Herniated Disc

Herniated Disc Types

The cervical (neck), thoracic (mid back), and lumbar (lower back) regions of the spine contain discs, structures made of a thick band of fiber, surrounding a jelly-like middle. Disc herniations are created when the jelly-like middle of a disc protrudes through the fibrous surroundings. They come in three types depending on the region of the spine where the herniation occurred. The thoracic spine is mainly used for support and protection, whereas the cervical and lumbar spine are used for support and movement, making the latter pair more likely to experience disc related problems including herniations.

Cervical Herniation (Neck)

Discs between the 7 vertebrae of the cervical spine or neck are prone to herniations because of the flexibility and range of motion in that region. With time and increased motion, the fibrous outer portion of the disc, the annulus fibrosis, develops small tears and weak areas allowing the jelly-like inner portion of the disc, the nucleus pulposus, to extrude through. The herniation usually occurs to either the posterior (back) or lateral (side) sides of the body. A posterior herniation is more likely to be central and press on the spinal cord, a thick band of nerves that starts at the brain and moves through the spinal vertebrae. Lateral or side herniations tend to cause compression on spinal nerve roots, nerves exiting the spinal cord and branching into the body.

Thoracic Herniation (Mid Back)

The thoracic spine typically does not experience herniations because its primary functions are stabilization, support, and protection of the internal organs (i.e. not movement related). However, they do occur occasionally and can occur centrally, pressing on the spinal cord, or toward the side, pressing on nerve roots. Symptoms are occur based on which direction the disc herniates.

Lumbar Herniation (Lower Back)

The lumbar spine has a large range of motion, like the cervical spine, and also bears the majority of body weight. These conditions make lumbar discs more susceptible to herniations than discs in any other region of the spine. With added wear from weight bearing, aging, and repetitive motions, the fibrous outer portion of the disc, the annulus fibrosis, weakens or develops small tears that allow the inner jelly portion of the disc, the nucleus pulposus, to squeeze through and cause a herniated disc. Lumbar herniations can compress the spinal nerve roots, the spinal cord, or both.

Herniated Disc Causes

Discs in the cervical and lumbar regions of the spine are larger and more prone to injury than those in the thoracic region which has less flexibility and range of motion. Based on the individual’s spinal structure and motion, disc herniations are more likely to occur either towards the back, by the spinal cord, or towards the sides, by the nerve roots. Causes include aging, weight, trauma, and genetics.

Aging

As our bodies age, structures that contained a lot of water and moisture, such as the skin and the spinal discs, begin to dry. This dehydration process that occurs naturally with aging causes the discs to degenerate and shrink; it is the most common cause of disease in spinal discs. In addition, wear caused by movement can create tears in the outer annulus portion. The tears in the annulus make it easier for the inner nucleus pulposus to be released, creating a herniated disc.

Weight

Weight is another common cause of disc herniations because the spine, particularly the lumbar region, supports most of your body weight. As weight increases beyond a healthy level, the vertebral bodies struggle under the increased pressure and this is transferred to the discs. The pressure squeezes the discs, which results in the development of annulus tears and nucleus pulposus leaks. Weight and obesity can lead to recurring herniations at the same disc.

Trauma

Chronic trauma caused by repetitive motions and tasks often related to occupation, leisure, or sports can create wear on the disks. This is particularly common when the discs are subjected to repeated stress from tasks, such as physical labor jobs, that involve bending, lifting, and twisting of the lumbar spine. Wear increases with the amount of repetition and stress.

Acute trauma is any single occurrence event, such as an automobile accident, that places a large amount of stress on the spine. The large excess pressure placed on the spine causes the disc to herniate immediately instead of over time like it does with chronic trauma.

Genetics

Disc herniations are more likely with certain genetics; the likelihood of disc herniation or degeneration increases if other family members struggled with similar issues. The direct causation is still being researched but there is evidence to support a relationship between genetics and predisposition to disc herniations.

