Asymmetrical pedicle subtraction osteotomy for rigid degenerative lumbar kyphoscoliosis

Postoperative decrease in Hounsfield unit values at adjacent vertebrae after thoraco-pelvic fusion as a risk factor of proximal junctional kyphosis

Proximal junctional kyphosis and failure is a common complication of adult spinal deformity surgery, with osteoporosis as a risk factor. This retrospective study investigated the influence of long thoracolumbar fusion with pelvic fixation on regional bone density of adjacent vertebrae (Hounsfield units on computed tomography) and evaluated the association between bone loss and the incidence of proximal junctional kyphosis and failure. Patients who underwent long thoracolumbar fusion (pelvis to T10 or above) or single-level posterior lumbar interbody fusion (control group) between 2016 and 2022 were recruited. Routine computed tomography preoperatively and within 1-2 weeks postoperatively was performed. Postoperative changes in Hounsfield unit values in the vertebrae at one and two levels above the uppermost instrumented vertebrae (UIV + 1 and UIV + 2) were evaluated. Overall, 127 patients were recruited: 45 long fusion (age, 73.9 ± 5.6 years) and 82 proximal junctional kyphosis and failure (age, 72.5 ± 9.3 years). Postoperative computed tomography was performed at a median [interquartile range] of 3.0 [1.0-7.0] and 4.0 [1.0-7.0] days, respectively. In both groups, Hounsfield unit values at UIV + 2 were significantly decreased postoperatively. In the long-fusion group, Hounsfield unit values at UIV + 1 and UIV + 2 were significantly lower in patients with proximal junctional kyphosis and failure (within 18 months postoperatively) than in those without proximal junctional kyphosis and failure. Proximal junctional kyphosis and failure and long thoraco-pelvic fusion negatively affect regional Hounsfield unit values at adjacent levels immediately after surgery. Patients with subsequent proximal junctional kyphosis and failure show greater postoperative bone loss at adjacent levels than those without.

Operative strategies for ankylosing spondylitis-related thoracolumbar kyphosis: focus on the cervical stiffness, coronal imbalance and hip involvement

BACKGROUND

Cervical stiffness, coronal imbalance and limited hip movement all play crucial roles in designing the corrective surgery for ankylosing spondylitis-related thoracolumbar kyphosis (AS-TLK). However, a comprehensive classification and tailored strategies for directing clinical work are lacking. This study aims to investigate the types and surgical strategies for AS-TLK that consider cervical stiffness, coronal imbalance and hip involvement as the key factors.

METHODS

25 consecutive AS-TLK patients were divided into three types according to their accompanying features: Type I: with a flexible cervical spine; Type IIA: with a stiff cervical spine; Type IIB: with coronal imbalance; Type IIC: with limited hip movement. Type III is the mixed type with at least two conditions of Type II. Individual strategies were given correspondingly. Spinal-pelvic-femoral parameters were measured, Scoliosis Research Society outcome instrument-22 (SRS-22) was used and complications were recorded and analysed.

RESULTS

All patients (Type I 10, Type II 8 and Type III 7) underwent surgery successfully. 13 cases with 16 complications were recorded and cured. The patients were followed up for 24-65 months with an average of 33.0 ± 9.6 months. Both the sagittal and coronal parameters were corrected and decreased significantly (all, p < 0.05). SRS-22 scores showed a satisfactory outcome.

CONCLUSION

Thoracolumbar kyphosis secondary to ankylosing spondylitis are complex and variable. Considering the factors of cervical stiffness, coronal imbalance and hip involvement assists in making decisions individually and achieving a desired surgical result.

Comparison of staged LLIF combined with posterior instrumented fusion with posterior instrumented fusion alone for the treatment of adult degenerative lumbar scoliosis with sagittal imbalance

BACKGROUND

To retrospectively compare the clinical and radiological outcomes of staged lateral lumbar interbody fusion (LLIF) combined with posterior instrumented fusion(PIF)with PIF alone for the treatment of adult degenerative lumbar scoliosis (ADLS) with sagittal imbalance.

METHODS

ADLS patients with sagittal imbalance underwent corrective surgery were included and divided into staged group (underwent multilevel LLIF in the first-stage and PIF in the second-stage) and control group (PIF alone). The clinical and radiological outcomes were evaluated and compared between the two groups.

RESULTS

Forty-five patients with an average age of 69.7±6.3 years were enrolled, including 25 in the staged group and 20 in the control group. Compared with preoperative values, patients in both groups achieved significant improvement in terms of ODI, VAS back, VAS leg and spinopelvic parameters after surgery, which were maintained well during the follow-up period. Compared with control group, total operative time in the staged group was longer, but the amounts of blood loss and blood transfusion were reduced. The average posterior fixation segments were 6.20±1.78 in the staged group and 8.25±1.16 in the control group (P<0.01), respectively. Posterior column osteotomy (PCO) was performed in 9 patients (36%) in the staged group, while PCO and/or pedicle subtraction osteotomy were performed in 15 patients (75%) in the control group (P<0.01). There was no difference in complications between the two groups.

CONCLUSION

Both surgical strategies were effective for the treatment of ADLS with sagittal imbalance. However, staged treatment was less invasive, which reduced the number of posterior fixation segments and osteotomy requirement.

Trans-intervertebral osteotomy classification of posterior spinal corrective osteotomy procedures via the intervertebral space

•This is a diagnostic study for a classification for posterior spinal osteotomy procedures via the intervertebral space.•Proposed ​a novel classification ​with ​excellent reliability ​and ​validity, differ from the SRS-Schwab osteotomy classification.•Give a novel definition of "trans-intervertebral osteotomy" (TIO) for posterior spinal osteotomy procedures.•Thoroughly discussed about the histories of posterior spinal osteotomy procedures via the intervertebral space.•Systematically introduced the TIO technique with fine original schematics.

