fig1 a is a view of the end of the handle of a surgical instrument according to the invention incorporating a bubble level . the dotted circle 102 in the center of the drawing represents a gas bubble . the dark ring 104 outside the bubble represents the target for the bubble . the level helps the surgeon align his instrument . fig1 b is a view of the end of the handle of a surgical instrument with an alternative embodiment of the level . fig1 c is an oblique view of a surgical instrument 108 and the embodiment of the level drawn in fig1 a . fig1 d is an axial cross section of the body , a disc 110 , an adr 112 , an operating room ( or ) table 114 , and the instrument 108 drawn in fig1 c . using the level , the surgeon can assure his instrument , and the attached adr , are perpendicular to the or table . thus , as long as the patient is lying properly on the or table , and the patient does not have a rotational abnormality of the spine , the novel instrument assures the adr is placed with the proper rotational alignment . fig2 is a posterior view of the pelvis 202 , the left lower extremity 204 , and an oblique view of an alternative embodiment of a device 210 used to properly align the cup of a total hip replacement ( thr ). three legs 212 , 214 , 216 from the device are placed around the patient &# 39 ; s acetabulum . the handle 220 of the instrument incorporates the level drawn in fig1 a . the surgeon tightens the connector between the shaft of the instrument and the portion of the instrument that holds the three legs of the device , after the bubble level is centered . the surgeon also records a reading from a circular guide 230 on the instrument . the reading is obtained by recording where a laser light 232 is pointing on the dial . the laser light is attached to a holding device 234 that is attached to the or table 236 . the novel invention records the alignment of a patient &# 39 ; s acetabulum . the surgeon may use the device and the readings recorded from the device to properly align a prosthetic cup of a thr . the prosthetic cup is aligned properly when the legs of the device contact the cup , the handle is level , and the light shines on the proper number on the guide . novel levels can be used on other surgical instruments . fig3 a is a partial sagittal cross section of the spine 320 , two scopes 322 , 324 , a retraction device 326 , and two monitors 330 , 332 . the retraction device 326 is impacted into the disc , and the scopes are held in openings in the retractor . the scopes may be placed through small , separate , incisions . cameras transmit data from the scopes to the monitors . the scopes also transmit light into the retractor . the invention improves upon the use of surgical loupes and the operating microscope . a surgeon &# 39 ; s hands , the handles of the instruments , the shafts of the instruments , and power tools attached to the instrument may obstruct the view provided by surgical loupes and surgical microscopes . this aspect of the invention places the tip of the scopes distal to the object that obstructs the view . use of two or more scopes permits surgeons to see on more than one side of the instrument simultaneously . the improved visualization provide by multiple scopes decrease the risk of injuring structures on the “ blind side ” of a instrument that obstructs the view provided by a single scope . surgeons may observe more than one monitor . alternatively , the data to a single monitor could be changed . voice activated controls could be used to have the view provided by the monitors switch from the “ left ” scope to the “ right ” scope by saying “ right ”. if more than two scopes are used the surgeon could say “ one ” to refer to the scope at the one o &# 39 ; clock position , “ four ” for the scope at the four o &# 39 ; clock position etc . multiple scopes may be placed into other holding devices for other types of surgery . for example , multiple scopes could be placed into a c - shaped ring like device for general surgical procedures , cardiac procedures , and other types of surgical procedures . fig3 b is an axial cross section of an alternative embodiment of the device drawn in fig3 a and a disc . the scopes extend through the left and right sides of the retractor . fig3 c is a lateral view of the retractor drawn in fig3 a . the retractor is drawn in its collapsed shape . the collapsed shape facilitates insertion of the retractor through small incisions . fig3 d is a lateral view of the retractor drawn in fig3 c and two scopes . the retractor is drawn in its open position . fig4 a is lateral view of a power tool 402 , a reamer bit 404 , and a holding instrument 406 according to the invention . prior art instruments are difficult to control . the instruments have long shafts to extend from a patient &# 39 ; s spine to beyond the surface of the abdomen . surgeons control the prior art instrument by holding a handle that is several inches from the working portion of the tool . the instrument shown in fig4 allows surgeons to control instruments with both of their hands . the novel instrument also allows surgeons to manipulate the tool closer to the working end of the tool . fig4 b is lateral view of the holding tool