Compensatory Lumbar Curve Research Articles

Prediction of post-operative adding-on or compensatory lumbar curve correction after anterior vertebral body tethering.

Anterior Vertebral Body Tethering (AVBT), a fusionless surgical technique based on growth modulation, aims to correct pediatric scoliosis over time. However, medium-term curvature changes of the non-instrumented distal lumbar curve remains difficult to predict. The objective was to biomechanically analyze the level below the LIV to evaluate whether adding-on or compensatory lumbar curve after AVBT can be predicted by intervertebral disc (ID) wedging and force asymmetry. 33 retrospective scoliotic cases instrumented with AVBT were used to computationally simulate their surgery and 2-year post-operative growth modulation using a finite element model. The cohort was divided into two subgroups according to the lumbar curvature evolution over 2years: (1) correction > 10° (C); (2) maintaining ± 10° (M). The lumbar Cobb angle and residual ID wedging angle under LIV were measured. Simulated pressures and moments at the superior endplate of LIV + 1 were post-processed. These parameters were correlated at 2years postoperatively. On average, the LIV + 1 simulated moment was 538Nmm for subgroup C, 155Nmm for subgroup M with lumbar Cobb angle > 20° and 34Nmm for angle < 20° whereas the ID angle was 1° for C and 0° for M. On average, a positive moment on the LIV + 1 superior growth plate led to correction of the lumbar curvature, whereas a null moment kept it stable, and a parallel immediate postoperative ID under LIV contributed to its correction or preservation. Nevertheless, the significant interindividual variability suggested that other parameters are involved in the distal non-instrumented curvature evolution. IV.

Treatment for an Adult Patient with Slowly Progressive Idiopathic Scoliosis Using a Unique Anterior Scoliosis Correction Technique: A Case Report

Adolescent idiopathic scoliosis (AIS) can continue to progress after skeletal maturity. Once the progression is severe, posterior spinal fusion (PSF) is the gold standard for surgical treatment. While effective in achieving curve correction, PSF is associated with many problems, including loss of spinal flexibility, uncorrected sagittal deformity, and adjacent segment disease. We present a case of a 50-year-old woman with a documented 38º thoracic curve as a late teen who experienced curve progression after skeletal maturity to &gt;70 ° and underwent Anterior Scoliosis Correction (ASC), a motion-preserving scoliosis correction surgery. Her progressive curve improved from 71º Lenke 1A main thoracic curve to 28°, with a 59% correction being maintained within 5° (33°) at 7 years. She also obtained a 50% correction of her compensatory lumbar curve and correction of hypokyphosis from 2.4° to 23° at 7 years. Along with improvement of her thoracic kyphosis, her lumbar lordosis decreased to a normal range of 60° from 70°, giving her better overall alignment. This case report suggests that motion preserving surgical treatment may be considered for some select adult patients with progressive scoliosis. Key Words: Progressive Scoliosis, Anterior Scoliosis Correction

Clinical, radiological and HRQoL outcomes after selective thoracic fusion with minimum 15-year follow-up.

The purpose of the study was to provide a 15-year natural history evaluation of the radiographic appearance of uninstrumented compensatory lumbar curves in patients who had undergone selective thoracic fusion (STF) for scoliosis, measure any changes in health-related quality of life scores (HRQoL) and compare them with controls matched for age, gender and body-mass index (BMI). STF group included 43 female adolescent idiopathic scoliosis (AIS) patients who underwent STF with mean age 33(27-42) years and a mean follow-up of 18.7 (15-28) years, mean BMI 22(18-29). Preop, early postop and follow-up radiographs were reviewed for behavior of lumbar curves. Control group included a random selection of healthy volunteers with no history of back pain and with mean age 33(27-41), and mean BMI 22(17-33). HRQoL scores were compared between two groups in latest f/up. Radiographs including low dose biplanar imaging with EOS were used to measure disc heights and assess for radiographic evidence of degenerative changes. Various parameters were statistically compared. Posterior fusion was performed in all 43, with all pedicle screws used in 41 and all-hook constructs in 2. Main thoracic curve correction was improved from pre-op to early-post-op and maintained at latest f/up (55.6°-16.1°-16.9°). Spontaneous lumbar curve correction (SLCC) was also maintained beyond 15years (39.9°-16.6°-17.1°). Two patients developed coronal decompensation following surgery, but improved with time and were well compensated at final follow-up. Mean HRQoL scores, self-image and mental health scores were higher in STF group than control group (p < 0.05). SRS-22r pain and function, Oswestry Disability Index and Numeric Rating Scale, marital status, number of children were similar between the groups(p > 0.05). All disc heights except L5-S1 were significantly lower in STF group (p < 0.05). There was no significant difference between the groups for degenerative changes in the latest radiographs. In this group of patients, the uninstrumented lumbar curve spontaneously corrected and the correction was maintained after 18years following surgery using STF. Mild degenerative changes were seen radiographically and HRQoL scores suggest that the psychological-functional well-being are quite good in the long term in AIS patients who have undergone STF when compared with an age-gender-BMI-matched population.

