Sinonasal Packing is Not a Requisite for Successful Cerebrospinal Fluid Leak Repair

Abstract

Background  Numerous methods have been described to repair nasal cerebrospinal fluid (CSF) leaks. Most studies have focused on optimizing CSF leak repair success, leading to closure rates of 90 to 95%.

Objective  This study aimed to determine if excellent reconstruction rates could be achieved without using sinonasal packing.

Methods  A prospective case series of 73 consecutive patients with various CSF leak etiologies and skull base defects was conducted to evaluate reconstruction success without sinonasal packing. The primary outcome measure was postoperative CSF leak. Secondary outcome measures were postoperative epistaxis requiring intervention in operating room or emergency department, infectious sinusitis, and 22-item sinonasal outcome test (SNOT-22) changes.

Results  Mean age was 54.5 years and 64% were female. Multilayered reconstructions were performed in 55.3% of cases, with collagen or bone epidural inlay grafts, and nasal mucosal grafts or nasoseptal flaps for onlay layers. Onlay-only reconstructions with mucosal grafts or nasoseptal flaps were performed in 44.7% of cases. Tissue sealants were used in all cases, and lumbar drains were used in 40.8% of cases. There were two initial failures (97.4% initial success), but both resolved with lumbar drains alone (no revision surgeries). There were no instances of postoperative epistaxis requiring intervention in the operating room or emergency department. Infectious sinusitis occurred in 2.7% of patients in the first 3 months postoperatively. SNOT-22 did not change significantly from preoperatively to first postoperative visits, then improved over time.

Conclusion  Nasal CSF leaks from various etiologies and defect sites were successfully repaired without using sinonasal packing, and patients experienced minimal sinonasal morbidity.

Introduction

Untreated nasal cerebrospinal fluid (CSF) leaks can lead to serious morbidity or mortality due to meningitis, brain abscess, pneumocephalus, and intracranial hemorrhage. ^{1 2 3 4} Nasal CSF leaks can occur spontaneously due to idiopathic intracranial hypertension or skull base tumors, or traumatically from accidental or iatrogenic trauma. Advances in endoscopic CSF leak repair, including meticulous multilayered closure and vascularized mucosal flaps, have led to success rates of 90% or higher for most CSF leak etiologies. ^{1 5 6 7 8 9 10}

Sinonasal packing is commonly utilized after CSF leak repair and endoscopic skull base surgery. Potential benefits include hemostasis, support to prevent migration of the reconstructive materials, stenting of sinus outflow tracts, and creation of an added barrier between the external environment and intracranial cavity. ¹¹ Multiple types of packing materials, techniques, and durations have been described. Nonabsorbable packing materials such as Merocel sponges (Medtronic Inc., Minneapolis, Minnesota, United States), petroleum-based strip gauze, or an inflated Foley catheter have all been described to bolster skull base reconstructions. However, practices have largely been guided by expert opinion or surgeon preference. ^{11 12 13 14} Studies have rarely assessed whether sinonasal packing contributes to the high success rates of CSF leak repair. While sinonasal packing has not been demonstrated directly to improve CSF leak repair success, it has been shown to increase patient discomfort postoperatively. ^{15 16} The purpose of this study was to determine if excellent CSF leak closure rates could be achieved without using sinonasal packing.

Materials and Methods

A prospective case series was conducted by analyzing outcomes for all adult patients who underwent endoscopic endonasal repair of anterior, middle, and posterior cranial fossa CSF leaks at Henry Ford Health System from October 2015 to August 2019. The institutional review board approved the study. CSF leak repairs were all performed by the senior author (J.R.C.), an otolaryngologist, in collaboration with a neurosurgeon (J.P.R., A.M.R.).

