Diaphragm reconstruction using a TachoSil patch as alternative to intrasellar packing for small focal diaphragm defects in pituitary surgery: a cohort study.

BACKGROUND: During pituitary surgery, CSF leaks are often treated by intrasellar packing, using muscle or fat grafts. However, this strategy may interfere with the interpretation of postoperative MRI and may impact the quality of resection in cases of second surgery, due to the existence of additional fibrous tissue. We present an alternative technique, using a diaphragm reconstruction with a heterologous sponge combining fibrinogen and thrombin (TachoSil), applied in selected patients with low-flow CSF leaks. This study investigates the surgical outcome of patients treated with this strategy. METHODS: From a cohort of 2231 patients treated from June 2011 to June 2023 by endoscopic endonasal approach for pituitary surgery, the surgical technique of diaphragm repair with TachoSil patch performed in 55 patients (2.6%) was detailed, and the rate of closure failure was analyzed at 6 months postoperatively. No intrasellar packing was used and sellar floor reconstruction was performed whenever possible. The rate of postoperative CSF leak was compared with that reported in three previous publications that also used the TachoSil patch technique. RESULTS: Patients were mostly women (F/M ratio: 1.2) with a median age of 53.6 years. Surgery was indicated for non-functioning adenomas, Cushing's disease, acromegaly, and Rathke's cleft cysts in 38/55 (69.1%), 6/55 (10.9%), 5/55 (9.1%) and 6/55 (10.9%) patients respectively. The rate of postoperative CSF leak was 1.8% (n = 1/55), which was not significantly different from that reported in the three cohorts from the literature (2.8%, p > 0.05). No postoperative meningitis was recorded. CONCLUSIONS: In highly selected patients with low-flow CSF leaks related to small focal diaphragm defects, diaphragm reconstruction using a TachoSil patch can be a safe and valuable alternative to intrasellar packing.

Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view.

PURPOSE: Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored. MATERIALS AND METHODS: A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development. RESULTS: 192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004). CONCLUSIONS: Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

Spontaneous Cerebrospinal Fluid Leak in a Patient with Asymptomatic Idiopathic Intracranial Hypertension.

BACKGROUND: Spontaneous cerebrospinal fluid (CSF) leaks occur when there is a tear in the dura mater. Spontaneous CSF leaks are rare, and often associated with conditions like intracranial hypertension, connective tissue disorders, or congenital defects in the dura mater. CASE REPORT: The patient was a 66-year-old woman who presented to the Emergency Department with clear, positional nasal discharge from her left nostril for 1 week. She had a history of chronic headaches, which seemed to have been relieved around the time of onset of her rhinorrhea. Diagnostic imaging, including computed tomography and magnetic resonance imaging scans, confirmed the presence of a CSF leak and a left temporal meningoencephalocele. The patient subsequently underwent surgical repair of the leak and ventriculoperitoneal shunt placement, and was discharged home in stable condition. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Early detection of CSF leaks require a thorough history and physical examination, and is crucial in preventing potentially life-threatening complications such as meningitis and intracranial abscesses.

Ventriculoperitoneal Shunt Alone for Spontaneous Cerebrospinal Fluid Rhinorrhea as a Presenting Symptom of Hemi-hydranencephaly.

A 27-year-old female patient presented with chronic spontaneous cerebrospinal fluid (CSF) rhinorrhea. She had deformity and weakness on the left side since childhood. Imaging examinations demonstrated hemi-hydranencephaly with a nearly complete absence of the right cerebral hemisphere, which was replaced with a membranous sac filled with CSF. She was accompanied with a frontal midline tumor containing lipids. After ventriculoperitoneal shunt, the CSF rhinorrhea completely ceased and no direct repair of the CSF fistula was necessary. The ventriculoperitoneal shunt procedure changes the CSF flow dynamics and releases the intracranial pressure, which may be a simple and effective procedure for CSF rhinorrhea in hemi-hydranencephaly.

Endoscopic Repair of Cerebrospinal Fluid Rhinorrhea Due to Trauma by a Bamboo Stick in a Pediatric Patient.

Cerebrospinal fluid rhinorrhea (CSFR) is a condition in which the cerebrospinal fluid flows out of the nasal cavity due to rupture of the arachnoid, dura, and nasal membranes because of bone defects in the skull base. The authors report a rare case of CSFR in a 2-year-old girl who experienced trauma in the nasal cavity by a bamboo stick. She underwent endoscopic repair for the CSFR. During surgery, a bulged vesicle was observed at the left cribriform plate with a small amount of cerebrospinal fluid draining from the surrounding area. Postoperative recovery was good. Endoscopic CSFR repair in pediatric patients is minimally invasive, effective, and safe as demonstrated in this case. Prevention of CSFR in children is important. Parents and caretakers of children need to be more aware, and potentially dangerous objects should not be kept within reach of children.

