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.

Endoscopic endonasal resection of sinonasal teratocarcinosarcoma with intracranial breakthrough: illustrative case

BACKGROUND

Teratocarcinosarcoma traversing the anterior skull base is rarely reported in literature. The heterogenous and invasive features of the tumor pose challenges for surgical planning. With technological advancements, the endoscopic endonasal approach (EEA) has been emerging as a workhorse of anterior skull base lesions. To date, no case has been reported of EEA totally removing teratocarcinosarcomas with intracranial extensions.

OBSERVATIONS

The authors provided an illustrative case of a 50-year-old otherwise healthy man who presented with left-sided epistaxis for a year. Imaging studies revealed a 31 × 60-mm communicating lesion of the anterior skull base. Gross total resection via EEA was achieved, and multilayered skull base reconstruction was performed.

LESSONS

The endoscopic approach may be safe and effective for resection of extensive teratocarcinosarcoma of the anterior skull base. To minimize the risk of postoperative cerebrospinal fluid leaks, multilayered skull base reconstruction and placement of lumbar drainage are vitally important.

Impact of tumor characteristics and pre- and postoperative hormone levels on hormonal remission following endoscopic transsphenoidal surgery in patients with acromegaly

OBJECTIVE

Acromegaly is a disease of acral enlargement and elevated serum levels of insulin-like growth factor-1 (IGF-1) and growth hormone (GH), usually caused by a pituitary adenoma. A lack of consensus on factors that reliably predict outcomes in acromegalic patients following endoscopic endonasal transsphenoidal surgery (EETS) warrants additional investigation.

METHODS

The authors identified 52 patients with acromegaly who underwent an endoscopic endonasal approach (EEA) for resection of a GH-secreting pituitary adenoma. Preoperative and postoperative tumor and endocrinological characteristics such as tumor size, invasiveness, and GH/IGF-1 levels were evaluated as potential indicators of postoperative hormonal remission. Endocrinological remission was defined as postoperative IGF-1 levels at or below the age- and sex-normalized values.

RESULTS

The 52 patients had a mean age of 50.7 ± 13.4 years and a mean follow-up duration of 24.4 ± 19.1 months. Ten patients (19%) had microadenomas and 42 (81%) had macroadenomas. Five patients (9.6%) had giant adenomas. Forty-four tumors (85%) had extrasellar extension, with 40 (77%) exhibiting infrasellar invasion, 18 (35%) extending above the sella, and 7 (13%) invading the cavernous sinuses. Thirty-six patients (69%) underwent gross-total resection (GTR; mean maximal tumor diameter 1.47 cm), and 16 (31%) underwent subtotal resection (STR; mean maximal tumor diameter 2.74 cm). Invasive tumors were significantly larger, and Knosp scores were negatively correlated with GTR. Thirty-eight patients (73%) achieved hormonal remission after EEA resection alone, which increased to 87% with adjunctive medical therapy. Ninety percent of patients with microadenomas and 86% of patients with macroadenomas achieved hormonal remission. Preoperative IGF-1 and postoperative day 1 (POD1) GH levels were inversely correlated with hormonal remission. Postoperative CSF leakage occurred in 2 patients (4%), and none experienced vision loss, death, or injury to internal carotid arteries or cranial nerves.

CONCLUSIONS

Endoscopic transsphenoidal resection of GH-secreting pituitary adenomas is a safe and highly effective treatment for achieving hormonal remission and tumor control in up to 87% of patients with acromegaly when combined with postoperative medical therapy. Patients with lower preoperative IGF-1 and POD1 GH levels, with less invasive pituitary adenomas, and who undergo GTR are more likely to achieve postoperative biochemical remission.

Machine learning-based prediction of outcomes of the endoscopic endonasal approach in Cushing disease: is the future coming?

OBJECTIVE

Machine learning (ML) is an innovative method to analyze large and complex data sets. The aim of this study was to evaluate the use of ML to identify predictors of early postsurgical and long-term outcomes in patients treated for Cushing disease (CD).

METHODS

All consecutive patients in our center who underwent surgery for CD through the endoscopic endonasal approach were retrospectively reviewed. Study endpoints were gross-tumor removal (GTR), postsurgical remission, and long-term control of disease. Several demographic, radiological, and histological factors were assessed as potential predictors. For ML-based modeling, data were randomly divided into 2 sets with an 80% to 20% ratio for bootstrapped training and testing, respectively. Several algorithms were tested and tuned for the area under the curve (AUC).

RESULTS

The study included 151 patients. GTR was achieved in 137 patients (91%), and postsurgical hypersecretion remission was achieved in 133 patients (88%). At last follow-up, 116 patients (77%) were still in remission after surgery and in 21 patients (14%), CD was controlled with complementary treatment (overall, of 131 cases, 87% were under control at follow-up). At internal validation, the endpoints were predicted with AUCs of 0.81-1.00, accuracy of 81%-100%, and Brier scores of 0.035-0.151. Tumor size and invasiveness and histological confirmation of adrenocorticotropic hormone (ACTH)-secreting cells were the main predictors for the 3 endpoints of interest.

CONCLUSIONS

ML algorithms were used to train and internally validate robust models for all the endpoints, giving accurate outcome predictions in CD cases. This analytical method seems promising for potentially improving future patient care and counseling; however, careful clinical interpretation of the results remains necessary before any clinical adoption of ML. Moreover, further studies and increased sample sizes are definitely required before the widespread adoption of ML to the study of CD.

The underestimated incidence of an orbital angioleiomyoma is possibly associated with an orbital cavernous hemangioma: illustrative case

BACKGROUND

Orbital angioleiomyoma is generally considered a rare tumor; approximately 40 cases have been reported. However, after their experience with 6 consecutive cases in their single institution during 3 years, the authors speculate that the incidence of orbital angioleiomyomas is possibly underestimated.

OBSERVATIONS

A 34-year-old female presented with progressive exophthalmos of 2 years' duration. Orbital computed tomography and magnetic resonance imaging revealed a well-circumscribed orbital tumor with partial and heterogeneous gadolinium enhancement. Technetium-99m red blood cell single-photon emission computed tomography showed positive perfusion in the late blood-pool phase, which was exactly consistent with the finding of a cavernous hemangioma. Under the impression of a cavernous hemangioma, the authors accessed the mass with an endoscopic endonasal approach and completely removed it without neurological deficit. Pathological examination revealed that the final diagnosis was an angioleiomyoma with positive immunostaining results for smooth muscle actin (SMA).

LESSONS

The incidence of orbital angioleiomyomas may not be very low, as these lesions have possibly been misdiagnosed as orbital cavernous hemangiomas because of their histological similarity. Preoperative presumption and differentiation from cavernous hemangiomas are very challenging because of the rarity of orbital angioleiomyoma and similar radiological findings. SMA immunostaining may be critical to differentiate orbital angioleiomyomas from cavernous hemangiomas.

Endoscopic transorbital and endonasal approach for trigeminal schwannomas: a retrospective multicenter analysis (KOSEN-005)

OBJECTIVE

Trigeminal schwannomas are rare neoplasms with an incidence of less than 1% that require a comprehensive surgical strategy. These tumors can occur anywhere along the path of the trigeminal nerve, capable of extending intradurally into the middle and posterior fossae, and extracranially into the orbital, pterygopalatine, and infratemporal fossa. Recent advancements in endoscopic surgery have suggested a more minimally invasive and direct route for tumors in and around Meckel's cave, including the endoscopic endonasal approach (EEA) and endoscopic transorbital superior eyelid approach (ETOA). The authors assess the feasibility and outcomes of EEA and ETOA for trigeminal schwannomas.

