Transthoracic Resection of Thoracic Disc Herniation With Navigation

History

A 70-year-old female, with diabetes mellitus, presented with 6 weeks of bilateral abdominal pain radiating to the umbilicus and progressive bilateral lower extremity weakness. She had significant difficulty standing and was unable to walk. Her bowel and bladder function was normal.

Examination

The patient was awake, alert and oriented. Bilateral lower extremity clonus was 1-2 beats.

Pretreatment Imaging

Figure 1. Sagittal lumbar MRI shows a large central and left T10-T11 disc herniation with severe spinal cord compression. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 2. Axial lumbar MRI shows a large central and left disc herniation at T10-T11 with severe spinal cord compression. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Diagnosis

Severe spinal cord compression and myelopathy.

Selected Treatment

Figure 3. Preoperative fiducial placement in the T11 pedicle for intraoperative localization. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Left thoracotomy to approach the lateral T10-T11 disc.

• Navigation to assist with guidance
• Resection of rib head
• Partial T11 pedicle resection
• Partial wedge corpectomies (~1-2 cm) of the T10 and T11 vertebral bodies adjacent to the disc
• Herniated disc and posterior vertebral body walls pulled into the corpectomy defect
• Interbody cage fusion (morselized rib autograft) and fixation with lateral pedicle screw and rod construct at T10-T11

Figure 4. The spine surgeon and thoracic surgeon pictured exposing the lateral disc space and rib head. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 5. Identification and resection of the left T11 pedicle using navigation. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 6. Checking the depth of the wedge corpectomy and determining cage length with navigation. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 7. Intraoperative photograph of the discectomy and corpectomy defect. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 8. Intraoperative photograph of the fusion construct. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Intraoperative O-arm^© images show the corpectomy defect adjacent to the disc space on post instrumentation (Fig. 9).

Figure 9. Intraoperative O-arm images show the corpectomy defect adjacent to disc space on post instrumentation. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Figure 10. Postoperative x-rays of the fusion construct. Image courtesy of Joshua M. Ammerman, MD, and SpineUniverse.com.

Outcome at 12 Weeks Postop

At the patient's 12-week postop appointment, she is walking with assisted devices.

• Ambulates with a walker when out and uses a cane at home.
• Bilateral lower extremity motor function is 5/5; lower extremity hyperflexion is 4+/5
• Diminished proprioception bilaterally in the lower extremities
• Incision is healed
• Driving
• Fully continent

Surgeons' Rationale: Decision Making

Joshua M. Ammerman, MD

Neurosurgeon

Washington Neurosurgical Associates

• Given the large size of the disc and its central location, an anterior approach was felt to be necessary.
• The decision for arthrodesis was related to the need to perform an aggressive discectomy and guard against the need to perform revision surgery, of a high complexity.
• Preoperative fiducial placement permitted rapid identification of the level of interest.
• Navigation permitted rapid intraoperative guidance for pedicle resection, identification of the foramen, completeness of discectomy and decompression across the spinal canal, graft placement and instrumentation without the use of fluoroscopy.

Peer Case Discussion

James S. Harrop, MD, FACS

Professor, Departments of Neurological and Orthopedic Surgery

Thomas Jefferson University

Dr. Ammerman and his team are congratulated for the great care their patient received. There are several excellent points that they discuss in this case which I would like to highlight and commend them for noting.

First, on the physical examination, they noted long track signs and weakness, which localized the compression to the thoracic spinal cord. The MRI localizes the disc herniation at T10-T11, but what is very important is that this was counted from the sacrum since the lumbar spine was visualized. About 20% of patients will have an abnormal number of thoracic/lumbar vertebrae and therefore, when counting from the top on the MRI and from the bottom in the operating room will lead to a wrong level surgery. Therefore, if the patient had only a thoracic MRI—either a scout film, radiographs of the entire spine—localizing the level pre-operatively (which was also done in this case) should be done.

Second, all thoracic disc herniations are not the same, and the author noted the multiple approaches to decompress the spinal cord. I agree that with a large central disc herniation, the safest approach is an anterior resection (actually, not true anterior but anterolateral). This is because with this approach, there is no manipulation of the injured spinal cord.

Third, they performed an aggressive decompression of the bone such to access the disc herniation. I also like to access the spinal column above and below the lesion with a partial corpectomy to minimize manipulation of the spinal cord.

Overall, an excellent decompression and recovering patient.