Selection Of Lowest Instrumented Vertebra Research Articles

The Optimal Lowest Instrumented Vertebra to Prevent the Distal Adding-On Phenomenon in Patients Undergoing Selective Thoracic Fusion for Adolescent Idiopathic Scoliosis with Lenke Type 1A and 1B Curves: Comparison of Nine Selection Criteria.

Background/Objectives: There is no solid consensus regarding which lowest instrumented vertebra (LIV) selection criterion is best to prevent distal adding-on (DA) after adolescent idiopathic scoliosis (AIS) surgery. This study aims to search out the LIV selection criteria in the literature and to compare the ability of each LIV selection criterion to prevent DA in patients with AIS. Methods: Patients who underwent thoracic fusion for AIS of Lenke type 1A or 1B were included in this study. Nine criteria for LIV selection were found in a literature review. For each patient, whether the postoperative actual location of LIV was met with the suggested locations of the LIV was assessed. The preventive ability of nine criteria against DA was evaluated using logistic regression analysis. The patients who met the LIV selection criteria but developed DA were investigated. Results: The study cohort consisted of 145 consecutive patients with a mean age of 14.8 years. The criteria of Suk (OR = 0.267), Parisini (OR = 0.230), Wang (OR = 0.289), and Qin (OR = 0.210) showed a significantly decreased risk of DA if the LIV selection criterion was chosen at each suggested landmark. As the additional levels were fused, there was no statistically significant benefit in further reducing the risk of DA. Among the patients who met each criterion, the incidence of DA was lower in criteria by Takahashi (5.9%), Qin (7.1%), and King (7.4%) than the others. Conclusions: Qin's criterion, using the substantially touching vertebra concept, has the highest preventive ability against DA development. Extending the instrumentation further distal to this suggested LIV criterion did not add further benefit.

Selection of posterior fixation segments for Lenke 5 adolescent idiopathic scoliosis

With the further understanding of the concept of three-dimensional correction by spinal surgeons, the progress of internal fixation instruments, de-rotation tools and the improvement of surgical techniques, the scientific formulation of surgical strategies for Lenke 5 adolescent idiopathic scoliosis has gradually become the focus of controversy. The formulation of preoperative surgical strategy not only directly affects the correction of deformity and balance reconstruction, but also is directly related to the activity function of spine and the quality of life of patients after operation. Therefore, this paper will discuss from three aspects: the method of surgical fixation, the surgical approach and the selection of fixed vertebrae. The author believes that Risser sign should be taken as an important consideration to judge the method of surgical fixation. The choice of surgical approach must refer to the operator's familiarity and experience with the approach, grasp the adaptive signs and consider the risks and benefits of the operation, and choose the appropriate surgical approach according to the needs of different patients. The choice of fixed vertebrae, choosing upper end vertebra (UEV) as upper instrumented vertebra (UIV), is safer than the more radical upper end vertebra-1 (UEV-1), and five factors need to be combined in the specific selection of lower instrumented vertebra (LIV).

Optimal lowest instrumented vertebra selection with consideration of coronal and sagittal planes to prevent distal junctional complications in patients with Lenke type 1A and 2A adolescent idiopathic scoliosis.

Postoperative distal adding-on and distal junctional kyphosis are major distal junctional complications after selective thoracic fusion in patients with adolescent idiopathic scoliosis (AIS). This study aimed to investigate the incidence of distal adding-on and distal junctional kyphosis and evaluate the validity of our selection criteria for the lowest instrumented vertebra (LIV) in patients with Lenke type 1A and 2A AIS. We retrospectively analyzed the data of patients with Lenke type 1A and 2A AIS, who underwent posterior fusion surgery. LIV selection included the followings: (1) stable vertebra on traction film, (2) disc space neutralization below the LIV on the side-bending film, and (3) lordotic disc below the LIV on the lateral film. Radiographic parameters and the revised 22-item Scoliosis Research Society Questionnaire (SRS-22r) were evaluated. The incidence of postoperative distal adding-on and distal junctional kyphosis was also investigated. Ninety patients (83 women and 7 men; 64 with type 1A and 26 with type 2A) were included. After the operation, each curve and the SRS-22r of self-image, mental health, and subtotal domains were significantly improved. Distal adding-on occurred in three patients (3.3%, one in type 1A and two in type 2A) at 2years postoperatively. No patients exhibited distal junctional kyphosis. Our LIV selection criteria could reduce the incidence of postoperative distal adding-on and distal junctional kyphosis in patients with Lenke type 1A and 2A AIS. Level IV.

