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

Surgical treatment algorithm for thoracic and lumbar hyperkyphosis in pediatric population

PURPOSE

There is no standardized and universally accepted surgical treatment for thoracic and lumbar hyperkyphosis in children. A surgical treatment algorithm was developed to aid in the choice of the appropriate corrective technique.

METHODS

A retrospective analysis was conducted of patients younger than 18 years who underwent primary correction surgery and posterior fusion for thoracic and lumbar hyperkyphosis. Patients were categorized according to the classification of Rajasekaran et al. and divided into 2 groups: a posterior column osteotomies (PCO) group and a three-column osteotomies (3CO) group. We analyzed the angularity and flexibility of the curve, global sagittal balance, and preoperative neurological status of the patient.

RESULTS

Forty-nine patients were included. The mean age was 12.8 years (1-18) and the mean preoperative kyphosis was 93.5° (40°-175°). In the PCO group (N = 30), the sagittal deformity angular ratio (DAR) was less than 16.5 in 26 patients (86.6%), while in the 3CO group (N = 19), sagittal DAR was greater than 16.5 in 17 patients (89.4%). In the PCO group (N = 28), the T1-Pelvic angle (TPA) was less than 17° in 19 patients (67.8%), while in the 3CO group (N = 15), TPA was greater than 17° in 10 patients (66.6%). Five patients (10.2%) had recent-onset or progressive neurological alteration, all of them (100%) required 3CO.

CONCLUSION

An algorithm for kyphosis was developed based on the classification by Rajasekaran et al., preoperative analysis of the angularity and flexibility of the curve, global sagittal balance and neurological status of the patient, to aid in the choice of the appropriate corrective osteotomy.

LEVEL OF EVIDENCE

IV.

Surgical Correction of Thoracic and Thoracolumbar TB Kyphosis by Posterior Only Approach Using Rajasekaran's Kyphosis Classification

STUDY DESIGN

Prospective analysis of retrospective data.

OBJECTIVES

To analyse the clinical and radiological outcomes of thoracic and thoracolumbar TB kyphosis by a posterior-only approach using kyphosis classification.

METHODS

Patients with thoracic and thoracolumbar spinal TB who underwent posterior-only surgical correction for kyphotic deformity >30° were categorized into Group: A (Active TB) and Group B (Healed TB). Demographic, clinical and radiological data were collected, and kyphotic deformity was classified according to Rajasekaran classification.

RESULTS

52 patients with a minimum 2-year follow-up were included. Group A included 25 patients with mean preop kyphosis of 39.5° (31.2°-53.7°), and Group B included 27 patients with mean preop kyphosis of 85° (44.2°-125.2°). Among 25 patients in Group A, 19 were Type IIIA, and 6 were Type IIA kyphosis. In Group B, 18 patients were Type IIIB, 5 were Type III C, 3 were Type IIA, and 1 was IIIA kyphosis. All patients in group A underwent posterior column shortening by Smith-Peterson Osteotomy, with 14 patients requiring additional anterior column reconstruction. Patients in Group B required Closing-Opening Wedge Osteotomy (18), Halo followed by vertebral column resection (6), disc bone osteotomy (2) and pedicle subtraction osteotomy (1). Mean kyphosis at 2 years follow-up was 20.8° (11.2°-32.8°) in Group A and 53.5° (8.1°- 96.4°) in Group B.

CONCLUSIONS

Correction of kyphosis in spinal TB involves completely different strategies in active and healed disease. Hence, a posterior-only treatment approach using Rajasekaran's kyphosis classification can help surgeons in appropriate decision-making.

Risk predictive score and cord morphology classification for intraoperative neuromonitoring alerts in kyphosis surgery

BACKGROUND

Intraoperative neuromonitoring (IONM) alert is one of the worrying events of kyphosis corrective surgery, which can result in a postoperative neurological deficit. To our knowledge, there is no risk prediction score to predict such events in patients undergoing kyphosis surgery.