METHODS

A retrospective multicenter analysis was performed on 25 patients who underwent endoscopic surgical treatment for trigeminal schwannomas between September 2011 and February 2019. Thirteen patients (52%) underwent EEA and 12 (48%) had ETOA, one of whom underwent a combined approach with retrosigmoid craniotomy. The extent of resection, clinical outcome, and surgical morbidity were analyzed to evaluate the feasibility and selection of surgical approach between EEA and ETOA based on predominant location of trigeminal schwannomas.

RESULTS

According to predominant tumor location, 9 patients (36%) had middle fossa tumors (Samii type A), 8 patients (32%) had dumbbell-shaped tumors located in the middle and posterior cranial fossae (Samii type C), and another 8 patients (32%) had extracranial tumors (Samii type D). Gross-total resection (GTR, n = 12) and near-total resection (NTR, n = 7) were achieved in 19 patients (76%). The GTR/NTR rates were 81.8% for ETOA and 69.2% for EEA. The GTR/NTR rates of ETOA and EEA according to the classifications were 100% and 50% for tumors confined to the middle cranial fossa, 75% and 33% for dumbbell-shaped tumors located in the middle and posterior cranial fossae, and 50% and 100% for extracranial tumors. There were no postoperative CSF leaks. The most common preoperative symptom was trigeminal sensory dysfunction, which improved in 15 of 21 patients (71.4%). Three patients experienced new postoperative complications such as vasospasm (n = 1), wound infection (n = 1), and medial gaze palsy (n = 1).

CONCLUSIONS

ETOA provides adequate access and resectability for trigeminal schwannomas limited in the middle fossa or dumbbell-shaped tumors located in the middle and posterior fossae, as does EEA for extracranial tumors. Tumors predominantly involving the posterior fossa still remain a challenge in endoscopic surgery.

Development and clinical validation of a grading system for pituitary adenoma consistency

OBJECTIVE

Pituitary adenoma (PA) consistency, or texture, is an important intraoperative characteristic that may dictate operative dissection techniques and/or instruments used for tumor removal during endoscopic endonasal approaches (EEAs). The impact of PA consistency on surgical outcomes has yet to be elucidated.

METHODS

The authors developed an objective 5-point grading scale for PA consistency based on intraoperative characteristics, including ease of tumor debulking, manipulation, and instrument selection, ranging from cystic/hemorrhagic tumors (grade 1) to calcified tumors (grade 5). The proposed grading system was prospectively assessed in 306 consecutive patients who underwent an EEA for PAs, and who were subsequently analyzed for associations with surgical outcomes, including extent of resection (EOR) and complication profiles.

RESULTS

Institutional database review identified 306 patients who underwent intraoperative assessment of PA consistency, of which 96% were macroadenomas, 70% had suprasellar extension, and 44% had cavernous sinus invasion (CSI). There were 214 (69.9%) nonfunctional PAs and 92 functional PAs (31.1%). Distribution of scores included 15 grade 1 tumors (4.9%), 112 grade 2 tumors (36.6%), 125 grade 3 tumors (40.8%), 52 grade 4 tumors (17%), and 2 grade 5 tumors (0.7%). Compared to grade 1/2 and grade 3 PAs, grade 4/5 PAs were significantly larger (22.5 vs 26.6 vs 27.4 mm, p < 0.01), more likely to exhibit CSI (39% vs 42% vs 59%, p < 0.05), and trended toward nonfunctionality (67% vs 68% vs 82%, p = 0.086). Although there was no association between PA consistency and preoperative headaches or visual dysfunction, grade 4/5 PAs trended toward preoperative (p = 0.058) and postoperative panhypopituitarism (p = 0.066). Patients with preoperative visual dysfunction experienced greater improvement if they had a grade 1/2 PA (p < 0.05). Intraoperative CSF leaks were noted in 32% of cases and were more common with higher-consistency-grade tumors (p = 0.048), although this difference did not translate to postoperative CSF leaks. Gross-total resection (%) was more likely with lower PA consistency score as follows: grade 1/2 (60%), grade 3 (50%), grade 4/5 (44%; p = 0.045). Extracapsular techniques were almost exclusively performed in grade 4/5 PAs. Assignment of scores showed low variance and high reproducibility, with an intraclass correlation coefficient of 0.905 (95% CI 0.815-0.958), indicating excellent interrater reliability.

CONCLUSIONS

These findings demonstrate clinical validity of the proposed intraoperative grading scale with respect to PA subtype, neuroimaging features, EOR, and endocrine complications. Future studies will assess the relation of PA consistency to preoperative MRI findings to accurately predict consistency, thereby allowing the surgeon to tailor the exposure and prepare for varying resection strategies.

A modern series of subdiaphragmatic craniopharyngiomas

OBJECTIVE

The endoscopic endonasal approach has been proposed as a primary surgical strategy for select craniopharyngiomas. However, those tumors that arise from the sella have not been classified with the other craniopharyngioma subtypes in terms of surgical nuances, intraoperative findings, and postoperative outcomes. The authors describe their experience with a select subtype of craniopharyngioma arising within the sella subjacent to the diaphragma sellae and refer to these tumors as type 0.

METHODS

After obtaining IRB approval, three institutions retrospectively reviewed their data collected from 2005 to 2017. Patients eligible for inclusion in the study were those who had tumors that originated from the sella inferior to the diaphragma sellae. Demographic, clinical, radiological, surgical, and follow-up data were examined and analyzed.

RESULTS

Twenty-eight patients (average age 19.3 years, range 3-60 years) were included in this study. Sixteen patients (57%) were younger than 18 years of age. All patients had characteristic imaging features of an expanded sella. Seventy-five percent of the patients presented with some form of visual field deficit (89% had radiographic optic apparatus compression) and 39% with hypopituitarism. The average maximal tumor diameter in the axial, coronal, or sagittal plane was 3.1 cm. Gross-total resection was achieved in 82% of the patients. Twenty-one percent of patients experienced an iatrogenic complication, and there were only two cases (7%) of postoperative cerebrospinal fluid (CSF) leakage. Only two patients (7%) required the use of a nasoseptal flap as part of their original reconstruction. Pathology was uniformly the adamantinomatous subtype. Postoperative objective visual outcomes were improved in 71% of the patients with visual symptoms or visual field deficits on presentation and stable in 24%. Mean follow-up was 45.1 months (range 3-120 months) with an 18% recurrence rate at a mean of 44.4 months (range 10-84 months). One patient was lost to follow-up. Thirty-six percent of patients received postoperative radiation to treat recurrence or residual tumor. Endocrine data are also presented.

CONCLUSIONS

Craniopharyngiomas that originate within the sella below the diaphragma sellae are a select subtype characterized by 1) an enlarged sella, 2) an intact diaphragma sellae at surgery, and 3) an adamantinomatous pathology. These tumors can be treated transnasally without the absolute need for neurovascular flap reconstruction, as there is a low risk of CSF leakage.

