Systems and methods for performing surgical procedures and assessments

Abstract

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 . (canceled) 
     
     
         2 . A method of inserting a spinal implant through a trans-psoas operative corridor to an intervertebral disc of a spine in a patient, the patient having an anterior aspect, a posterior aspect and two lateral aspects, the method comprising:
 using a control unit operable to provide a stimulation signal and including a graphical user interface to receive user input and to display neuromuscular response information in response to signals from a plurality of sensors mounted on the patient;   inserting an elongate stimulation instrument into the patient from one lateral aspect of the two lateral aspects of the patient toward a lateral aspect of the spine, and advancing the elongate stimulation instrument along a lateral, trans-psoas path through bodily tissue toward the lateral aspect of the spine;   using the elongate stimulation instrument to deliver the stimulation signal proximate to a distal end of the elongate stimulation instrument while the elongate stimulation instrument is inserted into the lateral, trans-psoas path toward the spine;   monitoring the neuromuscular response information displayed by the control unit in response to delivery of the stimulation signal while the elongate stimulation instrument is inserted into the lateral, trans-psoas path toward the spine;   advancing the elongate stimulation instrument, based on the using the elongate stimulation instrument and monitoring, along the lateral, trans-psoas path and through a region of a psoas muscle containing lumbosacral plexus nerves while avoiding direct contact with the lumbosacral plexus nerves;   sequentially advancing, after advancing the elongate stimulation instrument along the lateral, trans-psoas path, a first sequential dilator and a second sequential dilator along the lateral, trans-psoas path toward the spine, the first sequential dilator having a diameter smaller than that of the second sequential dilator;   advancing a working corridor instrument over the second sequential dilator in the lateral, trans-psoas path toward the spine;   establishing the trans-psoas operative corridor to the intervertebral disc of the spine using the working corridor instrument, the trans-psoas operative corridor extending along the lateral, trans-psoas path; and   delivering a spinal fusion implant through the trans-psoas operative corridor toward the spine.   
     
     
         3 . The method of  claim 2 , wherein the plurality of sensors comprises a plurality of EMG electrodes. 
     
     
         4 . The method of  claim 2 , wherein the lateral, trans-psoas path extends along a trajectory which exits a second lateral aspect of the two lateral aspects of the patient. 
     
     
         5 . The method of  claim 2 , wherein using the control unit comprises using a neurophysiology monitoring unit configured to: measure the response of the lumbosacral plexus nerves innervated by the stimulation signal, determine a relationship between the elongate stimulation instrument and a lumbosacral plexus nerve based on the measured response, and communicate the relationship via a display device. 
     
     
         6 . The method of  claim 5 , wherein the stimulation signal delivered by the elongate stimulation instrument comprises stimulation current pulses, and the neuromuscular response information displayed by the control unit comprises a numeric stimulation threshold current level. 
     
     
         7 . The method of  claim 6 , wherein the numeric stimulation threshold current level displayed by the control unit indicates an amplitude of the stimulation current pulses that evokes an EMG response having an amplitude value greater than a predetermined voltage value. 
     
     
         8 . The method of  claim 6 , wherein the stimulation current pulses of the signal delivered by the elongate stimulation instrument comprises rectangular monophasic current pulses output from the elongate stimulation instrument while the elongate stimulation instrument is inserted into the lateral, trans-psoas path. 
     
     
         9 . The method of  claim 2 , wherein the lateral, trans-psoas path is oriented at 90 degrees rotational offset relative to a midline of the patient. 
     
     
         10 . The method of  claim 2 , wherein the lateral, trans-psoas path passes through a lateral portion of the psoas muscle. 
     
     
         11 . The method of  claim 2 , wherein the elongate stimulation instrument is equipped with a single stimulation electrode. 
     
     
         12 . The method of  claim 11 , wherein the single stimulation electrode of the elongate stimulation dilator is oriented at an angle within a range of 5 degrees to 85 degrees relative to a longitudinal axis of the elongate stimulation instrument. 
     
     
         13 . The method of  claim 2 , further comprising rotating the elongate stimulation instrument while advancing the elongate stimulation instrument along the lateral, trans-psoas path and performing at least one of (1) delivering the stimulation signal while the elongate stimulation instrument is in a rotated position, and (2) monitoring the neuromuscular response information while rotating the elongate stimulation instrument. 
     
     
         14 . The method of  claim 2 , further comprising advancing the elongate stimulation instrument along the lateral, trans-psoas path to negotiate around the lumbosacral plexus nerves in the psoas muscle of the patient based on monitoring the neuromuscular response information. 
     
