- Email: [email protected]
Ultrasound guided radiofrequency ablation of Morton’s neuroma: A substitute for surgery
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
Contents lists available at ScienceDirect
The Egyptian Journal of Radiology and Nuclear Medicine journal homepage: www.elsevier.com/locate/ejrnm
Original Article
Ultrasound guided radiofrequency ablation of Morton’s neuroma: A substitute for surgery Ahmed M. Bassiouny Department of Radiodiagnosis and Interventional Radiology, Ain Shams University Hospitals, Egypt
A R T I C LE I N FO
A B S T R A C T
Keywords: Morton's neuroma Radiofrequency
Objectives: To assess the efficacy of radiofrequency ablation of Morton's neuroma (MN) as a substitute to surgery, in patients not responding to conservative treatment. Methods: 15 patients, who performed radiofrequency ablation (RFA) of Morton's neuroma between November 2015 and December 2016, were submitted to follow up to assess the response to therapy over a period of 6 months by assessment of pain relief through visual analogue scale (VAS) scale from 1 to 10 from least to severe pain. Results: All of the 15 patients suffered from intense pain during their normal daily activity prior to RF ablation, pretreatment VAS average was 7. Follow up of the patients was done after 1 week, 1 month, 3 months and 6 months. After RF ablation, pain disappeared in 9 cases (60%), 3 had mild pain (20%), 2 moderate pain (13.3%) and 1 with severe pain (6.6%) and proceeded to surgery. Complete resolution of pain was encountered in the patients with mild and moderate pain with conservative or second session of RFA. Conclusion: Radiofrequency ablation of Morton's neuroma, is an effective technique in treatment of symptomatic patient's after failure of conservative treatment and prior to surgical intervention.
1. Introduction
2. Materials and methods
Morton's neuroma (MN) is a painful condition affecting the common digital nerve of the foot. It is a nerve entrapment condition under the transverse metatarsal ligament [1,2]. This condition is aggravated by the wearing of tight shoes or by using compressive stockings. The pain is usually described by the patient as: acute, severe, radiating to the toes, leg sometimes with strong burning sensation. Local paresthesia of the 3rd and 4th toes is very common. The pain is commonly felt in the third intermetatarsal space, less often in the second, rarely in the fourth and extremely rarely in the first intermetatarsal space [3]. The incidence of Morton’s neuromas is common in females at their fifth decade and it affects the digital nerve of the third inter digital space more than in the second space with ratio 2:1 [1,4]. Radiofrequency ablation is a practical and effective solution in patients not responding to conservative treatment. Above 88% of the affected patients had complete resolution of the pain without further surgical intervention or any other procedures [5].
15 patients were reviewed with 15 MN all were females with mean age 42 years. Patients were diagnosed clinically to have MN, confirmation of diagnosis was made by ultrasound and/or MRI (Fig. 1 ), (Fig. 3A–C). None of the 15 patients responded to conservative treatment for at least 3 months and were candidates for surgical excision. RFA of the neuromas was their last option prior to surgery. 2.1. Technique The study was approved by our institution review board. A written consent was taken from the patients with detailed steps of the procedure and its possible complications. First ultrasound was done to region of complain to confirm the diagnosis of Morton's neuroma, and assess the access for RFA. The patient is in supine position with sterile field prepared. Under ultrasound-guidance, a sterile 5 cm long radiofrequency needle was inserted, through either plantar or dorsal aspect access, inside the neuroma (Fig. 2).
