The utilization of second sacral alar-iliac screw fixation technique in the treatment of adult spinal deformity: analysis of risk factors for postoperative sagittal imbalance / 中华骨科杂志

Objective:To evaluate the clinical outcomes and complications of second sacral alar-iliac (S 2AI) technique utilized in degenerative spinal deformity patients, and to analyze the potential risk factors for postoperative sagittal imbalance. Methods:From January 2014 to October 2020, a consecutive cohort of 39 degenerative spinal deformity patients who were treated with S 2AI were retrospectively reviewed, including 4 males and 35 females, aged 63.1±6.7 years (range, 43-73 years). All of the patients had a minimum of 2-year follow-up. According to the sagittal vertical axis (SVA) at the final follow-up, patients were divided into 2 groups. Sagittal balance group (SVA≤50 mm) and sagittal imbalance group (SVA>50 mm). Radiographic parameters including the Cobb's angle, coronal balance distance (CBD), thoracic kyphosis (TK), lumbar lordosis (LL), SVA, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) were measured in the standing radiographs before and after operation and at the latest follow up. Comparison was made between the two groups and the differences with statistical significance were analyzed with binary logistic regression analysis. Intraoperative and postoperative complications were recorded. The Scoliosis Research Society-22 (SRS-22) score were employed to evaluate the quality of life. Results:The average follow-up period was 30.3±9.1 months (range, 43-73 months). Eighteen patients (46%) were identified with sagittal imbalance at the last follow-up. Compared with the patients in the sagittal balance group, the preoperative SVA was significantly larger (83.1±56.2 mm vs. 48.1±51.1 mm, t=2.04, P=0.049) and the postoperative TK was significantly greater (27.8°±9.6° vs. 18.9°±13.4°, t=2.36, P=0.024) for patients in the sagittal imbalance group. Scores of pain domain (3.2±0.5 vs. 3.7±0.6) and self-image domain (3.4±0.8 vs. 3.8±0.6) in sagittal imbalance group were significantly lower than those of sagittal balance group ( P<0.05). Logistic regression analysis showed that larger preoperative SVA ( OR=1.02, P=0.028) and greater postoperative TK ( OR=1.09, P=0.022) were independent risk factors for the occurrence of sagittal imbalance during the follow-up periods. Conclusion:S 2AI screw fixation can achieve satisfying coronal deformity correction and great sagittal reconstruction after surgery in patients with degenerative spinal deformity. However, sagittal imbalance may still occur during the follow-up periods. Larger preoperative SVA and greater postoperative TK are independent risk factors for the occurrence of sagittal imbalance.

The Effects of Sagittal Spino-Pelvic Alignment on the Clinical Symptoms of Thoracolumbar Kyphosis in Osteoporotic Patients

STUDY DESIGN: Retrospective study. OBJECTIVES: The purpose of this study was to assess the effect of sagittal spino-pelvic alignment on the clinical symptoms of thoracolumbar kyphosis (TLK; T10-L2 Cobb's angle >20°) in osteoporotic patients. SUMMARY OF LITERATURE REVIEW: Few studies have investigated the clinical symptoms and radiological features of TLK caused by degenerative changes. There is also controversy over whether clinical symptoms will deteriorate in patients with TLK or which treatment should be chosen according to the degree of TLK. MATERIALS AND METHODS: From May 2005 to May 2016, we reviewed 75 patients who were diagnosed with TLK (T10-L2 Cobb's angle >20°) and osteoporosis. Patients were excluded from the study if they had neurological symptoms, underlying spinal disorders, or unstable vertebral fractures. Fifty patients with TLK due to an osteoporotic vertebral compression fracture (group F) and 25 patients with senile TLK (group S) were assessed by clinical symptoms and radiological parameters. Thoracolumbar kyphosis angle and sagittal vertical axis (SVA) were also analyzed. Clinical symptoms were assessed using a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). RESULTS: There were no significant differences in clinical symptoms (VAS, ODI) and radiological parameters between groups F and S, or according to the degree of TLK(20°–30°, 30°–40°, >40°). Clinical symptoms were significantly more severe in patients with sagittal imbalance (SVA >5 cm) than in those with sagittal balance. CONCLUSIONS: Sagittal imbalance is a more important factor affecting clinical symptoms than the cause or the degree of TLK. Therefore, sagittal imbalance should be considered in the management of TLK in osteoporotic patients.

