The use of polydioxanone plates for endoscopic skull base repair

Endoscopic Reconstruction of the Anterior Skull Base Following Tumor Resection: Application of a Novel Bioabsorbable Plate

OBJECTIVE

Endoscopic repair of skull base defects is required following resection of intracranial pathology via the endoscopic endonasal approach (EEA). Many closure techniques have been described, but choosing between techniques remains controversial. We report outcomes of 560 EEA procedures of skull base reconstruction performed on 508 patients over a 15-year-period. Halfway through this period, we adopted the use of a rigid, bioabsorbable extrasellar plate for reconstruction, enabling a comparison between this technique and those used previously.

METHODS

All patients undergoing EEA from 2005 to 2019 at our institution were retrospectively reviewed. Demographic information, surgical pathology, tumor dimensions and radiographic features, reconstructive technique, and patient-related outcomes were collected and analyzed with univariate and multivariate statistical modeling.

RESULTS

Five-hundred sixty procedures were performed on 508 patients. The series complication rate was 8.2%. Overall, cerebrospinal fluid (CSF) leak rate was 5.0% but varied significantly across closure techniques (p < 0.001). Critically, the CSF leak rate in the 272 cases prior to our 2013 adoption of the Resorb-X Plate (RXP) was 8.5%, whereas leak rate in the subsequent 288 cases was 1.7%. RXP was protective against CSF leak (p = 0.001), whereas gross total resection (GTR) correlated with increased leak rate (p = 0.001). Patient BMI was significantly associated with risk of leak (p = 0.047). Other variables did not impact leak risk.

CONCLUSION

Reconstructive technique, extent of resection, and patient BMI significantly contributed to CSF leak rate. GTR was associated with increased leak risk while the RXP was protective. The bioabsorbable RXP is an effective option for rigid skull base repair with comparatively few complications.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:1092-1098, 2023.

Interdisciplinary management of skull base surgery

Skull base surgery remains one of the challenging areas in the field of cranio-maxillofacial surgery, otolaryngology and neurosurgery. Subsequent reconstruction of bone and soft tissue are an essential component to restore function and appearance after ablative surgery. Establishment of interdisciplinary tumor boards with presentation of the individual patient cases have become standard. Multiplanar reconstruction using MRI or CT imaging techniques combined with virtual 3D planning allow precise planning of the procedures. Intraoperative navigation helps for complete resection of malignant findings with safety margins; surgical approaches provide a good overview of the surgical site. Reconstruction using local flaps have a low complication rate with equally reliable results in reconstruction of small tissue defects. Free flap surgery makes reconstruction of large tissue defects possible. Alloplastic materials are alternatively used for reconstruction of bone defects. Based on selected patients, treatment algorithms and standard surgical procedures in extracerebral skull base surgery will be illustrated. Current techniques and new approaches will be discussed with emphasize on hard and soft tissue reconstruction.

Deployment of a bioabsorbable plate as the rigid buttress for skull base repair after endoscopic pituitary surgery

Background

Bioresorbable alloplastic implants have become desirable as a rigid buttress for reconstructing skull base defects. This study aimed to describe the use of a biodegradable plate (PolyMax RAPID) in skull base repair of endoscopic endonasal pituitary surgery and to investigate the clinical outcome and safety of this novel method.

Methods

Between January 2019 and January 2020, 22 patients with pituitary adenomas who underwent endoscopic skull base repair with a Polymax RAPID plate were included. After endonasal transsphenoidal surgery, a trimmed bioresorbable plate was placed in the position between the dura and the bone of the skull base to reconstruct the sellar floor and buttress the pituitary gland and sellar packing. The patient demographics, radiologic imaging, and postoperative outcomes were carefully reviewed. All patients were followed up by a routine nasal endoscopic assessment and radiologic examinations.