Is It Necessary to Cross the Cervicothoracic Junction in Posterior Cervical Decompression and Fusion for Multilevel Degenerative Cervical Spine Disease? A Systematic Review and Meta-Analysis.

Posterior cervical decompression and fusion (PCF) is a common procedure for treating patients with multilevel degenerative cervical spine disease. The selection of lower instrumented vertebra (LIV) relative to the cervicothoracic junction (CTJ) remains controversial. This study aimed to compare the outcomes of PCF construct terminating at the lower cervical spine and crossing the CTJ. A comprehensive literature search was performed for relevant studies in the PubMed, EMBASE, Web of Science, and Cochrane Library database. Complications, rate of reoperation, surgical data, patient-reported outcomes (PROs), and radiographic outcomes were compared between PCF construct terminating at or above C7 (cervical group) and at or below T1 (thoracic group) in patients with multilevel degenerative cervical spine disease. A subgroup analysis based on surgical techniques and indications was performed. Fifteen retrospective cohort studies comprising 2071 patients (1163 in the cervical group and 908 in the thoracic group) were included. The cervical group was associated with a lower incidence of wound-related complications (RR, 0.58; 95% CI 0.36 to 0.92, p = 0.022; 831 patients in cervical group vs. 692 patients in thoracic group), a lower reoperation rate for wound-related complications (RR, 0.55; 95% CI 0.32 to 0.96, p = 0.034; 768 vs. 624 patients), and less neck pain at the final follow-up (WMD, -0.58; 95% CI -0.93 to -0.23, p = 0.001; 327 vs. 268 patients). However the cervical group also developed a higher incidence of overall adjacent segment disease (ASD, including distal ASD and proximal ASD) (RR, 1.87; 95% CI 1.27 to 2.76, p = 0.001; 1079 vs. 860 patients), distal ASD (RR, 2.18; 95% CI 1.36 to 3.51, p = 0.001; 642 vs. 555 patients), overall hardware failure (including hardware failure of LIV and hardware failure occurring at other instrumented vertebra) (RR, 1.48; 95% CI 1.02 to 2.15, p = 0.040; 614 vs. 451 patients), and hardware failure of LIV (RR, 1.89; 95% CI 1.21 to 2.95, p = 0.005; 380 vs. 339 patients). The operating time was reasonably shorter (WMD, -43.47; 95% CI -59.42 to -27.52, p < 0.001; 611 vs. 570 patients) and the estimated blood loss was lower (WMD, -143.77; 95% CI -185.90 to -101.63, p < 0.001; 721 vs. 740 patients) when the PCF construct did not cross the CTJ. PCF construct crossing the CTJ was associated with a lower incidence of ASD and hardware failure but a higher incidence of wound-related complications and a small increase in qualitative neck pain, without difference in neck disability on the NDI. Based on the subgroup analysis for surgical techniques and indications, prophylactic crossing of the CTJ should be considered for patients with concurrent instability, ossification, deformity, or a combination of anterior approach surgeries as well. However, long-term follow-up outcomes and patient selection-related factors such as bone quality, frailty, and nutrition status should be addressed in further studies.

A Hierarchical Approach to Realignment Strategies in Adult Cervical Deformity Surgery.

