A Novel Technique for Transpalatal Hypophysectomy

Abstract

Objective  A novel technique is described for transpalatal hypophysectomy as an option for sellar region surgery using a microscope and/or endoscope.

Technique  A straight submucosal tunnel (approximately 20 mm in diameter; 40–50 mm long—half the length required by conventional transsphenoidal hypophysectomy) is dissected in favorable alignment with the main tumor axis, providing a direct view that allows the surgeon to operate on large suprasellar tumors, even in cases of extra-axial expansion.

Results  In a 25-year period, over 50 patients benefited from this surgery. Macroadenomas devoid of extra-axial expansions were totally excised (76.5%), otherwise, partially (23.5%). Forty-nine patients (98%) were extubated soon after surgery. Mean surgery duration was 3 hour 32 minute, with 2 days 6 hour before free feeding was restored. Postoperative hospitalization under neurosurgical care averaged 6 days 6 hour. Currently, patients undergoing the procedure do not require nasal tampons and can eat soft foods soon after recovery from anesthesia. Although two patients (3.9%) presented with oronasal fistulae postoperatively, no episodes of severe hemorrhage occurred during surgery and there were no cases of liquoric fistulae, visual impairment, panhypopituitarism, or severe syndrome of inappropriate antidiuretic hormone secretion.

Conclusion  The new surgical approach is safe, effective, and well accepted by patients, who reported low levels of discomfort. Postsurgical complications or sequela are currently rare, but further operations should be performed using more appropriate materials, instruments, and equipment to allow comparisons with other techniques.

Introduction

In 1900, Franz Koenig (König) made the first attempt to reach the pituitary gland using a transpalatal-transsphenoidal approach. ^{1 2} According to Guleke ³ , the proposed access route was not well received by the medical community, and even the ensuing modified techniques, ^{4 5 6} including that developed by Preysing ⁷ in 1913, fell out of favor. Broeckaert ⁸ described Preysing's technique as entailing splitting of the soft palate and removal of the posterior part of the hard palate. In 1908, Ballance ^{9 10} tried unsuccessfully to operate on a patient using this approach. ¹¹ The technique was forgotten for more than half a century, until Trible and Morse, ¹² in an article from 1965, proposed the use of “transpalatal hypophysectomy” to “destroy the pituitary gland in advanced carcinoma of the breast and to treat the diabetic retinopathy”; this microsurgical approach involves resecting the posterior half of the hard palate, but injures the nasal mucosa, making the procedure laborious for the surgeon and postoperatively uncomfortable for the patient; the experience with the technique, however, remained limited, and the procedure proved insufficient to ensure proper healing if the patient had to be reoperated. In 1991, having operated on three children, Mattox and Carson ¹³ published the description of a transpalatal approach to the sella turcica region that, although preserving the nasal mucosa, required a large palatectomy involving the entire hard palate. In an article from 1995, Rose-Innes and Oosthuizen ¹⁴ described a technique similar to ours in some ways, yet different in many others. Recent publications have addressed preliminary cadaveric studies and clinical trials of robotic-assisted surgery using the transoral and transpalatal corridor for skull-base surgery, including surgery on sellar tumors. ^{15 16 17}

The unfavorable evolution of the transpalatal approach for pituitary surgery probably stemmed from limitations in diagnostic methods and a lack of suitable surgical equipment (microscope, endoscope, and other devices) and microinstruments, but the multidisciplinary nature of the access route was also a factor. Over the course of around 25 years, we have successfully used and improved a microsurgical transpalatal method to access pituitary gland and skull-base tumors of the ethmoid–sphenoid–clivus region. In this method, a straight tunnel is dissected through the medial bone structures, the posterior third of the hard palate, vomer, sphenoid sinus, and floor of the sella turcica, without separating or splitting the soft palate, while preserving the integrity of the nasal mucosa and inflicting minimal damage to the local anatomy. In adults, we have opened up tunnels of approximately 20 mm in diameter and 40 to 50 mm in length—half the extension required by traditional transsphenoidal hypophysectomy, but sufficient to perform safe, efficient, and fairly conservative anatomic microsurgery with minimal bleeding. We believe this transpalatal approach will prove useful in future endoscopic and robotic-assisted intracranial interventions.

Objective

To describe a new technique for transpalatal hypophysectomy as an option for sellar region surgery using a microscope and/or an endoscope.

Anatomical Review

Anatomical and literature reviews ^{18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35} were conducted, as well as studies on corpses and surgical observations of mucosae, blood vessels, and bone and nervous structures of the hard and soft palates and nasal septum, extending to the opening of the sphenoidal sinus and sella turcica.

The anterior two-thirds of the hard palate is formed by the maxillary palatine processes (processus palatinus maxillae ) and its posterior one-third by the horizontal blades of the palatine bones (pars horizontalis ossis palatini). On each side, muscles of the soft palate attach to the aponeurosis of the posterior edge of the hard palate: in the middle, the small uvular muscle; on the sides, the palatopharyngeus muscle. The junction of the palatine processes of the maxilla and of the palatine bones in the midline and directed towards the nasal fossa, forms the nasal crest where the blade of vomer articulates and merges. The vomer, the predominant osseous structure of the lower portion and posterior third of the nasal septum, comprises a perpendicular blade and two wings (ala vomeris). The wings overlap with the sphenoidal crest at the antero-inferior wall of the sphenoidal sinus up to the rostrum, the postero-inferior limit of the sphenoid body. The sphenoidal sinus exhibits anatomical variability, according to position, size, shape, and septations, ³² and has the following anatomical and surgical relations: ethmoidal sinus anterior, clivus posterior, sella turcica above, vomer wings below, and laterally, in the postero-anterior direction from top to bottom, the internal carotid, which has an elevation in more than 80% of cases and is sometimes dehiscent. Located at the lateral wall below the internal carotid, also from top to bottom, are the abducens, maxillary, and vidian nerves. ^{30 33}

