Track One. Spine Surgery.

Transcription

1 Track One Spine Surgery 18

2 Spine Instrumentation: Methodology and Approaches Ricardo B. V. Fontes, MD, PhD 19

3 Spine instrumenta-on: methodology and approaches Ricardo Fontes, MD, PhD Department of Neurosurgery, RUMC 2016 ASNM Annual Mee-ng, Chicago IL May 12-15, 2016 Disclosures Consultant work: Stryker 2 20

4 Spine surgery why? Allow normal function of the spinal column Nervous system Musculoskeletal system Neurological function Adequate functioning of the spinal cord and nerves Static / dynamic compression Decompression Trauma Infection Neoplasms Degenerative Musculoskeletal function 3 Spine surgery why? Allow normal function of the spinal column Nervous system Musculoskeletal system Neurological function Adequate functioning of the spinal cord and nerves Static / dynamic compression Decompression Trauma Infection Neoplasms Degenerative Musculoskeletal function 4 21

5 Spine surgery why? Allow normal function of the spinal column Nervous system Musculoskeletal system Neurological function Musculoskeletal function Alignment Head Cervical Thoracic Lumbopelvic Stability Durability 5 Spinal stability Clinical definition Ability to withstand physiologic loads and allow normal function Neurological deficits Pain Alignment Radiological definition Instability Spectrum Not a point Cause matters 6 22

6 Spinal stability Clinical definition Ability to withstand physiologic loads and allow normal function Neurological deficits Pain Alignment Radiological definition Instability Spectrum Not a point Cause matters 7 Spinal stability Clinical definition Ability to withstand physiologic loads and allow normal function Neurological deficits Pain Alignment Radiological definition Instability Spectrum Not a point Cause matters 8 23

7 Spinal stability Cervical spine: Horizontal gaze Allows for normal neurological function Myelopathy Radiculopathy Allows normal function of other cervical structures Swallowing Respiration Vascular With minimal energy expenditure 9 Spinal stability Cervical spine: Horizontal gaze Allows for normal neurological function Myelopathy Radiculopathy Allows normal function of other cervical structures Swallowing Respiration Vascular With minimal energy expenditure 10 24

8 Spinal stability Lumbar spine: Erect posture Allows for normal neurological function Radiculopathy Allows normal function of other thoracoabdminal structures Less common compromise With minimal energy expenditure 11 Spinal instrumenta-on General concepts Important part of the operation Important adjuvant tool for the surgeon Never the objective of operation Assists surgeon to achieve the objectives of surgery Decompression Stabilization Alignment If the same result can be achieved without instrumentation, do not use it 12 25

9 Spinal instrumenta-on General concepts Important part of the operation Important adjuvant tool for the surgeon Never the objective of operation Assists surgeon to achieve the objectives of surgery Decompression Stabilization Alignment If the same result can be achieved without instrumentation, do not use it 13 Spinal instrumenta-on General concepts Important part of the operation Important adjuvant tool for the surgeon Never the objective of operation Assists surgeon to achieve the objectives of surgery Decompression Stabilization Alignment If the same result can be achieved without instrumentation, do not use it 14 26

10 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Little consensus on how to perform it Training Experience Frequency 15 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique 16 27

11 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique 17 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique 18 28

12 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique 19 Spinal instrumenta-on Inserting spinal instrumentation Surgeons rely on multiple cues Anatomy Imaging Fluoroscopy (2D and 3D) Tomography Navigation Neuromonitoring Robotics Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique 20 29

13 Spinal instrumenta-on Inserting spinal instrumentation Older / simpler implants 1- or 2-column fixation Simpler / less powerful Anatomy Engineering Surgical technique Not in close relationship to neural structures Small corrections Structurally stable pathology 21 Spinal instrumenta-on More complex instrumentation / pathology More decompression / correction More instability More invasive instrumentation Reliance on more cues Imaging Neuromonitoring Importance of each cue depends on pathology and procedure Also, surgeon preference Little consensus 22 30

