Adolescent Idiopathic Scoliosis

Transcription

1 Adolescent Idiopathic Scoliosis Surgical Treatment Comparisons By: Dr. Alex Rabinovich and Dr. Devin Peterson

2 Options 1. Pedicle Screws versus Hooks 2. Posterior versus Anterior Instrumentation 3. Open versus Thoracoscopic Approach

3 Pedicle Screws vs. Hooks Comparative Analysis of Pedicle Screw Versus Hook Instrumentation in Posterior Spinal Fusion of Adolescent Idiopathic Scoliosis. (Kim, Lenke, Cho, Bridwell) Spine 2004,29: Comparative analysis of pedicle screw and hook instrumentation in posterior correction and fusion of idiopathic thoracic scoliosis. Eur Spine J (2002) 11:

4 Design Pedicle Screws vs. Hooks Retrospective matched cohort study 26 patients with screws and 26 patients with hooks. Matched for: Age and Risser Grade Lenke curve type Number of fused vertebrae Identical operative approach. Outcomes: Pre-op, Immediate and 2 years Post-op. Radiographic, PFT, OR Time, EBL, Cost, Clinical Score (SRS-24).

5 Pedicle Screws vs. Hooks ALL p = NS Screws (26 patients) Hook (26 patients) Age / / Gender 19 F, 7 M 23 F, 3 M Lenke Type 1) Main Thoracic 2) Double Thoracic 3) Double Major 4) Triple Major 6) Major Thoracolumbar 14 type 1 7 type 2 1 type 3 2 type 4 2 type 6 14 type 1 7 type 2 1 type 3 2 type 4 2 type 6 Fused vertebra / /- 2.0 Approach PSF = Posterior TPL = Thoracoplasty ICBG = Iliac bone graft APSF = Anterior + PSF 18 PSF + TPL 4 PSF + ICBG 4 APSF 18 PSF + TPL 4 PSF + ICBG 4 APSF Risser 3.1 +/ /- 2.0

6 Pedicle Screws vs. Hooks Operative Approach: Posterior fusion with open OSI frame Pedicle Screws Pedicle screw insertion with fluoroscopy assistance and triggered EMG responses. 2 rod technique (5.5 mm CDH or 5 mm MMI) Average 6 thoracoplasties (Kim et al. Spine 2004,29:333) Free hand pedicle screw (Raynor et al. Spine 2002;27:2030) EMG with screws

7 Pedicle Screws vs. Hooks Hooks 2 rods 5.5 mm CDI, CDH or MMI. Laminar, Transverse Process, and/or Pedicle Hooks were used as anchors. Wisconsin wires occasionally used. Average 6 thoracoplasties. Correction forces as per standard approach. Post op: no brace for any group. Physical therapy program 4-6 months until (n) ADL

8 Pedicle Screws vs. Hooks

9 Pedicle Screws vs. Hooks

10 Pedicle Screws vs. Hooks Screw Group Hook Group P FVC (% predicted) Pre-op Post 2 yrs FEV1 (% predicted) Pre-op Post 2 yrs SRS- 24 Post 2 yrs NS OR Time 341 min 337 min NS Blood Loss 879 ml 896 ml NS Cost (US $) 14,200 9,228 < Neurological Deficits 0 0 NS Avg. LIV below LEV Fusion length shorter with screws Saved vertebra (0.8)

11 Pedicle Screws vs. Hooks Conclusions: 1. Coronal Plane Change: Screws offer stronger construct with 3 column purchase and longer moment arm. Screws offer more correction and maintenance of correction with equal global spine balance. 2. Sagittal Plane Change: Screws offer more correction and maintenance of correction of thoracic kyphosis with equal global spine balance. Hooks did not maintain correction, and returned to pre-op values of thoracic kyphosis.

12 Pedicle Screws vs. Hooks Conclusions: 3. PFT: Screws showed significantly better results in % predicted FVC and FEV1 from pre-op to 2 yrs post-op. 4. SRS-24, Fusion Level, EBL, OR Time, Cost: Screws saved on average 0.8 vertebra Screws also COST more in US $ SRS-24, EBL, and OR Time were not significant No neurological deficits between the groups

13 Options 1. Pedicle Screws versus Hooks 2. Posterior versus Anterior Instrumentation 3. Open versus Thoracoscopic Approach

14 Posterior vs. Anterior Instrumentation Sagittal Plane Analysis of Adolescent Idiopathic Scoliosis. The Effect of Anterior Versus Posterior Instrumentation. (Rhee, Bridwell, Won, Lenke, Lawrence, ) Spine 2002;27: Comparison of Anterior and Posterior Instrumentation for Correction of Adolescent Thoracic Idiopathic Scoliosis. (Betz, Shufflebarger, Lenke, Lawrence, ) Spine 1999;24:

