This was an observational, prospective, case-control study conducted in Libreville from January 2016 to January 2018 inclusive. It involved 72 people divided into four groups. The first group consisted of 19 women who had to undergo myoma surgery using the elastic tourniquet (M + G +), while the second consisted of those who would benefit from a myomectomy without using the elastic tourniquet (M + G −). The third group included women with unoperated myoma (M + G0), while healthy women formed the fourth group (control, M0G0).

This work has been done according to Helsinki's ethical recommendations on the use of living things [41] . Informed consent was obtained from women. In addition, they have been assured of the confidentiality of the data collected. In addition, we obtained prior authorizations from those responsible for the structures in which we conducted this study.

The socio-demographic and clinical parameters of the study population are summarized in Table 1. The mean age of the M + G + patients was 34.78 ± 5.28 years old. Taking into account other groups of women, it was 37.78 ± 6.04 years for M + G −, 37.25 ± 7.54 years and 35.83 ± 6.15 years for M + G0’s and M0G0 respectively. The mean duration of myomectomy without tourniquet was 108.93 ± 85.795 min, compared to 105.72 ± 34.55 with tourniquet (p = 0.060). That of the tourniquet was 51.56 ± 14.12 [20 - 82 min]. Six women had more than 10 myomas in the M + G + group, compared to one in the M + G − group. Mean myoma size was 23 mm in M + G + patients compared to 18.26 mm in M + G − patients.

The average plasma concentration of CPK was 57.208 U/l in M0G0, compared to 71.64 U/l in M + G0 (p = 0.118). GPX was 2.306 pg/ml in M0G0, compared with 3.567 pg/ml in M + G0 (p = 0.0001). Mean plasma concentration of Ca²⁺ was 2.879 mmol/l in M0G0 against 3.00 mmol/l in M + G0 (p = 0.683). That of K⁺ was 3.705 mmol/l in M0G0’s, compared with 3.934 mmol/l in M + G0’s (p = 0.219) (Table 2).

The average plasma concentration of CPK was 57.21 U/l in M0G0, whereas it was 71.64 U/l in M + G +, before the tourniquet (p = 0.118), 95.67 U/l during (p = 0.001), and 135.443 U/l after emergence (p < 0.00001).

The mean plasma concentration of GPX was 2.306 μg/ml in M0G0’s. In M + G +, it was 3.567 pg/ml before tourniquet (p = 0.0001), 3.645 pg/ml during (p < 0.00001) and 3.694 pg/ml after release (p < 0.00001).

Mean serum calcium was 2.879 mmol/l in M0G0’s. Conversely, in M + G +, it was 3.00 mmol/l before tourniquet (p = 0.683), 3.64 mmol/l during (p = 0.035), and 3.892 after emergence (p = 0.012). In M + G +, mean serum potassium was 3.934 mmol/l before tourniquet placement (p = 0.219), 4.757 mmol during (p = 0.0006), and 5.322 mmol/l after tourniquet emergence (p < 0.00001), versus 3.705 mmol/l in M0G0 (Table 3).

In M + G −, the mean plasma CPK concentration was 59.354 U/l before surgery, 91.270 U/l during (p = 0.005), and 137.776 U/l after (p = 0.0005), compared with 57.21 U/l at M0G0.

The mean plasma concentration of GPX in M + G − was 3.255 μg/ml before surgery, 3.413 μg/ml during (p = 0.008) and 3.632 μg/ml after (p = 0.001). In M0G0, it was 2.306 pg/ml.

*p = 0.0001.

*p < 0.00001; **p = 0.0001; ***p = 0.0006.

Mean serum calcium was 2.879 mmol/l in M0G0, whereas it was in M 0+ G − before surgery 2.525 mmol/l (p = 0.109), while 3.068 mmol/l (p = 0.515) and after 3.148 (p = 0.396).

Mean serum potassium was 3.705 mmol/l in M0G0’s. In M + G −, it was 3.788 mmol/l before surgery (p = 0.557), 4.257 mmol/l during (p = 0.023) and 5.075 mmol/l after (p = 0.0012) (Table 4).

