Strategies to Avoid Distal Junctional Pathology

Network meta-analysis. To determine lowest instrumented vertebra (LIV) in Lenke 5 & 6 Adolescent Idiopathic Scoliosis (AIS) patients. An extensive literature search was carried out aimed at identifying articles reporting outcomes in Lenke 5 and 6 AIS patients based on LIV selection. Apart from the study characteristics and demographic details, the extracted data included lumbar and thoracic curve correction, LIV angle (LIVA) correction, LIV disc (LIVD) angle correction, LIV translation correction (LIVT), OT time, blood loss, patient reported outcomes and complications. The extracted data was analyzed; forest plot and surface under the cumulative ranking curve (SUCRA) plots were generated to draw comparisons between lower end vertebra (LEV), LEV-1, and LEV+1 groups. Six studies were finally included for analysis. All six studies were case-control studies. Three studies compared LIV at LEV versus LEV+1, while the remaining three analyzed LIV at LEV versus LEV-1. The studies collectively analyzed 403 patients divided into LEV (225), LEV+1 (62), and LEV-1 (116) groups. No significant difference was found between the 3 groups with respect to the correction of cobb angle (lumbar, thoracic), LIVA, LIVT, ot time and blood loss. Significant difference was found only between LEV-1 versus LEV+1 with respect to LIVD angle correction. Adding on was seen in 1 pt in the LEV+1 group, 2 in LEV group, and 11 in LEV-1 group at 2 yr follow up in the included studies. This meta-analysis concluded that all three procedures are equally effective in radiological correction and patient-reported outcomes. However, selecting LEV-1 as LIV may lead to a higher risk of adding-on and distal disc wedging. While LEV is generally safe for most Lenke 5 and 6 curves, LEV+1 may be a more appropriate choice for cases with high preoperative LIVA, TL/L Cobb angle, LIVT, and rigid lumbar curves. II.

To investigate mid-long-term effects of the lowest instrumented vertebra (LIV) selection on adolescent idiopathic scoliosis (AIS) patients who had posterior spinal fusion (PSF) surgery. Forty-eight patients were recruited. Inclusion criteria were AIS patients who have had PSF surgery more than 10 years ago. Patients were divided into G1: LIV L3 or higher and G2: LIV L4 or lower. MRI evaluation was classified using Pfirrmann grades. Pfirrmann scores were average of Pfirrmann grades for all unfused discs below LIV. SRS-22r, SF-36, Oswestry Disability Index (ODI) and Modified Cincinnati Sports Activity Scale (MCSAS) were used. There were 19 patients in G1 and 29 patients in G2. Demographic parameters showed no significant differences. We found no significant differences in Pfirrmann grades or scores between G1 and G2. There was significant correlation between age and mean Pfirrmann scores (r = 0.546, p < 0.001), Pfirrmann grade for adjacent disc + 1 below LIV (r = 0.475, p = 0.001) and adjacent disc below LIV (r = 0.365, p = 0.011). G2 had significantly lower scores for SRS-22r pain (G1: 4.3 ± 0.5, G2: 4.0 ± 0.6, p = 0.044) and the SF-36 bodily pain (G1: 88.7 ± 12.3, G2: 77.8 ± 18.7, p = 0.018) domains. There were no significant differences in ODI and MCSAS between the two groups. Patients with fusion to L4 or lower had more significant back pain. However, both groups had similar physical function, self-image, satisfaction with treatment, mental health, and functional sports activity. We did not find any significant association between lumbar discs degeneration and the selection of LIV.

Traction X-ray under general anesthesia helps to save motion segment in treatment of Lenke type 3C and 6C curves

Patients with severe adolescent idiopathic scoliosis (AIS) require instrumented spinal fusion surgery. The range of instrumented vertebra is still questioned, especially the selection of the lowest instrumented vertebra (LIV). This single institution retrospective consecutive study is to provide real-world data on outcomes. The study aims to assess whether bending films can determine the LIV. The method of determination of the lower tilted vertebra (LTV) is presented. The selection of the LTV was identified on standing PA (LTVs) and on bending X-rays (LTVb). Group A is a reference group, with less flexible curves. Groups B and C contained patients with more flexible curves. Group B covered patients with instrumentation ending at the LTVs and group C with shorter instrumentation ending at LTVb. The disc angle below the LIV was monitored for postoperative decompensation. Sixty-eight subjects with AIS Lenke 1A and 1B types underwent selective fusion. The decompensation criteria of the unfused disc below the fusion were determined as a wedging disk of &gt;5° of the Cobb angle. The patients were monitored during the postoperative period with 5.8 years average followup (minimum of 2 years). The rate of decompensation was comparable in groups A and B (31% and 33%, respectively). In contrast, the rate of decompensation was doubled in group C (60%). Caudal fusion shortening in more flexible curves according to bending films is associated with the first free disc asymmetry, which leads to decompensation below the fusion. This method should be considered in addition to other LIV selection criteria.

L5 vs. pelvic fixation as the lowest instrumented vertebra in long-segment fusion for adult spinal deformity: a systematic review and meta-analysis.