Peer review under responsibility of The Egyptian Society of Radiology and Nuclear Medicine. E-mail address: [email protected]. https://doi.org/10.1016/j.ejrnm.2017.11.008 Received 27 July 2017; Accepted 22 November 2017 0378-603X/ copyright 2018 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Please cite this article as: Bassiouny, A.M., The Egyptian Journal of Radiology and Nuclear Medicine (2018), https://doi.org/10.1016/j.ejrnm.2017.11.008
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
result from an increase in local temperature at the site of application around the electrode to the point of disruption of the tissue protein chains, which subsequently destroys the peripheral nerve endings, and the myelin sheaths, blocking only nociceptive input [6,7]. Other authors thought that pain regression after RF ablation results are not from the actual destruction of nerve tissue, but are from powerful electric fields induced by voltage fluctuations in the area of lesion [8,9]. Patients are allowed to leave with bandage at operative site after observation for 30 min. Rest at home for 24–48 h and wearing comfortable not tight shoes is advised before returning to normal life style. Patient can take NSAIDS for postoperative pain if necessary. Follow up ultrasound is done at 1, 3 and 6 months post ablation, MRI was done in selected cases according to their complain or pain score. 2.2. Statistical analysis Analysis of data was done by IBM computer using SPSS (statistical program for social science version 12).
• Description of quantitative variables as mean and range. • Description of qualitative variables as number and percentage. 3. Results Of the 15 patients, all suffered from pain during their normal daily activity prior to RFA, pretreatment VAS average was 7 (Table 1), pain duration was variable ranging from 3 months up to 8 months, conservative treatment was given for 3 months. In our study patient’s not responding conservative treatment for at least 3 months are candidates for RFA. 13 MN were found in the 3rd web space (86.6%) while only 2 were found in the 2nd web space (13.3%). Follow up of the patients was done after 1 week, 1 month, 3 months and 6 months. After RF ablation pain disappeared in 9 cases (60%), 3 had mild pain (20%), 2 moderate pain (13.3%) and 1 with severe pain (6.6%) proceeded to surgery (Table 2). Patients with mild and moderate pain were treated by bupivacaine/ triamcinolone, resolved pain was encountered in the three cases of mild pain and one of the moderate pain cases, the second patient with moderate pain was offered another setting of RFA, that totally resolved the pain (Table 3).
Fig. 1. Figures (A) and (B) show ultrasound appearance of Morton's neuroma between the 3rd and 4th metatarsal bones.
4. Discussion In patients with symptomatic Morton's neuroma not responding to conservative treatment, RFA is considered a second option prior to surgical solution. In our study, none of our patients had complications, thus supporting the safety and efficacy of the procedure. Open neurectomy complications are minimal, however as any surgery there are risks, as hematoma, stump neuroma and abscess formation. Surgical endoscopic decompression of the neuroma (EDIN-Barrett technique), requires at least 6 months to evaluate success [10]. Previous study showed that failure to respond to conservative measures radiofrequency treatment is considered a more beneficial procedure than open neurectomy. It causes destruction of the peripheral nerve endings and myelin sheath at site of maximum tenderness [11].
Fig. 2. Radiofrequency needle in Morton's neuroma.
Proper position of the needle tip is confirmed by ultrasound and sensory stimulation, where the patient feels pain similar to that of her symptom, then local anesthesia using 1 cc of 2% Xylocaine was applied. RFA was done using our machine Neurotherm NT1100 (Neurotherm, USA), guided by superficial ultrasound probe 7.5 MHz (My Lab 40, Esaote, ITALY) 3 times along the course of the neuroma with temperature up to 75–80 °C each time for about 60 s. Pain relief after local radiofrequency nerve ablation is thought to
2
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
Fig. 3. T1WI Pre ablation (A) T1WI post ablation after 1 month with regression in size, (B) Fat suppression images postcontrast more regression in size after 6 months with only post therapeutic enhancement pattern (C).
In literature radiofrequency ablation is a fast technique that can be done in ambulatory conditions without sutures and it gives the similar results of positive outcomes as surgical procedures but without serious complications. The procedure has minimal or almost no side effects or disability [13].
In our study after RFA 60% of the patients had no pain, 20% had mild pain and 13.3% had moderate pain which was satisfactory for them compared to the initial pain, only one case had an unsatisfactory outcome. Finny et al. found that the procedure is satisfactory in 68% of cases and non-satisfactory in 32% [12].
Table 2 Response to pain after RFA of MN.
