Anterior Skull Base Defects Research Articles

Anterior Skull Base Reconstruction Using a Vascularized Pericranial Flap: A Promising Alternative in Sinonasal Malignancies

Abstract Background As the scope of endoscopic techniques continues to evolve in the treatment of advanced sinonasal malignancies, the primary challenge is the reconstruction of the resulting anterior skull base dural defect. Objective This study aimed to assess the efficacy of vascularized pericranial flap reconstruction in addressing anterior skull base defects in sinonasal malignancies, particularly when alternative reconstructive methods, such as nasoseptal flaps, are not viable. Methods We conducted a retrospective review of nine patients who underwent endoscopic resection of sinonasal malignancy followed by vascularized pericranial flap. Our analysis aimed to evaluate the surgical methods utilized, identify any complications that occurred, and assess the postoperative results of the patients. Results Excluding the singular instance of tension pneumocephalus that emerged during the immediate postoperative period, necessitating surgical intervention, our clinical experience was devoid of any complications, with a median follow-up duration of 18 months. It is worth noting that no cases of cerebrospinal fluid leaks or meningitis were reported. Moreover, the follow-up check endoscopy verified the successful integration of the flap and its efficacious coverage of the resection site. Conclusion This study underscores the benefits of using vascularized pericranial flaps as an alternative solution for anterior skull base reconstruction in sinonasal malignancies. The availability of the pericranial flap in the local region, along with its robust blood supply, and the positive outcomes observed in this preliminary series collectively indicate its potential as an integral component of multi-layered reconstruction techniques for addressing anterior skull base defects.

Endoscopic Integrated Multipoint Laser System to Perform Quantitative Measurements for Anterior Skull Base Defects.

Measurements in endoscopic sinus surgery (ESS) are usually obtained with variable accuracy. We aimed to validate endoscopic multipoint integrated laser systems (EIMLS) for use in ESS, which can acquire measurements within one-hundredth of a millimetre. A 4.4 mm flexible endoscopic EIMLS projecting 49 laser points into the view was used to assess simulated anterior skullbase defects. Antero-posterior and lateral measurements were obtained and repeated 20 times by two surgeons. These were compared to measurements with surgical callipers. Intra and inter-observer reliability was assessed. Eighty measurements were obtained of simulated skullbase defects by each otolaryngology surgeon and compared to manual measurements. The mean difference shown was 0.56 cm. Bland-Altman plot shows low bias (0.044) but wide 95% limits of agreement (-1.8-1.9). EIMLS allows reliable and easy to obtain measurements within a simulated ESS environment. Translation of this technology offers promise in a future clinical setting but will require further refinement to improve accuracy.

Utilization of Polydioxanone Plate for Endoscopic Anterior Skull Base Repair: Operative Technique and Long-Term Cohort Outcomes

Abstract Objective The purpose of this study is to report the technical procedure and our experience using a polydioxanone suture (PDS) plate with dural substitute as part of a fully resorbable gasket seal technique to repair anterior skull base defects. Methods A series of patients undergoing anterior skull base reconstruction utilizing our resorbable gasket seal technique from January 2014 to July 2022 was reviewed. Results A total of 155 patients were included. Nine (5.8%) of the included patients developed postoperative cerebrospinal fluid (CSF) leaks requiring reoperation. There were no cases of intraoperative cranial nerve injury or internal carotid artery injury. A total of 103 (66.5%) patients were observed to have an intraoperative CSF leak, including 57 low-flow leaks and 46 high-flow leaks; 1 of 57 (1.8%) patients with low-flow leaks and 8 of 46 (17.4%) patients with high-flow leaks developed a postoperative CSF leak. During the first 3 years that this technique was utilized at our center for the management of high-flow intraoperative CSF leaks, postoperative CSF leaks were documented in 4 of 12 (33.3%) patients, in comparison to 4 of 34 (11.8%) in the following years. Conclusion PDS plate reconstruction confers several advantages and can be used in a diverse set of operative scenarios in conjunction with other reconstruction options. There appeared to be an associated learning curve as surgeons at our center gained experience with this new technique. Our findings show that the PDS plate reconstruction is safe and effective in repairing the skull base.