PURPOSE

To develop a new preoperative MRI-based cord morphology classification (CMC) and risk prediction score for predicting IONM alerts in patients with kyphotic deformity.

STUDY DESIGN

Retrospective analysis of prospectively collected data.

PATIENT SAMPLE

About 114 patients undergoing surgical correction for kyphotic deformity.

OUTCOME MEASURES

Intraoperative neuromonitoring alerts and postoperative neurological status using AIS grading.

METHODS

Kyphotic deformity patients undergoing posterior spinal fusion were retrospectively reviewed. Based on the morphology of the spinal cord and surrounding CSF in MRI, there are 5 types of cord. Type 1 (normal cord): circular cord with surrounding visible CSF between the cord and the apex, Type 2 (flattened cord): cord with <50% distortion at the apex with obliteration of the anterior CSF; Type 3 (deformed cord): cord with >50% distortion at the apex with complete obliteration of the surrounding CSF; Type 4 (stretched cord): the cord is stretched and atrophied over the apex of the curve. Type 5 (translated cord): horizontal translation of the cord at the apex with buckling collapse of the vertebral column. Preoperative radiographs were used to measure the preoperative sagittal cobbs angle, sagittal deformity angular ratio (S-DAR), sagittal vertical axis (SVA), apex of the curve, and type of kyphosis. Clinical data like the duration of symptoms, clinical signs of myelopathy, neurological status (AIS grade), grade of myelopathy using the mJOA score, and type of osteotomy were documented. Multivariate logistic regression was used to determine the risk factors for IONM alerts and the risk prediction score was developed which was validated with new cohort of 30 patients.

RESULTS

A total of 114 patients met the inclusion criteria. IONM alerts were documented in 33 patients (28.9%), with full recovery of the signal in 25 patients and a postoperative deficit in 8 patients. Rate of IONM alerts was significantly higher in Type 5 (66%), followed by Type 4 (50%), Type 3 (21.1%), Type 2 (11.1%), and Type 1 (11.1%) (p-value<.001). Based on multiple logistic regression, 7 factors, namely preoperative neurological status, mJOA score≤6, presence of signs of myelopathy, apex of the curve above T5, preoperative sagittal cobbs, S-DAR, and MRI-based CMC, were identified as risk predictors. The value for the risk factors varies from 0 to 4, and the maximum total risk score was 13. The cut-off value of 6 had good sensitivity (84.9%) and specificity (77.8%) indicating a high risk for IONM alerts. The AUC of the predictive model was 0.92, indicating excellent discriminative ability.

CONCLUSION

We developed and validated a risk predictive score that identifies patients at risk of IONM alerts during kyphosis surgery. Identification of such high-risk patients (risk score≥6) helps in proper evaluation and preoperative counselling and helps in providing a proper evidence-based reference for treatment strategies.

Can preoperative magnetic resonance imaging be used for sagittal kyphotic flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture?

OBJECTIVE

This study aimed to investigate whether preoperative magnetic resonance imaging (MRI) can be used for sagittal kyphotic (SK) flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture (so-OTLF).

METHODS

The authors evaluated the radiographic data of patients with kyphosis secondary to so-OTLF. All patients underwent posterior corrective fusion surgery in the hospital. Spinal sagittal parameters were measured on standing radiographs preoperatively. The regional kyphosis angle (RKA) was also measured on preoperative supine MRI and intraoperative prone radiographs on the surgical frame. The SK flexibility in patients with kyphosis secondary to so-OTLF was defined as the difference from the RKA measured on the standing radiographs to that measured on the intraoperative prone radiographs or preoperative supine MRI. The difference and the correlation between the SK flexibility measured by these two methods were compared and analyzed.

