Orthopedic Surgery

Sept. 18, 2018

Mayo Clinic offers a new, less invasive technique for lumbar fusion. Using cortical-based trajectory screws, the surgery can achieve similar results to open lumbar fusion but with a smaller incision and faster recovery.

"This cortical technique allows us to perform lumbar fusion without the extensive soft tissue and muscle dissection that typically takes place with standard lumbar fusion," says Arjun S. Sebastian, M.D., an orthopedic surgeon at Mayo Clinic in Rochester, Minnesota. "Patients generally bounce back more quickly from surgery, and sometimes go home the day after. These patients tend to do so well after surgery that I have to caution them not to overdo it."

The less invasive technique can be especially beneficial for people with osteoporosis and patients who need revision surgery. "This type of screw utilizes primarily the cortical tract, so it provides better fixation in osteoporotic bone. In patients with prior lumbar fusion who need the adjacent segment fused, these cortical trajectory screws can be placed in a less invasive way and connected to the old fusion construct with more ease than a traditional pedicle screw," Dr. Sebastian says.

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Surgery using cortical-based trajectory screws

Surgery using cortical-based trajectory screws

A. Preoperative radiograph demonstrates a degenerative spondylolisthesis at L3-L4 with partial disk collapse. The patient presented at Mayo Clinic with severe osteoporosis and neurogenic claudication secondary to tricompartmental lumbar stenosis. B and C. Postoperative radiographs demonstrate restoration of disk height and correction of spondylolisthesis. Four months after surgery, the patient has had complete resolution of her back and lower extremity pain, and has returned to her normal activities.

Surgery using cortical-based trajectory screws is done through a traditional midline incision. The screws obtain a four-point fit between the dorsal cortex at the site of insertion, medially oriented posterior pedicle wall, laterally oriented anterior pedicle wall and curvature of the vertebral body wall.

The orientation of the screws away from the neural elements potentially lowers the risk of postoperative radiculitis. In addition, the minimally invasive insertion of screws laterally through the pedicle reduces the risk of injury to the medial branch nerve. "At Mayo we are very focused on patient outcomes," Dr. Sebastian says. "That's why we drive ourselves to innovate and adopt new techniques."

Patients also benefit from Mayo Clinic's multidisciplinary approach. Every patient scheduled for lumbar fusion has bone mineral density testing. If osteoporosis is identified, an endocrinologist works with the patient to improve bone quality. Mayo's orthopedic surgeons also meet weekly with neurosurgeons to confer on spinal cases.

"We share ideas and knowledge," Dr. Sebastian says. "This type of collaboration leads to the adoption of new techniques that leads to better patient care and outcomes."