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Pierre-Olivier Champagne, Georgios A. Zenonos, Eric W. Wang, Carl H. Snyderman, and Paul A. Gardner

OBJECTIVE

The endoscopic endonasal approach (EEA) to the lower clivus and craniovertebral junction (CVJ) has been traditionally performed via resection of the nasopharyngeal soft tissues. Alternatively, an inferiorly based rhinopharyngeal (RP) flap (RPF) can be dissected to help reconstruct the postoperative defect and separate it from the oropharynx. To date, there is no evidence regarding the viability and potential clinical impact of the RPF. The aim of this study was to assess RPF viability and its impact on clinical outcome.

METHODS

A retrospective cohort of 60 patients who underwent EEA to the lower clivus and CVJ was studied. The RPF was used in 30 patients (RPF group), and the nasopharyngeal soft tissues were resected in 30 patients (control group).

RESULTS

Chordoma was the most common surgical indication in both groups (47% in the RPF group vs 63% in the control group, p = 0.313), followed by odontoid pannus (20% in the RPF group vs 10%, p = 0.313). The two groups did not significantly differ in terms of extent of tumor (p = 0.271), intraoperative CSF leak (p = 0.438), and skull base reconstruction techniques other than the RPF (nasoseptal flap, p = 0.301; fascia lata, p = 0.791; inlay graft, p = 0.793; and prophylactic lumbar drain, p = 0.781). Postoperative soft-tissue enhancement covering the lower clivus and CVJ observed on MRI was significantly higher in the RPF group (100% vs 26%, p < 0.001). The RPF group had a significantly lower rate of nasoseptal flap necrosis (3% vs 20%, p = 0.044) and surgical site infection (3% vs 27%, p = 0.026) while having similar rates of postoperative CSF leakage (17% in the RPF group vs 20%, p = 0.739) and meningitis (7% in the RPF group vs 17%, p = 0.424). Oropharyngeal bacterial flora dominated the infections in the control group but not those in the RPF group, suggesting that the RPF acted as a barrier between the nasopharynx and oropharynx.

CONCLUSIONS

The RPF provides viable vascularized tissue coverage to the lower clivus and CVJ. Its use was associated with decreased rates of nasoseptal flap necrosis and local infection, likely due to separation from the oropharynx.

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David T. Fernandes Cabral, Georgios A. Zenonos, Juan C. Fernandez-Miranda, Eric W. Wang, and Paul A. Gardner

OBJECTIVE

Iatrogenic tumor seeding after open surgery for chordoma has been well described in the literature. The incidence and particularities related to endoscopic endonasal surgery (EES) have not been defined.

METHODS

The authors retrospectively reviewed their experience with EES for clival chordoma, focusing on cases with iatrogenic seeding. The clinical, radiographic, pathological, and molecular characterization data were reviewed.

RESULTS

Among 173 EESs performed for clival chordomas at the authors’ institution between April 2003 and May 2016, 2 cases complicated by iatrogenic seeding (incidence 1.15%) were identified. The first case was a 10-year-old boy, who presented 21 months after an EES for a multiply recurrent clival chordoma with a recurrence along the left inferior turbinate, distinct from a right petrous apex recurrence. Both appeared as a T2-hypertintense, T1-isointense, and heterogeneously enhancing lesion on MRI. Resection of the inferior turbinate recurrence and debulking of the petrous recurrence were both performed via a purely endoscopic endonasal approach. Unfortunately, the child died 2 years later due progression of disease at the primary site, but with no sign of progression at the seeded site. The second patient was a 79-year-old man with an MRI-incompatible pacemaker who presented 19 months after EES for his clival chordoma with a mass involving the floor of the left nasal cavity that was causing an oro-antral fistula. On CT imaging, this appeared as a homogeneously contrast-enhancing mass eroding the hard palate inferiorly, the nasal septum superiorly, and the nasal process of the maxilla, with extension into the subcutaneous tissue. This was also treated endoscopically (combined transnasal-transoral approach) with resection of the mass, and repair of the fistula by using a palatal and left lateral wall rotational flap. Adjuvant hypofractionated stereotactic CyberKnife radiotherapy was administered using 35 Gy in 5 fractions. No recurrence was appreciated endoscopically or on imaging at the patient’s last follow-up, 12 months after this last procedure. In both cases, pathological investigation of the original tumors revealed a fairly aggressive biology with 1p36 deletions, and high Ki-67 levels (10%–15%, and > 20%, respectively). The procedures were performed by a team of right-handed surgeons (otolaryngology and neurosurgery), using a 4-handed technique (in which the endoscope and suction are typically passed through the right nostril, and other instruments are passed through the left nostril without visualization).