A 3D-printed Personalized, Combined, Modular Pedicle Subtraction Osteotomy Guide Plate System: An Experimental Study

STUDY DESIGN

Experimental study.

OBJECTIVES

The goal of this study was to develop a threedimensional (3D)-printed pedicle subtraction osteotomy (PSO) guide plate system. A 3D model and postoperative computed tomography (CT) data were used to evaluate the accuracy of osteotomy with this system.

SUMMARY OF BACKGROUND DATA

The key to the success of spinal orthopedic treatment is an effectively performed osteotomy. A 3D-printed osteotomy plate can be used for preoperative surgical planning. Due to the anatomical complexity of the spinal region, the clinical application of 3D-printed osteotomy plates remains challenging.

METHODS

The CT scans of 10 patients with thoracolumbar spinal deformities were obtained in the digital imaging and communication in medicine (DICOM) format. The diseased vertebrae and adjacent vertebrae were reconstructed and reduced by computer- aided design software, and an osteotomy plate was designed for the diseased vertebrae. The 3D-printed spinal model and osteotomy plate were used to simulate the operation for PSO. After the operation, the vertebral body treated by osteotomy underwent a CT scan, and the findings were compared with the preoperative design to evaluate the osteotomy accuracy.

RESULTS

The new 3D guide plate and spine model were used to successfully simulate 10 cases of PSO, and the comparison of the preoperative and postoperative states indicated that the osteotomy outcomes were excellent.

CONCLUSIONS

The new 3D-printed PSO guide plate system can be used for preoperative osteotomy planning and demonstrates good accuracy. The results can be used to develop 3D-printed plans for PSO in clinical practice.

Adult spinal deformity surgery: posterior three-column osteotomies vs anterior lordotic cages with posterior fusion. Complications, clinical and radiological results. A systematic review of the literature

PURPOSE

The aim of our study is to analyse mid- to long-term severe adult spinal deformity (ASD) surgery outcomes by comparing three-column osteotomies (3CO) and multiple anterior interbody fusion cages (AC).

MATERIALS AND METHODS

The PRISMA flowchart was used to systematically review the literature. Only articles with a minimum 24-month follow-up were examined, and 11 articles were included. The following radiological parameters were observed: pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), sagittal vertical axis (SVA), Cobb angle and T1-sacrum plumbline. Clinical outcome was assessed using the visual analogue scale (VAS) and Oswestry disability index (ODI) scores. The main complications were analysed, and the two groups were compared.

RESULTS

Except for age, the two populations were homogeneous. Both techniques had the same number of posterior instrumented levels (7.4 ± 1.7). The AC group had a mean 3 ± 1.4 interbody fusions per patient. In the PSO group, all patients had 1 3CO and 89.8% of the osteotomies were performed at L2 or L3 vertebrae. No difference was observed between the two groups in terms of clinical outcomes. Both techniques were effective in sagittal parameters restoration with a final PI-LL mismatch = 4.4°. The PSO group had a statistically higher rate of intraoperative blood loss (p = 0.036), major complications, pseudoarthrosis and dural tears (p < 0.001).

CONCLUSION

Both PSO and multiple AC are effective in treating ASD. Multiple AC seems more suitable when treating older patients because of a lower intraoperative blood loss, lower rate of major complications and fewer number of revision surgeries.

Analysis of Radiographic Spinopelvic Parameters in Patients With Degenerative Lumbar Kyphoscoliosis

Purpose:

To analyze the relationships between coronal and sagittal spinopelvic parameters in degenerative lumbar kyphoscoliosis (DLKS).

Methods:

We enrolled 75 patients with DLKS for a radiographic study between January 2016 and September 2018. Correlations between coronal and sagittal spinopelvic radiographic parameters were analyzed. Then patients were divided into 2 groups: sagittal balanced group (SVA< = 5 cm, 30 patients) and sagittal imbalanced group (SVA >5 cm, 45 patients), and relevant parameters were compared.

Results:

The Cobb angle and lumbar lordosis of the DLKS patients were 24.87 ± 11.59° and 17.26 ± 12.24°, respectively. The average age was 68 years old (range: 42-82), and the sex ratio was 2.6:1 (female: 54 patients; male: 21 patients). 50 patients (66.7%) located convexity of the curve at left side, while 25 patients (33.3%) at right side. The Cobb angle correlated with LL-TK (r = −0.228, p = 0.049), LL (r = −0.255, p = 0.027) and SS (r = −0.232, p = 0.045). There were significant differences in PI-LL (t = −3.484, P = 0.001), LL-TK (t = 2.354, P = 0.023), PI (t = −3201, P = 0.002) and PT (t = −2.521, P = 0.014) between sagittal balanced and imbalanced group.

Conclusions:

In degenerative lumbar kyphoscoliosis, there are some correlations between coronal and sagittal spinopelvic parameters. Moreover, PI-LL, LL-TK, PI, PT were significantly different between sagittal balanced and imbalanced DLKS patients.

Asymmetrical pedicle subtraction osteotomy for correction of concurrent sagittal-coronal imbalance in adult spinal deformity: a comparative analysis

OBJECTIVE

Rigid multiplanar thoracolumbar adult spinal deformity (ASD) cases are challenging and many require a 3-column osteotomy (3CO), specifically asymmetrical pedicle subtraction osteotomy (APSO). The outcomes and additional risks of performing APSO for the correction of concurrent sagittal-coronal deformity have yet to be adequately studied.

