Development Of Distal Junctional Kyphosis Research Articles

The Importance of Incorporating Proportional Alignment in Adult Cervical Deformity Corrections Relative to Regional and Global Alignment: Steps Toward Development of a Cervical-Specific Score.

The Global Alignment and Proportion(GAP) Score is widely used in adult spinal deformity surgery. However, it is not specific to the parameters used in adult cervical deformity(ACD). Create a cervicothoracic alignment and proportion(CAP) score in operative ACD patients. Retrospective single-center study. ACD patients with two-year(2Y) data were included. Parameters consisted of: relative McGregor's Slope[RMGS =(MGS*1.5)/0.9], relative cervical lordosis[RCL=CL - Thoracic Kyphosis(TK)], Cervical Lordosis Distribution Index(CLDI=C2-Apex*100/C2-T2), relative pelvic version(RPV=SS - PI*0.59+9), and a frailty factor(greater than 0.33). Cutoff points were chosen where the cross-tabulation of parameter subgroups reached maximal rate of meeting Optimal Outcome. Optimal outcome was defined as meeting Good Clinical Outcome(GCO) criteria without occurrence of distal junctional failure(DJF) or reoperation. CAP was scored between 0-13 and categorized accordingly: ≤3(Proportioned), 4-6(Moderately Disproportioned), >6(Severely Disproportioned). Multivariable logistic regression analysis determined the relationship between CAP categories, overall score and development of distal junctional kyphosis(DJK), DJF, reoperation, and Optimal Outcome by two years. 105 operative ACD patients were included. Assessment of three-month CAP score found a mean of 5.2/13 possible points. There were 22.7% of patients who were proportioned, 49.5% moderately disproportioned, and 27.8% severely disproportioned. DJK occurred in 34.5% and DJF in 8.7% DJF, 20.0% underwent reoperation, and 55.7% achieved Optimal Outcome. Patients severely disproportioned in CAP had higher odds of DJK (OR: 6.0,[2.1-17.7];P=0.001), DJF (OR: 9.7[1.8-51.8];P=0.008), reoperation(OR: 3.3,[1.9-10.6];P=0.011), and lower odds of meeting the optimal outcome(OR: 0.3,[0.1-0.7]; P=0.007) by two years, while Proportioned patients suffered zero occurrences of DJK or DJF. The regional alignment and proportion score is a method of analyzing the cervical spine relative to global alignment and demonstrates the importance of maintaining horizontal gaze, while also matching overall cervical and thoracolumbar alignment to limit complications and maximize clinical improvement.

14. Despite a multifactorial etiology, rates of distal junctional kyphosis after adult cervical deformity corrective surgery can be dramatically diminished by optimizing age-specific radiographic improvement

