A Unique Case of Bilateral Recurrent Sphenoid Sinus Cerebrospinal Fluid Leaks: Primary Acquired Leak Within the Lateral Sphenoid Sinus Recess, Followed by a Leak via Sternberg's Canal

Sternberg's Canal and Defect: Is the Lateral Craniopharyngeal Canal a Source of Spontaneous Cerebrospinal Fluid Leak? Anatomic and Radiological Analysis in Pediatric and Adult Populations

BACKGROUND

The lateral craniopharyngeal or Sternberg's canal (SC) originates from superior orbital fissure (SOF) and traverses the sphenoid body into the nasopharynx. A remnant of the canal, Sternberg's defect (SD), has been debated as a source of cerebrospinal fluid (CSF) leak. The canal was described in 1888, and there is limited accurate visual illustration in the literature.

OBJECTIVE

To provide a detailed anatomic and radiological illustration of the canal in pediatric and adult population including the mechanism undermining the incidence of the canal, and the possibility of the canal as a source of CSF leak.

METHODS

A total of 195 high-resolution computed tomographies (CT) of patients (50 3-yr-old, 20 5-yr-old, and 125 adults) and 43 dry adult skulls (86 sides) were analyzed for a canal matching the description of the SC.

RESULTS

A SC was identified in 86% of the 3-yr-old and 40% of 5-yr-old patients. The diameter and length were 2.12 mm and 12 mm, respectively. The incidence of the canal decreased with age as sinus pneumatization extended into the sphenoid sinus. Only 0.8% of the adult skull on CT had the canal. The canal was not present on the dry adult skulls examination, but SD was found in 4.65%.

CONCLUSION

SC exists with high incidence in the pediatric group. Sinus pneumatization obliterates the canal in the adult population, leaving a defect in 4.65% of cases, which given the location and related anatomic structures, is unlikely to be a source of CSF leak.

A Unique Subset: Idiopathic Intracranial Hypertension Presenting as Spontaneous CSF Leak of the Anterior Skull Base

Introduction Spontaneous cerebrospinal fluid (CSF) leaks represent a unique clinical presentation of idiopathic intracranial hypertension (IIH), lacking classical features of IIH, including severe headaches, papilledema, and markedly elevated opening pressures.

Methods Following a single-institution retrospective review of patients undergoing spontaneous CSF leak repair, we performed a literature review of spontaneous CSF leak in patients previously undiagnosed with IIH, querying PubMed.

Results Our literature review yielded 26 studies, comprising 716 patients. Average age was 51 years with 80.8% female predominance, and average body mass index was 35.5. Presenting symptoms included headaches (32.5%), visual disturbances (4.2%), and a history of meningitis (15.3%). Papilledema occurred in 14.1%. An empty sella was present in 77.7%. Slit ventricles and venous sinus stenosis comprised 7.7 and 31.8%, respectively. CSF leak most commonly originated from the sphenoid sinus (41.1%), cribriform plate (25.4%), and ethmoid skull base (20.4%). Preoperative opening pressures were normal at 22.4 cm H2O and elevated postoperatively to 30.8 cm H2O. 19.1% of patients underwent shunt placement. CSF leak recurred after repair in 10.5% of patients, 78.6% involving the initial site. A total of 85.7% of these patients were managed with repeat surgical intervention, and 23.2% underwent a shunting procedure.

Conclusion Spontaneous CSF leaks represent a distinct variant of IIH, distinguished by decreased prevalence of headaches, lack of visual deficits, and normal opening pressures. Delayed measurement of opening pressure after leak repair may be helpful to diagnose IIH. Permanent CSF diversion may be indicated in patients exhibiting significantly elevated opening pressures postoperatively, refractory symptoms of IIH, or recurrent CSF leak.

Endoscopic Endonasal Transpterygoid Approach to Sphenoid Sinus Lateral Recess Defects

Background  Lesions affecting sphenoid sinus lateral recess (SSLR) are difficult to visualize and manipulate through the transnasal routes, especially when the sinus is highly pneumatized. External approaches to this area involve extensive surgery and are associated with significant morbidity. The aims of this study are to present our experience with the endoscopic transpterygoid approach as a method for approaching lesions of the SSLR and to evaluate the outcomes of this procedure. Methods  Clinical charts of patients who had lesions in the SSLR and who were treated at our institution from September 1998 to June 2018 were retrospectively reviewed. All these patients were managed by the endoscopic endonasal transpterygoid approach. Results  Thirty-nine patients were identified. No cerebrospinal fluid leak recurrences were observed during follow-up (range: 1-19.7 years; median: 2.3 years). Hypoesthesia (temporary, 1; persistent, 4) in the region innervated by the maxillary branch of the trigeminal nerve was detected in five (12.8%) patients, while symptoms due to the Vidian nerve damage (dry eye, 3; dry nasal mucosa, 1) were present in four (10%) patients. Conclusions  Although the endoscopic endonasal transpterygoid approach is an excellent corridor for dealing with lesions of the SSLR, limited rate of neurologic and lacrimal complications was observed. Potential morbidity of the intervention should be discussed during preoperative counselling.