METHODS

The authors performed a retrospective review of all ASD patients who underwent 3CO during the period from 2006 to 2019. All cases involved either isolated sagittal deformity (patients underwent standard PSO) or concurrent sagittal-coronal deformity (coronal vertical axis [CVA] ≥ 4.0 cm; patients underwent APSO). Perioperative and 2-year follow-up outcomes were compared between patients with isolated sagittal imbalance who underwent PSO and those with concurrent sagittal-coronal imbalance who underwent APSO.

RESULTS

A total of 390 patients were included: 338 who underwent PSO and 52 who underwent APSO. The mean patient age was 64.6 years, and 65.1% of patients were female. APSO patients required significantly more fusions with upper instrumented vertebrae (UIV) in the upper thoracic spine (63.5% vs 43.3%, p = 0.007). Radiographically, APSO patients had greater deformity with more severe preoperative sagittal and coronal imbalance: sagittal vertical axis (SVA) 13.0 versus 10.7 cm (p = 0.042) and CVA 6.1 versus 1.2 cm (p < 0.001). In APSO cases, significant correction and normalization were achieved (SVA 13.0-3.1 cm, CVA 6.1-2.0 cm, lumbar lordosis [LL] 26.3°-49.4°, pelvic tilt [PT] 38.0°-20.4°, and scoliosis 25.0°-10.4°, p < 0.001). The overall perioperative complication rate was 34.9%. There were no significant differences between PSO and APSO patients in rates of complications (overall 33.7% vs 42.3%, p = 0.227; neurological 5.9% vs 3.9%, p = 0.547; medical 20.7% vs 25.0%, p = 0.482; and surgical 6.5% vs 11.5%, p = 0.191, respectively). However, the APSO group required significantly longer stays in the ICU (3.1 vs 2.3 days, p = 0.047) and hospital (10.8 vs 8.3 days, p = 0.002). At the 2-year follow-up, there were no significant differences in mechanical complications, including proximal junctional kyphosis (p = 0.352), pseudarthrosis (p = 0.980), rod fracture (p = 0.852), and reoperation (p = 0.600).

CONCLUSIONS

ASD patients with significant coronal imbalance often have severe concurrent sagittal deformity. APSO is a powerful and effective technique to achieve multiplanar correction without higher risk of morbidity and complications compared with PSO for sagittal imbalance. However, APSO is associated with slightly longer ICU and hospital stays.

Validation Study of Rajasekaran's Kyphosis Classification System: Do We Clearly Understand Single- and Two-Column Deficiencies?

Study Design

Multicenter validation study.

Purpose

To evaluate the inter-rater reliability of Rajasekaran’s kyphosis classification through a multicenter validation study.

Overview of Literature

The classification of kyphosis, developed by Rajasekaran, incorporates factors related to curve characteristics, including column deficiency, disc mobility, curve magnitude, and osteotomy requirements. Although the classification offers significant benefits in determining prognosis and management decisions, it has not been subjected to multicenter validation.

Methods

A total of 30 sets of images, including plain radiographs, computed tomography scans, and magnetic resonance imaging scans, were randomly selected from our hospital patient database. All patients had undergone deformity correction surgery for kyphosis. Twelve spine surgeons from the Asia-Pacific region (six different countries) independently evaluated and classified the deformity types and proposed their surgical recommendations. This information was then compared with standard deformity classification and surgical recommendations.

Results

The kappa coefficients for the classification were as follows: 0.88 for type 1A, 0.78 for type 1B, 0.50 for type 2B, 0.40 for type 3A, 0.63 for type 3B, and 0.86 for type 3C deformities. The overall kappa coefficient for the classification was 0.68. Regarding the repeatability of osteotomy recommendations, kappa values were the highest for Ponte’s (Schwab type 2) osteotomy (kappa 0.8). Kappa values for other osteotomy recommendations were 0.52 for pedicle subtraction/disc-bone osteotomy (Schwab type 3/4), 0.42 for vertebral column resection (VCR, type 5), and 0.30 for multilevel VCRs (type 6).

Conclusions

Excellent accuracy was found for types 1A, 1B, and 3C deformities (ends of spectrum). There was more variation among surgeons in differentiating between one-column (types 2A and 2B) and two-column (types 3A and 3B) deficiencies, as surgeons often failed to recognize the radiological signs of posterior column failure. This failure to identify column deficiencies can potentially alter kyphosis management. There was excellent consensus among surgeons in the recommendation of type 2 osteotomy; however, some variation was observed in their choice for other osteotomies.

Multilevel extended posterior column osteotomy plus unilateral cage strutting for degenerative lumbar kyphoscoliosis

OBJECTIVE

To explore the surgical outcome of patients with degenerative lumbar kyphoscoliosis who underwent multilevel extended posterior column osteotomy (PCO) plus unilateral cage strutting (UCS).

METHODS

From Jan 2012 to Aug 2017, 23 patients with degenerative lumbar kyphoscoliosis who underwent multilevel extended PCO plus UCS technique (study group) and 13 patients who underwent asymmetrical pedicle subtraction osteotomy (PSO) technique (control group) were retrospectively reviewed; the radiological features, including coronal/sagittal deformity, and clinical evaluation including Oswestry Disability Index (ODI), visual analog scale (VAS), and Japanese Orthopedic Association (JOA) scores-lumbar were assessed before surgery and at follow-up.

RESULTS

All patients underwent the operation successfully. There was no difference in fusion level, blood loss, and follow-up duration between the two groups; the operation time and length of hospital stay were shorter in study group than that in control group. All patients achieved significant correction of both scoliotic and kyphotic deformity and maintained the correction at minimum of two year follow-up, without any difference in deformity correction and correction loss between the two groups. All patients got back pain and leg pain alleviation and neurological function improvement at two year follow-up, without any difference between the two groups. The incidence of complications was lower in study group than that in control group.

