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Several studies have reported incidence and risk factors for the development of proximal junctional kyphosis (PJK) in patients with adolescent idiopathic scoliosis (AIS). However, there is little information regarding long-term follow-up after pedicle screw instrumentation (PSI) with rod derotation (RD) and direct vertebral rotation (DVR). Sixty-nine AIS patients who underwent deformity correction using PSI with RD and DVR were retrospectively analyzed in two groups according to the occurrence of PJK, with a minimum five-year follow-up, including a non-PJK group (n = 62) and PJK group (n = 7). Radiological parameters were evaluated at preoperative, postoperative, and last follow-up. Incidence for PJK was 10.1% (7/69 patients), with a mean 9.4-year follow-up period. The thoracolumbar/lumbar curve (TL/L curve) was proportionally higher in the PJK group. The proximal compensatory curve was significantly lower in the PJK group than in the non-PJK group preoperatively (p = 0.027), postoperatively (p = 0.001), and at last follow-up (p = 0.041). The development of PJK was associated with the TL/L curve pattern, lower preoperative proximal compensatory curve, and over-correction of the proximal curve for PSI with RD and DVR. Therefore, careful evaluation of compensatory curves as well as of the main curve is important to prevent the development of PJK in the treatment of AIS.

Pedicle screw instrumentation (PSI) through posterior approach has been the mainstay of deformity correction for adolescent idiopathic scoliosis (AIS). However, changes in the quantity of paraspinal muscles after AIS surgery has remained largely unknown. The aim of this study was to investigate long-term follow-up changes in paraspinal muscle volume in AIS surgery via a posterior approach. Forty-two AIS patients who underwent deformity correction by posterior approach were analyzed through a longitudinal assessment of a cross-sectional area (CSA) in paraspinal muscles with a minimum five-year follow-up. The CSA were measured using axial computed tomography images at the level of the upper endplate L4 by manual tracing. The last follow-up CSA ratio of the psoas major muscle (124.5%) was significantly increased compared to the preoperative CSA ratio (122.0%) (p &lt, 0.005). The last follow-up CSA ratio of the multifidus and erector spine muscles significantly decreased compared to the preoperative CSA ratio (all p &lt, 0.005). The CSA ratio of the erector spine muscle was correlated with the CSA ratio of the psoas major (correlation coefficient = 0.546, p &lt, 0.001). Therefore, minimizing the injury to the erector spine muscle is imperative to maintaining psoas major muscle development in AIS surgery by posterior approach.

OBJECTIVE There have been no reports on the long-term radiographic outcomes of posterior vertebral column resection (PVCR) in patients with congenital scoliosis. The purpose of this study was to evaluate the surgical outcomes and complications after PVCR and its long-term effects on correcting this deformity in children with congenital scoliosis. METHODS The authors retrospectively analyzed the medical records of 45 patients with congenital scoliosis who were younger than 18 years at the time of surgery and who underwent PVCR and fusion with pedicle screw fixation (PSF). The mean age of the patients at the time of surgery was 11.3 years (range 2.4–18.0 years), and the mean length of follow-up was 12.8 years (range 10.1–18.2 years). RESULTS The mean Cobb angle of the main curve was 46.5° before PVCR, 13.7° immediately after PVCR, and 17.6° at the last follow-up. For the compensatory cranial curve, PVCR corrected the preoperative Cobb angle of 21.2° to 9.1° postoperatively and maintained it at 10.9° at the last follow-up. For the compensatory caudal curve, the preoperative Cobb angle of 23.8° improved to 7.7° postoperatively and was 9.8° at the last follow-up. The authors noted 22 complications, and the overall incidence of complications was 48.9%. CONCLUSIONS Posterior vertebral column resection is an effective procedure for managing congenital scoliosis in patients younger than 18 years. Use of PVCR and fusion with PSF for congenital scoliosis achieved rigid fixation and satisfactory deformity correction that was maintained over the long term. However, the authors note that PVCR is a technically demanding procedure and entails risks for major complications and excessive blood loss.

Study DesignRetrospective study.PurposeTo determine the effect and direction of direct vertebral rotation (DVR) in the lowest instrumented vertebra (LIV) on the uninstrumented lumbar curve depending on the lumbar modifier used for the correction of thoracic adolescent idiopathic scoliosis.Overview of LiteratureDVR in the LIV should be implemented in a different direction to obtain better spontaneous lumbar correction depending on the preoperative lumbar spine modifier.MethodsWe retrospectively analyzed 160 patients with thoracic adolescent idiopathic scoliosis treated by pedicle screw instrumentation and rod derotation. Patients who had a distal fusion level between T11 and L1 were divided into two groups: the DVR group versus the No-DVR group. Each group was divided into subgroups depending on the lumbar modifier used: the DVR-A, B, and C groups versus the No-DVR-A, B, and C groups. The DVR-A group was subdivided into two subgroups depending on the direction of screw rotation in the LIV: the DVR-A-O group (opposite direction) and the DVR-A-S group (same direction).ResultsThere were no significant differences in the preoperative curve characteristics between the two groups. The preoperative lumbar curve was corrected in 70% of the patients in the DVR group and in 56% in the No-DVR group. Spontaneous coronal correction of the lumbar curve was better in the DVR-A-S group than that in the No-DVR-A group. However, the DVR-A-O group had the higher incidence of adding-on deformity. The DVR-B and C groups showed better spontaneous correction of lumbar coronal magnitude, apical vertebral translation, and rotation and the LIV tilting.ConclusionsIn lumbar modifiers B and C, screws in the LIV have to be rotated opposite to the direction of the screw rotation of the main thoracic curve; however, in modifier A, the screws have to be rotated in the same direction.