The nasal fossa and oral cavity are lined with mucosa. The nasal fossa is lined with stratified squamous and respiratory-type pseudostratified columnar ciliated epithelium containing an abundance of goblet cells. The hard palate is covered by a thick stratified squamous epithelium supported by densely collagenous lamina propria and is bound to the underlying bone by relatively dense submucosal tissue containing minor salivary glands. Our surgical observations have shown thicknesses of roughly 1.0 to 1.5 mm for the septum and nasal floor mucosa, 1.0 to 1.5 mm on the hard palate midline (raphe palati), and roughly 2.5 to 3.5 mm laterally. In a pathological situation, such as acromegaly, mucosal thickening can occur. The nasal and palatal mucosae pose little resistance to sutures, compared with the skin. Hard palate shape and thickness are relatively variable. Sometimes, a hyperostosis called torus palatinus develops at the central region. Upper airway obstruction during childhood causes the palate to become ogive, horizontally smaller, and vertically larger. ¹⁹

Blood irrigation of the anterior two-thirds of the nasal septum is supplied predominantly by the anterior and posterior ethmoidal arterial branches of the ophthalmic artery originating from the internal carotid. The sphenoidal sinus receives branches from the posterior ethmoidal arteries. Each side of the posterior third of the nasal septum is irrigated by a septal branch of the sphenopalatine artery, originating from the internal maxillary artery branch of the external carotid. The sphenopalatine artery enters the nasal submucosal space through the sphenopalatine foramen, usually situated immediately behind the tail of the medium turbinate and in front of the ethmoidal crest. Its septal branch runs medially toward the sphenoid rostrum, descends on the septum at the middle of the vomer wings, and branches out; the main ramification is the nasopalatine artery, which also irrigates the lower portion of the septum and continues to the anterior palatal foramen (foramen incisivum). The postero-lateral region of the hard palate exhibits on each side the foramen palatinum major, where the palatina major artery and the palatina minor artery (branches of the descending palatine artery originating from the internal maxillary artery) pass through. An independent lesser foramen is occasionally present. The palatina major artery stretches ahead and laterally, nourishing the hard palate and gums. It forms an anastomosis with the nasopalatine artery through the anterior palatine foramen. The palatina minor artery nourishes the soft palate.

The sensitive nasopalatine (or cotunnius) nerve, which comes from a nasal branch of the trigeminal maxillary nerve, runs together with the nasopalatine artery from the sphenoid to the anterior palatine foramen, and on their septal route they form a sulcus on the vomer. ¹⁸ Palatine nerves proceeding from the sphenopalatine ganglion pass through the foramen palatinum majus, conferring sensitivity and motility to the soft palate ( Fig. 1A, B ).

Fig. 1.

Surgical anatomy. ( A ) The nasal midline and ( B ) palate, with schematic structures, vascular nutrition, and innervation–namely, ss: sphenoidal sinus; av: ala vomeris; pbv: perpendicular blade of vomer; hp: hard palate and nasal crest; ppm: processus palatinus maxillae; phop: pars horizontalis ossis palatini; mps: midpalatal suture; tps: transverse palatine suture; fpm: foramen palatinum major; fi: foramen incisivum; aea: anterior ethmoidal artery; pea: posterior ethmoidal artery; npa: nasopalatine artery; npn: nasopalatine nerve; pma: palatina major artery; pmia: palatina minor artery; pmn: palatinus major nerve. ( C ) The palate entry zone (∼20 mm × ∼20 mm). ( D ) Comparison with classical transsphenoidal hypophysectomy: the transpalatal corridor is half as long and aligns with the bottom of the tumor. (Courtesy of Dr. Ilton Guenhiti Shinzato, PhD).

We measured the distance between the medial border of the right and left foramen palatinum major in 41 male and female skulls. Measurements ranged from 26 to 38 mm (mean, 30 mm). Because the medial–posterior part of the hard palate, up to its limit with the soft palate, is not traversed by nerve branches or major arteries, it serves as a suitable region for a palatectomy—the “palate entry zone” to reach the sphenoid sinus and the sella turcica through the bilateral submucosa of the vomer blade ( Fig. 1C, D ).

Patient Selection

We only selected patients with hypophysis macroadenomas (> 1 cm) presenting with optic chiasm compression and/or important hormonal disturbances who did not respond satisfactorily to clinical treatment. Most of the patients came to us with an urgent visual complaint with impending risk of blindness. Initially, we operated only on tumors examined by magnetic resonance imaging (MRI) that satisfied the classical indication criteria for transsphenoidal hypophysectomy, ³⁶ such as encapsulated tumors, preferably with intrasellar or symmetric suprasellar expansion, but exhibiting regular contours, as well as with an enlarged sella turcica. With time, we also began to operate on larger capsulated tumors with suprasellar, asymmetric, and even extra-axial expansions, regardless of sella size. We have indicated the transpalatal approach only for tumors likely to be cystic and/or of soft consistency. Informed written consent was obtained from all patients after they had received explanations about the surgical method and related risks and benefits.

