mis posterior cervical fusion - foundation for orthopaedic … · 2018-04-16 · posterior cervical...

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MIS Posterior Cervical fusion

James B. Billys, MDAssociate Professor Department of Orthopaedics USF

Florida Orthopaedic Institute

Director of Research

Phillip Spiegel Orthopaedic Research Laboratory at FORE

Deborah Warren RN CCRC

Castellvi Spine 2016

Disclosures

Medtronic

Nuvasive

Alphatec

St. Jude

Centinel

Who did I forget?


Case JS46 y/o male 72” 205 lbs.

C/o neck pain with weakness numbness and tingling in parascapular areas.

S/P ACDF C4‐C7 1 year ago


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Case JS

CT scan .


Case JS


.

JSpinal Disord Tech. 2015 Mar;28(2):41‐6. doi: 10.1097/BSD.0b013e31829a37ac.Do CT scans overestimate the fusion rate after anterior cervical discectomy and fusion?Park DK1, Rhee JM, Kim SS, Enyo Y, YoshiokK.Author information: 1*Department of Orthopedic Surgery, William Beaumont Hospital, Royal Oak, MI †Department of Orthopedic Surgery, Emory Spine Center, Emory University, Atlanta, GA ‡Department of Orthopedic Surgery, Seoul Spine Institute, InjeUniversity Sanggye‐Paik Hospital, Seoul, Korea §Department of Orthopedic Surgery, Wakayama Medical University, Wakayama, Japan.AbstractDESIGN:This study is a radiographic analysis.OBJECTIVE:To compare the fusion rates after anterior cervical discectomy and fusion (ACDF) using x‐rays versus computerized tomography (CT).BACKGROUND:Although fusion status may be obvious when evaluating ACDFs performed in the remote past, determining the presence of a solid fusion at earlier time points after ACDF is often ambiguous but a necessary part of practice. Commonly used tools include radiographs and CT scans. Currently, there is no gold standard imaging modality to determine fusion status.METHODS:Twenty‐two patients status post‐ACDF (cortical allograft with anterior plates) at 34 levels with CT scans and dynamic x‐rays obtained at 3, 6, and 12 months postoperatively were included. Four spine surgeons blinded to the time point independently determined fusion status according to the criteria.RESULTS:On the basis of the x‐ray criteria, the fusion rates were 26%, 41%, and 65% at 3, 6, and 12 months, respectively, postoperatively. On the basis of CT criteria, the fusion rates were 79%, 79%, and 91% at 3, 6, and 12 months, respectively. There was a significant difference in the predicted fusion rate at each time point comparing x‐ray versus CT criteria. In addition, at 3 months, 41% of the levels (11/27) thought to be fused by CT criteria demonstrated >1 mm motion on dynamic x‐rays. At 6 months, 33% (9/27) of the levels thought to be fused by CT demonstrated persistent motion of ≥1 mm. At 12 months, 23% (7/31) of the levels considered fused by CT still had persistent motion.DISCUSSION:X‐ray criteria for fusion, which incorporate both static and dynamic factors, predicted lower fusion rates at each time point when compared with CT scans, which evaluate only static factors. Depending on the time point, anywhere from 23% to 41% of levels thought to be fused by CT criteria demonstrated persistent motion on dynamic x‐rays. Although <1 mm motion is not a sufficient criteria for fusion by itself, levels demonstrating >1 mm motion are less likely to be solidly fused. Thus, we conclude that CT scans may overestimate the fusion rate during the early stages of ACDF healing with cortical allograft, and that CT scans alone may not accurately determine fusion status. Reliable determination of fusion may thus require dynamic information obtained from flexion‐extension x‐ray in association with high‐resolution static information from CT.

PMID: 23732186 [PubMed ‐ indexed for MEDLINE]


X ray Criteria for fusion‐static factors‐dynamic factors

CT‐ staticX ray predicted lower fusion rates vs CT

Conclusion: 33‐44% thought to be fused on CT‐demonstrated >1mm motion on Flex/Ext X ray

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Flex/ Ex Motion


C4‐5 remains stable C5‐6 10.6 mm movement C6‐7 8.7 mm movement

Technology Overview

Posterior Cervical Intervertebral Fusion Device

Tissue sparing

Indirect decompression

Stabilization and fusion


Mechanism of Action

Decompresssymptomatic nerve roots through facet distraction


10.0mmPre‐Op

13.2mmPost‐Op

DTRAX

StabilizeBy fusing the joint, Preventing translation

93% Fusion Rate @ 1 Year98% Fusion Rate @ 2 Years Implants packed with bone to promote fusion

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Indirect Decompression


20%+ Increase in Foraminal Area *

1.Buckley et. al Foramen distraction effectiveness of the DTRAX facet screw system 2.Tan et. al Effect of machined intra‐facet allograft on foraminal height and area