A Novel Nasal Endoscopy-Assisted Method for Sealing Cerebrospinal Fluid Rhinorrhea.

Cerebrospinal fluid (CSF) rhinorrhea is one of the most common complications after trans-sphenoidal surgery. At present, transcranial or endoscopic surgery for CSF leakage requires general anesthesia to remove autologous fat or fascia to repair the leak, which is traumatic and costly. The authors present a case of a 25-year-old male patient with pituitary adenoma who experienced CSF rhinorrhea 10 days after undergoing endoscopic resection of the tumor. The authors innovatively sequential filled the leak with a gelatin sponge soaked in povidone-iodine solution and iodinated gauze under outpatient nasal endoscopy. The follow-up of 6 months showed no recurrence of CSF leakage. CSF leakage is the most common complication of trans-sphenoidal surgery. The authors suggest that for small cerebrospinal fluid leaks in the early stage after trans-sphenoidal surgery, the leakage should be first filled with gelatin sponge and iodoform gauze sequentially under outpatient nasal endoscopy, which may achieve a complete cure.

Aetiology of cerebrospinal fluid rhinorrhoea in a Dutch retrospective cohort from two tertiary referral centres.

BACKGROUND: Cerebrospinal fluid (CSF) rhinorrhoea has different aetiologies, with spontaneous leaks related to female gender and obesity. Limited data is available on patient characteristics and surgical outcomes across different aetiologies of CSF leaks in relatively non-obese populations. METHODS: Retrospective cohort study from two tertiary referral centres including adult patients that underwent surgical closure of a CSF leak, divided into four aetiologies: traumatic, iatrogenic, secondary to structural intracranial pathology (SIP), and spontaneous. Data included patient characteristics, presenting symptoms, preoperative radiologic findings, intracranial pressure (ICP) and surgical outcomes. RESULTS: 72 patients were included: 9 traumatic, 15 iatrogenic, 4 SIP and 44 spontaneous leaks. Primary surgical success was 79%, rising to 93% with reinterventions. Spontaneous leak cases displayed highest female proportion and BMI. A meningo(-encephalo)cele was present in 33 patients and was associated with surgical failure and previous meningitis. No significant differences were observed between different aetiologies regarding patient characteristics, presenting symptoms, or surgical success rates. CONCLUSIONS: Even in a relatively non-obese population, the majority of CSF leaks is spontaneous and associated with female gender and obesity. Otherwise, no differences exist across aetiologies regarding patient characteristics, presenting symptoms or surgical success.

Clinical and technical factors in endoscopic skull base surgery associated with reconstructive success.

BACKGROUND: In this study, we identified key discrete clinical and technical factors that may correlate with primary reconstructive success in endoscopic skull base surgery (ESBS). METHODS: ESBS cases with intraoperative cerebrospinal fluid (CSF) leaks at four tertiary academic rhinology programs were retrospectively reviewed. Logistic regression identified factors associated with surgical outcomes by defect subsite (anterior cranial fossa [ACF], suprasellar [SS], purely sellar, posterior cranial fossa [PCF]). RESULTS: Of 706 patients (50.4% female), 61.9% had pituitary adenomas, 73.4% had sellar or SS defects, and 20.5% had high-flow intraoperative CSF leaks. The postoperative CSF leak rate was 7.8%. Larger defect size predicted ACF postoperative leaks; use of rigid reconstruction and older age protected against sellar postoperative leaks; and use of dural sealants compared to fibrin glue protected against PCF postoperative leaks. SS postoperative leaks occurred less frequently with the use of dural onlay. Body-mass index, intraoperative CSF leak flow rate, and the use of lumbar drain were not significantly associated with postoperative CSF leak. Meningitis was associated with larger tumors in ACF defects, nondissolvable nasal packing in SS defects, and high-flow intraoperative leaks in PCF defects. Sinus infections were more common in sellar defects with synthetic grafts and nondissolvable nasal packing. CONCLUSIONS: Depending on defect subsite, reconstructive success following ESBS may be influenced by factors, such as age, defect size, and the use of rigid reconstruction, dural onlay, and tissue sealants.

Conventional clinical signs and symptoms are poor predictors of postoperative cerebrospinal fluid leak: A single-centre cohort perspective.