CONCLUSION

Multilevel extended PCO plus UCS procedure could achieve significant correction of scoliosis and kyphosis in the treatment of degenerative lumbar kyphoscoliosis, presenting less surgery time, lower incidence of complication, and shorter hospital stay when compared with the asymmetric PSO technique.

Asymmetric Pedicle Subtraction Osteotomy for Adult Spinal Deformity with Coronal Imbalance: Complications, Radiographic and Surgical Outcomes

BACKGROUND

Asymmetric pedicle subtraction osteotomy (APSO) can be utilized for adult spinal deformity (ASD) with fixed coronal plane imbalance. There are few reports investigating outcomes following APSO and no series that include multiple revision cases.

OBJECTIVE

To detail our surgical technique and experience with APSO.

METHODS

All thoracolumbar ASD cases with a component of fixed, coronal plane deformity who underwent APSO from 2004 to 2016 at one institution were retrospectively reviewed. Preoperative and latest follow-up radiographic parameters and data on surgical outcomes and complications were obtained.

RESULTS

Fourteen patients underwent APSO with mean follow-up of 37-mo. Ten (71.4%) were revision cases. APSO involved a mean 12-levels (range 7-25) and were associated with 3.0 L blood loss (range 1.2-4.5) and 457-min of operative time (range 283-540). Surgical complications were observed in 64.3%, including durotomy (35.7%), pleural injury (14.3%), persistent neurologic deficit (14.3%), rod fracture (7.1%), and painful iliac bolt requiring removal (7.1%). Medical complications were observed in 14.3%, comprising urosepsis and 2 cases of pneumonia. Two 90-d readmissions (14.3%) and 5 reoperations (4 patients, 28.6%) occurred. Mean thoracolumbar curve and coronal vertical axis improved from 31.5 to 16.4 degrees and 7.8 to 2.9 cm, respectively. PI-LL mismatch, mean sagittal vertical axis, and pelvic tilt improved from 40.0 to 27.9-degrees, 10.7 to 3.5-cm, and 34.4 to 28.3-degrees, respectively.

CONCLUSION

The APSO, in both a revision and non-revision ASD population, provides excellent restoration of coronal balance-in addition to sagittal and pelvic parameters. Employment of APSO must be balanced with the associated surgical complication rate (64.3%).

Asymmetric Three-Column Osteotomy for Coronal Malalignment in Adult Patients with Prior Thoracic Fusion for Adolescent Idiopathic Scoliosis: Three-Year Follow-up

OBJECTIVE

In the setting of a previous proximal fusion, an asymmetric 3-column osteotomy (3CO) can provide tremendous deformity correction. Our goal was to evaluate outcomes and complications of asymmetric 3CO through the proximal fusion mass, for coronal malalignment in patients with previous long thoracic fusion for adolescent idiopathic scoliosis.

METHODS

This was a retrospective case series. Thirteen individuals with a history of a long thoracic fusion underwent asymmetric 3CO for persistent coronal malalignment. Clinical chart review was conducted to determine perioperative complications and radiographs evaluated for alignment.

RESULTS

Thirteen patients (age: 57.8 ± 12.2 years; 0 male, 13 female) completed a mean follow-up of 42.4 months. There was significant improvement in coronal and sagittal alignment, and pelvic incidence-lumbar lordosis postoperatively (P < 0.05). One patient developed lower-extremity weakness requiring revision decompression 72 hours postoperatively; the weakness subsequently resolved. One patient had a foot drop postoperatively. At final follow-up, 12 of 13 patients had grade 1 fusion at the osteotomy site; 1 patient had a grade 2 fusion. None of the patients developed a pseudarthrosis, or superficial or deep infections.

CONCLUSIONS

Patients with a history of previous thoracic fusion for adolescent idiopathic scoliosis and coronal malalignment may develop painful degeneration of the segments caudal to the fusion as adults. In this setting, extension of fusion to the sacropelvis alone may worsen the patient's coronal alignment. An asymmetric 3CO may be considered at the proximal fusion mass to achieve realignment objectives, with an acceptable complication rate and an expected improvement in outcomes.

Transpedicular Wedge Resection Osteotomy of the Apical Vertebrae for the Treatment of Severe and Rigid Thoracic Kyphoscoliosis: A Retrospective Study of 26 Cases

STUDY DESIGN

Retrospective analysis of clinical records.

OBJECTIVE

To determine the efficacy of transpedicular wedge resection osteotomy (TWRO) of the apical vertebrae to treat severe and rigid thoracic kyphoscoliosis in 26 adults.

SUMMARY OF BACKGROUND DATA

Although posterior vertebral column resection has traditionally been used to correct severe and rigid kyphoscoliosis, TWRO may achieve the same correction with a shorter operative time and lower rate of complications.

METHODS

Between May 2011 and December 2014, 29 adults underwent a TWRO of the apical vertebrae for severe and rigid thoracic kyphoscoliosis, and 26 adults completed the 24-month follow-up. Radiologic measurements, including coronal plane major curve, kyphotic curve, coronal offset, and sagittal offset, were measured and compared. The following patient-reported health-related quality of life outcomes, including Oswestry Disability Index score, visual analog scale score for back pain, and SRS-22 questionnaire, were used to evaluate the clinical outcomes.

RESULTS

For the 26 patients followed over 24 months, the mean coronal plane major curve improved from 107.6° to 37.5° immediately after surgery and to 40.0° at 24 months postoperatively. The mean kyphotic curve improved from 90.6° to 30.5° immediately after surgery and to 33.3° at 24 months postoperatively. The mean coronal offset and sagittal offset were also improved. Improved self-reported quality of life scores were achieved postoperatively and at 24 months postoperatively, including all domains of the SRS-22 questionnaire. Bony fusion was achieved at 6 or 12 months in all patients. Unilateral leg paresis occurred in one case and recovered after three months, with a neurologic complication rate of 3.8%.

