Cerebrospinal fluid leaks after transsphenoidal surgery - Effect of a polyethylene glycol hydrogel dural sealant

Tissue Sealant Impact on Skull Base Reconstruction Outcomes: A Systematic Review and Meta-Analysis

OBJECTIVE

Despite significant advances in understanding of skull base reconstruction principles, the role of tissue sealants in modifying postoperative cerebrospinal fluid (CSF) leak outcomes remains controversial. We evaluate postoperative CSF leak incidence associated with tissue sealant use in skull base defect repair during endoscopic skull base surgery (ESBS).

DATA SOURCES

Web of Science, PubMed/MEDLINE, Scopus, and Cochrane Library.

REVIEW METHODS

Systematic review and meta-analysis of risk differences (RD). A search strategy identified original studies reporting CSF leakage following ESBS with disaggregation by tissue sealant use and/or type.

RESULTS

27 non-randomized studies (n = 2,403) were included for qualitative and meta-analysis. Reconstruction with a tissue sealant did not significantly reduce postoperative CSF leak risk compared with reconstruction without sealant (RD[95% CI] = 0.02[-0.01, 0.05]). Sub-analyses of dural sealant (-0.02[-0.11, 0.07]) and fibrin glue (0.00[-0.07, 0.07]) compared with no sealant were similarly unremarkable. Postoperative CSF leakage was not significantly modulated in further sub-analyses of DuraSeal (0.02[-0.02, 0.05]), Adherus (-0.03[-0.08, 0.03]), or Bioglue (-0.06[-0.23, 0.12]) versus no dural sealant use, or Tisseel/Tissucol versus fibrin glue nonuse (0.00[-0.05, 0.05]). No significant association was seen comparing dural sealant use versus fibrin glue use on pairwise (0.01[-0.03, 0.05]) or network meta-analysis (-0.01[-0.05, 0.04]). Limitations in source literature prevented sub-analyses stratified by leak characteristics, defect size and location, and accompanying reconstruction materials.

CONCLUSION

Tissue sealant use did not appear to impact postoperative CSF leak incidence when compared with nonuse. Higher quality studies are warranted to thoroughly elucidate the clinical value of adjunct sealant use in endoscopic skull base reconstruction.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2024.

Ex vivo and in vivo evaluation of transsphenoidal Liqoseal application to prevent cerebrospinal fluid leakage

BACKGROUND

Despite improvements in closure techniques by using a vital nasoseptal flap, the use of sealing materials, and improved neurosurgical techniques, cerebrospinal fluid (CSF) leak after transsphenoidal surgery still is a clinically relevant problem. Liqoseal® (Polyganics bv, Groningen, The Netherlands) is a CE-approved bioresorbable sealant patch for use as an adjunct to standard methods of cranial dural closure to prevent CSF leakage. This study aims to evaluate the application of Liqoseal in transsphenoidal surgery ex vivo and in vivo.

METHODS

1. We created an ex vivo setup simulating the sphenoidal anatomy, using a fluid pump and porcine dura positioned on a conus with the anatomical dimensions of the sella to evaluate whether the burst pressure of Liqoseal applied to a bulging surface was above physiological intracranial pressure. Burst pressure was measured with a probe connected to dedicated computer software. Because of the challenging transsphenoidal environment, we tested in 4 groups with varying compression weight and time for the application of Liqoseal. 2. We subsequently describe the application of Liqoseal® in 3 patients during transsphenoidal procedures with intraoperative CSF leakage to prevent postoperative CSF leakage.

RESULTS

1. Ex vivo: The overall mean burst pressure in the transsphenoidal setup was 231 (± 103) mmHg. There was no significant difference in mean burst pressure between groups based on application weight and time (p = 0.227). 2. In Vivo: None of the patients had a postoperative CSF leak. No nose passage problems were observed. One patient had a postoperative meningitis and ventriculitis, most likely related to preoperative extensive CSF leakage. Postoperative imaging did not show any local infection, swelling, or other device-related adverse effects.

