**6. Surgical Intervention**

Endoscopic repair of CSF leaks is effective and offers decreased morbidity compared to open approaches. Meticulous technique is key to success in repair of skull base defects. Materials used and procedures employed are less important than the quality of the repair [6].

Advancements in the endoscopic surgical repair of CSF leaks and encephaloceles have resulted from improvements in instrumentation, visualization, access, and technique. Improved diagnostic imaging and surgical navigation have also improved management. Advancements in endoscopic reconstructive techniques of the skull base including utilization of local vascularized flaps have improved success rates with endoscopic approaches [7].

Compared to open surgery, the endoscopic approach allows for more direct visualization with less manipulation of the surrounding soft tissues. This may allow for a more precise reconstruction of the skull base due to better visualization, and minimal manipulation of nearby neurovascular structures. Compared to the traditional microscopic view, endoscopes give a dynamic operative view with the added ability to see around corners using angled endoscopes. ESBS can avoid scars, decrease hospital stays, and cause less postoperative pain [8].

Not all areas of the skull base can be visualized and safely instrumented via a transnasal endoscopic route. As a general rule, the endoscopic approach should not compromise the ability to achieve the appropriate reconstruction, and crossing major neurovascular structures is not suggested [9].

Common complications from skull base surgery include anosmia and associated taste dysfunction, epistaxis and neurologic complications such as cranial nerve injury. Major skull base surgery complications include CSF rhinorrhea, meningitis, intracranial hemorrhage, orbital complications such as diplopia or vision loss, vascular injury, stroke, and death [8–11].

Intrathecal fluorescein is often used in the surgical repair of CSF leaks. Its advantages include the ability to stain defects that may be more difficult to identify clinically, through the visible dye of CSF to a light green color. The surgeon can also use it to confirm a water-tight repair. It carries a 0% false positive rate. Its disadvantages include a moderate false negative result. It requires a lumbar puncture, and the use of fluorescein intrathecally is not FDA-approved. Rare complications including seizures (0.3%) and death have been reported; however, these have more commonly been associated with administration through a suboccipital puncture. If used to help localize a CSF leak it should be used with caution and should be dosed as 0.05–0.1 mL per 10 kg body weight up to maximum 0.1 mL 10% fluorescein. This is mixed in 10 mL of preservative-free normal saline or CSF. The surgeon should inject slowly (over 5–10 min) without paralytics in the anesthetic regimen to assess for seizure activity. Fluorescein should be avoided in patients with abnormal renal function [12].

The primary goal in endoscopic repair of CSF leaks and skull base reconstruction is to definitively identify all leaks in order to completely reconstruct all defects. After identifying the leak or leaks, the goals of reconstruction are creation of a safe barrier with separation of intracranial and sinonasal spaces and elimination of any dead space. As with any surgical intervention, meticulous surgical technique is paramount for success.

A reconstructive ladder should be used to help determine the type of repair performed. For simple, small (less than 1 cm) defects, a fat plug harvested from the earlobe or abdomen can be used to plug the defect. The next option includes a simple overlay graft harvested from the nasal floor mucosa, turbinate mucosa, or nasal septum. If a more complex, larger reconstruction is in order, a composite (underlay and overlay) graft can be used consisting of an intracranial underlay of bone or cartilage from nasal septum, auricular cartilage or turbinate bone, and an overlay graft of mucosa (free or pedicled) as above. Local pedicled flaps should include the nasoseptal flap, which is supplied by the posterior nasal septal artery, a terminal branch of the sphenopalatine artery. Additional grafts that can be useful in larger defects include temporal fascia or tensor fascia lata grafts. These grafts are

**131**

*Cerebrospinal Fluid Leaks and Encephaloceles DOI: http://dx.doi.org/10.5772/intechopen.91374*

drainage is also up to surgeon discretion.

antibiotics in some form after surgery.

**7. Conclusion**

pneumocephalus.

skull base may be necessary.

often bolstered in the sinonasal cavity with abdominal fat, a nasoseptal flap or both. In complex situations of extensive defects or poor local tissue, such as in chemoradiated patients, a craniotomy with pericranial flap or free flap reconstruction of the

Lumbar drains are often used to decrease intracranial pressure and thereby reduce the pressure applied to the skull base reconstruction; however, they may be associated with significant morbidity and potential for complications. The use of lumbar drain primarily following a repair varies from different surgeons, and should not be universally utilized in a routine fashion. When used, the duration of

Most reconstructive methods appear to have similar efficacy, and therefore there is no universal "best type of reconstruction." In general, small defects (<1 cm) can be closed in a single layer, and multilayer repair is preferred for larger defects. Some surgeons prefer to use a rigid layer of bone or cartilage to reconstruct the skull base, although this is not required [13]. Vascularized mucosal tissue (e.g., nasoseptal flap) has been demonstrated to improve repair results for larger defects; however, single

Postoperative antibiotics are an important consideration for skull base surgery because of the temporary connection between the intracranial space and external world. Rates of postoperative wound infection following ESBS are approximately 2%, and appear to be higher in open skull base surgery. Broad coverage with IV cephalosporins with or without vancomycin (or oral amoxicillin/clavulanate) is most often recommended. Studies are lacking to support the use of prolonged postoperative antibiotics, although most surgeons prefer to use systemic or topical

A multitude of studies over the past 25 years have shown high success rates of primary repair around 90%, and secondary repair around 97%. These success rates compare favorably to traditional craniotomy approaches with reported success rates between 70 and 80% that carry a higher morbidity profile. Symptoms of failure in reconstruction include clear rhinorrhea and constant postnasal drip. Other signs may include meningitis, severe headaches, seizures, and worsening

layer nonvascularized tissue can also be successful in this setting.