15 Posterior vs. Anterior Instrumentation Design: 110 consecutive pts (Average age 14 y.o.) All curve patterns Single Institution, 2 Surgeons Average 3 yrs follow up No Randomization, Surgeons Discretion for Approach Single Thoracic Curve -> Anterior or Posterior Double Major, Double Thoracic, Triple Major -> Posterior Single Thoracolumbar or Lumbar -> Anterior

16 Posterior vs. Anterior Instrumentation 1. Anterior thoracic, n=23 2. Posterior thoracic, n=40 1 patient had anterior release and fusion (no hardware) 3. Anterior thoracolumbar, n=27 4. Posterior thoracolumbar, n=20 6 patients had anterior release and fusion (no hardware) ** The reason for anterior release in posterior groups is for stiff curves >72 o **

17 Posterior vs. Anterior Instrumentation Anterior Surgical Approach Single rod screw construct. 3.5 mm. Autologous bone-filled titanium mesh cages for anterior column support Posterior Surgical Approach Open OSI frame, with 5.5 mm CDH X 2 Hooks, Screws and Wisconsin Wires used Autologous bone graft (iliac crest or thoracoplasty) in each case.

18 Posterior vs. Anterior Instrumentation Outcomes Pre-op, 2 month post-op, >2 years post-op 1. C7 Plumbline (mm) 2. Proximal Junctional Measurement (angle) 3. Distal Junctional Measurement (angle) 4. Thoracolumbar Junction (T10 - L2) (angle) 5. Thoracic Kyphosis (T5 - T12) (angle) 6. Lumbar Lordosis (T12 - S1) (angle) Positive values = Kyphosis, Negative values = Lordosis 7. Pseudoarthrosis 8. Implant Failure

19 Posterior vs. Anterior Instrumentation Results 4 pts had implant failure and/or revision 2 broken anterior instrumentations 1 distal hook pullout 1 posterior revision for extension to lumbar curve Fusion Levels (average) Anterior = 6.8 (single thoracic) Posterior = 10.7 (single/double thoracic) Anterior = 4.3 (thoracolumbar) Posterior = 11.9 (thoracolumbar)

20 Posterior vs. Anterior Instrumentation Results C7 Plumbline (mm) The Anterior Thoracic group had more kyphosis from pre-op to final follow up. But all p=ns between the groups. Proximal Junctional Measurement (angle) Anterior Thoracic and Thoracolumbar had significantly less PJM Kyphosis than Posterior Thoracic and Thoracolumbar. * PJM = Cobb angle b/w most proximal implant and 2 segments cephalad (sagittal) * C7 Plumbline = Horizontal distance of C7 plumbline to posterior-superior corner of S1 (sagittal)

21 Posterior vs. Anterior Instrumentation Results Thoracic Kyphosis (T5 T12) Posterior groups got less kyphosis than Anterior groups pre-op and at final follow up (p=0.04) Thoracolumbar Junction (T10 L2) No significant difference between the 4 groups in post-op and final follow up measurements. All groups retained angle. Lumbar Lordosis (T12 S1) Anterior and Posterior Thoracic had similar lordosis Anterior and Posterior Thoracolumbar had significantly more lordosis than just Thoracic (pre-op vs. final follow up)

22 Posterior vs. Anterior Instrumentation Results Distal Junctional Measurement (angle) DJM was not significantly different between the 4 groups relative to pre-op and final follow up. Clinical Outcomes: No siginificant difference from commentary. * DJM = Cobb angle b/w most distal implant and 2 segments caudal (sagittal)

23 Posterior vs. Anterior Instrumentation Discussion 1. No siginificant clinical difference. 2. On average vertebra saved with Anterior approach 3. More hardware failure with Anterior approach 4. Posterior instrumentation showed largest PJM kyphosis. Which may lead to cervical kyphosis. 5. Anterior showed more Thoracic Kyphosis than Posterior instrumentation. But at final follow up, all Thoracic Kyphosis was within normal range (20-40 o ). Anterior release increases flexibility and has potential for hyperkyphosis.

