The Surgical Treatment of Posttraumatic Skull Base Defects with Cerebrospinal Fluid Leak

Indirect Fistula: A New Terminology for Cerebrospinal Fluid Fistula With Different 'Apparent Origin' and 'Real Origin'

Fistulas are abnormal communications between body cavities. They can occur between the CNS and the extracranial space, presenting clinically as CSF leaks. Due to the variety of features, multiple classifications have been implemented to better study this pathology. A systematic review was conducted using the Scopus, Medline, and Web of Science databases. Observational studies such as cohort studies, case reports, case series, cross-sectional studies, systematic reviews, and publications that assess the classification of CSF leaks were included. The systematic review identified 29 publications that met the required criteria for inclusion. Although the primary focus of most of these publications was not on classification, they briefly mentioned it. The included publications describe classifications according to etiology, exiting flow pressure, anatomic site, and some new classification proposals. Of the 29 included studies, 11 referred to the appearance of CSF rhinorrhea or otorrhea with no relationship between the cause or site of origin and the site of the CSF leak. However, none of these publications names this situation. These results clearly indicate that a term for this circumstance needs to be established; none of the previously listed publications provide a name for this condition. This systematic review aims to demonstrate the necessity of implementing a new term to describe CSF leaks where the 'apparent origin' does not correspond to the 'real origin.' The results show no existing term that considers such cases; therefore, we propose the term 'Indirect Fistula' to designate these cases.

Management of Traumatic and Non-Traumatic Cerebrospinal Fluid Rhinorrhea-Experience from Three Southeast Asian Countries

BACKGROUND

Cerebrospinal fluid (CSF) rhinorrhea requires proper management to avoid disastrous consequences. The objectives of this study were to ascertain the patient characteristics, etiologies, sites of defect, skull base configurations, methods of investigation, and management outcomes of CSF rhinorrhea.

METHODS

A retrospective study was performed over 4 years involving three surgeons from Malaysia, Singapore, and Thailand. Hospital records were reviewed to determine the patients' characteristics, the causes and sites of leaks, methods of investigation, skull base configurations, choices of treatment, and outcomes.

RESULTS

A total of 15 cases (7 traumatic and 8 non-traumatic) were included. Imaging was performed in all cases. The most common site of leakage was the cribriform plate (9/15 cases). The mean ± SD of the Keros heights were 4.43 ± 1.66 (right) and 4.21 ± 1.76 mm (left). Type II Keros was the most common (60%). The mean ± SD angles of the cribriform plate slope were 51.91 ± 13.43 degrees (right) and 63.54 ± 12.64 degrees (left). A class II Gera configuration was the most common (80%). All except two patients were treated with endonasal endoscopic surgical repair, with a success rate of 92.3%. A multilayered repair technique was used in all patients except one. The mean ± SD postoperative hospital stay was 9.07 ± 6.17 days.

CONCLUSIONS

Non-traumatic CSF rhinorrhea outnumbered traumatic CSF rhinorrhea, with the most common site of leak at the cribriform plate. Imaging plays an important role in investigation, and Gera classification appears to be better than Keros classification for evaluating risk. Both conservative and surgical repairs are practiced with successful outcomes. Endonasal endoscopic CSF leak repair is the mainstay treatment.

Endoscopic endonasal approaches for reconstruction of traumatic anterior skull base fractures and associated cerebrospinal fistulas: patient series

BACKGROUND

Post-traumatic cerebrospinal fluid (CSF) leaks of the anterior skull base may arise after traumatic brain injury (TBI). Onset of CSF rhinorrhea may be delayed after TBI and without prompt treatment may result in debilitating consequences. Operative repair of CSF leaks caused by anterior skull base fractures may be performed via open craniotomy or endoscopic endonasal approaches (EEAs). The authors' objective was to review their institutional experience after EEA for repair of TBI-related anterior skull base defects and CSF leaks.

