Carrie E. Bartley

Which Lenke 1a Curves Are at the Greatest Risk for Adding-on... and Why?

Study Design. Multicenter review of prospectively collected data. Objective. The purpose of this study was to evaluate the incidence of distal adding-on and associated risk factors in each of the 2 Lenke 1A curve patterns. Summary of Background Data. Previous work has demonstrated 2 distinct Lenke 1A curve patterns on the basis of the tilt of L4 (1A-L and 1A-R) that are different in form and treatment. Methods. A query of a prospective multicenter adolescent idiopathic scoliosis database identified 195 patients with Lenke 1A curves. Patients were grouped on the basis of the direction of the L4 vertebral tilt: 1A-L (left) and 1A-R (right). The incidences as well as clinical and radiographical risk factors for adding-on were identified for each group. Adding-on was defined as an increase in the Cobb angle of at least 5° and distalization of the end vertebra of the thoracic curve or a change in disc angulation of 5° or greater below the lowest instrumented vertebra from the first erect to 2-year postoperative radiographs. Results. Forty (21%) patients met the criteria for adding-on. The average increase in Cobb angle was 11.9° for those categorized as having adding-on compared with 3.8° in the non–adding-on group. Lenke 1A-R curves were 2.2 times more likely to experience adding-on than 1A-L curves. In the 1A-R curves, patients who added-on were fused at an average of 1.6 levels proximal to the neutral vertebra versus an average of 0.9 levels proximal to the neutral vertebra for the patients who did not add-on (P = 0.023). Patients who added-on were fused at an average of 2.5 levels above stable versus 2.1 levels above stable in those who did not (P = 0.06). Age and skeletal maturity were not identified as risk factors in the 1A-R curves. In 1A-L curves, younger (12.7 vs. 14.7 yr, P = 0.002) and less skeletally mature patients based on Risser grading (70% vs. 14% Risser 0, P = 0.004) were more likely to experience adding-on. Conclusion. Understanding the difference between Lenke 1A-L and 1A-R curve types may be helpful in preventing the adding-on phenomena postoperatively. To prevent adding-on in 1A-R curves, we recommend fusing distally to 1 level above the neutral vertebra or 1 to 2 levels above the stable vertebra. In 1A-L curves, adding-on may simply be a need to balance some lumbar curve progression in a young, skeletally immature patient.

Blood Loss Reduction During Surgical Correction of Adolescent Idiopathic Scoliosis Utilizing an Ultrasonic Bone Scalpel

STUDY DESIGN Retrospective review of prospectively collected data. OBJECTIVES To evaluate blood loss associated with posterior spinal fusion in adolescent idiopathic scoliosis patients performed with and without the use of an ultrasonic bone scalpel (UBS). SUMMARY OF BACKGROUND INFORMATION After using an ultrasonic-powered bone-cutting device with recent Food and Drug Administration approval for use in the spine, the authors perceived a reduction in bone bleeding associated with the cut boney surfaces. METHODS The first 20 patients with adolescent idiopathic scoliosis who underwent posterior spinal fusion using the UBS by a single surgeon were compared with 2 control groups: 1) the 20 most recent prior cases of the same surgeon before beginning use of the bone scalpel; and 2) 20 cases of the same surgeon before using the bone scalpel matched based on Cobb angle magnitudes. Both cases and controls had Ponte-type posterior apical releases; none had an anterior procedure. Patient demographic and surgical data were analyzed using analysis of variance (p < .05). RESULTS Preoperatively, the UBS group was similar to both control groups in terms of primary and secondary curve magnitudes, number of levels fused, number of levels with Ponte release, antifibrinolytic use, and patient age (p > .05). The UBS group had significantly less estimated blood loss (EBL) (550 ± 359 mL), Cell Saver blood transfused (94 ± 146 mL), and EBL per level fused (48 ± 30 mL) than the most recent controls (EBL: 799 ± 376 mL; Cell Saver: 184 ± 122 mL; EBL/level fused: 72 ± 28 mL) and Cobb-matched controls (EBL: 886 ± 383 mL; Cell Saver: 198 ± 115 mL; EBL/level fused: 78 ± 30 mL) (p < .05). Surgical times were equivalent and there were no dural tears in any group. CONCLUSIONS The use of an ultrasonic bone scalpel to perform the bone cuts associated with facetectomies and apical Ponte-type posterior releases resulted in significantly less bleeding compared with cuts made with standard osteotomes and rongeurs, limiting overall blood loss by 30% to 40%.