Technique

Under general anesthesia and oral intubation, the patient is placed in dorsal decubitus with their head slightly extended, tilted away from the surgeon, and with the face rotated toward the surgeon, so as to provide a direct view of the hard palate from a more comfortable sitting position ( Fig. 2 ).

Fig. 2.

Positioning of patient for a right-handed surgeon using a microscope or endoscope. ( A ) The patient is placed in dorsal decubitus with a roughly 10-degree dorsal elevation, at the limit of the surgical bed and as close as possible to the surgeon. The head is not fixed and must be slightly lowered, tilted toward the patient's left side, and with their face rotated to their right side so that ( B ) the surgeon can have a direct view of the hard palate from a more comfortable sitting position.

First, the perioral and perinasal regions are subjected to antisepsis with an antigerm preparation such as chlorhexidine or iodine topic solution. A compress is placed around the mouth and nose, and the sterile surgical drape is placed over the patient, leaving only the mouth and nose uncovered. Once the surgical field is prepared, a McIvor Mouth Gag is applied to open the mouth wide and expose the hard palate. Nasal and oral cavity asepsis is performed with NaCl (0.9%) solution, and chlorhexidine, or iodine topical solutions are used for antisepsis.

Access may be hampered by palate shape and size. Wider, flatter palates are more favorable, and the ideal access is sufficiently large and symmetric to the midline. To reduce hemorrhage, an insulin needle and syringe is employed to inject 1 to 2 mL of 1:200,000 epinephrine solution into the lateral part of the hard palate and adjacent to the foramen palatinum major on both sides, taking care not to perforate or otherwise injure the palatina major artery. The central region of the soft palate is then infiltrated at its border with the hard palate with another 1 to 2 mL of solution until sufficient ischemia, or pallor is obtained in the “palate entry zone” ( Fig. 3A, B ).

Fig. 3.

Palate entry zone: details and marks. ( A ) Before and ( B ) after mucosa infiltration with epinephrine solution. ( C ) Anterior palate marks (pm) taking the fovea palatini (fp) and raphe palatini (rp) as references for the incision. ( D ) Incision lines: inverted U-shaped (anterior thin line) when midline mucosa is thick; M-shaped (thick line) for most other cases.

The two anterior angles and the middle of the incision are then marked, taking the raphe palatini as a reference for the midline and the fovea palatini as the posterior limit. The goal is to obtain a square access of approximately 20 mm × 20 mm. Based on the marks and using a surgical microscope or endoscope, an inverted U-shaped incision can be made if the anterior midline mucosa is thick (approximately 2 mm) or, otherwise, preferably an M-shaped incision. The incision baseline must coincide with the posterior limit of the hard palate ( Fig. 3C, D ).

The incision must be made carefully, never overextending laterally, so as not to sever the palatina major artery. The hard palate mucosa must be dissected toward the antero-posterior direction, up to its posterior edge. During dissection, small hemorrhages can be controlled with cotton wads wetted with epinephrine solution. For larger hemorrhages, however, hemostasis must be achieved with additional epinephrine solution infiltration and compression, rarely requiring bipolar electrocoagulation. We never use electrocautery. Coagulation of the palatina major artery or its main branches can lead to palate necrosis.

After dissection, and preferably under an optical system, an orifice is opened on the midline with a surgical diamond drill 3 to 4 mm in diameter until expose the septum and the nasal mucosae bilaterally. Two additional holes, each on one antero-lateral corner of the incision, are then made to expose the nasal mucosa. Working through these accesses with a set of straight and curved microdissectors, the nasal mucosa on each side of the vomer and on the nasal fossa floor is dissected. With a Kerrison's rongeur or a 2 to 3 mm-diameter diamond drill, the bone is cut along the incision. The bone fragment is lifted and the perpendicular vomer blade can be easily fractured. The bone fragment can either be removed or just lifted ( Fig. 4 ).

Fig. 4.

Palate entry zone incision and dissection. ( A ) Palate incision. ( B ) Dissection of oral mucosa. ( C ) Dissecting the nasal mucosa through the holes drilled on each side of the vomer and in the floor of the palatectomy area. ( D ) Lifting the bone after cutting.

As the next step, the mucosa on each side of the perpendicular vomer blade is dissected until the vomer wings (ala vomeris), which overlap with the sphenoidal crest, are exposed. Injuries to the nasal mucosa must be avoided, but a minute perforation of the septal mucosa is helpful for blood drainage at the postoperative phase. If severe ripping occurs, it should be reduced by bringing the injury edges together with Vicryl 3/0 sutures. A specially designed speculum is inserted to displace the mucosa while keeping the vomer blade centered, allowing good visualization of both vomer wings. When the vomer blade is removed, the wings have the appearance of a “ship's keel,”—the “entry zone in the sphenoidal sinus.” Viewing the surgical field under a microscope or endoscope provides a sufficiently good grasp of local anatomy, making the use of radiofluoroscopy optional. If the surgeon has chosen to preserve the vomer, the sphenoid sinus floor can be cut with a drill or a chisel around the vomer wings. Using this surgical approach, the vomer wings slightly overlap the clivus; therefore, entering the sphenoidal sinus requires cutting the wings by roughly 2 to 3 mm anteriorly from its posterior limit ( Fig. 5 ).

Fig. 5.

Vomer dissection. ( A ) Lifting the palate bone renders the vomer blade visible. ( B ) Dissection of the septal mucosa on both sides of the vomer blade and wings. ( C ) Special specula were designed. ( D ) Insertion of speculum renders the vomer wings visible, which can then be cut with a chisel or drill.