Treatment of Adult Spinal Deformity with Sagittal Imbalance Using Oblique Lumbar Interbody Fusion: Can We Predict How Much Lordosis Correction Is Possible?

STUDY DESIGN: Prospective, single-center study.PURPOSE: The current trend of operative treatment for adult spinal deformity (ASD) is combined anterior-posterior staged surgery. When anterior surgery was first performed, oblique lumbar interbody fusion (OLIF) was employed; this method became increasing popular. This study aimed to determine the lordosis correction that can be achieved using OLIF and assess whether we can preoperatively predict the lordosis correction angle achieved using OLIF.OVERVIEW OF LITERATURE: Many previous studies on OLIF have shown improved clinical and radiologic outcomes. With the increase in the popularity of OLIF, several surgeons have started using larger cages to attain greater lordosis correction. Moreover, some studies have reported complications of OLIF because of immoderate cage insertion. To our knowledge, this is the first prospective study that attempted to determine whether it is possible to predict the lordosis correction angle achieved with OLIF preoperatively, using fullextension lateral view (FELV).METHODS: Forty-six patients with ASD were enrolled. All the operations were performed by a single surgeon in two stages (first, anterior and second, posterior) with a 1-week interval. Radiological evaluation was performed by comparing the Cobb’s angle of the segmental and regional lordosis obtained using preoperative and postoperative simple radiography (including the FELV) and magnetic resonance imaging (MRI).RESULTS: Regional lordosis (L1–S1) in the whole-spine standing lateral radiograph was −3.03°; however, in the supine lateral MRI, it was 20.92°. The regional lordosis of whole-spine standing lateral and supine lateral (MRI) was significantly different. In the FELV, regional lordosis was 25.72° and that in the postoperative supine lateral (MRI) was 25.02°; these values were not significantly different.CONCLUSIONS: Although OLIF offers many advantages, it alone plays a limited role in ASD treatment. Lordosis correction using OLIF as well as lordosis determined in the FELV was possible. Hence, our results suggest that FELV can help predict the lordosis correction angle preoperatively and thus aid the selection of the appropriate technique in the second staged operation.

Pelvic Incidence Can Be Changed not only by Age and Sex, but also by Posture Used during Imaging

OBJECTIVE: Computed tomography (CT), rather than conventional 2-dimensional radiography, was used to scan and measure pelvic parameters. The results were compared with measurements using X-ray. METHODS: Pelvic parameters were measured using both CT and X-ray in 254 patients who underwent both abdomino-pelvic CT and X-ray at the pelvic site. We assessed the similarity of the pelvic parameters between the 2 exams, as well as the correlations of pelvic parameters with sex and age. RESULTS: The mean values of the subjects’ pelvic parameters measured on X-ray were: sacral slope (SS), 31.6°; pelvic tilt (PT), 18.6°; and pelvic incidence (PI), 50.2°. The mean values measured on CT were: SS, 35.1°; PT, 11.9°; and PI, 47.0°. PT was found to be 4.07° higher on X-ray and 2.98° higher on CT in women, with these differences being statistically significant (p < 0.001, p < 0.001). PI was 4.10° higher on X-ray and 2.78° higher on CT in women, with these differences also being statistically significant (p < 0.001, p=0.009). We also observed a correlation between age and PI. For men, this correlation coefficient was 0.199 measured using X-ray and 0.184 measured using CT. For women, this correlation coefficient was 0.423 measured using X-ray and 0.372 measured using CT. CONCLUSION: When measured using CT compared to X-ray, SS increased by 3.5°, PT decreased by 6.7°, and PI decreased by 3.2°. There were also statistically significant differences in PT and PI between male and female subjects, while PI was found to increase with age.

