Nerve Pain & Neuropathy

All nerves that exit from the spinal cord comprise the Peripheral Nervous System. These nerves descend following specified paths whereby there are areas of anatomic narrowing, as between two muscles or beneath a tight band of fascia. If a nerve gets compressed in any of these areas of tightness for an extended period of time, the nerve will become inflamed. This leads to symptoms of pain, tingling and numbness below the area where the compression exists. When severe compression exists, the nerve injury leads to a loss of sensation or muscle weakness. Left untreated, the nerve damage can become permanent.

Examples of nerve compression are:

1. The sprained ankle where suddenly pain appears over the outside of the leg with pains and needle sensation running down the leg

2. The high heeled shoe wearer who experiences numbness to their large toe

3. The person who sits cross legged and experiences weakness in the leg when standing or walking

4. The person following knee replacement surgery discovers burning and tingling below the knee

5. Following the surgical repair of ankle fractures – the nerve may be damaged from direct trauma on the incision exposure

The Common Peroneal Nerve begins as the Sciatic nerve from the spine and winds its way to behind the knee. There it enters a tunnel on the outside of the knee, just below the head of the Fibula (“funny bone of the leg”). Here the nerve passes in an anatomic tunnel formed by the Peroneal muscles and Fascia. This nerve innervates the outside of the lower leg and also the top of the foot.

Compression of the Peroneal Nerve produces sensory symptoms like numbness or burning pain from the top of the foot to the knee. Muscular symptoms of this compression produce a drop foot with the leg and foot unable to walk on. Some experience Restless Leg syndrome while others describe unbearable pain in the leg or ankle.

Compression of this nerve is commonly seen in Diabetics or those with Neuropathy. Sports injuries like ankle sprains; broken ankles or knee sprains commonly seen in soccer, basketball, football, lacrosse, baseball, field hockey place patients at great risk for this injury.

Deep Peroneal Nerve Compression

Other branches of the Common Peroneal Nerve are exposed to compression on the top of the foot where a small tendon crosses over a smaller branch of the nerve and compresses it against the underlying bone. The injury produces strictly sensory pain like a knife sticking into the top of the foot. Pain may travel to the first and second toes. This compression occurs from too tightly tied laces, tight shoes, and direct trauma to the top of the foot producing a crush injury; a broken bone and arthritis.

Superficial Peroneal Nerve Compression

The least common area injury is in the lower outer leg where the Superficial Peroneal Nerve may be compressed. Symptoms are a burning to the area over the outer ankle and pain. Fairly common causes of injury to this nerve are traction injuries from a sprain, direct trauma from ankle fracture surgery, high-top boots, and cast immobilization.

Non-surgical treatment of nerve compression may require a change in lifestyle or a decrease in repetitive activities that the patient may be involved with, in order to allow the nerve to recover and return to normal. Success is measured to the length of time prior to diagnosis and initiation of treatment. Surgical treatment of nerve compression primarily involves the release of those tissues (ligament, tendon or fibrous bands) that create the tightness to the tunnels that the nerve travels through. Once a nerve is not bound, proper blood flow occurs allowing the nerve to heal itself. Proper gliding over joints with movement is also increased.

The Tarsal Tunnel is a region located on the inside portion of the ankle formed by a thickened tissue called the flexor retinaculum which encloses the contents of the tunnels artery, nerve and veins. Tarsal Tunnel Syndrome is the compression of this tunnel. Today we identify this syndrome by its Four Sites of Compression:

1. The Tarsal Tunnel
2. The Calcaneal Tunnel
3. The Medial Plantar Tunnel
4. The Lateral Plantar Tunnel

Compression of this tunnel is not unlike Carpal Tunnel Syndrome where sensory loss or pain occurs. Loss of sensation to the bottom of the foot is a hallmark of this condition. The lack of sensation to the foot’s surface results in imbalance, gait alterations, ulcerations, infections and loss of limb. Common causes of Tarsal Tunnel Syndrome are diabetes, trauma (sprains, fractures), enlarging masses in the tunnel (Lipomas, tumors, extra muscle tissue) alcoholism and gait abnormalities (pronation-flat feet).

Conservative treatment exists for this condition. When failure of conservative treatment is evident, surgical intervention is warranted.

Morton’s Neuroma is another type of peripheral nerve problem in the foot caused by repetitive compression of the common plantar digital nerve. This nerve lies between the heads of the metatarsal bones. The neuroma that develops is not a true neuroma but rather a chronic nerve compression. The nerve actually thickens and becomes bulbous. High heels and tight shoes can increase this type of pain. Patients usually complain of tingling or burning or numbness in the ball of the foot. The third and fourth toes are most often affected. A feeling of a ball or mass on the bottom of the forefoot is not uncommon. Multiple neuromas are possible in the same foot.

