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 initial dilator 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 initial dilator along a trans-psoas path through bodily tissue toward the lateral aspect of the spine;   using an elongate stimulation instrument disposed within an inner lumen of the initial dilator to deliver the stimulation signal proximate to a distal end of the initial dilator while the initial dilator is inserted into the 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 initial dilator is inserted into the trans-psoas path toward the spine;   sequentially advancing a first sequential dilator and a second sequential dilator along the 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 along the trans-psoas path toward the spine;   establishing the trans-psoas operative corridor to the intervertebral disc of the spine using the working corridor instrument; 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 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 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. 
     
     
         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 initial dilator and the elongate stimulation instrument are inserted into the trans-psoas path. 
     
     
         9 . The method of  claim 2 , wherein the 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 trans-psoas path passes through a lateral portion of a psoas muscle. 
     
     
         11 . The method of  claim 2 , wherein both the elongate stimulation instrument and the initial dilator are each 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, and the single stimulation electrode of the initial dilator is oriented at an angle within a range of 5 degrees to 85 degrees relative to a longitudinal axis of the initial dilator. 
     
     
         13 . The method of  claim 2 , further comprising rotating the initial dilator while advancing the initial dilator along the trans-psoas path and performing at least one of (1) delivering the stimulation signal while the initial dilator is in a rotated position, and (2) monitoring the neuromuscular response information while rotating the initial dilator. 
     
     
         14 . The method of  claim 2 , further comprising advancing the elongate stimulation instrument along the trans-psoas path to negotiate around nerves in a 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 nerve in a psoas muscle of the patient while advancing of the elongate stimulation instrument along the trans-psoas path. 
     
     
         16 . The method of  claim 2 , further comprising determining direction of a nerve in a psoas muscle of the patient while advancing of the elongate stimulation instrument along the 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, 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 initial dilator into the patient from an anatomically lateral aspect of the patient toward a lateral aspect of the spine, and advancing the initial dilator along an anatomically lateral trans-psoas path through bodily tissue toward the lateral aspect of the spine;   using an elongate stimulation instrument disposed within an inner lumen of the initial dilator to deliver the stimulation signal proximate to a distal end of the initial dilator while the initial dilator is inserted into the anatomically 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 initial dilator is inserted into the anatomically lateral trans-psoas path toward the spine;   sequentially advancing a first sequential dilator and a second sequential dilator along the anatomically 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 along the anatomically 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; 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 anatomically 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 , wherein using the control unit comprises using a neurophysiology monitoring unit configured to: measure the response of 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 initial dilator and the elongate stimulation instrument are inserted into the anatomically lateral trans-psoas path. 
     
     
         24 . The method of  claim 17 , wherein the anatomically 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 anatomically lateral trans-psoas path passes through a lateral portion of a psoas muscle. 
     
     
         26 . The method of  claim 17 , wherein both the elongate stimulation instrument and the initial dilator are each 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, and the single stimulation electrode of the initial dilator is oriented at an angle within a range of 5 degrees to 85 degrees relative to a longitudinal axis of the initial dilator. 
     
     
         28 . The method of  claim 17 , further comprising rotating the initial dilator while advancing the initial dilator along the anatomically lateral trans-psoas path and performing at least one of (1) delivering the stimulation signal while the initial dilator is in a rotated position, and (2) monitoring the neuromuscular response information while rotating the initial dilator. 
     
     
         29 . The method of  claim 17 , further comprising advancing the elongate stimulation instrument along the anatomically lateral trans-psoas path to negotiate around nerves in a 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 delivery of the stimulation signal, of a nerve in a psoas muscle of the patient while advancing of the elongate stimulation instrument along the anatomically lateral trans-psoas path. 
     
     
         31 . The method of  claim 17 , further comprising determining direction of a nerve in a psoas muscle of the patient while advancing of the elongate stimulation instrument along the anatomically lateral trans-psoas path, in response to delivery of the stimulation signal.