Oral Posters: MIS
Presented by: F. Tezuka - View Audio/Video Presentation (Members Only)
F. Tezuka(1), K. Yamashita(1), Y. Takata(1), T. Sakai(1), K. Higashino(1), A. Nagamachi(1), K. Sairyo(1)
(1) Tokushima University, Orthopedics, Tokushima, Japan
Introduction: Percutaneous endoscopic discectomy (PED) is a minimally invasive procedure for the surgical treatment of lumbar disc herniation (LDH), and has a very big merit to the patients. There are some complications such as exiting nerve root injury, dural tear and leakage of the cerebrospinal flow, retroperitoneal and epidural hematoma performing PED with transforaminal (TF) approach. However, fortunately, severe complications such as abdominal and retroperitoneal injuries are almost never reported. This time, we assessed the possibility of abdominal and retroperitoneal injuries in the TF-PED.
Materials and Methods: We assessed preoperative computed tomography (CT) images for the patients who were diagnosed with lumbar disc herniation and underwent TF-PED in our hospital. Subjects are 29 patients, 23 men and 6 female. Average age of the m is 20.9 years old. From the L1-2 to the L5-S1 disc level, using reconstructed axial CT images through center of disc parallel to the caudal endplate through the sagittal and coronal slice, we examined whether there are abdominal organ such as liver, retroperitoneal organs such as kidney, spleen, ascending and descending colon in the posterior area to the tangent line of the posterior edge of the disc in the bilateral side. Then, we decided the safety angle of the trajectory line.
Results: 1) L1-L2 disc level We could see liver in 7 patients, right kidney in 22 patients, left kidney in 24 patients, spleen in 5 patients, and descending colon in 4 patients. Average maximum inclination angle (β angle) of the trajectory of TF-PED without interference with organs were 80.9 degrees in the right side, and 79.2 degrees in the left side. 2) L2-L3 disc level Right kidney in 11, left kidney in 11, ascending colon in 2, and descending colon in 5. β angle were 86.5 degrees in the both sides. 3) L3-L4 disc level Right kidney in 2, left kidney in 1, ascending colon in 3, and descending colon in 3. β angle were 89.0 degrees (right), and 89.1 degrees (left). 4) L4-L5 disc level Right kidney in 1, left kidney in 1, and ascending colon in 3. β angle were 88.1 degrees (right), and 87.1 degrees (left). 5) L5-S1 disc level Abdominal and retroperitoneal organs are not detected in the area.
Discussion: The biggest pitfall of minimally invasive spine surgery is that we could not visualize the anatomical structures during approaching the affected surgical site. We can perform PED under local anesthesia, which requires only 8 mm of skin incision, and also with minimal disruption of the spinal structures including ligaments and muscles by dilating technique. Because operators could not see the anatomical structures hidden under the patient's skin, they should know the individual anatomical structures and assess the risk of possible abdominal and retroperitoneal organ injury before their surgeries. From this result, we found that abdominal and retroperitoneal organs appeared backward than the tangent line of the posterior edge of the disc in the upper lumbar intervertebral disc level. We found that it was risky to approach from far-lateral point horizontally. It is important to assess the possible risk to avoid the severe complication in the wide-spreading PED method.