BACKGROUND: Postoperative cerebrospinal fluid (CSF) leak remains a concerning complication of the endoscopic endonasal approach (EEA) for skull base pathology. Signs and symptoms suggesting CSF leak often trigger additional workup during the postoperative course. We systematically evaluate associations between subjectively reported clinical signs/symptoms noted during the immediate postoperative period and incidence of postoperative CSF leaks. METHODS: Retrospective chart review was conducted at a tertiary academic medical centre including 137 consecutive patients with intraoperative CSF leak during EEA with primary repair between July 2018 and August 2022. Postoperative CSF leak associations with clinical signs and symptoms were evaluated using positive (PPV) and negative predictive values (NPV), sensitivity, specificity and odds ratio (OR) via univariate logistic regression. RESULTS: Seventy-nine patients (57.7%) had high-flow leaks repaired and 5 (3.6%) developed CSF leaks postoperatively. Of reported symptoms, rhinorrhea was most common (n = 52, 38.0%; PPV [95% CI] = 7.6% [4.8%, 11.9%]), followed by severe headache (n = 47, 34.3%; 6.3% [3.1%, 12.5%]), dizziness (n = 43, 31.4%; 2.3% [0.4%, 12.1%]), salty or metallic taste (n = 20, 14.6%; 9.9% [3.3%, 25.8%]), and throat drainage (n = 10, 7.3%; 9.9% [1.7%, 41.4%]). Nausea or vomiting constituted the most reported sign concerning for CSF leak (n = 73, 53.3%; PPV [95% CI] = 4.1% [2.0%, 8.1%]). On univariate regression, no sign or symptom, including rhinorrhea (OR [95% CI] = 7.00 [0.76-64.44]), throat drainage (3.42 [0.35-33.86]), salty/metallic taste (4.22 [0.66-27.04]), severe headache (3.00 [0.48-18.62]), dizziness (0.54 [0.06-4.94]), fever (3.16 [0.50-19.99]), and nausea/vomiting (1.33 [0.22-8.21]), associated with postoperative CSF leak. CONCLUSIONS: A range of subjectively reported symptoms and signs failed to predict postoperative CSF leak. Further investigation is warranted to inform appropriate attention and response.

[Endoscopic endonasal anterior skull base surgery : Presentation of a monocentric entity profile]. / Endonasal-endoskopische anteriore Schädelbasischirurgie : Darstellung eines monozentrischen Entitätenprofils.

BACKGROUND: 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 a lower complication profile compared to open skull base surgery, the therapeutic results are comparable if the indications are correct. MATERIALS AND METHODS: 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. RESULTS: A total of 50 cases 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 grade III or higher according to Clavien-Dindo occurred in 4/50 cases. During the observation period, n = 5 olfactory neuroblastomas were diagnosed, all of which were exclusively and successfully operated on endoscopically. CONCLUSION: 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.

Spontaneous rhinorrhea and idiopathic intracranial hypertension: a complex and challenging association.

INTRODUCTION: Spontaneous CSF leak is a known complication of idiopathic intracranial hypertension (IIH). Patients with CSF rhinorrhea present a unique challenge within the IIH population, as the occurrence of a leak can mask the typical IIH symptoms and signs, complicating the diagnosis. Treatment of leaks in this population can also be challenging, with the risk of rhinorrhea recurrence if intracranial hypertension is not adequately treated. OBJECTIVE: The aim of this narrative review was to examine current literature on the association between spontaneous CSF rhinorrhea leaks and IIH, focusing on key clinical features, diagnostic approaches, management strategies, and outcomes. MATERIAL AND METHODS: A literature search was executed using the PubMed and Scopus databases. The search was confined to articles published between January 1985 and August 2023; extracted data was then analysed to form the foundation of the narrative review. RESULTS: This search yielded 26 articles, comprising 943 patients. Average age was 46.8 ± 6.5 years, and average body mass index was 35.8 ± 4.8. Most of the patients were female (74.33%). Presenting symptoms were rhinorrhea, headaches and meningitis. The most common imaging findings were empty sella and encephalocele. The standard treatment approach was endoscopic endonasal approach for correction of CSF rhinorrhea leak, and shunt placement was also performed in 128 (13%) patients. Recurrences were observed in 10% of cases. CONCLUSIONS: The complex relationship between spontaneous CSF leaks and IIH is a challenge that benefits from multidisciplinary evaluation and management for successful treatment. Treatments such as endoscopic repair, acetazolamide, and VP/ /LP shunts reduce complications and recurrence. Personalised plans addressing elevated intracranial pressure are crucial for successful outcomes.

Spontaneous skull base cerebrospinal fluid leak during pregnancy: a case report and review of the literature.

