Pedicle Subtraction Osteotomy Group Research Articles

Finite element study on three osteotomy methods for treating thoracolumbar osteoporotic fracture vertebral collapse complicated with neurological dysfunction.

Surgical methods for patients with osteoporotic fracture vertebral collapse complicated with neurological dysfunction are still a topic of debate. We designed an improved osteotomy for the treatment of osteoporotic compression fracture patients with neurological dysfunction. Compared with traditional osteotomy methods such as pedicle subtraction osteotomy (PSO) and bone-disc-bone osteotomy (BDBO), the osteotomy range is reduced. Therefore, we use a finite element method to analyze the biomechanical conditions of these three osteotomy methods and provide a mechanical theoretical basis for the surgical treatment of these three osteotomy methods. Based on the CT scan of a patient with L1 osteoporotic fracture vertebral collapse and neurological dysfunction, the finite element model was constructed by importing Mimics software, and three different osteotomy models were established. The forces and displacements of internal fixation device, T1-L5 whole segment, T10 vertebral body, and T10/11 intervertebral disc were recorded under different working conditions. The displacement levels of internal fixation device, T1-L5 spine, T10 vertebral body, and T10/11 intervertebral disc in the modified osteotomy group were between BDBO group and PSO group. The stress in BDBO group was concentrated in titanium mesh and its maximum stress was much higher than that in PSO group and modified osteotomy group. The mechanical distribution of T10/11 intervertebral disc showed that the maximum stress distribution of the three osteotomy methods was similar. The relatively simple modified osteotomy has certain advantages in stress and displacement. In contrast, the stability of BDBO group was poor, especially in the lumbar intervertebral disc and lumbar body. For this type of osteotomy patients, it is recommended to avoid postoperative flexion so as not to increase the load.

Comparison of staged lateral lumbar interbody fusion combined two-stage posterior screw fixation and two osteotomy strategies for adult degeneration scoliosis: a retrospective comparative study

AimsThe commonly used treatments of adult degeneration scoliosis (ADS) were posterior long segment screw fixation with osteotomies. Recently, lateral lumbar intervertebral fusion combined two-stage posterior screw fixation (LLIF + PSF) as a new strategy without osteotomy. Herein, this study aimed to compare the clinical and radiological outcomes among LLIF + PSF and pedicle subtraction osteotomy (PSO), posterior column osteotomies (PCO).MethodsTotals of 139 ADS patients underwent operation with 2 years longer follow-up visit between January 2013 and January 2018 in Ningbo No.6 Hospital were enrolled into this study. 58 patients were included in PSO group, 45 in PCO group and 36 in LLIF + PSF group, The clinical and radiological data were reviewed from medical records. Baseline characteristic, perioperative radiological data (sagittal vertical axis (SVA), coronal balance (CB), Cobb angle of Mian curve (MC), Lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence-lumbar lordosis mismatch (PI-LL)), clinical outcomes (VAS of back and leg, Oswestry disability index (ODI) and Scoliosis Research Society 22-question Questionnaire (SRS-22)) and complications were evaluated and compared.ResultThere were no significantly difference in baseline characteristics, preoperative radiological parameters and clinical outcomes among three groups. LLIF + PSF group was significantly shorter in operation time than other two groups (P < 0.05), whereas significant longer hospital stay was observed in LLIF + PSF group (P < 0.05). As for radiological parameters, LLIF + PSF group had significantly improvement in SVA, CB, MC, LL and PI-LL (P < 0.05). Moreover, LLIF + PSF group achieved significantly less correction loss in SVA, CB and PT than PSO and PCO group (1.5 ± 0.7 VS 2.0 ± 0.9 VS 2.2 ± 0.8, P < 0.05; 1.0 ± 0.4 VS 1.3 ± 0.5 VS 1.1 ± 0.7, P < 0.05 and 4.2 ± 2.8 VS 7.2 ± 3.1 VS 6.0 ± 2.8, P < 0.05). Significantly recovery in VAS of back and leg, ODI score and SRS-22 were found among all groups, however, LLIF + PSF shown significant better clinical therapy maintain at follow-up visit than other two groups (P < 0.05). There were no significantly difference in complications among groups (P = 0.66).ConclusionLateral lumbar interbody fusion combined two-stage posterior screw fixation (LLIF + PSF) can achieve comparable clinical therapy for adult degeneration scoliosis as osteotomy strategies. However, furthermore more studies need be taken for verifying the effect of LLIF + PSF in the future.

Comparison of pedicle subtraction osteotomy and vertebral column decancellation for the correction of thoracolumbar kyphotic deformity in ankylosing spondylitis: a systematic review and meta-analysis.