14 Spinal instrumenta-on Examples: Cervical Anterior Posterior 23 Spinal instrumenta-on Examples: Cervical Anterior Posterior 24 31

15 Spinal instrumenta-on Examples: Cervical Anterior Posterior 25 Spinal instrumenta-on Examples: Cervical Anterior Posterior 26 32

16 Spinal instrumenta-on Examples: Cervical Anterior Posterior 27 Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation - more recent Smaller spinal canal Pathology also tends to result in more cord compression Adolescent scoliosis 28 33

17 Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation - more recent Smaller spinal canal Pathology also tends to result in more cord compression Adolescent scoliosis 30 34

18 Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation - more recent Smaller spinal canal Pathology also tends to result in more cord compression Adolescent scoliosis 31 Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation - more recent Smaller spinal canal Pathology also tends to result in more cord compression Adolescent scoliosis 32 35

19 Spinal instrumenta-on Thoracic instrumentation Anterior Posterior Pedicle fixation - more recent Smaller spinal canal Pathology also tends to result in more cord compression Adolescent scoliosis 33 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 34 36

20 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 35 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 36 37

21 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 37 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 38 38

22 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 39 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 40 39

23 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 41 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 42 40

24 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral Guerin et al., Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral Guerin et al.,

25 Spinal instrumenta-on Lumbar instrumentation Anterior Posterior Pedicle fixation most common Cord normally ending above L2-3 Adult deformity (kyphoscoliosis) Lateral 45 Conclusions Part of the operation Keep in mind 3 objectives Decompression Stabilization Alignment Rely on cues Rely on team Excellent instrumentation placement Excellent correction of alignment Excellent results Thank you! Ricardo Fontes ricardo_fontes@rush.edu (224)

26 Legal Disclaimer THIS PRESENTATION IS THE PROPERTY OF FONTES AND CANNOT BE UTILIZED IN WHOLE OR IN PART FOR COMMERCIAL PURPOSES WITHOUT PRIOR AUTHORIZATION EXCEPT AS PROVIDED HEREIN. AUTHORIZATION AUTOMATICALLY GRANTED FOR PERSONAL, EDUCATIONAL AND OTHER NON- COMMERCIAL PURPOSES. FONTES, FOR HIMSELF AND ANY THIRD PARTY PROVIDING MATERIALS, SERVICES, OR CONTENT TO THIS PRESENTATION, MAKE NO REPRESENTATIONS OR WARRANTIES IN CONNECTION WITH THE PRESENTATION INCLUDING BUT NOT LIMITED TO THE QUALITY, SUITABILITY, TRUTH, ACCURACY, OR COMPLETENESS OF ANY MATERIAL, INFORMATION, PRODUCT, OR SERVICE CONTAINED IN THE PRESENTATION. ALL CONDITIONS, REPRESENTATIONS, AND WARRANTIES, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON- INFRINGEMENT OF THIRD PARTY RIGHTS, ARE HEREBY DISCLAIMED. FONTES WILL NOT BE LIABLE TO YOU OR ANY THIRD PARTY FOR ANY DAMAGES OF ANY KIND, INCLUDING BUT NOT LIMITED TO, DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES, ARISING FROM OR CONNECTED WITH THE PRESENTATION, INCLUDING BUT NOT LIMITED TO, YOUR USE OF THIS PRESENTATION OR YOUR INABILITY TO USE THE PRESENTATION, EVEN IF FONTES HAS PREVIOUSLY BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES

