surgery is not free from significant complications , despite advancement in surgical techniques and in perioperative care .
one of the major complications , particularly for breast and soft tissues surgery , is post - operative bleeding which represents a critical and , in some cases , lethal risk factor .
moreover , post - operative bleeding after breast surgery causes a severe discomfort to the patient , entailing the need for surgical re - intervention and sometimes blood transfusions .
another frequent complication of breast surgery is seroma , which often requires numerous accesses for outpatient drainage , finally resulting in a delay of adjuvant therapy administration and a significant psychological burden .
a recent study conducted in the united states has extracted from the 2011 nationwide inpatient sample the hospital discharge rates for primary diagnosis of breast cancer and has selectively identified discharges with post - operative bleeding .
results showed that even if only 2.5% of the discharges had bleeding complications and eventually needed re - operation , globally , bleeding complications extended the length of stay by 1.3 days while increasing hospital costs by $ 5495 per admission . moreover , even higher health costs and patients discomfort are associated with the treatment of chronic or refractory seroma .
the risk of blood loss or seroma could be limited by identifying and then correcting potential triggers , but although this topic has been extensively studied , both hemorrhage and seroma are still largely reported .
homeopathy could provide remedies based on compounds with anti - hemorrhagic and anti - inflammatory properties , but their use in diluted homeopathic solutions has been poorly investigated [ 6 - 9 ] . indeed , some homeopathic remedies have been already evaluated in various surgical settings , however showing controversial effects [ 10 - 17 ] .
arnica montana is a plant belonging to the compositae family and it grows in east and central europe . in particular , its anti - inflammatory action is linked to the lactone helenalin that seems to be involved in the inhibition of the pro - inflammatory transcription factor nuclear factor kappa b ( nf- ) [ 19 - 27 ] .
a. montana has been recently evaluated in several surgical settings such as esthetic and orthopedic surgeries , but currently , no single study is available in literature on the effects of this homeopathic remedy in breast cancer surgery . in the present study , a homeopathic preparation of a. montana 1000 korsakovian dilution ( 1000 k )
was administered preoperatively and postoperatively in a placebo - controlled , double - blind clinical trial to patients undergoing unilateral total mastectomy , with or without reconstruction , to evaluate any favorable or adverse effect on post - operative blood and seroma collection from surgical drains .
this randomized , double - blind , placebo - controlled study was carried out between 2012 and 2014 in a single university hospital department ( breast unit ,  luigi sacco  university hospital , milan , italy ) .
fifty - three women affected by breast cancer who were candidates for unilateral total mastectomy , with or without reconstruction , were enrolled in the study .
the study was authorized by the ethical committee of the same university hospital ( trial register number : 93/2011 , approved by ethical committee on february 15 , 2012 ) and was conducted in accordance with the international conference on harmonization of good clinical practice guidelines .
women were included in the study if they were : ( a ) aged between 20 and 75 years ; ( b ) hospitalized for unilateral total mastectomy , with or without reconstruction ; ( c ) and subjected to standard treatment , as described in the  concomitant therapies  section . other variables , such as weight and breast size , were recorded and considered .
women were excluded from the study if they were : ( a ) receiving complex surgery such as breast reconstruction by transverse rectus abdominis or latissimus dorsi myocutaneous flaps , or in case of needed axillary dissection ; ( b ) admitted at the emergency department ; ( c ) receiving anticoagulants and antiplatelet treatments ; ( d ) affected by bleeding disorders ; ( e ) patients with liver pathologies or with concomitant severe general diseases ; ( f ) patients receiving drug therapy with aromatase inhibitors or anticancer therapies ; ( g ) patients with a history of stroke or of acute myocardial infarction , < 24 months before ; ( h ) patients diagnosed with other concurrent tumors ; ( i ) patients who had participated in other clinical trials in the 3 months prior to the study ; ( j ) and patients with values of prothrombin time ( pt ) , partial thromboplastin time ( ptt ) , and fibrinogen outside the normal range of the clinical site ( i.e. , 0.85 - 1.18 s for pt , 0.85 - 1.20 s for ptt , and 170 - 400 mg / dl for fibrinogen ) . the day before surgery ( day 0 ) , vital signs ( blood pressure , heart rate , and blood oxygen saturation ) were evaluated , along with any concomitant medication and any adverse event that could have occurred since the screening visit .
