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Lumbar Drains Decrease the Risk of Postoperative Cerebrospinal Fluid Leak Following Endonasal Endoscopic Surgery for Suprasellar Meningiomas in Patients With High Body Mass Index
Abstract
BACKGROUND: Postoperative cerebrospinal fluid (CSF) leak is a persistent, albeit much less prominent, complication following endonasal endoscopic surgery. The pathology with highest risk is suprasellar meningiomas. A postoperative lumbar drain (LD) is used to decrease the risk of CSF leak but is not universally accepted.
OBJECTIVE: To compare the rates of postoperative CSF leak between patients with and without LD who underwent endonasal endoscopic surgical resection of suprasellar meningiomas.
METHODS: A consecutive series of newly diagnosed suprasellar meningiomas was drawn from a prospectively acquired database of endonasal endoscopic surgeries at our institution. An intraoperative, preresection LD was placed and left open at 5 cc/h for ∼48 h. In a subset of patients, the LD could not be placed. Rates of postoperative CSF leak were compared between patients with and without an LD.
RESULTS: Twenty-five patients underwent endonasal endoscopic surgical resection of suprasellar meningiomas. An LD could not be placed in 2 patients. There were 2 postoperative CSF leaks (8%), both of which occurred in the patients who did not have an LD (P = .0033). The average body mass index (BMI) of the patients in whom the LD could not be placed was 39.1 kg/m², compared with 27.6 kg/m² for those in whom the LD could be placed (P = .009). In the subgroup of obese patients (BMI > 30 kg/m²), LD placement was protective against postoperative CSF leak (P = .022).
CONCLUSION: The inability to place an LD in patients with obesity is a risk factor for postoperative CSF leak. An LD may be useful to prevent postoperative CSF leak, particularly in patients with elevated BMI.
... Also, while lateral parts of the dome can be rolled and excised, the tumor base extending laterally to the optic nerve, ICA, or lamina papyracea is a contraindication, wherein we prefer the supraorbital keyhole approach. [7][8][9] Further, closure of the skull base defect is an important step to prevent CSF leak. ...
... A major disadvantage is the risk of CSF leak in the postoperative period. [7] However, the leak rate has reduced significantly with the use of vascularized naso septal flaps, multilayer closure, and experience. ...
https://youtu.be/wKAu8oV6_dw?si=MsKXKsLwLJ8N6T_q
... 16 The more serious concern is that skull base reconstruction can fail even when multilayer reconstructions are combined with the NSF and followed by LD. 22 Moreover, LD carries risks such as overdrainage, infection, radiculopathy, and restricted mobilization, 16 and its use after EEEA for craniopharyngiomas remains controversial. 16,[23][24][25][26] Previous studies have covered the impact of other factors (e.g., body mass index [BMI] and repair method) on CSF leak after EEEA, 23,[26][27][28][29][30] but these results are inconsistent and likely due to heterogeneous pathologies or small sample sizes. Until now, there has been a lack of systematic studies focusing on the risk factors for CSF leak after EEEA for craniopharyngiomas. ...
... Perioperative LD is frequently used to lower ICP and prevent postoperative CSF leak. 25,43 However, Cavallo et al. 6 and Caggiano et al. 24 both noted that the use of LD did not have much effect on preventing postoperative CSF leak. Zwagerman et al. 16 reported that postoperative LD could reduce the risk of postoperative CSF leak in the setting of large dural defects located at the anterior and posterior fossa rather than the suprasellar region. ...
OBJECTIVE
Over the last decade, the extended endoscopic endonasal approach (EEEA) has evolved as a credible surgical alternative for removing craniopharyngiomas. However, postoperative cerebrospinal fluid (CSF) leak remains one of the most pressing concerns. Craniopharyngiomas often invade the third ventricle, resulting in a higher rate of third ventricle opening after surgery and potentially increasing the risk of postoperative CSF leak. Identifying the risk factors associated with CSF leak after EEEA for craniopharyngiomas may have more clinical value. Nevertheless, there is a lack of systematic studies on the topic. Previous studies yielded inconsistent results, probably due to heterogeneous pathologies or small sample sizes. Hence, the authors present the largest known single-institution case series of the use of purely EEEA for craniopharyngiomas to systematically study the risk factors for postoperative CSF leak.
