Two-Level Osteotomy for Correcting Severe Ankylosing Spondylitis Kyphosis: Radiologic Outcomes of Different Osteotomy Position-Selection Strategy for Different Type of Patients

Vertebral Column Decancellation for Correcting Cervicothoracic Kyphotic Deformity in Patients With Ankylosing Spondylitis

OBJECTIVE

Surgery to correct the cervicothoracic kyphotic deformity in ankylosing spondylitis (AS) can be associated with serious neurovascular risks. According to the literature, there are no clinical reports documenting the use of vertebral column decancellation (VCD) in the treatment of cervicothoracic kyphotic deformity in patients with AS. The purpose of the present study was to retrospectively analyze and evaluate the effect of VCD on cervicothoracic kyphotic deformity in patients with AS.

METHODS

Records of eight patients with cervicothoracic kyphotic deformity who underwent VCD at C7 in our institution were retrospectively reviewed. The mean duration of clinical follow-up after surgery was 19 months. The cervical lordosis (CL) and C2-C7 sagittal vertical axis (SVA) were meticulously measured on full-length spine radiographs. The chin-brow vertical angle (CBVA) was measured on clinical photographs. Outcome measures utilized included the Neck Disability Index (NDI), the Japanese Orthopaedic Association (JOA) Score, and a Visual Analog Scale (VAS) for neck pain. The data analysis was performed using SPSS version 26.0 for Windows. For paired data adhering to a normal distribution, we utilized paired sample t-tests to analyze preoperative and postoperative imaging parameters. Statistical significance was established at a p value threshold of < 0.01.

RESULTS

All eight patients successfully completed the surgery. With an average VCD osteotomy angle of 47.6° ± 8.1° (±SD), the mean preoperative CBVA was 81.1° ± 17.6° (±SD), while the immediate postoperative value was 19.9° ± 5.7° (±SD). The overall average correction was 61.2° ± 18.9°. The mean preoperative cervical sagittal imbalance was 93.4 ± 27.3 mm (±SD), while the immediate postoperative value was 40.2 ± 18.9 mm (±SD). The overall average correction was 53.2 ± 28.1 mm. None of the eight patients experienced intraoperative complications, including nerve or vascular injury, cerebrospinal fluid leakage, or any other related complications. In the cohort of eight patients, the mean values for estimated blood loss, surgical time, and hospital stay were 1313 mL, 248 min, and 18 days, respectively. In comparison to preoperative scores, statistically significant improvement was noted in all patients in the postoperative period with regard to NDI, JOA, and VAS (p < 0.01, using a paired t-test).

CONCLUSION

The VCD procedure proves to be a dependable and efficient approach for addressing cervicothoracic kyphotic deformities. It achieves remarkable corrections in cervical kyphosis and CBVA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: 2400090375.

Orientation of Osteotomized Vertebrae in 2-Level Pedicle Subtraction Osteotomy Plays a Crucial Role in the Remodeling of Harmonious Sagittal Curve for Severe Thoracolumbar Kyphotic Deformity Caused by Ankylosing Spondylitis

BACKGROUND

Few studies reported the remodeling of harmonious sagittal curve after 2-level pedicle subtraction osteotomy (PSO) for severe thoracolumbar kyphosis in ankylosing spondylitis (AS).

OBJECTIVE

To investigate how the orientation of osteotomized vertebrae (OV) affects the remodeling of harmonious sagittal curve in patients with AS undergoing 2-level PSO.

METHODS

Twenty-six patients treated with 2-level PSO were reviewed. Plumb lines of thoracic apex and lumbar apex, the superior/inferior endplate angle of OV, and OV tilt were measured. Patients with AS were grouped based on the postoperative lumbar lordotic apex (LLA, L3 or L4 vs L5 or others).

RESULTS

The level of thoracic kyphotic apex was positively correlated with that of superior OV postoperatively. Larger sacral slope, L1-L3 lordotic angle, and plumb lines of lumbar apex could be obtained in patients with LLA at L3 or L4, accompanied with larger superior endplate angle of OV and OV tilt of inferior OV ( P < .05). Besides, larger lumbar lordotic angle (LL) was observed in these patients (marginally significant, P = .057). For patients with relocated LLA at L5 or others, lower pelvic incidence was observed, accompanied with significant loss of correction ( P < .05) and worse Visual Analog Scale scores (marginally significant, P = .054) during follow-up.