OBSERVATIONS

A retrospective review of prospectively collected data from a major level 1 trauma center was performed to identify patients with TBI who developed CSF rhinorrhea. Persistent or refractory post-traumatic CSF leaks and anterior skull base defects were repaired via EEA in four patients. Intrathecal fluorescein was administered before EEA in three patients (75%) to help aid identification of the fistula site(s). CSF leaks were eventually repaired in all patients, though one reoperation was required. During a mean follow-up of 8.75 months, there were no instances of recurrent CSF leakage.

LESSONS

Refractory, traumatic CSF leaks may be effectively repaired via EEA using a multilayer approach and nasoseptal flap reconstruction, thereby potentially obviating the need for additional craniotomy in the post-TBI setting.

The mini-combined transpetrosal approach: an anatomical study and comparison with the combined transpetrosal approach

BACKGROUND

The combined transpetrosal approach (CTPA) is a versatile technique suitable for challenging skull base pathologies. Despite the advantages provided by a wide surgical exposure, the soft tissue trauma, complex and time-consuming bony work, and cosmetic issues make it far from patient expectations. In this study, the authors describe a less invasive modification of the CTPA, the mini-combined transpetrosal approach (mini-CTPA), and perform a quantitative comparison between these two approaches.

METHODS

Five human specimens were used for this study. CTPA was performed on one side and mini-CTPA on the opposite side. The surgical freedom, petroclival and brainstem area of exposure, and maneuverability for 6 anatomical targets, provided by the CTPA and mini-CTPA, were calculated and statistically compared. The bony volumes corresponding to each anterior petrosectomy were also measured and compared. Three clinical cases with an operative video are also reported to illustrate the effectiveness of the approach.

RESULTS

The question-mark skin incision done along the muscle attachments permits an optimal cosmetic result. Even though the limited incision, the smaller craniotomy, and the less extensive bone drilling of mini-CTPA provide a smaller area of surgical freedom, the areas of exposure of petroclival region and brainstem were not statistically different between the two approaches. The antero-posterior maneuverability for the oculomotor foramen (OF), Meckel's cave (MC) and the REZ of trigeminal nerve, and the supero-inferior maneuverability for OF, MC, Dorello's canal, and REZ of CN VII are significantly reduced by the smaller opening. The bony volume of anterior petrosectomy resulted similar among the approaches.

CONCLUSIONS

The mini-CTPA is an interesting alternative to the CTPA, providing comparable surgical exposure both for petroclival region and for brainstem. Although the lesser soft tissue dissection and bony opening decrease the surgical maneuverability, the mini-CTPA may reduce surgical time, potential approach-related morbidities, and improve cosmetic and functional outcomes for the patients.

Imaging of Acquired Skull Base Cerebrospinal Fluid Leaks

Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. The initial assessment of rhinorrhea or otorrhea which is suspected to be due to an acquired skull base CSF leak requires integration of clinical assessment and biochemical confirmation of CSF. Imaging with high-resolution CT is performed to locate osseous defects, while high-resolution T2w MRI may detect CSF traversing the dura and bony skull base. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to invasive cisternography may be necessary.

The Role of Endonasal Endoscopic Skull Base Repair in Posttraumatic Tension Pneumocephalus

OBJECTIVES

Information about the endonasal endoscopic approach (EEA) for the management of posttraumatic tension pneumocephalus (PTTP) remains scarce. Concomitant rhinoliquorrhea and posttraumatic hydrocephalus (PTH) can complicate the clinical course.

METHODS

The authors systematically reviewed pertinent articles published between 1961 and December 2020 and identified 6 patients with PTTP treated by EEA in 5 reports. Additionally, the authors share their institutional experience including a seventh patient, where an EEA resolved a recurrent PTTP without rhinoliquorrhea.