CONCLUSIONS

We assess the use of Liqoseal® to seal a dural defect during an endoscopic transsphenoidal procedure as to be likely safe and potentially effective.

Impact of Postural Changes on Sinonasal Pressure After Endoscopic Endonasal Surgery

BACKGROUND

Postoperative management following endoscopic endonasal surgery (EES) is important to prevent cerebrospinal fluid leak and preserve the integrity of the nasoseptal flap. No consensus regarding an optimal posture in the postoperative period has been established. We hypothesized that sinonasal pressure (SNP) can represent intracranial pressure affecting the sellar floor in the absence of the sellar bone after surgery. This study provides evidence for the effect of postural changes and recommends optimal posture to reduce SNP following EES.

METHODS

The authors conducted a retrospective analysis of 50 patients who underwent reconstruction for skull base defects with nasoseptal flap after EES for resection of suprasellar tumor between March 2020 and August 2020. The Spiegelberg intracranial pressure probe was placed through the nostril over the nasoseptal flap. SNPs were measured in Fowler' (45° tilt) and supine positions, respectively, daily for the first 3 days immediately after EES.

RESULTS

For the first 3 days after surgery, the mean SNP in Fowler' position (24.82 mmHg; standard deviation, 12.23 mmHg) was lower than that in the supine position (28.42 mmHg; standard deviation, 12.33 mmHg) (P < 0.01). There were no significant differences in mean SNP for age, sex, tumor size, presence of hydrocephalus, and body mass index.

CONCLUSIONS

There was a significant correlation between Fowler' position and a decrease in SNP measurements. Placing a patient in Fowler' position after surgery can decrease the SNP. We recommend that patients should be placed in a Fowler' position as an optimal position after surgery.

Endoscopic Endonasal Skull Base Surgery Complication Avoidance: A Contemporary Review

The endoscopic endonasal approach (EEA) provides a direct trajectory to ventral skull base lesions, avoidance of brain retraction, and clear visualization of cranial nerves as they exit skull base foramina. Despite these benefits, the EEA is not without complications. Here, we review published literature highlighting complications associated with the EEA including cerebrospinal fluid (CSF) leak, cranial nerve (CN) dysfunction, pituitary gland dysfunction, internal carotid artery (ICA) injury, infection, and others; we place special emphasis on discussing the prevention of these complications. As widespread adoption of the EEA continues, it becomes critical to educate surgeons regarding potential complications and their prevention while identifying gaps in the current literature to guide future research and advances in clinical care.

Fibrin-coated collagen fleece versus absorbable dural sealant for sellar closure after transsphenoidal pituitary surgery: a comparative study

Various surgical methods to prevent postoperative cerebrospinal fluid (CSF) leaks during transsphenoidal surgery have been reported. However, comparative studies are scarce. We aimed to compare the efficacy of a fibrin-coated collagen fleece (TachoSil) versus a dural sealant (DuraSeal) to prevent postoperative CSF leakage. We perform a retrospective study comparing two methods of sellar closure during endoscopic endonasal transsphenoidal surgery (EETS) for pituitary adenoma resection: TachoSil patching versus DuraSeal packing. Data concerning diagnosis, reconstruction technique, and surgical outcomes were analyzed. The primary endpoint was postoperative CSF leak rate. We reviewed 198 consecutive patients who underwent 219 EETS for pituitary adenoma from February 2007 and July 2018. Intraoperative CSF leak occurred in 47 cases (21.5%). A total of 33 postoperative CSF leaks were observed (15.1%). A reduction of postoperative CSF leaks in the TachoSil application group compared to the conventional technique using Duraseal was observed (7.7% and 18.2%, respectively; p = 0.062; Pearson exact test) although non-statistically significant. Two patients required lumbar drainage, and no revision repair was necessary to treat postoperative CSF rhinorrhea in Tachosil group. Fibrin-coated collagen fleece patching may be a valuable method to prevent postoperative cerebrospinal fluid (CSF) leaks during EETS for pituitary adenoma resection.