moreover , based on the results of blood tests , the eligibility of the patient was re - verified .
the enrolled patient was then assigned to a treatment group according to the randomization list .
randomization was created by the contract research organization ( cro ) opera s.r.l . and generated using the random function ( proc plan ) of sas ( version 9.4 ) software . at screening , each patient was assigned to a code composed of the identification number of the clinical site in two digits ( e.g. , 01 ) and the identification number of the patient to three digits ( e.g. , 001 - 002 - 003 ) .
the cro opera s.r.l held the key to the randomization list in a sealed envelope , which was not opened until the end of the study . the key was used only after freezing of the database and finalization of the statistical analyses .
the patients , according to the randomization list , received sublingually a dose of five drops of a. montana 1000 k 3 times a day , or placebo with identical times of administration , from 1 day before the surgery until the 4 day after the surgery ( in total 6 days ) . on the day of surgery ( day 1 ) , the previously assigned treatment was continued .
all the patients were operated by the same surgical team . during the operation , surgical drains with a caliber of 15 french ( equal to 5 mm in diameter ) were positioned .
surgeons did not know the allocation of patients in the treatment groups . from the end of surgery and for every 12 h ,
a control was carried out , the amount of blood and serum volumes collected through drainages was recorded , and for every 24 h , a blood test for the evaluation of the complete blood count ( cbc ) and the performance of coagulation factors was carried out . in the days following the surgery ( days 2 - 4 ) , the patients continued the previously assigned treatment .
vital signs , any concomitant medication , adverse event , and the presence of bruises or hematomas were monitored .
finally , patients were asked to provide an opinion on the perception of pain after surgery , using a visual analog scale ( vas ) .
day 5 concluded the study . on this day , the treatment previously assigned was continued , and the liquid collected by drains ( if still positioned ) was measured . if it was still not possible to remove the drainage , the amount of fluid drained was registered for the last time and , based on other parameters , the date of the possible discharge of the patient was indicatively anticipated .
conversely , if all parameters resulted in the normal range and drains were removed , the patient had the possibility to be discharged before the 5 day ; in this case , the patient was not prematurely withdrawn , but she was considered having correctly completed the study .
the principal endpoint of the study was the efficacy of a. montana versus placebo in reducing the post - operative blood loss and seroma production in patients undergoing unilateral total mastectomy , with or without reconstruction .
the secondary end points included the following : 
 duration of drainage , which was calculated from day 1 to the day of drainage removaltime to reach a collected volume below 10 mlself - evaluation of pain , measured by vas after surgerythe average time of hospitalization after surgery , which was measured in days following surgerythe presence of bruising and hematomas or breast swelling , measured both in terms of presence versus absence and of description or sizethe differences between the volume collected on day 1 and the volume collected in each of the following dayspossible adverse reactions to treatment . 
 
duration of drainage , which was calculated from day 1 to the day of drainage removal time to reach a collected volume below 10 ml self - evaluation of pain , measured by vas after surgery the average time of hospitalization after surgery , which was measured in days following surgery the presence of bruising and hematomas or breast swelling , measured both in terms of presence versus absence and of description or size the differences between the volume collected on day 1 and the volume collected in each of the following days possible adverse reactions to treatment .
the appropriate accrual hypothesized for the study was set to 60 patients , with a 1:1 ratio per treatment group ( a. montana 1000 k vs. placebo ) . considering a possible 10% dropout rate
, this sample size could allow us to have a final population of 53 women , presenting a mean blood and serum collection of 280 ml in the placebo group and of 200 ml in a. montana group ( sd 100 ml ) , considering adequate a statistical power equal to 80% .
finally , 53 women with breast cancer and candidate for unilateral total mastectomy , with or without reconstruction , were enrolled in the study .
a. montana 1000 k was in the form of drops in 30% hydro alcoholic solution , with sublingual absorption .
