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Table of Contents    
COMMENTARY
Year : 2019  |  Volume : 67  |  Issue : 6  |  Page : 1456-1458

Extracapsular Resection of Noninvasive Functional Pituitary Adenomas


Department of Neurosurgery, BHIMS, Mumbai, Maharashtra, India

Date of Web Publication20-Dec-2019

Correspondence Address:
Dr. Chandrashekhar Deopujari
Department of Neurosurgery, BHIMS, Mumbai, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.273656

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How to cite this article:
Deopujari C, Bhagwat A. Extracapsular Resection of Noninvasive Functional Pituitary Adenomas. Neurol India 2019;67:1456-8

How to cite this URL:
Deopujari C, Bhagwat A. Extracapsular Resection of Noninvasive Functional Pituitary Adenomas. Neurol India [serial online] 2019 [cited 2020 Jul 11];67:1456-8. Available from: http://www.neurologyindia.com/text.asp?2019/67/6/1456/273656




The series by QingXin et al. in this issue very well describes the logically possible benefits expected from extracapsular resection of functional noninvasive pituitary adenoma.[1] The foundation of modern pituitary surgery for functioning tumors was laid by Jules Hardy from Montreal, who used magnification and illumination provided by an operating microscope for the first time to facilitate the selective radical resection of pituitary microadenomas.[2] This served the purpose of differentiating the surrounding normal parenchyma from the adenomatous tissue and thus preserving normal hormonal function. Over the years, neurosurgeons have worked on these very lines, and various new techniques have been designed keeping in mind the same goals viz. maximal safe resection, normalization of hormonal function, and avoidance of recurrence. The endoscopic endonasal approach has now become the standard of care for pituitary surgery. The rapid improvements in endoscope technology have led to a remarkable rise in its popularity, as also an attendant revolutionary change in the concepts of pituitary surgery.

The concept of a tumor pseudocapsule has been well established through the work of Oldfield and Vortmeyer.[3] The techniques of intracapsular and extracapsular resection have been designed with respect to this pseudocapsule [Figure 1] and [Figure 2]. There are numerous pros and cons to both of these techniques. Extracapsular excision allows a more complete excision of the adenoma, with superior functional hormonal normalisation, although at the cost of higher rates of the injury to the cavernous sinus, normal parenchyma, and infundibulum, as also higher cerebrospinal fluid (CSF) leak rates. For this reason, extracapsular approaches went out of favour for a long time. It may be useful to note that in cases with MRI negative microadenomas that are lateralized on bilateral inferior petrosal sinus sampling (BIPSS), the success rate of hemi-hypophysectomy may be higher than that of extracapsular resection.[4],[5],[6] This is especially true while reoperating patients with microadenoma due to the lack of normalization of hormonal levels.
Figure 1

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Figure 2

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The series by Li et al. from China [1] is a fairly large series of both endoscopic and microscopic techniques for pituitary adenoma surgery. It, however, avoids any comparison between endoscopy and microscopy group outcomes and thus does not emphasise the well-known benefits of modern high-definition endoscopic visualisation.

The technique of extracapsular excision follows a generally established pattern. The endonasal component of the procedure is usually performed with the help of an ENT colleague in our setup. Wide drilling of the sellar floor is performed between the cavernous sinuses laterally and the intercavernous sinuses anteroposteriorly. A semicircular durotomy is made, preserving the pituitary capsule. For macroadenomas, internal debulking of the tumor is then begun, followed by tumor clearance in the following zones in sequential order—anterior, inferior, lateral, and superior. This does not allow premature descent of the diaphragm sellae obscuring tumor behind. This is followed by appropriate closure and repair techniques as per the size of arachnoid defect or the magnitude of intraoperative CSF leak. Recent use of fibrin glue and vascularized nasoseptal (Haddad) flap have decreased the incidence of adverse events. In microadenomas, we follow the same sequence of separation, but after complete excision of the sellar floor, we proceed to explore the appropriate side and site of microadenoma.

The paper by Li et al.[1] recommends limited sellar floor drilling, which may not serve the purpose of total tumor clearance. The excision of the tumor en masse with the intact capsule as described by the authors may be difficult especially with soft/semi-liquid adenomas, which tend to ooze out as soon as the dura is opened.

