Endonasal approaches to the sellar and parasellar regions: closure techniques using biomaterials

CLINICAL ARTICLE

Endonasal approaches to the sellar and parasellar regions:

closure techniques using biomaterials

D. Locatelli & M. Vitali & V. M. Custodi & P. Scagnelli &

P. Castelnuovo & F. R. Canevari

Received: 26 November 2008 /Accepted: 25 May 2009 /Published online: 24 June 2009# Springer-Verlag 2009

Abstract

Purpose We reviewed the clinical outcomes resulting from

various closure techniques used following endoscopic endo-

nasal surgery for lesions in the sellar and parasellar regions.

We compared our current closure technique, which uses a

biological matrix of native equine collagen (TissuDura) fixed

with fibrin sealant (Tisseel), with the technique we employed

previously, using autologous materials, in order to assess the

comparative efficacy and tolerability of both methods over the

medium- to long-term.

Methods A review was conducted of all cases of endonasal

endoscopic intervention carried out in our institution

between 1997 and 2007. Operations performed between

January 1st 1997 and December 31st 2003 involved a sellar

closure technique using autologous materials, either alone

or supported by fibrin sealant. From January 1st 2004,

sellar reconstruction techniques involving resorbable heter-

ologous materials were used in the closure phases. Post-

operatively, clinico-endoscopic assessments took place at

15 days, 1, 3, and 6 months and yearly thereafter,

supplemented by magnetic resonance imaging (MRI) scan-

ning at 3 months and annually.

Results Between January 1st 1997 and December 31st

2003, 79 operations were performed in which the sellar

closure technique involved the use of autologous materials.

Between January 1st 2004 and January 1st 2008, 125

operations were performed in which biomaterials were used

for sellar closure. The incidence of complications (fluid

fistula) was 2.5% in the autologous materials closure group

and 1.6% in the biomaterials closure group. The most

marked difference between the two approaches was seen at

1-month follow-up, when restoration of mucociliary trans-

port in the sphenoidal sinus and physiological functionality

of the nasal mucosa and paranasal sinuses were observed to

be superior in the biomaterials patient cohort.

Conclusions The development of biomaterials for closure

of the sellar floor offers a viable alternative to traditional

techniques using autologous materials.

Keywords Endonasal endoscopic surgery .

Pituitary neoplasm . Fibrin sealant . Biomaterials .

Diving technique

Introduction

Endonasal endoscopic surgical approaches for the treatment

of sellar and parasellar lesions were introduced in the early

1990s. In 1993, Jho and Carrau first described a mono-

lateral trans-sphenoidal endonasal endoscopic approach to

the sella turcica [11, 12]. Subsequently, the endonasal

Acta Neurochir (2009) 151:1431–1437

DOI 10.1007/s00701-009-0428-9

D. Locatelli (*) :M. Vitali :V. M. Custodi

Department of Neurosurgery, IRCCS Policlinico S. Matteo,

University of Pavia,

27100 Pavia, Italy

e-mail: [email protected]

P. Scagnelli

Department of Neuroradiology, IRCCS Policlinico S. Matteo,

University of Pavia,

Pavia, Italy

P. Castelnuovo

Department of ENT-Surgery, University of Varese,

Varese, Italy

F. R. Canevari

Department of ENT-Surgery, IRCCS Policlinico S. Matteo,

University of Pavia,

Pavia, Italy

endoscopic technique was further developed in Italy by de

Divitiis and Cappabianca (Naples), by Frank and Pasquini

(Bologna) and by Locatelli and Castelnuovo (Pavia) who

introduced the ‘four-hands’ bilateral endonasal endoscopic

approach, which involves two key surgeons [2, 4, 5, 7, 8].

Based on Hardy’s classical description of the trans-

sphenoidal approach, most neurosurgeons have used fascia

lata, muscle or fat packing supported by a piece of nasal

cartilage or bone to reconstruct the pituitary sella and

prevent postoperative cerebrospinal fluid (CSF) rhinorrhoea

[10, 20]. The techniques used to achieve this are manifold,

and well-described in the current literature. Many authors

now use autologous materials, such as fat, muscle and

fascia lata, combined with the application of fibrin sealant,

to close the repair. In some cases, cartilaginous, bony,

alumina ceramic plate, silicon plate and titanium plate

grafts have been used to keep closure materials in place [1,

9, 15, 16]. However, according to Seiler and Mariani [20],

the use of such supportive materials is no longer necessary

due to the option of using fibrin sealant. These authors

further propose that autologous tissues may be replaced by

resorbable synthetic materials without increasing the inci-

dence of CSF leaks or risk of transmitting infectious

diseases [3, 13, 14, 20, 21].