27 Spinal Tumor Surgery John O Toole, MD, MS 44

28 Neuromonitoring During Spine Instrumentation Procedures Faisal R. Jahangiri, MD, CNIM, DABNM, FASNM 45

29 ASNM 2016 The Evidence of Methodology for Neuromonitoring NEUROMONITORING DURING SPINE INSTRUMENTATION SURGERIES FAISAL R. JAHANGIRI MD, CNIM, D.ABNM, FASNM Consultant Physician, Clinical Neurophysiology Division of Neurology, Department of Medicine Ministry Of National Guard Health Affairs, King AbdulAziz Medical City, Riyadh, Saudi Arabia Disclosure No Disclosure 46

30 Objectives The objectives of this presentation is: 1. To understand the anatomy for the spine and related structures. 2. To understand the modalities that can be used during spinal instrumentation surgeries. 3. To understand the various spinal instrumentation procedures. 4. To understand the anesthetic requirements. 5. To understand the interpretation of the changes in the data. Introduction Multimodality Monitoring for Spinal Instrumentation Surgeries: Somatosensory Evoked Potentials (SSEP) Upper SEP Lower SEP Motor Evoked Potentials (TCeMEP) CMAP D-waves Electromyography (EMG) T-EMG Pedicle Screw Stimulation SI Screw Stimulation 47

31 Modalities Somatosensory Evoked Potentials (SSEP) Somatosensory Evoked Potentials (SSEP) Advantages of SSEP: Intra-operatively sensory ascending pathways can be monitored continuously by somatosensory evoked potentials (SSEP) without interrupting the surgical procedure. SSEP are very effective and sensitive in monitoring the dorsal-medial column pathways. Intraoperative SSEP monitoring gives a continuous feedback to the surgeon about the functional integrity of the dorsal column pathways. This decreases the risk of any mechanical and ischemia changes to the dorsal column pathways, brainstem, brain, and peripheral nerves. The main blood supply to the sensory pathways is from two posterior spinal arteries supplying about posterior 2/3 of the spinal cord, whereas anterior 1/3 of the spinal cord with motor pathways is supplied by anterior spinal artery. 48

32 Somatosensory Evoked Potentials (SSEP) Disadvantages of SSEP: In order to perform SSEP on patients under anesthesia, an averaging of signals is needed for each recorded trace to cancel out unwanted signals, such as noise, EEG, EMG, etc. It requires approximately 2-3 minutes of time for each trace. The SSEP monitoring is also limited in assessing the spinal cord function because of its limitation to monitoring only sensory pathways, and being unable to detect changes in descending motor pathways. There have been few reported cases in literature where SSEP responses were not changed but TCeMEP responses were lost. Anesthesia, blood pressure, ischemia, and temperature, are a few of the peri-surgical factors that affect SSEP responses. SSEP should be monitored for at least 30 minutes more after the last spinal correction. Sometimes it may take minutes to see the changes in SSEP. It should be noted that a case of hyperthermia, as well as an increase in length of the limbs, will result in delayed responses. Somatosensory Evoked Potentials (SSEP) Anesthesia: The effect of anesthetic agents is significant on SSEP responses by increasing the latency and decreasing the amplitude of the responses. The effects of anesthesia is dose dependent, are more prominent on cortical SSEP responses, less on subcortical, and the least on peripheral responses. These effects vary from one patient to another depending on various pre-operative factors, such as patient age, history of alcohol or abuse, neurological abnormalities, vascular deficiencies, history of stroke, diabetes mellitus, etc. The anesthetic effects are always present bilaterally. All neural generators on the pathways are affected, starting from the later cortical peaks moving towards earlier cortical peaks. The exceptions to this rule are two drugs, etomidate and ketamine, which cause an increase in amplitude of cortical SSEP responses 49

