Twelve to Twenty-year Follow-up of Dega Acetabuloplasty in Patients With Developmental Dysplasia of the Hip: Is it as Effective as Expected?

BACKGROUND: Although Dega acetabuloplasty is widely used for the treatment of developmental dysplasia of the hip, there is a paucity of data on long-term outcomes. The purpose of the study was to evaluate the rate of residual acetabular dysplasia after Dega acetabuloplasty. METHODS: Patients of a previously reported consecutive series of 35 patients (43 hips) operated by a single surgeon were recontacted for long-term follow-up. Of these, 25 patients (32 hips) consented, with a follow-up rate of 71% (74% of hips). The mean age at the time of surgery was 35 (18 to 65) months. The presence of residual dysplasia was noted according to the lateral center-edge angle of Wiberg, femoral head extrusion index, and Tönnis angle. The latest radiographic outcome was evaluated according to the Severin classification and patients were clinically evaluated according to the modified McKay criteria. RESULTS: The mean follow-up duration of 16.5 (12 to 20) years yielded an average age of 19.2 (14 to 23) years at the time of analysis. According to lateral center-edge angle, femoral head extrusion index, and Tönnis angle, 5 (15.6%) hips were dysplastic and 2 (6.3%) hips were reoperated for resubluxation. Thus, a total of 7 hips (21.9%) were considered to have residual dysplasia. With the exception of 2 hips that underwent further osteotomies, no other hips were re-subluxated or redislocated. Overcoverage was noted in 6 (18.7%) hips. There were 26 Severin group I and II (81.3%), 4 Severin group III (12.5%), and 2 Severin group IV (6.2%) hips. According to modified McKay criteria, 20 (62.5%) hips were excellent, 7 (21.9%) hips were good, and 5 (15.6%) were fair. Severin classification and modified McKay criteria were correlated with dysplasia ( P < 0.05). CONCLUSIONS: Seventy-eight percent of the hips treated by Dega acetabuloplasty for developmental dysplasia of the hip did not have acetabular dysplasia at a mean follow-up of 16 years. Even in well-treated asymptomatic hips, patients should be followed regularly, especially for residual dysplasia. LEVEL OF EVIDENCE: Level IV.

Sagittal realignment: surgical restoration of the global alignment and proportion score parameters: a subgroup analysis. What are the consequences of failing to realign?

INTRODUCTION: The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version-RPV, relative lumbar lordosis-RLL, lumbar distribution index-LDI) and one indirectly restored (relative spinopelvic alignment-RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs. MATERIALS AND METHODS: From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed. RESULTS: The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the "Severe hypolordosis" and "Hyperlordosis" subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w (p = 0.025) and RSA-6w (p = 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion (p = 0.026) and severe positive malalignment (p = 0.007) were risk factors for mechanical complications. RSA-6w "Severe positive malalignment" was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2; p = 0.011), ∆SRS-22 total (0.54 vs 0.87; p = 0.007), and ∆SF-36PCS (3.47 vs 7.76; p = 0.04); MCID for ODI (37.0 vs 55.5%; p = 0.023), and SRS-22 (40.8 vs 60.1%; p = 0.015); and PASS for ODI (17.6 vs 31.7%; p = 0.047). CONCLUSIONS: RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.

Revision surgery following long lumbopelvic constructs for adult spinal deformity: prospective experience from two dedicated databases.

