Artéria mediana persistente e síndrome do túnel do carpo: Um estudo retrospectivo

Resumo Objetivo  Este é um estudo retrospectivo acerca da persistência da artéria mediana associada à síndrome do túnel do carpo (STC). Métodos  Este é um estudo retrospectivo da persistência da artéria mediana e STC. Os critérios de exclusão foram pacientes que não apresentavam artéria mediana persistente, aqueles que eram diabéticos ou reumatoides e os que decidiram não realizar a cirurgia. Apenas 25 pacientes foram elegíveis para este estudo retrospectivo. Resultados  A trombose da artéria mediana apresentou diferenças estatísticas considerando as variáveis sexo ( p  = 0,009), achados eletroneuromiográficos ( p  = 0,021), profissão ( p  = 0,066) e “duração total desde o início dos sintomas” ( p  = 0,055). A atrofia da musculatura tenar não apresentou diferenças estatísticas à comparação das variáveis. O nervo mediano bífido apresentou diferenças estatísticas em comparação aos testes provocativos ( p  = 0,013), frequência dos sintomas ( p  = 0,001) e idade ( p  = 0,028). Conclusão  Embora incomum, a persistência da artéria mediana deve ser considerada um diagnóstico diferencial da STC. A ultrassonografia é um método confiável para prever a anatomia do túnel do carpo. O início tardio e os sintomas podem influenciar a trombose arterial e piorar os sintomas. Abstract Objective  This study presents a retrospective study of persistent median artery associated with carpal tunnel syndrome (CTS). Methods  A retrospective study of the persistent median artery and CTS. Exclusion criteria were patients who did not present persistent median artery, those who were diabetic, or had rheumatoid diseases, and those who decided not to do the surgery. Only 25 patients were eligible for this retrospective study. Results  Median artery thrombosis had statistical differences considering the variables sex ( p  = 0.009), electroneuromyography findings ( p  = 0.021), profession ( p  = 0.066), and “total duration since the beginning of the symptoms” ( p  = 0.055). Thenar muscle atrophy had no statistical differences when compared to the variables. Bifid median nerve had statistical differences when compared to provocative tests ( p  = 0.013), frequency of symptoms ( p  = 0.001), and age ( p  = 0.028). Conclusion  Although uncommon, the persistent median artery should be considered a differential diagnosis for CTS. Ultrasonography is a reliable method to predict carpal tunnel anatomy. Late onset and symptoms could influence artery thrombosis and worsen the symptoms.


Introduction
Carpal tunnel syndrome (CTS) is a compressive disorder of the median nerve at the wrist level that affects approximately 4% of the general population, being the most common compressive neuropathy of the upper limb. 1,24][5] The median nerve progresses to the wrist level adjacent to nine tendons in the carpal tunnel, an inextensible osteofibrous canal.Patients complain of pain and paresthesia, worst at night.Weakness of thenar muscles is common and could evolute to thenar muscle atrophy (TMA). 5,6everal causes could compress the median nerve, either idiopathic or secondary. 6Among the secondary causes are endocrine-metabolic alterations (pregnan, diabetes), fractures and dislocations, tumors (ganglions, lipomas), systemic causes (rheumatoid), anatomical variations and persistence of the Median artery. 2,6,7he persistent Median artery is present in approximately 0.9 to 16% of the population. 7It is present in the embryonic period, being the dominant bloodstream in the embryonic hand, helping the development of the arteries of the upper limb and involuting from the 8th week of pregnancy.][9] The persistence of the Median artery in the fetal period could contribute to the development of the superficial palmar arch, which may be more exuberant than usual.When traveling through the carpal tunnel together with the Median nerve, although rare, it can trigger carpal tunnel syndrome. 10edian artery persistence can occur in two patterns: antebrachial and palmar. 11In the first, the Median artery ends as a muscular branch, not reaching the wrist with no pathogenesis.In the second type, the Median artery extends to the palmar territory, crossing the carpal tunnel, sometimes participating in the formation of the superficial palmar arch, and becoming a possible cause for carpal tunnel syndrome. 2,8,11,12

Methods
This study was approved by our institutional review board (CAAE-45542621.2.0000.5440).The patient and his family were informed that data from the case would be submitted for publication and gave their consent.
A retrospective study reviewed the medical records of patients who presented carpal tunnel syndrome associated with persistent median artery submitted to decompression surgery in a tertiary hospital.
There were 1,276 patients with carpal tunnel syndrome submitted to decompression between 2012 to 2020.Inclusion criteria were patients who presented persistent Median artery and carpal tunnel syndrome from 2012 to 2020, being 38 patients.Exclusion criteria were patients who did not present the persistent median artery, diabetic, rheumatoid diseases and those who decided not to do the surgery.Only 25 patients were eligible for this retrospective study.We used the data present in the medical records and imaging exams, such as ultrasound and MRI (►Fig. 1).
The mean age was 41 years (ranging from 18-73 years), and there were 17 females and 6 males.Furthermore, 24 patients were righthanded.The profession and variables of the participants are presented in ►Table 1.The provocative tests (Durkan and Phalen) were present in all the patients during physical evaluation.However, 11 patients present numbness during physical evaluation.There were 5 patients who reported intermittent symptoms, and 20 were continuous.All the patients complained about weakness; however, only four patients presented with TMA.The preoperative protocol includes ultrasonography (Doppler) to measure the

