Mortons Neuroma: Accuracy of Ultrasound

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Hi All

Can anyone enlighten me on the accuracy of US in the diagnosis of mortons neuroma in patients with the mulders click??

ta very muchly

 

Re: Mortons Neuroma Accuracy Of US

This might help.

 

thanks folks!

 

It was not that long ago that that surgeons relied on cilinical judgement for possible neuroma. and my experience was that it was rare not to find a neuroma at surgery after making a diagnoses. Now with sometimes unfounded fear of litigation everything goes for ultrasound scan. I find that even with a negative scan if pain persists and conservative methods fail going in to explore will more than often produce a mortons neuroma. It would be interesting to hear of others experiece. The question is " are we scanning just to cover our backs"?

 

I would be interested to hear how many people use local anaesthetic as a diagnostic tool in cases of suspected neuritic problems.

 

6. Hewett S. Kilmartin T. O’Kane C (2007) A retrospective audit on the role of sonographical interpretation and localisation of intermetatarsal neuroma in the surgical management of Morton’s neuroma, Journal of Podiatry, 10, (3) B, 99-103

7. Irwin L. Konstantoulakis C. Hyder N. Sapherson D (2000) Ultrasound in the diagnosis of Morton’s neuroma, The Foot, 10, 186-189

8. Jones S. Bygrave J. Betts P. Smith, T.W.D. (1999) Morton’s neuroma: a sonographic-surgical evaluation. The Foot, 9, 189-192

9. Kankanala G. Jain A (2007) The Operational Characteristics of Ultrasonography for the Diagnosis of Plantar Intermetatarsal Neuroma, The Journal of Foot and Ankle Surgery, 46, (4), 213-217


11. Lee M. Kim S. Huh Y. Song H. Lee S. Lee J. Suh J (2007) Morton Neuroma: Evaluated with Ultrasonography and MR Imaging, Korean Journal of Radiology, 8, 148-155


14. Miller S. Nakra A (2001) Morton’s Neuroma. In Banks et al (Eds) McGlamrys Comprehensive Textbook of Foot and Ankle Surgery, 3rd edition, Vol.1, Philadelphia, Lippincott Williams & Wilkins, p. 231-252

15. Mendicino S. Rockett M (1997) Morton Neuroma Update on Diagnosis and Imaging, Clinics in Podiatric Medicine and Surgery, 14, (2), 303-311







22. Pollak R. Bellacosa R. Dornbluth N. Strash W. Devall J (1992) Sonographic Analysis of Morton’s Neuroma, The Journal of Foot Surgery, 31, (6), 534-537

23. Quinn T. Jacobsen J. Craig J. van Holsbeeck M (2000) Sonography of Morton’s Neuromas, American Journal Roentgenology, 174, 1723-1728

24. Read J. Noakes J. Kerr D. Crichton K. Slater H. Bonar H (1999) Morton’s Metatarsalgia: Sonographic Findings and Correlated Histopathology, Foot & Ankle International, 20, (3) 153-161


25. Redd R. Peters V. Emery S. Branch H. Rifkin M (1989) Morton Neuroma: Sonographic Evaluation, Radiology, 171, (2), 415-417



28. Shapiro P. Shapiro S (1995) Sonographic Evaluation of Interdigital Neuromas, Foot & Ankle International, 16, (10), 604-606



30. Sobiesk G. Wertheimer S. Schulz R. Dalfovo M (1997) Sonographic Evaluation of Interdigital Neuromas, The Journal of Foot & Ankle Surgery, 36, (5), 364-366


32. Williams R. Grace D. Papas G (1996) Ultrasonography in the diagnosis of Morton’s neuroma, The Foot, 6, 159-162




These are the references for the use of US from my PGc ultrasound case study

 

Nearly always if considering injection therapy or surgical referal I will do diagnostic injection. I use US when I suspect plantar digital neuritis but rarely see the classic presentation on US described in the papers cited. I think it is a difficult exam to get unequivocal evidence for a couple of reasons.