Pedicled frontal periosteal rescue flap via eyebrow incision for skull base reconstruction (SevEN-002)

Purpose

Cerebrospinal fluid (CSF) leakage is one of the major complications after endoscopic endonasal surgery. The reconstructive nasoseptal flap is widely used to repair CSF leakage. However, it could not be utilized in all cases; thus, there was a need for an alternative. We developed a pericranial rescue flap that could cover both sellar and anterior skull base defects via the endonasal approach. A modified surgical technique that did not violate the frontal sinus and cause cosmetic problems was designed using the pericranial rescue flap.

Methods

We performed 12 cadaveric dissections to investigate the applicability of the lateral pericranial rescue flap. An incision was made, extending from the middle to the lateral part of the eyebrow. The pericranium layer was dissected away from the galea layer, from the supraorbital region towards the frontoparietal region. With endoscopic assistance, the periosteal flap was raised, the flap base was the pericranium layer at the eyebrow incision. After a burr-hole was made in the supraorbital bone, the pericranial flap was inserted via the intradural or extradural pathway.

Results

The mean size of the pericranial flap was 11.5 cm × 3.2 cm. It was large enough to cross the midline and cover the dural defects of the anterior skull base, including the sellar region.

Conclusion

We demonstrated a modified endoscopic technique to repair the anterior skull base defects. This minimally invasive pericranial flap may resolve neurosurgical complications, such as CSF leakage.

2D versus 3D Endoscopy: Head-to-Head Comparison in a Simulated Model of Endoscopic Endonasal Dural Suturing

Objective Endonasal dural suturing (EDS) has been reported to decrease the incidence of cerebrospinal fluid fistula. This technique requires handling of single-shaft instrumentation in the narrow endonasal corridor. It has been proposed that three-dimensional (3D) endoscopes were associated with improved depth perception. In this study, we sought to perform a comparison of two-dimensional (2D) versus 3D endoscopy by assessing surgical proficiency in a simulated model of EDS.

Materials and Methods Twenty-six participants subdivided into groups based on previous endoscopic experience were asked to pass barbed sutures through preset targets with either 2D (Storz Hopkins II) or 3D (Storz TIPCAM) endoscopes on 3D-printed simulation model. Surgical precision and procedural time were measured. All participants completed a Likert scale questionnaire.

Results Novice, intermediate, and expert groups took 11.0, 8.7, and 5.7 minutes with 2D endoscopy and 10.9, 9.0, and 7.6 minutes with 3D endoscopy, respectively. The average deviation for novice, intermediate, and expert groups (mm) was 5.5, 4.4, and 4.3 with 2D and 6.6, 4.6, and 3.0 with 3D, respectively. No significant difference in procedural time or accuracy was found in 2D versus 3D endoscopy. 2D endoscopic visualization was preferred by the majority of expert/intermediate participants, while 3D endoscopic visualization by the novice group.

Conclusion In this pilot study, there was no statistical difference in procedural time or accuracy when utilizing 2D versus 3D endoscopes. While it is possible that widespread familiarity with 2D endoscopic equipment has biased this study, preliminary analysis suggests that 3D endoscopy offers no definitive advantage over 2D endoscopy in this simulated model of EDS.

Skull base repair following endonasal pituitary and skull base tumour resection: a systematic review

PURPOSE

Postoperative cerebrospinal fluid rhinorrhoea (CSFR) remains a frequent complication of endonasal approaches to pituitary and skull base tumours. Watertight skull base reconstruction is important in preventing CSFR. We sought to systematically review the current literature of available skull base repair techniques.

METHODS

Pubmed and Embase databases were searched for studies (2000-2020) that (a) reported on the endonasal resection of pituitary and skull base tumours, (b) focussed on skull base repair techniques and/or postoperative CSFR risk factors, and (c) included CSFR data. Roles, advantages and disadvantages of each repair method were detailed. Random-effects meta-analyses were performed where possible.

