Objective:To investigate the risk factors for severe distal curve progression after posterior hemivertebra (HV) resection and short-segment fixation in patients with congenital cervicothoracic scoliosis (CTS), and to analyze the surgical revision strategy.Methods:Imaging and clinical data of patients who underwent posterior HV resection and short-segment fixation for CTS between August 2012 and August 2021 at Nanjing Drum Tower Hospital were retrospectively analyzed. A total of 55 patients were recruited, including 27 females and 28 males with an average age of 8.5±3.6 years (range 3-15 years) at surgery and an average Risser grade of 0.7±1.4 (range 0-4). The number of fused segments averaged 6.9±1.6 (range 4-10), and the mean follow-up was 38.7±18.9 months (range 9-94 months). According to the severity of distal curve progression, the recruited patients were divided into three groups: non-progression group (NPG), mild progression group (MPG), and severe progression group (SPG). The latter two groups were collectively called the progression group (PG). The cervicothoracic Cobb angle, T1 tilt angle, coronal balance distance (CBD), neck tilt angle, clavicular angle, head tilt angle, head shift, and upper (UIV) and lower instrument vertebra (LIV) tilt angle on the standing whole spine X-ray were measured before and after surgery and at the last follow-up. The correction rate of the Cobb angle in the osteotomy area was measured and calculated on CT three-dimensional reconstruction, and the proportion of patients with Klippel-Feil syndrome (KFS) was recorded. Statistical analysis was conducted on the various parameters between the two groups. For factors with statistical significance in the single-factor analysis, binary logistic regression analysis was performed to identify the high-risk factors for distal curve progression.Results:There were 38 cases in the NPG, 11 in the MPG, and 6 in the SPG. Compared to the NPG, the PG showed more severe coronal imbalance preoperatively, with CBD of 35.6±22.3 mm and 11.6±7.1 mm respectively; more severe neck tilt and head shift, with neck tilt angle of 17.4°±8.3° and 12.4°±6.9° respectively, and head shift of 22.8±17.7 mm and 13.9±9.8 mm respectively; and a higher proportion of KFS, 65% (11/17) and 34% (13/38) respectively, all with statistical significance ( P<0.05). Postoperatively, the PG showed more severe coronal imbalance compared with the NPG, with 17.3±12.7 mm and 9.6±8.1 mm respectively; more evident residual deformity, with cervical tilt angles of 9.4°±4.6° and 6.4°±5.3° respectively, and head shift of 14.7±7.4 mm and 9.1±5.9 mm respectively; lower correction of Cobb angle in the apical osteotomy region, with rates of 40.1%±15.2% and 50.3%±19.9% respectively; more significant UIV and LIV tilt, with UIV tilt angles of 14.3°±7.4° and 9.8°±5.3° respectively, and LIV tilt angles of 8.1°±5.5° and 4.5°±3.6° respectively, all with statistical significance ( P<0.05). SPG showed only more severe coronal imbalance preoperatively compared with the MPG, with 50.7±31.3 mm and 27.3±9.6 mm respectively; and head shift, with 33.5±25.0 mm and 16.9±11.0 mm respectively, all with statistical significance ( P<0.05). Logistic regression analysis demonstrated a significant correlation between significant preoperative coronal imbalance and postoperative distal scoliosis progression [ OR=1.299, 95% CI (1.101, 1.531), P=0.002]. Five cases (83.3%) in SPG underwent revision surgery with an average follow-up of 25 months, and selecting the LIV down to the stable region was the major revision strategy. Conclusion:Combined KFS, residual cervicothoracic deformities, and tilting of UIV and LIV are key causes, whereas significant preoperative coronal imbalance is an independent risk factor predisposing to the distal curve progression.