Normal plantar fibro-fatty pad at the inter-metatarsal space and fibrous tissue adjacent to the plantar digital nerve have very similar sonographic appearance other than behaviour to compression (fat compresses fibous tissue doesnt)

the inter-metatarsal space bursa mnormally doesnt extend distal to the deep transverse intermetatarsal ligament but is a common finding so it is not very specific for plantar digital neuritis if for example present at 2/3 and 3/4 inter-metatarsal spaces. A diagnostic injection is the only way to improve specificity since pain may be from neither one or both locations in this case.

I find the literature very lacking in describing what I would regard as a reasonably clear reasoning process for using US for examining the inter-metatarsal space, but this is also true of much of what is published regarding the nature of the so called mortons neuroma too.

cheers


Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

Just wanted to clarify my comment which is confusing.

the inter-metatarsal space bursa doesnt normally extend distal to the deep transverse intermetatarsal ligament at the 1st and 4th inter-metatarsal space BUT does at the 2nd and 3rd inter-metatarsal space.

If you look at most of the medical literature describing the appearance of "Morton's neuroma" with US it shows a hypoechoic or anechoic zone nicely positioned superficial to location of neurovascular bundle within the plantar fibro-fatty pad at level of proximal phalanx.

To clarify my point:

I find that many who have symptoms of plantar digital neuritis, and who subsequently are rendered symptom free following guided infiltration of 0.3 mls 1% lidocaine into bursa rarely show these unequivocal anechoic signs which are described in most papers.

What this suggests to me is that the specificity of the "superficial" sign may be high, as medical literature suggests, but may lack sensitivity in terms of evidence for nerve compression, particularly in early or mild cases.

I think part of the problem of interpreting the US is linked to the relevence of the nature and position of the space filling lesion.

Since nerve compression may be caused by forces from the bursa deep to the nerve (as well as superficial to it) the histologic nature of surgically removed tissue may not neccessarily explain the cause of plantar digital neuritis simply because of the presence or absence of fibrous elements (they are common finding in cadavers).

It would however seem likely that presence of bursa superficial to neurovascular bundle and/or incompliant fibrous tisse adjacent to nerve (true but mislabeled "neuroma") would be related to DEGREE of symptoms and FAILURE to conservative approach be that by optimising mechanics with foot orthoses/foot-wear or injection therapy; this seems to be case in my experience.

US may then have a useful role in predicting the RESPONSE for conservative treatment but to my knowledge this study has not been done.

cheers

Martin

The St. James Foot Clinic
1749 Portage Ave.
Winnipeg
Manitoba
R3J 0E6
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

Morton's neuroma: A clinical versus radiological diagnosis
Philip Pastides, Sameh El-Sallakh, Charalambos Charalambides
Foot and Ankle Surgery; Volume 18, Issue 1, March 2012, Pages 22–24

 

I agree in the main that the benefit of US is determining which and how many interspaces are affected. I wouldn't wish to deploy steroid into a non-pathological interspace. I would add further that the real time imaging of US allows the operator to determine for compressibility of the lesion under interrogation, as some propose that neuromata are relatively less compressible than bursitis, but they probably co-exist in many cases.

 

Hi Peter

You might be interested in this paper; it is the most thoughtful I have read addressing the issues of US interpretation and has several examples of comparison of post surgical visual morphology of lesions vs corresponding US pre-surgery which I have not seen published elsewhere. I think the GL sign which the authors developed is a nice addition to way of thinking about sonographic signs and had been thinking along the same lines myself.

I am currently working up a research proposal to evaluate reliability/accuracy of 3D US imaging of the inter-metatarsal space neurovascular bundle.

Please email me

martincolledge@shaw.ca

I would be keen to chew the fat with you in this.