Endoscopic endonasal anterior skull base surgery : Presentation of a monocentric entity profile

Extended endoscopic endonasal surgery (EEES) is an essential part of treatment of various pathologies of the anterior skull base. In addition to significant improvements in the quality of life of affected patients and alower complication profile compared to open skull base surgery, the therapeutic results are comparable if the indications are correct. Data of all endoscopic endonasal skull base procedures performed at the University Skull Base Center Hamburg under the direction of the Department of Otorhinolaryngology between June 2018 and November 2022 were retrospectively collected. Atotal of 50cases were identified. Of these, 56% (28/50) were malignant tumors, 24% (12/50) were benign pathologies with direct skull base involvement, and 20% (10/50) were anterior skull base defects with rhinoliquorrhea. In 96% (48/50) of cases, the preoperatively set goal of surgery (representative biopsy, complete resection, closure of the skull base defect) could be achieved. Complications gradeIII or higher according to Clavien-Dindo occurred in 4/50cases. During the observation period, n = 5 olfactory neuroblastomas were diagnosed, all of which were exclusively and successfully operated on endoscopically. In recent years, the spectrum of endoscopically resectable pathologies of the anterior skull base has steadily expanded. In particular, midline-related tumors such as olfactory neuroblastoma or iatrogenic/idiopathic skull base defects with cerebrospinal fluid rhinorrhea are treated completely endoscopically with very good results. Nevertheless, there are also limitations to this technique. Due to high variance in the scope of frontobasal surgery, the extent, and the complex anatomy, as well as the overlapping responsibilities of the specialist disciplines, establishment of certified skull base centers and bundling of frontobasal surgery at these centers is highly relevant for quality assurance.

Marginal Tension Release Method of Nasoseptal Flap During Reconstruction of Skull Base Defect

The successful reconstruction of anterior skull base defects following transcribriform or transsphenoidal surgery is pivotal in mitigating the communication between the external environment and the cranial cavity. This intervention is crucial to prevent potential complications, including cerebrospinal fluid leakage and meningitis. The ideal reconstructive flap should possess sufficient vascularity and be of ample size to adequately cover vital nerves and vessels. Predominantly, the nasoseptal flap is employed for the repair of skull base defects. This flap is vascularized by the posterior division of the sphenopalatine artery, ensuring sufficient coverage of the defects. A significant advantage of the nasoseptal flap is its rotational capability, allowing for mobilization and repositioning to effectively cover the defect. Nonetheless, the rotational tension on the nasoseptal flap running from the nasal cavity to the skull base may affect the distal margin of the flap. Alleviation of this tension can be achieved through the insertion of multiple minuscule incisions in the vertical axis of the flap’s border. This report introduces and elaborates on this technique.

Reconstruction of the Anterior Skull Base Using the Nasoseptal Flap: A Review.

The nasoseptal flap is a workhorse reconstructive option for anterior skull base defects during endonasal surgery. This paper highlights the versatility of the nasoseptal flap. After providing a brief historical perspective, this review will focus on the relevant primary literature published in the last ten years. We will touch upon new applications of the flap, how the flap has been modified to expand its reach and robustness, and some of the current limitations. We will conclude by discussing what the future holds for improving upon the design and use of the nasoseptal flap in anterior skull base reconstruction.

Pediatric Anterior Skull Base Reconstruction With Bilateral Temporoparietal Fascial Flap

Emphasis in ASB reconstruction is placed on achieving a watertight dural closure, providing structure for cranial and orbital contents, obliterating dead space, and separation between cranial and sinonasal contents in order to maintain a functional sinonasal system. Pediatric ASB reconstruction also requires consideration for future craniofacial skeletal growth, donor-site morbidity, and psychosocial impact when selecting a reconstructive donor site. Large defects (>3 cm) have traditionally been repaired with free flaps. We describe the successful use of bilateral temporoparietal fascia flaps for a large anterior skull base defect in a pediatric patient after tumor resection. Utilizing bilateral, stacked temporoparietal fascia flaps, which are regionally close to the ASB, avoids morbidity from both extraneous incisions and free flap transfer. The authors show that temporoparietal fascia flaps provide enough tissue bulk and vascularity for safe and effective use in pediatric ASB reconstruction.

