Additional Lateral Intermuscular Access to Standard Costotransversectomy Increases Surgical Operability and Exposure in the Resection of Large Median Thoracic Disc Herniations.

Thoracic disc herniations still represent a challenge for spinal surgeons. Their intimate relationship with the spinal cord and the difficult access to the target area are limiting factors even in expert hands.We describe a novel technical variant of the standard costotransversectomy (CTT) approach that utilizes an additional intermuscular corridor between the longissimus and iliocostalis muscles to access the central portion of the spinal canal.An anthropometric study was conducted on neuroimaging in the general population to quantify the working distance, the maneuverability arc, and the surgical angle of incidence recorded on the central canal compartment, as provided by the proposed additional lateral intermuscular access (ALIA) in the CTT approach. The described technique has been applied in the clinical setting. We here report an illustrative case.ALIA allows additional access to the central canal compartment with comparable exposure and surgical operability as those provided by the minimally invasive extracavitary approach (ECA). By respecting the regional muscular and vascular anatomy, it potentially reduces the risk of devascularization damage associated with the standard ECA. The combination of a median and a lateral exposure maintains the advantage of ECA multiangularity, allowing, where necessary, canal decompression and the possibility of easily instrumenting the spine segment.Combining ALIA with a standard CTT optimizes exposure and surgical operability on the central canal compartment, as after performing a standard ECA, but avoiding extensive dissection of the paravertebral tissues and muscles. Median complex thoracic disc herniations represent the main indication for this technical variant.