Spine made easy Spondylolisthesis Waleed Awwad MD FRCSC

Spine made easy Spondylolisthesis Waleed Awwad. MD, FRCSC Assistant professor consultant spine surgeon

History

Spondylolisthesis • Displacement of one vertebra in relation to another vertebra below • Incidence: • Affects 5 -7% of US population • 85% at L 5 • 10% at L 4 • Natural history: • Progression observed in children • Adults, 8 -30% present after 4 th decade

Spondylolysis Spondylolisthesis

Classification • Etiology: • Wiltse classification • Marchetti-Bartolozzi classification • Severity: • Meyerding classification

Marchetti-Bartolozzi classification I. Developmental • • High dysplastic with lysis or with elongation Low dysplastic with lysis or with elongation II. Acquired • • Traumatic (due to acute or stress fracture) After surgery (caused by direct or indirect surgery) Pathological (due to local or systemic pathology) Degenerative (found in primary or secondary degenerative conditions)

Wiltse classification

Wiltse classification • Type I dysplasia (congenital).

Dysplastic changes • Proximal sacral rounding • Trapezoidal L 5 • Vertical sacrum • Junctional kyphosis • Compensatory hyper-lordosis

Wiltse classification • Type II isthmic.

Wiltse classification • Type III degenerative.

Wiltse classification • Type IV post traumatic.

Wiltse classification • Type V pathological.

Wiltse classification • Type VI iatrogenic

Meyerding grading system

Assessment • X-rays: • Anteroposterior • Lateral • Oblique views

Assessment • X-rays: • Anteroposterior • Lateral

Assessment • X-rays: • Anteroposterior • Lateral • Oblique views Pedicle “eye” Ascending process (ears) Transverse process (nose) Spondylolysis (collar) Descending process (legs)

Assessment • X-rays: • • Anteroposterior Lateral Oblique views CT scan

Assessment • X-rays: • • • Anteroposterior Lateral Oblique views CT scan Bone scan

Assessment • X-rays: • • • Anteroposterior Lateral Oblique views CT scan Bone scan MRI

Spinal canal stenosis: facet joint orientation “Sagittal” “Coronal”

Spinal canal stenosis: facet joint orientation • Facet orientation > 45 degrees is 25 times more likely to develop degenerative spondylolisthesis most commonly at L 4/5 • Women: Men = 5: 1 • African-American women > Caucasian women

Spinal canal stenosis: facet joint orientation Buttress Sagittal orientation of facet joints

Spinal canal stenosis: facet joint orientation Buttress Decompression and removal of this buttress can create instability when load is applied

Spinal canal stenosis: facet joint orientation Coronal orientation of the facet joints enables decompression of neural elements without creating instability

Spinal canal stenosis: synovial cysts • Indicates presence of significant joint and synovial pathology • Need to excise synovium or immobilize the segment in order to prevent recurrence

Spinal canal stenosis: facet joint fluid or gas Fluid Gas Fluid or gas in the facet joint of a patient indicates the presence of instability

Spinal canal stenosis: facet joint fluid or gas Supine Standing

Spinal canal stenosis: intervertebral disc height

Spinal canal stenosis: intervertebral disc height

Spinal canal stenosis: intervertebral disc height Undercutting facetectomy

Spinal canal stenosis: intervertebral disc height Expect loss of disc height over time

Spinal canal stenosis: intervertebral disc height Adequate decompression initially Recurrence of foraminal compromise over time

Spinal canal stenosis: intervertebral disc height

Assessment—Meyerding Classification

Assessment—slip angle Standard method of measurement Method used when inferior end plate of L 5 is irregular

Measurement • Slip angle

Measurement • Slip angle • Normally Negative or 0

Measurement • Sacral inclination • Normally > 30 degrees

Measurement • Pelvic incidence • • • PI = PT + SS Mean children 47 degrees Mean adults 57 degrees Low PI loss of lordosis High exaggerated lordosis

Low PT High SS High PT Low SS

Sagittal alignment • Stance • Gait • Head over pelvis • Hips and knees

Risk factors for progression • • • Young age (progression is rare after 20 years) Female Ligamentous laxicity > 50% slippage > 10% slip angle L 5 - S 1 instability Trapeaoidal L 5 Dome- shaped upper sacrum Less likely to progress with decreased disk space and an Anterior sacral lip

Treatment • Majority can be managed nonoperatively: • • • NSAIDS Physical therapy Pars interarticularis injection Facet injections above defect (communicates with defect) Nerve root blocks for root symptoms

Treatment • Indications for Surgery: • Persistant back pain which interfere with activities of daily living • Symptomatic with failed conservative treatment • Significant progression • Grade III or higher with >55 degrees slip angle • Neurologic deficits • Acute traumatic

Treatment • Surgery may be indicated to treat persistent radiculopathy and/or back pain when origin of pain is localized to the spondylolisthesis level • PLF results in good outcome if fusion in situ performed • Where reduction is undertaken, 360 o fusion preferred

Surgical options • Fusion in situ and decompression • Decompression and reduction • Posterior lateral fusion and anterior column support

Gill laminectomy • Nerve root decompression • Removal of lamina of the affected level • May lead to increased instability • Radicular symptoms may persist unless decompression is accompanied by fusion to stabilize the segment in order to prevent ongoing neural irritation

High grade • Gaines resection • Sacral osteotomy • Fibular strut - Bohlman • Increased risk of neurological compromise (L 5 nerve root) with attempted reduction

Take-home messages • The majority of patients with a spondylolysis or listhesis are asymptomatic • Initial treatment should focus on activity modification and core stabilization • Surgery indicated for patients with: • Failure of nonoperative treatment • Significant or progressive deformity • Neurological compromise • The aim of surgery is to: • Decompress neural elements and preserve function • Reduce lumbosacral kyphus • Achieve fusion