The goal in this study was to compare the efficacy and safety outcomes of vertebral column decancellation (VCD) and pedicle subtraction osteotomy (PSO) for patients with ankylosing spondylitis (AS) with thoracolumbar kyphotic deformity. This study was registered on the International Prospective Register of Systematic Reviews (PROSPERO). The authors conducted a computer search of PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan Fang Database, and Wei Pu Database to collect controlled clinical studies on the efficacy and safety of VCD and PSO for patients with AS with thoracolumbar kyphotic deformity. The search covered the period from database establishment to March 2023. Two researchers screened the literature, extracted data, and evaluated the risk of bias of the included studies; these researchers recorded the authors and the sample size, and they extracted data on the intraoperative blood loss, Oswestry Disability Index, spine sagittal parameters, operation time, and complications in each study. Meta-analysis was performed using RevMan 5.4 software provided by Cochrane Library. A total of 6 cohort studies with a total of 342 patients were included in this study, including 172 patients in the VCD group and 170 patients in the PSO group. The VCD group had lower intraoperative blood loss than the PSO group (mean difference [MD] -274.92, 95% CI -506.63 to -43.20, p = 0.02); significant correction of the sagittal vertical axis compared with the PSO group (MD 7.32, 95% CI -1.24 to 15.87, p = 0.03), and the operation time was shorter than that of the PSO group (MD -80.28, 95% CI -150.07 to -10.48, p = 0.02). This systematic review and meta-analysis showed that VCD had more advantages than PSO in correcting the sagittal imbalance in the treatment of AS with thoracolumbar kyphotic deformity, and VCD had less intraoperative blood loss, shorter operation time, and satisfactory results in improving the quality of life.

Center of rotation analysis for thoracic and lumbar 3-column osteotomies in patients with sagittal plane spinal deformity: insights in geometrical changes can improve understanding of correction mechanics.

Three-column osteotomy (3CO) is used for severe spinal deformities. Associated complications include sagittal translation (ST), which can lead to neurological symptoms. Mismatch between the surgical center of rotation (COR) and the concept of the ideal COR is a potential cause of ST. Matching surgical with conceptual COR is difficult with pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR). This mismatch influences correction geometry, which can prevent maximum possible correction. The authors' objective was to examine the sagittal correction geometry and surgical COR of thoracic and lumbar 3CO. In a retrospective study of patients with PSO or VCR for severe sagittal plane deformity, analysis of surgical COR was performed using pre- and postoperative CT scans in the PSO group and digital radiographs in the VCR group. Radiographic analysis included standard deformity measurements and regional kyphosis angle (RKA). All patients had 2-year follow-up, including neurological outcome. Preoperative CT scans were studied for rigid osteotomy sites versus mobile osteotomy sites. Additional radiographic analysis of surgical COR was based on established techniques superimposing pre- and postoperative images. Position of the COR was defined in a rectangular net layered onto the osteotomy vertebrae (OVs). The study included 34 patients undergoing PSO and 35 undergoing VCR, with mean ages of 57 and 29 years and mean RKA corrections of 31° and 49°, respectively. In the PSO group, COR was mainly in the anterior column, and surgical and conceptual COR matched in 22 patients (65%). Smaller RKA correction (27° vs 32°, p = 0.09) was seen in patients with anterior eccentric COR. Patients with rigid osteotomy sites were more likely to have an anterior eccentric COR (41% vs 11%, p = 0.05). In the VCR group, 20 patients (57%) had single-level VCR and 15 (43%) had multilevel VCR. COR was mainly located in the anterior or middle column. Mismatch between surgical and conceptual COR occurred in 24 (69%) patients. Larger RKA correction (63° vs 45°, p = 0.03) was seen in patients with anterior column COR. Patients with any posterior COR had a smaller RKA correction compared to the rest of the patients (42° vs 61°, p = 0.007). Matching the surgical with the conceptual COR is difficult and in this study failed in one- to two-thirds of all patients. In order to avoid ST during correction of severe deformities, temporary rods, tracking rods, or special instruments should be used for correction maneuvers.

L5 pedicle subtraction osteotomy maintains good radiological and clinical outcomes in elderly patients with a rigid kyphosis deformity: a more than 2-year follow-up report.

L5 pedicle subtraction osteotomy (PSO) is a demanding technique; thus, PSOs are usually performed at the L3/L4 level to correct the lack of lumbar lordosis. Mid- to long-term improvements in clinical outcomes after L5 PSO are unknown. We aimed to determine the efficacy and safety of L5 PSO for rigid kyphosis deformities. We retrospectively reviewed the records of 57 patients with a rigid kyphosis deformity (mean age: 68years) who underwent extensive corrective surgery incorporating PSO with a > 2-year follow-up. Radiographic parameters, postoperative complication rates, and the Oswestry Disability Index (ODI) scores were compared in the L5, L4, and L1-3 PSO groups preoperatively and at 1, 2, and 5years postoperatively. There were 12, 25, and 20 patients in the L5, L4, and L1-3 PSO groups, respectively. Significant between-group differences were found in preoperative L4-S1 lordosis (L5:L4:L1-3 PSO groups = - 8.9°:8.9°:16.2°, P < 0.001). The surgeries improved the postoperative spinopelvic alignment (similar in all groups). There was no significant between-group difference in the postoperative complication rate; no irreversible complications occurred. In the L5 PSO group, there was one case of a common iliac vein injury. The ODI scores improved postoperatively in all groups; this was maintained for 5years postoperatively. L5 PSO for L4-5/L5 kyphosis deformities resulted in adequate correction and ODI improvement, which were maintained up to 5years postoperatively. The surgical invasiveness, complication rates, and long-term prognosis associated with L5 PSO were similar to those of PSOs performed at other levels.

