Endoscopic transsphenoidal approach

Endoscopic transsphenoidal approach

The endoscopic transsphenoidal approach shown to be as effective as, if not more than, the traditional transseptal microscopic transsphenoidal surgery 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11).


Endoscopic transsphenoidal surgery is associated with higher gross tumor removal and lower incidence of septal perforation in patients with pituitary adenoma. Future large-scale prospective randomized controlled trials are needed to verify these findings 12)


The interest in endoscopic endonasal transsphenoidal surgery for the treatment of sellar and perisellar lesions is growing as a consequence of the results achieved in the past years and of the interest by patients, endocrinologists, and neurosurgeons. Furthermore, the special ability of the endoscope to offer a wider and detailed view of anatomic structures is a major advantage that increases the attention of neurosurgeons who seek less invasive procedures and better results. Most neurosurgeons performing transsphenoidal surgery, however, are not used to endoscopy, and changing from microsurgical to endoscopic technique can be difficult and even discouraging, often because of difficulties in the initial phase of the procedure.

With the purpose of helping minimize some of the difficulties, Cavallo et al., described useful tips and tricks that mainly concern familiarization with the endoscopic equipment, details of the transsphenoidal anatomy, and endoscopic skills. They stressed the steps and details that they judge most important.

They believed that by following these recommendations neurosurgeons can overcome, or even avoid, the difficulties frequently encountered transsphenoidal surgery, allowing them to safely and efficiently perform endonasal transsphenoidal endoscopic procedures 13).

Castle-Kirszbaum et al. described the skeletal, vascular and neural anatomical variations that could be encountered from the nasal phase, through the sphenoid phase, to the sellar phase of the operative exposure. A preoperative checklist is also provided 14)

see Transsphenoidal approach complications

A study assessed the long-term impact of endoscopic skull base surgery on olfaction, sinonasal symptoms, mucociliary clearance time (MCT), and quality of life (QoL). Patients with pituitary adenomas underwent TTEA (n = 38), while patients with other benign parasellar tumours who underwent an EEA with vascularised septal flap reconstruction (n = 17) were enrolled in this prospective study between 2009 and 2012. Sinonasal symptoms (Visual Analogue Scale), subjective olfactometry (Barcelona Smell Test-24, BAST-24), MCT (saccharin test), and QoL (short form SF-36, rhinosinusitis outcome measure/RSOM) were evaluated before, and 12 months after, surgery. At baseline, sinonasal symptoms, MCT, BAST-24, and QoL were similar between groups. Twelve months after surgery, both TTEA and EEA groups experienced smell impairment compared to baseline. Moreover, EEA (but not TTEA) patients reported increased posterior nasal discharge and longer MCTs compared to baseline. No significant changes in olfactometry or QoL were detected in either group 12 months after surgery. Over the long-term, expanded skull base surgery, using EEA, produced more sinonasal symptoms (including loss of smell) and longer MCTs than pituitary surgery (TTEA). EEA showed no long-term impact on smell test or QoL 15).

Endoscopic transsphenoidal approach case series.

Endoscopic transsphenoidal approach Instruments.

All endoscopic transphenoidal pituitary surgeries performed from January 1, 2015, to October 24, 2017, with complete data were evaluated in a retrospective single-institution study. The electronic medical record was reviewed for patient factors, tumor characteristics, and cost variables during each hospital stay. Multivariate linear regression was performed using Stata software.

The analysis included 190 patients and average length of stay was 4.71 days. Average total in-hospital cost was $28,624 (95% confidence interval $25,094-$32,155) with average total direct cost of $19,444 ($17,136-$21,752) and total indirect cost of $9181 ($7592-$10,409). On multivariate regression, post-operative cerebrospinal fluid (CSF) leak was associated with a significant increase in all cost variables, including a total cost increase of $40,981 ($15,474-$66,489, P = .002). Current smoking status was associated with an increased total cost of $20,189 ($6,638-$33,740, P = .004). Self-reported Caucasian ethnicity was associated with a significant decrease in total cost of $6646 (-$12,760 to -$532, P = .033). Post-operative DI was associated with increased costs across all variables that were not statistically significant.

Post-operative CSF leak, current smoking status, and non-Caucasian ethnicity were associated with significantly increased costs. Understanding of cost drivers of endoscopic transphenoidal pituitary surgery is critical for future cost control and value creation initiatives 16).