Maintenance of Thoracic Kyphosis in the 3D Correction of Thoracic Adolescent Idiopathic Scoliosis Using Direct Vertebral Derotation

OBJECTIVES Through a review of prospectively collected data, we sought to analyze the outcomes related to 3-dimensional correction of adolescent idiopathic scoliosis (AIS) after posterior spinal fusion (PSF) and instrumentation using an aggressive combination of correction strategies. BACKGROUND SUMMARY New techniques have been used to address sagittal plane deformity while maximizing coronal and axial correction, including Ponte osteotomy, differential rod over-contouring, and direct vertebral rotation with uniplanar screws. METHODS This is a consecutive single-center series of AIS patients with thoracic curves (Lenke 1 and 2) with 2-year follow-up who underwent PSF and instrumentation with the use of the following correction strategies: segmental uniplanar screws, ultra high-strength 5.5 mm steel rods, aggressive differential rod contouring, periapical Ponte osteotomies, and segmental direct vertebral derotation. Scoliosis Research Society (SRS)-22, radiographic and clinical parameters were evaluated at preoperative and 2-year time points. RESULTS Twenty-six patients were included (mean age 13.6 ± 1.5 years). Preoperative thoracic Cobb measured 52 ± 9°, which improved to 17 ± 4° at 2-year follow-up, resulting in 68 ± 9% correction. The average thoracic kyphosis from T5-T12 did not significantly change (21 ± 10° to 22 ± 5° at 2 years); however, in patients with kyphosis less than 20° preoperatively (avg. 13 ± 5°) kyphosis increased significantly at 2-year follow-up (avg. 20 ± 4°, p<.05). Preoperatively, axial rotation was more than 13° in 21 of 26 cases. At 2-year follow-up, axial rotation remained more than 13° in 4 of 26 cases (p<.01). Rib hump prominence was 17 ± 5° preoperatively, which improved significantly to 10 ± 4° at 2-year follow-up (p<.05). Postoperative SRS domain scores significantly improved in pain (4.3 to 4.7), self-image (3.7 to 4.3), and satisfaction (3.3 to 4.6) (p<.05). CONCLUSION A high degree of coronal correction can be achieved in association with vertebral derotation without sacrificing sagittal plane alignment. High-strength rods aggressively bent to create kyphosis allow both restoration of kyphosis and axial plane derotation in thoracic idiopathic scoliosis.

Surgical Correction of Scoliosis in Patients With Duchenne Muscular Dystrophy: 30-Year Experience.

Background: The natural history of scoliosis in Duchenne muscular dystrophy (DMD) is progressive and debilitating if neglected. The purpose of this study was to evaluate outcomes related to spinal deformity surgery in patients with DMD over a 30-year period. Methods: This was a single center retrospective study of all operatively treated scoliosis in DMD patients over 30 years. Minimum follow-up was 2 years. Owing to changes in instrumentation over time, patients were divided into 2 groups: Luque or pedicle screws (PS) constructs. Radiographic, perioperative variables, pulmonary function test (preoperatively and postoperatively), and complication data were evaluated. Results: There were 60 subjects (Luque: 47, PS: 13). The Luque group was on average 13 years old, 53 kg, and had 7 years of follow-up. Coronal Cobb was 31±12 degrees preoperatively, 16±11 degrees at first postoperatively, and 21±15 degrees at final follow-up (P⩽0.001). Pelvic obliquity was 7±6 degrees preoperatively, 5±5 degrees at first postoperatively (P=0.43), and 5±4 degrees at final follow-up (P=0.77). The majority of this group was fused to L5 (45%) or the sacrum (49%). The PS group was on average 14 years old, 65 kg, and had 4 years of follow-up. Coronal Cobb was 43±19 degrees preoperatively, 12±9 degrees at first postoperatively (P⩽0.001), and 12±8 degrees at final follow-up. Pelvic obliquity was 6±5 degrees preoperatively, 3±3 degrees at first postoperatively (P=0.06), and 2±2 degrees at final follow-up (P=0.053). The majority were fused to the pelvis (92%). Both groups’ pulmonary function declined with time. Both groups had high complication rates (Luque 68%; PS group 54%). The Luque group had more implant-related complications (26%); the PS group had a higher rate of early postoperative infections (23%). Conclusions: Over a 30-year period of operative treatment of scoliosis in DMD, both PS constructs and Luque instrumentation improved coronal Cobb. The PS group had improved and maintained pelvic obliquity. Both groups had high complication rates. Level of Evidence: Level IV—therapeutic.

Safety of pedicle screws and spinal instrumentation for pediatric patients: comparative analysis between 0- and 5-year-old, 5- and 10-year-old, and 10- and 15-year-old patients.