RESULTS

193 studies were included. Repair methods were categorised based on function and anatomical level. There was absolute heterogeneity in repair methods used, with no independent studies sharing the same repair protocol. Techniques most commonly used for low CSFR risk cases were fat grafts, fascia lata grafts and synthetic grafts. For cases with higher CSFR risk, multilayer regimes were utilized with vascularized flaps, gasket sealing and lumbar drains. Lumbar drain use for high CSFR risk cases was supported by a randomised study (Oxford CEBM: Grade B recommendation), but otherwise there was limited high-level evidence. Pooled CSFR incidence by approach was 3.7% (CI 3-4.5%) for transsphenoidal, 9% (CI 7.2-11.3%) for expanded endonasal, and 5.3% (CI 3.4-7%) for studies describing both. Further meaningful meta-analyses of repair methods were not performed due to significant repair protocol heterogeneity.

CONCLUSIONS

Modern reconstructive protocols are heterogeneous and there is limited evidence to suggest the optimal repair technique after pituitary and skull base tumour resection. Further studies are needed to guide practice.

Heterogeneity in Outcome Reporting in Endoscopic Endonasal Skull Base Reconstruction: A Systematic Review

Objective  Presently, there are no standards for reporting outcomes of endoscopic endonasal skull base reconstruction (ESBR). This is problematic as a lack of consistent reporting makes synthesizing findings in systematic reviews and meta-analysis challenging. Thus, the aim of this study was to systematically review and describe the patterns of reporting outcomes in ESBR as a foundation for developing reporting guidelines. Study Design  Present study is a systematic review. Methods  Embase, PubMed, CINAHL, Cochrane Library, and Web of Science were searched for all publications with ≥25 patients and a focus on ESBR. The reporting patterns of each study's variables and outcomes were assessed. Results  A total of 112 studies were included in the review. The most commonly reported demographic variables were the number of included patients ( n  = 112, 100%) and types of pathologies treated ( n  = 104, 92.9%). Meanwhile, the most routinely described preoperative variable was history of prior treatment ( n  = 48, 42.9%). Type of reconstruction was a commonly reported intraoperative variable ( n  = 110, 98.2%), though the rate of intraoperative cerebrospinal fluid (CSF) leak was noted in only 76 studies (67.9%). With regard to postoperative outcomes, postoperative CSF leak rate was routinely provided ( n  = 101, 90.2%), but reporting of other surgical complications was more inconsistent. Ultimately, of the 43 variables and outcomes reviewed, a median of 12 (range: 4-22) was reported in each study. Conclusion  There is significant heterogeneity in the outcomes reported in studies relating to ESBR. This highlights the need for the development of standard reporting guidelines to minimize bias and improve interstudy comparability.

Efficacy and safety of polyethylene glycol dural sealant system in cranial and spinal neurosurgical procedures: Meta-analysis

Background:

We aimed to assess the efficacy of polyethylene glycol (PEG) dura sealant to achieve watertight closure, prevention of cerebrospinal fluid (CSF) leak and to investigate its possible side effects.

Methods:

We searched Medline (through PubMed), Scopus, and the Cochrane Library through December 2019. We included articles demonstrating cranial or spinal procedures with the use of PEG material as a dural sealant. Data on intraoperative watertight closure, CSF leak, and surgical complications were extracted and pooled in a meta-analysis model using RevMan version 5.3 and OpenMeta (Analyst).

