry prior to use and limited or single use capabilities of the assembly.

Abstract: According to various embodiments, methods and systems for determining pressure in an inflatable cuff of a tracheal tube may employ pressure transducers associated with a cuff inflation line. The pressure transducers may be implemented to provide continuous or intermittent cuff pressure. Also provided are inflation assemblies or other devices that incorporate pressure transducers. The inflation assemblies may be coupled to the tracheal tubes via the inflation line.

Abstract: A multi-lumen breathing tube device providing for separate and bidirectional gas flow for expired and inspired gas during ventilation of a lung. Embodiments of the multi-lumen breathing tube include an improved laryngeal mask airway device and an improved endotracheal tube. The invention is compatible with a circle breathing circuit system used with many mechanical ventilators including those used in conjunction with anesthesia machines.

Abstract: A probe for medical use comprising a tube (1) and a cuff (3) located around the tube (1) in a region of its external wall, the cuff (3) being inflatable through a conduit (5) arranged at the wall of the tube (1), linking the interior of the tube (1) to the interior of the cuff (3), the inflation and deflation of the cuff (3) being determined by the rhythms of the inspiration and expiration of air, respectively.

Abstract: Pressure indicator comprising a base, a deformable membrane fixed to the base in a fluid-tight manner according to a closed contour, and a body fixed to the base, delimiting a hollow volume covering the deformable membrane on the side opposite the base, while encompassing at least the closed contour, at least one inlet for a fluid the pressure of which is to be measured in a pressure range, wherein the deformable membrane is such that the expansion thereof for said pressure range is sufficient to be visible to the naked eye and to allow a direct display indicative of the pressure, in that the base is drilled with at least one first hole a first end of which emerges between the deformable membrane and the base in the closed contour, in that the body is drilled with at least one second hole a first end of which emerges into said hollow volume, in that the other end of the first hole is linked to the inlet respectively to the open air, in that the other end of the second hole is linked to the open air, respectiv

Abstract: A breath intake valve is connected to a tracheostomy tube inserted into a patient's trachea. The inner end of the valve attaches to the tracheostomy tube. An apertured disk endpiece with an O-ring around its circumference is releasably set into the outer end of the tubular valve body. A floppy diaphragm overlying the inner face of the disk endpiece functions as an intake valve to allow patient inhalation and air intake, and as a check valve to block patient exhalation, thereby to redirect it to the patient's larynx, sinuses, and mouth for normal speech. The O-ring gives way to forceful patient exhalation to release the disk endpiece from the tubular valve body. The disk endpiece is tethered to the breath intake valve body to prevent misplacement of the endpiece after such a release. The breath intake valve is itself likewise tethered to the tracheostomy tube to prevent its misplacement after any disconnection.

Abstract: Small tracheostomy appliances for use in treating Sleep Apnea Syndrome. The appliances are inserted in a tracheotomy incision, low on a patient's neck to equalize intra-tracheal pressure with ambient pressure under certain conditions to prevent undesirable increases in blood CO2 that could otherwise cause arousals from sleep.

Abstract: A fluid delivery and airway management device including a tubular member dimensioned for introducing a fluid into a trachea of a mammal, the tubular member having a proximal portion, a distal portion, and a middle portion between the proximal portion and the distal portion. The tubular member is dimensioned for positioning of the proximal portion in an oral cavity of a mammal, the middle portion in an oropharynx of the mammal and the distal portion in an esophagus of the mammal. An inflatable oral cavity balloon is positioned at the proximal portion and dimensioned to occlude the oral cavity. An inflatable esophageal balloon is positioned at the distal portion and dimensioned to occlude the esophagus. Apertures may be formed within the middle portion such that a fluid introduced into the tubular member is output through the apertures to a trachea.

Abstract: The invention relates to a laryngeal mask airway device (1) for insertion into patient to provide an airway passage to the patient's glottic opening, the device (1) including an airway tube (2), a mask (3) attached to the airway tube (2), the mask (3) including a body (4) having a distal end (5) and a proximal end (6), a peripheral inflatable cuff (7), and an outlet (8), the mask (3) being attached to the airway tube (2) for gaseous communication between the tube (2) and the outlet (8), the device (1) further including a structure to prevent occlusion of the outlet (8) by the patient's anatomy, the structure including a support (11), and a conduit (28a) to allow gas to flow out of the outlet (8), past the support.

Abstract: Various embodiments of a tracheal tube having a suction lumen are provided. For example, the suction lumen may be associated with two spaced apart pressure transducers, whereby a pressure drop between the transducers indicates that the suction lumen is free of blockages and a characteristic lack of pressure drop and/or particular pressure curve is indicative of a blockage. In addition, embodiments may include a tracheal tube with sensors configured to sense a buildup of secretions. The sensors may be located proximate to an opening in the suction lumen. In other embodiments, a blockage-clearing system for a suction lumen may be provided that blows air into the suction lumen to clear blockages. In particular, in certain embodiments, the blockage-clearing system may operate to create its own pressurized air source by utilizing the pressure change created in the suction line by a blockage.

