Disclosure Cervical Spinal Disorders Morio Matsumoto Morio - PDF document

11/8/2013 Pedicle Screw Fixation for Disclosure Cervical Spinal Disorders Morio Matsumoto Morio Matsumoto received honorarium for Associate Professor Director of Spine Section Dept . Of Orthopaedic Surgery, Keio University, lecture from Medtronic Sofamor Danek Japan. Japan Cervical Pedicle Screws First used for C2 Fx Report of 13 cases with middle and lower Le conte P 1964 cervical spinal trauma treated with PS Borne GM 1984 Anatomical study and report of 3 patients with articular mass fracture Borne GM J Spinal Disord 1994 J Neurosurg. 1984 1

11/8/2013 Cervical Pedicle Screws Advantages of PS Constructs C2 and 7 Good stabilization and bone union Widely used because of anatomical Excellent correction of deformities feasibility if VA anomaly is absent and its maintenance C3-6 Short fusion Rarely used because of Eliminating need of anterior procedures, anatomical limitation due to the existence of VA postop. external fixation Biomechanical Superiority Indication Unstable spine caused by trauma, tumors, PS > LMS in pull-out strength RA, DSA after hemodialysis, CP Ladd JE et al. Spine 1997 Lack in intact laminae or lateral masses PS-rod : greater reduction in axial load by previous surgery, trauma, tumors, transfer in anterior column than LMS-rod severe bone fragility, etc. Dunlap BJ et al. ESJ 2010 Fixed cervical deformities PS>LMS Pull-out strengths and bone- (kyphosis, O-C subluxation, etc, ) screw interface after cyclic loading Johnston TL et al. Spine J 2006 2

11/8/2013 Pedicle Morphology- Axial Plane Contra-indication of PS placement Karaikovic EE Spine 1997 Chazono M JNS 2006 Lee DH Eur Spine J 2011 An absent or extremely small C4 C3 C2 pedicle(outer diameter<4mm) 5 to 6 mm 5 to 6 mm 8 mm A pedicle destroyed by tumors etc. 40-50 15-30 40-50 C5 C6 C7 Anomalies of the vertebral artery Infection in the posterior elements 5 to 6 mm 5 to 6 mm 6 to 7 mm 30-35 35-40 40-50 Internal Morphology of Human Cervical Pedicle Morphology Sagittal Plane Pedicles Panjabi et al. Spine 2000 Ebraheim E Spine 1996 Karaikovic EE Spine 1997 Chazono M JNS 2006 Lee DH Eur Spine J 2011 Medial cortical shell (1.2 – 2.0 mm) ; C4 2-5 1.4 to 3.6 times as thick -3 -0 C5 -4 - -1 as lateral cortical shell C2 C6 -4 - -2 (0.4 – 1.1 mm) 20-35 C3 C7 7-13 PS more likely to penetrate lateral cortex 3

11/8/2013 Preoperative Imaging Dominancy of VA Tortuous pathway of VA in severe OA and RA Lt side dominant 70% Individual variations++ (Tomashino, JNS 2010) • Morphology of Pedicles • Anatomy of Vertebral Artery Fine cut CT Safer More dangerous CT / MR angiography VA and Transeverse foramen Wide Exposure to the outer (Tomashino A, et al JNS 2010) border of LM for PS placement • Important for identification of anatomical • The VA entry was found at C7 in 2.4 and landmarks 5.5% of the patients’ right and left sides. • for prevention of pushback from PVM • Transverse foramen occupied by VA was the greatest in C-4 and C-7 (37.1 and 74.2%, respectively). • C-4 and C-7 can be considered critical levels for CPS placement. 4

11/8/2013 Drilling of the posterior cortex of LM Starting Points proposed by Abumi allows for more flexible screw trajectory (J Spinal Disord, 1994) PS Placement under fluoroscopic guidance Starting Points (lateral view) Lee DH Karaikovic EE. Pedicle tapping Eur Spine J 2011 J Spinal Disord 2000 probe C2: 2.3 + 1.4 C3: 2mm C3: 0.8 + 1.0 C6 C4: 0.8 + 0.9 C4: 2mm screw C5: 1.9 + 1.3 Pedicle C5: 2mm insertion sounder A C6: 3.3 + 1.5 C6: 2mm C7 2mm lateral C7: 4.2 + 1.3 2mm superior Courtesy of Prof. Abumi of midpoint of LM 5

11/8/2013 Methods to Enhance Accuracy Steep Learning Curve of PS Placement Laminoforaminotomy Yoshimoto H et al. ESJ 2009 Miller RM Spine 1996 Pedicle axis view technique Yukawa Y, JNS 2006 % of misplacement Navigation systems Early phase 12.0% Kotani Y, JNS 2003 Rath SA. JNS 2008 Middle phase 7.0% Ito Y, et al. JNS 2008 Late phase 1.1% Ishikawa Y JNS 2011 O-arm based navigation Ishikawa Y (JNS 2011) Key slot technique (90-100 PS/ phase) Lee SH (Jspinal Disord 2012) Navigated PS Placement Pedicle axis view technique Yukawa, JNS Spine 2006 Enhance accuracy but Kotani Y, JNS 2003 not eliminate misplacement Rath SA. JNS 2008 (major perforation 1.2-2.8%) Ito Y, et al. JNS 2008 Ishikawa Y JNS 2011 C6 C6 Rt Rt Courtesy of Dr.Yukawa, 6