Radiologic Findings of Pelvic Parameters Related to Sagittal Balance

STUDY DESIGN: A literature review on the radiologic findings of pelvic parameters for treatment of spinal deformity OBJECTIVES: This review examines sagittal spine alignment, pelvic parameters, and methods for assessing alignment, and examines the relationships among all of these parameters to understand spinal deformity. SUMMARY OF LITERATURE REVIEW: Understanding the main pelvic and sagittal spinal parameters and recognizing their correlation is imperative in the diagnosis and treatment of various spinal disorders. MATERIALS AND METHODS: Review of the literature. RESULTS: As spinal and pelvic parameters tend to have a strong correlation, it is essential to measure not only spinal parameters but also pelvic parameters in analyzing sagittal balance. Degenerative changes have the potential to greatly disrupt the normal curvature of the spine, leading to sagittal malalignment. Analysis of sagittal balance is crucial to optimizing the management of spinal diseases. Improvement in surgical outcomes may be achieved through better understanding of radiographic spino-pelvic parameters and their association with deformity. CONCLUSIONS: Understanding spinal and pelvic parameters raises awareness of the relationship among alignment and balance, the soft tissue envelope, and compensatory mechanisms, which will, in turn, provide a more comprehensive understanding of the nature of spinal deformity and the modalities with which it is treated.

Basic Pelvic Parameters Associated with Lumbar Degenerative Disease: Review Article

STUDY DESIGN: Literature review. OBJECTIVES: The aim of this study was to present updated information on the basic pelvic parameters associated with lumbar degenerative disease. SUMMARY OF LITERATURE REVIEW: Sagittal imbalance has been known to be related to a poor prognosis in almost all adult spine problems, including lumbar degenerative disease. MATERIALS AND METHODS: Review of the relevant literature. RESULTS: Pelvic incidence is a morphologic parameter of the pelvis. It influences lumbar lordosis and thoracic kyphosis, and determines the limitations of pelvic retroversion in sagittal imbalance. Pelvic tilt is a positional parameter of the pelvis, indicating the degree of compensation for sagittal imbalance. A C7-sagittal vertical axis >5 cm, pelvic tilt >20°, and pelvic incidence-lumbar lordosis mismatch are known to be independent factors predictive of poor outcomes. CONCLUSIONS: The C7-sagittal vertical axis, pelvic tilt, and pelvic incidence-lumbar lordosis mismatch should be considered when surgery is planned for a patient with degenerative lumbar disease.

General Osteopathic Treatment is Associated with Postural Changes.

Aim: To investigate whether standard general osteopathic treatment can influence the static configuration of the vertebral column or pelvis. Material and Methods: One hundred thirteen persons, 72 females and 41 males, either symptomfree volunteers or patients with mild idiopathic back pain, were investigated using the DIERS formetric® system, before and immediately after a single session of general osteopathic treatment. Variables of static assessment of the thoraco-lumbar vertebral column and of the pelvis were compared before and after treatment, using paired statistics. Results: There was no difference between observations in the healthy controls and the symptomatic patients. The sagittal imbalance decreased significantly (two sided student’s t-test: P=0.034), apical deviation diminished (one sided student’s t-test: P= 0.047) after treatment and lordotic apex position increased (one sided student’s t-test: P=0.028). Since such changes have not been observed in a previous trial of repeat measurements without treatment, the observations in the present study suggest an effect of treatment. This effect was, however, limited to persons with sagittal imbalance not exceeding the 62nd percentile. Conclusion: General osteopathic treatment is associated with reduced sagittal imbalance and apical deviation and increased lordotic apex position, but this effect is demonstrable only in persons whose sagittal imbalance ranks in the lower or median tertile.

