Most people with mild to moderate symptoms do not get worse. While many improve in the short term after surgery this improvement decreases somewhat with time. A number of factors present before surgery are able to predict the outcome after surgery, with people with depression, cardiovascular disease and scoliosis doing in general worse while those with more severe stenosis beforehand and better overall health doing better.

The natural evolution of disc disease and degeneration leads to stiffening of the intervertebral joint. This leads to osteophyte formation—a bony overgrowth about the joint. This process is called spondylosis, and is part of the normal aging of the spine. This has been seen in studies of normal and diseased spines. Degenerative changes begin to occur without symptoms as early as age 25–30 years. It is not uncommon for people to experience at least one severe case of low back pain by the age of 35 years. This can be expected to improve and become less prevalent as the individual develops osteophyte formation around the discs.

In the US workers' compensation system, once the threshold of two major spinal surgeries is reached, the vast majority of workers will never return to any form of gainful employment. Beyond two spinal surgeries, any more are likely to make the patient worse, not better.

Surgery may be useful in those with a herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. Discectomy has better outcomes at one year but not at four to ten years. The less invasive microdiscectomy has not been shown to result in a significantly different outcome than regular discectomy with respect to pain. It might however have less risk of infection.

The presence of cauda equina syndrome (in which there is incontinence, weakness and genital numbness) is considered a medical emergency requiring immediate attention and possibly surgical decompression. Regarding the role of surgery for failed medical therapy in people without a significant neurological deficit, a Cochrane review concluded that "limited evidence is now available to support some aspects of surgical practice".

Disc herniation can occur in any disc in the spine, but the two most common forms are lumbar disc herniation and cervical disc herniation. The former is the most common, causing lower back pain (lumbago) and often leg pain as well, in which case it is commonly referred to as sciatica. Lumbar disc herniation occurs 15 times more often than cervical (neck) disc herniation, and it is one of the most common causes of lower back pain. The cervical discs are affected 8% of the time and the upper-to-mid-back (thoracic) discs only 1–2% of the time.

The following locations have no discs and are therefore exempt from the risk of disc herniation: the upper two cervical intervertebral spaces, the sacrum, and the coccyx. Most disc herniations occur when a person is in their thirties or forties when the nucleus pulposus is still a gelatin-like substance. With age the nucleus pulposus changes ("dries out") and the risk of herniation is greatly reduced. After age 50 or 60, osteoarthritic degeneration (spondylosis) or spinal stenosis are more likely causes of low back pain or leg pain.

- 4.8% males and 2.5% females older than 35 experience sciatica during their lifetime.

- Of all individuals, 60% to 80% experience back pain during their lifetime.

- In 14%, pain lasts more than 2 weeks.

- Generally, males have a slightly higher incidence than females.

No set risk factors have been clearly defined for CES at this point in time. Individuals most at risk for disc herniation are the most likely to develop CES. Race has little influence with the notable exception that African Americans appear slightly less likely to develop CES than other groups; similarly, men are slightly more likely to develop CES than women. Middle age also appears to be a notable risk factor, as those populations are more likely to develop a herniated disc; heavy lifting can also be inferred as a risk factor for CES.

The most common forms are cervical spinal stenosis, which are at the level of the neck, and lumbar spinal stenosis, at the level of the lower back. Thoracic spinal stenosis, at the level of the mid-back, is much less common.

In lumbar stenosis, the spinal nerve roots in the lower back are compressed which can lead to symptoms of sciatica (tingling, weakness, or numbness that radiates from the low back and into the buttocks and legs).

Cervical spinal stenosis can be far more dangerous by compressing the spinal cord. Cervical canal stenosis may lead to myelopathy, a serious conditions causing symptoms including major body weakness and paralysis. Such severe spinal stenosis symptoms are virtually absent in lumbar stenosis, however, as the spinal cord terminates at the top end of the adult lumbar spine, with only nerve roots (cauda equina) continuing further down. Cervical spinal stenosis is a condition involving narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital or traumatic. Treatment frequently is surgical.

Spinal stenosis is an abnormal narrowing of the spinal canal or neural foramen that results in pressure on the spinal cord or nerve roots. Symptoms may include pain, numbness, or weakness in the arms or legs. Symptoms are typically gradual in onset and improve with bending forwards. Severe symptoms may include loss of bladder control, loss of bowel control, or sexual dysfunction.