PURPOSE: Pan Lumbar Arthodesis (PLA) are often required for Adult Spinal Deformity (ASD) correction, reducing significantly the compensatory capacity in case of postoperative sagittal malalignment. Few papers have investigated outcomes and complications in this vulnerable subset of patients. The objective of this study was to assess revision surgery rate for PLA in ASD, its risk factors and impact on clinical outcomes. METHODS: Retrospective multicenter review of prospective ASD data from 7 hospitals covering Europe and Asia. ASD patients included in two prospective databases having a posterior instrumentation spanning the whole lumbar region with more than 2-years of follow-up were reviewed. Demographic, surgical, radiographic parameters and Health-Related Quality of Life (HRQoL) scores were analyzed. Univariate and multivariate regression models analyzed risk factors for revision surgery as well as surgical outcomes. Patients with Early versus Late and PJK versus Non-PJK mechanical complications were also compared. RESULTS: Out of 1359 ASD patients included in the database 589 (43%) had a PLA and 357 reached 2-years mark. They were analyzed and compared to non-PLA patients. Average age was 67 and 82% were females. 100 Patients (28.1%) needed 114 revision surgeries (75.4% for mechanical failures). Revised patients were more likely to have a nerve system disorder, higher BMI and worst immediate postoperative alignment (as measured by GAP Parameters). These risk factors were also associated with earlier mechanical complications and PJK. Deformity and HRQoL parameters were comparable at baseline. Non-revised patients had significantly better clinical outcomes at 2-years (SRS 22 scores, ODI, Back pain). Multivariate analysis could identify nerve system disorder (OR 4.8; CI 1.8-12.6; p = 0.001), postoperative sagittal alignment (GAP Score) and high BMI (OR 1.07; CI 1.01-1.13; p = 0.004) as independent risk factors for revisions. CONCLUSIONS: Revision surgery due to mechanical failures is relatively common after PLA leading to worse clinical outcomes. Prevention strategies should focus on individualized restoration of sagittal alignment and better weight control to decrease stress on these rigid constructs in non-compliant spines. Nerve system disorders independently increase revision risk in PLA. LEVEL OF EVIDENCE II: Prognosis.

Relationship between pelvic incidence-adjusted relative spinopelvic parameters, global sagittal alignment and lower extremity compensations.

PURPOSE: In response to sagittal malalignment, compensatory spinal and lower extremity mechanisms are recruited. Thoracolumbar realignment surgery has been shown to yield reciprocal changes in these compensations. Thus, whole-body radiographic assessment has come to the fore. This study aimed to evaluate the relationship between spinopelvic parameters and lower extremity compensation angles and to examine their coupled change with deformity correction. METHODS: This was a multicenter retrospective analysis of patients who had ≥ 4 levels posterior fusion, whole-body radiographs, and ≥ 2 years follow-up. Relative Pelvic Version (RPV), Relative Lumbar Lordosis (RLL), Relative Spinopelvic Alignment (RSA), Femoral Obliquity Angle (FOA), Knee Flexion Angle (KFA) and Global Sagittal Axis (GSA) were measured preoperatively and 6 week postoperatively. Kruskal-Wallis tests were performed to assess the relation of relative spinopelvic parameters to global sagittal alignment and lower extremity compensation angles. Spearman's correlations were performed to assess correlations of pre-to-postoperative changes. RESULTS: 193 patients (156F, 37 M) were included. The mean age was 57.2 ± 16.6 years. The mean follow-up duration was 50.6 (24-90) months. On average, 10.3 ± 3.8 levels were fused. Among the cohort, 124 (64.2%) had a sacral or sacroiliac fixation, and 43 (22.3%) had 3-column osteotomies. Preoperative FOA, KFA and GSA significantly differed between RPV, RLL and RSA categories. Significant weak-to-strong correlations were observed between spinopelvic parameters, global sagittal alignment and lower extremity compensation angles (rho range: - 0.351 to 0.767). CONCLUSIONS: PI-adjusted relative spinopelvic parameters significantly correlated with measurements of the lower extremity compensation. Postoperative changes in RPV, RLL and RSA reflected changes in FOA, KFA and GSA. These measurements may serve as a valuable proxy for surgical planning when whole-body imaging is not available.

Association between sagittal alignment and loads at the adjacent segment in the fused spine: a combined clinical and musculoskeletal modeling study of 205 patients with adult spinal deformity.