Choice of osteotomy methods for old thoracolumbar osteoporotic fracture with kyphosis

To investigate the clinical outcome of single or double-segment pedicle subtraction osteotomy (PSO) for the treatment of old thoracolumbar osteoporotic compression fractures with kyphosis. The clinical data of 26 patients with old thoracolumbar osteoporotic compression fractures with kyphosis who underwent surgery from January 2015 to June 2017 were retrospectively analyzed. There were 12 males and 14 females, aged from 58 to 72 years old with an average of 65.6 years. The time interval from fracture to surgery was (8.2±1.5) years. According to different surgical methods, the patients were divided into single-segment PSO group (group A) and double-segment PSO group(groupB). The perioperative data, preoperative and postoperative imaging data and postoperative complications were recorded, and the Oswestry Disability Index (ODI) and visual analogue scale (VAS) were used before and after surgery to evaluate the clinical effect. All patients were followed up for 6-24 months with an average of 14.5 months. There was a statistically significant difference in operation time and intraoperative blood loss between the two groups (P<0.05). There was no significant difference in total drainage volume and length of hospital stay (P>0.05). The postoperative correction angle of the single segment PSO group was (33.3± 9.4) ° with the correction rate of 85.3% and the double segment PSO group was (41.0±13.5) ° with the correction rate of 92.7%, and there was statistical significance between two groups (P<0.05). There were no significant differences in postoperative lumbar lordosis (LL), sagittal vertical axis (SVA), and ODI, VAS between two groups (P>0.05). One case of cone injury occurred in the single-segment PSO group and recovered after treatment. There were no complications of spinal cord injury in the double segment group. Loose screws occurred during surgery in three patients in the single-segment PSO group and one patient in the double-segment PSO group (P<0.05). All 4 patients were re inserted with screws after using bone cement to reinforce the nail pathway. There were no complications such as anterior spinal vascular and nerve damage or osteotomy unfusion. Both single-segment PSO and double-segment PSO can achieve good orthopedic and clinical effects in the treatment of old thoracolumbar osteoporotic fractures with kyphosis. For patients with correction angles greater than 40° , the double-segment PSO provides a better correction angle and is safer, but it is with longer operation time and more intraoperative bleeding.

70. Anterior column realignment (ACR) performed at L2-3 achieves suboptimal lumbo-pelvic realignment compared with L2 pedicle subtraction osteotomy (PSO)

BACKGROUND CONTEXT The anterior column realignment (ACR) technique is increasingly becoming popular for treating patients with flatback deformity. The degreed of correction achieved with ACR performed at L2-3 disc has not been well studied. PURPOSE The purpose of this study was to compare the degree of deformity correction and perioperative outcomes between ACR and PSO being performed at L2 for iatrogenic flatback deformity. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE N = 27 patients, 9 ACR and 18 PSO. The patients were matched 1:2 (ACR:PSO) based on preoperative deformity parameters. OUTCOME MEASURES Primary outcome: Lumbo-pelvic parameters (LL-PI mismatch, SVA, PT). Secondary outcomes: estimated blood loss, transfusion requirement, length of hospital stay, operative time, postoperative complication, and hospital readmission rates. METHODS Patients were identified between 2012 and 2016 who underwent revision surgery using either the PSO or ACR technique at the L2-3 level to correct sagittal deformity. Patients who underwent ACR were matched to PSO patients in a 1:2 fashion based on preoperative lumbar lordosis (LL) and lumbar lordosis pelvis incidence (LL-PI) mismatch. Patient demographics, surgical variables, pre- and postoperative radiographic parameters, and perioperative characteristics were compared between the treatment groups using t-tests, chi-square tests, and multivariable regression models. RESULTS The cohort included 27 patients; 9 ACR patients matched to 18 PSO patients. The PSO group achieved a greater degree of lumbar lordosis compared to the ACR group (31° vs 14.23°, p CONCLUSIONS PSO surgery resulted in significantly improved lumbar lordosis and sagittal alignment correction compared to the ACR group. While ACR resulted in some improvement of lumbar lordosis, it resulted in residual lumbo-pelvic mismatch compared with patients treated with PSO. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Efficacy comparison of multi-segment and single-segment osteotomy for old osteoporotic vertebral compression fracture combined with kyphosis

Objective To investigate the sagittal correction effect and clinical efficacy of multi-segment Smith-Peterson osteotomy (SPO) and single-segment pedicle subtraction osteotomy (PSO) in the treatment of old osteoporotic vertebral compression fracture (OVCF)combined with kyphosis. Methods A retrospective case control study was conducted to analyze the clinical data of 24 patients with old OVCF combined with kyphosis admitted to Traditional Chinese Medical Hospital of Xiaoshan from February 2014 to July 2016. There were 10 males and 14 females, aged 58-72 years, with an average of 65.6 years. Thirteen patients were treated with multi-segment SPO (Group A), six of whom underwent two-segment SPO and seven underwent three-segment SPO. Eleven patients were treated with single-segment PSO (Group B). The operation time, intraoperative bleeding volume, the number of cases using cement-reinforced nail track, postoperative drainage, hospitalization time and postoperative complications were compared between the two groups. Cobb angle, sagittal vertical axis (SVA), thoracic kyphosis angle (TK) and lumbar lordosis angle (LL) of kyphosis deformity were measured before operation, after operation and at the last follow-up. Oswestry Dysfunction Index (ODI) and Visual Analogue Scale (VAS) were used to evaluate the clinical efficacy at the last follow-up. Results All patients were followed up for 6-24 months, with an average of 15.4 months. The operation time of Group A was (198.1±27.3)minutes, while that of Group B was (237.6±36.1)minutes (P 0.05). Three patients in Group A and one patient in Group B had cerebrospinal fluid leakage (P 0.05). There was no significant difference in SVA, Cobb angle, TK and LL between the two groups at the last follow-up (P>0.05). There was no significant difference in ODI and VAS between the two groups after operation and at the last follow-up (P>0.05). No complications such as spinal cord injury, embolism caused by cement leakage, extraction or rupture of pedicle screw occurred in either group. Conclusion For old osteoporotic vertebrae compressed fractures combined with kyphosis, multi-segment SPO and single-segment PSO can achieve good sagittal correction and clinical efficacy. Single-segment PSO has better correction effect and lower incidence of cerebrospinal fluid leakage, yet accompanied with disadvantages of overcorrection, screw loosening, longer operation time and more blood loss. Key words: Osteoporotic fractures; Thoracic vertebrae; Lumbar vertebrae; Kyphosis; Osteotomy

