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Background context Anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PPF) provides successful surgical outcomes to isthmic spondylolisthesis patients with indirect decompression through foraminal volume expansion. However, indirect decompression through ALIF followed by PPF may not obtain a successful surgical outcome in patients with isthmic spondylolisthesis accompanied by foraminal stenosis caused by a posterior osteophyte or foraminal sequestrated disc herniation. Thus far, there has been no report of foraminal decompression through anterior direct access in the lumbar spine. Purpose This study aims to describe the new surgical technique of microscopic anterior foraminal decompression and to analyze the clinical outcomes and radiologic results of the microscopic anterior decompression during ALIF followed by PPF. Study design/Setting We conducted a multisurgeon, retrospective, clinical series from a single institution. Patient sample This study was carried out from March 2007 to July 2010 and included 40 consecutive patients with isthmic spondylolisthesis accompanied by foraminal stenosis caused by posterior osteophyte or foraminal sequestrated disc herniation undergoing microscopic anterior foraminal decompression during ALIF followed by PPF. Outcome measures The visual analog scales (VAS) of back and leg pain and the Oswestry disability index were measured preoperatively and at the last follow-up. Methods Postoperative computed tomography and magnetic resonance imaging measured whether decompression of neural structure had been made and morphometric change of the foramen and the amount of resected bone. Moreover, segmental lordosis, whole lumbar lordosis, disc height, and degree of listhesis were measured through X-ray examination before the operation and at the last follow-up; we also verified whether fusion had been achieved. Results Successful decompression was confirmed in both patients with foraminal stenosis caused by posterior osteophyte and those with foraminal sequestrated disc herniation. Clinically, compared with before the surgery, the VAS (leg and back) and the Oswestry disability index significantly decreased at the last follow-up (p=.000). With regard to radiology, at the last follow-up all patients had bone fusion on X-ray examination, and an increase in disc height, a reduction in the degree of listhesis, an increase in segmental lordosis, and an increase in whole lumbar lordosis were significant in both groups (p=.000) compared with before the surgery. Foraminal volume, foraminal width, and foraminal height also significantly increased postoperatively compared with before the operation (p=.000). The height, width, and dimension of resected body were 4.61±1.05 mm, 7.92±1.42 mm, 17.15±4.96 mm 2 , respectively, in patients with foraminal stenosis caused by a posterior osteophyte, and 3.88±0.92 mm, 6.8±1.29 mm, and 13.12±2.25 mm 2 , respectively, in patients with foraminal sequestrated disc. Conclusions The microscopic anterior foraminal approach provides successful foraminal decompression. Combined with ALIF and PPF, this approach shows a good surgical outcome in patients with isthmic spondylolisthesis accompanied by foraminal stenosis caused by a posterior osteophyte or those with foraminal sequestrated disc herniation.

STUDY DESIGN Retrospective study. OBJECTIVES To compare the surgical results between combined anterior-posterior procedures and posterior closing wedge osteotomy procedures in patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fractures. SUMMARY OF BACKGROUND DATA Combined anterior-posterior procedures are usually recommended in cases of kyphotic deformities with neurologic deficit secondary to osteoporosis. However, combined anterior-posterior surgery is associated with significant morbidity in elderly patients. MATERIALS AND METHODS Twenty-six patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fracture were indicated for operative intervention using either a combined anterior-posterior surgery (n = 11) or a posterior closing wedge osteotomy procedure (n = 15). The results of the two procedures were analyzed. The average patient age at the operation was 62.6 years (range: 50-82) with a 12:14 male-to-female ratio. Mean follow-up was 3.5 years (range: 2.1-5.4). Preoperative interval from injury to operation was 15.4 months (range: 1-36). There were 20 thoracolumbar (T12-L1) fractures and six lumbar fractures indicated for operative intervention. RESULTS In the combined anterior-posterior group, the mean operative time was 351 minutes with a mean blood loss of 2,892 mL. In the posterior closing wedge osteotomy group, the mean operative time was 215 minutes with blood loss of 1,930 mL. Eighteen patients showed a postoperative improvement in Frankel grading, 64% (7/11) in the combined anterior-posterior group, and 73% (11/15) in posterior closing wedge osteotomy group. There were no neurologic or vascular complications in either group. In the combined anterior-posterior group, there were five complications: two postoperative pneumonias, one superficial infection, and two distal screw loosening. There were only two complications in the posterior closing wedge osteotomy group: two distal screw loosening. One of the four cases of distal screw loosening required surgical revision. The other three cases were treated by bracing for more than 6 months. CONCLUSIONS Although technically demanding, the posterior closing wedge osteotomy procedure demonstrated a better surgical result with significant less mean operative time and mean blood loss (P < 0.05). It may be a better alternative than a combined anterior-posterior procedure in patients with posttraumatic kyphosis and neurologic compromise secondary to osteoporotic fracture.