CONCLUSION

Ventrally leaning inferior OV combined with dorsally leaning superior OV contributed to the most harmonious sagittal curve defined as thoracic kyphotic apex at T8 or above and LLA at L3 or L4. Sagittal curve with LLA at L5 could be acceptable in patients with more severe kyphosis, especially those with low pelvic incidence.

Comparison of One-Level Osteotomy and Two-Level Osteotomy for Thoracolumbar Kyphotic Deformity in Ankylosing Spondylitis: A Systematic Review and Meta-Analysis

BACKGROUND

One- and two-level osteotomies have been used to treat thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). However, the effectiveness and safety of the 2 methods have not been systematically compared, and few studies have reported on which method might be more suitable for treating AS.

METHODS

We performed a systematic literature search. All comparative studies of one- and two-level osteotomy for the treatment of thoracolumbar kyphosis caused by AS were included. Efficacy was determined by the radiographic outcomes, including global kyphosis, sagittal vertical axis, and lumbar lordosis and the Oswestry disability index. The complication rates were used to assess the safety. We analyzed the data using Review Manager software.

RESULTS

A total of 10 studies were included and used for the meta-analysis. We pooled the studies according to the type of data they had reported to evaluate the radiographic correction and incidence of complications. We found that two-level osteotomy provided advantages compared with one-level osteotomy for spinal correction, including global kyphosis and lumbar lordosis. However, the correction was dependent on the degree of preoperative kyphosis. In addition, we found no differences between the 2 groups in the correction of the sagittal vertical axis or improvement in the Oswestry disability index. However, we did find differences in the incidence of neural complications, dural tear, and operative site infection.

CONCLUSIONS

Our findings have shown that one-level osteotomy is safer than two-level osteotomy. For AS patients with nonsevere kyphosis, one-level osteotomy will be sufficient for spinal sequence correction and maintenance of balance, and two-level osteotomy will not be needed. For AS patients with severe kyphosis, two-level osteotomy can be recommended for better orthopedic effects; however, a careful surgical technique is required.

Are Both Preoperative Full‐Spine 3Dimensional Computed Tomography Scans and X‐Ray Films Necessary for Patients with Ankylosing Spondylitis Kyphosis?

Objective

This study is aimed to investigate whether both pre‐operative full‐spine 3Dimensional computed tomography scan (3D CT) and X‐ray film were necessary for patients with severe ankylosing spondylitis (AS) kyphosis deformity.

Methods

The research objects were selected from the inpatients with AS in our hospital from 2017 to 2019. A total of 42 patients were included in the study. On both the synthesized 2Dimensional (2D) lateral radiograph and X‐ray film, the globe kyphosis (GK), the lumber lordosis (LL), the thoracolumbar kyphosis (TLK) and the thoracic kyphosis (TK) were measured. And the angle seventh thoracic vertebra (T7), the angle twelfth thoracic vertebra (T12) and the angle third lumber vertebra (L3) were also measured. Two researchers with professional medical education were randomly selected to perform the measurement method and record the measurement data. Two researchers independently completed, recorded, and evaluated the accuracy and consistency of the measurement data. This study used intraclass correlation coefficient (ICC) to analyze the synthesized 2D lateral radiograph and general X‐ray film of 42 subjects by two researchers, in order to evaluate the consistency of data measurement results between the examiners. Through the comparison of the above parameters that the GK, LL, TLK, TK, angle T7, angle T12 and angle L3, the evaluation was made both pre‐operative full‐spine 3D CT and X‐ray film were necessary for patients with severe AS kyphosis deformity.

Results

There was no significant difference between the GK, LL, TLK, TK, angle T7, angle T12, angle L3 on the synthesized 2D lateral radiograph and that on X‐ray film (P = 0.240, 0.324, 0.199, 0.095, 0.421, 0.087, 0.478). Agreement two researchers was excellent with ICC of the GK, LL, TLK, TK, angle T7, angle T12, angle L3 (0.977, 0.969, 0.986, 0.945, 0.947, 0.915, 0.857) on the synthesized 2D lateral radiograph. The Bland–Altman plot results that the measurement results of examiners are reliable and stable.