33 Somatosensory Evoked Potentials (SSEP) Alarm Criteria: If there is more than a 10% increase in latency or 50% or more decrease in cortical amplitude it should be considered as alarm criteria and the surgeon should be informed immediately. There is no published data confirming this criterion, but it is being used for many decades now. There are a number of factors considered before alarming the surgeon including: variability of the responses, effect of anesthesia, any pre-existing neurologic conditions, rate of change in signals, related surgical events. Somatosensory Evoked Potentials (SSEP) Median Nerve Setup: Ground: Palmar surface of the forearm Stimulation intensity: 25 ma Stimulation rater (rep rate) = 2-8/second Band-pass filters: Low frequency filter: Cortical: 1-30 Hz Spinal: Hz Peripheral: Hz High frequency filter: Cortical: Hz Spinal: Hz Peripheral: Hz Sweep: 40 milliseconds (4 millisec/division) Number of averages:

34 Somatosensory Evoked Potentials (SSEP) Median Nerve Setup: Recording channels: Stimulation setup: CPc-CPi CPi-FPz CV5-FPz EPi-EPc Cathode: should be placed between the tendons of the Palmaris Longus and Flexor Carpi Radialis muscles, 2 cm proximal to the crease of the wrist. Anode: should be placed 2-3 cm distal to the cathode on the palmar surface Somatosensory Evoked Potentials (SSEP) Obligate Waves for Median and Ulnar nerve SSEPs: EP: Erb s point response: a near-field, propagated peripheral nerve response N13: A near-field stationary response; cervical response from dorsal column P14: A far-field subcortical response from the caudal medial lemniscus, CPi-Epc N18: A far-field subcortical response from the brainstem / thalamus, CPi-Epc N20: A near-field cortical response recorded from the somatosensory cortex 51

35 Median Nerve SSEP Somatosensory Evoked Potentials (SSEP) Posterior Tibial Nerve Setup: Ground: should be placed on calf Stimulation intensity: ma Stimulation rate (rep rate) = 2-10/second Band-pass filters: Low frequency filter: Cortical: 1-30 Hz Spinal: Hz Peripheral: Hz High frequency filter: Cortical: Hz Spinal: Hz Peripheral: Hz Sweep: 60 milliseconds (6 millisec/division) Number of averages:

36 Somatosensory Evoked Potentials (SSEP) Posterior Tibial Nerve Setup: Recording channels: CPi-FPz CPz-FPz CV5-FPz T12- IC (thoracic spine 12 Iliac Crest) PFd-PFp (popliteal fossa distal-priximal) Stimulation setup: Cathode: should be placed between the tendons of the Palmaris Longus and Flexor Carpi Radialis muscles, 2 cm proximal to the crease of the wrist. Anode: should be placed 2-3 cm distal to the cathode on the palmar surface Somatosensory Evoked Potentials (SSEP) Obligate Waves for Post Tibial & Peroneal nerve SSEPs: PF: Popliteal fossa response is a near-field propagated peripheral nerve response recorded behind the knee. LP: Lumbar Potential is a near-field stationary potential recorded from the thoracolumbar area where the peripheral sciatic nerve enters the Cauda Equina. N34: A far-field subcortical potential recorded from sensory pathway generator in the brainstem and thalamus. P37: A far-filed cortical potential recorded from the somatosensory cortex. 53

37 Somatosensory Evoked Potentials (SSEP) SSEP Data Left Median Right Median Left Post Tibial Right Post Tibial Upper & Lower SSEP Data 54

38 SSEP Data Lumbar Potentials (LP) SSEP Data Modalities Motor Evoked Potentials (TCeMEP) 55

39 Motor Evoked Potentials (TCeMEP) Advantages of TCeMEP: MEPs record corticospinal tract information allowing us to evaluate the functional integrity of motor tracts during high risk portions of the procedure. MEPs are stable waveforms recorded easily with strict TIVA technique. MEP assess the real-time function of voluntary motor pathways in the spinal cord, and reduce the risk of paraplegia. MEPs help detect ischemic changes in the motor cortex, spinal cord, and peripheral motor nerves. Motor Evoked Potentials (TCeMEP) Disadvantages of TCeMEP: MEPs have identified risk factors such as tongue lacerations, and in some populations, risk for seizures. MEPs requires no muscle relaxant during the surgical procedures. 56

