The posterior approach for lumbar and thoracolumbar adolescent idiopathic scoliosis: posterior shortening and pedicle screws

Is It Enough to Stop Distal Fusion at L3 in Mild to Moderate Lenke 5C Adolescent Idiopathic Scoliosis Patients?

OBJECTIVE

There has been no definitive conclusion on the selection of the lowest instrumented vertebra (LIV) in Lenke 5C adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to evaluate whether it is enough to stop distal fusion at L3 in mild to moderate Lenke 5C AIS patients with posterior selective lumbar fusion, Ponte osteotomies and segmental direct vertebra rotation and to analyze the risk factors for postoperative complications in patients selecting L3 as the LIV.

METHODS

A retrospective review was conducted on 106 Lenke 5C AIS patients who underwent corrective surgery in our institution from 2010 to 2021, with a minimum 2-year follow-up. The LIV was L3 or L4. According to the LIV, patients were initially divided into Group I (the LIV was L3) and Group II (the LIV was L4). Then, Group I was further divided into a complication group and a non-complication group. Demographics, radiological parameters, postoperative complications, and clinical outcomes were recorded. Univariate analysis and multivariate logistic analysis were used to identify the risk factors for postoperative complications in patients with L3 as the LIV.

RESULTS

There were no significant differences in the demographics, radiological parameters, postoperative complications, or clinical outcomes between Group I and Group II (p > 0.05), and the outcomes were satisfactory in both groups. The main postoperative complications were distal adding-on (11 cases), coronal imbalance (16 cases), proximal junctional kyphosis (2 cases), and internal fixation failure (4 cases). Logistic regression analysis revealed that age and postoperative C7-CSVL were independent predictors of postoperative complications when selecting L3 as the LIV.

CONCLUSION

Terminating the distal fusion level at L3 was practical for mild to moderate Lenke 5C AIS patients. For patients selecting L3 as the LIV, younger patients should be cautious, and maintaining postoperative coronal balance is necessary for avoiding postoperative complications.

Postoperative Coronal Imbalance in Lenke 5C Adolescent Idiopathic Scoliosis: Evolution, Risk Factors, and Clinical Implications

OBJECTIVE

To explore the changes in coronal imbalance (CIB) in Lenke 5C adolescent idiopathic scoliosis (AIS) after posterior selective fusion surgery and determine their implications for surgical decision-making.

METHODS

One hundred twenty patients were categorized according to the preoperative coronal pattern (type A, coronal balance distance [CBD]<20 mm; type B, CBD≥20 mm and coronal C7 plumbline [C7PL] shifted to the concave side of the curve; type C, CBD≥20 mm and C7PL shifted to the convex side of the curve). CIB group (CIB+) was defined as having a CBD≥20 mm at the 2-year follow-up.

RESULTS

Compared to type A patients, the prevalence of postoperative CIB was higher in type C patients both immediately postoperative (22% vs. 38%, p<0.05) and at the final follow-up (5% vs. 29%, p<0.05), whereas type A patients showed a greater improvement in CBD (9 of 12 vs. 6 of 24, p<0.05) at the final follow-up. The majority of patients in all groups had recovered to type A at the final follow-up (96 of 120). The proximal Cobb-1 strategy reduced the incidence of postoperative CIB (1 of 38) at the 2-year follow-up, especially in preoperative type C patients. Multivariate logistic regression analysis revealed that type C and overcorrection of the thoracolumbar curve were risk factors for CIB at the 2-year follow-up (p=0.007 and p=0.026, respectively).

CONCLUSION

Patients with type C CIB in AIS exhibited unsatisfactory restoration, with 29% of them exhibiting CIB at the final follow-up. The selective fusion strategy of proximal Cobb-1 may reduce the risk of postoperative CIB especially when the preoperative coronal pattern is type C.

Ponte osteotomies for treatment of spinal deformities: they are not all made equal

PURPOSE

To compare surgical outcomes of Ponte's osteotomies for treatment of adolescent idiopathic scoliosis (AIS), Scheuermann's kyphosis (SK), and adult scoliosis (AdS).

METHODS

We conducted a retrospective review of patients with AIS, SK, and AdIS who underwent posterior spinal instrumented fusion (PSIF) at our Institution from January 2019 to December 2022. Demographics, imaging, and intraoperative data (including number of osteotomies performed, blood losses, surgical timing, and complications) were extracted from patient charts.

RESULTS

A total of 80 patients (62 AIS, 7 SK, and 11 AdS) were enrolled in the study. All patients were treated with a PSIF and a total of 506 Ponte osteotomies were performed (5.8 ± 4.1, 9.3 ± 2.4, and 7.5 ± 2.5 average osteotomies per patient in the AIS, SK, and AdS group, respectively; p = 0.045). Average time per osteotomy was 6.3 ± 1.5 min in the AIS group, and 5.8 ± 2.1 and 8.7 ± 4.0 in the SK and AdS group, respectively (p = 0.002). Blood loss was significantly smaller in the SK group (8.6 ± 9.6 ml per osteotomy) compared to AIS group (34.9 ± 23.7 ml) and AdS group (34.9 ± 32.7 ml) (p = 0.001). A total of 4 complications were observed in the AIS group (1.1%) and 2 complications in the AdS group (2.4%), but this was not statistically significant.

CONCLUSIONS

Our study shows that Ponte's osteotomies are safe and effective in surgical treatment of AIS, SK, and AdS. Blood loss and execution time per osteotomy are significantly smaller in the SK group compared to AIS and AdS. No significant differences were noted in terms of complications between the three groups.

Is the morphology of the apical pedicles influenced by apical rotation or the coronal curve magnitude in adolescent idiopathic scoliosis?: a radiographic assessment

INTRODUCTION

Asymmetry in pedicle anatomy is most distinctly noted around the apex of the curve. The correlation of pedicle dysmorphia with apical vertebral rotation (AVR) and coronal Cobb angle (CCA) has not been studied.

OBJECTIVE

To establish whether pedicle dysmorphism is linked to curve magnitude CCA and the AVR in adolescent idiopathic scoliosis (AIS).

METHODOLOGY

Preoperative plain whole spine standing radiographs and non-contrast computed tomography (CT) scans of 25 AIS patients that were operated at a single centre from 2013 to 2019 were retrospectively reviewed by 3 independent co-investigators. CCA was noted on the standing radiograph, whereas the AVR was measured on the axial cuts of CT scan. Pedicle morphometric measurements were performed for apical and periapical pedicles. These included apical vertebra (when present), 2 vertebrae above (U1 and U2) and below (B1 and B2) the apex vertebra/disc. The pedicle morphometric measurements were performed on CT scans. We assessed the transverse pedicle diameter, transverse cancellous channel diameter, sagittal pedicle diameter, pedicle length and pedicle axis length. Correlation tests between various pedicle morphometric measurements, AVR and the curve magnitude (Cobb angle) was performed by the Pearson correlation test.

RESULTS

The apex of the major curve was in the thoracic spine in 20 patients, thoracolumbar in three patients and in the lumbar spine in two patients. The mean Cobb angle was 61.5 ± 9.3° and the mean AVR was 28.4 ± 17.8°. A positive correlation was noted with the AVR for U1 concave pedicle length (r = 0.45, p = 0.03), pedicle axis length of the U2 concave pedicle (r = 0.6, p = 0.04), transverse pedicle diameter of the convex apical vertebrae (r = 0.82, p = 0.00009) and the convex apical transverse pedicle diameter (r = 0.80, p = 0.002). A negative correlation with the AVR was noted for U2 convex pedicle length (r = - 0.51, p = 0009), transverse cancellous channel diameter of the U2 concave pedicle (r = - 0.42, p = 0.04) and apical concave pedicle (r = - 0.78, p = 0.002) and the sagittal pedicle diameter for the convex pedicle of U2 (r = - 0.45, p = 0.03) and apex(r = - 0.59, p = 0.04). The Cobb angle did not show a significant correlation with any of the pedicle measurements at any of the levels on the convex and the concave sides.

CONCLUSION

Pedicle asymmetry and dysmorphism demonstrate a morphometric association with the apical vertebral rotation than the curve magnitude. The pedicle length and the pedicle axis length increase on the concave apical and periapical region with increase in AVR. The transverse cancellous channel diameter significantly decreases on the concave apical region with the increase in AVR. The sagittal pedicle diameter decreases on the convex side with the increase in AVR.

Risk factors and clinical impact of persistent coronal imbalance after posterior spinal fusion in thoracolumbar/lumbar idiopathic scoliosis

OBJECTIVE

Persistent coronal imbalance (PCI) can develop postoperatively. In this study, the authors aimed to clarify the risk factors and clinical impact of PCI after posterior spinal fusion (PSF) in idiopathic scoliosis (IS) patients with a major thoracolumbar/lumbar (TL/L) curve.

METHODS

Data on 108 patients with Lenke type 5C or 6C IS who underwent PSF with a minimum of 2 years of follow-up were retrospectively analyzed. PCI was defined as coronal imbalance persisting 2 years after surgery. Radiographic parameters and clinical outcomes were compared between the PCI (+) and PCI (-) groups. Multivariate regression analyses of associated factors were performed to determine the risk factors for PCI.

RESULTS

Of the 108 patients, 48 (44%) had immediate postoperative coronal imbalance, and 10 of these patients (9%) had coronal imbalance persisting 2 years after surgery. The PCI (+) group had significantly worse postoperative subtotal and satisfaction scores than the PCI (-) group. Preoperative apical vertebral translation (AVT) of the TL/L curve (AVT-TL/L) and postoperative coronal balance (CB) were identified as independent risk factors for PCI. The cutoff values of preoperative AVT-TL/L at 49.5 mm (area under the curve [AUC] 0.835, p = 0.001, 95% CI 0.728-0.941, sensitivity 70.0%, specificity 72.4%) and those of postoperative CB at -27.5 mm (AUC 0.837, p < 0.001, 95% CI 0.729-0.945, sensitivity 78.6%, specificity 70.0%) were used to predict PCI. In selective fusion cases, older age (OR 2.110, 95% CI 1.159-3.842, p = 0.015), greater preoperative AVT-TL/L (OR 1.199, 95% CI 1.029-1.398, p = 0.020), and less postoperative CB (OR 0.855, 95% CI 0.743-0.983, p = 0.027) were independent risk factors for PCI.

CONCLUSIONS

Preoperative AVT-TL/L and postoperative CB are important parameters for predicting PCI. PCI adversely affects postoperative clinical outcomes. In selective fusion surgery, PCI tends to occur in older patients due to reduced flexibility and compensatory abilities.

Complication risks and costs associated with Ponte osteotomies in surgical treatment of adolescent idiopathic scoliosis: insights from a national database

PURPOSE

Risks of Ponte osteotomies (POs) used for posterior spinal fusion (PSF) for Adolescent Idiopathic Scoliosis (AIS) are challenging to assess because of the rarity of complications. Using a national administrative claims database, we evaluated trends, costs and complications associated with PO used in PSF for AIS patients.

METHODS

Using ICD-9/CPT codes, we identified patients (ages 10-18) with AIS who underwent PSF (± PO) between 2007 and 2015 in the IBM® MarketScan® Commercial Databases. Costs and trends of POs were evaluated. Odds of neurological complications and readmissions within 90 days and reoperations within 90 days and 2 years were assessed.

