Accuracy of rib cage parameters from 3-Dimensional reconstruction images obtained using simultaneous biplanar radiographic scanning technique in adolescent idiopathic scoliosis: Comparison with conventional computed tomography

Is impaired lung function related to spinal deformities in patients with adolescent idiopathic scoliosis? A systematic review and meta-analysis-SOSORT 2019 award paper

PURPOSE

Some teenagers with adolescent idiopathic scoliosis (AIS) display compromised lung function. However, the evidence regarding the relations between pulmonary impairments and various spinal deformity parameters in these patients remains unclear, which affects clinical management. This systematic review and meta-analysis aimed to summarize the associations between various lung function parameters and radiographic features in teenagers with AIS.

METHODS

A search of PubMed, Embase, PEDro, SPORTDiscus, CINAHL, Cochrane Library, and PsycINFO (from inception to March 14, 2022) without language restriction. Original studies reporting the associations between lung function and spinal deformity in patients with AIS were selected. Independent reviewers extracted data and evaluated the methodological quality of the included studies according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pearson correlation and 95% confidence intervals were calculated using random-effects meta-analysis.

RESULTS

Twenty-seven studies involving 3162 participants were included. Limited-quality evidence supported that several spinal parameters were significantly related to lung function parameters (e.g., absolute value and percent of the predicted forced vital capacity (FVC; %FVC), forced expiratory volume in one second (FEV₁; %FEV₁), and total lung capacity (TLC; %TLC)) in AIS patients. Specifically, meta-analyses showed that main thoracic Cobb angles in the coronal plane were significantly and negatively related to FVC (r =  - 0.245), %FVC (r =  - 0.302), FEV₁ (r =  - 0.232), %FEV₁ (r =  - 0.348), FEV₁/FVC ratio (r =  - 0.166), TLC (r =  - 0.302), %TLC (r =  - 0.183), and percent predicted vital capacity (r =  - 0.272) (p < 0.001). Similarly, thoracic apical vertebral rotation was negatively associated with %FVC (r =  - 0.215) and %TLC (r =  - 0.126) (p < 0.05). Conversely, thoracic kyphosis angles were positively related to %FVC (r = 0.180) and %FEV₁ (r = 0.193) (p < 0.05).

CONCLUSION

Larger thoracic Cobb angles, greater apical vertebral rotation angle, or hypokyphosis were significantly associated with greater pulmonary impairments in patients with AIS, although the evidence was limited. From a clinical perspective, the results highlight the importance of minimizing the three-dimensional spinal deformity in preserving lung function in these patients. More research is warranted to confirm these results.

Factors affecting postoperative pulmonary function deterioration in adolescent idiopathic scoliosis: A prospective study using 3-dimensional image reconstruction by biplanar stereoradiography

This study aimed both to evaluate rib cage parameters in patients with adolescent idiopathic scoliosis (AIS) by three-dimensional (3D) image reconstruction using biplanar stereoradiography (EOS) (EOS Imaging, Paris, France) and identify factors associated with postoperative pulmonary function deterioration (PFD). A total of 67 patients with Lenke type 1 or 2 AIS (59 females and 8 males; mean age, 14.4 years) undergoing posterior corrective fusion with a rod rotation maneuver based on segmental pedicle screw fixation were recruited. 3D images and pulmonary function test results were analyzed preoperatively and at 2 years postoperatively. The following parameters were measured: maximum thickness, maximum width, thoracic index, rib hump, rib cage volume (RCV), spinal penetration index (SPI), endothoracic hump ratio (EHR), vertebra-sternum angle (VSA), rib-vertebra angle difference, vertebral lateral decentering (VLD), forced vital capacity (FVC), and percent predicted FVC (%FVC). PFD was defined as a postoperative %FVC decline of 5% or greater. Patients were divided into two groups, namely PFD and non-PFD. FVC increased from 2.62 L to 2.73 L, while %FVC decreased from 88.7% to 82.7%. The maximum width diminished postoperatively in the PFD group. Patients in the PFD group exhibited a significantly smaller increase in RCV and VLD as well as a significantly smaller decrease in SPI, EHR, and VSA than those in the non-PFD group. The rib cage parameters quantified on 3D images reconstructed using EOS are useful in identifying factors affecting PFD in patients with AIS.

Emerging Technologies in Spinal Surgery: Ultra-Low Radiation Imaging Platforms

BACKGROUND

Spine surgery has seen tremendous growth in the past 2 decades. A variety of safety, practical, and market-driven needs have spurred the development of new imaging technologies as necessary tools for modern-day spine surgery. Although current imaging techniques have proven satisfactory for operative needs, it is well-known that these techniques have negative consequences for operators and patients in terms of radiation risk. Several mitigating techniques have arisen in recent years, ranging from lead protection to radiation-reducing protocols, although each technique has limits. A hitherto-problematic barrier has been the fact that efforts to diminish radiation emission come at the cost of reduced image quality.

OBJECTIVE

To describe new ultra-low radiation imaging modalities that have the potential to drastically reduce radiation risk and minimize unacceptable adverse effects.

METHODS

A literature review was performed of articles and studies that used either of 2 ultra-low radiation imaging modalities, the EOS system (EOS-Imaging S.A., Paris, France) and LessRay (NuVasive, San Diego, CA).

