Monitoring characteristics of an intervertebral disc and/or prosthesis material

Abstract

A vertebral disc prosthesis, a method of implanting a prosthesis and a deployment device is provided. The prosthesis may be implanted into the interior region of the vertebral disc so as to displace existing vertebral tissue, such as NP. The size or amount of the prosthesis inserted into the interior region of the vertebral disc may be a characteristic of the disc or the prosthesis. For example, the amount or size of prosthesis inserted into the disc may be dependent upon restoring the functionality of the disc (e.g., the ability of the disc to transfer nutrients or otherwise survive, the ability of the disc to carry the required loads and absorb stress or the reduction of pain). The method may include monitoring at least one of: a) one or more characteristics of the vertebral disc, and b) one or more characteristics of the prosthesis.

1 . A method or implanting a prosthesis material into an interior region of a vertebral disc, the vertebral disc having first and second endplates, the method comprising:
 locating an access site on the disc;   inserting, through an opening of the disc at the access site, the prosthesis material into the interior region of the vertebral disc without removing a substantial amount of nucleus pulposus;   spacing the prosthesis material from the endplates of the vertebral disc such that the nucleus pulposus substantially surrounds the prosthesis material; and   monitoring at least one of: a) one or more characteristics of the vertebral disc, and b) one or more characteristics of the prosthesis material.   
     
     
         2 . The method according to  claim 1 , wherein locating an access site comprises forming an opening in the annulus fibrosis of the vertebral disc. 
     
     
         3 . The method according to  claim 1 , wherein locating an access site comprises locating a defect in the annulus fibrosis of the vertebral disc. 
     
     
         4 . The method according to  claim 1 , wherein monitoring one or more characteristics of the vertebral disc comprises monitoring a disc height of the vertebral disc. 
     
     
         5 . The method according to  claim 1 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired increased disc height is achieved. 
     
     
         6 . The method according to  claim 5 , wherein inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired increased disc height is achieved comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a height ranging between approximately 1 mm and approximately 10 mm is achieved. 
     
     
         7 . The method according to  claim 5 , wherein inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired increased disc height is achieved comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a height ranging between approximately 0.1 mm and approximately 3 mm is achieved. 
     
     
         8 . The method according to  claim 5 , wherein inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired increased disc height is achieved comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a height ranging between approximately 3 mm and approximately 6 mm is achieved. 
     
     
         9 . The method according to  claim 5 , wherein inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired disc height is achieved comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a height ranging between approximately 6 mm and approximately 9 mm is achieved. 
     
     
         10 . The method according to  claim 1 , wherein monitoring one or more characteristics of the prosthesis material comprises monitoring a volume of prosthesis material inserted into the interior region of the vertebral disc. 
     
     
         11 . The method according to  claim 10 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting approximately 0.1 ml to approximately 6 ml of the prosthesis material into the interior region of the vertebral disc. 
     
     
         12 . The method according to  claim 1 , wherein monitoring one or more characteristics of the vertebral disc comprises monitoring a disc pressure of the vertebral disc. 
     
     
         13 . The method according to  claim 12 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired disc pressure is achieved. 
     
     
         14 . The method according to  claim 13 , wherein inserting an amount of prosthesis material into the interior region of the vertebral disc until a desired disc pressure is achieved comprises inserting an amount of prosthesis material into the interior region of the vertebral disc until a disc pressure ranging between approximately 1 atmospheres and 5 atmospheres is achieved. 
     
     
         15 . The method according to  claim 1 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting hydrogel material into the interior region of the vertebral disc. 
     
     
         16 . The method according to  claim 1 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting an isotropic mass of material into the interior region of the vertebral disc. 
     
     
         17 . The method according to  claim 1 , further comprising shaping the prosthesis material so as to resist extrusion from the interior region of the vertebral disc. 
     
     
         18 . The method according to  claim 1 , further comprising positioning the prosthesis material so as to alter an axis of rotation of the spine. 
     
     
         19 . The method according to  claim 1 , further comprising forming the prosthesis material with a therapeutic amount of a desired substance. 
     
     
         20 . The method according to  claim 1 , wherein inserting the prosthesis material into the interior region of the vertebral disc comprises inserting a prosthesis material having compressive strength that is less than 4 MN/m 2 . 
     
     
         21 . The method according to  claim 1 , further comprising locating the prosthesis material within the interior region of the vertebral disc and adjacent the annulus fibrosis. 
     
     
         22 . The method according to  claim 1 , wherein the step of monitoring at least one of: a) one or more characteristics of the vertebral disc, and b) one or more characteristics of the prosthesis material comprises:
 monitoring at least one said characteristic of the disc and at least one said characteristic of the prosthesis material.   
     
     
         23 . The method according to  claim 1 , wherein the step of monitoring a disc characteristic comprises:
 monitoring a characteristic selected from the group consisting of one or more of the following: disc height, disc pressure, and disc volume.   
     
     
         24 . The method according to  claim 1 , wherein the step of monitoring occurs during insertion of said prosthesis material. 
     
     
         25 . The method according to  claim 1 , wherein the step of monitoring at least one of: a) one or more characteristics of the vertebral disc, and b) one or more characteristics of the prosthesis material comprises:
 monitoring the height of the disc at one or more of the following times: during the implantation procedure, prior to the implantation procedure or after the implantation procedure.   
     
     
         26 . The method according to  claim 25 , further comprising
 obtaining comparative data obtained from monitoring the height of the disc at two or more of the following times: during the implantation procedure, prior to the implantation procedure or after the implantation procedure; and   using said data to evaluate disc height.