Table 1 Visual analogue scale for pain (VAS). 0
1
2
No complain No pain
Annoying Mild pain
3
4
Response to pain % 5
Uncomfortable Moderate pain
6
7
8
9
10 No pain Mild Moderate Severe
Horrible/agonizing Severe pain
3
60 (n = 9) 20 (n = 3) 13.3 (n = 2) 6.6 (n = 1)
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
References
Table 3 Pain scoring after RFA of MN 1, 3 and 6 months follow up. Patients numbers and age
Pretreatment pain score
Pain score at 1 month posttreatment
Pain score at 3 months posttreatment
Pain score at 6 months posttreatment, with either adjuvant conservative or 2nd RFA
1(45 years) 2(46) 3(44) 4(46) 5(43) 6(50) 7(46) 8(40) 9(47) 10(46) 11(42) 12(52) 13(43) 14(46) 15(43)
8 9 7 5 4 8 9 6 8 6 7 9 5 4 6
4 6 3 2 1 3 8 3 5 3 3 5 2 1 4
3 0 2 0 0 3 7 0 4 0 0 5 0 0 0
0 0 0 0 0 0 7 0 0 0 0 0 0 0 0
[1] Graham CE, Johnson KA, Ilstrup DM. The intermetatarsal nerve: a microscopic evaluation. Foot Ankle 1981 Nov;2(3):150–2. [2] Lassmann G. Morton's toe: clinical, light and electron microscopic investigations in 133 cases. Clin Orthop 1979 Aug;142:73–84. [3] Frascarelli M, Urciolo M, Monachino P, Baleanu M, Favilli G. La Sindrome di Morton. (Valutazione Elet- tromiografica). Chirurgia Del Piede 1998;22(3):151–5. [4] Mann RA, Reynolds JC. Interdigital neuroma–a critical clinical analysis. Foot Ankle 1983 Feb;3(4):238–43. [5] Paolo R, Roberto A, Mihai BP. Radiofrequency thermos-ablation of Morton's neuroma: Valid Minimally Invasive Treatment Procedure in Patients Resistant to conservative Treatment. Open J Orthopedics 2013;3(08):325. [6] Cosman Jr. ER, Cosman Sr. ER. Electric and thermal field effects in tissue around radiofrequency electrodes. Pain Med 2005;6(6):405–24. http://dx.doi.org/10. 1111/j.1526-4637.2005.00076.x. [7] Todorov L. Pulsed radiofrequency of the sural nerve for the treatment of chronic ankle pain. Pain Physician 2011;14(3):301–4. [8] Zundert J, Raj P, Erdine S, van Kleef M. Application of radiofrequency treatment in practical pain management: state of the art. Pain Practice 2002;2(3):269–78. [9] Van Zundert J, de Louw AJ, Joosten EA, Kes- sels AG, Honig W, Dederen PJ, et al. Pulsed and con- tinuous radiofrequency current adjacent to the cervical dorsal root ganglion of the rat induces late cellular activity in the dorsal horn. Anesthesiology 2005;102(1):125–31. [10] Barrett SL, Rabat E, Buitrago M, Rascon VP, Applegate PD. Endoscopic Decompression of Intermeta- tarsal Nerve (EDIN) for the treatment of Morton’s Entrapment-multicenter retrospective review. Open J Orthopedics 2012;2(2):19–24. [11] Cione JA, Cozzarelli J, Mullen CJ. A retrospective study of radiofrequency thermal lesioning for the treatment of neuritis of the medial calcaneal nerve and it's terminal branches in chronic heel pain. J Foot Ankle Surg 2008;48:142–7. [12] Finny W, Wirner S, Catanzariti F. Treatment of Morton's neuroma using percutaneous electrocoagulation. J Am Podiatr Med Assoc 1989;79:615–8. [13] Ronconi P, Arcioni R, Baleanu Petre M. Radiofrequency thermo-ablation of Morton’s neuroma: a valid minimally invasive treatment procedure in patients resistant to conservative treatment. Open J Orthopedics 2013;2013(3):325–30.
In conclusion, RFA is a safe, curative, minor invasive procedure in case of MN that can substitute surgery in most cases. Conflict of interest No conflict of interest to be declared.