     
         15 . The method of  claim 2 , further comprising detecting proximity, in response to delivery of the stimulation signal, of a lumbosacral plexus nerve in the psoas muscle of the patient while advancing of the elongate stimulation instrument along the lateral, trans-psoas path. 
     
     
         16 . The method of  claim 2 , further comprising determining direction of a lumbosacral plexus nerve in the psoas muscle of the patient while advancing of the elongate stimulation instrument along the lateral, trans-psoas path, in response to delivery of the stimulation signal. 
     
     
         17 . A method of inserting a spinal implant through a trans-psoas operative corridor to an intervertebral disc of a spine in a patient, the patient having an anterior aspect, a posterior aspect and two lateral aspects, the method comprising:
 inserting an elongate stimulation instrument into the patient from one lateral aspect of the two lateral aspects of the patient toward a lateral aspect of the spine, and advancing the elongate stimulation instrument along a lateral, trans-psoas path through bodily tissue toward the lateral aspect of the spine;   delivering, using the elongate stimulation instrument, a stimulation signal proximate to a distal end of the elongate stimulation instrument while the elongate stimulation instrument is inserted into the lateral, trans-psoas path toward the spine;   monitoring the neuromuscular response information, in response to signals from a plurality of sensors mounted proximate to selected leg muscles of the patient, subsequent to delivery of the stimulation signal while the elongate stimulation instrument is inserted into the lateral, trans-psoas path toward the spine;   advancing the elongate stimulation instrument, based on the monitoring, along the lateral, trans-psoas path and through a region of a psoas muscle containing nerves without impairing the nerves;   establishing the trans-psoas operative corridor to the intervertebral disc of the spine using a working corridor instrument; and   delivering a spinal fusion implant through the trans-psoas operative corridor toward the spine.   
     
     
         18 . The method of  claim 17 , wherein the plurality of sensors comprises a plurality of EMG electrodes. 
     
     
         19 . The method of  claim 17 , wherein the lateral, trans-psoas path extends along a trajectory which exits a second lateral aspect of the two lateral aspects of the patient. 
     
     
         20 . The method of  claim 17 , further comprising using a neurophysiology monitoring unit configured to: measure the response of the nerves innervated by the stimulation signal, determine a relationship between the elongate stimulation instrument and a nerve based on the measured response, and communicate the relationship via a display device. 
     
     
         21 . The method of  claim 20 , wherein the stimulation signal delivered by the elongate stimulation instrument comprises stimulation current pulses, and the neuromuscular response information displayed by the control unit comprises a numeric stimulation threshold current level. 
     
     
         22 . The method of  claim 20 , wherein the numeric stimulation threshold current level displayed by the control unit indicates an amplitude of the stimulation current pulses that evokes an EMG response having an amplitude value greater than a predetermined voltage value. 
     
     
         23 . The method of  claim 20 , wherein the stimulation current pulses of the signal delivered by the elongate stimulation instrument comprises rectangular monophasic current pulses output from the elongate stimulation instrument while the elongate stimulation instrument are inserted into the lateral, trans-psoas path. 
     
     
         24 . The method of  claim 17 , wherein the lateral, trans-psoas path is oriented at 90 degrees rotational offset relative to a midline of the patient. 
     
     
         25 . The method of  claim 17 , wherein the lateral, trans-psoas path passes through a lateral portion of the psoas muscle. 
     
     
         26 . The method of  claim 17 , wherein the elongate stimulation instrument is equipped with a single stimulation electrode. 
     
     
         27 . The method of  claim 26 , wherein the single stimulation electrode of the elongate stimulation dilator is oriented at an angle within a range of 5 degrees to 85 degrees relative to a longitudinal axis of the elongate stimulation instrument. 
     
     
         28 . The method of  claim 17 , further comprising rotating the elongate stimulation instrument while advancing the elongate stimulation instrument along the lateral, trans-psoas path and performing at least one of (1) delivering the stimulation signal while the elongate stimulation instrument is in a rotated position, and (2) monitoring the neuromuscular response information while rotating the elongate stimulation instrument. 
     
     
         29 . The method of  claim 17 , further comprising advancing the elongate stimulation instrument along the lateral, trans-psoas path to negotiate around the nerves in the psoas muscle of the patient based on monitoring the neuromuscular response information. 
     
     
         30 . The method of  claim 17 , further comprising detecting proximity, in response to delivering the stimulation signal, of a nerve in the psoas muscle of the patient while advancing of the elongate stimulation instrument along the lateral, trans-psoas path. 
     
     
         31 . The method of  claim 17 , further comprising determining direction of a nerve in the psoas muscle of the patient while advancing of the elongate stimulation instrument along the lateral, trans-psoas path, in response to delivering the stimulation signal.