Retrospective cohort study. Construct an individualized cervical realignment strategy based on patient parameters at the presentation that results in superior 2-year health-related quality of life metrics and decreased rates of junctional failure and reoperation following adult cervical deformity surgery. Research has previously focused on adult cervical deformity realignment thresholds for maximizing clinical outcomes while minimizing complications. However, realignment strategies may differ based on patient presentation and clinical characteristics. We included adult cervical deformity patients with 2-year data. The optimal outcome was defined as meeting good clinical outcomes without distal junctional failure or reoperation. Radiographic parameters assessed included C2 Slope, C2-C7, McGregor's slope, TS-CL, cSVA, T1 slope, and preoperative lowest-instrumented vertebra (LIV) inclination angle. Conditional inference trees were used to establish thresholds for each parameter based on achieving the optimal outcome. Analysis of Covariance and multivariable logistic regression analysis, controlling for age, comorbidities, baseline deformity and disability, and surgical factors, assessed outcome rates for the hierarchical approach within each deformity group. One hundred twenty-seven patients were included. After correction, there was a significant difference in meeting the optimal outcome when correcting the C2 slope below 10 degrees (85% vs. 34%, P <0.001), along with lower rates of distal junctional failure (DJF) (7% vs. 42%, P <0.001). Next, after isolating patients below the C2 slope threshold, the selection of LIV with an inclination between 0 and 40 degrees demonstrated lower rates of distal junctional kyphosis and higher odds of meeting optimal outcome(OR: 4.2, P =0.011). The best third step was the correction of cSVA below 35mm. This hierarchical approach (11% of the cohort) led to significantly lower rates of DJF (0% vs. 15%, P <0.007), reoperation (8% vs. 28%, P <0.001), and higher rates of meeting optimal outcome (93% vs. 36%, P <0.001) when controlling for age, comorbidities, and baseline deformity and disability. Our results indicate that the correction of C2 slope should be prioritized during cervical deformity surgery, with the selection of a stable LIV and correction of cervical SVA below the idealized threshold. Among the numerous radiographic parameters considered during preoperative planning for cervical deformity correction, our determinations help surgeons prioritize those realignment strategies that maximize the health-related quality of life outcomes and minimize complications. Level-III.

The Role of Bending Films in the Lowest Instrumented Vertebra Selection in Adolescent Idiopathic Scoliosis Lenke Type 1A,B Based on Asymmetrical Disc Loading and Decompensation

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.

Is it Safe to Save Levels and Choose the Lowest Instrumented Vertebra as Touched Vertebra While Selectively Fusing Lenke 1/2 Curves? A Proportional Meta-Analysis of Existing Evidence.

Meta-analysis. To compare the clinical and radiological outcomes in patients with Adolescent Idiopathic scoliosis (AIS) treated by selective thoracic fusion (STF) with lowest instrumented vertebra (LIV) at touched vertebra (TV) vs stable vertebra (SV). The databases PubMed, Embase and Google Scholar were searched until November 2020.Studies which had Lenke type 1 curves and Lenke type 2 curves in adolescent population treated by STF and which reported pre- and post-operative curve characteristics including correction percentage and complications were included. Studies which did not report the LIV selection, curve correction percentages and whose full text could not be acquired were excluded. Eight studies were included for analysis of which seven were found to be retrospective studies (level III evidence) and one was prospective study (level II evidence) each. Overall proportional meta-analysis found no significant difference in correction rate, total srs-22 scores, and complication rates. The evaluation of SV group and TV group as LIV for selective thoracic fusions in AIS reveals a comparable outcome in terms of curve correction, patient satisfaction scores and complication rates. The TV can be chosen safely as the LIV especially in type A and B Lenke 1&2 curves, as it saves more motion segments when compared to SV.

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

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. 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. 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. 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.

Risk factors for the development of DJK in AIS patients undergoing posterior spinal instrumentation and fusion.

Typically, selection of lowest instrumented vertebra (LIV) in Adolescent Idiopathic Scoliosis (AIS) is based on the coronal radiograph; however, increasing evidence suggests that fusions proximal to the stable sagittal vertebrae (SSV) on the lateral radiograph can result in distal junctional kyphosis (DJK). The purpose of this study is to compare rates of DJK in patients with AIS that have a discordance between the Lowest Touched Vertebra (LTV) and the SSV and to identify risk factors for developing DJK. Patients with AIS Lenke type 1, 2 and 3 curves treated with a posterior spinal fusion were separated into two groups. Group 1 had SSV that was proximal to the LTV whereas group 2 had SSV that was distal to the LTV. Comparisons were made for patients that were fused to the SSV(a), LTV(b) or between(c). Distal junctional angle (DJA) > 5° and increasing kyphosis at the end of the fusion construct were evaluated as risk factors for DJK. The rate of DJK was 0.0% in group 1a, 1b, and 1c compared to 4.3%, 18.5% and 10.0% in groups 2a, 2b and 2c, respectively(p < 0.001). The rate of DJK was 22.9% when the distal junctional angle(DJA) > 5° versus 1.4% when the DJA < 5°(p < 0.001). There was a low risk for progression of DJK when the SSV was proximal to the LTV, however, those with SSV distal to the LTV represent a high-risk group. Importantly, the development of DJK occurred almost exclusively in patients with LIV at the thoracolumbar junction which demonstrates that surgeons need to be cautious when ending fusions at T11, T12, and L1 in patients at high risk for DJK. Furthermore, having a distal junctional angle 5° or greater increased the risk of developing DJK by roughly 16-fold. At a minimum of 5-year follow-up, the development of DJK did not appear to adversely impact SRS outcomes or revision rates.

