Stepwise Algorithm for Skull Base Reconstruction in Endoscopic Endonasal Surgery: From the Simple to the Complex

ABSTRACTBACKGROUND: Endoscopic transnasal surgery has gained rapid global acceptance over the last two decades. The growing literature and understanding of anterior skull base endoscopic anatomy, in addition to new dedicated endoscopic instruments and tools, have helped to expand the use of the transnasal route in skull base surgery.OBJECTIVE: Report our early experience in expanded endoscopic transnasal surgery (EETS) and approach to skull base neoplasms.DESIGN: Descriptive, retrospective case series.SETTING: Major tertiary care center.PATIENTS AND METHODS: A retrospective case review was conducted at King Saud University Medical City between December 2014 and August 2019. Cases with skull base neoplasms that underwent EETS were included. EETS was defined as endoscopic surgical exposure that extended beyond the sellar margins (prechiasmatic sulcus superiorly, clival recess inferiorly, cavernous carotid lines laterally). Routine transsphenoidal pituitary neoplasms, neoplasms of sinonasal origin and meningoencephaloceles were excluded.MAIN OUTCOME MEASURES: Preoperative clinical assessment, imaging results, surgical approach, and hospital course were all retrieved from the patient electronic charts. Clinical follow-up, perioperative complications, and gross residual tumor rates were documented and reviewed.SAMPLE SIZE AND CHARACTERISTICS: 45 cases of EETS, 13 males and 32 females with mean age of 39.0 (17.7) years (range 2–70 years).RESULTS: The series comprised a wide range of pathologies, including giant pituitary adenoma (8 cases), meningioma (23 cases), craniopharyngioma (4 cases), chordoma (4 cases), optic pathway glioma (2 cases), epidermoid neoplasms (2 cases), astrocytoma (1 case), and teratoma (1 case). For the entire series, gross total resection was achieved in 25/45 operations (55.5%). Postoperative cerebrospinal fluid leak was the most common complication observed in 9 patients (20%) which were all managed endoscopically. Major vascular complications occurred in 2 patients (4.4%) and are described. Other complications are outlined as well. No mortality was observed.CONCLUSIONS: EETS to the skull base can be done with results comparable to traditional approaches. More work is needed to expand our experience, improve outcomes, and educate the public and medical community in our region about the usefulness of this approach.LIMITATIONS: Sample size and study design.CONFLICT OF INTEREST: None.

Single-Layer Fascia Patchwork Closure for the Extended Endoscopic Transsphenoidal Transtuberculum Transplanum Approach: Deep Suturing Technique and Preliminary Results

The nasoseptal flap (NSF) has been a versatile reconstructive option for extended endonasal skull base surgery, significantly decreasing postoperative cerebrospinal fluid (CSF) leakage rates. One failure mechanism of concern is NSF necrosis. It has been postulated that immediate postoperative MRI flap enhancement can predict flap necrosis. This retrospective study analyzes NSF enhancement to assess for flap viability and CSF leakage. Patients from 2012 to 2020 who underwent extended endoscopic endonasal surgery with NSF reconstruction were assessed. Immediate postoperative MRI and delayed 3-month MRI were compared for NSF enhancement. Enhancement was graded as no enhancement, partial, or complete enhancement. Patient demographics, tumor type, intraoperative CSF leak grade, and postoperative CSF leakage were assessed based on flap enhancement patterns. Of 713 patients who underwent endoscopic endonasal surgery, 64 required NSF reconstruction. On the immediate postoperative MRI, 45 patients (70%) had complete flap enhancement, 9 (14%) had partial, and 10 (16%) no enhancement. On the 3-month MRI, 59 patients (92%) had complete flap enhancement and 5 (8%) had partial enhancement. There was significant improvement of flap enhancement between immediate postoperative and 3-month MRI (P = .002). All patients with no initial enhancement had complete enhancement at 3 months. Of those with partial enhancement, 2 remained partial and 7 had complete enhancement at 3 months. Overall, 44 patients (69%) had no change between MRI scans, 17 (27%) improved, and 3 (5%) had decreased enhancement. There was no correlation between intraoperative CSF leak rates and flap enhancement. Four patients had postoperative CSF leaks, 2 having complete immediate enhancement, 1 partial, and 1 without enhancement (P = .85). Overall, immediate postoperative MRI NSF enhancement (or lack thereof) did not predict enhancement at the 3-month MRI and did not correlate with postoperative CSF leakage. Hence, one should not rely solely on postoperative flap enhancement to assess the viability of the dural reconstruction.