Abstract: Under- and overinflation of retention balloons and cuffs for catheters including Foley catheters, and for endotracheal tubes, tracheostomy tubes, laryngeal mask airways and similar devices is correlated with hospital acquired infections and with patient injury. In this patent, a solution that correctly inflates inflatable retention devices is taught, whereby a pressure release means is incorporated into the inflation pathway from the fluid input syringe to the retention means while inflating. This pressure release means can be set to open at or near the optimal fluid pressure so that overinflation can be prevented by releasing any pressure above the optimal pressure and underinflation can be prevented by a user pressurizing the cuff until the valve is noticed to open. As well, observation of fluid leaked through the pressure relief means can indicate misplacement of the retention means, allowing the user to reposition it before patient injury occurs.

Abstract: A laryngeal mask airway device for insertion into a patient to provide an airway passage to the patient's glottic opening. The device includes an airway tube, a mask attached to the airway tube, a peripheral inflatable cuff, and an outlet for gas. The mask is attached to the airway tube for gaseous communication between the tube and an outlet. The device further includes an oesophageal drain that includes a conduit that extends from an inlet at the distal end of the mask to an outlet disposed outside the patient when the device is in place. The conduit includes a mask section and airway tube section, wherein the mask section is formed integrally in the material of the body of the mask.

Abstract: A pilot balloon assembly for a tracheal tube includes a pilot balloon guard for a pilot balloon. The pilot balloon guard includes an enclosure having walls that define an interior volume that is greater than an interior volume of a pilot balloon. The pilot balloon is received by the enclosure and inflates within the enclosure to indicate inflation of a cuff of the tracheal tube. The pilot balloon guard enclosure absorbs externally applied forces to prevent transfer of the externally applied forces to the pilot balloon.

Abstract: An air-operated speech aid that includes a cover cup, a tube, a sound guide tube, a gasket, and an internal tube. The cover cup of the speech aid is provided with a breathing hole, and a side of the breathing hole is clasped into a soft air gate. One end of the sound guide tube is encased in a sleeve or a mask type cover member.

Abstract: A tracheal tube assembly includes a cannula connector that includes a cannula connector cap coupled to a flange assembly. The flange assembly is in turn coupled to a cannula. The flange assembly includes a portion that extends through slots formed at or near a proximal end of the cannula connector cap. The flange assembly may be overmolded.

Abstract: In some embodiments, an airway assembly may be used in a procedure that requires tracheal intubation. The airway assembly may include a first conduit, a sleeve, and a stent. The first conduit and the sleeve may be relatively flexible, facilitating insertion of the airway assembly in a body lumen (e.g., an air passage way). The first conduit may function to deliver gases (e.g., air) to the body lumen and consequently the patient. The first conduit may be positioned in the sleeve during use. The sleeve may be removably coupled to the first conduit. In certain embodiments, a sleeve may function to inhibit a stent from expanding until desired. In some embodiments, an elongated member may be positionable in the first conduit. The elongated member may be configurable to substantially retain a new shape upon deformation. The stent may be coupled towards the distal end of the first conduit. The stent may function to inhibit the body lumen from collapsing.

Abstract: A device and a method for the percutaneous placement of a tracheostomy tube composed of a handle, an inflatable balloon having a reversed truncated cone shape, a tube to inflate the balloon and another to contain a wire guide, a plastic structure in the middle between the balloon and the handle made of laminar elements to strengthen the apparatus movements of the handle transmitted to the tube and the balloon. Following placement of the tracheal tube, the balloon is deflated and the apparatus or device withdrawn.

Abstract: The self-cleaning and sterilizing medical tube may include a combination of an endotracheal tube or a tracheostomy tube and a suction catheter that decreases the tendency of mucus and bacteria to adhere to the inner surfaces of the thereof. The medical tube may have a hydrophobic surface exhibiting the lotus effect, which may be formed either by femtosecond laser etching or by a coating of poly (ethylene oxide). Alternatively, the medical tube may be formed with a photocatalyst incorporated therein or have a lumen coated with a photocatalyst. The medical tube may also have a light source and a fiberoptic bundle mounted thereon, the optical fibers extending into the lumen to illuminate the photocatalyst.

Abstract: An airway management device including a tubular member dimensioned for introducing air into a trachea of a mammal, the tubular member having a proximal portion, a distal portion, and a middle portion between the proximal portion and the distal portion. The tubular member is dimensioned for positioning of the proximal portion in an oral cavity of a mammal, the middle portion in an oropharynx of the mammal and the distal portion in an esophagus of the mammal. An inflatable oral cavity balloon is positioned at the proximal portion and dimensioned to occlude the oral cavity. An inflatable esophageal balloon is positioned at the distal portion and dimensioned to occlude the esophagus. Apertures may be formed within the middle portion such that air introduced into the tubular member is output through the apertures to a trachea.