Postoperative spinal alignment remodeling in Lenke 1C scoliosis treated with selective thoracic fusion

What's New in Pediatric Orthopaedic Surgery.

ObjectiveTo examine existing literature and pool the data to determine the relative odds ratio of “adding-on” (AO) based on various reported criteria for lower instrumented vertebra (LIV) selection in Lenke type 1A and 2A curves.MethodsUsing electronic databases, studies reporting on AO and LIV selection in Lenke type 1A and 2A curves were identified. Studies were excluded if they failed to meet the following criteria: ≥ 30 patients, Lenke type 1A or 2A curves, thoracic-only fusions, and inclusion of outcome differences in AO and non-AO groups. Review articles, letters, and case reports were excluded.ResultsSix studies were identified reporting on 732 patients with either Lenke type 1A or 2A curves treated with thoracic-only fusions. Five different landmarks were used for LIV selection in these studies including the stable vertebra (SV) -1, end vertebra (EV) +1, neutral vertebra (NV), touched vertebra (TV), and substantially touched vertebra (STV) versus nonsubstantially touched vertebra (nSTV) +1. The pooled odds ratios of AO for choosing LIV at levels above the afore landmarks (i.e., ending the construct “short”) versus at the landmarks were 2.59 (SV-1), 2.43 (EV+1), 3.05 (NV), 3.40 (TV), and 4.52 (STV/nSTV+1), all at 95% confidence interval.ConclusionFive landmarks shared a similar characteristic in that the incidence of AO was significantly higher if the LIV was proximal to the chosen landmark. In addition, choosing STV/(nSTV+1) as the LIV have the lowest absolute risk of AO and the greatest risk reduction. If additional levels were fused (i.e., LIV distal to the landmark), there was no statistically significant benefit in further reducing the risk of AO. Selection of the optimal LIV is a complex issue and spine surgeons must balance the risk of AO with the need for motion preservation in young patients.

To assess the benefits of using the touched vertebra (TV) rule in Lenke classification for thoracic curves of adolescent idiopathic scoliosis (AIS). A total of 141 AIS patients with thoracic curves determined by Suk classification were divided based on whether the lowest instrumented vertebra (LIV) matched the TV into groups of mTV (n = 84, LIV = TV), TV- (n = 21, LIV above TV), and TV+ (n = 36, LIV below TV) for 5-year follow-up. The radiological parameters were the central sacral vertical line (CSVL)-LIV distance, distal end vertebra rotation, coronal, and sagittal parameters. Complications included adding-on phenomenon, coronal imbalance, and distal junctional kyphosis. Adding-on phenomenon and coronal imbalance were significantly higher in the TV- group (P = 0.006) and TV + group (P = 0.006), respectively. The distal motion segments were significantly saved in the mTV group (P < 0.001). The CSVL-LIV distance was significantly improved in the mTV group compared to the others during the 5-year follow-up (P = 0.007). The 5-year follow-up CSVL-LIV distance correlated with LIV tilt angle (r = 0.442, P = 0.021) and coronal balance (r = 0.437, P = 0.023). Selecting the TV as LIV minimizes the loss of the distal mobile segment and reduces the complications in the thoracic curves of AIS, which produces a more stable LIV on the CSVL. Therefore, TV is an ideal landmark for determining the distal fusion level using the Lenke classification or Suk classification.

Retrospective study. To compare the long-term outcomes of correction surgery for Lenke 1A scoliosis patients among those with non-Substantially Touched Vertebra (nSTV), nSTV+1, or STV selected as lowest instrumented vertebra (LIV). Previous studies have documented good outcomes when last touching vertebra (LTV) was selected as LIV; however, it is sometimes confusing to determine the proper LTV when central sacral vertical line (CSVL) slightly touches the vertebra. A total of 104 patients were included in the study with a minimum of 2-year follow-up after selective posterior thoracic instrumentation. STV was defined as the LTV where CSVL was between the pedicles or touching the pedicle. nSTV was defined as the LTV where CSVL was touching the corner of the vertebra lateral to the pedicle border. Patients with nSTV, nSTV+1, or STV selected as LIV were assigned to three groups with clinical outcomes compared among them. Factors associated with the incidence of adding-on were analyzed. Distal adding-on was observed in 23 patients (22.1%). The incidence of distal adding-on was significantly higher in nSTV group than STV group or nSTV+1 group. Several risk factors significantly associated with adding-on were identified, including the distance between LIV and STV/nSTV+1, preoperative proximal thoracic curve and sagittal vertical axis, postoperative lumbar lordosis, apical translation, trunk shift, and radiographical shoulder height. Logistic regression analysis showed that the distance between LIV and STV/nSTV+1 (LIV-STV <0 or LIV-(nSTV+1) <0) was the only independent factor associated with the incidence of adding-on (odds ratio = 27.1, 95% confidence interval = 2.3-311.2, P = 0.002). Differentiating STV from nSTV properly can facilitate the determination of optimal LIV and decrease the incidence of distal adding-on. Selecting STV or nSTV+1 as LIV could yield a promising outcome for Lenke 1A scoliosis patients undergoing selective posterior thoracic fusion. 3.

