 So, I will be discussing the techniques and complication avoidance in endoscopic pituitary surgery. Endoscopic pituitary surgery is when the endoscope is used as the sole or the only visualizing tool in place of microscope, it utilizes the endonazole route via natural air passages to reach to the rostrum of the spinoid. It has distinct advantages and it has been proved to be better than microscopic surgery because the volume of exposure is far superior as compared to microscope and it provides better visualization of anatomy, pathology and a phenomic close up view with multi-angle view permitting to look around the corners. Now if you see this scenery on the left and if your target is this green scenery there, this is on the most left side is by gross or by using the headlight. Now next is when you see with the microscope that it is enlarged and you see more and more detail and the last one is when you put your neck into this window and you look around so you can see everything all around. So this is the difference between microscope and endoscopy. Now illumination and magnification of endoscope is unique it gives a flash light effect. This means that you can study the details, finer details of a structure if you take the endoscope close to the target you can see the finer details. So it permits a better distinction between the tumor and normal pituitary and similarly a better distinction between the arachnoid and diaphragm so that you can identify the minor CSF leaks as well. It reduces the morbidity and post-operative course is very comfortable because there is a minimal mucosal dissection you are not using the hardy nasal speculum and you are not packing the nose after surgery. So it is very well tolerated and appreciated by patients however it has many disadvantages and the most important is that it gives you a 2D image. So there is difficulty in depth perception but this can be compensated by constant in and out movement of an endoscope during surgery. So you fix up some surgical targets and you get a 3D perception and a bimanual dissection may not be possible if you yourself are holding the endoscope. So you need another surgeon and a binaustral technique so that your both hands are free and you can do a bimanual dissection. And as already told to you that it produces a barrel type spatial distortion of the image it is not a real image it is a distorted image and in periphery the periphery are blurred it is a X as a obstacle in the narrow corridor already a narrow corridor and where you put the endoscope so it occupies the space and it acts as a clock gear mechanism where if one component of this fails then you cannot proceed further surgery. So because of limited space there is limited maneuverability of the instruments and limited zoom capacity of the endoscope so that the instruments if you take them deep and if you put more zoom they may collide together. So use of multiple simultaneous instruments in nasal cavity have a greater risk of requiring exhesion or lateralization of middle terminate thereby sometimes to create a space you may have to partially or completely excise the middle terminate and most important and last is that it is a different hand eye coordination it is all together a different so this is why there is a steep learning curve. Now existence of this steep learning curve is there and this is the time when complications can occur so complications may be non endocrine and endocrine of the non endocrine if we go according to the stages of the surgery in nasal complications it is the bleeding or epistexis which may be early or delayed and it is always the cause is mucosal branch of sphenopyleton artery even delayed epistexis is also because bleeding from this artery now anosmia or hyposmia when you coagulate the mucosa in the upper part of the nasal cavity sphenoid maxillary sinusitis mucosial or synechia and patient presents with symptoms of headache dizziness and fever 2 to 3 months after surgery others could be carotid injury which should be immediately recognized and treated by putting a stent and this occurs when the surgeon gets lost and he is not properly oriented so the navigation and Doppler may help you in identifying these arteries. CSF ryanoria which can give rise to meningitis or nemocephalus postoperative hematoma in the residual tumor or pituitary apoplexy postop apoplexy the tumor residue may be there then there may be subarachnoid hemorrhage blood medical into the arachnoid and it may cause cerebral vasospasm and there may be mortality and these are the three things like meningitis, subarachnoid hemorrhage, residual tumor hematoma and these carotid injury they can kill a patient if you are not very careful with this. Endocrine complications may be a development of new pituitary hormone deficiency which patient does not have means the normal pituitary had been taken causing diabetes and pain hyper pituitary. So, this micro surgery has been linked to as if you are eating with a fork and knife whereas the endoscopy is like you have one chopstick in each hand so it is entirely altogether a different skill and hand-eye coordination so this is why the learning curve exists and this is the most important to learn at this stage. Now a sudden change from microscopic to endoscopic may be difficult and discouraging so change slowly and progressively so initially if you are at present doing sublaviol pituitary by microscope first change to endo nasal then endoscope assisted with the retractor on then with endoscopic without retractor and first do the cellular stage