RESULTS

Thirty-seven patients were included. The RKA measured on standing radiographs, supine MRI, and intraoperative prone radiographs were 48.0°, 34.4°, and 32.0°, respectively. Compared with the RKA measured in standing position, the RKA measured on supine MRI decreased by 13.6° (95% confidence interval 11.4°-15.8°), whereas that measured on intraoperative prone radiographs decreased by 16.1° (95% confidence interval 13.7°-18.5°). A linear correlation existed between the SK flexibility measured on supine MRI and that measured on intraoperative prone radiographs, with a mean difference of 2.4° (R² = 0.912, p < 0.001).

CONCLUSION

The degree of regional kyphosis deformity was reduced by self-reduction of the intraoperative surgical frame. With a predictive value similar to an intraoperative prone radiograph, preoperative supine MRI can be used for SK flexibility assessment in patients with kyphosis secondary to so-OTLF. The ability to predict the intraoperative degree of regional kyphosis deformity with positioning before an operation may help with surgical planning and patient counseling regarding expectations and risks of surgery.

Global realignment after posterior vertebral column resection in severe thoracolumbar post-tubercular kyphosis: correlation with patient-reported outcomes

PURPOSE

To investigate spinal realignment in patients with severe post-tubercular kyphosis (PTK) who underwent posterior vertebral column resection (PVCR) and its correlation with patient-reported outcomes (PROs).

METHODS

Eighty-two patients were included in this study. Spinopelvic parameters (focal scoliosis (FS), coronal balance (CB), sagittal vertical axis (SVA), focal kyphosis (FK), C2-7 lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and pelvic incidence minus lumbar lordosis (PI-LL)) and PROs (Visual Analog Scale (VAS) and Oswestry Disability Index (ODI)) were analyzed. The correlation between spinopelvic parameters and PROs was evaluated.

RESULTS

FK, FS, CL, TK, LL, and PI-LL significantly changed after surgery. FK decreased from pre-operative 108.5 ± 16.4° to 31.8 ± 4.5° at three months after surgery and increased to 38.7 ± 6.6° at final follow-up (P < 0.001). FS decreased from pre-operative 20.9 ± 2.2° to 5.1 ± 2.2° at final follow-up (P < 0.001). CL decreased from pre-operative 7.2 ± 7.3° to 3.3 ± 8.3° at final follow-up (P = 0.002). TK improved from pre-operative - 5.6 ± 7.1° to 12.9 ± 8.2° at final follow-up (P < 0.001). LL decreased from pre-operative 75.5 ± 12.6° to 45.5 ± 7.9° at final follow-up (P < 0.001). PI-LL improved from pre-operative - 24.8 ± 13.4° to 4.8 ± 9.9° at final follow-up (P < 0.001). The improvement of PROs was found to be significantly correlated with the variations of FK, CL, TK, LL, and PI-LL. The multiple regression analysis revealed that FK was an independent predictor for the improvement of VAS and ODI.

CONCLUSIONS

PVCR is effective in treating severe PTK, which can significantly improve patients' clinical and radiographic outcomes. Spine surgeons should pay more attention to reducing the residual kyphosis.

Meeting Report from 2nd ICCBH-ERN BOND Spinal Complications in Children and Adults with Achondroplasia Workshop, Dublin, Ireland, 2nd July 2022

A pre-meeting workshop on spinal complications in children and adults with achondroplasia was held in Dublin, Ireland at the 10th International Conference on Children's Bone Health (ICCBH) 2-5 July 2022. The pathophysiology, natural history and medical/surgical management of thoraco-lumbar kyphosis and spinal stenosis remains poorly described in the literature. The structure of the workshop consisted of lectures, a debate and an interactive round table discussion. In total over 100 delegates affiliated to over 70 institutions from 20 countries were in attendance.

Accelerated anterior vertebral growth resulting in kyphosis correction following posterior spinal instrumented fusion

PURPOSE

To discuss the effect of posterior instrumented deformity correction and fusion on the progressive endochondral ossification of anterior vertebral body in a patient with congenital kyphosis secondary to type 1 vertebral anomaly.