PURPOSE: Sagittal malalignment is a risk factor for mechanical complications after surgery for adult spinal deformity (ASD). Spinal loads, modulated by sagittal alignment, may explain this relationship. The aims of this study were to investigate the relationships between: (1) postoperative changes in loads at the proximal segment and realignment, and (2) absolute postoperative loads and postoperative alignment measures. METHODS: A previously validated musculoskeletal model of the whole spine was applied to study a clinical sample of 205 patients with ASD. Based on clinical and radiographic data, pre-and postoperative patient-specific alignments were simulated to predict loads at the proximal segment adjacent to the spinal fusion. RESULTS: Weak-to-moderate associations were found between pre-to-postop changes in lumbar lordosis, LL (r = - 0.23, r = - 0.43; p < 0.001), global tilt, GT (r = 0.26, r = 0.38; p < 0.001) and the Global Alignment and Proportion score, GAP (r = 0.26, r = 0.37; p < 0.001), and changes in compressive and shear forces at the proximal segment. GAP score parameters, thoracic kyphosis measurements and the slope of upper instrumented vertebra were associated with changes in shear. In patients with T10-pelvis fusion, moderate-to-strong associations were found between postoperative sagittal alignment measures and compressive and shear loads, with GT showing the strongest correlations (r = 0.75, r = 0.73, p < 0.001). CONCLUSIONS: Spinal loads were estimated for patient-specific full spinal alignment profiles in a large cohort of patients with ASD pre-and postoperatively. Loads on the proximal segments were greater in association with sagittal malalignment and malorientation of proximal vertebra. Future work should explore whether they provide a causative mechanism explaining the associated risk of proximal junction complications.

Combined anterior-posterior versus all-posterior approaches for adult spinal deformity correction: a matched control study.

PURPOSE: Anterior approaches are gaining popularity for adult spinal deformity (ASD) surgeries especially with the introduction of hyperlordotic cages and improvement in MIS techniques. Combined Approaches provide powerful segmental sagittal correction potential and increase the surface area available for fusion in ASD surgery, both of which would improve overall. This is the first study directly comparing surgical outcomes between combined anterior-posterior approaches and all-posterior approach in a matched ASD population. METHODS: This is a retrospective matched control cohort analysis with substitution using a multicenter prospectively collected ASD data of patients with > 2 year FU. Matching criteria include: age, American Society of Anesthesiologists Score, Lumbar Cobb angle, sagittal deformity (Global tilt) and ODI. RESULTS: In total, 1024 ASD patients were available for analysis. 29 Combined Approaches patients met inclusion criteria, and only 22 could be matched (1:2 ratio). Preoperative non-matched demographical, clinical, surgical and radiological parameters were comparable between both groups. Combined approaches had longer surgeries (548 mns vs 283) with more blood loss (2850 ml vs 1471) and needed longer ICU stays (74 h vs 27). Despite added morbidity, they had comparable complication rates but with significantly less readmissions (9.1% vs 38.1%) and reoperations (18.2% vs 43.2%) at 2 years. Combined Approaches achieved more individualised and harmonious deformity correction initially. At the 2 years control, Combined Approaches patients reported better outcomes as measured by COMI and SRS scores. This trend was maintained at 3 years. CONCLUSION: Despite an increased initial surgical invasiveness, combined approaches seem to achieve more harmonious correction with superior sagittal deformity control; they need fewer revisions and have improved long-term functional outcomes when compared to all-posterior approaches for ASD deformity correction.

Compensatory mechanisms recruited against proximal junctional kyphosis by patients instrumented from the thoracolumbar junction to the iliac.

PURPOSE: The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients. MATERIAL AND METHODS: We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses. RESULTS: A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc. CONCLUSIONS: In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.

Surgeons' risk perception in ASD surgery: The value of objective risk assessment on decision making and patient counselling.

