Cannula and sizing insertion method

Abstract

A relatively inexpensive cannula is sized by including indica on a cannulated dilator that is used to measure the depth of a body cavity, and in one embodiment with the use of a cuttable fixture inserted into an initially enlarged dilator retractor made from a cuttable material the excess of the dilator retractor is snipped by a commercial cutter. A tool engaging the end of the cannulated dilator provides leverage on the cannulated dilator for rotation as it is forced into the body cavity, a pusher tool provides leverage on the dilator retractor for inserting the dilator retractor into the body cavity. A clamp that fits the top of the dilator retractor serves to support the dilator retractor through an arm to a rigid structure. In an alternate embodiment one of a series of sized dilator retractors are selected commensurate with the measurement attained by the scaled cannulated dilator.

I claim: 
     
       1. A cannulated dilator having an outer surface, said cannulated dilator for insertion into an access hole formed in a patient for stretching the tissue adjacent to the access hole so as to enlarge the same, said cannulated dilator having an elongated tubular body, a beveled portion at the distal end thereof, the improvement comprising indicia on the side outer surface of the cannulated dilator for measuring the depth of the access hole, said cannulated dilator having a proximal end and a tool engagement portion formed thereon, in combination with a tool having an engagement portion complementing the tool engagement portion of the cannulated dilator adapted to fit thereon for rotation and applying leverage on said cannulated dilator for insertion thereof into the access hole and a cannula for fitting into said access hole for permitting the performance of a medical procedure after the cannulated dilator has been removed. 
     
     
       2. A cannulated dilator having an outer surface, said cannulated dilator for insertion into an access hole formed in the body of a patient for stretching the tissue adjacent the access hole and for enlarging the same, said cannulated dilator having an elongated tubular body, a beveled portion at the distal end thereof, the improvement comprising indicia on the side outer surface of the cannulated dilator for measuring the depth of the access hole, said cannulated dilator having a pair of circumferentially spaced tabs extending radially from the proximal end, in combination with a tool having a rectangularly shaped planar body, a central bore formed intermediate the ends thereof, an enlarged diameter recess extending from one face into said planar body and being concentric with said central bore but spaced from the opposite face thereof to define a shoulder, said tabs complementing recesses formed in said planar body adjacent to said enlarged diameter recess, whereby the cannulated dilator fits into said tool and said cannulated dilator engages said shoulder to permit the user to insert said cannulated dilator into said access hole and rotate same as it progresses into said access hole and a cannula for insertion into said access hole to permit a surgical procedure after the cannulated dilator has been removed. 
     
     
       3. The combination of a cannulated dilator and a dilator retractor wherein said cannulated dilator includes indicia for measuring the depth of an access hole formed in a patient for medical procedure and said dilator retractor being made from a cuttable material and being dimensioned larger in length than is anticipated of any depth of said access hole of the body of any patient that is anticipated in the medical procedure, the dilator retractor being cuttable commensurate with the depth of said access hole as measured by said cannulated dilator for sizing said dilator retractor to a length that is shorter than the original length of the dilator retractor prior to being inserted into the access hole so as to be utilized for performing the medical procedure whereby said dilator retractor is sized for the anatomy of the patient. 
     
     
       4. The combination of a cannulated dilator and a dilator retractor as claimed in  claim 3  wherein said dilator retractor is made from a plastic material. 
     
     
       5. The combination of a cannulated dilator and a dilator retractor as claimed in  claim 4  wherein said dilator retractor is made from a transparent material. 
     
     
       6. The combination of a cannulated dilator and dilator retractor as claimed in  claim 3  including an annular clamp, said clamp being dimensioned to fit said dilator retractor and means including a bracket extending from said annular clamp adapted to support the dilator retractor to a rigid member. 
     
     
       7. The combination of a cannulated dilator and dilator retractor as claimed in  claim 6  wherein said clamp is split through a portion thereof to define a gap between the ends adjacent the split, an adjustment for enlarging or decreasing said gap and the inner diameter portion surrounding the dilator retractor for securing said annular clamp to the dilator retractor and including means adapted to support the dilator retractor to a rigid member. 
     
     
       8. The combination of a cannulated dilator and dilator retractor as claimed in  claim 6  including an elongated fixture having a circular cross section and made from a cuttable plastic material, and means to cut said dilator retractor an amount commensurate with the measurement attained by said cannulated retractor and the width of said annular clamp. 
     
     
       9. The combination of a cannulated dilator and dilator retractor as claimed in  claim 8  wherein said elongated fixture includes a series of axially spaced grooves spaced a predetermined amount, said dilator retractor being transparent and fitting over said elongated fixture for the spaced grooves to be visible wherein the selection of said annular grooves determines the length of the dilator retractor to be cut. 
     
     
       10. The combination of a cannulated dilator and dilator retractor as claimed in  claim 3  including a pusher tool having an elongated circular body, a central bore having a dimension to complement the outer diameter of said cannulated dilator, and a bottom surface overlying the end of said dilator retractor so that when said pusher tool is pushed into the body cavity the dilator retractor is forced into the body cavity and the central bore slides over said cannulated dilator. 
     
     
       11. The combination of a cannulated dilator and dilator retractor as claimed in  claim 10  wherein said pusher tool is integral with said elongated fixture. 
     
     
       12. The combination of a cannulated dilator and dilator retractor, said cannulated dilator being in the series of the last cannulated dilator for enlarging the access hole in the body of a patient, at least one of said cannulated dilators having an elongated body, indicia on said elongated body indicative of a measurement of depth for measuring the depth of the access hole, said dilator retractor including a series of dilator retractors each having different lengths, whereby the dilator retractor for use in the access hole is selected from said series of dilator retractors that is commensurate with the measurement of said cannula(d dilator as obtained from said indicia when inserted into said access hole for defining a working space for performing a medical procedure when the cannulated dilator has been removed. 
     