METHODS

A 15-year-old male patient presented with a progressively worsening congenital TL kyphosis of 52° magnitude secondary to a posterior hemivertebra. His pre-operative antero-posterior vertebral height ratio (APVHR) and anterior vertebral body defect ratio (AVBDR) on CT were 38% and 49%, respectively. He underwent posterior instrumented deformity correction with multilevel type 1 Schwab osteotomies and fusion.

RESULTS

Over the next 3 years, his serial imaging revealed progressive endochondral ossification and gradual increase in the dimensions of the vertebral body. At the final follow-up, there was a significant restoration of the deficient anterior vertebral body, and the final APVHR and AVBDR were 81% and 90%, respectively.

CONCLUSIONS

Restitution of posterior column integrity through stabilization can mitigate the compressive stresses across anterior column. Over a period of time, forces restraining the growth of anterior vertebral apophysis are alleviated, and the vertebra can potentially re-grow to near-normal dimensions in pediatric population. This phenomenon could be well-demonstrated in our patient during follow-up.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Vertebral column resection (VCR) at the subapical vertebra for correction of angular kyphosis associated with neurofibromatosis type 1(NF1): a case report

PURPOSE

To describe the process and outcome of vertebral column resection (VCR) at the subapical vertebra for correction of angular kyphosis associated with neurofibromatosis type 1(NF1).

METHODS

A review and summary of the medical history, radiographs, operative procedure, and complications of a 16-year-old male presenting with severe angular kyphosis associated with NF1 with dyspnea.

RESULTS

A 16-year-old male presented with severe angular kyphosis associated with NF1 with dyspnea. Preoperative radiographs demonstrated multiple vertebrae were rotated in the vicinity of the apical vertebra, with a wedge-shaped deformity, dysplasia, T10-T12 kyphotic angle of 160°, and T2-L2 kyphotic angle of 95°. VCR at the L1 vertebra (distal end of the apical vertebra) with bone grafting and internal fixation was performed. Postoperative imaging revealed that the T2-L2 Cobb angle was 20°, denoting a correction rate of 79%. The patient's height increased from 130 to 150 cm. The position of internal fixation was not displaced, and the correction angle was maintained at 2-year follow-up.

CONCLUSIONS

The novel strategy of performing VCR at the subapical vertebra, with posterior displacement of the distal end, and remodeling of the spinal canal is potentially a safe and efficacious option to correct sharp angular kyphosis.

Three-column osteotomy by single-stage posterior approach in congenital and post-tubercular kyphosis: a comparison of outcomes

PURPOSE

To compare the clinical, radiological and functional outcomes of three-column osteotomy (3CO) by a single-stage posterior approach in patients with isolated congenital angular kyphosis (CK) and healed post-tubercular kyphosis (PTK).

METHODS

The hospital records of 30 patients with isolated congenital kyphosis (Group CK) and 51 patients with healed post-tubercular kyphosis (Group PTK), operated at a single centre utilizing a 3CO by a single-stage posterior-only approach, were retrospectively analysed. The two groups were compared with respect to selected demographic variables with clinical, radiological and functional outcome measures at a minimum follow-up of 24 months.

RESULTS

Patients in Group CK (median: 13 years, range: 4-30 years) presented earlier than those in Group PTK (median: 16 years, range: 6-45 years). The apex of the deformity was most often located in the thoracic spine in Group PTK, and in the thoracolumbar or lumbar spine in Group CK. The mean operative time (198.2 ± 31.5 min v/s 174.4 ± 34.5; p = 0.01) and estimated blood loss (859.6 ± 312.2 ml v/s 720.8 ± 187.3; p = 0.04) were significantly higher in Group PTK. While the local kyphosis angle was significantly corrected with surgery in both groups, the correction was significantly better in Group CK-this group also had significantly better overall functional (SRS-22r) scores at a follow-up of 24 months (p < 0.05). The overall complication rate (29.4% v/s 23.3%) and neurological complication rate (9.8% v/s 6.6%) were higher in Group PTK. Permanent neurological deterioration occurred in one patient in each group.