The inner part of the sphenoid sinus can now be visualized, usually with its irregular, asymmetric septum, as well as the deeper bulge of the sella turcica floor. Drilling in the same direction as the access allows removal of the sinus septum that lies along this path, thus opening up the sella turcica and exposing the tumor. In some cases, the tumor has descended into the sphenoidal sinus. The tumor capsule then receives an X-shaped incision and its content is scraped and aspirated with care. The tumor axis is usually aligned with the direction of the surgical access and its interior can be visualized. Bipolar electrocoagulation can also be employed for hemostasis to resect the solid portions of the tumor ( Fig. 6 ). For safer tumor removal, its interior can be inspected with the endoscope for the presence of eloquent structures, such as the carotid arteries laterally, or adjacent and externally of the tumor capsule, such as the optic nerves and chiasm ( Fig. 7 ).

Fig. 6.

Tumour removal with aid of microscope. ( A ) Because access route and tumor axis are in alignment, the interior of the tumor can be visualized and ( B ) curetted, ( C ) aspirated, and ( D ) coagulated, and dissected with a bipolar device. Deeper portions of solid tumors can be removed using this approach.

Fig. 7.

Tumour removal with aid of endoscope. ( A ) A case of cystic macroadenoma. ( B, C ) After dissecting the oral mucosa, an orifice is opened on the midline with a surgical diamond drill 3 to 4 mm in diameter until expose the septum and the nasal mucosae bilaterally without perforating it. ( D, E ) Two additional holes are drilled at the incision corners. Through these holes, the nasal mucosa is detached and the hard palate cut and lifted, exposing the nasal mucosa at the palate entry zone. ( F, G ) The vomer blade and wings (ala vomeris) are dissected and the sphenoidal sinus is opened up using a chisel or drill. ( H, I ) The sella turcica floor is opened up to expose the tumor aligned with the surgical corridor. This approach allows the tumor to be directly seen and dissected. It also allows access with an endoscope ( J ) for inspection and safer management of larger tumors. (The image shows the deeper portion of a cystic tumor, adjacent to the lamina terminalis.) ( K ) Synthesis: Inner-tumor hemostasis is achieved with bipolar electrocoagulation, Surgicel, and Gelfoam. Usually the vomer wings and blade are put back. ( L ) Nasal endoscopy reveals the fully preserved nasal mucosa, obviating the use of tampons and allowing the patient to breathe freely.

Disruption of the tumor capsule is rare, but owing to the risk of intracapsular hematoma or liquor fistula, the inner part of the capsule is lined with Surgicel at the end of the surgery, and the tumor is filled with Gelfoam. Because the openings on the sella turcica and sphenoidal sinus floor are small, it is seldom necessary to reconstruct the sella turcica, but this can be done, even using biological tissue glue, at the surgeon's discretion. We prefer to reuse the vomer wings placing them back over the sphenoidal sinus lined with Surgicel and filled with pressed Gelfoam. Also, bone fragments of the vomer blade are placed back pressing them between two thin plates of Gelfoam. To ensure anatomical healing, we use a straight dissector or spatula through the nostril to compress the septal mucosa towards the midline. The procedure is repeated on the other side. The palate bone flap is returned to its anatomical position over the nasal mucosa, now lined with Surgicel or with a thin plate of Gelfoam ( Fig. 8 ).

Fig. 8.

Synthesis. ( A ) The hard palate bone fragment and ala vomeris with an attached piece of the vomer blade. The white line shows the approximate original shape of the blade, only the posterior portion of which is dissected and removed. ( B ) Putting back the ala vomeris in the sphenoidal sinus filled with pressed Gelfoam. ( C ) The bone fragments of the blade are put back in place, pressed between two thin plates of Gelfoam. A straight dissector or spatula is introduced through the nostril to compress the septal mucosa toward the midline; the process is repeated on the other side. ( D ) The palate bone flap is placed into its original position over the nasal mucosa lined with Surgicel or with a thin pressed plate of Gelfoam.

Suturing is a critical step in surgery that is difficult to master and requires previous training. The palate mucosa is sutured with four or five simple Vicryl 3/0 sutures on each side, such that all the tension is applied to the lateral and antero-lateral regions. In the anterior region, where the mucosa is thinner, the suture must only maintain the edges together, with no tension applied ( Fig. 9A ). The M-shaped flap corners can be rotated medially to allow a piece of the thin tissue of the antero-medial region to be removed if there is any possibility of tearing or necrosis developing ( Fig. 9B ). In the event of ischemia shortly after suturing, the suture must be removed and reapplied. Each suture must be applied and reinforced with at least four knots and the end cut at roughly 5 mm in length to preclude slacking.

Fig. 9.

Suture technique. ( A ) Mucosa synthesis is performed with eight to ten simple sutures, four or five on each side, with emphasis on the antero-lateral and lateral regions, where most of the tension must be concentrated. Because the mucosa is relatively thin in the anterior region, sutures must serve only to maintain the edges together, without applying any tension. ( B ) In some cases, it may be convenient to resect a V-shaped piece of the antero-medial mucosa. ( C, D ) Some correction options if an oronasal fistula occurs.

