Mortons Neuralgia Complete Treatment Guide

Mortons Neuralgia

Mortons Neuralgia is also know by it’s more common name of an interdigital neuroma or Morton’s neuroma. This is a very common disorder in that is more of a nuisance than a life threatening problem. Luckily it is very well researched and it is very treatable!

 

Mortons Neuralgia
Mortons Neuralgia

 

  • The Morton’s Neuralgia (aka Interdigital Neuroma or Morton’s Neuroma) is a benign(non-cancerous) enlargement of the third common digital branch of the medial plantar nerve.

 

Symptoms of Mortons Neuralgia

  • -shooting pain
  • -numbness and/or tingling in the third and fourth digits
  • -burning sensation
  • -cramping
  • -feeling of “walking on a lump” in the ball of the foot.

 

Anatomy of Mortons Neuralgia

  • -The interdigital neuroma is a benign(non-cancerous) enlargement of the third common digital branch of the medial plantar nerve.
  • -This nerve passes deep to the deep transverse metatarsal ligament.
  • -The enlargement or neuroma is usually located at the level of the third and fourth metatarsal heads but often can be found just distal to the metatarsal heads.
  • Mortons Neuralgia

Causes:

  • -ischemia (poor blood flow)
  • -presence of an intermetatarsal bursa (due to chronic irritation)
  • -pronation (flat foot)
  • -Equinus (tight hamstring)
  • -trauma
  • -anatomic thickness of the nerve in the third interspace (genetic)

-Bottom line- the nerve gets impinged somehow and causes swelling & irritation

 

Diagnosis:

  • -Mulder Test- Squeeze the foot from side to side & move fingers in the 3rd interspace to feel a click
  • -You should be able to feel a big ball between the 3rd and 4th toe joints
  • -MRI, X-ray & Ultrasound confirm it

 

Non-Surgical Treatment
Goal- Decrease pressure & irritation on nerve

 

 

  • 1)Metatarsal pads & orthotics can help alleviate pressure and assist in spreading the metatarsal heads ***This has a 41% cure rate according to studies***
  • 2)Corticosteroid and local anesthetic combination injection is commonly used. Typically, 1 to 3 injections are given.

 

  • ***80% initial success for 1-3 months, but after 4 years only 11% had permanent relief**
  • ***Another Study shows that 60-80% of corticosteroid & lidocaine combinations had relief on a 2 year followup**
  • ***Best results came with an Ultrasound guided injection needle – 82% relief on 12 month checkup***

Bottomline

  1. – About 40% cure with orthotics/Pads
  2.  -About 60% with steroids/lidocaine injection
  3.  -About 80-85% with a combination of both
  4.   -About 15% of people will need the nerve killed with injections or surgery  orthotic support

 

Alcohol Sclerosing injection

  • -Injection of a 4% alcohol sclerosing solution has shown complete relief of their symptoms. This injection was given in a series of 3 to 7 injections at 5- to 10-day intervals.
  •         ***a success rate of 89%, with 82% of patients relaying  complete relief of symptoms***
  • -Corticosteroid and alcohol sclerosing injections have been used under ultrasound guidance.
  •        ***partial or total pain relief in 94% of patients, with 84% totally pain free after 10 months***

Surgical management
-Surgical excision remains the most common procedure for Morton neuroma. It is most commonly performed through a dorsal or plantar longitudinal incision approach. these procedures are essentially the same, with the same goal of neurectomy (to simply cut out the nerve), differences exist in the dissection. You will lose feeling in the area after this surgery.

  1. Dorsal Approach (from the top)- The dissection is more difficult and more inter-operative complications may occur.
  2. Plantar Approach (from the bottom)- The dissection is very easy with little complications, but you must be in a surgical boot for 2-3 weeks so a scar or keloid doesn’t develop at the bottom of your boot.

Unique Surgical Options for Mortons Neuralgia

  1. Nerve decompression- is performed by releasing the deep transverse metatarsal ligament. – this requires a small cut from inbetween the webspace of the 3rd and 4th digits. The ligament above the nerve is cut to allow the nerve to expand. Although this has little complications and feeling remains in your foot – the pain may not go away. Usually if the surgeon observes the nerve as very thick they will just cut it out.
  • *** The nerve was excised in 46 of the 69 cases; the nerve was preserved in 23 cases with release of the deep transverse metatarsal ligament. Total relief of symptoms was appreciated in all but one from each group. Thus results were almost 100% successful after surgery***

 

Unproven Surgical Options for Mortons Neuralgia

  1. Cryogenic Neuroablation- this is a minimally invasive procedure that freezes the nerve at -50 to -70 degrees celsius- the results are not permanent and the procedure is unproven with research.

 

Complications of Surgery for Mortons Neuralgia

Most Common in descending order

  • 1)Stump neuroma – caused by not resecting the nerve proximal enough, incomplete excision, or tethering of the nerve to the plantar aspect of the metatarsophalangeal joint or other structures.
  • 2)One study found that 54% of the time there is a tarsal tunnel irritation at the proximal tibial nerve as well & this is why the surgery did not work.

 

Less Common

  • 3)Damage to the digital arteries- This occurs almost 30% of the time according to some studies- although this almost always leads to no ill effects due to formation of collateral vessels to compensate.
  • 4)Hammertoe formation- the toes can splay if the deep transverse inter tarsal ligament required resection

Very Rare

  • Keloid formation, complex regional pain syndrome.

 

 

References:

http://en.wikipedia.org/wiki/Morton’s_neuroma
Clinics in Podiatric Medicine and Surgery
Volume 27, Issue 4, October 2010, Pages 535–545