Objective:To compare the clinical outcomes between three-column osteotomy and posterior-column osteotomy for correcting dystrophic kyphoscoliosis secondary to neurofibromatosis type 1 (DKS-NF1).Methods:ALL of 84 patients with DKS-NF1 were retrospectively analyzed, and the average age was 17.7±6.9 years. There were 50 cases with single curve, 18 cases with double curves, and 16 cases with triple curves; kyphosis was found in 42 cases in the thoracic area, 31 cases in the thoracolumbar area, and 11 cases in the lumbar area. The patients were divided into two groups: posterior column osteotomy group and three column osteotomy group based on surgical strategy. The radiographic parameters (including the magnitude of kyphosis, scoliosis, coronal balance distance, etc.) were compared between the two groups before and after surgery, and during the follow-up. The surgical efficacy was also compared based on the spinal correction and complications (such as cerebrospinal fluid leakage, pneumothorax, rod breakage, etc.).Results:The posterior column osteotomy group consisted of 74 patients and the column osteotomy group consisted of 10 patients. The age of patients in the posterior column osteotomy group was significantly younger than that in the three-column osteotomy group (15.8±4.8 years vs. 29.4±10.2 years, t=7.088, P<0.001), and the proportion of preoperative traction in this group was significantly higher than that in the three column osteotomy group (26/74 vs. 0, P=0.027). The apex of kyphosis in the three-column osteotomy group mainly located in the thoracolumbar and lumbar area, significantly higher than that in the posterior column osteotomy group (10/10 vs. 32/74, P=0.001). The magnitude of kyphosis in the two groups were 73.8°±20.9° and 63.1°±21.4° before surgery, respectively ( t=1.506, P=0.136). After surgery, they were corrected to 43.1°±20.9° and 21.1°±22.8°, respectively ( t=3.066, P=0.003), with correction rates of 43.7% ±19.6% and 84.1% ±78.7%, respectively ( t=3.677, P<0.001). At the last follow-up, they were maintained at 46.5°±20.9° and 24.6°±25.5°, respectively ( t=3.016, P=0.003). The Cobb angle of the main curve was corrected from preoperative 83.0°±29.0° and 66.3°±17.7° ( t=1.766, P=0.081) to postoperative 50.6°±20.8° and 40.8°±15.6° ( t=1.436, P=0.155), with correction rates of 38.3% ±16.6% and 39.3% ±12.7% ( t=0.191, P=0.849), respectively. At the last follow-up, they were maintained at 52.3°±20.5° and 43.1°±18.2°, respectively ( t=1.339, P=0.185). The proportion of multi-rod system application and screw density in three column osteotomy group was significantly higher than that in posterior column osteotomy group (8/10 vs. 20/74, P=0.002; 72.0% ±11.3% vs. 61.4% ±14.6%, t=2.173, P=0.033). The incidence of complications in the two groups was 12.2% (posterior column osteotomy group, 9/74) and 20% (three column osteotomy group, 2/10), respectively, with no statistically significant difference ( P=0.613). Conclusion:Three-column osteotomy is mainly used to treat adult kyphosis in DKS-NF1 patients. While the posterior column osteotomy methods were mainly applied in young patients. Most patients can achieve the purpose of deformity correction by posterior column osteotomy alone or combined with anterior complementary fusion. For patients with severe kyphosis, preoperative Halo gravity traction can help to further correct the intraoperative deformities.

Objective:To evaluate the therapeutic efficacy and safety of SRS-Schwab Grade VI osteotomy in the management of severe angular kyphosis and to assess perioperative and postoperative complications.Methods:A comprehensive retrospective analysis was conducted on 19 patients diagnosed with severe angular kyphosis who underwent SRS-Schwab Grade VI osteotomy between June 2011 and June 2021. Various radiographic parameters, including global kyphosis (GK), sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and sacral slope (SS), were quantified through standing radiographs obtained preoperatively, postoperatively, and at the most recent follow-up. Incidences of intraoperative and postoperative complications were meticulously recorded. The Scoliosis Research Society-22 (SRS-22) score was utilized to gauge patient quality of life, while neurological function was appraised using the American Spinal Injury Association (ASIA) grading system.Results:The mean follow-up duration was 24.9±9.5 months, ranging from 12 to 49 months. The intraoperative blood loss averaged 2 995.3±1 357.6 ml, with a mean operative time of 414.5±65.8 minutes. The osteotomy was performed across an average of 2.4±0.6 segments, with 11.0±1.7 segments subsequently fused. Statistically significant alterations were observed in multiple parameters including GK ( F=658.56, P<0.001), SVA ( F=18.86, P<0.001), LL ( F=180.73, P<0.001), TK ( F=166.12, P<0.001), PT ( F=14.68, P<0.001), and SS ( F=6.03, P=0.005) when compared at preoperative, immediate postoperative, and ultimate follow-up intervals. PI remained statistically invariable ( F=0.29, P=0.750). Preoperative mean values for GK and SVA were 107.4°±9.1° and 38.4±19.7 mm, respectively. Postoperatively, GK was dramatically reduced to 39.7°±12.1° ( t=25.59, P<0.001), reflecting a correction rate of 63.2%±10.1%. Concurrently, SVA was markedly improved to 18.1±10.6 mm ( t=4.22, P=0.001). Notably, the correction remained stable during subsequent follow-ups. Functional and self-image domain scores exhibited a significant elevation at the final follow-up in comparison to preoperative values. Seven patients experienced intraoperative neurophysiological monitoring events, but no enduring neurological deficits were discerned postoperatively. A singular case of postoperative neurological impairment was attributed to spinal cord hematoma. Moreover, proximal junctional kyphosis (PJK) manifested in six patients during follow-up, while implant failure was conspicuously absent. Conclusion:SRS-Schwab Grade VI osteotomy demonstrates a commendable efficacy in the correction of severe angular kyphosis, with the resultant alignment proving to be durably maintained throughout the follow-up period.