Efficacy comparison of two posterior osteotomy methods for old thoracolumbar compressive fracture accompanied with kyphotic deformity

Objective To compare the clinical efficacy of pedicle subtraction osteotomy(PSO) and posterior unilateral vertebral column resection (PUVCR) for old thoracolumbar compressive fracture accompanied with kyphotic deformity. Methods A retrospective case control study was conducted to analyze the clinical data of 51 patients with old thoracolumbar fracture accompanied with kyphotic deformity admitted to the Third Hospital of Hebei Medical University from January 2010 to January 2016. There were 29 males and 22 females, aged 46-69 years, with an average age of 54.9 years. In terms of the injured segments, there were 11 patients with T11, 10 with T12, 17 with L1, and 13 with L2. A total of 22 patients were treated with traditional PSO (PSO group), and 29 patients PUVCR (PUVCR group). The operation time, intraoperative blood loss, hospital stay, Cobb angle improvement 2 weeks after operation and postoperative 1 year, visual analogue scale (VAS) 1 year after operation and Japanese Orthopedic Association (JOA) scores were compared between the two groups. Intraoperative and postoperative complications were recorded. Results All patients were followed up for 3-18 months, with an average of 13.5 months. There were no significant differences between PSO group and PUVCR group in hospital stay [(13.8±1.1)days vs. (14.1±1.2)days], thoracolumbar Cobb angle 2 weeks after operation [(8.3±1.5)° vs. (9.1±2.0)°] and JOA scores [(26.2±1.2)points vs. (25.5±1.5)points] (P>0.05). Significant differences were found between PUVCR group and PSO group in operation time [(184.9±22.9)minutes vs. (219.9±17.1)minutes], intraoperative blood loss [(911.5±70.2)ml vs. (1136.1±92.0)ml], Cobb angle 1 year after operation [(10.0±1.6)° vs. (12.7±1.9)°], and VAS 1 year after operation [(2.3±0.5)points vs. (2.9±0.7)points](P<0.05). No serious complications occurred during operation and follow-up. Conclusions For old thoracolumbar compressive fracture accompanied with kyphotic deformity, PSO and PUVCR can both effectively improve kyphosis and relieve dysfunction. But PUVCR has the advantages of shorter operation time, less intraoperative blood loss, better-improved kyphosis, and lower incidence of spinal nerve injury. Key words: Osteotomy; Spinal fractures; Kyphosis

Comparison of 2 Surgeries in Correction of Severe Kyphotic Deformity Caused by Ankylosing Spondylitis: Vertebral Column Decancellation and Pedicle Subtraction Osteotomy

To compare the treatment results between 1-level vertebral column decancellation (VCD) and pedicle subtraction osteotomy (PSO) for correcting severe kyphotic deformity in ankylosing spondylitis (AS). VCD and PSO have been used to correct AS-related kyphotic deformity, but the differences on correcting results between VCD and PSO are not clear. Between 2013 and 2015, 57 patients underwent 1-level spinal osteotomy (VCD: n= 30; PSO: n= 27) for correcting kyphotic deformity. Sagittal parameters, fusion results, surgical information, and clinical outcomes were documented and compared. All data were obtained before and 1 week after surgery, 6 months after surgery, and at final follow-up (at least 2 years). VCD provided significantly greater osteotomy angle (50.8° ± 9.7°) than PSO (38.5° ± 6.1°). In the VCD group, the change of the anterior column was 5.0 ± 1.3 mm, which was larger than the PSO group. The middle column was shortened by 9.9 ± 2.0 mm and 19.1 ± 3.3 mm in the VCD group and PSO group, respectively. There was no significant difference in operating time and blood loss between the 2 groups. All cases had solid fusion. Between the 2 groups, Scoliosis Research Society Outcomes Instrument-22 scores were similar at the final follow-up. No major acute complications occurred in both groups. VCD is a safe and effective method in treating rigid kyphotic deformity secondary to AS. VCD provides a larger correction angle in one segment and preserves more height of osteotomized vertebrae than PSO.

Is It Possible to Correct Congenital Spinal Deformity Associated With a Tethered Cord Without Prophylactic Intradural Detethering?