CONCLUSION

Patients with PTK have significantly higher age of presentation, higher operative time and higher complication rate as compared to CK. However, good functional outcomes and kyphosis angle correction can be achieved in both the groups with posterior-only three-column osteotomies.

Osteotomies for the Treatment of Adult Spinal Deformities: A Critical Analysis Review

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Spinal osteotomies are powerful deformity correction techniques that may be associated with serious complications.

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The anatomical spinal osteotomy classification system proposes 6 grades of resection corresponding to different anatomic bone, disc, facet, and ligament interventions.

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Surgeons should be aware of the nuances of 3-column osteotomies with regard to spinal level selection, construct composition, and posterior column reconstruction and closure techniques.

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There is a global tendency toward avoiding 3-column osteotomies as much as possible because of the growing evidence regarding the effectiveness of posterior column osteotomies and halo-gravity traction.

Two-level bilateral ultrasound-guided erector spinae plane block for kyphosis corrective surgery - A case report -

Background

Ultrasound-guided erector spinae plane (ESP) block has been used to provide lumbar analgesia. The craniocaudal spread of local anesthetic in this block can be unpredictable in patients with kyphosis due to backward curvature of the spine, which might prevent longitudinal spread.

Case

This is a case of a 33-year-old male (60 kg) diagnosed with type 3b kyphosis of the thoracolumbar region at the level of L1 who underwent extended pedicle subtraction osteotomy. ESP block was administered at two different levels, one at T12 (above the angle of the kyphosis L1) and another at L3 (below the angle of kyphosis L1), as the curvature of kyphosis can hinder the longitudinal spread of local anesthetic.

Conclusions

Two-level ESP block results in better craniocaudal spread of local anesthetic in a patient undergoing kyphosis correction surgery.

Clinical, radiological and functional outcome of posterior-only three-column osteotomy in healed, post-tubercular kyphotic deformity: a minimum of 2-year follow-up

PURPOSE

To describe clinical, radiological and functional outcomes of patients with post-tubercular healed kyphosis operated by posterior-only three-column osteotomy.

METHODS

The hospital records of 47 patients from a single center, operated for healed, post-tubercular kyphosis were retrospectively analyzed. Deformity correction in all patients was done utilizing a three-column osteotomy by a single-stage, posterior-only approach. Radiological parameters (local kyphosis angle; KA, thoracic kyphosis; TK, lumbar lordosis; LL, pelvic tilt; PT, sacral slope; SS, C7 sagittal vertical axis; C7 SVA, pelvic incidence minus lumbar lordosis; PI-LL), functional scores and clinical details of complications were recorded.

RESULTS

The median age of the study population was 16 years (6-45). The apex of deformity was in thoracic, thoracolumbar and lumbar spine in 22, 19 and 6 cases, respectively. The mean operative time was 197.2 ± 30.5 min and the mean operative blood loss was 701 ± 312 ml. KA (preoperative: 68.2° ± 26.9° v/s postoperative: 29.6° ± 20.3°; p value < 0.0001), C7 SVA (preoperative 20.9 ± 37.9 mm v/s postoperative: 5.5 ± 16.3 mm; p value = 0.005) and TK (preoperative 47.7° ± 33.2° v/s postoperative: 37.8° ± 19.8°; p value = 0.0024) underwent a significant change with surgery. Mean SRS-22r score improved after surgical correction (preoperative: 2.7 ± 0.2 v/s final follow-up: 4 ± 0.2; p < 0.0001) with the maximum improvement occurring in self-image domain. The overall complication rate was 29.7%-including 4 neurological and 10 non-neurological complications. Permanent neurological deterioration was seen in one patient.