Objective:To analyze the radiographic improvements after Halo-gravity traction in severe kyphoscoliosis patientswith type III spinal cord on preoperative apex MRI, and to assess the clinical outcomes and surgical safety of Halo-gravity traction in this cohort.Methods:A total of 47 severe thoracic kyphoscoliosis patients with type III spinal cord on preoperative apex MRI who underwent preoperative Halo-gravity traction followed by one-stage posterior spinal fusion from February 2019 to June 2021 in the Nanjing Drum Tower Hospital were retrospectively analyzed. There were 18 males and 29 females with an average age of 22.5±12.8 years (range, 9-60 years). The average duration of traction was 7.4±3.9 weeks (range, 4-16 weeks). Radiographic parameters were measured including the coronal Cobb angle, distance between C 7 plumb line and center sacral vertical line (C 7PL-CSVL), sagittalglobal kyphosis (GK) and sagittal vertical axis (SVA) atpre-traction, post-traction and post-operation, respectively. The traction correction rate was measured as "traction degree before traction-traction degree after traction)/traction degree before traction" and the surgical correction rate was represented as "traction degree before traction-postoperative degree)/ traction degree before traction". The Frankel scoring system was used for the evaluation of neurological status at pre-traction, post-traction and post-operation. Results:All of 47 patients underwent the Halo-gravity traction and posterior spinal correction surgery. The C 7PL-CSVL was 35.7±16.9 mm at initial visit. At post-operation, C 7PL-CSVL was improved to 22.0±13.7 mm ( t=13.75, P<0.001), and the improvement rate was 39.9%±15.5%. The GK was 110.9°±22.1° at initial visit, which was improved to 84.1°±19.9° ( t=8.84, P<0.001) after Halo-gravity traction with an average correction of 23.7%±8.9%. At post-operation, GK was improved to 65.3°±19.3° ( t=10.63, P<0.001), and the improvement rate were 40.1%±20.7%. The SVA was 43.8±19.5 mm at initial visit. At post-operation, SVA was improved to 21.1±14.9 mm ( t=10.32, P<0.001), and the improvement rate were 53.1%±27.0%. A total of 14 patients showed neurological deficits of lower limbs at pre-traction, of which 8 patients had significant neurological improvement after Halo gravity traction; 3 patients had significant neurological improvement after surgery, and the remaining 3 patients had no significant neurological improvement during treatment. No new neurological deficits were observed after Halo-gravity traction or surgery. Conclusion:For severe kyphoscoliosis patients with type III spinal cord on preoperative apex MRI, the Halo-gravity traction could effectively correct the deformity, improve neurological function, enhance the tolerance of spinal cord to surgery and reduce the risk of intraoperative iatrogenic neurological deficit.