Use of Rescue Flaps in the Reconstruction of Anterior Skull Base Defects

Use of Rescue Flaps in the Reconstruction of Anterior Skull Base Defects

Reconstruction of a skull base defect with cutaneous nasocranial communication using a combination of an anterolateral thigh free flap and galeal flap division: a case report

Soft tissue defects can occur in the head and neck due to various causes, and head and neck surgery is often performed to reconstruct soft tissue defects. However, head and neck reconstruction remains delicate and complex as a surgical procedure. The reconstruction of a large defect at the base of the skull, especially after resection of cancer in the anterior base of the skull that has invaded adjacent tissues, is particularly difficult. We present a case of successful reconstruction of a large skull base defect using an anterolateral thigh (ALT) free flap and galeal flap division after tumor resection in the anterior skull base. Paranasal sinus cancer involving the bilateral frontoethmoidal sinuses was resected, and an anterior skull base defect was noted, with communication between the intracranium and nasal cavity and a skin defect at the glabella. A galeal flap was divided to create an anatomical and functional barrier to communication between the nasal cavity and intracranium. The soft tissue defect at the anterior skull base was then reconstructed using an ALT free flap containing the vastus lateralis muscle, and the skin defect at the glabella was covered. No postoperative complications, such as cerebrospinal fluid leakage, developed. The reconstructed flap remained intact after subsequent radiation therapy. Based on this study, we propose that using a galeal flap and ALT free flap in a large skull base defect can yield a robust flap that can endure postoperative radiotherapy with a minimal risk of complications.

Reliability of High-resolution Gadolinium-enhanced MR Cisternography and Gasket-seal Technique for Management of Anterior Skull Base Defects

PurposePrecise preoperative localization of anterior skull base defects is important to plan surgical access, increase the success rate and reduce complications. A stable closure of the defect is vital to prevent recurrence of cerebrospinal fluid (CSF) rhinorrhea. The purpose of this retrospective case series was to evaluate the reliability of a new high-resolution gadolinium-enhanced compressed-sensing SPACE technique (CS T1 SPACE) for magnetic resonance (MR) cisternography to detect cerebrospinal fluid leaks of the anterior skull base and to assess the long-term success rate of the gasket-seal technique for closure of skull base defects.MethodAll patients with spontaneous or postoperative cerebrospinal fluid rhinorrhea and defects of the anterior skull base presenting to the Departments of Otorhinolaryngology and Neurosurgery between 2019 and 2020, receiving a computed tomography (CT) cisternography and MR cisternography (on a 3T whole-body MR scanner using a 64-channel head and neck coil) with CS T1 SPACE sequence and closure of the defect with the gasket-seal technique, were enrolled in the study. For the cisternography, iodinated contrast agent (15 ml Solutrast 250 M®), saline (4 mL) mixed with a 0.5 mL of gadoteridol was injected into the lumbar subarachnoid space.ResultsA total of four patients were included in the study and MR cisternography with CS T1 SPACE sequence was able to precisely localize CSF leaks in all patients. The imaging results correlated with intraoperative findings. All defects could be successfully closed with the gasket-seal technique. The mean follow-up was 35.25 months (range 33–37 months).ConclusionMR cisternography with CS T1 SPACE sequence could be a promising technique for precise localization of CSF leaks and the gasket-seal technique resulted in good closure of the CSF fistula in this case series.

Multilayer Anterior Skull Base Reconstruction with Cortical Rib Bone Graft: Preliminary Experience

During the past decades, different methods have been described for anterior skull base reconstruction. Regarding larger skull base defects, few investigators have described the use of bone grafts to foster support and prevent frontal lobe sagging, herniation, or falling. The aim of this study is to describe the use of a rib bone graft, which could be an option in these cases due to its rigidity and dimensions. We retrospectively collected preoperative, intraoperative, and postoperative data at the last follow-up of 10 patients who underwent multilayer anterior skull base reconstruction, including rib bone graft, for large anterior cranial base defects at 2 tertiary care academic hospitals. Eight patients underwent endoscopic craniectomy for sinonasal malignancies, and the other two underwent transnasal endoscopic surgery for congenital meningoencephalocele. Anterior skull base defects measured on average 3.8 cm ± 0.9 SD antero-posteriorly (range 2.5-5 cm) and 2.3 ± 0.9 SD latero-laterally (range 0.9-4 cm). Multilayer reconstruction was performed in all cases, including a rib bone graft positioned as intracranial extradural layer. No patient experienced thoracic complications during the postoperative period. No side effects related to the bone graft or meningoencephalocele occurrence were reported after a mean follow-up of 8.0 ± 6.3 months. The use of a cortical rib bone graft could be a safe and effective option in skull base reconstruction when managing large defects after cancer removal.