Rationale: Congenital scoliosis due to a hemivertebra creates a wedge-shaped deformity, which progresses and causes severe spinal deformities as an individual grows. The treatment of congenital scoliosis focuses on early diagnosis and appropriate surgical management before the development of severe deformity. Patient concerns: We report the case of a 4-year-old male child with a left thoracolumbar scoliosis of 27° (T10-T12) due to a T11 hemivertebra who was treated by posterior fusion and pedicle screw fixation at the age of 4 years. The implant was removed due to pain secondary to implant prominence after 4 years without definitive revision surgery, which led to significant progression of the scoliosis, to 50°. The indication for posterior vertebral column resection (PVCR) is a congenital spinal deformity with a curve magnitude greater than 30° with fast progression. This includes documented progression of the curve by more than 5° in a 6- month period, failure of conservative treatment, or both. Outcomes: The patient underwent PVCR of the T11 hemivertebra. Nine years after the revision surgery with PVCR, the patient showed satisfactory results and his spine was well balanced. Lessons: This case shows that removal of an implant that was not the only cause of curve progression at a young age may lead to progression of scoliosis and, therefore, should be avoided unless it is absolutely necessary. Conclusion: Congenital scoliosis due to a hemivertebra at a young age could be treated by hemivertebra resection or anterior and posterior epiphysiodesis as definitive surgical treatment. The patient was eventually treated with PVCR, which achieved satisfactory correction without curve progression in a long-term follow-up.

The etiology of congenital scoliosis and its development remains unclear and has not yet been fully identified, even there are theories that congenital scoliosis could be derived from the failure of formation or failure of segmentation, which are etiologically heterogeneous with genetic, epigenetic, and environmental factors contributing to their occurrence. We reported a case of long-term follow-up after posterior vertebral column resection (PVCR) in both identical twins with similar congenital kyphoscoliosis at thoracolumbar levels. Twin I had been noticed by his parents to have asymmetry of his back at age 5 years, but no treatment was given. Twin II was first noticed to have a spinal problem at 11 years of age by his parents. Overtime, spine of both twins became further deviated to the left with kyphosis and was referred to our hospital. Both monozygotic twins were treated by PVCR and satisfactory results were demonstrated at 10-year follow-up. This case is the first report on the surgical treatment with PVCR, almost simultaneously, in both identical twins who had similar congenital vertebral anomalies causing kyphoscoliosis. Both identical twins with congenital kyphoscoliosis had undergone surgical correction by PVCR, anterior support with a mesh cage and posterior fusion using pedicle screws at the age of 14 years and achieved a satisfactory correction and a stable spine without curve progression with 10-year follow-up.

There is controversy regarding the appropriate proximal fusion level for adult degenerative scoliosis. Ideally, the horizontal vertebra is chosen for the upper instrumented vertebra to create a balanced spine. Fusion to T10 is recommended to prevent junctional problems at the proximal adjacent segment. The purpose of this retrospective study was to determine the optimal proximal fusion level for adult degenerative lumbar scoliosis.Fifty-one patients with adult degenerative lumbar scoliosis (mean age 64.6 years) who underwent posterior instrumentation were analyzed after a minimum 2-year follow-up. The average number of levels fused was 5.9 segments (range 3-9) with distal fusion at L5 in 30 patients and S1 in 21 patients. The upper instrumented vertebra (UIV) ranged from T9 to L2. According to the relationship between UIV, horizontal vertebra (HV) and upper end vertebra (UEV), the patients were divided into three groups in the coronal plane: Group HV (UIV = HV or above); Group HV-UEV (UIV = between HV and UEV); and Group UEV (UIV = UEV or below). In the sagittal plane; the patients were divided into Group T9-10 (UIV = T9-10), Group T11-12 and Group L1-2.Proximal adjacent segment disease (ASD) was identified in 13 (25 %) out of 51 patients, including junctional kyphosis (n = 5), compression fractures (n = 4), progression of disc wedging (n = 2) and spinal stenosis (n = 2). Group UEV had more ASD (9 of 16 patients) compared to Group HV (2 of 21 patients) and Group HV-UEV (2 of 14 patients). It appeared that neutral vertebra could be a criterion for the selection of UIV in the coronal plane. Among the groups divided in the sagittal plane, proximal ASD was found in 47 % of 19 patients in Group L1-2, which was notably higher than 9 % in Group T9-10 and 20 % in Group T11-12.Proximal adjacent segment disease developed more commonly when the proximal fusion stopped at the UEV or below in adult degenerative lumbar scoliosis. UIV must be above UEV in the coronal plane. Fusion to T11 or T12 was acceptable when UIV was above UEV, since there was no significant difference in the rate of proximal adjacent segment between fusion to T10 and fusion to T11 or T12.

Pedicle screw instrumentation in AIS has advantages of rigid fixation, improved deformity correction and a shorter fusion, but needs an exacting technique. The author has been using the K-wire method with intraoperative single PA and lateral radiographs, because it is safe, accurate and fast. Pedicle screws are inserted in every segment on the correction side (thoracic concave) and every 2–3 on the supportive side (thoracic convex). After an over-bent rod is inserted on the corrective side, the rod is rotated 90° counterclockwise. This maneuver corrects the coronal and sagittal curves. Then the vertebra is derotated by direct vertebral rotation (DVR) correcting the rotational deformity. The direction of DVR should be opposite to that of the vertebral rotation. A rigid rod has to be used to prevent the rod from straightening out during the rod derotation and DVR. The ideal classification of AIS should address all curve patterns, predicts accurate fusion extent and have good inter/intraobserver reliability. The Suk classification matches the ideal classification is simple and memorable, and has only four structural curve patterns; single thoracic, double thoracic, double major and thoracolumbar/lumbar. Each curve has two types, A and B. When using pedicle screws in thoracic AIS, curves are usually fused from upper neutral to lower neutral vertebra. Identification of the end vertebra and the neutral vertebra is important in deciding the fusion levels and the direction of DVR. In lumbar AIS, fusion is performed from upper neutral vertebra to L3 or L4 depending on its curve types. Rod derotation and DVR using pedicle screw instrumentation give true three dimensional deformity correction in the treatment of AIS. Suk classification with these methods predicts exact fusion extent and is easy to understand and remember.