Results

The present study comprised 10 (45.5%) males and 12 (54.4%) females with an average age of 51.9 years. There were 7 (31.8%) growth hormone (GH) secreting adenomas, 2 (9.1%) thyroid stimulating hormone (TSH) secreting adenomas, and 13 (59.1%) non-functioning adenomas. Enlarged sellar floor and paranasal sinusitis were seen in 13 (59.1%) and 11 (50.0%) cases shown by preoperative computed tomography (CT) or magnetic resonance imaging (MRI), respectively. There were 6 (27.3%) grade-1 and 16 (72.7%) grade-0 cases by intraoperative cerebrospinal fluid (CSF) leak grading. None of these patients received lumbar drains postoperatively and no postoperative CSF rhinorrhea was detected in our series. The PolyMax RAPID plates which could be clearly identified on postoperative CT or sagittal T1-weighted MRI were shown to provide an ideal rigid buttress for sellar repair.

Conclusions

The Polymax RAPID plate can be an optimal implant to achieve rigid repair of sellar floor defects after endonasal transsphenoidal pituitary surgery.

Vascular pedicled flaps for skull base defect reconstruction

OBJECTIVE

Techniques for reconstruction of skull base defects have advanced greatly since the introduction of the vascular pedicled nasoseptal flap in 2006. The objective of this review is to assess the current state of the field by examining both intranasal and extranasal techniques of vascular pedicled skull base defect repair, their indications and success rates, and novel techniques that are currently under investigation.

METHODS

A review of the literature describing the use of vascular pedicled flaps in skull base defect reconstruction was conducted using PubMed and Google Scholar.

RESULTS

The nasoseptal flap remains the most widely used vascular pedicled flap for endoscopic repair of skull base defects. Its ease of harvest, wide arch of rotation, and high success rates make it a popular choice among surgeons. Several variations including a "rescue" nasopseptal flap have been developed. Other less commonly used pedicled intranasal flaps include the middle turbinate flap and the posterior pedicled inferior turbinate flap. Additionally, several novel vascular pedicled flaps have been developed and tested in small cohorts of patients. Extranasal flaps such as the pericranial flap and the temporoparietal fascia flap are used less frequently than intranasal flaps. However, they remain valuable options for reconstruction in certain situations.

CONCLUSION

Advancements continue to be made in the field of skull base defect reconstruction using vascular pedicled flaps. Though the nasoseptal flap remains the most widely utilized option, additional intranasal techniques continue to be developed and tested to optimize surgical outcomes and patient care.

LEVEL OF EVIDENCE

NA.

Bilaminar Chitosan Scaffold for Sellar Floor Repair in Transsphenoidal Surgery

Background

Endoscopic endonasal transsphenoidal surgery (EETS) is a standard technique used to approach sellar tumors. It is relatively safe, minimally invasive and carries a low risk of complications. However, one of the common complications reported with this technique is CSF leakage which causes morbidity, an increase in recovery time and hospital costs. This complication usually occurs from violation of the diaphragma sellae and a defect in the structures of the sellar floor or incomplete repair. In this article we report the first case with the use of a novel bilaminar chitosan scaffold which can be potentially used in the repair of the sellar floor, primarily aiming to the bony part of this structure.

Case Presentation

After a personalized design employing a tissue engineering strategy, we reconstructed the sellar floor in a 65-year-old woman who had undergone EETS for a pituitary adenoma with progressive bilateral visual loss. To repair the bony defect of the sellar floor, we used a novel bilaminar chitosan scaffold. The patient had an unremarkable postoperative course with no evidence of CSF leak. The polymer was well tolerated without toxicity, infection or complications. After 2 years of follow up the patient remains neurologically intact, and in good endocrinological status.

Conclusion

This is the first report of the use of this biomaterial and its biocompatibility in a clinical setting for the repair of the sellar floor during EETS. Our experience with chitosan bilaminar scaffold and in several preclinical studies in the literature have demonstrated good biocompatibility and effective bioengineered bone regeneration due to its excellent osteoconductive properties, this study pretends to be one landmark for further clinical research and larger case series with the use of this personalized tissue engineering materials in order to see they real efficacy to increase the surgeon armamentarium.