RESULTS

We identified 8881 AIS patients who had undergone PSF, of which 8193 had 90-day follow-up and 4248 had 2-year follow-up. Overall, 28.8% had PO. Annual rate of POs increased from 17.3 to 35.2% from 2007 to 2015 (p < 0.001). Risk-adjusted multivariable logistic regression demonstrated no relationship between POs and neurologic complications (p = 0.543). POs were associated with higher odds for readmission (1.52 [1.21-1.91]; p < 0.001) and reoperation (2.03 [1.13-3.59]; p = 0.015) within 90 days, but there were no differences in the odds of reoperation within 2 years (p = 0.836). Median hospital costs were $15,854 (17.4%) higher for patients with POs (p < 0.001) and multivariable modeling demonstrated POs to be an independent predictor of increased costs (p < 0.001).

CONCLUSION

Annual rate of POs increased steadily from 2007 to 2015. POs were not associated with increased odds of neurological complications but had higher costs and higher rates of readmissions and reoperations within 90 days. By 2 years, differences in reoperation rate were not significant.

LEVEL OF EVIDENCE

III.

Postoperative proximal junctional kyphosis correlated with thoracic inlet angle in Lenke 5c adolescent idiopathic scoliosis patients following posterior surgery

Background

Proximal junctional kyphosis is a common complication after posterior fusion in patients with adolescent idiopathic scoliosis and is correlated with postoperative changes of thoracic kyphosis. In lenke 5c patients, higher postoperative LL and spontaneous change of TK may produce an effect on final PJK. However, no studies has been performed to evaluate the correlation of PJK with thoracocervical parameters in patients with AIS.

Methods

Data from 98 patients who underwent posterior fusion for Lenke 5C AIS with 2 years of follow-up were retrospectively reviewed. Patients in the extended fusion group underwent fusion at levels higher than upper-end vertebra + 2 (n = 38), and those in the thoracolumbar/lumbar (TL/L) fusion group underwent fusion at UEV + 2 or lower (n = 60).

Results

During an average follow-up of 38.1 months, 23 of 98 patients developed PJK. The extended fusion group had a higher incidence of PJK than the TL/L fusion group (14/38 vs. 9/60, respectively; P = 0.01) and a significantly greater decrease in thoracic kyphosis than the TL/L group (P < 0.01). Patients with PJK had a significantly larger preoperative thoracic inlet angle (TIA) than those without PJK (P < 0.01). Multivariate analysis showed that a greater preoperative TIA and extended fusion were associated with PJK. The Scoliosis Research Society 22-item questionnaire score did not significantly differ between the PJK and non-PJK groups.

Conclusions

The preoperative TIA could be a predictor of PJK. Among patients with Lenke 5C AIS, those with a TIA of > 71° are more likely to develop PJK. Additionally, extended fusion in patients with Lenke 5C may increase the risk of PJK.

Complications following surgical treatment of adolescent idiopathic scoliosis: a 10-year prospective follow-up study

BACKGROUND

Accurate reporting of long-term complications of surgical treatment of adolescent idiopathic scoliosis (AIS) is critical, but incomplete. This study aimed to report on the rate of complications following surgical treatment of AIS among patients with at least 10 years of follow-up.

METHODS

This was a retrospective review of prospectively collected data from a multicenter registry of patients who underwent surgical treatment for AIS with minimum 10-year follow-up. Previously published complications were defined as major if they resulted in reoperation, prolonged hospital stay/readmission, neurological deficits, or were considered life-threatening. Rates and causes of reoperations were also reviewed.

RESULTS

Two hundred and eighty-two patients were identified with mean age at surgery of 14.6 ± 2.1 years. Mean follow-up was 10.6 (range 9.5-14) years. Eighty-seven patients had anterior spinal fusion (ASF); 195 had posterior spinal fusion (PSF). The overall major complication rate was 9.9% (n = 28) in 27 patients. Among PSF patients, the complication rate was 9.7% (n = 19) in 18 patients. The complications were surgical site infection (37%), adding-on (26%), pulmonary (16%), neurologic (11%), instrumentation (5%), and gastrointestinal (5%). In ASF patients, the complication rate was 10.3% (n = 9) among nine patients. The complications were pulmonary (44%), pseudoarthrosis (22%), neurologic (11%), adding-on (11%), and gastrointestinal (11%). The reoperation rate was 6.0% (n = 17) among 17 patients. Although most of the complications presented within the first 2 years (60.7%), surgical site infection and adding-on were also seen late into the 10-year period.

CONCLUSION

This is the largest prospective study with at least a 10-year follow-up of complications following spinal fusion for AIS, the overall major complication rate was 9.9% with a reoperation rate of 6.0%. Complications presented throughout the 10-year period, making long-term follow-up very important for surveillance.

LEVEL OF EVIDENCE

Therapeutic II.

Distal adding-on after surgery in Lenke 5C adolescent idiopathic scoliosis: clinical and radiological outcomes

Background

To evaluate the incidence and risk factors of postoperative distal adding-on in patients with Lenke 5C adolescent idiopathic scoliosis (AIS). More accurate selection criteria for the lower instrumented vertebra (LIV) should be confirmed to prevent distal adding-on.

Methods

Forty-six patients with Lenke 5C AIS who underwent posterior fusion were enrolled in the study. Patients were allocated into adding-on and no adding-on groups. Demographic data, clinical data, and radiographic parameters were recorded and compared.

Results

Postoperative distal adding-on occurred in eight patients (17.4%) during follow-up. Demographic data, clinical data, and baseline radiographic parameters of the two groups were not significantly different. The postoperative thoracolumbar (TL) or lumbar (L) Cobb angle, LIV translation, and LIV + 1 translation were higher in the adding-on group than those in the no adding-on group, while the postoperative coronal imbalance of the adding-on group was lower than that of the no adding-on group. The level difference of last barely touched vertebra (LBTV) and last substantial touched vertebra (LSTV) with LIV were higher in the adding-on group than in the no adding-on group.

Conclusion

Postoperative TL/L curve, postoperative LIV translation, postoperative LIV + 1 translation, and postoperative coronal imbalance were determined as risk factors for postoperative distal adding-on in patients with Lenke 5C AIS. Moreover, LIV selection of LBTV-1 or LSTV-1 may cause a higher risk of postoperative distal adding-on.

Preoperative pelvic obliquity: possible relation to postoperative coronal decompensation in thoracolumbar/lumbar adolescent idiopathic scoliosis

OBJECTIVE

Pelvic obliquity is frequently observed in patients with adolescent idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curve. This study aimed to assess pelvic obliquity changes and their effects on clinical outcomes of posterior fusion surgery.

METHODS

Data in 80 patients (69 with type 5C and 11 with type 6C adolescent idiopathic scoliosis) who underwent posterior fusion surgery were retrospectively analyzed. Pelvic obliquity was defined as an absolute pelvic obliquity angle (POA) value of ≥ 3°. The patients were divided into groups according to preoperative pelvic obliquity. Moreover, patients with preoperative pelvic obliquity were divided based on POA change from preoperative values versus 2 years postoperatively. Patients were divided based on the presence of selective or nonselective TL/L fusion. Radiographic parameters and clinical outcomes were compared between these groups.

RESULTS

Among 80 patients, 41 (51%) showed preoperative pelvic obliquity, and its direction was upward to the right for all cases. Coronal decompensation 2 years postoperatively was significantly elevated in patients with preoperative pelvic obliquity (p < 0.05). Thirty-two patients (40%) displayed pelvic obliquity 2 years postoperatively. Among 41 patients with preoperative pelvic obliquity, 22 patients (54%) were in the group with a decrease in POA, and 19 were in the group with no decrease. The group with no decrease in POA showed significant TL/L curve progression throughout the postoperative follow-up period. The patients with nonselective fusion showed a significantly lower incidence of pelvic obliquity at 2 years postoperatively.

CONCLUSIONS

Postoperative coronal decompensation more frequently occurred in patients with preoperative pelvic obliquity than in those without pelvic obliquity preoperatively. In addition, postoperative pelvic obliquity changes may be related to residual lumbar curve behavior.

How to select the lowest instrumented vertebra in Lenke 5/6 adolescent idiopathic scoliosis patients with derotation technique

PURPOSE

To introduce and evaluate our lowest instrumented vertebra (LIV) selection criteria for Lenke type 5/6 adolescent idiopathic scoliosis (AIS) patients with de-rotation technique.

METHODS

There were 53 eligible Lenke 5/6 AIS patients with minimum 2-year follow-up enrolled in current study. The LIV selection criteria were: (1) the first vertebra touching the central sacral vertical line (CSVL) or the most cephalad vertebra which can return to stable zone under lateral bending position; (2) vertebral rotation no more than grade II by Nash-Moe rotation evaluation; (3) the lowest instrumented vertebra disc angle (LIVDA) could be reversed on lateral bending position. Demographic data, operation data and radiographic data were obtained and analyzed.

RESULTS

Both clinical evaluation and radiographic data showed satisfactory outcome. The thoracolumbar/lumbar curve was improved from 53.4 ± 11.0° preoperatively to 6.9 ± 2.6° at the final follow-up. Two patients (3.8%) with adding on and two patients (3.8%) with coronal decompensation were identified at the final follow-up. LIV translation, LIV tilt and LIV disc angle were gradually improved after operation. The preoperative LIV tilt was positively correlated with Cobb angle (p = 0.010) and AVT (p = 0.030) at the final follow-up, and preoperative LIVDA was positively correlated with Cobb angle (p = 0.033) at the final follow-up.

CONCLUSION

In Lenke 5/6 scoliosis, the current LIV selection criteria with de-rotation technique contribute to satisfactory correction rate of 87.1% and minimal alignment complications of 7.6%. LIV could be spontaneously and progressively improved after operation. Preoperative LIV tilt and LIVDA could predict postoperative correction and coronal balance.

Anterior versus posterior fusion surgery in idiopathic scoliosis: a comparison of health-related quality of life and radiographic outcomes in Lenke 5C curves - results from the Swedish spine registry

PURPOSE

To compare health-related quality of life and radiographic outcomes in patients treated with either anterior or posterior fusion surgery for Lenke 5C type idiopathic scoliosis.

METHODS

We used data from the Swedish spine registry and identified 59 patients with idiopathic scoliosis treated with fusion for Lenke 5C type curves; 27 patients underwent anterior surgery and 32 underwent posterior surgery. All patients had pre- and postoperative radiographic data and postoperative clinical data at a minimum of two years after surgery. Patient-reported outcomes measures included the Scoliosis Research Society (SRS)-22r, EuroQoL 5 dimensions 3 levels (EQ-5D-3L), EQ-visual analogue scale (VAS) and VAS for back pain. Radiographic assessment included measurement of the angle of the major curve, disc angulation below the lowest instrumented vertebra, curve flexibility, rate of curve correction, differences in sagittal parameters, number of fused vertebrae and length of fusion.

RESULTS

The mean age at surgery was 16 years in both groups. The mean follow-up time was 3.8 years. There were no significant differences in the SRS-22r score and EQ-5D-3L index at follow-up (all p ≥ 0.2). Postoperatively, both the anterior and posterior fusion group demonstrated a significant correction of the major curve (p ≤ 0.001) with no significant difference of the correction rate between the groups (p = 0.4). The posterior fusion group had shorter operative time (p < 0.001) and higher perioperative blood loss (p = 0.004) while the anterior group had lower number of fused vertebrae ( p< 0.001).

CONCLUSION

The type of surgical approach for Lenke 5C curves is not associated with differences in health-related quality of life, despite the lower number of fused vertebrae after anterior surgery.

LEVEL OF EVIDENCE

III.