Study Design. Retrospective study. Objective. To investigate the safety of pedicle screws and constructs for infantile and juvenile patients with spinal deformity. Summary of Background Data. Few studies have examined the safety and complication rates associated with the usage of pedicle screw for children younger than 10 years. Methods. Radiographical and clinical data were collected of patients treated with pedicle screws at a single institution. Patients were divided into 2 groups based on age (0–5 yr old, 5–10 yr) and compared with an older cohort of 10- to 15-year-old patients. Patient demographics, screw adjustment, and complication data were collected for each group. Outcomes were analyzed using analysis of variance (P < 0.05). Results. In total, 5054 pedicle screws were analyzed: 176 in the 0- to 5-year-old group (31 patients), 659 in the 5- to 10-year-old group (68 patients), and 4219 in the 10- to 15-year-old group (234 patients). Mean follow-up was 3.1 ± 1.8 years (range, 3 mo–9 yr). There were 7 pedicle screw–associated complications (3 required revision surgery). Overall pedicle screw–associated complication rates were 2.1% per patient and 0.1% per screw. There were no neurological complications associated with misplacement of a pedicle screw. The pedicle screw–associated complication rates per patient and per screw were 3.2% and 0.6% in the 0- to 5-year-old group, 2.9% and 0.3% in the 5- to 10-year-old group, and 1.7% and 0.1% in the 10- to 15-year-old group (P > 0.05). The 5- to 10-year-old group had a significantly higher overall surgically related complication rate (34%) than the 0- to 5-year-old group (7%) and the 10- to 15-year-old group (6%) (P = 0.005), primarily due to the “growth friendly” constructs common in this age group. Conclusion. Pedicle screws can be used for infantile or juvenile patients, although complication rates associated with pedicle screws tended to be slightly higher in the younger groups. Level of Evidence: 3

Predictors of Distal Adding-on in Thoracic Major Curves With AR Lumbar Modifiers.

STUDY DESIGN Retrospective review of prospectively collected data. OBJECTIVE To determine whether the last substantially touched vertebra (LSTV) is a valid lowest instrumented vertebra (LIV) for both Lenke 1 and 2 curve patterns with AR lumbar modifiers, and to identify preoperative risk factors of distal adding-on. SUMMARY OF BACKGROUND DATA Previous studies have recommended selecting the LSTV as the LIV for Lenke 1AR curves (main thoracic curve with A lumbar modifier and L4 tilt to the right (thoracic overhang/King type IV curve). METHODS One-hundred sixty patients with a Lenke 1 or 2 curve pattern and AR lumbar modifier who underwent posterior spinal fusion between 2008 and 2012 were reviewed. All patients had minimum 2-year follow up. Patients were identified with distal adding-on between first erect radiographs and 2-year follow up based on previously defined parameters. Factors predictive of the adding-on phenomenon were identified in a multivariate binary logistic regression model. RESULTS Twenty-seven patients (17%) were identified as having distal adding-on of their primary thoracic curve; however, only 8 of 89 patients (9%) fused to the LSTV developed adding-on (P = 0.005). Three variables were found to be significant predictors of adding-on: LIV proximal to LSTV (odds ratio, OR 3.63; P = 0.01), Risser zero (OR 4.93; P = 0.02), and C7-CSVL distance <2 cm (OR 3.97; P = 0.01). The risk of adding-on increased as the number of predictors increased from 16% with one risk factor to 80% when all three preoperative risk factors were present (P < 0.001). CONCLUSION Choosing the LSTV as the LIV in Lenke 1 and 2 curve patterns with an AR lumbar modifier significantly decreases the risk of distal adding-on. Skeletally immature patients, those fused short of LSTV, and those with relative coronal balance preoperatively are at increased risk of distal adding-on between the initial postoperative visit and 2-year follow up. LEVEL OF EVIDENCE 4.

Does Leveling the Upper Thoracic Spine Have Any Impact on Postoperative Clinical Shoulder Balance in Lenke 1 and 2 Patients