Retrospective study.To review the results and proximal adjacent problems of long fusion (more than 4 levels) according to the level of proximal fusion (L2~T9) in adult lumbar deformity using pedicle screw fixation.There are few written reports concerning proximal adjacent segmental failure according to the level of proximal fusion in adult lumbar deformity.The radiographs and clinical records of thirty-five patients (30 females, 5 males) of adult lumbar deformity with more than 2-year follow-up after surgery were analyzed. The average age was 62 years (range, 38~75). All patients were divided into three groups according to the level of proximal fusion: Group 1 (n=14) fusion up to L1 or L2; Group 2 (n=14) fusion up to T11 or T12; and Group 3 (n=7) fusion up to T9 or T10.The preoperative coronal curve of 28+/-14 degrees was corrected to 9+/-7 degrees immediately after surgery and 11+/-7 degrees at the final follow-up. The preoperative local kyphosis of 24+/-12 degrees was corrected to -1+/-10 degrees immediately after surgery and 1+/-11 degrees at the final follow-up. The lumbar lordosis was 14+/-18 degrees before surgery; 27+/-11 degrees after surgery; and 16+/-12 degrees at the final follow- up. The parameters of coronal and sagittal balance were improved in all patients after surgery, except one patient in group 2 who showed coronal imbalance due to over-correction. Sagittal imbalance at the most recent follow-up was detected in 10 patients with significant difference between the groups; 5 (36%) in Group 1, 5 (36%) in Group 2, and none in Group 3. Proximal adjacent segmental problems that are consisted with proximal disc degeneration with kyphosis, compression fractures above the fusion and screw failure proximal to the end of the fusion were observed in 15 patients with significant difference between the groups; 7 (50%) in Group 1, 7 (50%) in Group 2, and 1 (14%) in Group 3. There was 1 superficial infection and 2 transient neurologies.Fusion up to throacolumbar junction (L2~T11) in surgical treatment of adult lumbar deformity had more proximal adjacent problems with poorer results. Fusion higher than T10 is recommended for adult lumbar deformity.

With the advent of segmental pedicle screw fixation that enables more powerful corrective forces, it is postulated that an additional anterior procedure may be unnecessary even in severe deformities. The purpose of this paper is to evaluate the results of a posterior procedure alone using segmental pedicle screw fixation in severe scoliotic curves over 70 degrees . Thirty-five scoliosis patients treated by pedicle screw fixation and rod derotation were retrospectively analyzed after a minimum follow-up of 2 years (range 2-10.4). The mean age of patients was 15.3 years (range 9.8-34.2). Diagnoses were idiopathic scoliosis in 29, neuromuscular scoliosis in 3 and scoliosis associated with Marfan syndrome in 3. Scoliosis consisted of single thoracic curve in 18, double thoracic in 5 and double major in 12. Twenty-five patients showed a major thoracic curve greater than 70 degrees (range 70-100), and different ten patients showed a major lumbar curve greater than 70 degrees (range 70-105), pre-operatively. The deformity angle, lowest instrumented vertebral tilt (LIVT) and spinal balance were measured. Pre-operatively there were nine patients with coronal decompensation. The pre-operative thoracic curve of 80 +/- 9 degrees with the flexibility of 45 +/- 11% (45 +/- 11 degrees in side-bending film) was corrected to 27 +/- 10 degrees at the most recent follow-up, showing a correction of 66% (53 degrees) and loss of correction of 3.0% (3.7 degrees). The pre-operative lumbar curve of 79 +/- 12 degrees with the flexibility of 62 +/- 14% (30 +/- 11 degrees in side-bending film) was corrected to 33 +/- 14 degrees at the most recent follow-up [59% (46 degrees) curve correction, 3.5% (3.0 degrees) loss of curve correction]. The pre-operative LIVT of 30 +/- 8 degrees was corrected to 11 +/- 6 degrees, showing a correction of 62% (19 degrees). Residual coronal decompensation was observed in three patients postoperatively. Pre-operative thoracic kyphosis of 27 degrees (range 0-82) improved postoperatively to 31 degrees (range 14-53). In conclusion, posterior segmental pedicle screw fixation without anterior release in severe scoliosis had satisfactory deformity correction without significant loss of curve correction. In this series a posterior procedure alone obviated the need for the anterior release and avoided complications related anterior surgery.

Rationale: The management of congenital scoliosis concentrates on early diagnosis and proper surgical treatment before the development of severe deformities. Decision making regarding the appropriate fusion levels, proper surgical treatment, and reduction amount of kyphoscoliosis is very important but difficult in the treatment of congenital scoliosis, especially in young children. Patient concerns: We report an 11-year follow-up of revision surgery for fractional curve progression after combined anterior and posterior fusion without hemivertebra resection using pedicle screw fixation (PSF) in congenital kyphoscoliosis at age 4 years (a total 18-year follow-up). A T12 hemivertebra was documented in a 4-year-old girl and was treated by combined anterior and posterior fusion in two stages with PSF. The fusion mass was maintained but the distal compensatory curve progressed during the follow-up period. The patient underwent a posterior vertebral column resection (PVCR) with extended posterior fusion at the age of 11, 7 years after initial surgery. Outcomes: Eleven years after the revision surgery with PVCR, the patient showed satisfactory results and her spine was well balanced. Lessons: The cause of revision surgery for the curve progression may include inappropriate fusion level, incomplete hemivertebra resection, or failure of anterior and posterior fusion. Especially, inappropriate fusion level may result in deterioration of the compensatory curve even without progression of the fusion mass. Conclusion: Appropriate selection of fusion levels, complete resection of hemivertebra, and satisfactory reduction of scoliosis and kyphosis are important factors for deformity correction and prevention of progression of both main and compensatory curves (adding-on of structural curve or progression of compensatory curve) as well as reducing the influence of adjacent vertebral growth using as short a fusion as possible.