Palavras-chave
► artéria mediana ► nervo mediano ► neuropatia mediana ► síndrome do túnel carpal carpal tunnel and the median nerve.Electroneuromyography (EMG) was performed for all patients.The patients were submitted to surgical decompression of the median nerve at the wrist level, 17 on the right wrist and eight on the left wrist (►Fig. 2).There were 19 patients who presented with bifid median nerve (BMN), as observed in the ultrasonography.There were seven TMAs during surgical evaluation.No complications were reported (infection, wound complications, recurrence).The mean follow-up was 76.5 months (ranging from 33 to 216), with no recurrence reported yet.
The Student t-test and Chi-squared tests were used to analyze the variables.A two-tailed p-value of less than 0.05 was considered statistically significant.All analyses were performed using the Statistical Package Social Sciences (SPSS, IBM Corp., Armonk, NY, USA) for Os X, version 22.0.
There were statistical differences between the variables "total duration since the beginning of the symptoms" (ANOVA: p ¼ 0.055, Levene test: 0.003) and MAT.There were no statistical differences in the variable age (ANOVA: p ¼ 0.197, Levene: 0.461) and MAT.
The results of the variables are shown in ►Table 2. All the ultrasonography studies and the operative findings (BMN and persistent median artery) were statistically relevant (Chi-square: p ¼ 0.001).

Discussion
The CTS is a well-known disease, but the association between the persistent median artery remains a source for discussion.The other studies and researchers have few patients, and there were Rev Bras Ortop © 2024.The Author(s).Rev Bras Ortop © 2024.The Author(s).

Sex
Persistent Median Artery Felix et al.
no prospective studies.Cadaveric studies help to understand the median artery's epidemiology and anatomic distribution, but the CTS is still hard to understand.There were no reports about how this condition behaved and how many persistent median arteries would evolve as such, becoming the persistent median artery CTS (PMA-CTS).Diabetic and rheumatoid patients were excluded because diabetic mononeuropathy and rheumatoid features could overlap the PMA-CTS.We know that most of the studies explain intermittent symptoms of PMA-CTS, but there is no established cutoff in the current literature.Considering our data reports, all the patients recorded intermittent nocturnal pain and numbness, worsening during summer or hot days and alleviating in the winter or cold days.Furthermore, 18 patients complained of worsening symptoms after 2 years.At this time, the intermittent symptoms become continuous.The other 7 patients searched for medical care after 3 years because of the continuous symptoms.At the first evaluation, all the patients presented a provocative positive test (Durkan and Phalen), but only 7 presented numbness during the day of the physical evaluation before testing.
Regarding the association between the persistent median artery and CTS, Barfred et al. 13 observed two distinct groups.The first group had typical symptoms, with insidious onset and chronic evolution, and presented as a surgical finding with a patent persistent median artery.The second group had symptoms of abrupt onset, with intense pain and paresthesia, presenting with a persistent MAT during the surgical procedure. 2,13t is essential to be aware of persistent MAT as a differential diagnosis for CTS since it usually progresses with EMG without alterations, considering that the nature of aggression to the nerve, axonal degenerations will not be present initially. 1,2,7][16][17] Some studies suggest that sudden onset of neurological symptoms due to compression of the median nerve at the level of the carpal tunnel, the sensation of cold and edema must be treated as clinical warnings and should lead to the performance of ultrasound with Doppler color of the arteries of the upper limbs. 14A computed tomography (CT) angiography can show more details with higher precision, defining the dominance of the median artery in hand perfusion, thus helping better decision-making.Furthermore, some studies advocate ultrasound evaluation before the release of the carpal tunnel to evaluate the local anatomy and to observe the presence of persistent median artery.][17][18][19] Gassner et al. 16 described a classification of the persistent median artery and the median nerve as normal, high division, and BMN.This division correlates the localization of the persistent median artery to the median nerve in the carpal tunnel (ulnar, radial, or intermediary).][21] A persistent median artery was associated with the BMN in 76% of the cases, compared to other studies that presented about 63% of correlation. 12,18Regarding the mean diameter of this artery, it was similar to that found by the same author, being 1.4 mm (0.9-4.0) against 1.3 mm (0.8-2.5 mm). 3,7espite the results presented, our study has few cases, and they were not submitted to decompression in the same period since the beginning of the symptoms.Given this, the statistical difference presented should be carefully analyzed.Other reports explain that arterial thrombosis worsens the symptoms.In cases of late-onset symptoms or late search for medical care, EMG abnormalities in the provocative tests are expected.The late search for medical care and the variables TMA, frequency of symptoms, and arterial thrombosis could be misunderstood.We believe that the relationship between age and total duration of the symptoms is due to CTS being uncommon in younger patients.When a younger patient complains of CTS symptoms, ultrasonography is advised.Thus, surgical intervention could be performed earlier, helping patients have fewer symptoms and complications.

Conclusion
We conclude that, although uncommon, the persistent median artery should be considered a differential diagnosis for CTS.Ultrasonography is a reliable method to predict carpal tunnel anatomy.The late onset of symptoms could influence artery thrombosis and worsen the symptoms.

Financial Support
The author(s) received no financial support for the research, authorship, and/or publication of this article.