Key-words: Endoscopic endonasal approach introduction - planum sphenoidale - tuberculum sellae
Introduction
Tuberculum sella and planum sphenoidale meningiomas represent 5%–10% of intracranial meningiomas and arise from tuberculum sella and planum sphenoidale of anterior skull base region.[[1 ]] Tuberculum sellae meningiomas are located in close proximity of optic chiasma and thus play a significant role in vision impairment. On the other hand, planum sphenoidale meningioma is located more anterior and in proximity of the olfactory groove location.
The mean age at diagnosis is in the fourth decade, and women are more affected by this pathology. Due to the constant anatomical relationship of these tumors with the optic nerves, there is a classic presentation of these tumors represented by the chiasmal syndrome, a primary optic atrophy with bitemporal field defects in adult patients with a radiologically normal sellae. Surgical decompression is the mainstay of treatment.[[2 ]]
In this study, we have presented our surgical experience in the treatment of eight patients with tuberculum sellae and planum sphenoidale meningiomas using endoscopic endonasal transsphenoidal approach.
Materials and Methods
We retrospectively analyzed eight cases of anterior fossa meningioma specific to tuberculum sella and planum sphenoidale origin, who underwent endoscopic endonasal transsphenoidal (transtubercular-transplanum) approach between 2015 and 2018 at the Neurosurgery Department of Combined Military Hospital, Dhaka, Bangladesh. We excluded those cases who underwent craniotomy, large tumor extending beyond midpupillary line. Indications for endoscopic approaches were tumors situated on the midline with or without extension into the optic canal and vessel encasement. All the patients in the study group had been examined preoperatively with computed tomography (CT) and Magnetic resonance imaging (MRI) studies. We considered tuberculum sellae meningiomas the ones located on the small surface between the chiasmatic sulcus and diaphragma sellae and planum sphenoidale meningioma, the ones localized more anteriorly near to the olfactory groove location. Ophthalmological and endocrinological evaluations had been done both preoperatively and postoperatively.
Surgical steps
The procedure was done under general anesthesia with orotracheal intubation. Patient was placed in supine position and head was fixed by Mayfield head clamp tilting to the left, and the torso was elevated gently. Fascia lata and free fat graft being prepared from the thigh. The patient together with the endoscopic/video camera equipment being draped with aseptic techniques. The nasal cavity was prepared with adrenalin (1:1000) soaked cottonoids for at least 5 min to decrease bleeding. Preoperatively, we assessed the state of hyperostosis by CT scan to anticipate the use of high-speed drill. We used 4-mm rigid endoscopes with 0° and 30° angled lenses using both nostrils. Surgical corridor was created by doing middle turbinectomy, creation of Hadad flap with the removal of both posterior bony septum and anterior cartilaginous septum, shoulder osteotomy, and removal of vomer.
Skull base defect reconstruction was done with fat, fascia lata, nasoseptal flap, and reinforced with platelet-rich fibrin.
Postoperative management
Patients were electively kept in critical care center for postoperative management. Hourly urine output to rule out diabetes insipidus. Biochemical and endocrine review was done for electrolytes, serum osmolality, and pituitary hormone profile.
Follow up protocol
Clinical, endocrinological, and radiological follow-up was done initially 3 monthly and 6 monthly for 2 years and then every yearly to rule out any recurrence.
Results
[[Table 1 ]] shows the distribution of the age group of 8 patients with ages between 31 and 64 years.
Table 1: Distribution of age
In [[Figure 1 ]], we observed greater prevalence in women than men.
Figure 1: Distribution of sex
As shown in [[Table 2 ]], we put the preoperative radiological findings.
Table 2: Radiological findings
As shown in [[Figure 2 ]], the outcome of visual disturbances was analyzed, improved in four cases, in three cases, the visual deficit remained constant, and in one case the visual deficit worsened postoperatively.
Figure 2: Distribution of outcome of visual disturbances
Resection status of tumor revealed complete resection of tumor in six cases and subtotal resection in two cases, as shown in [[Figure 3 ]].
Figure 3: Distribution of resection status
In [[Table 3 ]], we found the post of complications with nasal complications including encrustation, synechiae, and anosmia found in four cases, two patients developed cerebrospinal fluid (CSF) leak that was managed conservatively, a tumor recurrence in one and transient DI in one case.
Table 3: Distribution of post op complications
Case illustration
In [[Figure 1 ]], it was observed that male patient (5) was more than female patient (3). A 35-year-old nonpregnant female having gradual impairment of vision in both eyes for 6 months. Visual field analysis revealed complete vision loss in the right eye and up to finger count in the left eye [[Figure 4 ]]a, [[Figure 4 ]]b, [[Figure 4 ]]c, [[Figure 4 ]]d. MRI of the brain with contrast revealed tuberculum sella and planum sphenoidale meningioma severely compressing the optic chiasm [[Figure 5 ]]a, [[Figure 5 ]]b, [[Figure 5 ]]c, [[Figure 5 ]]d. Endoscopic endonasal transtubercular-transplanum removal tumor was done [[Figure 6 ]]a, [[Figure 6 ]]b, [[Figure 6 ]]c.
Figure 4: Ophthalmological illustration, preoperative (a and b) and postoperative (c and d)
Figure 5: Radiological illustration of a case of a tuberculum-planum meningioma, preoperative (a and b) and postoperative (c and d)
Figure 6: Intraoperative removal of tumor (a and b) and reconstruction of skull base defect (c)
Discussion
Tuberculum sella and planum sphenoidale meningioma present a frequently encountered pathology of the anterior skull base that gives rise to an early visual pathology with relatively slow progression, but due to the fact that other symptoms are missing or are subtle, they have a larger tendency to develop undiagnosed for longer periods of time.[[3 ]],[[4 ]]
In our study, we have included both tuberculum sellae and planum sphenoidale meningiomas as the anatomical landmarks are very close to each other, they displace the optic apparatus in a similar fashion and were operated with the same endoscopic endonasal technique. Although there is some limitation of the surgical corridor through endoscopic endonasal transsphenoidal approach, removal of medial portion of lesser wing and anterior clinoid process increase the exposure and surgical freedom of the expanded endonasal approach.[[5 ]]
There are cases described in the literature of tuberculum sellae meningiomas misinterpreted as pituitary macroadenomas, but this was not the case in our study.[[6 ]]
Out of the eight cases operated, four cases presented an improvement of the visual acuity while in three cases the visual acuity remained stable, overall this results in a stabilization of the preoperative visual acuity in over 88% of the treated cases, a percentage that is in accordance with endoscopic resection presented in the literature.[[7 ]],[[8 ]]
Complete tumor removal was achieved in 75% of cases, which is well between the described 56%–100% margins found in the literature.[[9 ]]
CSF leak and recurrence of the tumors were low, and we believe this is due to the relatively small number of patients included in the study.
Studies have shown that patients treated through extended endoscopic approaches might benefit from better rates of complete surgical resection, and visual outcome with preservation of olfaction, less CSF leakage with visual improvement.[[10 ]]
Conclusion
As per literature, endoscopic endonasal transsphenoidal resection can be considered as a standard surgical option of tuberculum sella and planum sphenoidale meningioma management and visual recovery. In this study, we highlighted our experience of a very small group of patients with anterior fossa meningioma specific to tuberculum sella and planum sphenoidale origin.