Herniated Disc Symptoms

Disc herniations range from causing no symptoms to causing severe and incapacitating symptoms. Symptoms are based on the spinal region, nerve proximity, and size of the herniation. They occur most commonly in the lumbar, cervical, thoracic spinal regions, in that order.

Cervical Herniation (Neck)

Spinal nerves that branch out of the cervical spine control function in the upper extremities (shoulders, arms, and hands). Therefore, a herniated disc in this region that compresses a nerve will produce symptoms in the upper extremity including a sharp shooting or throbbing pain, numbness or tingling, and decreased sensation. These typically occur unilaterally, only on one side of the body, and the specific location of the symptom will vary based on the nerve being compressed. For example, weakness in the deltoid muscle while raising your arms from your sides could indicate a disc herniation at the C4-5 level. Other potentially affected muscles include the bicep, triceps, wrist, and hand muscles.

C4-C5 Herniation: The C5 nerve root is responsible for the deltoid muscle which sits on top of the shoulder, outside of the upper arm. A herniation at the C4-5 level would cause shoulder pain and possibly weakness of the deltoid muscle.

C5-C6 Herniation: The C6 nerve root is responsible for the bicep and wrist extensor muscles. The bicep bends the elbow and the wrist extensors allow for pulling the wrist back to put the palm up. A disc herniation may cause weakness at one or both muscles groups with pain that may radiate down the thumb side of the arm.

C6-7 Herniation: The C7 nerve root is responsible for the triceps and flexors of the wrist. The triceps straighten the elbow and the wrist flexors bend the wrist to bring the hand closer to the forearm. A disc herniation may cause weakness at one or both muscle groups. Pain may radiate down the back of the arm and into the middle finger.

C7-T1 Herniation: The C8 nerve root is responsible for flexion of the fingers, such as with making a fist. A disc herniation may cause a weakened grip with pain that radiates into the pinky side of the arm.

Spinal Cord compression: If a disc herniation compresses the spinal cord, symptoms, called cervical myelopathy may exist, which consist of difficulty with fine motor movements, unsteadiness when walking, and/or changes with bladder habits, such as incontinence.

Other symptoms that may be related to a disc herniation in the neck are local symptoms of pain in the neck, stiffness in the neck, headaches, and decreased range of motion in the neck.

Thoracic Herniation (Mid Back)

Spinal nerves exiting from the thoracic spine are related to chest and abdominal functions (such as skin sensation, intercostal and abdominal muscles), except for the first thoracic nerve which also is responsible for some of the fingers. Therefore, a herniation at the thoracic level will produce symptoms of pain that radiate around the torso near a specific rib. These typically occur unilaterally, only affecting one side of the body. Common symptoms include sharp, shooting, stabbing, or electrical pain. The specific location of the symptom will vary based on the nerve being compressed.

T1-T2 Herniation: The T1 spinal nerve is responsible for the ring and pinky fingers and the area around the first rib. A herniation here may cause pain at the back or chest around the first rib, or pain in the ring and/or pinky fingers.

T2-T6 Herniation: The T2 through T6 spinal nerves are responsible for the muscles between each rib, intercostal muscles, and skin over the ribs. A disc herniation may cause pain in the back or chest at the corresponding rib.

T7-T12 Herniation: The T7 through T11 spinal nerves are responsible for the intercostal muscles of the corresponding rib, skin on the thorax, and the abdominal muscles. A disc herniation may cause pain in the back, chest, or abdomen.

T12-L1 Herniation: The T12 spinal nerves are responsible for the abdominal muscles and the skin over the buttocks. A disc herniation at this level may cause pain into the buttocks or over the abdomen.

Spinal Cord Compression: Compression at any level may cause symptoms of unsteady gait, weakness in the legs, or bladder changes, such as incontinence. In severe cases of compression on the spinal cord in the thoracic region of the spine may cause complete paralysis from the waist down.