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

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. 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. 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. 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.

56. The “Touched Vertebra (TV)” provides a reliable method for lowest instrumented vertebra (LIV) selection in adult idiopathic scoliosis (AdIS)

BACKGROUND CONTEXT LIV Selection in AdIS patients fused short of the sacrum is still debatable. Multiple radiographic methods have been devised to determine LIV, however, there is no universal standard. The TV rule for LIV determination has previously been described as providing acceptable LIV positioning on long-term follow-up in Adolescent Idiopathic Scoliosis (AIS) Lenke type-1 and -2 curves. We investigated whether the TV could be employed for guiding LIV selection in AdIS patients fused short of sacrum (LIV = L4 and above). PURPOSE The TV has been demonstrated as a reliable way to select the LIV in AIS. Here we sought to determine whether the TV rule is a reliable method for LIV selection in AdIS patients fused short of the sacrum. STUDY DESIGN/SETTING Single center/surgeon retrospective study. PATIENT SAMPLE Radiographic review of 52 patients with AdIS treated between July 2015 and December 2019. OUTCOME MEASURES CSVL-LIV distance determined on standing AP radiographs. METHODS AdIS patients treated by senior author between 2015 and 2019, with LIV L4 or above, and a minimum of 1-year radiographic follow-up (range: 1- 3 years) were included. The TV was determined on preoperative standing AP radiographs as the most cephalad lumbar vertebra “touched” by the center sacral vertical line (CSVL) and then compared to the LIV. Postoperative LIV position was evaluated in relation to the CSVL and the offset (CSVL-LIV distance) compared among patients fused cephalad-, caudad- and to the TV. RESULTS Fifty-two AdIS patients with ≥ 1 year of follow-up were available for review. Of these, 18 (35%) had fusion to the TV, 21 (40%) cephalad to the TV, and 13 (25%) caudad to the TV. Patients fused cephalad of the TV (TV≤-1) had larger CSVL-LIV distance (1.71±0.54 cm) on follow-up compared to those who had fusion to the TV (0.92±0.58cm) [p=0.05]. Patients who had fusion caudad to the TV (TV≥+1) had a shorter CSVL-LIV distance (0.7±0.58cm) compared to those fused to the TV, but this was not statistically significant. CONCLUSIONS Fusion to, or caudad to, the TV in AdIS results in significantly lower CSVL-LIV translation on radiographic follow-up compared to fusion cephalad to the TV. However, fusion caudad to the TV incurs fewer distal mobile segments, but with no significant benefit in decreasing CSVL-LIV translation, and thus fusion to the TV appears to be the best option in AdIS patients fused short of the sacrum. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. LIV Selection in AdIS patients fused short of the sacrum is still debatable. Multiple radiographic methods have been devised to determine LIV, however, there is no universal standard. The TV rule for LIV determination has previously been described as providing acceptable LIV positioning on long-term follow-up in Adolescent Idiopathic Scoliosis (AIS) Lenke type-1 and -2 curves. We investigated whether the TV could be employed for guiding LIV selection in AdIS patients fused short of sacrum (LIV = L4 and above). The TV has been demonstrated as a reliable way to select the LIV in AIS. Here we sought to determine whether the TV rule is a reliable method for LIV selection in AdIS patients fused short of the sacrum. Single center/surgeon retrospective study. Radiographic review of 52 patients with AdIS treated between July 2015 and December 2019. CSVL-LIV distance determined on standing AP radiographs. AdIS patients treated by senior author between 2015 and 2019, with LIV L4 or above, and a minimum of 1-year radiographic follow-up (range: 1- 3 years) were included. The TV was determined on preoperative standing AP radiographs as the most cephalad lumbar vertebra “touched” by the center sacral vertical line (CSVL) and then compared to the LIV. Postoperative LIV position was evaluated in relation to the CSVL and the offset (CSVL-LIV distance) compared among patients fused cephalad-, caudad- and to the TV. Fifty-two AdIS patients with ≥ 1 year of follow-up were available for review. Of these, 18 (35%) had fusion to the TV, 21 (40%) cephalad to the TV, and 13 (25%) caudad to the TV. Patients fused cephalad of the TV (TV≤-1) had larger CSVL-LIV distance (1.71±0.54 cm) on follow-up compared to those who had fusion to the TV (0.92±0.58cm) [p=0.05]. Patients who had fusion caudad to the TV (TV≥+1) had a shorter CSVL-LIV distance (0.7±0.58cm) compared to those fused to the TV, but this was not statistically significant. Fusion to, or caudad to, the TV in AdIS results in significantly lower CSVL-LIV translation on radiographic follow-up compared to fusion cephalad to the TV. However, fusion caudad to the TV incurs fewer distal mobile segments, but with no significant benefit in decreasing CSVL-LIV translation, and thus fusion to the TV appears to be the best option in AdIS patients fused short of the sacrum.