because you are more conversant with the cellular stage and then do the nasal stage and finally all endoscopic procedure full endoscopic procedure so this step-wise progressive learning brings confidence and ability to tackle any complication and it has been proved that with increasing experience there is improvement in duration of surgery, pre-op visual deficits, endocrine remission, post-op hyper pituitary mucozole trauma, post-op discomfort, hospital stay and CSF leak and really your post-operative results start showing a significant improvement once you have done 100 cases. Now there may be frustrating experience in first 20-30 cases because of difficulty in the initial phase of procedure but these can be minimized and overcome by knowing your endoscope, by learning endoscopic skills, by detailed understanding of the endoscopic perception of the anatomy following the techniques step by step so every step you identify the structure and follow the procedure you are less likely to cause complication and knowing the tips and tricks and this learning obviously needs commitment and dedication. Now about the endoscope itself that all the cables of light, camera and irrigation they should be tied together to the shaft of the scope and they rest on the table on left side of the patient so they are out of your surgical field. Now endoscope is held like a flute in the left hand so you hold it like a flute. Now index finger and thumb they can be used to focus the camera or for orientation purposes. Now use a 0 degree 4 millimeter 18 centimeter endoscope usually in adults and 18 centimeter is used up to nasal and spinal stage after that 30 centimeter may be used in children we use 2.7 millimeter endoscope because of the space. Now 30 and 45 degree are used at the end for the inspection of the remanents and completion of the tumour section and endoscope with external sheath is useful whichever it permits irrigation and cleaning of lens it avoids frequent in and out movements of scope so it reduces your surgical time. Instruments used are straight and long which are curved at the tip otherwise you will not be able to see the tip they should be slightly curved at the tip. The precision grip instruments are always preferred because the power grip instruments you cannot have a control in the depth whereas precision grip where your palm rests and then you can use these precision grip instruments and the suction coagulator I find is very important because it it makes your operation clean easy and fast. After a spinotomy the endoscope may be mounted on the holder or another surgeon holds it which acts as a co-pilot and to the main surgeon who is a dissecting surgeon and it provides a 3D perspective. Now the job of the assistant surgeon of co-pilot is that he holds the scope other way like on the reverse like a pilot so he is on this side and he holds it like this. Now he should support his elbows so that for a longer period he can hold the scope for you. He stands on the left side of surgeon at head end of the table now he moves the scope in relation to the instruments so a pilot and co-pilot they do a couple dance so if he goes in he follows. Now scope should always pass above the inferior terminate for pituitary surgery. Now always keep checking the proper orientation and proper orientation means all the buttons and the scope should be facing screen then only you are properly oriented. If your buttons are on this side this side you are disoriented and especially these should be checked after each insertion and exit of the scope. Now just to do some in and out movements inside the nasal cavity to judge the depth and fix some surgical landmarks which will give you 3D perception. Now introduce scope slowly like you are going through a tube and without touching the wall otherwise your tip will get soiled and you may have to take it out again. Now avoid quick movements in proximity to that target while introducing escape take the advantage of elasticity of the aila lift or deform the aila like this and keep it at 11 o'clock so endoscope should be kept at a 11 o'clock position. Avoid injuries to nasal mucosa by insertion of instruments by endoscope guided visualization keeping the suction at low setting and if there is bleeding from the mucosa it is better controlled just by infiltration rather than coagulation. Now instruments introduced taking the advantage of rigidity of the floor just first the instrument first thing is along the floor so you will not injure the middle terminate or other terminates and instruments and scope they should not touch each other and they should never cross over. Try to make the path as straight as possible so if you see a semilunar signs means your scope is touching that issue so just rotate it if the lens is fogged just irrigated with bombs aligned it will be okay and when you enter the nasal cavity you first get an aerial view of the whole area so that you know what is where. Now distance between the tip and scope should be 1 centimeter and never pull a tissue or hold a tissue if you do not see the tips of the instrument. Now the posterior septal artery which is branch of sphenopalatine which in turn is branch of internal migratory lies at superior lateral to koana or inferior lateral corner of sphenoeth medial recess or medial posterior corner of inferior margin of middle terminate. This artery can be coagulated when the excess is made between the middle terminate and nasal septum for anterior sphenotomy to prevent bleeding during and after surgery. Now how to drill? You use a drill and