Lumbar Herniation (Lower Back)

Spinal nerves that branch out of the lumbar spine control function in the lower extremities (buttocks, hips, legs, and feet). Therefore, a herniated disc causing nerve compression in this region will produce symptoms in the lower extremities including a sharp, shooting, burning, or electrical pain and potentially numbness or changes in sensation. For example, weakness at the knee while straightening the leg could indicate a disc herniation at the L3-4 level. Other potentially affected muscles include the quadriceps, tibialis anterior, and flexors of the foot. Symptoms may also include neurogenic claudication, a nerve-related pain that increases with walking and improves with rest. These typically occur unilaterally, only on one side of the body, and the specific location of the symptom will vary based on the nerve being compressed.

L1-L2 Herniation: The L1 spinal nerve root is responsible for the psoas muscle, which is found within the body cavity along the lumbar spine. Weakness in the psoas muscle and pain in the groin and front of the thigh may occur; the former can cause difficulty with lifting the leg, for example, while walking up stairs.

L2-L3 Herniation: The L2 nerve root is responsible for the iliopsoas muscles. A disc herniation at this level may cause weakness in an iliopsoas muscle, which may cause difficulty while walking up the stairs and/or pain that radiates into the front of the thigh.

L3-L4 Herniation: The L3 nerve root is responsible for the quadriceps femoris muscles, located on the front of the thigh and helps extend, or straighten, the knee. A disc herniation may cause weakness of quadriceps femoris, which may cause weakness while straightening the leg and/or pain in buttocks that radiates to the lower portion of the front of the thigh.

L4-L5 Herniation: The L4 nerve root is also responsible for the quadriceps femoris muscles and in some people is also responsible for the tibialis anterior muscle. The quadriceps femoris straightens the knee and the tibialis anterior brings the toes up while walking. A herniation may cause weakness while straightening the knee or lifting the toes when walking, which may lead to a foot drop. Pain may radiate from the buttock to the top of the back of the thigh and then to the front of the shin.

L5-S1 Herniation: The L5 nerve root is responsible for the tibialis anterior muscle in most people and foot and toe dorsiflexion. The tibilais anterior brings the toes up toward the face and foot and toe dorsiflexion brings the foot toward the face. Pain may radiate from the buttock, down the back of the thigh and calf, and into the foot, mainly on the inside of the foot.

S1 Herniation: The S1 nerve root exits below the S1 vertebral body, which is responsible for calf muscles, which allow for plantar flexion, or pressing down like on the gas pedal in the car. A disc herniation may cause weakness with plantar flexion which could cause difficulty or inability to stand on toes and pain that may radiate from the buttock down the back of the leg and into the bottom of the foot’s outside edge.

The main symptoms of lumbar disc herniation would radiate based on the location of the disc herniation. There are other symptoms such as localized lower back pain, decreased range of motion in the lumbar spine, and limping or difficulty walking. An emergent spinal condition found only in the lumbar spine is cauda equina syndrome. The spinal cord ends around the T12-L2 vertebral bodies in a collection of nerves called the cauda equina, which is like a horsetail. If a large disc herniation places pressure on the cauda equina, this produces a large amount of inflammation around these nerves and distinct symptoms which include saddle anesthesia (numbness in the perineal regions, the region that would make contact when sitting in a saddle), bowel and/or bladder incontinence, weakness in the legs, and unsteadiness with walking. This is a rare condition, but is serious and needs emergent attention to prevent irreversible damage to the nerves.

Herniated Disc Diagnosis

Patient history and physical examination are typically the first step in diagnosing disc herniations. Types of symptoms, duration of symptoms, factors that improve/exacerbate symptoms, treatments that have been already tried, and past relevant medical problems/surgeries are all collected during the history. The physician completes a physical exam to check for specific symptoms by inspecting the back, assessing gait, and testing the upper and lower extremities for motor strength, reflexes, and range of motion.