<h3>BACKGROUND CONTEXT</h3> Distal junctional kyphosis (DJK) is one of the most common complications in adult cervical deformity (ACD) correction. The utility of radiographic alignment alone in predicting and minimizing DJK occurrence warrants further study. <h3>PURPOSE</h3> To investigate the impact of postoperative radiographic alignment on development of DJK in ACD patients. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of a multicenter prospective ACD database. <h3>PATIENT SAMPLE</h3> A total of 450 ACD patients. <h3>OUTCOME MEASURES</h3> DJK after cervical deformity surgery. <h3>METHODS</h3> ACD patients (18 yrs) with complete baseline (BL) and two-year (2Y) radiographic data were included. DJF was defined as DJK greater than 15 or DJK with reop. Multivariable logistic regression (MVA) identified 3-month predictors of DJK. Conditional inference tree (CIT) machine learning analysis determined threshold cutoffs. Radiographic predictors were combined in a model to determine predictive value using area under the curve (AUC) methodology. "Match" refers to ideal age-adjusted alignment. <h3>RESULTS</h3> A total of 140 cervical deformity patients met inclusion criteria (61.3yrs, 67%F, BMI 29kg/m², CCI 0.96±1.3). Surgically, 51.3% had osteotomies, 47.1% had a posterior approach, 34.5% combined approach, 18.5% anterior approach, with an average 7.6± 3.8 levels fused and EBL of 824 mL. Overall, 33 patients (23.6%) developed DJK, and 11 patients (9%) developed DJF. MVA controlling for age, and baseline deformity, followed by CIT found 3M cSVA <3.7 cm (OR .2, 95% CI .06-.6), and TK T4-T12 <50 (OR .17, 95% CI .05-.5, both p <.05) were significant predictors of a lower likelihood of DJK. Receiver operator curve AUC using age, T1S match, TS-CL match, LL-TK match, cSVA <3.7 cm, and T4-T12 <50 predicted DJK with an AUC of .91 for DJK by 2 years, and .88 for DJF by 2 years. <h3>CONCLUSIONS</h3> These findings suggest postoperative radiographic alignment is strongly associated with distal junctional kyphosis. When utilizing age-adjusted realignment in addition to newly developed thresholds, a suggested postoperative cSVA target of 3.7 cm and thoracic kyphosis less than 50, it is possible to substantially reduce the occurrence of distal junctional kyphosis and distal junctional failure. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Risk of distal junctional kyphosis in scheuermann's kyphosis is decreased by selecting the LIV as two vertebrae distal to the first lordotic disc.

To determine whether (1) distal junctional kyphosis (DJK) is decreased by selecting the stable sagittal vertebra (SSV), versus the vertebra below the 1st lordotic disc (1stLD), as the lowest instrumented level (LIV); (2) DJK is decreased if the LIV is two versus one vertebrae distal to the 1stLD. A multi-institution prospective database was queried for SK patients who underwent posterior-only instrumentation and fusion with > 2year follow-up. DJK was defined as > 10° change in the distal junctional angle postoperative from the preoperative junctional angle. Statistical analysis was performed using ttest, chi-square test and logistic regression. Of 94 patients included, 38 (40%) developed radiographic DJK. 31 (39%) patients in whom the LIV was at or distal to the SSV developed DJK, whereas 7 (47%) in whom the LIV was proximal to the SSV developed DJK. 20 (59%) patients in whom the LIV was one vertebra below and 10 (22%) in whom the LIV was two vertebrae below the 1stLD developed DJK. Logistic regression demonstrated a significant increase in DJK development if the LIV was one vertebra below the 1stLD (OR = 3.2 (1.28-8.18)). There was not a significant relationship between DJK development and LIV position relative to the SSV. In SK surgery, LIV selection/fusion to two vertebrae below the 1stLD decreased the development of DJK. A significant relationship was not found between DJK development and location of distal fusion level in regards to the SSV, possibly due to the small number of patients who had LIV proximal to SSV.

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.

