Welcome. I am not an expert in reading MRIs or other imaging. I'm a novice at it - so bear with me. I'll try to help.
In general when I read your report I can't help but ask if or what disease condition do you have of the Spine or Spinal Canal? Do you have a Congenital anomaly, Ankylosing spondylitis, Scoliosis or less likely maybe a Chiari Malformation?
Fusion of the spine is an unusual finding, unless it's been done surgically. I assume you have not had spinal surgery?
Do you have a basic understand the spine's anatomy? The discs of the spines are named by location and begin at the base of the skull with C (Cervical) and end with L (Lumbar) - T represents Thoracic which lies between C and L. C 1-7, T 1-12 and L 1-5 name the vertebrae of the spine, 35 in total. That provides with with the general locations of issues noted on the MRI.
Above and below each vertebrae are vertebral joints. These joints are called facet joints. These allow safe motion of the spine. They are joined by a thin portion of the neural arch called the pars interarticularis. In between each pair of vertebrae are two small holes called intervertebral foramina. The spinal nerves exits the spinal cord through these holes. When these "holes" are narrowed or compromised they can compress the nerve(s) - obviously causing pain. Basic spine anatomy crash course in anatomy is concluded. There is much more - but it gets complicated.
A syrinx is a rare, fluid-filled neuroglial cavity within the spinal cord. It's filled with a protective watery substance known as cerebrospinal fluid (CSF). This fluid normally flows around the spinal cord and brain - we all have it. However we don't all have a Syrinx. Syrinxes are usually the results of lesions that cause some degree of obstruction of the CSF flow. You may hear the word Syringomyelia. It is the generalized medical term often used when referring to any disorder in which a Syrinx (cyst or cavity) forms within the spinal cord.
Hypertrophy means an increase in size - which depending on what it's referring to can be good or bad. If you're a body builder you want your muscles to hypertrophy - if it's the your heart's ventricular - not so good.
Effacing or effacement means thinning. The subarachnoid space is difficult for me to explain as it is complex. Think of it as the the area (like a vein or artery) that contains the cerebrospinal fluid that feeds and protects your spinal column. Try goggling spinal subarachnoid space - it'll be easier to understand.
Several approaches are used to treat a Syrinx - the causation may play a part in determining the treatment as well as your SX (symptoms). Sometimes it's drained or surgically removed - other times it's monitored for a period of time. Be certain the neurosurgeon has great skills and experience in treating Syrinxs.
The medical term for bone spurs is osteophytes. They are really not spur like - they are smooth over growth of bone. They are considered a marker of spinal degeneration (aging). However they can occur at many ages.
The above is simply definitions of some of the medical terms used in your MRI results. When you put it all together what does it mean? You certainly have some significant factors for back pain - and what the entire picture means only a good Neurosurgeon can explain. Sorry I can't be more definitive.
I would not be surprised if surgical intervention is suggested and maybe well advised. However we all know that spinal surgery should be a considered as a last resort. If this was my MRI - I would seek a second opinion after consulting the physician that ordered it. Educate yourself, as you are now trying to do. Know the terms well so you can speak fluently with the physicians. Ask lots of questions. Know the pros and cons - the goals. What can you expect in 5-10 and 20 years? Research and read all you can. The educated and assertive patient often gets the best care.
If you have a specific question on a term - please feel free to ask. I hope something I have offered has been of help. I wish you the very best as unfortunately I think you may have a difficult road ahead.You have your age in your favor. My heart goes out to your.
I'll look forward to hearing more from you.
Best of Luck,