BACKGROUND: Surgeons often rely on their intuition, experience and published data for surgical decision making and informed consent. Literature provides average values that do not allow for individualized assessments. Accurate validated machine learning (ML) risk calculators for adult spinal deformity (ASD) patients, based on 10 year multicentric prospective data, are currently available. The objective of this study is to assess surgeon ASD risk perception and compare it to validated risk calculator estimates. METHODS: Nine ASD complete (demographics, HRQL, radiology, surgical plan) preoperative cases were distributed online to 100 surgeons from 22 countries. Surgeons were asked to determine the risk of major complications and reoperations at 72 h, 90 d and 2 years postop, using a 0-100% risk scale. The same preoperative parameters circulated to surgeons were used to obtain ML risk calculator estimates. Concordance between surgeons' responses was analyzed using intraclass correlation coefficients (ICC) (poor < 0.5/excellent > 0.85). Distance between surgeons' and risk calculator predictions was assessed using the mean index of agreement (MIA) (poor < 0.5/excellent > 0.85). RESULTS: Thirty-nine surgeons (74.4% with > 10 years' experience), from 12 countries answered the survey. Surgeons' risk perception concordance was very low and heterogeneous. ICC ranged from 0.104 (reintervention risk at 72 h) to 0.316 (reintervention risk at 2 years). Distance between calculator and surgeon prediction was very large. MIA ranged from 0.122 to 0.416. Surgeons tended to overestimate the risk of major complications and reintervention in the first 72 h and underestimated the same risks at 2 years postop. CONCLUSIONS: This study shows that expert surgeon ASD risk perception is heterogeneous and highly discordant. Available validated ML ASD risk calculators can enable surgeons to provide more accurate and objective prognosis to adjust patient expectations, in real time, at the point of care.

The classification of scoliosis braces developed by SOSORT with SRS, ISPO, and POSNA and approved by ESPRM.

PURPOSE: Studies have shown that bracing is an effective treatment for patients with idiopathic scoliosis. According to the current classification, almost all braces fall in the thoracolumbosacral orthosis (TLSO) category. Consequently, the generalization of scientific results is either impossible or misleading. This study aims to produce a classification of the brace types. METHODS: Four scientific societies (SOSORT, SRS, ISPO, and POSNA) invited all their members to be part of the study. Six level 1 experts developed the initial classifications. At a consensus meeting with 26 other experts and societies' officials, thematic analysis and general discussion allowed to define the classification (minimum 80% agreement). The classification was applied to the braces published in the literature and officially approved by the 4 scientific societies and by ESPRM. RESULTS: The classification is based on the following classificatory items: anatomy (CTLSO, TLSO, LSO), rigidity (very rigid, rigid, elastic), primary corrective plane (frontal, sagittal, transverse, frontal & sagittal, frontal & transverse, sagittal & transverse, three-dimensional), construction-valves (monocot, bivalve, multisegmented), construction-closure (dorsal, lateral, ventral), and primary action (bending, detorsion, elongation, movement, push-up, three points). The experts developed a definition for each item and were able to classify the 15 published braces into nine groups. CONCLUSION: The classification is based on the best current expertise (the lowest level of evidence). Experts recognize that this is the first edition and will change with future understanding and research. The broad application of this classification could have value for brace research, education, clinical practice, and growth in this field.

How frequent should the radiographic examination be to monitor magnetically controlled growing rods? A retrospective look two to seven years postoperatively.

PURPOSE: Magnetically controlled growing rods (MCGR) allow more frequent outpatient lengthenings to better mimic the physiological growth. The assessment of distractions with radiographs raised concerns regarding ionizing radiation exposure in growing children. The aim was to assess the necessity of radiographs after every lengthening of MCGR. METHODS: A retrospective analysis of 30 consecutive patients (19F, 11 M) treated in a single institution between 2011 and 2017. Planned radiographs were taken based on a protocol, updated over the years to involve less frequent acquisitions. Unplanned radiographs were obtained after a patient complaint or a significant clinical examination finding. Outcome measures were preoperative and postoperative radiographic measurements, and complications such as proximal and distal junctional kyphosis and failure, rod or actuator breakage, collapse of previously achieved height or failure to lengthen and worsening of deformity. RESULTS: Mean age at surgery was 7.5 (4-11) years. Mean follow-up was 45 (24-84) months. Mean number of lengthenings and radiographs per patient were 14.4 (8-23), and 13.2 (5-46), respectively. Nine patients (30%) experienced a total of 13 mechanical complications. Almost all complications were detected in unplanned radiographs. The probability of detecting a mechanical complication was significantly lower (p < 0.00001) in planned radiographs. CONCLUSIONS: Radiographs taken after routine lengthenings of MCGR are not likely to reveal any significant finding, since only 0.9% of planned radiographs displayed a mechanical complication. Exposing growing children to radiation with an intention of checking the MCGR device after every lengthening could not be justified. Obtaining post-lengthening radiographs with a decreased frequency and after a significant complaint or clinical finding may be considered.

