When to operate on Adult Scoliosis patients and when to say ‘No’ Frank Schwab, MD Jean-Pierre Farcy, MD New York University School of Medicine

What is Adult Scoliosis?

What is Adult Scoliosis? Coronal plane deformity Sagittal plane deformity Imbalance/malalignment Focal Regional Global Adolescent deformity in an adult AISA De-novo deformity…of aging DDS

Scoliosis Prevalence AIS 2-4% of screened pediatric population Adult >60% of screened elderly population# Demographics : Life expectancy, birth rates…. Significant growth of aging population segment # Schwab et al. SPINE 2005 May 1;30(9):1082-5

Adolescent Idiopathic Scoliosis: surgical treatment Curve severity Cobb angle progression Skeletal maturity Risser sign Curve pattern apex distribution sagittal overhang Classification Lenke King Surgical strategy

Adult Scoliosis Scoliosis: treatment approach Curve severity Cobb angle progression Classification ? Skeletal maturity Risser sign Cosmesis PT Pain Mgmt Bracing Surgery Pain Disability

The aging spine Adult Scoliosis Spine skeletal maturity 30’s disc degen. MRI changes 50’s facet DJD disc collapse Stable spine ankylosis Unfavorable degeneration stenosis spondylo deformity Adult Scoliosis

Progressive collapse Stable ankylosis

Adult Scoliosis / Deformity What are the disability / pain generators ? 98 patients (Schwab,Farcy. SPINE 2004) adult scoliosis, all levels SF-36 radiographic-clinical analysis 325 patients (Schwab, Farcy. SDSG. SRS 2004) thoracolumbar/lumbar scoliosis SRS instrument, ODI radiographic-clinical correlation

Adult Scoliosis : Clinical impact Significant Spondylolisthesis Lateral Subluxation Lumbar lordosis Thoracolumbar alignment Apical level Sagittal Balance (SVA) Not significant Coronal Cobb Age Adolescent vs. de-novo degenerative scoliosis Statistically significant: SRS-22, ODI, SF-12/36

Adult Scoliosis: the disability / pain generators plain radiographs Apical level of deformity (lumbar dominant) Lumbar lordosis T12-S1 Maximal intervertebral subluxation (frontal/sagittal) Sagittal balance (PlC7-S1 offset) Selected for high clinical impact: SRS, ODI, SF-36 (excluding fractures or other pathologies…)

Classification of Adult Deformity Schwab et al. SPINE 2006 Type I thoracic-only curve (no other curves) II upper thoracic major, apex T4-8 III lower thoracic major, apex T9-T10 IV thoracolumbar major curve, apex T11-L1 V lumbar major curve, apex L2-L4 Type K no scoli (<100), principal sagittal plane deformity Lumbar Lordosis A marked lordosis >400 Modifier B moderate lordosis 0-400 C no lordosis present Cobb >00 Subluxation 0 no intervertebral subluxation any level Modifier + maximal measured subluxation 1-6mm ++ maximal subluxation >7mm Sagittal Balance N normal, <4cm positive SVA Modifier P positive, 4-9.5cm VP very positive, >9.5cm

Adult Scoliosis ODI SRS 947 patients: (86% female, 14% male) Average age 48 years (SD 18) Coronal Cobb mean 460 (SD 19) ODI SRS Lordosis Subluxation Global Balance

Adult Scoliosis / Deformity Thus….deformity = disability ? Yes, certain aspects … … Not coronal Cobb angle Coronal/Sagittal Focal: subluxation Regional: loss of lordosis Global: sagittal imbalance Sagittal plane

Adult Scoliosis / Deformity: Why surgery ? Young adult: AISA >500 thoracic >300 lumbar (progressive) Progression with disability Curve progression likely Disability later (potential) More difficult to treat later Depending upon age Surgical risks greater later Cosmetic concerns Weinstein S,. Spine 24(24), 1999

Adult Scoliosis / Deformity: Why surgery ? Older Adult: AISA = DDS Pain/disability failed conservative care Pain unacceptable Disability unacceptable Risk/Benefit ratio - favorable

Adult Scoliosis / Deformity If the justification for surgery is acceptable…. …..when is it really reasonable to operate Don’t do it ? Sure success

Adult Scoliosis / Deformity Not a candidate for surgery: young AISA…no disability, mild/mod curve, happy patient who does not want surgery patient is unlikely to survive surgery patient does not understand risk/benefit unrealistic expectations planned operation is not reasonable experience, team, environment

Adult Scoliosis / Deformity Possibly Excellent candidate for surgery: young AISA…progressive, severe curve (>700) DDS or AISA older adult: Perfectly isolated pain generator, failed extensive non-operative care Well informed, wishes to pursue operative care Excellent health Realistic expectations, highly motivated team has abundant experience only excellent results with planned intervention

Adult Scoliosis / Deformity The common cases: Patient might consider surgery with certain assurances Health is acceptable (not ideal), Pain generators present (there are several), Non-operative care tried (variable participation and response), Expectations are overall rather realistic. The surgeon comfortable with intervention ?

When to operate on Adult Scoliosis patients and when to say No How can we select the best patients for surgery ? (and how to optimize the chances of a successful outcome) non-operative care vs. surgery If surgery…which strategy/approach Specific treatment algorithms lacking few studies to guide us….where is the data ?

