Ultrasound-guided Radiofrequency Ablation of Morton's Neuroma

Transcription

1 Ultrasound-guided Radiofrequency Ablation of Morton's Neuroma Poster No.: P-0044 Congress: ESSR 2016 Type: Authors: Keywords: DOI: Scientific Poster R. Mazzetti, A. Cosentino, F. Gobbi, D. Righi, G. Gandini; Torino/ IT Hyperplasia / Hypertrophy, Ablation procedures, Ultrasound, Neuroradiology peripheral nerve, Musculoskeletal soft tissue, Interventional non-vascular /essr2016/P-0044 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 11

2 Purpose The Morton's neuroma (MN) is a painful clinical entity involving the common digital nerve of the foot. It is an interdigital entrapment neuropathy beneath the transverse metatarsal ligament (1)(2). The incidence of interdigital neuromas is more common in women in the fifth decade and it occurs in the third interspace (typical MN) more than in the second one (atypical MN) (ratio 2:1) (1)(3). The most common symptom is sharp pain localized to the forefoot that radiates to the toes, increased by activities on the foot: such as running, high-heeled shoe use and prolonged walking. Conservative treatment is the first-line management and include using of appropriate footwear, stretching, soft pads, steroids and alcohol injections. However, the majority of patients continue to have symptoms and, in time, 70% of them proceed to surgical excision (4). Pulsed radiofrequency ablation (RFA) has been recently proposed as less invasive and less traumatic procedure of treating neuromas (5)(6). It can be defined as the destruction of a limited volume of the myelin nerve periphery, utilizing energy generated from a radiofrequency wave (5). The aim of this prospective study was to assess the effectiveness of a single ultrasoundguided radiofrequency ablation for symptomatic Morton's neuroma. Methods and Materials The study sample comprised 13 women and 5 men (mean age 53,4 years), resulting in 19 Morton's neuromas (MN). All the subjects had a specialist orthopedic diagnosis of MN and, although had previously tried conservative management methods, still had unbearable symptoms and were surgical candidates for neurectomy. The MNs had been confirmed with ultrasound and/or magnetic resonance imaging and were measured in a first evaluation exam. The RFA procedure was performed by a musculoskeletal radiologist in ambulatory setting. Under ultrasound-guidance, a sterile 5 cm-long needle with an active tip was inserted, with plantar access, inside the neuroma ( Fig. 1 on page 3 ). The intra-lesion Page 2 of 11

3 needle position was assessed also by sensory stimulation as well as by US-imaging. After 0,5-1 ml of 2% lidocaine were injected, the RFA was performed three times at 80 C for 60 seconds each ( Fig. 2 on page 3 and Fig. 3 on page 5 ). The machine was a NeuroTherm NT1100 (Neurotherm, USA). At the end of the procedure all the patients were discharged home after 20 minutes of clinical observation with instructions to rest for the next day; they could use ice and paracetamol as necessary. The follow-up lasted for 1 year (Y) and included assessment of global foot function and pain. The first was assessed with the AOFAS (American Orthopedic Foot and Ankle Society) forefoot score (0-100 points) (7) that was evaluated 2 times: before the procedure and at 1 Y by clinical examination. The last was measured with the visual analogic scale (VAS 0-10 points) before the procedure and at 1 week (W), 1 month (M), 3 M, 6 M and 1 Y by interview. At 1 Y the patient global satisfaction towards the procedure was evaluated by asking if they would have undergone this treatment again. Data statistical analysis was performed with Wilcoxon test and Mann-Whitney test. Images for this section: Fig. 1: (A) The needle is inserted with plantar access; (B) superimposition of the plantar nerves drawing on the sole of the foot, the needle tip is directed towards the MN in the 2nd interspace; (C) plantar nerves drawing [modified from (4):p. 623]. CDN: common digital nerve, DN: digital nerve, PN: plantar nerve. Page 3 of 11

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5 Fig. 2: Longitudinal ultrasound scan in correspondence with the third metatarsal space before (A) and during (B) the ablation: in (B) the neuroma becomes hyperechoic starting from the periphery. Page 5 of 11

6 Fig. 3: Transversal ultrasound scan in correspondence with the second metatarsal space before (A) and after (B) the radiofrequency ablation: the neuroma is hyperecoic at the end of the procedure. Page 6 of 11