Causes may include osteoarthritis, rheumatoid arthritis, spinal tumors, trauma, Paget's disease of the bone, scoliosis, spondylolisthesis, and the genetic condition achondroplasia. It can be classified by the part of the spine affected into cervical, thoracic, and lumbar stenosis. Lumbar stenosis is the most common followed by cervical stenosis. Diagnosis is generally based on symptoms and medical imaging.

Treatment may involve medications, bracing, or surgery. Medications may include NSAIDs, acetaminophen, or steroid injections. Stretching and strengthening exercises may also be useful. Limiting certain activities may be recommended. Surgery is typically only done if other treatments are not affected, with the usual procedure being a decompressive laminectomy.

Spinal stenosis occurs in as many as 8% of people. It occurs most commonly in people over the age of 50. Males and females are affected equally commonly. The first modern description of the condition is from 1803 by Antoine Portal. Evidence of the condition, however, dates back to Ancient Egypt.

Direct trauma can also cause cauda equina syndrome. Most common causes include iatrogenic lumbar punctures, burst fractures resulting in posterior migration of fragments of the vertebral body, severe disc herniations, spinal anaesthesia involving trauma from catheters and high local anaesthetic concentrations around the cauda equina, penetrating trauma such as knife wounds or ballistic trauma.

Cervical spinal stenosis is a bone disease involving the narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital. Treatment is frequently surgical.

Cervical spinal stenosis is one of the most common forms of spinal stenosis, along with lumbar spinal stenosis (which occurs at the level of the lower back instead of in the neck). Thoracic spinal stenosis, at the level of the mid-back, is much less common. Cervical spinal stenosis can be far more dangerous by compressing the spinal cord. Cervical canal stenosis may lead to serious symptoms such as major body weakness and paralysis. Such severe spinal stenosis symptoms are virtually absent in lumbar stenosis, however, as the spinal cord terminates at the top end of the adult lumbar spine, with only nerve roots (cauda equina) continuing further down. Cervical spinal stenosis is a condition involving narrowing of the spinal canal at the level of the neck. It is frequently due to chronic degeneration, but may also be congenital or traumatic. Treatment frequently is surgical.

Lumbar spinal stenosis (LSS) is a medical condition in which the spinal canal narrows and compresses the nerves at the level of the lumbar vertebrae. This is usually due to the common occurrence of spinal degeneration that occurs with aging. It can also sometimes be caused by spinal disc herniation, osteoporosis, a tumor, or trauma. In the cervical (neck) and lumbar (low back) region it can be a congenital condition to varying degrees.

It is also a common symptom for those who suffer from various skeletal dysplasias such as with pseudoachondroplasia and achondroplasia at an early age.

Spinal stenosis may affect the cervical or thoracic region in which case it is known as cervical spinal stenosis or thoracic spinal stenosis. In some cases, it may be present in all three places in the same patient. Lumbar spinal stenosis can cause low back pain, abnormal sensations, and the absence of sensation (numbness) in the legs, thighs, feet or buttocks, or loss of bladder and bowel control.

There are many recognized spinal diseases, some more common than others. Spinal disease also includes cervical spine diseases, which are diseases in the vertebrae of the neck. A lot of flexibility exists within the cervical spine and because of that, it is common for an individual to damage that area, especially over a long period of time. Some of the common cervical spine diseases include degenerative disc disease, cervical stenosis, and cervical disc herniation. Degenerative disc disease occurs over time when the discs within each vertebra in the neck begin to fall apart and begin to disintegrate. Because each vertebra can cause pain in different areas of the body, the pain from the disease can be sensed in the back, leg, neck area, or even the arms. When the spinal canal begins to lose its gap and gets thinner, it can cause pain in the neck, which can also cause a numb feeling in the arms and hands. Those are symptoms of cervical stenosis disease. The discs between each vertebra have fibers that can begin to deteriorate, and this can occur in cervical disc herniation. This disease is less common in younger people as it is usually a function of aging.

