Change in Sagittal Plane Alignment Following Surgery for Scheuermann's Kyphosis

Bipolar hybrid posterior instrumentation tecnique for the correction of Scheuermann's kyphosis

Scheuermann´s kyphosis (SK) is the most common cause of painful and progressive structural hyperkyphosis in adolescents. Surgical treatment should be considered in cases of refractory pain or progressive deformities. We present the clinical and radiological results obtained using a bipolar, hybrid posterior instrumentation tecnique. We analysed 12 males and 6 females, with mean age of 15.8 years. Minimum follow-up was 2 years. We used transverse process hooks at the cranial level and polyaxial screws for the remaining levels. We did not instrument the periapical segment. We used the sagittal stable vertebra (SSV) as the lower instrumented vertebra (LIV) in most cases, the "barely touched SSV" if the above disc space is lordotic. The mean preoperative kyphosis was 73.6º, mean postoperative kyphosis 44.7º, and mean correction of 28.9º (p = 0.0002). The mean reduction in lumbar lordosis (LL) was 8.9º (p = 0.0018). There were no significant differences in the spinopelvic parameters or sagittal balance. The mean number of instrumented levels was 8.9. Type II osteotomies were necessary in only three patients. Three patients had a cranial sagittal angle greater than 10°, all of them asymptomatic. Postoperatively, all patients had VAS scores less than 2 and SRS-22 scores greater than 4. Hybrid bipolar posterior instrumentation offers adequate curve correction, less operative time, implant density, bleeding, material protrusion and risk of spinal cord injury, leaving a large periapical bed for graft supply. We propose to measure the flexibility of the curve in MRI. In flexible curves (those that correct at least 20% in the supine decubitus position), wide facetectomies offer adequate correction of the deformity.

Flexible posterior vertebral tethering for the management of Scheuermann's kyphosis: correction by using growth modulation-clinical and radiographic outcomes of the first 10 patients with at least 3 years of follow-up

PURPOSE

The present prospective cohort study was intended to present the minimum 3 years' results of flexible posterior vertebral tethering (PVT) applied to 10 skeletally immature patients with SK to question, if it could be an alternative to fusion.

METHODS

Ten skeletally immature patients with radiographically confirmed SK, who had flexible (minimum 35%) kyphotic curves (T2-T12), were included. A decision to proceed with PVT was based on curve progression within the brace, and/or persistent pain, and/or unacceptable cosmetic concerns of the patient/caregivers, and/or non-compliance within the brace.

RESULTS

Patients had an average age of 13.1 (range 11-15) and an average follow-up duration of 47.6 months (range 36-60). Posterior vertebral tethering (PVT) was undertaken to all patients by utilizing Wiltse approach and placing monoaxial pedicle screws intermittently. At the final follow-up: mean pre-operative thoracic kyphosis and lumbar lordosis improved from 73.6°-45.7° to 34.7°-32.1°. Mean sagittal vertical axis, vertebral wedge angle and total SRS-22 scores improved significantly. A fulcrum lateral X-ray obtained at the latest follow-up, showed that the tethered levels remained mobile.

CONCLUSION

This study, for the first time in the literature, concluded, that as a result of growth modulation applied to skeletally immature patients with SK, flexible PVT was detected to yield gradual correction of the thoracic kyphosis by reverting the pathological vertebral wedging process, while keeping the mobility of the tethered segments in addition to successful clinical-functional results. The successful results of the present study answered the role of the PVT as a viable alternative to fusion in skeletally immature patients with SK.

LEVEL OF EVIDENCE

IV.

Scheuermann's kyphosis: update on pathophysiology and surgical treatment

Scheuermann's Kyphosis (SK) is a rigid spinal kyphosis. Several theories have been proposed concerning its pathogenesis, but it is, to this day, still unknown. It has a prevalence of 0.4-8.3% in the population with a higher incidence in females. Clinical examination with x-rays is needed to differentiate and confirm this diagnosis. Non-surgical management is reserved for smaller deformities and in skeletally immature patients, whereas surgery is recommended for higher deformities. Combined anterior and posterior approach was considered the gold standard for the surgical treatment of this disease, but there is an increasing trend toward posterior-only approaches especially with use of segmental fixation. This study reviews the pathophysiology of SK while proposing a treatment algorithm for its management.