METHODS
The authors retrospectively reviewed 364 cases of adult patients with craniopharyngiomas who were treated at their institution from January 2019 to August 2022, and they analyzed the risk factors for postoperative CSF leak.
RESULTS
The overall rate of postoperative CSF leak was 4.7%. In the univariate analysis, larger dural defect size (OR 8.293, 95% CI 3.711–18.534, p < 0.001) and lower preoperative serum albumin level (OR 0.812, 95% CI 0.710–0.928, p = 0.002) were associated with higher rates of postoperative CSF leak. Predominantly cystic tumors (OR 0.325, 95% CI 0.122–0.869, p = 0.025) were linked to decreased risk of postoperative CSF leak. However, postoperative lumbar drainage (OR 2.587, 95% CI 0.580–11.537, p = 0.213) and third ventricle opening (OR 1.718, 95% CI 0.548–5.384, p = 0.353) were not related to postoperative CSF leak. In the multivariate analysis, larger dural defect size (OR 8.545, 95% CI 3.684–19.821, p < 0.001) and lower preoperative serum albumin level (OR 0.787, 95% CI 0.673–0.919, p = 0.002) were identified as independent risk factors for postoperative CSF leak.
CONCLUSIONS
The authors’ repair technique yielded a reliable reconstructive outcome for high-flow CSF leak in EEEA for craniopharyngioma. Lower preoperative serum albumin level and larger dural defect size were identified as independent risk factors for postoperative CSF leak, potentially providing new insights into minimizing the risk of postoperative CSF leak. Third ventricle opening was not associated with postoperative CSF leak. Lumbar drainage may not be necessary for high-flow intraoperative leak, but this finding may require validation with a prospective randomized controlled trial in the future.
... As with EEA, lumbar drain placement may be useful for high-risk leaks to prevent postoperative CSF leaks and pseudomeningoceles. 23,24 This might include patients not only with large dural openings but also with prior radiation, diabetes, and/or high body mass index. Skull base meningiomas are more likely to be WHO Grade I, associated with memory deficits, and at risk for STR and recurrence due to the limited working angles offered by most conventional open craniotomy approaches. ...
BACKGROUND AND OBJECTIVE
The endoscopic lateral transorbital approach (eLTOA) is a relatively new approach to the skull base that has only recently been applied in vivo in the management of complex skull base pathology. Most meningiomas removed with this approach have been in the spheno-orbital location. We present a series of select purely sphenoid wing and middle fossa meningiomas removed through eLTOA. The objective here was to describe the selection criteria and results of eLTOA for a subset of sphenoid wing and middle fossa meningiomas.
METHODS
This is a retrospective study based on a prospectively maintained database of consecutive cases of eLTOA operated on at our institution by the lead author. The cohort's clinical and radiographic characteristics and outcome are presented.
RESULTS
Five patients underwent eLTOA to remove 3 sphenoid wing and 2 middle fossa meningiomas. The mean tumor volume was 11.9 cm ³ . Gross total resection was achieved in all cases. There were no intraoperative complications. Postoperatively, there was one case of subretinal hemorrhage, which was corrected by open vitrectomy repair, and one case of cerebrospinal fluid leak, which resolved with lumbar drainage. Three patients presented with visual impairment, 1 improved, 1 remained stable, and 1 worsened, but returned to stable after vitrectomy repair. All patients have been free of disease at a median follow-up of 8.9 months.
CONCLUSION
eLTOA provides a direct minimal access corridor to certain well-selected sphenoid wing and middle fossa meningiomas. eLTOA minimizes brain retraction and provides a high rate of gross total resection. Meningiomas appropriately selected based on size, type, and location of dural attachment, and the eLTOA is a safe, rapid, and highly effective procedure with acceptable morbidity.
... In our clinical practice, the adoption of prophylactic lumbar drainage in patients was not a customary procedure due to the limited body of evidence supporting its substantial impact on diminishing the incidence of postoperative cerebrospinal fluid (CSF) leakage (8)(9)(10). The surgical procedures were performed by a highly skilled and experienced surgeon (Dr. ...
Objective
The objective of this study is to study the effect of in situ bone flap (ISBF) repositioning, a recently proposed rigid skull base reconstruction technique, on patients diagnosed with pituitary adenoma undergoing endoscopic endonasal approach (EEA).