Cheers

Martin
Foot and Ankle Clinic
1365 Grant Ave.
Winnipeg Manitoba R3M 1Z8
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com


SONOGRAPHIC APPEARANCES OF MORTON’S NEUROMA: DIFFERENCES
FROM OTHER INTERDIGITAL SOFT TISSUE MASSES
HEE-JIN PARK,*y SAM SOO KIM,y MYONG-HO RHO,* HYUN-PYO HONG,* and SO-YEON LEE*
*Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic
of Korea; and yDepartment of Radiology, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
(Received 26 January 2011; revised 3 May 2011; in final form 9 May 2011)
Abstract—The purpose of the study was to evaluate the ultrasonographic characteristics of Morton’s neuroma
(MNs) and the usefulness of the ‘‘ginkgo leaf sign’’ for differentiating MNs from other interdigital soft tissue
masses. The inclusion criteria were 27 patients with the masses in the intertarsal region with surgical proof. Fourteen
masses in the 10 patients (mean age, 46) were MNs and nine cases of nine patients were ganglion cysts, seven
cases (seven patients) of epidermoid tumors and one case of fibroma were included. Ultrasonographic examinations
were performed by a musculoskeletal radiologist using the HDI 5000 (Philips, Bothell,WA, USA) or the Logiq
E9 (GE Medical Systems, Milwaukee, WI, USA) equipped with a linear 6–15 MHz probe, and the findings were
interpreted in consensus by two musculoskeletal radiologists. The ultrasonographic findings such as margin,
size, echogenicity and deepness of the MNs were compared with those for other interdigital soft tissue masses.
The ginkgo leaf sign was defined as the appearance of a biconcave shape of the mass from compression by adjacent
structures. The mean size of the MNs was 5.6 mm. There was a significant difference in incidence between males
and females (female dominant, p 5 0.003). There was no difference in incidence with regard to age (p 5 0.259). All
lesions were hypoechoic (100%, 14/14) and 10 cases exhibited the ginkgo leaf sign (71%, 10/14, p , 0.001). The
lesions were either well marginated (43%, 6/14) or poorly marginated (57%, 8/14, p 5 0.075). None of the lesions
abutted adjacent bony structures (p , 0.001). Interdigital MNs are primarily found in middle-aged women and
often demonstrate the ginkgo leaf sign. MNs are hypoechoic and do not abut adjacent bony structures. Based
on our findings, we believe ultrasound of interdigital soft tissue masses may provide useful information with respect
to their location to adjacent soft tissue structures. Detection of our Gingko leaf sign may be specific for Morton’s
neuromas and more studies are needed to confirm its value as a sonographic sign. (E-mail: parkhiji@kangwon.
ac.kr)
2011 World Federation for Ultrasound in Medicine & Biology.
Key Words: Ultrasound (US), Morton, Neuroma, Soft tissue, Tumor.

 

My problem with US is that whilst it might show you whats there, it won't show you if thats the bit which hurts!

 

Hi Robert

That is true of any imaging; it does have potential though to give us useful information which may allow us to infer root of pain. As always, the issue is to use this information in context, understand its limitations, and probe the specificity and sensitivity of these tests.

I thing an important issue with plantar digital neuritis is that we still don't really have a firm evidence based grasp of what is actually going on.

If you look at cadaver studies, the limited evidence suggests that "neuromas" are a common finding and may be asymptomatic in some individuals. I believe that it is likely, like many MSK issues, that plantar digital neuritis may have multifaceted etiology and variable on an individual basis which makes definitive research difficult. Makes life more interesting though. I am interested to try and establish the variability of the position of neurovascular bundle. Perhaps an important issue is its location relative to the metatarsal head during weight-bearing. I am curious for example why so many (I would estimate 80%) of those I see with provisional diagnosis of plantar digital neuritis have resolution simply by uncompromising use of foot-wear which doesn't compress forefoot.

Cheers

Martin

Foot and Ankle Clinic
1365 Grant Ave.
Winnipeg Manitoba R3M 1Z8
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

Because (and no offence to you Mart) the bleeding obvious, is more often than not, the bleeding obvious....... http://www.podiatry-arena.com/podiatry-forum/showpost.php?p=247165&postcount=18

 

totally agreed . . . . but the bleedin obvious aint always true.

If you are up for it post what you think is "bleedin obvious" in the case of foot-wear causing plantar digital neuritis and lets see what that amounts to


:drinks

Cheers

Martin

 

I thought I already had... but you obviously know more...

 

OK then . . . I’ll bat first.