drill is first taken through the nostril close to the target when the tip can be seen. Now make it on touch the target of the drill and give a drill it in the busts like a paintbrush. Now remove the drill only when it has completely stopped dry drilling with burr helps in hemostasis and it stops bony bleeding while drilling keep endoscope away and zoom so that you avoid the swelling of the endoscopic lines. Now sometimes in between in the stage of a surgery you may notice that more and more blood is coming so this is nothing but a blocked koana effect so what you do is that in between you should keep sucking the koana the blood collects there and then when you manipulate the blood comes up and remove the coffin effect now coffin effect is that you are struggling that there is no space so for that you do a wide sphenotomy so you will be very comfortable. Now angled scope visualizes opposite to the light cable so if you want to see up then your light cable should be down and then instruments now should pass above the scope. Now to begin with in the beginning you must select the cases and for a beginner a best case is a known functioning adenoma with a well nematized sphenoid sinus and tumor confined to cellar and the worst case is conical or pre-cellar type of sphenoid pneumatization with a functioning adenoma of agromegaly and cushing because this mucosa in these patients is fragile hypertrophied and it bleeds and the don't do recurrent or dumbbell or giant pituitary adenomas to begin with by endoscopy. Now always review the preoperative MRI and CT scan for assessment of nasal airway for presence of DNS or a conchhabulosa anatomy of pharyngeal sinuses for extent of nematization and intra or inter sphenoidal septum, cell enlargement, erosion, anatomical variation or kissing carotids very important and sometimes you may see a mucosal thickening which may suggest a sinusitis or a pituitary apoplexy. Now we use a topical nasal decongestants in the form of xylomethazoline one hour before shifting patient to operation room and then adenally one in one thousand three ampules in 30 ml of xylokane is used. The position is supine with trunk elevated 20 degree knee and hip flex which provides a easy access to the middle turbinate. Now head is rested either on the hot shoe or in a three pin when you want to use the navigation. Now most important is that the chin for headline is parallel to the floor this must be parallel to the floor and there is a 15 degree turn towards the surgeon and a contralateral tilt. Now on the operation table we do a super selective packing and in this the two to four cotton patties which are soaked in decongestant and squeezed and then these are put inserted between the middle turbinate and nasal septum take them to koana and then from anterior to inferior to push them posterior superiorly into the isphinoethmoidal recess. Let be there for five minutes to create space and to widen the isphinoethmoidal recess. Once space is created now fresh pattern kotties are pushed back in isphinoethmoidal recess and the rostrum isphinoid sinus and again left there for two to five minutes and I can assure you that if you spend 10 15 minutes in this your next stage of operation will be very smooth. Now when you are packing the nasal cavity the bionate should be opened in craniocaudal direction because you will not be able to open it like this and you will injure them because pack the one nostril at a time and if you see any synechia don't cut them by seizures cut them by diathermy so it doesn't bleed oropharynx is packed and propofol anesthesia infusion reduces the bleeding and ideal blood pressure of the patient for this pituitary surgery should be around 90 with pulse of around 60. Now the endoscope is inserted parallel to middle terminate at a angle of 25 degrees inferiorly to the koana first along the floor so you visualize the koana first and to see this you will see that inferior terminate points towards the east taken tube or tube elevation. Now koana is the anatomic ruffus point and now here you go between the septum and inferior terminate septum and middle terminate and reach to the sphenoethymodal recess. Now instruments are passed along the septum below the iscope through the lower part of the nasal nostril. Now there are many variations in endoscopic pituitary surgery it may be uninostril or binostril approach it may be two or four hundred techniques so we prefer four hundred techniques extent of resection of middle terminate to create a space which may not be resected at all partial resection or total resection but if there is a rule if you have to resect any of the terminate resect it partially only or leave some part of it because they act as a very important landmark surgical landmarks and type of repair of cella depending upon the CSF leak grade of the CSF leak. So before starting endoscopic pituitary surgery one must know all these modifications so that you can tailor it according to the requirement in a given case for example a uninostril approach is very good for in a patient with DNS who has a micro adenoma so why to go on both sides and through the capacious nose nostril you can remove it by one nostril only. So a uninostril or paraceptal approach side which is more is used which is less obstructed by nasal septum radiation and which is controlled lateral to enlarge middle terminate. Now lateralized legions, micro adenomas are best approached by contra natural nostril because you have a tendency to go to other side. Now surgical technique stages are nasal, sphenoid, cellar and