Ponte osteotomies in a matched series of large AIS curves increase surgical risk without improving outcomes

PURPOSE

The routine use of Ponte osteotomies in adolescent idiopathic scoliosis (AIS) surgery is controversial with conflicting data for coronal plane correction and little analysis in the sagittal plane. The objective of this study was to analyze the efficacy of Ponte osteotomies in large curve AIS.

METHODS

A single institution, prospectively-collected series of consecutive AIS patients who had Ponte osteotomies (P cohort) was directly matched to patients with no Pontes (NP cohort) by age, gender, Lenke classification, surgeon, coronal, and sagittal Cobb angles. The radiographic review included adjusted values using a 3D-derived published formula for preoperative T5-T12 kyphosis. Patient-reported outcomes (PROs) were assessed with the SRS-30 and Spinal Appearance Questionnaire (SAQ).

RESULTS

There were 68 patients (34/cohort) with minimum 2-year follow-up with no differences between P and NP cohorts in age, preoperative coronal Cobb (74.5° vs 70.8°), flexibility index, measured or 3D-adjusted T5-T12 kyphosis. Rod material/diameter, fusion levels, blood loss, and operative time did not differ, but implant density was higher in the P group (1.53 vs 1.31, p < 0.001). The P group had 7.9% greater coronal Cobb correction (66.6% vs 58.7%, p < 0.003) without difference in final Cobb angles (24.7° vs. 29.1°, p = 0.052). There were no differences in measured or adjusted T5-T12 kyphosis in the sagittal plane. The P group had a 15% rate of critical intraoperative neuromonitoring changes versus 0% in the NP group (p = 0.053). At follow-up, there were no differences in scoliometer measurements or any domain of SRS-30 or SAQ scores.

CONCLUSION

In this first reported matched series of AIS patients, Ponte osteotomies provide small radiographic gains in the coronal plane with no improvement in the sagittal plane and no change in truncal rotation. There was a higher risk of critical intraoperative neuromonitoring changes, and no benefits in patient-reported outcomes. This calls into question the routine use of Ponte osteotomies in AIS, even for curves averaging 70 degrees.

LEVEL OF EVIDENCE

II.

Should L3 be selected as the lowest instrumented vertebra in patients with Lenke type 5C adolescent idiopathic scoliosis whose lowest end vertebra is L4?

OBJECTIVE

L3 is most often selected as the lowest instrumented vertebra (LIV) to conserve mobile segments in fusion surgery; however, in cases with the lowest end vertebra (LEV) at L4, LIV selection as L3 could have a potential risk of correction loss and coronal decompensation. This study aimed to compare the clinical and radiographic outcomes depending on the LEV in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5C curves.

METHODS

Data from 49 AIS patients with Lenke type 5C curves who underwent selective thoracolumbar/lumbar (TL/L) fusion to L3 as the LIV were retrospectively analyzed. The patients were classified according to their LEVs into L3 and L4 groups. In the L4 group, subanalysis was performed according to the upper instrumented vertebra (UIV) level toward the upper end vertebra (UEV and 1 level above the UEV [UEV+1] subgroups). Radiographic parameters and clinical outcomes were compared between these groups.

RESULTS

Among 49 patients, 32 and 17 were in the L3 and L4 groups, respectively. The L4 group showed a lower TL/L curve correction rate and a higher subjacent disc angle postoperatively than the L3 group. Although no intergroup difference was observed in coronal balance (CB), the L4 group showed a significantly higher main thoracic (MT) and TL/L curve progression during the postoperative follow-up period than the L3 group. In the L4 group, the UEV+1 subgroup showed a higher absolute value of CB at 2 years than the UEV subgroup.

CONCLUSIONS

In Lenke type 5C AIS patients with posterior selective TL/L fusion to L3 as the LIV, patients with their LEVs at L4 showed postoperative MT and TL/L curve progression; however, no significant differences were observed in global alignment and clinical outcome.

Preoperative Thoracic Curve Magnitude and L4 End Vertebra Were Risk Factors for Subjacent Disc Wedging After Selective Thoracolumbar/Lumbar Fusion with L3 as the Lowest Instrumented Vertebra in Lenke Type 5 Curve Patients

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVE

This study aimed to investigate the incidence and risk factors of subjacent disc wedging (SDW) in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5 curve.

SUMMARY OF BACKGROUND DATA

SDW is frequently observed after surgery; however, data about its mechanism and relations with outcome are limited.

METHODS

Data of 59 patients with AIS with Lenke type 5 curves who underwent posterior spinal fusion to L3 as the lowest instrumented vertebra (LIV) were retrospectively analyzed. The subjacent disc angle (SDA) was defined as the angle between L3 (LIV) and L4. SDW was defined as the absolute value of SDA of 10° or higher 2 years postoperatively. The incidence of SDW was investigated between nonselective and selective thoracolumbar/lumbar (TL/L) fusion group. In the selective group, patients with and without SDW were compared.

RESULTS

Among 59 patients, 11 had nonselective and 48 had selective fusion. No patients in the nonselective group showed SDW versus 13 patients in the selective group (27%) showed SDW. In the selective group, patients with SDW showed significantly greater main thoracic curve, apical vertebral translation of the main thoracic curve, upper instrumented vertebra tilt, LIV tilt, and SDA 2 years postoperatively, whereas no differences were found in the coronal balance or clinical outcome. Multivariate analysis revealed preoperative T curve and SDA as predictors of SDW occurrence. T curve greater than 30° and SDA greater than 0° were calculated as cutoff values based on the receiver operating characteristic curve.

CONCLUSION

SDW is sometimes seen in Lenke type 5 patients with AIS who underwent selective TL/L fusion. SDW seemed to occur as a compensation mechanism for progressing deformity of unfused segments (thoracic curve and residual lumbar curve) to maintain coronal alignment. Preoperative T curve > 30° and SDA > 0° (lower-end vertebra as L4) were determined as risk factors for SDW occurrence.Level of Evidence: 3.

Risk factors for persistent coronal imbalance or revision surgery following L3 LIV selection in adolescent idiopathic scoliosis (AIS)

STUDY DESIGN

Retrospective case-control.

OBJECTIVE

To identify a cohort of patients with persistent coronal imbalance (CIB) or revision surgery 5 years following fusion to an L3 lowest-instrumented-vertebra (LIV) and determine factors that make an L3 LIV high-risk. In surgical planning for AIS, L3 is chosen over L4 whenever possible to maximize motion segments below the LIV. Though fusion to an L3 LIV is common, the rate of failure and its risk factors have not been described.

METHODS

In this analysis of prospectively-collected multi-center data of AIS patients who underwent posterior spinal fusion (PSF) to an L3 LIV, we identified patients with CIB at 5 years and/or those who required revision surgery attributable to LIV selection. Patients who were balanced at 5 years and did not require revision surgery served as controls. Pre-operative patient and radiographic variables were compared between cases and controls to identify risk factors for CIB/revision surgery.

RESULTS

We identified 646 patients with 2-year follow-up and 225 patients with 5-year follow-up, of which 11 were found to have CIB and/or revision surgery attributable to selecting L3 as the LIV. There were statistically significant differences between cases and controls with respect to several pre-operative factors, including BMI (24.5 in cases vs. 20.1 in controls; p = 0.01), Lenke curve type (81.8% Lenke 5/6 vs. 44.4%; p = 0.03), lumbar curve magnitude (56 vs. 45°; p < 0.01), TL/L apical vertebral translation (AVT) (6.2 vs. 4.1 cm; p < 0.01), L3 angulation (30° vs. 22°; p < 0.01), L3 translation (4.3 vs. 2.9 cm; p < 0.01), thoracic rib hump (7° vs. 12°; p = 0.02), lumbar rib hump (16° vs. 10°; p < 0.01), and thoracolumbar (T10-L2) kyphosis (10.5° vs. 2°; p = 0.006). Multivariate logistic regression showed that pre-operative BMI, TL/L AVT, L3 angulation, L3 translation, lumbar rib hump, and thoracolumbar kyphosis were independent predictors of CIB/revision surgery.

CONCLUSIONS

An L3 LIV is frequently successful at 5 years post-operatively. Consider an L4 LIV when: pre-operative BMI ≥ 28, L3 angulation ≥ 25°, L3 translation ≥ 4 cm, TL/L AVT ≥ 6 cm, or the lumbar curve is large (≥ 55°) and rotated (≥ 10°).

LEVEL OF EVIDENCE

Level III.

Selection of Fusion Level for Adolescent Idiopathic Scoliosis Surgery : Selective Fusion versus Postoperative Decompensation

Adolescent idiopathic scoliosis (AIS), which is associated with an extensive range of clinical and radiological presentations, is the one of the most challenging spinal disorders. The goals of surgery are to correct the deformity in 3 dimensions and to preserve motion segments while avoiding complications. Despite the ongoing evolution of classification systems and algorithms for the surgical treatment of AIS, there has been considerable debate regarding the selection of an appropriate fusion level in AIS. In addition, there is no consensus regarding the exact description, relationship, and risk factors of coronal decompensation following selective fusion. In this review, we summarize the current concepts of selection of the fusion level for AIS and review the available information about postoperative coronal decompensation.

Clinical outcomes of selective fusion for the thoracolumbar-lumbar curve in patients with Lenke type 6C adolescent idiopathic scoliosis: a preliminary study

Limited evidence is available in the literature regarding the fate of the unfused structural thoracic curve following selective thoracolumbar-lumbar curve fusion (SLF) in Lenke 6C adolescent idiopathic scoliosis (AIS) patients. Therefore, we compared the outcomes of SLF between Lenke 6C and 5C AIS patients. We retrospectively reviewed 31 patients Lenke 5C (n = 18) and Lenke 6C (n = 13) AIS patients who underwent SLF at a single institution. Multiple radiological parameters were measured using whole-spine radiographs taken before and after surgery and at the last follow-up visit. SRS-22 at the final follow-up was obtained for clinical assessment. A total of 31 patients with a mean age of 14.6 years at operation who were followed for a mean of 6.4 years were included in this study. The Cobb angle of the unfused thoracic curve was spontaneously corrected immediately following SLF and increased slightly but not significantly at the final follow-up in both groups (Lenke 5C: pre 33.0°, post 14.4°, final 19.4°, Lenke 6C: pre 46.1°, post 31.7°, final 34.2°). At every time point, the thoracic Cobb angle was significantly larger in the Lenke 6C. SRS-22 score at the final follow-up, including the self-image domain, did not differ between the two groups. In this study, SLF for Lenke 6C AIS achieved a significant spontaneous correction of the unfused thoracic curve and yielded a comparable SRS-22 result at the final follow-up to that of Lenke 5C. Our findings suggest that SLF is a viable treatment option for Lenke 6C AIS.

What determines immediate postoperative coronal balance and delayed global coronal balance after anterior spinal fusion for Lenke 5C curves?

PURPOSE

To determine the factors associated with 6-week postoperative global coronal balance and delayed global coronal balance at 2-year follow-up after anterior spinal fusion for Lenke 5C curves.

METHODS

A total of 124 consecutive Lenke 5C curves with minimum 2-year follow-up was studied. Radiographic parameters were studied preoperatively, 6 weeks postoperatively, and 2 years postoperatively. Coronal balance was measured by C7-CSVL and trunk shift < 20 mm. The study outcomes were patients with early coronal balance and those who had immediate imbalance but developed delayed balance. Multivariate regression analyses of associated factors were performed with cutoffs determined by receiver operating characteristic curve.