Retrolisthesis as a Compensatory Mechanism in Degenerative Lumbar Spine

OBJECTIVE: Posterior vertebral translation as a type of spondylolisthesis, retrolisthesis is observed commonly in patients with degenerative spinal problems. Nevertheless, there is insufficient literature on retrolisthesis compared to anterolisthesis. The purpose of this study is to clarify the clinical features of retrolisthesis, and its developmental mechanism associated with a compensatory role in sagittal imbalance of the lumbar spine. METHODS: From 2003 to 2012, 230 Korean patients who underwent spinal surgery in our department under the impression of degenerative lumbar spinal disease were enrolled. All participants were divided into four groups : 35 patients with retrolisthesis (group R), 32 patients with simultaneous retrolisthesis and anterolisthesis (group R+A), 76 patients with anterolisthesis (group A), and 87 patients with non-translation (group N). The clinical features and the sagittal parameters related to retrolisthesis were retrospectively analyzed based on the patients' medical records. RESULTS: There were different clinical features and developmental mechanisms between retrolisthesis and anterolisthesis. The location of retrolisthesis was affected by the presence of simultaneous anterolisthesis, even though it predominantly manifest in L3. The relative lower pelvic incidence, pelvic tilt, and lumbar lordosis compared to anterolisthesis were related to the generation of retrolisthesis, with the opposite observations of patients with anterolisthesis. CONCLUSION: Retrolisthesis acts as a compensatory mechanism for moving the gravity axis posteriorly for sagittal imbalance in the lumbar spine under low pelvic incidence and insufficient intra-spinal compensation.

Changes of Spinopelvic Parameter using Iliac Screw In Surgical Correction of Sagittal Imbalance Patients

STUDY DESIGN: A retrospective-based study. OBJECTIVES: To evaluate the usefulness of iliac screws in the surgical correction of sagittal imbalance by changes of spinopelvic parameters. SUMMARY OF LITERATURE REVIEW: Although reports exist regarding the fusion rates on lumbosacral fusion by iliac screws, no previous studies address the issue of changes of spinopelvic parameters on surgical correction of sagittal imbalance by iliac screws. MATERIALS AND METHODS: We analyzed a total of 23 patients who were operated on by pedicle subtraction osteotomy and posterior fusion on sagittal imbalance. Patients were divided into two groups: 1) non-iliac screw fixation and; 2) iliac screw fixation. The two groups were compared during the preoperative and postoperative stages, and the last follow-up spinopelvic parameters of two groups. RESULTS: Spinopelvic parameters, except for pelvic incidence, were corrected after surgery; some corrected values of spinopelvic parameters were lost during follow-up. There was a statistically significant difference in the last follow-up period between lumbar lordosis and pelvic tilt. Values of postoperative lumbar lordosis and pelvic tilt was similar to each other; however, during the follow-up period corrected values of spinopelvic parameters of non-iliac screw fixation group were more lost. There were no statistically significant changes in postoperative and last follow-up sacral slope and pelvic incidence. CONCLUSIONS: Sagittal imbalance could be corrected by pedicle subtraction osteotomy, and corrected values of lumbar lordosis and pelvic tilt of iliac screw fixation group could be maintained well compared to non-iliac screw fixation. Iliac screw fixation could be useful for maintenance of corrected values of spinopelvic parameters in surgical correction of sagittal imbalance.

Proximal Junctional Problems in Surgical Treatment of Lumbar Degenerative Sagittal Imbalance Patients and Relevant Risk Factors

STUDY DESIGN: Retrospective study. OBJECTIVES: As we analyze the incidence and the risk factor for proximal junctional problem after surgical treatment of lumbar degenerative sagittal imbalance, we want to contribute to reducing the junctional problem of surgical treatment of lumbar degenerative sagittal imbalance. SUMMARY OF LITERATURE REVIEW: Surgical treatment of degenerative spinal deformity has increased. Rigid fixation was a risk factor for degenerative change of adjacent segment and failure, and it remains a big challenge for the junctional problem of surgical treatment. However, research on the correlation with risk factors is rare. MATERIALS AND METHODS: Forty four patients (mean age 66.5; range, 50-74) who had surgery due to lumbar degenerative sagittal imbalance were evaluated by the risk factor associated with junctional problems from January, 2005 to December, 2011. The risk factors were analyzed by surgical factor (proximal fusion level, using iliac screw, correction or undercorrection of lumbar lordosis compared with pelvic incidence) and patient factor (age, bone marrow density, body mass index). RESULTS: Junctional problems occurred in 18 patients (41%) out of 44 patients. Among these problems, there were 10 cases of fractures, 8 cases of junctional kyphosis, and 4 cases of proximal screw pull out. . Among the risk factors, only the correction or undercorrection of lumbar lordosis compared with pelvic incidence in surgical factor was statistically significant. Other surgical factors and patient factors were not statistically significant. CONCLUSIONS: Junctional problems after a surgical treatment of lumbar degenerative sagittal imbalance were common. However, we could not know the exact risk factor of junctional problems except the degree of correction of lumbar lordosis compared with pelvic incidence, because most of the risk factors were not statistically significant. So, further evaluations of the risk factor of lumbar degenerative sagittal imbalance are required.

