A comparison of the lenke and king classification systems in the surgical treatment of idiopathic thoracic scoliosis

Choosing the Distal Fusion Levels in Lenke Type 1 Adolescent Idiopathic Scoliosis: How Do the Existing Classifications and Recommendations Guide Us?

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

(a) To compare the recommendations of Lenke and Peking Union Medical College (PUMC) classifications in choosing distal fusion levels in Lenke 1 adolescent idiopathic scoliosis (AIS) curves and (b) to analyze whether the variability in distal fusion levels influences treatment outcomes.

METHODS

Hospital records of Lenke 1 AIS patients operated for single stage, posterior-only deformity correction were analyzed. Distal fusion levels recommended by Lenke and PUMC classifications were calculated and were compared with the actual distal fusion levels. The study population was divided based on whether the actual distal fusion levels were in agreement, shorter or longer than those recommended by Lenke classification. Subgroup analysis of Lenke 1C curves was done. The groups were compared with regard to the following outcome measures: Cobb angle correction, postoperative sagittal vertical axis, postoperative C7 offset, and Scoliosis Research Society-22r (SRS-22r) score at 24 months.

RESULTS

The distal fusion levels recommended by the 2 classifications were in agreement in 92 of 104 cases. In all the cases with disparity, Lenke classification recommended shorter fusions than the PUMC classification. No statistically significant difference was observed in the outcome measures-whether the actual distal fusion levels were in agreement, shorter, or longer than those recommended by the Lenke classification or whether or not the recommendations for selective fusion of any of these classifications were adhered to.

CONCLUSION

Lenke classification can save fusion levels without compromising on treatment outcomes when compared with PUMC classification. Variability in choice of distal fusion levels is not clinically significant at 24-month follow-up.

ADOLESCENT IDIOPATHIC SCOLIOSIS AND SIMILAR CONDITIONS: THREE-DIMENSIONAL CLASSIFICATION

ABSTRACT Objective: To create a new comprehensive, three-dimensional, applicable classification for Adolescent Idiopathic Scoliosis and similar conditions. Methods: The Three-Dimensional Classification was created with three components: the first, the quantitative factor, divides into three types according to the number of curves; the second, the locator factor defines the most structured point of the curve; and the third, the sagittal factor, evaluates the overall sagittal plane. To test the new classification, we studied the images of 99 patients comparing the intra- and interobserver agreement and reproducibility index of the Three-Dimensional Classification with that of Lenke. Results: It can be stated that, overall, the agreement between the three evaluators in relation to the Three-Dimensional Classification and that of Lenke in this series was considered very good. Conclusions: The case study showed a significant difference in the percentages between the two Classifications. In the evaluation of thoracic kyphosis, the Three-Dimensional Classification defined 26.6% of the cases as hyperkyphosis and 61.6% as normal, whereas the Lenke Classification defined 6.06% as hyperkyphosis and 84.18% as normal. However, in the global comparative analysis of the methods, the Three-Dimensional and Lenke systems presented statistically the same levels of agreement, since the values of the confidence intervals overlap. Level of Evidence II; Retrospective study.

The clinical importance of sacral slanting in patients with adolescent idiopathic scoliosis undergoing surgery

BACKGROUND CONTEXT

The phenomenon of sacral slanting has not been assessed in patients with adolescent idiopathic scoliosis (AIS). It could be important in determining distal fusion level.

PURPOSE

The purpose of this study is to clarify sacral slanting and to reveal frequency, character, and clinical importance of sacral slanting in AIS patients who underwent surgery.

STUDY DESIGN/SETTING

Retrospective review of radiographs.

PATIENT SAMPLE

The study included 389 patients who underwent surgery for AIS at a single center.

OUTCOME MEASURES

Slanted angles of sacrum, distal curve types, and postoperative decompensation were assessed in whole spine anteroposterior radiographs.

METHODS

This was a retrospective case series, which included 389 AIS patients who underwent corrective surgeries. The degree of sacral slanting was defined as the angle between the horizontal line and the upper end plate of the sacrum. Distal curves were classified according to the direction of L4 tilt (L4-left type and L4-right type). The frequency, direction, and relationship with curve types were analyzed descriptively. Postoperative changes of sacral slanting were compared by paired t test. Decompensation by distal fusion level and distal curve types was analyzed descriptively. The p value of less than .05 was considered as statistically significant.