1)

The endoscopic versus the traditional approach in pituitary surgery. Frank G, Pasquini E, Farneti G, Mazzatenta D, Sciarretta V, Grasso V, Faustini Fustini M. Neuroendocrinology. 2006;83:240–248.
2)

Pure endoscopic endonasal approach for pituitary adenomas: early surgical results in 200 patients and comparison with previous microsurgical series. Dehdashti AR, Ganna A, Karabatsou K, Gentili F. Neurosurgery. 2008;62:1006–1015.
3)

Microscopic versus endoscopic transnasal pituitary surgery. Schaberg MR, Anand VK, Schwartz TH, Cobb W. Curr Opin Otolaryngol Head Neck Surg. 2010;18:8–14.
4)

Endoscopic versus microscopic trans-sphenoidal pituitary surgery: a systematic review and meta-analysis. Goudakos JK, Markou KD, Georgalas C. Clin Otolaryngol. 2011;36:212–220.
5)

Meta-analysis of endoscopic versus sublabial pituitary surgery. DeKlotz TR, Chia SH, Lu W, Makambi KH, Aulisi E, Deeb Z. Laryngoscope. 2012;122:511–518.
6)

Evaluation of trans-sphenoidal surgery in pituitary GH-secreting micro- and macroadenomas: a comparison between microsurgical and endoscopic approach. Lenzi J, Lapadula G, D’Amico T, et al. https://www.minervamedica.it/en/journals/neurosurgical-sciences/article.php?cod=R38Y2015N01A0011. J Neurosurg Sci. 2015;59:11–18.
7)

Endoscopic versus microscopic transsphenoidal surgery in the treatment of pituitary tumors: systematic review and meta-analysis of randomized and non-randomized controlled trials. Bastos RV, Silva CM, Tagliarini JV, Zanini MA, Romero FR, Boguszewski CL, Nunes VD. Arch Endocrinol Metab. 2016;60:411–419.
8)

Endoscopic versus microscopic approach in pituitary surgery. Gao Y, Zheng H, Xu S, Zheng Y, Wang Y, Jiang J, Zhong C. J Craniofac Surg. 2016;27:157–159.
9)

Resection of pituitary tumors: endoscopic versus microscopic. Singh H, Essayed WI, Cohen-Gadol A, Zada G, Schwartz TH. J Neurooncol. 2016;130:309–317.
10)

Endoscopic endonasal versus microsurgical transsphenoidal approach for growth hormone-secreting pituitary adenomas-systematic review and meta-analysis. Phan K, Xu J, Reddy R, Kalakoti P, Nanda A, Fairhall J. http://www.sciencedirect.com/science/article/pii/S1878875016310178. World Neurosurg. 2017;97:398–406.
11) , 12)

Endoscopic versus microscopic transsphenoidal surgery in the treatment of pituitary adenoma: A Systematic review and meta-analysis. Li A, Liu W, Cao P, Zheng Y, Bu Z, Zhou T. http://www.sciencedirect.com/science/article/pii/S1878875017300323. World Neurosurg. 2017;101:236–246.
13)

Cavallo LM, Dal Fabbro M, Jalalod’din H, Messina A, Esposito I, Esposito F, de Divitiis E, Cappabianca P. Endoscopic endonasal transsphenoidal surgery. Before scrubbing in: tips and tricks. Surg Neurol. 2007 Apr;67(4):342-7. Review. PubMed PMID: 17350397.
14)

Castle-Kirszbaum M, Uren B, Goldschlager T. Anatomical Variation for the Endoscopic Endonasal Transsphenoidal Approach. World Neurosurg. 2021 Oct 2:S1878-8750(21)01456-X. doi: 10.1016/j.wneu.2021.09.103. Epub ahead of print. PMID: 34610448.
15)

Rioja E, Bernal-Sprekelsen M, Enriquez K, Enseñat J, Valero R, de Notaris M, Mullol J, Alobid I. Long-term outcomes of endoscopic endonasal approach for skull base surgery: a prospective study. Eur Arch Otorhinolaryngol. 2015 Dec 19. [Epub ahead of print] PubMed PMID: 26688432.
16)

Parasher AK, Lerner DK, Glicksman JT, et al. Drivers of In-Hospital Costs Following Endoscopic Transphenoidal Pituitary Surgery [published online ahead of print, 2020 Aug 24]. Laryngoscope. 2020;10.1002/lary.29041. doi:10.1002/lary.29041

Anterior transpetrosal approach

Anterior transpetrosal approach

see Anterior petrosectomy.