The Impact on Clinical Results by Sagittal Imbalance in Posterior Fixation for Thoraco-lumbar Burst Fractures

PURPOSE: Evaluate the effects of sagittal imbalance on the clinical outcomes in thoracolumbar burst fractures. MATERIALS AND METHODS: We evaluated 11 patients who had received posterior fixation for unstable burst fractures. Radiologic assessment including the compression ratio, focal kyphotic angle and sagittal balance were obtained. The clinical outcomes were assessed by ODI, VAS and SF-36. We subdivided the patients into sagittal balance and imbalance group, and compared with clinical outcomes. The relationship between radiologic and clinical outcomes was examined using correlation analysis. RESULTS: The radiologic assessment were changed on preoperative and postoperative as follows: mean compression ratio: 15.2%, 4.9%, mean focal kyphotic angle: 43.2degrees, 20.9degrees. The mean sagittal balance was 11.5 cm. The mean score of VAS, ODI, Physical and Mental Component Summary of SF-36 were 3.7, 45.8, 43.3 and 39.8, respectively. The ODI was significantly higher in sagittal imbalance group, and SF-36 was significantly higher in sagittal balance group (p<0.05). The VAS was correlated with compression ratio and focal kyphotic angle. The ODI and Mental Component Summary of SF-36 were correlated with sagittal imbalance. CONCLUSION: Sagittal balance effects on the functions of spine, surgical treatment should be carefully considered with unstable burst fractures.

Optimal Standing Radiographic Positioning in Patients with Sagittal Imbalance

STUDY DESIGN: This is a review of the literature about radiographic positioning for patients with sagittal imbalance. OBJECTIVES: We wanted to verify the optimal radiographic positioning for patients with sagittal imbalance. SUMMARY OF LITERATURE REVIEW: The standing lateral whole spine radiograph for identifying the sagittal alignment has a different value for the SVA according to the radiographic positioning. MATERIALS AND METHODS: This is a review of the literature. RESULTS: The fists-on-the clavicle position or the cross-arm position not only represents a functional standing position, but it also causes a less negative shift of the SVA in patients with sagittal imbalance. Both the extended hip and knee positions are necessary to exclude a compensation mechanism of the lower extremity. CONCLUSIONS: The optimal radiographic positioning is essential to examine the degrees of sagittal imbalance.

Clinical Outcomes and Complications after Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance Patients : A Long-Term Follow-Up Data

OBJECTIVE: Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes. METHODS: We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation. RESULTS: Following surgery, lumbar lordosis increased from -14.1degrees +/- 20.5degrees to -46.3degrees +/- 12.8degrees (p < 0.0001), and the C7 plumb line improved from 115 +/- 43 mm to 32 +/- 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 late-onset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results. CONCLUSION: Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results.

Sagittal Imbalance

Sagittal imbalance in adult population has a significant impact on health-related quality of life. Successful surgical treatment of sagittal plane deformities is crucial because it can significantly improve patient's quality of life. However, this reconstructive surgery for deformity is challenging for both patient and physician. Osteoporosis and systemic disease are important considerations in preparation of the surgery because they may be associated with the relatively high rate of complications. Therefore, careful planning of the meticulous surgical technique and vigilant postoperative follow-up may help in minimizing the occurrence of complications and optimizing the patients' out- comes.