194. The effect of undercorrection on distal junctional kyphosis in adult cervical deformity patients

<h3>BACKGROUND CONTEXT</h3> Distal junctional kyphosis (DJK) development after cervical deformity (CD) corrective surgery is a growing concern for surgeons and patients. Although proper realignment is known to help mitigate the development of DJK, there has yet to be a study that critically analyzes under correction in certain parameters and the effects on development of DJK. <h3>PURPOSE</h3> To determine the effects of under correction in the development of DJK. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of single-center database. <h3>PATIENT SAMPLE</h3> This study included 195 CD patients. <h3>OUTCOME MEASURES</h3> Complications; radiographic parameters; HRQL metrics (NDI, EQ5D, mJOA, NRS Neck). <h3>METHODS</h3> Inclusion criteria: operative CD patients (cervical kyphosis >10°, with cSVA>4cm or CBVA>25°) and >18yrs with up to 2-year radiographic and HRQL follow-up. Significant differences in surgical, radiographic, and clinical factors and outcomes were determined. Under correction was defined by a deformity in TS-CL or cSVA Ames Modifier. Moderate Ames cervical lordosis deformity (CL) was TS-CL >15 and high >20, high cSVA deformity was >8cm. <h3>RESULTS</h3> A total of 195 CD patients met inclusion criteria (58.3yrs, 46% Female, 28.3 kg/m2). Overall, 40 (21%) of these patients developed DJK. At baseline patients presented with the following radiographic profile: PT (18.3), PI-LL (-.65), SVA C7-S1 (-6.54), cSVA C2-C7 (9.7), and TS-CL (24). Patients undercorrected in TS-CL developed DJK at a greater rate (28% vs 15%, p=.02), and patients undercorrected in cSVA developed more DJK (65% vs 16%) and underwent more reoperations (42% vs 17%, both p<0.05). Controlling for baseline deformity, frailty and age, patients who maintained a high cSVA deformity had a 3.2 times higher likelihood of developing DJK (3.2[1.6-6.8], p=.002). Patients with a postoperative moderate CL deformity had a 1.8 times higher likelihood of DJK (1.8[.9-3.8], p=.105), and with a high CL deformity, a 2.8 times higher likelihood (2.8[1.1-7.2], p=.03). Controlling for the same factors, patients who remained undercorrected in both cSVA and TS-CL had a 6 times times higher likelihood of developing DJK (6[1.9-17], p=.002). Using CIT to find a threshold cutoff, the risk of DJF was considerably increased for patients with a TS-CL greater than 13.5, (2.4[1.14-5], p=.026), and a cSVA deformity greater than 6cm (3.2[1.5-6.6], p=.026). Patients who were adequately corrected in cSVA and undercorrected in TS-CL demonstrated no significant increased vulnerability to DJK, (p>0.05). <h3>CONCLUSIONS</h3> The TS-CL and cSVA components of Ames criteria show a strong correlation with development of distal junctional kyphosis (DJK). Thresholds for DJK development suggests even patients who fall into a mild deformity as per the Ames criteria are still at an increased risk, and more strict alignment goals may further prevent mechanical failure. cSVA was found to be the dominant radiographic parameter impacting DJK development. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

237. The effect of sagittal alignment on adult cervical deformity patient outcomes, reoperation rates and development of distal junctional kyphosis

<h3>BACKGROUND CONTEXT</h3> Global spinal malalignment plays a vital role in cervical spinal deformity corrective surgery outcomes; however, the literature is scarce on the effects that the individual sagittal parameters have on outcomes. <h3>PURPOSE</h3> To investigate the impact of sagittal malalignment on cervical deformity patient outcomes. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of single-center database. <h3>PATIENT SAMPLE</h3> This study included 123 CD patients. <h3>OUTCOME MEASURES</h3> Complications; radiographic parameters; HRQL metrics (NDI, EQ5D, mJOA, NRS Neck) <h3>METHODS</h3> Inclusion criteria: operative CD patients (cervical kyphosis >10°, with cSVA >4cm or CBVA >25°) and >18yrs with up to 2Y radiographic and HRQL follow-up. Significant differences in surgical, radiographic, and clinical factors and outcomes were determined. Deformity in PT, SVA, and PILL was defined using the SRS-Schwab criteria. "Unmatched" refers to patients who were under corrected or over corrected according to the Schwab age-adjusted parameters (Lafage et al.). <h3>RESULTS</h3> A total of 123 CD patients met inclusion criteria (58.3 yrs, 46% Female, 28.3 kg/m2). Overall, 27 (24%) of these patients developed DJK. At baseline, patients presented with the following radiographic profile: PT (18.3), PILL (-.65), SVA C7-S1 (-6.54), cSVA C2-C7 (23.5), and TS-CL (25.2). Patients with DJK had a higher L1-S1 (34 vs 9.2) and T12-S1 (57 vs 35, both p<0.05) and trended towards a higher cSVA (-11.7 vs -3.7), C2-T3 (57.6 vs 37.4), and C2-S1 (17 vs 5.9, p>0.05). Patients with a deformity in PT at baseline developed more DJK by 2 years (26% vs 11%), had more DJF (7% vs 2%) and a higher NDI and NSR back pain. Patients with mismatch at baseline had higher rates of DJK (30% vs 22%), and patients with SVA deformity at baseline had a lower mJOA, SWAL Food selection, SWAL Communication, and a higher EQ5D. Patients with a mismatched alignment in Roussouly preoperatively had higher rates of DJK at 3M (18% vs 12%), 6M (26% vs 16%), 1Y (24% vs 14%), and 2Y (26% vs 13%, all p<0.05). Patients who were unmatched in SVA by 2Y had higher rates of DJK development at 2Y (25% vs 6%), and those unmatched in PILL by 2Y had higher rates of 2-year DJK (31% vs 19%) and higher 2-year NDI (38 vs 31). Patients who had a mismatch in Roussouly postoperatively had higher rates of DJK by 2 years (33% vs 23%, allp<0.05). <h3>CONCLUSIONS</h3> Global spinal malalignments play an important role in the outcomes of cervical spinal deformity corrective surgery. The presence of abnormal global sagittal malignment at baseline is associated with higher rates of DJK development and worse clinical outcomes, while patients who maintained poor sagittal alignment up to 2Y were associated with significantly greater development of DJK and inferior neck disability index scores. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