Decision-making algorithm for minimally invasive approaches to anterior skull base meningiomas

OBJECTIVE Anterior skull base meningiomas are benign lesions that cause neurological symptoms through mass effect on adjacent neurovascular structures. While traditional transcranial approaches have proven to be effective at removing these tumors, minimally invasive approaches that involve using an endoscope offer the possibility of reducing brain and nerve retraction, minimizing incision size, and speeding patient recovery; however, appropriate case selection and results in large series are lacking. METHODS The authors developed an algorithm for selecting a supraorbital keyhole minicraniotomy (SKM) for olfactory groove meningiomas or an expanded endoscopic endonasal approach (EEA) for tuberculum sella (TS) or planum sphenoidale (PS) meningiomas based on the presence or absence of olfaction and the anatomical extent of the tumor. Where neither approach is appropriate, a standard transcranial approach is utilized. The authors describe rates of gross-total resection (GTR), olfactory outcomes, and visual outcomes, as well as complications, for 7 subgroups of patients. Exceptions to the algorithm are also discussed. RESULTS The series of 57 patients harbored 57 anterior skull base meningiomas; the mean tumor volume was 14.7 ± 15.4 cm³ (range 2.2-66.1 cm³), and the mean follow-up duration was 42.2 ± 37.1 months (range 2-144 months). Of 19 patients with olfactory groove meningiomas, 10 had preserved olfaction and underwent SKM, and preservation of olfaction in was seen in 60%. Of 9 patients who presented without olfaction, 8 had cribriform plate invasion and underwent combined SKM and EEA (n = 3), bifrontal craniotomy (n = 3), or EEA (n = 2), and one patient without both olfaction and cribriform plate invasion underwent SKM. GTR was achieved in 94.7%. Of 38 TS/PS meningiomas, 36 of the lesions were treated according to the algorithm. Of these 36 meningiomas, 30 were treated by EEA and 6 by craniotomy. GTR was achieved in 97.2%, with no visual deterioration and one CSF leak that resolved by placement of a lumbar drain. Two patients with tumors that, based on the algorithm, were not amenable to an EEA underwent EEA nonetheless: one had GTR and the other had a residual tumor that was followed and removed via craniotomy 9 years later. CONCLUSIONS Utilizing a simple algorithm aimed at preserving olfaction and vision and based on maximizing use of minimally invasive approaches and selective use of transcranial approaches, the authors found that excellent outcomes can be achieved for anterior skull base meningiomas.

Transbasal versus endoscopic endonasal versus combined approaches for olfactory groove meningiomas: importance of approach selection

OBJECTIVE There has been much debate regarding the optimal surgical approach for resecting olfactory groove meningiomas (OGMs). In this paper, the authors analyzed the factors involved in approach selection and reviewed the surgical outcomes in a series of OGMs. METHODS A retrospective review of 28 consecutive OGMs from a prospective database was conducted. Each tumor was treated via one of 3 approaches: transbasal approach (n = 15), pure endoscopic endonasal approach (EEA; n = 5), and combined (endoscope-assisted) transbasal-EEA (n = 8). RESULTS The mean tumor volume was greatest in the transbasal (92.02 cm³) and combined (101.15 cm³) groups. Both groups had significant lateral dural extension over the orbits (transbasal 73.3%, p < 0.001; combined 100%), while the transbasal group had the most cerebral edema (73.3%, p < 0.001) and vascular involvement (66.7%, p < 0.001), and the least presence of a cortical cuff (33.3%, p = 0.019). All tumors in the combined group were recurrent tumors that invaded into the sinonasal cavity. The purely EEA group had the smallest mean tumor volume (33.33 cm³), all with a cortical cuff and no lateral dural extension. Gross-total resection was achieved in 80% of transbasal, 100% of EEA, and 62.5% of combined cases. Near-total resection (> 95%) was achieved in 20% of transbasal and 37.5% of combined cases, all due to tumor adherence to the critical neurovascular structures. The rate of CSF leakage was 0% in the transbasal and combined groups, and there was 1 leak in the EEA group (20%), resulting in an overall CSF leakage rate of 3.6%. Olfaction was preserved in 66.7% in the transbasal group. There was no significant difference in length of stay or 30-day readmission rate between the 3 groups. The mean modified Rankin Scale score was 0.79 after the transbasal approach, 2.0 after EEA, and 2.4 after the combined approach (p = 0.0604). The mean follow-up was 14.5 months (range 1-76 months). CONCLUSIONS The transbasal approach provided the best clinical outcomes with the lowest rate of complications for large tumors (> 40 mm) and for smaller tumors (< 40 mm) with intact olfaction. The role of EEA appears to be limited to smaller, appropriately selected tumors in which olfaction is already absent. EEA also plays an important adjunctive role when combined with the transbasal approach for recurrent OGMs invading the sinonasal cavity. Careful patient selection using an individualized, tailored strategy is important to optimize surgical outcomes.

The medial wall of the cavernous sinus. Part 2: Selective medial wall resection in 50 pituitary adenoma patients

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.

Anatomical assessment of the endoscopic endonasal approach for the treatment of paraclinoid aneurysms

OBJECTIVE

Endoscopic endonasal approaches (EEAs) are increasingly being incorporated into the neurosurgeon's armamentarium for treatment of various pathologies, including paraclinoid aneurysms. However, few anatomical assessments have been performed on the use of EEA for this purpose. The aim of the present study was to provide a comprehensive anatomical assessment of the EEA for the treatment of paraclinoid aneurysms.

METHODS

Five cadaveric heads underwent an endonasal transplanum-transtuberculum approach to expose the paraclinoid area. The feasibility of obtaining proximal and distal internal carotid artery (ICA) control as well as the topographic location of the origin of the ophthalmic artery (OphA) relative to dural landmarks were assessed. Limitations of the EEA in exposing the supraclinoid ICA were also recorded to identify favorable paraclinoid ICA aneurysm projections for EEA.

RESULTS

The extracavernous paraclival and clinoidal ICAs were favorable segments for establishing proximal control. Clipping the extracavernous ICA risked injury to the trigeminal and abducens nerves, whereas clipping the clinoidal segment put the oculomotor nerve at risk. The OphA origin was found within 4 mm of the medial opticocarotid point on a line connecting the midtubercular recess point to the medial vertex of the lateral opticocarotid recess. An average 7.2-mm length of the supraclinoid ICA could be safely clipped for distal control. Assessments showed that small superiorly or medially projecting aneurysms were favorable candidates for clipping via EEA.

CONCLUSIONS

When used for paraclinoid aneurysms, the EEA carries certain risks to adjacent neurovascular structures during proximal control, dural opening, and distal control. While some authors have promoted this approach as feasible, this work demonstrates that it has significant limitations and may only be appropriate in highly selected cases that are not amenable to coiling or clipping. Further clinical experience with this approach helps to delineate its risks and benefits.

Selection of endoscopic or transcranial surgery for tuberculum sellae meningiomas according to specific anatomical features: a retrospective multicenter analysis (KOSEN-002)

OBJECTIVE

The endoscopic endonasal approach (EEA) and the transcranial approach (TCA) are good options for the treatment of tuberculum sellae (TS) meningiomas. The objective of this study was to identify the key anatomical features in TS meningiomas and compare the two surgical approaches.

METHODS

The authors retrospectively reviewed clinical data in 178 patients with TS meningiomas treated at 3 institutions between January 2010 and July 2016. Patients with tumors encasing the internal carotid artery or anterior cerebral artery or involving the anterior clinoid process or cavernous sinus were excluded. Tumors were classified as high-lying or low-lying based on their location, and involvement of the optic canal was evaluated. The surgical outcomes of EEA and TCA were analyzed according to the relevant anatomical features.

RESULTS

During the study period, 84 patients underwent EEA and 94 patients underwent TCA. Based on preoperative MR images, 43 (24.2%) meningiomas were classified as high-lying tumors, 126 (70.8%) as low-lying, and 9 (5.0%) as nonspecific. Gross-total resection (GTR) was performed in 145 patients (81.5%); the GTR rate did not differ significantly between the EEA and TCA groups. Of 157 patients with preoperative visual disturbance, 140 had improved or stable vision postoperatively. However, 17 patients (9.6%) experienced some visual deterioration after surgery. The TCA group had a worse visual outcome than the EEA group in patients with preoperative optic canal involvement (77.6% vs 93.2%, p = 0.019), whereas there was no significant difference in visual outcome based on whether tumors were high-lying or low-lying.

