Key points

Introduction

Endoscopic endonasal skull base reconstruction has evolved considerably over the past few decades with improved surgical techniques and sophisticated technological advancements of surgical instrumentation. To maximize the success of the skull base defect reconstruction, it is important that the postoperative course is equally insightful to reduce complications such as postoperative cerebrospinal fluid (CSF) leak and meningitis. Despite its critical importance, a standardized regimen for the management of patients after endoscopic skull base surgery is unavailable, and evidence for “optimal postoperative care” is lacking in the current literature. This article reviews the described methods and evidence on the postoperative management of patients after endoscopic skull base reconstruction.

Introduction

Endoscopic endonasal skull base reconstruction has evolved considerably over the past few decades with improved surgical techniques and sophisticated technological advancements of surgical instrumentation. To maximize the success of the skull base defect reconstruction, it is important that the postoperative course is equally insightful to reduce complications such as postoperative cerebrospinal fluid (CSF) leak and meningitis. Despite its critical importance, a standardized regimen for the management of patients after endoscopic skull base surgery is unavailable, and evidence for “optimal postoperative care” is lacking in the current literature. This article reviews the described methods and evidence on the postoperative management of patients after endoscopic skull base reconstruction.

Intraoperative considerations

It should be noted that a smoother postoperative recovery with less crusting and fewer issues can be encouraged by certain intraoperative maneuvers. The primary goal of skull base reconstruction is to reestablish a barrier between the sinonasal cavities and the central nervous system. However, a nearly important secondary goal is to use mucosal preservation techniques, similar to the management of inflammatory sinus disease, that maintain ostial patency and prevent scar formation. Meticulous attention to the native sinonasal anatomy preserve function and translate to improved quality of life (QOL) as patients return to their baseline nasal function more quickly. Mucosal stripping is avoided except in areas immediately surrounding the skull base defect to allow the skull base reconstruction to directly adhere to the bony skull base. It is important to medialize the middle turbinates at the end of the case to prevent middle meatal obstruction, and minimizing repetitive trauma to the middle turbinate decreases the risk of scarring.

If a nasoseptal flap (NSF) is harvested and not used as a rotational flap, it should be repositioned to the septal cartilage and bone to decrease the amount of postoperative crusting. When the mucosa is used as a rotational flap several techniques have been described to remucosalize the exposed septum. The mucosa from a resected middle turbinate can be removed and used, or mucosa from the contralateral septum can be folded over. However, in most pituitary tumor cases, an intraoperative CSF leak is not expected but may be encountered. In these cases, a “rescue” flap can be raised, which consists of partially harvesting the most superior and posterior aspect of the flap to protect its pedicle and provide access to the sphenoid face during the transsphenoidal approach. The rescue flap can be harvested fully if the resultant defect is larger than expected or if an unexpected CSF leak is encountered. Minimizing exposed bone and cartilage can reduce greatly the extent of crusting experienced postoperatively.

General postoperative course and care after endoscopic skull base surgery

Postoperatively, most patients are admitted to a neurologic nursing floor. Patients with large skull base defects who require a flap are admitted to a monitored unit (in our practice we use a neurologic step down unit or neurologic intensive care unit) for closer monitoring for at least 1 night. A face tent with mist humidification can provide the patient with comfort. Nasal cannulas are strictly avoided to reduce drying of the nasal mucosa and to prevent the theoretic possibility that applied nasal airflow may cause pneumocephalus. The patient’s head is kept elevated at 30°, and systolic blood pressure is tightly regulated to be less than 140 mm Hg, if tolerated. On the first postoperative day, the patient is started on nasal sprays (2 sprays of 0.9% saline on each side at least 4 times daily) and antibiotic ointment applied to the nose several times a day to maintain a moist nasal environment and minimize crusting. A bladder catheter is left in place overnight and removed the following day to permit ambulation (removed immediately postoperatively if no leak). The patient should avoid maneuvers that place undue pressure on the reconstruction. CSF leak precautions are reinforced to the patient (avoid bearing down, avoid nose blowing, avoid drinking from a straw, and sneeze with mouth open) and a soft bowel regimen is instituted for a period of 4 to 6 weeks. At our institution, the otolaryngology team largely dictates when the patient can resume normal activities in the postoperative period.

The schedule for follow-up nasal debridement in endoscopic skull base surgery is lacking and most authors use a schedule based on data from studies in endoscopic sinus surgery. Long-term follow-up is dictated in our practices by disease pathology. Early after surgery, we believe that skull base patients should be seen frequently and endoscopic debridement performed at regular intervals, and increased as needed. This is important to ensure proper healing and to evaluate for complications such as infection and CSF leak. These visits are also useful to outline next steps in management (eg, starting adjuvant radiation therapy, when to return to work, how long to continue CSF leak precautions) and allow us to comfort and educate the patient and their family through the next phase of their recovery.

Patients are seen for their first debridement about 7 days after surgery. During the initial debridement, nasal crusting is carefully removed from the anterior portion of the nasal cavity. In patients who had no evidence of intraoperative CSF leak or small skull base defect with a low-flow leak, the packing directly overlying the reconstruction can also be gently removed at this initial visit. Patients with large skull base reconstruction do not undergo debridement meticulously in the office initially and care is taken to avoid disturbing the mucosal edges.