Risk of early complication following anterior vertebral body tethering for idiopathic scoliosis.

The purpose of this study was to determine peri-operative morbidity associated with anterior vertebral body tethering (aVBT) for idiopathic scoliosis. Of 175 patients treated with aVBT, 120 patients had 2year follow up and were included in this study. Prospectively collected clinical and radiographic data was analyzed retrospectively. Pre-operatively, the mean patient age was 12.6year (8.2-15.7year), Risser 0-3, with main thoracic scoliosis 51.2° (40-70°). Immediately post-operative, scoliosis improved to 26.9° (6-53°; p < 0.05), at 1-year post-operative was 23.0° (- 11 to 50°; p < 0.01 vs immediate post-op) and at 2-year post-operative was 27.5° (- 5 to 52; p = 0.64 vs immediate post-op). Pre-operative T5-T12 kyphosis was 16.0° (- 23 to 52°), post-operative was 16.9° (- 7 to 44°), at 1-year was 17.5° (- 14 to 61°) and at 2-year was 17.0° (- 10 to 50°; p = 0.72 vs pre-op). All patients underwent thoracoscopic approach, EBL 200ml (20-900ml), surgical time 215.3min (111-472min), anesthesia time 303.5min (207-480min), ICU stay of 0.2day (0-2days), and post-operative hospital stay 4.5days (2-9days). During the in-hospital peri-operative period, there were no unplanned return to the operating room (UPROR) and there was a 0.8% rate of complication: one pneumothorax requiring reinsertion of chest tube. By 90days post-operative, there was no UPROR and a 5% rate of complication. Five additional patients developed complications after discharge: one CSF leak treated with blood patch injection in the clinic and resolved, two pleural effusions requiring chest tubes, one superficial wound infection and one pneumonia treated with outpatient antibiotics. By 1-year post-op, there was a 1.7% rate of UPROR and 8.3% rate of complication. Four additional patients developed complications beyond 90days: two upper limb paresthesia required outpatient medical management, one CSF leak which initially treated blood patch injection in the clinic initially which then required UPROR, and one compensatory lumbar curve add on that was treated with extension of the tether. By 2-years post-op, there was a 6.7% rate of UPROR and 15.8% rate of complication. 9 additional complications developed after 1year. One curve progression, one keloid scar, one right leg weakness, 4 cable failures and 2 curve overcorrections. This large, multicenter series of aVBT demonstrated a 15.8% complication rate and a 6.7% UPROR rate at 2year post-operatively. This early study during the learning curve of aVBT found higher rates of CSF leaks and overall complications than would be expected for PSFI at 1year post-operatively and a higher rate of overall complications and of UPROR than would be expected for PSFI at 2year post-operatively. As is common with new procedures, the complication rate may fall with further experience.

295. Should selective thoracic fusion be reserved for nonstructural compensatory lumbar curves? Radiographic and clinical results from propensity score matched patients at minimum 5-year follow-up

BACKGROUND CONTEXT For adolescent idiopathic scoliosis (AIS) Lenke Type 1-4C curves, controversy exists whether selective thoracic fusion (STF) is sufficient or non-selective fusion (NSF) should be used to treat the associated lumbar curves. PURPOSE In this multicenter study with minimum 5-year follow-up, we performed propensity score matching to compare patients treated with selective thoracic fusion and non-selective fusion for Lenke 1-2C curves vs 3-4C curves. STUDY DESIGN/SETTING Retrospective analysis of multicenter, prospectively collected data using propensity score matching PATIENT SAMPLE A total of 74 patients with Type 1-2C curves and 36 patients with 3-4C curves OUTCOME MEASURES Radiographic parameters (such as main thoracic and compensatory lumbar Cobb angles) and SRS-22 scores METHODS A prospective, multicenter database was queried for Lenke 1-4C curves (min 5-yr follow up). Patients were dichotomized to STF (fusion L1 or above) vs NSF (fusion below L1). We analyzed two subgroups: 1) non-structural lumbar curves (1-2C), and 2) structural lumbar curves (3-4C). After propensity score matching within each subgroup for age and preop thoracic and lumbar Cobb angles, we conducted within and between group comparisons of radiographic data and SRS-22 scores. RESULTS Of 124 patients with 1-2C curves, 74 matched (37 STF, 37 NSF). At 5 years postop, both STF and NSF led to improvement in main thoracic (MT) and compensatory lumbar (CL) Cobb angles as well as coronal balance (C7-CSVL), but NSF values were better than STF (p CONCLUSIONS In propensity score matched patients treated for Lenke Type 1-2C curves, STF results in slightly less radiographic correction but similar patient reported outcomes as NSF at 5 years. In contrast, matched patients treated for Lenke Type 3-4C curves with NSF have both better radiographic and patient reported outcomes when compared to STF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Multilevel noncontiguous spinal fractures in adolescent idiopathic scoliosis: A report of three cases