The concept of extracapsular excision presumes gross excision of the tumor, but cannot rule out a microscopic functional remnant, which may be to the tune of 70–85% [Figure 2]A and [Figure 2]B. This has been well-established by numerous papers on the subject by Laws et al. and others.[7],[8],[9],[10],[11] This effect tends to offset the process of hormonal normalization even in the absence of gross/MRI detectable residual lesions, especially in somatotroph and corticotroph adenomas. The removal of disease close to the cavernous sinus (which is the most common location in Cushing's, that is, corticotroph microadenoma) is especially difficult since the pseudocapsule is less well-developed in this area [Figure 3]A and [Figure 3]B.
Figure 3

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The series by Li et al.[1] reports an unusually high incidence of post-op diabetes insipidus (DI) (73%), given that the routinely observed rate by us as well as many others is to the tune of 18% for temporary and 2% for permanent DI.[7],[8],[12] This high rate of DI may be attributed to a greater than usual handling of the stalk/neurohypophysis during extracapsular resection.

There is also a very high proportion of microprolactinomas among the total number of operated cases (70%) in this series.[1] This is in contradiction to our experience as well as those of others, due to a generally followed practice of medically managing microprolactinomas.[3],[7],[8] The definite indications of the surgical treatment of microprolactinomas need to be restated and better defined. The authors have inexplicably excluded patients with tumor recurrence from the series, which would be an important indicator of the success of extracapsular excision and may have an impact on their conclusions.[1]



 
  References Top

1.
Li Q, Wang W, Wang X. Various strategies of transsphenoidal pseudocapsule-based extracapsular resection in noninvasive functional pituitary adenomas and their effectiveness and safety. Neurol India 2019;67:1448-55.  Back to cited text no. 1
  [Full text]  
2.
Hardy J. Transphenoidal microsurgery of the normal and pathological pituitary. Clin Neurosurg 1969;16:185-217.  Back to cited text no. 2
    
3.
Oldfield EH, Vortmeyer AO. Development of a histological pseudocapsule and its use as a surgical capsule in the excision of pituitary tumors. J Neurosurg 2006;104:7-19.  Back to cited text no. 3
    
4.
Liu JK, Fleseriu M, Delashaw JB, Ciric IS, Couldwell WT. Treatment options for Cushing disease after unsuccessful transsphenoidal surgery. Neurosurg Focus 2007;23:E8.  Back to cited text no. 4
    
5.
Ammirati M, Wei L, Ciric I. Short-term outcome of endoscopic versus microscopic pituitary adenoma surgery: A systematic review and meta-analysis. J Neurol Neurosurg Psychiatry 2013;84:843-9.  Back to cited text no. 5
    
6.
Ciric I. Long-term management and outcome for pituitary tumors. Neurosurg Clin N Am 2003;14:167-71.  Back to cited text no. 6
    
7.
Jane JAJ, Catalino MP, Laws ERJ. Surgical Treatment of Pituitary Adenomas-Endotext-NCBI Bookshelf. In: Feingold KR, Anawalt B BA, editors. Endotext. South Dartmouth (MA): MDText.com, Inc.; 2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK278983/. [Last cited on 2019 Dec 02].  Back to cited text no. 7
    
8.
Hornyak M, Couldwell WT. Multimodality treatment for invasive pituitary adenomas. Postgrad Med 2009; 121:168-76.  Back to cited text no. 8
    
9.
Fahlbusch R, Buchfelder M, Müller OA. Transsphenoidal surgery for Cushing's disease. J R Soc Med 1986;79:262-9.  Back to cited text no. 9
    
10.
Deopujari C. Surgery for acromegaly. Neurol India 2015;63:312.  Back to cited text no. 10
[PUBMED]  [Full text]  
11.
Selman WR, Laws ER, Scheithauer BW, Carpenter SM. The occurrence of dural invasion in pituitary adenomas. J Neurosurg 1986;64:402-7.  Back to cited text no. 11
    
12.
Nemergut EC, Zuo Z, Jane JA, Laws ER. Predictors of diabetes insipidus after transsphenoidal surgery: A review of 881 patients. J Neurosurg 2005;103:448-54.  Back to cited text no. 12
    


    Figures

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