40 Motor Evoked Potentials (TCeMEP) Anesthesia: The effect of anesthetic agents is significant on MEP responses by mostly decreasing the amplitude of the responses. All the inhalational agents (Isoflurane, Sevoflurane, Desflurane, Nitrous Oxide) have suppressive effect on MEPs. Muscle relaxant use can abolish MEP responses. If Propofol used in bolus can suppress MEPs. These effects vary from one patient to another depending on various pre-operative factors, such as neurological abnormalities, vascular deficiencies, history of stroke, diabetes mellitus, cerebral palsy, muscular dystrophies, paralysis, etc. The anesthetic effects are always present bilaterally. Epidural D-wave are not effected by inhalational agents but I-waves are suppressed. The ideal anesthesia in Total Intravenous Anesthesia (TIVA) with Propofol and Remifentanil No muscle relaxant. Motor Evoked Potentials (TCeMEP) Alarm Criteria: There are two methods for alarm criteria: All or None method Threshold method There are a number of factors considered before alarming the surgeon including: Use of muscle relaxants Effect of inhalational agents Any pre-existing neurologic conditions Decrease in mean arterial pressure (MAP) below 80 mmhg Related surgical events. 57

41 Motor Evoked Potentials (TCeMEP) TCeMEP Setup: Constant voltage stimulation is used for eliciting MEPs. The pulse width is set to micro-seconds (µs). The stimulation rate is set between 250 Hz 500 Hz. The inter-pulse stimulation interval (ISI) has a range of (recommended ISI between range). The number of trains available for pulse stimulation is between 1 and 9. For epidural recordings, only one pulse should be used, whereas multi-pulse train stimulation (4-7 trains) is used to elicit MEP responses. Voltage between Volts TCeMEP Data 58

42 TCeMEP Data Modalities Electromyography (EMG) 59

43 Electromyography (EMG) Spontaneous electromyography (s-emg) are recorded from the distal muscles. Activity recorded is associated with nerve and nerve root mechanical insult. Used when Spinal Roots or Nerves are at risk Passive recording of activity in muscle (Free-Run EMG / S-EMG) Sub-dermal needle electrodes Active triggering of activity (CMAP/T-EMG)) Monopolar stimulation Bipolar stimulation Tripolar stimulation Electromyography (EMG) s-emg t-emg 60

44 Pedicle Screw Stimulation Reference Current Leak Error fluid, soft tissue, etc Pedicle Screw CURRENT FLOW What is Happening During Pedicle Screw Stimulation? Pedicle Screw Stimulation T-EMG Triggered electromyography are recorded from the distal muscles. Activity recorded is associated with nerve, nerve root and pedicle screw electrical stimulation. T-EMG 4 ma triggered pedicle stimulation response. Indicating probably pedicle wall breach 61

45 Pedicle Screw Stimulation Modalities Train of Four (TOF) 62

46 Train of Four (TOF 4/4) Anesthesia Neurophysiological Monitoring and adequate Anesthesia must mutually coexist in the Operating Room. Ideal Anesthesia is Total Intravenous Anesthesia (TIVA). 63

47 Types of Anesthesia Anatomy 64

48 Anatomy Anatomy 65

49 Spine Surgeries Surgical Spinal Instrumentation Spinal Instrumentation 66

50 Cervical Instrumentation Thoracic Instrumentation 67

51 Lumbar Instrumentation Lumbar Instrumentation 68

52 Growing Rod for Scoliosis Growing Rod for Scoliosis 69

53 Vertical Expandable Prosthetic Titanium Rib (VEPTR) Scoliosis Instrumentation 70

54 Scoliosis Instrumentation Scoliosis Instrumentation 71

55 DLIF/XLIF Instrumentation Ipsilateral nerves at risk need monitoring: Femoral Ilioinguinal Genitofemoral Peroneal Posterior Tibial Ulnar DLIF/XLIF Instrumentation Dilator Dilators are placed separating the fibers of the psoas muscle instead of cutting through it. Retractors are placed. Disc in removed. CAGE implant in placed in disc space Close skin 72