Study design Retrospective study. Objectives To report a technique of vertebral column resection through a single posterior approach and its preliminary results in the treatment of moderate to severe spinal deformities with limited flexibility. Summary of background data Vertebral column resection is a formidable operation reserved for moderate to severe deformities with limited flexibility. The authors devised a technique of vertebral column resection through a single posterior approach that offers significant advantages over the anterior-posterior vertebral column resection. Methods Seventy spinal deformity patients treated by posterior vertebral column resection were reviewed. Minimum follow-up was 2 years (range 2-3.3 years). There were 34 males and 36 females with a mean age of 27.4 years at the time of the operation. Etiologic diagnoses were adult scoliosis in 7, congenital kyphoscoliosis in 38, and postinfectious kyphosis in 25. The surgery consisted of temporary stabilization of the vertebral column with segmental pedicle screw fixation, resection of the vertebral column at the apex of the deformity via the posterior route, followed by gradual deformity correction and global fusion. Results The total number of resected vertebrae was 143: 76 in thoracic and 67 in lumbar. Mean operation time was 4 hours, 31 minutes with average blood loss of 2333 mL. The deformity correction was 61.9% in the coronal plane and 45.2 degrees in the sagittal plane. Complications were encountered in 24 patients: 2 complete cord injuries in severe adult scoliosis and thoracic kyphosis patient who had significant preoperative cord compromise, 6 hematomas, 4 root injuries (all incomplete), 5 fixation failures, 2 infections, and 5 hemopneumothoraxes. Conclusions Posterior vertebral column resection is an effective alternative for moderate to severe deformities with limited flexibility. However, it is a technically demanding and exhausting procedure with possible risks for major complications.

Study design A retrospective study. Objective To determine the safety of pedicle screw fixation in thoracic deformity correction. Summary of background data Pedicle screw fixation enables enhanced correction of spinal deformities. However, the technique is still not widely applied for thoracic deformities for fear of neurologic complications. Materials and methods A total of 462 patients subjected to thoracic pedicle screw fixation for spinal deformities were analyzed after a minimum follow-up of 2 years. Etiologic diagnoses were idiopathic scoliosis in 330, congenital kyphoscoliosis in 68, kyphosis in 50, and others in 14. They were reviewed using the medical records and preoperative, intraoperative, and postoperative roentgenograms. Computed tomography was performed when screw position was questionable. Results A total of 4604 thoracic pedicle screws were inserted (10.1 screws/patient). There were 67 screw malpositions (1.5%) in 48 patients (10.4%). The malpositions were inferior in 33, lateral in 18, superior in 12, and medial in 4. Screw-related neurologic complications occurred in four patients (0.8%); these comprised a transient paraparesis and three dural tears. Other complications comprised 11 intraoperative pedicle fractures, 35 screw loosenings, 9 postoperative infections, and 1 pneumothorax. There were no significant screw-related neurologic or visceral complications that adversely affected the long-term result. The deformity correction was 69.9% for idiopathic scoliosis and 60.7% for congenital scoliosis. The sagittal plane deformity correction was 47 degrees for kyphosis. Conclusions Thoracic pedicle screw fixation is a reliable method of treating spinal deformities, with an excellent deformity correction and a high margin of safety.