Objective:To evaluate whether pelvic fixation is needed in patients undergoing posterior lumbosacral hemivertebra (LSHV) resection and long fusion.Methods:All 32 adult spinal deformity patients with posterior hemivertebra (HV) resection and long segment fixation treated from April 2005 to August 2019 were analyzed retrospectively, including 12 males and 20 females with a mean age of 32.9±8.8 years. According to the state of coronal balance distance (CBD), there were 15 cases of type A (preoperative CBD≤ 30 mm), 1 case of type B (preoperative CBD>30 mm and C 7 plumb line offset to the concave side), and 16 cases of type C (preoperative CBD>30 mm and C 7 plumb line offset to the convex side). The clinical and imaging data before operation, immediately after operation and at the last follow-up were collected, and the short-term and long-term complications related to operation were recorded. The improvement of Cobb angle and coronal balance of primary curve and compensatory curve were evaluated on the whole spine frontal and lateral X-ray films, and the change of coronal balance type after operation was evaluated. According to the mode of distal internal fixation, the patients were divided into two groups: PF group (pelvic fixation): distal fixation to iliac or sacroiliac; NPF group (non-pelvic fixation): distal fixation to L 5 or S 1. Results:All 32 patients were followed up with an average time of 3.9±2.6 years (range 2-11 years). The Cobb angle of primary curve in PF and NPF groups were 42.6°±13.5° and 41.3°±10.9° respectively before operation, and corrected to 13.1°±5.4° and 17.7°±5.8° respectively after operation. It maintained at 13.4°±5.1°and 18.5°±6.7° in the two groups at the last follow-up, respectively ( FPF=32.58, FNPF=28.64, P<0.001). The correction rates were 69.3%±11.8% and 57.6%±10.3%, respectively ( t=2.14, P=0.012). The compensatory curves of in the two groups were corrected from 54.9°±14.8° and 46.8°±13.6° before operation to 17.3°±9.6° and 15.4°±8.4° after operation. It also maintained at 18.5°±8.8°and 17.6°±9.5° in the two groups at the last follow-up, respectively ( FPF=42.97, FNPF=38.56, P<0.001). The correction rates were 68.4%±16.7% and 67.2%±14.9%, respectively ( t=0.17, P=0.849) in the two groups. In PF group, the primary and compensatory curve were similar (69.3%±11.8% vs. 68.4%±16.7%, t=0.15, P=0.837), while the correction rate of compensatory curve in NPF group was significantly higher than that of the primary curve (67.2%±14.9% vs. 57.6%±10.3%, t=2.13, P=0.013). Coronal decompensation occurred in 12 patients (12/32, 37.5%). The CBD in PF and NPF groups was corrected from 33.3±11.2 mm and 28.8±8.1 mm preoperatively to 18.5±3.5 mm and 27.1±6.8 mm postoperatively, respectively, and it showed no significant change at the last follow-up ( FPF=41.61, P<0.001; FNPF=0.38, P=0.896). While the CBD in PF group was significantly better than that in NPF group ( t=3.23, P=0.002; t=2.94, P=0.008). The incidence of coronal decompensation in PF group was 0%, which was significantly lower than 50% (12/24) in NPF group (χ 2=6.40, P=0.014). In addition, 6 cases in PF group were type C coronal decompensation before operation, and the coronal balance was corrected to type A after surgery (100%). Among 10 patients with type C coronal decompensation in NFP, 4 (40%) patients returned to type A after operation, and the difference was statistically significant (6/6 vs. 4/10, χ 2=5.76, P=0.034). Conclusion:Coronal decompensation (12/32, 37.5%) is not rare in patients after posterior LSHV resection and long fusion. Attention should be paid to the match of the corrections between lumbosacral deformity and compensatory curve, which is of great significance in coronal balance reconstruction. Pelvic fixation is helpful to reduce the incidence of postoperative coronal decompensation, especially for the type C patients.