Kassam et al. [13] reported data that show complete

success with the use of fibrin sealant, comparing a group of

patients in whom this material was used to a group of

subjects in whom the closure of surgical lesions was carried

out using autologous materials. Over a follow-up period

lasting a minimum of 3 years, no post-operative complica-

tions, either major or minor, were observed in the fibrin-

glue group. In contrast, the incidence of CSF fistulas in the

autologous materials group ranged between 4 and 16%,

depending on the surgical approach used. Cappabianca et

al. [3] described the use of a collagen biomatrix as a dural

substitute in 15 patients, with excellent results (only one

case of post-operative CSF fistula).

In performing conventional microscopic approaches to

the sella, either endonasal or sublabial, Couldwell et al. [6]

proposed that routine closure or reconstruction of the sella

turcica is unnecessary after trans-sphenoidal surgery unless

an intra-operative CSF leak is encountered. They advised

that autologous or heterologous materials in the sella may

interfere with the interpretation of post-operative images or

elicit a host reaction or infection. Seda et al. [19] advocated

the use of fibrin sealant, alternating in layers with

haemostatic material, even in cases where intra-operative

fluid loss have been documented. The results obtained by

these authors indicate that this approach is very effective,

all the more so in view of the speed of the surgical closing

procedure when glue alone is used, i.e. without the added

complication of autologous flaps or heterologous patches. It

should be noted, however, that Seda et al. [19] used lumbar

drainage in all patients, thereby increasing both the length

of time spent in hospital and the immediate post-operative

discomfort experienced by the patient.

Autologous grafts interact with the surrounding physio-

logical structures, promoting the migration of fibroblasts

and leading to complete recovery of the anatomical barrier.

Bone and cartilage offer consistent support, while the

mucosa provides the matrix for the new vascularization of

the tissues. It is very important that the lining of a nasal or

sinus cavity maintains its mucociliary transport character-

istics. Physiological structures provide the best biomatrix

even though the use of autologous tissues for closure calls

for separate surgical incisions, thereby increasing operating

times and causing additional discomfort to patients [20].

The development of new materials for closure of the

sellar floor offers a viable alternative to the traditional

techniques, with the promise of less post-operative discom-

fort for patients. A recent study by Yano et al. [22], who

experimented on animals using polyglactin acid patches

with fibrin sealant, demonstrated the excellent hydrody-

namic resistance provided by such a system, tested on

rabbit skin subjected to gradually increasing pressure.

Knopp et al. [14], in their experimental comparative study

of the use of a collagen biomatrix as an alternative to a

cadaver-derived dural graft, reported both clinical and

anatomical/pathological data that suggest that collagen

patches are more biocompatible and integrate more effec-

tively with surrounding tissue than grafts, to the extent that

they are capable of inducing the formation of new dural

membrane with the properties of the physiological dura,

without causing inflammation at the apposition site. A

recent study by Petter-Puchner et al. [18] showed that,

when used as a scaffold material in experimental spinal

cord injury in rats, equine collagen demonstrates improved

functional recovery compared with control animals, with no

adverse effects (in terms of neurocompatibility) perceived.

Objectives

This case series review critically analyses the clinical

outcomes resulting from various closure techniques used

following endonasal surgery for lesions in the sellar and

parasellar regions, executed using a completely endoscopic

technique. We compare our current closure technique,

which uses a biological matrix of native equine collagen

(TissuDura; Baxter, Vienna, Austria) fixed with fibrin

sealant (Tisseel; Baxter), with the technique we employed

previously, using autologous materials, and assess the

comparative efficacy of both methods over the medium to

long term. We also analyse the advantages of our current

technique and the biocompatibility of the biomaterials used,

describe any observed complications, and report patient

1432 D. Locatelli et al.

outcomes in terms of rhinosinusal consequences following

the operation.