Patients who have a congenital spinal deformity with a tethered cord generally are treated with prophylactic intradural detethering before deformity correction. However, the detethering procedure carries substantial risk, and it is not clear whether deformity correction can be performed without detethering. To determine the (1) correction rate, (2) proportion of patients who experienced complications after surgery, and (3) neurological status after recovery from surgery in a group of patients with congenital spinal deformity and a tethered cord who were treated either with posterior spinal fusion only (PSF), pedicle-subtraction osteotomy (PSO), or a vertebral column resection (VCR), based on an algorithmic approach. Between 2006 and 2016, we treated 50 patients surgically for a congenital spinal deformity and a tethered cord. We defined a congenital spinal deformity as one that was caused by failure of vertebral segmentation, failure of vertebral formation, or both, and we made the diagnosis of a tethered cord based on a conus medullaris lower than L2 level, or a diameter of the filum terminale greater than 2 mm, as shown on magnetic resonance image. Of those, nine patients were lost to followup before the 2-year minimum, leaving 41 for analysis at a mean followup of 47 months (range, 24 to 92 months) in this single-institution retrospective study. The treatment algorithm involved one of three approaches: PSF, PSO, or VCR. A total of 15 patients underwent PSF; we used this approach for patients with moderate curves (Cobb angle < 80°) and intact neurological status both previously and during a bending and traction test. Eleven patients underwent PSO; we performed PSO when patients had neurological symptoms (in daily life or during the traction/bending test) and a magnitude of the curve less than 80°. Finally, 15 patients underwent VCR, which we used in patients with a magnitude of the curve more than 80° and/or flexibility less than 20%, with/without neurological symptoms. No patient in any group underwent intradural detethering. We report on the correction rate, defined as the ratio between the corrected magnitude and preoperative magnitude of a curve at a given postoperative time point (correction rate = 1- (Cobb angle at a given time point/preoperative Cobb angle) x 100%); complications, that is, postoperative/recurrent neurological symptoms, cerebrospinal fluid leakage, infection, blood loss > 5000 mL, as determined by chart review performed by an individual not directly involved in patient care; and a detailed neurological exam, including evaluations of sensory function, extremity muscle strength, pain, gait, physiological reflexes, and pathological signs, both before surgery and at most recent followup, as performed by the surgeon. All neurologically symptomatic patients were evaluated with a neurologic scoring system. The overall mean ± SD correction rate in this series was 63% ± 14%. It was 70% ± 12% in the PSF group, 64% ± 17% in the PSO group, and 56% ± 12% in the VCR group. Seven patients in those three groups experienced major complications, including blood loss more than 5000 mL, temporary neurological symptoms, cerebrospinal fluid leakage, and infection. The most severe complications included one patient in the VCR group who had temporarily decreased strength in the lower limb, and one patient in the PSO group with temporary numbness in the lower limb. Finally, no patients in PSF group had postoperative neurological complications, and all patients with neurological symptoms in the PSO/VCR group improved to varying degrees. For neurologically symptomatic patients in PSO group (n = 6), the neurological score improved slightly, from 22.5 ± 1.9 preoperatively to 24.2 ± 0.8 at the most recent followup (p = 0.024) with a mean difference of 1.7. For neurologically symptomatic patients in VCR group (n = 10), the neurological score improved slightly from 23.1 ± 1.1 preoperatively to 24.2 ± 0.6 at most recent followup (p = 0.009) with a mean difference of 1.1. Congenital spinal deformity with a tethered cord may be treated without prophylactic intradural detethering. In the current series treated according to this treatment algorithm, good correction and neurological improvement were achieved, and few complications occurred. However, such a small series cannot prove the safety of this treatment; for that, larger, multicenter studies are necessary. Level IV, therapeutic study.

Pedicle Subtraction Osteotomy Versus Multiple Posterior Column Osteotomies in Severe and Rigid Neuromuscular Scoliosis.

Retrospective analysis. The aim of this study is to compare the safety and efficacy of the apical pedicle subtraction osteotomy (PSO) technique with multiple posterior column osteotomies (PCOs) in nonambulatory patients with severe, rigid neuromuscular scoliosis. Neuromuscular scoliosis frequently causes intolerance to sitting due to pelvic obliquity, trunk decompensation, and associated back and rib impingement pain which diminish the patient's functional capacity. In the case of rigid curves, spinal osteotomy techniques are occasionally required for effective correction. We retrospectively reviewed our patients with severe and rigid neuromuscular scoliosis with associated pelvic obliquity who were treated with posterior instrumented fusion extending to pelvis with more than 1-year postoperative follow-up. We compared radiological and clinical results of PSO and multiple PCO techniques in severe rigid neuromuscular scoliosis with pelvic obliquity of more than 15° in traction radiograph under general anesthesia. Hospital records were also reviewed for operative time, intraoperative blood loss, amount of blood transfusion, duration of hospital stay, and complications. There were 12 patients in the PSO group and 10 patients in the PCO group. There was no significant difference between groups in terms of major curve magnitude, sagittal parameters or pelvic obliquity. Although not statistically significant, PSO technique did trend toward better scoliosis correction (post-op Cobb angle 56.1° vs. 66.7° [P = 0.415]). PSO technique provided a significantly better correction in pelvic obliquity (59% vs. 84%) (P = 0.001). There was no significant difference in average intraoperative blood loss, transfusion, and operative times including anesthesia time, hospital stay, or complications. PSO may be an option in correction of severe and rigid neuromuscular scoliosis. It provides better correction of pelvic obliquity without increasing operative time, need for transfusion, or duration of hospitalization as compared to multiple apical PCO technique. Traction radiograph under general anesthesia is a valuable tool in surgical decision making. 4.

