Abstract:
An adjustable reamer spindle is provided to aid a surgeon in controlling an instrument. The reamer spindle is easily disassembled for cleaning. The spindle has a repositionable handle, a locking ring, and an elastic device. The locking ring aids in holding the reamer spindle together. Removal of the locking ring against an elastic bias of a spring unfastens an end of the assembly in order to facilitate disassembly and/or cleaning. Adjustment of the position of the handle about the spindle enables the palm/grip of each hand to be changed in order to provide maximum control in different orientations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. Nos. 60/376,479, filed on Apr. 30, 2002; 60/384,186, filed on May 30, 2002; and 60/459,594, filed on Apr. 2, 2003. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to handles for reamers, and, more particularly, to adjustable handles for acetabular reamers that can be easily sterilized. 
     Complicated mechanical devices have crevasses and recesses that are difficult, if not almost impossible, to clean with ease. Devices that are not properly cleaned and sterilized contribute to the risk of disease transfer from patient to patient following the emergence of certain “prions” that are not killed by normal hospital sterilisation and need to be physically removed by washing/rinsing. 
     In GB PCT application no GB0202934A to Chana, entitled, Improved Surgical Devices and Methods of Use, the contents of which are incorporated by reference hereto, several reamer spindle designs are discussed. However, none includes a handle having the ability to be angularly repositioned about the axis of the housing and none uses a single spring to both lock the angularly repositionable handle in place and to lock the two housing portions in place. 
     What is needed therefore is a reamer spindle that is easily adjustable, disassemblable, and cleanable and which includes an easily repositionable handle using a mechanism requiring few components. 
     SUMMARY OF THE INVENTION 
     An adjustable reamer spindle is provided to aid the surgeon in controlling the instrument. Adjustment of the position of the handle axis of the spindle enables the axis through the palm/grip of each hand to change in order to provide maximum control in different orientations. The adjustment is desirable in order to accommodate operating on the left or right side of the patient, standing behind or in-front of the patient, or the use of a different surgical approach. Further, adjustment is important to accommodate the differing needs of surgeons who are naturally left or right handed. Thus, the comfort for holding and using the instrument is enhanced through adjustment. 
     In an objective of the invention, the handle can be easily cleaned, in that the design access to all surfaces such that they can be cleaned (i.e., one part covering another can be moved or removed to expose all surfaces). Further, the design enables the reduction in number of small radius internal corners, crevasses and small gaps and the absence of blind holes. 
     In another objective, a reamer handle is provided that is easy to disassemble and for which the disassembly is easy to learn. 
     In another object, the invention minimises the number of pieces and thus the risk that any individual part might be lost. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The attached drawings represent, by way of example, different embodiments of the subject of the invention. 
         FIG. 1  is a side view of the reamer spindle of the present invention. 
         FIG. 2  is a top view of the reamer spindle of the present invention. 
         FIG. 3  is a section view taken along line  3 - 3  shown in  FIG. 2 . 
         FIG. 4  is a plan view showing a traditional reamer spindle of the prior art being used in a minimally invasive approach for reaming the acetabular socket. 
         FIG. 5  is a plan view showing the reamer spindle of the present invention being used in a minimally invasive approach for reaming the acetabular socket. 
         FIG. 6  is an exploded assembly of an alternative embodiment of the present invention. 
         FIG. 7  is an alternative shape housing of the alternative embodiment shown in  FIG. 6   
         FIG. 8  is a perspective view of an alternate embodiment of the invention having a repositionable handle. 
         FIG. 9A  is an exploded view of the alternate embodiment of  FIG. 8 . 
         FIG. 9B  is a close up of a portion of the exploded view of the alternate embodiment of  FIG. 8 . 
         FIG. 9C  is a cross-sectional view of the adjustable handle portion of the alternate embodiment of  FIG. 8 . 
         FIG. 10  is a perspective view of key components of the alternate embodiment of  FIG. 8 . 