Packing of the nasal fossa is not usually required. The fossa is hygienized by instilling NaCl (0.9%) solution for several days and, if necessary, a nasal decongestant can be used on the first few days. To prevent pneumoencephalus and meningitis, the patient must be emphatically prohibited from blowing their nose for at least two weeks postoperatively, and instructed to remove nasal secretions by inhaling, as if sniffing. Sneezing, if inevitable, must be done with the mouth wide open. We refer patients, not in use of a full-arch maxillary dental prosthesis, to a dentist to mold a palate protector of clear acrylic with dental anchors. The device must extend up to the posterior limit of the hard palate and have a perfect fit. Preferably, the patient should start using the palate protector a few days before surgery. During the postoperative period, use of the palate protector or dental prosthesis should commence only after the patient is fully awake. Uneven sutures and edema can impair the fit of both devices, which should be used continuously for at least one month and removed for cleansing after every meal ( Fig. 10 ). Before and after the surgery, the teeth and dental prosthesis, or palate protector, must be brushed with regular toothpaste and the mouth rinsed with chlorhexidine solution. Infected teeth and gums must be treated before the surgery can take place.

Fig. 10.

Postoperative protection of the palate and final scar. ( A ) An acrylic palate protector. ( B ) Postoperative view after the first week, with palate protector in use. ( C ) View after one month. ( D ) Healing completed, with palate protector impression still visible at the posterior limit of the hard palate.

Results

More than 50 patients with macroadenoma have been operated on using this approach and most reaped immediate benefit from the surgery, especially with regard to headaches and visual impairment. For macroadenomas without extra-axial expansions, tumor removal can be regarded as total (76.5%), since the approach afforded a direct view of the interior of the tumor capsule. In other cases, removal was partial (23.5%), as confirmed in some cases by control MRI ( Fig. 11 ). Forty-nine patients (98%) were extubated soon after surgery and were not transferred to the intensive care unit. Mean surgery duration was 3 hour 32 minute, while free feeding was restored after 2 days 6 hour. Postoperative hospitalization under neurosurgical care averaged 6 days 6 hour. Currently, use of a dental prosthesis or acrylic palate protector allows patients to eat soft foods on the same day, soon after recovering from anesthesia, and engage in free feeding the following day. Also, these devices make healing safer. Patients can breathe freely because no tampon is needed in the nasal fossa. Currently, operated patients have reported no complaints or physiological dysfunctions in the ensuing weeks, months, or years. On the first few postoperative days, a mild nasal obstruction may occur, which can be addressed with regular instillation of saline and/or decongestant solution. In the first few weeks, some patients report mild palate paraesthesia, which usually becomes asymptomatic within months. The surgical scar is almost invisible. The sutures begin to fall out after 20 days, vanishing completely after 40 days ( Fig. 10 ). The best surgery incision seems to be the M-shaped cut. Currently, complications and sequela are rare. We have had only two cases (3.9%) of oronasal fistulae, which were protected by the acrylic palatal plate before being resolved with a surgical intervention that was not overly uncomfortable for the patients. Three cases (5.9%) of avoidable meningitis occurred. No cases of severe hemorrhage occurred during the surgery. Also, no cases of liquoric fistula, visual impairment, panhypopituitarism, or severe syndrome of inappropriate antidiuretic hormone secretion were observed after the surgery. A total of 51 patients (aged 18–84 years; 28 females) underwent transpalatal hypophysectomy. Statistical descriptive analysis of presurgical status, postsurgical evolution, and clinical follow-up are shown ( Tables 1 2 3 and Fig. 12 ).

Fig. 11.

( A, B, and C ) Pre- and postoperative MRI scans of three cases of macroadenoma operated on using the transpalatal approach. ( D and E ) Postoperative MRI follow-up showing integrity of the nasal fossa. MRI, magnetic resonance imaging.

Table 1. Transpalatal Hypophysectomy Results.