CONCLUSIONS

The results of this study support EEA over TCA, at least with respect to visual improvement with acceptable complications, although TCA is still an effective approach for TS meningioma.

Contralateral transmaxillary corridor: an augmented endoscopic approach to the petrous apex

OBJECTIVE The endoscopic endonasal approach (EEA) has been shown to be an effective means of accessing lesions of the petrous apex. Lesions that are lateral to the paraclival segment of the internal carotid artery (ICA) require lateralization of the paraclival segment of the ICA or a transpterygoid infrapetrous approach. In this study the authors studied the feasibility of adding a contralateral transmaxillary (CTM) corridor to provide greater access to the petrous apex with decreased need for manipulation of the ICA. METHODS Using image guidance, EEA and CTM extension were performed bilaterally on 5 cadavers. The anterior wall of the sphenoid sinus and rostrum were removed. The angle of the surgical approach from the axis of the petrous segment of the ICA was measured. Five illustrative clinical cases are presented. RESULTS The CTM corridor required a partial medial maxillectomy. When measured from the axis of the petrous ICA, the CTM corridor decreased the angle from 44.8° ± 2.78° to 20.1° ± 4.31°, a decrease of 24.7° ± 2.58°. Drilling through the CTM corridor allowed the drill to reach lateral aspects of the petrous apex that would have required lateralization of the ICA or would not have been accessible via EEA. The CTM corridor allowed us to achieve gross-total resection of the petrous apex region in 5 clinical cases with significant paraclival extension. CONCLUSIONS The CTM corridor is a feasible extension to the standard EEA to the petrous apex that offers a more lateral trajectory with improved access. This approach may reduce the risk and morbidity associated with manipulation of the paraclival ICA.

Endoscopic endonasal approach for craniopharyngioma: the importance of the relationship between pituitary stalk and tumor

OBJECTIVE The endoscopic endonasal approach (EEA) is commonly used for the treatment of craniopharyngioma; therefore, it is essential to analyze outcomes in order to understand the benefits and drawbacks. The goal of this paper was to evaluate the clinical features and outcomes associated with this treatment approach. METHODS From July 2010 to March 2016, 82 adult craniopharyngioma patients underwent an EEA at the authors' institution. Of these cases, intraoperative records and immediate postoperative MR images were available for 68 patients. The patients underwent systemized endocrinological evaluation. Eighteen of 68 patients who underwent EEA for recurrence or regrowth of residual lesions after previous surgical management were excluded in the analysis of the anatomical tumor classification. The authors retrospectively analyzed preoperative clinical features and previous anatomical classifications, focusing on the relationship of the pituitary stalk and tumor, to determine predictive factors for the clinical outcome, such as the extent of resection, visual function, endocrinological function, recurrence rate, and complications. RESULTS The mean tumor size was 2.5 cm (3.1 cm for primary tumors and 1.9 cm for recurrent lesions). Gross-total resection (GTR) was achieved in 62 (91.1%) patients (48 [96.0%] patients with primary tumors and 14 [77.8%] patients with recurrent tumors). The rate of GTR was higher in the primary group than in the group with recurrence (p = 0.038). The overall pre- and postoperative visual impairment scale (VIS) scores were 40.8 and 22.1, respectively (50.9 and 14.3 in the primary group and 30.7 and 29.9 in patients with recurrence, respectively). The improvement rate in VIS score was higher in the primary group than in the recurrent group (p = 0.001). Endocrinological function was improved in 4 patients (5.9%) and deteriorated in 32 of 68 patients (47.1%). Tumor invasion into the center of the pituitary stalk affected the postoperative outcomes most significantly. Cognitive dysfunction was observed in 22 patients before surgery and improved in 20 patients (90.9%) after surgery. Hydrocephalus was found in 7 patients and resolved after surgery in all cases. CSF leakage occurred in 2 (2.9%) of 68 patients and was repaired by revision surgery in both patients. Ten patients without CSF leakage also received antibiotics for the treatment of meningitis. The infection rate was higher in the recurrent group. Postoperative endocrinological evaluation showed no deficits in 12 patients and panhypopituitarism in 55 patients. The remaining patient had growth hormone deficiency. Forty-three patients had new-onset diabetes insipidus, and 1 patient had persistent diabetes insipidus after surgery. There were 2 (2.9%) cases of recurrence during the mean 30.7-month follow-up period; one patient underwent radiosurgery and the other underwent reoperation. CONCLUSIONS The EEA resulted in excellent surgical outcomes and acceptable morbidity rates, regardless of the anatomical location of the tumor. Invasion of the craniopharyngioma into the center of the pituitary stalk has strong predictive power for postoperative endocrinological outcome.

Reoperation for growth hormone-secreting pituitary adenomas: report on an endonasal endoscopic series with a systematic review and meta-analysis of the literature

OBJECTIVE Surgery is generally the first-line therapy for acromegaly. For patients with residual or recurrent tumors, several treatment options exist, including repeat surgery, medical therapy, and radiation. Reoperation for recurrent acromegaly has been associated with poor results, with hormonal control usually achieved in fewer than 50% of cases. Extended endonasal endoscopic approaches (EEAs) may potentially improve the results of reoperation for acromegaly by providing increased visibility and maneuverability in parasellar areas. METHODS A database of all patients treated in the authors' center between July 2004 and February 2016 was reviewed. Cases involving patients with acromegaly secondary to growth hormone (GH)-secreting adenomas who underwent EEA were selected for chart review and divided into 2 groups: first-time surgery and reoperation. Disease control was defined by 2010 guidelines. Clinical and radiological characteristics and outcome data were extracted. A systematic review was done through a MEDLINE database search (2000-2016) to identify studies on the surgical treatment of acromegaly. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the included studies were reviewed for surgical approach, tumor size, cavernous sinus invasion, disease control, and complications. Cases were divided into reoperation or first-time surgery for comparative analysis. RESULTS A total of 44 patients from the authors' institution were included in this study. Of these patients, 2 underwent both first-time surgery and reoperation during the study period and were therefore included in both groups. Thus data from 46 surgical cases were analyzed (35 first-time operations and 11 reoperations). The mean length of follow-up was 70 months (range 6-150 months). The mean size of the reoperated tumors was 14.8 ± 10.0 mm (5 micro- and 6 macroadenomas). The patients' mean age at the time of surgery was younger in the reoperation group than in the first-time surgery group (34.3 ± 12.8 years vs 49.1 ± 15.7 years, p = 0.007) and the mean preoperative GH level was also lower (7.7 ± 13.1 μg/L vs 25.6 ± 36.8 μg/L, p = 0.04). There was no statistically significant difference in disease control rates between the reoperation (7 [63.6%] of 11) and first-time surgery (25 [71.4%] of 33) groups (p = 0.71). Univariate analysis showed that older age, smaller tumor size, lower preoperative GH level, lower preoperative IGF-I level, and absence of cavernous sinus invasion were associated with higher chances of disease control in the first-time surgery group, whereas only absence of cavernous sinus invasion was associated with disease control in the reoperation group (p = 0.01). There was 1 case (9%) of transient diabetes insipidus and hypogonadism and 1 (9%) postoperative nasal infection after reoperation. The systematic review retrieved 29 papers with 161 reoperation and 2189 first-time surgery cases. Overall disease control for reoperation was 46.8% (95% CI 20%-74%) versus 56.4% (95% CI 49%-63%) for first-time operation. Reoperation and first-time surgery had similar control rates for microadenomas (73.6% [95% CI 32%-98%] vs 77.6% [95% CI 68%-85%]); however, reoperation was associated with substantially lower control rates for macroadenomas (27.5% [95% CI 5%-57%] vs 54.3% [95% CI 45%-62%]) and tumors invading the cavernous sinus (14.7% [95% CI 4%-29%] vs 38.5% [95% CI 27%-50%]). CONCLUSIONS Reoperative EEA for acromegaly had results similar to those for first-time surgery and rates of control for macroadenomas that were better than historical rates. Cavernous sinus invasion continues to be a negative prognostic indicator for disease control; however, results with EEA show improvement compared with results reported in the prior literature.