Method
A retrospective analysis was conducted on 188 patients with pituitary adenomas who underwent EEA from February 2018 to September 2022. Patients were divided into the ISBF group and non-ISBF group, according to whether ISBF was used during skull base reconstruction.
Results
Of the 75 patients in the non-ISBF group, 6 had postoperative cerebrospinal fluid (CSF) leakage (8%), while only 1 of 113 patients in the ISBF group (0.8%) had postoperative CSF leakage, indicating that the incidence of postoperative CSF leakage in the ISBF group was significantly lower than that in the non-ISBF group (P = 0.033). In addition, we also found that the postoperative hospitalization days of patients in the ISBF group (5.34 ± 1.24) were significantly less than those in the non-ISBF group (6.83 ± 1.91, P = 0.015).
Conclusion
ISBF repositioning is a safe, effective, and convenient rigid skull base reconstruction method for patients with pituitary adenoma treated by EEA, which can significantly reduce the rate of postoperative CSF leakage and shorten postoperative hospital stays.
The goal of this American Rhinologic Society expert practice statement (EPS) is to summarize the best available evidence for technical factors that optimize outcomes in skull base reconstruction following endoscopic skull base surgery for intradural pathologies. These topics include the use of free mucosal grafts versus vascularized pedicled nasoseptal flaps; the use of autologous versus synthetic grafts; and the roles of lumbar drains, dural sealants, and nasal packing. This EPS was developed following the recommended methodology and approval process as previously outlined. As there are a myriad of techniques and limited agreement on the accepted principles of skull base reconstruction, this EPS aims to summarize the existing evidence and provide clinically meaningful guidance on these divergent practices. Following a modified Delphi approach, five statements were developed, four of which reached consensus and one of which reached near consensus. These statements and the accompanying evidence are summarized along with an assessment of future needs.
Pituitary neoplasm is the commonest sellar pathology, where pituitary adenoma heads the list, it accounts for 25% of all intracranial neoplasm. Although it is a benign lesion in most cases is located in a complex region; adjacent to important structures: optic chiasm, internal carotid arteries, suprasellar cistern, and cavernous sinuses, it presents with a variety of clinical scenarios. The Sella is situated at the center of the skull base, this made surgical access via craniotomy very challenging and is associated with considerable morbidity. Transnasal endoscopic pituitary surgery (TEPS) evolved rapidly, almost replacing the craniotomy approach, because it is minimally invasive and gives direct sellar access with excellent visualization. On the other hand, the learning curve of TEPS requires meticulous training to acquire surgical skills. Indications of TEPS, technique, complications, their prevention, and management are described. The multidisciplinary approach in managing pituitary adenoma is addressed, where a team of an endocrinologist, neurosurgeon, otolaryngologist, ophthalmologist, anesthesiologist, and neuroradiologist decide on a management plan for patients. Other disciplines share management of certain cases that is Oncologist, ICU specialists, and obstetrician. Long term follow-up is required by endocrinologists whereas revision surgery is considered in some patients.
Objective:
Despite its efficacy and minimal invasiveness, the clean-contaminated nature of endoscopic transnasal surgery (ETS) may be susceptible to central nervous system surgical site infections (CNS-SSIs), especially when involving intradural exposure. However, the profiles of ETS-associated CNS-SSIs are not fully elucidated.
Methods:
The institutional ETS cases performed between May 2017 and March 2023 were retrospectively analysed. The incidences of CNS-SSIs were calculated, and their risk factors were examined.
Results:
The incidence of CNS-SSIs was 2.3% (7/305) in the entire cohort and 5.0% (7/140) in ETSs with intradural exposure. All the CNS-SSIs were meningitis and developed following ETS with intradural exposure. The incidences were 0%, 5.6%, and 5.8% in ETSs with Esposito grade 1, 2, and 3 intraoperative CSF leakage, respectively. Among the pre- and intra-operative factors, body mass index (unit odds ratio [OR], 0.62; 95% confidence interval [CI], 0.44-0.89; P < 0.01), serum albumin (unit OR, 0.03; 95% CI, 0.0007-0.92; P = 0.02), and American Society of Anesthesiologists physical status score (unit OR, 20.7; 95% CI, 1.65-259; P < 0.01) were significantly associated with CNS-SSIs. Moreover, postoperative CSF leakage was also significantly associated with CNS-SSIs (OR, 18.4; 95% CI, 3.55-95.0; P < 0.01).
