Abstract:
The present invention is directed towards surgical devices and a method used in minimally invasive surgery whereby a device is incorporated into or onto an instrument to strengthen its shaft and improve its functionality in minimally invasive surgery. The primary goal of the invention is to increase the strength and rigidity of an instrument by using a specially designed sleeve that strengthens the instrument, thereby reducing its ability to bend and increasing its load carrying capacity. The invention will provide a system that gives extra strength and rigidity to small instrument shafts, so that surgeons can still safely and reliably perform their procedures, but can also use incisions that are as small as possible.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 62/129,743, filed on Mar. 6, 2015, which is herein incorporated by reference in its entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The present application is directed toward medical instruments and, more particularly, to a specialized medical strengthening sleeve used in minimally invasive surgery. 
       BACKGROUND OF INVENTION 
       [0003]    Laparoscopy is a surgical procedure performed through small incisions in the abdomen whereby a trocar device is inserted to provide a means for passage of medical instruments. A thin cylindrical instrument called a laparoscope, connected to a camera, is then used to provide a clear picture of the abdominal cavity to the surgeon. 
         [0004]    In particular, prior to starting a surgical procedure a small incision is made in the abdominal wall of the patient whereby a trocar/cannula device is inserted. Trocar device diameters range in size from 5 to 12 mm and provide a clear passage for the introduction of medical devices into the abdomen. Once the abdominal opening is secured, a laparoscope is inserted thru the trocar opening permitting the surgeon to view the abdominal cavity space. Typically, several additional incisions are made ranging in size from 5-12 mm for the introduction of other medical devices. A device called an insufflator is also used; its purpose is to inflate the abdominal cavity area with carbon dioxide and create space. The space created provides a greater working and viewing area for the surgeon. 
         [0005]    Minimally invasive surgeries such as laparoscopies may provide a host of benefits as compared to traditional surgeries using large incisions, including lower operating cost, less patient trauma, less scarring, less pain, lower surgical complications, quicker recovery times, shortened hospital stays, and less chance of infection. 
         [0006]    As the field of minimally invasive surgery continues evolving, less invasive techniques are desired. The need for smaller laparoscopic tools has also arisen. In recent years, a newer version of laparoscopy has evolved called needlescopic surgery. Needlescopic surgery is a progression of laparoscopic surgery whereby incisions smaller than 3 millimeters are made. Virtually no scarring occurs, pain is reduced, and recovery times are faster. However the problem associated with this new type of procedure is the limited functionality of the insertion instrument. As the instruments became thinner, the heads of the instruments became smaller and less effective to manipulate tissues and organs. For this reason among others, needlescopic surgery has not been widely adopted by the surgical community. 
         [0007]    Another new type of surgery called Single Incision Laparoscopic Surgery (SILS) has also been tried to reduce the number of incisions related to surgery. The concept is that a single incision is made at the umbilicus allowing a specialized tool to be placed at the opening. The opening allows the insertion of several very small instrument tools into the abdomen. The problems associated with this procedure are first in the level of complexity for each procedure versus the traditional laparoscopic procedure, the lack of functionality of the smaller tools, and the very tight working area. It is usually limited to only 3 very small instrument devices which often lack the full functionality required by traditional surgeons. 
         [0008]    Another new type of surgery used today is called Natural Orifice Translumenal Endoscopic Surgery (NOTES). It basically involves placing a flexible endoscope through one of the body&#39;s natural orifices, like the mouth, anus, vagina, or urethra. Its purpose is to achieve access to a space near the affected area. Some of the problems associated with this type of surgery are that the number of instrument heads used is usually limited to only one, not all areas of the body are accessible, and since most views are two dimensional there are special orientation problems. 
         [0009]    An additional problem associated with both Single Incision Laparoscopic Surgery (SILS) and Natural Orifice Translumenal Endoscopic Surgery (NOTES) is the inability to achieve triangulation. Triangulation in this instance can be defined as the ability to come at a target from different directions or angles. Triangulation provides significant benefits to the surgeon, among them are: effective control of the surgical procedure and the ability to better manipulate internal body parts. When this ability is lost it is difficult to effectively perform these types of surgeries. This is one of the reasons that have prevented SILS and NOTES from being widely adopted. 