56 DLIF/XLIF Monitoring T-EMG Response Cremaster Response T-EMG Response Jahangiri et al, 2010 Scoliosis What will be the patient s outcome without Intraoperative Neurophysiological Monitoring: What is at Risk? Lower Limbs Motor & Sensory Functions, Bowel & Bladder 73

57 Scoliosis Correction Loss Of Right TCeMEP Trauma What will be the patient s outcome without Intraoperative Neurophysiological Monitoring: What is at Risk? Lower Limbs Motor & Sensory Functions, Bowel & Bladder 74

58 Scoliosis Correction surgery Loss of Right Leg TCeMEP - T11 Cord Ischemia Right Leg Paralysis, Left Leg Burning Pain Challenges in IONM Technical: Stimulation problems Recording problems Physiological: Anesthesia Temperature Mean Arterial Pressure Positioning effects Surgical: 75

59 Challenges in IONM Physiological / Technical Challenges: Compromised blood flow to the extremities: peripheral ischemia, blood clots, BP cuff occlusion Positioning of extremities I.V. Infiltration Hypothermia / Hyperthermia Scalp Edema-impeded stimulus delivery Failure of stimulus delivery (multiple etiologies) Failure of recording electrodes /equipment/ systems Extraneous Artifact Challenges in IONM Hypotension can effect SSEP and TCeMEP signals globally. Ischemia will result in delayed time course. Within the spinal cord the grey matter is most sensitive to ischemia with loss of synaptic activity at 1-2 minutes while conduction in sensory and motor white matter shows alteration in different time. 76

60 IONM MONITORING Effect of Hypotension on SSEP Case # 2: Drop in MAP from 103 to 76 77

61 Anesthesia Vs Surgical Affect Cortical Cortical Cortical Cortical Cervical Cervical Cervical Cortical Cervical Cortical Cervical Anesthesia Event Surgical Event Effect of Ischemia on SSEP Amplitude Reduction 78

62 Positioning Effect: Loss of Ulnar SSEP Jahangiri et al, 2011 Surgical Changes Loss & recovery of lower SSEP 79

63 SSEP Stack Effect of Hypotension on MEP 80

64 Effect of Ischemia on MEP Amplitude Reduction Effect of Ischemia on MEP Amplitude Reduction 81

65 Surgical Changes Drop in left lower MEP and partial recovery during split cord IONM Protocol q Somatosensory Evoked Potentials (SSEP) q Ulnar Nerve SSEP q Posterior Tibial Nerve SSEP q Trans Cranial electrical Motor Evoked Potentials (TCeMEP) q Delt, Biceps, FCU, BR, Thenar, Hypothenar, etc q Iliopsoas, Quad, Tib Ant, Gastroc, AH, AHB, etc q Epidural Evoked Potentials q D-Waves q Electromyogram (EMG) q Spontaneous (s-emg) q Triggered (t-emg) q Train of Four (TOF) q AHB 82

66 Purpose The purpose of IONM is to reduce the incidence of iatrogenic and randomly induced neurological injuries to patients during spinal instrumentation surgical procedures. IONM consequently confers possible benefits at many levels including: Improved patient care Reduced patient neurological deficits Improved surgical morbidity and mortality Reduced hospital stay and medical costs Reduced overall insurance burden Reduce burden on families and doctors Conclusion SSEP along with TCeMEP is recognized as an excellent tool for recognizing surgical and peri-surgical effects and spinal cord ischemia during spinal instrumentation surgeries. 83

67 Thank You Thank You King Abdulaziz Medical City - Riyadh., Saudi Arabia 84

68 Neuromonitoring During Intradural Spinal Procedures Vedran Deletis, MD, PhD 85