Surgical Procedures Used for Correction of Scheuermann's Kyphosis: A Meta-Analysis

Objectives

Scheuermann's kyphosis can cause severe back pain and cosmetic disorders to patients. Previous studies on surgical procedure selection for correction of Scheuermann's kyphosis have drawn controversial conclusions. Here, a meta-analysis was performed to figure out a better way between anterior-posterior (AP) combined procedures and posterior-only (PO) procedures.

Methods

We searched PubMed database and Ovid database, as well as Cochrane Library (between January 2009 and December 2020, around recent ten years), for studies reporting Scheuermann's kyphosis correction in an anterior way or a posterior way. Random effects meta-analysis regarding correction degrees and incidence of proximal junctional kyphosis (PJK) was performed.

Results

Finally, 13 unique studies including 586 patients (AP: 300; PO: 286) were identified and included for this meta-analysis. Overall, 6 AP cohorts and 10 PO cohorts were pooled regarding the correction degrees of kyphosis in the analysis, respectively. Pooled correction degrees in AP cohorts were 33.31 (95% CI: 27.48–39.15; I² = 86%, P < 0.001) and in PO cohorts were 31.16 (95% CI: 26.97–35.35; I² = 81.1%, P < 0.001). Comparison of correction between AP and PO cohorts did not indicate any significant difference. Likewise, postoperative PJK incidence showed no difference. Back pain can be caused by both AP and PO procedures, but which causes less pain remains to be conclusive. The PO approach showed less blood loss and shorter surgical duration as compared to the AP approach.

Conclusions

In summary, this meta-analysis shows similar treatment effects between AP and PO procedures in correcting Scheuermann's kyphosis, suggesting the advantage of PO procedures due to less blood loss and surgical duration. However, the postoperative complications PJK and distal junctional kyphosis (DJK) cannot be well concluded due to the limitation of existing data.

Sagittal Plane Alignment and Functional Outcomes Following Surgery for Scheuermann Kyphosis

Objective  To evaluate and correlate the pelvic parameters, the sagittal balance (SB), and the functional outcome of the patients submitted to surgical treatment for Scheuermann hyperkyphosis (SK).

Methods  Patients submitted to surgery between January 2005 and December 2016 were included. The following radiographic measurements were obtained: thoracic kyphosis (TK); lumbar lordosis (LL); SB; pelvic incidence (PI); pelvic tilt (PT); and sacral slope (SS). Complications during the follow-up period were recorded.

Results  A total of 19 patients were included (16 males): the mean preoperative kyphosis was of 83°, and the postoperative kyphosis was of 57°. The mean preoperative lumbar lordosis was of 66°, with a postoperative spontaneous correction of 47°. Regarding the preoperative pelvic parameters, the average PI, PT and SS were of 48°,10° and 39° respectively. In the postoperative period, these values were of 50°, 16° and 35° respectively. The preoperative SB was neutral, and it was maintained after the surgical correction. Concerning complications during the follow-up period, three junctional kyphosis were observed–two requiring revision surgery, one nonunion, and one dehiscence of the surgical wound. Regarding the functional results, the average score on the Scoliosis Research Society-22 (SRS-22) patient questionnaire was of 4.04, and we verified that the SB obtained in the postoperative period had no influence on the functional outcome ( p  = 0.125) nor on the postoperative LL ( p  = 0.851).

Conclusion  We verified a spontaneous improvement in the lumbar hyperlordosis at levels not included in the fusion after correction of the TK. Although the postoperative functional results were globally high, we did not find any statistically significant relationship with TK nor LLs. high PI is associated with a greater rate of complications regarding the proximal junctional kyphosis (PJK), and these pelvic parameters should be considered at the time of the SK surgical treatment.

Intraoperative Prone Radiographs During Scheuermann Kyphosis Correction Closely Estimate Standing Thoracic and Lumbar Parameters at 2 Years

BACKGROUND

In patients with Scheuermann kyphosis (SK) undergoing posterior spinal fusion with instrumentation (PSFI), intraoperative lateral radiographs assess deformity correction in the prone position. The relationship between thoracic and (partially un-instrumented) lumbar parameters on prone intraoperative versus standing postoperative radiographs is unknown.