CONCLUSIONS

TWRO of the apical vertebrae as a treatment for severe and rigid thoracic kyphoscoliosis in adult patients provided excellent clinical outcomes. However, the procedure remains technically demanding and exhausting, with a potential risk for complications.

LEVEL OF EVIDENCE

Level IV.

Radiographic outcome and complications after single-level lumbar extended pedicle subtraction osteotomy for fixed sagittal malalignment: a retrospective analysis of 55 adult spinal deformity patients with a minimum 2-year follow-up

OBJECTIVEFixed sagittal spinal malalignment is a common problem in adult spinal deformity (ASD). Various three-column osteotomy techniques, including the extended pedicle subtraction osteotomy (ePSO), may correct global and regional malalignment in this patient population. In contrast to the number of reports on traditional PSO (Schwab grade 3 osteotomy), there is limited literature on the outcomes of ePSO (Schwab grade 4 osteotomy) in ASD surgery. The objective of this retrospective study was to provide focused investigation of radiographic outcomes and complications of single-level lumbar ePSO for ASD patients with fixed sagittal malalignment.METHODSConsecutive ASD patients in whom sagittal malalignment had been treated with single-level lumbar ePSO at the authors' institution between 2010 and 2015 were analyzed, and those with a minimum 2-year follow-up were included in the study. Radiographic analyses included assessments of segmental lordosis through the ePSO site (sagittal Cobb angle measured from the superior endplate of the vertebra above and inferior endplate of the vertebra below the ePSO), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence and LL mismatch, thoracic kyphosis (TK), and sagittal vertical axis (SVA) on standing long-cassette radiographs. Complications were analyzed for the entire group.RESULTSAmong 71 potentially eligible patients, 55 (77%) had a minimum 2-year follow-up and were included in the study. Overall, the average postoperative increases in ePSO segmental lordosis and overall LL were 41° ± 14° (range 7°-69°, p < 0.001) and 38° ± 11° (range 9°-58°, p < 0.001), respectively. The average SVA improvement was 13 ± 7 cm (range of correction: -33.6 to 3.4 cm, p < 0.001). These measurements were maintained when comparing early postoperative to last follow-up values, respectively (mean follow-up 52 months, range 26-97 months): ePSO segmental lordosis, 34° vs 33°, p = 0.270; LL, 47.3° vs 46.7°, p = 0.339; and SVA, 4 vs 5 cm, p = 0.330. Rod fracture (RF) at the ePSO site occurred in 18.2% (10/55) of patients, and pseudarthrosis (PA) at the ePSO site was confirmed by CT imaging or during rod revision surgery in 14.5% (8/55) of patients. Accessory supplemental rods across the ePSO site, a more recently employed technique, significantly reduced the occurrence of RF or PA on univariate (p = 0.004) and multivariable (OR 0.062, 95% CI 0.007-0.553, p = 0.013) analyses; this effect approached statistical significance on Kaplan-Meier analysis (p = 0.053, log-rank test). Interbody cage placement at the ePSO site resulted in greater ePSO segmental lordosis correction (45° vs 35°, p = 0.007) without significant change in RF or PA (p = 0.304). Transient and persistent motor deficits occurred in 14.5% (8/55) and 1.8% (1/55) of patients, respectively.CONCLUSIONSExtended PSO is an effective technique to correct fixed sagittal malalignment for ASD. In comparison to traditional PSO techniques, ePSO may allow greater focal correction with comparable complication rates, especially with interbody cage placement at the ePSO site and the use of accessory supplemental rods.

Radiographic and Clinical Outcomes From the Use of S2 Alar Screws in Surgery for Adult Spinal Deformity

STUDY DESIGN

Retrospective.

OBJECTIVES

To evaluate the efficacy of S2 alar screws in surgery for correction of adult spinal deformity (ASD).

METHODS

We retrospectively reviewed the cases of 23 patients (mean follow-up: 18.5 months, minimum 12 months) who underwent corrective surgery for ASD using S2 alar screws as anchors for instrumentation of lower vertebrae. The background of the patients and their spinopelvic parameters (pelvic incidence [PI], pelvic tilt [PT], lumbar lordosis [LL], thoracic kyphosis [TK], sagittal vertical axis [SVA], and PI-LL) were evaluated.

RESULTS

LL was improved from 9.7 ± 20.5° and SVA from 141.0 ± 64.0 mm before surgery to 39.0 ± 9.6° and 51.7 ± 40.8 mm immediately after surgery, respectively, and 38.2 ± 12.7° and 70.5 ± 59.2 mm at final follow-up. In 13 patients without sufficient correction (postoperative PI-LL ≥10°), bone mineral density and postoperative LL were significantly less, and PI, PI-LL, and PT were significantly greater than in patients with postoperative PI-LL <10°, suggesting that these are risk factors for undercorrection. In 5 patients, SVA increased more than 40 mm during follow-up. Postoperative LL was significantly less (31.4° vs 41.0°) and postoperative PI-LL was significantly greater (21.6° vs 9.3°) in these patients, suggesting a PI-LL mismatch induces postoperative progression of global malalignment.

CONCLUSIONS

Use of S2 alar screws as anchors for instrumentation in ASD surgery should be restricted. Their use might be an option for patients with low PI, and without severe osteoporosis, in whom efficient surgical correction can be obtained.

A Classification for Kyphosis Based on Column Deficiency, Curve Magnitude, and Osteotomy Requirement

BACKGROUND

There is a lack of a classification system providing uniformity in description and guiding management decisions for kyphotic spinal deformities. We developed such a classification based on column deficiency, flexibility of disc spaces, curve magnitude, and correlation with the corrective osteotomy required.