STUDY DESIGN A retrospective study. PURPOSE To determine the exact distal fusion level in the management of thoracolumbar/lumbar adolescent idiopathic scoliosis (TL/L AIS) using pedicle screw instrumentation (PSI). OVERVIEW OF LITERATURE The selection of distal fusion level remains controversial in TL/L AIS. METHODS Radiographic parameters of 66 TL/L AIS patients were analyzed. The patients were grouped according to the distal fusion level; L3 group (fusion to L3, n=58) and L4 group (fusion to L4, n=8). The L3 group was subdivided into L3A (L3 crosses the mid-sacral line with rotation of less than grade II, n=33) and L3B (L3 does not cross the mid-sacral line or rotation is grade II or more, n=25) based on both bending radiographs. All of the patients in the L4 group had the same location and rotation of L3 in bending films as that of patients in the L3B group. An unsatisfactory result was defined as a lowest instrumented vertebral tilt (LIVT) of more than 10° or coronal balance of more than 15 mm. RESULTS Among the 3 groups, there was a significantly lesser correction in the TL/L curve and LIVT in the L3B group. Unsatisfactory results were obtained in 3 patients (9.1%) of the L3A group, in 15 patients (68.2%) of the L3B group, and in 1 patient (12.5%) of the L4 group with a significant difference. CONCLUSIONS In TL/L AIS treatment with PSI, the curve can be fused to L3 with favorable radiographic outcomes when L3 crosses the mid-sacral line with rotation of less than grade II in bending films. Otherwise, fusion has to be extended to L4.

IntroducionThere is little information reported about the long term follow-up of surgical outcomes that pertain to the timing of surgery for congenital scoliosis in children under age 20 years. Thi...

Study Design Retrospective study. Purpose To evaluate the incidence and risk factors of complications following posterior vertebral resection (PVR) for spinal deformity. Methods A review of 233 patients treated with PVR at one institution over a nine-year period (1997 to 2005) was performed. The average age was 33.5 years. Complications were assessed in terms of surgical techniques (posterior vertebral column resection [PVCR] and decancellation osteotomy) and etiologies of deformity. Results Local kyphosis was corrected from 51.4° to 2.7°, thoracic scoliosis 63.9° to 24.5° (62.6% correction), and thoracolumbar or lumbar scoliosis 50.1° to 17.1° (67.6%). The overall incidence of complications was 40.3%. There was no significant difference between PVCR and decancellation osteotomy in the incidence of complications. There were more complications in the older patients (>35 years) than the younger (p < 0.05). Hig her than 3,000 ml of blood loss and 200 minutes of operation time increased the incidence of complications, with significant difference (p < 0.05). More than 5 levels of fusion significantly increased the total number of complications and postoperative neurologic deficit (p < 0.05). Most of the postoperative paraplegia cases had preoperative neurologic deficit. Preoperative kyphosis, especially in tuberculous sequela, had hig her incidences of complications and postoperative neurologic deficit (p < 0.05). More than 40° of kyphosis correction had the tendency to increase complications and postoperative neurologic deficit without statistical significance (p > 0.05). There was 1 mortality case by heart failure. Revision surgery was performed in 15 patients for metal failure or progressing curve. Conclusions The overall incidence of complications of PVR was 40.3%. Older age, abundant blood loss, preoperative kyphosis, and long fusion were risk factors for complications.

There is a debate regarding the distal fusion level for degenerative lumbar scoliosis. Whether a healthy L5-S1 motion segment should be included or not in the fusion remains controversial. The purpose of this study was to determine the optimal indication for the fusion to the sacrum, and to compare the results of distal fusion to L5 versus the sacrum in the long instrumented fusion for degenerative lumbar scoliosis. A total of 45 patients who had undergone long instrumentation and fusion for degenerative lumbar scoliosis were evaluated with a minimum 2 year follow-up. Twenty-four patients (mean age 63.6) underwent fusion to L5 and 21 patients (mean age 65.6) underwent fusion to the sacrum. Supplemental interbody fusion was performed in 12 patients in the L5 group and eleven patients in the sacrum group. The number of levels fused was 6.08 segments (range 4-8) in the L5 group and 6.09 (range 4-9) in the sacrum group. Intraoperative blood loss (2,754 ml versus 2,938 ml) and operative time (220 min versus 229 min) were similar in both groups. The Cobb angle changed from 24.7 degrees before surgery to 6.8 degrees after surgery in the L5 group, and from 22.8 degrees to 7.7 degrees in the sacrum group without statistical difference. Correction of lumbar lordosis was statistically better in the sacrum group (P = 0.03). Less correction of lumbar lordosis in the L5 group seemed to be associated with subsequent advanced L5-S1 disc degeneration. The change of coronal and sagittal imbalance was not different in both groups. Subsequent advanced L5-S1 disc degeneration occurred in 58% of the patients in the L5 group. Symptomatic adjacent segment disease at L5-S1 developed in five patients. Interestingly, the development of adjacent segment disease was not related to the preoperative grade of disc degeneration, which proved minimal degeneration in the five patients. In the L5 group, there were nine patients of complications at L5-S1 segment, including adjacent segment disease at L5-S1 and loosening of L5 screws. Seven of the nine patients showed preoperative sagittal imbalance and/or lumbar hypolordosis, which might be risk factors of complications at L5-S1. For the patients with sagittal imbalance and lumbar hypolordosis, L5-S1 should be included in the fusion even if L5-S1 disc was minimal degeneration.

The extent of fusion for degenerative lumbar scoliosis has not yet been determined. The purpose of this study was to compare the results of short fusion versus long fusion for degenerative lumbar scoliosis. Fifty patients (mean age 65.5 +/- 5.1 years) undergoing decompression and fusion with pedicle screw instrumentation were evaluated. Short fusion was defined as fusion within the deformity, not exceeding the end vertebra. Long fusion was defined as fusion extended above the upper end vertebra. The lower end vertebra was included in the fusion in all the patients. The short fusion group included 28 patients and the long fusion group included 22 patients. Patients' age and number of medical co-morbidities were similar in both the groups. The number of levels fused was 3.1 +/- 0.9 segments in the short fusion group and 6.5 +/- 1.5 in the long fusion group. Before surgery, the average Cobb angle was 16.3 degrees (range 11-28 degrees ) in the short fusion group and 21.7 degrees (range 12-33 degrees ) in the long fusion group. The correction of the Cobb angle averaged 39% in the short fusion group and 72% in the long fusion group with a statistical difference (P = 0.001). Coronal imbalance improved significantly in the long fusion group more than in the short fusion group (P = 0.03). The correction of lateral listhesis was better in the long fusion group (P = 0.02). However, there was no difference in the correction of lumbar lordosis and sagittal imbalance between the two groups. Ten of the 50 patients had additional posterolateral lumbar interbody fusion at L4-5 or L5-S1. The interbody fusion had a positive influence in improving lumbar lordosis, but was ineffective at restoring sagittal imbalance. Early perioperative complications were likely to develop in the long fusion group. Late complications included adjacent segment disease, loosening of screws, and pseudarthrosis. Adjacent segment disease developed in ten patients in the short fusion group, and in five patients in the long fusion group. In the short fusion group, adjacent segment disease occurred proximally in all of the ten patients. Loosening of distal screws developed in three patients, and pseudarthrosis at L5-S1 in one patient in the long fusion group. Reoperation was performed in four patients in the long fusion group and three patients in the short fusion group. In conclusion, short fusion is sufficient for patients with small Cobb angle and good spinal balance. For patients with severe Cobb angle and rotatory subluxation, long fusion should be carried out to minimize adjacent segment disease. For patients who have severe sagittal imbalance, spinal osteotomy is an alternative technique to be considered. As long fusion is likely to increase early perioperative complications, great care should be taken for high-risk patients to avoid complications.

