Anatomical Observation And Surgical Treatment Of Morton’s Neuroma

Objective:To study the anatomy of the digital nerve in the metatarsal space and the distribution of its branches,and the anatomical characteristics and relative position of the digital nerve and deep transverse metatarsal ligament(DTML)were summarized.To study the therapeutic effect of Morton’s neurectomy and Transection of the deep metatarsal transverse ligament for Morton’s neuroma,and to analyze the relationship between the size of Morton’s neuroma and the duration of the disease and the therapeutic effect of the operation.Combined with the results of anatomical and clinical studies,the pathological characteristics and treatment of Morton’s neuroma were explored.Methods:There are 6 formalin-soaked foot specimens from 3 cadaver specimens,the digital nerve and DTML of which were dissected from the plantarof.Vernier calipers were used to measure the vertical distance AB between point A at the distal edge of DTML and point B at the proximal edge of DTML.The branch distribution of the digital nerve were observed,point C at the site with no obvious branch,measure the distance between B and C.A 3 cm incision was made at Metatarsal web from the doesal side,cutting off the DTML,maximum proximally separating digital nerve.point D was made at the most proximally position,measuring the distance from DTML proximal edge B and D.The branch of the digital nerve was dissected proximally,and the digital nerve was dissected at point D to observe whether the stump could be retracted to the intrinsic foot muscle.Retrospective analysis was made on the cases of patients with Morton’s tumor who underwent surgical treatment in the hand surgery department of China-Japan Friendship Hospital of Jilin University from January 2016 to December 2020.And the characteristics of the patients were summarized,including gender,age,site of disease,course of disease,imaging results and lesion size.According to the surgical methods,they were divided into the Morton’s neurectomy group and Transection of the deep metatarsal transverse ligament for Morton’s neuroma group.During the operation,the size of Morton’s tumor and its relationship with DTML were observed and measured,and the length of the neuroma resected in the neuroma resection group was measured.The mean follow-up time was 29 months.The patients’ satisfaction with the operation was investigated,and the recurrence of pain numbness was understood.The pain was scored according to the VAS pain scoring standard,and the maximum walking distance tolerated by the patients was recorded,as well as whether there was any restriction on wearing shoes.Combined with the above indexes,the surgical efficacy of each group was evaluated and compared.Results:Anatomy shows that the digital nerve runs in the metatarsal space and has many small branches.The closer it is to the metatarsal region,the more nerve branches there are.The average length of AB and BC was11.06 mm and 3.06 cm respectively,while the average maximum length of BD from the proximal edge of DTML to the proximal end of the digital nerve that could be resected through the dorsal incision was 1.94 cm.After severing the digital nerve,the stump can be retracted into the internal muscle of the foot.There were 12 patients,4 males and 8 females,with a mean age of 58 years.There were 18 cases of Morton’s neuroma in total,among which 6 patients had two cases of Morton’s neuroma at the same time,and the rest were single cases.Among the multiple cases,2 patients had homolateral foot and the rest had bilateral foot.There were 11 cases in the left foot,7 cases in the right foot,3 cases in the first metatarsal space,7 cases in the second metatarsal space,8 cases in the third metatarsal space.The main symptoms were pain in 14 cases,numbness in 2 cases,pain with numbness in 2 cases.The duration of which was> 5 years in 2patients,≥2 years < 5 years in 6 patients,and < 2 years in 4patients.Preoperative color Doppler examination of tumor diameter showed that 1 case had the largest tumor diameter ≥5mm,9 cases had the largest tumor diameter ≥3 and less than 5mm,and 8 cases had the largest tumor diameter < 3mm.There were 5 Morton’s neuroma in 4 patients in the neurotomy group,and 13 Morton’s neuroma in 8 patients in the DTML neurolysis group.The size of Morton’s neuroma observed during the operation was consistent with the results of ultrasound.There were 15 cases of Morton’s neuroma formed by DTML entrapment of the digital nerve.The length of the excised nerve was 2 ～ 2.5cm.Postoperative satisfaction survey: very satisfactory: 4 cases of Morton’s neuroma in 2patients;Satisfactory: 10 cases of Morton’s neuroma in 7 patients;Dissatisfaction: Morton tumors were found in 4 of the 3 patients.There were 9 cases of Morton’s neuroma in 7 patients who still had pain symptoms after surgery,including 3patients in the neuroma resection group and 4 cases of Morton’s neuroma(average VAS pain score of4.38).Among the 4 patients in the DTML neurolysis group,and 5 cases of Morton’s neuroma(mean VAS score of 6.2).There were 5 cases of Morton’s neuroma in 4 patients with numbness symptoms,including 2cases of Morton’s neuroma in the neuroma resection group and 3 cases of Morton’s neuroma in the DTML incision nerve lysis group,respectively.Postoperative symptoms of all patients were significantly relieved compared with preoperative symptoms,and there were no incision infection,scar related complications,foot deformity and gait changes.Three patients had recurrent symptoms at 2 weeks,2 months,and 3 years postoperatively,all of whom were in the Transection of DTML nerve lysis group.Conclusion:The size of Morton’s tumor and the surgical method are important factors affecting the prognosis.For the treatment of Morton’s neuroma,dorsal approach neuroma resection should be performed by completely resecting the nerve branches of the common digital nerve as proximally as posible,and at least 2cm of the proximal digital nerve should be removed.