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.

Curve patterns deserve attention when determining the optimal distal fusion level in correction surgery for Scheuermann kyphosis

BACKGROUND CONTEXTThe surgical strategy to decide distal fusion level for Scheuermann kyphosis (SK) is controversial. Some spinal surgeons advocate that instrumentation should end at the first lordotic vertebra (FLV), whereas others recommend extending spinal fusion to the sagittal stable vertebra (SSV). Scheuermann kyphosis has two curve patterns: Scheuermann thoracic kyphosis (STK), with the curve apex above or at T10; and Scheuermann thoracolumbar kyphosis (STLK), with the curve apex below T10. To our knowledge, curve patterns have not been taken into consideration when determining the distal fusion level. PURPOSEThis study aims to analyze the clinical and radiographic outcomes, including the distal junctional problems, in pediatric patients with STK and STLK who underwent fusion with different distal fusion levels. STUDY DESIGNThis is a retrospective, single-center, institutional review board-approved study. PATIENT SAMPLEA total of 45 consecutive pediatric patients with STK or STLK. OUTCOME MEASURESThe following parameters were evaluated: global kyphosis (GK), deformity angular ratio (DAR), correction rate of GK and DAR, thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sagittal vertical axis (SVA), T1 pelvic angle (TPA), the distance from the center of the lower instrumented vertebra (LIV) to the posterior sacral vertical line, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and distal junctional kyphosis (DJK). METHODSThis work was supported by the National Natural Science Foundation of China (Grant No. 81171672), Nanjing Clinical Medical Center, and Jiangsu Provincial Key Medical Center. Patients with STK were fused to SSV at the distal level (Group STK), whereas patients with STLK were fused to FLV (Group STLK). Whole spine x-rays obtained before surgery, immediately after operation, and at the latest follow-up were evaluated. The radiographic and clinical data were compared between Groups STK and STLK. All patients had a minimum of 2 years of follow-up. RESULTSBefore surgery, Groups STK and STLK were comparable in terms of age, gender, body mass index, fusion levels, follow-up time, some radiographic parameters and the 22-item Scoliosis Research Society questionnaire (SRS-22) evaluation. DAR and TLK were significantly smaller, whereas PI was significantly greater, in Group STK than those in Group STLK. Despite different distal fusion strategies, STK and STLK were corrected to an equivalent extent, with similar GK, correction rate, LL, SVA, TPA, PT, and SS immediately after operation and at the final follow-up. The DAR and TLK retained were smaller, whereas the PI retained was greater, in Group STK than STLK after surgery. Distal junctional kyphosis complications were found in five patients with STK curve type. In Group STK, patients with DJK were found to have significantly larger preoperative GK (87.5±7.0 vs. 77.5±9.0, p=.024), correction rate of GK (62.9±10.2% vs. 51.3±8.5%, p=.021), and correction rate of DAR (55.9±4.5% vs. 36.6±13.7%, p=.011) than those without DJK. Pre- and postoperative SRS-22 assessments did not show any significant difference between Groups STK and STLK or between patients with and without DJK. CONCLUSIONSCurve patterns should be taken into attention when determining the optimal distal fusion level in correction surgery for SK. For patients with STLK, relatively shorter fusion stopping at FLV is enough to correct SK with the preservation of more lumbar motility and less development of DJK. For patients with STK, we suggest extending fusion to the SSV, which could restrict more distal junctional problems than fusion to the FLV. Large GK and correction degree might be the associated factors of developing DJK in STK patients.