Cavernous sinus compartments from the endoscopic endonasal approach: anatomical considerations and surgical relevance to adenoma surgery

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.

Nasoseptal flap necrosis: a rare complication of endoscopic endonasal surgery

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.

Endoscopic endonasal odontoid resection with real-time intraoperative image-guided computed tomography: report of 4 cases

The authors present 4 cases in which they used intraoperative CT (iCT) scanning to provide real-time image guidance during endonasal odontoid resection. While intraoperative CT has previously been used as a confirmatory test after resection, to the authors' knowledge this is the first time it has been used to provide real-time image guidance during endonasal odontoid resection. The operating room setup, as well as the advantages and pitfalls of this approach, are discussed. A mobile intraoperative CT scanner was used in conjunction with real-time craniospinal neuronavigation in 4 patients who underwent endoscopic endonasal odontoidectomy for basilar invagination. All patients underwent a successful decompression. In 3 of the 4 patients, real-time intraoperative CT image guidance was instrumental in achieving a comprehensive decompression. In 3 (75%) cases in which the right nostril was the predominant working channel, there was a tendency for asymmetrical decompression toward the right side, meaning that residual bone was seen on the left, which was subsequently removed prior to completion of the surgery. Endoscopic endonasal odontoid resection with real-time intraoperative image-guided CT scanning is feasible and provides accurate intraoperative localization of pathology, thereby increasing the chance of a complete odontoidectomy. For right-handed surgeons operating predominantly through the right nostril, special attention should be paid to the contralateral side of the resection, where there is often a tendency for residual pathology.

Risk factors associated with postoperative cerebrospinal fluid leak after endoscopic endonasal skull base surgery

OBJECTIVE The aim in this paper was to determine risk factors for the development of a postoperative CSF leak after an endoscopic endonasal approach (EEA) for resection of skull base tumors. METHODS A retrospective review of patients who underwent EEA for the resection of intradural pathology between January 1997 and June 2012 was performed. Basic demographic data were collected, along with patient body mass index (BMI), tumor pathology, reconstruction technique, lumbar drainage, and outcomes. RESULTS Of the 615 patients studied, 103 developed a postoperative CSF leak (16.7%). Sex and perioperative lumbar drainage did not affect CSF leakage rates. Posterior fossa tumors had the highest rate of CSF leakage (32.6%), followed by anterior skull base lesions (21.0%) and sellar/suprasellar lesions (9.9%) (p < 0.0001). There was a higher leakage rate for overweight and obese patients (BMI > 25 kg/m²) than for those with a healthy-weight BMI (18.7% vs 11.5%; p = 0.04). Patients in whom a pedicled vascularized flap was used for reconstruction had a lower leakage rate than those in whom a free graft was used (13.5% vs 27.8%; p = 0.0015). In patients with a BMI > 25 kg/m², the use of a pedicled flap reduced the rate of CSF leakage from 29.5% to 15.0% (p = 0.001); in patients of normal weight, this reduction did not reach statistical significance (21.9% [pedicled flap] vs 9.2% [free graft]; p = 0.09). CONCLUSIONS Preoperative BMI > 25 kg/m² and tumor location in the posterior fossa were associated with higher rates of postoperative CSF leak. Use of a pedicled vascularized flap may be associated with reduced risk of a CSF leak, particularly in overweight patients.

Clival chordomas: considerations after 16 years of endoscopic endonasal surgery

OBJECTIVE In the past decade, the role of the endoscopic endonasal approach (EEA) has relevantly evolved for skull base tumors. In this study, the authors review their surgical experience with using an EEA in the treatment of clival chordomas, which are deep and infiltrative skull base lesions, and they highlight the advantages and limitations of this ventral approach. METHODS All consecutive cases of chordoma treated with an EEA between 1998 and 2015 at a single institution are included in this study. Preoperative assessment consisted of neuroimaging (MRI and CT with angiography sequences) and endocrinological, neurological, and ophthalmological evaluations, which were repeated 3 months after surgery and annually thereafter. Postoperative adjuvant therapies were considered. RESULTS Sixty-five patients (male/female ratio 1:0.9) were included in this study. The median age was 48 years (range 9-80 years). Gross-total resection (GTR) was achieved in 47 cases (58.7%). On univariate analysis, primary procedures (p = 0.001), location in the superior or middle third of the clivus (p = 0.043), extradural location (p = 0.035), and histology of conventional chordomas (p = 0.013) were associated with a higher rate of GTR. The complication rate was 15.1%, and there were no perioperative deaths. Most complications did not result in permanent sequelae and included 2 CSF leaks (2.5%), 5 transient cranial nerve VI palsies (6.2%), and 2 internal carotid artery injuries (2.5%), which were treated with coil occlusion of the internal carotid artery without neurological deficits. Three patients (3.8%) presented with complications resulting in permanent neurological deficits due to a postoperative hematoma (1.2%) causing a hemiparesis, and 2 permanent ophthalmoplegias (2.5%). Seventeen patients (26.2%) have died of tumor progression over the course of follow-up (median 52 months, range 7-159 months). Based on Kaplan-Meier analysis, the survival rate was 77% at 5 years and 57% at 10 years. On multivariate analysis, the extent of tumor removal (p = 0.001) and the absence of previous treatments (p = 0.001) proved to be correlated with a longer survival rate. CONCLUSIONS The EEA was associated with a high rate of tumor removal and symptom control, with low morbidity and preservation of a good quality of life. These results allow for a satisfactory overall survival rate, particularly after GTR and for primary surgery. Considering these results, the authors believe that an EEA can be a helpful tool in chordoma surgery, achieving a good balance between as much tumor removal as possible and the preservation of an acceptable patient quality of life.

Complete endoscopic resection of a pituitary stalk epidermoid cyst using a combined infrasellar interpituitary and suprasellar endonasal approach: case report

Intracranial epidermoid cysts are benign lesions of epithelial origin that most frequently present with symptoms of mass effect. Although they are often associated with a high rate of residual tumor and recurrence, maximal safe resection usually leads to good outcomes. The authors report a complete resection of an uncommon pituitary stalk epidermoid cyst with intrasellar extension using a combined suprasellar and infrasellar interpituitary, endoscopic endonasal transsphenoidal approach. The patient, a 54-year-old woman, presented with headache, visual disturbance, and diabetes insipidus. Postoperatively, she reported improvement in her visual symptoms and well-controlled diabetes insipidus using 0.1 mg of desmopressin at bedtime and normal anterior pituitary gland function. One year later, she continues to receive the same dosage of desmopressin and is also taking 50 mcg of levothyroxine daily after developing primary hypothyroidism unrelated to the surgical procedure. A combined infrasellar interpituitary and suprasellar approach to this rare location for an epidermoid cyst can lead to a safe and complete resection with good clinical outcomes.

