Characteristics analysis of Segmental and Regional Lumbar Spontaneous Compensation Post Selective Thoracic Fusion in Lenke 1 and 2 Adolescent Idiopathic Scoliosis

ObjectiveTo explore the characteristics of compensation of unfused lumbar region post selective thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis BackgroundPreserving lumbar mobility in the compensation is significant in controlling pain and maintaining its functions. The spontaneous correction of the distal unfused lumbar curve after STF has been widely reported, but previous study has not concentrated on the characteristics of compensation of unfused lumbar region post selective thoracic fusion.MethodA total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and calculated their curve angles and compensations.ResultsThe current study enrolled 41 females (80.4%) and 10 males (19.6%). 36 patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1±7.7°and 24.1±9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84±5.96°, 3.09±4.54°, 2.30±4.53°, -0.12±3.89° and -1.36±2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22±10.39° and -1.49±5.14°, respectively.ConclusionWhen choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments' compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.

Characteristics Analysis of Segmental and Regional Lumbar Spontaneous Compensation Post Selective Thoracic Fusion in Lenke 1 and 2 Adolescent Idiopathic Scoliosis

Objective To explore the characteristics of compensation of unfused lumbar region post selective thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis Method A total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and calculated their curve angles and compensations.Results The current study enrolled 41 females (80.4%) and 10 males (19.6%). 36 patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1±7.7°and 24.1±9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84±5.96°, 3.09±4.54°, 2.30±4.53°, -0.12±3.89° and -1.36±2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22±10.39° and -1.49±5.14°, respectively.Conclusion When choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments' compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.

Is Lenke Rule About Selective Thoracic Fusion Applicable for Younger Adult Idiopathic Scoliosis Under 40 Years of Age: Comparison With Adolescent Patients

Background To evaluate the surgical outcome of younger adult idiopathic scoliosis patients (YAdIS) with selective thoracic fusion by comparing with adolescent idiopathic scoliosis (AIS). Methods Seventy-two idiopathic scoliosis patients (36 adults and 36 adolescents) treated by posterior-only all-pedicle screw technique at the same institution were retrospective reviewed and matched by curve pattern and curve magnitude. Radiographic parameters were evaluated preoperatively, postoperatively and at final follow-up. Operating time, blood loss, transfusion and complications were noted. Clinical outcome was assessed by Scoliosis Research Society-22 questionnaire (SRS-22). Results The major thoracic curves in YAdIS group and AIS group were 56.3°±9.7°, 53.3°±10.1° and corrected to 17.2°±7.3°, 14.9°±7.5° respectively without significant difference of correction rate (69.3% vs. 72.0%). For the lumbar curve, Cobb angles in two groups were 35.6° ± 10.1° and 31.4 ± 9.2° preoperatively, and was spontaneously corrected to 18.5° ± 9.0° and 12.6° ± 8.2°. Correction rates were 48.0% and 59.8% (P＜0.05). Coronal vertebra alignments (CVA) in YAdIS group were 20.6 ± 9.7 mm before surgery and 16.8 ± 7.9 mm after surgery (P＞0.05), while CVA in the AIS group was 17.8 ± 10.5 mm preoperatively and decreased to 9.7 ± 8.3 mm postoperatively (P＜0.05). However, sagittal parameters showed significant improvements in thoracic kyphosis in both groups (P＜0.05). Complication rates were 13.9% vs. 5.6% without significant difference. Preoperative SRS score was worse in the YAdIS group than the AIS group. However, there were no significant differences between the final SRS score. Conclusions YAdIS patients gained similar correction of major thoracic curve as AIS patients, although the curve were stiffer.However,more extensive release technique needed to be done which was associated with longer operation time hospital stay. YAdIS had more complications,though this difference was not statistically significant. Patients with lower SRS score in YAdIS can also be treated very well with selective thoracic fusion surgery.