BACKGROUND: Idiopathic intracranial hypertension can lead to dural defects and spontaneous leakage of cerebrospinal fluid (CSF) from the skull base. Skull base CSF leaks are rarely reported in pregnancy but pose unique challenges for obstetricians and anesthesiologists. CASE PRESENTATION: A 31-year-old G4P1021 at 14 weeks developed debilitating headaches and CSF rhinorrhea. Brain imaging revealed a bony defect of the sphenoid sinus with a meningoencephalocele and a partially empty sella, consistent with CSF leakage from a skull base defect. The patient was neurologically stable without signs of meningitis; thus, management was focused on symptomatic alleviation. A planned cesarean section was performed at 38 weeks under spinal anesthesia. The patient had spontaneous marked improvement of her symptoms postpartum. CONCLUSION: Pregnancy may exacerbate skull base CSF leaks, requiring careful management with a multidisciplinary team. Neuraxial anesthesia can safely be performed in pregnant individuals with spontaneous skull base CSF leakage, but further studies are needed to determine the safest mode of delivery in these patients.

Spinal pseudomeningocele closure: capsulofascial interposition technique.

INTRODUCTION: The development of a spinal pseudomeningocele is a complication of dural repair or reconstruction that carries significant morbidity for pediatric patients. In addition to cerebrospinal fluid (CSF) hypotension and positional headaches, CSF leaking into the extradural space increases the risk for incisional breakdown, meningitis, and cosmetic deformity. Spinal pseudomeningocele management is challenging, and reported techniques range from local wound revisions/exploration to shunt placement for permanent CSF diversion. METHODS: At our institution, we have recently implemented a multidisciplinary approach of capsulofascial interposition for the surgical repair of the symptomatic spinal pseudomeningocele with a combined neurosurgery-plastic surgery team. To our knowledge, this technique has not previously been characterized, and we describe the technical aspects of this surgery here. RESULTS: Among 10 patients treated with this technique, none required reoperation or developed infections following pseudomeningocele closure; 2 patients received postoperative transfusions; and 2 patients underwent CSF diversion procedures. CONCLUSION: We propose that this capsulofascial interposition technique should be employed in the surgical treatment of symptomatic spinal pseudomeningoceles.

Rapid ossification of a giant post-operative occipital pseudomeningocele following posterior fossa surgery.

Pseudomeningocele formation following posterior fossa surgery is a well-recognised complication, occurring in up to 33% of operated cases in some series. Ossification of a cranial pseudomeningocele is, however, an exceptionally rare event with only three prior reported cases. We present the unique case of a paediatric patient who developed rapid ossification of a giant occipital pseudomeningocele following posterior fossa surgery. An 8-year-old female patient underwent a midline posterior fossa craniotomy for resection of an exophytic brainstem low-grade glioma. Post-surgery, the patient developed pan-ventricular hydrocephalus and a large occipital pseudomeningocele, which initially increased in size despite a successful endoscopic third ventriculostomy (ETV) being performed. At approximately 3 months post-surgery, reduction of the pseudomeningocele was observed with associated prominent ossification of the pseudomeningocele wall on computed tomography (CT) imaging. Surgical excision was subsequently undertaken, and intra-operatively, a large ossified pseudomeningocele was found. Follow-up MRI 1 month later demonstrated almost complete resolution of the pseudomeningocele with an associated reduction in the degree of pan-ventricular ventriculomegaly. This case highlights that ossification of even giant pseudomeningoceles can occur over a time period of just a few months and clinicians should consider ossification whenever a change in size or consistency of a post-operative pseudomeningocele is encountered.

How I do it? Endoscopic endonasal transpterygoid repair of sphenoid lateral recess cerebrospinal fluid leak after previous unsuccessful transcranial surgery.

BACKGROUND: Direct access to the sphenoid lateral recess offers the best chance of sealing spontaneous cerebrospinal fluid (CSF) rhinorrhea caused by lateral sphenoid encephaloceles of the Sternberg canal defect. METHOD: We present a case of spontaneous left-sided sphenoid lateral recess CSF leak after previous unsuccessful transcranial surgery managed with an endoscopic endonasal transpterygoid approach (EETA). An anatomical-based step-by-step illustration of the EETA was presented in the surgical video. CONCLUSION: This case demonstrates the value of endoscopic endonasal transpterygoid corridor in the exposure and manipulation of the sphenoid lateral recess.

Spontaneous cerebrospinal fluid rhinorrhea associated with an incidental pituitary adenoma.