Study Design. Retrospective review of prospective data. Objective. To determine if surgically leveling the upper thoracic spine in patients with adolescent idiopathic scoliosis results in level shoulders postoperatively. Summary of Background Data. Research has shown that preoperatively tilted proximal ribs and T1 tilt are more correlated with trapezial prominence than with clavicle angle. Methods. Prospectively collected Lenke 1 and 2 cases from a single center were reviewed. Clinical shoulder imbalance was measured from 2-year postoperative clinical photos. Lateral shoulder imbalance was assessed utilizing clavicle angle. Medial imbalance was assessed with trapezial angle (TA), and trapezial area ratio (TAR). First rib angle, T1 tilt, and upper thoracic curve were measured from 2-year radiographs. Angular measurements were considered level if ⩽ 3° of zero. TAR was considered level if ⩽ 1 standard deviation of the natural log of the ratio. Upper thoracic Cobb at 2-years was categorized as at or below the mean value (⩽ 14°) versus above the mean. Results. Eighty-four patients were identified. There was no significant difference in the percentage of patients with a level clavicle angle or TAR based on first rib being level, T1 tilt being level, or upper thoracic Cobb being at/below versus above the mean (P < 0.05). There was a significant difference in the proportion of patients with level TA based on first rib angle (P = 0.006), T1 tilt (P ⩽ 0.001), and postoperative upper thoracic Cobb (P = 0.04). The odds ratios of having a level TA were 3.9 (1.4–10.6) if first rib was level, 5 (1.9–12.9) if T1 tilt was level, and 2.6 (1.0–6.3) if postoperative upper thoracic Cobb was ⩽ 14°. Conclusion. Leveling the upper thoracic spine does not guarantee clinically balanced shoulders or clavicles. Trapezial prominence was impacted by leveling T1 and the first rib and by minimizing the upper thoracic curve. How to achieve laterally balanced shoulders postoperatively remains unclear. Level of Evidence: 3

Postoperative Perfection: Ceiling Effects and Lack of Discrimination With Both SRS-22 and -24 Outcomes Instruments in Patients With Adolescent Idiopathic Scoliosis.

Study Design. Review of a prospective database registry. Objective. To compare the Scoliosis Research Society (SRS)-22 and SRS-24 outcomes instruments in terms of scores, rate of ceiling effects, and discriminant ability in patients with pre- and postoperative adolescent idiopathic scoliosis. Summary of Background Data. Despite improvements noted with the SRS-22, the SRS-24 is still occasionally used prospectively and for comparisons with previous studies reporting SRS-24 scores. Previous work has demonstrated that postoperative scores from the 2 versions are not interchangeable. Methods. A multicenter prospective registry of patients who underwent surgical correction of adolescent idiopathic scoliosis was queried for preoperative and 2-year postoperative SRS-22 and SRS-24 scores. Scores were compared between versions and ceiling effects were identified. Groups of deformity severity were created to evaluate discriminant ability. Results. 829 patients were identified. The SRS-22 scores for pain and general function were significantly greater than SRS-24 scores (P < 0.001), whereas the SRS-22 scores were significantly lower than the SRS-24 for self-image (P < 0.001). Preoperative ceiling effect was only noted in 1 domain each. Both versions were able to discriminate between large (80°+) and small (<45°) preoperative curves in all domains and total scores (P < 0.05). Postoperatively, the SRS-22 scores for all shared domains and total score were significantly greater than SRS-24 scores (P < 0.001). Ceiling effects in 5 of 5 domain scores were noted postoperatively for SRS-22 and in 4 of 7 for SRS-24. With a smaller range of deformity postoperatively, only the SRS-22 self-image domain was able to discriminate between large (29°+) and small (⩽11°) residual curves (P < 0.05). Conclusion. Scores obtained by the SRS-22 and the SRS-24 are not translatable despite shared domains. Whereas both versions demonstrated preoperative discriminant ability, postoperative discrimination of residual deformity is lacking in both. Patient-reported outcomes of treatment are crucial in advancing treatment, and improvement in the ability to assess subjective outcomes is essential. Level of Evidence: 3

Performing a Definitive Fusion in Juvenile CP Patients is a Good Surgical Option

Background: In juveniles with progressive curves, there is debate regarding the use of growth friendly implants versus definitive fusion. This study presents outcomes of juvenile cerebral palsy (CP) scoliosis patients who underwent definitive fusion before age 11. Methods: A review of a prospective, multicenter registry identified patients 10 years and younger who had a definitive posterior fusion for their CP scoliosis. Preoperative and postoperative demographic and radiographic changes were evaluated with descriptive statistics. Repeated measures analysis of variance were utilized to compare outcome scores. Results: Fourteen children with a mean age of 9.7 years (8.3 to 10.8 y) and a minimum of 2 years follow-up (range 2 to 3 y) were identified. The mean preoperative curve magnitude and pelvic obliquity was 84±25 degrees (range 63 to 144 degrees) and 25±14 degrees, respectively. All patients were skeletally immature with open triradiate cartilage. Three patients had unit rods with wires while the rest incorporated pedicle screws. Immediately postoperation, the average major curve was 25±17 degrees (P⩽0.001, 71% correction rate). At most recent follow-up, the average major curve increased to 30±18 degrees (P⩽0.001) for a 65% correction rate. Pelvic obliquity improved to 4±4 degrees (84% correction, P⩽0.001) immediately postoperation and to 6±5 degrees (P=0.002) at latest follow-up for a 76% correction rate. None of the patients required revision surgery for progression. From pre to most recent follow-up, the CPchild Health outcome scores improved from 47 to 58 (P=0.019). One patient had a deep infection, and 1 patient had a broken rod that did not require any further treatment. Conclusions: Progressive scoliosis in juvenile CP patients requires the surgeon to balance the need for further growth with the risks of progression or repeated surgical procedures. Our study demonstrates that definitive fusion once the curves approach 90 degrees results in significant radiographic and quality of life improvements, but further follow-up is needed to determine whether those results remain after skeletal maturity. Level of Evidence: Level IV—therapeutic.