Static and dynamic sagittal lumbar apex: a new concept for the assessment of lumbar lordosis distribution in spinal deformity.

PURPOSE: Sagittal lumbar apex has been demonstrated to be a key parameter in sagittal plane morphology. Our aim was to understand its behavior with postural changes, analyzing two different concepts of lumbar apex. MATERIALS AND METHODS: Prospective observational study with a cohort of patients presenting sagittal malalignment identified from a monocenter database of adult spinal deformities (ASD). Inclusion criteria were age > 30 years, SVA > 40 mm, and/or PT > 20. All patients had full-spine EOS radiographs in 2 different positions: (P1: natural position) and position 2 (P2: compensated position). Sagittal alignment, spinopelvic values, and two different methods of assessing lordosis apex location were analyzed in both P1 and P2 positions. Changes between P1 and P2 were compared using a paired t test with a significance level at p < 0.05. RESULTS: Twenty-five patients were recruited (21 women and 4 men). The mean age was 64.8 years (range 21-79). The patient's main compensation was based on an increase in the femoral shaft angle, and pelvic retroversion, with a subsequent decrease in sacral slope, and therefore of the lower lumbar arc. When the lumbar apex was calculated as the most anterior point touching the vertical line in a lateral radiograph, postural compensation changes modified its location usually shifting it to a more caudal position. When the lumbar apex was assessed as the most distant point of the global lumbar lordosis, its position remained stable regardless of compensation. CONCLUSIONS: Postural changes can modify the location of the lumbar apex when understanding its location as the cornerstone of sagittal plane harmonic distribution. This concept can be useful as an additional sign to assess compensation. However, if the lumbar apex was calculated as the angular point of the global lordosis, its position remained stable regardless of postural changes. This concept can help to mold lumbar lordosis in ASD surgery. LEVEL OF EVIDENCE IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Effect of lumbar pedicle subtraction osteotomy level on lordosis distribution and shape.

PURPOSE: Little is known about the qualitative results (postoperative upper/lower lumbar arches distribution and lumbar apex or inflection point positioning) of lumbar pedicle subtraction osteotomies (L-PSO) depending on the level of L-PSO. METHODS: We conducted a retrospective analysis of prospectively collected data of adult deformity patients undergoing single-level L-PSO. We analyzed several variables in preoperative and postoperative sagittal radiographs: L-PSO level, Roussouly classification (R-type), inflection point (InfP), lumbar apex (LApex), spinopelvic parameters, lordosis distribution index (LDI = L4-S1/L1-S1), and number of levels in the lordosis (NVL). Comparisons between PSO levels were performed to determine lordosis distribution and sagittal shape using ANOVA test and Chi-squared statistics. RESULTS: A total of 126 patients were included in this study. L5-PSO mainly increased the lower lumbar arch, thereby increasing LDI. L4 increased upper/lower arches similarly. PSOs at and above L3 increased the upper lumbar arch, thereby decreasing LDI (P < 0.001). L4-PSO added 1 vertebra into the lordosis (NVL = + 1.2 ± 2.2). PSOs above L3 added 2 vertebrae into the lordosis (NVL = + 2.3 ± 1.4). Overall P = 0.007. PSOs above L4 shifted the LApex cranially in 70% of the cases (mean 1.12 levels) and the InfP in 85% of the cases (mean 2.4 levels). L5-PSO shifted the LApex caudally in 70% of the cases (mean - 1.1 levels) and the InfP in 50% of the cases (mean - 1.6 levels). Overall P < 0.006. The L-PSO level was not associated with a specific Roussouly-type P > 0.05. CONCLUSIONS: The level of L-PSO influenced upper/lower lumbar arches distribution, and lumbar apex and inflection point positioning. The correct level should be chosen based on the individual assessment of each patient.

Restoring the ideal Roussouly sagittal profile in adult scoliosis surgery decreases the risk of mechanical complications.

