Chitosan Scaffold for Sellar Floor Repair in Endoscopic Endonasal Transsphenoidal Surgery
Chitosan Scaffold for Sellar Floor Repair in Endoscopic Endonasal Transsphenoidal Surgery
A 65 year old female participant , right handed, started with progressive bilateral visual
 loss in her temporal field, over 10 months, the participant underwent an MRI and it was found
 a sellar lesion that compressed the optic chiasm, an endoscopic endonasal transsphenoidal
 surgery was done for the resection of the lesion, using a novel bilaminar chitosan scaffold
 to assist the closure of the sellar floor. After a follow up of 2 years the participant
 returned to its normal visual function, without evidence of the sellar lesion on the
 postoperative MRI, and without complications.
Introduction This case describe the use of a novel bilaminar chitosan scaffold in the repair
 of the sellar floor after an endoscopic endonasal transsphenoidal surgery for a suspected
 hipofisary macroadenoma, the use of chitosan as a scaffold has been described in several
 preclinical studies and tested in tissue bioengineering of bone, neural tissue and soft
 tissue, in the case of bone tissue, several studies demonstrated its potential due to its
 biocompatibility, osteinductive and osteoconductive features, but there is a lack of clinical
 trials demonstrating this characteristics in the clinical setting. One of the most common
 complications for the neurosurgeons after an endoscopic endonasal transsphenoidal surgery is
 the CSF leak, depending on the technique and the reconstruction used for the sellar floor
 this complication could be presented from 5% to 75%of the cases, leading to complications
 such infections and pneumoencephalus, representing a great risk for comorbidities, longer
 recovery times and hospital costs, due to this challenges in the repair of the sellar
 floor,the investigators intent to approach the problematic with a chitosan scaffold for its
 characteristics in bone regeneration. The setting of a bioactive membrane in the defect of
 the surgery could be useful for a stronger and more suitable closure of the sellar floor.

 Case description A 65 years old female participant, right handed, came to the neurosurgery
 consultation with progressive bilateral visual loss in her temporal fields, with predominance
 in the left eye over 10 months, two weeks before her admission the participant reported a
 sudden loss of consciousness, prompting her to go to the hospital. In her clinical
 examination, the participant was alert and oriented x3, normal cranial nerves examination
 except for decrease visual acuity by 20/200 in her left eye, 20/80 in her right eye,
 bitemporal hemianopia and mild primary athropy of the optic disc in the left eye, the gait
 and the motor and sensitive examination was normal. The laboratory studies showed a LH: 0.22
 and prolactine: 53.7 .In the contrasted preoperative brain MRI, it was found a sellar lesion,
 hypointense in T1 but hyperintense in T2 signal with enhancing of the periphery after the
 infusion of gadolinium, the lesion presented extension to the sphenoid sinus, paraselar space
 without involvement of the carotids and supraselar with displacement of the optic chiasm. The
 participant underwent endoscopic endonasal transsphenoidal surgery for resection of the
 sellar lesion, under the direct visualization, the lesion appeared redish and soft with
 moderately bleeding, a sample was taken for pathology and the remaining is extracted without
 complications, then the scaffold is implanted in the site of the bone defect in the sphenoid
 sinus, due to its moldable nature, it was easily set, covering the entire extension of the
 defect, a fat graft was set in the sphenoid sinus covering the bilaminar chitosan membrane,
 then fibrin sealant was used for hemostatic control and a nasal packing was set in both
 nostrils for finalize the procedure. In the postoperative there was not complication and
 after a few days the participant was discharged with notable clinical improvement, after one
 month of follow up the participant recovered her visual acuity and the participant did not
 refer any symptom, the participant underwent a post operative brain MRI, where it is observed
 a gross total resection and good closure of the sellar floor, without signs of rejection or
 inflammation in the zone with the chitosan scaffold.

 Materials and methods for the bilaminar chitosan scaffold The bilaminar implant is constitute
 by two types of different structures, one of the membranes presents a flat-smooth structure,
 the other membrane has a tridimensional-porous structure, each of the physical-chemical
 characteristics given to the membranes, was in function of the biological effect pretended in
 the effector tissue.

 The two types of membranes, synthetized for the elaboration of the bilaminar implant, were
 elaborated with biomedical grade chitosan of medium molecular weight with 75-85% of
 deacetylation in powder presentation from the brand Sigma Aldrich®, U.S.A.

 In the case of the membrane with flat-smooth structure, it was synthetized from a chitosan
 solution at 2%, the dissolution medium was diluted acetic acid (Sigma Aldrich®, U.S.A); In
 order to acquired a suitable solubilisation, the mix was set on a magnetic stirrer for 1
 hour, posteriorly the solution was brought under the action of a sonicator at 28oc for 2
 hours, until the air bubbles formed by the stirrer were completely eliminated.

 For the membrane with the tridimensional-porous structure, it was synthetized from a chitosan
 solution at 4%, the dissolution medium was diluted acetic acid (Sigma Aldrich®, U.S.A); for a
 suitable solubilisation, the mix was set on a magnetic stirrer for 4 hours, afterward the
 solution was brought under the action of a sonicator at 28oc for 2 hours, until the air
 bubbles formed by the stirrer were completely eliminated.

 Once the solutions were elaborated, for the synthesis of the two membranes (the flat-smooth
 and the tridimensional-porous) both were set in a constant quantity of ml/cm2 in a Petri
 dish, in the case of the flat-smooth membrane, it was brought under a procedure of drying
 with 98% of humidity loss and for the tridimensional-porous, a procedure of phase separating
 was termical induced.

 When both membranes are already elaborated, it is proceed to synthetize the bilaminar
 implant, the membranes are combined using a solution of chitosan acetate at 2%, that was
 distributed uniformly between both membranes to create a sandwich structure, consecutively
 the ensemble was put in a Petri dish and the cover was set inverted in the superior aspect of
 petri dish. It was set for drying for 24 hours at room temperature and then it was
 precipitated in a solution of sodium hydroxide 1N, following the same indications used for
 each membrane separately.
Inclusion Criteria:

 -  male/female patient candidate for an endoscopic endonasal transphenoidal surgery, who
 need repair of the sellar floor as part of the surgical procedure.

 Exclusion Criteria:

 -  Diabetes, heart diseases, immunological diseases, infectious diseases, bone diseases.