Potential non-surgical treatments include:

- Education about the course of the condition and how to relieve symptoms

- Medicines to relieve pain and inflammation, such as acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs)

- Exercise, to maintain or achieve overall good health, aerobic exercise, such as riding a stationary bicycle, which allows for a forward lean, walking, or swimming can relieve symptoms

- Weight loss, to relieve symptoms and slow progression of the stenosis

- Physical therapy, to provide education, instruction, and support for self-care; physical therapy instructs on stretching and strength exercises that may lead to a decrease in pain and other symptoms

Spinal disease (also known as a dorsopathy) refers to a condition impairing the backbone. These include various diseases of the back or spine ("dorso-"), such as kyphosis. Dorsalgia refers to those conditions causing back pain.

An example is scoliosis. Some other spinal diseases include Spinal Muscular Atrophy, Ankylosing Spondylitis, Lumbar Spinal Stenosis, Spina Bifida, Spinal tumors, Osteoporosis and Cauda Equina Syndrome.

Spondylosis is caused from years of constant abnormal pressure, from joint subluxation, sports, or poor posture, being placed on the vertebrae, and the discs between them. The abnormal stress causes the body to form new bone in order to compensate for the new weight distribution. This abnormal weight bearing from bone displacement will cause spondylosis to occur. Poor postures and loss of the normal spinal curves can lead to spondylosis as well. Spondylosis can affect a person at any age; however, older people are more susceptible.

Tethered spinal cord can be caused by various conditions but the main cause is when tissue attachments limit the movement of the spinal cord in the spinal column which causes abnormal stretching of the cord. The tethered spinal cord syndrome is correlated with having the causes:

- Spina bifida

- Occulta

- Mylomeningocele

- Meningocele

- History of spinal trauma

- History of spinal surgery

- Tumor(s) in the spinal column

- Thickened and/or tight filum terminale

- Lipoma(s) in the spinal column

- Dermal Sinus Tract (congenital deformity)

- Diastematomyelia (split spinal cord)

Tethered spinal cord is a disorder and not a mechanism so it does not spread to other people and there are no measures that can be done to prevent it beforehand. The only preventative measure that is successful is to surgically untether the spinal cord though there might already be irreversible damage.

Because neurological deficits are generally irreversible, early surgery is recommended when symptoms begin to worsen. In children, early surgery is recommended to prevent further neurological deterioration, including but not limited to chronic urinary incontinence.

In adults, surgery to detether (free) the spinal cord can reduce the size and further development of cysts in the cord and may restore some function or alleviate other symptoms. Although detethering is the common surgical approach to TCS, another surgical option for adults is a spine-shortening vertebral osteotomy. A vertebral osteotomy aims to indirectly relieve the excess tension on the spinal cord by removing a portion of the spine, shortening it. This procedure offers a unique benefit in that the spinal cord remains fixated to the spine, preventing retethering and spinal cord injury as possible surgical complications. However, its complexity and limited “track record” presently keeps vertebral osteotomies reserved as an option for patients who have failed in preventing retethering after detethering procedure(s).

Other treatment is symptomatic and supportive. Medications such as NSAIDs, opiates, synthetic opiates, COX-2 inhibitors, and off-label applications of tricyclic antidepressants combined with anti-seizure compounds have yet to prove they are of value in treatment of this affliction's pain manifestations. There is anecdotal evidence that TENS units may benefit some patients.

Treatment may be needed in adults who, while previously asymptomatic, begin to experience pain, lower back degeneration, scoliosis, neck and upper back problems and bladder control issues. Surgery on adults with minimal symptoms is somewhat controversial. For example, a website from the Columbia University Department of Neurosurgery says, "For the child that has reached adult height with minimal if any symptoms, some neurosurgeons would advocate careful observation only." However, surgery for those who have worsening symptoms is less controversial. If the only abnormality is a thickened, shortened filum, then a limited lumbosacral laminectomy with division of the filum may be sufficient to relieve the symptoms.

This syndrome was first noticed in the late 19th century. While information has been available for years, little widespread blind research has been done. More research has been called for, and doctors have conducted many studies with good results. There is a low morbidity rate, and no complications have been documented other than those typical of any type of back surgery. The association of this condition with others has been noticed, and needs further research to understand such relationships. TCS is causally linked to Chiari malformation and any affirmative diagnosis of TCS must be followed by screening for Chiari's several degrees. TCS may also be related to Ehlers-Danlos syndrome, or Klippel-Feil syndrome, which should also be screened for upon a positive TCS diagnosis. Spinal compression and the resulting relief is a known issue with this disorder. Like with the early-onset form, this disease form is linked to the Arnold-Chiari malformation, in which the brain is pulled or lowers into the top of the spine.