         FIG. 11  is a plan view of a surgical reamer kit of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The reamer spindle  115  shown in  FIGS. 1-3 , and  5  consists of a drive fitting  104 , which is adapted to be joined to a rotary power source used to drive the shaft  107  of the reamer spindle  115 . The shaft  107  is mounted to a reamer holding mechanism  120 . The reamer holding mechanism  120  can be selected from a variety of mechanisms useful for capturing and holding a surgical reamer  1  during an orthopedic surgical procedure. It is clear that many different mechanisms exist which would be useful for this task, however the present inventors have selected the preferred bayonet style mechanism  120  for purpose of example. The reamer holding mechanism  120  comprises a slide  106  carrying a pin component  111  of the reamer holding mechanism  120 . The pin  111  works cooperatively with the catch  110  located in the head  108  to form the bayonet for capturing different size reamers  1  while allowing their easy release for size interchangeability and cleaning. The reamers  1  selected for use with the reamer spindle  115  can be shaped and sized for cutting different osseous sites within the body. It is widely known that reamers can be designed to cut the patella in a knee or the glenoid in a shoulder or the socket  45  in an acetabulum  40  as shown in  FIGS. 4-5 . 
     Referring to  FIGS. 4-5 , the reamer spindle  115  of the present invention and the spindle  15  of the prior art invention are shown passing through a miniature incision  35  in the patient&#39;s skin  30 . In  FIG. 4 , the reamer spindle  15  is shown approaching the acetabulum  40  in a preferred orientation for reaming the socket  45 . The difficulty with the prior art spindle  15  is shown as the shaft  3  impinges on the miniature incision  35  at edge of the incision  37 . The current surgical protocols are being pushed to the limits and the incision sizes are being reduced in the hopes of increasing the patient&#39;s speed to recovery. In some cases surgeons are using a two-incision approach, one to reach the acetabulum and the other to reach the femur. Depending on the situation, either the one incision or the two incision technique results in less trauma to the patient, thus requiring the instruments to be flexible and more optimally designed to make up for the lack of operating space. 
     The reamer  115  of  FIG. 5  shows a new reamer spindle  115 , which has a bent housing  113  containing the drive shaft  107 . The drive shaft  107  can be selected from a variety of current torque transmitting mechanisms or devices including a Nickel Titanium shaft, a flexible round or flat wire wound cable, a series of gear driven shafts, or a series of shafts interconnected by universal joints. The drive shaft  107  can also be selected from any torque transmission mechanism or device deemed appropriate for the application. The drive shaft  107  can be held to the housing  113  with an optional series of bearings  118 - 119  which keep the drive shafts from bearing against/riding on the inside of the housing  113  and act as a shield to protect the inner housing from blood. Other means for holding the shaft to the housing would be acceptable. The most important feature of the drive shaft  107  is that it conforms to the selected housing  113  and sufficiently supplies torque to the cutter  1 . 
     The housing  113  is formed from cannulated material and the drive end  104  is substantially collinear with the holding mechanism  120  along axis  116 . Referring now to  FIG. 8  et seq., alternatively, the drive end  104  could be situated along an axis parallel or offset to axis  116 . The bends in the housing are optimally placed at critical locations to pass through the miniature incision without impinging on the skin  30  at location  37  while still maintaining the same surgical protocol. The drive end  104  and the holding mechanism  120  should be in line or on parallel axes so that the applied force  130  results in an axial motion  140 . This allows the surgeon to maintain the existing technique because inherently reamer spindle  15  in  FIG. 4  would give the same result since it has a straight drive shaft  3 . Thus, the surgeon is allowed to apply a load directly along the path of reaming. 
     Referring now to  FIG. 6 , an alternative embodiment is shown. Similar to  FIGS. 1-3  and  5 , the reamer spindle  215  has a drive fitting  204 , which is adapted to be joined to a rotary power source used to drive the shaft  207  of the reamer spindle  215 . The drive shaft  207  can be selected from a variety of current torque transmitting mechanisms or devices including a Nickel Titanium shaft, a flexible round or flat wire wound cable, a series of gear driven shafts, or a series of linkages  208  interconnected by universal joints  209 . The drive shaft  207  can also be selected from any torque transmission mechanism or device deemed appropriate for the application. In this embodiment, the shaft  207  is constructed from a series of linkages  208  containing universal joints  209  and bearing members  218 . 
     The reamer holding mechanism  220  is preferably a bayonet fitting with a slide  206  carrying a pin component  211  of the reamer holding mechanism  220 . The pin  211  works cooperatively with the catch  210  located in the head  208  to form the bayonet for capturing different size reamers while allowing their easy release for size interchangeability and cleaning. The drive shaft  207  is set in housing members  213  and  214 , which are separable for cleaning. 