RESULTS

Both ultra-low radiation imaging modalities reduce radiation exposure in the preoperative and perioperative settings. EOS provides 3-dimensional reconstructive capability, and LessRay offers intraoperative tools that facilitate spinal localization and proper visual alignment of the spine.

CONCLUSION

These novel radiation-reducing technologies diminish patient and surgeon exposure, aid the surgeon in preoperative planning, and streamline intraoperative workflow.

Three-dimensional reconstruction image by biplanar stereoradiography reflects pulmonary functional states inadolescent idiopathic scoliosis

This study investigated whether the rib cage parameters estimated based on reconstructed three-dimensional (3D) images with biplanar stereoradiography reflect pulmonary functional states in adolescent idiopathic scoliosis (AIS) patients. A total of 67 Lenke type 1 or 2 AIS patients (59 females and 8 males, mean age 14.4 years) were enrolled. All patients underwent preoperative pulmonary functional tests (PFT) and biplanar stereoradiography. Vital capacity (VC) and forced vital capacity (FVC) pulmonary functional data were collected. Rib-cage parameters (maximum thickness, maximum width, thoracic index (TI), rib hump (RH), rib-cage volume (RCV), spinal penetration index (SPI), endothoracic hump ratio (EHR), vertebra-sternum angle (VSA), rib vertebral angle difference (RVAD), and vertebral lateral decentering (VLD)) were quantified from 3D images. Patients were divided into two groups: restrictive lung disorder (RLD) (%FVC < 80%) and non-RLD (%FVC ≥ 80%). The maximum width and RCV were significantly correlated with VC (p < 0.0001), and FVC (p < 0.0001). RH, EHR, and VSA were negatively correlated with %FVC (p < 0.01). TI, SPI, and RVAD were not correlated with any pulmonary parameters. The maximum widths of RLD patients were significantly shorter than those of the non-RLD patients (218.3 mm vs. 229.7 mm, p < 0.01). The RCV of RLD patients was significantly smaller than that of the non-RLD patients (3.94 L vs. 4.49 L, p < 0.0001). The maximum width and RCV measured by 3D images with biplanar stereoradiography reflected pulmonary functional variables in patients with AIS.

Three-Dimensional Analysis of Preoperative and Postoperative Rib Cage Parameters by Simultaneous Biplanar Radiographic Scanning Technique in Adolescent Idiopathic Scoliosis: Minimum 2-Year Follow-Up

STUDY DESIGN

Prospective study.

OBJECTIVE

This study aimed to investigate the changes in rib cage deformity in adolescent idiopathic scoliosis (AIS) by comparing the preoperative and postoperative three-dimensional (3D) reconstruction images using simultaneous biplanar radiographic scanning technique (EOS) (EOS Imaging, Paris, France).

SUMMARY OF BACKGROUND DATA

EOS data are limited for the analyses of preoperative and postoperative rib cage deformity.

METHODS

A total of 67 Lenke type 1 or 2 AIS patients who underwent surgery (59 females and 8 males) were enrolled in this study. The mean patient age was 14.4 years (range: 11-17 yr). In all patients, posterior corrective fusion was performed with a rod rotation maneuver based on segmental pedicle fixation. Spinal parameters (scoliosis and kyphosis) and rib cage parameters (max thickness, thoracic index (TI), rib hump (RH), surface spinal penetration index (sSPI), end thoracic hump ratio, vertebra-sternum angle, rib vertebral angle difference at the apex, and vertebral lateral decentering), were measured. 3D images were assessed preoperatively and postoperatively at 2-year follow-up.

RESULTS

Both main thoracic (MT) and proximal thoracic scoliosis were significantly corrected (51° to 15°, 30° to 17°, P < 0.0001). The rotation of MT apical vertebrae was also significantly corrected (12° to 5°, P < 0.0001). Thoracic kyphosis (T4-T12) significantly increased (13° to 18°, P < 0.0001). Besides, max thickness, TI, and RH demonstrated significant differences between preoperative and postoperative images (P < 0.01). T8-10 sSPI and end thoracic hump ratio decreased significantly postoperatively (P < 0.05). Although surgery significantly decreased vertebra-sternum angle (P < 0.0001), no significant difference was observed between the preoperative and postoperative rib vertebral angle difference (P = 0.32). Following the surgery, vertebral lateral decentering and rib cage volume were significantly increased (P < 0.0001).

CONCLUSIONS

3D reconstruction of the rib cage using biplanar standing stereoradiography is useful to evaluate preoperative and postoperative rib cage deformity in patients with AIS.Level of Evidence: 2.

EOS® imaging: Concept and current applications in spinal disorders

EOS® imaging is a proprietary imaging technology that was launched in 2007. Based on a gaseous particle detector with a multi-wire proportional chamber, it offers several advantages over other imaging modalities: low dose of radiation, ability to create 3D reconstructions, ability to conduct whole body imaging, high reproducibility in measuring various parameters of alignment and faster imaging time. EOS® imaging is slowly gaining widespread acceptance as its applications in various disorders continue to evolve. It has been found to be particularly useful and has opened up new avenues of research in the field of spinal deformities. This narrative review seeks to provide an overview of the proprietary technology behind EOS® imaging, compare it to existing imaging modalities, summarize its current applications in various spinal disorders and outline its limitations.