7 Results Among the 19 neuromas (in 18 patients), 12 were found in the third intermetatarsal space and the other 7 were in the second intermetatarsal space (ratio 1.7:1). On US, the mean size of the measured neuromas was 5,36 mm (range 3-8 mm): in 9 feet (47%) the neuroma measured less than 5 mm and in 10 feet (53%) it measured more than 5 mm. Prior to treatment, all patients had serious pain on daily activities (pre-procedure VAS average 8.8, range 8-10) and compromised global foot function (pre-procedure AOFAS score average 48.16, range 33-69). During the first ablation all patients experienced intense pain; mild or no pain was referred on the second and third ablations. There were no complications during or after the procedure. Post RFA there was a statistically significant reduction in VAS during the first 3 months for all the patients (VAS average 1 W 5.21, p <.0001; 1 M 3.58, p<.002; 3 M 2.21, p<.003) with a subsequent plateau (6 M 2.58, 1 Y 2.32) ( Table 1 on page 7 and Fig. 4 on page 8 ). We looked for different results according to the size of the lesion measured on the US-scan (neuroma # 5 mm as group A or > 5 mm as group B)(8). At 1 W we observed a statistically significant better pain reduction in neuromas bigger than 5 mm (average VAS group A: 4.10 vs group B: 6.44, p<.02). Instead at 1 Y we noticed a better VAS score for neuromas smaller than 5 mm (VAS group A: 3.30 vs group B: 1.22, p<.09). At 1 Y the global foot function was statistically significant improved (average AOFAS score pre-rfa vs post-rfa 82.68, p<.0001) and 17 out of 19 neuromas (89%) had a satisfactory outcome. Images for this section: Page 7 of 11

8 Table 1: Results of VAS (0-10 points) before the procedure [pre-rfa] and at 1 week [1W], 1 month [1M], 3 months [3M], 6 months [6M] and 1 year [1Y]. Results of AOFAS forefoot score (0-100 points) before the procedure [pre-rfa] and at 1 year [1Y]. SD = standard deviation. Page 8 of 11

9 Fig. 4: The graph shows the reduction of pain at different times (1W, 1M, 3 M, 6 M and 1 Y) from the procedure. At 1 Y there is a tendency to recurrence of pain for neuromas bigger than 5 mm [> 5 line] compared to the smaller ones [< 5 line]. Page 9 of 11

10 Conclusion The data confirms for the first time the effectiveness of RFA for Morton's neuroma even in long term follow-up, with reduction of pain and improvement of the global foot function at 1 year after the procedure. The dimension of MNs seems to correlate with the outcome: the effectiveness of the RFA appears to be long-lasting for lesions smaller than 5 mm and there is a mild tendency to recurrence of pain in patients with MN larger than 5 mm. The technique uses plantar access and controls the needle tip position by sensory nerve stimulation as well as with ultrasound imaging, which also permits the surveillance of the lesion for the entire procedure. The procedure was secure, repeatable, and well tolerated: the majority of patients was satisfied and would undergo the procedure again. References 1. Graham CE, Johnson KA, Ilstrup DM. The intermetatarsal nerve: a microscopic evaluation. Foot Ankle Nov;2(3): Lassmann G. Morton's toe: clinical, light and electron microscopic investigations in 133 cases. Clin Orthop Aug;(142): Mann RA, Reynolds JC. Interdigital neuroma--a critical clinical analysis. Foot Ankle Feb;3(4): Coughlin MJ, Saltzman CL, Anderson RB. Mann's surgery of the foot and ankle. Ninth edition. Philadelphia, PA: Elsevier Saunders; 2014: Genon MP, Chin TY, Bedi HS, Blackney MC. Radio-frequency ablation for the treatment of Morton's neuroma. ANZ J Surg Sep;80(9): Chuter GSJ, Chua YP, Connell DA, Blackney MC. Ultrasound-guided radiofrequency ablation in the management of interdigital (Morton's) neuroma. Skeletal Radiol Jan;42(1): Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int Jul;15(7): Makki D, Haddad BZ, Mahmood Z, Shahid MS, Pathak S, Garnham I. Efficacy of corticosteroid injection versus size of plantar interdigital neuroma. Foot Ankle Int Sep;33(9): Page 10 of 11

11 Personal Information R. Mazzetti. University of Turin Hospital Città della Salute e della Scienza di Torino Page 11 of 11