What is a ‘Bursal – Neuromal Complex’
(How does it differ from Intermetatarsal Bursitis and a Neuroma?)
A ‘Bursal – Neuromal complex’ is a recent term suggested by Cohen, et al. 2016 (5).
This term is an update and more accurate description of the commonly used diagnostic term of ‘intermetatarsal bursitis, interdigital neuroma or Morton’s neuroma‘
The study compared the sonographic findings of the interdigital mass (commonly referred to as an interdigital neuroma or bursitis) to the pathological findings after surgical excision of the mass.
They concluded that the interdigital masses viewed with an ultrasound were a combined appearance of the:
“degenerated nerve, perineural scarring, tangled vessels, and scarred inter-metatarsal bursa” Cohen, et al. 2016 (5).
As with a neuroma or intermetatarsal bursitis a ‘bursal – neuromal complex’ often presents as pain on the ball of the foot.
Neurological symptoms are also common including burning, tingling, numbness and pain in the region of the forefoot reflective of the neurological component of the mass.
What Causes a “Bursal – Neuromal Complex”?
The exact cause of a ‘Bursal – Neuromal complex‘ is unclear.
It is thought that the interdigital mass is the result of a combination of a compression trauma and ischemic (lack of blood flow) entrapment of the intermetatarsal structures (3, 6, 7, 8, 9)
(see the diagram below of a cross section of the forefoot). 
It has been suggested that the common plantar digital nerve and bursa are repeatedly compressed, resulting in chronic irritation. Over time the repeated irritation results in the subsequent development of a benign fibrotic and mucoid degeneration of the nerve and bursa (3, 5, 6, 7, 8, 9).
The irritation of the nerve is thought to be made worse with:
- Tight fitting footwear
- Hypermobile joints
- Digital deformities (clawtoes or (Hallux valgus) bunions)
- A flat foot
- A high arched foot
Diagnosis of a Bursal Neuromal Complex?
Diagnosis is usually based or symptoms and a complete assessment of your foot and ankle.
Ultrasound Examination of the forefoot is also beneficial to determine the presence of the inter digital mass. Typically a ‘bursal-neuromal complex’ will present as a non compressible mass between the web space as shown in the pictures and videos below.
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Treatment of a ‘Bursal Neuromal’ Complex
Treatment aims to reduce the disorganisation of the neural and bursal mass and also offload the forefoot to prevent its re-occurrence.
1. Reduction of the disorganised mass can be achieved with
- Shockwave therapy
- Ultrasound guided injection therapy
- Cortisone Injection (51% success rates) (16)
- Alcohol (Ethanol) Sclerosis (71% success rate) (16)
- Radiofrequency nerve ablation (84% success rate) (16)
- Surgical Excision (88% success rate) (16)
(percentage success rate from a recent systematic review published in 2017 by Valisena click here for the article)
2. Offloading the interdigital mass can be achieved with
- Shoe stretching and modification (rocker sole modification)
- Metatarsal domes
- Custom made Orthotics with a metatarsal dome incorporated into the design
What else could it be? (differential diagnosis)
Other problems that can cause similar pain to a ‘Bursal – Neuromal Complex’ include:
- Inter metatarsal bursitis
- Neuroma
- Mortons Neuroma
- Corns
- Plantar plate pathology
- Freibergs infraction
- Metatarsal stress fracture
The Ankle, Foot and Orthotic Centre’s Northcote Podiatrists can help you with all lower limb complaints, including pain from a “Bursal Neuromal Complex” . Make an appointment to get your foot and ankle pain under control.
Call The Ankle Foot and Orthotic Centre for diagnosis and advice on professional management and treatment options.
References
1.Bossley CJ, Cairney PC. The intermetatarsophalangeal bursa–its significance in Morton’s metatarsalgia. J Bone Joint Surg Br. 1980;62-B(2):184-7.
2.Giakoumis M, Ryan JD, Jani J. Histologic Evaluation of Intermetatarsal Morton’s Neuroma. Journal of the American Podiatric Medical Association. 2013;103(3):218-22.
3.Stecco C, Fantoni I, Macchi V, Del Borrello M, Porzionato A, Biz C, et al. The role of fasciae in Civinini-Morton’s syndrome. J Anat. 2015;227(5):654-64.
4.Bianchi S. Practical US of the forefoot. J Ultrasound. 2014;17(2):151-64.
5.Cohen SL, Miller TT, Ellis SJ, Roberts MM, DiCarlo EF. Sonography of Morton Neuromas: What Are We Really Looking At? J Ultrasound Med. 2016;35(10):2191-5.
6.Wu KK. Morton neuroma and metatarsalgia. Curr Opin Rheumatol. 2000;12(2):131-42
7.Decherchi P. [Thomas George Morton metatarsalgia]. Presse Med. 2007;36(7-8):1098-103.
8.Rajput K, Reddy S, Shankar H. Painful neuromas. Clin J Pain. 2012;28(7):639-45.
9.Perini L, Borrello MD, Cipriano R, Cavallo A, Volpe A. Dynamic sonography of the forefoot in Morton’s syndrome: correlation with magnetic resonance and surgery. Radiol med. 2006;111(7):897-905.
10.Bignotti B, Signori A, Sormani MP, Molfetta L, Martinoli C, Tagliafico A. Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis. Eur Radiol. 2015;25(8):2254-62.
11.Zanetti M, Weishaupt D. MR Imaging of the Forefoot: Morton Neuroma and Differential Diagnoses. Seminars In Musculoskeletal Radiology. 2005;09(03):175-86.
12.Chauveaux D, Huec JCL, Midy D. The supra-transverse intermetatarsocapital bursa: a description and its relation to painful syndromes of the forefoot. Surg Radiol Anat. 1987;9(1):13-8.
13.Lee M-J, Kim S, Huh Y-M, Song H-T, Lee S-A, Lee JW, et al. Morton Neuroma: Evaluated with Ultrasonography and MR Imaging. Korean J Radiol. 2007;8(2):148-55.
14.Kankanala G, Jain AS. The Operational Characteristics of Ultrasonography for the Diagnosis of Plantar Intermetatarsal Neuroma. The Journal of Foot and Ankle Surgery.46:213-7.
15. Fazal MA, Khan I, Thomas C. Ultrasonography and magnetic resonance imaging in the diagnosis of Morton’s neuroma. Journal of the American Podiatric Medical Association. 2012;102(3):184-6
16.Zanetti M, Weishaupt D. MR Imaging of the Forefoot: Morton Neuroma and Differential Diagnoses. Seminars In Musculos