In 1985Takeshi Kawase from the Department of Neurosurgery, Keio University School of Medicine, Tokyo, and Ashikaga Red Cross Hospital, AshikagaJapan 1) published an anterior petrosal approach to expose the posterior cranial fossa and to minimize retraction of the temporal lobe for upper petroclival


Anterior subtemporal and transpetrous apex approaches let us some exposure of deep region, however they require an unacceptable temporal lobe retraction and provide an extremely narrow surgical corridor in cases of large tumors mainly located in the infratentorial space 2) 3).

This approach requires epidural subtemporal procedures to expose the petrous apex adequately. The petrous apex must be totally resected and the dura of the temporal lobe and posterior fossa is then cut to ligate the superior petrosal sinus and tentorium. In this procedure, the most important things are to preserve the internal carotid artery (C2 segment) and greater superficial petrosal nerve (GSPN). To identify the GSPN, facial nerve integrity monitor (Medtronic Inc, Dublin, Ireland) is very useful. In the extradural bone removal, Sonopet Ultrasonic Aspirator (Stryker Ltd, Portage, Michigan) is a very excellent surgical tool for avoiding the injury of the internal carotid artery. As demonstrated by Cavalcanti, ATPA is particularly useful for accessing lesions located in the upper ventral pons via the supratrigeminal zone because it provides a wide and shallow surgical field above the trigeminal nerve without requiring retraction of the cerebellum 4).


Several neurosurgeons still have difficulty with removing tumors through an anterior petrosal approach, because a complete understanding of the Kawase pyramid has not been achieved. Jung et al. hypothesized that if anterior petrosectomy is performed with a three-dimensional understanding of the Kawase pyramid, it would have a positive effect on the extent of tumor resection.

They performed a retrospective study of patients who underwent surgical treatment for meningioma through an anterior petrosal approach. Patients were divided into total resection and subtotal resection groups, and statistical differences between the two groups were analyzed. To identify factors predictive of complete tumor removal, univariable and multivariable logistic regression analyses were performed.

The width and height of the drilled internal acoustic canal (IAC) of the total resection group were significantly longer than those of the subtotal resection group (p=0.001, p=0.033). The operative angle of the total resection group was significantly larger than that of the subtotal resection group (p<0.001). Regression analyses showed only drilled IAC width to be predictive of complete tumor removal, increasing the likelihood thereof by 2.778-fold with an increase in drilled IAC width by 1 mm (p=0.023).

Insufficient petrosectomy during an anterior petrosal approach adversely affects the extent of tumor resection. Furthering a three-dimensional understanding of the Kawase pyramid could help complete tumor resection and better outcomes without causing damage to the surrounding organs 5).


see Anterior transpetrosal transtentorial approach.

see Anterior transpetrosal approach indications.

A study of Shibao et al., included 126 patients treated via the ATPA. The bridging vein (BV) and the tentorial sinus (TenS) located in the operative fields were analyzed. Furthermore, in the preoperative evaluation, the cross-sectional shapes of the intradural vein and the interdural sinus were analyzed by curved planar reconstruction (CPR), and the flattening rate was calculated. Flattening rate = (a-b)/a = 1-b/a (a: long radius, b: short radius).

Seventeen BVs and 18 TenS were identified. The bridging site was divided into two groups: tentorial and middle fossa. The middle fossa group was divided into three subgroups: cavernous sinus, middle fossa dural sinus, and middle fossa dural adherence. Five isolated TenS were sacrificed and no venous complications were observed. The mean flattening rate was 0.13 in the intradural vein and 0.51 in the interdural sinus, respectively (P = 0.0003).

They showed classification of the BV, and preservation of the BV and TenS during the ATPA. Furthermore, they found that the interdural sinus was significantly flatter than the intradural veins. Measuring the flattening rate by CPR may be useful to identify BVs preoperatively 6).


