Progressive Mid-back Pain and Difficulty Walking
The patient is a 64-year-old male with moderate to severe mid-back pain. He reports his pain is progressively intensifying and radiates anteriorly on his left side. The patient also complains of difficulty walking. His pain is rated 8 using the Visual Analogue Scale (VAS).
Signs of myelopathy: hyper-reflexia and spasticity affect the left lower extremity.
- Organized physical therapy
- Non-steroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, pain medication
Figures 1A through 1C are axial and sagittal CT scans of T6-T7.
There is a calcified disc protruding into the spinal canal, extending from the midline and more prominent to the left. Noted is the location of the ascending aorta at this level.
Figures 1D and 1E are sagittal and axial T2 weighted MRIs. A calcified disc displaces the spinal cord mainly on the left side.
Left-sided T6-T7 calcified disc
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Minimally invasive left direct lateral transthoracic discectomy.
- Lateral decubitus position for a left-sided approach.
- Fluoroscopic guided 6 cm long oblique incision.
- Approximately 5 cm of the rib directly overlying the appropriate thoracic level was dissected subperiosteally from the underlying pleura and neurovascular bundle and removed.
- The lateral sides of the vertebral body and adjoining discs were exposed.
- Sequential tube dilators were inserted.
- The aorta and hemiazygous vein were mobilized anteriorly.
- An expandable tube retractor was fixed to the flexible table-mounted arm assembly.
- Using a micro-surgical technique, the rib head and the costovertebral ligaments at the corresponding levels were removed.
- Before the discectomy, the dura was exposed by removing the pedicle using rongeurs and a high-speed drill, as a guide to the location and proximity of the neural foramen and spinal canal.
- The calcified disc was removed, from anterior to posterior, resected using a drill, curettes, and rongeurs.
- During closure, a chest tube was placed under direct vision.
Post-operative sagittal and axial CT scans and MR images detail the surgical outcome. (Figs. 2A-2E)
After 4 month follow-up, the patient has experienced almost complete resolution of mid-back pain, a VAS of 2, and myelopathy signs are partially improved. The patient has had no spinal curvature deterioration.
Doctors Uribe and Associates describe an interesting and educational case history on a patient with a calcified disc herniation. Overall, they should be commended for the excellent care this patient received concerning this difficult problem.
In summary, the patient is a 64-year-old male with moderate and severe mid-back pain, which is progressively intensifying and radiating along the anterior portion of his left side in a radicular distribution. This pain is intense and rated as an 8/10 using the Visual Analog Scale (VAS). A detailed physical examination noted the patient to have signs of a thoracic myelopathy (spinal cord compression). The presenting features affect his lower extremities and, presumably not in his upper extremity, since this lesion isolates to a thoracic lesion. The patient's imaging studies and MRI showed a large left lateral extradural defect with associated thoracic spinal cord compression, presumably a thoracic disc herniation. The authors recommended obtaining a pre-operative CT scan. This is particularly helpful in this situation where the lesion can be clearly defined and demarcated as a calcified disc herniation. Note the lesion appears to arise out of the disc space.
The patient, therefore, has a symptomatic thoracic myelopathy which is localized by the physical examination and confirmed with the MRI and CT studies of the thoracic spine. The authors advocate a decompressive procedure of the spinal cord due to the progressive symptoms. Unfortunately, there is a no less aggressive technique or non-operative management for this problem of a progressive decline with a mass lesion and thoracic cord compression. In this situation, the authors proceeded with the decompression but, in an attempt to limit the morbidity of the surgical exposure, they used a minimally invasive surgical (MIS) technique. The authors utilized this approach and provided an excellent decompression of the thoracic spinal cord, as seen on the post-operative images.
The reader should be cautioned that there is a learning curve with these techniques and the authors who performed this are quite proficient. Therefore, I would not recommend this approach unless one is very comfortable, proficient, and accomplished with MIS surgery in other regions of the spine. In addition, understanding and having performed thoracic decompressions through open techniques first is important.
The expansion of minimum access spinal decompressions and instrumentation has become more prevalent in spine surgery as we as surgeons strive to produce the maximal surgical benefit (decompression and stabilization) with a minimal incision- or access-related discomfort or trauma. However, as the authors have done is this case, the inherent tenets of surgical decompression must be adhered to and followed. In this case, an anterior mass or vector of spinal cord compression (anterior thoracic disc herniation) should be approached anteriorly or anterolaterally, such as where no decompression or only minimal decompression or retraction is placed on the spinal cord. Therefore, applying the correct surgical principals combined with minimal access approaches, these surgeons were able to perform a difficult surgery and again obtain and excellent outcome.
As we further analyze this specific case, it is interesting to note that the patient had a great degree of mid-back pain radiating over his left side, which is attributed to the thoracic disc herniation. The thoracic spine CT scan, particularly the sagittal reconstruction (Figure 1C), shows the spine to be ankylosed (auto-fused) throughout the patient's entire thoracic spine region. With the ankylosing of the spine one would expect there to be no associated movement at the region of the thoracic spine where the calcified disc was present. In addition, the calcification of the disc suggests that this was a long-standing massed lesion. Therefore, one might expect it to be atypical to present with increasing back pain. However, this scenario is not uncommon for patients to present with a progressive myelopathy due to long-standing cord compression. The complete relief of the patient's pre-operative pain symptoms was a great result, but generally the surgeon's primary goal is to aid the patient's myelopathic symptoms and decompress the spinal cord.
In summary, this is an excellent example of the utilization of a new intervention (MIS techniques) to improve surgical access. However, with understanding and decompressive principles of spine surgery, anterior thoracic spinal cord pathologies should, in general, be approached through an anterior or anterolateral approach. This patient did exceedingly well with the surgery in terms of his pain. However, in my experience, the overall goal should be decompressing the spinal cord understanding that the pain symptoms may not be completely abated using either a minimally invasive or standard approach.