P101. Distal junctional failure: a feared complication of adult spinal deformity surgery

The cervicothoracic junction (CTJ) is the site of transition in biomechanical, osseous, and alignment properties of the spine. The interface between the highly mobile, lordotic cervical spine and the rigid, kyphotic thoracic spine results increased the biomechanical stress experienced at this junction. The concentration of stress at this level has led to high rates of failure when instrumenting near or across the CTJ. The changes in osseous anatomy from the cervical spine to the thoracic spine present additional challenges in construct planning. For these reasons, a thorough understanding of the complexity of the cervicothoracic junction is necessary when operating near or across the CTJ. There are multiple options for cervical fixation, including lateral mass screws, pedicle screws, and laminar screws, each with its own advantages and risks. Instrumentation at C7 is controversial, and there is data supporting both its inclusion in constructs and no risk when this level is skipped. Thoracic pedicle screws are the preferred method of fixation in this region of the spine; however, the connection between cervical and thoracic screws can be challenging due to differences in alignment. Transitional rods and rod connectors mitigate some of the difficulties with this transition and have shown to be effective options. Recently, more investigation has looked into the failure of posterior cervical constructs which end at or near the CTJ. The trend in data has favored fixation to T1 or T2 rather than ending a construct at C7 due to the decreased rates of distal junction kyphosis. Although data on patient-reported outcomes with a length of constructs and the lowest instrumented vertebra is scarce, preliminary reports show no difference at this time. As posterior cervical instrumentation continues to increase in frequency, the CTJ will continue to be an area of difficulty in navigation and instrumentation. A thorough understanding of this region is necessary and continued research is needed to improve outcomes. Level V.

ObjectiveTo determine whether the last touched vertebra (LTV) on supine radiographs is suitable for the lower instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) correction surgery.MethodsIn total, 57 patients were included in the study following posterior instrumentation and fusion. The average follow-up period was 2.2 years. Patients were classified into 4 groups according to the relationship of the location of LIV, LTV, and the last substantially touched vertebra (LSTV) on upright radiographs and the LTV on supine radiographs. In group 1, the upright LTV and supine LTV were the same. Group 1 was subdivided into group 1A and group 1B according to whether the LTV and LSTV were different or the same, respectively. In group 2, the upright LTV was selected as the LIV, whereas in group 3, the supine LTV was selected as the LIV. The baseline characteristics and the preoperative and postoperative radiographic/clinical outcomes of the groups were analyzed.ResultsNo differences were found in the preoperative clinical and radiographic baseline characteristics of the 4 groups except the LIV-central sacral vertical line distance. The immediate, 6-month, 1-year, and 2-year postoperative outcomes were not significantly different among the 4 groups. One patient (4.3%) in group 1A experienced radiographic adding-on without clinical symptoms. No patients underwent revision surgery.ConclusionThe group in whom the LIV was selected as the LTV on supine x-rays showed similar postoperative radiographic and clinical results to other groups. The LTV on preoperative supine radiographs is acceptable as the LIV in AIS surgery to maximize motion segments.

Biomechanical effects of different instrumented segments and trunk shifts on distal adjacent segments after congenital scoliosis posterior hemivertebrectomy: Preliminary results of a single case

A radiographical follow-up and analysis. To investigate the postoperative curve change in Lenke 5C scoliosis, and to discuss how to select lowest instrumented vertebra (LIV). 5C curves are relatively rare in adolescent idiopathic scoliosis, and few studies have focused on this type of adolescent idiopathic scoliosis. Such questions as "How does the curve change over time in the postoperative period?" "Is LIV selection correlated with final correction and balance?" and "How should we select LIV for Lenke 5C curves?" need to be answered. We reviewed all the adolescent idiopathic scoliosis cases surgically treated in an institution from 2002 through 2008. Inclusion criteria were as follows: (1) patients with Lenke 5C curves who were treated with selective lumbar fusion; (2) minimum 2-year radiographical follow-up.All image data were available and all measurements were performed in picture archiving and communication systems. Standing posteroanterior and lateral digital radiographs were reviewed at 4 junctures: preoperative, immediate postoperative, 3 months, and 2 years postoperatively. Thirty patients met the inclusion criteria. The following results were observed: (1) From the perspectives of both Cobb angle and vertebral translation, significant correction was achieved; (2) The correction obtained by surgery was well retained in the postoperative period; (3) Although preoperative spinal imbalance was common in this group of patients, the majority eventually attained balance at 2 years; (4) LIV selection was significantly correlated with the 2-year correction and balance; (5) In the literature as well as in this study, the overall preoperative LIV-center sacral vertical line distance is 28 mm and the overall preoperative LIV tilt is 25°. In Lenke 5C scoliosis, preoperative spinal imbalance is common, although the majority of patients attain balance at 2 years. Significant correction loss is not common in the postoperative period. LIV selection significantly correlates with 2-year correction and balance. A translation of 28 mm and a tilt of 25° may be used as a general criterion for selecting LIV. 2.