PURPOSE: There are still no data proving whether restoring the ideal sagittal profile (according to Roussouly classification) in adult scoliosis (AS) patients leads to any additional benefit, especially regarding mechanical complications. METHODS: Retrospective analysis of operated AS patients recorded in a prospective multicenter database. Demographic and radiographic (preoperative and 6-week postoperative) data were analyzed. Patients with and without mechanical complications were compared looking especially at the surgical restoration of the ideal (based on Pelvic Incidence) sagittal profile. Univariate and multivariate analysis was performed to identify causes of mechanical complications at 2-year minimum follow-up. RESULTS: Ninty-six AS patients were analyzed. Thirty-nine patients suffered a mechanical complication (18 PJK, 11 pseudoarthrosis, 10 screw pull-out), and 57 patients had no mechanical complications. Postoperatively, 72% of patients not matching the ideal Roussouly-type suffered mechanical complications compared to 15% of matched patients (P < 0.001). Univariate analysis showed that older patients 64.9 ± 13 versus 40.7 ± 15.6 years (P < 0.001), higher postoperative Global Tilt (27° vs. 14.7°) and Pelvic Tilt (25° vs. 16°) (P < 0.001), upper instrumented vertebra at the thoracolumbar junction (62% vs. 21%) (P < 0.001), fixation to the Iliac (76% vs. 6%) (P < 0.001), and postoperative Roussouly-type mismatch (72% vs. 15%) (P < 0.001) significantly increased the rate of mechanical complications. Multivariate logistic regression analysis selected: postoperative Roussouly-type mismatch (OR = 41.9; 95%CI = 5.5-315.7; P < 0.001), iliac instrumentation (OR = 19.4; 95%CI = 2.6-142.5; P = 0.004), and age (OR = 1.1; 95%CI = 1.02-1.16; P = 0.004), as the most important variables. CONCLUSIONS: Adult scoliosis surgery should restore the ideal Roussouly sagittal profile to decrease the rate of mechanical complications, especially in patients older than 65, instrumented to the pelvis. These slides can be retrieved under Electronic Supplementary Material.

Lack of improvement in health-related quality of life (HRQOL) scores 6 months after surgery for adult spinal deformity (ASD) predicts high revision rate in the second postoperative year.

PURPOSE: ASD is assessed radiologically with the spinopelvic parameters and clinically with HRQOL scores. The revision rate after ASD surgery is high and usually occurs during the first or second postoperative year. The aim of this study is to find clinical or radiological factors that could predict revision surgery in the second postoperative year. MATERIALS AND METHODS: Inclusion criterion: ASD patients operated on by instrumented posterior fusion with more than 2 years follow-up were enrolled prospectively. Additional criterion was no revision surgery during the first postoperative year. From a multicenter database of 560 operated ASD patients, 164 patients met these criteria. The patients were divided into two groups depending on the need of revision surgery during the second postoperative year. Preoperative, 6-month, 1-year and 2-year data were collected and compared for both groups. RESULTS: A total of 22 patients needed revision surgery and 142 did not. All revisions were for mechanical complications (non-fusion and implant related). Preoperatively, there was a significant difference between the groups (no revision vs. revision) for age (48 vs. 60 years), ODI (37 vs. 53), and SVA (29 vs. 76 mm), respectively. At 6 months, a significant difference in sagittal alignment was found, though HRQOL scores were similar. At 1 year, the no revision group scores improved, whereas the revision group scores remained stable or worsened. At 2 years, the no revision group scores remained stable. Comparing 6- and 12-month data, patients with improved, stable and worsened HRQOL scores had 8, 15 and 28% revision rates, respectively. CONCLUSION: The revision rate at the second-year post-surgery (13.4%) remains high and demonstrated that a 2-year follow-up is mandatory. In addition to usual risk factors for mechanical complications in ASD surgery, stabilization or worsening of the HRQOL scores between the 6th and 12th month postop was highly predictive of revision rate. This observation is beneficial for ASD patient follow-up as clinical symptoms clearly precede mechanical failure.

Relative lumbar lordosis and lordosis distribution index: individualized pelvic incidence-based proportional parameters that quantify lumbar lordosis more precisely than the concept of pelvic incidence minus lumbar lordosis.