Management of sphenoid lateral recess encephalocoeles

PURPOSE OF REVIEW

Sphenoid sinus lateral recess encephalocoeles (SSLRE) are rare occurrences and pose unique challenges due to limited surgical access for endoscopic endonasal repair and also the lack of consensus on optimal perioperative managements specifically in the spontaneous cases, which are also believed to be a variant of idiopathic intracranial hypertension (IIH). Endoscopic endonasal approaches have largely replaced the transcranial route and the techniques are continuously being refined to reduce the neurovascular morbidity and improve outcome.

RECENT FINDINGS

Transpetrygoid is the most utilized approach with modifications suggested to limit bone removal, exposure and preservation of the neurovascular structures as dictated by the extent of the lateral recess. As more experience is gained, extended transphenoidal techniques were also successfully used for access. Lateral transorbital is a new approach to the lateral recess investigated in cadavers. IIH treatment is still controversial in the setting of SSLRE, but it appears rationale to evaluate, monitor and treat if necessary.

SUMMARY

SSLRE management should be tailored to the specific anatomical variances and cause. Modifications of techniques have been described giving different options to access the lateral recess. Successful repair for spontaneous SSLRE may require treatment of IIH if present, but the long-term outcome is still unclear.

A Systematic Review of Secondary Cerebrospinal Fluid Leaks

Background

Secondary cerebrospinal leaks (CSF) are leaks that recur after an initial endoscopic repair of CSF leaks. Identification of characteristics that could predict secondary leaks may allow surgeons to plan repairs with the knowledge that these defects are more likely to fail.

Objective

To identify characteristics that could predict secondary CSF leaks.

Methods

A search of all studies that reported outcomes after endoscopic repair of CSF leaks was conducted by using medical literature data bases. Studies with the following criteria were included: written in the English language, secondary CSF leaks after primary repair, and assessment of success of fistula repair. Data extracted included the etiology of the leak, site of the leak, reconstructive materials used, and success of the repair.

Results

Ninety-four studies, from 1988 to 2015, with a total of 3149 primary CSF leaks were included. Sixty-three studies (67%) had a success rate of ≥80%; 77 studies (82%) had secondary leak rates of <40%. For 88 of the 94 studies (94%), the success rate after secondary repair improved to 81.0–100%. Of 48 studies that included leaks of more than one site, the sphenoid was the most common site of leak in 26 studies (55%), the ethmoid was the most common site in 16 studies (34%), and the cribriform was the most common site in 11 studies (23%).

Conclusion

The rate of secondary CSF leaks was low due to advances in endoscopic repair techniques. Spontaneous and iatrogenic CSF leaks were more likely to recur, especially without adequate control of underlying factors, such as increased intracranial pressure and obesity. Further studies with consistent reporting are required for more definitive conclusions about secondary CSF leaks.

Ethmoidal meningoencephalocele and CSF leak after posthaemorrhagic ventricular dilatation in a newborn child

BACKGROUND

Rhinoliquorrhoea suggests a communication between the subarachnoid space and the sinonasal tract. Clinical presentation includes clear nasal discharge, headache, pneumocephalus, meningitis or brain abscess. Cerebrospinal fluid (CSF) leaks are mostly of traumatic origin (skull base fractures), iatrogenic (secondary to endoscopic endonasal surgery) or associated with tumour aetiology. Occasionally, hydrocephalus has been the cause of rhinoliquorrhoea in adults, presumably secondary to the chronically raised intracranial pressure with skull base erosion and meningocele. To our knowledge, the association of hydrocephalus and ethmoid meningoencephalocele/CSF leak has not been previously reported in a newborn child.

CASE PRESENTATION

We present the case of a 9-month-old girl who was referred for rhinorrhoea. She had a history of posthaemorrhagic ventricular dilatation. Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed a left ethmoidal meningoencephalocele and small ventricular size. The meningoencephalocele was surgically repaired using an intradural subfrontal approach. During the postoperative period, after the transient lumbar drain was withdrawn, she developed symptomatic hydrocephalus. Ventriculoperitoneal shunting was required.

CONCLUSION

Progressive ventricular dilatation may arise from a meningoencephalocele/CSF leak in paediatric patients. Early identification and repair of the meningoencephalocele are critical to avoid development of complications.