Introduction There is no report on the effect of DVR on the shoulder balance using segmental pedicle screw instrumentation in the treatment of double thoracic adolescent idiopathic scoliosis (AIS) with minimum 5-year follow-up. This study is to evaluate the shoulder balance resulting from the correction of double thoracic AIS comparing rod derotation (RD) with direct vertebral rotation (DVR) and RD only following pedicle screw instrumentations. Materials and Methods Double thoracic AIS patients ( n = 57) were treated by fusing both thoracic curves with RD and DVR ( n = 35), or RD ( n = 22) methods and retrospectively studied with a minimum 5 years follow-up. Results In the RD with DVR group, the preoperative PT curve of 40.2 degrees improved to 17.9 degrees postoperatively and 19.9 degrees at last follow-up. In the RD group, the preoperative PT curve of 37.5 degrees improved to 22.4 degrees postoperatively and 23.2 degrees at last follow-up. In the RD with DVR group, the preoperative DT curve of 56.6 degrees improved to 16.1 degrees postoperatively and 16.7 degrees at last follow-up. In the RD group, the preoperative DT curve of 50.6 degrees improved to 17.8 degrees postoperatively and 18.2 degrees at last follow-up. In the RD with DVR group, the average preoperative SHD of 16.3 mm was improved to 7.2 mm postoperatively and was 7.0 mm at last follow-up. In the RD group, the average preoperative SHD of 15.1 mm was changed to 7.5 mm postoperatively and was 7.3 mm at last follow-up. Conclusion Shoulder balance was not significantly improved even with additional correction method of DVR using segmental pedicle screw instrumentation in double thoracic AIS. The PT curve was rigid and corrected less in both groups. Therefore, less correction of the DT curve effectively achieves better shoulder balance.

Study Design: This is a retrospective study. Objectives: We wanted to assess the stability of distal instrumentation using the bilateral S1 and sacral alar screws for the treatment of degenerative lumbar deformity. Summary of the Literature Review: Various instrumentation methods have been introduced for increasing the strength of lumbosacral fusion. However, there are not many clinical studies that have evaluated the effectiveness of a sub-S1 alar screw for treating degenerative lumbar deformity surgery. Materials and Methods: A total of 39 patients with degenerative lumbar deformity were treated by long fusion and we retrospectively analyzed these patients after a minimum follow-up of 1 year. All the patients underwent an operation with distal instrumentation using either bilateral S1 screws alone (the S1 group) or additional bilateral sub-S1 sacral alar screws (the SA group). There were 19 patients in the S1 group and 20 patients in the SA group. The stability of the distal instrumentation was assessed by breakage or backout of a rod and/or screws based on simple radiography. Results: Instability of the distal instrumentation was detected in 6 cases (32%) in the S1 group and in 1 case (5%) in the SA group. The SA group had a more stability of the distal instrumentation than that of the S1 group with a significant difference (P 0.05). Conclusions: Bilateral sacral alar screws coupled with bilateral S1 screws can provide good distal fixation for stability of the distal instrumentation when performing long fusion for treating degenerative lumbar deformity.

Purpose: To analyze survival rates of patients after mono-segmental lumbar or lumbosacral fusion and to evaluate factors affecting the revision operation due to adjacent segmental degeneration. Materials and Methods: This study enrolled 1,206 patients who had mono-segmental lumbar or lumbosacral fusion between March 1997 and December 2006 at the Seoul Spine Institute. The survival rates for the revision operation due to adjacent segmental degeneration were analyzed retrospectively. The age at index operation, sex, etiologic diagnosis, fusion method, fusion level, substance of bone graft, operator, body mass index (BMI), and smoking were considered as risk factors for the revision operation. Results: There were 27 patients with a revision operation for adjacent segmental degeneration (2.24%). The average follow-up period was 39.0 months (6 months to 12 years 6 months) and the average age at operation was 47.0 years (13 to 85 years). The sur vival rate at 5 years was 97.3%, and at 10 years it was 89.4%. Patients less than 50 years old had a significantly lower revision operation rate than those aged 50 or more (p=0.002). When fusion between the 4th lumbar and the 5th lumbar spinal vertebrae was done, the revision operation rate was significantly higher than for other levels (p=0.003). Obese patients with had a significantly higher revision rate than did patients with BMI0.05). In multivariate analysis, age alone was a significant risk factor (p=0.048, Hazard ratio=2.50). Conclusion: The most important factor for survival without revision surgery for adjacent segmental degeneration following instrumented mono-segment lumbar or lumbosacral fusion is the age at index operation. Patients 50 year-old or older should be informed of the possibility of adjacent segmental disease after instrumented mono-segment lumbar or lumbosacral fusion.