Pedicle Subtraction Osteotomy with a Cage Prevents Sagittal Translation in the Correction of Kyphosis in Ankylosing Spondylitis.

Background:Sagittal translation (ST) is an accidental event that surgeons commonly encounter during a spinal osteotomy in the correction of kyphosis in ankylosing spondylitis (AS). However, there is a paucity of effective techniques to prevent ST. The purpose of this study was to propose a pedicle subtraction osteotomy (PSO) with a cage as a method to prevent ST and to explore the efficacy and feasibility of this method in the treatment of kyphosis in AS.Methods:We retrospectively reviewed 89 consecutive patients with AS kyphosis who underwent a PSO (Group B, 46 patients) or a PSO with a cage (Group A, 43 patients) from February 2009 to December 2013. Pre- and post-operative radiographic results were reviewed. ST and complications were analyzed in both groups. Clinical assessment was performed using the Scoliosis Research Society-22 (SRS-22) outcomes metric. The patients were followed up for at least 2 years.Results:Group A achieved the same re-alignment of the kyphotic spine as Group B. Two (4.7%) of the 43 patients in Group A and 14 (30.4%) of the 46 patients in Group B had intraoperative ST (χ2 = 10.020, P = 0.002). Significant differences were identified between the two groups in the height change of the osteotomized column. SRS-22 scores improved significantly in both groups. Seven patients experienced neurologic complications (1 in Group A and 6 in Group B). Eight patients had cerebrospinal fluid leakage (2 in Group A and 6 in Group B).Conclusion:PSO with a cage significantly avoided ST during the osteotomy procedure and might represent a new, safe, and feasible choice for treating patients with AS kyphosis.

Spinopelvic Alignment by Different Surgical Methods in the Treatment of Degenerative Sagittal Imbalance of the Lumbar Spine

A retrospective comparative study. To compare pedicle subtraction osteotomy (PSO) and iliac fixation (ILF) without osteotomy as methods of correcting lumbar spine deformities due to degenerative sagittal imbalance (DSI) through the evaluation of the changes in spinopelvic alignment. Many papers have reported the surgical results after PSO and ILF for patients with fixed adult deformities. However, little is known about the difference between PSO and ILF corrections of spinopelvic alignment in adults with DSI. DSI patients who had undergone PSO or ILF with a minimum of 2-year follow-up (FU) were retrospectively studied in PSO (n=30) or ILF (n=25) groups. Lumbar lordosis (LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA) were measured as spinal parameters and pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were used as measurements of pelvic parameters. Clinical outcomes were evaluated using a visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores. There were no statistically significant differences between the PSO and ILF groups with regard to age and fused segments, but there were significant differences in operative time and estimated blood loss. Concerning spinal parameters, there were significant increases of LL and TK in PSO group immediate postoperatively (LL: P=0.014, TK: P=0.017) and at the 2-year FU (LL: P=0.021, TK: P=0.022), but no significant difference in SVA was evident between the 2 groups. Within the pelvic parameters, there was a significant increase of SS and decrease of PT in the ILF group immediate postoperatively (SS: P=0.013, PT: P=0.009) and at the 2-year FU (SS: P=0.024, PT: P=0.027), but the PI in both groups was not changed after surgery and there was no significant difference between 2 groups. VAS and ODI were significantly improved after surgery in both groups. The PSO group was better than the ILF group in the correction of the LL and TK, but not with regard to the pelvic parameters. The ILF group was superior in the correction of the pelvic orientation as compared with the PSO group when the PI was constant after surgery. Ultimately, ILF effectively achieves better correction of the pelvic parameters (SS and PT).

Sagittal Correction and Reciprocal Changes After Thoracic Pedicle Subtraction Osteotomy.

A retrospective clinical review. To evaluate the sagittal correction efficacy of a thoracic pedicle subtraction osteotomy (PSO), to determine and predict changes at both the cervical and lumbar mobile unfused segments after whether an upper or lower level thoracic PSO. Thoracic PSO is a technically challenging but increasingly valid procedure in the treatment of fixed thoracic deformities.Anatomical characteristics differentiate upper and lower segment thoracic PSOs and define its corrective ability. There is yet paucity in the literature concerning the causality between the osteotomy level and the reciprocal changes observed postoperatively at the adjacent unfused curves. Data collection from a single institutional database was carried out retrospectively by reviewing medical records and imaging of fixed thoracic kyphotic deformity patients submitted to a single level thoracic PSO. Seventeen patients (11M:6F), with a mean age of 44 years (range, 17-76). Fifty-nine percent had a previous spine surgery. The mean follow-up was of 55 months (range, 27-122). In six patients PSO was performed in the upper thoracic segment (T1-T6) and in 11 patients between T7 and T12 (lower thoracic segment), allowing a mean local kyphosis correction of 31° and 41° respectively. The mean cervical and lumbar lordosis globally improved. The upper thoracic PSO group had a significant improvement of the cervical lordosis with a mean C7 slope correction of 28° (P = 0.004), whereas in the lower thoracic PSO group a more pronounced correction of the maximal lumbar lordosis was observed (22°, P = 0.033). After a fixed sagittal thoracic deformity, the predominant lordotic compensation seems to occur at the nearest mobile curve from the deformity apex. The PSO-induced restoration of the thoracic kyphosis relieved the compensatory cervical and/or lumbar excessive lordosis, which were present preoperatively and are now no longer needed to achieve balance and maintain horizontal gaze. 4.