CONCLUSIONS

Although uncommon, iatrogenic seeding occurs during EES for clival chordomas, probably because of decreased visualization during tumor removal combined with mucosal trauma and exposure of subepithelial elements (either inadvertently or because of mucosal flaps). In addition, tumors with more aggressive biology (1p36 deletions, elevated Ki-67, or both) are probably at a higher risk and require increased vigilance on surveillance imaging and endoscopy. Further prospective studies are warranted to evaluate the authors’ proposed strategies for decreasing the incidence of iatrogenic seeding after EES for chordomas.

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Wei-Hsin Wang, Stefan Lieber, Ming-Ying Lan, Eric W. Wang, Juan C. Fernandez-Miranda, Carl H. Snyderman, and Paul A. Gardner

OBJECTIVE

Injury to the internal carotid artery (ICA) is the most critical complication of endoscopic endonasal skull base surgery. Packing with a crushed muscle graft at the injury site has been an effective management technique to control bleeding without ICA sacrifice. Obtaining the muscle graft has typically required access to another surgical site, however. To address this concern, the authors investigated the application of an endonasally harvested longus capitis muscle patch for the management of ICA injury.

METHODS

One colored silicone-injected anatomical specimen was dissected to replicate the surgical access to the nasopharynx and the stepwise dissection of the longus capitis muscle in the nasopharynx. Two representative cases were selected to illustrate the application of the longus capitis muscle patch and the relevance of clinical considerations.

RESULTS

A suitable muscle graft from the longus capitis muscle could be easily and quickly harvested during endoscopic endonasal skull base surgery. In the illustrative cases, the longus capitis muscle patch was successfully used for secondary prevention of pseudoaneurysm formation following primary bleeding control on the site of ICA injury.

CONCLUSIONS

Nasopharyngeal harvest of a longus capitis muscle graft is a safe and practical method to manage ICA injury during endoscopic endonasal surgery.

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Salomon Cohen-Cohen, Paul A. Gardner, Joao T. Alves-Belo, Huy Q. Truong, Carl H. Snyderman, Eric W. Wang, and Juan C. Fernandez-Miranda

OBJECTIVE

Pituitary adenomas often invade the medial wall of the cavernous sinus (CS), but this structure is generally not surgically removed because of the risk of vascular and cranial nerve injury. The purpose of this study was to report the surgical outcomes in a large series of cases of invasive pituitary adenoma in which the medial wall of the CS was selectively removed following an anatomically based, stepwise surgical technique.

METHODS

The authors’ institutional database was reviewed to identify cases of pituitary adenoma with isolated invasion of the medial wall, based on an intraoperative evaluation, in which patients underwent an endoscopic endonasal approach with selective resection of the medial wall of the CS. Cases with CS invasion beyond the medial wall were excluded. Patient complications, resection, and remission rates were assessed.