Both history and physical exam contribute to the diagnosis of a disc herniation, but imaging is necessary to finalize the diagnosis. X-rays are typically obtained first to look at the overall alignment of the spine and to check for spinal abnormalities such as scoliosis (curve in the spine), that may affect viable treatment options. These 2D results are supplemented with advanced imaging tests such as MRI or CT scans because these show a 3D view of the spine. MRI scans which show soft tissues, such as nerves and discs, are generally preferred over CT scans which show bony elements. Advanced imaging can show exactly which nerve or nerves are affected by a herniated disc and the size of the disc herniation. Together history, physical exam, and imaging are all necessary in order to make a correct diagnosis and design an optimal treatment plan for a disc herniation.

Dermatomes are areas of the skin and musculature that a single nerve supplies motor and sensory function to. Based on the location and type of symptom (e.g. radiating or shooting pain, numbness, tingling, or loss of muscle strength) knowledge of dermatomes can help identify which spinal nerve may be affected by disc herniations. However, each person is anatomically unique so this is used more as a guide than as a definite diagnostic technique.

Cervical Herniation (Neck)

Physical exam results that imply a cervical disc herniation include decreased range of motion in the neck with difficulty moving the chin toward the chest, leaning the head back, or turning left and right as if checking a blind spot while driving. Motor strength testing would be performed on both the upper and lower extremities because weakness in certain muscle groups could imply a disc herniation at the cervical level where the relevant nerve branches off of the spinal cord. For example, weakness in the deltoid muscle while raising your arms from your sides could indicate a disc herniation at the C4-5 level. Increases or decreases in the bicep, brachioradialis, or tricep muscle reflexes are commonly used to test for spinal disc herniation and can potentially identify the affected spinal level because they are connected to the C5, C6, and C7 nerve roots respectively. Other tests include checking for changes in sensation and a heel to toe walk to evaluate balance.

Thoracic Herniation (Mid Back)

Physical exams checking for a thoracic disc herniation will be much less involved than those looking for cervical and lumbar disc herniations. The exam typically begins with examining the back for an abnormal curve, uneven muscles, or skin changes such as bruising. After inspection, the doctor will perform palpations over the muscles and center of the back. The legs would be tested for motor strength to ensure that both legs are at full strength and functioning normally. Lastly the physician may check for changes in sensation from one side of the body to the other.

Lumbar Herniation (Lower Back)

Physical exam abnormalities for the lumbar spine tend to occur exclusively in the lower body. As with evaluating the cervical and thoracic spine, it is important to start by looking at the back for changes in the skin, decreases in muscle size, or unevenness from one side of the back to the other. The next step would be palpation of the muscles and center of the back. Lumbar spine range of motion is tested with flexion, such as touching toes, and extension, leaning back at the waist to look for decreased motion due to pain. Motor strength testing would be performed on the lower extremities because weakness in certain muscle groups could imply a disc herniation at the lumbar level where the relevant nerve branches from the spinal cord. For example, a disc herniation at L3-4 or L4-5 levels may cause weakness with knee extension or straightening the leg. Changes in sensation may also be tested throughout the leg to check for areas with decreased sensation throughout or relative to the opposite leg. Increases or decreases in the patellar and Achilles reflexes are commonly used to test for spinal disc herniation and can potentially identify the affected spinal level because they are connected to the L3/L4 and S1 nerve roots respectively. Other exam results that imply lumbar disc herniations are abnormal walking patterns, including inability to walk on the heels and the toes.

Herniated Disc Treatment

Once a disc herniation is diagnosed through history, physical exam, and imaging studies, a treatment plan is created. Treatment generally begins with addressing symptoms through conservative, non-invasive options and may include a combination of options. These options include alternative therapy, medication, physical therapy, injections, and lifestyle modifications.