4
Contents lists available at ScienceDirect
The Egyptian Journal of Radiology and Nuclear Medicine journal homepage: www.elsevier.com/locate/ejrnm
Original Article
Ultrasound guided radiofrequency ablation of Morton’s neuroma: A substitute for surgery Ahmed M. Bassiouny Department of Radiodiagnosis and Interventional Radiology, Ain Shams University Hospitals, Egypt
A R T I C LE I N FO
A B S T R A C T
Keywords: Morton's neuroma Radiofrequency
Objectives: To assess the efficacy of radiofrequency ablation of Morton's neuroma (MN) as a substitute to surgery, in patients not responding to conservative treatment. Methods: 15 patients, who performed radiofrequency ablation (RFA) of Morton's neuroma between November 2015 and December 2016, were submitted to follow up to assess the response to therapy over a period of 6 months by assessment of pain relief through visual analogue scale (VAS) scale from 1 to 10 from least to severe pain. Results: All of the 15 patients suffered from intense pain during their normal daily activity prior to RF ablation, pretreatment VAS average was 7. Follow up of the patients was done after 1 week, 1 month, 3 months and 6 months. After RF ablation, pain disappeared in 9 cases (60%), 3 had mild pain (20%), 2 moderate pain (13.3%) and 1 with severe pain (6.6%) and proceeded to surgery. Complete resolution of pain was encountered in the patients with mild and moderate pain with conservative or second session of RFA. Conclusion: Radiofrequency ablation of Morton's neuroma, is an effective technique in treatment of symptomatic patient's after failure of conservative treatment and prior to surgical intervention.
1. Introduction
2. Materials and methods
Morton's neuroma (MN) is a painful condition affecting the common digital nerve of the foot. It is a nerve entrapment condition under the transverse metatarsal ligament [1,2]. This condition is aggravated by the wearing of tight shoes or by using compressive stockings. The pain is usually described by the patient as: acute, severe, radiating to the toes, leg sometimes with strong burning sensation. Local paresthesia of the 3rd and 4th toes is very common. The pain is commonly felt in the third intermetatarsal space, less often in the second, rarely in the fourth and extremely rarely in the first intermetatarsal space [3]. The incidence of Morton’s neuromas is common in females at their fifth decade and it affects the digital nerve of the third inter digital space more than in the second space with ratio 2:1 [1,4]. Radiofrequency ablation is a practical and effective solution in patients not responding to conservative treatment. Above 88% of the affected patients had complete resolution of the pain without further surgical intervention or any other procedures [5].
15 patients were reviewed with 15 MN all were females with mean age 42 years. Patients were diagnosed clinically to have MN, confirmation of diagnosis was made by ultrasound and/or MRI (Fig. 1 ), (Fig. 3A–C). None of the 15 patients responded to conservative treatment for at least 3 months and were candidates for surgical excision. RFA of the neuromas was their last option prior to surgery. 2.1. Technique The study was approved by our institution review board. A written consent was taken from the patients with detailed steps of the procedure and its possible complications. First ultrasound was done to region of complain to confirm the diagnosis of Morton's neuroma, and assess the access for RFA. The patient is in supine position with sterile field prepared. Under ultrasound-guidance, a sterile 5 cm long radiofrequency needle was inserted, through either plantar or dorsal aspect access, inside the neuroma (Fig. 2).
Peer review under responsibility of The Egyptian Society of Radiology and Nuclear Medicine. E-mail address: [email protected]. https://doi.org/10.1016/j.ejrnm.2017.11.008 Received 27 July 2017; Accepted 22 November 2017 0378-603X/ copyright 2018 The Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Please cite this article as: Bassiouny, A.M., The Egyptian Journal of Radiology and Nuclear Medicine (2018), https://doi.org/10.1016/j.ejrnm.2017.11.008
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
result from an increase in local temperature at the site of application around the electrode to the point of disruption of the tissue protein chains, which subsequently destroys the peripheral nerve endings, and the myelin sheaths, blocking only nociceptive input [6,7]. Other authors thought that pain regression after RF ablation results are not from the actual destruction of nerve tissue, but are from powerful electric fields induced by voltage fluctuations in the area of lesion [8,9]. Patients are allowed to leave with bandage at operative site after observation for 30 min. Rest at home for 24–48 h and wearing comfortable not tight shoes is advised before returning to normal life style. Patient can take NSAIDS for postoperative pain if necessary. Follow up ultrasound is done at 1, 3 and 6 months post ablation, MRI was done in selected cases according to their complain or pain score. 2.2. Statistical analysis Analysis of data was done by IBM computer using SPSS (statistical program for social science version 12).