CONCLUSION

Three-column osteotomies through posterior-only approach are safe and effective and offer good clinic-radiological and function outcome in post-tubercular kyphotic deformity correction.

Radiographic and clinical outcomes of surgical treatment of Kümmell's disease with thoracolumbar kyphosis: a minimal two-year follow-up

BACKGROUND

Up to now in the surgical treatment of Kümmell's disease combined with thoracolumbar kyphosis, little research has focused on the evaluation of the imaging and clinical outcomes of restoring the normal alignment and sagittal balance of the spine. This study aimed to evaluate the short to mid-term radiographic and clinical outcomes in the treatment of Kümmell's disease with thoracolumbar kyphosis.

METHODS

From February 2016 to May 2018, 30 cases of Kümmell's disease with thoracolumbar kyphosis were divided into group A and B according to whether the kyphosis was combined with neurological deficits. All of the cases underwent surgical treatment to regain the normal spinal alignment and sagittal balance. The radiographic outcomes and clinical outcomes of the cases were retrospectively evaluated. The sagittal imaging parameters including sagittal vertebral axis (SVA),thoracic kyphosis (TK),thoracolumbar kyphosis (TLK),lumbar lordosis (LL),pelvic incidence (PI),pelvic tilt (PT),and sacral slope (SS) before operation,immediately after operation,and the last follow-up of each case were measured and evaluated. The clinical results included the Oswestry Disability Index (ODI) and the Numerical Rating Scale (NRS) of the two groups. Statistical software SPSS21.0 was used to analyze the data.

RESULTS

In group A: Mean SVA before operation was 75 mm and 26.7 mm at the final postoperative evaluation (P = 0.000); Mean TLK before operation was 39°, and 7.1° at the final postoperative evaluation (P = 0.000); Mean NRS before operation was 4.7, compared with 0.9 at the final postoperative evaluation (P = 0.000). In group B: Mean preoperative SVA was 62.5 mm and decreases to 30.7 mm at the final postoperative evaluation (P = 0.000); Mean TLK before operation was 33°, and 9.7° 2 years post-operation (P = 0.000); Mean NRS prior to surgery was 4.0, and 0.8 at the last follow-up evaluation (P = 0.000). The improvement of the NRS scores of groups A and B was related to the improvement of the cobb angle (P = 0.020); (P = 0.009) respectively.

CONCLUSION

In the treatment of Kümmell's disease with thoracolumbar kyphosis,to restore the normal alignment and sagittal balance can obtain a satisfactory radiographic and clinical short and medium-term effects.

Toward the Development of a Comprehensive Clinically Oriented Patient Profile: A Systematic Review of the Purpose, Characteristic, and Methodological Quality of Classification Systems of Adult Spinal Deformity

BACKGROUND

Existing adult spinal deformity (ASD) classification systems are based on radiological parameters but management of ASD patients requires a holistic approach. A comprehensive clinically oriented patient profile and classification of ASD that can guide decision-making and correlate with patient outcomes is lacking.

OBJECTIVE

To perform a systematic review to determine the purpose, characteristic, and methodological quality of classification systems currently used in ASD.

METHODS

A systematic literature search was conducted in MEDLINE, EMBASE, CINAHL, and Web of Science for literature published between January 2000 and October 2018. From the included studies, list of classification systems, their methodological measurement properties, and correlation with treatment outcomes were analyzed.

RESULTS

Out of 4470 screened references, 163 were included, and 54 different classification systems for ASD were identified. The most commonly used was the Scoliosis Research Society-Schwab classification system. A total of 35 classifications were based on radiological parameters, and no correlation was found between any classification system levels with patient-related outcomes. Limited evidence of limited quality was available on methodological quality of the classification systems. For studies that reported the data, intraobserver and interobserver reliability were good (kappa = 0.8).