SURGICAL TREATMENT OF A PATIENT WITH MULTIPLE FRACTURES OF THE THORACIC AND LUMBAR VERTEBRAE ASSOCIATED WITH HAJDU – CHENEY SYNDROME

A clinical case of surgical and multimodal conservative treatment of an 11-year-old female patient with Hajdu – Cheney syndrome with multiple vertebral fractures in the thoracic and lumbar spine is presented. The main and significant manifestations of this syndrome are osteoporosis and acroosteolysis. After the injury, the child underwent correction of posttraumatic spinal deformity and stabilization of spinal motion segments by a placement of multi-anchor instrumentation through a posterior approach. The long-term postoperative period was characterized by the absence of bone block formation, development of distal junctional kyphosis and scoliotic deformity, which required additional surgical intervention in the amount of elongation of instrumentation and correction of the developed curvature. The paper describes in detail the clinical manifestations of the syndrome, the results of surgical treatment, and clinical and radiological characteristics.

Preventing Distal Junctional Kyphosis by Applying the Stable Sagittal Vertebra Concept to Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

Study DesignMulticenter retrospective review. ObjectiveTo assess the effectiveness of using the stable sagittal vertebra (SSV) for selecting the lowest instrumented vertebrae (LIV) to prevent distal junctional kyphosis (DJK) in selective thoracic fusions. Summary of Background DataCho et al. reported that including the SSV in a fusion decreased the rate of DJK in thoracic hyperkyphosis. MethodsA retrospective review was performed of patients from two pediatric hospitals with adolescent idiopathic scoliosis who underwent selective posterior thoracic fusion with the LIV at L2 or above from 2000 to 2012. Patients with less than 2 years' follow-up were excluded. The primary outcome measure was DJK, defined radiographically as ≥10° between the superior end plate of the LIV and the inferior end plate of the vertebra below on a standing lateral radiograph. We investigated the SSV, which was defined as the vertebral level at which 50% of the vertebral body was in front of the posterior sacral vertical line (PSVL) on a standing lateral radiograph. This particular definition was referred to as SSV. ResultsA total of 113 patients met the inclusion criteria. Mean age was 14.4 years. Mean Cobb angle was 58°. The overall rate of DJK was 7% (8/113). When the LIV was superior to SSV, the rate of DJK was 17% (8/46) versus 0% (0/67) when the LIV was at or inferior to SSV (p=.01). The rates of DJK for patients with the LIV one, two, and three levels above SSV were 17% (4/24), 7% (1/14), and 43% (3/7), respectively. There was no significant association between preoperative or postoperative maximum kyphosis, thoracic kyphosis, thoracolumbar kyphosis, pelvic incidence, sagittal balance or coronal balance, and development of DJK. ConclusionAlthough LIV selection is complex, choosing the LIV at or below the SSV is a simple rule that minimizes the risk of DJK. Level of EvidenceLevel IV.