reconstruction stage and recognition of important landmarks during each of these stages is the key for safe exposure. First thing is that you lateralize the middle terminate by pushing it with the deceptor over the patty without fracturing it or if you still the space is not being created then what you can do is you out fracture it immediately first and then push laterally so that space is created and this is how it is done. Now neuro navigation is important for beginners when they are just starting for few 10-15 cases I always used it for re operations because your anatomy is distorted you do not know where bone is there what bone has been removed for extended trancessional order for distorted anatomy of the sphenoid sinus when it is not straight anatomy kissing carotids or dumbbell or giant pituitary Now sphenoid ostium marks the superior limit of opening into the sphenoid sinus and if there is a one constant once you have done about 20-25 cases you will learn this that the inferior margin of middle terminate leads to the clival indentation at 1 centimeter below the level of cellar floor and it is a very constant surgical landmark so this is why you can avoid and after doing 20 cases you can avoid using the C-arm. Now ostium is identified medial to root of superior terminate in the lateral rostral corner of sphenoid rostrum. In 30% cases the ostium may not be visible so a observation of air bubble with secretions and probing loss of resistance it will just locate it very easily. Now if still you do not find it then what you can do is a thin anterior wall of sphenoid below or caudal to the expected site of ostium that is the 1.5 centimeter cranial to the roof of kuana so there it is a thin bone which is known as fontanel of sphenoid bone where you can just perforate it to make a artificial septum and this is the septum nasal ostium you see sphenoid ostium a typical sphenoid ostium there. Now mucosa over the rostrum of sphenoid sinus is coagulated nasal septum is now gently pushed medially fractured and pushed to other side. Now the submucosal dissection along the contralateral side of sphenoid rostrum is done to visualize the other side ostium and this gives a classical owl eye appearance so if you see this this is the submucosal dissection has been done and the hair the vomer is the nose and these two sphenoid ostia they act as the eyes. Now sphenoid ostia is enlarged medially and inferiorly to avoid an adverent entry into the anterior cranial if you enlarge it superiorly you may enter into the anterior cranial fursum. Now rostrum of the sphenoid is removed now if V shaped anterior sphenoid or tomi is done from inferior margin of middle turbinate vertically up to the sphenoid ostium for about 15 to 20 millimeter. Now posterior one-third of nasal septum is removed by backbiter and this is how this backbiter works that you come through the other nostril and you take this and then you just remove the nasal septum. Now cordially vomer is drilled up to the pterigo sphenoid synchronosis or canal for median nerve which is seen at 5 or 7 o'clock position creating space under the floor of the cellar where you are able to pass your suction at least otherwise your instruments will get entangled somewhere with the bones so this much drilling should be done and laterally you go up to the crest which marks the junction of sphenoid with the ethmoids and now this is the drilling of the vomer. Now there is an approach called cavity and half so here what you do is through the ostium you open the Parsons bar and then you open the Bulleith modulus so once you open the Bulleith modulus this is used to keep your scope there so this does not occupy your space in the sphenoid cavity so this is what is called cavity and half approach. Now smoothen the sphenotomy margins with the diamond drill paramedicine septum within the sphenoid sinus they often lead to carotid or optic nerve so they should be removed only when it is mandatory and they should not be removed by the forceps they should be drilled with diamond drill gently to avoid injury and now once you have removed all this so your scope is out now you have to get oriented and you can still identify the midline by the remains of the rostrum and vomer down so you know where is the midline and by staying between the two carotid bulges so that is the midline so you should not get disoriented at this stage. Now anatomical landmarks are identified in a panoramic view which mimics the fetal phase in the center is the cellar rostralis tuberculum celli at 12 o'clock position cordially is clivalry says at 6 o'clock position optic protuberance at 10 and 2 o'clock position carotid protuberances at 5 and 7 o'clock position and cavernous sinuses at 3 and 9 o'clock position so if you are convergent with this anatomy you are less likely to have problems and this is the thing you see here the spinoid septa is paramedial the internal septa of the spinoid is paramedial now a medium sized bar of 3 to 4 millimeter is used to drill the cellar and it's a gentle lazy drilling if you drill it it will enter into the dura so a gentle lazy drilling with diamond bar under low speed is done egg shell is produced and which is dissected and broken with fine spade dissected and the extent of cellar bone removal is that you should be able to see four below lines means superior intercavernous sinus inferior intercavernous sinus and both cavernous sinuses on both sides and now this is the cellar floor is being drilled this is the enlarged cellar in a patient now mucosa on the posterior side of spinoid