CONCLUSION

This systematic literature search revealed that current classification systems in clinical use neither include a comprehensive set of dimensions relevant to decision-making nor did they correlate with outcomes. A classification system comprising a core set of patient-related, radiological, and etiological characteristics relevant to the management of ASD is needed.

Clinical, radiological, and functional outcomes of posterior-only three-column osteotomy in congenital kyphosis : a minimum of two years' follow-up

AIMS

To describe the clinical, radiological, and functional outcomes in patients with isolated congenital thoracolumbar kyphosis who were treated with three-column osteotomy by posterior-only approach.

METHODS

Hospital records of 27 patients with isolated congenital thoracolumbar kyphosis undergoing surgery at a single centre were retrospectively analyzed. All patients underwent deformity correction which involved a three-column osteotomy by single-stage posterior-only approach. Radiological parameters (local kyphosis angle (KA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), C7 sagittal vertical axis (C7 SVA), T1 slope, and pelvic incidence minus lumbar lordosis (PI-LL)), functional scores, and clinical details of complications were recorded.

RESULTS

The mean age of the study population was 13.9 years (SD 6.4). The apex of deformity was in thoracic, thoracolumbar, and lumbar spine in five, 14, and eight patients, respectively. The mean operating time was 178.4 minutes (SD 38.5) and the mean operative blood loss was 701.8 ml (SD 194.4). KA (preoperative mean 70.8° (SD 21.6°) vs final follow-up mean 24.7° (SD 18.9°); p < 0.001) and TK (preoperative mean -1.48° (SD 41.23°) vs final follow-up mean 24.28° (SD 17.29°); p = 0.005) underwent a significant change with surgery. Mean Scoliosis Research Society (SRS-22r) score improved after surgical correction (preoperative mean 3.24 (SD 0.37) vs final follow-up mean 4.28 (SD 0.47); p < 0.001) with maximum improvement in self-image and mental health domains. The overall complication rate was 26%, including two neurological and five non-neurological complications. Permanent neurological deficit was noted in one patient.

CONCLUSION

Deformity correction employing three-column osteotomies by a single-stage posterior-only approach is safe and effective in treating isolated congenital thoracolumbar kyphosis. Cite this article: Bone Joint J 2021;103-B(7):1309-1316.

Neurofibromatosis Type 1 with Severe Dystrophic Kyphosis: Surgical Treatment and Prognostic Analysis of 27 Patients

OBJECTIVE

The aim of the present study was to explore the surgical treatment and prognosis of 27 cases of neurofibromatosis type 1 with severe dystrophic kyphosis.

METHODS

We performed surgical treatment for scoliosis and kyphosis caused by dystrophic curves at Peking Union Medical College Hospital, Beijing, China from December 2015 to December 2017. The study included 21 patients with moderate to severe kyphosis, 12 males and 9 females, with an average age of 14.95 ± 6.05 years. All patients had kyphosis angles greater than 70° and had more than four skeletal developmental defects. A total of 6 patients with severe kyphosis, 2 males and 4 females, with an average age of 12.5 years, had more than five skeletal developmental defects with a kyphosis angle greater than 90° or a lumbar kyphosis angle greater than 40°. According to the patient's own situation, we adopted a low-grade surgery scheme (grades 1 or 2) or a high-grade surgery scheme (grades 3-6). The low-grade surgery was mainly lower articular surface resection or pontodestomy, and the high-grade surgery was mainly apical vertebral body or upper discectomy. All patients were followed up to determine their prognosis.

RESULTS

Statistical analysis showed that there was a significant difference in preoperative and postoperative scores between the two groups (P < 0.05), and scoliosis correction showed that surgical treatment had a significant effect on scoliosis kyphosis. The mean follow-up time was 66.7 months. Follow-up results showed that 50% of complications after internal fixation were related to high-level surgery. Complications included displacement of the titanium cage, removal of the lamina hook, formation of pseudoarthrosis, and internal fixation failure (with a rate of 7.7%-14.3%). In contrast, there were no associated symptoms for low-grade surgery. In addition, the results showed that gender, age, extent of resection, height, and body mass index had no significant effect on preoperative, postoperative, and prognostic indicators of patients (P > 0.05).