RESULTS

Fifty patients were eligible for this study, 15 (30%) with nonfunctional adenomas and 35 (70%) with functional adenomas, including 16 growth hormone–, 10 prolactin-, and 9 adrenocorticotropic hormone (ACTH)–secreting tumors. The average tumor size was 2.3 cm for nonfunctional and 1.3 cm for functional adenomas. Radiographically, 11 cases (22%) were Knosp grade 1, 23 (46%) Knosp grade 2, and 16 (32%) Knosp grade 3. Complete tumor resection, based on intraoperative impression and postoperative MRI, was achieved in all cases. The mean follow-up was 30 months (range 4–64 months) for patients with functional adenomas and 16 months (range 4–30 months) for those with nonfunctional adenomas. At last follow-up, complete biochemical remission (using current criteria) without adjuvant treatment was seen in 34 cases (97%) of functional adenoma. No imaging recurrences were seen in patients who had nonfunctional adenomas. A total of 57 medial walls were removed in 50 patients. Medial wall invasion was histologically confirmed in 93% of nonfunctional adenomas and 83% of functional adenomas. There were no deaths or internal carotid artery injuries, and the average blood loss was 378 ml. Four patients (8%) developed a new, transient cranial nerve palsy, and 2 of these patients required reoperation for blood clot evacuation and fat graft removal. There were no permanent cranial nerve palsies.

CONCLUSIONS

The medial wall of the CS can be removed safely and effectively, with minimal morbidity and excellent resection and remission rates. Further follow-up is needed to determine the long-term results of this anatomically based technique, which should only be performed by very experienced endonasal skull base teams.

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Nathan T. Zwagerman, Eric W. Wang, Samuel S. Shin, Yue-Fang Chang, Juan C. Fernandez-Miranda, Carl H. Snyderman, and Paul A. Gardner

OBJECTIVE

Based on a null hypothesis that the use of short-term lumbar drainage (LD) after endoscopic endonasal surgery (EES) for intradural pathology does not prevent postoperative CSF leaks, a trial was conducted to assess the effect of postoperative LD on postoperative CSF leak following standard reconstruction.

METHODS

A prospective, randomized controlled trial of lumbar drain placement after endoscopic endonasal skull base surgery was performed from February 2011 to March 2015. All patients had 3-month follow-up data. Surgeons were blinded to which patients would or would not receive the drain until after closure was completed. An a priori power analysis calculation assuming 80% of power, 5% postoperative CSF leak rate in the no-LD group, and 16% in the LD group determined a planned sample size of 186 patients. A routine data and safety check was performed with every 50 patients being recruited to ensure the efficacy of randomization and safety. These interim tests were run by a statistician who was not blinded to the arms they were evaluating. This study accrued 230 consecutive adult patients with skull base pathology who were eligible for endoscopic endonasal resection. Inclusion criteria (high-flow leak) were dural defect greater than 1 cm2 (mandatory), extensive arachnoid dissection, and/or dissection into a ventricle or cistern. Sixty patients were excluded because they did not meet the inclusion criteria. One hundred seventy patients were randomized to either receive or not receive a lumbar drain.

RESULTS

One hundred seventy patients were randomized, with a mean age of 51.6 years (range 19–86 years) and 38% were male. The mean BMI for the entire cohort was 28.1 kg/m2. The experimental cohort with postoperative LD had an 8.2% rate of CSF leak compared to a 21.2% rate in the control group (odds ratio 3.0, 95% confidence interval 1.2–7.6, p = 0.017). In 106 patients in whom defect size was measured intraoperatively, a larger defect was associated with postoperative CSF leak (6.2 vs 2.9 cm2, p = 0.03). No significant difference was identified in BMI between those with (mean 28.4 ± 4.3 kg/m2) and without (mean 28.1 ± 5.6 kg/m2) postoperative CSF leak (p = 0.79). Furthermore, when patients were grouped based on BMI < 25, 25–29.9, and > 30 kg/m2, no difference was noted in the rates of CSF fistula (p = 0.97).

CONCLUSIONS

Among patients undergoing intradural EES judged to be at high risk for CSF leak as defined by the study’s inclusion criteria, perioperative LD used in the context of vascularized nasoseptal flap closure significantly reduced the rate of postoperative CSF leaks.

Clinical trial registration no.: NCT03163134 (clinicaltrials.gov).

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Nathan T. Zwagerman, Matthew J. Tormenti, Zachary J. Tempel, Eric W. Wang, Carl H. Snyderman, Juan C. Fernandez-Miranda, and Paul A. Gardner

OBJECTIVE

Treatment of odontoid disease from a ventral corridor has consisted of a transoral approach. More recently, the endoscopic endonasal approach (EEA) has been used to access odontoid pathology.