sinus is not stripped it is just coagulated because stripping causes bleeding repeated warm cell and irrigation stops bleeding at this stage and clean the field a small hole is made in the inferior lateral part or center of the cellar and the anterior wall of the cellar and floor is removed circumferentially and dura is coagulated and open now you may open dura in a linear way but mind it and keep it in mind that superiorly the arachnod may bulge in front of tumor and you may produce a CSF leak so just avoid the superior part usually use a cruciate incision but the disadvantage of this is that it exposes whole of the tumor in one go and if it is a large tumor then part of it may be missed by doing surgery so this is a linear incision with a retractable copper banker knife endoscopic knife so the knife comes only then you are in and now one more important this copper banker knife is a very long straight handle so again you have no control so open the dura in the center of the cellar and then either you cut it by the scissors or you make it the incision in the periphery and then you go because you will not have a control so you may cut cavernous sinus if it is exposed by this knife and I usually prefer to open dura like this first make a central and then two cuts at five and eight o'clock position and raise a inferior flap so advantage of this is that you remove the basal posterior and lateral part of the tumor first and the half of the dura which is not open it acts as a retractor and it supports the superior and anterior part of the tumor so once you have removed the posterior and lateral part then only you extend these incisions and then you remove the superior and lateral part and this is how the dura is open first open in the center and then make cuts now the when you open the dura cut the dura only not the tumor capsule and then develop a plane between the tumor capsule and dura and make it in flaps this we have already covered the basal part is removed and now do not pull the tumor towards the scope otherwise it will soil your lens so what you do is when you hold the tumor move it sideways other side so that you see that something is not adherent there so always do a dissection on the sides now for removal of the tumor the tumor first should be mobilized free and then put into the section so mobilize it free and then you take your section so it sucks it off now the rostral part of the tumor is removed circumferentially from periphery towards the center and progressively descending supracella tumor is continuously removed concentrically now a tumor decompression is done by by manual dissection and a curate is held in the left hand or by double suction method where two sections are used and left sided suction is used to retrick the dura or dural flap and then you suck it by right sided suction now after gross total removal you take the endoscope to the target to study details and withdraw your instruments so now you do a first you a detailed study now you withdraw the endoscope and take your instruments further remove the tumor so it's a dynamic process that you see the details of it remove it then again take it like this and this is the tumor sent see now normal pituitary is yellowish in color firm in consistency and there is a vascularity present on this and normal pituitary it should always be predicted in a pre-operative MRI that whether it's a post posterior or anterior or down or whatever and a normal and thinned out pituitary appears as a apron plastered to the under surface of the diaphragm which should be identified and preserved now in functioning micro adenomas a thin shell of normal pituitary is shaped along with the tumor to increase or to enhance the chances of cure now angled endoscope is taken into the cellar to examine the tumor remnants which are removed with curved curates under direct vision to examine the medial cavernous wall when you rotate 30 degree endoscope ask the assistant to rotate the camera as well so that you are properly oriented all the time now space between the posterior and carotid siphon which is like a reverse s represents the ideal entry point for removal of tumor from posterior segment of the cavernous sinus now finally inspection of cellar is done in clockwise fashion starting with six o'clock position using a 30 degree endoscope so you see and go all around and visualize the whole cavity now push the diaphragm with cotton and remove the tumor using curved suction from the recesses under the diaphragm by using 40 degree endoscope now arachnid may bulge down to diaphragm in front of thinned pituitary again caution CSF Lee the last piece of tumor is often located at the site of insertion of pituitary stock the most common sites which are found to retain tumor is the angle between optic nerve and carotid artery at medial OCR and under the anterior lip of the dura at the level of superior intercavernous sinus now this is after complete oxygen the arachnoid is bulged now a failure of diaphragm descent indicates that there is some retained tumor in the supracellar system and pulsations visible in the diaphragm is a robust finding of a total tumor removal no foreign material should be left in the spinoid sinus intact residual mucosa keeps the spinoid sinus as an air filled cavity and it's more physiological if whole of the spinoid sinus is to be packed because there is a copious CSF leak in that case you must take out all the spinoid mucosa otherwise there will be mucosil formation later on to avoid crusting leave minimal row surface of the bone and now middle