WO2010100592A1

WO2010100592A1 - Pneumatic self retaining surgical retractor system

Info

Publication number: WO2010100592A1
Application number: PCT/IB2010/050866
Authority: WO
Inventors: Shantha Dr. Lenadora
Original assignee: Dr Lenadora Shantha
Priority date: 2009-03-03
Filing date: 2010-03-01
Publication date: 2010-09-10
Also published as: EP2403414A1

Abstract

The present invention relates to a tissue-friendly pneumatic self-retaining surgical retractor system. The retraction action is achieved by the separation of two longitudinal retractor bars, carrying a multiple of retractor blades (27) of variable sizes and shapes, driven by a pair of pneumatic cylinders (3). It also consists of a pair of transverse retractor bars (28) which can be articulated on to the longitudinal retractor bars (11,20) to form a suitable aperture of desired size. The said rectangular retractor bar formation along with retractor blades can be isolated from the activation system to enhance the surgical access.

Description

Description Title of Invention: PNEUMATIC SELF RETAINING SURGICAL

RETRACTOR SYSTEM

[i]

Technical Field

[2] This invention relates to a self retaining surgical retractor system which is driven by pneumatic pressure. Background Art

[3] This invention claims priority over Sri Lankan patent application number LK/

P/l/15308 dated March 3. 2009.

[4] This invention relates to a pneumatically driven self retaining surgical retractor system which can be used for retracting human or animal tissues during surgical procedures. During the course of many surgical procedures anatomical features or tissues surrounding the surgical field are separated and retracted by means of manual retractors which are held by assistants to gain physical and visual access to the surgical site. Alternatively self retaining retractors do not require trained personnel. Most self retaining retractors are rigid and are made to retract the surgical wound in a manner such that manipulations and movements by the surgeons as well as the counter pressure caused by retracted tissues or contracting muscles result in microscopic and macroscopic damage to tissues which adds to the true surgical trauma and is associated with higher incidence of pain, fever, infection and post operative hospital stay. Most self retaining retractors of prior art have a fixed number of retractor blades and a limited range of retraction and have a constant retraction force. There remains a need for a tissue-friendly self retaining retractor system, capable of retracting tissues without causing undue injury to tissues. The present invention refers to a pneumatically operated self retaining retractor system that offers a tissue-friendly cushioning retraction force, because it is driven by two columns of compressed air. Its ability to accommodate multiple numbers of retractor blades of varying shapes and depths is an added advantage. It also provides a rectangular retraction aperture in which the dimensions can be varied in both longitudinal and transverse directions to suit each surgical procedure. Disclosure of Invention Disclosure

[5] A pneumatic self retaining surgical retractor system comprises of a static component with an attached pneumatic driving unit, a telescopic sliding component with retraction holding clamps, a retractor bar component with sliding locks and a set of tissue retractor blades (Figl).

[6] The static component comprises of a rigid tubular base member 1 (Figs. 1, 2 & 3), to which two parallelly placed syringe holders 2, are fixed at its ends. In the present embodiment of the pneumatic self retaining surgical retractor system, two disposable syringes 3, are releasably secured onto the syringe holders 2, by means of two screw locks 4. The nipples 6, of both disposable syringes, are fixed onto nipple sockets 5 (Fig 4 and 11) located on the base member 1, at the base of each syringe holder 2. The nipple sockets are interconnected through the hollow of the base member which acts as a pneumatic pressure transmission tube. An air inlet valve 7, is connected to this pneumatic pressure transmitting tube (base member 1- Figs 3 and 4). When the pneumatic system is activated by a stream of compressed air pushed through the air inlet valve 7, the plungers 8, of both disposable syringes 3, are made to drive back to produce a repulsive force required for the retractive action. There are two parallel static longitudinal retractor bar holders 9 fixed onto either side of the base member 1. At the end of each static longitudinal retractor bar holder 9 there is a slot and screw mechanism 10, to fasten each end of static longitudinal retractor bar 11.

[7] The sliding component comprises two parallelly placed tubular elements fixed close to either end of the base member 1, which acts as the inner (male) member 12, of the telescopic sliding component providing a guide to a pair of outer tubular member (female) 13, which are made to slide in and out over the said inner member (male) 12, completing a telescopic sliding mechanism. The outer (female) members 13 are interconnected by a cross member 14 for proper alignment. At the end of each outer tubular (female) member 13 of telescopic sliding mechanism, there is a push pad 15, which transmits the force generated by the plunger 8 of each disposable syringe 3 to the outer tubular member (female) 13 of the telescopic sliding mechanism (Fig 5).