METHODS

A retrospective review was conducted of patients who underwent an EEA for odontoid pathology from 2004 to 2013. During our analysis, the mean follow-up duration was 42.6 months (range 1–80 months). Patient outcomes, complications, and postoperative swallowing function were assessed either by clinic visit or phone contact.

RESULTS

Thirty-four patients underwent an EEA for symptomatic odontoid pathology. The most common pathology treated was basilar invagination (n = 17). Other pathologies included odontoid fractures, os odontoideum, and metastatic carcinoma. The mean patient age was 71.5 years. Thirty-one patients underwent a posterior fusion. All 34 patients experienced stability or improvement in symptoms and all had successful radiographic decompression. The overall complication rate was 76%. Nearly all of these complications were transient (86%) and the overall complication rate excluding mild transient dysphagia was only 44%. Twenty-one patients (62%) suffered from transient postoperative dysphagia: 15 cases were mild, transient subjective dysphagia (6 of whom had documented preoperative dysphagia), whereas 6 other patients required tube feedings for decreased oral intake, malnutrition, and dysphagia in the perioperative setting (5 of these patients had documented preoperative dysphagia). Sixteen patients had documented preoperative dysphagia and 6 of these had lower cranial nerve dysfunction. Postoperatively, 6 (37.5%) of 16 patients with preoperative dysphagia and 4 (67%) of 6 with lower cranial nerve dysfunction had significant dysphagia/respiratory complications. Eighteen patients had no documented preoperative dysphagia and only 2 had significant postoperative dysphagia/respiratory complications (11%). The rates of these complications in patients without preoperative dysphagia were lower than in those with any preoperative dysphagia (p = 0.07) and especially those with preexisting lower cranial neuropathies (p = 0.007). Dysphagia was also significantly more common in patients who underwent occipitocervical fixation (19/26, 73%) than in patients who underwent cervical fusion alone or no fusion (2/8, 25%; p = 0.02). All patients with perioperative dysphagia had improved at follow-up and all patients were tolerating oral diets. No patient suffered from velopalatal insufficiency. Two patients had intraoperative CSF leaks. One of these patients underwent a negative exploratory surgery for a questionable postoperative CSF leak. One patient developed infection in the resection bed requiring debridement and antibiotics. One patient died 8 days following surgery from an unknown cause. The 90-day perioperative mortality rate was 2.9%.

CONCLUSIONS

A completely EEA can be performed for compressive odontoid disease in all cases of neoplastic, degenerative, or invaginative atlantoaxial disease with satisfactory outcomes and low morbidity. Transient perioperative dysphagia and respiratory complications are common, usually as an exacerbation and reflection of underlying disease or occipitocervical fusion rather than the EEA, emphasizing the importance of avoiding transoral surgery.

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Juan C. Fernandez-Miranda, Nathan T. Zwagerman, Kumar Abhinav, Stefan Lieber, Eric W. Wang, Carl H. Snyderman, and Paul A. Gardner

OBJECTIVE

Tumors with cavernous sinus (CS) invasion represent a neurosurgical challenge. Increasing application of the endoscopic endonasal approach (EEA) requires a thorough understanding of the CS anatomy from an endonasal perspective. In this study, the authors aimed to develop a surgical anatomy–based classification of the CS and establish its utility for preoperative surgical planning and intraoperative guidance in adenoma surgery.

METHODS

Twenty-five colored silicon–injected human head specimens were used for endonasal and transcranial dissections of the CS. Pre- and postoperative MRI studies of 98 patients with pituitary adenoma with intraoperatively confirmed CS invasion were analyzed.