Loss of Sagittal Balance and Clinical Outcomes following Corrective Osteotomy for Lumbar Degenerative Kyphosis / 대한정형외과학회잡지

PURPOSE: To report the loss of correction of a sagittal imbalance and the clinical outcomes after a corrective osteotomy for lumbar degenerative kyphosis. MATERIALS AND METHODS: This study analyzed the radiological parameters, surgical techniques, and clinical outcomes of 23 patients, who underwent corrective osteotomy for lumbar degenerative kyphosis. The patients were divided into groups I (>5 cm loss of correction of sagittal imblance, 12 patients) and II (3.5 out of 5, 11 patients) was compared with group B (low satisfaction score group <3.5 out of 5, 12 patients). RESULTS: The sagittal imbalance was corrected by performing a Smith-Petersen osteotomy (SPO) in 11 cases and Pedicle subtraction osteotomy (PSO) in 12. The mean preoperative sagittal imbalance was improved from 26.4 cm to 4.05 cm, postoperatively, and 11.2 cm at the last follow up. The mean loss of correction was 11.2 cm in group I and 2.3 cm in group II. The mean satisfaction score was 4.56 in group A and 2.18 in group B. The presence of an old compression fracture was found to be related to the loss of correction, and the preoperative symptomatic spinal stenosis was related to poor clinical outcomes. CONCLUSION: After mean 45 month follow up, the mean loss of sagittal correction was 38.3%, which mainly occurred at the proximal unfused segment. The clinical success rate was 45.5%, regardless of the loss of sagittal balance correction.

Chance Fracture Secondary to a Healed Kyphotic Compression Osteoporotic Fracture

Chance fracture is an unstable vertebral fracture, which usually results from a high velocity injury. An elderly lady with a previously healed osteoporotic fracture of the T12 and L1 vertebra which resulted in a severe kyphotic deformity subsequently sustained a Chance fracture of the adjacent L2 vertebrae after a minor fall. The previously fracture left her with a deformity which resulted in significant sagittal imbalance therefore predisposing her to this fracture. This case highlights the importance of aggressive treatment of osteoporotic fractures in order to prevent significant sagittal imbalance from resultant (i.e. kyphotic) deformity.

Sagittal Imbalance / 대한척추외과학회지

Sagittal spinal balance is an essential factor for not only the external appearance, but also for the spine's function. Fixed sagittal imbalance is the result of different causes, and this generally requires surgical treatment. Sagittal imbalance is mainly caused by decreased lumbar lordosis and increased thoracic kyphosis, and it can also be influenced by the pelvic incidence and flexion contracture of the hip and knee joints. So, a careful understanding and clinically considering the many factors and compensatory mechanisms that are associated with sagittal imbalance are needed. Proper surgical treatments provide a satisfactory outcome for these patients and good radiographic results. Correction of sagittal imbalance generally requires spinal osteotomy and long segment fusion. For the surgical treatment, we should consider the perioperative and postoperative complications of osteotomy and long segment fusion and then make proper decisions for the range of fusion of the proximal and distal sides and the selection of the correct method of osteotomy, the ideal correction angle and the best method of internal fixation. Problems such as loss of correction may occur postoperatively due to kyphotic change and pseudarthrosis of the proximal and distal sides. Therefore, we need to conduct a thorough analysis and make a detailed plan for the surgical approach. We should also study and understand the radiological factors when treating sagittal spinal balance because not only the spine, but also the pelvis, hip and knee joints are involved in forming the sagittal balance