Materials and methods

A review was conducted of all cases of endonasal

endoscopic intervention carried out in the Pavia Neurosur-

gery Division (IRCCS Fondazione San Matteo) between

1997 and 2007. Operations were performed using a range

of endonasal approaches, with a primary surgeon (D.L.)

working alongside an ENT specialist, using a technique we

have developed known as ‘two nostrils, four hands’ [5].

This requires the freehand use of rigid endoscopes with up

to three instruments used simultaneously by both surgeons

and inserted into both nostrils [5]. Intra-operatively, the

‘diving technique’ (a technique we developed in the late

1990s to perform intrasellar exploration) allows us to detect

microscopic CSF leaks that could lead to post-operative

fistulae. This technique uses a hydrojet to remove residual

tumour tissue, optimise haemostasis and improve upon and

confirm the extension of the surgical resection, and

ultimately to visualise micro-CSF leaks other than cavern-

ous sinus wall perforations (an accurate sellar closure is

performed in these cases) [5]. Post-operative external spinal

derivations were never used.

Closure using autologous materials

Operations performed between January 1st 1997 and

December 31st 2003 involved a sellar closure technique

using autologous materials, such as septal cartilage,

mucoperichondrium, mucoperiosteum and abdominal fat,

either alone or in combination, supported by fibrin sealant

(Tisseel) and tamponade of the sella with haemostatic

materials.

Closure using biomaterials

From January 1st 2004, various sellar reconstruction

techniques involving resorbable heterologous materials

were used in the closure phases of endonasal surgery. In

patients undergoing surgical intervention for sellar and

parasellar lesions, the sellar floor was repaired using

collagen matrix materials (TissuFleece and TissuDura;

Baxter) in combination with fibrin sealant (Tisseel).

In addition to use as an overlay, TissuFleece can be used

as a haemostatic material for intrasellar tamponade, as its

porous collagen matrix provides an ideal space for

organization and rapid absorption of coagulated material.

TissuDura is a biological matrix of equine collagen which

can be used as a dural substitute. It contains only colloidal

collagen (mainly type I) derived from the Achilles tendon

of the horse; the matrix contains 5.6 mg/cm2 of native

collagen fibrils, not chemically cross-linked, with no other

extraneous proteins [14]. The microscopic structure of this

matrix and the lack of porosity mean that it is particularly

appropriate for dural closure.

The general technique used for sellar reconstruction

using biomaterials in the cases reviewed here was as

follows: TissuDura was applied, following the physiolog-

ical structure by an underlay technique. It was applied in a

non-hydrated form, in order to reach the sphenoidal cavity

without bending in relation with the narrow spaces of the

nasal cavities, and was hydrated in situ by the blood and

washing fluid present in the cavity. The sella was then

sealed with Tisseel, and a layer of TissuFleece applied as an

overlay in its hydrated form. A wait of about 10 s after the

application of the fibrin sealant was sufficient to obtain

sealing of the cavity. We prefer not to use external lumbar

drainage and, in case of CSF fistula, we go back to the

operating field.

We used these materials in a manner designed to

optimise their physical characteristics for the purposes for

which they were being tested. Accordingly, they were used

in various combinations as follows:

1. TissuFleece + Tisseel: in cases where lesions were

small and space-occupying, with no dead space inside

the sellar cavity upon completion of ablation (because

of descent of suprasellar cisterns or sufficient volume

of residual pituitary adenoma), TissuFleece was used as

an overlay in combination with Tisseel with the aim of

sealing the intracranial and extracranial compartments.

2. TissuFleece + TissuDura + Tisseel: in cases where

lesions are larger than 1 cm after ablation, TissuFleece

was inserted in the sellar cavity to occupy the dead

space. TissuDura was applied to cover the sellar floor

with the underlay technique and sealed with Tisseel. An

overlay layer of TissuFleece was applied in some cases.

3. TissuDura + Tisseel: in some cases, in the absence of

dead space, TissuDura was applied by underlay

technique and sealed with Tisseel in order to achieve

reconstruction of various anatomical planes.