Defining risk factors for adding-on in Lenke 1 and 2 AR curves.

To identify curve/correction characteristics associated with adding-on at 2years after posterior spinal fusion (PSF) in Lenke 1/2 AR curves. A prospective multicenter registry was queried to identify patients with adolescent idiopathic scoliosis (AIS), Lenke 1/2 AR curves, who underwent PSF with a minimum of 2-year follow-up. Patient characteristics as well as pre- and post- operative radiographic variables were evaluated using Classification and Regression Tree (CART) analysis to determine which factors contribute to adding-on. 253 patients treated with PSF were assessed for adding-on, of which 50 met our adding-on criteria. Univariate analysis revealed adding-on was associated several factors including: post-operative thoracic and lumbar curve magnitude (p > 0.001), first erect (FE) end instrumented vertebra (EIV) angulation (p = 0.009) and EIV translation (p = 0.001), younger age (p = 0.027), Risser stage (p = 0.024), and a more proximal lowest instrumented vertebra (LIV) (p < 0.001). Multivariate CART analysis showed the chance of adding-on was more than 2 times greater (42 vs 16%) when the chosen LIV was translated more than 2.7cm from the CSVL. When the LIV was within 2.7cm, the post-op risk of adding-on was increased when the LIV was not perfectly leveled (> 0.5°). In Lenke 1 and 2 AR curves, pre-operative LIV translation appears to be an independent risk factor for adding-on; and in those with < 2.7cm of LIV translation, FE LIV angulation also seems to increase the risk of adding-on. These factors are relevant in determining appropriate LIV selection and aid in identifying patients at risk for developing adding-on.

Mid-long-term outcome and degeneration of the remaining unfused lumbar intervertebral disc in adolescent idiopathic scoliosis patients who had posterior spinal fusion surgery.

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.

Cervicothoracic Versus Proximal Thoracic Lower Instrumented Vertebra Have Comparable Radiographic and Clinical Outcomes in Adult Cervical Deformity.

Comparative cohort study. Factors that influence the lower instrumented vertebra (LIV) selection in adult cervical deformity (ACD) are less reported, and outcomes in the cervicothoracic junction (CTJ) and proximal thoracic (PT) spine are unclear. A prospective ACD database was analyzed using the following inclusion criteria: LIV between C7 and T5, upper instrumented vertebra at C2, and at least a 1-year follow-up. Patients were divided into CTJ (LIV C7-T2) and PT groups (LIV T3-T5) based on LIV levels. Demographics, operative details, radiographic parameters, and the health-related quality of life (HRQOL) scores were compared. Forty-six patients were included (mean age, 62 years), with 22 and 24 patients in the CTJ and PT groups, respectively. Demographics and surgical parameters were comparable between the groups. The PT group had a significantly higher preoperative C2-C7 sagittal vertical axis (cSVA) (46.9 mm vs 32.6 mm, P = 0.002) and T1 slope minus cervical lordosis (45.9° vs 36.0°, P = 0.042) than the CTJ group and was more likely treated with pedicle-subtraction osteotomy (33.3% vs 0%, P = 0.004). The PT group had a larger correction of cSVA (-7.7 vs 0.7 mm, P = 0.037) and reciprocal change of increased T4-T12 kyphosis (8.6° vs 0.0°, P = 0.001). Complications and reoperations were comparable. The HRQOL scores were not different preoperatively and at 1-year follow-up. The selection of PT LIV in cervical deformities was more common in patients with larger baseline deformities, who were more likely to undergo pedicle-subtraction osteotomy. Despite this, the complications and HRQOL outcomes were comparable at 1-year follow-up.

