The 90° lateral trajectory to the thoracolum­bar spine allows the surgeon to identify the the­cal sac early during exposure while sparing the nerve roots and intraforaminal radiculomedullary artery [ 3 , 17 , 21 , 22 , 32 , 37 , 45 , 48 ]. This differ- entiates the direct lateral approach from the tra­ditional oblique anterolateral access route (which requires at least a partial corpectomy to visual­ize the thecal sac) as well as the posterolateral extracavitary approach (which entails sacrifi ce of at least one nerve root during VBR). Table-fi xed frame-retractor systems [ 30 , 45 , 48 , 54 ] facilitate less-invasive exposure and create suffi cient work­ing space for the surgeon to perform discectomy, spondylectomy, spinal canal decompression, VBR, comprehensive correction maneuvers, and ventrolateral screw-plate or screw-rod instru­mentation from T3 to L4 [ 3 , 4 , 6 , 17 , 24 – 26 , 40 , 44 – 46 , 48 , 54 , 55 ]. To facilitate the surgeon’s anatomical orientation throughout approaching, canal decompression and spinal instrumenta­tion, the patient is usually placed in a 90° lateral decubitus position. While it is feasible to insert pedicle screws in the lateral decubitus position (especially with spinal image guidance), most surgeons prefer to reposition the patient prone on a bolster frame before commencing with (percu­taneous) posterior pedicle-based fi xation.

skin incision depends on the intended procedure. For monosegmental spondylectomy and VBR, a 5–6 cm incision is adequate. Incisional length is extended to 8 cm for bilevel pathology or 10–12 cm for multiple segments – schematic line drawing). Suffi cient mobilization of the skin and subcutaneous areolar tissue from the outer chest cage is important to permit soft tissue retraction craniocaudally and ventrodorsally during dissec­tion and instrumentation. This will also allow for lateral instrumentation to be placed through additional thoracoports inserted one or two inter­costal spaces above/below the rib resection site – schematic line drawing). An 8 cm rib segment is dissected subperiosteally and removed. The intercostal neurovascular bundle is mobilized off the costal sulcus, covered with a moist sponge and defl ected into the chest cavity to avoid retrac­tion-related intercostal neuralgia. Introducing the frame-retractor blades, the parietal pleural is then mobilized from the chest wall using blunt fi nger dissection or a peanut sponge – schematic line drawing). Mobilization of the parietal pleura is initialized around the rib removal site (i.e., ven­trally and near the supra- and infrajacent ribs) before redirecting the retropleural dissection towards the spine. This will minimize the likeli-