#### *Cerebrospinal Fluid Leaks and Encephaloceles DOI: http://dx.doi.org/10.5772/intechopen.91374*

*Sino-Nasal and Olfactory System Disorders*

rates with endoscopic approaches [7].

Advancements in the endoscopic surgical repair of CSF leaks and encephaloceles have resulted from improvements in instrumentation, visualization, access, and technique. Improved diagnostic imaging and surgical navigation have also improved management. Advancements in endoscopic reconstructive techniques of the skull base including utilization of local vascularized flaps have improved success

Compared to open surgery, the endoscopic approach allows for more direct visualization with less manipulation of the surrounding soft tissues. This may allow for a more precise reconstruction of the skull base due to better visualization, and minimal manipulation of nearby neurovascular structures. Compared to the traditional microscopic view, endoscopes give a dynamic operative view with the added ability to see around corners using angled endoscopes. ESBS can avoid scars,

Not all areas of the skull base can be visualized and safely instrumented via a transnasal endoscopic route. As a general rule, the endoscopic approach should not compromise the ability to achieve the appropriate reconstruction, and crossing

Common complications from skull base surgery include anosmia and associated

taste dysfunction, epistaxis and neurologic complications such as cranial nerve injury. Major skull base surgery complications include CSF rhinorrhea, meningitis, intracranial hemorrhage, orbital complications such as diplopia or vision loss,

Intrathecal fluorescein is often used in the surgical repair of CSF leaks. Its advantages include the ability to stain defects that may be more difficult to identify clinically, through the visible dye of CSF to a light green color. The surgeon can also use it to confirm a water-tight repair. It carries a 0% false positive rate. Its disadvantages include a moderate false negative result. It requires a lumbar puncture, and the use of fluorescein intrathecally is not FDA-approved. Rare complications including seizures (0.3%) and death have been reported; however, these have more commonly been associated with administration through a suboccipital puncture. If used to help localize a CSF leak it should be used with caution and should be dosed as 0.05–0.1 mL per 10 kg body weight up to maximum 0.1 mL 10% fluorescein. This is mixed in 10 mL of preservative-free normal saline or CSF. The surgeon should inject slowly (over 5–10 min) without paralytics in the anesthetic regimen to assess for seizure activity. Fluorescein should be avoided in patients with abnormal renal

The primary goal in endoscopic repair of CSF leaks and skull base reconstruction is to definitively identify all leaks in order to completely reconstruct all defects. After identifying the leak or leaks, the goals of reconstruction are creation of a safe barrier with separation of intracranial and sinonasal spaces and elimination of any dead space. As with any surgical intervention, meticulous surgical technique is

A reconstructive ladder should be used to help determine the type of repair performed. For simple, small (less than 1 cm) defects, a fat plug harvested from the earlobe or abdomen can be used to plug the defect. The next option includes a simple overlay graft harvested from the nasal floor mucosa, turbinate mucosa, or nasal septum. If a more complex, larger reconstruction is in order, a composite (underlay and overlay) graft can be used consisting of an intracranial underlay of bone or cartilage from nasal septum, auricular cartilage or turbinate bone, and an overlay graft of mucosa (free or pedicled) as above. Local pedicled flaps should include the nasoseptal flap, which is supplied by the posterior nasal septal artery, a terminal branch of the sphenopalatine artery. Additional grafts that can be useful in larger defects include temporal fascia or tensor fascia lata grafts. These grafts are

decrease hospital stays, and cause less postoperative pain [8].

major neurovascular structures is not suggested [9].

vascular injury, stroke, and death [8–11].

**130**

function [12].

paramount for success.

often bolstered in the sinonasal cavity with abdominal fat, a nasoseptal flap or both. In complex situations of extensive defects or poor local tissue, such as in chemoradiated patients, a craniotomy with pericranial flap or free flap reconstruction of the skull base may be necessary.

Lumbar drains are often used to decrease intracranial pressure and thereby reduce the pressure applied to the skull base reconstruction; however, they may be associated with significant morbidity and potential for complications. The use of lumbar drain primarily following a repair varies from different surgeons, and should not be universally utilized in a routine fashion. When used, the duration of drainage is also up to surgeon discretion.

Most reconstructive methods appear to have similar efficacy, and therefore there is no universal "best type of reconstruction." In general, small defects (<1 cm) can be closed in a single layer, and multilayer repair is preferred for larger defects. Some surgeons prefer to use a rigid layer of bone or cartilage to reconstruct the skull base, although this is not required [13]. Vascularized mucosal tissue (e.g., nasoseptal flap) has been demonstrated to improve repair results for larger defects; however, single layer nonvascularized tissue can also be successful in this setting.

Postoperative antibiotics are an important consideration for skull base surgery because of the temporary connection between the intracranial space and external world. Rates of postoperative wound infection following ESBS are approximately 2%, and appear to be higher in open skull base surgery. Broad coverage with IV cephalosporins with or without vancomycin (or oral amoxicillin/clavulanate) is most often recommended. Studies are lacking to support the use of prolonged postoperative antibiotics, although most surgeons prefer to use systemic or topical antibiotics in some form after surgery.