N	Year	Sex	Age	Symptom	Pathology	Incision	Hours	Lesion	Protector	Tampon	Feeding	Days	Complaint 1st week	Complaint 1st month	Scar	Removal/ Recurrence	Sequela after 1 year
1	1999	m	44	VFI	Acromeg	U	6	Med	Y	Y	3	10	Medires	None	perfect	P	none
2	2000	m	35	Blind	Non-funct	U	5	Med	N	Y	14	14	Mididys	Milddys	dehisc	T	none
3	2001	f	30	VFI	Prolactin	U	5	Med	N	Y	10	10	Medires	Mildpar	perfect	P	none
4	2002	m	65	VFI	Acromeg	U	4	Mild	Y	N	7	7	Ildres	Infection	dehisc	T	mildpain
5	2003	m	65	Pain	Infection	U	3	Mild	Y	N	7	7	Milddys	None	perfect	T	(dboc)
6	2004	f	30	VFI	Prolactin	U	4	Mild	N	N	10	10	Mildres	None	perfect	T	none
7	2005	f	43	VFI	Non-funct	U	4	Med	N	N	10	10	Mildpain	Mildpain	perfect	T	mildpain
8	2006	m	26	Asthe	Prolactin	M	4	Mild	Y	N	3	7	Mildres	None	perfect	T	none
9	2006	f	39	VFI	Non-funct	M	4	Mild	Y	N	3	6	Mildres	None	perfect	T	none
10	2007	m	40	VFI	Prolactin	M	4	Mild	Y	N	3	6	Mildres	None	perfect	T	none
11	2008	f	60	VFI	Hypophy	M	4	Mild	Y	N	2	6	Mildres	None	perfect	T	none
12	2009	f	54	VFI	Non-funct	M	4	Mild	Y	N	2	7	Mildres	None	perfect	P/R	none
13	2009	m	25	VFI	Prolactin	M	3	Mild	Y	N	1	6	Hydroc	Dboc	(dboc)	T	(dboc)
14	2009	f	28	Pain	Non-funct	M	3	Mild	Y	N	2	7	Mildres	None	perfect	T	none
15	2009	f	84	VFI	Non-funct	M	4	Mild	Y	N	1	5	Mildres	None	perfect	P	(dboc)
16	2009	f	47	VFI	Non-funct	M	3	Mild	Y	N	1	5	Mildres	None	perfect	T	none
17	2009	f	39	VFI	Prolactin	M	3	Mild	Y	N	1	6	Mildres	None	perfect	P/R	none
18	2010	f	40	VFI	Prolactin	M	4	Med	Y	N	1	7	None	ildpar	perfect	T	mildpar
19	2010	f	30	VFI	Prolactin	M	3	Mild	Y	N	1	5	Mildres	None	perfect	T	none
20	2010	m	31	VFI	Prolactin	M	3	None	Y	N	1	5	Mildres	None	perfect	T	none
21	2011	m	47	VFI	Prolactin	M	4	Mild	Y	N	1	20	Mildres	Infection	perfect	T	none
22	2011	f	36	VFI	Prolactin	M	3	None	Y	N	1	5	Mildres	None	perfect	T	none
23	2011	f	70	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
24	2011	f	55	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
25	2011	f	54	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
26	2012	f	62	VFI	Non-funct	Y	3	None	Y	N	1	5	None	None	perfect	T	none
27	2012	f	70	VFI	Acromeg	Q	3	None	Y	N	1	5	None	None	perfect	T	none
28	2012	f	21	Infert	Prolactin	Q	4	Mild	Y	N	1	5	Mildres	None	fistula	T	none
29	2012	f	50	VFI	Non-funct	M	3	Mild	Y	N	1	4	None	None	perfect	T	none
30	2012	f	42	VFI	Cushing	O	3	None	Y	N	1	5	None	None	dehisc	T	none
31	2012	m	45	VFI	Non-funct	O	3	None	Y	N	1	14	None	Infection	fistula	T	none
32	2012	f	42	VFI	Acromeg	M	3	None	Y	N	1	5	None	None	perfect	T	none
33	2013	f	33	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
34	2013	m	52	VFI	Prolactin	M	3	None	Y	N	1	5	None	None	perfect	T	none
35	2013	m	36	VFI	Non-funct	M	4	None	Y	N	1	5	None	None	perfect	P	none
36	2014	m	44	VFI	Prolactin	M	3	None	Y	N	1	3	None	None	perfect	T	none
37	2014	f	20	VFI	Apoplexy	M	3	None	Y	N	1	5	None	None	perfect	T	none
38	2014	f	51	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
39	2015	m	26	VFI	Non-funct	M	3	None	Y	N	1	5	None	None	perfect	T	none
40	2015	m	43	VFI	Non-funct	M	4	None	Y	N	1	5	None	None	perfect	P	none
41	2016	m	23	VFI	Hypophy	M	4	None	Y	N	1	5	None	None	perfect	T	none
42	2016	m	57	VFI	Non-funct	M	3	None	Y	N	1	3	None	None	perfect	T	none
43	2016	m	31	VFI	Non-funct	M	3	None	Y	N	1	14	None	Infection	perfect	T	none
44	2016	m	58	VFI	Chorea	M	4	None	Y	N	1	5	None	None	perfect	P	none
45	2016	f	21	Dysme	Prolactin	M	3	None	Y	N	1	3	None	None	perfect	T	none
46	2016	m	39	VFI	Prolactin	M	4	None	Y	N	1	4	None	None	perfect	P	none
47	2017	m	18	VFI	Non-funct	M	3	None	Y	N	1	3	None	None	perfect	T	none
48	2017	f	39	VFI	Non-funct	M	3	Mild	Y	N	1	5	None	None	perfect	T	none
49	2018	f	60	VFI	Non-funct	M	4	None	Y	N	2	3	None	None	perfect	P	none
50	2018	m	45	VFI	Prolactin	M	4	None	N	N	1	3	None	None	perfect	P	<1 year
51	2018	m	52	Hydroc	Prolactin	M	4	None	N	N	1	3	Mildhem	None	perfect	P	<1 year

Note: Age (years); Complaint 1st month (main complaint or complication after one month): none, mildres (mild respiratory difficulties), medires (medium respiratory difficulties), milddys (mild dysphagia), mididys (medium dysphagia), mildpain (mild oronasal pain), mildpar (mild oronasal paraesthesia), hydroc (acute hydrocephaly), infection (palate infection or sphenoidal sinusitis and/or meningitis), mildhem (mild intracerebral hemorrhage), dboc (death by other cause); Complaint 1st week (main complaint or complication during first week); Days (postoperative days under neurosurgery care); Feeding (postoperative days until free feeding); Hours (surgery duration); Incision (surgical incision type used): U (inverted U-shaped), M (M-shaped), Y (Y-shaped), Q (question mark-shaped), O (osteoplastic M-shaped); Lesion (nasal mucosa lesion): none, mild, med (medium); m: male); N (sequential order of surgery); Name (name of patient); Pathology : acromeg (acromegaly), prolactin (prolactinoma), Cushing (Cushing's syndrome), non-funct (non-functioning adenoma), hypophy (hypophysitis), chorea (extrapyramidal movement associated), fistula (antero-medial oronasal fistula), infection (palate infection), mening (sphenoidal sinusitis and/or meningitis), apoplexy; Protector (postoperative use of palate prosthesis or protector): Y (yes), N (no); Removal/ Recurrence (tumor removal: T (total), P (partial), R (tumor recurrence with surgery); Scar (oral mucosa scar after one month): perfect, dehisc (dehiscence by antero-medial necrosis), fistula (antero-medial oronasal fistula); Sequela after 1 year (sequela or intercurrence after one year): none, mildpain (mild pain), mildpar (mild paraesthesia), fistula (antero-medial oronasal fistula), dboc (death by other cause); Sex (f: female; Symptom (main related or associated symptom justifying surgery decision): VFI (visual field impairment), blind (sudden blindness with urgent surgery), pain (headache), infert (infertility), asthe (asthenia), dysme (dysmenorrhea or amenorrhea), hydroc (hydrocephaly); Tampon (postoperative nasal tampon): Y (yes), N (no); Year (year of surgery).