terminate is pushed back to normal position and this helps is rather it is essential to keep the maxillary because you have lateralized it so it is essential to keep the maxillary sinus open and this is after complete oxygen the fat is placed there and instead of small pieces a single or a large fat piece should be used you may use the bone pieces for reconstruction of cellar or you can use a rescue flap so now you use rescue flap so that CSF leak is not there lumber drain depend on individual choice if arachnoid tear occurs should be avoided at all costs but if occurs then prevent further opening of the arachnoid seal it immediately with glue and keep one petty over it over the defect so that blood doesn't go in and cause various viscose spasms later in the end while selva to see for CSF leak and in macro adenoma the tumor cavity is filled with fat because it prevents empty cellar syndrome formation and it prevents the rupture of the arachnoid which can occur later during extubation in postoperative period and no nozzles pecs are used so these are just two three small videos which show you all the possible techniques which have been used this is the kuana now going up you see the spinodostia there and now you coagulate the mucosa medial to the ostea and make a cut and now you dissect the rostrum now septum has been pushed to other side and is the submucosal dissection of other side and now you see the ostea of other side now you remove the rostrum and now you see the cellar you can see the midline cellar septum now the cellar opening is gradually enlarged now the dura is being opened and now you can see the pituitary tumor being taken for biopsy and then use the curates and first remove the inferior basal part posterior part and then the lateral part and you here you can use the double suction method also it if it is a cable it the suction dissects it very well and never pull it just give a traction so like this you just give a traction yeah and now you see the normal pituitary this white is and you always tend to look around that nothing is adherent to and gentle delivery and this is after the complete oxygen and normal pituitary preserved and this is the fat which is being packed and always see that once you pack the fat it should be pulsating means it would not be over enthusiastic of packing the cellar and then we put a glue there and push back the middle term it this is the other side middle term it which is replaced back now just small videos and this is the cavity and half you see now this this has been opened a bull-eath modulus and now here we started using the flap a small flap which is sufficient enough to cover the pituitary fossa and the dissection on other side now you see the rostrum submucosal dissection of other side both the austere seen and the boomer is seen and rostrum is seen now this rostrum is removed now we remove drill with the drill rather than with the force and now you see this is the cellar and this is the septum which has been doing now with the upcut the cellar is opening is being enlarged and now this is thin cellar so you can just with the deceptor only you can push it now this is the hole dura is exposed and now earlier I used to open it just linear incisions on both sides and remove the part of the tumor that so and once you remove the lateral and posterior part then only cut this central dura to remove the other portion this is for biopsy then we use the curate and then remove the lateral parts and now once this lateral and posterior part is removed now we cut this dura again and reflect it superiorly and now you see the hole of the tumor which is a anterior part and superior part which can be removed and now still see it may bulge like this but again you have to be very careful in dissecting otherwise you may produce arachnoid tear and if you can prevent carotid injury and arachnoid tear your whole of the surgery is very good you will not have any lethal complications and now you see here that capsule of the tumor which is being dissected from the arachnoid you can see the intact arachnoid and this is the difference between normal pituitary and tumor the tumor capsule will peel off whereas the normal pituitary will not so now after complete excision whatever remains is the pituitary and now I see some tumor in the posterior basal part so removed it further and now see you can see the further tumor and now this is the complete excision with normal pituitary picture out there and then same thing fat is packed there but again not to pack it too tight and this is a bath tub technique if you large piece of fat you put in there and just withdraw it little bit so that all margins from all sides will seal it and then you put to the glow keep the patient in hospital 4 inch verdict for 5 days and ENT referral only if there are some persistent complaints and if there is unsuspected post-op leak in the post-op period of the best way to treat it is to repack the it is concluded that the majority of post-operative complications can be avoided by gradual transition from macroscopic to endoscopic surgery by proper selection of cases acquiring hand eye coordination and endoscopic surgical skills by gentle handling of the mucosa by spending time in spinoethymidal recess widening recognition of important landmarks during each stage of surgery bimanual dissection and sequential tumor excision under vision by using extended approach in large supracellar or joint adenomas by avoidance of irregular tear and by preserving the normal pituitary. Thank you very much for your presentation.