Cannulotome

Abstract

Systems and methods for treating spinal stenosis include endoscopic access devices and bone removal devices used to perform a foraminotomy or other bone removal procedures. A bone removal device includes a cannulotome with an endoscopic imaging lumen. Optionally, an endoscope retaining device can be used to facilitate advancement of the endoscope through the cannulotome.

1 . A system for spinal surgery comprising:
 a tissue removal device comprising a proximal handle, an elongate shaft with a lumen terminating at a distal opening, the distal opening comprising a perimeter with a tapered protrusion, wherein the tapered protrusion comprises a proximal base and a distal cutting edge, and wherein at least one-quarter of the perimeter lies at or proximal to the base; and   an endoscope retaining device comprising an elongate support structure configured to receive an endoscope, wherein the endoscope retaining device is configured to be coupled to the proximal handle of the tissue removal device in a predetermined radial orientation.   
     
     
         2 . The system of  claim 1 , wherein the cutting edge comprises a notch, wherein the proximal-most portion of the notch is distal to the proximal base of the tapered protrusion. 
     
     
         3 . The system of  claim 1 , wherein the tapered protrusion comprises an exterior surface and an interior surface that converge at the cutting edge, and wherein the taper angle between the exterior and interior surface is 20° or less. 
     
     
         4 . The system of  claim 3 , wherein the tapered protrusion comprises an exterior surface and an interior surface that converge at the cutting edge, and wherein the taper angle between the exterior and interior surface is 10° or less. 
     
     
         5 . The system of  claim 3 , wherein the exterior surface of the tapered protrusion comprises one or more recesses configured to retain a therapeutic substance therein. 
     
     
         6 . The system of  claim 5 , wherein the one or more recesses have a circular shape or rectangular shape. 
     
     
         7 . The system of  claim 5 , wherein the therapeutic agent is bone wax. 
     
     
         8 . The system of  claim 3 , wherein the interior surface of the tapered protrusion comprises one or more orientation markings. 
     
     
         9 . The system of  claim 1 , further comprising an endoscope configured to be coupled to the endoscope retaining device. 
     
     
         10 . The system of  claim 1 , further comprising a cannula, wherein the tissue removal device is configured to extend through the cannula. 
     
     
         11 . The system of  claim 10 , wherein the cannula is a retractor cannula comprising one or two distal jaws, wherein the tissue removal device is configured to extend through the retractor cannula. 
     
     
         12 . The system of  claim 1 , wherein the endoscope retaining device further comprises a proximal handle attached to a proximal portion of the elongate support structure, and a distal securing element configured to partially enclose a distal circumferential surface of an endoscope in a predetermined rotational alignment, while partially exposing the distal circumferential surface. 
     
     
         13 . The system of  claim 12 , wherein the endoscope retaining device further comprises an outer sheath, wherein the support structure is at least partially enclosed within the outer sheath. 
     
     
         14 . The system of  claim 12 , wherein the elongate support structure comprises one or more tubular channels configured to transport fluid along the support structure, wherein each tubular channel comprises an external surf ace and an internal surf ace. 
     
     
         15 . The system of  claim 12 , wherein a distal securing structure comprises one or more retention tabs configured to engage the distal portion of an endoscope. 
     
     
         16 . The system of  claim 12 , wherein support structure comprises a longitudinal slot configured to axially provide a predetermined range of relative longitudinal movement between an endoscope and the support structure. 
     
     
         17 . The system of  claim 12 , wherein the support structure further comprises an arched protruding structure that extends along a longitudinal length of the support structure, the arched structure configured to position the support structure within the lumen of the cannulotome shaft. 
     
     
         18 . The system of  claim 12 , wherein a distal portion of the support structure comprises a bend region, wherein the bend region has a first stressed straight configuration and a second relaxed bent configuration. 
     
     
         19 . The system of  claim 18 , further comprising a mandrel insertable through the endoscope retaining device and along the support structure, wherein in the first straight configuration, the mandrel is in a position distal to the bend region, and in the second bent configuration, the mandrel is in a position proximal to the bend region. 
     
     
         20 . The system of  claim 18 , further comprising a grasper tool insertable through the endoscope retaining device and along the support structure. 
     
     
         21 . The system of  claim 19 , wherein the tissue removal device handle comprises a slot and the endoscope retaining device handle comprises one or more flanges, and wherein the tissue removal device handle is configured to retain the endoscope retaining device handle such that the flanges are aligned along the slot. 
     
     
         22 . The system of  claim 21 , wherein the tissue removal device handle is configured to retain the endoscope retaining device by friction-fit. 
     
     
         23 . The system of  claim 21 , wherein the endoscope retaining device handle is configured to engage an endoscope using a latch mechanism. 
     
     
         24 . The system of  claim 21 , further comprising an endoscope attachment tab configured to releasably engage with a length of an endoscope cable, and wherein the endoscope retaining device handle is configured to engage the endoscope attachment tab. 
     
     
         25 . The system of  claim 21 , wherein the endoscope retaining device handle is configured to engage an endoscope using a spring-based mechanism. 
     
     
         26 . The system of  claim 21 , further comprising a grasping device configured to be inserted through the outer sheath of the endoscope retaining device. 
     