         [0010]    People have experimented with the concept of attaching larger instrument heads to thin shafts inside the body, but no effective method has been developed or invented to facilitate the insertion and attachment of such instrument heads within the body, especially under direct visualization. 
         [0011]    It has been a long term goal of minimally invasive surgeons to perform surgery with the absolute smallest incisions while providing the means of visualization of the intended area. Therefore there is a need in the field for a means of effectively attaching and securing full-sized laparoscopic instrument heads to small diameter instrument shafts within the body while under direct visualization. This need would minimize the number and size of incisions performed for each procedure. The challenge with this approach is that the current methods used require additional trocar/cannula openings. 
         [0012]    In laparoscopic surgery, incisions are made ranging from 5-12 mm and usually require up to 4 separate incisions. In the specialized field of needlescopic surgery the instrument heads are often too small and lack functionality. Visualization of the attachment process is also a problem that has limited the internal attachment process to an external one. The challenge has been in finding a means of inserting, removing and remotely attaching a normal sized medical instrument head inside the abdomen of a patient. The benefits are numerous to the patient including; reduced scarring, quicker recovery times, less chance of infections, and lower morbidity risks associated with infections. The advantages to the surgeon are better handling, and better functionality of the instrument heads, often a trade off that is associated with smaller instrument heads. 
         [0013]    As newer technologies continue to evolve, there is a need in the field for smaller tools having better rigidity and strength characteristics. In U.S. Provisional Application Ser. No. 62/093,789, filed on Dec. 18, 2014, entitled “Method and Apparatus for Securing Laparoscopic Instrument Heads in the Abdomen Under Direct Visualization”, which is hereby incorporated by reference herein in its entirety, a new technology was disclosed whereby thin shafts having diameters measuring between 1-4 mm are introduced into a patient&#39;s body. As elongated instruments continue to reduce in diameter, however, rigidity of such instruments can become problematic. In particular, the further such instruments are extended the weaker they become. Therefore it is the goal of this invention to provide a means of providing rigidity and enhanced strength to elongated medical instruments by the introduction of a strengthening sleeve device. 
         [0014]    These and other aspects, features and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments which follow. 
       SUMMARY OF INVENTION 
       [0015]    The present invention is directed towards surgical devices and a method used in minimally invasive surgery whereby a device is incorporated into or onto an instrument to strengthen its shaft and improve its functionality in minimally invasive surgery. The primary goal of the invention is to increase the strength and rigidity of an instrument by using a specially designed sleeve that strengthens the instrument, thereby reducing its ability to bend and increasing its load carrying capacity. 
         [0016]    Medical device manufacturers aim to reduce medical instrument shaft diameters so that they can reduce the size of the skin incisions, but this has resulted in small diameter instrument shafts that can bend or break easily. The goal of this invention is to provide a system that gives extra strength and rigidity to those small instrument shafts, so that surgeons can still safely and reliably perform their procedures, but can also use incisions that are as small as possible. 
         [0017]    The strengthening sleeve device is an assembly that can be attached onto an instrument, or be incorporated into one. It incorporates a collapsible tube assembly, which surrounds the smaller diameter instrument shaft and imparts extra strength to resist bending. The strengthening sleeve covers the part of the instrument shaft that is outside of the body during laparoscopic procedures. As the instrument is pushed into the body and pulled out of the body during minimally invasive surgical procedures, the strengthening sleeve will collapse or expand as the instrument moves, such that it covers the entire part of the instrument shaft that is outside the body at any given time. Since the larger diameter strengthening sleeve always remains over the part of the instrument that is outside the body, and does not enter or interfere with the skin incision, the incisions can remain as small as possible. The assembly may also include a manually adjustable locking knob, a proximal end spring retainer, an elongated spring, a collapsible tube assembly, a distal end spring retainer, a swivel ball joint assembly, a foot device, an adhesive pad, and suture holes. 