Conclusion

By estimating the degree of spinal sagittal imbalance and measuring the Cobb angle, we can see that full‐length spine radiographs of the patients are unnecessary for patients with severe AS kyphosis deformity who will or have undergone preoperative spine 3D CT.

Clinical Results of Utilizing the Satellite Rod Technique in Treating Ankylosing Spondylitis Kyphosis

Objective

According to the literature, there are no clinical reports documenting the use of the satellite rod technique in the treatment of ankylosing spondylitis kyphosis. The purpose of this retrospective study was to compare the clinical outcome of patients with ankylosing spondylitis kyphosis who adopted satellite rods versus those who did not.

Methods

Patients with ankylosing spondylitis kyphosis who underwent one or two‐level pedicle subtraction osteotomy (PSO) were reviewed, and total of 119 patients (112 males and seven females, average age 39.89 ± 6.61 years) were eligible and included in this present study. Anterior–posterior and lateral full‐length spine X‐ray films were performed preoperatively and at the two‐year follow‐up visit. Global kyphosis (GK), lumbar lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), and osteotomy angle (OA) were measured. The complications of every group of patients were collected. Pre‐ and postoperative health‐related quality of life instruments, including the Bath Ankylosing Spondylitis Functional Index (Basfi) and Scoliosis Research Society outcomes instrument‐22 (SRS‐22), were recorded. The patients were divided into three groups based on features of their osteotomy including PSO levels and whether the satellite rod technique was applied. Patients who underwent one‐level PSO without the satellite rod technique were categorized in the one‐level group. Patients who underwent one‐level PSO with the satellite rod technique were classified in the satellite rod group. Patients who underwent two‐level PSO without the satellite rod technique were included in the two‐level group. The paired sample t test was used to compare pre‐ and postoperative parameters. One‐way ANOVA was performed for multiple group comparisons.

Results

The average follow‐up time is 29.31 ± 3.66 months. The patients' GK were significantly improved from 46.84 ± 20.37 degree to 3.31 ± 15.09 degree. OS achieved through each osteotomy segment of one‐level group (39.78 ± 12.29 degree) and satellite rods group (42.23 ± 9.82 degree), was larger than that of two‐level group (34.73 ± 7.54 and 28.85 ± 7.26 degree). There was no significant difference between the one‐level group and the satellite rod group in achieving the OS. Thirteen patients experienced different complications (10.92%). Three patients experienced rod fracture in the one‐level group. There was no rod fracture or screw failure in the satellite rod group or the two‐level group.

Conclusion

The satellite rod technique is also recommended for patients who undergo PSO osteotomy to correct ankylosing spondylitis kyphosis deformities.

Anterior Pelvic Plane: A Potentially Useful Pelvic Anatomical Reference Plane in Assessing the Patients' Ideal Pelvic Parameters Without the Influence of Spinal Sagittal Deformity

STUDY DESIGN

Observational study.

OBJECTIVE

This study was aimed at investigating the reliability of anterior pelvic plane (APP) as an anatomical reference plane for assessing the patients' pelvic incidence in patients with ankylosing spondylitis kyphosis deformity.

METHODS

The globe kyphosis (GK), lumber lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), anatomical cervical 7 sacrum angle (aC7SA), and cervical 7 sacrum angle (C7SA) were measured on full-length spine radiography imagines. The pelvic incidence (PI), anatomical pelvic tilt (aPT), and anatomical sacral slope (aSS) were measured on the pelvic synthesized 2D lateral radiography imagines. Because the angle between APP and vertical line was about 4°, Angle1 and tPT were calculated using the following formulas: Angle1 = aC7SA - 4; PT = aPT + 4. According to the study conducted by Vialle, traditional PT (tPT) was calculated using the following widely accepted formula: tPT = PI * 0.37 - 7. Measured PT (mPT) was also measured on the full-length spine radiography imagines.

RESULTS

The data analysis showed that PI, mPT, aSS, aPT, and APPA were 50.83 ± 13.44°, 32.52 ± 4.64°, 41.36 ± 9.46°, 8.56 ± 6.80°, and 23.95 ± 5.17°, respectively. There was no significant difference between the PT and tPT (12.56 ± 6.80, 11.49 ± 4.73; P = .152). So, the results demonstrated that the PT could play the equivalent effect as tPT did for making surgical plans in patients with kyphosis deformity.