The following variables were recorded: age, gender, body mass index, 22-item sinonasal outcome test (SNOT-22), CSF leak etiology, skull base defect site, dural defect size, intrathecal opening pressure (for spontaneous CSF leak cases), reconstructive technique and materials, and postoperative lumbar drain (LD) use. Dural defect sizes were determined intraoperatively using a sterile ruler and were recorded as being less than or greater than 1 cm ² . Dural defects <1 cm ² were termed small, and >1 cm ² were termed large. ¹¹ In the setting of spontaneous CSF leaks, intrathecal opening pressures were typically considered elevated if they were >20 cm H ₂ O. ^{17 18} The following defect sites were included: sella, cribiform plate/fovea ethmoidalis, planum sphenoidale, other sphenoid sinus walls (lateral wall of the sphenoid sinus, roof of the lateral recess), posterior table of frontal sinus, and clivus.

Intraoperative Routine

All patients received preoperative intravenous vancomycin 1 g (or 15 mg/kg) and cefepime of 1 to 2 g (or 50 mg/kg). Intraoperatively, multilayered reconstruction was always preferred when bony defects were ≥5 mm, and defect geometry allowed inlay placement. Inlay grafts were placed in the epidural space deep into the bony edges of skull base defects between the bone and dura, and onlay grafts or flaps were placed superficial to bony defect edges. Multilayered reconstruction consisted of at least an inlay layer of porcine collagen (Biodesign, Cook Medical, Bloomington, Indiana, United States) or autologous nasal septal bone, along with a mucosal onlay layer, either as a free graft or nasoseptal flap (NSF). NSFs were always preferred for repairing large dural defects (>1 cm) when feasible. NSFs were also preferred for repairing CSF leaks due to elevated intracranial pressure (ICP) or accidental or iatrogenic traumatic leaks considered higher risk for postoperative failure due to hydrocephalus or elevated body mass index. ^{17 19} In some cases with significant dead space deep into the dura, collagen matrix (DuraGen, Integra LifeSciences, Plainsboro, New Jersey, United States) was placed to fill the intradural dead space, providing a supportive scaffold for the overlying reconstructive layers. In these scenarios, one or more pieces of collagen matrix were used to cover the dural defects, then folded as needed to fill the dead space. Fig. 1 depicts representative examples of multilayered reconstructions of small and large dural defects after skull base tumor resections. Mucosal onlay-only reconstructions were performed for some cases when inlay layers were not feasible, with either free grafts or NSFs. All reconstructions were reinforced by tissue sealants: Adherus Autospray (HyperBranch Medical Technology, Stryker, Durham, North Carolina, United States), DuraSeal (Integra LifeSciences), or Tisseel (Baxter Healthcare, Deerfield, IL). No sinus or nasal packings were used.

Fig. 1.

Representative images of examples of multilayered CSF leak repairs of small ( A, B ) and large ( C, D ) dural defects after skull base tumor resections. ( A ) Porcine collagen inlay graft placed in the epidural space deep to the edges of the sellar bony defect, as part of a multilayered closure of a small dural defect after pituitary adenoma resection. ( B ) Free nasal septal mucosal onlay graft placed over the edges of the bony defect. ( C ) Porcine collagen inlay graft placed in the epidural space of the tuberculum/planum defect, as part of the multilayered closure of a large dural defect after craniopharyngioma resection. ( D ) Nasoseptal flap placed over the edges of the bony defect. CSF, cerebrospinal fluid.

Postoperative Care

All patients were admitted to the neurosurgical intensive care unit postoperatively. Prophylactic intravenous antibiotics were administered for 24 to 48 hours to prevent intracranial infection, ²⁰ consisting of vancomycin every 12 hours (pharmacy-adjusted dose) and cefepime 1 g every 12 hours. Patients remained on bed rest with elevated head of bed to 30 degrees until ambulation. LDs were utilized after some CSF leak repairs for CSF diversion, mostly for large dural defects and elevated ICPs. LDs were clamped in the afternoon/evening of postoperative day 1. In the morning of postoperative day 2, patients ambulated, and if no CSF leak suspicion, LDs were removed.