Results:

Pooling the controlled trials showed that PEG resulted in significantly more intraoperative watertight closures than standard care (risk ratio [RR] = 1.44, 95% confidence interval [CI] [1.24, 1.66]). However, the combined effect estimate did not reveal any significant difference between both groups in terms of CSF leaks, the incidence of surgical site infections, and neurological deficits (P = 0.7, 0.45, and 0.92, respectively). On the other hand, pooling both controlled and noncontrolled trials showed significance in terms of leak and neurological complications (RR = 0.0238, 95% CI [0.0102, 0.0373] and RR = 0.035, 95% CI [0.018, 0.052]). Regarding intraoperative watertight closure, the overall effect estimate showed no significant results (RR=0.994, 95% CI [0.986, 1.002]).

Conclusion:

Dura seal material is an acceptable adjuvant for dural closure when the integrity of the dura is questionable. However, marketing it as a factor for the prevention of surgical site infection is not scientifically proved. We suggest that, for neurosurgeons, using the dural sealants are highly recommended for duraplasty, skull base approaches, and in keyhole approaches.

Creative and Innovative Methods and Techniques for the Challenges in the Management of Adult Craniopharyngioma

Craniopharyngioma remains a major challenge in daily clinical practice. The pathobiology of the tumor is still elusive, and there are no consensus or treatment guidelines on the optimal management strategy for this relatively rare tumor. However, recent technical and scientific advances, including genomic and radiomic profiling, innovation in surgical approaches, more precise radiotherapy protocols, targeted therapy, and restoration of lost functions all have the potential to significantly improve the outcome of patients with craniopharyngioma in the near future. Although many of these innovative tools in the new armamentarium of the clinician are still in their infancy, they could reduce craniopharyngioma-related morbidity and mortality and improve the patients' quality of life. In this article, we discuss these creative and innovative approaches that may offer solutions to the obstacles faced in treating craniopharyngioma and future possibilities in improving the care of these patients.

A Single Layer Synthetic Dural Substitute Inlay is an Effective Sellar Reconstruction Technique in Endoscopic Transsphenoidal Pituitary Surgery

Objectives A variety of endonasal sellar repair techniques have been described; many are complex, multilayered, and carry potential morbidity. We propose an effective, technically simple single-layer repair for select sellar defects, including those with an intraoperative cerebrospinal fluid (CSF) leak. Our technique utilizes only a synthetic dural substitute inlay and dural sealant glue without packing or lumbar drainage.

Design This is a retrospective review-based study.

Setting This study was conducted at tertiary care center.

Participants Patients who underwent endoscopic transsphenoidal surgery for pituitary adenoma and sellar reconstruction with the aforementioned inlay technique. Patients were selected for this technique if they had an identified intraoperative CSF leak, a patulous diaphragm (expanded and thinned diaphragma sella), or a comorbidity excluding them from a simpler onlay only reconstruction.

Outcome Measures Postoperative CSF leak and sinonasal morbidity included in the study

Results A total of 409 subjects were identified; 368 were initial resections. Gross total resection of the pituitary adenoma was achieved in 356 (87.0%) cases. Average tumor size was 2.6 ± 1.1 cm. Average tumor volume was 10.8 ± 12.1 cm3. There were 135 intraoperative CSF leaks and 196 patulous diaphragms. There were five postoperative CSF leaks (1.2%), all of which occurred in the first half of our series. Pre- and postoperative sino-nasal outcomes test-22 scores were 19.2 ± 18.2 and 18.8 ± 21.3 (p = 0.492), respectively.

Conclusion A synthetic dural substitute inlay and dural sealant glue is an excellent single-layer repair for sellar defects, even those with an intraoperative CSF leak. This technique is highly effective in preventing postoperative CSF leaks and does not utilize packing or lumbar drainage. It also avoids the potential cost and morbidity associated with more complex and multilayered closures.

Abdominal Fat Graft for Sellar Reconstruction: Retrospective Outcomes Review and Technical Note

BACKGROUND

The transsphenoidal approach is the standard of care for the treatment of pituitary adenomas and is increasingly employed for many anterior skull base tumors. Persistent postoperative cerebrospinal fluid (CSF) leaks can result in significant complications.