Traditional surgical options to perform a discectomy used large incisions and left a great amount of tissue and muscle disruption. These procedures are still used in certain patients, but there are several minimally invasive surgical options that may be more appropriate for addressing a disc herniation. Minimally invasive surgeries are performed through a small incision and without cutting muscle tissue to allow for faster healing and return to normal activities post-operation. The best surgical procedure will be determined by the location of the disc herniation, size of the disc herniation, wear on the disc, and alignment concerns, such as a vertebral slips or abnormal curvature.

Conservative Options

Lifestyle Modification

Certain lifestyle factors may increase the incidence of a herniated disc such as smoking and increased weight. Smoking decreases blood flow throughout the body which is needed to repair damaged tissues, including those around a herniated disc. Cessation may restore blood flow, allowing the tissues to access proper nutrition. Added weight may increase the risk for single-occurrence or recurring disc herniation because extra stress is placed on the disc, making it easier to tear. Reducing weight through a low-calorie diet and exercise can reduce pressure on the spine, decreasing the symptoms of a disc herniation.

Repetitive leisure or work-related motions such as excessive bending, lifting, and twisting, along with any activity that may be high impact on the spine, such as running or riding ATVs, can also lead to disc herniations. Some of these repetitive task activities may be due to leisure and others due to demands of a job. For people with full labor or heavy-duty jobs, you may need to change jobs or support your work with proper lifting technique, relaxed breaks, and equipment such as a back brace to avoid worsening symptoms. You may also need to alter or avoid high impact activities, such as running to reduce the symptoms of a disc herniation.

Alternative Therapy

Alternative therapies include massages, chiropractic care, and acupuncture. These may also be referred to as manual therapies since they address the spine with hands on technique. Massage relieves tension in muscles surrounding the spine and in arm and leg muscles experiencing radiating symptoms. These muscles may be under tension due abnormalities with walking and changes in posture due to pain from disc herniation. Chiropractic care may use specific techniques, such as adjusting the spine or application of traction on the spine. Acupuncture may also provide pain relief as muscles are stimulated electrically.

Physical Therapy/Exercise

Physical therapy focuses on changing body mechanics to improve posture and walking as well as to strengthen and retrain muscles, particularly those in the core. The initial step is meeting with a Physical Therapist for a consultation to assess posture, gait, and muscle weakness and to design a personalized exercise program. Other techniques that physical therapists may use are manual treatments such as massage, ultrasound, and electro-stimulation through a TENS (transcutaneous electrical nerve stimulation) unit. A combination of these methods can provide symptom relief.

A home exercise program may be used in conjunction with or instead of a formal physical therapy regimen. A daily low impact exercise regimen is important for strengthening muscles, especially those in the core. Low impact cardiovascular activities such as walking, swimming, elliptical, and biking are also important for increasing blood flow and strengthening muscles without adding stress on the spine. Home exercise can also lead to weight loss which may reduce pressure on the spine and reduce symptoms. Home exercise routines should be paired with stretches and physician supervision to avoid harm.

Medications

There are multiple types of prescribed and over the counter medications that may be used to treat the symptoms of disc herniation. Some of these medications include Tylenol (acetaminophen), NSAIDs (nonsteroidal anti-inflammatory drugs), muscle relaxants, nerve membrane stabilizers, topical medications, and off label medications.

Common over the counter medications are acetaminophen and NSAIDs. Acetaminophen is considered an analgesic, meaning it relieves pain but does not reduce inflammation. NSAIDs are effective at both relieving pain and reducing inflammation; they can be found in brand and generic forms over the counter. These medications are best taken with food to avoid an upset stomach. They can be taken for longer durations, as long as there is no history of kidney disease. The mechanism of both NSAIDs and Acetaminophen differ, so they are taken together often to combat pain.