Saline irrigations can be instated shortly after surgery (approximately 1–2 weeks), once the initial phase of flap healing has occurred to facilitate more aggressive cleansing of nasal crusting and mucus. At the second postoperative visit, usually 3 to 4 weeks after surgery, the patient undergoes a more complete debridement where the remainder of any crusting is diligently removed. At this time, the entire flap should be visualized and seen to be grossly incorporated into the surrounding mucosa. The patient should continue saline irrigations twice daily, particularly if there is still crusting in the nasal cavity. Additional follow-up visits may be required in cases with persistent crusting. We recommend following the patient endoscopically until the health of their nasal cavity (minimal or no crusting, nonedematous well-healed mucosa, no CSF leak) is clearly established. Once the sinonasal cavity is well-healed ( Fig. 1 ), future follow-up visits are guided by the surveillance required for the disease process being managed, which may include interval imaging studies.

( A ) Postoperative endoscopy showing healthy sinonasal cavity 3 months postoperative. ( B ) Close up of well-incorporated margins and pedicle ( arrow ) of a pedicled nasoseptal flap.

Early postoperative care strategies depending on cerebrospinal fluid leak type and reconstruction

The primary goals after skull base surgery are to return the patient to normal functioning as soon as possible and to ensure that the wound is well-healed. The type of skull base reconstruction and the presence and type of CSF leak (low flow or high flow) encountered largely dictate early postoperative management strategies. High-flow CSF leaks, as defined by Patel and colleagues, are an instance when there is violation of a cistern or ventricle. In general, a multilayered approach for skull base reconstruction larger than 3-cm reduces the risk of exposed dura, CSF leak, and meningitis, but for small defects less than 1 cm without a CSF leak, the reconstruction can use a single layer or no graft at all.

Postoperative care when there is no cerebrospinal fluid leak

There are several options available for reconstructing a skull base defect when there is not an intraoperative CSF leak. This type of closure is done to promote remucosalization of the sellar face and sphenoid sinus cavity and does not have to include multiple layers or extensive packing. The options include, but are not limited to, a free mucosal graft, which can be obtained from a resected middle turbinate or cadaveric acellular tissue (eg, Alloderm, Lifecell, Inc, Branchburg, NJ) followed by Surgicel (Ethicon, New Brunswick, NJ).

We most often use an epidural inlay DuraMatrix graft (Stryker, Kalamazoo, MI) followed by a tissue sealant (Tisseal [Baxter, Deerfield, IL] or Duraseal [Medtronic, Minneapolis, MN]) that is applied around the edges of the graft. This is then followed by placement of a dissolvable hemostatic packing (eg, Surgicel Fibrillar, Ethicon) to further seal the edges of the defect, cover the defect, and provide hemostasis. Some authors have advocated that tissue sealant may be redundant and an unnecessary expense. When no graft is chosen as the method of closure, a small amount of hemostatic dissolvable packing is placed within the sphenoid cavity. This is the simplest form of skull base patient to manage postoperatively as the care is similar to that for routine sinus surgery: no nose blowing, heavy lifting, or straining for 1 week, and the first postoperative visit is at 1 week. Saline irrigations are started immediately after surgery.

Postoperative care when there is low-flow cerebrospinal fluid leak

A low-flow leak is considered to be any leak that does not involve violation of a cistern or ventricle. The closure in this setting is not dissimilar to the type of closure used in repairing a CSF leak for an encephalocele or iatrogenic defect created after a sinus surgery misadventure. Typically, this includes placement of an underlay graft followed by an overlay graft supported by nasal packing. Options for the underlay graft, which is typically placed in the epidural space, include bone, cartilage, or dural substitutes (such as DuraMatrix). A free mucosal graft, which can be obtained from a resected middle turbinate, the septum, the inferior turbinate, or the nasal floor, are good choices for an overlay graft. The use of autologous abdominal fat and cadaveric acellular tissue (eg, Alloderm, Lifecell, Inc) have also been described for anterior and middle cranial fossa skull base defects. An NSF can also be used.

Tissue sealant (eg, Tisseal or Duraseal) can be applied around the edges of the graft followed by a dissolvable hemostatic packing (eg, Surgicel Fibrillar, Ethicon) to further seal the edges of the defect and hold it against the exposed bone. Some authors advocate placing the Surgicel Fibrillar before the tissue sealant to promote an inflammatory response and encourage scaring of the graft to the underlying bone. To further bolster the reconstruction against the bone, we like to place absorbable packing, such as Nasopore (4- or 8-cm, Polyganics, Groningen, The Netherlands) followed by a nonabsorbable packing (eg, Merocel, Medtronic). If feasible, we allow adequate nasal airway beneath the packing for patient comfort postoperatively. The nonabsorbable packing is typically removed at approximately 5 days postoperatively. The patient is started on frequent saline nasal sprays and antibiotic ointment immediately postoperatively while in hospital and is seen in follow-up at about 1 week for debridement. At that time, saline irrigations are usually instituted as well to further cleanse the nasal cavity more aggressively. These are recommended at least until all crusting resolves and the nose is healthy.