STUDY DESIGN Retrospective study. OBJECTIVES To report the results and the technique of posterior vertebral column resection (PVCR) in fixed lumbosacral deformity. SUMMARY OF BACKGROUND DATA Fixed lumbosacral deformity has gross imbalance as well as progressive compensatory thoracolumbar deformity because of the absence of a mobile spine caudally. There is no consensus of the surgical treatment of fixed lumbosacral deformity. Fixed lumbosacral deformity can be managed by PVCR, which not only corrects the deformity but also restores the trunk balance by translation of spinal column. METHODS Twenty-five consecutive fixed lumbosacral deformity patients subjected to PVCR were reviewed after a minimum follow-up of 2 years. The apical vertebra and the ultimately resected vertebra were below L4 in most cases. Etiologic diagnoses were congenital scoliosis in 6, congenital kyphoscoliosis in 3, post-traumatic kyphosis in 2, and postinfectious kyphosis in 14. The average age at the operation was 38 years (range, 2.5-61 years) with a male:female ratio of 7:18. The indication for PVCR was fixed lumbosacral deformities that could not be brought to a reasonable balance on traction or forced side bending. Before surgery, 12 patients (48%) presented with neurologic compromise and 20 patients (80%) presented with intractable back pain. The surgical technique consisted of segmental pedicle screw fixation, decompression of neural structures, and resection of the vertebral column at the apex of the deformity via the posterior route, followed by deformity correction and global fusion. During the resection, all the nerve roots were preserved. RESULTS Two and one tenth (2.1) vertebrae removed on average (range, 1-5 vertebrae), and 52 in all. The average fusion extent was 4.5 vertebrae (range, 2-8 vertebrae). The anterior column reconstruction was carried out with autogenous bone graft in all patients and additional insertion of titanium mesh in 12. The distal anchor went down to L5 in 4 patients, S1 in 12, and S2 in 9. Preoperative scoliosis of 38 degrees +/- 12 degrees was corrected to 15 degrees +/- 8 degrees (60% correction) at most recent follow-up, and preoperative kyphosis of 35 degrees +/- 25 degrees was corrected to -5 degrees +/- 11 degrees (40 degrees correction). The compensatory coronal curve of 26 degrees was spontaneously corrected to 12 degrees at most recent follow-up. The preoperative thoracic lordosis of -16 degrees was corrected to 4 degrees at most recent follow-up, and the preoperative lumbar kyphosis of 20 degrees was corrected to -17 degrees . Preoperative coronal imbalance of 2.0 cm was improved to 0.9 cm at most recent follow-up, and preoperative sagittal imbalance of 9.3 cm was improved to 4.6 cm. Mean operation time was 280 minutes with a blood loss of 2,810 mL. The preoperative neurologic compromise was improved in all patients, and pain was reduced to less than half of preoperative visual analog analog scale in 17 patients. The following complications were encountered in 5 patients: 2 with transient neurology that spontaneously improved without a sequel within 6 months, 2 with compression fractures at proximal adjacent vertebra, and 1 with pseudarthrosis. CONCLUSIONS PVCR is an effective procedure for the management of fixed lumbosacral deformity. It provides satisfactory correction and improved functional outcomes. However, it is a technically demanding and exhausting procedure with possible risks for complications.