METHODS

A classification was developed based on analysis of 180 patients with thoracolumbar kyphosis requiring osteotomy. The deformity was classified as Type I if the anterior and posterior columns were intact (IA indicated mobile disc spaces and IB, ankylosed segments). Type II indicated deficiency of only 1 column (IIA = anterior column and IIB = posterior column). Type III indicated deficiency of both columns (IIIA = kyphosis of ≤60°, IIIB = kyphosis of >60°, and IIIC = buckling collapse). A prospective analysis of 76 patients was performed to determine interobserver variability and the ability of the classification to guide selection of osteotomies of increasing complexity, including the Ponte osteotomy, pedicle subtraction osteotomy, disc bone osteotomy, single vertebrectomy, multiple vertebrectomies, and anterior in situ strut fusion procedure.

RESULTS

The mean age of the 76 patients was 21.2 years, the mean kyphosis was 69.9° (range, 26° to 120°), and the mean follow-up duration was 30 months. Six deformities were classified as IA, 5 as IB, 5 as IIA, 2 as IIB, 13 as IIIA, 35 as IIIB, and 10 as IIIC. Four surgeons classifying the deformities had a high agreement rate (kappa = 0.83), with the highest agreement for Types IA, IB, and IIIB. A correlation between the type of deformity and the osteotomy performed demonstrated that the classification could indicate the type of osteotomy required. All 18 patients with Type-I or II kyphosis were treated with Ponte, pedicle subtraction, or disc bone osteotomy. Forty-three (90%) of the 48 patients with Type IIIA or IIIB underwent vertebrectomy (single in 27 [56%] and multiple in 16 [33%]), and only 5 (10%) underwent disc bone osteotomy. Seven of the 10 patients with Type-IIIC kyphosis were treated with multiple vertebrectomies, with 5 of them needing preoperative halo gravity traction; the other 3 patients underwent an anterior in situ strut fusion procedure.

CONCLUSIONS

The proposed classification based on the morphology of column deficiency, flexibility, and curve magnitude demonstrated a high interobserver agreement and ability to guide selection of the appropriate osteotomy.

CLINICAL RELEVANCE

A novel classification system for kyphosis based on spinal column deficiency, flexibility of disc spaces, and curve magnitude would bring uniformity in management and help guide surgeons in the choice of the appropriate corrective osteotomy.

Three column osteotomy for adult spine deformity: comparison of outcomes and complications between kyphosis and kyphoscoliosis

BACKGROUND

To compare the surgical outcomes and complications between kyphosis and kyphoscoliosis when using three-column osteotomies.

METHODS

Adult spine deformity (ASD) patients with three column osteotomies from March 2005 to December 2014 in our center were retrospectively reviewed. Pre- and postoperative standing postero-anterior and lateral radiographs of the entire spine were obtained. Scoliosis Research Society-22 questionnaire [SRS-22] and Oswestry Disability Index [ODI] were administered preoperatively, postoperatively (surveys within 2 months after surgery), and at final follow-up. Patients were assigned to one of two groups according to pre-operative coronal curve magnitude: (1) if coronal curve <10°, patients were assigned to kyphosis group (K group); (2) if coronal curve >40°, patients were assigned to kyphoscoliosis group (S group).

RESULTS

33 ASD patients were assigned to the kyphosis group (K group), of which 26 received PSO (pedicle subtraction osteotomy) and 7 VCR (vertebral column resection). 76 patients were assigned to kyphoscoliosis group (S group), of which 50 received PSO and 26 VCR. Patients in the K group were significantly older than in the S group (42.8 vs. 33.7 years, p < .05). Significantly longer OT (operation time) and more EBL (estimated blood loss) were observed in the S group as compared to K group (OT: 282 vs. 205 min, p < .05; EBL: 1827 vs. 1214ml, p < .05). No significant difference was noted for number of fusion levels between the groups (12.4 vs. 12.7, p > .05). Pre-operative radiographic parameters demonstrated no difference of GK (global kyphosis) and SVA (sagittal vertical axis) between the two groups (GK: 74.7° vs 76.2°, p > .05; SVA:53.2 vs. 55.7mm, p > .05). K group had larger KF than S group (26% vs. 15%, p < .05). Overall complication rate was higher in S group than in K group (30.3% vs. 18.2%, p < .05). No difference of neurological complication rates between the two groups (9.1% vs. 10.5%, p > .05).

CONCLUSIONS

Kyphoscoliosis group had less KF, GK correction and more OT, EBL and surgical complications when receiving three column osteotomies.

Evaluation of the location of intervertebral cages during oblique lateral interbody fusion surgery to achieve sagittal correction

Introduction

Oblique lateral interbody fusion (OLIF) can achieve recovery of lumbar lordosis (LL) in minimally invasive manner. The current study aimed to evaluate the location of lateral intervertebral cages during OLIF in terms of LL correction.

Methods

The subjects were patients who underwent OLIF for lumbar degenerative diseases, including lumbar spinal stenosis, spondylolisthesis, and discogenic low back pain. Their clinical outcome was evaluated using visual analogue scale on lower back pain (LBP), leg pain and numbness. The following parameters were retrospectively evaluated on plain radiographic images and computed tomography scans before and at 1 year after OLIF: the intervertebral height, vertebral translation, and sagittal angle. The cage position was defined by equally dividing the caudal endplate into five zones (I to V), and its association with segmental lordosis restoration was analyzed. Subjects were also evaluated for a postoperative endplate injury.