         [0018]    The sleeve device is attached to the outer shaft of a medical instrument so that as the instrument is moved in or out, the sleeve device also collapses or extends. This collapse and extension of the strengthening sleeve can be achieved manually or in an automatic fashion, relying on springs, weights, an anchored base, or any other method that would allow the strengthening sleeve to adjust its length along with the instrument&#39;s movement. In one embodiment, springs are used to maintain full coverage of the strengthening sleeve over the part of the shaft outside the body. For example, as pressure is applied forward on an instrument handle the strengthening sleeve compresses itself resulting in the shortening of the strengthening sleeve and the physical movement of the shaft further into the body. 
         [0019]    The instrument strengthening sleeve device covers the instrument from the proximal part of the shaft, near the handle, down to the foot device at the distal end of the strengthening sleeve. The foot device remains in contact with the skin at all times, and can be slid there manually or held there with the assistance of an adhesive pad, sutures through holes in the foot device, springs which apply a force against the foot device, weights, or any other mechanism that would keep the foot device in contact with the skin, thereby making sure that the strengthening sleeve covers all of the instrument shaft that is outside the body, right down to the skin. There is no specific foot size required with the exception that it must prevent the sleeve from passing through the incision into the abdomen. 
         [0020]    The strengthening sleeve locking knob can be used to lock the strengthening sleeve into a specific length. This can be used to hold an instrument in place or to limit the distance that the instrument can be inserted into the body, which can provide extra safety when initially inserting instruments into the body or when executing careful actions within the body, such as mating instrument heads to instrument shafts. 
         [0021]    The telescoping collapsible tubes that make up the strengthening sleeve can be configured of two or more parts. Its construction can be of titanium, metal alloys, plastics, stainless steel, or not limited to but including any other industry standard materials. 
         [0022]    It should be noted that in similar embodiments the compression of the elongated spring provides additional rigidity and strength to the instrument shaft. This is accomplished by the compression action of the spring(s), forming a wall, further limiting the movement of the shaft that is outside the patient but inside the tube assembly. 
         [0023]    According to an aspect of the invention, the instrument sleeve strengthening device is adapted to strengthen the shaft of an instrument extending sleeve by applying a biasing force to the shaft of the instrument. The instrument sleeve strengthening device may be directly coupled to a proximal part of the instrument, to a port, or may be coupled directly to a patient, and may be permanently coupled to the instrument or manually coupled to the instrument as needed. The instrument sleeve strengthening device also includes a mechanism which applies an equalizing force to the tubular member and is adjustable. As the surgical instrument is extended through the opening the medical instrument is further stabilized by the axial force applied by a ballast spring or other feature. 
         [0024]    These and other aspects of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments which follow. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0025]    The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below: 
           [0026]      FIG. 1  is a perspective view of a strengthening device for a medical instrument, according to an embodiment of the present invention. 
           [0027]      FIG. 2  is a perspective view of the strengthening device of  FIG. 1 , shown fully attached to a medical instrument. 
           [0028]      FIG. 3  is an elevational view of the strengthening device and medical instrument of  FIG. 2 . 
           [0029]      FIG. 4  is a perspective, partial cross-sectional view of the strengthening device. 
           [0030]      FIG. 5  is a cross-sectional view of the strengthening device, taken along line A-A of  FIG. 4 . 
           [0031]      FIG. 6  is a perspective view of the strengthening device in  FIG. 1 , shown in an uncompressed position. 
           [0032]      FIG. 7  is a perspective view of the strengthening device of  FIG. 1 , shown in a compressed position, providing rigidity to an instrument shaft. 
           [0033]      FIG. 8  is a perspective view of a strengthening device according to another embodiment of the present invention, shown in a compressed position, providing rigidity to an instrument shaft. 
           [0034]      FIG. 9  is a perspective view of a strengthening device according to another embodiment of the present invention. 
           [0035]      FIG. 10  is a perspective view of the strengthening device of  FIG. 9 , shown in a compressed position, providing rigidity to an instrument shaft. 
           [0036]      FIG. 11  is a perspective view of a strengthening device according to yet another embodiment of the present invention. 
           [0037]      FIG. 12  is a perspective view of the strengthening device of  FIG. 11 , shown in a compressed position, providing rigidity to an instrument shaft. 