Muscle relaxants are used to provide relief from muscle spasms and increase range of motion; they are best used in combination with physical therapy or an exercise/stretching regimen. Drowsiness is a common side effect of muscle relaxants and they are not recommended while driving or working. Common muscle relaxants include Flexeril, Soma, Baclofen, Robaxin, and Tizanidine.

Nerve membrane stabilizers are another class of medications often used to treat the numbness, tingling, shooting, stabbing, or radiating pain associated with disc herniation. Gabapentin (Neurontin) and Lyrica (Pregabalin) are commonly prescribed nerve membrane stabilizers and work by reducing pain signals released by nerves. Both medications, Gabapentin especially, can be taken in higher dosages multiple times per day, but this class of medication may cause dizziness and drowsiness. Nerve membrane stabilizers are typically started on a low and infrequent dose; the dosage is gradually increased until the pain is controlled and then gradually decreased prior to discontinuation.

There are other medications that may be used ‘off-label,’ meaning not for the use listed on the label. Some common medications used off label for pain are anti-depressants, such as Cymbalta and Amitriptyline. Similar to the nerve membrane stabilizers, these medications are slowly increased in dosage and they also target nerve-type pain, such as burning, numbness, and tingling associated with nerve pain. They may also cause drowsiness and are usually used at night for pain control.

Epidural Steroid Injections

Epidural steroid injections reduce pain by injecting steroid, or anti-inflammatory, medication at a specific level/levels in the spine. As the herniation places pressure on a nerve, this causes inflammation of the nerve and surrounding tissue which causes pain. A specialized needle is used to deliver medication to the correct area, past the muscles of the back and as close to the spinal nerves as possible. As steroids are a natural anti-inflammatory, this may reduce the inflammation around the nerve, diminishing pain caused by the disc herniation. Steroid injections have the ability to provide pain relief for up to several months, and provide better pain relief for radiating symptoms, such as leg pain, than treatments designed for back pain alone. Steroid injections are only safe to have completed 3 times in one year and must be at least one month apart between sequential injections. This is due to the muscle and tendon breakdown with exposure to the steroid medication too often or too soon.

Surgical Options

Cervical

A foraminotomy is a minimally invasive surgical decompression procedure that is typically performed on the cervical spine to alleviate compression on a cervical spinal nerve from a disc herniation. This procedure is performed through a small midline incision on the back of the neck. A small amount of bone from the back of the vertebrae, called the laminae, is removed so that the foramen, an opening for the spinal nerve is reached. The disc material is then clipped away to leave the nerve decompressed. The incision is closed and the procedure is completed.

Lumbar

A microdiscectomy is a minimally invasive surgical decompression procedure that is typically performed on both the thoracic and lumbar spine to address disc herniations. A small incision is made in the midline of the back until the joint of the spine, the facet, is reached. A small portion of the joint is removed to visualize the spinal nerve and disc herniation. The disc herniation is removed and once the nerve is free of compression, the incision is closed.

Endoscopic discectomy is a minimally invasive surgical decompression surgery that uses specialized instrumentation in order to perform the disc removal. A small incision is made on the midline of the back and a specialized imaging tool, called a fluoroscope is used to confirm that the correct vertebral level has been targeted for the procedure. After the incision is made a thin wire, called the guide wire, threaded through until it hits bone. A series of small cylindrical tubes are then placed over the guide wire to open the incision. A specialized retractor, a light source, and surgical instruments are place down these tubes and the disc material is removed to alleviate pressure on the nerve root. Once this is completed, the retractor is readjusted to target the opposite side of the spine and more disc material is removed.

The procedures listed above are decompressive surgeries only, meaning that the herniated disc or tissues compressing the nerve are removed and no instrumentation is left in place. A stabilization procedure may be performed in combination with a discectomy. For example, in a case involving spondylolisthesis, a slipped vertebrae, a stabilization may be used to prevent worsening further mal-alignment. The benefit of these procedures includes less pain medication, lower chances of infection, less scarring, faster recovery, and same-day discharge.