Objective:To evaluate the radiographic and clinical outcomes of pre-operative Halo-gravity traction (HGT) and posterior correction surgery in treating patients with neurological deficits secondary to severe focal angular kyphosis of the upper thoracic spine.Methods:A total of 16 patients (11 males, 5 females) with neurologic deficits secondary to severe focal angular kyphosis of the upper thoracic spine undergoing preoperative HGT and posterior correction operation from January 2010 to December 2019 were retrospectively analyzed. The average age was 12.9±5.6 years (range 6-27 years). The standing X-ray of whole spine was taken at pre-, post-traction and post-operation. The Cobb angles of main curve at both sagittal and coronal planes were measured accordingly. The neurologic function at pre-traction, post-traction and post-operation was assessed according to the American Spinal Injury Association (ASIA) grading. The complications during HGT, operation and post-operative follow-up were recorded for each patient.Results:The average values of focal kyphosis and scoliosis were 96.1°±16.0° (71°-128°) and 75.5°±20.5° (40°-107°) at pre-traction respectively. The spinal cord function graded by ASIA criteria at pre-traction was B in 1 patient, C in 6 and D in 9, respectively. The correction rates of focal kyphosis and scoliosis were 32.8%±15.0% (18.0%-65.9%) and 22.9%±8.0% (14.1%-38.6%) after traction, which were further improved to 45.4%±14.9% (29.0%-69.0%) and 33.6%±8.6% (23.3%-49.3%) at post-operation without significant correction loss during 35.6±14.2 (24-72) months follow-up. After traction, the spinal cord function improved to grade D in 4 patients and grade E in 12 patients. At the last follow-up, the spinal cord functions were grade E in 15 patients and grade C in 1 patient. No neurologic monitor events occurred during operation. One patient suffered from transient left brachial plexus after operation. Further, proximal hook loosening was observed in 2 patients during follow-up. The spinal cord function was ASIA grade C pre-operatively in one patient, who recovered to ASIA grade E after operation and significantly deteriorated to ASIA C at 4 years follow-up.Conclusion:The correction of spinal kyphoscoliosis was satisfactory in this cohort. Preoperative HGT followed by posterior spinal correction surgery is an effective and safe procedure in treating neurological deficits secondary to focal angular kyphosis in the upper thoracic spine.

Objective:To evaluate the safety and efficacy of one-stage posterior-only jumping hemivertebra (HV) resection combined with respective short fusions in the treatment of congenital scoliosis (CS) caused by multiple HVs.Methods:All of 13 consecutive patients with multiple HVs treated surgically from January 2010 to December 2017 were retrospectively reviewed, including 4 males and 9 females with a mean age of 3.7±1.2 years. One child had 4 HVs, and the rest had 2 HVs. The responsible HVs causing local scoliosis/kyphosis deformity or coronal plane deviation were selected as the target of resection. The distal HV was removed firstly and then the proximal one was resected; both of the fixation vertebraes were horizontalized during surgery. The clinical and imaging data of the children before the initial operation, immediately after the operation and at the latest follow-up were collected, and the short-term and long-term complications related to surgery were recorded. The data were evaluated on the whole-standing spine anteroposterior and lateral films, including the corrections of proximal and distal main curves, coronal balance, local kyphosis, and the improvement of spinal growth height (upper and lower internal fixation length, T 1-S 1 length). At the same time, the re-progression of coronal and sagittal deformities of the spine during growth was recorded (coronal decompensation: emerging postoperative curve progression more than 20°; kyphosis progression: kyphosis aggravation between upper and lower internal fixation more than 40°) and internal-fixation-related complications (screw cutting, screw malposition) were recorded. Results:Dual HVs were resected in each child, of which 8 (61.5%) were located on contralateral side of the spine, and 5 (38.5%) were located on ipsilateral side of the spine. The follow-up time was 6.2±3.3 years (range 2.0-10.5 years) after surgery. The Cobb angles of proximal and distal main curves were 36.7°±11.8° and 35.2°±7.8° respectively before surgery and were corrected to 