RESULTS

The frequency of sacral slanting was 19.5% (76 of 389), 29.6% (115 of 389), and 40.6% (158 of 389) by using criteria of 5°, 4°, and 3°, respectively. The 86.7% showed sacral slanting on the left side. The combination of L4-left type with left-sided sacral slanting was the most frequent (124 of 158, 78.7%). Slanted angles were decreased in some cases after surgery. Decompensation in the coronal plane was observed in 2 of 22 patients (9.1%) with a distal fusion level of L4 but in none of the 70 patients with a distal fusion level of L3.

CONCLUSIONS

Sacral slanting in patients with AIS is a unique and frequently observed finding that has never been researched to date. Most importantly, sacral slanting is a critical consideration in selecting distal fusion level when planning corrective surgery in patients with AIS.

Reliability and reproducibility of interapical distance assessment of the lateral deviation of vertebrae in scoliosis

[Purpose] The purpose of this study was to investigate the interobserver reliability and intraobserver reproducibility of interapical distance (IAD) and to analyze its correlation with the Cobb angle (CA). [Subjects and Methods] IAD, a handy tool for assessment of the lateral deviation of vertebrae with a metric scale, was defined as the horizontal distance between one apical vertebra and its counterpart, the opposite apical vertebra in the case of a double curve and the farthest vertebra in the case of a single curve. Fifty full-length, standing anteroposterior radiographs of "idiopathic scoliosis" were reviewed. Three investigators independently measure the CA and IAD at the same time and remeasured the IAD on the same radiograph a week later. [Results] There was no interobserver difference (reliability) in the measurement of IAD or statistical differences in intraobserver reproducibility for each observer. IAD was well correlated with the CA for each observer (r=0.765, r=0.737, and r=0.764). [Conclusion] IAD is useful when assessing lateral deviation in scoliosis and may be a reliable and reproducible index that is well correlated with the CA, and it can be used as a supplementary measure to describe the overall derangement of scoliosis in the coronal plane.

Experiments with a novel content-based image retrieval software: can we eliminate classification systems in adolescent idiopathic scoliosis?

Study Design Preliminary evaluation of new tool. Objective To ascertain whether the newly developed content-based image retrieval (CBIR) software can be used successfully to retrieve images of similar cases of adolescent idiopathic scoliosis (AIS) from a database to help plan treatment without adhering to a classification scheme. Methods Sixty-two operated cases of AIS were entered into the newly developed CBIR database. Five new cases of different curve patterns were used as query images. The images were fed into the CBIR database that retrieved similar images from the existing cases. These were analyzed by a senior surgeon for conformity to the query image. Results Within the limits of variability set for the query system, all the resultant images conformed to the query image. One case had no similar match in the series. The other four retrieved several images that were matching with the query. No matching case was left out in the series. The postoperative images were then analyzed to check for surgical strategies. Broad guidelines for treatment could be derived from the results. More precise query settings, inclusion of bending films, and a larger database will enhance accurate retrieval and better decision making. Conclusion The CBIR system is an effective tool for accurate documentation and retrieval of scoliosis images. Broad guidelines for surgical strategies can be made from the postoperative images of the existing cases without adhering to any classification scheme.

Taking the shoulders and pelvis into account in the preoperative classification of idiopathic scoliosis in adolescents and young adults (a constructive critique of King's and Lenke's systems of classification)

INTRODUCTION

The surgical strategies to treat idiopathic scoliosis on adolescents and young adults need a basic reliable classification. King's and Lenke's classification are inappropriate because they fail to take shoulders and pelvis into account.

METHODS

We propose the answer for the following three questions: 1. Why are we challenging King's and Lenke's systems of classification? 2. How many frontal and possibly sagittal curves do we need to be able to develop a strategy which is applicable to almost all cases? 3. How should scoliotic curves be classified?

RESULTS

In double thoracic and lumbar (thoracic predominant) scoliosis, the concepts of "pelvis included" and "pelvis excluded" are not simply based on a semantic distinction, but correspond to different physiopathological entities and require different surgical strategies. In double thoracic curves the concepts of "real double thoracic" and "potential double thoracic" curves are keys to obtain post operative shoulder balance. In lumbar scoliosis the concepts of "real lumbar" and "lumbosacral" curves are necessary to compare results of posterior or anterior approach in surgical strategies. The system proposed in this work involves ten basic curves.

CONCLUSION

The surgical strategies used to treat idiopathic scoliosis in adolescents and young adults depend on the school of thought as to whether the anterior or posterior approach is preferable and the extent of the vertebral instrumentation. A consensus system of classification of scoliotic curves is required to compare the results obtained using various methods. This has been done in the improved version of King's system proposed here and should provide an efficient tool for use in comparative studies on surgical methods.