24 Posterior vs. Anterior Instrumentation Discussion 6. Lumbar lordosis was enhanced with any thoracolumbar instrumentation. 7. DJM was not significantly different. 8. C7 Plumbline moves anterior with anterior instruments. 9. Crankshaft occurs more frequently with posterior fusion of younger patients (Risser <3), but can also occur with Anterior fusion and Posterior overgrowth. 10. Coronal balance equal in both groups (1999 article) 11. Loss of correction (Coronal view), Ant > Post. (1999)

25 Options 1. Pedicle Screws versus Hooks 2. Posterior versus Anterior Instrumentation 3. Open versus Thoracoscopic Approach

26 Open vs. Thoracoscopic Approach Results of Thoracoscopic Instrumented Fusion versus Conventional Posterior Instrumented Fusion in Adolescent Idiopathic Scoliosis Undergoing Selective Thoracic Fusion. (Wong, Hee, Yu) Spine 2004;29: Anterior thoracoscopic spine release in deformity surgery: a meta-analysis and review. (Arlet) Eur Spine J (2000) 9 (Suppl 1):S17-S23

27 Open vs. Thoracoscopic Approach Design Retrospective review 31 consecutive female patients Average age = 14.3 years Average follow up = 44 months

28 Open vs. Thoracoscopic Approach 19 patients posterior fusion with hooks Standard 2 rod technique, no screws, rib or iliac crest bone grafting, No brace post-op, AAT post-op 12 patients anterior thoracoscopic approach 1 lung ventilation, 4-5 small incisions, Disc-annulus excised to posterior longitudinal ligament, partial anterior longitudinal ligament excision. Morcellized rib autograft used for intervertebral spacers. Fluoroscopic guided screw insertion. TLSO orthosis for 3 months, or until fusion is achieved.

29 Open vs. Thoracoscopic Approach Open Post - Hooks Scope Ant - Screw Age Risser NS NS EBL 368 ml 313 ml OR Time 252 min 415 min < ICU Stay 1.5 days 2.6 days 0.01 Hospital Stay 7.5 days 8.3 days IV Pain Meds 2.9 days 3.3 days NS Complications 0 Lobar Collapse Winged Scapula P

30 Open vs. Thoracoscopic Approach Open Post - Hooks Scope Ant -Screw P Coronal Angle Pre-op NS Right bend NS Flexibility 44% 37% NS 1 wk post-op mth post-op >2 yrs post-op Overall NS

31 Open vs. Thoracoscopic Approach Sagittal Angle Open Post - Hooks Scope Ant -Screw P Thoracic Kyphosis (T5 - T12) (T5 - T12) Pre-Op NS 1 wk post-op mth post-op >2 yrs post-op Overall NS Lumbar Lordosis (T12 S1) (T12 S1) Pre-Op NS 1 wk post-op mth post-op >2 yrs post-op Overall NS

32 Open vs. Thoracoscopic Approach Number of segments fused: Significant less (P<0.001) fused segments with Anterior Scope vs. Posterior Hooks (average 3.5). At most recent radiological review, all patients had evidence of fusion, with no hardware failure and no pseudoarthrosis.

33 Open vs. Thoracoscopic Approach Discussion: Posterior Advantages: Stable fusion, sagittal control, PFT benefit, low pseudoarthrosis rate, no need for post-op bracing Posterior Disadvantages: Osteoporotic segments, Adjacent segment disease, Paraspinal nerve denervation, Neurological deficits Anterior Advantages: Mechanical advantage because less fusion for same correction %, More kyphosis potential, Anterior Disadvantages: Hardware failure, increased loss of correction, pseudoarthrosis,

34 Open vs. Thoracoscopic Approach Discussion: Anterior Thoracoscopic vs. Posterior Hooks Less blood loss Less fused segments Same Coronal and Sagittal angle correction and maintenance of post-op fusion for at least 2 years. More potential for kyphosis correction, but if initial kyphosis >20o, then risk of hyperkyphosis is greater. Same IV Analgesia usage More OR Time (> 2 hours difference) (more $) More ICU and Hospital stay (more $) Higher learning curve, hence more $ for training. More complications (anecdotal evidence)

35 Future Studies 1. Posterior Screws vs. Anterior Open/Thoracoscopic 2. Anterior Open vs. Anterior Thoracoscopic 3. Posterior Screws vs. Ant/Post Combined

36 Thank You

37 Scoliosis in Pediatrics - Quick Review Idiopathic Scoliosis Most common, females, Right Thoracic Curve > 10 o is threshold for scoliosis (Cobb Angle) Asymptomatic, cosmetic issues, gait, back pain progression relates to age, curve type and size. Risser 0-1 with > 20 o, 65% risk progression Risser 2-4 with > 20 o, 20% risk progression Full neurological exam mandatory X-ray: 3 foot standing spine AP/Lat

38 Scoliosis in Pediatrics - Quick Review Risser grades 0-5. Degree of bony fusion of the iliac apophysis, from grade 0 (no ossification) to grade 5 (complete fusion).

39 Scoliosis in Pediatrics - Quick Review Idiopathic Scoliosis Treatment Approach < 25 o, observe o, immature, brace if progression >5 o /yr o, immature, brace > 40 o, immature, surgery > 50 o, mature, surgery Double major curves >60 o, surgery Crankshaft Phenomenon: Immature patients (Risser 0-1) with posterior fusion -> anterior spine overgrows -> hyperlordosis + rotation.