SYSTEMS AND METHODS FOR PERFORMING SURGICAL PROCEDURES AND ASSESSMENTS
The present invention involves systems and related methods for performing surgical procedures and assessments, including the use of neurophysiology-based monitoring to: (a) determine nerve proximity and nerve direction to surgical instruments employed in accessing a surgical target site; (b) assess the pathology (health or status) of a nerve or nerve root before, during, or after a surgical procedure; and/or (c) assess pedicle integrity before, during or after pedicle screw placement, all in an automated, easy to use, and easy to interpret fashion so as to provide a surgeon-driven system.
1 . A method for performing surgical procedures and assessments, the method comprising:
providing an electrical stimulation signal to a surgical accessory comprising at least one stimulation electrode;
measuring a response of nerves depolarized by the electrical stimulation signal;
determining a stimulation threshold of the nerves by adjusting the electrical stimulation signal according to variable increments; and
providing for display a range of at least two preselected ranges that the stimulation threshold lies to indicate at least one of nerve proximity and pedicle integrity.
2 . The method of claim 1 , wherein the response of the depolarized nerves is measured by monitoring electromyography waveforms of myotomes associated with the depolarized nerves.
3 . The method of claim 1 , further comprising:
establishing an operative corridor to a surgical target site.
4 . The method of claim 3 , wherein establishing the operative corridor comprises advancing a series of sequential dilator cannulae, wherein each of the series of sequential dilator cannulae comprises at least one stimulation electrode near a distal end.
5 . The method of claim 3 , wherein the surgical target site is a spinal target site.
6 . The method of claim 5 , wherein the operative corridor is established via a lateral, trans-psoas approach.
7 . The method of claim 1 , wherein the at least two pre-selected threshold ranges comprise a safe range and an unsafe range.
8 . The method of claim 7 , wherein the at least two preselected threshold ranges comprises a cautionary range in-between the safe range and the unsafe range.
9 . The method of claim 1 , the method further comprising:
providing for display at least one of alpha-numeric and graphic indicia related to at least one of nerve proximity and pedicle integrity.
10 . The method of claim 1 , wherein the surgical accessory comprises a pedicle testing device that includes a handle and a pedicle probe.
11 . A method for performing surgical procedures and assessments, the method comprising:
providing an electrical stimulation signal to a surgical accessory comprising at least one stimulation electrode;
measuring a response of nerves depolarized by the electrical stimulation signal;
determining a stimulation threshold of the nerves by (i) doubling an amplitude of successive electrical stimulation signals until a corresponding nerve so response measures at least a preselected intensity level and (ii) decreasing an amplitude of subsequent electrical stimulation signals until a corresponding nerve response measures below the preselected intensity level; and
providing for display a range of at least two preselected ranges that the stimulation threshold lies to indicate at least one of nerve proximity and pedicle integrity.
12 . The method of claim 11 , wherein the response of the depolarized nerves is measured by monitoring electromyography waveforms of myotomes associated with the depolarized nerves.
13 . The method of claim 11 , further comprising:
establishing an operative corridor to a surgical target site.
14 . The method of claim 14 , wherein establishing the operative corridor comprises advancing a series of sequential dilator cannulae, wherein each of the series of sequential dilator cannulae comprises at least one stimulation electrode near a distal end.
15 . The method of claim 13 , wherein the surgical target site is a spinal target site.
16 . The method of claim 13 , wherein the operative corridor is established via a lateral, trans-psoas approach.
17 . The method of claim 11 , wherein the at least two pre-selected threshold ranges comprise a safe range and an unsafe range.
18 . The method of claim 17 , wherein the at least two preselected threshold ranges comprises a cautionary range in-between the safe range and the unsafe range.
19 . The method of claim 11 , further comprising:
providing for display at least one of alpha-numeric and graphic indicia related to at least one of nerve proximity and pedicle integrity.
20 . The method of claim 11 , wherein the surgical accessory comprises a pedicle testing device that includes a handle and a pedicle probe.