Post-operative care

Patients were discharged on post-operative day 4. All

patients took part in a clinico-radiological follow-up

programme for a minimum period of 6 months, which

consisted of the following series of evaluations:

1. Clinico-endoscopic assessment 15 days after surgery at

the minor surgery outpatient clinic, including endo-

scopic inspection of the nasal cavities, the surgical

approach and the sphenoid sinus. Any residual haemo-

Endonasal approaches to the sellar and parasellar regions: closure techniques using biomaterials 1433

static material in the sphenoid sinus was removed by

washing with isotonic solution and suction, and lysis

was performed on any forming synechias. The quality

of the nasal mucosa was assessed, as the quality of

sinusal ventilation, key to the recovery of physiological

function in the mucosa. Videos were made for

comparison with later checks, and patients questioned

on the quality of their nasal respiration, their olfactory

function, and on any sensations of discomfort they

were experiencing (pain, sensation of nasal obstruction,

hyposmia, increased nasal secretions, etc). Successive

checks were scheduled for 1, 3, 6 and 12 months

following surgery, then annually or as required. During

the 15-day and 6-month checks, patients completed a

questionnaire, developed by our ENT surgeon, assessing

rhinosinusal symptomatology, collecting information on

rhinosinusal symptoms in the immediate post-operative

period (nasal respiratory obstruction, post-operative

pain) and after 6 months (nasal respiratory obstruction,

facial pain, olfactory quality, rhinorrhoea, comprehen-

sive evaluation of nasal function, number of days before

patient resumed normal daily activities).

2. Neuroradiological checks, with magnetic resonance

imaging (MRI) or computed tomography (CT) scan-

ning of the sella turcica on the first or second day

following the operation to assess the outcome of the

surgery. MRI of the sella turcica was subsequently

carried out at 3 months and then annually.

3. Measurements of hormonal levels in blood and urine on

the first day after the operation, and further assessment

of the patient’s hormone function at the endocrinology

day-patient clinic 1 month after the operation, with

adjustment of treatment if necessary. Successive endo-

crinology outpatient assessments were made at 3 months

and then as required.

4. Examination of the patient’s field of vision, along with

an ophthalmology assessment, at 1 and 6 months, then

as required.

Results

Between January 1st 1997 and January 1st 2008, 204

endoscopic endonasal procedures were performed on severe

lesions in the sellar and parasellar regions. A range of

endonasal approaches were employed (Fig. 1). Table 1

presents the diseases that rendered endonasal endoscopic

intervention necessary.

Between January 1st 1997 and December 31st 2003, 79

operations were performed (on 39 female and 40 male

patients) in which the sellar closure technique involved the

use of autologous materials.

Between January 1st 2004 and January 1st 2008, 125

operations were performed (on 67 female and 58 male

patients) in which the use of biomaterials for sellar closure

was introduced. Of the 125 operations performed involving

biomaterials, 123 were performed with the exclusive use of

TissuDura collagen biomatrix and Tisseel fibrin sealant. In

40 cases, the space occupied by the removed sellar and

parasellar lesions was filled using TissuFleece. Only in two

cases of repeat surgery for post-operative fluid fistulas were

additional grafts of autologous material (mucoperichon-

drium) required to successfully close the wound.

Post-operative assessments

The periodic post-operative endoscopic checks revealed

good radication of the TissuDura in all cases in the

biomaterials closure group. During the first post-operative

endoscopic follow-up, all patients demonstrated partial

absorption of the closure material in the presence of crust

mixed with mucus, and minimal signs of non-ventilated

mucosa. Both groups of patients had similar results in terms

of incidence of minor and major complications and

ventilation of the nasal cavities.

From the analysis of videos of endoscopic check-ups, we

have observed a trend towards faster recovery of mucous

transport in the sphenoid sinus and earlier disappearance of

crusting (with a consequently reduced incidence of forma-

tion of synechias) in the group in which closure was

performed with biomaterials (TissuDura).

In terms of post-operative complications encountered,

two cases of fluid fistulas in both the autologous and

heterologous groups required repeat surgery. The endo-

scopic endonasal treatment of fluid fistulas (primary or

secondary) and the repair techniques employed for this

purpose have been discussed previously [17]. The inci-

dence of such complications represented 2.5% in the

autologous materials closure group and 1.6% in the

biomaterials closure group, and is commensurate with data

reported in the literature. No cases of rejection or displace-

ment of the graft were recorded. No patients complained of

Fig. 1 Surgical approaches used to carry out endonasal procedures

1434 D. Locatelli et al.

any rhinosinus discomfort which could have been linked to

the materials used for closure.