OBJECTIVE

To analyze our series of patients undergoing abdominal fat graft repair of the sellar floor defect following transsphenoidal surgery, describe and investigate our current, routine technique, and review contemporary and past methods of skull base repair.

METHODS

A recent consecutive series (2008-2017) of 865 patients who underwent 948 endonasal procedures for lesions of the sella and anterior skull base was retrospectively reviewed. Three hundred eighty patients underwent reconstruction of the sellar defect with an abdominal fat graft.

RESULTS

The diagnoses of the 380 patients receiving fat grafts were the following: 275 pituitary adenomas (72.4%), 50 Rathke cleft cysts (13.2%), 12 craniopharyngiomas (3.2%), and a variety of other sellar lesions. Fourteen patients had persistent postoperative CSF leak requiring reoperation and included: 5 pituitary adenomas (1.3%), 4 craniopharyngiomas (1.1%), 2 arachnoid cysts (0.53%), 2 prior CSF leaks (0.53%), and 1 Rathke cleft cyst (0.26%). Four patients (1.1%) developed minor abdominal donor site complications requiring reoperation: 1 hematoma, 2 wound complications, and 1 keloid formation resulting in secondary periumbilical infection.

CONCLUSION

Minimizing postoperative CSF leaks following endonasal anterior skull base surgery is important to decrease morbidity and to avoid a prolonged hospital stay. We present an evolved technique of abdominal fat grafting that is effective and safe and includes minimal morbidity and expense.

Engineered Hydrogels for Brain Tumor Culture and Therapy

Brain tumors' severity ranges from benign to highly aggressive and invasive. Bioengineering tools can assist in understanding the pathophysiology of these tumors from outside the body and facilitate development of suitable antitumoral treatments. Here, we first describe the physiology and cellular composition of brain tumors. Then, we discuss the development of three-dimensional tissue models utilizing brain tumor cells. In particular, we highlight the role of hydrogels in providing a biomimetic support for the cells to grow into defined structures. Microscale technologies, such as electrospinning and bioprinting, and advanced cellular models aim to mimic the extracellular matrix and natural cellular localization in engineered tumor tissues. Lastly, we review current applications and prospects of hydrogels for therapeutic purposes, such as drug delivery and co-administration with other therapies. Through further development, hydrogels can serve as a reliable option for in vitro modeling and treatment of brain tumors for translational medicine.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Efficacy and Safety of Intraoperative Lumbar Drain in Endoscopic Skull Base Tumor Resection: A Meta-Analysis

Objectives: This study aims to evaluate the efficacy and safety of lumbar drainage (LD) in preventing cerebrospinal fluid (CSF) leaks after endoscopic skull base tumor resection. Methods: A systematic online search was conducted using PubMed, Embase, Scopus, Web of Science, and Cochrane Library from January 2006 to July 2019. Data analyses were performed by the Cochrane Collaboration's Review Manager 5.3 software. Results: Eight studies, including two randomized controlled trials and six observational studies, met the inclusion criteria. No significant difference was found in the post-operative CSF leak rate between the LD group and the non-LD group [odds ratio (OR), 0.80; 95%CI, 0.37-1.74; I 2 = 37%; P = 0.57). Subgroup analysis of the intraoperative high-flow leaks, including 4 studies and 313 patients, showed that LD was associated with reduced likelihood of post-operative CSF leak (OR, 0.37; 95%CI, 0.17-0.83; I 2 = 0%; P = 0.02). The placement of LD was related to increased risk of headache compared with non-LD use, and no significant difference was found in the occurrence of deep vein thromboses and pulmonary emboli between two groups. Conclusion: LD is not recommended in all patients undergoing endoscopic skull base tumor resection. However, for patients with intraoperative high-flow leaks, LD is effective and safe in reducing risk of CSF leak.