the 1000 k dilution is a very high homeopathic dilution produced according to the french pharmacopoeia , starting from a mother tincture ( complete plant extract ) which undergoes 1000 steps of successive dilution and shaking in a 30% water  alcohol solution .
the mother tincture of the product used in this study contained a minimum content of 0.04% of sesquiterpenes ( expressed as dihydrohelenanin tiglate ) . according to the korsakovian dilution method
, the same flask was used for the entire preparation : at each step , the flask was emptied of most of the liquid but not dried , and then immediately filled again with the solvent . because the residual volume after emptying the flask certainly can not be > 10% of the total used in each dilution , the 1000 k dilution is sufficiently high that it certainly does not contain toxic amounts of the plant .
the placebo drops were identical in appearance to the active drops , but included only 30% hydro alcoholic solution without any homeopathic dilution .
the studied homeopathic treatment and the placebo were manufactured and supplied in strictly identical packaging by laboratoires boiron s.r.l .
a standard treatment used in the management of surgical procedures was administered to all the patients enrolled in the study .
in particular , it was provided as follows : 
 antibiotic prophylaxis with cefazolin 2 g intravenous ( iv ) once;antithrombotic prophylaxis using low molecular weight heparin at a dose of 4000 iu 12 h before the surgery;analgesic therapy with paracetamol 1000 mg iv for every 6 h for the first 24 h and tramadol 100 mg iv , if needed . 
 
antibiotic prophylaxis with cefazolin 2 g intravenous ( iv ) once ; antithrombotic prophylaxis using low molecular weight heparin at a dose of 4000 iu 12 h before the surgery ; analgesic therapy with paracetamol 1000 mg iv for every 6 h for the first 24 h and tramadol 100 mg
morphine 20 mg in continuous infusion with antiemetic medication was administered for the first 48 h. interval data were described as the number , mean , and standard deviation ( sd ) .
the differences in the blood and serum volumes collected by the drainage between a. montana and placebo were evaluated with three linear regression models : 
 model 1 : includes the treatment;model 2 : includes the treatment and the volume collected on the day of the intervention;model 3 : includes the treatment , the volume collected on the day of surgery , and patient weight . 
 
model 1 : includes the treatment ; model 2 : includes the treatment and the volume collected on the day of the intervention ; model 3 : includes the treatment , the volume collected on the day of surgery , and patient weight .
methods of survival analysis ( kaplan  meier ) were used to evaluate the duration of drainage need and time to reach a collected volume below 10 ml .
this randomized , double - blind , placebo - controlled study was carried out between 2012 and 2014 in a single university hospital department ( breast unit ,  luigi sacco  university hospital , milan , italy ) .
fifty - three women affected by breast cancer who were candidates for unilateral total mastectomy , with or without reconstruction , were enrolled in the study .
the study was authorized by the ethical committee of the same university hospital ( trial register number : 93/2011 , approved by ethical committee on february 15 , 2012 ) and was conducted in accordance with the international conference on harmonization of good clinical practice guidelines .
women were included in the study if they were : ( a ) aged between 20 and 75 years ; ( b ) hospitalized for unilateral total mastectomy , with or without reconstruction ; ( c ) and subjected to standard treatment , as described in the  concomitant therapies  section . other variables , such as weight and breast size , were recorded and considered .
women were excluded from the study if they were : ( a ) receiving complex surgery such as breast reconstruction by transverse rectus abdominis or latissimus dorsi myocutaneous flaps , or in case of needed axillary dissection ; ( b ) admitted at the emergency department ; ( c ) receiving anticoagulants and antiplatelet treatments ; ( d ) affected by bleeding disorders ; ( e ) patients with liver pathologies or with concomitant severe general diseases ; ( f ) patients receiving drug therapy with aromatase inhibitors or anticancer therapies ; ( g ) patients with a history of stroke or of acute myocardial infarction , < 24 months before ; ( h ) patients diagnosed with other concurrent tumors ; ( i ) patients who had participated in other clinical trials in the 3 months prior to the study ; ( j ) and patients with values of prothrombin time ( pt ) , partial thromboplastin time ( ptt ) , and fibrinogen outside the normal range of the clinical site ( i.e. , 0.85 - 1.18 s for pt , 0.85 - 1.20 s for ptt , and 170 - 400 mg / dl for fibrinogen ) . the day before surgery ( day 0 ) , vital signs ( blood pressure , heart rate , and blood oxygen saturation ) were evaluated , along with any concomitant medication and any adverse event that could have occurred since the screening visit .