In the basal state, plasma CPK concentrations were 71.4 U/l in M + G +, compared to 59.354 U/l in M + G − (p = 0.084). 95.665 U/l in M + G +, compared to 91.270 U/l in M + G −, five minutes after myoma ablation (p = 0.462). They were 134.443 U/L fifteen minutes after the tourniquet release in M + G +, compared with 137.776 U/l in M + G −, fifteen minutes after uterine suture (p = 0.732).

*p = 0.0005; **p = 0.0012.

The average plasma concentrations of GPX were 3.567 μg/ml in M + G + versus 3.255 μg/ml in M + G − before surgery (p = 0.321). During surgery, they were 3.645 μg/ml at M + G +, versus 3.413 pg/ml in M + G − (p = 0.317). Fifteen minutes after emergence of ET in M + G +, these levels were 3.694 U/l, as against 3.632 U/l, fifteen minutes after the uterine suture in M + G − (p = 0.001).

Plasma Ca²⁺ concentrations were 3 mmol/l in M + G +, compared to 2.525 mmol/l in M + G − (p = 0.171), prior to surgery. During surgery, they were 3.642 mmol/l in M + G +, against 3.060 mmol/l in M + G − (p = 0.185). Fifteen minutes after the uterine suture, they were 3.892 mmol/l in the M + G +, versus 3.413 mmol/l in M + G − (p = 0.073).

Mean kaliemias were 3.148 mmol/l in M + G +, compared to 3.148 mmol/l in M + G −, before surgery (p = 0.285). During surgery, they were 4.575 mmol/l in M + G +, versus 4.257 mmol/l in M + G − (p = 0.010). After surgery, these concentrations were 5.322 mmol/l in M + G +, compared to 5.075 mmol/l in M + G − respectively (p = 0.101) (Table 5).

At the end of our study, no statistically significant difference was found between the plasma concentrations of ischemia markers (CPK, K +, Ca²⁺⁾ found in controls (M0G0) and those of women with unoperated myomas (M + G0). These results show that the plasma levels of ischemia markers obtained in women with non-operated myoma (M + G −) are not different from those of healthy women (M0G0).

Our data thus suggest that the myomas in themselves probably do not have systemic detectable proischemic activity, despite intense in situ proliferative activity, previously observed by Cibiera, Guo, Zheng, et al. [52] [53] [54] [55] . However, concerning the plasma level of GPX (marker of reperfusion), there was a significant variation between the two groups. In this case, it could be an asymptomatic necrosis of myomas in a previous period, but recent in our study. Indeed, in the literature, high levels of GPX have been observed in women with myomas, and this elevation would be dependent on the hormonal cycle [45] [46] [48] . A positive correlation existed between the GPX level and the ratio estrogen/progesterone at the plasma level. In contrast, there was a negative correlation between FSH concentrations and intra-myopathic GPX levels. According to the authors, the systemic cyclic hormonal variations within the myomatous tissue would be at the origin of oxidative stress and could partly explain the fact that this pathology is uncommon in postmenopausal women [45] [46] .

Thus, despite the intense local proliferative and oxidative activity of uterine myomas, our data allow us to consider the concentrations of IR markers obtained in M0G0’s as a control or reference concentration [42] [43] [50] .

A statistically significant difference was found between the plasma concentrations of the markers of ischemia (CPK, K +) and reperfusion (GPX) of the controls (M0G0) and those measured during the ablation of the myomas and after the suture of uterus without tourniquet in M + G − women. CPK concentrations of M + G − women were less than once normal during uterine suture (p = 0.001), and more than 2 times normal 15 minutes after (p = 0.0005). Those of GPX were 1.58 times the control value during uterine suture (p = 0.008), and 1.6 times that of controls, 15 minutes later (p = 0.001). The relationship between I/R and surgical intervention on the one hand, and IR without removal of myoma without tourniquet on the other hand, have been widely described [9] [28] [29] [35] [36] [39] [47] [49] [56] [57] Indeed, with respect to uterine surgery without tourniquet use, regardless of the technique (laparoscopy/laparotomy), it has been shown to be responsible for systemic I/R phenomena, due to surgical act [47] [49] [56] [57] . In this case, the elevation of the markers observed in M + G − could be explained by incisions and parietal and uterine sutures. In the same way, another explanation would be rather related to the ablation of the myomas proper.