9.7°±6.6° and 6.1°±4.1° respectively after surgery ( F=31.249, F=93.83, P< 0.001) ( t=6.888, t=10.954, P<0.001), and the correction rates was 73.6%±19.6% and 82.7%±11.7%, respectively. They were maintained at 14.3°±5.4° and 8.0°±4.6° at the latest follow-up, showing the correction rates loss of 15.8%±26.9% and 6.9%±7%, respectively. The coronal balance improved from 17.2±14.8 mm pre-operatively to -0.2±15.7 mm postoperatively ( t=2.703, P=0.008), and it remained at 0±18.4 mm at the final follow-up ( F=4.137, P=0.024). The T 1-S 1 length was corrected to 273.8±27.3 mm postoperatively, slightly increased compared with pre-operation 256.3±24.0 mm, ( t=0.680, P=0.527), and significantly increased to 333.2±33.4 mm at the latest follow-up ( t=2.986, P<0.001; F=6.704, P=0.003). Seven patients had local kyphosis before operation, which was significantly improved from 32.2°±13.6° to 6.1°±9.8° with a correction rate of 93.4%±27.0% after surgery ( t=3.355, P=0.004), which showed no significant loss of correction at the latest follow-up (5.4°±10.4°) ( F=11.187, P=0.002). Six patients (46.2%) developed coronal decompensation (Curve magnitude >20 °), with an average of 21.7°±1.9°. Two cases (15.4%) had progressive kyphosis between the thoracic regional internal fixations at 3 months after surgery, which were 68° and 58° respectively. After bracing, both coronal decompensation and sagittal kyphosis were improved. At the last follow-up, the coronal decompensation was improved to 14.7±8.9° and the kyphosis was alleviated to 55° and 46°, respectively. Conclusion:Posterior-only skipping hemivertebra resection and short fusion is a safe, effective procedure yielding significantly improvement of the growth imbalance and reginal spinal deformities of CS with multiple HVs. The mid-term follow-up results showed that the progress of the scoliosis was common during the growth period, which could be further controlled by supplementary brace treatment.

Objective:To compare the incidence of intraoperative neurological complications during correction surgery of spinal deformities in patients with or without rotatory subluxation (RS), and to analyze the correlation between RS and intraoperative neurological complications.Methods:From January 2012 to August 2017, a total of 37 patients with RS undergoing correction surgery, whom was excluded with preoperative spinal traction or three-column osteotomy during operation were retrospectively reviewedin our hospital. Thirty-seven patients without RS undergoing correction surgery were included asthe control group. The radiographic parameters included Cobb angle of main curve, coronal trunk balance (CTB) which was the distance between C 7 plumb line and center sacral vertical line, global kyphosis (GK), sagittal vertical axis (SVA), RS at coronal plane (CRS), RS at sagittal plane (SRS) and axial rotation (AR). The abnormal intraoperative neurophysiological monitoring events and positive wake-up test were recorded. Results:The mean age was 42.4±17.9 years (12-74 years) in the RS group and 42.7±18.3 years (12-74 years) in the control group( t=0.0713, P=0.943). The mean preoperative Cobb angle of main curve, CTB, GK, and SVA was 75.4°±29.7°, 38.4±28.4 mm, 52.8°±25.2°, and 40.3±36.8 mm respectively in the RS group, which was 75.1°±27.6°( t=0.045, P=0.964), 34.8±24.4 mm( t=0.584, P=0.560), 49.8°±22.5°( t=0.540, P=0.591), and 38.7±25.3 mm ( t=0.219, P=0.828) respectively in the control group. There was no significant difference between the two groups among the above preoperative index. Significant improvements in Cobb angle of main curve, CTB, GK, SVA,CRS, SRS and ARA were found between preoperation and postoperation ( P<0.05 for all), while no significant correction loss was observed during follow-up ( P>0.05 for all). There were 6 patients (16.2%) in the RS group and 4 patients (10.8%) in the control group with preoperative neurological deficit of Frankel grade D ( F=0.463, P=0.496). The abnormal intraoperative neurophysiological monitoring events were observed in 5 patients (13.5%) of the RS group and 1 patient (2.7%) of the control group ( F=2.902, P=0.088). Positive wake-up test was found in 2 patients of RS group (5.4%) ( F=2.056, P=0.493). Conclusion:Patients with RS had higher risks of preoperative neurological deficit, abnormal intraoperative neurophysiological monitoring events and deteriorative neurological deficit at postoperation. The RS at preoperation may be a risk factor for intraoperative neurological deficit.