drawn in fig4 a and a curette . the novel holding tool may be used with other surgical instruments . fig4 c is a lateral view of a lateral view of the tip of an alternative embodiment of the holding tool drawn in fig4 b and a curette . enlargements on the shaft of the curette and the holding tool cooperate to improve the control of the instrument . fig4 d is a cross section of an alternative embodiment of the invention , wherein an enlargement 410 on the shaft of the reamer is contained within an enlarged area in the holding tool . fig4 e is a lateral view of an alternative embodiment of the holding tool drawn in fig4 d , a reamer bit , and a power tool . the holding tool drawn in fig4 d incorporates a sleeve . the sleeve protects the soft tissues from the rotating shaft of the reamer bit . the handle of the holding device is represented by the projection from the top of the device . fig4 f is a view of the end of the holding device drawn in fig4 e , a reamer bit , and an attachment 420 that may house a suction device , a scope , and / or a light . fig4 g is a lateral view of the tip of an alternative reamer bit which is blunt . fig5 a is an axial cross section of a disc 502 , two great vessels 504 , 506 and novel retractors 510 . the retractors may extend into the disc or outside the disc . the retractors hold the great vessel away from the anterior portion of the disc . fig5 b is an anterior view of the disc 502 , the great vessels 504 , 506 , and the embodiment of the retractor drawn in fig5 a . the retractors are holding the great vessels off of the anterior surface of the disc . fig5 c is an anterior view of the disc , the great vessels , the embodiment of the retractors drawn in fig5 b and novel guards 514 , 516 that are placed over the retractors . the modular guards lie along the inner sides of the great vessels . guards of other sizes and other shapes may be used . the guards 530 , 532 drawn in fig5 c are particularly suited to protect the great vessels lying adjacent to the l5 / s1 disc . fig5 d is an axial cross section of the disc , the great vessels , and the retractor drawn in fig5 c . the guard over the retractor on the right side of the drawing has been placed against the disc . the guard on the retractor drawn on the left side of the drawing has not been lowered to the disc yet . fig5 e is an anterior view of the disc , the great vessels , the retractors drawn in fig5 c , and guards with alternative shapes to the shapes drawn in fig5 c . the shape of the guards facilitates retraction of the great vessels at the l4 / l5 disc . fig5 f is a view of the top of an alternative embodiment of the guard drawn in fig5 c . the telescoping guard fits over the retractors drawn in fig5 c . fig6 a is a lateral view of novel platforms 602 , 604 , an or table 620 , and a patient 622 . the novel platforms lie over the patient . the platforms are attached to the side of the or table . fig6 b is view of the anterior side of the platforms drawn in fig6 a , and a patient . the patient is lying in a supine position . the platforms may be seen cephalad and caudal to an incision . surgeons may rest their hands on the platforms . much like a tripod used with guns or cameras , the platforms help surgeons avid undesired movements of their instruments . instruments with long shafts are particularly difficult to control . surgeons may also lever instruments against the stable platforms . surgeons are not able to lever their instruments against the soft tissues of the abdomen . fig6 c is an anterior view of the platform drawn in fig6 b and a surgical wound 660 . retractors 670 , 672 can be seen extending from the platform to the surgical wound . fig6 d is an anterior view of the platform drawn in fig6 b and a novel guide 680 attached to the platform . the guide is used to control an instrument . the circle 682 represents the cross section of an instrument . the guide limits the movements of the instrument . the instrument and the guide have features that control the depth the instrument is inserted into the wound , the excursion allowed by the instrument from the left to the right . for example , the platform and guide may be used with the reamer drawn in fig4 e . the guide controls the depth the reamer extends into the disc and how far the reamer may be directed to the left or right . fig6 e is an anterior view of the platform drawn in fig6 d and an alternative guide that controls the depth the instrument extends into the disc , how far the instrument may be moved to the left and the right , and how far the instrument may be moved towards the head and towards the feet . fig6 f is a lateral view of the platform drawn in fig6 b , a guide , and a reamer 688 . the platform and the guide are fixed in angles that facilitate use of the instrument . the platform and the guide may be fixed at other angles . this embodiment of the device facilitates use of instruments in the l5 / s1 disc . the l5 / s1 disc space is generally tilted forward with respect to the patient &# 39 ; s other discs . this embodiment of the invention also facilitates use of fluoroscopy during the procedure . the platforms , guides , and retractors are preferably made of radiolucent material . fig6 g is an