ObjectiveComplete sellar floor reconstruction is critical to avoid postoperative cerebrospinal fluid (CSF) leakage during transsphenoidal surgery. Recently, the pedicled nasoseptal flap has undergone many modifications and eventually proved to be valuable and efficient. However, using these nasoseptal flaps in all patients who undergo transsphenoidal surgery, including those who had none or only minor CSF leakage, appears to be overly invasive and time-consuming.MethodsPatients undergoing endoscopic endonasal transsphenoidal tumor surgery within a 5 year-period were reviewed. Since 2009, we classified the intraoperative CSF leakage into grades from 0 to 3. Sellar floor reconstruction was tailored to each leak grade. We did not use any tissue grafts such as abdominal fat and did not include any procedures of CSF diversions such as lumbar drainage.ResultsAmong 200 cases in 188 patients (147 pituitary adenoma and 41 other pathologies), intraoperative CSF leakage was observed in 27.4% of 197 cases : 14.7% Grade 1, 4.6% Grade 2a, 3.0% Grade 2b, and 5.1% Grade 3. Postoperative CSF leakage was observed in none of the cases. Septal bone buttress was used for Grade 1 to 3 leakages instead of any other foreign materials. Pedicled nasoseptal flap was used for Grades 2b and 3 leakages. Unused septal bones and nasoseptal flaps were repositioned.ConclusionModified classification of intraoperative CSF leaks and tailored repair technique in a multilayered fashion using an en-bloc harvested septal bone and vascularized nasoseptal flaps is an effective and reliable method for the prevention of postoperative CSF leaks.

Endoscopic endonasal surgery for skull base tumors has advanced significantly, but postoperative cerebrospinal fluid (CSF) leak remains a significant concern. Introducing the vascularized pedicled nasoseptal flap (PNSF) has markedly reduced CSF leak rates, though outcomes remain variable across different studies. This systematic review and meta-analysis aimed to compare the efficacy of vascularized versus nonvascularized reconstruction techniques in these procedures.Three databases (PubMed, Cochrane, and Embase) were systematically searched to identify studies comparing CSF leak rates between PNSF and nonvascularized techniques for reconstruction after endoscopic endonasal skull base surgeries. It was designed according to the preferred reporting items for systematic reviews and meta-analyses reporting guidelines. Statistical analysis was performed using Review Manager, with heterogeneity evaluated via the I 2 statistic.After thorough selection, twenty articles were selected, and a total of 4,088 patients were included, of whom 1,851 were assigned to the nasoseptal flap group, and 2,237 were assigned to the no-flap group. The postoperative CSF leak ratio was significantly lower in the group that underwent reconstruction with PNSF compared with all the other grouped methods, respectively, 3.4 and 5.6% (odds ratio [OR]: 0.48; 95% confidence interval [CI]: 0.34–0.66; p < 0.00001; I 2 = 54%).Our results suggest that using the PNSF is associated with a lower incidence of postoperative CSF leak than other reconstruction techniques in endoscopic skull base surgeries and may be used for patients at risk of this complication.