The results of a preliminary analysis of the question-

naires on rhinosinusal quality following sellar surgery are

promising. We have 70 questionnaires correctly completed

by each group (autologous vs biomaterials) at 15 days and

6 months after the operation. At the 15-day check the

majority of patients in both groups reported no nasal

symptomatology, with 49/70 (70%) in the autologous group

and 62/70 (89%) in biomaterials group reporting no

sensation of nasal obstruction or postoperative pain. At the

6-month check all the parameters assessed were virtually

unchanged or showed improvement.

Discussion

In our view, dural reconstruction constitutes a fundamental

part of transsphenoidal surgery, just as it does in traditional

craniotomy operations. Many authors consider that only

certain cases require mandate sellar reconstruction (such as

prolapse of the suprasellar cisterns, intraoperative discovery

of fluid fistulas, ablation of giant macroadenomas, and

significant bleeding in the cavernous sinus). However, in

our experience accurate sellar reconstruction allows, in all

cases, a more rapid and complete process of healing and

recovery of mucous transport in the sphenoid sinus, which

promotes an earlier resumption of the physiological

mucociliary function of the sinus.

In theory, autologous materials represent the ideal choice

for reconstruction, as they are perfectly biocompatible

and incapable of provoking an immune or inflammatory

response. They are particularly useful for the multi-layered

reconstruction of wide defects, e.g. after removal of lesions

in the anterior skull base. However, their use frequently

calls for additional incisions (e.g. an abdominal incision to

remove fat) or greater intranasal destruction, which

increases the length of the operation, the risk of post-

surgical infections, morbidity, and post-operative pain and

discomfort. Furthermore, the availability of autologous

materials is limited. For these reasons, attention has turned

to heterologous materials which can be used in closure and

which are capable of regenerating the physiological tissue

present at the closure site.

The characteristics of an ideal dural substitute are: that it

does not induce immune or inflammatory responses, is not

Jan 1997–Dec 2003 Jan 2004–Jan 2008

Pathology (macro, micro) n=79 n=125

Pituitary adenoma:

ACTH 0 10 (4, 6)

GH 2 (1, 1) 15 (14, 1)

PRL 23 (12, 11) 26 (13, 13)

Non-secreting [null cell] 39 (39, 0) 44 (41, 3)

Craniopharyngioma 7 (7, 0) 7 (7, 0)

Rathke’s cyst 3 (3, 0) 13 (10, 3)

Chordoma 0 2 (1, 1)

Other 5 8

Table 1 Types of disease trea-

ted by endonasal surgery in the

periods between January 1997

and December 2003, and Janu-

ary 2004 and January 2008

(ACTH adrenocorticotropic hor-

mone, PRL prolactin, GH

growth hormone)

Fig. 2 Drawings showing: a spontaneous sellar closure; b sellar

closure using TissuDura (sagittal view)

Endonasal approaches to the sellar and parasellar regions: closure techniques using biomaterials 1435

neurotoxic, and is capable of being absorbed quickly, while

at the same time allowing the development of a connecting

structure which permits the development of an endogenous

neodura. The material should also be safe from the point of

view of the transmission of viruses or prions, and should

not form adhesions with the surrounding tissues so as to

form a distinct anatomical plane; it should also be

impermeable, so as to ensure a waterproof closure. Finally,

it should be easy to handle, malleable, and easy to cut to a

desired and economically advantageous shape.

Of the various biomaterials available, the choice of

equine collagen matrix (TissuDura) as the preferred method

for sellar repair seemed to us to be the most advantageous,

especially in light of its intrinsic characteristics as high-

lighted in pre-clinical studies [14]. Its lamellar structure

virtually guarantees a lack of porosity with a resultant

impermeability which prevents the escape of fluid. The

presence of natural cross-links between the fibrils promotes

adhesion, the migration and proliferation of fibroblasts,

cellular differentiation and angiogenesis, particularly

when used together with fibrin sealant. TissuDura is

easy to cut, and maintains its size and shape even after

hydration. This means that patches can be tailored to fit

osteodural defects.