Adult Scoliosis: Thoracolumbar / Lumbar Deformity Who gets surgery…and what type ? (n=809) Operative rates Lordosis Lost lordosis vs. good lordosis (B vs. A) 51% vs 37%, p<0.05 Subluxation modifier Marked subluxation vs. none (++ vs. 0) 52% vs. 36 %, p<0.05 Sagittal Balance Well balanced versus marked imbalance (N vs. VP) 39% vs.59%, p<0.05

Adult Scoliosis: Thoracolumbar / Lumbar Deformity Who gets surgery…and what type ? Use of osteotomies Lordosis >400 lordo vs. no lordo : 25% vs. 50% p=0.01 Sagittal balance no imbalance vs. >9.5cm : 25% vs. 53% p=0.01 Surgical Approach Anterior only: no lost lordosis, no subluxation Circumferential: some lost lordosis, marked subluxation Posterior only: marked loss of lordosis, marked sagittal imbalance Fusion to sacrum Lordosis Loss of lordosis more likely fusion to sacrum (p = .041) Sagittal Balance increasing positive balance: more fixation to sacrum. (<4cm: 59%, 4-9.5cm: 80%, >9.5cm: 88%) (all p<0.05)

How about surgical outcomes ? Adult Scoliosis: Thoracolumbar / Lumbar Deformity How about surgical outcomes ? 111patients 1-year follow up 45 patients 2-year follow up Adult Thoracolumbar / Lumbar major curves Surgical treatment, complete data Full-length standing x-rays (0,12,24 months) SRS, ODI, SF-12

2-year Surgical outcome: Lordosis modifier Lumbar Lordosis A marked lordosis >400 Modifier B moderate lordosis 0-400 C no lordosis present Cobb >00 Lordosis modifier ‘C’…most improved

2-year Surgical outcome: sagittal balance (surgical approach) Sagittal Balance N normal, <4cm positive SVA Modifier P positive, 4-9.5cm VP very positive, >9.5cm posterior N with anterior approach did worst (VP posterior-only also not so good) P, VP did best with circumferential fusion

2-year Surgical outcome: sagittal balance (fixation to sacrum) VP without fixation to sacrum got worse P and VP did best with fixation to sacrum (no difference for N)

2-year Surgical outcome: osteotomy or not ? Patients who had osteotomy did better !

Baseline to Two-Year Changes: Significant Interaction ODI / SRS Total Score by lordosis patients with no lordosis (C) greatest improvement, Patients with marked lordosis (A) little or no improvement ODI / SRS Total Score by sagittal balance by surgical approach well balanced least disabled, fused short of sacrum did best very imbalance (VP) most disabled and worse off if not fused to sacrum SF-12v2 / SRS Total Score by Subluxation significant subluxation (++,+) more improvement than no subluxation SF-12v2 PCS / SRS Total score by Osteotomy Status patients with osteotomy had lower baseline scores At 2 years f/u, patients with an osteotomy had higher scores

Follow-up data When is improvement clinically significant ? Adult Scoliosis: Thoracolumbar / Lumbar Deformity Follow-up data When is improvement clinically significant ? Set a bar of 10-point increase in SRS score From 100pt. Scale Assumption of patient perceived improvement Minimal Clinically Important Difference Berven et al.

Minimum 10 point SRS instrument improvement

Minimum 10 point SRS instrument improvement Loss of lumbar lordosis…greater likelihood of clinical success

Minimum 10 point SRS instrument improvement At 2-yr follow up: greater imbalance patients more likely to have successful outcome

Minimum 10 point SRS instrument improvement Patients having osteotomies more likely to have successful outcome

Minimum 10 point SRS instrument improvement Patients with lower baseline scores more likely to achieve significant improvement

When to operate on Adult Scoliosis patients and when to say No How can we select the best patients for surgery ? (and how to optimize the chances of a successful outcome) Can we predict who will have successful surgery ?

Predictive Models Outcome ? Surgical Approach Gender Osteotomy Age Fixation to Sacrum SF-12v2 Physical Component Summary SF-12v2 Mental Component Summary SRS Total Score Oswestry Disability Index Gender Age Apical Modifier Lordosis Modifier Subluxation Modifier Sagittal Balance Outcome ?

Strength of Predictive Models Models to predict Clinical Improvement with Surgery Strength of Predictive Models Outcome Score (meeting the MCID threshold) % Correct Classification by Model Area Under ROC Curve (.80 and above is considered good discrimination) % of Surgical Cases Failing to Meet Criterion SRS Pain 81.1% .864 39.5% SRS Appearance 75.4% .838 33.3% SRS Pain and Appearance 78.1% .845 53.5% SF-12v2 PCS 77.9% .862 47.6%

Follow-up data: Conclusions The winners Greater disability at start (SRS, ODI, SF-12) Male Subluxation >6mm Lost lumbar lordosis <400 Osteotomy Who benefits least minimal baseline disability (SRS, ODI, SF-12) No subluxation, no marked sagittal imbalance Good lordosis, >400 Lack of osteotomy

When to operate on Adult Scoliosis patients and when to say No How can we select the best patients for surgery ? (and how to optimize the chances of a successful outcome) apex Regional deformity SRS, ODI, SF-12 Global sagittal balance Surgical approach osteotomy gender Focal deformity

Adult Scoliosis / Deformity: next steps Refine Classification Predictive outcomes model + SRS ODI SF-12/36 Treatment Algorithm

Thank you….