RESULTS

31.5% patients attained global coronal balance immediate postoperatively and 89.4% of the early imbalance cases showed spontaneous coronal balance at 2-year follow-up. Increased preoperative UIV tilt (OR 1.093; p = 0.026; 95% CI: 1.011-1.182) and reduced immediate postoperative RSH difference (OR 0.963; p = 0.015; 95% CI: 0.935-0.993) were associated with immediate postoperative balance. For those with immediate imbalance, larger preoperative major Cobb angle (OR 1.226; p = 0.047; 95% CI: 1.003-1.499), less preoperative C7-CSVL (OR 0.829; p = 0.016; 95% CI: 0.712-0.966), and less immediate postoperative LIV tilt (OR 0.728; p = 0.013; 95% CI: 0.567-0.934) were associated with 2-year coronal balance. There was significant improvement in function (p = 0.006), self-image (p = 0.039) and total score domains (p = 0.014) in immediate imbalance to 2-year balance and imbalance groups.

CONCLUSION

Successful balance is achieved with a parallel fusion mass when performing anterior spinal fusion for Lenke 5C curves. Patients should be reassured that most attain eventual coronal balance despite the early imbalance. Level of evidence Therapeutic III.

How to select the lowest instrumented vertebra in Lenke type 5 adolescent idiopathic scoliosis patients?

BACKGROUND CONTEXT

The lowest instrumented vertebra (LIV) determination in Lenke type 5 Adolescent Idiopathic Scoliosis (AIS) requires a thorough understanding and prediction of the correction force on the LIV from coronal, sagittal, and axial plane. Although many LIV selection criteria have been reported, none of them comprehensively evaluated the multidimensional characteristics of the LIV till now.

PURPOSE

To develop and evaluate our LIV selection criteria in Lenke type 5 AIS patients using pedicle screw system via posterior approach.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

All consecutive patients with Lenke 5 curves who were treated with one-stage selective lumbar fusion using complete pedicle screw system in our center from January 2006 to December 2017, with minimum 2-year follow-up.

OUTCOME MEASURES

Age, gender and Risser grade, fused levels, operating time, intraoperative blood loss, complications, and Scoliosis Research Society (SRS)-22 questionnaires outcome were recorded. Coronal, sagittal, and axial parameters were measured from plain radiographs.

METHODS

A total of 138 consecutive patients with Lenke 5 curves treated with selective lumbar fusion were retrospectively analyzed, with minimum 2-year follow-up. Our LIV selection criteria include: (1) the most cephalad vertebrae touched by central sacrum vertical line (CSVL); (2) Nash-Moe rotation being equal or less than grade I on the standing AP radiograph; (3) CSVL cross between the two pedicles of LIV on concave bending film; (4) not at the apex of kyphosis. Radiographic data, operative data, perioperative complications and SRS-22 outcomes were collected and analyzed.

RESULTS

The mean follow-up period was 50.9±24.7 months. The thoracolumbar/lumbar curve was corrected from 46.9°±8.9° before surgery to 5.5°±2.6° at the final follow-up. The C7-CSVL was 19.7±6.2 mm before surgery and 5.2±3.4 mm at the final follow-up. The LIV translation was corrected from 22.3 ±5.4 mm before surgery to 4.8 ± 2.6 mm at the final follow-up, with the correction rate of 78.4%. The LIV tilt was corrected from 21.6 ± 4.4° before surgery to 2.6 ± 2.3° at the final follow up, with the correction rate of 87.9%. Our LIV saved 0.3 level than SRS-last barely touching vertebra, 0.6 level than SRS-last substantially touching vertebra, 0.9 level than neutral vertebra, and 1.4 level than stable vertebra.

CONCLUSION

The present study indicates using our LIV criteria, our study achieved the correction rate of thoracolumbar/lumbar curve as 88.9%, with the rate of adding on or coronal imbalance as 8.7% (12/138). The criteria may provide important guidance for preoperative decision-making in Lenke 5 AIS patients, and more multicenter prospective studies with larger samples are needed to further validate the findings of this study.

Three-dimensional analysis of the sagittal profile in surgically treated Lenke 5 curves in adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective.

OBJECTIVES

To determine how the pre- and postoperative three-dimensional (3D) sagittal profiles of Lenke 5 curves in idiopathic scoliosis patients compare to unaffected controls. Prior research evaluating the sagittal plane of Lenke 5 (thoracolumbar/lumbar) curves in 2D suggests that the major curve is hypolordotic.

METHODS

Patients with Lenke 5 curves treated with thoracolumbar/lumbar posterior fusion who had biplanar radiography (with 3D reconstruction) preoperatively (Pre) and 2+ years postoperatively (PO2Y) were included. A cohort of similarly aged controls (C) without spinal pathology was identified. The following 3D sagittal measurements were compared both pre- and postoperatively to controls: T1-T10, T10-L3, L3-S1, and pelvic incidence (PI). Kyphosis is designated by positive values, and lordosis by negative values.

RESULTS

Nineteen Lenke 5 patients and 125 controls were included. Preoperatively, Lenke 5 patients were hypokyphotic relative to controls from T1 to T10 (30° ± 13° vs. 42° ± 9°, p < 0.001) and hyperlordotic from T10 to L3 (- 26° ± 15° vs. - 13° ± 12°, p < 0.001). Lenke 5 spines were less lordotic from L3 to S1 (- 41° ± 9° vs. - 47° ± 7°, p = 0.004). PI was similar between groups (Lenke 5 Pre: 48° ± 13°, C: 46° ± 10°, p = 0.49). Postoperatively, the area of principal deformity (T10-L3) remained hyperlordotic (PO2Y: - 23° ± 10° vs. C: - 13° ± 12°, p < 0.001). The proximal and distal uninstrumented segments demonstrated spontaneous sagittal correction, becoming similar to controls: T1-T10 (PO2Y: 41° ± 12° vs. C: 42° ± 9°, p = 0.421) and L3-S1 (PO2Y: - 48° ± 9° vs. C: - 47° ± 7°, p = 0.56).

CONCLUSION

When measured in 3D, Lenke 5 curves were more lordotic than controls in the periapical region of the major coronal curve. Posterior correction improved sagittal alignment, including spontaneous sagittal correction of the unfused segments. However, ~ 10° of hyperlordosis persisted in the instrumented/fused T12-L3 segment. Intraoperative correction strategies should take this preoperative increase in 3D sagittal deformity into account during rod contouring as well as compression/distraction to restore more normal sagittal alignment.

LEVEL OF EVIDENCE

III.

Excessive correction impacts postoperative shoulder imbalance in lenke type 5C adolescent idiopathic scoliosis

BACKGROUND

Postoperative shoulder imbalance (PSI) has a negative impact on the surgical outcomes of patients with adolescent idiopathic scoliosis. This study aimed to evaluate the risk factors of PSI in patients with Lenke type 5C curves.

METHODS

This study included 100 patients who underwent posterior correction surgery using pedicle screw constructs for Lenke type 5C curves. The mean age of the patients at surgery was 15.5 ± 2.3 years, and the mean follow-up period was 36.6 ± 15.0 months. The subjects were classified into the following two groups: PSI and non-PSI. Radiographic parameters, including the preoperative and 2-year postoperative coronal and sagittal profiles, were compared between the two groups.

RESULT

PSI was found in eight patients (8.0%). The preoperative Cobb angles were 47.3° ± 8.7° and 48.0° ± 3.9° in the non-PSI and PSI groups, respectively. The correction rate in the PSI group was significantly higher than that in the non-PSI group (81.0% ± 17.7% vs. 67.7% ± 14.7%; p = 0.018). The preoperative T1 tilt angle in the PSI group was significantly larger than that in the non-PSI group (6.1° ± 3.3° vs. 3.1° ± 2.8°; p = 0.005). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.769 (p = 0.012, 95% confidence interval [CI], 0.556-0.982) and 0.763 (p = 0.014, 95% CI, 0.598-0.928) for the correction rate and preoperative T1 tilt, respectively. The cut-off value was 73% and 4° for the correction rate and preoperative T1, respectively.

CONCLUSION

PSI was found in 8.0% of Lenke type 5C curves. Excessive correction of the lumbar curve of >73% and preoperative T1 tilt of >4° can be risk factors for PSI in patients with Lenke type 5C curve.

Comparison of Pulmonary Function After Selective Anterior Versus Posterior Fusion for the Correction of Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

To compare the selective anterior spinal fusion (ASF) versus posterior spinal fusion (PSF) on postoperative pulmonary function testing (PFT) whether thoracotomy with separation of the diaphragm by anterior approach influences the PFT in thoracolumbar and lumbar adolescent idiopathic scoliosis (AIS).

METHODS

A multicenter series of AIS patients who underwent selective spinal fusion were retrospectively reviewed. Seventy-nine female patients were included (mean 15.8 years). There were 35 patients in the ASF group and 44 patients in the PSF group. Patient demographics, radiographic measurements, and PFT data from preoperative to 2-year follow-up were analyzed.

RESULTS

Preoperatively, there were no significant differences in PFTs between the groups. The ASF group patients were more likely to undergo shorter fusions (4.5 instrumented vertebral levels) than those in the PSF group (5.2 levels). At 2-year follow-up, forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) in ASF group were statistically lower than those in PSF group. When comparing preoperative and 2-year changes on each procedure, only %FVC showed significant difference in ASF while FVC, FEV₁, and %FEV₁ did not. Meanwhile, the ASF group showed a significant decrease in FVC at 6 and 12 months compared to preoperative values. In PSF group, there was a decrease at 6 months, returned to preoperative value at 1-year follow-up.

CONCLUSIONS

Pulmonary function after ASF and PSF was similar at 2 years; however, anterior group did not return to the baseline at 6 months and 1 year suggesting anterior approach may affect early postoperative pulmonary function.

Posterior Correction of Adolescent Idiopathic Scoliosis with High-Density Pedicle Screw-Only Constructs: 5 Years of Follow-Up

PURPOSE

This study aimed to analyze radiological outcomes in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior correction with high-density pedicle screw-only constructs. We hypothesized that high-density pedicle screw-only constructs in AIS would provide a high correction rate and would facilitate the maintenance of the correction or obviate the loss thereof.

MATERIALS AND METHODS

We retrospectively analyzed radiological outcomes over a minimum follow-up period of 5 years in patients with AIS who underwent posterior correction with high-density pedicle screw-only constructs. A total of 124 consecutive patients were included. Demographic data, including age, sex, operated fusion level, numbers of screw, Lenke curve type, Risser stage, and follow-up period were retrospectively collected from electronic medical records and radiological measurements including serial follow-up.

RESULTS

The average number of pedicle screws was 1.96/vertebra. The average curve correction was 48.3% for the proximal thoracic (PT) curve, 83.1% for the main thoracic (MT) curve, and 80.2% for the thoracolumbar/lumbar (TL/L) curve at final follow-up. Use of high-density pedicle screw-only constructs helped achieve excellent correction rates, with no significant loss of correction at final follow-up.

CONCLUSION

We obtained excellent correction rates of 48.3% for PT, 83.1% for MT, and 80.2% for TL/L curves using high-density pedicle screw-only constructs in AIS, with no significant loss of correction at final follow-up.

Midterm surgical outcomes of a short fusion strategy for adolescent idiopathic scoliosis with Lenke 5C curve

BACKGROUND CONTEXT

A previous study examined the short-term (2 years) outcomes of a short fusion strategy for Lenke type 5C curves. This strategy had a little less correction rate with no difference in coronal and sagittal balance and SRS-22 scores to those of a conventional strategy and was superior in operative time and intraoperative bleeding. However, its effectiveness in longer follow-up periods was unknown.