This is a report of three cases of patients with Adolescent Idiopathic Scoliosis who presented with multilevel noncontiguous fractures of the spine. Interestingly, the apical vertebrae of the scoliotic curve were involved in all these three cases. The first patient had a fracture at apical T7 of the main thoracic curve and a fracture dislocation at apical L1 at the compensatory lumbar curve. In the second patient, the fractures occurred at the apex of a lumbar major curve and the compensatory main thoracic curve at L2 and T8, respectively. In the third patient, one of the four fractures occurred over the apex of thoracic curve at T8. Therefore, when a patient with idiopathic scoliosis presents following a high-energy accident, a higher index of suspicion should be maintained to diagnose multilevel fractures, especially over the apical vertebrae. Minimally Invasive Stabilization technique is useful in the stabilization of multilevel noncontiguous spinal fractures in these patients.

Long-term Results of Spine Stapling for AIS to Skeletal Maturity and Beyond.

We looked at long-term follow-up of spine stapling with Nitinol Staples. This was a cohort of all adolescent idiopathic scoliosis (AIS) patients with curves at high risk to progress based on curve magnitude, premenarchal status in all females, failure of brace treatment, and skeletal immaturity. This is a single surgeon retrospective review of consecutive AIS patients treated with Nitinol staples for progressive scoliosis. Fourteen patients, 16 curves from 2005 to 2008 were eligible. Minimum curve for stapling was 30 degrees. Standard preoperative, intraoperative, and postoperative data were collected. All patients were followed for a minimum of 36 months and to skeletal maturity. Three groups were: improved (group 1), correction of any amount; minimal progression (group 2), progression ≤10 degrees; and failure (group 3), ≥10 degrees of progression. A total of 13 thoracic curves and 2 compensatory lumbar curves met the inclusion criteria (94%). Average follow-up was 61 months. The mean preoperative main thoracic curve was 35 degrees. All but 1 patients progressed at least 9 degrees in a brace prior to stapling. Females were all premenarchal, 10 patients were Risser 0 and 3 Risser 1. The average number of vertebrae stapled per curve was 6. Group 1 included 6 curves (40%). Group 2, 5 curves (33%). Group 3, 4 curves (27%). Three patients went on to uncomplicated fusion. Final curve measurement at the end of follow-up or before fusion (P=0.0037), curve progression (P≤0.001), and percentage of coronal correction on first postoperative standing radiograph (P=0.042) were the significant differences between groups 1+2 (successful) versus group 3 (failures). In total, 73% of this group either progressed ≤10 degrees or improved. This is the first study that follows AIS patients treated with spine stapling to skeletal maturity. Staples likely changed natural history in some of our patients. Initial percentage of correction on first standing postoperative PA x-rays was the only predictor of success. Stapling was safe without any long-term complications. Level III-retrospective study.

Long-term Outcome of Selective Thoracic Fusion Using Rod Derotation and Direct Vertebral Rotation in the Treatment of Thoracic Adolescent Idiopathic Scoliosis: More Than 10-Year Follow-up Data.