Comparison of Smith-Petersen Osteotomy versus Pedicle Subtraction Osteotomy for the Correction of Fixed Sagittal Imbalance / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVES: The purpose of this study was to compare the results between Smith-Petersen and pedicle subtraction osteotomies for fixed sagittal imbalance, and to determine the specific indications for each. LITERATURE REVIEW SUMMARY: Smith-Petersen (SPO) and pedicle subtraction osteotomies (PSO) are the techniques most commonly used to correct fixed sagittal imbalance of the spine, but there are no reports regarding the superiority of either technique. A Smith-Petersen osteotomy is an anterior opening wedge osteotomy, which hinges on the posterior edge of the intervertebral disc, while a pedicle subtraction osteotomy is a posterior closing wedge osteotomy, without distracting the anterior column, with the hinge on the anterior aspect of the vertebral body. MATERIALS AND METHODS: Thirty patients (mean age 40.1 years, range 20 ~64 years), who underwent a SPO, were compared with forty-one patients (mean age 54.5 years, range 21 ~73 years) who underwent a PSO. The SPO was carried out in more than three segments (3 SPOs) in fourteen of the SPO group. The average follow-up periods were 4.6 years, ranging from 2 to 11.5 years, and 3.8 years, ranging from 2 to 7.1 years, for the SPO and PSO groups, respectively. Patients were evaluated by standing radiographs, chart review and outcome questionnaires. RESULTS: The mean correction of the kyphotic angle at the osteotomy sites for the SPOs was 10.7 per segment, and for those with 3 SPOs and the PSO group the average total corrections were 33.0+/-9.2 and 31.7+/-9.0, respectively. However, the improvement in sagittal balance was less statistically significantly with 3 SPOs (5.5+/-4.5 cm) than with a PSO (11.2+/-7.2 cm; p<0.01). Comparing 3 SPOs to one PSO, the SPO group decompensated the patients more substantially to the concavity (p<0.02). The mean estimated blood loss (adding up all anterior and posterior surgeries) for the procedures were 1398+/-738 (1392+/-664 mL in the 3 SPO group), and 2617+/-1645 mL in the SPO and PSO groups, respectively (p<0.001; p<0.01). The total operative times for the SPO versus the PSO groups were similar, with no statistical difference. There were substantial complications in both groups, with 13 in the 30 SPO and 30 in the 41 PSO patients. In the SPO group, 1 patient had a non-union at an osteotomy site; in the PSO group, 2 patients had a non-union at an osteotomy site. The mean Oswestry score improved from 42.3+/-14.2 to 21.3+/-14.8 postoperatively at the last visit for the SPO group and, it improved from 47.9+/-15.8 preoperatively to 29.7+/-18.3 at the last visit in PSO group (p=0.35). CONCLUSIONS: When comparing 3 Smith-Petersen osteotomies to one pedicle subtraction osteotomy, the corrections of kyphosis were almost identical, but the improvement in the C7 plumb was significantly better in the PSO group. There was a significantly greater likelihood of decompensating the patient to the concavity with the 3 SPOs than with a single PSO (p<0.02). The total operative time for the SPO versus the PSO groups showed no statistical difference. However, the blood loss was substantially greater in the PSO group (p<0.001).