moreover , based on the results of blood tests , the eligibility of the patient was re - verified .
the enrolled patient was then assigned to a treatment group according to the randomization list .
randomization was created by the contract research organization ( cro ) opera s.r.l . and generated using the random function ( proc plan ) of sas ( version 9.4 ) software . at screening , each patient was assigned to a code composed of the identification number of the clinical site in two digits ( e.g. , 01 ) and the identification number of the patient to three digits ( e.g. , 001 - 002 - 003 ) .
the cro opera s.r.l held the key to the randomization list in a sealed envelope , which was not opened until the end of the study . the key was used only after freezing of the database and finalization of the statistical analyses .
the patients , according to the randomization list , received sublingually a dose of five drops of a. montana 1000 k 3 times a day , or placebo with identical times of administration , from 1 day before the surgery until the 4 day after the surgery ( in total 6 days ) . on the day of surgery ( day 1 ) , the previously assigned treatment was continued .
all the patients were operated by the same surgical team . during the operation , surgical drains with a caliber of 15 french ( equal to 5 mm in diameter ) were positioned .
surgeons did not know the allocation of patients in the treatment groups . from the end of surgery and for every 12 h ,
a control was carried out , the amount of blood and serum volumes collected through drainages was recorded , and for every 24 h , a blood test for the evaluation of the complete blood count ( cbc ) and the performance of coagulation factors was carried out . in the days following the surgery ( days 2 - 4 ) , the patients continued the previously assigned treatment .
vital signs , any concomitant medication , adverse event , and the presence of bruises or hematomas were monitored .
finally , patients were asked to provide an opinion on the perception of pain after surgery , using a visual analog scale ( vas ) .
day 5 concluded the study . on this day , the treatment previously assigned was continued , and the liquid collected by drains ( if still positioned ) was measured . if it was still not possible to remove the drainage , the amount of fluid drained was registered for the last time and , based on other parameters , the date of the possible discharge of the patient was indicatively anticipated .
conversely , if all parameters resulted in the normal range and drains were removed , the patient had the possibility to be discharged before the 5 day ; in this case , the patient was not prematurely withdrawn , but she was considered having correctly completed the study .
the principal endpoint of the study was the efficacy of a. montana versus placebo in reducing the post - operative blood loss and seroma production in patients undergoing unilateral total mastectomy , with or without reconstruction .
the secondary end points included the following : 
 duration of drainage , which was calculated from day 1 to the day of drainage removaltime to reach a collected volume below 10 mlself - evaluation of pain , measured by vas after surgerythe average time of hospitalization after surgery , which was measured in days following surgerythe presence of bruising and hematomas or breast swelling , measured both in terms of presence versus absence and of description or sizethe differences between the volume collected on day 1 and the volume collected in each of the following dayspossible adverse reactions to treatment . 
 
duration of drainage , which was calculated from day 1 to the day of drainage removal time to reach a collected volume below 10 ml self - evaluation of pain , measured by vas after surgery the average time of hospitalization after surgery , which was measured in days following surgery the presence of bruising and hematomas or breast swelling , measured both in terms of presence versus absence and of description or size the differences between the volume collected on day 1 and the volume collected in each of the following days possible adverse reactions to treatment .
the appropriate accrual hypothesized for the study was set to 60 patients , with a 1:1 ratio per treatment group ( a. montana 1000 k vs. placebo ) . considering a possible 10% dropout rate
, this sample size could allow us to have a final population of 53 women , presenting a mean blood and serum collection of 280 ml in the placebo group and of 200 ml in a. montana group ( sd 100 ml ) , considering adequate a statistical power equal to 80% .
finally , 53 women with breast cancer and candidate for unilateral total mastectomy , with or without reconstruction , were enrolled in the study .