A Novel Technique for Endoscopic Repair of Large Anterior Skull Base Defects: The PDS Wrap

Background

Endoscopic skull base surgery continues to push boundaries with increased complexity of work and subsequently larger defects requiring repair. Robust repair following endoscopic skull base surgery is essential to reduce significant postoperative complications such as cerebrospinal fluid leak, meningitis, and pneumocephalus.

Objective

To describe and further validate our novel technique of using a polydioxanone plate wrap used in large anterior skull base resections where brain herniation can be of concern.

Method

After large resections where there is obvious brain herniation, our PDS (polydioxanone) wrap can be deployed to provide rigid support to the brain. The PDS plate is wrapped in a dural graft material and sutured closed in order to allow deployment by releasing the sutures when in position under the bony ridge of the defect.

Conclusion

Till date we have successfully used this technique in 3 patients following large skull base resections of olfactory meningiomas, where there was herniation of the brain. Postoperatively, there was no evidence of cerebrospinal fluid leak. We therefore recommend the use of the PDS wrap to prevent brain herniation and provide additional support to the repair.

Treating nasoethmoidal encephalocele in a low-resource country: a surgical experience from a Philippine multidisciplinary craniofacial team

PURPOSE

It was described that nasoethmoidal encephalocele repair in the Philippines has been limited by insufficient resources, financial constraints, and a lack of surgical expertise. The purpose of this study was to report initial results and complications of Philippine patients with nasoethmoidal encephalocele surgically managed with an approach adapted to an environment with limited financial resources.

METHODS

All patients (n = 21) with nasoethmoidal encephalocele who underwent intracranial and extracranial repairs (frontal wedge osteotomy to access the encephalocele cyst and cranial base defect, dural defect repair, split frontal grafts fixed with polydioxanone sutures to reconstruct the cranial defect and nasal dorsum, and medial canthopexy) from January 2015 to May 2017 were included. The correlations between sizes of masses and cranial defects with the occurrence of complications were tested. The surgical results were classified based on a previously published outcome grading scales I-IV on the need for additional surgery.

RESULTS

Nineteen patients (90.5%) had unremarkable post-operative course. Two patients (9.5%) presented with complications (cerebrospinal fluid leak and surgical site infection) which were successfully managed with no additional surgery. The sizes of masses and cranial defects were not correlated (p > 0.05) with complications. The overall rate of surgical results ranked according to the need for additional surgery was 2.4 ± 0.5 (between categories II and III).

CONCLUSIONS

We reported successful surgical repair of nasoethmoidal encephaloceles in Philippine patients by a local multidisciplinary craniofacial team.

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.

Pediatric Meningoencephaloceles Endoscopic Endonasal Repair: Our Experience

Background

Pediatric patients presenting with a nasal mass is uncommon and a high index of suspicion for it to be a meningoencephalocele is essential. Majority of these are congenital and require early intervention owing to the risk of meningitis. Surgery in these cases is very challenging because of the risk of anesthesia and limited space.

Objective

This study aimed to describe our technique and experience in managing pediatric meningoencephaloceles.

Methods

A retrospective study of 19 pediatric patients (age ranging from 40-day-old infants to 11.5-year-old children) was conducted at our tertiary care center from January 2012 to February 2017. Patients presenting with an intranasal meningoencephalocele were treated by endoscopic approach, using otological microinstruments. After detailed imaging and clinical evaluation, a tailored repair, using fat/fascia/cartilage, a multilayer closure, was carried out in all cases.

Results

All patients had a successful repair and recovery, except for one death following an episode of convulsion. There was a minor circumferential narrowing of the nasal vestibule and synechia formation in 2 of our cases.

Conclusion

Transnasal endoscopic repair of meningoencephalocele is minimally invasive. It avoids permanent anosmia and is cosmetic. A combination of miniaturized instruments and a 4-mm 0° nasal endoscope gives excellent visual field and an adequate working space. Owing to the larger defects in congenital meningoencephaloceles, a multilayer repair provides excellent outcomes.