• Description of quantitative variables as mean and range. • Description of qualitative variables as number and percentage. 3. Results Of the 15 patients, all suffered from pain during their normal daily activity prior to RFA, pretreatment VAS average was 7 (Table 1), pain duration was variable ranging from 3 months up to 8 months, conservative treatment was given for 3 months. In our study patient’s not responding conservative treatment for at least 3 months are candidates for RFA. 13 MN were found in the 3rd web space (86.6%) while only 2 were found in the 2nd web space (13.3%). Follow up of the patients was done after 1 week, 1 month, 3 months and 6 months. After RF ablation pain disappeared in 9 cases (60%), 3 had mild pain (20%), 2 moderate pain (13.3%) and 1 with severe pain (6.6%) proceeded to surgery (Table 2). Patients with mild and moderate pain were treated by bupivacaine/ triamcinolone, resolved pain was encountered in the three cases of mild pain and one of the moderate pain cases, the second patient with moderate pain was offered another setting of RFA, that totally resolved the pain (Table 3).
Fig. 1. Figures (A) and (B) show ultrasound appearance of Morton's neuroma between the 3rd and 4th metatarsal bones.
4. Discussion In patients with symptomatic Morton's neuroma not responding to conservative treatment, RFA is considered a second option prior to surgical solution. In our study, none of our patients had complications, thus supporting the safety and efficacy of the procedure. Open neurectomy complications are minimal, however as any surgery there are risks, as hematoma, stump neuroma and abscess formation. Surgical endoscopic decompression of the neuroma (EDIN-Barrett technique), requires at least 6 months to evaluate success [10]. Previous study showed that failure to respond to conservative measures radiofrequency treatment is considered a more beneficial procedure than open neurectomy. It causes destruction of the peripheral nerve endings and myelin sheath at site of maximum tenderness [11].
Fig. 2. Radiofrequency needle in Morton's neuroma.
Proper position of the needle tip is confirmed by ultrasound and sensory stimulation, where the patient feels pain similar to that of her symptom, then local anesthesia using 1 cc of 2% Xylocaine was applied. RFA was done using our machine Neurotherm NT1100 (Neurotherm, USA), guided by superficial ultrasound probe 7.5 MHz (My Lab 40, Esaote, ITALY) 3 times along the course of the neuroma with temperature up to 75–80 °C each time for about 60 s. Pain relief after local radiofrequency nerve ablation is thought to
2
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
Fig. 3. T1WI Pre ablation (A) T1WI post ablation after 1 month with regression in size, (B) Fat suppression images postcontrast more regression in size after 6 months with only post therapeutic enhancement pattern (C).
In literature radiofrequency ablation is a fast technique that can be done in ambulatory conditions without sutures and it gives the similar results of positive outcomes as surgical procedures but without serious complications. The procedure has minimal or almost no side effects or disability [13].
In our study after RFA 60% of the patients had no pain, 20% had mild pain and 13.3% had moderate pain which was satisfactory for them compared to the initial pain, only one case had an unsatisfactory outcome. Finny et al. found that the procedure is satisfactory in 68% of cases and non-satisfactory in 32% [12].
Table 2 Response to pain after RFA of MN.