a. montana 1000 k was in the form of drops in 30% hydro alcoholic solution , with sublingual absorption .
the 1000 k dilution is a very high homeopathic dilution produced according to the french pharmacopoeia , starting from a mother tincture ( complete plant extract ) which undergoes 1000 steps of successive dilution and shaking in a 30% water
the mother tincture of the product used in this study contained a minimum content of 0.04% of sesquiterpenes ( expressed as dihydrohelenanin tiglate ) . according to the korsakovian dilution method
, the same flask was used for the entire preparation : at each step , the flask was emptied of most of the liquid but not dried , and then immediately filled again with the solvent . because the residual volume after emptying the flask certainly can not be > 10% of the total used in each dilution , the 1000 k dilution is sufficiently high that it certainly does not contain toxic amounts of the plant .
the placebo drops were identical in appearance to the active drops , but included only 30% hydro alcoholic solution without any homeopathic dilution .
the studied homeopathic treatment and the placebo were manufactured and supplied in strictly identical packaging by laboratoires boiron s.r.l .
a standard treatment used in the management of surgical procedures was administered to all the patients enrolled in the study .
in particular , it was provided as follows : 
 antibiotic prophylaxis with cefazolin 2 g intravenous ( iv ) once;antithrombotic prophylaxis using low molecular weight heparin at a dose of 4000 iu 12 h before the surgery;analgesic therapy with paracetamol 1000 mg iv for every 6 h for the first 24 h and tramadol 100 mg iv , if needed . 
 
antibiotic prophylaxis with cefazolin 2 g intravenous ( iv ) once ; antithrombotic prophylaxis using low molecular weight heparin at a dose of 4000 iu 12 h before the surgery ; analgesic therapy with paracetamol 1000 mg iv for every 6 h for the first 24 h and tramadol 100 mg iv , if needed . for patients undergoing reconstruction ,
morphine 20 mg in continuous infusion with antiemetic medication was administered for the first 48 h.
interval data were described as the number , mean , and standard deviation ( sd ) .
the differences in the blood and serum volumes collected by the drainage between a. montana and placebo were evaluated with three linear regression models : 
 model 1 : includes the treatment;model 2 : includes the treatment and the volume collected on the day of the intervention;model 3 : includes the treatment , the volume collected on the day of surgery , and patient weight . 
 
model 1 : includes the treatment ; model 2 : includes the treatment and the volume collected on the day of the intervention ; model 3 : includes the treatment , the volume collected on the day of surgery , and patient weight .
methods of survival analysis ( kaplan  meier ) were used to evaluate the duration of drainage need and time to reach a collected volume below 10 ml .
the 53 women enrolled in the study ( 26 in the a. montana group and 27 in the placebo group ) were all included in the intention - to - treat ( itt ) population , defined as all patients who took at least one dose of a. montana 1000 k or placebo .
the per - protocol ( pp ) population included all women of the itt dataset , except those women violating the protocol .
in particular , in the a. montana group , three patients were excluded ( two had pt , ptt , and fibrinogen altered values , and one patient received axillary dissection ) . in the placebo group , seven patients were excluded ( five had pt , ptt , and fibrinogen altered values , and two were on aromatase inhibitor or anticoagulant therapy introduced after enrollment ) .
baseline characteristics of the itt population blood and serum collected by drainages dramatically increased between day 1 and day 2 and then decreased in both treatment groups [ figure 1 ] . in the pp dataset , the collected volumes were higher in placebo group , but in the itt dataset , the difference was less noticeable [ figure 1a ] . in the pp dataset ,
the differences between the volume collected on day 1 and the volume collected in each of the following days revealed a difference steadily lower in the a. montana group compared to placebo [ figure 1b ] .
these differences were statistically significantly different between the two treatment groups on day 2 , both in the univariate model ( p = 0.034 ) and in the model including treatment and collected volume ( p = 0.033 ) , and on day 3 , only in the latter model ( p = 0.0223 ) adjusted for weight and volume to the day of surgery .
the difference between the two treatments was not statistically significant on days 4 and 5 .