This was a retrospective comparative study. To evaluate long-term outcomes of selective thoracic fusion (STF) using both rod derotation (RD) and direct vertebral rotation (DVR) with pedicle screw instrumentation (PSI) in the treatment of thoracic adolescent idiopathic scoliosis (AIS) with a minimum 10-year follow-up. Postoperative compensation and maintenance of the unfused lumbar curve after STF is very important factor for the satisfactory results in the treatment of thoracic AIS. Sixty-five patients with thoracic AIS treated with STF from the neutral vertebra (NV) to NV or NV-1 with RD and DVR were retrospectively analyzed with a minimum 10-year follow-up. Patients were divided into 2 groups: satisfactory (n=52) and unsatisfactory groups (n=13). Unsatisfactory results were defined as an adding-on, a lowest instrumented vertebra (LIV) tilt of >10 degrees, or coronal balance >15 mm. No significant differences were observed in the main thoracic curve between the satisfactory and unsatisfactory groups postoperatively (P=0.218) and at the last follow-up (P=0.636). Significant improvements of LIV tilt and disk angle were observed in both groups, but these improvements deteriorated during the follow-up period in the unsatisfactory group. Significant differences of apical vertebra (AV) and end vertebra (EV) were observed postoperatively (AV: P=0.001, EV: P=0.001) and at the last follow-up (AV: P<0.000, EV: P<0.000) between the 2 groups. STF using RD and DVR can achieve satisfactory deformity correction for thoracic AIS with satisfactory compensatory lumbar curve that was maintained over long-term follow-up. Progression of unfused lumbar curve closely related with LIV tilt and disk angle showing insufficient DVR. Therefore, STF with sufficient DVR required to achieve satisfactory deformity correction and prevent a distal adding-on phenomenon in the treatment of thoracic AIS.

The Natural Course of Compensatory Lumbar Curves in Nonoperated Patients With Thoracic Adolescent Idiopathic Scoliosis.

A retrospective, long-term follow-up study. We investigated the natural course of compensatory lumbar curves in patients with primary thoracic adolescent idiopathic scoliosis (AIS). The natural course of compensatory lumbar curves in primary thoracic AIS remains unknown. Inclusion criteria were right-sided primary thoracic AIS ≥30° with a Lenke lumbar modifier of A or B at skeletal maturity and ≥30 years of age at the time of the survey. Fifty-one patients (mean age, 40.2 yr) returned for a follow-up evaluation (follow-up rate, 34.2%). Patients were classified into three groups based on the lumbar modifier (A or B) and direction of L4 tilt [right (R) or left (L)] (AR, n.11; AL, n.18; and B, n.22). At the time of the survey, 42 patients underwent radiological examinations and 37 underwent lumbar magnetic resonance imaging. Quality of life questionnaires were completed in all patients and in a 1:1 matched control group (no history of scoliosis). The thoracic curves had significantly progressed in all patient groups, while the compensatory lumbar curve progressed only in the B group. The C7 translation and L4 tilt shifted to the right in the AR and AL groups, but did not change in the B group. As a result, the L4 tilt (median, 11°) and C7 translation (18.6 mm) tended to be the greatest in the AR group. The incidences of Modic changes at L4/5 discs and ≥3 cm on the visual analogue scale for low back pain were significantly higher in the AR group (77.8% and 54.5%, respectively) compared with that in the other groups. The natural course of compensatory lumbar curves is dependent on the lumbar modifier and direction of L4 tilt. Adolescent patients with right-sided primary thoracic AIS (≥30°) with L4 tilted to the right should be considered for periodic follow-ups into adulthood. 4.

Five-year outcomes of the First Distal Uninstrumented Vertebra after posterior fusion for Adolescent Idiopathic Scoliosis Lenke 1 or 2

BackgroundTilt of the First Distal Uninstrumented Vertebra (FDUV) reflects changes in the main curve and compensatory lumbar curve after posterior fusion to treat thoracic Adolescent Idiopathic Scoliosis (AIS). HypothesisFDUV tilt 5 years or more post-fusion depends chiefly on reduction of the main curve and on other factors such as selection of the last instrumented vertebra. Material and methodA multicenter retrospective cohort of 182 patients with Lenke 1 or 2 AIS treated with posterior instrumentation and followed up for a mean of 8 years and a minimum of 5 years was studied. The patients were divided into two groups based on whether tilt of the upper endplate of the FDUV was ≤5° or >5°at last follow-up. Variables associated with tilt were identified by multiple logistic regression. ResultsSix variables were significantly associated with FDUVtilt: percentage of correction at last follow-up, correction loss, lumbar modifier B, number of instrumented vertebrae, inclusion within the instrumentation of the distal neutral vertebra, and inclusion within the instrumentation of the lowest vertebra intersected by the central sacral vertical line. Discussion and conclusionThe main variables associated with FDUVtilt ≤5° were a final correction percentage ≥60% and absence of correction loss between the postoperative period and last follow-up. Given the stable reduction provided by contemporary instrumentations, we recommend selective thoracic fusion of Lenke 1 or 2 AIS with lumbar modifiers A, B, and C. The lowest instrumented vertebra should be either the neutral vertebra or the vertebra intersected by the central sacral vertical line if it is distal to the neutral vertebra. Level of evidence IVRetrospective multicenter study.