Table 1 Visual analogue scale for pain (VAS). 0
1
2
No complain No pain
Annoying Mild pain
3
4
Response to pain % 5
Uncomfortable Moderate pain
6
7
8
9
10 No pain Mild Moderate Severe
Horrible/agonizing Severe pain
3
60 (n = 9) 20 (n = 3) 13.3 (n = 2) 6.6 (n = 1)
The Egyptian Journal of Radiology and Nuclear Medicine xxx (xxxx) xxx–xxx
A.M. Bassiouny
References
Table 3 Pain scoring after RFA of MN 1, 3 and 6 months follow up. Patients numbers and age
Pretreatment pain score
Pain score at 1 month posttreatment
Pain score at 3 months posttreatment
Pain score at 6 months posttreatment, with either adjuvant conservative or 2nd RFA
1(45 years) 2(46) 3(44) 4(46) 5(43) 6(50) 7(46) 8(40) 9(47) 10(46) 11(42) 12(52) 13(43) 14(46) 15(43)
8 9 7 5 4 8 9 6 8 6 7 9 5 4 6
4 6 3 2 1 3 8 3 5 3 3 5 2 1 4
3 0 2 0 0 3 7 0 4 0 0 5 0 0 0
0 0 0 0 0 0 7 0 0 0 0 0 0 0 0
[1] Graham CE, Johnson KA, Ilstrup DM. The intermetatarsal nerve: a microscopic evaluation. Foot Ankle 1981 Nov;2(3):150–2. [2] Lassmann G. Morton's toe: clinical, light and electron microscopic investigations in 133 cases. Clin Orthop 1979 Aug;142:73–84. [3] Frascarelli M, Urciolo M, Monachino P, Baleanu M, Favilli G. La Sindrome di Morton. (Valutazione Elet- tromiografica). Chirurgia Del Piede 1998;22(3):151–5. [4] Mann RA, Reynolds JC. Interdigital neuroma–a critical clinical analysis. Foot Ankle 1983 Feb;3(4):238–43. [5] Paolo R, Roberto A, Mihai BP. Radiofrequency thermos-ablation of Morton's neuroma: Valid Minimally Invasive Treatment Procedure in Patients Resistant to conservative Treatment. Open J Orthopedics 2013;3(08):325. [6] Cosman Jr. ER, Cosman Sr. ER. Electric and thermal field effects in tissue around radiofrequency electrodes. Pain Med 2005;6(6):405–24. http://dx.doi.org/10. 1111/j.1526-4637.2005.00076.x. [7] Todorov L. Pulsed radiofrequency of the sural nerve for the treatment of chronic ankle pain. Pain Physician 2011;14(3):301–4. [8] Zundert J, Raj P, Erdine S, van Kleef M. Application of radiofrequency treatment in practical pain management: state of the art. Pain Practice 2002;2(3):269–78. [9] Van Zundert J, de Louw AJ, Joosten EA, Kes- sels AG, Honig W, Dederen PJ, et al. Pulsed and con- tinuous radiofrequency current adjacent to the cervical dorsal root ganglion of the rat induces late cellular activity in the dorsal horn. Anesthesiology 2005;102(1):125–31. [10] Barrett SL, Rabat E, Buitrago M, Rascon VP, Applegate PD. Endoscopic Decompression of Intermeta- tarsal Nerve (EDIN) for the treatment of Morton’s Entrapment-multicenter retrospective review. Open J Orthopedics 2012;2(2):19–24. [11] Cione JA, Cozzarelli J, Mullen CJ. A retrospective study of radiofrequency thermal lesioning for the treatment of neuritis of the medial calcaneal nerve and it's terminal branches in chronic heel pain. J Foot Ankle Surg 2008;48:142–7. [12] Finny W, Wirner S, Catanzariti F. Treatment of Morton's neuroma using percutaneous electrocoagulation. J Am Podiatr Med Assoc 1989;79:615–8. [13] Ronconi P, Arcioni R, Baleanu Petre M. Radiofrequency thermo-ablation of Morton’s neuroma: a valid minimally invasive treatment procedure in patients resistant to conservative treatment. Open J Orthopedics 2013;2013(3):325–30.
In conclusion, RFA is a safe, curative, minor invasive procedure in case of MN that can substitute surgery in most cases. Conflict of interest No conflict of interest to be declared.
4