Methods and devices for cooling spinal tissue

Abstract

Methods, systems, and devices are disclosed for cooling tissue, and in particular for applying therapeutic hypothermia to the spinal canal, tissue disposed within the spinal canal, and nerve roots extending from the spinal canal. Bone screws, intervertebral implants, stabilization rods, spinous process spacers, and other devices are described which define a chamber through which a chilled fluid, expandable gas, or other coolant means can be circulated, delivered, or activated to cool adjacent tissue. The degree of cooling can be regulated using a controller, which can be configured to increase or decrease the cooling effect based on any of a variety of measured or predicted physiological or thermodynamic properties. Methods are disclosed for implanting cooling instruments and for carrying out various treatment regimens that involve cooling tissue using such instruments.

What is claimed is: 
     
         1 - 78 . (canceled) 
     
     
         79 . A method for cooling tissue, comprising:
 implanting a disc replacement member in a disc space between a first vertebra and a second vertebra such that the disc replacement member stabilizes the first and second vertebrae; and   cooling the disc replacement member to cool tissue in a spinal canal adjacent to the disc space.   
     
     
         80 . The method of  claim 79 , wherein cooling the disc replacement member comprises delivering a pressurized gas to a chamber formed within the disc replacement member. 
     
     
         81 . The method of  claim 79 , wherein cooling the disc replacement member comprises delivering a cooled fluid to a chamber formed within the disc replacement member and withdrawing the cooled fluid from the chamber through an exhaust conduit. 
     
     
         82 . The method of  claim 79 , further comprising dynamically controlling the cooling of the disc replacement member such that a degree of cooling can be increased and decreased. 
     
     
         83 . The method of  claim 82 , wherein said controlling comprises increasing or decreasing at least one of a rate of fluid flow through the disc replacement member and a temperature of fluid supplied to the disc replacement member based on one or more measured characteristics. 
     
     
         84 . The method of  claim 83 , wherein the one or more measured characteristics include at least one of a physiological characteristic and a temperature of the disc replacement member. 
     
     
         85 . The method of  claim 83 , further comprising, prior to or during said controlling, measuring the one or more measured characteristics using a temperature sensor. 
     
     
         86 . The method of  claim 79 , wherein cooling the disc replacement member reduces a temperature of the tissue by at least about 2 degrees C. 
     
     
         87 . The method of  claim 79 , further comprising closing a tissue opening through which the disc replacement member was implanted with the disc replacement member remaining in the disc space. 
     
     
         88 . The method of  claim 79 , further comprising separating at least one conduit from the disc replacement member. 
     
     
         89 . The method of  claim 88 , wherein separating the at least one conduit comprises deflating a coupling balloon. 
     
     
         90 . An apparatus for cooling a spinal canal, comprising:
 an implant having a posterior end and an anterior end and defining a chamber therein, the implant being configured for placement within a disc space between adjacent vertebrae;   a delivery conduit coupled to the implant and in fluid communication with the chamber, the delivery conduit being configured to supply a cooling medium to the chamber; and   an exhaust conduit coupled to the implant and in fluid communication with the chamber.   
     
     
         91 . The apparatus of  claim 90 , further comprising an expansion nozzle disposed at a distal end of the delivery conduit. 
     
     
         92 . The apparatus of  claim 90 , wherein the delivery conduit terminates at a location adjacent to the posterior end of the implant and the exhaust conduit terminates at a location adjacent to the anterior end of the implant. 
     
     
         93 . The apparatus of  claim 90 , wherein the chamber comprises a fluid lumen having a first end coupled to the delivery conduit and a second end coupled to the exhaust conduit. 
     
     
         94 . The apparatus of  claim 93 , wherein the fluid lumen is at least one of coiled and snaked. 
     
     
         95 . The apparatus of  claim 90 , further comprising a Peltier device disposed within the chamber and a controller configured to adjust an amount of current supplied to the Peltier device. 
     
     
         96 . The apparatus of  claim 95 , wherein the delivery conduit comprises an electrical lead for supplying current to the Peltier device and the exhaust conduit is configured to remove heat generated by the Peltier device from the chamber. 
     
     
         97 . The apparatus of  claim 90 , further comprising a coolant source configured to provide the cooling medium to the delivery conduit. 
     
     
         98 . The apparatus of  claim 97 , further comprising a controller configured to adjust at least one of a rate at which the cooling medium is provided to the delivery conduit and a temperature of the cooling medium. 
     
     
         99 . The apparatus of  claim 98 , further comprising at least one sensor configured to generate an output indicative of at least one of a physiological condition and a temperature of the implant, wherein the controller is configured to adjust the rate at which the cooling medium is provided to the delivery conduit based on the output of the sensor. 
     
     
         100 . The apparatus of  claim 90 , further comprising a coupling balloon having at least an inflated configuration in which the balloon forms an interference fit to couple the delivery conduit and the exhaust conduit to the implant and a deflated configuration in which the delivery conduit and the exhaust conduit are separable from the implant. 
     
     
         101 . The apparatus of  claim 100 , wherein application of the cooling medium to the delivery conduit is effective to maintain the balloon in the inflated configuration and evacuation of the cooling medium from the delivery conduit is effective to transition the balloon from the inflated configuration to the deflated configuration. 
     
     
         102 . The apparatus of  claim 90 , further comprising at least one dividing wall extending into the chamber, the dividing wall being configured to direct the cooling medium through the chamber. 
     
     
         103 . The apparatus of  claim 102 , wherein the delivery conduit is coupled to the chamber on a first side of the dividing wall and the exhaust conduit is coupled to the chamber on a second side of the dividing wall. 
     
     
         104 . The apparatus of  claim 90 , wherein at least a portion of a posterior surface of the implant has an increased thermal conductivity relative to the remainder of the implant.