RESULTS

Four CS compartments are described based on their spatial relationship with the cavernous ICA: superior, posterior, inferior, and lateral. Each compartment has distinct boundaries and dural and neurovascular relationships: the superior compartment relates to the interclinoidal ligament and oculomotor nerve, the posterior compartment bears the gulfar segment of the abducens nerve and inferior hypophyseal artery, the inferior compartment contains the sympathetic nerve and distal cavernous abducens nerve, and the lateral compartment includes all cavernous cranial nerves and the inferolateral arterial trunk. Twenty-nine patients had a single compartment invaded, and 69 had multiple compartments involved. The most commonly invaded compartment was the superior (79 patients), followed by the posterior (n = 64), inferior (n = 45), and lateral (n = 23) compartments. Residual tumor rates by compartment were 79% in lateral, 17% in posterior, 14% in superior, and 11% in inferior.

CONCLUSIONS

The anatomy-based classification presented here complements current imaging-based classifications and may help to identify involved compartments both preoperatively and intraoperatively.

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Maria Koutourousiou, Paul A. Gardner, Juan C. Fernandez-Miranda, Elizabeth C. Tyler-Kabara, Eric W. Wang, and Carl H. Snyderman

Object

The proximity of craniopharyngiomas to vital neurovascular structures and their high recurrence rates make them one of the most challenging and controversial management dilemmas in neurosurgery. Endoscopic endonasal surgery (EES) has recently been introduced as a treatment option for both pediatric and adult craniopharyngiomas. The object of the present study was to present the results of EES and analyze outcome in both the pediatric and the adult age groups.

Methods

The authors retrospectively reviewed the records of patients with craniopharyngioma who had undergone EES in the period from June 1999 to April 2011.

Results

Sixty-four patients, 47 adults and 17 children, were eligible for this study. Forty-seven patients had presented with primary craniopharyngiomas and 17 with recurrent tumors. The mean age in the adult group was 51 years (range 28–82 years); in the pediatric group, 9 years (range 4–18 years). Overall, the gross-total resection rate was 37.5% (24 patients); near-total resection (> 95% of tumor removed) was 34.4% (22 patients); subtotal resection (≥ 80% of tumor removed) 21.9% (14 patients); and partial resection (< 80% of tumor removed) 6.2% (4 patients). In 9 patients, EES had been combined with radiation therapy (with radiosurgery in 6 cases) as the initial treatment. Among the 40 patients (62.5%) who had presented with pituitary insufficiency, pituitary function remained unchanged in 19 (47.5%), improved or normalized in 8 (20%), and worsened in 13 (32.5%). In the 24 patients who had presented with normal pituitary function, new pituitary deficit occurred in 14 (58.3%). Nineteen patients (29.7%) suffered from diabetes insipidus at presentation, and the condition developed in 21 patients (46.7%) after treatment. Forty-four patients (68.8%) had presented with impaired vision. In 38 (86.4%) of them, vision improved or even normalized after surgery; in 5, it remained unchanged; and in 1, it temporarily worsened. One patient without preoperative visual problems showed temporary visual deterioration after treatment. Permanent visual deterioration occurred in no one after surgery. The mean follow-up was 38 months (range 1–135 months). Tumor recurrence after EES was discovered in 22 patients (34.4%) and was treated with repeat surgery (6 patients), radiosurgery (1 patient), combined repeat surgery and radiation therapy (8 patients), interferon (1 patient), or observation (6 patients). Surgical complications included 15 cases (23.4%) with CSF leakage that was treated with surgical reexploration (13 patients) and/or lumbar drain placement (9 patients). This leak rate was decreased to 10.6% in recent years after the introduction of the vascularized nasoseptal flap. Five cases (7.8%) of meningitis were found and treated with antibiotics without further complications. Postoperative hydrocephalus occurred in 7 patients (12.7%) and was treated with ventriculoperitoneal shunt placement. Five patients experienced transient cranial nerve palsies. There was no operative mortality.

Conclusions

With the goal of gross-total or maximum possible safe resection, EES can be used for the treatment of every craniopharyngioma, regardless of its location, size, and extension (excluding purely intraventricular tumors), and can provide acceptable results comparable to those for traditional craniotomies. Endoscopic endonasal surgery is not limited to adults and actually shows higher resection rates in the pediatric population.