PURPOSE

To assess midterm surgical outcomes of a short fusion strategy for adolescent idiopathic scoliosis (AIS) with Lenke type 5C curve, involving posterior correction and fusion surgery (PSF) using pedicle-screw constructs.

STUDY DESIGN

Retrospective case series.

PATIENT SAMPLE

Twenty-nine patients who underwent PSF for AIS with Lenke type 5C curve with a minimum 5-year follow-up.

OUTCOME MEASURES

Radiographic parameters and SRS-22.

METHODS

We compared radiographic parameters and clinical outcomes between patients with an upper instrumented vertebra (UIV) at the end vertebra (EV) (n=12) and those treated by short fusion (S), with a UIV one level caudal to the EV (n=17).

RESULTS

A preoperative mean Cobb angle of 51.9±13.8° was corrected to 11.7±7.7° in the EV group, and an angle of 46.0±6.6° was corrected to 9.3±5.2° in the S group. The correction was maintained in both groups at the final follow-up, and the mean correction loss was 2.8±6.8° in the EV and 6.5±6.5° in the S group (p=.143). The mean correction rate at the final follow-up was not significantly different between the EV (71.4±11.8%) and S (64.9±13.7%) groups (p=.199). A Cobb angle of a thoracic curve was significantly improved immediately after surgery and maintained during the follow-up period in the both groups. Coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, L4 tilt, UIV/LIV tilt, shoulder balance, and SRS-22 had no difference between the two groups.

CONCLUSIONS

There was no difference in radiographic parameters and SRS-22 between patients treated with a UIV at the UEV and patients treated using a short fusion strategy, in which the UIV was one level caudal to the UEV. The short fusion strategy can be one of the alternatives in PSF for Lenke type 5C curves, at least in 5-year time frame.

Comparison of Ponte Osteotomies and 3-Column Osteotomies in the Treatment of Congenital Spinal Deformity

BACKGROUND

Congenital spinal deformity (CSD) has traditionally been treated with 3-column osteotomies [hemivertebrectomy (HV) or vertebral column resection (VCR)] to address rigid deformities. Alternatively, multiple Ponte osteotomies (PO) may provide correction while minimizing risk. The purpose of this study was to compare safety and outcomes of patients undergoing surgical treatment for CSD with these 3 procedures.

METHODS

Retrospective review of CSD patients treated with posterior spinal fusion between 1996 to 2013. Patients treated with multiple Ponte osteotomies (PO group) were compared with those managed with 3-column osteotomies (HV/VCR group). Patients with previous instrumentation, isolated cervical deformity, growing spine instrumentation, or <2 year follow-up were excluded. Deformity angular ratio (DAR) was calculated as curve magnitude divided by number of levels of the deformity.

RESULTS

There were 49 patients [17 PO, 32 HV/VCR (26 HV, 6 VCR)]. For the PO group, mean age was 14 years, and they had an average of 4 ponte osteotomies and 11 levels fused. Mean total DAR was 25 and mean number of congenital anomalies was 1.8 in the PO group. The HV/VCR group had a mean age of 7 years and 5 levels fused. Mean total DAR was 28 and mean number of congenital anomalies was 2.1 in the HV/VCR group. Patients had a mean of 54.1% correction of coronal deformity in the PO group and 54.4% in the HV/VCR group (P=0.78). Signal changes were observed less frequently with PO (1/17) and HV (1/26) than with VCR (4/6), P=0.001. Revision rates were 17.6% (3/17) in the PO group and 37.5% (12/32) in the HV/VCR group (P=0.35).

CONCLUSIONS

Patients with CSD and a mean total DAR of 25 treated with multiple PO and long fusions had correction comparable with the HV/VCR group. Patients treated with VCR had the highest incidence of signal changes and postoperative neurologic deficits.

LEVEL OF EVIDENCE

Level III.

Upper instrumented vertebra to the right of the lowest instrumented vertebra as a predictor of an increase in the main thoracic curve after selective posterior fusion for the thoracolumbar/lumbar curve in Lenke type 5C adolescent idiopathic scoliosis: multicenter study on the relationship between fusion area and surgical outcome

OBJECTIVE

Unfused main thoracic (MT) curvatures occasionally increase after selective thoracolumbar/lumbar (TL/L) fusion. This study sought to identify the predictors of an unacceptable increase in MT curve (UIMT) after selective posterior fusion (SPF) of the TL/L curve in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS).

METHODS

Forty-eight consecutive patients (44 females and 4 males, mean age 15.7 ± 2.5 years, range 13-24 years) with Lenke type 5C AIS who underwent SPF of the TL/L curve were analyzed. The novel "Shinshu line" (S-line) was defined as a line connecting the centers of the concave-side pedicles of the upper instrumented vertebra (UIV) and lowest instrumented vertebra (LIV) on preoperative radiographs. The authors established an S-line tilt to the right as S-line positive (S-line+, i.e., the UIV being to the right of the LIV) and compared S-line+ and S-line- groups for thoracic apical vertebral translation (T-AVT) and MT Cobb angle preoperatively, early postoperatively, and at final follow-up. The predictors for T-AVT > 20 mm at final follow-up were evaluated as well. T-AVT > 20 mm was defined as a UIMT.

RESULTS

Among the 48 consecutively treated patients, 26 were S-line+ and 22 were S-line-. At preoperative, early postoperative, and final follow-up a minimum of 2 years later, the mean T-AVT was 12.8 mm (range -9.3 to 32.8 mm), 19.6 mm (range -13.0 to 41.0 mm), and 22.8 mm (range -1.9 to 68.7 mm) in the S-line+ group, and 10.8 mm (range -5.1 to 27.3 mm), 16.2 mm (range -11.7 to 42.1 mm), and 11.0 mm (range -6.3 to 26.9 mm) in the S-line- group, respectively. T-AVT in S-line+ patients was significantly larger than that in S-line- patients at the final follow-up. Multivariate analysis revealed S-line+ (odds ratio [OR] 23.8, p = 0.003) and preoperative MT Cobb angle (OR 7.9, p = 0.001) to be predictors of a UIMT.

CONCLUSIONS

S-line+ was defined as the UIV being to the right of the LIV. T-AVT in the S-line+ group was significantly larger than in the S-line- group at the final follow-up. S-line+ status and larger preoperative MT Cobb angle were independent predictors of a UIMT after SPF for the TL/L curve in patients with Lenke type 5C AIS. Surgeons should consider changing the UIV and/or LIV in patients exhibiting S-line+ during preoperative planning to avoid a possible increase in MT curve and revision surgery.

Are inferior facetectomies adequate and suitable for surgical treatment of adolescent idiopathic scoliosis?

STUDY DESIGN

Retrospective review.

BACKGROUND

Inferior facetectomies, with the utilization of segmental pedicle screw constructs for corrective fixation, can provide adequate flexibility and post less risk of neural tissue and blood loss. We analyzed outcomes of surgical treatment for adolescent idiopathic scoliosis (AIS) using inferior facetectomies and segmental pedicle screw constructs. We hypothesized that adequate main curve correction and suitable surgical outcomes would be observed using this technique.

METHODS

We reviewed 38 AIS patients who underwent inferior facetectomies and segmental pedicle screw constructs by 2 surgeons at a single institution between May 2014 and December 2016. Coronal and sagittal radiographic measurements were evaluated over 1-year follow-up by 2 trained observers not associated with the surgeries. Surgical details, complications, and hospital length of stay (LOS) were also recorded.

RESULTS

Mean fusion levels were 11.0 ± 1.7. The mean Cobb angle of main AIS curves improved from 48.6± 10.1 degree preoperatively to 11.8± 6.2 degree postoperatively and 12.4± 6.2 degree at 1-year follow-up, which percentage correction was 75.9% and 74.6%, respectively. The mean thoracic kyphosis (T5-12) angle was 20.7± 11.6 degree preoperatively, 17.4± 8.0 degree postoperatively, and 16.8± 8.4 degree at 1-year follow-up. The mean surgical time, estimated blood loss, and LOS were 232.4 ± 35.7 minutes, 475.0 ± 169.6 mL, and 3.5 ± 1.3 days. Twelve patients received blood transfusion. There were no neurological or wound complications.

CONCLUSIONS

This case series demonstrated adequate correction of main AIS curves, acceptable thoracic kyphosis and blood loss, and short surgical time and LOS in AIS patients treated with inferior facetectomies and segmental pedicle screw constructs, potentially indicating that inferior facetectomies are adequate and suitable for AIS surgery when segmental pedicle screw constructs are utilized.

One-Stage Posterior Multiple-Level Asymmetrical Ponte Osteotomies Versus Single-Level Posterior Vertebral Column Resection for Severe and Rigid Adult Idiopathic Scoliosis: A Minimum 2-Year Follow-up Comparative Study

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

To compare the efficacy and safety of one-stage posterior multiple-level asymmetrical Ponte osteotomies (MAPOs) and single-level posterior vertebral column resection (VCR) for severe and rigid adult idiopathic scoliosis (ADIS).

SUMMARY OF BACKGROUND DATA

The surgical treatment of severe and rigid ADIS is a demanding and difficult challenge due to its complicated characteristics. Spine surgeons have often pursued advanced correction techniques such as VCR for such patients, which reported to present excellent correction outcomes. But this attractive procedure brought the greatest risk to both surgeons and patients.

METHODS

A total of 48 patients who underwent MAPO or VCR and fusion surgery with minimum 2-year follow-up between February 2009 and November 2015 were enrolled. Twenty-six patients were included in MAPO group and 12 patients in VCR group with an average age of 26.65 ± 8.40 and 27.92 ± 7.50 years, respectively. The average follow-up was 30.24 ± 10.55 months. The surgical details and complications were recorded. The radiological parameters and clinical outcome including Oswestry Disability Index and Scoliosis Research Society-22 questionnaire scores were collected and analyzed.

RESULTS

The main curve in MAPO and VCR group were corrected from an average of 98.52° ± 16.50° to 44.11° ± 17.72° and 108.91° ± 16.56° to 56.49° ± 18.82° with no significant difference. The postoperative coronal and sagittal parameters of the two groups were all improved and it showed no significant differences between the two groups. The mean operative time and blood loss of VCR group were significantly greater than those of MAPO group. All the clinical scores were significantly improved at final follow-up, with no significant difference. The incidence of complications in MAPO group was 3.85%, which was significantly lower than that of VCR group.

CONCLUSION

The surgical procedure of multiple asymmetrical Ponte osteotomy is a safe, easy-to-operate, and effective technique that can correct scoliosis and restore the sagittal alignment. It can gain similar correction outcome to VCR, offering the advantages of reduced operation time, blood loss, and greatly reduced the complication.

LEVEL OF EVIDENCE

3.

Sagittal Alignment Profile Following Selective Thoracolumbar/Lumbar Fusion in Patients With Lenke Type 5C Adolescent Idiopathic Scoliosis

STUDY DESIGN

A retrospective case series.

OBJECTIVE

This study aimed to report the sagittal outcome measures in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) undergoing thoracolumbar/lumbar (TL/L) fusion surgery.

SUMMARY OF BACKGROUND DATA

Previous studies have demonstrated coronal correction of Lenke type 5C AIS by selective TL/L fusion surgery. However, little is known about the sagittal influence of selective TL/L curve correction in Lenke type 5C AIS.

METHODS

Thirty-nine patients with Lenke type 5C AIS underwent selective posterior TL/L curves fusion (mean age, 15.9 ± 2.1 yrs). Preoperative and postoperative radiographic and clinical parameters were analyzed at a minimum 2-year follow-up period. Radiographic parameters were compared between patients with Lenke sagittal modifier normal (Group N) to those with Lenke sagittal modifier minus (Group M).