Onset and remodeling of coronal imbalance after selective posterior thoracic fusion for Lenke 1C and 2C adolescent idiopathic scoliosis (a pilot study)

BackgroundPostoperative coronal imbalance is a significant problem after selective thoracic fusion for primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). However, longitudinal studies on postoperative behavior of coronal balance are lacking. This multicenter retrospective study was conducted to analyze factors related to onset and remodeling of postoperative coronal imbalance after posterior thoracic fusion for Lenke 1C and 2C AIS.MethodsTwenty-one Lenke 1C or 2C AIS patients, who underwent posterior thoracic fusion ending at L3 or above, were included with a minimum 2-year follow-up. The mean patients’ age was 15.1 years at the time of surgery. Radiographic measurements were performed on Cobb angles of the main thoracic (MT) and thoracolumbar/lumbar (TLL) curves and coronal balance. Factors related to the onset of immediately postoperative coronal decompensation (IPCD) and postoperative coronal balance remodeling (PCBR), defined as an improvement of coronal balance during postoperative follow-up, were investigated using comparative and correlation analyses.ResultsMean Cobb angles for the MT and TLL curves were 57.3° and 42.3° preoperatively and were corrected to 22.8° and 22.5° at final follow-up, respectively. Mean preoperative coronal balance of −3.8 mm got worse to −21.2 mm postoperatively, and regained to −12.0 mm at final follow-up. Coronal decompensation was observed in two patients preoperatively, in ten patients immediately postoperatively, and in three patients at final follow-up. The preoperative coronal balance and lowest instrumented vertebra (LIV) selection relative to stable vertebra (SV) were significantly different between patients with IPCD and those without. PCBR had significantly negative correlation with immediately postoperative coronal balance.ConclusionsIPCD after posterior thoracic fusion for Lenke 1C and 2C AIS was frequent and associated with preoperative coronal balance and LIV selection. However, most patients with IPCD regained coronal balance through PCBR, which was significantly associated with immediately postoperative coronal balance. A fixation more distal to SV shifted the coronal balance further to the left postoperatively.

Spontaneous derotation of compensatory lumbar curve after thoracic fusion in adolescent idiopathic scoliosis.

Introduction: Currently, excellent three-dimensional correction can be achieved with use of segmental pedicle screw fixation in adolescent idiopathic scoliosis (AIS). In the majority of patients with major thoracic curves, selective thoracic fusion (STF) may be considered to maximize motion segment of the unfused lumbar spine. This study aimed to investigate the extent of spontaneous derotation of the lumbar curve following STF. Methods: AIS patients who underwent STF using posterior pedicle screw fixation were retrospectively reviewed. Angle of vertebral rotation was defined as the difference between the axial rotation angles of the apical vertebra and S1 vertebra on axial CT images. Radiographic measurements included major thoracic curve, thoracolumbar/lumbar curve (preoperative and postoperative), and side-bending curve. The relationships between the axial rotation of the lumbar spine and radiographic measurements were also analyzed. Results: Thirty patients (all females) were included. Preoperative thoracic Cobb measured 62.1±9°, which improved to 20.3±5° at 2 years postoperatively, resulting in 67% correction. Preoperative lumbar Cobb measured 38.0±9°, which spontaneously improved to 19.0±7°, indicating a 50% correction. Preoperatively, the axial rotation of apical lumbar vertebra was 10.2±5.5°, which changed to 7.0±4.8° (32% spontaneous correction). Comparing the correction between the axial rotation of the lumbar spine and other parameters, postoperative angle of axial rotation correlated well with preoperative (r=0.79) and postoperative (r=0.82) lumbar Cobb angle. Meanwhile, the improvement of axial rotation of the lumbar spine correlated with postoperative thoracic curve (r=－0.42), postoperative lumbar curve (r=－0.57), and thoracic apical translation change (r=0.43). Conclusions: In AIS patients with major thoracic curves, spontaneous axial derotation of the lumbar curves occurred with a mean correction rate of 32% after STF. A greater spontaneous derotation of the lumbar curve would be related to correction of the thoracic curve.

The effectiveness of selective thoracic fusion for treating adolescent idiopathic scoliosis: a systematic review protocol.

