Microendoscopic posterior decompression for the treatment of XXXX caused by ossification of the ligamentum flavum: a technical report.

@entity1 @entity602
PURPOSE: Ossification of the ligamentum flavum (OLF) is a common cause of progressive @entity602 in East Asia. Good surgical results are expected for @entity1 who already show @entity602 . Surgical decompression using a posterior approach is commonly used to treat OLF. This study investigated the use of microendoscopic posterior decompression for the treatment of thoracic OLF. METHODS: Microendoscopic posterior decompression was performed on 9 @entity1 with @entity602 . @entity1 had a mean age of 59.8  years and single-level involvement, mostly at the T10-11 and T11-12 vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. A tubular retractor and endoscopic system were used for microendoscopic posterior decompression. Midline and unilateral paramedian approaches were performed in 2 and 7 @entity1 , respectively. Intraoperative motor evoked potentials (MEPs) of 7 @entity1 were monitored. Pre- and postoperative neurological status was evaluated using the modified Japanese Orthopaedic Association (mJOA) score. RESULTS: Thoracic OLF for all @entity1 were classed as bilateral type with a round morphology. Improvement of MEPs at least one muscle area was recorded in all @entity1 following posterior decompression. A dural tear in one @entity1 was the only observed complication. The mean recovery rate was 44.9  %, as calculated from mJOA scores at a mean follow-up period of 20  months. CONCLUSIONS: Microendoscopic posterior decompression combined with MEP monitoring can be used to treat @entity1 with thoracic OLF. The optimal surgical indication is OLF at a single vertebral level and of a unilateral or bilateral nature, without comma and tram track signs, and a round morphology.