A study by Farimani et al., which examined the expression of markers of oxidative stress after myomectomy, found elevated levels of GPX3 and glycodelin in the myometrium, up to 3 months after surgery, in women who received a myomectomy without tourniquet. According to the latter, the myomectomy would lead to an expression of GPX, so oxidative stress phenomena in relation to the implantation zone of the egg. This mechanism could be involved in the infertility observed in these patients [48] .

As a result, compared with plasma reference levels (control values), plasma concentrations of IR markers are elevated in M + G − during the surgical period. Thus, the classical surgical procedure (incision, then uterine and parietal suture), constantly practiced during this type of intervention would be the main cause of this increase [47] [49] [56] [57] . However, despite the fact that this is difficult to demonstrate in practice, the intra uterine expression of GPX evoked by Farimani et al. during the ablation of myomas, taken in isolation, could promote a secondary elevation of plasma GPX levels [48] .

Compared with M0G0 women, the plasma concentrations of I/R markers were not significantly different from those found in M + G + women before surgery (p = 0.118). Conversely, those obtained during the pose and fifteen minutes after the lifting of the elastic tourniquet were not only high compared to the control values, but were still significantly higher after the lifting of the elastic tourniquet with respect to the exposure period. These data assume that surgeries requiring any temporary arrest of the arterial circulatory system, such as tourniquet use, lead to ischemia reperfusion and apoptosis [2] [7] [12] [13] [14] [15] [16] [29] [30] [31] [32] [34] [58] . This IR would itself be responsible for an increase in intracellular calcium mediated by the Ca²⁺ complex and the 1,4,5 Inositol triphophate1/Ryanodine 1 (IP3R1/RYR1) receptors [34] . the difference in concentration noted between the duration of tourniquet application and that of relapse corroborates the results of several studies [12] [13] [14] [15] [16] [29] [30] [31] [32] , and thus suggests greater muscle suffering during reperfusion [3] [4] [6] [13] [14] [15] [16] [32] [32] [35] [36] . However, our results do not allow us to specify whether this elevation is related exclusively to the use of the withers [7] [27] [31] [33] [34] [58] , removal of myomas [48] , and/or incision followed by uterine and parietal suture [47] [49] [56] [57] .

To compare the plasma concentrations of GPX, CPK, Ca²⁺, K⁺ collected before, during and fifteen minutes after the emergence of the elastic tourniquet in patients with tournaments of tourniquet-shaped myoma (M + G +), compared to patients with myocardial surgery without tourniquet (M + G −).

Before surgery, the plasma concentrations of I/R markers of women operated without tourniquet-free myoma (M + G −) were not significantly different from those operated for myoma using tourniquet (M + G −) This result suggests that myomas are probably not in themselves responsible for systemic I/R phenomena, despite prooxidative and inflammatory intra-myomatous activity described by contemporary studies [45] [46] [52] [53] [54] . Thus, Snezana and et al., as well as Santulli and et al., noted overexpression of prooxidant species in myomatous tissue correlated with hormonal variation during the menstrual cycle in women still sexually active [45] [46] .

In the same way, during the entire duration of the elastic tourniquet in women M + G + (time corresponding to the ligation of the arteries, the uterine incision and the removal of the myomas in the subjects M + G +), the plasma levels markers obtained were not different from those of patients operated for myomas without tourniquet (time corresponding to uterine incision and ablation of myomas without tourniquet in M + G −), but were nevertheless higher than the control concentrations (M0G0). Several explanations of this result are possible.

With respect to GPX and CPK plasma assay techniques, although those used in the present investigation have few limitations, their system-level sensitivities to IR are limited. is not absolute [42] [43] [50] . To do this, a plasma assay of markers correlated with an immunohistochemical study would be more interesting [48] [49] .