Walking sagittal balance correction by pedicle subtraction osteotomy in adults with fixed sagittal imbalance

Pedicle subtraction osteotomy (PSO) is widely used to treat severe fixed sagittal imbalance. However, the effect of PSO on balance has not been fully documented. The aim of this study was to assess dynamic walking balance after PSO to treat fixed sagittal imbalance. Gait and balance were assessed in 15 consecutive adult female patients who had been treated by PSO for a fixed sagittal imbalance and compare patients' preop and postop dynamic walking balance with that of 15 age- and gender-matched healthy volunteers (HV). Each patient's chart, X-rays, pre and postop SRS22 outcome scores, and ODI were reviewed. Means were compared by Mann-Whitney U test and Chi-square test. The mean age was 66.3years (51-74years). The mean follow-up was 2.7years (2-3.5years). The C7PL and GL, measured on the force platform, were both improved from 24.2±7.3cm and 27.6±9.4 to 5.4±2.6cm and 7.2±3.4cm, respectively. The baseline hip ROM was significantly smaller in patients compared to HV, whereas no significant difference was observed in the knee or ankle ROM. The pelvic tilt (preop -0.4°±1.4°, postop 8.9°±1.0°), and maximum hip-extension angle (preop -1.2°±14.2°, postop -11.2°±7.2°) were also improved after surgery. Cadence (116s/min), stance-swing ratio (stance 63.2% vs. swing 36.8%), and stride (98.0cm) were all increased after surgery. On the other hand, gait velocity was significantly slower in the PSO group at both pre and postop than in HV (PSO 53.3m/min at preop and 58.8m/min at postop vs. HV 71.1m/min, p=0.04). Despite a mild residual spinal-pelvic malalignment, PSO restored sagittal alignment and balance satisfactorily and has improved the gait pattern.

Mini-Open Anterior Lumbar Interbody Fusion Combined with Lateral Lumbar Interbody Fusion in Corrective Surgery for Adult Spinal Deformity.

Study DesignProspective observational study.PurposeTo introduce the techniques and present the surgical outcomes of mini-open anterior lumbar interbody fusion (ALIF) at the most caudal segments of the spine combined with lateral lumbar interbody fusion (LLIF) for the correction of adult spinal deformityOverview of LiteratureAlthough LLIF is increasingly used to correct adult spinal deformity, the correction of sagittal plane deformity with LLIF alone is reportedly suboptimal.MethodsThirty-two consecutive patients with adult spinal deformity underwent LLIF combined with mini-open ALIF at the L5–S1 or L4–S1 levels followed by 2-stage posterior fixation. ALIF was performed for a mean 1.3 levels and LLIF for a mean 2.7 levels. Then, percutaneous fixation was performed in 11 patients (percutaneous group), open correction with facetectomy with or without laminectomy in 16 (open group), and additional pedicle subtraction osteotomy (PSO) in 5 (PSO group). Spinopelvic parameters were compared preoperatively and postoperatively. Hospitalization data and clinical outcomes were recorded.ResultsNo major medical complications developed, and clinical outcomes improved postoperatively in all groups. The mean postoperative segmental lordosis was greater after ALIF (17.5°±5.5°) than after LLIF (8.1°±5.3°, p <0.001). Four patients (12.5%) had lumbar lordosis with a pelvic incidence of ±9° preoperatively, whereas this outcome was achieved postoperatively in 30 patients (93.8%). The total increase in lumbar lordosis was 14.7° in the percutaneous group, 35.3° in the open group, and 57.0° in the PSO group. The ranges of potential lumbar lordosis increase were estimated as 4°–25°, 23°–42°, and 45°–65°, respectively.ConclusionsMini-open ALIF combined with LLIF followed by posterior fixation may be a feasible technique for achieving optimal sagittal balance and reducing the necessity of more extensive surgery.

Will Immediate Postoperative Imbalance Improve in Patients with Thoracolumbar/Lumbar Degenerative Kyphoscoliosis? A Comparison between Smith–Petersen Osteotomy and Pedicle Subtraction Osteotomy with an Average 4 Years' Follow-Up