       
    
    
       [0038]    Like reference numerals refer to like parts throughout the several views of the drawings. While the various features of this invention are hereinafter described and illustrated as being particularly adapted for providing rigidity to medical instrument devices the invention is not limited to the embodiments illustrated in the drawings but are merely used to illustrate the wide variety of uses of this invention. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Since numerous modification and changes will readily occur by those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. 
       DETAILED DESCRIPTION 
       [0039]    The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
         [0040]    With respect to  FIG. 1  an isometric view of an exemplary strengthening device or sleeve  100  for an instrument shaft is illustrated. The strengthening device  100  generally includes an attachment mechanism  105  used to attach the device to a medical instrument or device (not shown). As will be described in greater detail hereinafter, the strengthening device  100  includes an upper tube  110  and a lower tube  115  which may enclose one or two elongated spring  130 , depending on the desired usage. In the embodiment illustrated in  FIG. 1 , only the lower tube  115  is illustrated as containing an elongated spring  130 . The upper and lower tubes  110 ,  115  are collapsible tubes or conduits which permit their shortening in total length when compressed. In an embodiment, the tubes  110 ,  115  are telescoping in nature. They may also be composed of more than two tubes, permitting considerable shortening in length. 
         [0041]    As further illustrated in  FIG. 1 , the device  100  also includes a locking assembly  120  that connects the upper and lower tubes  110 ,  115  to one another, and which permits adjusting of the length of elongated spring(s) within the tubes, respectively. A swivel ball joint assembly  145  located at the distal end of the lower tube  115  permits pivoting and provides a flexible means of obtaining a desirable entry angle to the surgeon. Attached to the swivel ball joint assembly  145  is a foot  135  which, during use, is placed on the patient near the percutaneous area to restrain the device  100  from sliding inside the patient, as discussed in detail hereinafter. As will be readily appreciated, therefore, the ball joint  145  permits pivoting movement of the foot  135  relative to the lower tube  115  so that device  100  may be stabilized in any orientation. Adjacent to the periphery of the foot  135  are generally equally spaced suture holes  140  are that may be used to physically attach the foot  135  to the patient. In an embodiment, the foot  135  may also, or alternatively, be provided with an adhesive material on its bottom side, allowing the foot  135  to be adhered to a patient&#39;s skin. 
         [0042]    Turning now to  FIGS. 2-5 , the strengthening device  100  is shown fully attached to a medical instrument (e.g., a laparoscopic tool) having a handle assembly  220  attached to an elongate shaft  205 . In particular, as shown therein, attachment mechanism  105  of the device  100  is used to attach the instrument handle assembly  220  to the strengthening device  100 . Pivot point  210  of the handle assembly is used to move a proximal end of the instrument shaft  205 . Two instrument handle finger inserts  216  are used to manually control the movement of handle assembly  220 . An instrument shaft locking knob  215  permits the instrument shaft  205  to be securely held. The upper tube  110  and lower tube are attached and held in place by the locking assembly  120 . By adjusting the locking knob  215  compression on the tube assembly is adjusted. As shown therein, when attached the strengthening device  100 , the instrument shaft  205  extends through the upper and lower tubes  110 ,  115  of the device  100 . A distal end  225  of the shaft  205  protrudes from the lower tube  115  and terminates in an instrument tip  230 . The instrument tip is used to perforate the skin and provide a means for the distal end  225  of the shaft  205  to enter the abdomen of the patient. 
         [0043]    Turning now to  FIGS. 6 and 7 , operation of the strengthening device is illustrated, with  FIG. 5  depicting the strengthening device  100  in its uncompressed position. As shown therein, once the medical device (e.g., a laparoscopic tool) is attached to the device  100 , the instrument tip  230  on the distal end  225  of instrument shaft  205  is utilized to perforate the skin  505  of a patient. Typically the device  100  is initially held with two hands as it is positioned on the patient. The instrument tip  230  is percutaneously passed through a patient&#39;s abdomen and stops when the foot  135  presses against the skin or trocar. As discussed above, foot  135  prevents the device  100  from entering the percutaneous area  505 . The foot  135  may be secured to the patient to prevent movement of the device  100  utilizing an adhesive pad or through the use of sutures provided through apertures  140 . In particular, at his point the surgeon has the option of attaching sutures to the foot  135  through openings  140  to secure the device to the patient, or can expose an adhesive surface on the underside of the foot  135 . The foot  135  also pushes back on the lower tube  115 , thus providing a compression force to the elongated spring housed within the lower tube  115 . The exposed distal shaft  605  is in its normal position in  FIG. 6 . The extent to which the tip  230  of the shaft  205  initially protrudes into the body of the patient (in the uncompressed position) may be adjusted by moving the locking assembly  120  upward or downward (e.g., by rotating). In connection with this, the locking assembly  120  permits the upper tube assembly  110  and lower tube assembly  115  to be held in place at desired lengths through a tightening means. In an embodiment, the tightening means may consist of rotating fixed attachment that can be adjusted by the operator. 
