A New Porcine Skull Base Model: Fibrin Glue Improves Strength of Cerebrospinal Fluid leak Repairs

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, 134:3425-3436, 2024.

Endoscopic Transnasal Management of Meningoceles and Encephaloceles in Children: A Systematic Review

OBJECTIVE

To review surgical techniques used in the endoscopic transnasal repair of pediatric basal meningoencephaloceles and compare perioperative outcomes in children <2 and ≥2 years old.

DATA SOURCES

MEDLINE, EMBASE, and CENTRAL.

REVIEW METHODS

Data sources were searched from inception to August 22, 2022, using search terms relevant to endoscopic transnasal meningoencephalocele repair in children. Reviews and Meta-analyses were excluded. Primary outcomes were the incidence of intraoperative and postoperative complications, including cerebrospinal fluid leak, recurrence, and reintervention. Quality assessments were performed using Newcastle-Ottawa Scale, ROBIN-I, and NIH.

RESULTS

Overall, 217 patients across 61 studies were identified. The median age at surgery was 4 years (0-18 years). Fifty percent were female; 31% were <2 years. Most defects were meningoencephaloceles (56%), located transethmoidal (80%), and of congenital origin (83%). Seventy-five percent of repairs were multilayered. Children ≥2 years underwent multilayer repairs more frequently than those <2 years (P = 0.004). Children <2 years more frequently experienced postoperative cerebrospinal fluid leaks (P = 0.02), meningoencephalocele recurrence (P < 0.0001), and surgical reintervention (P = 0.005). Following multilayer repair, children <2 years were more likely to experience recurrence (P = 0.0001) and reintervention (P = 0.006).

CONCLUSION

Younger children with basal meningoencephaloceles appear to be at greater risk of postoperative complications following endoscopic endonasal repair, although the quality of available evidence is weakened by incomplete reporting. In the absence of preoperative cerebrospinal fluid leak or meningitis, it may be preferable to delay surgery as access is more conducive to successful repair in older children.

Cerebrospinal fluid rhinorrhoea: does fibrin glue change the surgical outcome?

OBJECTIVE

Cerebrospinal fluid rhinorrhoea takes place when there is a breakdown of the barriers separating the nasal cavity from the subarachnoid space. The aim of this study was to assess the surgical outcomes of endoscopic transnasal cerebrospinal fluid leak repair with and without fibrin glue.

METHOD

There were 43 patients with cerebrospinal fluid rhinorrhoea who underwent surgery for cerebrospinal fluid leak repair between 2014 and 2018. Patients were divided into group A, where fibrin glue was used, and group B, where fibrin glue was not used.

RESULTS

It was found that 74.4 per cent of cases were due to spontaneous cerebrospinal fluid leak. The most common site of a leak was the cribriform plate (65 per cent). There was a success rate of 96.1 per cent (25 of 26) in group A and 83 per cent (15 of 17) in group B. There was no statistically significant difference between the results of the two groups (chi-square test: p = 0.31).

CONCLUSION

There was no statistically significant difference in the results of cerebrospinal fluid leak repair with and without fibrin glue.

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.

Peak Sinus Pressures During Sneezing in Healthy Controls and Post-Skull Base Surgery Patients

OBJECTIVES/HYPOTHESIS

Patients are frequently advised to sneeze with an open mouth and avoid nose-blowing following an endoscopic endonasal approache (EEA) to the skull base, despite a lack of quantitative evidence. This study applies computational fluid dynamics (CFD) to quantify sinus pressures along the skull base during sneezing.

STUDY DESIGN

Case-control series.

METHODS

Computed tomography or magnetic resonance imaging scans of four post-EEA patients and four healthy controls were collected and analyzed utilizing CFD techniques. A pressure drop of 6,000 Pa was applied to the nasopharynx based on values in the literature to simulate expiratory nasal airflow during sneezing. Peak pressures along the skull base in frontal, ethmoid, and sphenoid sinuses were collected.