After completing 24 to 48 hours of intravenous antibiotics, patients initially in the series received either oral amoxicillin/clavulanate or clindamycin for a total of 10 days postoperatively. Later in the series, oral antibiotics were not routinely prescribed postoperatively, unless patients had sinusitis at the time of surgery or patients had risk factors for developing postoperative infections (e.g., poorly controlled diabetes, chronic tobacco use, and primary immunodeficiency). ^{21 22} The following nasal precautions were employed for 2 weeks postoperatively perform open-mouth sneezing and coughing, and avoid straining, nose blowing, or lifting >5 pounds. Nasal saline sprays were initiated three times daily on discharge and were recommended until sinonasal cavities were mucosalized and patients had no crusting.

Patients were followed for variable durations based on their etiologies and healing of their sinonasal cavities. Patients were generally followed until they had absent sinonasal crusting or infection, and the sinuses were deemed patent to prevent sinusitis or mucocele formation. If patients were found to have purulent sinusitis postoperatively (nasal endoscopy demonstrating pus in any sinuses), they were placed on oral antibiotics for 10 days.

The primary outcome measure was CSF leak repair success. The following secondary postoperative outcome measures were also assessed: epistaxis requiring return to operating room or emergency department, sinusitis occurring <3 or >3 months postoperatively, time to absent sinonasal crusting, and changes in SNOT-22 across different CSF leak etiologies over time.

Statistical Analysis

Demographic and clinical data were tabulated for the whole patient population, and summary statistics were calculated. Postoperative SNOT-22 scores were compared with preoperative SNOT-22 for each postoperative visit using paired sample t -tests. These comparisons were made for each type of CSF leak etiology separately. Specific timeframes were used to categorize postoperative visits, with the first being 2 weeks, second being 6–8 weeks, and third being 12–16 weeks. One-way analysis of variance was used to compare median times to absent sinonasal crusting between different CSF leak etiologies (skull base tumors, spontaneous meningoencephaloceles, and trauma). Statistical significance was set at p  < 0.05. Analyses were computed using RStudio (RStudio, Boston, MA).

Results

A total of 76 skull base defects were repaired in 73 patients. Patient demographics and disease characteristics are shown in Table 1 . Mean age was 54.0 ± 15.8 years. The study included 47 females (64%). Mean body mass indices according to CSF leak etiology were as follows: skull base tumor (32.3 ± 8.1), spontaneous (37.7 ± 7.6), and traumatic (25.9 ± 7.1). For patients with spontaneous CSF leaks, median intrathecal opening pressure was 26 cm H ₂ O. Overall median follow-up duration was 8 months.

Table 1. Patient demographics.

Variables	Means ± SD or n (%) ( n  = 73)
Age (y)	54.0 ± 16
Gender n (%)
Male	26 (35.6%)
Female	47 (64.4%)
Body mass index (kg/m 2 )	32.8 ± 8.7
Skull base tumor	32.3 ± 8.1
Meningoencephalocele	37.6 ± 7.6
Traumatic	25.9 ± 7.1
Preoperative SNOT-22	32.4 ± 23.6
Skull base tumor	22.3 ± 20.6
Meningoencephalocele	43.6 ± 19.3
Iatrogenic trauma	35.2 ± 31.0
Accidental trauma	49.0 ± 41.0
Follow-up duration (mo)	8 (4, 12) (Median, IQR)

Abbreviations: BMI, body mass index; CSF, cerebrospinal fluid leak; IQR, interquartile range; SD, standard deviation; SNOT-22, 22-item sinonasal outcome test.

Of the 76 skull base defects, 38 were due to skull base tumors (50.0%), 24 meningoencephaloceles (31.6%), 8 iatrogenic trauma (10.5%), and 6 accidental trauma (7.9%). Three patients had bilateral skull base defects (two meningoencephaloceles and one iatrogenic from endoscopic sinus surgery). Of the 38 skull base tumors, 13 were large dural defect repairs (34.2%). Regarding CSF leak locations, the majority were located at the sella (32.9%), cribiform plate/ethmoid (28.9%), or planum/tuberculum regions (21.1%). Other less common sites included other sphenoid walls (7.9%), frontal sinus posterior (3.9%), and clivus (1.3%). See Table 2 for details.

Table 2. Frequencies of the different CSF leak etiologies and locations repaired in this study.