Endoscopic endonasal versus open transcranial resection of craniopharyngiomas: a case-matched single-institution analysis

OBJECTIVE The authors compared clinical and radiological outcomes after resection of midline craniopharyngiomas via an endoscopic endonasal approach (EEA) versus an open transcranial approach (TCA) at a single institution in a series in which the tumors were selected to be equally amenable to gross-total resection (GTR) with either approach. METHODS A single-institution retrospective review of previously untreated adult midline craniopharyngiomas was performed. Lesions were evaluated by 4 neurosurgeons blinded to the actual approach used to identify cases that were equally amenable to GTR using either an EEA or TCA. Radiological and clinical outcome data were assessed. RESULTS Twenty-six cases amenable to either approach were identified, 21 EEA and 5 TCA. Cases involving tumors that were resected via a TCA had a trend toward larger diameter (p = 0.10) but were otherwise equivalent in preoperative clinical and radiological characteristics. GTR was achieved in a greater proportion of cases removed with an EEA than a TCA (90% vs 40%, respectively; p = 0.009). Endoscopic resection was associated with superior visual restoration (63% vs 0%; p < 0.05), a decreased incidence of recurrence (p < 0.001), lower increase in FLAIR signal postoperatively (-0.16 ± 4.6 cm³ vs 14.4 ± 14.0 cm³; p < 0.001), and fewer complications (20% vs 80% of patients; p < 0.001). Significantly more TCA patients suffered postoperative cognitive loss (80% vs 0; p < 0.0001). CONCLUSIONS An EEA is a safe and effective approach to suprasellar craniopharyngiomas amenable to GTR. For this select group of cases, the EEA may provide higher rates of GTR and visual improvement with fewer complications compared with a TCA.

Microscopic versus endoscopic approaches for craniopharyngiomas: choosing the optimal surgical corridor for maximizing extent of resection and complication avoidance using a personalized, tailored approach

Resection remains the mainstay of treatment for craniopharyngiomas with the goal of radical resection, if safely possible, to minimize the rate of recurrence. Endoscopic endonasal and microscopic transcranial surgical approaches have both become standard methods for the treatment for craniopharyngiomas. However, the approach selection paradigm for craniopharyngiomas is still a point of discussion. Choosing the optimal surgical approach can play a significant role in maximizing the extent of resection and surgical outcome while minimizing the risks of potential complications. Craniopharyngiomas can present with a variety of different sizes, locations, and tumor consistencies, and each individual tumor has distinct features that favor one specific approach over another. The authors review standard cranial base techniques applied to craniopharyngioma surgery, using both the endoscopic endonasal approach and traditional open microsurgical approaches, and analyze factors involved in approach selection. They discuss their philosophy of approach selection based on the location and extent of the tumor on preoperative imaging as well as the advantages and limitations of each surgical corridor, and they describe the operative nuances of each technique, using a personalized, tailored approach to the individual patient with illustrative cases and videos.

Management and outcome of recurrent adult craniopharyngiomas: an analysis of 42 cases with long-term follow-up

OBJECTIVE The treatment of recurrent and residual craniopharyngiomas is challenging. In this study the authors describe their experience with these tumors and make recommendations on their management. METHODS The authors performed an observational study of adult patients (≥ 18 years) with recurrent or residual craniopharyngiomas that were managed at their tertiary center. Retrospective data were collected on demographics and clinical, imaging, and treatment characteristics from patients who had a minimum 2-year follow-up. Descriptive statistics were used and the data were analyzed. RESULTS There were 42 patients (27 male, 15 female) with a mean age of 46.3 ± 14.3 years. The average tumor size was 3.1 ± 1.1 cm. The average time to first recurrence was 3.6 ± 5.5 years (range 0.2-27 years). One in 5 patients (8/42) with residual/recurrent tumors did not require any active treatment. Of the 34 patients who underwent repeat treatment, 12 (35.3%) had surgery only (transcranial, endoscopic, or both), 9 (26.5%) underwent surgery followed by adjuvant radiation therapy (RT), and 13 (38.2%) received RT alone. Eighty-six percent (18/21) had a gross-total (n = 4) or near-total (n = 14) resection of the recurrent/residual tumors and had good local control at last follow-up. One of 5 patients (7/34) who underwent repeat treatment had further treatment for a second recurrence. The total duration of follow-up was 8.6 ± 7.1 years. The average Karnofsky Performance Scale score at last follow-up was 80 (range 40-90). There was 1 death. CONCLUSIONS Based on this experience and in the absence of guidelines, the authors recommend an individualized approach for the treatment of symptomatic or growing tumors. This study has shown that 1 in 5 patients does not require repeat treatment of their recurrent/residual disease and can be managed with a "scan and watch" approach. On the other hand, 1 in 5 patients who had repeat treatment for their recurrence in the form of surgery and/or radiation will require further additional treatment. More studies are needed to best characterize these patients and predict the natural history of this disease and response to treatment.

Anatomical nuances of the internal carotid artery in relation to the quadrangular space

OBJECTIVE The aim of this study was to evaluate the anatomical variations of the internal carotid artery (ICA) in relation to the quadrangular space (QS) and to propose a classification system based on the results. METHODS A total of 44 human cadaveric specimens were dissected endonasally under direct endoscopic visualization. During the dissection, the anatomical variations of the ICA and their relationship with the QS were noted. RESULTS The space between the paraclival ICAs (i.e., intercarotid space) can be classified as 1 of 3 different shapes (i.e., trapezoid, square, or hourglass) based on the trajectory of the ICAs. The ICA trajectories also directly influence the volumetric area of the QS. Based on its geometry, the QS was classified as one of the following: 1) Type A has the smallest QS area and is associated with a trapezoid intercarotid space, 2) Type B corresponds to the expected QS area (not minimized or enlarged) and is associated with a square intercarotid space, and 3) Type C has the largest QS area and is associated with an hourglass intercarotid space. CONCLUSIONS The different trajectories of the ICAs can modify the area of the QS and may be an essential parameter to consider for preoperative planning and defining the most appropriate corridor to reach Meckel's cave. In addition, ICA trajectories should be considered prior to surgery to avoid injuring the vessels.

Clinical features and surgical outcomes of patients with skull base chordoma: a retrospective analysis of 238 patients

OBJECTIVE Skull base chordoma is relatively rare, and a limited number of reports have been published regarding its clinical features. Moreover, the factors associated with extent of resection, as well as the value of marginal resection for long-term survival, are still in question for this disease. The objective of this study was to investigate these factors by evaluating their clinical features and surgical outcomes. METHODS A retrospective analysis of 238 patients with skull base chordomas, who met the inclusion criteria, was performed. This study summarized the clinical features, selection of approaches, degree of resection, and postoperative complications by statistical description analyses; proposed modified classifications of tumor location and bone invasion; studied the contributions of the clinical and radiological factors to the extent of resection by Pearson χ², ANOVA, rank test, and binary logistic regression analysis; and estimated the differences in overall survival and progression-free survival rates with respect to therapeutic history, classification of tumor location, extent of bone invasion, and extent of tumor resection by the Kaplan-Meier method. A p value < 0.05 was considered statistically significant. RESULTS The study included 140 male and 98 female patients with a mean age of 38.1 years. Headache and neck pain (33.2%) and diplopia (29%) were the most common initial symptoms. Sphenoclival type accounted for the largest proportion of tumor location (59.2%); endophytic chordoma was the more common type of bone invasion (81.5%). Lateral open approaches were performed in two-thirds of the study population (78.6%). The rate of marginal resection was 66%, composed of gross-total resection (11.8%) and near-total resection (54.2%). Meningitis (8%) and CSF leakage (3.8%) were the most frequent complications. The mean follow-up period was 43.7 months. The overall survival and progression-free survival rates at 5 years were 76% and 45%, respectively. Recurrent tumor and larger tumor volume (≥ 40 cm³) were identified as risk factors of marginal resection. Patients who presented with recurrent tumor and underwent intralesional resection had a worse long-term outcome. CONCLUSIONS The classifications of both tumor location and bone invasion demonstrated clinical value. Marginal resection was more likely to be achieved for primary lesions with smaller volumes (< 40 cm³). The rate of CSF leakage declined due to improved dura mater repair with free fat grafts. Marginal resection, or gross-total resection when possible, should be performed in patients with primary chordomas to achieve better long-term survival.