Post-operative CSF leak is the major source of morbidity following endoscopic transsphenoidal surgery. The purpose of this study was to identify factors associated with post-operative CSF leak in patients undergoing this surgery and facilitate the prospective identification of patients at higher risk of this complication. A review of a prospectively maintained database containing details of 270 endoscopic transsphenoidal operations performed by the senior author over a 9-year period was performed. Univariate analysis was performed using the Chi-squared and Fisher's exact tests, as appropriate. A logistic regression model was constructed for multivariate analysis. The rate of post-operative CSF leak in this series was 9%. On univariate analysis, previous surgery, resection of craniopharyngiomas, adenomas causing Cushing's disease and intra-operative CSF leaks were associated with an increased risk of post-operative CSF leak. The use of a vascularised nasoseptal flap and increasing surgical experience were associated with a decreased rate of CSF leak. On multivariate analysis, a resection of tumour for Cushing's disease (OR 5.79, 95% CI 1.53-21.95, p= 0.01) and an intra-operative CSF leak (OR 4.56, 95% CI 1.56-13.32, p= 0.006) were associated with an increased risk of post-operative CSF leak. Increasing surgical experience (OR 0.14, 95% CI 0.04-0.46, p= 0.001) was strongly associated with a decreased risk of post-operative CSF leak. Increasing surgical experience is a strong predictor of a decreased risk of developing post-operative CSF leak following endoscopic transsphenoidal surgery. Patients with Cushing's disease and those who develop an intra-operative CSF leak should be managed with meticulous skull base repair and close observation for signs of CSF leak post-operatively.

Objectives Postoperative cerebrospinal fluid (CSF) leaks ussually occur after intraoperative dural tears. Sometimes, however, CSF leaks are found postoperatively even in the absence of intraoperative dural tears. The frequency and course of postoperative CSF leaks without intraoperative dural tears after posterior lumbar interbody fusion (PLIF) were investigated. Material and Methods The subjects were 200 patients (112 males, 88 females, age 69 ± 10 years) who underwent PLIF at our hospital from July 2014 to March 2020. The causative diseases were lumbar spinal stenosis in 167 cases, spondylolisthesis in 11 cases, lumbar disc herniation in 16 cases, and degenerative scoliosis in six cases. Of all the 200 cases, 27 were revision cases. If a dural tear occurred during the operation, dural repair was performed intraoperatively. Drain suction with negative pressure was discontinued when postoperative CSF leaks were found. Results Of the 180 patients without intraoperative dural tears, postoperative CSF leaks were observed in 27 patients (15.0%). Of these 27 patients, three symptomatic patients required reoperation. Residual CSF accumulations one year after surgery were observed in 14 patients, of whom six patients had severe CSF accumulations with a dural sac deformity, all of whom were asymptomatic. Of the 20 patients with intraoperative dural tears, 16 patients (80.0%) had postoperative CSF leaks, but none needed reoperation. Conclusion The frequency of postoperative CSF leaks without intraoperative dural tears was 15.0% in the present study. They require strict follow-up because they can cause severe postoperative CSF accumulations and may require reoperation.

PurposeWe evaluated the effectiveness of a less invasive skull base reconstruction technique using a fibrin glue-soaked gelatin sponge (FGGS) and collagen matrix to prevent cerebrospinal fluid (CSF) leakage following endoscopic transsphenoidal surgery (ETSS). This approach minimizes the need for fascia harvesting and the use of nasoseptal flaps.MethodsWe retrospectively analyzed data from 558 ETSS, excluding Rathke’s cleft cysts, performed at our institution. Surgeries were classified by intraoperative CSF leakage grade according to Esposito’s classification. Patients’ characteristics and intraoperative findings were analyzed to assess potential risk factors for postoperative CSF leakage. Postoperative CSF leakage rates were compared between the pre-collagen matrix (428 surgeries) and collagen matrix (130 surgeries) periods.ResultsFGGS-based reconstruction without fat grafts was performed in 73.7% of surgeries, including 99.4% of grade 0 and 88.5% of grade 1 leaks. Nasoseptal flaps were used in only eight surgeries (1.4%), and fascia was not used at all, either for watertight dural suturing or for multilayer reconstruction. The overall postoperative CSF leakage rate was 1.8% (10/558). The leakage rates by intraoperative CSF leak grade were 0%, 1.7%, 5.6%, and 1.1% for grades 0, 1, 2, and 3, respectively. Postoperative CSF leakage was associated with unfamiliar techniques and excessive bucking during extubation. During the collagen matrix period, although 33.8% of surgeries involved grade 3 high-flow CSF leaks, only one surgery (0.8%; 1/130) resulted in postoperative CSF leakage.ConclusionsAs a less invasive technique, skull base reconstruction using FGGS and/or a collagen matrix was effective in reducing postoperative CSF leakage.