STUDY DESIGN Retrospective study. OBJECTIVES To evaluate outcomes of selective thoracic fusion with segmental pedicle screw fixation in thoracic idiopathic scoliosis with a minimum 5-year follow-up. SUMMARY OF BACKGROUND DATA Segmental pedicle screw fixation has been proven to enable true segmental control and greater correction both in coronal and sagittal planes of scoliosis. However, there is no long-term study of selective thoracic fusion with segmental pedicle screw fixation in thoracic idiopathic scoliosis. METHODS Two hundred and three thoracic idiopathic scoliosis patients with 236 thoracic curves subject to selective thoracic fusion with segmental pedicle screw fixation were analyzed. Mean patient age at the time of operation was 13.8 years (range: 8.9-18). RESULTS The preoperative thoracic curve of 51 +/- 12 degrees was corrected to 16 +/- 7 degrees (69% correction, 3% loss of correction) at the most recent follow-up. The noninstrumented lumbar curve of 30 +/- 10 degrees was corrected to 10 +/- 8 degrees (66% correction, 5% loss of correction) at the most recent follow-up. The preoperative thoracic kyphosis of 18 +/- 11 degrees and the lumbar lordosis of 43 +/- 10 degrees were improved to 23 +/- 8 degrees and 46 +/- 9 degrees , 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 2,867 thoracic pedicle screws inserted in 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 in thoracic idiopathic scoliosis had satisfactory radiographic and clinical outcomes after surgery and has been well-maintained for minimum 5-year follow-up. It is a safe and effective method for preservation of lumbar motion segments as well as for restoration and maintenance of both coronal and sagittal alignment.

Study design Retrospective study. Objective To report on the technique and results of posterior vertebral column resection (PVCR) for severe rigid scoliosis. Summary of background data The treatment of severe rigid scoliosis is a demanding surgical challenge. Conventional procedures such as combined anteroposterior instrumentation enable limited correction. In rigid scoliosis, vertebral column resection is a better option for accomplishing translation of spinal column. PVCR is performed through a single posterior approach. Methods A total of 16 patients with scoliosis (average age 29 years) subjected to PVCR were retrospectively reviewed after a minimum follow-up of 2 years (range 2-6.8). The indication for PVCR was scoliosis more than 80 degrees , with flexibility less than 25%. The radiographic parameters were evaluated, and clinical records were reviewed. Results The number of vertebrae removed averaged 1.3, and 21 total (15 thoracic and 6 lumbar). Average fusion extent was 10.6 vertebrae. The mean preoperative scoliosis of 109.0 degrees was corrected to 45.6 degrees (59% correction) at the most recent follow-up, and the minor curve of 59.3 degrees was corrected to 29.2 degrees (51% correction). The mean preoperative coronal imbalance of 4.0 cm was improved to 1.0 cm at the most recent follow-up, and sagittal imbalance of 4.2 cm was improved to 1.6 cm. Complications were encountered in 4 patients, including 1 complete paralysis, 1 hematoma, 1 hemopneumothorax, and 1 proximal junctional kyphosis. Conclusions PVCR is an effective alternative for severe rigid scoliosis. It is a highly technical procedure and should only be performed by an experienced surgical team.

STUDY DESIGN A retrospective study was conducted. OBJECTIVE To determine the exact distal fusion level in the treatment of single thoracic idiopathic scoliosis (King Types 3 and 4) with segmental pedicle screw fixation. SUMMARY OF BACKGROUND DATA Pedicle screw fixation effectively shortens the distal fusion extent by improved three-dimensional deformity correction. However, the selection of distal fusion extent remains controversial in single thoracic idiopathic scoliosis. METHODS This study analyzed 42 patients with single thoracic adolescent idiopathic scoliosis (32 King 3 patients and 10 King 4 patients) who underwent segmental pedicle screw fixation and had a minimum follow-up period of 2 years (range, 2-6 years). The patients were grouped according to the distal fusion level with reference to the standing neutral rotated vertebra (NV) for comparison of deformity correction and spinal balance using standing radiographs. Failure to restore an adequate trunk balance and progression or extension of the primary curve (adding on) was considered unsatisfactory. RESULTS Preoperative 50 degrees +/- 11 degrees of thoracic deformity was corrected to 13 degrees +/- 5 degrees, for a curve correction of 74%. Preoperative 23 degrees +/- 7 degrees of lumbar deformity was corrected to 2 degrees +/- 8 degrees, for a curve correction of 93%. Curve correction was not significantly affected by King type or distal fusion level (P > 0.05). Postoperative unsatisfactory results were obtained in 14 patients. When the preoperative NV was the same or one level distal to end vertebra (EV), fusion down to NV was satisfactory (14/14). When the preoperative NV was more than two levels distal to EV, fusion down to one level shorter than NV (NV-1) also was satisfactory (9/9). However, when fusion down to NV-2 or shorter was performed, the chances of adding on were higher (14/19; P < 0.01). Preoperative 17 degrees +/- 8 degrees of thoracic kyphosis was improved to 24 degrees +/- 7 degrees. CONCLUSIONS In single thoracic idiopathic scoliosis, NV is an important factor for the determination of fusion level. When preoperative NV and EV show no more than two-level gap differences, the curve should be fused down to NV. When the gap is more than two levels, fusion down to NV-1 is satisfactory, saving one or two motion segments, as compared with fusion extending to the stable vertebra.

