SpineUniverse Case Study Library

Thoracic Disc Herniation

History

The patient is a 58-year-old Caucasian male who presented with a chief complaint of gait disturbance. The gait disturbance had been present for one year, but it had significantly deteriorated in the previous 2 months. The patient reported no pain, no bowel or bladder impairment, and no significant medical history.

Examination

The patient was obese, weighing 225 lbs and measuring 5'11". Motor strength in the lower extremities was normal. Hyper reflexia was apparent in the knees and ankles. A decrease in touch sensation was subjectively noted. Spinal alignment was normal.

Prior Treatment

The patient had not undergone any prior treatment.

Pre-treatment Images

Figure 1 Yoon Thoracic Disc Herniation.jpg

Figure 1: Sagittal and axial pre-operative images showing T7-T8 herniation with cord compression

 

Diagnosis

The patient was diagnosed with a disc herniation at T7-T8.

Suggest Treatment

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Selected Treatment

The patient underwent an XLIF with MIS discectomy and fusion.

Post-treatment Images

 Figure 2 Yoon Thoracic Disc Herniation.jpg

Figure 2: Post-operative image after XLIF with MIS discectomy and fusion procedure

Outcome

The patient had a significant improvement of gait disturbance, which the patient reported as being entirely satisfactory. Radiographs indicated a solid fusion. The patient is now 3 years post-op.

Case Discussion

With the primary complaint of gait disturbance and hyperreflexia, this patient is a candidate for spinal cord decompression at the involved level. The choice of a lateral approach was successful in Dr. Yoon’s hands but may not be widely generalized to this disease.

The lateral retractors provide a perpendicular view to the lateral side of the spine. To safely approach and, more importantly, confirm spinal cord decompression, often a more oblique vantage point may be required. Coming in more anteriorly and visualizing the neural elements directly would provide a higher level of safety.

Either a formal thoracotomy or an endoscopically-assisted discectomy would provide this approach. Although fusion is more difficult endoscopically, it is unclear if fusion is primarily required in this disease process. If fusion was felt to be indicated, the more formal open procedure may be best.

Author's Concluding Comments

Due to the progressive symptoms and significant cord compression, decompression of the spinal cord is the most appropriate treatment. The surgical treatment strategy can vary depending on many factors, including the experience and preference of the surgeon. A laminectomy-only approach to remove the disc is probably not the best option, as it is very difficult to avoid putting the spinal cord at risk to remove the centrally-located disc.

An oblique (posterolateral) approach to this disc herniation is possible by a wide laminectomy and facetectomy and possibly costotransversectomy. This approach would necessitate a posterior fusion and entail significant morbidity.

An anterior approach with a traditional thoracotomy (rib resection) is a fairly standard option and can be used successfully. Finally, the method chosen by the author involved using XLIF retractor system to gain access to the disc without rib resectino or lung deflation. This allowed safe discectomy and more rapid recovery by the patient than would be possible through a standard thoracotomy.

Community Case Discussion (4 comments)

SpineUniverse invites spine professionals to share their thoughts on this case.


This case is an excellent example why orthopedists should be required to include neurology, neuroradiology and neuropathology in their spine training, as Neurosurgeons are required to do.

The thoracic HNP looks entirely incidental. There is no displacement of the cord, no signal change in the cord, and this type if hnp is very commonly seen. Was the patient ever examined carefully? I doubt it. Hyperreflexia is such common incidental finding that I doubt it was significant. Did his gait really improve? One wonders if this wasn't merely wishful thinking.

This case reminds me of an operation looking for a disease. I dont believe that this pt. needed a big operation. He really just needed a careful neurological evaluation. What a perfect example of the problem with contemporary spine care!

Great case and great result!
2 comments:
1. Mini-open thoracotomy is low morbidity compared to formal thoracotomy and gives the same benefit as well as same exposure/view.
2. I don't think these patients need a fusion necessarily. Even with 1cm above and below the disc space and 1cm of posterior to anterior vertebral body resection it surprises me how much vertebrae is left. Postoperative instability and pain without fusion don't seem to be a problem.

This is definitely a surgical case. A transthoracic approach can be avoided to reduce post-operative morbidity. I have now been performing arthroscopic thoracic discectomies since 1996, using posterolateral extra-pleural and extra-spinal approach. I described the approach in a cadaver study - "Posterolateral Arthroscopic Discectomies of the Thoracic and Lumbar Spine" CORR, vol 304: 122-129, July 1994. We have presented the report of clinical results twice at the NASS conferences.

I have used this approach for the last 13 years, and have not encountered any significant complication. Most patients can be discharged after 23 hours. As a routine, I perform non-instrumented interbody fusion, and hold the patient in an extension brace for about 6 weeks. But it is reasonable to perform decompression without fusion.

It seems to me worth repeating that I think it is cavalier, at best, to say that this is "definitely a surgical case". Before subjecting a patient to surgery it is generally a good idea to be certain that the finding on the MRI isn't incidental. In this case, I believe it is most likely incidental and surgery was probably not indicated (I am avoiding the word "definitely").

First, thoracic disc herniations are very common, however symptomatic thoracic disc herniations are rare (see: Neurosurgery 28:180-186, 1991) Here's a good quote: "It is known that the annual incidence of thoracic disc herniations causing neurological deficits is one per 1,000,000 population. However, it has been estimated that 15 to 20% of the population have an incidental thoracic disc herniation visible on MR images" (jns.1998.88.4.0623).

The likelihood that any single surgeon will encounter a large series of symptomatic thoracic disc herniations requiring surgery in a short period of time is so small that one needs to call into question whether or not such a surgeon is operating on incidental findings.

The symptoms of a thoracic disc herniation can be radicular or myelopathic. In this case the "myelopathy" is based upon hyperreflexia at the knees and ankles, and subjective sensory symptoms. So, the patient (presumably) had no sensory level, had normal bowel and bladder, had no Babinski signs, had no clonus, had negative Rombergs, could ambulate normally, and had normal motor strength. His "gait disturbance" is not defined for us. Thus, there were none of the hard findings that we should expect before labeling a patient as being myelopathic.

Isolated brisk reflexes in the knees and ankles are common and often normal. To use this alone as the criteria for surgery is lacking in both judgement and scrutiny. If there was a gait disturbance, then this should be characterized in neurological terms.

Radiographic findings of a symptomatic disc herniation might include signal change in the cord. But, almost certainly, one would at least expect to see some effacement of the spinal subarachnoid space posterior to the cord. The fact that this is normal indicates that the cord is not even being displaced posteriorly by this small herniation. This should make even the most scalpel-happy surgeon think twice before assuming that this finding is causing the subjective symptoms.

The differential diagnostic possibilities for this case are long and complicated, so I won't go through them all. However, at a minimum, an extensive work-up was required to see if anything else (e.g. infectious, inflammatory, etc.) might be present.

The presumption that this patient got better from his subjective symptoms as a consequence of this operation is too easily assumed. A skeptical surgeon should think hard about this.

This type of case presentation does a disservice to the patient population by promulgating false assumptions and promoting extremely aggressive care. I concur that the images after surgery look nice, but the target of the operation should be the patient, not the MRI.

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