Conclusions:
The incidence of ETS-associated CNS-SSIs is acceptably low. Intradural exposure was a prerequisite for CNS-SSIs. Malnutrition and poor comorbidity status should be recognized as important risks for CNS-SSIs in ETS.
Introduction Pedicled nasoseptal flap (NSF) placement is a critical component of skull base reconstruction after endoscopic endonasal approaches (EEAs). The effectiveness of NSF reuse has not been thoroughly studied. Prior reports using flaps harvested at one center and reused at another may have technical variability bias.
Methods We identified patients who underwent both their initial and NSF-reused surgeries at Weill Cornell Medical College from 2004 to 2022 using a prospective database of all EEAs. Surgical pathology, intraoperative leak grade, use of cerebrospinal fluid (CSF) diversion and skull base coverage were examined. The primary outcome measure was occurrence of CSF leak.
Results Fourteen patients (six women, eight men) underwent 14 first time and 14 revision operations with median age of 36.6 years (interquartile range [IQR]: 23.9–61.3) at the time of the NSF reuse. The median interval between the first NSF use and reuse was 70.6 months (IQR: 16.6–87). Eight patients were operated on for pituitary adenoma. Nonadenomas included three craniopharyngiomas and one case each of epidermoid, ependymoma, and chordoma. There were 16 high-flow, 8 low-flow intraoperative leaks, and 4 with no leak. CSF diversion was used in 24 operations. There were three postoperative leaks, one after a first operation and two after NSF reuse. All postoperative CSF leaks, whether first or second operations, occurred in cases with both high-flow intraoperative CSF leak and incomplete NSF coverage (p = 0.006).
Conclusions NSF reuse is effective at preventing postoperative CSF leak. The primary predictors of leak are high-flow intraoperative leak and inadequate defect coverage with NSF, regardless of the operation number.
Objective:
Lumbar drains (LD) are commonly used during endoscopic repair of cerebrospinal fluid (CSF) rhinorrhea, either to facilitate graft healing or to monitor CSF fluid dynamics. However, the indications and necessity of LD placement remains controversial. The current study sought to evaluate endoscopic CSF leak repair outcomes in the setting of limited LD use.
Methods:
Patients who underwent endoscopic repair of CSF rhinorrhea between 2004 and 2014 were identified by a review of medical records. Demographic and clinical data were extracted and compared between patients who had surgery with and patients who had surgery without a perioperative LD. A univariate analysis was performed to identify factors predictive of recurrence.
Results:
A total of 107 patients (116 surgical procedures) were identified, with a mean follow-up of 15.8 months. Eighty-eight of 107 patients (82.2%) had surgery without an LD. The mean hospital stay was 4.48 days in the LD group versus 1.03 days in the non-LD group (p < 0.00001). There was no difference in recurrence rate between the LD and non-LD groups. Predictors of recurrence included repair technique (p = 0.04) and size of defect (p = 0.005). Body mass index, leak site (ethmoid, sphenoid, frontal), and etiology (spontaneous, iatrogenic, traumatic) were not predictive of leak recurrence.
Conclusion:
Use of LDs in endoscopic CSF leak repair was not associated with reduced recurrence rates, regardless of leak etiology, and resulted in a significant increase in hospital length of stay. Although the use of perioperative LDs to monitor CSF dynamics may have some therapeutic and diagnostic advantages, it may not be associated with clinically significant improvements in patient outcomes or recurrence rates.
Background:
Historically, lumbar drains (LD) have played a prominent role in endonasal skull base surgery. Over the past few decades, advancements in techniques have augmented our ability to successfully reconstruct complex skull base defects and often obviates the need for cerebrospinal fluid (CSF) diversion. Clarity on the appropriate use of LDs is needed.
Objective:
To examine the literature for the need for LDs in contemporary skull base reconstruction after resection of skull base tumors.
Methods:
A systematic literature review of English language articles by using PubMed and Ovid. Search terms included "lumbar drain," "CSF leak," and "endoscopic endonasal reconstruction." Articles were included when they pertained to adults, used current methods for reconstruction (i.e., multilayered repair or vascularized tissue), and addressed CSF leak rates secondary to endoscopic resection of skull base masses. All the studies discussed CSF leaks that resulted from traumatic-, idiopathic-, or sinus surgery-related iatrogenic causes were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.