Table 2. Quantitative Variable Analysis of Transpalatal Hypophysectomy.

Variable	N	Mean	SD	Min	Max
Age	51	43.08	14.81	18.00	84.00
Hours	51	3.53 (3 h 32 min)	0.67	3.00	6.00
Feeding	51	2.26 (2 d 6 h)	0.41	1.00	14.00
Days	51	6.24 (6 d 6 h)	3.31	3.00	20.00

Note: Age (years); Days (postoperative days under neurosurgery care); Feeding (postoperative days until free feeding); Hours (surgery duration); Max (maximum value); Mean (arithmetic mean); Min (minimum value); N (number of patients; 1999–2018); SD (standard deviation).

Table 3. Qualitative Variable Analysis of Transpalatal Hypophysectomy.

Variable		Quantity	%
Sex	Female	28	54.9
	Male	23	45.1
Symptom	VFI	45	88.2
	Pain	2	3.9
	Other	4	7.8
Pathology	Non-functioning	23	45.1
	Prolactinoma	18	35.3
	Acromegaly	4	7.8
	Hypophysitis	2	3.9
	Other	4	7.8
Incision	M-shaped	39	76.5
	Inverted U-shaped	7	13.7
	Osteoplastic M-shaped	2	3.9
	Question mark-shaped	2	3.9
	Y-shaped	1	2.0
Lesion	None	28	54.9
	Mild	18	35.3
	Medium	5	9.8
Protector	No	6	11.8
	Yes	45	88.2
Tampon	No	48	94.1
	Yes	3	5.9
Complaint during first week	None	28	54.9
	Mildres	16	31.4
	Medires	2	3.9
	Other	5	9.8
Complaint after one month	None	42	82.4
	Infection	4	7.8
	Mildpar	2	3.9
	Other	3	5.9
Scar	Perfect	45	88.2
	Dehisc	3	5.9
	Fistula	2	3.9
Removal/recurrence	T	39	76.5
	P	12	23.5
	P + R	2	3.9
Sequela (or intercurrence) after 1 year	None	43	84.3
	Mildpain	2	3.9
	Mildpar	1	2.0
	<1 year	2	3.9
	Dboc	3	5.9

Complaint after one month (main complaint or complication after one month): none, infection (palate infection and/or sphenoidal sinusitis and/or meningitis), mildpar (mild oronasal paraesthesia), other (mild oronasal paraesthesia, mild dysphagia, mild oronasal pain, dboc: death by other cause); Complaint during first week (main complaint or complication during the first week): none, mildres (mild respiratory difficulties), medires (medium respiratory difficulties), other (mild oronasal paraesthesia, mild dysphagia, medium dysphagia, mild oronasal pain, acute hydrocephalus, mild intracerebral hematoma); Incision (incision type used in surgery): M-shaped, inverted U-shaped, Y-shaped, osteoplastic M-shaped, question mark-shaped, Y-shaped; Lesion (nasal mucosa lesion): none, mild (some holes only) or medium (some holes and/or tears); Pathology : non-functioning (non-functioning adenoma), prolactinoma, acromegaly, hypophysitis, other (Cushing's syndrome, extrapyramidal movement associated, antero-medial oronasal fistula, palate infection, sphenoidal sinusitis and/or meningitis, apoplexy); Protector (postoperative palate prosthesis or protector): Yes/No; Removal/Recurrence (tumor removal: T, total: P, partial; R, recurrence with surgery); Scar (oral mucosa scar after one month): perfect, dehisc (dehiscence by antero-medial necrosis), fistula (antero-medial oronasal fistula); Sequela year (sequela of surgery or intercurrence after one year): none, mildpain (mild pain), mildpar (mild paraesthesia), dboc (death by other cause), <1 year (follow-up shorter than one year); Sex (female/male); Symptom (main related or associated symptom); Tampon (postoperative nasal tampon): Yes/No; VFI (visual field impairment and/or sudden blindness with urgent surgery), pain (headache), other (infertility, asthenia, dysmenorrhea, amenorrhea).

Fig. 12.

Evolution of three parameters, showing surgical technique improvement. Due to lack of experience and of appropriate instruments, palate opening proved more challenging in the first seven cases, with lesions in the nasal mucosa and greater discomfort for patients. Despite three cases of meningitis (21, 31, and 43), the evolution curves demonstrate that the technique has acquired stable routine status.