The Relationship Between Apical Vertebral Rotation and Truncal Rotation in Adolescent Idiopathic Scoliosis Using 3D Reconstructions

STUDY DESIGN Retrospective review of prospective data. OBJECTIVES To evaluate the relationship between absolute apical vertebral rotation (AVR) evaluated with upright 3D imaging and angle of trunk rotation (ATR) before and after surgery for thoracic and lumbar curves in adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA New imaging technology allows for improved radiographic assessment of the degree of AVR pre- and postoperatively through 3D spine models created from biplanar, simultaneous spine radiographs. METHODS A prospective registry was queried and identified 55 AIS patients with major thoracic or major thoracolumbar/lumbar curves who underwent posterior spinal fusion. All patients had biplanar upright imaging of their spine and ATR measurements assessed via scoliometer pre- and postoperatively. RESULTS There were 33 major thoracic and 22 major lumbar curves. The mean Cobb angles for thoracic and thoracolumbar/lumbar curves were 54° ± 10° and 47° ± 8° preoperatively, and 11 ± 6° and 12 ± 7° postoperatively. The differences in the mean preoperative ATR measurements for both major curve types was not statistically significant; however, the difference in AVR between thoracic curves (13 ± 6°) and lumbar curves (22 ± 7°) was significant (p < .001). There was a significant decrease in the ATR and AVR for both thoracic and thoracolumbar/lumbar curves (p < .001) postoperatively. A significant correlation between ATR and AVR was found only for the major thoracolumbar/lumbar curves (p < .001). The relationship between ATR and AVR changes for both curves was not statistically significant. CONCLUSION ATR measured via scoliometer strongly correlates with 3D measurements of AVR in both thoracic and lumbar curves before and after surgery for AIS. No significant relationship was found between the changes in ATR and AVR due to surgery. Postoperatively, greater clinical rotational deformity remains in the thoracic spine compared to the lumbar spine, despite greater apical vertebra axial plane correction in thoracic curves. LEVEL OF EVIDENCE Level II, diagnostic.STUDY DESIGN Retrospective review of prospective data. OBJECTIVES To evaluate the relationship between absolute apical vertebral rotation (AVR) evaluated with upright 3D imaging and angle of trunk rotation (ATR) before and after surgery for thoracic and lumbar curves in adolescent idiopathic scoliosis (AIS). New imaging technology allows for improved radiographic assessment of the degree of AVR pre- and postoperatively through 3D spine models created from biplanar, simultaneous spine radiographs. METHODS A prospective registry was queried and identified 55 AIS patients with major thoracic or major thoracolumbar/lumbar curves who underwent posterior spinal fusion. All patients had biplanar upright imaging of their spine and ATR measurements assessed via scoliometer pre- and postoperatively. RESULTS There were 33 major thoracic and 22 major lumbar curves. The mean Cobb angles for thoracic and thoracolumbar/lumbar curves were 54° ± 10° and 47° ± 8° preoperatively, and 11 ± 6° and 12 ± 7° postoperatively. The differences in the mean preoperative ATR measurements for both major curve types was not statistically significant; however, the difference in AVR between thoracic curves (13 ± 6°) and lumbar curves (22 ± 7°) was significant (p < .001). There was a significant decrease in the ATR and AVR for both thoracic and thoracolumbar/lumbar curves (p < .001) postoperatively. A significant correlation between ATR and AVR was found only for the major thoracolumbar/lumbar curves (p < .001). The relationship between ATR and AVR changes for both curves was not statistically significant. CONCLUSION ATR measured via scoliometer strongly correlates with 3D measurements of AVR in both thoracic and lumbar curves before and after surgery for AIS. No significant relationship was found between the changes in ATR and AVR due to surgery. Postoperatively, greater clinical rotational deformity remains in the thoracic spine compared to the lumbar spine, despite greater apical vertebra axial plane correction in thoracic curves. LEVEL OF EVIDENCE Level II, diagnostic.