11/8/2013 Indication Percutaneous Transmuscular Insertion for patients with thick nuchal muscles Unstable spine caused by trauma, Useful to prevent lateral perforation caused tumors, RA, DSA after hemodialysis, CP by pressures from nuchal muscles Lack in intact laminae or lateral masses by previous surgery, trauma, tumors, severe bone fragility, etc. Correction of fixed cervical deformities (kyphosis, O-C subluxation, etc, ) 80y/o male with ASH and OPLL Fracture dislocation at C5-6 Quadriparesis after fall 50 y/o Male after fall Frankel C paralysis Slight distraction to prevent spinal cord compression due to traumatic disc herniation (Abumi, J Neurosurg 2000) 7

11/8/2013 Hybrid Construct C7 Extension Fracture Dominant Side: Lateral Mass Non-dominant Side: Pedicle Dominant PS LMS Safer R L L R 72 Female RA Severe Neck pain Progressive myelopathy LMS PS 8

11/8/2013 Immediately after surgery 52y/o male with severe neck & arm pain Relief of neck pain Metastasis of Follicular Thyroid Carcinoma 9

11/8/2013 3 years 1 year Mild neck pain without neurological deficit 32 patients with metastatic cervical spinal tumors undergoing reconstructive surgery using PS. 4 upper cervical lesions, 28 subaxial lesions. Posterior alone in 25 Combined AP in 7 Neck pain improved in all cases. 83% presented neurologic improvement Anterior column reconstruction could be avoided in 78% Chordoma 65 y/o M Recurrence after partial resection twice Preoperative Embolization of lt VA & Ion-beam radiation Intractable neck pain and quadriparesis 10

11/8/2013 X ray and CT-scan after surgery 24y/o female with GCT at C2 Neck pain and quadriparesis 11

11/8/2013 2 nd nd stage e Operat eration on (Anterio erior) 1 st st stage e Operat eration on (posterio erior) Mandibl ble e splitting ng approa oach ch Curreta tage and Fusion with PS Dislodge gemen ent and retrieval val of Iliac No recurrence at 5 years after surgery crest st graft (1 month h p.o.) follow owed d by addition onal al posteri erior or bone graft 12

11/8/2013 Neurofibromatosis 1 with dystrophic changes Neck Pain & Mild myelopathy (23y/o Female) O-T4 fusion followed by ASF C2-C5 with fibula strut 13

11/8/2013 Cervical myelopathy due to Athetoid CP Posterior decompression & PS fusion (58 y/o Male) No recurrence of myelopathy 7 years po Cervical Myelopathy Due to Congenital Anomalies at the upper cervical spine (17 y/o Male) Spine 2013 17 patients who underwent midline C2 laminoplasty and posterior spinal fusion using PS. Kyphosis 11.0 ° improved to 1.5 ° p.o. Solid bony fusion achieved in all cases 13 % PS misplacement with no sequal Laminoplasty and PS provided strong internal fixation and improved neurological function 14

11/8/2013 70 y/o Female with Pseudotumors Neurologically improved w/o neck pain • Myelopathy worsened after C1 laminectomy 4years after O-C2 fusion • O-C fusion was conducted with improvement of myelopathy • Regression of pseudotumor and reduction of clivoaxial angle was observed Complications Indirect Decompression using PS System Abumi K et al Spine 2012 • Reduction in clivoaxial angle and cervicomedullary angle Yoshihara H et al JNS 2013 • Reduction of vertical subluxation Abumi K et al, Spine 1999 Screw misplacement Ding X et al, Eur Spine J 2011 (w/wo sequel) 2-30% Vertebral artery injury 0.15-0.9% controlled by bone wax etc. Nerve root injury 0.3-1.5%  screw misplacement screw removal if necessary  iatrogenic foraminal stenosis (C5) addition of foraminal decompression Implant failure rare<5% 15

11/8/2013 Perforation Rates of Cervical Pedicle Screw Screw Misplacement Insertion by Disease and Vertebral Level Uehara M, et al, The Open Orthopaedics Journal, 2010 • Transient radiculopathy Major perforation rate in 53 patients treated using PS under navigation Per Disease • CSM (15.0%) • CP (10.0%) • DSA (4.6%) • RA (3.4%) • Spine tumor (0 0%) Per Level • Sporadic reports of VA injury resulting in C2(6.7%), C3(8.2%), C4(14.0%), C5(3.1%), cerebral infarction (Onishi E, Spine 2010) C6(2.4%), C7(2.2%) • Opinions against PS Use for Balance between Needs and Potential Risks Relatively Common Diseases Kast et al ESJ 2006 Risks Needs Reserve this technique for use in highly selected patients with clear indications Severe fixed deformity Complications and for highly experienced spine Destructive disease VA injury surgeons Tumor Nerve root injury Trauma Hasegawa K et al Spine 2008 No indication in cases of typical CSM and OPLL if a potential risk of vertebral artery or nerve injury is taken into Skills account. 16

11/8/2013 Summary Keio University Hospital PS is useful for treatment of trauma, severely destructive diseases, tumors, and deformities. Preoperative precise evaluation of bony and neurovascular anatomy is mandatory. PS is associated with potentially catastrophic complications PS use for degenerative diseases is debatable. 17