RESULTS

Seven PTTP cases in which EEA was used as part of the treatment regime were included in this review. All cases presented with a defect in the anterior skull base, and 3 of them had concomitant rhinoliquorrhea. A transcranial approach was performed in 6/7 cases before EEA was considered to treat PTTP. In 4/7 cases, the PTTP resolved after the first intent; in 2/7 cases a second repair was necessary because of recurrent PTTP, 1 with and 1 without rhinoliquorrhea, and 1/7 case because of recurrent rhinoliquorrhea only. Overall, PTTP treated by EEA resolved with a mean radiological resolution time of 69 days (range 23-150 days), with no late recurrences. Only 1 patient developed a cerebrospinal fluid diversion infection probably related to a first incomplete EEA skull base defects repair. A permanent cerebrospinal fluid diversion was necessary in 3/7 cases.

CONCLUSIONS

Endonasal endoscopic approach repair of air conduits is a safe and efficacious second-line approach after failed transcranial approaches for symptomatic PTTP. However, the strength of recommendation for EEA remains low until further evidence is presented.

Evaluation of the safety and effectiveness of a sealant hemostatic patch for preventing cerebrospinal fluid leaks in cranial surgery

BACKGROUND

Cerebrospinal fluid (CSF) leak remains a significant source of morbidity after neurosurgical procedures. The objective is to evaluate the effectiveness and safety of a polyethylene glycol-coated collagen patch (PCC) in different neurosurgical procedures.

METHODS

A retrospective, single-center cohort study in patients who underwent a cranial neurosurgical procedure. After collecting multiple data variables, patients were divided into two groups depending on the use of PCC as sealant on dural closure following procedures.

RESULTS

Data from 230 patients were collected (PCC, 128; control group, 102). Incidence of CSF leakage was significantly lower in the PCC group (p < .001). Complications that were significantly lower in PCC than the control group included surgical infection (p = .022), and hydrocephalus (p = .017), as well as reduced rates of reintervention (p < .001) and shorter hospital stays (p = .028). Factors associated with a higher incidence of CSF leakage included posterior fossa procedures, reinterventions, and the need for CSF drainage placement. PCC reduced the risk of suffering CSF leakage by more than 75% (p = .002) once adjusted for age, surgical approach, type of cranial opening, reintervention, CSF drainage, dural substitute, and dural defect coverage.

CONCLUSIONS

Our findings confirm PCC as an effective means of preventing CSF leakage following cranial neurosurgery with fewer associated complications.

Treatment of traumatic cerebrospinal fluid rhinorrhea via extended extradural anterior skull base approach

OBJECTIVE

To describe and assess the repair technique and perioperative management for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture via extradural anterior skull base approach.

METHODS

This was a retrospective review conducted at the Department of Neurosurgery of the Shanghai Tenth People's Hospital from January 2015 to April 2020. Patients with traumatic CSF rhinorrhea resulting from extensive anterior skull base fracture treated surgically via extended extradural anterior skull base approach were included in this study. The data of medical and radiological records, surgical approaches, repair techniques, peritoperative management, surgical outcome and postoperative follow-up were analyzed. Surgical repair techniques were tailored to the condition of associated injuries of the scalp, bony and dura injuries and associated intracranial lesions. Patients were followed up for the outcome of CSF leak and surgical complications. Data were presented as frequency and percent.

RESULTS

Thirty-five patients were included in this series. The patients' mean age was 33 years (range 11-71 years). Eight patients were treated surgically within 2 weeks; while the other 27 patients, with prolonged or recurrent CSF rhinorrhea, received the repair surgery at 17 days to 10 years after the initial trauma. The mean overall length of follow-up was 23 months (range 3-65 months). All the patients suffered from frontobasal multiple fractures. The basic repair tenet was to achieve watertight seal of the dura. The frontal pericranial flap alone was used in 20 patients, combined with temporalis muscle and/or its facia in 10 patients. Free fascia lata graft was used instead in the rest 5 patients. No CSF leak was found in all the patients at discharge. There was no surgical mortality in this series. Bilateral anosmia was the most common complication. At follow-up, no recurrent CSF leak or meningitis occurred. No patients developed mucoceles, epidural abscess or osteomyelitis. One patient ultimately required ventriculoperitoneal shunt because of progressive hydrocephalus.