REVIEW QUESTION / OBJECTIVE The objective of this review is to assess the effectiveness of selective thoracic fusion as a form of treatment in adolescent idiopathic scoliosis. This will be compared with all other forms of operative management for major structural thoracic curves. INCLUSION CRITERIA Types of participants A comprehensive and exhaustive literature search will be conducted for studies that include children aged 10-18 years with adolescent idiopathic scoliosis who have a scoliosis curve with a thoracic component that is described as structural (as described by the Lenke classification). In addition those with congenital, neuromuscular or syndromic causes for their scoliosis or any previous spinal fusion will be excluded. Types of intervention This review will consider studies that evaluate fusion of the thoracic curve with distal fusion no lower than L1. Both anterior and posterior approaches will be included; however any patient who receives both will be excluded. All forms of instrumentation for fusion such as pedicle screws, hooks and rods will be included. This will be compared where possible to any other surgical fusion for a structural thoracic curve. This will include studies that compare selective and non-selective spinal fusion in the same article, or selective spinal fusion only, but not non-selective spinal fusion only. Types of outcomes Primary outcomes include: Functional/Quality of life survey (SRS- 22, SRS-24, SRS-30 or similar). Complication rate – including, but not limited to, adding on, coronal imbalance, junctional kyphosis and re-operation. Respiratory function. Secondary outcomes include: Postoperative main thoracic Cobb angle, and average change in angle. Postoperative compensatory lumbar Cobb angle, and average change in angle. Coronal balance. Sagittal balance. Apical vertebral rotation and change.

Disc and Vertebral Responses in the Unfused Lumbar Curve to Selective Thoracic Fusion in Lenke 1B/1C Scoliosis

Introduction Several previous studies have reported spontaneous lumbar curve correction for both anterior and posterior selective fusion in patients with Lenke 1B or 1C; however, the mechanism for this phenomenon remains unclear. The objective of this study is to analyze the detailed response of compensatory lumbar curve to selective thoracic fusion in patients with adolescent idiopathic scoliosis (AIS) with Lenke 1B/1C curve. Patients and Methods This study included patients with AIS with Lenke type 1B or 1C curves treated with posterior selective thoracic fusion (LIV at L1) from 2006 to 2008 in our institution. They had a major right thoracic curve and a compensatory lumbar curve. They were followed for at least 24 months. Radiographic measurements including disc angle and vertebra tilt in the lumbar region were compared before surgery, after surgery, and at latest follow-up. Results A total of 20 patients (7 boys and 13 girls) with a mean age of 15 years were included in this study. The thoracic curve was corrected from 46 ± 7.2 degrees preoperatively to 8 ± 4.7 degrees postoperatively, and to 9 ± 5.1 degrees at the latest follow-up. The mean lumbar compensatory Cobb angle was 36 ± 6.9 degrees before surgery, spontaneously correcting to 12 ± 5.3 degrees at latest follow-up. The most significant change of vertebral tilt occurred at LIV and the L4 vertebra in the coronal plane. Change in disc angle was 6.4 ± 3.1 degrees at L1/L2, 3.2 ± 2.3 degrees at L2/L3, 1.0 ± 1.3degrees at L3/L4, −2.3 ± 1.9 degrees at L4/L5, and −0.7 ± 0.5degrees at L5/S1. L1/L2 disc ranks highest among all the discs in the contribution to correction of the lumbar curve. Conclusion LIV and the L4 vertebra have a trend to be horizontal after selective thoracic fusion. Spontaneous correction of the unfused lumbar curve relies on the compensatory changes of lumbar disc angle, which are mainly at the junctional disc right below LIV. This study suggests that the disc right below LIV assumes the greatest portion of correction force transmitting therefore is prone to degenerate earlier than normal.

Postoperative behavior of thoracolumbar/lumbar curve and coronal balance after posterior thoracic fusion for Lenke 1C and 2C adolescent idiopathic scoliosis

Background Controversy still exists around surgical strategies for Lenke type 1C and 2C curves with primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). The benefit of selective thoracic fusion (STF) for these curve types is spontaneous lumbar curve correction while saving more mobile lumbar segments. However, a risk of postoperative coronal decompensation after STF has also been reported. This multicenter retrospective study was conducted to evaluate postoperative behavior of thoracolumbar/lumbar (TLL) curve and coronal balance after posterior thoracic fusion for Lenke 1C and 2C AIS.

Postoperative behavior of thoracolumbar/lumbar curve and coronal balance after posterior thoracic fusion for Lenke 1C and 2C adolescent idiopathic scoliosis.