Comparison of Smith-Petersen Osteotomy versus Pedicle Subtraction Osteotomy for the Correction of Fixed Sagittal Imbalance / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVES: The purpose of this study was to compare the results between Smith-Petersen and pedicle subtraction osteotomies for fixed sagittal imbalance, and to determine the specific indications for each. LITERATURE REVIEW SUMMARY: Smith-Petersen (SPO) and pedicle subtraction osteotomies (PSO) are the techniques most commonly used to correct fixed sagittal imbalance of the spine, but there are no reports regarding the superiority of either technique. A Smith-Petersen osteotomy is an anterior opening wedge osteotomy, which hinges on the posterior edge of the intervertebral disc, while a pedicle subtraction osteotomy is a posterior closing wedge osteotomy, without distracting the anterior column, with the hinge on the anterior aspect of the vertebral body. MATERIALS AND METHODS: Thirty patients (mean age 40.1 years, range 20 ~64 years), who underwent a SPO, were compared with forty-one patients (mean age 54.5 years, range 21 ~73 years) who underwent a PSO. The SPO was carried out in more than three segments (3 SPOs) in fourteen of the SPO group. The average follow-up periods were 4.6 years, ranging from 2 to 11.5 years, and 3.8 years, ranging from 2 to 7.1 years, for the SPO and PSO groups, respectively. Patients were evaluated by standing radiographs, chart review and outcome questionnaires. RESULTS: The mean correction of the kyphotic angle at the osteotomy sites for the SPOs was 10.7 per segment, and for those with 3 SPOs and the PSO group the average total corrections were 33.0+/-9.2 and 31.7+/-9.0, respectively. However, the improvement in sagittal balance was less statistically significantly with 3 SPOs (5.5+/-4.5 cm) than with a PSO (11.2+/-7.2 cm; p<0.01). Comparing 3 SPOs to one PSO, the SPO group decompensated the patients more substantially to the concavity (p<0.02). The mean estimated blood loss (adding up all anterior and posterior surgeries) for the procedures were 1398+/-738 (1392+/-664 mL in the 3 SPO group), and 2617+/-1645 mL in the SPO and PSO groups, respectively (p<0.001; p<0.01). The total operative times for the SPO versus the PSO groups were similar, with no statistical difference. There were substantial complications in both groups, with 13 in the 30 SPO and 30 in the 41 PSO patients. In the SPO group, 1 patient had a non-union at an osteotomy site; in the PSO group, 2 patients had a non-union at an osteotomy site. The mean Oswestry score improved from 42.3+/-14.2 to 21.3+/-14.8 postoperatively at the last visit for the SPO group and, it improved from 47.9+/-15.8 preoperatively to 29.7+/-18.3 at the last visit in PSO group (p=0.35). CONCLUSIONS: When comparing 3 Smith-Petersen osteotomies to one pedicle subtraction osteotomy, the corrections of kyphosis were almost identical, but the improvement in the C7 plumb was significantly better in the PSO group. There was a significantly greater likelihood of decompensating the patient to the concavity with the 3 SPOs than with a single PSO (p<0.02). The total operative time for the SPO versus the PSO groups showed no statistical difference. However, the blood loss was substantially greater in the PSO group (p<0.001).

A Clinical Analysis of Surgical Treatment of Lumbar Degenerative Kyphosis / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVES: To analyse associated preoperative conditions and postoperative causes of sagittal imbalance and to analyze clinical results of surgical treatment of lumbar degenerative kyphosis. SUMMARY OF LITERATURE REVIEW: There have been many controversies and high possibility of unsatisfactory results in surgical treatment of symptomatic degenerative lumbar kyphosis, which was complicated condition usually needed multi-level operation in old age. MATERIALS AND METHODS: We analyzed 24 patients who complained of long standing stooping as one of main symptoms with radiologically measured lumbar kyphosis and underwent surgical restoration of lumbar lordodsis with long segmental spinal fusion from 1995 to 1999. Mean follow-up was 31.9months(from 24 to 48 months). Operative treatments were posterolateral fusion with pedicular screw(15 cases), anterior and posterior interbody fusion(5 cases), posterior interbody fusion with cage(1 case) and decancellation osteotomy(3 cases). Cases divided into 2 groups(Group A: improved stooping, Group B: recurred stooping) were evaluated by radiological measurement of changes in surgically restored lumbar lordosis correlated with clinical improvement of stooping. Overall clinical results were evaluated according to Kirkaldy-Willis criteria. RESULTS: The associated conditions of preoperative lumbar kyphosis were recognized as multiple disc degeneration, segmental instability, degenerative vertebral wedging and pseudospondylolisthesis. Post-operative stooping recurred in 5 cases and caused by adjacent kyphosis in 2 cases, loss of correction in 1 case and both in 2 cases. Loss of correction was associated with pseudarthrosis in 1 case, screw loosening in 3 cases and allograft collapse in 2 cases. According to Kirkaldy-Willis, 8 cases of unsatisfactory clinical results consisted of 3 cases of pseudarthrosis out of 19 cases of Gruop A and all cases(5 cases) in group B. Most of correction loss occurred at lower lumbar spine(L3-S1) and was closely related to post-operative sagittal imbalance. CONCLUSIONS: Maintenance of well corrected lumbar lordosis for sagittal balance and prevention of pseudarthrosis were mandatory for good clinical outcome in surgical treatment of lumbar degenerative kyphosis.