MEDIAN NERVE : NEUROPHYSIOLOGICAL PARAMETERS IN THIRD TRIMESTER OF PREGNANCY Introduction

An examination of neurophysiologic features of median nerve in third trimester of regularly controlled normal risk pregnancies is performed at the Department of Neurophysiology of Primary Health Centre in Tuzla during January / April . Examined group consisted of  young females in third trimester of pregnancy, and average age of , ± , years. Control group consisted of young healthy females with average age of , ± , years. Symptoms and signs of carpal tunnel sy. (CST) had  patients, but diagnosis is neurophysiologically confi rmed in  () patients. In group of pregnant females without symptoms  (,) patients showed neurophysiologic evidence of CTS. Sensory velocity of right median nerve was signifi cantly lower in pregnant group of patiens (p=,), but area of sensory potentials on both sides were lower in pregnant group (p<,). Area of CMAP of right median nerve was signifi cantly lower in pregnant group (p=,). Signifi cant diff erences in CTS group compared with control group were in sensory velocities of median nerve (left median nerve p=,, right p<,), and area of SNAP of both sides (left p<,, right p=,), but area of CMAP right (p=,). In CTS group  females had unilateral and  had bilateral neurophysiological changes. Our conclusion is that neurophysiological parameters of median nerve in third trimester of pregnancy are changed mainly due to high prevalence of CTS that might disturb quality of life and have psychological and physical implications on future mother. Hence, it is necessary to, continuously, pay enough attention in prevention or treatment of mentioned syndrome in this population group.


Introduction
Although, pregnancy is physiological condition, for some neurological diseases pregnancy presents additional factor of risk, e.g.carpal tunnel syndrome (CTS) which is the most frequent neurophaty occurred because of clamp.Many studies indicating that approximately  of pregnant women simptoms of CTS ().Actual incidence of CTS during pregnancy is ranging from  - ().Th is syndrome is most frequently diagnosed in second and third trimester ().Th ree quarter of women have bilateral symptoms.Half of multiples had similar symptoms during prior pregnancies.Preggies are more often predispositioned for development of CTS in second half of pregnancy, because retention of fl uid is often in later stage of pregnancy which causes swelling of tissues.Woman who has to take off their rings because of edema have this syndrome two times more expressed with symptoms (), and also woman with CTS symptoms more often have preeclampsia, hypertension and edema ().Italian study on frequency of carpal tunnel has found clinical signs in  of woman while neurophysiological indicators confi rmed diagnosis in  of preggies.Visible correlation between edema and neurophysiological fi ndings is notable ().Increase of weight and retention of fl uid as a result of decrease of venous circulation and changes in hormonal status, including increased serum of estrogen, aldosteron and cortisol, are increasing the frequency for occurrence of this syndrom.It is suggested that, also, increased level of prolactine could be ethiological factor in development of CTS becaue symptoms are getting worse during the night, which is coincidence with diumal level of prolactine ().Relaxin could also be potential ethiological factor due to his presence in high concentration from  th week of pregnancy and his reduction  hrs after delivery.Presupposition is that this could lead to relaxation of lig.Carpi transversum, which leads to his flatness and compression of n. medianus ().Objective sensory changes often include tactile discriminations, damage of sensibility for touch and pain with preserved eminence of thenar.As a consequence of compression neural structures, rigidity of fi ngers is very often.But in progressed stage, atrophy of muscles of thenar (particulary m. abductor pollicis brevis) is also present.By percussion of carpal tunnel area , in   of patients, it is possible to cause Tinel's sign which is nos specifi c sign for this syndrome.Flexion of patients hand lasting for one minute (Phalen's maneuver) or hyperextension of wrist (reversre Phalen's maneuver) could reproduce symptoms.Th is test has  of specifi city but very low sensitivity.Firm pressure over the carpal tunnel for approximately  seconds is reproducing the symptoms (so called.Carpal compression test) ().Sensitivity of this test is   and specifi city is .Palpatory diagnosis implies examination of soft tissue in carpal area with sensitivity of   and specifi city of  or higher ().Electrophysiological studies, including electromyography (EMG) and nervous conductive studies (electroneurography ENG) are used in combination with specifi c signs and symptoms and they creating criteria standards for CTS diagnosis and exemption of other neurological diagnosis.Th e most sensitive electrodiagnostic test for CTS is a study of sensory conduction of n. medianus, and it shows extended distal latence and slowing down the speed of sensory conduction through the wrist in  to   of patients.Recording the latence on a short distance in fl ow of n. medianus from palmar part to the fi st and comparing this latence with ulnary nerve on the same distance (conductive studies on palmary nerves) may increase sensitivity of conductive studies of sensory nerves ().Th e most sensitive test for an early diagnosis of CTS is determination of sensory speed of conductivity by stimulation of the fi rst fi nger and registration on the wrist ().Sensory potential could be absent, and most of the patients with medium to serious nerve damage have prolonged distal motor latence of n. medianus, reduced and expanded M-potential.If motor fi bres are caught, result of that is weakness of the fi ngers and muscular atrophy: lumbrical (I and II), short abductor, oponens and short fl exor of the thumb.Electrophysiological studies are giving the exact evaluation about how serious nerve damage is.Patient with medium CTS have only a sensory abnormalities.Th ose with sensory and motor abnormalities have moderate CTS.Evidences of axonal loss (e.g.attenuated or absent sensory or motor response on distal from carpal tunnel or neuropathological abnormality on pin EMG) are classifi ed as a serious CTS.Th is kind of neurophysiological changes are used for evaluation of eventual modal treatments ().