Our study adds support for the use of biomaterials as a

viable alternative or a useful addition (when used in

combination with autologous materials derived from the

patient) for closure of sellar interventions, with the potential

for less post-operative discomfort.

In all the operations, we chose to perform an accurate

sellar closure (which currently requires the use of bio-

materials), basing our decision on the improved recovery of

mucous transport processes due to the fact that new mucosa

is thereby transported along a linear plane, rather than being

forced to follow the complex path of an unreconstructed

sellar (see Fig. 2a, b). In our view, the consequences of a

swifter recovery of mucous transport are a more complete

recovery of the mucociliary transport system and a more

rapid resumption of sinus functions. The adaptability of

TissuDura to sellar defects makes it much easier to create

this mucous “flow” plane than would be the case using

autologous materials

We recorded no cases of rejection of the graft, nor of

displacement of the graft even in cases of marked prolapse

of the suprasellar cisterns, where the force of the fluid pulse

puts pressure on the graft. Our findings appear to endorse

the views of Seiler and Mariani [20], demonstrating that

sellar repair using heterologous materials is reliable, both in

terms of biocompatibility and effectiveness in preventing

the formation of dural fistulas. We believe that this case

series review is the largest published to date, in terms of

both the number of cases and the length of the follow-up

period.

Conclusions

In our opinion, biomaterials can be used in all patients

requiring rapid recovery of mucociliary functions in the

sphenoid mucosa, not just in cases in which sellar

reconstruction is traditionally mandated. Materials such as

TissuDura appear to have a promising role in endoscopic

basicranial surgery, due to their ease of use, demonstrably

good results in enabling physiological healing of surgical

approaches, high tolerance on the part of patients, and

relatively low cost, given that only a small patch is

generally necessary for sellar closure.

We predict further development of these materials as

endoscopic neurosurgical indications become more numer-

ous and extend to include a larger number of lesions

accessible by this route. The dimensions and locations of

amenable lesions essentially depend, with regard to

ablation, on the technical feasibility of conducting dissec-

tion of a quality comparable or superior to that which can

be achieved using conventional microscopy, on innovations

in the field of instrumentation, and on progress with regard

to closure systems. The evolving role of biomaterials in

addition to the already established use of autologous

materials, may enable endoscopy to become the technique

of first choice in many basicranial pathologies.

References

1. Arita K, Kurisu K, Tominaga A, Ikawa F, Iida K, Hama S,

Watanabe H (1999) Size-adjustable titanium plate for reconstruction

of the sella turcica. Technical Note. J Neurosurg 91(6):1055–1057

2. Cappabianca P, Alfieri A, de Divitiis E (1998) Endoscopic

endonasal transsphenoidal approach to the sella: towards func-

tional endoscopic pituitary surgery (FEPS). Minim Invasive

Neurosurg 41:66–73. doi:10.1055/s-2008-1052019

3. Cappabianca P, Esposito F, Cavallo LM, Messina A, Solari D, di

Somma LG, de Divitiis E (2006) Use of equine collagen foil as dura

mater substitute in endoscopic endonasal transsphenoidal surgery.