Abstract: The invention concerns a collar with a tracheotomy cannula or tube, wherein the collar embraces a respiratory tube in sealing relationship. The collar comprises separate inner and outer films, the outer film being elastically stretchable. The collar of the device allows no or only small tight folds formed which do not affect sealing integrity between the collar and the trachea wall even at low pressures. The outer film is expandable to a diameter larger than the diameter of a trachea, and in particular is at least 1.5 times the outside diameter of the tube, and the inner film comprises a material of lower elastic stretching. The inner film is produced oversized and without an external restriction at an internal pressure of at most 20 hPa assumes a diameter which is larger than the diameter of a trachea.

Abstract: A pulmonary secretion clearing airway structure and related airway management system is disclosed that has a double lumen portion which each lumen of the double lumen portion operably secured to an airway management system so that inspiratory fluid (air/oxygen mixtures, with or without added water vapor) is delivered to the distal end of the ventilation catheter through one of the two lumens and expired inspiratory fluid, pulmonary secretions, and pulmonary fluids are removed from the patient through the other lumen. The expiratory fluid pathway preferably includes a secretion collection system for removing the pulmonary secretions and the like from the pathway, thereby improving operation and safety of the system. The airway structure can be a ventilation catheter or a supraglottic airway system such as laryngeal mask and the like.

Abstract: A larynx tube (10) for ventilation has a tube shaft (12), which has a ventilation lumen (18), having an oesophageal cuff (28) which is arranged on the tube shaft (12) for blocking the esophagus (14) and having a drainage channel (46) which has a drainage opening (48?) which is arranged distally in respect of the oesophageal cuff (28). The drainage channel (46) is formed by a drainage pipe (44) which is arranged in a longitudinal groove (42) of the tube shaft (12) which is provided on an outer side (40) of the tube shaft (12). The drainage pipe (44) is adhesively bonded and/or welded to the tube shaft (12). The tube shaft (12) has a proximal and a distal longitudinal shaft portion (56, 58) which are adhesively bonded and/or welded to each other. The distal longitudinal shaft portion (58) is constructed as an injection-molded component.

Abstract: A supraglottic airway of the type used to facilitate lung ventilation and the insertion of endo-tracheal tubes or related medical instruments through a patient's laryngeal opening where the shield is designed to have an internal increase in pressure during assisted inhalation such as positive-pressure ventilation.

Abstract: A flexible expandable inter vivos tube includes at least one arched segmented portion, a corresponding movable element and at least one positioning mechanism. The at least one arched segmented portion and corresponding movable element forming a flexible closed longitudinally expandable tube. The at least one arched segment includes an H-shaped connector having at least one cavity that allows variable slidable movement of a free end portion of the corresponding movable element. To move one or more of the movable elements of the expandable tube, which are within a cavity of the “H”-shaped connector, a fluid or air is introduced into the H-shaped connector running along the longitudinal axis of the flexible expandable inter vivos tube, so that the hydraulic or air pressure within an inner rib of the H-shaped connector expands the movable elements and, thus, the circumference and diameter of the flexible inter vivos tube are increased.

Abstract: A tracheal tube apparatus includes a cannula having first and second ends. An inflatable cuff is formed on the cannula between the first and second ends. A conduit extends from the cuff for introducing an inflating fluid into the cuff when it is desired to inflate the cuff and removing inflating fluid from the cuff when it is desired to deflate the cuff. A gauge for indicating the inflation pressure of the cuff is coupled in the conduit.

Abstract: An inflatable balloon cuff may be adapted to seal a patient's trachea when associated with an endotracheal tube. Configurations of these cuffs that include tapered regions with certain characteristics, such as cuff wall diameter and thickness, may provide improved sealing of the trachea.

Abstract: A flexible expandable inter vivos tube includes at least one arched segmented portion, a corresponding movable element and at least one expansion mechanism. The at least one arched segmented portion and corresponding movable element forming a flexible closed longitudinally expandable tube. The at least one arched segment includes an H-shaped connector forming cavities that allows variable slidable movement of a free end portion of the corresponding movable element. To move one or more of the longitudinal segments of the expandable tube, which are within the cul-de-sac cavities of the H-shaped connector, a sliding mechanism within the H-shaped connector moves from a first position to a second position to cause the expansion mechanism to expand such that the diameter of the flexible inter vivos tube is increased.

Abstract: The present invention relates to an oro-tracheal tube for interventions of tracheotomy that, at least in the distal end (12) has flattened section, more extended along the transverse axis and less extended along the sagittal axis, and that, in the vicinity of the end of said distal portion is provided with asymmetric expandable means, which expand mainly towards the front.