1)

Kawase T, Toya S, Shiobara R, Mine T. Transpetrosal approach for aneurysms of the lower basilar artery. J Neurosurg. 1985 Dec;63(6):857-61. PubMed PMID: 4056899.
2)

Bambakidis NC, Gonzalez LF, Amin‐Hanjani S, et al: Combined skull base approaches to the posterior fossa. Technical note. Neurosurg Focus 19:E8, 2005
3)

Yang J, Ma SC, Fang T, et al: Subtemporal transpetrosal apex approach: study on its use in large and giant petroclival meningiomas. Chin Med J (Engl) 124:49‐55, 2011
4)

Yokoyama K, Kawanishi M, Sugie A, Yamada M, Tanaka H, Ito Y, Yamshita M. Microsurgical Resection of a Ventral Pontine Cavernoma via Supratrigeminal Zone by Anterior Transpetrosal Approach: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2018 Jul 19. doi: 10.1093/ons/opy177. [Epub ahead of print] PubMed PMID: 30032310.
5)

Jung IH, Yoo J, Roh TH, Park HH, Hong CK. Importance of sufficient petrosectomy in an anterior petrosal approach relightening of the Kawase pyramid. World Neurosurg. 2021 May 15:S1878-8750(21)00712-9. doi: 10.1016/j.wneu.2021.05.017. Epub ahead of print. PMID: 34004357.
6)

Shibao S, Toda M, Fujiwara H, Jinzaki M, Yoshida K. Bridging vein and tentorial sinus in the subtemporal corridor during the anterior transpetrosal approach. Acta Neurochir (Wien). 2019 Feb 23. doi: 10.1007/s00701-019-03857-w. [Epub ahead of print] PubMed PMID: 30798482.

Brainstem cavernous malformation approach

Brainstem cavernous malformation approach

The facial colliculus (FC), an important landmark for planning a surgical brainstem cavernous malformation approach (BCM), it may be difficult to identify on magnetic resonance imaging (MRI). Three-dimensional (3D) images may improve the FC-identification certainty; hence, a study attempted to validate the FC-identification certainty between two-dimensional (2D) and 3D images of patients with a normal brainstem and those with BCM. In this retrospective study, Uchida et al. included 10 patients with a normal brainstem and 10 patients who underwent surgery for BCM. The region of the FC in 2D and 3D images were independently identified by three neurosurgeons, three times in each case, using the method for continuously distributed test results (0-100). The intra- and inter-rater reliability of the identification certainty was confirmed using the intraclass correlation coefficient (ICC). The FC-identification certainty for 2D and 3D images was compared using the Wilcoxon signed-rank test. The ICC (1,3) and ICC (3,3) in both groups ranged from 0.88 to 0.99; therefore, the intra- and inter-rater reliability were good. In both groups, the FC-identification certainty was significantly higher for 3D images than for 2D images (normal brainstem group; 82.4 vs. 61.5, P = .0020, BCM group; 40.2 vs. 24.6, P = .0059 for the unaffected side, 29.3 vs. 17.3, P = .0020 for the affected side). In the normal brainstem and BCM groups, 3D images had better FC-identification certainty. 3D images are effective for the identification of the FC 1).

The anterior portion of mesencephalus and the interpeduncular fossa tissue may be accessed via subtemporal and retrosigmoidal approach to the posterior portion.

Supracerebellar infratentorial approach for brainstem cavernous malformation.

Lateral inferior cerebellar peduncle approach

Retrosigmoid approach

de Aguiar et al., preferred the retrosigmoid approach because it is more used due to the best view to the safety entry zones. 2).

Endoscopic endonasal surgery for a mesencephalic cavernoma 3).


1)

Uchida T, Kin T, Koike T, Kiyofuji S, Uchikawa H, Takeda Y, Miyawaki S, Nakatomi H, Saito N. Identification of the Facial Colliculus in Two-dimensional and Three-dimensional Images. Neurol Med Chir (Tokyo). 2021 May 11. doi: 10.2176/nmc.oa.2020-0417. Epub ahead of print. PMID: 33980777.
2)

de Aguiar PH, Zicarelli CA, Isolan G, Antunes A, Aires R, Georgeto SM, Tahara A, Haddad F. Brainstem cavernomas: a surgical challenge. Einstein (Sao Paulo). 2012 Jan-Mar;10(1):67-73. PubMed PMID: 23045829.
3)

Enseñat J, d’Avella E, Tercero A, Valero R, Alobid I. Endoscopic endonasal surgery for a mesencephalic cavernoma. Acta Neurochir (Wien). 2014 Oct 24. [Epub ahead of print] PubMed PMID: 25342085.
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