Graduation of the Learning Curve from Small to Smaller: Evolution of Tubular Retractors from 18 mm to 14 mm in Management of Lumbar Disc Herniation

Objective While the utility of 16 mm and 18 mm diameter tubular-retractors in the management of prolapsed intervertebral-disc is well-established, there is no published literature on the use of 14 mm tube. The aim of this study is to retrospectively analyze the feasibility and outcomes of discectomy performed through a 14 mm diameter tube in comparison with 16 mm and 18 mm diameter tubes. Methods Groups A, B and C consisting of the first 40 operated patients with symptomatic lumbar disc herniation using 18 mm, 16 mm and 14 mm tubes respectively between July-2007 and April-2018 were evaluated for VAS (leg pain) and ODI and followed up at 1 week, 6 weeks, 3 months, 6 months and 1-year intervals. Results The mean age in Groups A, B and C was 45.3 years (16-78), 47.15 years (20-78) and 42.15 years (17-65) respectively. The mean VAS in Group A, B and C improved from 7.89, 8.15 and 8.2 to 2.53, 2.4 and 2.34 respectively. The ODI in Groups A, B and C improved from 58.5, 56.4, 54.4 to 28.5, 25.6 and 22.4 respectively. The operative time and blood loss in Groups A, B and C were 106.9±44.9, 74±19.45 and 53.37±12.26 min and 54.75±21.11 mL, 47.5±11.03 mL and 43.75±6.86 mL respectively (p