Results

Eighty patients (121 fused levels) with lumbar degeneration who underwent OLIF were included. There were no significant specific distribution in preoperative disc pathology such as disc angle, height, and translation. After OLIF, sagittal alignment was improved with an average correction angle of 3.8º at the instrumented segments in a level-independent fashion. All cases showed significant improvement in clinical outcomes, and had improvement in the radiological parameters (P<0.05). A detailed analysis of the cage position showed that the most significant sagittal correction and the most postoperative endplate injuries occurred in the farthest anterior zone (I). Cages with a 12-mm height were associated with more endplate injuries compared with shorter cages (8 or 10 mm).

Conclusions

OLIF improves sagittal alignment with an average correction angle of 3.8º at the instrumented segments. We suggest that the optimal cage position for better lordosis correction and the fewest endplate injuries is zone II with a cage height of up to 10 mm.

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

STUDY DESIGN

A retrospective comparative study.

OBJECTIVE

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.

SUMMARY OF BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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).

Posterior Versus Three-Column Osteotomy for Late Correction of Residual Coronal Deformity in Patients With Previous Fusions for Idiopathic Scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To compare the early results of posterior column (PCO) and three-column (3CO) osteotomies performed in patients with previously fused idiopathic scoliosis and review their abilities to achieve coronal correction of residual deformities.

SUMMARY OF BACKGROUND DATA

Residual deformity of previously fused AIS can accelerate adjacent segment degeneration secondary to lowest instrumented vertebra (LIV) tilt and rotation. Many of these patients are not satisfied with their cosmetic appearance and would choose revising the deformity when future surgery is indicated.

METHODS

The data from 29 consecutive patients who underwent PCOs or 3COs for late revisions of idiopathic scoliosis were reviewed. Measurements included Cobb angle, focal osteotomy angle, and coronal balance. Perioperative data, complications, and patient-reported outcomes were also reviewed.

RESULTS

Fourteen patients were treated with PCOs and 15 with 3COs. Global coronal correction was equal between the two groups. In the PCO group, where patients underwent a mean of 2.4 osteotomies, 20.2° of correction was obtained compared to 19.5° in the 3CO group (p = .33), which all underwent single osteotomies. The average coronal correction was 9.2°/osteotomy for the PCO group and 14.1°/osteotomy for the 3CO group (p < .01). Estimated blood loss was 1,417.5 mL in the PCO group compared to 3,199.3 in the 3CO group (p < .01). Five patients (36%) had intraoperative complications in the PCO group compared to 12 (80%) in the 3CO group (p < .05). There were no differences in operative times, length of stay, or patient-reported outcomes between groups.

CONCLUSION

PCOs and 3COs performed in patients with previously fused spines for idiopathic scoliosis are effective in achieving residual deformity correction. In cases of posterior fusions, where the patient has a mobile anterior column, PCOs should be considered over 3COs because of their decreased risk of blood loss and complications.

Preoperative and postoperative sagittal plane analysis in adult idiopathic scoliosis in patients older than 40 years of age

BACKGROUND CONTEXT

Most of the papers correlate sagittal radiographic parameters with health-related quality of life (HRQOL) scores for patients with scoliosis. However, we do not know how changes in sagittal profile influence clinical outcomes after surgery in adult population operated for mainly frontal deformity.

PURPOSE

This study aimed to analyze spinal sagittal profile in a population operated on adult idiopathic scoliosis (AS) and to describe variations in sagittal parameters after surgery and the association between those variations and clinical outcomes.

DESIGN/SETTING

This is a historical cohort study.

PATIENT SAMPLE

We included in this study 40 patients operated on AS, older than 40 at the time of surgery (mean age 54.9), and with more than 2-year follow-up (mean 7.4 years).

OUTCOME MEASURES

Full-length free-standing radiographs, Scoliosis Research Society 22 (SRS22) and Short Form 36 (SF36) instruments, and satisfaction with outcomes were available at final follow-up.

METHODS

Sagittal preoperative and final follow-up radiographic parameters, radiographic correlation with HRQOL scores at final follow-up, and association between satisfaction and changes in sagittal profile were analyzed. A multivariate analysis was performed. No funds were received for this article.

RESULTS

Preoperatively, the spinal sagittal plane tended to exhibit kyphosis. Most sagittal parameters did not improve at final follow-up with respect to preoperative values. We saw, after univariate analysis, that worse sagittal profile leads to worse HRQOL, but after multivariate analysis, only spinal tilt (ST) persisted as possible predictor for worse SRS activity scores. Frontal Cobb significantly improved. Most patients (82%) were satisfied with final outcomes. Variations in sagittal profile parameters did not differ between satisfied and dissatisfied patients.

CONCLUSIONS

Although most sagittal plane parameters did not improve after surgery, surgical treatment in AS achieves a high satisfaction rate. Good clinical results do not correlate with improving sagittal plane parameters. Sagittal profile measurements are not helpful to decide surgical treatment in patients with mainly frontal deformity.

A Comprehensive Review of Complication Rates After Surgery for Adult Deformity: A Reference for Informed Consent

OBJECTIVE

An up-to-date review of recent literatures and a comprehensive reference for informed consent specific to ASD complications is lacking. The goal of the present study was to determine current complication rates after ASD surgery, in order to provide a reference for informed consent as well as to determine differences between three-column and non-three-column osteotomy procedures to aid in shared decision making.

METHODS

A review of the literature was conducted using the PubMed database. Randomized controlled trials, nonrandomized trials, cohort studies, case-control studies, and case series providing postoperative complications published in 2000 or later were included. Complication rates were recorded and calculated for perioperative (both major and minor) and long-term complication rates. Postoperative outcomes were all stratified by surgical procedure (ie, three-column osteotomy and non-three-column osteotomy).

