Method and apparatus for monitoring disc pressure during heat treatment of an intervertebral disc
A probe system and method for treating an intervertebral disc of a patient are disclosed. A probe has a cannula having an open end defined at a distal end and adapted to couple to a power source. A stylet fits into the cannula so that a distal end of the stylet occludes the open end at the distal end of the cannula. The probe system also includes a pressure monitoring apparatus coupled to the stylet, with the stylet including a pressure sensor in proximity to the distal end of the stylet. The pressure sensor communicates with the pressure monitoring apparatus to measure the pressure of the intervertebral disc. The power source delivers power to the distal end of the cannula, causing heating of the disc when the distal end of the cannula is disposed within the disc, thereby relieving patient pain associated with the disc.
1. A method of treating back and neck pain of a patient by radiofrequency heating of an intervertebral disc, comprising the steps of:
providing a radiofrequency electrode including proximal and distal ends and having a keyed slot defined therein, the keyed slot including at least two openings separated from each other by a distance along the length of the radiofrequency electrode, the radiofrequency electrode comprising:
a cannula having a proximal end and a distal end and having an open end defined at the distal end thereof, the cannula including a substantially insulated shaft with an uninsulated conductive radiofrequency tip at the distal end thereof, the radiofrequency tip adapted for insertion between intervertebral discs of a patient, the cannula adapted to couple to a power source through a radiofrequency connection attached to the proximal end thereof;
a stylet having a proximal end and a distal end, the stylet fitting into the cannula so that the distal end of the stylet occludes the open end at the distal end of the cannula, the stylet having a key portion configured to operably engage at least one of the openings of the keyed slot, the stylet including a pressure sensor probe proximate the distal end of the stylet, the pressure sensor probe adapted to monitor pressure in the intervertebral disc as the radiofrequency electrode heats the intervertebral disc;
and
an electrical connection between the radiofrequency connection and the radiofrequency tip, the electrical connection providing electrical communication between the radiofrequency connection and the radiofrequency tip;
inserting the radiofrequency electrode into the body of a patient;
positioning the key portion within a first of the at least two openings of the keyed slot of the radiofrequency electrode;
connecting an external radiofrequency generator to the radiofrequency connection so as to apply a radiofrequency voltage generated by the radiofrequency generator to the radiofrequency tip via the electrical connection;
increasing the radiofrequency voltage to cause current to flow from the radiofrequency tip into the intervertebral disc when the radiofrequency tip is placed therein to cause changes in the intervertebral disc material and nearby neurological structures;
monitoring the pressure in the intervertebral disc using the pressure sensor probe;
and
re-positioning the key portion within a second of the at least two openings of the keyed slot of the radiofrequency electrode.
2. A method according to claim 1 , wherein immediately following the step of increasing the radiofrequency voltage to cause current to flow from the radiofrequency tip into the intervertebral disc when the radiofrequency tip is placed within the intervertebral disc, the method further comprises the step of turning off the radiofrequency voltage.
3. A method according to claim 2 , wherein following the step of turning off the radio frequency voltage, the method further comprises the steps of waiting for a period of approximately one minute and measuring the pressure sensed by the pressure sensor probe.
4. A method according to claim 3 , wherein, if it is determined that further treatment is necessary based upon the measured pressure, the method further comprises the steps of:
re-connecting the external radiofrequency generator to the radiofrequency connection so as to apply a radiofrequency voltage generated by the radiofrequency generator to the radiofrequency tip via the electrical connection; and
increasing the radiofrequency voltage to cause current to flow from the radiofrequency tip into the intervertebral disc when the radiofrequency tip is placed within the intervertebral disc.
5. A method according to claim 1 , wherein the pressure sensor probe includes an aperture defined therein and a pressure sensor that is at least partially exposed through the aperture to thereby sense pressure in the disc.
6. A probe electrode comprising:
a hub, the hub having a keyed slot defined therein that extends along a portion of the length of the hub;
a cannula having a proximal end and a distal end and having an open end defined at the distal end thereof, the cannula having a radiofrequency tip at the distal end thereof, the cannula adapted to couple to a power source;
the hub and the cannula defining a needle; and
a stylet having a proximal end and a distal end, the stylet fitting into the cannula so that the distal end of the stylet occludes the open end at the distal end of the cannula, the stylet having a key portion,
the stylet including a pressure sensor proximate the distal end of the stylet, the pressure sensor adapted to communicate with a pressure monitoring apparatus so as to measure the pressure of the intervertebral disc,
wherein the keyed slot of the hub includes at least two openings that are separated from each other by a distance along the length of the hub, the at least two openings configured to operably engage the key portion of the stylet.
7. A probe electrode according to claim 6 , wherein the stylet includes an electrical connector adapted to connect the radiofrequency tip to a power generator for generating heat at the distal end of the cannula.
8. A probe electrode according to claim 6 , wherein the cannula has a lumen defined therein and the stylet includes a shaft configured for variable insertion within the lumen through the proximal end of the cannula such that the position of the pressure sensor can be varied within the lumen of the cannula.
9. A probe electrode according to claim 6 , wherein the pressure sensor monitors pressure at a position in the intervertebral disc.
10. A probe electrode according to claim 8 , wherein the pressure sensor monitors pressure at a plurality of positions in the intervertebral disc and the stylet is selectively movable to an extended position equal to the distance along the hub wherein the key portion engages the keyed slot via one of the at least two openings.
11. A probe electrode according to claim 6 , wherein the stylet includes an aperture defined therein and the pressure sensor is at least partially exposed through the aperture to thereby sense pressure in the disc.