Surgical applications of intracorporal tissue adhesive agents: current evidence and future development

Introduction: Traditional mechanical closure techniques pose many challenges including the risk of infection, tissue reaction, and injury to both patients and clinicians. There is an urgent need to develop tissue adhesive agents to reform closure technique. This review examined a variety of tissue adhesive agents available in the market in an attempt to gain a better understanding of intracorporal tissue adhesive agents as medical devices.Areas covered: Fundamental principles and clinical determinants of the tissue adhesives were summarized. The available tissue adhesives for intracorporal use and their relevant clinical evidence were then presented. Lastly, the perspective of future development for intracorporal tissue adhesive were discussed. Clinical evidence shows current agents are efficacious as adjunctive measures to mechanical closure and these agents have been trialed outside of clinical indications with varied results.Expert opinion: Despite some advancements in the development of tissue adhesives, there is still a demand to develop novel technologies in order to address unmet clinical needs, including low tensile strength in wet conditions, non-controllable polimerization and sub-optimal biocompatibility. Research trends focus on producing novel adhesive agents to remit these challenges. Examples include the development of biomimetic adhesives, externally activated adhesives, and multiple crosslinking strategies. Economic feasibility and biosafety are limiting factors for clinical implementation.

A Simple Onlay Sellar Reconstruction Does Not Increase the Risk of Postoperative Cerebrospinal Fluid Leak in Well-Selected Patients

Objective  A variety of endonasal sellar repair techniques have been described; many of which are complex, expensive, and carry potential morbidity but are felt to be necessary to prevent postoperative cerebrospinal fluid (CSF) leaks. We propose an effective, technically simple repair for select sellar defects utilizing an onlay of regenerated oxidized cellulose. Design  Retrospective review of patients from a single neurosurgeon who underwent endoscopic transsphenoidal surgery for pituitary adenoma and sellar reconstruction with only an onlay of regenerated oxidized cellulose. Patients were selected for this repair technique based on the absence of: (1) intraoperative identification of a CSF leak, (2) patulous diaphragm (expanded diaphragm sella herniating to or through sellar floor defect), and (3) other prohibiting comorbidities. Setting  The present study was conducted at a tertiary care center. Participants  In this study, pituitary adenoma patients were the participants. Outcome Measures  Main outcome measure of the study is postoperative CSF leak. Results  A total of 172 patients were identified. Of these, 153 were initial resections of pituitary adenomas. Gross total resection was achieved in 142 (82.6%) cases. Average tumor size was 2.2 ± 1.1 cm. Average tumor volume was 10.4 ± 19.8 cm ³ . No patients had intraoperative CSF leaks. All cases were repaired with only an onlay of regenerated oxidized cellulose. There were two postoperative CSF leaks (1.16%). Pre and postoperative SNOT-22 scores were 12.9 ± 11.9 and 14.3 ± 14.9 ( p  = 0.796), respectively. Conclusion  The use of an onlay of regenerated oxidized cellulose alone is an effective repair technique for select sellar defects. This technique does not result in increased postoperative CSF leak rates and avoids the higher relative cost and potential morbidity associated with more complex, multilayered closures.

Bioadhesives in neurosurgery: a review

OBJECTIVE

Neurosurgery presents unique surgical challenges arising from delicate neural structures, limited accessibility, and the risk of CSF leakage that can lead to CNS infections. Sutures and staples may have limited applicability in the complex anatomical constraints of cranial and spinal surgeries, especially in trauma settings when time is of the essence. Surgical bioadhesives are emerging as attractive alternatives because they avoid traumatic application methods, provide a stress-distributed fixation, and provide good cosmesis and outcomes. This article presents the history of the development of surgical bioadhesives, and is also a review of current applications of commercial surgical bioadhesives within neurosurgical procedures and the unmet clinical needs that should be addressed in bioadhesives technologies.

METHODS

A PubMed literature search was performed using the terms "(glue OR bioadhesive OR fibrin OR tisseel OR evicel OR tachosil OR cyanoacrylate OR duraseal OR bioglue) AND (neurosurgery OR spine OR spinal OR dural OR microvascular decompression OR transsphenoidal OR endovascular)." Of 2433 records screened, 168 studies were identified that described the use of bioadhesives in neurosurgical procedures.