Selection Of The Optimal Level Of Distal Fixation For Correction Of Scheuermann's Hyperkyphosis.

To analyze the efficacy of the method for selecting the distal level of fusion in treatment of thoracic hyperkyphosis in patients with Scheuermann's disease. The fusion area needs to include all the kyphotic deformity in Scheuermann patients; however, precise levels of the distal fixation have not been determined yet. Retrospective cohort review. Thirty-six patients were operated in the Department of Children and Adolescent Spine Pathology between 2007 and 2010. These patients were divided into two groups: in group I (n = 29) a lower instrumented vertebra corresponded to the sagittal stable one and in group II (n = 7) - this vertebra located proximally. The mean preoperative kyphosis was 79.3° ± 11.6°, the postoperative - 40.6° ± 11.9° (correction of 49.9%), loss of correction was 4.9° ± 7.0°. Sagittal balance changed from -0.3 ± 3.2 cm before surgery to -1.7 ± 2.1 cm after surgery. Distal junctional kyphosis developed in 1 case (4%) in Group I, and in 5 cases (71%) in Group II. A distal level of instrumentation ending at the first lordotic vertebra is not justified and causes violation of sagittal balance and development of distal junctional kyphosis. The inclusion of a sagittal stable vertebra in fusion prevents the development of this undesirable situation.

Thoracic Hyperkyphosis: Assessment of the Distal Fusion Level

Study Design This is a retrospective study. Objective The objective of this study was to assess the sagittal stable vertebra (SSV) versus the first lordotic vertebra (FLV) as the inferior fusion level in patients undergoing spinal surgery for thoracic hyperkyphosis. The main outcome of interest was the development of distal junctional kyphosis (DJK). Summary of Background Data Prior research has pointed to selection of the FLV for the distal instrumentation level in fusion for thoracic hyperkyphosis. In 2009, Cho et al introduced the concept of the SSV after recognizing the development of DJK despite fusion to the FLV. Methods Patients were reviewed who had undergone spinal fusion for thoracic hyperkyphosis. Preoperative radiographs were reviewed to assess thoracic kyphosis, lumbar lordosis, SSV, and FLV. Postoperative radiographs were reviewed to assess curve correction and whether patients developed DJK or implant failure. Results We reviewed 22 patients with a mean age at surgery of 18 (range 14 to 22). Mean preoperative kyphosis was 85 ± 14 degrees, and mean postoperative kyphosis at final follow-up was 59 ± 12 degrees for a mean correction of 26 ± 12 degrees. Eleven patients developed DJK and four patients experienced hardware failure. In 12 patients, the SSV was inferior to the FLV. Rates of DJK when the instrumentation included the SSV or FLV were 13 and 38%, respectively. Conclusions Fusion to the SSV is superior at preventing DJK when compared with fusion to the FLV.

Incidence and Risk Factors for Proximal and Distal Junctional Kyphosis Following Surgical Treatment for Scheuermann Kyphosis

Retrospective case review at a single center. To analyze the incidence and risk factors associated with proximal junctional kyphosis (PJK) and distal junctional kyphosis (DJK) in patients undergoing instrumented spinal fusion for Scheuermann kyphosis. Previously reported risk factors for junctional kyphosis include improper end vertebrae selection, curve correction greater than 50%, or excessive junctional soft tissue dissection. Clinical and radiographic data on 67 patients (mean age 37) from a single center treated with instrumented fusion for Scheuermann kyphosis were reviewed. All patients had complete radiographic data with a minimum 5-year follow-up (mean: 73 months). Abnormal PJK was defined by a proximal junctional angle greater than 10 degrees and at least 10 degrees greater than the corresponding preoperative measurement. DJK was similarly defined between the caudal endplate of the lower instrumented vertebra to the caudal endplate that was 1 vertebra below. The incidence of PJK as defined above was seen in 20 patients (30%). The development of PJK was associated with failure to incorporate the proximal end vertebra (15 patients), disruption of junctional ligamentum flavum (3 patients), or combination of both (2 patients). The most common cause of inappropriate end vertebra selection was poor visualization of the upper thoracic vertebra.DJK occurred in 8 patients (12%) and 7 of them had fusion short of including the first lordotic disc. The incidence of PJK can be minimized by the appropriate selection of the upper end vertebra to be fused and avoiding disruption of the junctional ligamentum flavum. The development of DJK can be minimized by incorporation of the first lordotic disc into the fusion construct.