Pericranial Flap-Based Multilayer Reconstruction of Endoscopic Transcribriform Craniectomy for Sinonasal Malignancies.

Diffusion of endoscopic techniques for the resection of ethmoid bone malignancies through a transcribriform approach (TA) has raised new challenges regarding reconstruction options to reduce post-operative complications. Although there is consensus on the advantages of vascularized flaps over free grafts for large defects, no standard protocol exists on reconstruction procedures. In addition, although the pedicled nasoseptal flap has been extensively discussed, few studies have been published on extranasal pedicled flaps. The aim of this manuscript is to provide a detailed description of a reconstruction technique for large anterior skull base defects with the pericranial flap as part of a multilayered reconstruction. Moreover, patients treated with this approach were retrospectively assessed for post-operative complications. A detailed description of the reconstruction procedure as performed in our departments is provided. Pictures depicting the main surgical steps are also included. In addition, preliminary functional results from a retrospective series of patients who underwent a TA and subsequent pericranial flap-based multilayer reconstruction for ethmoid roof malignancies between 2016 and 2022 at two institutional centers are reported. 16 patients were included in the study. Nine patients (56.3%) underwent adjuvant radiotherapy. Two patients had a biochemically-confirmed postoperative CSF leak. Only one of the two patients required surgical revision. During follow-up (mean 13 months), no other early nor delayed complications were observed. A standardized surgical technique with pericranial flap as part of a multilayered reconstruction for large anterior skull base defects following resection of sinonasal malignancies is proposed, which appears to be a safe choice when endonasal flaps are not available. Level 4 Laryngoscope, 133:2942-2947, 2023.

Transorbital transposition of the temporoparietal fascia flap to reconstruct the skull base defects: A preclinical study with comparison to the transpterygoid transposition.

Transpterygoid transposition of the temporoparietal fascia flap (TPFF) is a feasible selection for ventral skull base defect (VSBD) reconstruction, but not anterior skull base defect (ASBD) reconstruction, after expanded endoscopic endonasal approach (EEEA). The goal of this study is to introduce the transorbital transposition of the TPFF for skull base defects reconstruction after EEEA, and make quantitative comparison between the transpterygoid transposition and transorbital transposition. Cadaveric dissections were performed in five adult cadaveric heads with creating three transporting corridors bilaterally, encompassing superior transorbital corridor, inferior transorbital corridor, and transpterygoid corridor. For each transporting corridor, the minimum necessary length of the TPFF for skull base defects reconstruction was measured. The areas of ASBD and VSBD were 1019.63 ± 176.32 mm2 and 572.99 ± 126.21 mm2 . The length of the harvested TPFF was 149.38 ± 6.21 mm. In contrast to the transpterygoid transposition with incomplete coverage, transorbital transposition of the TPFF allowed full coverage of ASBD with a minimum necessary length of 109.75 ± 8.31 mm. For VSBD reconstruction, transorbital transposition of the TPFF needs shorter minimum necessary length (123.88 ± 4.49 mm) than transpterygoid transposition (138.00 ± 6.28 mm). Transorbital corridor is a novel pathway for transporting the TPFF into the sinonasal cavity for skull base defects reconstruction after EEEA. In comparison with transpterygoid transposition, transorbital transposition provides wider coverage of skull base defects with a fixed length of the TPFF.

Our Experience in Trans Nasal Endoscopic Repair of Anterior Skull Base Defects Reinforced with Multiple Layers of Graft Materials.