RESULTS

The main TL/L Cobb angle was 46.3° ± 7.7° preoperatively and 20.7° ± 5.3° (P < 0.0001) at 2-year follow-up. Also, thoracic kyphosis (TK) (T1-12) angle was 29.0° ± 11.3° preoperatively and 36.4° ± 10.3° at follow-up (P < 0.001), and TK (T5-12) angle was 18.1° ± 10.2° preoperatively and 25.9° ± 8.9° at follow-up (P < 0.001). The cervical lordosis (CL) was 9.6° ± 11.6° preoperatively and 6.1° ± 10.9° at follow-up (P = 0.037). Compared with the Lenke sagittal modifier groups, preoperative TK (T1-12), TK (T5-12), thoracolumbar kyphosis (TLK), and CL were significantly different from both the groups; and after the surgery, no significant differences in these parameters were observed between the two groups.

CONCLUSION

After the selective TL/L posterior fusion surgery in patients with Lenke type 5C AIS, the sagittal alignment profile, including TK, TLK, C7 sagittal vertical axis, T1 slope, and CL, was significantly changed. With regard to the sagittal aspect, selective TL/L surgery was more likely to affect Group M than Group N.

LEVEL OF EVIDENCE

4.

Long-Term Follow-Up of Anterior Spinal Fusion for Thoracolumbar/Lumbar Curves in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective patient series analysis with update of long-term data.

OBJECTIVE

To define the long-term prognosis of the thoracolumbar/lumbar correction after selective anterior spinal fusion (ASF) in adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The ASF is a well-described procedure for the treatment of AIS. The correction reliability over time, the consequences in adjacent spinal levels and patient's quality of life are fundamental for the characterization of AIS treatment.

METHODS

One hundred seven patients were submitted to single-rod ASF for thoracolumbar/lumbar (ThL/L) AIS between 1993 and 2016 in a single-surgeon experience. Seventy five were available for final follow-up evaluation 9 years ±4 (2-23) after surgery. A clinical and sequential radiographic evaluations were performed.

RESULTS

The mean age at surgery was 16 years ± 2.33 (14-20) and 94 (87%) were females. The mean final follow-up of the 75 patients available was 9 years ± 4 (2-23). Sixty-five patients had a Lenke type 5C curve and 10 had a type 6C curve. The mean values of the Scoliosis Research Society 22 (SRS-22) questionnaire in Lenke 5C was 92 ± 9 (71-109) and in Lenke 6C 90.3 ± 9 (75-107). In Lenke 5C group, the mean preoperative ThL Cobb angle was 38.4° ± 9.3 (21-60) and the postoperative was 5.9° ± 4.5 (0-18; P < 0.001) being similar at the final follow-up (P > 0.05). In Lenke 6C group, the mean preoperative ThL Cobb angle was 58.6° ± 13.9 (40-90) and the postoperative ThL Cobb was 22.6° ± 14.5 (5-48, P < 0.001) being similar at the final follow-up (P > 0.05). The mean preoperative Thoracic (Th) Cobb angle was 39° ± 7.6 (30-50), the postoperative was 30.6° ± 10.1 (14-49, P < 0.008) and in the final follow-up was 29.3° ± 10.7 (11-48, P < 0.011).

CONCLUSION

ASF is a safe procedure in the treatment of ThL/L with good long-term results and high rates of satisfaction among patients with AIS Lenke type 5C. The partial correction was frequent in Lenke type 6C despite the absence of progression in the non-instrumented curves.

LEVEL OF EVIDENCE

4.

Surgical Treatment of Lenke Type 5 Adolescent Idiopathic Scoliosis: A Systematic Review

STUDY DESIGN

A systematic review.

OBJECTIVE

To systemically review the previous literature regarding surgical treatment of Lenke type 5 adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The Lenke classification was published in 2001 as the classification of AIS. Since then, numerous articles have been published reporting the outcomes of surgical treatment of Lenke type 5 AIS.

METHODS

The electronic databases PubMed, EMBASE, and Web of Science were queried up to Aug 2018 for articles regarding surgical treatment of Lenke type 5 AIS. Surgical variables, radiographic assessments, and clinical outcomes of surgical treatment of Lenke type 5 AIS were summarized.

RESULTS

Fifty studies met the inclusion criteria. The average fused levels, % correction of thoracolumbar/lumbar curve at final follow-up, and % correction of thoracic curve at final follow-up for anterior and posterior procedures were reported to be 3.6-5.3 and 4.3-7.8 levels, 53-86 and 55-94% and 17-52 and 19-67%, respectively. Average coronal balance was imbalanced (≥20 mm) at preoperation in 22/43 reporting study groups and balanced (<20 mm) at final follow-up in all 37 reporting study groups. Scoliosis Research Society Version 22 scores showed no difference between anterior and posterior procedures in most of the reporting studies (5/6).

CONCLUSION

Overall, the outcomes of surgical treatment of Lenke type 5 AIS are excellent. The thoracic curve was spontaneously corrected after surgery and coronal balance after surgery was better than before surgery. Both anterior and posterior procedures demonstrated satisfactory outcomes.

LEVEL OF EVIDENCE

4.

Posterior Multiple-Level Asymmetrical Ponte Osteotomies for Rigid Adult Idiopathic Scoliosis

OBJECTIVE

To evaluate the efficacy and safety of posterior multiple-level asymmetrical Ponte osteotomies for rigid adult idiopathic scoliosis.

METHODS

A retrospective study was conducted for adult patients with rigid idiopathic scoliosis (flexibility of main curve <25%) who underwent one-stage multiple-level asymmetrical Ponte osteotomies with a minimum of 2-year follow-up between February 2009 and November 2015. The demographic data and surgical issues were collected, and the improvement of clinical function scores and radiologic parameters were obtained after surgery and during the follow-up to assess deformity correction, spinal balance, and clinical outcome.

RESULTS

A total of 49 patients were included (10 male and 39 female) in this study, with an average age of 26.53 years old. The average follow-up was 28.37 ± 6.98 months. All the cases presented a significant improvement of the main curve and focal kyphosis from 85.62 ± 19.80° to 36.19 ± 16.74° and 53.98 ± 26.80° to 30.88 ± 18.69°, with a mean correction rate of 57.73% and 41.23%. The postoperative coronal and sagittal parameters were all significantly improved, except coronal balance. The mean operative time and blood loss were 267.86 ± 54.49 minutes and 838.78 ± 538.93 mL. All the clinical function scores of patients were significantly improved at the final follow-up. Only one patient had a complication related to surgical incision, with no neurologic complications occurring.

CONCLUSIONS

The surgical procedure of multiple-level asymmetrical Ponte osteotomy is a safe and effective technique, with reduced operation time, blood loss, and complications, and may offer an appropriate option to address the problems of rigid adult idiopathic scoliosis.

Ponte Osteotomies Increase the Risk of Neuromonitoring Alerts in Adolescent Idiopathic Scoliosis Correction Surgery

STUDY DESIGN

Observational cohort study of prospective database registry.

OBJECTIVE

To determine the incidence of neurological complications in AIS patients undergoing surgical treatment with PO.

SUMMARY OF BACKGROUND DATA

Despite the widespread use of Ponte Osteotomies (PO) in adolescent idiopathic scoliosis (AIS) correction, outcomes and complications in patients treated with this technique have not been well characterized.

METHODS

A multicenter prospective registry of patients undergoing surgical correction of AIS was queried at 2-year follow-up for patient demographics, surgical data, deformity characteristics, and peri-operative complications. A neurological complication was defined as perioperative nerve root or spinal cord injury as identified by the surgeon. Patients were divided into those who underwent peri-apical PO and those without, and further stratified by Lenke curve classification into 3 groups (I-types 1 and 2, II-types 3, 4, 6, and III-type 5). Patients with- and without neurological complications were compared with respect to baseline demographics, surgical variables, curve types, fusion construct types (screws vs. hybrid), curve magnitude (coronal and sagittal Cobb), apical vertebral translation, and coronal-deformity angular ratios (C-DAR).

RESULTS

Of 2210 patients included in the study, 1611 underwent PO. Peri-operative neurological complications occurred in 7 patients, with 6 in the PO group (0.37%) and 1 in non-PO group (0.17%) though this was not a statistically significant risk factor for peri-operative neurological injury (P = 0.45). Neuromonitoring alerts were recorded in 168 patients (7.6%: 9.3% PO group; 4.2% no-PO group (P < 0.001)). Multivariate logistic regression analysis found PO and curve magnitude to be independent risk factors for intraoperative neuromonitoring alerts (P < 0.01).

CONCLUSION

PO and curve magnitude were independent risk factors for intraoperative neuromonitoring alerts in surgical AIS correction. The effect of Ponte osteotomy on neurological complications remains unknown due to the low incidence of these complications.

LEVEL OF EVIDENCE

3.

Anterior Spinal Fusion and Posterior Spinal Fusion Both Effectively Treat Lenke Type 5 Curves in Adolescent Idiopathic Scoliosis: A Multicenter Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Retrospective comparison of radiographic and clinical outcomes between anterior spinal fusion (ASF) and posterior spinal fusion (PSF) in surgical treatment of Lenke 5 curves.

SUMMARY OF BACKGROUND DATA

ASF and PSF are used for treatment of Lenke 5 curves in patients with adolescent idiopathic scoliosis (AIS). Currently, no consensus exists for optimal surgical treatment of Lenke 5 curves.

METHODS

Patients with Lenke 5 curves treated with either ASF or PSF were prospectively enrolled in a multicenter database and then retrospectively reviewed. Demographic data, perioperative measures, radiographic data, and SRS-22R scores were collected and compared for statistical significance.

RESULTS

A total of 149 patients were included in the study; 51 underwent PSF and 98 underwent ASF. There was no difference in demographics between groups. The PSF group was fused one level longer than the ASF group (5.9 levels PSF, 4.6 levels ASF, p < .0001). The PSF group had shorter operative times (223 minutes PSF, 297 minutes ASF; p < .0001) and a higher proportion of patients who received a postoperative blood transfusion (45% vs. 5%, p < .0001). PSF patients had longer hospital stays (6.1d PSF vs. 5d ASF, p = .031). The ASF group had larger preoperative major curve (48.2° ASF, 44.2° PSF; p < .01). Coronal balance, thoracolumbar/lumbar Cobb angle, shoulder height, trunk shift, and overall sagittal balance were not different between groups at two-year follow-up. Curve correction at two-year follow-up was similar between groups (66% ASF vs. 62% PSF). There were no significant differences in clinical outcomes or complication rates between groups.

CONCLUSION

There is no difference in radiographic or clinical outcomes in patients treated with ASF or PSF for Lenke 5 curves. ASF may save a fusion level, but has longer operative time than PSF. Ultimately, the risks and benefits of each approach merit consideration by surgeon and patient.

LEVEL OF EVIDENCE

Level II.

Comparison of Extending Fusion to Thoracic Curve Versus Thoracolumbar/Lumbar Fusion in Posterior Fusion of Patients with Lenke 5C: Variation in Upper End Vertebrae Tilt Affected Coronal Balance

BACKGROUND

Extended fusion can be performed in patients with Lenke 5C adolescent idiopathic scoliosis (AIS) with a large and relatively rigid thoracic curve. Progression of the thoracic curve is related to coronal imbalance. We aimed to determine the correlation between the upper instrumented vertebra choice and coronal balance in patients with Lenke 5C AIS.