globally , a lower mean volume of blood and serum collected by drainage was observed in a. montana group compared to placebo ( in pp analysis : 334.35 vs. 428.75 ml , p = 0.11 ) [ tables 2 and 3 ] .
a statistically significant difference was shown in regression model 3 applied on pp dataset , when the estimates were also adjusted for the volume collected from the drainage on day 1 and the weight of the patient [ table 4 ] .
changes in volume collected by drainage from day 1 to each following day per treatment : ( a ) intention - to - treat population and ( b ) per - protocol population ; *
p < 0.05 mean daily volume and total volume in the two treatment groups for the itt dataset mean daily volume and total volume in the two treatment groups for the pp dataset estimates of the mean difference in total volume collected by drainage during the study between the two treatment groups ( arnica  placebo ) by dataset during the 5 days of the study , the drainage was removed in 36 patients , equally distributed in the two groups .
the analysis of time of drain removal revealed no difference between the two groups of patients both in the itt dataset ( log - rank test p = 0.7287 ) and in the pp dataset ( log - rank test p = 0.8653 ) , although in a. montana group , drainage was apparently removed earlier [ figure 2a ] .
the analysis of the time up to collected volume below 10 ml neither revealed difference between the two treatments in the itt analysis ( log - rank test p = 0.8653 ) nor in the pp analysis ( log - rank test p = 0.6138 ) , but showing a better performance of the patients treated with a. montana in the latter [ figure 2b ] .
duration of drainage ( a ) and time to drainage volume below 10 ml ( b ) per treatment ( intention - to - treat and per - protocol datasets ) the presence of bruising and hematomas or breast swelling did not differ significantly by treatment group , p = 0.67 and p = 0.57 , respectively .
even the perception of pain , measured by vas , showed no statistically significant differences between the two treatment groups ( p > 0.05 ) .
all the recorded adverse events were not severe ( e.g. , rush , headache , nausea ) , not correlated with the a. montana treatment , and completely recovered at the end of the study .
moreover , they were equally distributed between the two groups : five patients experienced at least an adverse event in the a. montana group versus four in the placebo group .
in this study , which to our knowledge is the first to test the effect of a. montana in breast cancer surgery , we have measured the efficacy of the homeopathic treatment versus placebo in reducing the post - operative bleeding and seroma production in patients subjected to total mastectomy .
the difference in the volume of blood and serum collected by drainages between the group of women treated with a. montana and those treated with placebo was statistically significant in the pp dataset , but only in the model which included , in addition to the type of treatment , the volume collected on the day of surgery , and the weight of the patient .
thus , we determine that these two additional variables have a considerable effect on the efficacy of the treatment , and further studies are needed to investigate their specific contributions . in general , the other data obtained , such as a slightly earlier removal of the drainage and a faster reduction in the volume of blood and serum collected in the drainage , were not statistically significant and only suggested a slight advantage in the post - operative recovery process of patients treated with a. montana .
the variability is similar in the two groups and it appears not due to different responses to the drug tested .
the high korsakovian dilution used in this study compared to other studies could explain the failure to reach the threshold of significance despite the fact that the differences are quantitatively small but noticeable .
this high korsakovian dilution was chosen to surely avoid any toxicity from a. montana extract , to administer a harmless experimental treatment .
overall , the efficacy of homeopathic treatments in surgical settings is still controversial . in obstetrics , evaluating the effect of a. montana and bellis perennis on blood loss , oberbaum et al
. found that the mean hemoglobin levels remained the same after the administration of the homeopathic treatment whereas the levels decreased significantly in the placebo group ( 12.7 versus 11.6 ; p < 0.05 ) .
a systematic review has analyzed a. montana in eight randomized controlled trials ( rcts ) from 1966 to 1997 .
two of the included trials , one on the effect of a. montana on the delayed onset of muscle soreness ( doms ) and the other on the prevention of post - operative complications , showed a statistically significant result in favor of the homeopathic treatment .
the other six trials did not demonstrate statistically significant differences , but some of these trials were not considered qualitatively adequate for a proper meta - analysis .