As we were exchanging pleasantries I saw a 47 yo male, reported being in good general health, no medications, no relevant comorbidity for right foot non specific metatarsalgia. He stepped barefoot on a wooden peg 6 weeks ago with sudden pain – recalled this being under 1st metatarsal head – patient attributed this to cause of current problem, there was no reported associated swelling, bruising or wound. He had no immediate unusual pain after the incident. He has run for several years on indoor track 30 minutes 3 X per week but has stopped running because current threshold of pain is approximately 5 minutes walking or running. There is radiating pain into digits 3 and 4 during episodes of metatarsalgia which seems focused distal to 3rd metatarsal head. Pain resolves within minutes with rest. He has not changed foot-wear or activity level immediately prior to or since onset of problem other than stopped running. Occupation is sedentary, mostly non weight bearing at work

I observed: no signs of swelling, erythema, heat or skin lesions. Slight tenderness to palpation at 2nd and 3rd inter-metatarsal spaces, no Mulders sign, He has no reducible or fixed flexion deformity of digits or hallux valgus. There was no evidence of functional hallux limitus evidenced by elevated passive first metatarso-phalangeal joint dorsiflexion stiffness with passive first ray dorsiflexion. Provocative testing with single limb stance heel raise resulted in recreation of pain. There was no pain with passive range of motion of metatarso-phalangeal joints and no evidence of plantar plate attrition. Foot-wear were notably too much too narrow and forefoot notably wider than average.

He asked me what was wrong and I said “its bleeding obvious your shoes are too narrow”

And he said “well I have been wearing these shoes for past six months how come I have a problem all of the sudden?”

And I said “well I dunno”

So on surface it is bleedin obvious that he has plantar digital neuritis which may be associated with foot-wear (or not).

What would you do at this stage?

If the bleedin obvious is true then how would you explain his phenomenon?

Speculating I would say could be any or non of below:

Patient has been on threshold of compression (from normal inter-metatarsal space structures) related plantar digital neuritis for a while and alteration to plantar forces in response to initiating injury reduced headroom and threshold now exceeded.

Injury was moot and pain is early effect of peri or intraneural hyaluran degeneration prior to an obvious lesion forming

inter-metatarsal space bursa enlargement adjacent to plantar digital nerve of no apparent cause or 1 above

Plantar fibro-fatty pad intolerance to elevated peak pressures or force time integrals

So is it important to understand this better?

I think so – non specific metatarsalgia is extremely common and suspicion for plantar digital neuritis in absence of digital pain often somewhat ambiguous.

Typically we won’t be able to “watch” a neuroma developing although US may allow this progression to be “captured” in those with early stages if problem doesn’t respond to treatment.

I doubt this is anything you haven’t considered.

I value your opinion but disagree that this, which is a common generalized presentation, is really that bleedin obvious?

Also given the evidence how should we proceed?

You show me yours and I’ll show you mine (anyone?)

Cheers

Martin

Foot and Ankle Clinic
1365 Grant Ave.
Winnipeg Manitoba R3M 1Z8
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

I also meant to add that the examples which you and Robert gave are pretty unusual my experience - the example I just posted I would say is typical - perhaps we are not talking about similar presentations ???

Cheers

Martin

 

Martin,
I'd go with a threshold model, and put him in wider shoes.

 

Hi Mart,

I will drop you an email in due course, and many thanks for the paper, will read it ASAP and get back to you. One of my biggest bugbears is radiology papers identifying MN by a presumed hypoechoic appearance, when during my US training, all fibrotic tissue elsewhere in the MSK system is hyperechoic. I assume this is due to co-existing bursitis, or exclusively bursitic in nature and not a MN. This is why i tend to lean towards compressibility to help Dx, which is valubale given the real-time nature of Dx US.


I would value your thoughts.

 

Intermetatarsal neuromas are a relatively common finding (established through Mulder's sign) even in asymptomatic individuals. This is also true of plantar plate tears with one cadaver study estimating that over 90% of plantar plates had some form of tear in it.