Aims: To determine the best technique to repair anterior skull base defects using various grafts. Materials & Methods: This Ambi-directional cohort study was carried out at a tertiary care hospital from May 2019 to October 2021. A total of 17 patients who underwent Endoscopic Repair of Anterior Skull Base Defects using various grafts were included in the study. Detailed history and clinical evaluation followed by Diagnostic Nasal Endoscopy, Biochemical and Radiological investigations were done for all patients with postoperative follow-up for at least 6 months. Results: Most common site of anterior skull base defect in our study group was the posterior wall of the sphenoid sinus. Various graft materials used in our study were fascia lata, thigh fat, Hadad flap, Septal cartilage, nasal septal bone chip, septal mucosal free flap, surgicel and fibrin glue. The most commonly used sequence of graft materials used is the fat(underlay) - fascia lata - fat(overlay). Various complications that occurred were nasal bleeding, residual CSF leak, localized collection of pus in the Septal region, cerebral oedema and Alar trauma. Conclusions: The success of Anterior skull base defect repair depends on watertight Dural closure with multiple layers of grafts to prevent postoperative CSF leak. Although dependent on the Surgeon's preference, usually the sequence of an underlay fat - fascia lata - overlay fat followed by glue/gel foam/Hadad flap works well. Even after discharging the patient, regular follow-up and evaluation ensure that the graft is in situ and there is no CSF leak or other complication.

How I do it: epidural transposition of the temporoparietal fascia flap for anterior skull base reconstruction.

Multilayer closures and the use of vascularized flaps have been showed to be very effective in the reconstruction of the anterior skull base (ASB) after extended endonasal approaches resulting in large bone and dural defects. In the case of unavailability of a local flap, regional ones like the temporoparietal fascia flap (TPFF), used until now via a transpterygoïd route (Bolzoni Villaret et al. in Eur Arch Otorhinolaryngol 270(4):1473-1479, 2023; Fortes et al. in Laryngoscope 117(6):970-976, 2017; Veyrat et al. in Acta Neurochir (Wien) 158(12):2291-2294, 2016), can be an effective alternative. We describe a step-by-step technique of TPFF transposition via an epidural supraorbital corridor for the reconstruction of a large midline ASB defect. TPFF is a promising alternative for the reconstruction of the ASB defects.

Combined Endoscopic Endonasal and Transpalatal Repair of Congenital Anterior Cranial Fossa Agenesis.

Congenital basal meningoceles and encephaloceles are rare pathologies that may present in isolation or with characteristic-associated clinical features. Rarely, children with congenital midline defects may present with massive encephaloceles secondary to anterior cranial fossa agenesis. Traditionally, transcranial approaches with frontal craniotomies were used to reduce the herniated contents and repair the skull base defect. However, high rates of morbidity and mortality associated with craniotomies have favored the development and adoption of less-invasive techniques. To present a novel technique for combined endoscopic endonasal and transpalatal repair of a giant basal meningocele through an extensive sphenoethmoidal skull base defect. A representative case of congenital anterior cranial fossa agenesis with a giant meningocele was selected. Clinical and radiological presentations were reviewed, and the intraoperative surgical technique was documented and recorded. A surgical video highlighting each surgical step was included to complement the description of the technique. The surgical outcome from the selected case is also presented. This report describes a combined endoscopic endonasal and transpalatal approach to repair an extensive anterior skull base defect with herniation of intracranial content. This technique capitalizes on the advantages of each approach to address this complex pathology.

Differences in the predicted nasoseptal flap length among races: A propensity score matching analysis.

We compared the lengths of a nasoseptal flap (NSF) and skull base according to race, age, and sex. We performed paranasal sinus computed tomography in 19,961 adult patients between 2003 and 2022. The race of the patients was East Asian (n = 71), Caucasian (n = 71), or Middle Eastern (n = 71). The expected lengths of the NSF and anterior skull base defect were measured and analyzed according to race, age, and sex. Compared with Caucasians and Middle Easterners, East Asians had a shorter NSF length (p < 0.001) and lower ratio of the expected NSF length to the expected defect length (p < 0.001). There was no difference in the values among age groups. The expected NSF length was longer, and the ratio of the expected NSF length to the expected defect length was higher, in males than females (p < 0.001 for both). East Asians and females had a shorter NSF length and lower ratio of expected NSF to surgical defect lengths after anterior skull base reconstruction compared with the other races and with males, respectively. Anatomical differences should be considered when long NSF lengths are required, such as for anterior skull base reconstruction.