Results:
A total of five articles met inclusion criteria. These comprised 376 endoscopic skull base tumor resection and reconstruction cases; 5.59% developed postoperative CSF leaks. A meta-analysis was conducted by incorporating three studies that met criteria based on testing for heterogeneity. The average odds ratio for postoperative CSF leak for patients who did not have an LD relative to patients who had an LD was 0.590 (95% confidence interval, 0.214-1.630). Given a p value of 0.30, the results demonstrated a lack of statistically significant improvement between patients who had an LD and patients who did not have an LD. Various details, such as the defect size and type of CSF leak, were not consistently reported among studies.
Conclusions:
Available evidence for the use of LDs in skull base surgery is of poor quality. Analysis of the literature revealed heterogenous and varied reporting in the primary literature. Further studies that include randomized controlled trials are needed.
Objective:
Perioperative lumbar drain (LD) use in the setting of endoscopic cerebrospinal fluid (CSF) leak repair is a well-established practice. However, recent data suggest that LDs may not provide significant benefit and may thus confer unnecessary risk. To examine this, we conducted a meta-analysis to investigate the effect of LDs on postoperative CSF leak recurrence following endoscopic repair of CSF rhinorrhea.
Data sources:
A comprehensive search was performed with the following databases: Ovid MEDLINE (1947 to November 2015), EMBASE (1974 to November 2015), Cochrane Review, and PubMed (1990 to November 2015).
Review method:
A meta-analysis was performed according to PRISMA guidelines.
Results:
A total of 1314 nonduplicate studies were identified in our search. Twelve articles comprising 508 cases met inclusion criteria. Overall, use of LDs was not associated with significantly lower postoperative CSF leak recurrence rates following endoscopic repair of CSF rhinorrhea (odds ratio: 0.89, 95% confidence interval: 0.40-1.95) as compared with cases performed without LDs. Subgroup analysis of only CSF leaks associated with anterior skull base resections (6 studies, 153 cases) also demonstrated that lumbar drainage did not significantly affect rates of successful repair (odds ratio: 2.67, 95% confidence interval: 0.64-11.10).
Conclusions:
There is insufficient evidence to support that adjunctive lumbar drainage significantly reduces postoperative CSF leak recurrence in patients undergoing endoscopic CSF leak repair. Subgroup analysis examining only those patients whose CSF leaks were associated with anterior skull base resections demonstrated similar results. More level 1 and 2 studies are needed to further investigate the efficacy of LDs, particularly in the setting of patients at high risk for CSF leak recurrence.
Lumbar drains were once routinely used for cerebrospinal fluid (CSF) diversion in endoscopic skull base reconstruction. The vascularized pedicled nasoseptal flap has now become the reconstructive workhorse in the setting of high-flow leaks. High-flow CSF leaks occur when there is violation of a cistern or ventricle. As lumbar drains have the potential for significant complications and the rate of postoperative CSF leak has decreased with the use of vascularized flaps, lumbar drain use has been challenged.
Lumbar drains have a reported 3% major and 5% minor complication rates. Two recent studies reviewed their postoperative CSF leak rates after reconstruction of high-flow leaks. Garcia-Navarro described 46 cases in which a lumbar drain was placed in 67% of patients with two postoperative CSF leaks, one in each group. Eloy et al. described 59 patients without lumbar drain and reported no postoperative CSF leaks.
Lumbar drains are not necessary in the settings of low-flow CSF leaks or even in all high-flow leaks. We consider the use of a lumbar drain in settings wherein a high-flow leak is encountered or anticipated and the patient has other risk factors that may make the risk of postoperative CSF leak higher or closure of the leak more difficult.