Surg Neurol 65(2):144–148. doi:10.1016/j.surneu.2005.08.023

4. Castelnuovo P, Mauri S, Locatelli D, Emmanuelli E, Delù G,

Guilio GD (2001) Endoscopic repair of cerebrospinal fluid

rhinorrhea: learning from our failures. Am J Rhinol 15(5):333–342

5. Castelnuovo P, Pistochini A, Locatelli D (2006) Different surgical

approaches to the sellar region: focusing on the “two nostrils four

hands” technique. Rhinology 44(1):2–7

6. Couldwell WT, Kan P, Weiss MH (2006) Simple closure

following transsphenoidal surgery. Technical note. Neurosurg

Focus 20(3):E11. doi:10.3171/foc.2006.20.3.12

7. Frank G, Pasquini E (2002) Endoscopic endonasal approaches to

the cavernous sinus: surgical approaches. Neurosurgery 50

(3):675. doi:10.1097/00006123-200203000-00059

8. Frank G, Pasquini E, Mazzatenta D (2001) Extended trans-

sphenoidal approach. J Neurosurg 95:917–918

9. Freidberg SR, Hybels RL, Bohigian RK (1994) Closure of

cerebrospinal leakage after transsphenoidal surgery: technical

note. Neurosurgery 35(1):159–160. doi:10.1097/00006123-

199407000-00027

1436 D. Locatelli et al.

10. Hardy J (1971) Transsphenoidal hypophysectomy. J Neurosurg 34

(4):582–594

11. Jho HD, Carrau RL, Ko Y (1996) Endoscopic pituitary surgery.

In: Wilkins RH, Rengachary SS (eds) Neurosurgical operative

atlas, vol 5. American Association of Neurological Surgeons, Park

Ridge, pp 1–12

12. Jho HD, Carrau RL, Ko Y, Daly MA (1997) Endoscopic pituitary

surgery: an early experience. Surg Neurol 47(3):213–223.

doi:10.1016/S0090-3019(96)00452-1

13. Kassam A, Horowitz M, Carrau R, Snyderman C, Welch W,

Hirsch B, Chang YF (2003) Use of Tisseel fibrin sealant in

neurosurgical procedures; incidence of cerebrospinal fluid leaks

and cost-benefit analysis in a retrospective study. Neurosurgery 52

(5):1102–1105. doi:10.1227/01.NEU.0000057699.37541.76

14. Knopp U, Christmann F, Reuche E, Sephernia A (2005) A new

collagen biomatrix of equine origin versus a cadaveric dura graft

for the repair of dural defects—a comparative animal experimental

study. Acta Neurochir (Wien) 147(8):877–887. doi:10.1007/

s00701-005-0552-0

15. Kobayashi S, Sugita K, Matsuo K, Inoue K (1981) Reconstruction

of the sellar floor during transsphenoidal operations using alumina

ceramic. Surg Neurol 15(3):196–197. doi:10.1016/0090-3019(81)

90142-7

16. Kubota T, Hayashi M, Kabuto M, Takeuchi H, Fuji T, Ohhashi M,

Kitabayashi M (1991) Reconstruction of the skull base using a

silicone plate during transsphenoidal surgery. Surg Neurol 36

(5):360–364. doi:10.1016/0090-3019(91)90024-4

17. Locatelli D, Rampa F, Acchiardi I, Bignami M, de Bernardi F,

Castelnuovo P (2006) Endoscopic endonasal approaches for repair

of CSF leaks: nine-year experience. Neurosurgery 58(4 Suppl 2):

ONS 246–256

18. Petter-Puchner AH, Froetscher W, Krametter-Froetscher R,

Lorinson D, Redl H, van Griensven M (2007) The long-term

neurocompatibility of human fibrin sealant and equine

collagen as biomatrices in experimental spinal cord injury.

Exp Toxicol Pathol 58(4):237–245. doi:10.1016/j.etp.

2006.07.004

19. Seda L, Camara RB, Cukiert A, Burattini JA, Mariani PP (2006)

Sellar floor reconstruction after transsphenoidal surgery using

fibrin glue without grafting or implants: technical note. Surg

Neurol 66(1):46–49. doi:10.1016/j.surneu.2005.10.021

20. Seiler RW, Mariani L (2000) Sellar reconstruction with resorbable

vicryl patches, gelatin foam, and fibrin glue in transsphenoidal

surgery: a 10-year experience with 376 patients. J Neurosurg 93

(5):762–765

21. Van Velthoven V, Clarici G, Auer LM (1991) Fibrin tissue

adhesive sealant for the prevention of CSF leakage following

transsphenoidal microsurgery. Acta Neurochir (Wien) 109(1–

2):26–29. doi:10.1007/BF01405692

22. Yano S, Tsuiki H, Kudo M, Kai Y, Morioka M, Takeshima H,

Yumoto E, Kuratsu J (2007) Sellar repair with resorbable

polyglactin acid sheet and fibrin glue in endoscopic endonasal

transsphenoidal surgery. Surg Neurol 67(1):59–64. doi:10.1016/j.

surneu.2006.05.049

Endonasal approaches to the sellar and parasellar regions: closure techniques using biomaterials 1437