METHODS

Forty-five consecutive patients with SK who underwent PSFI between 2007 and 2014 were reviewed. Thoracic kyphosis (TK), lumbar lordosis (LL), instrumented level kyphosis [upper instrumented vertebrae (UIV)-lower instrumented vertebrae (LIV)], and traditional sagittal parameters were recorded from preoperative standing, intraoperative prone, first outpatient standing, and >2-year standing radiographs and time periods were compared. Exclusion criteria included reduction modification after intraoperative radiographs and postoperative construct revision prohibiting comparison to initial intraoperative radiographs.

RESULTS

Twenty-five patients averaging 16 (12 to 20) years old during surgery with 3.1 (2 to 7) years follow-up met inclusion criteria. Average surgical variables included: 13±1 fusion levels, UIV at T2, LIV at L3, 3.8±1.6 osteotomies per patient, and 43±9% correction of TK. Preoperative TK and LL measured 82 and 76 degrees, respectively. TK on intraoperative (47 degrees), 6-week (49 degrees), and >2-year (50 degrees) radiographs changed significantly only between intraoperative and >2-year radiographs (P=0.03) by just 3 degrees. LL increased 5 degrees from intraoperative prone to 6-week standing radiographs (51 to 56 degrees, P=0.01) without further significant change at >2 years (59 degrees, P=0.09). Instrumented levels (UIV-LIV) had increased kyphosis at 6 weeks (32 to 35 degrees, P=0.01) without further change at >2 years (36 degrees, P=0.06).

CONCLUSIONS

TK on intraoperative prone radiographs during PSFI for SK should match the standing TK ∼6 weeks later. Intraoperative prone LL only slightly increases on early standing radiographs. Assuming a routine postoperative course, intraoperative radiographs slightly underestimate TK (by 3 degrees) and LL (by 8 degrees) on >2-year standing radiographs. These parameters (TK, LL, UIV-LIV) are visualized during surgery and should be used in future studies to predict long-term outcomes.

LEVEL OF EVIDENCE

Level IV-retrospective study.

The effect of pedicle subtraction osteotomy for the correction of severe Scheuermann thoracolumbar kyphosis on sagittal spinopelvic alignment

Purpose

To analyze how pedicle subtraction osteotomy (PSO) treatment of severe Scheuermann thoracolumbar kyphosis (STLK) using pedicle screw instrumentation affects sagittal spinopelvic parameters.

Background

The medical literature on the post-surgical effects of treatments such as Ponte osteotomy is limited, but suggests few effects on spinopelvic profiles. Currently, there is no research regarding changes in sagittal spinopelvic alignment upon PSO treatment in STLK patients.

Methods

We performed a retrospective study on 11 patients with severe STLK. These patients underwent posterior-only correction surgeries with PSO and pedicle screw instrumentation between 2012 to 2017 in a single institute. Patients were measured for the following spinopelvic parameters: global kyphosis (GK), thoracic kyphosis (TK), thoracolumbar kyphosis (TL), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tile (PT), sacral slope (SS), and administered a Scoliosis Research Society-22 questionnaire (SRS-22) pre-operation, post-operation and at final follow-up.

Results

GK improved from a median of 74.1° to 40.0° after surgery, achieving a correction rate of 48.8% with a median correction loss of 0.8°. TK, TL and LL all showed significant difference (P < 0.05) and SVA improved 22.7 (11.6, 30.9) mm post operation. No significant difference was found in pelvic parameters (PI, PT, SS, all P < 0.05). The absolute value of LL- PI significantly improved from a median of 26.5° pre-operation to 6.1° at the final follow-up. 72.7% in this series showed an evident trend of thoracic and lumbar apices migrating closer to ideal physiological segments after surgery. Self-reported scores of pain, self-image, and mental health from SRS-22 revealed significant improvement at final follow-up (all P < 0.05).

Conclusions

PSO treatment of severe STLK with pedicle screw instrumentation can improve spine alignment and help obtain a proper alignment of the spine and the pelvis.

