The Study Of Single-nostril Transsphenoidal Approach For Pituitary Adenoma Microsurgery

Objective:Pituitary adenoma is a common intracranial neoplasm,the main measure to treat pituitary adenomas is surgery.There are two optional approaches for adenomaotomy.One is the transcranial approach,the other is the transsphenodal approach.The single-nostril transsphenoidal approach for pituitary adenoma microsurgery has become the first choice with the development of microsurgery.It meets the need of minimally invasive surgery more,characteristics of less trauma and higher safety and better effect.However,this approach has its disadvantages such as performing within narrow scope and under indirect observation.What's more,the structures surrounding the sellar region such as iternal carotid artery(ICA),optic nerve etc are so complicated and important,which would cause some fatal complications if accidentally injured.Therefore my experiment plans on measuring anatomical data, Searching anatomical mark,in order to provide some anatomical parameters for endonasal transsphenoidal microsurgery.As the same time to discuss the surgical techniques and curative effect of the microsurgical resection of pituitary adenamas in single-nostril transsphenoidal approach。Methods:Heads from 20 adults cadavers were studied which were embalmed using a 10%formalin solution.The brain was removed from each head,hypophyseal region was dissected with the aid of operating microscope.Special attention was directed to the diaphragma sellae and its opening,to split specimen by following center anterposterior axes,oberserve and measure the shape of nasal cavity department of anterior sphenoidal wall,the sphenoid sinus and its septae,the location and shape of sphenoid ostium(SO),the relationship between sphenoid ostium and the middle turbinate,the relationship between sphenoid ostium and vomer dissocation side (posterula together with pharyngeal portion).The location and shape of the sellar floor,the relationship between the sellar floor and superior extremity and posterior margin of nasal septum,posterior margin of vomer and sphenoidal crest.The relationship between sphenoid sinus and ICA,ON.The location and shape of intercavemous sinus(IS),and so on.The distance from sphenoid ostium to the inferior margin of vomer dissocation side,the sellar floor(SF),the tuberculum sellae,the center of the dorsum sellae,ICA and ON were measured precisely.In the same way the distance from anterior nasal spineto sphenoid ostium,the sellar floor,ICA and optic nerve were measured too.Pictures were taken on the specimens impersonally and timely in the process of experiment.We collect 62 patients which are operated by single-nostril transsphenoidal approach,before operation:they are all examed by CT and MRI,endocrine examinations.And the same items are examed again after operations to evaluate the effect.Results:(1) The diaphragmal opening was round in 70%of the cases,elliptical in 30%,and 5ram or greater broad in 90%.The mean thickness of the diaphragma sellae was 0.18±0.08 mm,20%of which was no more than 0.1mm.(2) The opening site can be located by the peculiar oval protuberance of the anterior wall of sphenoid sinus.(3) The sphenoidal ostium was elliptical in 90%of the cases,round in 10%.The anteroposterior distance of the sphenoidal ostium and the distance from its left to its right are 5.83±1.59mm(3.50～10.02mm),2.95±0.64mm(1.50～4.34 mm).(4) A sphenoid sinus with Complete pneumatization is named as all-sellae type,its percentage in all specimens is 85%,17.6%of which extend to occipital do the except for 3 case,85%sphenoid sinus have middle septum of which only 18.8%locate in the median sagital section.(5) The meant hickness of the sellar floor is 0.81±0.34 mm,70%of which are not more than lmm.Of the sellar floors,that the shape is flatness reaches15%.The relationship between the central section of sellar floor and superior extremity and posterior margin of nasal septum,posterior margin of vomer, sphenoidal crest is vertical.(6) The relationship between ICA and sphenoid sinus have two aspects,one is to be mutually apart(55%),the other is to communicate(45%), which formers carinae on the lateral wall of the sphenoid sinus,especially in the superior surface of posterior part.(7) The relationship between ON and sphenoid sinus: one is to be mutually apart(30%),the other is to communicate(70%),which formers carinae on the lateral wall of the sphenoid sinus,especially in the superior surface of anterior part.(8) Three main types of the intercavernous sinus are the anterior intercavernous sinus,present in 80%,the inferior intercavenous sinus(25%),and the posterior intercavenous sinus(15%).(9) The distances from anterior nasal spine to the sellar floor,the ostium of sphenoid,ICA and the optic nerve are respectively 70.20±0.98mm,57.29±0.68mm,69.66±0.74mm,70.95±1.03mm.The average distances from ostium of sphenoid Sinus to the sellar floor,optic nerve,ICA,the tuberculum sellar,the center of the dorsum sellar and to the inferior margin of vomer dissocation side(posterula together with pharyngeal portion) are respectively 14.62±0.80mm,13.25±0.99mm,14.38±0.82mm,15.03±1.21mm,25.24±1.08mm, 17.21±0.59mm.(10) In this group,total removal was achieved in 52,subtotal removal in 5 and partial removal in 5.No case has with hyponatremia.No patient died and all the patients were differently improved in sight and visual field after the operation.Conclusions:(1)The sphenoidal ostium is an important landmark of the anterior inferior wall of sphenoid sinus,when it is difficult to locate the sphenoidal ostium,the opening site can be located by the peculiar oval protuberance of the anterior wall of sphenoid sinus,the relationship between the anterior wall of sphenoid sinus and the middle turbinate.(2) The superior extremity and posterior margin of nasal septum and posterior margin of vomer and sphenoidal crest all can be used as landmark of sellar floor midline.(3)The upper limit of the opening of anterior wall of sphenoid sinus should not beyond the sphenoidal ostium to avoid subsequent opening of tuberculum sellae and planum sphenoidale.Pay attention to avoid develop ICA as the opening of the sellar floor is extended laterally.(4)The location of sinus intercavernous anterior and sinus intercavernosus inferior is on the way of endonasal transsphenoidal approach,it is possible bleeding seriously when the sellar floor is opened.(5)The diaphragrnal opening of Chinese are often larger than those of foreigners,so it is ease to develop CSF leakage during endonasal transsphenoidal approach.(6) This approach is especially suitable for pituitary adenomas because of protection of brain function,minimal invasion,few complications,quick postoperative recovery and short in hospital time.