     
         27 . An endoscope stabilization system comprising:
 an endoscope; and   an endoscope retaining device comprising a proximal handle and an elongate support structure attached to the handle, wherein the support structure comprises an elongate structure with retention protrusions configured to releasably secure a distal portion of the endoscope and one or more tubular structures along a side of the elongate structure configured for transporting fluid along the endoscope retaining device.   
     
     
         28 . The system of  claim 27 , wherein the endoscope retaining device further comprises a tube that is attached to the proximal handle, wherein the support structure is at least partially enclosed in a lumen of the tube. 
     
     
         29 . The system of  claim 27 , wherein the endoscope retaining device is configured to retain the endoscope such that the endoscope is axially aligned with the support structure. 
     
     
         30 . The system of  claim 29 , wherein the endoscope retaining device and the endoscope comprises corresponding structures such that alignment of the corresponding structures axially aligns the endoscope with the support structure. 
     
     
         31 . The system of  claim 30 , wherein the endoscope comprises a protrusion and the elongate structure comprises a longitudinal slot such that insertion of the protrusion within the slot axially aligns the protrusions with the support structure. 
     
     
         32 . The system of  claim 27 , wherein a distal portion of the support structure comprises an arched protruding structure that extends along a longitudinal length of the support structure, the arched structure configured to position the support structure within a lumen of a tube. 
     
     
         33 . The system of  claim 27 , wherein a distal portion of the support structure comprises a bend region, wherein the bend region has a first stressed straight configuration and a second relaxed bent configuration. 
     
     
         34 . The system of  claim 33 , further comprising a mandrel insertable through the endoscope retaining device and along the support structure, wherein in the first straight configuration, the mandrel is in a position distal to the bend region, and in the second bent configuration, the mandrel is in a position proximal to the bend region. 
     
     
         35 . The system of  claim 27 , wherein the support structure comprises two or more proximal tabs, wherein the proximal tabs correspond to two or more recesses in the proximal handle of the endoscope retaining device, and wherein the support structure is engaged to the proximal handle of the endoscope retaining device by engaging the proximal tabs within the recesses. 
     
     
         36 . The system of  claim 33 , wherein the proximal handle is configured to engage the endoscope using a latch mechanism. 
     
     
         37 . The system of  claim 27 , further comprising an endoscope attachment tab configured to releasably engage with a length of an endoscope cable, and wherein the proximal handle is configured to engage the endoscope attachment tab. 
     
     
         38 . The system of  claim 27 , wherein the endoscope retaining device handle is configured to engage the endoscope using a spring-based mechanism. 
     
     
         39 . The system of  claim 27 , further comprising an introducer cannula. 
     
     
         40 . A method for spinal surgery comprising:
 inserting an introducer cannula into a target spine region;   advancing an endoscope assembly comprising an endoscope coupled to an endoscope retaining device through the lumen of the introducer cannula, wherein the endoscope retaining device comprises a channel therethrough;   withdrawing the endoscope assembly;   advancing a cannulotome with a proximal handle, an elongate shaft with a lumen therethrough, and a tapered cutter at the distal end of the shaft through the lumen of the introducer cannula;   applying force to the cannulotome to remove bony or calcified tissue while simultaneously visualizing the removal of the tissue through a lumen of the cannulotome;   drawing the tissue up through the lumen of the cannulotome shaft; and   withdrawing the cannulotome.   
     
     
         41 . The method of  claim 40 , further comprising infusing fluid through the channel of the endoscope retaining device to the target spine region. 
     
     
         42 . The method of  claim 40 , further comprising advancing the endoscope assembly through the cannulotome shaft lumen. 
     
     
         43 . The method of  claim 40 , further comprising lubricating the lumen of the introducer cannula. 
     
     
         44 . The method of  claim 40 , wherein applying force to the cannulotome comprises tapping the cannulotome handle with a mallet. 
     
     
         45 . A method for spinal surgery comprising:
 inserting a cannulotome with a proximal handle, an elongate shaft with a lumen therethrough, and a tapered cutter at the distal end of the shaft through an introducer cannula;   advancing an endoscope assembly comprising an endoscope coupled to an endoscope retaining device through the lumen of the cannulotome, wherein the endoscope   retaining device comprises a channel therethrough;   advancing the introducer cannula to a target spine region; and   applying force to the cannulotome to remove bony or calcified tissue while simultaneously visualizing the removal of the tissue through a lumen of the cannulotome.   
     
     
         46 . The method of  claim 45 , further comprising infusing fluid through the channel of the endoscope retaining device to the target spine region. 
     
     
         47 . The method of  claim 45 , wherein the distal cutter of the cannulotome comprises orientation markings, and wherein advancing the endoscope assembly comprises positioning the endoscope assembly according to the orientation markings. 
     
     
         48 . The method of  claim 45 , wherein applying force to the cannulotome comprises tapping the cannulotome handle with a mallet. 
     
     
         49 . The method of  claim 48 , further comprising acquiring endoscope images during or immediately after the application of force to the cannulotome. 
     
     
         50 . The method of  claim 49 , further comprising rotating the cannulotome within the introducer cannula to contact a different tissue region. 
     
     
         51 . The method of  claim 45 , further comprising drawing up the removed tissue through the cannulotome shaft lumen using a grasping tool. 
     
     
         52 . The method of  claim 51 , further comprising discarding the endoscope retaining device at the end of the procedure.