. only one of the three rcts on doms and none of the two on surgical patients showed statistically significant between - group differences , in particular , on the recovery after total abdominal hysterectomy and on the stripping of varicose veins [ 13,28 - 32 ] . in a double - blind , placebo - controlled clinical study involving patients undergoing prolonged venous perfusion ,
a. montana treatment also slightly increased a number of coagulation factors and platelet aggregation . in vitro studies
in fact , different authors have shown that helenalin , the most active component of a. montana , not only blocks the transcriptional nf-b in t - cells , b - cells , and epithelial cells , but it also inhibits human neutrophil migration and chemotaxis and the activities of 5-lipoxygenase and leukotriene c4 synthase .
all these mechanisms are known to be associated with the induction of pain and inflammation , as observed in animal models of inflammatory pain . however
, these studies were conducted with pure helenalin rather than with plant extract and with much higher doses than those used here . a recent work carried out on human macrophage cells differentiated with interleukin-4 demonstrated that homeopathic doses of a. montana stimulate the expression of genes involved in the repair of connective tissue and , in particular , fibronectin . given the importance of this protein to the adhesion , proliferation , and movement of cells ( both epithelial and connective )
, this could be a further target at the cellular level of this plant s action .
undoubtedly , one as yet unsolved problem of homeopathy concerns the mechanism of action of dilutions so high that the presumed active substances are often not detectable in molecular terms .
many laboratory studies that use homeopathic dilutions report dose - response curves that are non - linear and sometimes pseudo - sinusoidal , with peaks occurring at different dilutions , alternating with other inactive doses [ 37 - 39 ] .
in relatively recent times , evidence has been found , especially in physicochemical studies , pointing to the presence of nanoparticles even in extremely high dilutions , or the formation of coherence domains among the molecules of the water  alcohol solvent , as predicted by quantum electrodynamics .
although these findings fall outside the scope of the present work , if consolidated by further experimental studies , they might furnish a basis of plausibility to this complementary pharmacological approach .
the main limitations of the study were the relatively small sample , the analysis of post - operative recovery , which was limited only to 5 days , and the use of a high korsakovian dilution which could have negatively impacted on the statistical significance of our findings .
observational studies with different korsakovian dilutions could be useful to highlight any significant effect of a. montana and further validate these findings .
the scientific community often claims that homeopathy effects are not supported by rigorous clinical trials .
this study , although reporting statistical significance only for some specific data settings , suggests a reduction in post - operative blood loss and seroma production in a group of women who underwent breast cancer surgery and treated with a. montana 1000 k.
 aim : this study aimed to evaluate the benefits of arnica montana on post - operative blood loss and seroma production in women undergoing unilateral total mastectomy by administering arnica montana 1000 korsakovian dilution ( 1000 k).materials and methods : from 2012 to 2014 , 53 women were randomly assigned to a. montana or placebo and were followed up for 5 days . 
 the main end point was the reduction in blood and serum volumes collected in drainages . 
 secondary end points were duration of drainage , a self - evaluation of pain , and the presence of bruising or hematomas.results:the per - protocol analysis revealed a lower mean volume of blood and serum collected in drainages with a. montana ( 94.40 ml ; 95% confidence interval [ ci ] : 22.48 - 211.28 ; p = 0.11 ) . a regression model including treatment , volume collected in the drainage on the day of surgery , and patient weight showed a statistically significant difference in favor of a. montana ( 106.28 ml ; 95% ci : 9.45 - 203.11 ; p = 0.03 ) . 
 volumes collected on the day of surgery and the following days were significantly lower with a. montana at days 2 ( p = 0.033 ) and 3 ( p = 0.0223 ) . 
 secondary end points have not revealed significant differences.conclusions:a . 
 montana 1000 k could reduce post - operative blood and seroma collection in women undergoing unilateral total mastectomy . 
 larger studies are needed with different dilutions of a. montana to further validate these data . 
INTRODUCTION
MATERIALS AND METHODS
Study Design
Endpoints
Sample Size
Study Treatment
Concomitant Therapies
Statistical Analysis
RESULTS
DISCUSSION
CONCLUSIONS