Fusion or non-fusion in the painful / degenerative spineThe Asian surgeon’s view: Clinical study of application of non-fusion interspinous implants for degenerative lumbar disease

Chunde LiMD, Professor

Director, Orthopaedic Surgery DepartmentPeking University First Hospital

Beijing, China

Non fusion interspinous implants

• A very attractive alternative to spinal fusion– Especially for younger patients – Minimally invasive– Provides flexible support of the lumbar spine– Avoids adjacent segment degeneration

Biomechanics• Restores and preserves disc height • Allows shock absorption and load sharing • Preserves anatomy with minimal bone and

ligament removal • Acts to treat back pain while preserving the

mobility and anatomy of the treated segment• Allows restoration of disc height and reduction of

the load on the disc and the facets

Classification• STATIC (NONCOMPRESSIBLE) DEVICES

• X STOP (St Francis Medical, Alameda, California)• ExtenSure (NuVasive, San Diego, California)• Wallis (Abbott Spine, Austin, Texas)

• DYNAMIC (COMPRESSIBLE) DEVICES• Coflex (Paradigm Spine, New York, New York)• DIAM (Medtronic Sofamor Danek, Memphis, Tennessee)

X-STOP

ExterSure

Wallis (1st Generation)

Wallis (2nd Generation)

Coflex

Coflex rivet

DIAM

Indication• Wallis：

– Low-back pain that accompanies degenerative lesions of grade II, III and IV (Pfirrmann MRI classification) in the following indications:

• Massive herniated disc in young adults • Recurrent herniated disc • Herniated disc accompanying an L5 sacralization transitional

anomaly• Degenerative disc disease at a segment adjacent to fusion• Degenerative lesions with or without Modic 1• Lumbar canal stenosis treated by laminotomy (not by

complete laminectomy)

Indication• Coflex

– Radiographically-confirmed moderate to severe stenosis with neural element compromise resulting in claudication and / or radicular symptoms

Indication• Coflex

– Instability (rotational or vertical) associated with recurrent herniations

– Large voluminous primary disc herniations– Adjunctive therapy for stabilizing levels above or

below a fusion (“topping-off“) in the same procedure to minimize adjacent level degeneration

Indication• Coflex

– Conjunctive therapy:• Combination with nucleus replacement• Combination with total disc replacement with mild to

moderate facet degeneration

Contra-indication• Wallis：

– Grade V degenerative lesions in the MRI classification of Pfirrmann

– Spondylolisthesis– Osteoporosis– Nonspecific low back pain– Modic 2 and Modic 3

Clinical study of application of non-fusion interspinous implants for degenerative lumbar disease at Peking University First Hospital

General Information• From September 2007 to September 2008• 68 cases with degenerative lumbar diseases

were treated with interspinous implants• Male： 39 cases• Female：29 cases• Age：26-71 yrs (average 49.3 yrs）

IndicationIndication Wallis Coflex Total

DDD 2 0 2LDH 14 15 29DLSS 9 12 21

Combined with fusion to avoid ASD 6 4 10

Combined with fusion to avoid

multiple-segment fusion

3 3 6

Total 34 34 68

MethodsThe clinical results were assessed by：– VAS of pain on lumbar and lower limbs– Lumbar JOA score – Prolo functional score

Methods• the radiological results were assessed by：

– Lumbar X ray – Dynamic X ray

• Implant positon• Segmental lodosis • Segment movement degree

– Lumbar MRI or CT • Disc nutrition • LDH recurrence

Results• 64 cases obtained complete follow-up • Follow up periods ：8-18 months (average 13.6

months）Lumbar pain

VASLower limbs

pain VASLumbar JOA

scoreProlo function

scorePre-op 4.9±3.3 7.2±2.8 13.4±4.9 4.2±2.8

final follow up 1.7±1.5① 1.3±1.0① 23.5±3.1① 8.6±1.4①

① P<0.01 compared with pre-op

Segment lodosis and segment movement • Segment lodosis angles:

– 15.4±4.2°(final follow-up)– Less than 19.6±4.7° (pre-operation)

• Segment movement degree ：– 10.3±4.5°(final follow-up)

Segment lodosis angle

Segment movement degree

Complications• No spinous process fracture• 2 cases with mild displacement of implants• 2 cases with lumbar disc herniation recurrence

and received second operation

Implant displacement

Post-op 1 month Post-op 6 month

LDH recurrence and received second operation

Pre-op Post-op 4 month

Case 1, DDD• Female

• 51 yrs

• L4-5 DDD

• L4-5 interspinous fixation with Wallis

Pre-op MRI

Post-op 1 month

Post-op 3 months

Post-op MRI

Pre-op Post-op 12-month

Case2 DDD and Modic I change• Male, 32 yrs• DDD• L3/4, L4/5 Modic I change• L3/4, L4/5 interspinous fixation with Wallis

Pre-op

Pre-op MRI

Post-op 1 month

Post-op 1-year MRI (Modic I to Modic II)

T1 phasePre-op Post-op

Post-op 1-year MRI (Modic I to Modic II)

T2 phasePre-op Post-op

Case 3, DLSS

• Male, 39 yrs

• L4-5 DLSS

• L4-5 decompression and interspinous fixation with Coflex

Pre-op

Pre-op MRI

Post-op 3-month

Post-op 7-month

Post-op 7-month: Dynamic X-ray Lodosis Angle:27° Lodosis Angle:14°

Post-op 12-month

Post-op 12-month: Dynamic X-ray

Lodosis Angle:29°Lodosis Angle:14°

Case 4: LDH

• Female, 45 yrs• L4/5 LDH• L4/5 Discetomy and interspinous

fixation with Wallis

Pre-op

Pre-op MRI

Post-op 1-month

Post-op 12-month

Post-op 12-month: Dynamic X-ray Lodosis Angle:13° Lodosis Angle:20°

Post-op 18-month

Case 5：Combined with fusion to avoid multiple-segment fusion

• Male 56 yrs– L5 Spondylolysis、Spondylolisthesis grade Ⅰ– L3-4 DLSS

• Treatment：– L5-S1 decompression and PLF– L3-4 decompression and interspinous fixation with

Wallis

Pre-op

Pre-op• Double oblique

positions:L5 Spondylolysis

Pre-op MRI

Post-op 1 week

Post-op 3-month

Post-op 12-month

Conclusion• The application of non-fusion interspinous

implants for degenerative lumbar diseases is still in the early stages

• The selection of indication is very important• Its efficacy and safety are evidenced by short

time follow-up

Thank You Very Much！