         [0044]    With reference to  FIG. 7 , when it is desired to insert the instrument tip  230  further into the patient, pressure is applied at the instrument handle assembly  220 . In particular, when further reach is required by the surgeon, pressure is applied to the handle assembly  220  and distal portion  225  of the shaft  205  is extended further out. The compression of the elongated spring  130  inside the tube  115  can provide extra support to the shaft, further increasing its strength and rigidity. Indeed, the pressure applied is transferred to both the upper and lower tubes  110 ,  115 . Since the elongated spring is housed within the lower tube  115 , the lower elongated spring  130  compresses, permitting the distal end  225  of the shaft  205  to extend outwards and into the patient. As the lower tube  115  compresses in size, the exposed distal shaft  605  expands directly proportional to the distance moved by the compression of the lower tube  115 . Importantly, the large diameter sleeve (i.e., tubes  110 ,  115  and elongated spring  130 ) surrounds the small diameter instrument shaft  205 , thereby increasing its strength, rigidity and load carrying capacity by adding support and reducing the instrument&#39;s ability to bend. 
         [0045]    Referring now to  FIG. 8 , a strengthening device  400  having an elongated spring within the upper tube  110  is illustrated in use. The instrument tip  230  may be inserted into a patient and the device  400  secured to the body of a patient in the manner described above. When it is desired to insert the instrument tip  230  further into the patient, pressure is applied at the instrument handle assembly  220 , thus compressing the elongated spring and collapsing the upper tube  110 . As the upper tube  110  compresses in size, the exposed distal shaft  605  expands directly proportional to the distance moved. As indicated, the tubes  110 ,  115  and elongated spring within the upper tube  110 ) surrounds the small diameter instrument shaft  205 , thereby increasing its strength, rigidity and load carrying capacity by adding support and reducing the instrument&#39;s ability to bend. 
         [0046]    With respect to  FIG. 9  an isometric view of a strengthening device  300  for an instrument shaft according to another embodiment of the invention is illustrated. Strengthening device  300  is substantially similar to strengthening device  100 , where like reference numerals designate like parts. As shown therein, both the upper tube  110  and lower tube  115  house elongated springs  305 ,  310 , respectively, therein. The use of two elongated springs  305 ,  310  in the upper and lower tubes  110 ,  115  provide a greater degree of rigidity and strength to the medical device and, more particularly, to the shaft  205  of the medical device, as discussed in detail below. As illustrated in  FIG. 6 , the elongated springs  305 ,  310  are preferably fully contained within the upper and lower tubes  110 ,  115 . The tubes  110 ,  115  are collapsible and/or compressible to conform to the elongated springs  305 ,  310 . The telescoping tubes are also collapsible. Typically the upper spring  305  slides into the upper tube  110  and is retrained between the locking assembly  120  and the attachment mechanism  105 . Lower spring  310  slides into the lower tube  115  and is retained between the locking assembly  120  and the swivel ball joint assembly  145 . In particular, the elongated springs  305 ,  310  are held in place by the force they apply at their respective ends. 
         [0047]    Referring now to  FIG. 10 , in operation, as both collapsible tubes  110 ,  115  are compressed by the force exerted on them by the instrument handle assembly  220 , they begin to compress to a smaller length. In particular, as the upper and lower tubes  110 ,  115  compresses in size, their combined compression distance (i.e., shortening) corresponds with the extra distance the exposed distal shaft  605  travels into the patient. Importantly, during this compression, the tubes  110 ,  115  and elongated springs  305 ,  310  surround the small diameter instrument shaft  205 , thereby increasing its strength, rigidity and load carrying capacity by adding support and reducing the instrument&#39;s ability to bend. 