Introduction There was a paucity of literature paying attention to the postoperative imbalance after pedicle subtraction osteotomy (PSO) or Smith–Petersen osteotomy (SPO) and natural evolution of the imbalance. This study aims to compare compensatory behavior of coronal and sagittal alignment following PSO and SPO for degenerative kyphoscoliosis. Patients and Methods A retrospective study was performed on 68 consecutive patients with degenerative kyphoscoliosis treated by lumbar PSO (25 patients) or SPO (43 patients) procedures at a single institution. Long-cassette standing radiographs were taken preoperatively, postoperatively, and at last, follow-up and radiographic parameters were measured. The LIV and level of osteotomy were compared between the patients with and without improvement. Results Negative SVA was observed in PSO group postoperatively, implying an overcorrection of SVA. This negative SVA improved spontaneously during follow-up ( p &lt; 0.05). Coronal balance was found to worsen immediately post-op in the SPO group ( p &lt; 0.05). At the last follow-up, spontaneous improvement was observed in 15 patients and the average CB decreased to 16.35 mm. For the 15 patients with improved CB, fusion at L5 or above was more common compared with the 11 patients with persisted postoperative imbalance ( p = 0.027), whereas no difference in term of levels of osteotomy was found ( p &gt; 0.05). Conclusion The overcorrection of SVA is more often seen in PSO group. The coronal imbalance is more likely to occur in SPO group. The postoperative sagittal imbalance often spontaneously improves with time. LIV at S1 or with pelvic fixation should be regarded as potential risk factors for persistent coronal imbalance in patients with SPO.

Spinal osteotomy techniques in management of severe pediatric spinal deformity and analysis of postoperative complications.

Retrospective analysis. To compare radiographical analysis and clinical outcomes of spinal osteotomy techniques, including Smith-Petersen osteotomy (SPO), pedicle subtraction osteotomy (PSO), and vertebral column resection (VCR), and analyze the relationship between preoperative evaluation and postoperative complication incidence. These 3 techniques have been extensively reported previously, whereas, few literatures are available on comparing these 3 techniques in management of severe pediatric spinal deformity. In all the 34 pediatric patients, 14 were treated with SPO, 12 were treated with PSO, and 8 were treated with VCR. All operations were performed by the senior author (L. X.) between 2005 and 2009 in the Institute of Spinal Deformity, The First Affiliated Hospital of Zhengzhou University. Preoperative Halo-gravity traction was applied for 2 weeks in all patients; patients were evaluated by using standing radiographs taken before and after traction and after operation and a prospectively collected database with outcomes questionnaires. The postoperative complications and its relationship to preoperative assessment were also analyzed in this study. All the 34 patients' severe pediatric spinal deformity (22 females and 12 males) was diagnosed, with an average age of 11.97 years (range, 6-17 yr) and an average follow-up of 66.38 months (range, 48-97 mo). The mean preoperative major curve for each group was 103.43º in the SPO group, 108.08º in the PSO group, and 117.00º in the VCR group, and was corrected to 15.21º, 16.83º, and 25.88º, respectively. The apical vertebral translation was corrected by 73.29% by SPO, 73.35% by PSO, and 59.71% by VCR. The coronal balance was improved from 16.57 mm to 1.50 mm in the SPO group, 17.33 mm to 3.83 mm in the PSO group, and 29.38 mm to 3.63 mm in the VCR group. The mean correction of the kyphotic angle for single SPO was 19.00º, for those with 2 and 3 SPOs, the average correction was 34.40º and 47.5º, and 33.83º for the PSO group, 47.38º for the VCR group. There were significant improvements in the overall clinical outcomes. The overall complication rate was 35.3%. The complication rate was high in patients with respiratory insufficiency and rigid spine. There was no significant difference in coronal correction among these 3 techniques, whereas, the average corrections in the sagittal plane were progressively higher from single SPO to 2 SPOs or PSO to 3 SPOs or VCR. Preoperative respiratory insufficiency and rigidity of the spinal deformity are associated with a high complication rate. 3.

Comparison of sagittal reconstruction in ankylosing spondylitis patients with kyphosis: Smith-Petersen osteotomies versus pedicle subtraction osteotomy

Objective To compare the effects of Smith-Petersen osteotomies (SPOs) and pedicle subtraction osteotomy (PSO) on sagittal alignment in patients with thoracolumbar kyphosis secondary to anky losing spondylitis (AS).Methods The data of the 39 patients with ankylosing spondylitis of thoracic and lumbar kyphosis were retrospectively reviewed,who received SPOs or PSO orthopedic internal fixation from August 2000 to June 2010.According to the types of osteotomies,the 39 patients were categorized into 2groups.Of them,15 patients including 13 males and 2 females comprised the SPOs group,whose average age was 28.1±7.1 years,ranging from 18 to 42,whereas the other 24 patients including 20 males and 4 females comprised the PSO group,whose average age was 38.3±7.9 years,ranging from 21 to 53.Radiographic parameters were measured and compared between the two groups including thoracic kyphosis (TK),lumbar lordosis (LL),global kyphosis (GK),sagittal imbalance (SVA),pelvic incidence (PI),sacral slope (SS),and pelvic tilting (PT) before the operation,3 months after the operation,and at the last follow-up,respectively.Results Significant differences were found in terms of the improvement of LL,PT,SS,SVA and GK except that of TK and PI.Preoperatively,no significant difference was found between the two groups in TK,SVA,PT and SS except PI,GK and LL.Postoperatively,significant differences were found between the two groups in LL,GK,PT and SS.Significant differences were found between the two groups in the mean loss of correction of GK,LL,SVA,PT and SS at the last follow-up.Conclusion For patients with ankylosing spondylitis of thoracic and lumbar kyphosis,satisfactory reconstruction of spino-pelvic alignment can be obtained by PSO,whereas loss of correction occurred frequently in SPOs. Key words: Spondylitis, ankylosing; Kyphosis; Osteotomy