RESULTS

Significant increases in skull base peak pressure was observed during sneezing, with significant individual variations from 2,185 to 5,685 Pa. Interestingly, healthy controls had significantly higher pressures compared to post-EEA patients (5179.37 ± 198.42 Pa vs. patients 3,347.82 ± 1,472.20 Pa, P < .05), which could be related to higher anterior nasal resistance in unoperated healthy controls (0.44 ± 0.22 vs. 0.31 ± 0.16 Pa/mL/sec for patients, P = .38). The sinus pressure buildup may be due to airway resistance functioning as a valve preventing air from being released quickly. Supporting this theory, there was a strong correlation (r = 0.82) between peak skull base pressure and the ratio of anterior resistance to total resistance. Within-subject variation in pressures between different skull base regions was much lower (average = ~5%).

CONCLUSIONS

This study provided the first quantitative analysis of air pressure along the skull base during sneezing in post-EEA patients through CFD, suggesting that pressure buildup may depend on individual anatomy.

LEVEL OF EVIDENCE

3b Laryngoscope, 130:2138-2143, 2020.

Augmentation of Dural Defect Repairs Strength With an Acrylic Plate in a Porcine Ex Vivo Model

Background

Large skull base defects can be challenging to repair. This study uses a controlled ex vivo model to examine the failure pressures of various dural repairs of large skull base defects using mucosa with fibrin glue under 3 conditions: No Additional Support of the repair, support with a Foley catheter (Direct Support), and with Foley catheter contact over a rigid acrylic plate (Diffuse Support).

Methods

Failure pressures of dural repairs with and without support were determined in a porcine model using an ex vivo closed testing apparatus. In addition, 20 mm × 15 mm dural defects were created. Skull base repairs were performed using porcine dura as an underlay graft followed by a septal mucosa overlay. Saline was infused at 30 mL/h, applying even force to the underside of the graft until repair failure occurred for each condition (none, direct, and diffuse support). Five trials were performed per repair type for a total of 15 repairs.

Results

The mean failure pressures were as follows: No Additional Support, 6.494 ± 2.553 mm Hg; Direct Support, 5.103 ± 3.913 mm Hg; and Diffuse Support, 15.649 ± 2.638 mm Hg. A post hoc Bonferroni-Holm test demonstrated significant difference between No Additional Support and Diffuse Support ( P = .001), as well as Direct Support and Diffuse Support ( P = .002).

Conclusion

Support of dural repairs in this model withstood higher pressures when the Foley catheter’s support is distributed evenly using a flat acrylic plate. Use of this plate is the only repair tested in this model that tolerated normal adult supine intracranial pressures.

Prospective transfrontal sheep model of skull-base reconstruction using vascularized mucosa

BACKGROUND

No high-fidelity animal model exists to examine prospective wound healing following vascularized reconstruction of the skull base. Such a model would require the ability to study the prospective behavior of vascularized mucosal repairs of large dural and arachnoid defects within the intranasal environment. The objective of this study was to therefore develop and validate a novel, in vivo, transfrontal sheep model of cranial base repair using vascularized sinonasal mucosa.

METHODS

Twelve transfrontal craniotomy and 1.5-cm durotomy reconstructions were performed in 60-kg to 70-kg Dorset/Ovis Aries sheep using vascularized mucosa with or without an adjunctive Biodesign™ underlay graft (n = 6 per group). Histologic outcomes were graded (scale, 0 to 4) by a blinded veterinary histopathologist after 7, 14, and 28 days for a range of wound healing parameters.

RESULTS

All sheep tolerated the surgery, which required 148 ± 33 minutes. By day 7, the mucosa was fully adherent with complete partitioning of the sinus and intracranial compartments. Fibroblast infiltration and flap neovascularization scores significantly increased between day 7 (0.3 ± 0.5 and 0.0 ± 0.0) and day 28 (4.0 ± 0.0, p = 0.01 and 2.0 ± 0.8, p = 0.01; respectively), while hemorrhage scores significantly decreased from 2.5 ± 0.6 to 0.0 ± 0.0 (p = 0.01). The inflammatory scores were not significantly different between the heterologous graft and control sides.

CONCLUSION

The described sheep model accurately reflects prospective intranasal wound healing following vascularized mucosal reconstruction of dural defects. This model can be used in future studies to examine novel reconstructive materials, tissue glues, and transmucosal drug delivery to the central nervous system.

Management of cerebrospinal fluid rhinorrhea: an evidence-based review with recommendations

BACKGROUND

Management strategies employed for cases of cerebrospinal fluid (CSF) rhinorrhea vary widely because of limited evidence-based guidance.