This was a retrospective cohort study. The purpose of this study was to examine the association between postoperative cerebrospinal fluid (CSF) leak and anterior cervical discectomy and fusion (ACDF). Specifically, we evaluated: (1) demographic risk factors; (2) comorbid risk factors; (3) indications for surgery; and (4) lengths of stay. CSF leak is a rare but serious complication of ACDF. Currently, there is a paucity of literature describing the risk factors for CSF leak following ACDF. The Nationwide Inpatient Sample was used to identify all patients who underwent cervical fusion using the anterior approach with excision of intervertebral disc between 1998 and 2010. Patients who had a diagnosis of ossification of the posterior longitudinal ligament in the cervical region were excluded. All patients who had a CSF leak were identified. Demographics and comorbidities were compared via χ analysis, and logistic regression to calculate the odds of having a CSF leak. Of the 1,261,140 patients identified, 3048 patients (0.24%) had a postoperative CSF leak. Patients who were between the ages of 55 and 69 years (P=0.038) and 70 years or older (P=0.001) were at an increased risk of CSF leak compared with patients who were aged 40-54 years. Non-white race (P=0.021), obesity, (P<0.001) and hypertension (P=0.025) were associated with an increased risk of CSF leak, but diabetes (P=0.966) and hyperlipidemia (P=0.226) were not. Herniated disc diagnosis was associated with decreased risk of CSF leak (P=0.032), but cervical spondylosis with myelopathy patients had an increased risk (P<0.001). Patients with CSF leak had a mean length of stay of 6.0 days compared with 2.1 days among controls. Surgical candidates who are older and non-white should be counseled of their increased risk for CSF leak in preoperative planning. Patients who are obese and have hypertension may benefit from medical optimization before surgery. Level III.

A prospective study of endoscopic expanded endonasal approaches (EEA) with nasoseptal flap reconstructions revealed anecdotal evidence of less available relative septal length in pediatric patients. Our goal is to use radioanatomic analysis of computed tomography (CT) scans to determine limitations of the nasoseptal flap in pediatric skull base reconstruction and to describe clinical outcomes after using the nasoseptal flap in six pediatric patients. Six pediatric patients who underwent EEA with nasoseptal flap reconstruction were prospectively analyzed for flap coverage and postoperative cerebrospinal fluid (CSF) leak. Fifty maxillofacial CTs of individuals <18 years of age and 10 adult images underwent radioanatomic analysis. Measurements included potential nasoseptal flap dimensions and dimensions required to reconstruct an anterior skull base defect, a trans-sellar defect, and a transclival defect. Measurements were compared to determine if flap size would be sufficient to cover independent EEA defects within different age groups. Two out of three patients <14 years of age had inadequate flap coverage; one had a postoperative CSF leak. Patients >14 years of age had adequate flap coverage. Average potential flap length is less than average anterior skull base length until age 9 years to 10 years, and less than average trans-sellar defect length until age 6 years to 7 years. Septal growth is most rapid between 10 years and 13 years. : The pedicled nasoseptal flap may not be a viable option for EEA reconstruction in children <10 years of age. This flap is a reliable option in patients >14 years of age, as their septums are comparable to adults. Patients 10 years to 13 years of age require careful consideration of facial analysis and preoperative radioanatomic evaluation on an individual basis. Laryngoscope, 2009.

