Global Sagittal Angle and T9-tilt seem to be the most clinically and functionally relevant global alignment parameters in patients with Adult Spinal Deformity

Introduction

Radiographic analysis is necessary for the assessment and the surgical planning in adults with spinal deformity (ASD). Restoration of global alignment is key to improving patient's quality of life. However, the large number of existing global alignment parameters can be confusing for surgeons.

Research question

To determine the most clinically and functionally relevant global alignment parameters in ASD.

Material and methods

ASD and controls underwent full body biplanar X-ray to calculate global alignment parameters: odontoid to hip axis angle (OD-HA), global sagittal angle (GSA), global tilt (GT), SVA, center of auditory meatus to hip axis (CAM-HA), SSA, T1-tilt and T9-tilt. All subjects filled HRQoL questionnaires: ODI, SF-36, VAS for pain and BDI (Beck's Depression Inventory). 3D gait analysis was performed to calculate kinematic and spatio-temporal parameters. A machine learning model predicted gait parameters and HRQoL scores from global alignment parameters.

Results

124 primary ASD and 47 controls were enrolled. T9 tilt predicted the most BDI (31%), hip flexion/extension during gait (36%), and double support time (39%). GSA predicted the most ODI (26%), thorax flexion/extension during gait (33%), and cadence (36%).

Discussion and conclusion

Among all global alignment parameters, GSA, evaluating both trunk shift and knee flexion, and T9 tilt, evaluating the shift of the center of mass, were the best predictors for most of HRQoL scores and gait kinematics. Therefore, we recommend using GSA and T9 tilt in clinical practice when evaluating ASD because they represent the most quality of life and functional kinematic of these patients.

Global malalignment in adolescent idiopathic scoliosis: the axial deformity is the main driver

PURPOSE

To evaluate the global alignment of non-operated subjects with adolescent idiopathic scoliosis.

METHOD

A total of 254 subjects with AIS and 64 controls underwent low dose biplanar X-rays and had their spine, pelvis, and rib cage reconstructed in 3D. Global alignment was measured in the sagittal and frontal planes by calculating the OD-HA angle (between C2 dens to hip axis with the vertical). Subjects with AIS were classified as malaligned if the OD-HA was > 95th percentile relative to controls.

RESULTS

The sagittal OD-HA in AIS remained within the normal ranges. In the frontal plane, 182 AIS were normally aligned (Group 1, OD-HA = 0.9°) but 72 were malaligned (Group 2, OD-HA = 2.9°). Group 2 had a more severe spinal deformity in the frontal and horizontal planes compared to Group 1 (Cobb: 42 ± 16° vs. 30 ± 18°; apical vertebral rotation AVR: 19 ± 10° vs. 12 ± 7°, all p < 0.05). Group 2 subjects were mainly classified as Lenke 5 or 6. 19/72 malaligned subjects had a mild deformity (Cobb < 30°) but a progressive scoliosis (severity index ≥ 0.6). The frontal OD-HA angle was found to be mainly determined (adjusted-R² = 0.22) by the apical vertebral rotation and secondarily by the Lenke type.

CONCLUSIONS

This study showed that frontal malalignment is more common in distal major structural scoliosis and its main driver is the apical vertebral rotation. This highlights the importance of monitoring the axial plane deformity in order to avoid worsening of the frontal global alignment.

A 16-fold increase in organ donation in a Hispanic population

Organ transplantation as a substitute for diseased organs in end-stage organ failure has led to a worldwide increase in this treatment modality, but donation has not kept pace with the demand, despite scientific, social, and government efforts. For many years, Hispanic donation in Puerto Rico was meager and lagged behind major centers in North America and Europe. Studies signaled mostly cultural factors in this limited donation. We report a 16-fold increase in organ donation with the development of a formal procurement organization tailored to a local culture.

METHODS

The 30-year, 1400-transplant experience of the Puerto Rico Transplant Center was divided in three periods: 1977 through 1893, the latter signaling the approval of a transplant law; 1984 through 1995, signaling the commencement of a formal organ procurement organization; and 1996 through 2006. The subset of 2001 to 2006 was used in an additional calculation against 1984 to 1995.

RESULTS

The comparison of the mean deceased donors from 1984 to 1995 with 1998 to 2006 shows a 12-fold increase; and the last 6 years versus 1984 to 1995, a 16.8-fold increase.

CONCLUSION

Cultural and educational obstacles in a given country may be overridden by aggressive administrative and educational approaches and strategic planning tailored to local realities, with improvement in organ transplantation.

Depuration of highway runoff water into grass-covered embankments

The management of polluted road runoff water is an important issue in environmental protection. A strategy could be to perform local depuration by infiltration into the soils of the embankment, but knowledge for designing such systems is lacking. This study aims at discussing the relevant soil properties, by estimating the long-term depuration of road runoff water infiltrating into the sandy soil embankment of the A9 highway in Wallis, Switzerland. This was done by estimating the heavy metals (HM) mass balance of two sites 23 and 12 years old, respectively. The accumulated HM were estimated by soil and GB analyses. The HM input was estimated by average water quality and traffic. The results were discussed using two-dimensional simulation of infiltration and a 14 months in situ monitoring of the runoff from the pavement to the embankment and at the bottom of the embankment. The soil properties were appropriate for both small particle adsorption and filtration. A good match between input and stored pollutant charges was found, and the HM profiles accorded well with infiltration simulation and monitoring results, which showed that 80-100% of the runoff water infiltrated into the embankment. Replacement of the cracked concrete gutters by an infiltration channel made of similar soil is recommended. These results oppose the Swiss guidelines for road-polluted water infiltration, as much more clayey soils are recommended. These later soils are difficult to find in Switzerland, and may allow for preferential flow through macro pores, in contrast to the studied site.