METHODS

A systematic review of the literature was performed using PubMed, EMBASE, and Cochrane databases from January 1990 through September 2014 to examine 5 endoscopic repair techniques and 8 perioperative management strategies for CSF rhinorrhea. Benefit-harm assessments, value judgments, and recommendations were made based on the available evidence. Study exclusion criteria were language other than English, pre-1990 studies, case reports, and nonrhinologic leak. All authors agreed on recommendations through an iterative process.

RESULTS

We reviewed 67 studies examining 13 practices pertinent to the management of CSF rhinorrhea, reaching a highest aggregate grade of evidence of B. The literature does not support the routine use of prophylactic antibiotics or lumbar drainage. Various endoscopic repair materials show similar success rates; however, larger defects may benefit from vascularized grafts. There were no relevant studies to address postoperative activity restrictions.

CONCLUSION

Despite relatively low levels of evidence, recommendations for the management of CSF rhinorrhea can be made based on the current literature. Higher-level studies are needed to better determine optimal clinical management approaches.

The efficacy of a lysine-based dendritic hydrogel does not differ from those of commercially available tissue sealants and adhesives: an ex vivo study

Background

Hemostatic agents, tissue adhesives and sealants may contribute to a reduction in hemorrhage-associated morbidity and mortality. Towards this end, we have recently developed a lysine-based dendritic hydrogel (PEG-LysNH₂) that can potentially be used in the management of severe trauma and/or intraoperative bleeding. As a first step in demonstrating the potential utility of this approach, our objective was to ascertain the ability of the PEG-LysNH₂ to adhere to and seal injured tissues, as well as to maintain the seal under physiological conditions.

Methods

The efficacy of the PEG-LysNH₂ in sealing injured tissues was evaluated using an ex-vivo pressure testing system. A 2.5 mm incision was made on intact ex-vivo tissues and then sealed with the PEG-LysNH₂. Application of the PEG-LysNH₂ was followed by 1) step-wise pressure increase to a maximum of 250 mmHg and 2) fluctuating pressures, between 100–180 mmHg with a rate of 3 Hz, over a 24-hour period. The performance of the PEG-LysNH₂ was compared to those of commercially available sealants and adhesives.

Results

During gradual pressure increase, mean pressures at 30 seconds (P₃₀) ranged between 206.36 - 220.17 mmHg for the sealants, and they were greater than control and suture groups (p < 0.01 and p = 0.013, respectively). Additionally, all products held under fluctuating pressures: mean pressures ranged between 135.20 - 160.09 mmHg, and there were no differences observed between groups (p = 0.96).

Conclusions

The efficacy of the PEG-LysNH₂ was significantly superior to conventional injury repair methods (sutures) and did not differ from those of commercially available products when sealing small incisions.

Experimental study on the viscosity and adhesive performance of exogenous liquid fibrin glue

Exogenous fibrin glue (FG) is highly suitable for neurosurgical procedures, because of its viscosity and adhesive properties. Several FGs are commercially available, but only few reports detail their differences. In the present study, we investigated the viscosity and adhesive performance of two types of FG: one is derived from blood donated in Europe and the United States (CSL Behring's Beriplast(®), BP) and the other is derived from blood donated in Japan (the Chemo-Sero-Therapeutic Research Institute's Bolheal(®), BH). The viscosity test that measured fibrinogen viscosity revealed that BP had significantly higher viscosity than BH. Similarly, the dripping test showed that BP traveled a significantly shorter drip distance in the vertical direction than BH, although the transverse diameter of the coagulated FG did not differ statistically significantly. In the tensile strength test, BP showed superior adhesion performance over BH. The histological study of the hematoxylin-eosin-stained specimens in both groups showed favorable adhesion. Although further studies are required on its manufacturing and usage methods, FG shows differences in viscosity and adhesive performance according to the blood from which it is derived. We conclude that it is desirable to select the type and usage method of FG according to the characteristics of the surgical operation in question. Our findings suggest that FG produced from the blood donated in Europe and the United States might be more suitable for use in surgical procedures that demand an especially high degree of viscosity and rapid adhesive performance.