Objectives : To report the surgical technique and effectiveness in treating rigid adult scoliosis with one stage vertebral column resection and pedicle screw fixation through a single posterior approach(PVCR). Materials and Methods : Twenty-one patients with low flexibility(less than 20~30%) subjected to PVCR were evaluated after a mean follow-up of 18.5 months(12~29 months). There were 10 males and 11 females. The mean age at the time of the operation was 32.1 years(19~61 years). Etiological diagnoses were idiopathic in 7, congenital in 12, neuromuscular in 2. Preoperatively, all the patients showed moderate to severe derangement of pulmonary function with reduced vital capacity(30%~57%). Results : An average of 1.3 vertebrae(1~3 vertebrae) were removed. The resection of body was in thoracic in 12 and lumbar in 15. Posterior fusion was carried out in 6.8(3~12) levels. Following the surgery, preoperative thoracic scoliosis of 86 (55~130 ) and lumbar scoliosis of 64 ( 3 5~1 1 0 ) were corrected to 38 ( 1 5~6 5 ) and 25 ( 1 4~6 1 ), showing a correction of 56.2%(39~78%) and 6 1 . 1 % ( 4 4~82%) respectively. Preoperative kyphosis of 59 ( 1 6~1 0 4 ) was corrected to 24 ( 2~5 8 ), showing a correction of 60.2%(41~74%). Preoperative coronal imbalance and shoulder height difference was corrected to 0.6 cm and 1.0 cm respectively. The average operation time and transfusion were 253 minutes and 2835 ml. The complications comprised two transient neurological deficits, one aggravated neurological deficits, one monoparesis, one infection, and one pneumothorax. Conclusion : One stage posterior vertebral column resection is a promising new technique for rigid scoliosis, significantly reducing the operative time and morbidity of combined anterior-posterior resection.

Materials a and M Methods: The sagittal curves were analyzed in normal adolescents (N-adol group, n=23) and patients with thoracic AIS (AIS group, n=26) who had thoracic curves ≥ 45� . Lateral standing radiographs of the cervical spine with a elbow straight and the whole spine with the hands on the clavicles were taken. The sagittal curves and balance were measured in the following segments; C2-C7, T2-T5, T5-12, T2-12, T12-S1. Cervical lordosis (C2-C7) was measured in both cervical spine radiographs and whole spine radiographs. Results: In the N-adol group, the cervical lordosis was 9.2±14.6�in the cervical spine radiographs and -0.6±12.9�(‘-’ means kyphosis) in whole spine radiographs. In the AIS group, cervical lordosis was -5.0±12.9�in the cervical radiographs and -8.1± 12.7�in the whole radiographs. The AIS group had significantly less cervical lordosis than the N-adol group. Thoracic kyphosis of T5-12 and T2-12 was 24.1±10.6�and 38.9±13.1�in the N-adol group, respectively, and 17.8±9.4�and 30.1±11.8�in the AIS group, respectively. There was a significant difference between the two groups (Ps 0.05). In the AIS group, the cervical lordosis measured in the cervical spine radiograph showed a positive correlation with thoracic kyphosis of T2-5 (r=0.50, P=0.009) and T2-12 (r=0.57, P=0.003). Conclusions: AIS patients had significantly less cervical lordosis and thoracic kyphosis than normal adolescents. Decreased cervical lordosis in AIS had a significant correlation with their relative thoracic hypokyphosis.

Purpose: Adjacent segment disease (ASD) is major complication following spinal instrumentation and fusion. The purpose of the current study was to determine the prevalence and risk factors of proximal ASD following posterior instrumentation and fusion for degenerative lumbar scoliosis. Materials and Methods: Seventy-two patients (mean age 64.8 years) who had undergone decompression and fusion with pedicle screw instrumentation were evaluated. The average follow-up was 4.7 years. Twenty-five patients had additional interbody fusion at the lower lumbar spine. The average number of levels fused was 5.1 segments (range 1-9). The upper instrumented vertebrae ranged from T9 to L4. The lower instrumented vertebrae were L5 and S1. Results: Proximal ASD developed in 17 (24%) of 72 patients, including compression fractures (n=6), junctional kyphosis (n=5), spinal stenosis (n=4), and symptomatic disc collapse (n=2). The preoperative scoliotic angle, lumbar lordosis, thoracic kyphosis, and coronal and sagittal C7 plumb were not associated with the development of proximal ASD. There was a close correlation between the level of the upper instrumented vertebrae and the development of ASD (p=0.001). When fusion did not extend beyond the lumbar vertebra, ASD occurred in 15 (38.5%) of 39 patients. In contrast, when fusion extended up to the thoracic vertebrae, ASD occurred in 2 (6.1%) of 33 patients. The improvement in the Oswestry score was superior to the group without ASD (p=0.001). Conclusion: The prevalence of symptomatic ASD at the proximal segment was 24% after posterior instrumentation and fusion for degenerative lumbar scoliosis. The cephalad extent of fusion was the most significant risk factor for the development of proximal ASD.

Study Design: Retrospective study Objectives: To evaluate the surgical outcome of congenital scoliosis with a hemivertebra treated by posterior hemivertebra excision and pedicle screw instrumentation. Summary of Literature Review: Posterior hemivertebra excision can be accomplished through a single posterior approach, and excellent correction and outcome may be achieved. Materials and Methods: Forty patients with one fully segmented hemivertebra treated by posterior hemivertebra excision with pedicle screw instrumentation were retrospectively analyzed after a minimum follow-up of 2 years (range 2~7.7 years). The mean age at surgery was 15.9 years (range 2.6~37.9 years). Preoperative and postoperative standing radiographs were used to assess radiographic parameters. Results: The average number of vertebrae in the major curve was 4.2 (range 3~8), and the average flexibility was 29% (range 8~59%). The average length of fusion was 3.5 segments (range 1~6). The number of fused vertebrae had a positive correlation with age at the index surgery (r=0.345, p�0.05). Mean preoperative scoliosis of 48±12。was corrected to a mean of 17±10。 (65% correction), and mean preoperative kyphosis of 46±18。was corrected to a mean of 12±12。at the most recent follow-up. The compensatory curve had a mean of 25±10。preoperatively and spontaneously corrected to a mean of 8±8。(70% correction) at the most recent follow-up. The mean operating time was 233±81 min, with an average blood loss of 2904 ml. There was neither crankshaft phenomenon nor iatrogenic spinal stenosis in 6 patients under the age of 5 years after an average follow-up of 6 years. Conclusions: Posterior hemivertebra excision using pedicle screw instrumentation in congenital scoliosis due to a hemivertebra is a safe and effective procedure. Posterior hemivertebra excision at an early age may reduce the fusion length while avoiding the induction of iatrogenic spinal stenosis during follow-up.