Examinees and Methods
Study is performed at the

Discussion
It is visible that major number of parameters of n. medianus in third trimester f pregnancy is changed: in velocity of sensory conduction of n. medianuss dex., ara of SNAP on both sides and area of CMAP on the right side.Change of those parameters, of course, is referred to patients with CTS.In examined pattern of preggies in third trimester,   of them had CTS.Prevalence of CTS in third trimester of pregnancy in one study was similar to this what we have found in our study and this prevalence was  ().But, clinical fi nding by itself, without electroneurographical confi rmation, was not enough to give final diagnosis of this sy.This sy. was proved even at examinees who had no symptoms, although in minor number (,).Th is means that, for defi nitive diagnose of this disease, clinical examination is very important but it is necessary to perform defi nitive electroneurographical confi rmation as well.In one study performed in Iran,   of preggies had CTS, , of them had bilateral form and , of them had a serious form of CTS.Prevalence of clinical symptoms was  and prevalence of signes (Phalen's and Tinnel's) was  ().In our study,  woman who were pregnant for the fi rst time had CTS.In Seror's analyses (), in third trimester of pregnancy, symptoms occurred at  patients, conductive block, motor or sensory was found at / patients and serious denervation occurred at  patients.Based on our annotation, if CTS in pregnancy is proved, it is possibly that he will be bilateral () than unilateral.Additional anamnestic data showed that from  preggies with unilateral CTS even  of them had professional risk of getting this disease.According to data from the literature, ¾ of woman are with bilateral symptoms.Half of those who were pregnant before had similar symptoms in previous pregnancies (,).According to a study,  woman of middle age . +/-. with for the fi rst time identifi ed new symptoms of CTS in pregnancy,  of them were acctually at fi rst pregnancy.Th e most frequent appearance of symptoms was in in third trimester () and most of them were bilateral ( numbness,  pain) ().Conductive velocity of n.medianus (both sensory velocity and motor latence) in examined group was signifi cantly changed in the right hand, not in the left, which is explained based on physiological diff erences related to dominant and nondominant hand.Dominant hand, the one that was used more often then the other, also has major predisposition for appearance of CTS.It is interesting that non of those patients visited neurologist before and we also have to notice that this study was performed on random pattern of examinees who were coming for regular control examination at gynecologist.According to one study of woman with CTS symptoms in  of cases were with disorder of hand and rhythm of sleep and only  of those patients mentioned those symptoms to her doctor.Only  ( of those who were complaining about symptoms) were treated and only one half of those cases got better ().It is ironic that in period when woman needs a healthy hands so she could prepare herself for a labor and care for the baby, woman with CTS often have painful and numb fi ngers, primarily thumb.Also, additiona problem is the fact that because of the pain pregnant woman cannot sleep and rest properly which causes further exhaustion and violation of quality of life.Our study shows that this problem is not getting enough attention.Th e fact that non of pregnant patients did not seek for help because of painful and numb hands, and the fact that  preggies with unilateral CTS in their anamnesis had painful hands even before pregnancy is telling us that patient as well as medical provider is not informed very well.Adequate, in most cases even very simple treatment or advice (position of the fi ngers while sleeping, diet, orthrosis) could minimise possibility of clinical occurrence of CTS in population of preggies so that they could easily endure severity of pregnancy and labor as well as breastfeeding period.Based on this we can make conclusion that medical providers are mostly focused on adequate growth and development of the baby, while pregnant woman is placed into a second plan.Her health is actually dictating adequate care of the baby.Th ese problems should be pointed out continuously, prevention modes should be offered and medical providers should be educated (specially those who are working on consultation of pregnant woman) as well as patients how to recognize the symptoms, if it is possible, and how to treat them which is very important for the mother as well as for her descendants.
Control group consisted of young healthy females with average age of , ± , (-) years.(,) of them had a history of previous labors.Examined group consisted of  young females of average age of , ± , ( -) years and  () of them never had a labor.Average age of pregnancy was , ± , ( -) weeks.Th is is *random pattern* od preggies that were regularly coming for gynecological examinations at Department for medical care and service of healthy and pregnant woman in Medical Centre in Tuzla, and all of them accepted this neurophysiological analyses.First that was taken was medical history, then examination was done and after that neurophysiological processing.Condition for this examination was that neither of examinees had polineuropathy or any other sickness which could infl uence on speed of nerve conduction.Testing was performed at room temperature and physiological temperature of the skin of examined females in lying position.At the beginning, they were divided on those with and without clinical symptoms (based on torpid fi ngers at day or night) and signs (Phalen's and reverse Phalen's tryout, Tinnel's sign and tenar atrophy).n.medianus at the wrist by comparison with control group were in velocity of sensoric conduction of n. medianus dex., area of SNAP on both sides and CMAP area on right side (Table.).
Department of Neurophysiology of Primary Health Centre in Tuzla during January / April .COMPRESSION OF N. MEDIANUS AT THE WRIST Average age of preggies with verifi ed CTS was , ± , ( -) years and  of them were with fi rst pregnancy.Average age of pregnancy, in weeks, was , ± , ( -).Neurophysiological parameters of patients with CTS are showed in Table .Signifi cant diff erences in parameters of preggies in third trimester by comparison with control group were in velocity of sensoric conduction of n. medianus dex., area of SNAP on both sides and CMAP area on right side (Table .).Signifi cant diff erences in parameters of preggies in third trimester with compression of