Variables	Frequencies ( n  = 76) n (%)
CSF leak etiology
Skull base tumor	38 (50.0)
Large dural defect (≥1 cm 2 )	25 (65.8)
Small dural defect (<1 cm 2 )	13 (34.2)
Meningoencephalocele	24 (31.6)
Iatrogenic trauma	8 (10.5)
Accidental trauma	6 (7.9)
CSF leak location
Sella	25 (32.9)
Cribriform plate/fovea ethmoidalis	22 (28.9)
Planum/tuberculum	16 (21.1)
Other sphenoid sinus walls (lateral wall and lateral recess)	6 (7.9)
Posterior table of frontal sinus	3 (3.9)
Clivus	1 (1.3)

Abbreviation: CSF, cerebrospinal fluid.

Table 3 shows the frequencies with which the different CSF leak etiologies were repaired by onlay-only or multilayered reconstructions, as well as the reconstructive materials used. Multilayer reconstructions were performed in 55.3% of cases (42/76), while mucosal onlay-only reconstructions were performed in 44.7% of cases (34/76). Overall, free mucosal grafts were used for 50 defects and were obtained from the following sites: nasal septum (35), nasal floor (15), and middle turbinate (1). NSFs were used for 26 defects. For multilayered reconstructions, porcine collagen was used as the inlay graft in 92.9% of cases (39/42), and septal bone in 7.1% (3/42).

Table 3. CSF leak repair techniques used according to CSF leak etiologies.

Variables	Total ( n  = 76)	Skull base tumor, small dural defect ( n  = 25)	Skull base tumor, large dural defect ( n  = 13)	Spontaneous encephalocele ( n  = 24)	Traumatic ( n  = 14)
Onlay-only reconstruction	34	6 (24.0%)	2 (15.4%)	13 (54.2%)	13 (92.9%)
Free mucosal graft	25	5/6	1/2	6/13	13/13
NSF	9	1/6	1/2	7/13	0
Multilayer reconstruction	42	19 (76.0%)	11 (84.6%)	11 (45.8%)	1 (7.1%)
Inlay graft
Porcine collagen	39	19/19	11/11	8/11	1/1
Septal bone	3	0/19	0/11	3/11	0
Onlay tissue
Free mucosal graft	25	18/19	3/11	4/11	0/14
NSF	17	1/19	8/11	7/11	1/14
Preinlay DuraGen	23	11 (44.0%)	11 (84.6%)	0 (0%)	1 (7.1%)
Lumbar drain	31	4/25 (16%)	9/13 (69.2)	17 (70.1%)	1 (7.1%)
Initial postoperative failures	2	1/25 (4%)	1/13 (7.7%)	0 (0%)	0 (0%)

Abbreviations: CSF, cerebrospinal fluid; NSF, nasoseptal flap.

In 23 of the sellar, suprasellar, and clival tumor resections, substantial intracranial dead space was partially obliterated with DuraGen to provide a supporting scaffold for the inlay and onlay layers. Dural sealants were used to reinforce the mucosal onlay layers in all cases, consisting of Adherus ( n  = 46), Tisseel ( n  = 15), or DuraSeal ( n  = 12). LDs were used in 31 cases: 70.1% of spontaneous CSF leaks with elevated ICPs (17/24), 69.2% of skull base tumors with large dural defects (9/13), and 16% of skull base tumors with small defects (4/25). Postoperative oral antibiotics were continued in 76.7% of patients (56/73), with 48 of the first 50 patients receiving them, and 8 of the last 26 patients.

There was a 97.4% initial CSF leak repair success rate. Two patients had confirmed CSF leaks by β-2 transferrin testing in the first 2 to 3 days postoperatively. Clinical features of these two patients are highlighted in Table 4 . The first patient developed a postoperative CSF leak on postoperative day 2 on ambulation, after multilayered repair of a low-flow CSF leak during transsphenoidal pituitary adenoma resection. The second patient developed a postoperative CSF leak on postoperative day 3 after 24 hours of ambulation. She had undergone a multilayered closure of a high-flow CSF leak incurred during a transplanum approach to resect a Rathke's cleft cyst. Both patients resolved with LD diversion alone. The LDs were placed by a neurosurgeon postoperatively because neither patient had a LD placed prophylactically before surgery.

