Hi,
thank you for query
There are many possible causes of numbness and tingling:
•     Sitting or standing in the same position for a long time
•     Injuring a nerve (a neck injury may cause you to feel numbness anywhere along your arm or hand, while a low back injury can cause numbness or tingling down the back of your leg)
•     Pressure on the nerves of the spine, such as from a herniated disk
•     Pressure on peripheral nerves from enlarged blood vessels, tumors, scar tissue, or infection
•     Shingles or herpes zoster infection
•     Lack of blood supply to an area (for example, from atherosclerosis or frostbite)
•     Other medical conditions, including:
o     Carpal tunnel syndrome (pressure on a nerve at the wrist)
o     Diabetes
o     Migraines
o     Multiple sclerosis
o     Seizures
o     Stroke
o     Transient ischemic attack (TIA), sometimes called a "mini-stroke"
o     Underactive thyroid
o     Raynaud's phenomenon
•     Abnormal levels of calcium, potassium, or sodium in your body
•     A lack of vitamin B12 or other vitamin
•     Use of certain medications
•     Nerve damage due to lead, alcohol, or tobacco
•     Radiation therapy
•     Animal bites
•     Insect, tick, mite, and spider bites
•     Seafood toxins
Home Care
Your doctor should find and treat the cause of your numbness or tingling. Treating the condition may make the symptoms go away or stop them from getting worse. For example, if you have carpal tunnel syndrome or low back pain, your doctor may recommend certain exercises.
If you have diabetes, your doctor will discuss ways to control your blood sugar levels.
Low levels of vitamins will be treated with vitamin supplements.
Medications that cause numbness or tingling may need to be switched or changed. Do not change or stop taking any of your medicines or take large doses of any vitamins or supplements until you have talked with your doctor.
Because numbness can cause a decrease in feeling, you may be more likely to accidentally injure a numb hand or foot. Take care to protect the area from cuts, bumps, bruises, burns, or other injuries.

Dear patient, though your MRI findings are definately suggestive of a condition known as sub acute combined degeneration of spinal cord which is caused by vitamine B12 deficiency, the clinical response to the vitamin B12 supplimentation depends up on the duration of the symptoms. It has been found that if the symptoms are present for 6 months or more then the chances of compleate clinical recovery become very less with vitamin B12 supplimentation because what ever changes have occured in spinal cord or brain due to vitamin B12 deficiency had been present for a prolonged period of time and become resistent to resolve compleately after vitamin B12 supplimentation. However even then life long adminstration of monthly injections of vitamin B12 is requied to prevent the further damage to spinal cord and brain and to prevent further deteriotation of neurological symptoms . Although the disease is compleatly reversible in early stages with B12 supplimentation. there fore my sincere advise is not to omit vitamin B12 injections even if you feel disatified. However we can still try to rule out the other possibilities of of your symptoms by considering following common conditions like Diabetes mellitus, hypothyroidism, hypoparathyroidism, peripheral vascular disease , multiple sclerosis, chronic heavy metal poisoning like mercury and Drug intake like B blockers and flouroquinolones. just now you can get these investigations done to rule out some of these conditions, Blood sugar fasting, thyroid function test, serum sodium ,potassium and calcium and toxicology profile for heavy metals including mercury,lead and thalium