Comparison of dural closure alternatives: an experimental study

Alaska Pollock-derived Gelatin Sealant has Higher Sealing Strength than, and Comparable Biocompatibility with, Fibrin Sealant in Porcine and Rat Dural Injury Models

STUDY DESIGN

Burst strength study in porcine dural models and functional and histological study in rat dural models.

OBJECTIVE

This study aimed to investigate the sealing strength and biocompatibility of Alaska pollock-derived gelatin (ApGltn) and fibrin sealants in disrupted dural injuries.

SUMMARY OF BACKGROUND DATA

Disruption of the dura mater occurs during spine surgery, leading to cerebrospinal fluid leakage. Fibrin sealant is usually applied to ruptured sites; however, it lacks sealing strength. A novel biocompatible sealant composed of ApGltn was recently demonstrated to have good burst strength and biocompatibility in the porcine aorta.

METHODS

Ten porcine dura maters with central holes were covered with ApGltn and fibrin sealants (five samples per group). The maximum burst strength of each sealant was measured, and histological examination was performed after burst testing. Twenty-seven dura maters of male Wistar rats were used for functional and histopathological evaluations. The rats were treated with three surgical interventions: defect + ApGltn sealant; defect + fibrin sealant; defect alone (nine rats per group). Macroscopic confirmation of the sealant, hindlimb motor function analysis, and histopathological examination were performed at two, four, and eight weeks after the procedure.

RESULTS

The maximum burst strength of the ApGltn sealant was ~4.4 times higher than that of the fibrin sealant (68.1±12.1 vs . 15.6±8.7 mmHg; P <0.001). Histological examination confirmed that the ApGltn sealant showed tight adhesion to the dural surface, whereas a gap was observed between the fibrin sealant and the dura mater. In the rat model, the ApGltn sealant resulted in spinal function and dural histological findings similar to those of the fibrin sealant.

CONCLUSION

The ApGltn sealant had a higher sealing strength than, and comparable effect on dura regeneration with, the fibrin sealant.

Comparison of supratentorial meningioma resection outcomes by dural reconstruction technique

OBJECTIVE

Excision of intracranial meningiomas often requires resection or coagulation of the dura mater. The choice of dural closure technique is individualized and based on surgeon preference. The objective of this study was to determine outcomes following various dural closure techniques for supratentorial meningiomas.

METHODS

A retrospective, single-center cohort study was performed for patients who underwent excision of supratentorial meningiomas from 2000 to 2019. Outcomes including operative time, postoperative in-hospital complications, readmission, causes of readmission including surgical site infection, pseudomeningocele, need for shunt surgery, and imaging appearance of pseudomeningocele on long-term follow-up imaging were compared. Univariate and multivariable analyses were conducted.

RESULTS

A total of 353 patients who had complete clinical and operative data available for review were included. Of these patients, 227 (64.3%) had nonsutured dural graft reconstruction and 126 (35.7%) had sutured dural repair, including primary closure, artificial dura, or pericranial graft. There was significant variability in using nonsutured dural reconstruction compared with sutured dural repair technique among surgeons (p < 0.001). Tumors with sagittal sinus involvement were more likely to undergo nonsutured closure (n = 79, 34.8%) than dural repair (n = 26, 20.6%) (p = 0.003). There were no other differences in preoperative imaging findings or WHO grade. Frequency of surgical site infection and pseudomeningocele, need for shunt surgery, and recurrence were similar between those undergoing nonsutured and those undergoing sutured dural repair. The mean operative time for the study cohort was 234.9 (SD 106.6) minutes. The nonsutured dural reconstruction group had a significantly shorter mean operative time (223.9 [SD 99.7] minutes) than the sutured dural repair group (254.5 [SD 115.8] minutes) (p = 0.015). In a multivariable linear regression analysis, after controlling for tumor size and sinus involvement, nonsutured dural graft reconstruction was associated with a 36.8-minute reduction (95% CI -60.3 to -13.2 minutes; p = 0.002) in operative time.