OBJECTIVE The subtraction of lumbar lordosis (LL) from the pelvic incidence (PI) offers an estimate of the LL required for a given PI value. Relative LL (RLL) and the lordosis distribution index (LDI) are PI-based individualized measures. RLL quantifies the magnitude of lordosis relative to the ideal lordosis as defined by the magnitude of PI. LDI defines the magnitude of lower arc lordosis in proportion to total lordosis. The aim of this study was to compare RLL and PI - LL for their ability to predict postoperative complications and their correlations with health-related quality of life (HRQOL) scores. METHODS Inclusion criteria were ≥ 4 levels of fusion and ≥ 2 years of follow-up. Mechanical complications were proximal junctional kyphosis/proximal junctional failure, distal junctional kyphosis/distal junctional failure, rod breakage, and implant-related complications. Correlations between PI - LL, RLL, PI, and HRQOL were analyzed using the Pearson correlation coefficient. Mechanical complication rates in PI - LL, RLL, LDI, RLL, and LDI interpreted together, and RLL subgroups for each PI - LL category were compared using chi-square tests and the exact test. Predictive models for mechanical complications with RLL and PI - LL were analyzed using binomial logistic regressions. RESULTS Two hundred twenty-two patients (168 women, 54 men) were included. The mean age was 52.2 ± 19.3 years (range 18-84 years). The mean follow-up was 28.8 ± 8.2 months (range 24-62 months). There was a significant correlation between PI - LL and PI (r = 0.441, p < 0.001), threatening the use of PI - LL to quantify spinopelvic mismatch for different PI values. RLL was not correlated with PI (r = -0.093, p > 0.05); therefore, it was able to quantify divergence from ideal lordosis for all PI values. Compared with PI - LL, RLL had stronger correlations with HRQOL scores (p < 0.05). Discrimination performance was better for the model with RLL than for PI - LL. The agreement between RLL and PI - LL was high (κ = 0.943, p < 0.001), moderate (κ = 0.455, p < 0.001), and poor (κ = -0.154, p = 0.343), respectively, for large, average, and small PI sizes. When analyzed by RLL, each PI - LL category was further divided into distinct groups of patients who had different mechanical complication rates (p < 0.001). CONCLUSIONS Using the formula of PI - LL may be insufficient to quantify normolordosis for the whole spectrum of PI values when applied as an absolute numeric value in conjunction with previously reported population-based average thresholds of 10° and 20°. Schwab PI - LL groups were found to constitute an inhomogeneous group of patients. RLL offers an individualized quantification of LL for all PI sizes. Compared with PI - LL, RLL showed a greater association with both mechanical complications and HRQOL. The use of RLL and LDI together, instead of PI - LL, for surgical planning may result in lower mechanical complication rates and better long-term HRQOL.

Comparison of magnetic resonance imaging findings with arthroscopic findings in discoid meniscus.

PURPOSE: It is widely accepted that although valuable in the diagnosis of the discoid meniscus and tears, magnetic resonance imaging (MRI) can be insufficient in determining the type of the tear. This study calculates the sensitivity and specificity of MRI in determining the presence and absence of tears and how these values differ for different types of tears. METHODS: This study is a retrospective review of 10 years of our experience with arthroscopic discoid meniscus treatment between 1999 and 2009. MRI findings were compared with the intraoperative arthroscopic findings in 52 patients with 50 lateral and two medial discoid menisci of which 24 were complete and 28 were incomplete. Tears were classified into six groups: (1) no tear, (2) simple horizontal tear, (3) radial tear, (4) combined horizontal tear, (5) complex tear and (6) longitudinal tear. Sensitivity, specificity, positive and negative predictive values of MRI were calculated for each group separately and for the presence and absence of tears in general. In addition, the effect of age, type of discoid meniscus, and presence and absence of shift on the distribution of tear types were analysed. RESULTS: MRI was found to be 100 % specific and 97.8 % sensitive for determining the presence or absence of a tear with a negative predictive value of 85.7 % and a positive predictive value of 100 %. The specificities were 80 % for simple horizontal, 50 % for radial, 66.7 % for combined horizontal, 55.6 % for complex and 14.3 % for longitudinal tears, whereas the sensitivities were 66.7 % for simple horizontal, 96.9 % for radial, 87.5 % for combined horizontal, 94.6 % for complex and 100 % for longitudinal tears. The presence and absence of shift and type of the discoid were found to affect the distribution of the tear type. CONCLUSIONS: MRI is successful in determining the presence or absence of tears in discoid menisci; however, its ability to determine the tear type is questionable. Complete discoid menisci were found to have tendency towards having a simple horizontal or longitudinal tear, whereas incomplete discoid menisci tend to have radial or combined horizontal tears. Determination of the shift prior to surgery is important since it alters the surgical technique.