RESULTS

Ninety-three articles were ultimately eligible for analysis. The data of 11,692 patients were extracted; there were 3,646 complications, mean age at surgery was 53.3 years (range: 25-77 years), mean follow-up was 3.49 years (range: 6 weeks-9.7 years), estimated blood loss was 2,161 mL (range: 717-7,034 mL), and the overall mean complication rate was 55%. Specifically, major perioperative complications occurred at a mean rate of 18.5%, minor perioperative complications occurred at a mean rate of 15.7%, and long-term complications occurred at a mean rate of 20.5%. Furthermore, three-column osteotomy resulted in a higher overall complication rate and estimated blood loss than non-three-column osteotomy.

CONCLUSIONS

A review of recent literatures providing complication rates for ASD surgery was performed, providing the most up-to-date incidence of early and late complications. Providers may use such data in helping to counsel patients of the literature-supported complication rates of such procedures despite the planned benefits, thus obtaining a more thorough informed consent.

The Sagittal Balance Does not Influence the 1 Year Clinical Outcome of Patients With Lumbar Spinal Stenosis Without Obvious Instability After Microsurgical Decompression

STUDY DESIGN

A retrospective study with retrospective and prospective inclusion of 100 patients.

OBJECTIVE

To determine whether the sagittal balance (SB) influences the clinical outcome of patients with degenerative lumbar spinal stenosis, who underwent microsurgical decompression.

SUMMARY OF BACKGROUND DATA

The SB has become a critical factor for clinical decision making in the surgical treatment of spinal degenerative diseases. However, a frequently recommended sagittal realignment of elderly, multimorbid patients is accompanied by a significant rate of complications. The influence of SB on the clinical outcome of patients with degenerative spinal stenosis, who undergo decompressive surgery is not well understood. The aim of this study was to explore whether the clinical outcome of these patients is related to the SB and whether patients with spinal stenosis and degenerative sagittal imbalance necessitate restoration of the SB in addition to microsurgical decompression.

METHODS

One hundred patients with lumbar spinal stenosis, who received microsurgical decompression, were retrospectively identified and classified according to the severity of sagittal imbalance: (1) normal balance group, (2) minor loss of balance group, and (3) major loss of balance group. Sagittal parameters were determined from preoperative lateral spinal radiographs. As outcome parameters, we analyzed pre- and postoperative visual analogue scales for leg and back pain, walking distance, Oswestry disability index, Roland and Morris disability questionnaire, Odom's criteria, and the SF-36 score.

RESULTS

All groups significantly benefited from surgery concerning leg pain, back pain, and disability in every day's life. There was no difference in patients with decompensated sagittal imbalance compared to patients with normal SB regarding life quality 6 to 24 months after microsurgical decompression.

CONCLUSIONS

Patients with symptomatic degenerative spinal stenosis and excluded major instability significantly benefit from microsurgical decompression regardless of their sagittal spinal balance. Thus, restoration of the SB for patients with symptomatic degenerative spinal stenosis cannot be recommended in addition to microsurgical decompression.

LEVEL OF EVIDENCE

3.

Less invasive corrective surgery using oblique lateral interbody fusion (OLIF) including L5-S1 fusion for severe lumbar kyphoscoliosis due to L4 compression fracture in a patient with Parkinson's disease: a case report

Background

Corrective surgery for kyphoscoliosis patients tend to be highly invasive due to osteotomy. The present case introduce less invasive corrective surgery using anterior oblique lateral interbody fusion (OLIF) technique.

Case presentation

An 80-year-old Japanese man with a history of Parkinson’s disease presented to our hospital because of severe kyphoscoliosis and gait disturbance. Considering the postsurgical complications due to osteotomy, we performed an anterior-posterior combined corrective fusion surgery: OLIF of Lumbar (L) 2-3, L3-4, and L4-5 (Medtronic Sofamor Danek, Memphis, TN, USA) followed by L5-Sacral (S) 1 anterior lumbar fusion via the OLIF approach using an anterior intervertebral cage, and posterior L3-4 and L4-5 facetectomy and posterior fusion using percutaneous pedicle screws from Thoracic (T) 10 to S1 with a T-9 hook system. The surgery was performed in a less invasive manner with no osteotomy, and it improved the sagittal alignments with moderate restoration, which improved the patient’s posture and gait disturbance. The patient showed transient muscle weakness of proximal lower extremity contralateral side to the surgical site, which fully recovered by physical rehabilitation 3 months after the surgery.

Conclusion

The surgical corrective procedure using the minimally invasive OLIF method including L5-S1 fusion showed a great advantage in treating degenerative kyphoscoliosis in a Parkinson’s disease patient in its less-invasive approac.

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 of follow-up

STUDY DESIGN

A retrospective radiographical study.

OBJECTIVE

To compare compensatory behavior of coronal and sagittal alignment after pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) for degenerative kyphoscoliosis.

SUMMARY OF BACKGROUND DATA

There was a paucity of literature paying attention to the postoperative imbalance after PSO or SPO and natural evolution of the imbalance.

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 the last follow-up and radiographical parameters were measured. The lower instrumented vertebral level and level of osteotomy were compared between the patients with and without improvement.

RESULTS

Negative sagittal vertical axis (SVA) was observed in the PSO group postoperatively, implying an overcorrection of SVA. This negative SVA improved spontaneously during follow-up (P < 0.05). Coronal balance was found to worsen immediately postoperatively in the SPO group (P < 0.05). At the last follow-up, spontaneous improvement was observed in 15 patients and the average coronal balance decreased to 16.35 mm. For the 15 patients with improved coronal balance, 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 > 0.05).

CONCLUSION

The overcorrection of SVA is more often seen in the PSO group. The coronal imbalance is more likely to occur in the SPO group. The postoperative sagittal imbalance often spontaneously improves with time. Lower instrumented vertebra at S1 or with pelvic fixation should be regarded as potential risk factors for persistent coronal imbalance in patients with SPO.

LEVEL OF EVIDENCE

3.