Discussion

Owing to limitations in our health institution system, not all preoperative data—and even less postoperative data—were available to us. For this reason, the present study is not a delineated clinical trial, but a prospective study portraying our reality. Visual issues : typically, patients presented with an urgent visual complaint, mostly visual field impairment, with impending risk of blindness. Because no manual or computerized visual field testing was readily available, most of our patients only underwent confrontation visual field testing and were followed up to compare pre- and postoperative data. Improvements in visual accuracy and visual field were experienced by most subjects within three days of surgery. Hormonal issue and pharmacological treatment : the preoperative hormonal profile was not available so easily at the first cases, but now it is possible to have it, even at the postoperative follow-up. Only recently, carbegoline becomes available in our health system. MRI issues : preoperative MRI scans are available at the hospital, but this is not always the case for postoperative follow-up. At least half of the patients underwent MRI one month after surgery, confirming tumor removal status (total or partial excision; Fig. 11A–C ). For monoaxial tumors, removal was almost total (preserving the capsule); for large, lobulated tumors, removal was partial. Patient well-being and life expectancy are more important than partial or total removal status per se; absence of induced morbidity or sequela is paramount. Ambulatory issues : attending postoperative appointments is typically difficult for patients. Some patients failed to return for follow-up.

The transpalatal approach provides an almost circular operative field roughly 2 cm in diameter, and the surgical access extension is reduced to approximately 4 to 5 cm, half the length required in the conventional transsphenoidal method. Because the main axis is aligned with the access ( Fig. 1D ), the interior of the tumor can be visualized, although microinstruments especially the bipolar device, needs to be longer to reach the bottom of larger tumors. The surgery maintains the integrity of vessels, nerves, mucosa, and practically all nasal fossa structures, except the third posterior portion, where the choanae, the nasal septum ending, and the tails of the medium and inferior turbinates are located. Postoperative video rhinoscopy or MRI have revealed no major lesions to the nasal fossa mucosa and structures ( Fig. 11D, E ).

Initially, we adopted the inverted U-shaped incisions ( Table 1 , cases 1–7), but dehiscence occurred at the antero-medial part of the incision for thinner mucosae. Adoption of an M-shaped incision ( Table 1 , from case 8 onwards) with more appropriate sutures precluded dehiscence cases by improving nutrition in the antero-middle region of the incision, where the mucosa is thinner, and allowing all suture tension to be applied laterally, where the mucosa is thicker. Seeking a less invasive access, we operated on a patient using a Y-shaped incision ( Table 1 , case 26). No complications ensued, but the surgical field was not as favorable. For two other patients ( Table 1 , cases 27 and 28), a question mark-shaped incision was employed; the first surgery was successful, but necrosis of the antero-medial part of the flap occurred in the second case. Attempting to further optimize the access, we operated on two patients ( Table 1 , cases 30 and 31) using an osteoplastic M-shaped technique, in which the bone flap was lifted and attached to the oral mucosa, but the approach promoted greater tension on the antero-medial mucosa, leading to dehiscence. Incision types are summarized in Table 3 .

Owing to lack of experience and of appropriate microinstruments and speculum ( Fig. 5C ), large lesions in the nasal mucosa inadvertently occurred in the first seven cases, and overall surgical difficulties affected postsurgical evolution, with subsequent complaints and sequela. In cases with few or no lesions, however, the oral and nasal mucosae healed well, with no complaints or sequela ( Table 1 , Fig. 12 ).

Patients who used a full-arch maxillary dental prosthesis had faster, more regular and safer healing. For this reason, we asked most patients (88.2%) to use a dental prosthesis or an acrylic palatal protector ( Fig. 10 ). In all cases of dehiscence and/or oronasal fistula, the patient was instructed to use a palatal protector to minimize discomfort.

Three avoidable cases of meningitis (5.9%) occurred. One patient ( Table 1 , case 21) who underwent an M-shaped incision and had normal postoperative course and perfect scar formation developed sphenoidal sinusitis and meningitis. Another patient ( Table 1 , case 31) operated on with an osteoplastic M-shaped incision developed dehiscence, sphenoidal sinusitis, and meningitis. Both were medically treated for meningitis and sphenoidal sinusitis and, using the same transpalatal approach, the sphenoidal sinus was intensively washed, revealing in both cases a fragment of surgical cotton lodged in this structure. Both patients recovered, but an oronasal fistula that remained in the second case was later treated and resolved. The third patient ( Table 1 , case 43) failed to follow our instructions on avoiding nose blowing for two weeks after surgery and developed pneumoencephalus and meningitis, both of which were subsequently treated and cured.

Two cases (3.9%) of oronasal fistula ( Table 1 , cases 28 and 31) required surgery. The fistula was found to be associated with nasal mucosa lesion. To correct both cases, a piece of fascia of the temporal muscle, held between thin plates of Gelfoam, was placed between the nasal and oral mucosa using biological tissue glue. After rotation of the mucosa, sutures were applied ( Fig. 9C, D ).

To avoid intracapsular hemorrhage and/or liquor fistula, we always perform intracapsular haemostasis with a bipolar device, lining the inside of the capsule with Surgicel and filling it with Gelfoam.

The transpalatal approach is currently safe and now the first option of choice for macroadenoma surgery in the Santa Casa/UFMS Neurosurgery Residency Program in Campo Grande, MS, Brazil. Having used a microscope in most cases, three years ago, we began using an endoscope, with clear improvement in the procedure, allowing surgeries to be performed more confidently and safely.

Conclusions

Transpalate-sphenoidal hypophysectomy aided by a microscope and/or endoscope is an effective, safe microsurgical procedure to access the sellar region for treatment of pituitary macroadenomas, including asymmetric suprasellar tumors with extra-axial expansions. The access provided by this technique is aligned with the tumor base, allowing direct visualization of its interior. Postoperative discomfort is low because pain is minimized. No nasal tampon is required. The patient can eat soon after surgery and be discharged within 3 to 5 days. The method is associated with almost no sequela. Reoperation can be performed via the same route.