Postoperative cerebrospinal fluid (CSF) leak is a serious complication of transsphenoidal surgery, which can lead to meningitis and often requires reparative surgery. We sought to identify preoperative risk factors for CSF leaks and meningitis. We reviewed 98 consecutive expanded endoscopic endonasal surgeries performed from 2008–2012 and analyzed preoperative comorbidities, intraoperative techniques, and postoperative care. Univariate and multivariate analyses were performed. The most common pathologies addressed included pituitary adenoma, Rathke cyst, chordoma, esthesioneuroblastoma, meningioma, nasopharyngeal carcinoma, and squamous cell carcinoma. There were 11 CSF leaks (11%) and 10 central nervous system (CNS) infections (10%). Univariate and multivariate analysis of preoperative risk factors showed that patients with non-ideal body mass index (BMI) were associated with higher rate of postoperative CSF leak and meningitis (both p < 0.01). Also, patients with increasing age were associated with increased CSF leak (p = 0.03) and the length of time a lumbar drain was used postoperatively was associated with infection in a univariate analysis. In addition, three of three endoscopic transsphenoidal surgeries combined with open cranial surgery had a postoperative CSF leak and CNS infection rate which was a considerably higher rate than for transsphenoidal surgeries alone or surgeries staged with open cases (p < 0.01 and p = 0.04, respectively) In this series of expanded endoscopic transsphenoidal surgeries, preoperative BMI remains the most important preoperative predictor for CSF leak and infection. Other risk factors include age, intraoperative CSF leak, lumbar drain duration, and cranial combined cases. Risks associated with complex surgical resections when combining open and endoscopic approaches could be minimized by staging these procedures.
Objectives:
Postoperative pneumocephalus is a common occurrence after endoscopic endonasal skull base surgery (ESBS). The risk of cerebrospinal fluid (CSF) leaks can be high and the presence of postoperative pneumocephalus associated with serosanguineous nasal drainage may raise suspicion for a CSF leak. The authors hypothesized that specific patterns of pneumocephalus on postoperative imaging could be predictive of CSF leaks. Identification of these patterns could guide the postoperative management of patients undergoing ESBS.
Methods:
The authors queried a prospectively acquired database of 526 consecutive ESBS cases at a single center between December 1, 2003, and May 31, 2012, and identified 258 patients with an intraoperative CSF leak documented using intrathecal fluorescein. Postoperative CT and MRI scans obtained within 1-10 days were examined and pneumocephalus was graded based on location and amount. A discrete 0-4 scale was used to classify pneumocephalus patterns based on size and morphology. Pneumocephalus was correlated with the surgical approach, histopathological diagnosis, and presence of a postoperative CSF leak.
Results:
The mean follow-up duration was 56.7 months. Of the 258 patients, 102 (39.5%) demonstrated pneumocephalus on postoperative imaging. The most frequent location of pneumocephalus was frontal (73 [71.5%] of 102), intraventricular (34 [33.3%]), and convexity (22 [21.6%]). Patients with craniopharyngioma (27 [87%] of 31) and meningioma (23 [68%] of 34) had the highest incidence of postoperative pneumocephalus compared with patients with pituitary adenomas (29 [20.6%] of 141) (p < 0.0001). The incidence of pneumocephalus was higher with transcribriform and transethmoidal approaches (8 of [73%] 11) than with a transsellar approach (9 of [7%] 131). There were 15 (5.8%) of 258 cases of postoperative CSF leak, of which 10 (66.7%) had pneumocephalus, compared with 92 (38%) of 243 patients without a postoperative CSF leak (OR 3.3, p = 0.027). Pneumocephalus located in the convexity, interhemispheric fissure, sellar region, parasellar region, and perimesencephalic region was significantly correlated with a postoperative CSF leak (OR 4.9, p = 0.006) and was therefore termed "suspicious" pneumocephalus. In contrast, frontal or intraventricular pneumocephalus was not correlated with postoperative CSF leak (not significant) and was defined as "benign" pneumocephalus. The amount of convexity pneumocephalus (p = 0.002), interhemispheric pneumocephalus (p = 0.005), and parasellar pneumocephalus (p = 0.007) (determined using a scale score of 0-4) was also significantly related to postoperative CSF leaks. Using a series of permutation-based multivariate analyses, the authors established that a model containing the learning curve, the transclival/transcavernous approach, and the presence of "suspicious" pneumocephalus provides the best overall prediction for postoperative CSF leaks.
Conclusions:
Postoperative pneumocephalus is much more common following extended approaches than following transsellar surgery. Merely the presence of pneumocephalus, particularly in the frontal or intraventricular locations, is not necessarily associated with a postoperative CSF leak. A "suspicious" pattern of air, namely pneumocephalus in the convexity, interhemispheric fissure, sella, parasellar, or perimesencephalic locations, is significantly associated with a postoperative CSF leak. The presence and the score of "suspicious" pneumocephalus on postoperative imaging, in conjunction with the learning curve and the type of endoscopic approach, provide the best predictive model for postoperative CSF leaks.