METHODS

A total of 61 patients with Lenke 5C AIS underwent posterior fusion from 2009 to 2015 in a single institution with ≥2 years of follow-up data available. The extended fusion group (n = 32) and thoracolumbar/lumbar (TL/L) fusion group (n = 29) were compared for the correction rates for the main TL/L and thoracic curves, coronal balance, upper end vertebra (UEV) tilt, and Scoliosis Research Society-22 questionnaire score.

RESULTS

Both groups had excellent correction of the main TL/L curve, and the extended fusion group had a significantly greater correction rate of the thoracic curve than the TL/L fusion group (70.2% vs. 57.3%). The incidence of coronal imbalance was similar in both groups. The spontaneous change in UEV tilt was associated with the change in coronal balance from the first to the final follow-up examination. In the TL/L fusion group, the increase in UEV tilt from the first to final follow-up visit resulted in improved coronal balance at the final follow-up examination. Both groups had similar Scoliosis Research Society-22 questionnaire scores at 2 years postoperatively.

CONCLUSIONS

In patients with Lenke 5C AIS, thoracic curve fusion results in better correction of the thoracic curve but no improvement in coronal balance. With TL/L fusion, a postoperative UEV tilt >5° leads to better coronal balance.

Selection of posterior spinal osteotomies for more effective periapical segmental vertebral derotation in adolescent idiopathic scoliosis-An in vivo comparative analysis between Ponte osteotomy and inferior facetectomy alone

BACKGROUND

Ponte osteotomy is a useful method in posterior spinal release. However, it is unclear whether Ponte osteotomy itself contributes to vertebral derotation in surgery for adolescent idiopathic scoliosis (AIS) patients compared to inferior facetectomy alone. This study aimed to assess the effect of Ponte osteotomy on the magnitude of periapical vertebral body rotation compared to inferior facetectomy alone. This study was a prospective collected data.

METHODS

The study included 63 patients with AIS (Thoracic curve type, 35; thoracolumbar/lumbar curve type, 27), who underwent surgery between August 2011 and January 2015. All AIS patients underwent posterior spinal fusion with uniplanar screws and Ponte osteotomies on three periapical intervertebral segments. We measured and analyzed the flexibility of periapical intervertebral rotation pre- and post-bilateral inferior facetectomy, and post-Ponte osteotomy with our device (three times). The difference in intervertebral rotation between pre- and post-Ponte osteotomy was analyzed.

RESULTS

The mean increase in angle was 5.6° for thoracic curves and 6.4° for thoracolumbar curves. The increase in angle for thoracolumbar curves was significantly larger than that for thoracic curves (P < 0.05). The more an apical region of the scoliosis was located at caudal side of spine, the more the flexibility due to Ponte osteotomy increased (P < 0.05). The significant differences of the increase in intervertebral flexibility between inferior facetectomies and Ponte osteotomies were recognized at middle thoracic and thoracolumbar regions (P < 0.005).

CONCLUSIONS

Our data suggest that Ponte osteotomy has a loosening effect on periapical scoliotic curvature compared to inferior facetectomy alone. Ponte osteotomy is likely to be associated with an increase in loosening of the middle thoracic and thoracolumbar regions.

Current concepts in the surgical management of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a complex 3D deformity of the spine. Its prevalence is between 2% and 3% in the general population, with almost 10% of patients requiring some form of treatment and up to 0.1% undergoing surgery. The cosmetic aspect of the deformity is the biggest concern to the patient and is often accompanied by psychosocial distress. In addition, severe curves can cause cardiopulmonary distress. With proven benefits from surgery, the aims of treatment are to improve the cosmetic and functional outcomes. Obtaining correction in the coronal plane is not the only important endpoint anymore. With better understanding of spinal biomechanics and the long-term effects of multiplanar imbalance, we now know that sagittal balance is equally, if not more, important. Better correction of deformities has also been facilitated by an improvement in the design of implants and a better understanding of metallurgy. Understanding the unique character of each deformity is important. In addition, using the most appropriate implant and applying all the principles of correction in a bespoke manner is important to achieve optimum correction.

In this article, we review the current concepts in AIS surgery.

Cite this article: Bone Joint J 2018;100-B:415–24.

Evolution of Surgery for Adolescent Idiopathic Scoliosis Over 20 Years: Have Outcomes Improved?

STUDY DESIGN

Retrospective review of a prospective adolescent idiopathic scoliosis (AIS) registry.

OBJECTIVE

To study the evolution of the operative approach, outcomes, and complication rates in AIS surgery over the past 20 years.

SUMMARY OF BACKGROUND DATA

Surgical techniques in AIS surgery have evolved considerably over the past 20 years. We study the trends in the operative management of AIS over this period and their impact on perioperative outcomes.

METHODS

A total of 1819 AIS patients (1995-2013) with 2-year F/U were studied. Operative approach, perioperative parameters, major complication rates, and SRS outcomes were assessed. Linear regression was used to assess the trend of changes over 5-year quartiles.

RESULTS

Mean age at surgery was 14.6 ± 2.1 years, 80.2% were females, and this remained consistent throughout. Operative time, EBL/level, and LOS decreased over the 20 years (P < 0.0001). The use of antifibrinolytic (AF) increased from 6.7% to 68.8% in the past 10 years (P < 0.0001). Number of levels fused increased and LIV was more distal (in relation to stable vertebrae) over time in Lenke 1 and 2 curves (levels fused 7.97-9.94, P < 0.0001 and 9.8-11.0, P=0.0134, respectively). Anterior spinal fusion (ASF) in Lenke 1 curves decreased from 81% in the first quartile to 0% in the last (P = 0.0429). ASF for Lenke 5 curves evolved from 78% in the second quartile to 0 in the last. Thoracoplasty performance decreased from 76% to 20.3% (P = 0.1632). All screw constructs in PSF cases increased from 0% to 98.4% (P = 0.0095). Two-year major complication rates decreased over time (18.7%-5.1%; P = 0.0173). Increased improvement in SRS scores were observed in pain, image, function, and total domains.

CONCLUSION

Evolution of surgical technique in AIS over the past 20 years has resulted in a cessation of anterior only surgery, increasing use of all screw constructs, less blood loss, greater use of AF, shorter operative times and LOS, lower major complications rates, and greater improvements in SRS scores.

LEVEL OF EVIDENCE

2.

A Detailed Comparative Analysis of Anterior Versus Posterior Approach to Lenke 5C Curves

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To prospectively compare radiographic, perioperative, and functional outcomes between anterior spinal instrumentation and fusion (ASIF) and posterior spinal instrumentation and fusion (PSIF) in Lenke 5C curves.

SUMMARY OF BACKGROUND DATA

Historically, ASIF has been the treatment of choice for treatment of thoracolumbar adolescent idiopathic scoliosis. More recently, PSIF has gained popularity for its ease, versatility, and amount of correction achieved. Current literature lacks a prospective comparative analysis between these two approaches to better aid treating surgeons in decision making when treating Lenke 5C curves.

METHODS

A prospective, longitudinal multicenter adolescent idiopathic scoliosis database was used to identify 161 consecutive patients with Lenke 5C curves treated by ASIF with a dual rod system, or PSIF with a pedicle screw-rod construct. Pre- and 2-year postoperative radiographic data, Scoliosis Research Society outcome scores, and perioperative comparisons were made between the two approaches.

RESULTS

A total of 69 patients were treated with ASIF and 92 patients with PSIF. Curve extent, magnitude, stable, and end vertebrae distribution before surgery were similar between the two groups. At 2-year follow-up, there were no significant differences in percentage correction of the main curve (ASIF: 59.1%, PSIF: 59.6%), C7 decompensation (ASIF: -0.6 ± 1.2, PSIF: -0.3 ± 1.4 cm), length of hospital stay (ASIF: 5.6 days, PSIF: 5.7 days), postoperative day conversion to oral pain medication (ASIF: 3.2 days, PSIF: 3.2 days), and SRS outcome scores (P = 0.560) between the two groups. The number of levels fused was significantly lower in ASIF group (ASIF: 4.7, PSIF: 6.3; P < 0.001), but PSIF resulted in significantly less disc angulation below lowest instrumented vertebrae (ASIF: 3.4°, PSIF: 1.7°; P = 0.011), greater lumbar lordosis (P < 0.001), and greater % correction of lumbar prominence (P = 0.017).

CONCLUSION

The amount of correction achieved was similar between ASIF and PSIF. ASIF resulted in shorter fusions (average 1.6 levels) compared with PSIF. This was at the expense of increased disc angulation below the lowest instrumented vertebrae, less lumbar lordosis, and a lower % correction of the lumbar prominence than PSIF.

LEVEL OF EVIDENCE

2.

Prognostic Role of Rib Hump in Overlying Thoracic Curve Correction Above Selective Fusion for Lenke 5 Idiopathic Adolescent Scoliosis

STUDY DESIGN

Prospective study.

OBJECTIVE

To assess whether rib hump is a prognostic factor of final thoracic Cobb angle.

SUMMARY OF BACKGROUND DATA

Correction of thoracolumbar/lumbar curve, preoperative thoracic curves angle, thoracic curves angle on bending, the thoracolumbar-lumbar angle/thoracic curves angle ratio, thoracic kyphosis, and growth stage influences spontaneous correction of uninstrumented thoracic curves angle above selective fusion for Lenke 5 Adolescent Idiopathic Scoliosis. Indeed, preoperative rib hump has never been expressly evaluated as a prognostic factor of final thoracic curves angle.

METHODS

In total, 50 patients with Lenke 5 Adolescent Idiopathic Scoliosis, selectively instrumented with posterior construct were included. Two patients were lost to follow-up and 48 had follow-up ≥2 years. Demographic data, preoperative thoracic rib hump (measured in millimeter in trunk anteflexion), and radiologic spinal parameters were recorded preoperatively and at last consultation. T test was used to compare mean values, linear and logistic regressions to assess predictability of final thoracic curve angle.

RESULTS

Main thoracolumbar-lumbar curve angle decreased from 47 degrees (range, 36-72 degrees) to 12 degrees at the final consultation (range, 1-28 degrees). Thoracic curves angle decreased from 26 degrees (range, 2-40 degrees) preoperatively to 16 degrees (range, 2-41 degrees) at the final consultation (P=0.001) (correction=37%). Preoperative rib hump was present in 10 patients. Final thoracic Cobb angle was 27 degrees (8-41 degrees) in patients with rib hump and 14 degrees (0-32 degrees) in patients without rib hump (P<0.001).Multiregression highlighted thoracic curves angle on bending (P=0.001), preoperative thoracic curves angle (P=0.011) and rib hump (P=0.012) as prognostic factors of higher final thoracic curves angle.

CONCLUSION

Rib hump significantly influenced final thoracic curves angle.

LEVEL OF EVIDENCE

Level III-prospective study.

Lowest Instrumented Vertebrae Selection for Posterior Fusion of Lenke 5C Adolescent Idiopathic Scoliosis: Can We Stop the Fusion One Level Proximal to Lower-end Vertebra?

BACKGROUND

The most appropriate fusion levels remains challenging, especially in Lenke type 5 curves. In Lenke 5 adolescent idiopathic scoliosis (AIS) generally fusion includes the lower end vertebra (LEV). This study determines whether it is appropriate to fuse mild to moderate Lenke 5 curves to LEV-1, if possible.