A severe but rare complication of this disease is vertebrobasilar insufficiency. This is a result of the vertebral artery becoming occluded as it passes up in the transverse foramen. The spinal joints become stiff in cervical spondylosis. Thus the chondrocytes which maintain the disc become deprived of nutrition and die. The weakened disc bulges and grows out as a result of incoming osteophytes.

Most often the radiculopathy found in the patients are located in the cervical spine, most commonly affecting C6-C8 spinal nerves.

Certain injuries can also lead to radiculopathy. These injuries include lifting heavy objects improperly or suffering from a minor trauma such as a car accident. Less common causes of radiculopathy include injury caused by tumor (which can compress nerve roots locally) and diabetes (which can effectively cause ischemia or lack of blood flow to nerves).

Wobbler disease is a catchall term referring to several possible malformations of the cervical vertebrae that cause an unsteady (wobbly) gait and weakness in dogs and horses. A number of different conditions of the cervical (neck) spinal column cause similar clinical signs. These conditions may include malformation of the vertebrae, intervertebral disc protrusion, and disease of the interspinal ligaments, ligamenta flava, and articular facets of the vertebrae. Wobbler disease is also known as cervical vertebral instability, cervical spondylomyelopathy (CSM), and cervical vertebral malformation (CVM). In dogs, the disease is most common in large breeds, especially Great Danes and Doberman Pinschers. In horses, it is not linked to a particular breed, though it is most often seen in tall, race-bred horses of Thoroughbred or Standardbred ancestry. It is most likely inherited to at least some extent in dogs and horses.

Diastematomyelia (occasionally diastomyelia) is a congenital disorder in which a part of the spinal cord is split, usually at the level of the upper lumbar vertebra.

Diastematomyelia is a rare congenital anomaly that results in the "splitting" of the spinal cord in a longitudinal (sagittal) direction. Females are affected much more commonly than males. This condition occurs in the presence of an osseous (bone), cartilaginous or fibrous septum in the central portion of the spinal canal which then produces a complete or incomplete sagittal division of the spinal cord into two hemicords. When the split does not reunite distally to the spur, the condition is referred to as a diplomyelia, or true duplication of the spinal cord.

The term, degenerative disc disease is a slight misnomer because it is not technically a disease, nor is it strictly degenerative. It is not considered a disease because degenerative changes in the spine are natural and common in the general population.

There is a disc between each of the vertebrae in the spine. A healthy, well-hydrated disc will contain a great deal of water in its center, known as the nucleus pulposus, which provides cushioning and flexibility for the spine. Much of the mechanical stress that is caused by everyday movements is transferred to the discs within the spine and the water content within them allows them to effectively absorb the shock. At birth, a typical human nucleus pulposus will contain about 80% water. However natural daily stresses and minor injuries can cause these discs to gradually lose water as the anulus fibrosus, or the rigid outer shell of a disc, weakens.

This water loss makes the discs less flexible and results in the gradual collapse and narrowing of the gap in the spinal column. As the space between vertebrae gets smaller, extra pressure can be placed on the discs causing tiny cracks or tears to appear in the anulus. If enough pressure is exerted, it's possible for the nucleus pulposus material to seep out through the tears in the anulus and can cause what is known as a herniated disc.

As the two vertebrae above and below the affected disc begin to collapse upon each other, the facet joints at the back of the spine are forced to shift which can affect their function.

Additionally, the body can react to the closing gap between vertebrae by creating bone spurs around the disc space in an attempt to stop excess motion. This can cause issues if the bone spurs start to grow into the spinal canal and put pressure on the spinal cord and surrounding nerve roots as it can cause pain and affect nerve function. This condition is called spinal stenosis.

For women, there is good evidence that menopause and related estrogen-loss are associated with lumbar disc degeneration, usually occurring during the first 15 years of the climacteric. The potential role of sex hormones in the etiology of degenerative skeletal disorders is being discussed for both genders.

Degenerative disc disease can also occur in other mammals besides humans; it is a common problem in several dog variants and attempts to remove this disease from dog populations have lead to several crosses, such as the Chiweenie.

Anterolisthesis location includes which vertebrae are involved, and may also specify which parts of the vertebrae are affected.