Another explanation is the existence of a network of vascular supply at the uterine level and around the fibroid [59] . This important vascular network could improve circulation during arterial ligation, thus decreasing the production and accumulation of free radicals and other molecules from tissue pain. According to several authors, this type of vascularization could explain the tolerance of the uterus with respect to ischemia and paradoxically the destruction of certain myomas observed after myomectomies by arterial ligation [29] - [39] [58] [59] [60] .

A third reason would be related to the actual surgical procedure. Thus, the elevation of markers noted in women who had undergone a myomectomy (M + G +/M + G −) would be mainly due to the surgical act, that is to say to the tissue damage linked to the incision parietal and uterine, as well as ablation of myomas. Several studies have shown that abdominal surgery is responsible for tissue and systemic ischemia and inflammation [47] [49] [56] [57] . Oksuzoglu and et al., comparing plasma levels of CPK and interleukin-6 (IL6) in different types of uterine surgery, found higher levels of these markers during uterine abdominal versus laparoscopic surgery [57] . Al-Khyatt and et al., for their part, observed ischemia phenomena during laparoscopic intestinal surgery [56] .

At the end of this investigation, the average tourniquet duration was 51.56 ± 14.12 minutes, with extremes of 30 and 88 minutes. Apart from myocardial ischemia, which is usually established in less than an hour [1] [2] [8] , in the majority of studies concerning the phenomena of tissue ischemia in general, and more specifically that of origin these lesions occur downstream and beyond the 2^nd hour during a circulatory interruption upstream [7] [12] [13] [14] [15] [16] [32] [34] [37] [39] [51] . In other words, the duration of tourniquet less than 90 minutes could also be a factor explaining the absence of significant variation in plasma marker levels between groups of women M + G + and M + G −, despite their elevation within each of the two groups. Indeed, the phenomena of ischemia were observed both in animals than in humans, only during periods of arterial occlusion exceeding 1h30 minutes. In orthopedics, in animals, inflating times greater than 2 hours would be responsible for sometimes irreversible muscle damage, despite the duration of reperfusion of more than 3 hours [12] [13] [14] [15] . One of the mechanisms involved is a progressive decrease in super oxide dismutase with mitochondrial dysfunction. In humans, according to Omar [16] , Oragui [15] , and Van der Spuy and et al. [51] , tourniquet exposure times exceeding 2 hours are responsible for systemic ischemic phenomena. In the opinion of the same authors, the plasma marker levels of IR.

On a human scale, these lesions appear at the same time and would have repercussions on the myometrium, the myoma, the ovarian function, as well as the long-term fertility [27] [28] [29] [30] [31] [35] [36] [39] [40] . In addition, the human uterus is more tolerant to cold ischemia than the warm one [36] . In the case of myomectomies performed in women, a Nigerian [22] and a Bulgarian [61] study respectively noted a correlation between the post-operative complications of abdominal myomectomies and the exposure times of elastic tourniquet greater than 3 hours. With respect to myomectomies, Banus and al, during myomectomies performed by arterial embolization, also found elevated plasma levels of ischemia markers at the end of the 3^rd hour after embolization [39] . Studies found muscle ischemia lesions on average beyond the 2^nd hour. It is this situation that is likely to advocate tourniquet delay or any interruption of arterial circulation not exceeding 120 minutes during this type of surgery [18] [20] [23] [24] [59] .

During our investigation, more than half of myoma operated women (M + G + and M + G −) had more than 10 myomas, ranging in size from 18.26 to 23.11 mm.

The number, but also the size and locations of the myomas could also be elements that can influence the systemic expression of ischemia generated in situ by the effect of the elastic tourniquet. According to some authors, these factors considerably modify the duration of myomectomies because of their impact on the ablation of the myomas themselves [17] [22] [24] [26] [40] [59] [61] . That the placement of GE not more than 90 minutes is not likely to be the cause of the increased biomarkers of ischemia observed in M + G + women at the systemic level. In this case, despite other factors such as the characteristics of the myoma and the system of uterine vascular supply that can influence the kinetics of these markers, this result suggests that this elevation is exclusively secondary to the actual surgical activity. .