Table 4. Characteristics of the two patients with initial CSF leak repair failures.

Variables	Patient 1	Patient 2
Age (y)	73	65
Gender	Male	Female
Body mass index (kg/m 2 )	23.6	34.6
Pathology	Pituitary adenoma	RCC
Location	Sella	Planum/tuberculum
Revision surgery	No	No
Dural defect size	Small (<1 cm 2 )	Large (≥1 cm 2 )
Preinlay DuraGen	No	Yes
Inlay layer	Porcine collagen	Porcine collagen
Onlay layer	Free septal mucosal graft	NSF
Dural sealant	Adherus	Adherus
Initial LD CSF diversion	No	No
Time to postoperative failure (B2-Tf positive rhinorrhea)	Postoperative day 2	Postoperative day 3
Duration of lumbar drainage	5 days	4 days
Return to operating room?	No	No

Abbreviations: B2-Tf, beta-2 transferrin; CSF, cerebrospinal fluid; LD, lumbar drain; NSF, nasoseptal flap; RCC, Rathke's cleft cyst.

Regarding secondary outcomes, there were no instances of postoperative epistaxis requiring intervention in the operating room or emergency department. There were two instances of purulent sinusitis requiring oral antibiotics within the first 3 months postoperatively (2.7%), and five instances of sinusitis after 3 months (6.8%). Each episode resolved after one 10-day course of oral antibiotics. Sinonasal crusting resolved at a median of 2.5 months, and there was no significant difference in time to crusting resolution between CSF leak etiologies ( p  = 0.700). Lastly, for all CSF leak etiologies, patients had no significant changes in SNOT-22 scores from preoperative to their first follow-up visit at 2 weeks after surgery. While SNOT-22 scores trended downward thereafter in all groups, there were only significant decreases noted at second and third postoperative visits for spontaneous CSF leak patients ( Table 5 ; Fig. 2 ).

Table 5. Changes in SNOT-22 postoperatively for each of the cerebrospinal fluid leak etiologies.

Post-op visit	Skull base tumor (SNOT-22 change)	p -Value	Encephalocele (SNOT-22 change)	p -Value	Iatrogenic traumatic (SNOT-22 change)	p -Value	Accidental traumatic (SNOT-22 change)	p -Value
Post-op 1	+11	0.160	−12	0.100	−19	0.280	−6	1.000
Post-op 2	+0.5	0.210	−11	0.030	−14.5	0.110	−14	N/A
Post-op 3	0	0.500	−18.5	0.030	−20.5	0.120	−26.5	N/A

Abbreviations: N/A, not available; Post-op, postoperative; SNOT-22, 22-item sinonasal outcome test.

Notes: Post-op 1: 2 weeks; Post-op 2: 6–8 weeks; Post-op 3: 12–16 weeks.

N/A: too few data to calculate.

Fig. 2.

Change in 22-item sinonasal outcome test (SNOT-22) postoperatively after endoscopic repair of various cerebrospinal fluid leak etiologies. The changes from preoperatively to first postoperative visits were not statistically significant for any of the patients.

Discussion

A multitude of techniques have been described to achieve CSF leak closure rates around 90% or higher. ^{1 4 6 7 23 24 25} While studies have generally focused on whether specific types of reconstruction lead to higher CSF leak repair success, less attention has been placed on utility of sinonasal packing and reducing patient morbidity. While the main goal of this study was to achieve excellent CSF leak closure rates without using sinonasal packing, sinonasal morbidity was also analyzed and compared with previous publications on CSF leak repair.