     
       13. The method of sizing the length of a cannula to fit the depth of an access hole formed in the body of a patient including the steps of:
 i. providing a cannula that is oversized in length;   ii. providing a cannulated dilator that is in the last of a series of cannulated dilators used for enlarging the access hole with indicia of a scale for measuring a length;   iii. measuring the depth of the access hole by inserting the cannulated dilator obtained in the step of providing a cannulated dilator into the access hole to ascertain the depth;   iv. cutting the cannula to the size obtained in the step of measuring before being inserted into the access hole; and   v. inserting the cannula obtained in the step of cutting into the access hole over the cannulated dilator and removing the cannulated dilator to define a working space to perform a medical procedure.   
     
     
       14. The method as claimed in  claim 13  including the step of providing a template made from a cuttable material that is dimensioned to fit into the cannula;
 i. inserting the template into the cannula; 
 ii. cutting the cannula and template at the length commensurate with the access hole. 
 
     
     
       15. The method as claimed in  claim 14  including the provision of including markings on said template graduated to a scale commensurate with the scale of the indicia on the cannulated dilator; and the cannula being transparent so that the scale on the fixture is visible. 
     
     
       16. The method as claimed in  claim 14  including a clamp to fit the end of the cannula; cutting in the step of cutting the cannula to a length that includes the width of the clamp. 
     
     
       17. The method as claimed in  claim 14  including the step of providing a tool for engaging the proximal end of the cannulated dilator and inserting the cannulated dilator by pushing and turning the tool. 
     
     
       18. The method as claimed in  claim 14  including the step of providing a tool for engaging said cannula for pushing said cannula into the access hole. 
     
     
       19. The method of sizing the length of a cannula to fit the depth of an access hole formed in the body of a patient including the steps of:
 i. providing a series of different length cannulas;   ii. providing a cannulated dilator with indicia of a scale for measuring a length;   iii. measuring the depth of the access hole by inserting the cannulated dilator into the access hole to ascertain the depth;   iv. selecting from said different length cannulas obtained in the step of providing a series of different length cannulas the length correlating to the length obtained in the step of measuring before inserting said selected cannula; and   v. inserting said the cannula obtained in the step of selecting from said different length cannulas into said access hole for defining a working chamber for performing the medical procedure.   
     
     
       20. The combination of a cannulated dilator and dilator retractor as claimed in  claim 12  including an annular clamp, said clamp being dimensioned to fit any of said dilator retractor from said series of said dilator retractors and a bracket extending from said annular clamp adapted to support the dilator retractor to a rigid member. 
     
     
       21. The combination of a cannulated dilator and dilator retractor as claimed in  claim 12  wherein each of said cannulated dilator has a proximal end and a tool engagement portion formed thereon, a tool having an engagement portion complementing the tool engagement portion of the cannulated dilator adapted to fit thereon for rotation and applying leverage on said cannulated dilator for insertion thereof into the body cavity. 
     
     
       22. The combination of a cannulated dilator and dilator retractor, said cannulated dilator having an elongated body, said cannulated dilator for obtaining the measurement of depth of an access hole formed in a body, said dilator retractor including a series of dilator retractors having different lengths, whereby the dilator retractor for use in the access hole is selected from said series of dilator retractors that is commensurate with the measurement obtained from said cannulated dilator when extended into said access hole. 
     
     
       23. The combination of a cannulated dilator and dilator retractor as claimed in  claim 12  wherein said dilator retractor is made form a plastic material. 
     
     
       24. The combination of a cannulated dilator and dilator retractor as claimed in  claim 23  wherein said dilator retractr is made form a transparent material. 
     
     
       25. A method of surgically creating a working channel in a patient through which to conduct a surgical procedure, comprising:
 sequentially inserting a series of dilators into a patient to form an access hole, at least one of the dilators having indicia formed thereon for measuring a depth of the access hole;   inserting an access instrument over the dilators to position the access instrument into the access hole, the access instrument having a length that is equal to the sum of (i) the measured depth of the access hole and (ii) a length of a body disposed at a proximal end of the access instrument, the body having a width greater than a width of the access hole; and   removing the dilators from the access instrument to provide a working channel through the access instrument.   
     
     
       26. The method of claim 25, wherein, prior to the step of inserting the access instrument over the dilators, a length of the access instrument is adjusted to have a length that is equal to the sum of (i) the measured depth of the access hole and (ii) the length of the body. 
     
     
       27. The method of claim 25, wherein the access instrument is selected from a series of access instruments having different lengths. 
     
     
       28. The method of claim 25, wherein the body extends from a proximal-most end to a distal-most end that abuts the access hole, the proximal-most and distal-most ends having a width greater than the width of the access hole. 
     
     
       29. The method of claim 25, wherein the access hole extends to a vertebral disc space. 
     
     
       30. The method of claim 25, wherein the dilators are cannulated and are inserted over a guidewire. 
     
     
       31. The method of claim 25, wherein the body extends along a skin surface of the patient. 
     
     
       32. The method of claim 25, wherein the step of forming the access hole in the patient comprises inserting a guide wire into the patient and sequentially inserting the series of dilators over the guidewire to create the access hole. 
     
     
       33. The method of claim 25, further comprising selecting one of a plurality of possible lengths of the access instrument based on the measured depth of the access hole.