Possible Role of the New Identified “Subarachnoid Lymphatic-Like Membrane” in Traumatic Brain Injury

The radial forearm free flap (RFFF) is an indispensable tool for the reconstruction of a range of defects, including those of the skull base. Several options for routing of the RFFF pedicle have been described, and the parapharyngeal corridor (PC) has been proposed as an option and employed for a nasopharyngeal defect. However, there are no reports of its use for the reconstruction of anterior skull base defects. The objective of this study is to describe the technique for free tissue reconstruction of anterior skull base defects using the RFFF and routing of the pedicle via the PC.Relevant neurovascular landmarks and critical surgical steps for reconstruction of anterior skull base defects with an RFFF and routing of the pedicle via the PC are reported using an illustrative clinical case and cadaveric dissections.We present a case of a 70-year-old man who underwent endoscopic transcribriform resection of cT4N0 sinonasal squamous cell carcinoma and was left with a large anterior skull base defect that persisted despite several repair attempts. An RFFF was utilized to repair the defect. This report is the first description of the clinical use of the PC for free tissue repair of an anterior skull base defect.The PC is an option for routing the pedicle during the reconstruction of anterior skull base defects. When the corridor is prepared as described in this case, a direct route exists from the anterior skull base to cervical vessels, simultaneously maximizing the reach of the pedicle and minimizing the risk of kinking.

Radial Forearm Free Flap with Parapharyngeal Pedicle Corridor for Reconstruction of Anterior Skull Base Defects

The radial forearm free flap (RFFF) is an indispensable tool for the reconstruction of a range of defects, including those of the skull base. Several options for routing of the RFFF pedicle have been described, and the parapharyngeal corridor (PC) has been proposed as an option and employed for a nasopharyngeal defect. However, there are no reports of its use for the reconstruction of anterior skull base defects. The objective of this study is to describe the technique for free tissue reconstruction of anterior skull base defects using the RFFF and routing of the pedicle via the PC. Relevant neurovascular landmarks and critical surgical steps for reconstruction of anterior skull base defects with an RFFF and routing of the pedicle via the PC are reported using an illustrative clinical case and cadaveric dissections. We present a case of a 70-year-old man who underwent endoscopic transcribriform resection of cT4N0 sinonasal squamous cell carcinoma and was left with a large anterior skull base defect that persisted despite several repair attempts. An RFFF was utilized to repair the defect. This report is the first description of the clinical use of the PC for free tissue repair of an anterior skull base defect. The PC is an option for routing the pedicle during the reconstruction of anterior skull base defects. When the corridor is prepared as described in this case, a direct route exists from the anterior skull base to cervical vessels, simultaneously maximizing the reach of the pedicle and minimizing the risk of kinking.

Predictive model for preoperative risk calculation of cerebrospinal fluid leak after resection of midline craniofacial mass lesions

BackgroundComplex anterior skull base defects produced by resection of mass lesions vary in size and configuration and may be extensive. We analyzed the largest single-center series of midline craniofacial lesions extending intra- and extracranially. The study aims at the development of a predictive model for preoperative measurement of the risk of the postoperative cerebrospinal fluid (CSF) leak based on patients' characteristics and surgical plans. Methods166 male and 149 female patients with mean age 40,5 years (1 year and – 81 years) operated for benign and tumor-like midline craniofacial mass lesions were retrospectively analyzed using logistic regression method (Ridge regression algorithm was selected). The overall CSF leak rate was 9.6%. The ROSE algorithm and ‘glmnet’ software suite in R were used to overcome the cohort's disbalance and avoid overtraining the model. ResultsThe most influential modifiable negative predictor of the postoperative CSF leak was the use of extracranial and combined approaches. Use of transbasal approaches, gross total resection, utilization of one or two vascularized flaps for skull base reconstruction were the foremost modifiable predictors of a good outcome. Criterium of elevated risk was established at 50% with a specificity of the model as high as 0.83. ConclusionsThe performed study has allowed for identifying the most significant predictors of postoperative CSF leak and developing an effective formula to estimate the risk of this complication using data known for each patient. We believe that the suggested web-based online calculator can be helpful for decision making support in off-pattern clinical situations.