Including the stable sagittal vertebra in the fusion for adolescent idiopathic scoliosis reduces the risk of distal junctional kyphosis in Lenke 1-3 B and C curves.

The selection of lowest instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) is determined by coronal and sagittal plane indicators. Failure to properly select the LIV can lead to suboptimal outcomes and the need for revision surgery. A subset of patients have discordant coronal last touched vertebra (cLTV) and stable sagittal vertebra (SSV) which complicates the choice of LIV. The purpose of this study is to report the incidence of discordant cLTV and SSV when choosing LIV and investigate the association between length of fusion and patient-reported outcomes (PROs) and distal junctional kyphosis (DJK). This retrospective multicenter cohort study included AIS patients with discordant pre-operative cLTV and SSV. Patients fused only to include the proximal cLTV were compared to patients fused to include the distal SSV. Primary outcomes included DJK and PROs measured by SRS-22. Eight hundred and fifty-six patients were identified of which 114 (13.3%) had discordant SSV and cLTV. The DJK incidence was 7.7% and 45.5% in patients fused to include the SSV versus short of the SSV, respectively. Lenke Modifier type B and C patients with fusions short of the SSV had a 9.2 times increased risk of developing DJK at 2years compared to patients with fusions including the SSV (95% CI 2.8, 29.7; p < 0.001). However, patients with fusions short of the SSV and no evidence of DJK were 9.2 times more likely to have improvement in the SRS-22 pain domain compared to patients with fusions including the distal SSV (95% CI 1.1, 77.4; p = 0.042) CONCLUSION: Patients fused short of the SSV are at significant risk for the development of DJK at 2years post-operatively. However, patients with shorter fusions were more likely to have an improvement in their pain as measured by patient-reported outcomes than patients with longer fusions.

Selection of the Lowest Instrumented Vertebra and Relative Odds Ratio of Distal Adding-on for Lenke Type 1A and 2A Curves in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis.

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.

Lowest Instrumented Vertebra Selection in Posterior Cervical Fusion: Does Cervicothoracic Junction Lowest Instrumented Vertebra Predict Mechanical Failure?

Retrospective. The purpose of this study is to evaluate the effect of posterior cervical fusion lowest instrumented vertebra (PCF LIV) selection on incidence of mechanical failure, revision surgery, and patient-reported outcomes (PROs). Recent studies indicate that the LIV in PCF may contribute to the risk of mechanical failure. To date, the evidence available to guide spine surgeons in the selection of PCF LIV remains limited. All patients undergoing PCF at a single institution were prospectively entered into a spine registry which was retrospectively queried. Data collection included demographics, pathology, operative variables, construct LIV, outcomes of mechanical failure, revision surgery, and patient-reported disability, pain, and quality of life. Of 438 patients undergoing PCF from 2006 to 2019, 106 patients had an LIV of C7, T1, or T2, a minimum of 1-year follow-up, and met all study inclusion criteria. LIV cohorts were C7 LIV (36), T1 LIV (42), and T2 LIV (28). There were no between-group differences in patient demographics, operative variables, or postoperative follow-up across the three LIV cohorts. Mechanical failure rates for C7, T1, and T2 LIV were 30.6%, 23.8%, and 0%, respectively (P = 0.007). Revision rates for C7, T1, and T2 LIV were 25.0%, 11.9%, and 0%, respectively (P = 0.013). No difference was noted in average time to revision/failure between C7 (39.68 months) and T1 (29.85 months) LIV cohorts. No differences in baseline, 3-month, and 12-month postoperative PRO measures were noted in the C7 and T1 LIV cohort when compared to the T2 LIV cohort. The findings in this study indicate that PCF LIV selection may play a significant role in the development of mechanical complications and need for revision surgery. T2 LIV selection demonstrated a significantly lower rate of mechanical failure and revision surgery. Postoperative PROs up to 36 months are needed to evaluate effect of LIV selection on PROs.Level of Evidence: 3.