CONCLUSION

Early identification of dysplastic scoliosis-related deformities plays an important role in surgical planning and prognosis, and low-level surgical procedures are more favorable for patients' prognosis.

Scoliosis Research Society-Schwab Grade 6 Osteotomy for Severe Congenital Angular Kyphoscoliosis: An Analysis of 17 Cases With a Minimum 2-Year Follow-up

BACKGROUND

For some patients with severe congenital angular kyphoscoliosis (SCAK), 1-level vertebral column resection is insufficient and the Scoliosis Research Society (SRS)-Schwab Grade 6 osteotomy may be necessary. However, the indications and clinical outcomes of SRS-Schwab Grade 6 osteotomy in patients with SCAK have not been investigated in depth.

OBJECTIVE

To investigate the middle-term radiographic and clinical outcomes, and to evaluate the safety of this high technique-demanding procedure.

METHODS

Patients with SCAK undergoing SRS-Schwab Grade 6 osteotomy from 2005 to 2016 followed up at least 2 yr were retrospectively reviewed. The potential indications of SRS-Schwab Grade 6 osteotomy were analyzed. The coronal Cobb angle, segmental kyphosis (SK), deformity angular ratio (DAR), coronal balance, and sagittal vertical axis (SVA) were measured in the preoperative, postoperative, and final follow-up. The intraoperative and postoperative complications were recorded.

RESULTS

A total of 17 patients with SCAK (10 M and 7F) were included, and the mean follow-up was 30.8 ± 16.4 mo. The indications of SRS-Schwab Grade 6 osteotomy were as follows: multiple "pushed-out" hemivertebrae (13, 76.5%) and multilevel anterior block (4, 23.5%). Compared with preoperation, the coronal Cobb angle, SK and SVA at postoperation were significantly improved (P < .05 for all). The mean total DAR was 33.4 ± 9.9 at preoperation. Three patients were found to have postoperative neurological deficit. Rod breakage occurred in 3 patients at 15- to 48-mo follow-up, and revision surgeries were performed. At the last follow-up, firm bony fusion was observed in all patients.

CONCLUSION

The technique-demanding SRS-Schwab Grade 6 osteotomy, if well indicated, could provide satisfying correction of the SCAK deformity.

Management of Proximal Thoracic Kyphoscoliosis with Early Myelopathy in a Young Adult with Neurofibromatosis Type 1: A Case Report and Review of Literature

INTRODUCTION

Neurofibromatosis (NF) 1 is associated with skeletal deformities. Scoliosis is seen in about 10-64% of NF-1 patients. NF-1 may be associated with dystrophic or non-dystrophic type of curve. There are technical difficulties in treating large dystrophic curve with proximal thoracic kyphoscoliosis in NF-1. This case report and subsequent review of literature attempts to provide a line of management for such difficult lesions.

MATERIALS AND METHODS

We present a case of 22-year-old male with NF-1 who came to us with gradually progressive upper back deformity and signs of early myelopathy for 2-3 months. The patient had a 100° proximal thoracic kyphosis and 100° scoliosis with no neurological deficit and brisk reflexes. A single stage posterior fixation with three column osteotomy at the apex of the curve was performed.

RESULTS

The kyphosis was corrected to 65° from 100, the scoliosis was corrected to 60° from 100. Clinically, the hump in the upper back was visibly reduced. At 1-year follow-up, the patient remained asymptomatic with no loss of correction and implant breakage on X-ray.

CONCLUSION

Large dystrophic proximal thoracic kyphoscoliosis is a difficult lesion to treat and can be managed with an all posterior approach, achieving good cosmetic and neurological outcomes, as demonstrated by this case.

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.