Purpose: To compare the results of two different surgical methods (translation vs rod derotation) in a correction of double thoracic adolescent idiopathic scoliosis (AIS) using pedicle screw instrumentation. Materials and Methods: Forty-seven patients with double thoracic AIS treated by pedicle screw instrumentation were reviewed retrospectively after a minimum follow-up of 2 years. The patients were divided into two groups; TR group (translation method, n=14) and RD group (rod derotation, n=33). There were no significant differences in the preoperative curve characteristics between the two groups. Results: In the TR group, the preoperative upper thoracic curve of 37±4˚ improved to 24±4˚ (35% correction), and the lower thoracic curve of 52±9˚ improved to 18±5˚ (65% correction). In the RD group, the preoperative upper thoracic curve of 40±7˚ improved to 19±7˚ (51% correction), and the lower thoracic curve of 56±12˚ was improved to 16±6˚ (72% correction). The correction of the upper and lower thoracic curves was significantly better in the RD group (p

Purpose: To compare the results of short fusion versus long fusion for degenerative lumbar scoliosis. Materials and Methods: Forty-seven patients undergoing short fusion (n=28) and long fusion and instrumentation (n=19) were evaluated. Short fusion was defined as fusion within the deformity, not exceeding the upper end vertebra. Long fusion was defined as fusion extended above the upper end vertebra. The number of levels fused in the short and long fusion groups was 3.14 and 6.89 segments, respectively. Results: Before surgery, the Cobb angle was 16.3o in the short fusion group and 22o in the long fusion group, which changed to 10.1o and 8.47o, respectively, at the last visit. The correction of coronal imbalance was better in the long fusion group. In contrast, the correction of sagittal imbalance was similar in both groups. The mean estimated blood loss in the short and long fusion groups was 1,671 ml and 2,742 ml, respectively. Early perioperative complications developed frequently in the long fusion group. Adjacent segment disease occurred more frequently in the short fusion group. Conclusion: Long fusion and instrumentation for degenerative lumbar scoliosis was better at correcting the coronal deformity and imbalance than short fusion but was ineffective in correcting the sagittal imbalance.

Purpose : To assess the results of double thoracic fusion using pedicle screw instrumentation fused proximally to T1 or T2 in patients with double thoracic adolescent idiopathic scoliosis (AIS). Materials and Methods : Forty patients with double thoracic AIS were analyzed retrospectively after a minimum follow-up of 2 years. The patients were divided into two groups according to the proximal fusion level: the T1 group (n=26) was fused to T1 and the T2 group (n=14) was fused to T2. Results : There were no significant differences in the preoperative curve characteristics between the two groups. In the T1 group, the preoperative upper curve magnitude of 38±7˚ and apical vertebral translation (AVT) of 8±6 mm were corrected to 17±7˚ (54% correction) and 4±3 mm (3 mm correction) at the final follow-up, respectively. In the T2 group, the preoperative upper curve magnitude of 37±5˚ and the AVT of 7±4 mm were corrected to 22±6˚ (42% correction) and 6±3 mm (1 mm correction) at the final follow-up, respectively. There was no difference in the correction of lower thoracic curve, sagittal alignment and balance between the two groups. There was a significantly better correction in the upper thoracic curve and T1 tilting in the T1 group than the the T2 group. Conclusion : In double thoracic AIS, fusions to T1 and T2 produce satisfactory results. However, fusion to T1 is recommended for a better correction of the upper curve and T1 tilting.

‐ Abstract ‐ Study Design: This is a retrospective study. Objectives: We wanted to evaluate the outcomes of selective thoracic fusion with segmental pedicle screw fixation for treating thoracic idiopathic scoliosis with a minimum 5-year follow-up. Summary of the Literature Review: Segmental pedicle screw fixation has been proven to achieve true segmental control and greater correction of scoliosis in both the coronal and sagittal planes. However, there is no long-term study of selective thoracic fusion with segmental pedicle screw fixation for treating thoracic idiopathic scoliosis. Materials and Methods: We analyzed 203 thoracic idiopathic scoliosis patients (236 thoracic curves) who underwent selective thoracic fusion with segmental pedicle screw fixation. The mean patient age at the time of operation was 13.8 years (range: 8.9~18 years). Results: The preoperative thoracic curve of 51±12°was corrected to 16±7°(69% correction with 3% loss of correction) at the most recent follow-up. The non-instrumented lumbar curve of 30±10°was corrected to 10±8°(66% correction with 5% loss of correction) at the most recent follow-up. The preoperative thoracic kyphosis of 18±11°and the lumbar lordosis of 43±10° were improved to 23±8°and 46±9° , respectively, at the most recent follow-up. There was no junctional kyphosis at the most recent follow-up. Coronal decompensation at the most recent follow-up occurred in 10 patients. Postoperative adding-on occurred in 17 patients who were fused two levels short of the neutral vertebra. Of the 2867 thoracic pedicle screws inserted at the thoracic level, 43 screws were found to be malpositioned (1.5%), but they did not cause neurologic complications or adversely affect the long-term results. Conclusions: Selective thoracic fusion with segmental pedicle screw fixation for treating thoracic idiopathic scoliosis had satisfactory radiographic and clinical outcomes after surgery, and the outcomes were well-maintained for a minimum of 5 years follow-up. It is a safe and effective method for preserving segments of lumbar motion as well as for the restoration and maintenance of both the coronal and sagittal alignments.