anterior view of the platform drawn in fig6 b , retractors 690 , 691 , scope holders 692 , 693 , two scopes 694 , 695 , a surgical wound 696 and a monitor 697 . the scopes are reversibly held by attachments from the platforms . the scopes may be placed through separate surgical incisions . the platform holds the scopes more steadily than surgical assistants . in fact the platform may eliminate the need for surgical assistants for several types of surgical procedures . fig7 is a lateral view of a curette 702 and a handle 704 that is reversibly attached to the shaft of this or other surgical instruments . the handle gives surgeons more control of their instruments . fig8 a is the view of the top of a blade designed for use with a power tool . for example , the blade could be attached to an oscillating power tool . the cutting edge of the tool is represented by the dotted area of the drawing . rapid oscillation of the cutting tool reduces the pressure surgeons must apply the tool . prior art , non - power instruments such as curettes and elevators require a great deal of pressure to cut or separate the tissues . the reduced pressure required to operate the power tools decreases the risk of an instrument slipping if the resistance provided by the soft tissues drops suddenly . fig8 b is a view of the end of the cutting tool drawn in fig8 a . fig8 c is a view of the top of an alternative cutting bit . the bit has cutting surfaces along the sides of the bit . fig8 d is a view of the end of the cutting tool drawn in fig8 c . fig8 e is a view of the top of an alternative cutting bit . the bit has a cutting surface along one side of the bit . fig8 f is a view of the end of the cutting tool drawn in fig8 e . fig8 g is a view of the top of an alternative cutting bit . fig8 h is a view of the end of the cutting tool drawn in fig8 g . fig8 i is a view of the side of an alternative cutting tool . the cutting portion of the bit is at angle to the shaft of the tool . fig9 a is a lateral view of the spine 902 , an adr 904 , and an adr insertion tool 906 . a novel , wedge - shaped portion 910 of the tool holds the tdr in an exaggerated trapezoid shape . the trapezoid shape of the adr facilitates insertion of the adr into the prepared disc space . a portion of the wedge - shaped tool extends onto the vertebra or both vertebrae . the adr is impacted into the disc space . the adr moves off of the wedge as it moves into the disc space . the adr assumes a less trapezoid shape as it enters the disc space . the invention enables the adr to distract the disc space as the adr is inserted into the disc space . the tool that holds the adr may have scissor arm components . fig9 b is a lateral view of the spine , an adr and the wedge tool drawn in fig9 a . the adr has been partially inserted into the disc space . the portion of the tool that rests against the vertebra or vertebrae prevents the wedge tool from entering the disc space with the adr . the tool used to impact the adr was not drawn to show the wedge tool more clearly . fig9 c is a lateral view of the spine , an adr and the wedge tool drawn in fig9 b . the adr is positioned within the disc space . the adr was driven off of the wedge tool as it was impacted into the disc space . fig1 a is a drawing of a tool according to the invention which is articulated through a dial 1004 showing the degree of angulation between the handle 1006 and a shaft having a threaded tip 1008 . fig1 b shows the tool at and angle off center . the threaded tip 1008 may be connected to an adr or other implant , with the dial being used to indicate off - axis placement . if on - axis placement is preferred , the tool may be manipulated until a “ zero ” reading occurs . alternatively , if an off - axis manipulation is indicated , the surgeon need only read the value off of the dial on either side of center .
improved methods and apparatus render adr insertion safer and more precise . certain surgical instruments according to the invention include a level enabling a user to align the instrument for proper placement of a surgical implant . a different surgical instrument includes two or more scopes mounted relative to the instrument permitting a user to simultaneously view more than one side of the instrument . a device for use with a surgical instrument having a long shaft includes a holder that surrounds at least a portion of the shaft allowing a user to control the instrument with both hands . a further surgical instrument comprises a set of retractors and one or more guards placed over the retractors for protecting the great vessels , nerves or other delicate structures during a surgical procedure . surgical apparatus according to the invention comprises a platform mountable to an operating room table over a patient undergoing a surgical procedure , enabling a user to place their hands or attach an instrument while operating . different surgical instruments include an indicator showing angular displacement or a wedge - shaped portion used for disc distraction . also disclosed are blades designed for use with a power tool featuring a cutting edge configured such that rapid oscillation of the cutting tool reduces the pressure a user must apply the tool .