Quantification of Multifidus Atrophy and XXXX Following a Minimally Invasive Microdiscectomy.

@entity1 @entity1560 @entity194 @entity2057 @entity121
BACKGROUND: Multifidus @entity121 and @entity194 have been demonstrated following traditional open spine surgery. The purpose of this study was to quantify multifidus @entity2057 and @entity1560 following a 1-level minimally invasive (MIS) lumbar discectomy. METHODS: Magnetic resonance imaging (MRI) of 24 @entity1 who underwent a primary 1-level MIS microdiscectomy were reviewed. Demographics, operative levels, and time from surgery to imaging were assessed. Total and lean cross-sectional areas (CSA), T1-signal intensity ratio between the multifidus and psoas muscles, and lean-to-total CSA ratio were measured. Pre- and postoperative values were compared within each @entity1 utilizing paired sample T-tests. RESULTS: The mean age was 47.8  14.2 years. MRI was obtained 182.5  194.4 days following index surgery. On the ipsilateral side, total CSA decreased at the index level (-4.9%) and the lean CSA decreased at the index (-6.2%), inferior pedicle (-13.0%), and inferior disc levels (-18.6%). On the contralateral side, no significant decreases in total or lean CSA were demonstrated. T1-signal intensity ratios increased at all levels, but the differences were not statistically significant. The lean-to-total CSA ratio was decreased at the superior disc (-5.2%), inferior pedicle (-8.4%), and inferior disc levels (-17.2%) on the ipsilateral side and at the contralateral inferior disc level (-5.3%). CONCLUSIONS: Primary 1-level MIS discectomy results in minimal short-term @entity194 and @entity1560 of the multifidus at the index level. Total CSA @entity194 was mainly confined to the ipsilateral side at the index level. Lean CSA @entity194 was observed mainly at and below the index level on the ipsilateral side. @entity1560 , as measured by the lean-to-total CSA ratio, ranged 1.2-17.2% on the ipsilateral and 0-5.3% on the contralateral side with greater fat content demonstrated caudally to the surgical level. CLINICAL RELEVANCE: Overall, the majority of the multifidus muscle appears to be radiographically preserved following an MIS lumbar discectomy.