Effects of the fusionless instrumentation on the disks and facet joints of the unfused segments: a pig model.

BACKGROUND: Growing rod (GR) is a state-of-the-art procedure favored when curvatures of the spine cannot be managed nonoperatively in early-onset scoliosis. Although some postulate that multiple distractions and/or relative immobilization of the unfused segments affect the health of disk and facet joint (FJ) and cause degeneration and/or spontaneous fusion, this has not thoroughly been investigated. In this study, changes in the unfused segment after a spine-based fusionless instrumentation (SBFI) are investigated and compared with the control (CG) and instrumented fusion (IF) groups. METHODS: A total of 13 piglets, 10 to 14 weeks of age, were used. SBFI and IF were performed on 7 and 3 piglets, respectively, and 3 formed the CG. In SBFI, lengthening procedures of 5 mm were applied once monthly for 3 months, and, after 4 months, all piglets were euthanized. Histologic sections of the unfused disks and FJ were analyzed, and morphometric histologic analysis was performed. RESULTS: On the basis of the Gries criteria, unfused disk median grades were 1, 2, and 4 for control, SBFI, and IF, respectively, that revealed a statistical difference (P<0.001). Unfused FJ median grades were 1 and 2 for control and SBFI, respectively, that revealed a statistical difference (P<0.001). The mean hypertrophic zone (HZ) heights were 69.78, 84.20, and 66.14 µm; HZ chondrocyte cell widths were 19.03, 18.76, and 17.36 µm; and HZ chondrocyte cell heights were 15.01, 15.04, and 12.42 µm in the CG, SBFI, and IF groups, respectively. Statistically, for HZ heights, SBFI was different compared with CG and IF (P<0.001), and, for HZ chondrocyte cell widths and heights, IF was different compared with CG and SBFI (P<0.001). CONCLUSIONS: Morphometric analysis in this study supports the findings that SBFI preserves the growth potential of the spine. Furthermore, changes in the HZ heights show that distractive forces stimulate the apophyseal growth of the axial skeleton describing how the growth rate of the spine in GR might surpass the normal growth rate. Overall, although some degenerative changes are observed, SBFI and repeated distractions alone are not solely responsible for FJ arthrosis and disk degeneration, given that they are structurally preserved. CLINICAL RELEVANCE: GR and regular lengthening procedures do not impair disk health and preserve the growth potential of the spine if it is applied with a meticulous technique.

Osteotomies/spinal column resection in paediatric deformity.

The spinal deformities in paediatric population differ from those in the adult population. Vertebral osteotomies are indicated when the deformity is too rigid to be corrected either with instrumentation alone or with the addition of soft tissue releases. When surgical intervention is to be carried out, correcting the deformity and ceasing progression should be aimed at as well as allowing further growth and improving pulmonary function. Osteotomies in the spine surgery should aim to achieve an appropriate balance in both sagittal and coronal planes. Varied clinical and radiological scenarios necessitate different osteotomy types. The purpose of this article is to introduce each osteotomy type and discuss their indications, prerequisites and complications. Osteotomy options for correcting spinal deformities are Ponte osteotomy, Smith-Petersen osteotomy, pedicle subtraction osteotomy, bone-disc-bone osteotomy and vertebral column resection. All the osteotomy types are technically demanding. Appropriate selection of the type of the osteotomy depends on the surgeons' experience, type of the deformity, magnitude of the curve, remaining growth potential and operative goals. Neuromonitoring should be an indispensible part of the procedure. Spine osteotomies are effective procedures for the treatment of paediatric spine deformities if experienced surgical team performs them.