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

Purpose : To report a technique of vertebral column resection using a single posterior approach and its results in the treatment of severe spinal deformities. Materials and Methods : Seventy spinal deformity patients treated by posterior vertebral column resection (PVCR) were retrospectively reviewed with minimum follow up of 2 years (2-3.3 years). There were 34 males and 36 females with a mean age of 27.4 years. Etiologic diagnoses were; adult scoliosis in 7, congenital kyphoscoliosis in 38, and post-infectious kyphosis in 25. The surgery consisted of temporary stabilization of the vertebral column with segmental pedicle screw fixation, resection of the vertebral column at the apex of the deformity via the posterior route followed by gradual deformity correction and fusion. Radiological and clinical data were reviewed for deformity correction and clinical results. Results : The total number of resected vertebrae were 143; 76 thoracic and 67 lumbar. Mean operation time was 4 hours 31 minutes with an average blood loss of 2,333 mL. The deformity correction was 62.9% in the coronal plane and in the sagittal plane. Complications were encountered in 24 patients; 2 complete cord injuries in severe adult scoliosis and a single thoracic kyphosis patient who had significant preoperative cord compromise, 6 hematomas, 4 root injuries (all incomplete), 5 fixation failures, 2 infections and 5 hemopneumothoraxes. Conclusion : PVCR is an effective alternative for severe fixed spinal deformities. However, extreme caution must be taken in patients with preoperative cord compromise who have a high risk of neurological complications.

Purpose: To analyze surgical outcomes of thoracolumbar and lumbar scoliosis treated with segmental pedicle screw fixation, and to determine the exact distal fusion level. Materials and Methods: Seven idiopathic thoracolumbar and lumbar scoliosis patients (6 thoracolumar and 1 lumbar scoliosis, 7 females with mean age of 15.9 years) subjected to segmental pedicle screw fixation with a minimum follow-up of 2 years were retrospectively analyzed for deformity correction, stable vertebra, lower instrumeted vertebral tilt (LIVT) and coronal balance using pre and post-operative standing radiographs. The bending stable vertebra and the rotational correction of L3 were measured in preoperative bending radiographs. The L3 rotation in the bending radiographs was less than Nash-Moe grade II in all patients. The bending stable vertebra was L3 in 4 patients and L4 in 3. An unsatisfactory result was defined as an LIVT of more than or a coronal imbalance of more than 10 mm. Results: Distal fusion went down to L3 in 6 patients and L4 in one patient whose bending stable vertebra had been L4 preoperatively. The preoperative average major curve of was corrected to (81% correction). The preoperative average thoracic curve of and the average lumbosacral curve of were corrected to and , respectively. Two patients with distal fusion to L3 showed unsatisfactory results; LIVT was more than in both patients and coronal imbalance more than 10 mm in one. Both the patients had bending stable vertebra of L4 preoperatively. Conclusion: In the correction of thoracolumbar and lumbar scoliosis with segmental pedicle screw fixation, the curve could be fused to L3 when the L3 rotation in the bending radiograph was less than Nash-Moe grade II and the bending stable vertebra was L3.

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.