Pre‐Op 10.0mm

Post Op 13.2mm

Significant Stabilization


0

0.5

1

1.5

2

2.5

3

Lat Bending Flex‐Ex Axial Rota on

DTRAX

ACDF‐Plate

Preventing Facet Translation Limits Segmental Motion Similar to Plated ACDFUnpublished, Patwardhan et. al

How I use it


Adjacent Level, Non-Union after ACDF, facet arthrosis

Supplemental Stabilization & Posterior fusion with ACDF

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Case JS – what we did


DTRAX Stability

Biomechanical Stability of a Novel Posterior Cervical Fusion DeviceAvinash G. PatwardhanLoyola University Chicago, Edward Hines Jr. VA Hospital, 2014 (unpublished)

Evaluate acute stabilization for:• DTRAX vs ACDF, Single Level• ACDF vs ACDF + DTRAX, Single and 2-level

Conclusions• DTRAX Cervical Cage stabilization is comparable to the

ACDF construct in flexion-extension, lateral bending and axial rotation in a single level fusion.

• Supplementing ACDF with DTRAX will significantly increase stabilization in single and 2-level fusion.


Materials and Methods 7 Fresh frozen cervical spine cadavers

1.5 Nm moments applied in flexion/extension, lateral bending and axial rotation


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Study Design, Test Sequence

A. Intact (C2‐T1)

B. +C5‐C6 DTRAX

C. +C6‐C7 plated ACDF


Study Design, Test SequenceD. +C6‐C7 DTRAX

E. + C3‐C5 plated aCDF

F. + C3‐C4 and C4‐C5 DTRAX


Range of Motion

DTRAX and ACDF are similar in reducing range of motion


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DTRAX + ACDF, 1 Level

DTRAX stabilization significantly increase effectiveness of ACDF alone in 1‐level setting


Treatment of ACDF Non-Union


Is Posterior Fusion the Answer?


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Does it Fuse?

Clinical Data

Facet Surface Area comparable to Interbody Space

Fusion Distance in Facets shorter compared to Interbody Space


Does it Fuse?


Outcomes of this study


Patient Reported Improvement

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Retrospective Study

Retrospective Study of all subjects with Posterior Fusion with DTRAX

10 patients: 3 women 7 men

All s/p ACDF with Psuedoarthrosis and recurring pain symptoms


Materials and Methods

Collecting VAS (5 points‐ neck, right and left shoulder and right and left arm) Neck Disablilty IndexSF 12Neuro/Motor exam radiographs

Earliest subject is 22 months out. Early data suggests good relief of arm and shoulder pain


Outcomes 7 of the 11 patients are out 12 mos or betterFusion Rate is 100%

2 Complications 1 patient was re‐operated on for migration of the original DTRAX (before adding the bone screw) (first patient)


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Outcomes

2. Cage placed too close to nerve root‐


Is one of these good?

DTRAX Cases

Case 1; DBMale 49y/o 6’1” 225lbs.

Sheet/metal welder; electro mechanic

c/o neck pain and parascapular pain w/ h/w and n/t on both upper extremities

Post ACDF C5‐C7 (1998 and 1999) and broken hardware revisions (2002) outside of FOI

Posterior laminectomy/cervical spinal cord stimulator (July 2013)

Post RFA C2‐C6 (September 2013)


Case DB (pre-op)


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Case DB (pre-op)


Case DB

Case 1; DB Procedure

Preoperative Diagnosis:

C7‐T1 radiculopathy

Facet arthropathy

Cerival Post‐Laminectomy Syndrome

Procedures Performed:

C7‐T1 Posterior Fusion

Insertion of DTRAX cervical cage


Case DB (post-op)


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Case DB Post-op fusion


DTRAX Cases

Case 2; MC

Female 50y/o 5’1” 110lbs.

Sales manager

c/o neck pain w/ h/a and muscle tension

S/P C5‐C7 ACDF (October 2012)

Pseudoarthrosis


Case MC (pre-op)


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Case MC (post-op)


Case MC (post-op)


C5‐C6

C6‐C7

Case MC (post-op)


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Case MC (post-op)


Several months later

Symptoms returned‐

MRI revealed anterolisthesisof C7 on T1

And modic changes at C4‐C5


Case MC


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Summary

Our preliminary data at 1 year demonstrates that percutaneous distraction and fusion using the DTRAX facet system is a safe and effective treatment option with cervical psuedoarthrosis.

Thank you


JBB FOI Tampa2015

JBB FOI Tampa2015

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mis posterior cervical fusion - foundation for orthopaedic … · 2018-04-16 · posterior cervical...

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