[8] The sliding component of the pneumatic self retaining retractor system comprises of said two parallelly placed outer tubular (female) members 13 and a pair of mobile longitudinal retractor bar holders 16. Each mobile longitudinal retractor bar holder has a short tubular component 17 which is made to slide over the said outer tubular (female) member 13 of the telescopic sliding mechanism. A mounting screw 18, on each short tubular component 17 enables the fixation of mobile longitudinal retractor bar holder 16, to the underlying outer (female) 13 member of the telescopic sliding mechanism. The respective mounting screws 19 on each mobile longitudinal retractor bar holder 16 enables the fixation of each end of mobile longitudinal retractor bar 20 (Fig 5).

[9] Each retraction holding clamp 21 (Fig 6) of the said retractor system comprises of a larger tubular ring 22 which slides over the syringe holder 2 connected to a smaller tubular ring 23 which slides over the outer tubular (female) member 13. This could be releasably clamped on to the syringe holder 2 by tightening the screw mounted on the larger tubular ring 22. Once the respective screw 24 is tightened, the back movement of the mobile retractor bar holder 16 can be arrested at any position. This feature is employed during the extension procedure.

[10] The tissue retractor bar component of the present invention comprises of a static longitudinal retractor bar 11 and a mobile longitudinal retractor bar 20 which are structurally similar to each other. Each longitudinal retractor bar 11,20 (Fig 7) has threaded holes 25 at both ends to accommodate respective screw 10,19 mounted at each end of static longitudinal retractor bar holder 9 and mobile longitudinal retractor bar holder 16. Each retractor bar has drilled holes 26 along its length at regular intervals to accommodate multiples of retractor blades 27. Once fitted, both static and mobile longitudinal retractor bars are placed parallel to each other (Fig 12).

[11] In the present embodiment two transverse retractor bars 28 which are structurally similar to said mobile 20 and static 11 longitudinal retractor bars are employed to form a slidable rectangular retractor frame. Each transverse retractor bar 28 has two sliding locks 29 which are used to articulate them on to both longitudinal retractor bars to complete the said rectangular retractor frame. At the end of each transverse retractor bar 28, there is a pin 30 to prevent accidental dislodging of sliding locks 29 from the transverse retractor bars. The sliding locks 29 on each transverse retractor bar 28 (Fig 8) comprises of a short rectangular channel 31 which is made to accommodate the transverse retractor bar 28. There is another rectangular channel 32 placed right angled to the said channel with a slot 35 at its base enabling the insertion of corresponding longitudinal retractor bar 11,20 . Each rectangular channel has mounting screws 33,34 to fasten it onto the respective retractor bar. When tightened, each screw will lock the free movement of the respective retractor bar. When all screws of the sliding locks 33,34 are tightened, the retractor bar component comprising of static and mobile longitudinal retractor bars and two transverse retractor bars form a rigid rectangular retractor frame of desired size (Fig 10).

[12] In the present embodiment, retractor blade component of the pneumatic self retaining retractor system comprises of a set of U shaped retractor blades 27 which have slightly out-curved blunt distal ends. Each retractor blade 27 has two insertion pins 36 . They are made to be clipped on to multiple holes 26 provided at regular intervals along the length of all four retractor bars. The spring action of the U shaped retractor blades enable to secure them on to any retractor bar. In addition there is a self- locking mechanism provided in each insertion pin to avoid accidental dislodging of retractor blades whilst in use. This self locking mechanism comprises of a groove on each insertion pin 37 of retractor blade where both edges of the said groove sit on the body of retractor bar especially when the counter pressure created by the tissue load which results in a slight inward tilt of the retractor blade 27 (Fig 9). [13] Retractor blades can be removed from corresponding retractor bars when required, by pressing on the pins to counteract the spring action while pulling it away from the retractor bar. The pneumatic retractor system can be mounted onto the operating table by using the mounting screws 38 provided at both ends of the base member 1.

[14] Application procedure

[15] Following the sterilization of all the components of the present embodiment, two sterile disposable syringes 3 are properly fixed and secured to the syringe holder 2 by tightening the mounting screws 4 located at the syringe holder 2, and a disposable two way tap is connected to air inlet valve 7. Both static and mobile longitudinal retractor bars are fixed to respective bar holders, and a suitable number of retractor blades are clipped on to both static and mobile longitudinal retractor bars (Fig 1 and 12).