Postoperative outcome of body core temperature rhythm and sleep-wake cycle in third ventricle craniopharyngiomas

OBJECTIVE One of the more serious risks in the treatment of third ventricle craniopharyngiomas is represented by hypothalamic damage. Recently, many papers have reported the expansion of the indications for the endoscopic endonasal approach (EEA) to be used for these tumors as well. The aim of this study was to assess the outcome of sleep-wake cycle and body core temperature (BCT), both depending on hypothalamic control, in patients affected by craniopharyngiomas involving the third ventricle that were surgically treated via an EEA. METHODS All consecutive adult patients with craniopharyngiomas that were treated at one center via an EEA between 2014 and 2016 were prospectively included. Each patient underwent neuroradiological, endocrinological, and ophthalmological evaluation; 24-hour monitoring of the BCT rhythm; and the sleep-wake cycle before surgery and at follow-up of at least 6 months. RESULTS Ten patients were included in the study (male/female ratio 4:6, mean age 48.6 years, SD 15.9 years). Gross-total resection was achieved in 8 cases. Preoperative BCT rhythm was pathological in 6 patients. After surgery, these disturbances resolved in 2 cases, improved in another 3, and remained the same in 1 patient; also, 1 case of de novo onset was observed. Before surgery the sleep-wake cycle was pathological in 8 cases, and it was restored in 4 patients at follow-up. After surgery the number of patients reporting diurnal naps increased from 7 to 9. CONCLUSIONS The outcome of the sleep-wake cycle and BCT analyzed after EEA in this study is promising. Despite the short duration of the authors' experience, they consider these results encouraging; additional series are needed to confirm the preliminary findings.

Predicting the limits of the endoscopic endonasal approach in children: a radiological anatomical study

OBJECT The endoscopic endonasal approach (EEA) has been established as an alternative approach to craniovertebral junction (CVJ) pathology in adults. The authors have previously described the nasoaxial line (NAxL) as an accurate predictor of the lower limit of the EEA to the CVJ in adults. The surgical anatomy limiting the EEA to the pediatric CVJ has not been well studied. Furthermore, predicting the lower limit of the EEA in various pediatric age groups is important in surgical planning. To better understand the anatomy affecting the EEA to the CVJ, the authors examined the skull base anatomy relevant to the EEA in children of different age groups and used the NAxL to predict the EEA lower limit in children. METHODS Axial brain CT scans of 39 children with normal skull base anatomy were reconstructed sagittally. Children were divided into 4 groups according to age: 3-6, 7-10, 11-14, and 15-18 years old. The intersection of the NAxL with the odontoid process of C-2 was described for each group. Analyses of variance were used to estimate the effect of age, sex, interaction between age and sex on different anatomical parameters relevant to the endonasal corridor (including the length of the hard palate [HPLe]), dimensions of choana and piriform aperture, and the length of the NAxL to C-2. The effect of the HPLe on the working distance of NAxL to the odontoid was also estimated using analysis of covariance, controlling for age, sex, and their interaction. RESULTS The NAxL extended to the odontoid process in 38 of the 39 children. Among the 39 children, the NAxL intersected the upper third of the odontoid process in 25 while intersecting the middle third in the remaining 13 children. The measurements of the inferior limits did not differ with age, varying between 9 and 11 mm below the hard palate line at the ventral surface of C-2. Significant increases in the size of the piriform aperture and choana and the HPLe were observed after age 10. The HPLe predicted the length of the NAxL (p < 0.0001). CONCLUSIONS The caudal limit of the EEA extends as far as the middle third of the odontoid process in children, as predicted by the NAxL. The most prominent increase in the size of the choana and piriform aperture occurs after age 10. The HPLe is a significant predictor of the working distance to C-2. Utilizing the NAxL preoperatively may help in planning the EEA to the CVJ in children.

Pediatric skull base reconstruction: case report of a tunneled temporoparietal fascia flap

The authors of this report present a pediatric case involving the use of a tunneled temporoparietal fascia flap to reconstruct a skull base defect for a multiply recurrent clival chordoma and cerebrospinal fluid leak, demonstrate the surgical technique through illustrations and intraoperative photos, and review the pertinent literature. A 9-year-old female patient underwent extensive clival chordoma resection via both the endoscopic and open approaches, which ultimately exhausted the bilateral nasoseptal flaps and other intranasal reconstructive options. Following proton beam radiation and initiation of chemotherapy, tumor recurrence was managed with further endoscopic resection, which was complicated by a recalcitrant cerebrospinal fluid leak. A tunneled temporoparietal fascia flap was used to provide vascular tissue to augment an endoscopic repair of the leak and reconstruction of the skull base. While the nasoseptal flap remains the workhorse for many pediatric and adult endoscopic skull base reconstructions, the tunneled temporoparietal fascia flap has a demonstrated efficacy in adults when the nasoseptal flap and other intranasal flaps are unavailable. This report documents a pediatric case, serving as a step toward establishing this technique in the pediatric population.

Comparative analysis of the anterior transpetrosal approach with the endoscopic endonasal approach to the petroclival region

OBJECTIVE The endoscopic endonasal approach (EEA) offers direct access to midline skull base lesions, and the anterior transpetrosal approach (ATPA) stands out as a method for granting entry into the upper and middle clival areas. This study evaluated the feasibility of performing EEA for tumors located in the petroclival region in comparison with ATPA. METHODS On 8 embalmed cadaver heads, EEA to the petroclival region was performed utilizing a 4-mm endoscope with either 0° or 30° lenses, and an ATPA was performed under microscopic visualization. A comparison was executed based on measurements of 5 heads (10 sides). Case illustrations were utilized to demonstrate the advantages and disadvantages of EEA and ATPA when dealing with petroclival conditions. RESULTS Extradurally, EEA allows direct access to the medial petrous apex, which is limited by the petrous and paraclival internal carotid artery (ICA) segments laterally. The ATPA offers direct access to the petrous apex, which is blocked by the petrous ICA and abducens nerve inferiorly. Intradurally, the EEA allows a direct view of the areas medial to the cisternal segment of cranial nerve VI with limited lateral exposure. ATPA offers excellent access to the cistern between cranial nerves III and VIII. The quantitative analysis demonstrated that the EEA corridor could be expanded laterally with an angled drill up to 1.8 times wider than the bone window between both paraclival ICA segments. CONCLUSIONS The midline, horizontal line of the petrous ICA segment, paraclival ICA segment, and the abducens nerve are the main landmarks used to decide which approach to the petroclival region to select. The EEA is superior to the ATPA for accessing lesions medial or caudal to the abducens nerve, such as chordomas, chondrosarcomas, and midclival meningiomas. The ATPA is superior to lesions located posterior and/or lateral to the paraclival ICA segment and lesions with extension to the middle fossa and/or infratemporal fossa. The EEA and ATPA are complementary and can be used independently or in combination with each other in order to approach complex petroclival lesions.