CONCLUSION

Traumatic CSF rhinorrhea associated with extensive anterior skull base fractures often requires aggressive treatment via extended intracranial extradural approach. Vascularized tissue flaps are ideal grafts for cranial base reconstruction, either alone or in combination with temporalis muscle and its fascia---fascia lata sometimes can be opted as free autologous graft. The approach is usually reserved for patients with traumatic CSF rhinorrhea in complex frontobasal injuries.

Endonasal Endoscopic and Hybrid Surgery Techniques for Blunt Trauma Fractures of the Skull Base With Cerebrospinal Fluid Leaks

ABSTRACT

Cerebrospinal fluid (CSF) leakage caused by skull base fracture represents high risks of bacterial meningitis, and a rate of mortality of 8.9%. Endoscopic endonasal repair of CSF leaks is quite safe and effective procedure with high rates of success. The aim of this study is to describe our technique for management of skull base CSF leaks secondary to craniofacial trauma based on the anatomic location of the leak. This is a retrospective case series of 17 patients with diagnosis of craniofacial trauma, surgically treated with sole endonasal endoscopic and combined endonasal/transcranial approaches with diagnosis of CSF leak secondary to skull base fractures. Seventeen patients met inclusion criteria for this study. Mean age was 46 years old. Most common etiology was motor vehicle. Early surgery was performed in 8 patients, and late surgery in 9 patients. The most common site of CSF leak was at ethmoid cells or at the fronto-ethmoid junction in 9 patients. Thirteen patients (76.4%) were treated only with endonasal endoscopic technique, and 4 (23.5%) with hybrid surgery, combining endonasal endoscopic and cranial bicoronal approaches with nasal and pericranial vascularized flaps, and nasal mucosal free flaps. Mean hospital stay was 23.7 days.The mean follow-up time was 25.6 months. When surgical reconstruction is indicated for CSF leaks secondary to skull base fractures, endonasal endoscopic techniques should be part of the surgical management either as a sole procedure, or in combination with classical transcranial approaches with high rates of success and low morbidity.

Decreased Incidence of CSF Leaks after Skull Base Fractures in the 21st Century: An Institutional Report

Objectives Cerebrospinal fluid (CSF) leaks are a possible complication in patients with skull base fractures (SBFs). The widely cited incidence of CSF leaks is 10 to 30% in SBF patients; however, this estimate is based only on a few outdated studies. A recent report found CSF leaks in <2% SBF patients, suggesting the incidence may be lower now. To investigate this, we report here our institutional series.

Design This study is a retrospective chart review.

Setting The study was conducted at two major academic medical centers (2000–2018).

Participants Adult patients with SBF were included in this study.

Main Outcome Measures Variables included age, gender, CSF leak within 90 days, management regimen, meningitis within 90 days, and 1-year mortality.

Results Among 4,944 patients with SBF, 199 (4%) developed a CSF leak. SBF incidence was positively correlated with year of clinical presentation (r-squared 0.78, p < 0.001). Among CSF leaks, 42% were conservatively managed, 52% were treated with lumbar drain, and 7% required surgical repair. Meningitis developed in 28% CSF leak patients. The 1-year mortality for all SBF patients was 11%, for patients with CSF leaks was 12%, and for patients with meningitis was 16%.

Conclusion In the largest institutional review of SBF patients in the 21st century, we found CSF leak incidence to be 4%. This is lower than the widely cited range of 10 to 30%. Nevertheless, morbidity and mortality associated with this complication remains clinically significant, and SBF patients should continue to be monitored for CSF leaks. We provide here our institutional treatment algorithm for these patients that may help to inform the treatment strategy at other institutions.