[16] Once the surgical incision is made, the retractor bar component with attached retractor blades of the system can be inserted into the surgical wound. The pneumatic pressure can be applied through the air inlet valve 7. As the air pressure increases in the system, the disposable syringes 3 are retrogradely inflated. Thus the plungers are pushed away and the telescopic sliding mechanism moves the mobile longitudinal retractor bar holders 16 along with the attached mobile longitudinal retractor bar 20 away from static longitudinal retractor bar 11. The retraction force thus created is transmitted to tissues of the surgical incision via the attached retractor blades 27. The retraction can be advanced by continuous air pressure until desired retraction is achieved at the surgical incision (Figs 1 and 12).

[17] The pneumatic driving system provides a tissue-friendly soft cushioning action as it enables the muscles to negotiate and attain an equilibrium during the retraction process. As the muscle relaxation which is achieved by anesthetic drugs fades off, retracted muscles start exerting more force on the retractor blades. Since the retractor is driven by a column of compressed air, the increase in force exerted by the tissues press on the column of air trapped in each syringe resulting in a slight backward movement of the pistons of both syringes from the achieved position. This will be readily reflected on the calibration marks of both syringes. This movement is a valuable indicator to the surgical team and the anesthetist could top up the anesthetic relaxation of the patient, thereby minimizing any tissue damage, which would otherwise result in anoxic and physical damage to retracted tissues. Thus the present self-retaining surgical retractor system incorporates a useful indicator of the extent of muscle relaxation.

[18] In the present embodiment, retraction with both longitudinal retractor bars result in retraction of tissues and muscles in the transverse direction (of the human body). Retraction in longitudinal direction of the human body can be achieved by using a pair of transverse retractor bars 28. Once the transverse retractor bars 28 are suitably ar- ticulated to the longitudinal retractor bars 11 and 20 by employing the sliding locks 29 as mentioned above, the system provides adequate surgical exposure in both longitudinal and transverse directions. The presence of transverse retractor bars 28 once articulated properly to both longitudinal retractor bars 11, 20 via the sliding locks 29, will not restrict free movement of mobile longitudinal retractor bar 20. In case of further expansion of surgical aperture, sliding locks 29 will facilitate free sliding of transverse retractor bars 28 on the longitudinal retractor bars 11 and 20 while retaining the rectangular shape of the retraction frame (Fig 1).

[19] The number of retractor blades required on retractor bars depends on the width and length of the surgical incision required. Desired extent of retraction can be obtained by changing the length of retractor blades and the number of retractor blades which are fitted to respective retractor bars. The said self locking mechanism prevents the accidental dislodging of retractor blades especially when there is a tissue load exerted on retractor blades.

[20] The maximum retraction achieved by the pneumatic self-retaining surgical retractor system is determined by the working length of the disposable syringes 3 used. In the present embodiment, the total retraction offered by using common 50cc disposable syringes amounts to approximately 90mm of retraction. In some instances the length of retraction and hence the surgical aperture achieved by the use of these syringes may not be sufficient for a particular surgical procedure. In such situation, the range of retraction can be extended without changing over to much longer syringes by a built-in extension mechanism. Once the maximum retraction is achieved by initial inflation of the syringes the extension procedure can be initiated by sliding the retraction holding clamp 21 along the outer tubular member (female) 13 . The retraction holding clamp 21 is moved until it touches the short tubular component 17 of mobile longitudinal retractor bar holder 16 . At this position, the retraction holding clamp 21 can be secured onto the syringe holder 2 by tightening the respective screws 24. Then the respective screw 18 of the mobile retractor bar holder 16 over the outer tubular member (female) 13 can be loosened to make it independent from the telescopic sliding mechanism. At this stage the tissue load offered onto the mobile retractor bar holders 16 will be automatically transferred to the syringe holder 2 via the secured retraction holding clamp 21. The pneumatic system can now be deflated safely while maintaining already achieved retraction by releasing the air through the air inlet valve 7. At this point the pneumatic driving system with said telescopic system is free to be pushed back to its initial position without affecting already achieved tissue retraction. The pneumatic driving system along with attached syringes are now ready to be inflated again to extend the retraction up to another full span which amounts to extra 90mm. The respective screws on mobile longitudinal retractor bar holder 18 over the outer tubular member (female) 13 of the telescopic sliding component can be tightened and the system can be re-inflated by compressed air similar to the first step. This user- friendly extension mechanism permits usage of even smaller syringes with smaller span so that the driving system can even be made smaller than the present embodiment.