Objective: To illustrate the surgical strategy of sequential correction in degenerative lumbar scoliosis (DLS) with type C coronal imbalance, and to evaluate the clinical outcomes and advances of sequential correction technique. Methods: Twelve patients (2 males and 10 females) applying sequential correction technique from January 2015 to August 2017 were retrospectively reviewed. The ages of the cohort ranged 48-74 years and the average value was 52.3±8.4 years. The sequential correction technique was mainly applied in 3 steps: correction of local kyphoscoliosis with satellite rod on convex side of lumbar spine; correction of lumbosacral curve with L ₄-S₁ Intervertebral fusion and satellite rod on convex side of lumbosacral spine; correction of global deformity with bilateral long rods. The coronal parameters including Cobb angle and distance between C₇ plumb line and center sacral vertical line (C₇PL-CSVL), and the sagittal parameters including global kyphosis (GK) and sagittal vertical axis (SVA) were assessed at pre-operation, post-operationand last follow-up. The quality of life was evaluated using SF-36 questionnaire, and paired t test was used for the statistical analysis. Results: The average follow-up period was 16.7±4.8 months. The Cobb angles at pre-operation and post-operation were 59.6°±18.7° and 25.6°±12.4° (t=3.705, P<0.001), respectively. At last follow-up, the average Cobb angle was 27.5°±13.0°, and there was no significant loss of correction (t=0.366, P=0.718). Post-operative C₇PL-CSVL changed from 48.5±17.2 mm to 9.7±4.3 mm (t=5.842, P<0.001), of which the average value was 10.1±4.5 mm at last follow-up (t=0.223, P=0.826). At post-operation, 11 patients were with type A coronal imbalance, and 1 patient was still with type C coronal imbalance. The scores of bodily pain, general health, and social functioning were 8.4±1.9, 78.1±9.4 and 76.7±8.4 at pre-operation, 10.2±2.0 (t=2.260, P=0.034) , 89.5±7.6 (t=3.267, P=0.004) and 84.5±9.3 (t=2.156, P=0.042) at post-operation. In addition, there was no implant-related complications during follow-up. Conclusion The sequential correction technique could be well used in adult degenerative lumbar scoliosis patients with type C coronal imbalance, which can simplify the surgical procedure, decrease the rates of post-operative coronal imbalance, and obtain rigid internal fixation.

Objective: To evaluate the radiographic and clinical outcomes of Scoliosis Research Society(SRS)-Schwab Grade IV osteotomy in type I congenital kyphosis. Methods: All of 28 patients with type I congenital kyphosis who underwent SRS-Schwab Grade 4 osteotomy from June 2015 to June 2017 were retrospectively reviewed,including 21 males and 7 females aged 10 to 28 years old, with an average of 13.6±8.5 years. On standing wholespinal X-rays at pre-operation, post-operation and each follow-up, global kyphosis(GK), thoracic kyphosis(TK), lumbar lordosis(LL) and sagittal vertical axis(SVA) were measured. The intra-operative and post-operative complications were recorded for each patient. The Scoliosis Research Society-22 questionnaires(SRS-22) and visual analog scale(VAS) for back pain were collected from patients elder than 12 years old at pre-operation and last follow-up. The comparison analysiswasperformed by paired samples t test. Results: At pre-operation, the GK, TK, LL and SVA were 47.0°±4.9°, 16.8°±3.7°, 36.6°±7.7°, (-31.9±13.6) mm, respectively. At 3 months post-operation, the average values improved to 3.7°±2.3°, 36.8°±4.0°, 46.5°±4.4°, 4.0±19.1 mm, respectively. Significant differences were found in all parametersbetween pre- and post-operation. The post-operative follow-up was 12 to 24 months, with an average of 13.2±5.2 months. At the last follow-up, the GK, TK, LL and SVA were 4.0°±2.4°, 38.0°±6.0°, 45.9°±5.4°, 7.6±15.3 mm, and no significant correction loss was found during follow-up. The scores of each domain of SRS-22 questionnaire improved at different level during follow-up, of which the improvement in self-imagewas statistically significant (P<0.001). The scores of VAS for back pain improved significantly after operation (P<0.001). One patient hadabnormal intra-operative monitoringwhile no neurological defectwas detected at post-opera tion. Proximal junctional kyphosis occurred in 2 patients at 3 months follow-up while no patients needed revision surgery. There wereno implant-related complicationsduring follow-up. Conclusion The SRS-Schwab Grade 4 osteotomycould provide satisfying correction with relatively low rates of complications in type I congenital kyphosis. Thus, the SRS-Schwab Grade IV osteotomy is a safe strategy for type I congenital kyphosis.