Controversy still exists around surgical strategies for Lenke type 1C and 2C curves with primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). The benefit of selective thoracic fusion (STF) for these curve types is spontaneous lumbar curve correction while saving more mobile lumbar segments. However, a risk of postoperative coronal decompensation after STF has also been reported. This multicenter retrospective study was conducted to evaluate postoperative behavior of thoracolumbar/lumbar (TLL) curve and coronal balance after posterior thoracic fusion for Lenke 1C and 2C AIS. Twenty-four Lenke 1C and 2C AIS patients who underwent posterior thoracic fusion were included. The mean age of patients was 15.7 years old at time of surgery. Constructs used for surgery in all cases were pedicle screw constructs ending at L3 or above. Radiographic measurements were performed on Cobb angles of the main thoracic and TLL curves and coronal balance. Factors related to final Cobb angle of TLL curve and postoperative change of coronal balance were investigated. Mean Cobb angles for main thoracic and TLL curves were 59.0° and 43.9° preoperatively, and were corrected to 21.5° and 22.0° at final follow-up, respectively. Mean coronal balance was -5.6 mm preoperatively and was corrected to -14.6 mm at final follow-up. Final Cobb angle of TLL curve was significantly correlated with immediate postoperative Cobb angle of main thoracic curve and tilt of lowest instrumented vertebra (LIV). Postoperative change of coronal balance was significantly correlated with selection of LIV relative to stable vertebra. Spontaneous correction of TLL curve occurred consistently by correcting the main thoracic curve and making the LIV more horizontal after posterior thoracic fusion for Lenke 1C and 2C AIS. The more distal fixation to stable vertebra resulted in coronal balance shifting more to the left postoperatively.

Lenke 1C and 5C Spinal Deformities Fused Selectively

Multicenter review of prospectively collected data. To analyze the natural history of uninstrumented compensatory curves prospectively during a 5-year postoperative period in patients with selectively fused Lenke type 1C and 5C adolescent idiopathic scoliosis. After a selective fusion for 1C and 5C adolescent idiopathic scoliosis curve types, there is concern that uninstrumented compensatory curves will continue to progress over time. However, to date, there have been no studies using prospectively collected data beyond 2 years to determine the natural history of these uninstrumented compensatory curves. Lenke 1C and 5C adolescent idiopathic scoliosis cases, prospectively collected from a multicenter study were analyzed. All patients underwent a selective fusion (1C only thoracic curve fused; 5C only thoracolumbar/lumbar curve fused). Preoperative, first-erect, 1-year, 2-year, and 5-year postoperative coronal, sagittal, and axial (Perdriolle) radiographical outcomes were compared using repeated measures analysis of variance with Bonferroni post hoc comparisons (P < 0.05). Twenty-four selectively fused Lenke 1C curves and 21 selectively fused Lenke 5C curves were reviewed. Preoperative compensatory curve Cobb angles were 40° ± 6° and 25° ± 9°, respectively. In Lenke 1C curves, the uninstrumented compensatory lumbar curves were corrected by 32% ± 16% at first erect, 44% ± 17% correction at 1 year, 38% ± 15% correction at 2 years, and 39% ± 19% at 5 years. In Lenke 5C curves, the uninstrumented compensatory thoracic curves were corrected by a mean of 37% ± 29% at first erect, 42% ± 29% at 1 year, 37% ± 29% at 2 years, and 30% ± 23% at 5 years. The sagittal and axial measures of the compensatory curves remained stable during the postoperative period. In Lenke 1C and 5C adolescent idiopathic scoliosis deformity patterns fused selectively, the uninstrumented compensatory curves adjust to match the instrumented primary curve and do not seem to progress between 1 and 5 years postoperatively.

Secondary Curve Behavior in Lenke Type 1C Adolescent Idiopathic Scoliosis After Thoracoscopic Selective Anterior Thoracic Fusion