After the release of the tourniquet (the time corresponding to the end of myoma ablation and suture of the uterus in M + G +, and at the end of the uterine suture in M + G −), plasma concentrations markers of ischemia (calcium, CPK and potassium) and reperfusion (GPX) were higher compared to control values (M0G0). However, comparing the levels of markers obtained in M + G + to those of M + G −, it appears that those of ischemia did not vary between the two groups, whereas those of GPX were significantly different (p = 0.001). Compared to the basal state (control value), these results show that the plasma concentrations of ischemia markers are increased in women operated on myomas (M + G + and M + G −), but without however, differ between these two groups. Physiopathologically corresponding tourniquet emergence from IR to the reperfusion phase, the low specificity of serum calcium, potassium, and CPK with respect to reperfusion could be an explanation for this result [1] - [8] [10] [13] [15] [50] [51] [58] . According to Yang and et al., under hypoxic conditions, such as those encountered during ischemia by uterine arterial occlusion, calcium would be involved in cellular apoptosis phenomena via IP3R1/RYR1 receptors [34] .

Similarly, the existence of uterine vascular replacement, associated with tourniquet durations not exceeding 1h30 minutes during our investigation, would also be another reason [59] . Continuous or even partial perfusion, would favor a progressive decrease in the plasma concentration of the markers before the recirculation process secondary to the lifting of the tourniquet [1] - [7] [12] [13] [14] [32] [51] [58] [62] .

Finally, these data support the idea that surgery is a process responsible for ischemic phenomena [3] [47] [49] [56] [57] . Moreover, in comparison with the control values, they assume that the variation noted is not due to the relaxation of the withers, but rather to the ischemia related to the surgical incisions.

There was a statistically significant difference, despite a slight variation in GPX plasma concentrations between M + G + and M + G − (3.694 versus 3.632, p = 0.001), after the lifting of the elastic tourniquet (time corresponding to the end of the removal of myomas and suture of the uterus in M + G +, and at the end of uterine suture in M + G −). The sensitivity of GPX to reperfusion is well established [42] [43] [50] , the incomplete uterine ischemia caused by the existence of the vascular supply [59] strongly solicited during uterine surgeries. Performed under arterial occlusion, could explain this result once again [29] [30] [31] [35] [36] . According to Byron and et al. [14] , the relaxation of the tourniquet performed on the lower limb of a rat is immediately accompanied by an overproduction of the biomarkers of the IR. In this case, we can say that there is a phenomenon of reperfusion during the myomectomies under tourniquet, but it is of lesser degree, probably due to complex anastomotic intrauterine and peri-myomatous vasculature previously evoked by Nassif and et al. [59] .

To a lesser degree, the tourniquetation times chosen in this study, together with the particular vascularization of the uterus, may also justify the data obtained. In the literature, most of the work dealing with this aspect of the subject is of an experimental nature.

Thus, in macaques, Kisu and et al. [32] , as well as Adachi and et al. [62] , noted high levels of reperfusion markers only at the end of the 1^st and 3^rd hours respectively after the arterial occlusion was removed. Tsompos and al. Looking for markers of muscle pain after half an hour in rats, had obtained similar data [32] . In humans, a study by Banu et al, in women with myomas uterine patients, had elevated plasma concentrations of markers of ischemia and inflammation only 24 hours after embolization of the uterine arterial occlusion, but did not specify the surgical or emboligenic origin of this increase [39] . As a result, this result shows that the lifting of the elastic tourniquet is not the cause of the increase in plasma I/R markers found in M + G + women. Moreover, he suggests that the variations of the markers observed during the various surgical stages within each of the two groups of women operated (M + G +/M + G −) compared to those of the controls (M0G0) are due essentially to the surgical procedure, ie the intensity of the lesion process linked to the operative procedure (parietal and uterine incision, ablation of the myomas, parietal suture, then uterine) which depends in part on the operating time.