MATERIALS AND METHODS

Forty-two patients with mild to moderate Lenke 5 AIS that underwent posterior fusion were retrospectively evaluated. The preoperative goal was to stop the instrumentation at LEV-1 in all patients if possible. However, the final decision was made intraoperatively according to the alignment of the disc below lowest instrumented vertebra (LIV). In 19 patients, this goal was achieved and LIV was LEV-1, whereas 23 patients were fused to LEV. Hence, two groups occurred and they were compared in terms of coronal, sagittal, and LIV related parameters at 1 year and 3 years postoperatively. Surgical times were also noted. Clinical outcomes were assessed using scoliosis research society (SRS-22) and Short Form-36 questionnaires.

RESULTS

Two groups were well matched according to preoperative values. Postoperative radiographic results were also similar, except LIV disc angle and LIV translation, which were significantly higher in LEV-1 group at 1 and 3 years followup (P < 0.05). Surgical times were significantly longer in LEV group (P = 0.036). No significant correction loss was observed between 1 and 3 years followup. There were no significant differences regarding postoperative clinical outcomes except the activity domain of SRS-22, which was significantly higher in LEV-1 group, but the significance was weak (P = 0.045).

CONCLUSIONS

Fusion to LEV-1was associated with the higher amount of LIV disc angle and LIV translation, which did not cause coronal and sagittal imbalance and decreased the quality of life scores. Hence, if intraoperatively a level disc below LIV can be achieved, fusion to LEV-1 may be an option in mild to moderate Lenke 5 curves, to save one more mobile segment.

Flexibility assessment of the unfused thoracic segments above the "potential upper instrumented vertebrae" using the supine side bending radiographs in Lenke 5 and 6 curves for adolescent idiopathic scoliosis patients

BACKGROUND CONTEXT

Selection of upper instrumented vertebra for Lenke 5 and 6 curves remains debatable, and several authors have described different selection strategies.

OBJECTIVE

This study analyzed the flexibility of the unfused thoracic segments above the "potential upper instrumented vertebrae (UIV)" (T1-T12) and its compensatory ability in Lenke 5 and 6 curves using supine side bending (SSB) radiographs.

STUDY DESIGN

A retrospective study was used.

PATIENT SAMPLE

This study comprised 100 patients.

OUTCOME MEASURES

The ability of the unfused thoracic segments above the potential UIV, that is, T1-T12, to compensate in Lenke 5 and 6 curves was determined. We also analyzed postoperative radiological outcome of this cohort of patients with a minimum follow-up of 12 months.

METHODS

Right and left SSB were obtained. Right side bending (RSB) and left side bending (LSB) angles were measured from T1 to T12. Compensatory ability of thoracic segments was defined as the ability to return to neutral (center sacral vertical line [CSVL]) with the assumption of maximal correction of lumbar curve with a horizontal UIV. The Lenke 5 curves were classified as follows: (1) Lenke 5-ve (mobile): main thoracic Cobb angle <15° and (2) Lenke 5+ve (stiff): main thoracic Cobb angle 15.0°-24.9°. This study was self-funded with no conflict of interest.

RESULTS

There were 43 Lenke 5-ve, 31 Lenke 5+ve, and 26 Lenke 6 curves analyzed. For Lenke 5-ve, >70% of thoracic segments were able to compensate when UIV were at T1-T8 and T12 and >50% at T9-T11. For Lenke 5+ve, >70% at T1-T6 and T12, 61.3% at T7, 38.7% at T8, 3.2% at T9, 6.5% at T10, and 22.6% at T11 were able to compensate. For Lenke 6 curve, >70% at T1-T6, 69.2% at T7, 19.2% at T8, 7.7% at T9, 0% at T10, 3.8% at T11, and 34.6% at T12 were able to compensate. There was a significant difference between Lenke 5-ve versus Lenke 5+ve and Lenke 5-ve versus Lenke 6 from T8 to T11. There were no significance differences between Lenke 5+ve and Lenke 6 curves from T1 to T11.

CONCLUSIONS

The compensatory ability of the unfused thoracic segment of Lenke 5+ve curves was different from the Lenke 5-ve curves, and it demonstrated characteristics similar to the Lenke 6 curves.

Surgical correction of severe spinal deformities using a staged protocol of external and internal techniques

INTRODUCTION

There is high risk of neurologic complications in one-stage management of severe rigid spinal deformities in adolescents. Therefore, gradual spine stretching variants are applied. One of them is the use of external transpedicular fixation.

PURPOSE

Our aim was to retrospectively study the outcomes of gradual correction with an apparatus for external transpedicular fixation followed by internal fixation used for high-grade kyphoscoliosis in adolescents.

METHODS

Twenty five patients were reviewed (mean age, 15.1 ± 0.4 years). Correction was performed in two stages: 1) gradual controlled correction with the apparatus for external transpedicular fixation; and 2) internal posterior transpedicular fixation. Rigid deformities in eight patients required discapophysectomy. Clinical and radiographic study of the outcomes was conducted immediately after treatment and at a mean long-term period of 3.8 ± 0.4 years. Pain was evaluated using the visual analogue scale (VAS, 10 points). The Oswestry questionnaire (ODI scale) was used for functional assessment.

RESULTS

Deformity correction with the external apparatus was 64.2 ± 4.6% in the main curve and 60.7 ± 3.7% in the compensatory one. It was 72.8 ± 4.1% and 66.2 ± 5.3% immediately after treatment and 70.8 ± 4.6% and 64.3 ± 4.2% at long term, respectively. Pain relieved by 33.2 ± 4.2% (p < 0.05) immediately after treatment and by 55.6 ± 2.8% (p < 0.05) at long term. ODI reduced by 30.2 ± 1.7% (p < 0.05) immediately after treatment and by 37.2 ± 1.6% (p < 0.05) at long term.

CONCLUSION

The apparatus for external transpedicular fixation provides gradual controlled correction for high-grade kyphoscoliosis in adolescents. Transition to internal fixation preserves the correction achieved, and correction is maintained at long term.

Radiological factors affecting post-operative global coronal balance in Lenke 5 C scoliosis

Background

Lenke 5 C curves are frequently associated with clinically and radiological coronal imbalance. Appropriate selection of proximal and distal levels of fusion is essential to ensure good coronal balance (CB). We aimed to evaluate radiological factors associated with (I) global CB in the early post-operative period; (II) late decompensation of CB; and (III) favourable spontaneous correction of CB on long term follow up.

Methods

Twenty-three Lenke type 5C scoliosis cases treated with selective posterior lumbar instrumentation were retrospectively evaluated. Pre-operative, early post-operative and late post-operative (>2 years) whole length radiographs were analysed. Cobb's angle, lumbar lordosis, coronal imbalance, lower instrumented vertebra (LIV) tilt and translation and upper instrumented vertebra (UIV) tilt and translation were measured. The proximal and distal fusion levels were noted and correlated with post-operative CB.

Results

There were 21 females and 2 males with a mean follow up of 36 months. The mean pre-operative cobb angle was 55°±13.26°, which corrected to 14.7°±8.84° and was maintained on follow up. Eight patients had early post-operative coronal imbalance with spontaneous resolution seen in six cases on long term follow-up. At final follow-up, four cases had coronal imbalance (persistent imbalance since early post-operative period =2; late decompensation =2). In cases with early imbalance 5/8 cases had a pre-operative LIV tilt of ≥25°. All four patients with coronal imbalance at final follow-up had pre-operative LIV tilt ≥25°. Radiographic parameters which correlated with post-operative coronal imbalance were pre-operative LIV tilt (r=0.64, P=0.001), pre-operative LIV translation (r=0.696, P<0.001), pre-operative UIV translation (r=0.44, P=0.030), post-operative LIV tilt (r=0.804, P<0.001), and post-operative UIV tilt (r=0.62, P=0.001).

Conclusions

In Lenke 5C scoliosis, a pre-operative LIV tilt ≥25° significantly correlates with post-operative global coronal imbalance. Increasing UIV tilt may be a factor that accounts for improvement of CB in late follow-up period.

Management of Scoliosis in Patients With Loeys-Dietz Syndrome

BACKGROUND

Loeys-Dietz syndrome (LDS) is a genetic connective tissue disorder. We sought to determine the incidence of scoliosis in patients with LDS, characterize the spectrum of spinal deformity, determine the results of bracing and surgery, and define surgical complications.

METHODS

Patients were selected from our institution's database of 183 patients with LDS. Imaging measurements were performed for 141 patients whose records permitted spinal evaluation. Deformity changes and complications after intervention were recorded for patients who underwent bracing or surgery, and associations were tested using Student t tests (significance, P<0.05).

RESULTS

Eighty-eight of 141 (62%) patients with LDS had scoliosis, with main thoracic and thoracolumbar curves being most common. Fifteen patients were braced (mean age, 9±3 y) for a mean of 2.3 years. They had a mean postbracing curve progression of 12±21 degrees (5±9 deg./y). There were no significant differences in age, sex, curve type, or prebracing curve magnitude between successfully braced (n=4) and unsuccessfully braced (n=11) patients (P>0.05). Nine patients, (mean age, 12±3 y), underwent 24 surgical procedures (16 growing rod procedures, 8 fusions). Mean curve corrections were 61% for growing rods and 73% for fusions. Associated blood loss for these procedures was 400 mL and 1293 mL, respectively, and normalized blood loss for fusion was 2.34 mL/kg/level. Fifteen of 24 surgical procedures involved complications (63%), including cerebrospinal fluid leaks (n=7) and blood loss >20% of estimated total blood volume (n=11).

CONCLUSIONS

Scoliosis was present in 62% of our sample of LDS patients. Bracing did not halt curves in 11 of 15 patients, whose curves progressed >5 degrees or to >50 degrees by completion of bracing. At latest follow-up, 47% of the braced patients had undergone surgery after prior bracing attempts. The high blood loss associated with these operations is believed to be related to vascular fragility in patients with LDS.

LEVEL OF EVIDENCE

Level IV-retrospective cohort study.

Pain is the Greatest Preoperative Concern for Patients and Parents Before Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Prospective cross-sectional study.

OBJECTIVE

To evaluate patients' and parents' concerns so they can be addressed with appropriate preoperative counseling.

SUMMARY OF BACKGROUND DATA

Despite much research on outcomes for posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS), little is available about preoperative fears or concerns.

METHODS

Patients with AIS undergoing PSF, their parents, and surgeons were prospectively enrolled and asked to complete a survey on their fears and concerns about surgery at their preoperative appointment.

RESULTS

Forty-eight patients and parents completed surveys. Four attending pediatric spine surgeons participated and submitted 48 responses. Mean age of patients was 14.2 years. On a scale of 0 to 10, mean level of concern reported by parents (6.9) was higher than that reported by patients (4.6). Surgeons rated the procedure's complexity on a scale of 0 to 10 and reported a mean of 5.2. Neither patients' nor parents' level of concern correlated with the surgeons' assessment of the procedure's complexity level (R = 0.19 and 0.12, P = 0.20 and P = 0.42, respectively). Top three concerns for patients were pain (25%), ability to return to activities (21%), and neurologic injury (17%). Top three concerns for parents were pain (35%), neurologic injury (21%), and amount of correction (17%). Top three concerns for surgeons were postoperative shoulder balance (44%), neurologic injury (27%), and lowest instrumented vertebrae selection (27%). Patients reported the same concerns 23% of the time as parents, and 17% of the time as surgeons. Parents and surgeons reported the same concerns 21% of the time.

CONCLUSION

Pain was the greatest concern for both patients and parents but was rarely listed as a concern by surgeons. Parent and patient level of concern did not correlate to the surgeon's assessment of the procedure's complexity. Neurologic injury was a top concern for all groups, but otherwise there was little overlap between physician, patient, and parent concerns.

LEVEL OF EVIDENCE

3.