A systematic review and meta-analysis in 2000 by Hegazy et al reported nasal packing being used in 61% of the cases analyzed (125/204), but packing did not have a significant effect on surgical outcome. ³ No other studies have compared packing to no packing for CSF leak repair. With regard to sinonasal morbidity, Little et al showed that placing nasal splints or absorbable nasal packing was associated with decreased quality of life in the immediate postoperative period and up to 3 months postoperatively. ¹⁵ Other studies have demonstrated an association between packing use and increased mucopurulence and patient discomfort in the acute postoperative period. ^{15 16 26 27} Other potential risks with intranasal packing include sinusitis, toxic-shock syndrome, and the potential side effects from the prophylactic oral antibiotics generally recommended for indwelling nasal packing. ^{14 28} Lastly, if a Foley's balloon packing is used, in addition to discomfort from the inflated balloon, patients may be at risk for a nasopulmonary bradycardic reflex and could require cardiac monitoring until the Foley's removal. ¹⁴

In the current study, CSF leak repair was performed without using sinonasal packing, and a 97.4% success rate was achieved with a 0% revision surgery rate. These results would suggest that packing is not absolutely necessary for CSF leak repair success. The high success rate can be attributed to previously established endoscopic surgical techniques, and possibly LD use and tissue sealants. Patients in this study underwent onlay-only or multilayered reconstructions of a variety of CSF leak etiologies in several different skull base locations. Interestingly, while multilayered reconstruction was preferred, it was only performed in 55% of cases, generally due to small (<5 mm) or irregular bony defects, or an inadequate epidural space after dural resection.

Multilayer reconstructions were more likely to be performed after skull base tumor resections (75–85% of cases). With regard to onlay layers, while an NSF was preferred for large dural defects, it was only used in 61.5% of those cases, either due to flap unavailability or inappropriate skull base defect geometry. Also of note, after skull base tumor resections, 24% of small and 15% of large dural defects were repaired by onlay grafts or flaps alone, and none of these repairs failed. With regard to spontaneous and traumatic CSF leaks, the majority of these cases were repaired with free onlay grafts only, and none of these repairs failed. While this study's sample size was too small to draw definitive conclusions, especially for large dural defects, this is encouraging for the preliminary data that packing does not necessarily facilitate CSF leak closure, regardless of etiology. However, whether multilayered closure improves outcomes or not when not using packing requires further study.

One possible explanation for the success of CSF leak repair in this study without the use of packing materials could be the use of LDs which were used in approximately 70% of CSF leaks due to large dural defects or elevated ICPs. Some studies have shown benefit in utilizing LDs for diversion to improve high-flow CSF leak repair success, ^{8 25 29} whereas others have suggested that LDs may not impact high-flow CSF leak repair outcomes. ^{30 31 32 33 34 35} Interestingly, these LD studies make it difficult to draw conclusions on the utility of sinonasal packing because they either reported using packing in all patients, reported the use of packing variably, or did not report the use of nasal packing. It is therefore unclear and would require further study to determine whether the success of high-flow CSF leak repair is contingent on some form of additional support through either LD diversion or external pressure from packing.

Another important point to discuss is the potential issue with providing no bolstering of a free mucosal graft in the immediate postoperative period. As free grafts have no direct vascular supply, they obtain nutrition initially through imbibition. ³⁶ It would be intuitive that pressure application to the graft would promote contact between the mucosa and underlying bone, prevent submucosal hematoma, and optimize the wound healing environment until the graft becomes vascularized by surrounding tissue. Kim et al showed that free mucosal grafts integrated into the bone over sellar defects with mucosal enhancement on contrasted magnetic resonance imaging equivalent to surrounding mucosa at 3 months postoperatively. They used absorbable packing material in the sphenoid. ³⁷ A similar study utilizing no sinonasal packing, and earlier contrasted imaging after surgery would be interesting to assess free graft vascularity. While further study is necessary to understand free graft wound healing physiology, the results from the current study suggest that graft bolstering is not absolutely necessary.