[21] The retractor system can be safely deflated and removed from the patient by releasing the compressed air through the air inlet valve 7.

[22] During the surgical procedures of prolonged duration the surgeon might prefer to relax the retractor periodically in spite of tissue-friendly retraction provided by this self-retaining retractor to ensure tissue perfusion. In the event of such requirement, the retraction holding clamps 21 can be tightened to respective syringe holders 2 at a desired point in a manner similar to the above, and the system can be deflated without allowing a complete collapse of the retractor. The system can be re-inflated when needed to achieve previous retraction after a suitable time interval. This procedure can be practiced even during the extension procedure.

[23] In some instances it may be beneficial for surgical procedures to be performed with a rigid retractor frame aperture as compared to variable rectangular surgical aperture as achieved by present invention. In case of this requirement, the retractor frame which consists of longitudinal and transverse retractor bars can be locked on each other at any suitable position by tightening the respective screws 33,34 on the sliding locks so the slidable rectangular frame can be converted to self-supporting rigid rectangular frame structure. Once this is done, the pneumatic driving system, the sliding component, and all the retractor holders can be detached and removed from the rigid rectangular frame by releasing all respective mounting screws 10,19 on the retractor holders 9,16 (Fig 10). This isolates the rectangular retractor frame of desired size along with attached retractor blades. This embodiment can provide extra space for the surgical procedure.

[24] Thus the present disclosure provides a surgeon-friendly and a tissue-friendly self- retaining retractor system. Variable retraction aperture, ability to hold multiple numbers of retractor blades of various depths, in-built extension mechanism, the ability to convert into a rigid rectangular retraction frame of desired size and its ability to maintain the retraction as an isolated retractor frame are added advantages. Description Of Drawings

[25] Fig 1 The complete assembly of the Pneumatic self retaining surgical retractor system

[26] Fig 2 Static component of the retractor system

[27] Fig 3 Elevation of static component

[28] Fig 4 Details of nipple socket

[29] Fig 5 Sliding component with mobile retractor bar holder [30] Fig 6 Retraction holding clamp

[31] Fig 7 Longitudinal retractor bar with two retractor blades

[32] Fig 8 Transverse retractor bar with a retractor blade and a sliding lock

[33] Fig 9 Details of insertion pin of retractor blade

[34] Fig 10 Retraction frame isolated from the activation system

[35] Figl 1 Cross section of the syringe and its assembly

[36] Figl2 Retractor system with longitudinal retractor bars and blades

Claims

[Claim 1] A Pneumatic Self-Retaining Surgical Retractor System, for use in retracting tissue of a patient, during a medical procedure comprising: a compressible retracting system having a flexibility function a pneumatic driving component a telescopic sliding component a combination of static and mobile longitudinal retractor bar system a slidable transverse retractor bar system a sliding lock for the retraction bar components a retraction holding clamp and extension facility a detachable retractor frame of variable aperture a self- locking retractor blade system.

[Claim 2] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein the retraction force is applied by a pneumatic cylinder system

[Claim 3] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein the retraction system incorporates a flexibility provided by either an air column or any other compressible media

[Claim 4] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein the retraction force will be in equilibrium with the resistance offered by the retracted tissues.

[Claim 5] The Pneumatic Self- Retaining Surgical Retractor System in claim 1 comprising a feedback signal through a calibrated indicator.

[Claim 6] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein the movement is guided by a telescopic guide

[Claim 7] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein one longitudinal retractor bar is forced to move relative to another longitudinal retractor bar using a pneumatic force

[Claim 8] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein a combination of retractor bars is used to form an aperture of any rectangular shape or size

[Claim 9] A method of self-locking of retractor blades comprising a depression in the insertion pin

[Claim 10] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein self-locking retractor blades can be fixed on to the retractor bars.

[Claim 11] The Pneumatic Self-Retaining Surgical Retractor System in claim 1 wherein the retraction could be held rigidly using a retraction holding clamp mounted on the main frame. [Claim 12] The Pneumatic Self- Retaining Surgical Retractor System in claim 1 wherein the aperture can be held rigid at any required position. [Claim 13] The Pneumatic Self- Retaining Surgical Retractor System in claim 1 wherein the retraction can be relieved temporarily. [Claim 14] The Pneumatic Self- Retaining Surgical Retractor System in claim 1 wherein the retractor bar system could be isolated from the driving system.