Comparison of Rod Thickness in VATS patient questionnaire is an exception and attempts to address this issue. This instrument is able to gauge changes in patients’ post-operative status compared with their pre- operative condition.24 Thus, it serves as an insight into both the efficacy and patient satisfaction associated with the current treatment modality, which is the use of the thin and thick rod construct. It is assumed that there are multiple levels of treatment with resulting characteristic outcomes. While this is simple in theory, in reality the additional data elements associated with the instrument, such as cosmesis, patient satisfaction, achieved correction, and functionality, are all manifested as factorial interactions, interposed bet- ween the surgical treatment and the resulting outcome. To differentiate between these interactions, outcome instru- ments have identified several distinct elements of inquiry and reporting. Thus the resulting success of a treatment modality is measured not only by its ability to correct the deformity but also by the degree to which the patient can perform the tasks of daily living. The SRS-22 form may not specifically ask what particular implant was used (in our case, if whether a thin or thick rod was used), but rather it addresses the outcome brought on by the intervention (what rod was used). Patient-based outcomes as assessed with the SRS-22 questionnaire revealed improvement in the total score and self-image domain in both groups. There was no signifi- cant difference in the scores of both groups. These may be because both groups were treated by minimally invasive thoracoscopic surgery and so post-operative pain and other variables associated with posterior or open anterior surge- ries were lessened, if not avoided altogether. Thoracoscopic correction of Lenke type 1 curves is a safe, effective, and feasible method with results comparable to posterior corrections. Though both the thick and thin rod systems resulted in an acceptable correction rate at the immediate post-operative period, considerable correction loss was observed in the thin rod system at the final follow- up. The thick rod system demonstrated more stability and a better control of thoracic kyphosis. Due to the ability to maintain the correction achieved, the more rigid implant system (thick rod with poly axial screws) is recommended for VATS. A larger prospective series with a longer follow- up is necessary to confirm these preliminary reports. REFERENCES 1. Karami M, Ilharreborde B, Morel E, Fitoussi F, Penneçot GF, Mazda K. Video-assisted thoracoscopic surgery (VATS) for the treatment of scolioticrib hump deformity. Eur Spine J 2007;16: 1373-7. 2. Kim HS, Lee CS, Jeon BH, Park JO. Sagittal plane analysis of adolescent idiopathic scoliosis after VATS (video-assisted thora- coscopic surgery) anterior instrumentations. Yonsei Med J 2007; 48:90-6. 3. 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