I only focus on these, obviously, when they are symptomatic. For neuromas, it is likely that the cause of pain is mechanical irritation caused by the nerve having too much pressure on it. Typically, this is caused by a shoe with too little volume within the toe box region of the shoe so that there is likely a signficant increase in pressure on the affected nerve with these shoes that "squeeze" the neuroma with each step.

With repetetive trauma, the nerve goes from a normal size to a much larger mass. In the office, I use the analagy of showing patients, with my pen the size of a normal nerve (the writing stylus of a pen) compared to the size of a large neuroma (barrel of the pen) which I demonstrate in the attached image. These dimensions are quite close to being very representative so that one can only imagine, as the neuroma becomes larger, the threshold for shoe tightness that causes symptoms becomes less and less over time.

Every now and then, when I am feeling feisty with a patient, I tell them that the cause of the their neuroma is that they are trying to put 10 pounds of potatoes into a 5 pound potato sack with the way they are fitting their shoes. That generally gives patients a pretty good mental image of what is causing their pain.

 

Hi All

The initial thread was:

"Can anyone enlighten me on the accuracy of US in the diagnosis of mortons neuroma in patients with the mulders click??"

The medical literature is pretty convincing regarding the sensitivity and specificity of US to detect "Mortons neuromas" (MN), there have been many studies which mostly support using US along with MR as a primary imaging method for suspicion of MN. There seems to have been some concern, perhaps I am overly reading between the lines, that US is unnecessary or irrelevant in presence of suspicion of inter-metatarsal space masses. Although the comments regarding other obvious causes of metatarsalgia are kind of obvious in themselves, it might be interesting to consider what US has has to offer in those less obvious cases of "MN like" symptoms" which I find in my practice to be the majority.

The role of the Mulders sign (MS) diagnostically is controversial; some studies suggest it is useful others not. I have seen unequivocal MN like masses on US without MS and unequivocal absence of mass with a MS. I don't think that most surgeons would be comfortable cutting based on solely on presence of plantar digital neuritis and MS; please post a disagreement if that seems unsound.

Peter also mentioned what I think is an important omission in US literature which is that ALL US studies published use a hypoechoic zone as their diagnostic criteria. This certainly then excludes a purely fibrous lesion. I have never seen this discussed elsewhere; perhaps it is because in conventional terms a MN will always have a significant hyaluran presence, I am not sure about this.

Where I think US may have an important role; perhaps as more pods start using it as part of their physical exam, is in questioning what a MN actually amounts to. On the surface it seems BO but my impression is that most surgeons have their lesions biopsied primarily to answer 2 questions. Was the nerve removed, and was an artery removed? The actual histology of the lesion otherwise being somewhat moot.

Another important question to be explored is idea of plantar digital neuritis in absence of a significant MN like mass.

I believe from my own experience that this is far more common than presence of MN. Although considered "old ideas" the question of the role of ischaemia, other causes of nerve compression, tension or torsion remain unanswered. I find it interesting that in most cases of plantar digital neuritis in absence of MN there is usually evidence of inter-metatarsal space bursa enlargement adjacent to plantar digital nerve. It is also most common to find this qualitatively in contralateral foot which is not symptomatic. This is not reported in the medical literature. 3D US may have the capacity to understand this better by being able to quantify and map the inter-metatarsal space more precisely. Another observation I find interesting is the apparent variation in presence/absence of plantar digital artery at the 2nd and 3rd inter-metatarsal spaces and its proximity to the metatarsal head. As we know the anatomy of this region may be often disturbed by instability of the metatarso-phalangeal joints; it seems plausible then that plantar digital neuritis may be a result of either congenital or acquired deviation of the neurovascular bundle closer to zone of increased weight-bearing force.

Currently our therapies involve optimizing foot-wear fit, applying ground reaction forces in ways which we believe to reduce injurious pressures, injection of substances which we aren't entirely sure of their effects.

Sometimes non of these work and that is frustrating all round. It is unclear if they don't work because they are poorly applied or if there are things which we don't understand yet.

I guess that is why I didn't want this thread to end with a notion that MN is a cut and dry issue which is mostly BO.

