Lamina Fenestration Technique for Treatment of Thoracic Ossified Ligamentum Flavum: 2-Year Follow-Up Result.

 The incidence of thoracic ossification of ligamentum flavum (OLF) is increasing, and the available surgical techniques were invasive.  To evaluate the surgical outcome and prognostic factors in relation to clinicoradiologic variables with a novel minimally invasive lamina fenestration technique in patients with thoracic OLF.  Between July 2005 and November 2010, 27 levels with 50 lesions in 17 patients were treated with the lamina fenestration technique for the decompression of thoracic OLF. This technique creates a keyhole in the lamina, preserving lower lamina bone, facet joint, and ligamentum flavum. Patient outcome was analyzed using the Japanese Orthopaedic Association (JOA) score and progression of kyphosis on simple X-ray.  All patients were successfully treated with the laminar fenestration technique. There was one dural tear but no neural complication or injury. Mean length of follow-up was 49 months. Mean JOA score improved from 4.88 to 7 ( = 0.000). Six patients had an excellent surgical outcome; 10 had a good surgical outcome according to JOA scoring.  The lamina fenestration technique for the treatment of thoracic OLF had a successful outcome with few complications. This technique can be a minimally invasive surgical option for the treatment of thoracic OLF.