​Kembara Xtra - Medicine - Morton Neuroma

​Kembara Xtra - Medicine - Morton Neuroma
The common digital nerve has perineural fibrosis as it travels between the metatarsals, causing pain in the toes' webbed areas.
- The most common afflicted area is the interspace between the third and fourth metatarsals. The next most frequent location is the interspace between the second and third metatarsals.
Nervous and musculoskeletal systems are both affected.
Synonyms include Morton metatarsalgia, plantar digital neuritis, and intermetatarsal neuroma.

Epidemiology 

Unknown prevalence, mean age of 45 to 50 years, and a gender imbalance of 8:1 in favor of women over men.

Pathophysiology and Etiology 

The lateral plantar nerve joins a section of the medial plantar nerve, resulting in a nerve with a bigger diameter than those supplying the other digits. Four major hypotheses:
- Chronic traction injury - Intermetatarsal bursitis-induced inflammatory environment - Deep transverse intermetatarsal ligament compression - Vasa nervosa ischemia
The strong, deep transverse metatarsal ligament, which maintains the metatarsal bones together, is just superficial to the nerve, which is located in SC tissue, deep to the fat pad of the foot. The irritated nerve becomes crushed between the surface and the deep transverse metatarsal ligament with each step the patient takes. This may cause a perineural fibrotic response and the development of neuromas.

High-heeled shoes put extra weight on the forefoot, which is a risk factor.
Shoes with small toe boxes put pressure on the side of the foot.
Obesity, female gender, ballet dance, especially while in the demipointe posture, basketball, aerobics, tennis, running, and similar activities, hyperpronation, and pes planus (flat feet), which pulls the nerve medially and causes pain.


Basic Prevention 
Avoid high heels and shoes with tight toe boxes, and always wear shoes that fit properly.


History The most frequent complaint is pain that is restricted to the region between the third and fourth toes.
Pain subsides when you are not carrying any weight.
 Radiation of pain to the toes Pain is eased by taking off shoes and rubbing the foot. Pain, cramping, or numbness of the forefoot during weight bearing or just after heavy foot exertion.
Patients sometimes gripe about "walking on a marble."
 A burning ache that radiates to the toes from the ball of the foot
 Numbness or tingling in the toes, made worse by wearing small or narrow shoes

clinical assessment 
Severe pain with pressure between the metatarsal heads, perhaps accompanied by a palpable nodule
 Examine midfoot motion and digital motion to rule out synovitis or arthritis.
 Feel along the metatarsal shafts to check for stress fractures or metatarsalgia.
 Extensive testing


Differential diagnosis: Hammer toe, stress fracture, metatarsophalangeal synovitis, osteomyelitis, bursitis, foreign body, Freiberg infraction (avascular necrosis of the metatarsal head, most frequently affecting teenage girls at the second metatarsal), neoplasm (malignancy, osteochondroma, neurofibroma), gout, and more.

Initial test results from the laboratory and imaging
Predominantly a clinical diagnosis; imaging should only be used in cases of doubt about the diagnosis.
If more than one online space is involved, imaging might be useful.
If the diagnosis is uncertain, radiographs may help rule out osseous pathology, but plain films are typically normal in Morton neuroma patients.
While US is 99% sensitive and 79% specific for Morton neuromas, it is not very good at determining the size of the lesion. Specificity drops to 50% for lesions smaller than 6 mm.
When used to diagnose Morton neuromas, MRI has a sensitivity of 83% and a specificity of 99%. It can also help with surgical planning.


Other/Diagnostic Procedures
The thumb index finger squeeze test, Mulder sign, foot squeeze test, plantar percussion test, and toe tip sensory deficiency are five unique tests that have been described.
The most sensitive and specific test is the thumb index finger squeeze test (96% and 96%, respectively). Positive when symptomatic intermetatarsal gap between the index finger and thumb causes pain.
- The neuroma between the thumb and index finger of the other hand is compressed as the metatarsal heads are squeezed together to generate the painful "click" known as the Mulder sign; sensitivity ranges from 40 to 84 percent. 
- The foot squeeze test is considered positive if it causes discomfort in the affected web region when the metatarsal heads are squeezed; sensitivity 40% 
- Plantar and dorsal percussion tests are successful if pressing on the area with the afflicted webspace causes discomfort.
When the sensation of the toe distal to the afflicted web space is diminished in comparison to the other toes, a toe tip sensory deficit is present.
If more than one of the aforementioned tests is positive, the diagnostic precision is increased.
Interpretation of Tests
The digital nerve has thickening and chronic fibrosis, according to a pathologic investigation. There may occasionally be thrombosis and arterial thickening of the common digital artery.

Management 
Stepwise approach to treatment, with a normal progression from preventative measures to infiltrative therapy to surgical therapy.
According to patient satisfaction with pain reduction at 6 months or longer, surgical therapies are the most effective (89%) followed by infiltrative (84%) and conservative (48%).
Simple remedies include wearing flat shoes with a large toe box.
- Plantar pads or a metatarsal bar may be able to relieve pain by assisting the alignment of the metatarsal heads.
Varus or valgus footwear cushioning and extracorporeal shock wave therapy (ESWT) have no place in treatment.
NSAIDs can alleviate symptoms momentarily

First Line of Medicine
Number needed to treat (NNT) for significant benefit over conservative measures for injectable steroids (such as betamethasone phosphate/acetate or methylprednisolone) at 6 months = 2.3 One study showed clinically significant improvement in the use of US guidance versus palpation for corticosteroid injection.
It is successful and less prone to complications than surgery to sclerose the nerve using second-line US-guided alcohol ablation therapy.


referral, large interdigital neuromas (>5 mm in diameter), or young patients who might benefit from earlier surgical intervention. One study showed that a cut-off value of 6.3 mm or larger Morton neuroma was associated with failure of corticosteroid injection.


Surgical Techniques According to satisfaction ratings at 6 months, surgical excision of the neuroma or shortening of the metatarsals, with or without release of the transverse metatarsal ligament, has an 89% success rate.
Other invasive, nonsurgical procedures such botulinum toxin injection, cryoablation, radiofrequency ablation, and platelet-rich plasma have also been the subject of small trials, but the evidence is still sparse at this point.

Consider corticosteroid injection if there has been no improvement after three months of conservative treatment or at the time of diagnosis.
If there is still no improvement after 2 to 4 weeks, the patient may repeat the injection or be referred for surgical treatment.
Within two to four years after receiving a single corticosteroid injection, 21-51% of patients need surgery.
Patients with a size >5 mm and those who are younger are more likely to receive intrusive therapy.


Education of Patients 
Wear comfy shoes that fit you appropriately.

Prognosis: 48% of patients with conservative treatment are satisfied, 85% of patients with infiltrative treatment are satisfied, and 89% of patients with surgical treatment are satisfied. 


Complications Depending on the type of treatment, there may be hip and knee discomfort that develops as a result of changes in gait.
Surgical consequences can include keloid, CRPS, and stiffness, and the failure rate is 47% with conservative treatment, 9-23% with invasive, nonsurgical treatment, and 4% with surgical treatment. The overall complication rate for surgical therapy was 21%.

---