         [0048]    With respect to  FIG. 11  an isometric view of a strengthening device  500  for an instrument shaft according to yet another embodiment of the present invention is illustrated. The strengthening device  500  is generally similar to the device  100  described above, where like reference numerals designate like parts. However, as shown therein, the device  500  includes a single collapsible tube  150  that extends from the foot  135  to the attachment mechanism  105  (rather than upper and lower tubes). In this embodiment, a single elongated spring  405  is housed within the tube  150 . 
         [0049]    As illustrated in  FIG. 12 , in use, after the percutaneous skin is penetrated by the instrument tip  230 , the foot  135  protects the strengthening device  500  from sliding into the patient and also provides a resistance pressure that is used to help compress the elongated spring  405  and collapsible tube  150 . As discussed above, this allows the exposed distal shaft  605  to penetrate further into the patient, while providing support to the portion of the shaft  205  outside of the patient&#39;s body. 
         [0050]    The foot  135  pushes back minimally against the surface of the patient&#39;s skin, thereby not interfering with the normal inward and outward motion of the instrument during the procedure. This force can be adjusted to balance the device against the forces or friction and gravity, or can be reduced or increased to provide a counter force that helps control the instrument&#39;s position. The foot  135  may be fabricated of but not limited to plastics, or metal alloys. It may be secured through suture holes  140  located along the circumference. The foot  135  may be held against the skin with a force from the sleeve, or may be physically attached to the patient via sutures or adhesive materials. In the case that trocars are being used with the instrument, the foot  135  would be pressed against the trocar rather than the skin, but would be held there by the same forces and mechanisms. 
         [0051]    Notably, the device  500  of  FIGS. 11 and 12  provides a great amount of collapsibility and strengthening to an instrument used therewith. As pressure is exerted downwards on the tube  150  and spring  405 , the spring  405  compresses and becomes more rigid, thereby transferring that rigidity to the shaft or medical device. 
         [0052]    In an embodiment, the upper and lower tubes  110 ,  115  of the devices according to the various embodiments described above are made out of plastics, aluminum or metal alloys, although other materials may also be utilized without departing from the broader aspects of the present invention. The upper and lower tubes  110 ,  115  are collapsible, thus decreasing in length as greater pressure is applied permitting the elongated springs therewithin to compress and provide rigidity to the shaft or medical instrument. In an embodiment, the tubes  110 ,  115  may have crimped or ridged edges along their circumference that permit their lengths to collapse and conform to shorter spring length during use, as discussed above. It should be noted that the strengthening devices disclosed herein are not limited to providing rigidity and strength to just a laparoscopic instrument shaft but also other elongated instruments or devices that would benefit from increased load carrying capacity or increased rigidity. 
         [0053]    In any of the various embodiments described above, the compression of the elongated spring provides rigidity and strength to the instrument shaft received therethrough. This is accomplished by the compression action of the spring(s), forming a wall, further limiting the movement of the shaft that is outside the patient but inside the sleeve/spring. 
         [0054]    Importantly, the strengthening device is adapted to strengthen the shaft of an instrument extending sleeve by applying a biasing force to the shaft of the instrument. The device may be directly coupled to a proximal part of the instrument, to a port, or may be coupled directly to a patient, and may be permanently coupled to the instrument or manually coupled to the instrument as needed. The strengthening device also includes a mechanism which applies an equalizing force to the tubular member and is adjustable. As the surgical instrument is extended through the opening the medical instrument is further stabilized by the axial force applied by a ballast spring or other feature. 
         [0055]    Moreover, as discussed hereinbefore, the swivel ball joint assembly  145  allows movement of the strengthening device  100  and shafts supported by the device  100  to pivot at different angles, permitting the distal end of the strengthening device  100  (attached to an instrument head, not shown) to reach areas inside the patient that wouldn&#39;t normally not be accessible while being supported by the foot  135 . 
         [0056]    Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of this disclosure.