Analysis of a case series of 24 patients with Lenke 1C adolescent idiopathic scoliosis (AIS) receiving selective thoracoscopic anterior scoliosis correction. To report the behavior of the compensatory lumbar curve in a group of patients with Lenke IC AIS after thoracoscopic anterior scoliosis correction and to compare the results of this study with previously published data. Several prior studies have reported spontaneous lumbar curve correction for both anterior and posterior selective fusions in patients with Lenke 1C/King-Moe 2; however, to our knowledge no previous studies have reported outcomes of thoracoscopic anterior correction for this curve type. All patients with AIS with a curve classification of Lenke 1C and a minimum of 24-month follow-up were obtained from a consecutive series of 190 patients with AIS who underwent thoracoscopic anterior instrumented fusion. Cobb angles of the major curve, instrumented levels, compensatory lumbar curve, and T5-T12 kyphosis were recorded, as well as coronal spinal balance, T1 tilt angle, and shoulder balance. All radiographical parameters were measured before surgery and at 2, 6, 12, and 24 months after surgery. Twenty-four female patients with right thoracic curves had a mean thoracic Cobb angle of 53.0° before surgery, decreasing to 24.9° 2 years after surgery. The mean lumbar compensatory Cobb angle was 43.5° before surgery, spontaneously correcting to 25.4° 2 years after surgery, indicating balance between the thoracic and lumbar scoliotic curves. The lumbar correction achieved (41.8%) compares favorably to previous studies. Selective thoracoscopic anterior fusion allows spontaneous lumbar curve correction and achieves coronal balance of main thoracic and compensatory lumbar curves, good cosmesis, and patient satisfaction. Correction and balance are maintained 24 months after surgery.

MULTIMODAL SURGICAL TREATMENT OF SEVERE SCOLIOSIS USING CONCAVE THORACOPLASTY

Objective. To analyze results of multimodal surgical treatment of patients with severe scoliosis involving concave thoracoplasty. Material and Methods. A total of 40 patients aged from 12 to 31 years with spinal deformities of 70-150° were operated on with posterior CD instrumentation combined with elevating thoracoplasty on the concave side of the thorax deformity. Mean follow-up period was 2 years. Dynamics of the respiratory function was studied. Patients underwent X-ray and CT examinations of the spine, and appearance assessment. Results. The mean preoperative Cobb angle of the major thoracic curve was 101° (range: 70-150°), and postoperative - 47°; postoperative correction was 54° (53 %). The loss of correction was not practically registered at the immediate and long-term follow-up. The mean preoperative Cobb angle of the compensatory lumbar curve was 50.5°, and postoperative - 20.6°. The mean thoracic kyphosis was 51° before surgery and 28.7° after surgery. The mean lung vital capacity was 56.3 % before surgery, and 66.5% in 12 months after surgery. Conclusion. Concave thoracoplasty provides increased mobility of the deformity, and improvement of stabilization, cosmetic and functional results of surgical treatment of patients with severe scoliosis. Hir. Pozvonoc. 2012;(2):37-43.

Using Side-bending Radiographs to Determine the Distal Fusion Level in Patients With Single Thoracic Idiopathic Scoliosis Undergoing Posterior Correction With Pedicle Screws

Prospective. To evaluate a strategy to determine the distal fusion level in posterior pedicle screw correction of single thoracic idiopathic scoliosis. No standard method for selecting the lowest instrumented vertebra (LIV) for the correction of thoracic adolescent idiopathic scoliosis with posterior all-pedicle screw instrumentations exists. Thirty-eight patients with single right thoracic (Lenke 1A) adolescent idiopathic scoliosis undergoing posterior pedicle screw fixation were studied. The LIV was determined using guidelines based on preoperative side-bending radiographs. In brief, (1) the whole thoracic Cobb curve should be included in the fusion mass, and the LIV should not be superior to the lower-end vertebra of the Cobb measurement. (2) On the right side-bending radiographs, the LIV should be derotated to neutral in skeletally immature (Risser 0 to 3) patients and the disc immediately below the LIV must open on the left side by at least 5 degrees. (3) On the left side-bending radiographs, the disc immediately below the LIV must be open on the right side by at least 0 degree. The first segment meeting the criteria when proceeding from the lower-end vertebra caudally is chosen as the LIV. Outcomes were based on the standing radiographs. Minimum follow-up was 2 years. The mean preoperative thoracic curve was 48.4±9.2 degrees and 12.6±6.1 degrees at final follow-up, resulting in a mean correction of 74.7%±8.5%. The mean preoperative compensatory lumbar curve of 23.7±7.5 degrees was 6.3±4.8 degrees at final follow-up. A change in lumbar lordosis from -41.2±11.9 degrees preoperatively to -38.2±9.9 degrees at final follow-up occurred. All patients achieved coronal balance and no decompensation or adding-on phenomenon was observed. Compared with the recommended fusion end by the Harrington stable zone method, 86.9% patients were saved 1 or more motion segment. The method described was effective in obtaining satisfactory curve correction, adequate trunk balance, and preservation of motion segments.