Under-contouring of rods: a potential risk factor for proximal junctional kyphosis after posterior correction of Scheuermann kyphosis

OBJECTIVE

Scheuermann kyphosis (SK) could require surgical treatment in certain situations. A posterior reduction is the most widespread treatment so far, although the development of proximal junctional kyphosis (PJK) is one of the possible complications of this procedure. The contour of the proximal part of the rod could influence the occurrence of PJK in SK patients. The objective of this study was to analyze the impact of the proximal rod contour on the occurrence of a PJK complication in SK patients.

METHODS

This retrospective monocentric study was performed in the Nanjing Spine Surgery Department. All eligible patients had undergone posterior correction surgery with pedicle screws only between 2002 and 2017 and had at least 24 months of follow-up. The presence of PJK was quantified on radiographs using the proximal junctional angle (PJA > 10° at the last follow-up). The authors propose a new radiological parameter to measure the angulation of the proximal part of the instrumentation: the proximal contouring rod angle (PCRA) is the angle between the upper endplate of the upper instrumented vertebra (UIV) and the lower endplate of the second vertebra caudal to the UIV. The patients were analyzed according to the presence or absence of PJK. A t-test, receiver operating characteristic (ROC) curve analysis, and logistic regression analysis were performed for statistical analysis.

RESULTS

Sixty-two patients treated for SK were included in this study. The mean age was 18.6 ± 8.5 years, and the mean follow-up was 42.5 ± 16.4 months. The mean correction rate of global kyphosis was 46.4% ± 13.7%. At the last follow-up, 17 patients (27.4%) presented with PJK. No significant difference was found between the PJK and non-PJK groups in terms of age and other preoperative variables. A significant difference in the postoperative PCRA was found between the PJK and non-PJK groups (8.2° ± 4.9° vs 15.7° ± 6.6°, respectively; p = 0.001). A postoperative PCRA less than 10.1° predicted a significantly higher risk for PJK (p = 0.002, OR 2.431, 95% CI 1.781-4.133).

CONCLUSIONS

Under-contouring of the proximal part of the rods (lower than 10°) is a risk factor for PJK after posterior correction of SK.

Sagittal Spinal and Pelvic Parameters in Patients With Scheuermann's Disease: A Preliminary Study

Background

Sagittal spinopelvic parameters remain poorly defined in patients with Scheuermann disease (SD). For example, although pelvic incidence (PI) should approximate lumbar lordosis (LL) by 10°, this is not true in patients with SD. This retrospective radiographic study was conducted to propose a new mathematical relationship between sagittal spinopelvic parameters in skeletally mature patients with SD.

Methods

The following formula (Δ) was proposed [(thoracic kyphosis - 45°) + (thoracolumbar kyphosis - 0°) + (PI - LL) = ± 10°] and validated with standard spino pelvic parameters in patients with skeletally mature SD without prior spine surgery at 2 centers between 2006 and 2015. The T1 pelvic angle (TPA) was used as a measure of global balance with normal maximum of 15°. Subgroup analysis was performed to compare Δ between balanced (TPA ≤ 15°) and unbalanced (TPA > 15°) patients with SD.

Results

In patients with SD (n = 30), half were female (n = 15), the average age was 39 years, and the average Δ was 2.4°. A significant correlation was discovered between Δ and both TPA (R ² = 0.75) and PI (R ² = 0.69). At TPA of 15°, average Δ was 9.2°. There was also a significant difference between balanced and unbalanced patients (-8.7° ± 11.6° versus 28.2° ± 19.7°, P = .0003).

Conclusions

This study of a new formula (Δ) to evaluate global sagittal balance in patients with SD found that accounting for the kyphosis maintained Δ within ± 10°. Further study is planned to determine whether maintaining and/or restoring a normal Δ is associated with improved outcomes in patients with SD after surgery.

How does the cervical spine respond to hyperkyphosis correction in Scheuermann's disease?

OBJECTIVE

This study aimed to quantify the response of the cervical spine to the surgical correction of Scheuermann's kyphosis (SK) and to postoperative proximal junctional kyphosis (PJK).

METHODS

Fifty-nine patients (mean age 14.6 ± 2.3 years) were enrolled in the study: 35 patients in a thoracic SK (T-SK) group and 24 in a thoracolumbar SK (TL-SK) group. The mean follow-up period was 47.2 ± 17.6 months. Radiographic data, PJK-related complications, and patient-reported outcomes were compared between groups.

