Electronic Thesis and Dissertation Repository

Thesis Format



Master of Science




Bailey, Chris

2nd Supervisor

Rasoulinejad, Parham


Posterior spinal surgery through either a decompression or additional fusion procedure is the widely accepted standard of care for patients presenting with cauda equina syndrome (CES) secondary to massive disc herniation. A plethora of literature has been published regarding post- surgical outcome, particularly in regards to improvement of lower sacral nerve symptoms in relation to timing of surgery. There is a paucity of data with regards to long term clinical outcomes in patients between the decompression and decompression and fusion groups. We initially hypothesized was that there would be no longer term clinical differences in outcome between the two groups, which was the objective of this thesis. The initial post-operative data showed no statistically significant difference between the decompression and fusion groups with regards to lower extremity weakness, presence of radicular symptoms, and improvement in lower sacral symptoms, those being bladder, bowel, and sexual function. Our long-term follow up cohort yielded patients the decompression group alone and showed general trends of improvement from their initial presentation in the aforementioned domains.

Summary for Lay Audience

Cauda equina syndrome (CES) is a debilitating condition from compression of the nerves in the lower portions of the spine. This compression can be from a variety of pathologies, but massive disc herniation will be the focus of this thesis. The compression of the nerves leads to a constellation of symptoms that are seen clinically, which include lower extremity motor difficulties, changes in sensation in the lower extremities, as well as changes in bladder, bowel, and sexual function. This specific condition is extremely rare and is thought to account for less than 5% of all lumbar spine surgeries with new cases presenting in the range of 1 in 33,000 to 1 in 100,000. The goals of therapy are to relieve the compression on the nerves, which is achieved through a posterior spinal surgery. This surgery usually involves removing a piece of the bone in the back of the spine to allow for decompression around the sac filled with the nerves, as well as removing parts of the herniated disc material that is contributing to the compression. In some cases, patients have pre-existing spinal deformity, or a large amount of disc needs to be removed along with a wider decompression that may affect the overall stability of the spine. In these cases, a fusion procedure is added to help address this. In this procedure, screws are placed into the building blocks of the spine called vertebrae with metal rods that are placed into the screw heads to hold things in place.

The decompression procedure is shorter in terms of operative time, and thereby can have the added benefit of lower infection rates, and theoretically lower complications long term. In addition, given the lack of implanted hardware, there is a lower cost and risk for problems at the vertebral levels that are close by, known as adjacent segment disease. However, it has been seen in the past that lumbar fusion can help with lower back pain, which is something that is seen in the population presenting with cauda equina syndrome. To truly understand the clinical differences, we arranged long term in person follow up and administered questionnaires that allowed us to document a variety of different functional domains, from self-care to exercise tolerance to name a few, and return of control of their bladder and bowel function alongside return of power in their legs. We initially found that there was no true difference between the two procedures in the shorter-term post operative follow-up and that overall longer-term trends in the decompression alone group were positive.