211 - Minimally Invasive Treatment-based Classification of Diseased Lumbar M...

#211 Minimally Invasive Treatment-based Classification of Diseased Lumbar Motion-segment

MIS Techniques and Outcomes

Poster Presented by: S. Osman

Author(s):

S.G. Osman (1)

(1) American Spine Center, Orthopedics, Frederick, MD, USA

Abstract

Background: Multiple minimally invasive spine approaches and techniques have been developed in recent years. While the disease processes affecting the spinal motion-segment have remained largely the same, surgical treatment options have changed radically and not necessarily in an organized fashion. This is inevitable given the rapid evolution of the technology. The current diagnostic techniques, also evolving, have helped us appreciate in minute details of the disease pathoanatomy. A comprehensive classification method accounting for all anatomical participants in the pathology, and tailored to treatment options, is necessary.

Purpose of the Study: To develop a comprehensive, treatment-orientated classification of lumbar spinal motion-segment disease.

Materials and Methods: Review of the literature for pathology of spinal motion-segment; anatomy of motion-segment; review of spinal imaging studies and currently practiced treatment options for various combinations of pathoanatomy of spinal motion-segment disease. Contributors to spinal motion-segment disease are the intervertebral disc, facet joint, ligamentum flavum and mal-alignment. The degrees of abnormalities in these entities were coded as follows:

Alignment:

A0 = Normal

A1 = Grade I spondylolisthesis

A2 = Grade II spondylolisthesis

A3 = Grade III & IV spondylolisthesis

D = Disc:

D1= Global bulging disc

D2 = Contained disc herniation

D3 = Free fragment disc herniation

F= Facet joint

F0 = Normal facet

F1 = inferior articular process enlargement

F2 = superior articular process enlargement

F3 = both inferior and superior articular processes enlargement

F4 = both inferior and superior articular processes enlargement and cyst formation

L = Ligamentum flavum

L1= normal/minimal hypertrophy

L2= Moderate hypertrophy

L3= Severe hypertrophy

a, b, c = disc and foraminal heights

a = Normal disc and foraminal heights

b = Mild to moderate loss of disc and foraminal heights

c= Moderate to severe disc and foraminal heights

Results: This classification presents multiple possible combinations of the severity of motion-segment disease in a tabular form. Code D2A0L2FO (a) represents contained disc herniation; normal alignment; mild thickening of the ligamentum flavum; and normal facet joint. This combination may be treated with transforaminal arthroscopic discectomy using various tools. Code D1A2L1F2 (b) represents a bulging disc with mild to moderate loss of disc and foraminal heights; grade I spondylolisthesis; normal ligamentum; and hypertrophic superior articular process. Depending on the symptom complex, this combination may be treated with transforaminal endoscopic decompression ± MIS interbody fusion and instrumentation to stabilize the spine. Code D3A4L3F4 represents free-fragment herniation, grade 3 or 4 listhesis, severely hypertrophic ligamentum and massively hypertrophic facet with cyst formation. This combination would mostly likely benefit from open approach.

Conclusion: A treatment-orientated, standardized classification of spinal motion-segment disease is necessary in light of current treatment options and availability of sophisticated preoperative imaging techniques. Such a classification will allow standardization of treatment options for various combinations of the pathological processes. Surgical options can be upgraded based on a standardized classification. This in turn will help minimize confusion for those who want to learn, and facilitate growth in the minimally invasive technology which is currently hampered by the payers who consider most of these procedures experimental.

Table 1