Study Design: A retrospective cross-sectional study Objectives: To analyze the prevalence and characteristics of lumbar scoliosis using plain abdominal X-rays, according to age. Literature Review Summary: The single lumbar curves of adolescents have shown 10∼20% idiopathic scoliosis, but the reported prevalence of adult lumbar scoliosis ranges from 2.5 to 7.5%. In Korea, there is no useful basic data concerning lumbar scoliosis. Materials and Methods: A total of 2877 plain abdominal radiographies (supine and erect), taken at our hospital, between August 2001 and June 2002, were retrospectively investigated. The ages of the patients ranged from 11 to 80 years, and the patients were grouped according to age. The prevalence, Cobb angle, ratio of males and females, ratio of right and left curves, location of end and apex vertebra, the number of involved vertebra in primary curve, amount of rotation and osteophytes were all examined. Results: The overall prevalence of lumbar scoliosis was 4.3% (N=124), but rapidly increased after the sixth decade. The average Cobb angle was 16.2。. A positive correlation was found between the Cobb angle and age (r=0.275, P

Study Design: A retrospective study. Objectives: To evaluate the results of posterior segmental pedicle screw fixation in skeletally immature patients with scoliosis. Summary of Literature Review: Scoliosis correction, in the immature spine, frequently necessitates additional anterior surgery to prevent the crankshaft phenomenon. With the advent of posterior segmental pedicle screw fixation, it is unclear whether an additional anterior procedure will be required. Material and Methods: Seventeen scoliosis patients (10 idiopathic, 4 congenital and 3 others; 3 males and 14 females) were treated with segmental pedicle screw fixation only. Their results were reviewed for a deformity progression of more than 10 ○ , a rib vertebra angle difference (RVAD) progression of more than 10 ○ , and evidence of adding-on. All the patients had a 0 Risser index at the time of the operation. The mean age and follow-up times were 10.4, ranging from 7.2 to 11.8 years old, and 4.0, ranging from 3.0 to 5.4 years, respectively. Results: The mean preoperative thoracic curve of 55 ○ was corrected to 22 ○ (58% correction) at last follow-up and the nonstructural lumbar curve of 31 ○ was corrected to 10 ○ (67% correction) at last follow-up. Preoperative thoracic kyphosis of 28 ○

Study Design: A prospective study. Objectives: To introduce a new technique, direct vertebral rotation (DVR), and to compare the surgical results with those of a simple rod derotation (SRD). Summary of Background Data: Pedicle screw fixation, with a simple rod derotation maneuver, enables powerful coronal and sagittal plane corrections in scoliosis surgery. However, the ability for rotational correction is still unclear. Methods: Thirty-eight AIS patients, treated with segmental pedicle screw fixation, were analyzed. The first group (n=17) was treated by DVR, and the second (n=21) by SRD. Having similar preoperative curve patterns, both groups were evaluated for the deformity correction and spinal balance. Results: In the DVR group, the average preoperative AVR of 16.7°was corrected to 9.6°, showing a 42.5% correction, while in the SRD group, the correction was negligible, from 16.1°to 15.7°(2.4%). In the DVR group, the preoperative thoracic curve of 55°was corrected to 12°(79.6%), and the lumbar curve from 39°to 7°(80.5%). In the SRD group, the preoperative thoracic curve of 53°was corrected to 17°(68.9%), and the lumbar curve from 39°to 16°(62.2%). The average LIVT correction was 80.6 and 66.3% in the DVR and SRD group, respectively. There were statistically significant differences in the coronal curve, LIVT and rotational correction (p

Study Design : A retrospective study. Objectives : To analyze natural history and clinical features of scoliosis developed after surgery for congenital heart disease and to investigate the influence of cardiac surgery on the onset and progression of scoliosis.. Materials and methods : Three hundred and five patients who had been operated for congenital heart disease from Jan.1988 to Dec.1990 and followed up for more than 5 years were analyzed. The curve which was more than 10 on radiography was defined as significant scoliosis and the patients with congenital spinal anomalies were excluded. We compared age at surgery, cardiac disease and effect of cyanosis between scoliosis and non-scoliosis group. Furthermore, in scoliosis group, prevalence, onset of significant scoliosis, and manifestation of curve according to side of thoracotomy were assessed. Results : Fifty-six patients(18.4%) had scoliosis of more than 10 . As for location, high thoracic in 19, thoracic in 23, double thoracic in 8, thoraco-lumbar in 5 and double major in 1. Of the 42 patients with thoracic or high thoracic curves, 17(40%) showed convexity to the left. The magnitudes of curves were less than 40 degrees except 1. There was no significant difference in prevalence(p=0.513) and Cobb angle(p=0.634) between cyanosis and acyanosis group. Scoliosis developed between 3 and 6 years after cardiac operation in 26 patients(46%). In high thoracic curve, 6 of 7 patients with left thoracotomy demonstrated convexity to the left and 5 of 6 patients with right thoracotomy demonstrated convexity to the right(p=0.026). Conclusions : The prevalence of scoliosis after surgery for congenital heart disease was 18.4%. High thoracic and left thoracic curves were more frequent compared to idiopathic curves and a half of them developed 3 to 6 years after cardiac surgery. Most patients did not have severe curve to need surgical intervention and there was no correlation between severity of scoliosis and age at cardiac operation and cyanosis. In high thoracic curve, the tendency for the curve to be convex to the side of cardiac approach was demonstrated.

Purpose : To measure bending stiffness of rod in pedicle screw systems and identify the optimal rod for surgical correction of spinal deformities. Materials and Methods : Bending stiffness of six different rods 7 mm stainless steel, 6 mm titanium alloy, 6.35 mm titanium, 5.5 mm titanium, 6 mm Shape Memory Alloy after martensite temperature, 7 mm Shape Memory Alloy after martensite temperature-were measured by MTS 858 Bionix test system according to the ASTM standards. The specimen number was 8 for each rod. Young’s modulus of elasticity was calculated from load-displacement data. Results : Seven-mm stainless steel rod was stiffer than any other rods with bending stiffness of 143.7±3.8 N/mm, and also showed largest Young’s modulus of elasticity of 135.1±3.0 GPa. Six-mm Shape Memory Alloy rod after martensite temperature was most flexible with bending stiffness of 58.1±2.8 N/mm, and showed smallest Young ’s modulus of elasticity of 68.0± 2.1 GPa. Seven-mm Shape Memory Alloy rod after martensite temperature was similar to the 6.35 mm titanium and 6 mm titanium alloy rod in bending stiffness and Young’s modulus of elasticity. Conclusion : Seven-mm stainless steel rod was the stiffest rod tested, which is necessary to improve correction rate and maintain achieved correction. However, the rod selection should be individulized since stiffer rod might increase the chance of acute failure. Seven-mm Shape Memory Alloy could be more useful in deformity correction than 6 mm Shape Memory Alloy since it was not only similar to other rods in stiffness but also had shape memory function which would be necessary to establish the desired position of the spine.