CONCLUSIONS

Dural reconstruction using a nonsutured graft and sutured dural repair exhibit similar postoperative outcomes for patients undergoing resection for supratentorial meningiomas. Although sutured grafts may sometimes be necessary, nonsutured graft reconstruction for most supratentorial meningioma resections may suffice. The decreased operative time associated with nonsutured grafts may ultimately result in cost savings. These findings should be taken into consideration when selecting a dural reconstruction technique for supratentorial meningioma.

Primary Dural Repair via an Endoscopic Endonasal Corridor: Preliminary Development of a 3D-Printed Model for Training

Objectives Endonasal suturing is an investigational method for dural repair that has been reported to decrease the incidence of cerebrospinal fluid fistula. This method requires handling of single-shaft instrumentation in the narrow endonasal corridor. In this study, we designed a low-cost, surgical model using three-dimensional (3D) printing technology to simulate dural repair through the endonasal corridor and subsequently assess the utility of the model for surgical training.

Methods Using an Ultimaker 2+ printer, a 3D-printed replica of the cranial base and nasal cavity was fitted with tissue allograft to recapitulate the dural layer. Residents, fellows, and attending surgeons were asked to place two sutures using a 0-degree endoscope and single-shaft needle driver. Task completion time was recorded. Participants were asked to fill out a Likert scale questionnaire after the experiment.

Results Twenty-six participants were separated into groups based on their prior endoscope experience: novice, intermediate, and expert. Twenty-one (95.5%) residents and fellows rated the model as “excellent” or “good” in enhancing their technical skills with endoscopic instrumentation. Three of four (75%) of attendings felt that the model was “excellent” or “good” in usefulness for training in dural suturing. Novice participants required an average of 11 minutes for task completion, as compared with 8.7 minutes for intermediates and 5.7 minutes for experts.

Conclusion The proposed model appears to be highly effective in enhancing the endoscopic skills and recapitulating the task of dural repair. Such a low-cost model may be especially important in enhancing endoscopic facility in countries/regions with limited access to cadaveric specimens.

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.

A new type of bilayer dural substitute candidate made up of modified chitin and bacterial cellulose

In the field of neurosurgery, timely and effective repair of dura mater plays an important role in stabilizing the physiological functions of the human body. Therefore, the aim of this study is to develop a new type of bilayer membrane as a dural substitute candidate. It consists of a dense layer that prevents cerebrospinal fluid leakage and a porous layer that promotes tissue regeneration. The dense layer, a composite polysaccharid film, was composed of high molecular weight chitosan (CS) and bacterial cellulose (BC). The porous layer, a composite polysaccharid scaffold cross-linked by glutaraldehyde (GA) or citric acid (CA) respectively, was composed of O-carboxymethyl chitin (O-CMCH) and BC. The bilayer dural substitutes were characterized in terms of SEM, mechanical behavior, swelling rate, anti-leakage test, in vitro cytotoxicity, proliferation, and animal experiment. Results indicated that all prepared dural substitutes were tightly bound between layers without excessively large cavities. The porous layer showed appropriate pore size (90～200 μm) with high porous connectivity. The optimized bilayer dural substitutes showed suitable swelling rate and mechanical behavior. Furthermore, no leakage was observed during testing, no cytotoxicity effect on NIH/3T3 cells, and exhibited excellent cell proliferation promoting properties. Also, it was observed that it did not deform in the peritoneal environment of mice, and tissue inflammation was mild.

Applications of materials for dural reconstruction in pre-clinical and clinical studies: Advantages and drawbacks, efficacy, and selections

The dura mater provides a barrier to protect the tissue underneath and cerebrospinal fluid. However, dural defects normally cause cerebrospinal fluid leakage and other complications, such as wound infections, meningitis, etc. Therefore, the reconstruction of dura mater has important clinical significance. Current dural reconstruction materials include: homologous, acellular, natural, synthetic, and composite materials. This review comprehensively summarizes the characteristics and efficacy of these dural substitutes, especially in clinical applications, including the advantages and drawbacks of those from different sources, the host tissue response in pre-clinical studies and clinical practice, and the comparison of these materials across different surgical procedures. Furthermore, the selections of materials for different surgical procedures are highlighted. Finally, the challenges and future perspectives in the development of ideal dural repair materials are discussed.