Cheers

Martin

Foot and Ankle Clinic
1365 Grant Ave.
Winnipeg Manitoba R3M 1Z8
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

I like your thought process [impressive, to say the least] in the 1st one and your input/feedback [humbling] in the 2nd one. It is fascinating to find that we can still explore a topic to the edge of a precipice of the boundaries of the known and unknown.
For my part, I was on a roll for several years never having 'missed' a diagnosis until that once... then, I decided that -in the mid-2000's- I would 'spin-up' my radiologist in my army hospital w/ a protocol (and she finally decided to buy a small (hand/foot) US wand, and we got good at spotting these things (both of us took a mini-course @ a conf.). It's frustrating to NOT be able to see squat on an $pesnive MR (we had to wait for (from downtown) when you know something BIG is in there!
For those little ones, and those tight IM spaces, hey that Percutaneous IM Space Release can work very nice, and I (so far) have never had to go back and get one via open method (no worries, I'm not superstitious).
As for dorsal approach, never again: after getting "surprised" once or twice- I go plantar now... and recall a surgeon or two at CCPM (now CSPM) -and a conf/wkshop or 2 since then saying that was their approach of choice. As of now, me too. They can be very plantar, big, and tough to get to otherwise; and much easier to access from below.
For the non-surgical patient, I do like Dockery's 4 or 6 % Sclerosing Sterile Alcohol in 0.5% Marcaine; just rem'ber, a series of 3 to 7 is indicated. It's usually knocked out by 3-4 in my experience. I like premedicating just a touch, topical (pt applies EmLa 1-2 hrs under kitchen plastc wrap), maybe Tyl + NSAID (or something stronger if they're a pain player, or a Valium if nervous type), and lots of Gebaur's-- don't spare the cold spray!
--WillTrekker
Horizon City, TX
"if you're not the lead dog, the view never changes"

 

Hi Will

I think your observations re MR are interesting. I think that sagittal view slices of MR may miss some important detail of inter-metatarsal space bursa because of gaps between images, this is obviously not true of US. Also the inability of MR to infer tissue stiffness compared to US is relative disadvantage.

Is there a podarena thread on percutaneous release (I presume deep transverse intermetatarsal ligament) technique? If not it would make interesting thread to create. Do you use US guidance when doing these procedures to optimize instrument placement?

I have had some success with ethanol injections too. One observation is that this doesn’t seem to cause any sensory change to digits and if this eliminates pain it suggests that this is unlikely neurolysis of plantar digital nerve. What then may affect be? I think there are two plausible explanations; sclerosis of bursa (reducing compression) or destruction of problematic sensory “spouts” from the nerve bundle.

Any thoughts or anecdotes about this? Do you notice swelling and pain post ethanol injection?

Cheers

Martin

Foot and Ankle Clinic
1365 Grant Ave.
Winnipeg Manitoba R3M 1Z8
phone [204] 837 FOOT (3668)
fax [204] 774 9918
www.winnipegfootclinic.com

 

Ultrasonography and Magnetic Resonance Imaging in the Diagnosis of Morton’s Neuroma
Muhammad Ali Fazal, Ishrat Khan, Cherian Thomas
J Am Podiatr Med Assoc 102(3): 184–186, 2012

 

Role of MRI in Detection of Morton’s Neuroma
Leif Claassen, Kilian Bock, Max Ettinger, Hazibullah Waizy, Christina Stukenborg-Colsman, Christian Plaass
Foot & Ankle International June 23, 2014 1071100714540888

 

The accuracy of ultrasonography and magnetic resonance imaging for the diagnosis of Morton's neuroma: a systematic review
Z. Xuc, X. Duanc, X. Yu, H. Wang, X. Dong, Z. Xiang
Clinical Radiology; Articles in Press

 

Ultrasound-Guided Diagnosis and Treatment of Morton's Neuroma.
Ata AM, Onat SS, Ozcakar L.
Pain Physician. 2016 Feb;19(2):E355-E358.

 

Intra‐ and Interobserver Reliability of Size Measurement of Morton Neuromas on Sonography
Young Hwan Park MD Won Seok Choi MD Gi Won Choi MD Hak Jun Kim MD, PhD
07 January 2019