     There are many ways of connecting the housing members  213  and  214  together. For example, the shaft  207  can include a capture mechanism  247  which is adapted to receive the front ends of the housing members  213  and  214  aligning each with one another and encapsulating the drive shaft  107  to protect the patient&#39;s skin from contacting the torque transmitting shaft  207  during operation. Once the housing members  213  and  214  are aligned, a locking mechanism  250  comprised of a ring  255  and a catch  260 , which is located in the housing member  213 , interact with one another to retain the housing members  213  and  214  in a closed fashion. As with the embodiment described in  FIGS. 1-3 , and  5 , it is preferable to have the drive end  204  substantially collinear with the holding mechanism  220  along axis  216 . The housing members  213  and  214  are shown preferably in a bent configuration; however, the reamer spindle  215  with a separable housing includes the option of a straight configuration, as is the case with housing members  313  and  314 , shown in  FIG. 7 , having no bend. 
     Referring now to  FIG. 8 , in another embodiment  315 , the drive end  404  is situated along an axis parallel and offset to axis  416 . Further, a repositionable handle  500  doubles as a component of the capture mechanism  447  in order to hold the two housing members  413  and  414  together. 
     The capture mechanism  447  slides over the front ends  448  of the housing members  413  and  414 , aligning each with one another and thus encapsulating the drive shaft  107  in order to protect the patient&#39;s skin from contacting the torque transmitting shaft  107  after being assembled. 
       FIGS. 9A ,  9 B and  9 C more clearly show how the housing members  413  and  414  are aligned and locked in place. The housing members  413  and  414  are oriented with respect to each other when a locking sleeve  502   a  (having an internal diameter larger than the outside diameter of the housing members) slides over them, abutting against a bend  480  in the housing members. Thin, annular Teflon sleeves (not shown) are disposed between the housing members  413  and  414  and the locking sleeve  502   a  to facilitate disassembly. A forward mouth section  502   b  of the locking sleeve  502   a  cradles the bend  480  of the housing members  413  and  414  so as to prevent relative rotation of the locking sleeve and housing members. At the front  448 , the capture mechanism  447  has a locking device  450  which includes an annular sleeve  482  onto which the handle  500  is affixed. The sleeve  482   a  includes a face  482   b  having recesses  482   c  (shown in  FIG. 9C ) into which pins  484 , fixed to a shoulder  502   c  of the locking sleeve  502 , are received in order to torsionally rigidly hold the handle  500  in any one of eight positions, according to the preference of the surgeon. A spring  486  biases the annular sleeve  482   a  into engagement with the pins  484  via, on the one hand, applying spring pressure against an internal shoulder  482   c  (shown in  FIG. 9C ) in the annular sleeve  482   a  and, on the other hand, reacting against a locking ring  455 . The locking ring  455  includes pins  490  which are affixed thereto and which enter into bayonet slots  492  in the locking sleeve  502  in order to hold the locking device  450  on the end of the locking sleeve and thus the capture mechanism  447  together. The housing members  413  and  414  are held together via the pins  490  which engage the bayonet slots  492  in each of the housing members  413  and  414  (best shown in  FIG. 10  in which the annular sleeve  502 , the spring  486  and the locking sleeve  502  are removed for clarity). The pins  490  of the locking ring  455  and a catch  260  interact with one another to retain the housing members  413  and  414  in a closed fashion while concurrently biasing the spring  486  so as to engage the annular sleeve  482   a  (and thus the handle  500 ) with the pins  484 . Further, sufficient play in the axial movement of the annular sleeve  482   a  is permitted to enable the surgeon to selectively disengage the sleeve from the pins  484  so as to reposition the handle about the locking sleeve  502   a  in any one of the eight angular positions of the handle  500 , while avoiding disassembly of the spindle  115 . 
     Referring now to  FIG. 11 , collectively, these different types of housing members  213 - 214 ,  313 - 314 , and  413 - 414  can be offered as a kit  600  having a selection of different sized reamer housings  113  together with an impactor  602 , acetabular implants (not shown), femoral hip prostheses  604 , and acetabular cup prostheses ( 606 ), the selection of different reamer housing configurations allowing the surgeon to select between a bent, offset configuration or a straight configuration of the reamer spindle  115 ,  215 , and  315  depending on the surgeons approach, which may vary during the same operation or between different patients. 
     Multiple variations and modifications are possible in the embodiments of the invention described here. Although certain illustrative embodiments of the invention have been shown and described here, a wide range of modifications, changes, and substitutions is contemplated in the foregoing disclosure. In some instances, some features of the present invention may be employed without a corresponding use of the other features. Accordingly, it is appropriate that the foregoing description be construed broadly and understood as being given by way of illustration and example only, the spirit and scope of the invention being limited only by the appended claims.