Spontaneous cerebrospinal fluid (CSF) rhinorrhea presenting as the sole symptom of untreated pituitary adenoma is rare, with only 15 cases having been reported in the English literature. All these untreated pituitary adenoma contributing to spontaneous CSF rhinorrhea were diagnosed by the preoperative neuroimaging. Herein, we described an extraordinary rare patient with a pituitary microadenoma, presenting with spontaneous CSF rhinorrhea as the sole symptom. However, this pituitary microadenoma was only found incidentally at surgery, not preoperatively. To the best knowledge of us, this is the first reported case of spontaneous CSF rhinorrhea associated with an untreated pituitary adenoma diagnosed at surgery.

Spontaneous Cerebrospinal Fluid Rhinorrhea in a Patient With Breast Cancer.

Despite the well documented increased risk of osteopenia in patients with breast cancer during chemotherapy and endocrine therapy, spontaneous cerebrospinal fluid rhinorrhea (CSFR) is still rare. The authors present a case of spontaneous CSFR that occurred during chemotherapy and endocrine therapy for breast cancer. The patient underwent a repair using myofascia and adipose tissue and was started on mannitol. There was no recurrence at 1-year follow-up. Therefore, clinicians should pay attention to the possibility of CSFR in patients with breast cancer, to avoid misdiagnosis.

[Autologous fibrin glue for endoscopic skull base repair in patients with cerebrospinal fluid leakage]. / Primenenie autologichnogo fibrinovogo kleya v endoskopicheskoi plastike defektov osnovaniya cherepa pri nazal'nykh likvoreyakh.

The main stages of endoscopic skull base repair in patients with cerebrospinal fluid (CSF) leakage are identification of bone boundaries of the fistula and its closure by auto- and allografts. Fibrin glue can be used to fix plastic materials and additionally seal skull base defect. OBJECTIVE: To analyze efficacy and safety of Vivostat autologous fibrin glue for endoscopic skull base repair in patients with nasal CSF leakage and to compare postoperative outcomes after defect closure by Vivostat fibrin glue and allogeneic fibrin glue. MATERIAL AND METHODS: A retro- and prospective analysis included 56 patients with nasal CSF leakage who were treated at the Burdenko Neurosurgery Center between January 2021 and June 2022. Patients were divided into 2 groups: Vivostat fibrin glue (n=27, 48.2%) and allogeneic fibrin glue (n=29, 51.8%). Demographic and clinical perioperative data were analyzed. RESULTS: No early postoperative recurrence of CSF leakage was registered in both groups, whereas meningitis occurred in 2 cases in each group. Recurrent CSF leakage in delayed postoperative period occurred in 1 patient (3.4%) of the control group (p>0.05). Incidence of perioperative complications, subfebrile temperature in early postoperative period, surgery time and hospital-stay were similar. CONCLUSION: Vivostat autologous fibrin glue is a safe and effective method for fixing the grafts in endoscopic skull base repair. The advantages of this approach are easy application, elimination of the risk of allergic, immunological and infectious complications, as well as acceleration of tissue regeneration.

Case report: Meningoencephalocele and recurrent bacterial meningitis in chronic idiopathic intracranial hypertension.

BACKGROUND: Meningoencephalocele is a rare malformation caused by congenital and acquired lesions. The association between recurrent bacterial meningitis and meningoencephaloceles with cerebrospinal fluid (CSF) leak is reported in the literature. We report a rare case of meningoencephalocele secondary to chronic idiopathic intracranial hypertension as a result of hospitalization repeatedly for meningitis due to the lack of CSF leak. CASE PRESENTATION: This study presents a case of a patient with a decade of recurrent meningitis. With clinical symptoms and imaging examination with chronic idiopathic intracranial hypertension, this patient was diagnosed with meningoencephalocele. With the treatment of acetazolamide to decrease CSF product, the patient had no recurrence of meningitis over the 6-months follow-up period. CONCLUSION: In patients with recurrent intracranial infections but no history of immunodeficiency, cranial trauma, or neurosurgery, the possibility of meningitis should be considered appropriately, even in the absence of CSF otorrhea or rhinorrhea.

Management of postoperative CSF rhinorrhea after retrosigmoid craniotomy: how I do it.

BACKGROUND: Cerebrospinal fluid (CSF) rhinorrhea as a complication of retrosigmoid craniotomy does not occur often today. This complication is primarily associated with the petrous bone drilling during surgery. METHOD: The management of this complication is shown by the example of the patient with a trigeminal schwannoma located in posterior cranial fossa operated through resrisigmoid craniotomy. Three steps of management and surgical stages of petrous bone plasty are shown. CONCLUSION: CSF rhinorrhea after retrosigmoid craniotomy is a preventable complication: petrous bone pneumatization should be evaluated preoperatively. If the air cells are open, primary plasty of the defect should be performed.