RESULTS

The global kyphosis significantly decreased postoperatively, and similar correction rates were observed between the two groups (mean 47.1% ± 8.6% [T-SK] vs 45.8% ± 9.4% [TL-SK], p = 0.585). The cervical lordosis (CL) in the T-SK group notably decreased from 21.4° ± 13.3° to 13.1° ± 12.4° after surgery and was maintained at 14.9° ± 10.7° at the latest follow-up, whereas in the TL-SK group, CL considerably increased from 7.2° ± 10.7° to 11.7° ± 11.1° after surgery and to 13.8° ± 8.9° at the latest follow-up. PJK was identified in 16 patients (27.1%). Its incidence in the TL-SK group was notably higher than it was in the T-SK group (41.6% [n = 10] vs 17.1% [n = 6], p = 0.037). Compared with non-PJK patients, PJK patients had greater CL and lower pain scores on the Scoliosis Research Society-22 questionnaire (p < 0.05).

CONCLUSIONS

Hyperkyphosis correction eventually resulted in reciprocal changes in the cervical spine, with CL notably decreased in the T-SK group but significantly increased in the TL-SK group. Patients developing PJK have increased CL, which seems to have a negative effect on patients' health-related quality of life.

What Are the Indications for Spinal Fusion Surgery in Scheuermann Kyphosis?

BACKGROUND

Surgical indications for Scheuermann kyphosis are variable. We sought to evaluate the characteristics of patients undergoing operative versus nonoperative treatment of Scheuermann kyphosis to better understand current practices and the factors which contribute to the decision for surgical management.

METHODS

Multicenter prospective cohort study. We evaluated consecutive patients presenting with Scheuermann kyphosis. Patients underwent either surgical or nonoperative management according to surgeon and patient discretion. Preoperative patient-reported outcome measures (Scoliosis Research Society and Spinal Appearance Questionnaire scores), demographics, and radiographic characteristics were assessed.

RESULTS

Overall, 150 patients with Scheuermann kyphosis were enrolled, with 77 choosing nonoperative treatment and 73 treated operatively. Compared with the nonoperative cohort, patients treated operatively were older (16.3±2.0 vs. 15.1±2.2, P=0.0004), and had higher body mass index (26.3±7.2 vs. 22.7±6.5, P=0.003), had greater T2-T12 kyphosis (71±14 degrees vs. 61±12 degrees, P<0.001), increased pelvic incidence (46 vs. 41 degrees, P=0.03) and pelvic tilt (10 vs. 3 degrees, P=0.03). There was no detected difference in maximal sagittal Cobb angle in the operative versus nonoperative patients (73±11 vs. 70±12 degrees, P=0.11). Functionally, the operative patients had worse Scoliosis Research Society pain scores (3.7±0.9 vs. 4.1±0.7, P=0.0027) and appearance scores (2.9±0.7 vs. 3.4±0.8, P <0.0001).

CONCLUSIONS

Patients undergoing surgical management of Scheuermann disease were more likely to have large body mass index and worse pain scores. Other factors beyond radiographic measurement likely contribute to the decision for surgical management of Scheuermann kyphosis.

LEVEL OF EVIDENCE

Level II.

Does surgery for Scheuermann kyphosis influence sagittal spinopelvic parameters?

PURPOSE

To analyze changes in sagittal spinopelvic parameters (SSPs) after surgical treatment of Scheuermann's Kyphosis (SK).

METHODS

We analyzed 20 patients affected by SK and subjected to posterior correction of the kyphosis by facetectomy, Ponte osteotomy, fusion and multilevel instrumentation with pedicle screw system. Four spinal and three pelvic parameters were measured: sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS) and pelvic tilt (PT). Analysis of changes in postprocedural SSPs compared to preoperative values was performed.

RESULTS

TK passed from 78.6° preoperatively to 45.8° (p = 0.003). LL passed from 74.5° preoperatively to 53.5° (p = 0.01). No significant changes occurred in SVA, SS, PT and PI compared to preoperative values.

CONCLUSION

We confirm the positive effect of surgery by Ponte osteotomy and posterior spinal fusion on TK and LL in patients with SK. In our experience, pelvic parameters did not change after surgery.