"Isthmic" anterolisthesis is where there is a defect in the pars interarticularis. It is the most common form of spondylolisthesis; also called spondylolytic spondylolisthesis, it occurs with a reported prevalence of 5–7 percent in the US population. A slip or fracture of the intravertebral joint is usually acquired between the ages of 6 and 16 years, but remains unnoticed until adulthood. Roughly 90 percent of these isthmic slips are low-grade (less than 50 percent slip) and 10 percent are high-grade (greater than 50 percent slip). It is divided into three subtypes:

- A: pars fatigue fracture

- B: pars elongation due to multiple healed stress effects

- C: pars acute fracture

Scoliosis affects 2–3% of the United States population, which is equivalent to about 5 to 9 million cases. A scoliosis spinal column's curve of 10° or less affects 1.5% to 3% of individuals. The age of onset is usually between 10 years and 15 years (can occur at a younger age) in children and adolescents, making up to 85% of those diagnosed. This is seen to be due to rapid growth spurts occurring at puberty when spinal development is most relenting to genetic and environmental influences. Because female adolescents undergo growth spurts before postural musculoskeletal maturity, scoliosis is more prevalent among females. Although fewer cases are present today using Cobb angle analysis for diagnosis, scoliosis remains a prevailing condition, appearing in otherwise healthy children. Incidence of idiopathic scoliosis (IS) stops after puberty when skeletal maturity is reached, however, further curvature may proceed during late adulthood due to vertebral osteoporosis and weakened musculature.

Radiculopathy is a mechanical compression of a nerve root usually at the exit foramen or lateral recess. It may be secondary to degenerative disc disease, osteoarthritis, facet joint degeneration/hypertrophy, ligamentous hypertrophy, spondylolisthesis, or a combination of these factors. Rarer causes of radiculopathy may include radiation, diabetes mellitus, neoplastic disease, or any meningeal-based disease process. Second-stage Lyme meningitis resembles aseptic meningitis and is often associated with radiculopathies.

There are many causes of scoliosis, including spinal deformities, neuromuscular problems, and inherited diseases or conditions caused by the environment.

An estimated 65% of scoliosis cases are idiopathic, about 15% are congenital and about 10% are secondary to a neuromuscular disease.

Idiopathic scoliosis represents a majority of cases, but its causes are largely unknown. Results of recent studies indicate potential heritability of the disorder. About 38% of variance in scoliosis risk is due to genetic factors, and 62% is due to the environment. The genetics are likely complex however, given the inconsistent inheritance and discordance among monozygotic twins. The specific genes that contribute to development of scoliosis have not been conclusively identified. At least one gene, "CHD7", has been associated with the idiopathic form of scoliosis.

Several candidate gene studies have found associations between idiopathic scoliosis and genes mediating bone formation, bone metabolism, and connective tissue structure. Several genome-wide studies have identified a number of loci as significantly linked to idiopathic scoliosis. In 2006 idiopathic scoliosis was linked with three microsatellite polymorphisms in the MATN1 gene (encoding for "Matrilin 1, cartilage matrix protein"). Fifty-three single nucleotide polymorphism markers in the DNA that are significantly associated with adolescent idiopathic scoliosis were identified through a genome-wide association study.

Adolescent idiopathic scoliosis (AIS) has no clear causal agent, and is generally believed to be multifactorial. The prevalence of scoliosis is 1% to 2% among adolescents, however the likelihood of progression among adolescents with a Cobb angle of less than 20° is about 10% to 20%.

Congenital scoliosis can be attributed to a malformation of the spine during weeks three to six "in utero" due to a failure of formation, a failure of segmentation, or a combination of stimuli. Incomplete and abnormal segmentation results in an abnormally shaped vertebra, at times fused to a normal vertebra or unilaterally fused vertebrae, leading to the abnormal lateral curvature of the spine.

The risk of serious complications from spinal fusion surgery for kyphosis is estimated to be 5%, similar to the risks of surgery for scoliosis. Possible complications include inflammation of the soft tissue or deep inflammatory processes, breathing impairments, bleeding, and nerve injuries. According to the latest evidence, the actual rate of complications may be substantially higher. Even among those who do not suffer from serious complications, 5% of patients require reoperation within five years of the procedure, and in general it is not yet clear what one would expect from spine surgery during the long-term. Taking into account that signs and symptoms of spinal deformity cannot be changed by surgical intervention, surgery remains to be a cosmetic indication. Unfortunately, the cosmetic effects of surgery are not necessarily stable.