RESULTS

The greatest number of studies describing the use of bioadhesives in neurosurgery were identified for endovascular embolization, followed by dural closure and transsphenoidal surgeries. Other common areas of application were for microvascular decompression, skin closure, peripheral nerve repair, and other novel uses. Numerous case reports were also identified describing complications associated with bioadhesive use.

CONCLUSIONS

Despite the paucity of approved indications, surgical bioadhesive use in neurosurgical procedures is prevalent. However, current bioadhesives still each have their own limitations and research is intense in the development of novel solutions.

Endoscopic Endonasal Reconstruction of High-Flow Cerebrospinal Fluid Leak with Fascia Lata "Button" Graft and Nasoseptal Flap: Surgical Technique and Case Series

Background  The endoscopic endonasal approach (EEA) has become increasingly used for resection of skull base tumors in the sellar and suprasellar regions. A nasoseptal flap (NSF) is routinely used for anterior skull base reconstruction; however, there are numerous additional allografts and autografts being used in conjunction with the NSF. The role of perioperative cerebrospinal fluid (CSF) diversion is also unclear. Objective  This study was aimed to analyze success of high-flow CSF leak repair during EEA procedures without use of CSF diversion through lumbar drainage. Methods  A retrospective chart review of patients who had intraoperative high-flow CSF leak during EEA procedures at our institution between January 2013 and December 2017 was performed. CSF leaks were repaired with use of a fascia lata button graft and nasoseptal flap, without use of perioperative lumbar drains. Results  A total of 38 patients were identified (10 male, 28 female). Patient BMIs ranged from 19.7 to 49 kg/m ² (median = 31 kg/m ² ), with 18 patients meeting criteria for obesity (BMI > 30 kg/m ² ) and 12 patients overweight (25 kg/m ²  < BMI < 29.9 kg/m ² ). There was no incidence of postoperative CSF leak. Conclusion  In our experience, the nasoseptal flap used in conjunction with the fascia lata button graft is a safe, effective and robust combination for cranial base reconstruction with high-flow intraoperative CSF leaks, without need for lumbar drains.

Anatomical Risk Factors for Intraoperative Cerebrospinal Fluid Leaks During Transsphenoidal Surgery for Pituitary Adenomas

BACKGROUND

Cerebrospinal fluid (CSF) fistulas are among the most clinically important and frequent complications of transsphenoidal surgery for pituitary adenomas. Between the adenoma and the CSF, a "barrier" exists that consists of ≤3 elements. These, from cephalad to caudad, are the arachnoid, dura mater (sellar diaphragm), and pituitary glandular tissue. The objective of the present study was to determine whether the presence or absence of any of these 3 anatomical elements would be associated with the development of an intraoperative CSF fistula.

METHODS

From November 2016 to June 2018, 40 patients with pituitary adenomas underwent surgery, by transsphenoidal endonasal access, under a microscope. All procedures were filmed in 3 dimensions. The intraoperative findings and preoperative magnetic resonance images were analyzed and compared. The patients who had developed a fistula were compared against those who had not.

RESULTS

In 20 patients, glandular tissue was identified between the tumor and subarachnoid space. In 13, dura mater was evident, and in 7, only the arachnoid was noted. An intraoperative CSF fistula occurred in 6 patients, all of whom had the arachnoid as the only barrier. The presence of a fistula was significantly more likely statistically for patients with an arachnoid-only barrier than for those with any other barrier composition (P < 0.001).

CONCLUSIONS

The anatomical architecture forming the roof of the pituitary fossa is an important determinant of intraoperative CSF fistula risk. When the barrier consists of only the arachnoid, the risk will be significantly greater than when the barrier contains additional elements. Preoperative magnetic resonance imaging would be useful to determine the type of the existing barrier.