Postoperative spinal cerebrospinal fluid (CSF) leaks are common but rarely cause extensive CSF collections that require specialized imaging to detect the site of the dural breach. To investigate the use of digital subtraction myelography (DSM) for patients with extensive extradural CSF collections after spine surgery. A retrospective review was performed to identify a consecutive group of patients with extensive postoperative spinal CSF leaks who underwent DSM. Twenty-one patients (9 men and 12 women) were identified. The mean age was 46.7 years (range, 17-75 years). The mean duration of the postoperative CSF leak was 3.3 years (range, 3 months to 21 years). MRI showed superficial siderosis in 6 patients. DSM showed the exact location of the CSF leak in 19 (90%) of the 21 patients. These 19 patients all underwent surgery to repair the CSF leak, and the location of the CSF leak could be confirmed intraoperatively in all 19 patients. In 4 (19%) of the 21 patients, DSM also showed a CSF-venous fistula at the same location as the postoperative dural tear. In this study, DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy.

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.

Cerebrospinal fluid (CSF) leak is a crucial complication after endoscopic skull base surgery. Therefore, multilayer reconstruction with grafts is as essential as a reconstruction with pedicled flaps. Although widely used, the multilayer technique with autologous fascia lata has drawbacks, such as additional wound and donor site complications. We compared acellular dermal graft and banked homologous fascia lata graft (alternative grafts) with autologous fascia lata graft for high-flow CSF leak repair. We retrospectively enrolled 193 subjects who underwent endoscopic skull base reconstruction with multilayer fascial grafts and nasoseptal flap for high-flow CSF leaks from November 2014 to February 2020 at a single institution. Acellular dermal matrix (ADM), banked homologous fascia lata, and autologous fascia lata were used in 48 (24.9%), 102 (52.8%), and 43 (22.3%) patients, respectively. Postoperative CSF leaks occurred in 23 (11.9%) patients and meningitis in 8 (4.1%). There was no significant difference in postoperative CSF leak (p = 0.36) and meningitis (p = 0.17) across the graft groups. Additionally, we could not find out contributing risk factors for postoperative CSF leak and meningitis. ADM and banked homologous fascia lata are non-inferior to autologous fascia lata for endoscopic skull base reconstruction in water-tight reconstruction or safety without additional donor site morbidities.

The Role of Comprehensive Structural Preservation Strategy in Skull Base Reconstruction Following Endoscopic Endonasal Surgery for Pituitary Neuroendocrine Tumors: A Retrospective Single-Center Study.

Proper skull base reconstruction after endoscopic endonasal pituitary surgery is of great importance to decrease the rate of complications. To assess the safety and efficacy of reconstruction with materials other than fat graft and naso-septal flaps (NSF) to avoid their associated morbidities. The authors' institutional database for patients who underwent endoscopic endonasal approach for pituitary adenoma was reviewed. Exclusion criteria included recurrence, postradiation therapy, and reconstruction by fat graft or NSF. They were divided into group A, where collagen matrix (CM) (DuraGen® Plus Matrix, Integra LifeSciences Corporation, Plainsboro, New Jersey) alone was used; group B, where CM and simple mucoperiosteum graft were used and group C, which included cases without CM utilization. The study included 252 patients. No age, gender, or body mass index statistically significant difference between groups. Group B included the largest tumor size (23.0 mm) in comparison to groups A (18.0 mm) and C (13.0 mm). Suprasellar extension was more frequently present (49.4%) in comparison to groups A (29.8%, P=.001) and C (21.2%, P<.001). Postoperative cerebrospinal fluid (CSF) leak rate was 0%, 2.9%, and 6% in groups A, B, and C, respectively. In group B, the CSF leak rate decreased from 45.9% intraoperatively to 2.9% postoperatively (P<.001). In group A, the CSF leak reduction rate was almost statistically significant (P=.06). Utilization of CM and simple mucosperiosteal graft in skull base reconstruction following pituitary adenoma surgery is an effective method to avoid the morbidities associated with NSF or fat graft.