Intraoperative neurophysiological monitoring during endoscopic endonasal surgery for pediatric skull base tumors

OBJECT The aim of this study was to evaluate the value of intraoperative neurophysiological monitoring (IONM) using electromyography (EMG), brainstem auditory evoked potentials (BAEPs), and somatosensory evoked potentials (SSEPs) to predict and/or prevent postoperative neurological deficits in pediatric patients undergoing endoscopic endonasal surgery (EES) for skull base tumors. METHODS All consecutive pediatric patients with skull base tumors who underwent EES with at least 1 modality of IONM (BAEP, SSEP, and/or EMG) at our institution between 1999 and 2013 were retrospectively reviewed. Staged procedures and repeat procedures were identified and analyzed separately. To evaluate the diagnostic accuracy of significant free-run EMG activity, the prevalence of cranial nerve (CN) deficits and the sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS A total of 129 patients underwent 159 procedures; 6 patients had a total of 9 CN deficits. The incidences of CN deficits based on the total number of nerves monitored in the groups with and without significant free-run EMG activity were 9% and 1.5%, respectively. The incidences of CN deficits in the groups with 1 staged and more than 1 staged EES were 1.5% and 29%, respectively. The sensitivity, specificity, and negative predictive values (with 95% confidence intervals) of significant EMG to detect CN deficits in repeat procedures were 0.55 (0.22-0.84), 0.86 (0.79-0.9), and 0.97 (0.92-0.99), respectively. Two patients had significant changes in their BAEPs that were reversible with an increase in mean arterial pressure. CONCLUSIONS IONM can be applied effectively and reliably during EES in children. EMG monitoring is specific for detecting CN deficits and can be an effective guide for dissecting these procedures. Triggered EMG should be elicited intraoperatively to check the integrity of the CNs during and after tumor resection. Given the anatomical complexity of pediatric EES and the unique challenges encountered, multimodal IONM can be a valuable adjunct to these procedures.

Evolution from microscopic transoral to endoscopic endonasal odontoidectomy

OBJECT

The goal of this study was to compare the indications, benefits, and complications between the endoscopic endonasal approach (EEA) and the microscopic transoral approach to perform an odontoidectomy. Transoral approaches have been standard for odontoidectomy procedures; however, the potential benefits of the EEA might be demonstrated to be a more innocuous technique. The authors present their experience with 12 consecutive cases that required odontoidectomy and posterior instrumentation.

METHODS

Twelve consecutive cases of craniovertebral junction instability with or without basilar invagination were diagnosed at the National Institute of Neurology and Neurosurgery in Mexico City, Mexico, between January 2009 and January 2013. The EEA was used for 5 cases in which the odontoid process was above the nasopalatine line, and was compared with 7 cases in which the odontoid process was beneath the nasopalatine line; these were treated using the transoral microscopic approach (TMA). Odontoidectomy was performed after occipital-cervical or cervical posterior augmentation with lateral mass and translaminar screws. One case was previously fused (Oc-C4 fusion). The senior author performed all surgeries. American Spinal Injury Association scores were documented before surgical treatment and after at least 6 months of follow-up.

RESULTS

Neurological improvement after odontoidectomy was similar for both groups. From the transoral group, 2 patients had postoperative dysphonia, 1 patient presented with dysphagia, and 1 patient had intraoperative CSF leakage. The endoscopic procedure required longer surgical time, less time to extubation and oral feeding, a shorter hospital stay, and no complications in this series.

CONCLUSIONS

Endoscopic endonasal odontoidectomy is a feasible, safe, and well-tolerated procedure. In this small series there was no difference in the outcome between the EEA and the TMA; however, fewer complications were documented with the endonasal technique.

Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension

OBJECT

Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions.

METHODS

Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas.

RESULTS

The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery.

CONCLUSIONS

Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.

Suprachiasmatic translamina terminalis corridor used in endoscopic endonasal approach for resecting third ventricular craniopharyngioma

OBJECT

The translamina terminalis corridor was used in the transcranial anterior route to treat third ventricular craniopharyngioma (TVC), which presents a challenge to neurosurgeons. The endoscopic endonasal approach (EEA) has recently been used to treat craniopharyngiomas. However, there are few reports of the EEA being used to treat TVC. The authors' novel surgical approach of treating selected TVC by the endoscopic endonasal route via the suprachiasmatic translamina terminalis (STLT) corridor is described.

METHODS

In this single-center study, the EEA via the STLT corridor was used to resect TVC with great upper and anterior extension causing bulged lamina terminalis, and TVC with a residual upper compartment, after routine infrachiasmatic transmetastalk corridor resection.

RESULTS

The STLT corridor was used in 3 patients. Gross-total resection was achieved in all cases. One patient achieved visual improvement, and the other 2 patients showed partial visual improvement. Leakage of CSF occurred in 1 patient. Postoperative hormone replacement therapy was required in all patients.

CONCLUSIONS

The STLT corridor is a complementary minimally invasive corridor used in the EEA for treating selected TVC. The STLT alone or combined with infrachiasmatic transmetastalk corridors should be selected depending on the size of suprachiasmatic and infrachiasmatic space.

Endoscopic endonasal surgery for suprasellar meningiomas: experience with 75 patients

OBJECT

Following the introduction of the neurosurgical microscope, the outcomes in suprasellar meningioma surgery were dramatically improved. More recently, the neurosurgical endoscope has been introduced as a visualization option during removal of skull base tumors, both transcranially and endonasally. The authors retrospectively reviewed the effectiveness of endoscopic endonasal surgery (EES) in the management of suprasellar meningiomas.

METHODS

Between 2002 and 2011, 75 patients (81.3% female) with suprasellar meningiomas underwent EES at the University of Pittsburgh Medical Center. The authors present the results of EES and analyze the resection rates, visual outcome, and complications.

RESULTS

Seventy-one patients presented with primary tumors, whereas 4 were previously treated elsewhere. Their mean age was 57.3 years (range 36-88 years), and most patients presented with visual loss (81.3%). Tumors occupied the tuberculum sellae (86.7%) and planum sphenoidale (50.7%), with extension into the optic canals in 26.7% (unilateral in 21.3% and bilateral in 5.3%) and the pituitary fossa (9.3%). Gross-total tumor resection (Simpson Grade I) was achieved in 76% of the cases in the whole cohort and in 81.4% of the patients in whom it was the goal of surgery. Tumor location and extension into the optic canals was not a limitation for total resection. Tumor size, configuration, and vascular encasement were significant factors that influenced the degree of resection (p < 0.0001). Vision was improved or normalized in 85.7% of the cases. Visual deterioration following EES occurred in 2 patients (3.6%). Complications included postoperative CSF leaks (25.3% overall, 16.1% in recent years) resulting in meningitis in 4 cases. One patient had an intraoperative injury of the artery of Heubner resulting in associated neurological deficit. Another elderly patient died within 1 month after EES due to cerebral vasospasm and multisystem impairment. No patient developed postoperative cerebral contusions, hemorrhage, or seizures. During a mean follow-up period of 29 months (range 1-98 months), 4 patients have shown recurrence, but only 1 required repeat EES.

CONCLUSIONS

With the goal of gross-total tumor resection and visual improvement, EES can achieve very good results, (comparable to microscopic approaches) for the treatment of suprasellar meningiomas. Avoidance of brain and optic nerve retraction, preservation of the vascularization of the optic apparatus, and wide decompression of the optic canals are the main advantages of EES for the treatment of suprasellar meningiomas, while CSF leaks remain a disadvantage.