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

BACKGROUND CONTEXTThe 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. PURPOSETo develop and evaluate our LIV selection criteria in Lenke type 5 AIS patients using pedicle screw system via posterior approach. STUDY DESIGNA retrospective study. PATIENT SAMPLEAll 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 MEASURESAge, 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. METHODSA 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. RESULTSThe 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. CONCLUSIONThe 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.

How to Avoid Distal Adding-on Phenomenon for Rigid Curves in Major Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis? Identifying the Incidence of Distal Adding-on by Selection of Lowest Instrumented Vertebra

We sought to compare the radiologic outcomes for different distal fusion levels in a rigid curve with major thoracolumbar and lumbar (TL/L) adolescent idiopathic scoliosis (AIS) using rod derotation (RD) with direct vertebral rotation (DVR) after pedicle screw instrumentation (PSI). This study finally enrolled 28 patients who were diagnosed with AIS in rigid curve with major TL/L curves, treated by PSI with RD and DVR and with a minimum 2-year follow-up. Patients were divided into 2 groups, L3 and L4, on the basis of the distal fusion level at the lowest instrumented vertebra (LIV) of L3 or L4. There was no significant difference in TL/L curve, thoracic (minor), and compensatory (caudal) curves between the L3 and L4 groups either postoperatively (P= 0.162, 0.426, and 0.762, respectively) or at the last follow-up (P= 0.952, 0.620, and 0.562, respectively). The overall prevalence of unsatisfactory results was 42.9% (12/28 patients). The prevalence of unsatisfactory results was 61.1% (11/18) in the L3 group and 10% (1/10) in the L4 group, which was significantly different (P < 0.05). Unsatisfactory results occurred more often in the L3 group than in the L4 group, and unsatisfactory results had significant influence on progression of TL/L and distal compensatory curves. Such progression was closely correlated with deteriorating LIV disk angle in the L3 group. Therefore if the curve is rigid, LIV should be extended to L4 to avoid the adding-on phenomenon in the treatment of major TL/L AIS using RD with DVR after PSI.

Where to stop distally in Lenke modifier C AIS with lumbar curve more than 60°: L3 or L4?

ObjectiveSelecting lowest instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) with large lumbar curve can be difficult. Stopping the distal fusion at L3 could save more mobile lumbar segments but may increase the risk of decompensation. This study was designed to evaluate preoperative radiographic factors that were associated with the selection of either L3 or L4 as LIV in posteriorly treated AIS patients with large lumbar curve. Patients and methodsA total of 84 AIS patients with lumbar curve >60° were analyzed with a minimum of 2-year follow-up after posterior instrumentation with lumbar curves included in fusion. Patients were grouped according to the selection of LIV, either L3 or L4 group. All radiograph parameters were measured pre- and post-operatively including Cobb angle, lumbar flexibility, L3 translation and rotation on posteroanterior (PA) and side-bending (SB) film, etc. The SRS-22 score was used to assess clinical outcomes. Radiographic and clinical parameters were compared between the two groups. ResultsThere were 24 patients in L3 group and 60 patients in L4 group. At last follow-up, no difference was found in the clinical and radiographic parameters between the two groups. Preoperatively, the L3 group had lower L3 translation on PA view, L3 translation on concave SB film, L3 rotation on convex SB film, more L3/4 disc opening on convex SB film and larger lumbar flexibility. Multivariate regression found L3 translation on concave SB film was the single most important predictor of LIV selection. Specifically, L3 translation on concave SB film <10 mm was a potential threshold for selecting L3 as LIV. ConclusionsFor AIS patients with large lumbar curve, instrumentation can be reliably stopped at L3 if L3 translation on preoperative concave SB film was less than 10 mm, with the same radiographic and clinical outcomes as fusing to L4.