Diagnosis and Testing

Following a podiatric neurologic examination two options to clinically determine if a neuroma diagnosis is correct are available:

Ultrasound and PSSD testing

At North Jersey Podiatry we offer the latest in Ultrasound technology to view the soft tissue detail of your foot, similar to an MRI. Additionally the use of PSSD (pressure specified sensory device) to measure the function of your nerves is performed. This test is non-painful and non- invasive that quantifies the sensory loss of the nerve. This test will verify the patient doesn’t have problems with other nerves and the Morton’s Neuroma is an isolated problem. The PSSD can also help identify those individuals who have been misdiagnosed as having a Morton’s Neuroma and actually have a mild early Neuropathy.

At North Jersey Podiatry non-surgical treatment consists of identifying the predisposing factors that created the neuroma. The use of lower heeled, wide toe shoes may be helpful. The correction of flat footed (overly pronated) feet by using custom made Orthotics is beneficial. Shockwave treatment (EPWT treatment) has been successfully utilized to relieve patients of their pain and discomfort. Since the advent of this procedure open surgical correction for this condition has decreased. The importance of proper placement of a corticosteroid injection via ultrasound guidance has allowed for decreased open surgical reduction seen in the past ten years.

At North Jersey Podiatry our treatment is performed on an outpatient basis usually about one hour in length. Under appropriate anesthesia Dr. Klein finds the nerve and releases the areas of compression – the deep transverse intertarsal ligament. Intrinsic fibrosis or scarring is released and the epineurium is opened. THE NERVE IS NOT CUT OUT.

Why do we not cut out the nerve?

When a nerve is cut, the piece of nerve that is beyond the cut point eventually dies, however, its Schwann cells that encircle the nerve fibers remain for a longer time. These cells secrete a chemical messenger known as nerve growth factor that instructs the cut end of nerve to grow back. Unfortunately, multiple nerve sprouts grow in a disorderly array in multiple directions forming a knot of nerve fibers. This leads to the formation of a TRUE NEUROMA. If this forms in an area of pressure, it will become very painful.

Recurrent Neuromas or Prior Nerve Excision

Once a nerve is cut and removed the natural physiologic process is for the nerve to grow. If growth occurs and is painful then excision of this nerve portion is required with placement of the new stump implanted into a muscle via a RPNI (Regenerative Peripheral Nerve Interface) or bone using microsurgical techniques. When the bottom of the foot is affected the nerve end is buried deep into a muscle in the non-weight bearing portion of the arch where it will not be subject to weight or compression.

Risk Involved with Morton’s Neuroma Surgery

The biggest risk associated with this operation is that the patient may still be left with areas of pain or there is no change in the amount of pain. Common risks associated with any type of surgical procedure include bleeding, infection and scaring. Other risks include an increase in pain (which is usually the progression of the neuropathy not an operative complication) or Deep Vein Thrombosis which are uncommon.

When a nerve gets injured due to traumatic injury or surgery the damaged portion of the nerve, the neruoma, produces shooting, stabbing and/or throbbing pain.

Surgery is an option once it is determined that the pain is from a damaged/injured nerve and you are a good candidate for surgery. Dr. Klein will use nerve block to determine which nerve is causing the pain. This is performed in the office using local anesthetics similar to what a dentist would use in dental work. The nerve block should last several hours to see how the involved area will feel after surgery. Several hours later the pain will return that existed prior to the nerve block. This is a confirmatory exam to evaluate the appropriate response to what surgery may be able to do.

Nerve surgery is performed as an outpatient procedure taking about an hour. Appropriate anesthesia is administered by an Anesthesiologist. Using microsurgical techniques, Dr. Paul Klein finds the damaged area of the nerve, and dependent upon the clinical findings can elect to perform a Neurolysis (release a compressed nerve) a Neurectomy (excision of nerve growth), a Nerve Transfer (add a healthy nerve to a damaged nerve or a Nerve Graft (replace damaged nerve with another nerve) cuts it out and buries or implants the healthy end into a muscle. A surgical dressing is applied at the end of surgery. Some patients notice an immediate difference in their pain in the recovery area and for others it may take months. Postoperative care is followed closely by Dr. Paul Klein. As in all nerve surgery, risks do exist. Risks are similar to neuroma excision with the added caveat that some patients continue to have pain and their body never responds to the removing of the nerve. These patients have “centralized pain” which means their pain doesn’t respond to the procedures on the nerve itself and instead these patients require the expertise of pain management specialist.

Patients should first consult their primary care doctor to determine if the cause of the pain is nerve related or a side effect of medication or a therapy. Also pain management specialist may be able to help diagnose and sometimes manage the pain especially for patient that are not good surgical candidates.