Determining the best graft-sealant combination for skull base repair using a soft tissue in vitro porcine model

BACKGROUND

The purpose of this work was to compare the absolute breaking strength of various soft tissue skull base (SB) repairs in an in vitro porcine model.

METHODS

A burst pressure (BP) testing system was designed using an axial loading force to create increasing hydraulic pressure. Defects measuring 0.5 × 0.5 cm were created in fascia lata samples. Defects were repaired using various grafts (pericranium and 2 different dural substitutes, Alloderm(®) and Durasis(®)) measuring 1.0 × 1.0 cm to cover the deficient area. Grafts were further reinforced onto the fascia background with either fibrin glue (Tisseel(®)) or hydrogel sealant (DuraSeal™). Each combination of graft and sealant was conducted 6 times and tested 24 hours after the repair.

RESULTS

The mean BP (±standard deviation [SD]) were as follows: DuraSeal™-Alloderm, 12.5 ± 5.8 mmHg; DuraSeal™-Durasis, 21.8 ± 20.7 mmHg; DuraSeal™-pericranium, 44.7 ± 30.1 mmHg; Tisseel-Alloderm, 30.6 ± 26.3 mmHg; Tisseel-Durasis, 15.8 ± 18.6 mmHg; and Tisseel-pericranium, 95.5 ± 86 mmHg. One-way analysis of variance showed that the strongest type of repair was Tisseel-pericranium when adjusting for the others (p < 0.0001). The difference in mean BP of repair with DuraSeal™ vs Tisseel(®) was not statistically significant (p = 0.22). Comparing sealants, the use of Alloderm(®) or Durasis(®) decreased the strength of the repair in comparison to pericranium (p < 0.0001). Bonferroni analysis showed a significant difference between pericranium and Alloderm(®) (p < 0.05) and between pericranium and Durasis(®) (p < 0.05) but not between Alloderm(®) and Durasis(®) (p > 0.05).

CONCLUSION

In this model, the strongest type of repair (pressure 6 times higher than normal intracranial pressure) was the combination of Tisseel(®)-pericranium. Our data will help guide surgeons who repair SB defects to choose the best graft and sealant.

Evaluation of Fibrin Sealants for Central Nervous System Sealing in the Mongrel Dog Durotomy Model

BACKGROUND:

Watertight repair of the dura is imperative after neurosurgical procedures involving the brain or spinal cord because inadequately treated leakage of cerebrospinal fluid (CSF) from punctured dura can have serious consequences such as meningitis, arachnoiditis, or epidural abscess.

OBJECTIVE:

To assess the efficacy of Evicel Fibrin Sealant (Human) to prevent CSF leakage using a 2.0-cm durotomy mongrel dog repair model and to compare the tissue response with Tisseel (a fibrin sealant) and Duraseal (a synthetic polyethylene glycol [PEG] hydrogel sealant).

METHODS:

The canine durotomy repair model was used. This well-characterized model assesses the ability of sealants to achieve intraoperative watertight seals of the dura mater, as well as long-term safety and efficacy. This study included 27 mongrel dogs and had a 28-day duration.

RESULTS:

The 3 sealants were 100% effective in preventing CSF leakage intraoperatively at 15 mm Hg. The 2 fibrin sealants were 100% effective in postoperative sealing; the PEG hydrogel was not. Microscopically, the tissue changes induced by Evicel at the durotomy site were similar in nature except for foamy macrophages seen only with the PEG hydrogel. The extent and severity of adhesions at 28 days were less with the fibrin sealants than with the PEG hydrogel.

CONCLUSION:

Evicel, a fibrin sealant, was safe and effective in achieving and maintaining a watertight seal of the dura. The performance of the fibrin sealants was similar to that of the synthetic PEG hydrogel sealant with the exception of a Duraseal seal, which leaked.

Prevention and management of skull base injury

Skull base defects and injuries are rare, but may occur during endoscopic sinus surgery, as a result of facial trauma, or as a result of tumors in the anterior cranial fossa. Injury to the skull base can lead to catastrophic outcomes such as meningitis, brain abscess, neurological deficits, brain hemorrhage, and death. The content presents ways in which a surgeon may work to prevent or minimize injury to the skull base and describes management of skull base injuries when they do occur, reviews the current literature, and describes various reconstruction techniques used in free tissue grafts and pedicled grafts.