Distal Junctional Kyphosis of Adolescent Idiopathic Thoracic Curves Following Anterior or Posterior Instrumented Fusion: Incidence, Risk Factors, and Prevention

This is a retrospective multicenter analysis of a subset of 375 patients with thoracic adolescent idiopathic scoliosis (AIS) treated with either anterior (238) or posterior (137) fusion with preoperative or postoperative distal junctional kyphosis (DJK) >or=10 degrees . To determine the incidence of DJK before and after surgery in patients with AIS undergoing either anterior or posterior thoracic fusion, and provide recommendations for prevention. DJK following surgical treatment for AIS may result in pain, imbalance, and unacceptable deformity. The true incidence of DJK following selective anterior or posterior instrumentation and fusion is unknown, as are "risk factors" for its development. Mean age at surgery was 14.4 years (range 9.1-20.9) in the anterior group and 14.7 years (range 10.2-20.7) in the posterior. Analysis included the Cobb and instrumented levels of the thoracic curves, and sagittal measurements, all on preoperative and 2-year follow-up standing 36-in radiographs. In the anterior group, the incidence of preoperative DJK was 4.2%, and postoperative DJK was 7.1%. In the posterior group, the incidence of preoperative DJK was 5.0% and 14.6% after surgery. When postoperative DJK developed in the posterior group, mean postoperative T10-L2 was +17 degrees kyphosis compared to +2 degrees in the posterior group without DJK (P < 0.001). When postoperative DJK developed in the anterior group, mean postoperative T10-L2 was +12 degrees kyphosis compared to +2 degrees for the anterior group without DJK (P = 0.006). DJK was significantly more likely to occur in the posterior group if the Cobb was instrumented to less than Cobb +1 (P < 0.001). It appears that both posterior and anterior instrumentation for thoracic curves must include the junctional level to prevent postoperative DJK when postoperative DJK is present. The presence of increased kyphosis after surgery in the T10-L2 region seen in both anterior and posterior groups that had postoperative DJK develop constitutes a "risk factor" for the development of DJK.

Scheuermann's kyphosis in adolescents and adults: diagnosis and management.

Scheuermann's thoracic kyphosis is a structural deformity classically characterized by anterior wedging of 5 degrees or more of three adjacent thoracic vertebral bodies. Secondary radiographic findings of Schmorl's nodes, endplate narrowing, and irregular endplates confirm the diagnosis. The etiology remains unclear. Adolescents typically present to medical attention because of cosmetic deformity; adults more commonly present because of increased pain. The indications for treatment are similar to those for other spinal deformities, namely, progression of the deformity, pain, neurologic compromise, and cosmesis. The adolescent with pain associated with Scheuermann's kyphosis usually responds to physical therapy and a short course of anti-inflammatory medications. Bracing has been shown to be effective in controlling a progressive curve in the adolescent patient. For the adult who presents with pain, the early mainstays of treatment are physical therapy, anti-inflammatory medications, and behavioral modification. In patients, either adolescent or adult, with a progressive deformity, refractory pain, or neurologic deficit, surgical correction of the deformity may be indicated. Surgical correction should not exceed 50% of the initial deformity. Distally, instrumentation should be extended beyond the end vertebral body to the first lordotic disk to prevent the development of distal junctional kyphosis.