CONCLUSION

The pelvic anatomical reference plane had potential to be used in assessing the patients' ideal pelvic incident without the influence of spinal sagittal deformity. The aPT+4 may represent patients' postoperative ideal PT.

The Sagittal Parameters and Efficacy of Pedicle Subtraction Osteotomy in Patients with Ankylosing Spondylitis and Kyphosis Under Different Lumbar Sagittal Morphologies

OBJECTIVE

This study aimed to compare the changes in sagittal parameters and the efficacy of pedicle subtraction osteotomy (PSO) in patients with ankylosing spondylitis (AS) and kyphosis under different lumbar sagittal morphologies and to explore the effect of sagittal morphology on the selection of PSO levels.

METHODS

A total of 24 patients with AS and thoracolumbar kyphosis (TK) who were admitted to the First Affiliated Hospital of Xinjiang Medical University between 2008 and 2019 were enrolled in this study. They were divided into two groups: a lumbar lordosis group (n = 14) and a lumbar kyphosis group (n = 10). Changes in sagittal parameters, lumbar Japanese Orthopaedic Association (JOA) scores, and visual analog scale (VAS) scores for lumbar pain before and after operation were compared between the two groups to evaluate postoperative efficacy.

RESULTS

The preoperative lumbar lordosis (LL) was -29.29 ± 5.40 (lordosis) and 13.50 ± 3.65 (kyphosis) (P < 0.01), and the preoperative sagittal vertical axis (SVA) was 171.35 ± 25.46 (lordosis) and 223.58 ± 21.87 (kyphosis) (P < 0.01). Preoperative global kyphosis (GK) was 75.71 ± 5.26 (lordosis) and 86.30 ± 10.32 (kyphosis) (P < 0.05). All patients in the lordosis group underwent PSO surgery at the twelfth thoracic vertebra (T12) or the first lumbar spinal vertebra (L1), while all patients in the kyphosis group underwent the surgery at the second or third lumbar spinal vertebra (L2 or L3). The differences in postoperative GK, LL, and SVA between the two groups were not significant (P > 0.05). The JOA scores of the two groups increased from 13.00 ± 0.83 (lordosis) and 11.30 ± 0.93 (kyphosis) before surgery to 21.00 ± 0.67 and 19.70 ± 0.60 after surgery (P < 0.05).

CONCLUSION

Preoperative lumbar sagittal morphology needs to be considered when selecting the optimal osteotomy plane. An osteotomy can achieve the greatest success in patients with lumbar kyphosis at L2/L3; for patients with lumbar lordosis, it can achieve satisfactory outcomes at T12/L1.

Combined percutaneous and open instrumentation for thoracolumbar kyphosis correction by two-level pedicle subtraction osteotomy in ankylosing spondylitis

BACKGROUND

A long global thoracolumbar kyphosis is common in ankylosing spondylitis. Surgical correction of fixed sagittal malalignment by pedicle subtraction osteotomy (PSO) might improve disability and quality of life (QoL). Two-level osteotomies represent major procedures with a risk of hemorrhage. Combined open and minimal invasive surgery has not been described and might be considered.

CASE PRESENTATION

A 30-year-old female with ankylosing spondylitis was treated by golimumab and teriparatide. The treatment was stopped during pregnancy which led to vertebral compression fractures and kyphosis of 50° between T11 and L3. A PSO was planned at the kyphotic apex L2. The second PSO was planned at L4 according to the pelvic incidence of 56°, matching with a spinopelvic alignment Roussouly type 3. A derived full balance integrated method was used to calculate the amount of correction. During the first stage surgery, an open approach was performed from L1 to pelvis and combined with percutaneous cement-augmented instrumentation in already fused segments T5-T12, thus reducing perioperative morbidity. A stepwise approach including L2 PSO closure with temporary rods and L4 PSO with final instrumentation was used. Blood loss was estimated around 1100 ml. The patient was able to walk on the second day after surgery. A secondary anterior fusion with LLI cages from L2 to L5 and an ALIF at L5-S1 were performed because of high non-ossified intervertebral disks to reduce the risk for nonunion and rod fractures. At 2-year follow-up, the patient's QoL had significantly improved and full spine radiographs showed stable normalized sagittal parameters.

CONCLUSION

The combined open and percutaneous approach was feasible and might be considered as an alternative option to conventional open surgery when planning major deformity correction in ankylosing spondylitis.