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Joseph D. Chabot, Chirag R. Patel, Marion A. Hughes, Eric W. Wang, Carl H. Snyderman, Paul A. Gardner, and Juan C. Fernandez-Miranda

OBJECTIVE

The vascularized nasoseptal flap (NSF) has become the workhorse for skull base reconstruction during endoscopic endonasal surgery (EES) of the ventral skull base. Although infrequently reported, as with any vascularized flap the NSF may undergo ischemic necrosis and become a nidus for infection. The University of Pittsburgh Medical Center’s experience with NSF was reviewed to determine the incidence of necrotic NSF in patients following EES and describe the clinical presentation, imaging characteristics, and risk factors associated with this complication.

METHODS

The electronic medical records of 1285 consecutive patients who underwent EES at the University of Pittsburgh Medical Center between January 2010 and December 2014 were retrospectively reviewed. From this first group, a list of all patients in whom NSF was used for reconstruction was generated and further refined to determine if the patient returned to the operating room and the cause of this reexploration. Patients were included in the final analysis if they underwent endoscopic reexploration for suspected CSF leak or meningitis. Those patients who returned to the operating room for staged surgery or hematoma were excluded. Two neurosurgeons and a neuroradiologist, who were blinded to each other’s results, assessed the MRI characteristics of the included patients.

RESULTS

In total, 601 patients underwent NSF reconstruction during the study period, and 49 patients met the criteria for inclusion in the final analysis. On endoscopic exploration, 8 patients had a necrotic, nonviable NSF, while 41 patients had a viable NSF with a CSF leak. The group of patients with a necrotic, nonviable NSF was then compared with the group with viable NSF. All 8 patients with a necrotic NSF had clinical and laboratory evidence indicative of meningitis compared with 9 of 41 patients with a viable NSF (p < 0.001). Four patients with necrotic flaps developed epidural empyema compared with 2 of 41 patients in the viable NSF group (p = 0.02). The lack of NSF enhancement on MR (p < 0.001), prior surgery (p = 0.043), and the use of a fat graft (p = 0.004) were associated with necrotic NSF.

CONCLUSIONS

The signs of meningitis after EES in the absence of a clear CSF leak with the lack of NSF enhancement on MRI should raise the suspicion of necrotic NSF. These patients should undergo prompt exploration and debridement of nonviable tissue with revision of skull base reconstruction.

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Pierre-Olivier Champagne, Michael M. McDowell, Eric W. Wang, Carl H. Snyderman, Georgios A. Zenonos, and Paul A. Gardner

OBJECTIVE

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, endoscopic endonasal surgery (EES) is feared to be a high-risk procedure for the transmission of coronavirus disease 2019 (COVID-19). Nonetheless, data are lacking regarding the management of EES during the pandemic. The object of this study was to understand current worldwide practices pertaining to EES for skull base/pituitary tumors during the SARS-CoV-2 pandemic and provide a basis for the formulation of guidelines.

METHODS

The authors conducted a web-based survey of skull base surgeons worldwide. Different practices by geographic region and COVID-19 prevalence were analyzed.

RESULTS

One hundred thirty-five unique responses were collected. Regarding the use of personal protective equipment (PPE), North America reported using more powered air-purifying respirators (PAPRs), and Asia and Europe reported using more standard precautions. North America and Europe resorted more to reverse transcriptase–polymerase chain reaction (RT-PCR) for screening asymptomatic patients. High-prevalence countries showed a higher use of PAPRs. The medium-prevalence group reported lower RT-PCR testing for symptomatic cases, and the high-prevalence group used it significantly more in asymptomatic cases.

Nineteen respondents reported transmission of COVID-19 to healthcare personnel during EES, with a higher rate of transmission among countries classified as having a medium prevalence of COVID-19. These specific respondents (medium prevalence) also reported a lower use of airborne PPE. In the cases of healthcare transmission, the patient was reportedly asymptomatic 32% of the time.

CONCLUSIONS

This survey gives an overview of EES practices during the SARS-CoV-2 pandemic. Intensified preoperative screening, even in asymptomatic patients, RT-PCR for all symptomatic cases, and an increased use of airborne PPE is associated with decreased reports of COVID-19 transmission during EES.