Another point to discuss is tissue sealant use, as there is limited evidence on its utility in CSF leak repair. In this study, every reconstruction was supported with one of three different tissue sealants. Eloy et al reported no benefit from Tisseel, DuraSeal, or Evicel (OMRIX Biopharmaceuticals Ltd, Ramat Gan, Israel) after repair of 42 high-flow CSF leaks compared with 32 high-flow leaks without sealant use in a retrospective study. ³⁸ However, they did not report the frequency of each sealant used, and these sealants have different biochemical and mechanical properties. Adherus is a newer hydrogel dural sealant, has a higher burst strength than DuraSeal, ³⁹ and has been shown to be noninferior to DuraSeal for dural repair with regard to postoperative CSF leak rate. ⁴⁰ Adherus was used to reinforce repairs in the majority of patients in this study. Adherus was used in both patients with postoperative CSF leaks, but the failure rate was too small for statistical analysis. Prospective studies will be necessary to determine whether tissue sealants, or specific types of tissue sealants, affect CSF leak repair outcomes.

Secondary aims of this study were to evaluate whether patients had any significant postoperative complications or quality-of-life alterations that could be explained by the avoidance of sinonasal packing. First, there were no instances of postoperative epistaxis requiring emergency or operative intervention, suggesting that packing would not confer any additional benefit in preventing postoperative nasal hemorrhage. Similarly, other studies have demonstrated no significant benefit from nasal packing in preventing postoperative epistaxis after endoscopic sinus surgery. ^{26 41} Second, there was a 2.7% incidence of postoperative purulent sinusitis in the first 3 months after CSF leak repair. Note that the use of antibiotics for 10 days postoperatively did not appear to prevent the development of sinusitis in the first 3 months after surgery, since the two patients who developed sinusitis had received antibiotics. Additionally, four of the five patients who developed sinusitis after 3 months, had received antibiotics in the immediate postoperative period. While the authors would still advocate for 24 to 48 hours of prophylactic intravenous antibiotics to prevent intracranial infection after CSF leak repair, longer antibiotic duration does not seem to confer added protection from sinusitis when sinonasal packing is avoided. This would be one additional advantage of foregoing sinonasal packing, as prolonged prophylactic oral antibiotics could be avoided in most cases.

With regard to crusting, median time to absent crusting in this study was 2.5 months, similar to the findings by de Almeida et al in their series of 63 patients. ⁴² Note that they did not report whether packing was used or not, so whether packing affects the time to crusting resolution requires further study. Trends in SNOT-22 scores were also interesting compared with previous publications, in which there were no significant changes in SNOT-22 from preoperative to first follow-up visits at 2 weeks postoperatively. Multiple studies have demonstrated initial increases in SNOT-22 at the first postoperative visit after endoscopic skull base surgery, followed by gradual improvements over time. ^{43 44 45} Of these studies, two utilized some form of nasal packing consistently, whereas one systematic review did not report frequency of nasal packing utilized. Taken with the findings from Little et al, which revealed decreased quality of life in the immediate postoperative period in association with nasal splints and packing. ¹⁵ The current study suggests that avoiding sinonasal packing may lead to better sinonasal quality of life in the initial postoperative period after CSF leak repair.

One significant limitation of this series was the small number of large dural defects, and specifically clival defects. Closure of large dural and clival defects have been reported to have higher failure rates. ^{1 6 7 8 17 23} While one could argue that sinonasal packing may be more important in these high-flow CSF leak cases, the aforementioned articles did not discuss the use of sinonasal packing. While the current study showed high success rates without using packing, there could be situations where packing could help maintain water-tight closures, such as with large dural defects and no LD use, and these decisions should be left to surgeon discretion. Another limitation of the study was the study's heterogeneous population of CSF leak etiologies and skull base defect locations which limited the sample size of each entity. However, given the high success rate of CSF leak repair without sinonasal packing, it would be very difficult to obtain a sample size large enough to compare packing versus no packing with regard to leak repair success, and to compare outcomes based on leak etiology and location.

Conclusion

Based on the current series, CSF leak repair of various etiologies and at various locations can be highly successful without the use of sinonasal packing. Closure of CSF leaks from large dural defects was also highly successful without sinonasal packing but with concurrent LD use in a majority of those cases. Avoiding sinonasal packing may lead to less of a decrement to sinonasal quality of life in the immediate postoperative period, without causing any additional risk of epistaxis or sinusitis. In the absence of evidence showing improved CSF leak closure specifically due to sinonasal packing, the potential morbidity of packing could outweigh its possible benefits in certain cases.