Combined subtarsal contralateral transmaxillary retroeustachian and endoscopic endonasal approaches to the infrapetrous region

J Neurosurg 139:992–1001, 2023

The eustachian tube (ET) limits endoscopic endonasal access to the infrapetrous region. Transecting or mobilizing the ET may result in morbidities. This study presents a novel approach in which a subtarsal contralateral transmaxillary (ST-CTM) corridor is coupled with the standard endonasal approach to facilitate access behind the intact ET.

METHODS Eight cadaveric head specimens were dissected. Endoscopic endonasal approaches (EEAs) (i.e., transpterygoid and inferior transclival) were performed on one side, followed by ST-CTM and sublabial contralateral transmaxillary (SL-CTM) approaches on the opposite side, along with different ET mobilization techniques on the original side. Seven comparative groups were generated. The length of the cranial nerves, areas of exposure, and volume of surgical freedom (VSF) in the infrapetrous regions were measured and compared.

RESULTS Without ET mobilization, the combined ST-CTM/EEA approach provided greater exposure than EEA alone (mean ± SD 288.9 ± 40.66 mm 2 vs 91.7 ± 49.9 mm 2 ; p = 0.001). The VSFs at the ventral jugular foramen (JF), entrance to the petrous internal carotid artery (ICA), and lateral to the parapharyngeal ICA were also greater in ST-CTM/EEA than in EEA alone (p = 0.002, p = 0.002, and p < 0.001, respectively). EEA alone, however, provided greater VSF at the hypoglossal canal (HGC) than did ST-CTM/EEA (p = 0.01). The SL-CTM approach did not increase the EEA exposure (p = 0.48). The ST-CTM/EEA approach provided greater exposure than EEA with extended inferolateral (EIL) or anterolateral (AL) ET mobilization (p = 0.001 and p = 0.02, respectively). The ST-CTM/EEA also increased the VSF lateral to the parapharyngeal ICA in comparison with EEA/EIL ET mobilization (p < 0.001) but not with EEA/AL ET mobilization (p = 0.36). Finally, the VSFs at the HGC and JF were greater in EEA/AL ET mobilization than in ST-CTM/EEA without ET mobilization (p = 0.002 and p = 0.004, respectively).

CONCLUSIONS Combining the EEA with the more laterally and superiorly originating ST-CTM approach allows greater exposure of the infrapetrous and ventral JF regions while obviating the need for mobilizing the ET. The surgical freedom afforded by the combined approaches is greater than that obtained by EEA alone.

Clival Chordomas in the Endoscopic Endonasal Era: Comparison With Management With Open Skull Base Approaches

Neurosurgery 92:756–761, 2023

The most significant paradigm shift in surgical management of skull base chordomas has been the adoption of the endoscopic endonasal approach, but the impact on patient outcomes compared with open skull base approaches remains unclear.

OBJECTIVE: To compare a large series of patients treated by a single surgeon using primarily endoscopic endonasal approaches with previously published outcomes by the same surgeon using open skull base approaches.

METHODS: Between 2006 and 2020, 68 patients with skull base chordoma underwent resection using primarily endoscopic endonasal approaches. Outcomes and complications were compared with previously published results of resection of chordomas from 1991 to 2005 using open skull base approaches.

RESULTS: Compared with the prior cohort, the current principally endoscopic cohort demonstrated similar rates of OS (P = .86) and progression-free survival (P = .56), but patients undergoing first-time resection had significantly higher rates of radical resection (82.9% compared with 64.3%, P = .05) and required fewer staged surgeries (9.8% compared with 33.3%, P = .01).

CONCLUSION: There was no difference in survival rates for patients treated in the current era, primarily using endoscopic endonasal techniques, compared with previously published results using open skull-base approaches by the same surgeon. Although use of endoscopic endonasal approach resulted in higher rates of radical resection, patients undergoing first-time resection and fewer staged surgeries were required.

Clival Chordomas in the Endoscopic Endonasal Era: Clinical Management, Outcomes, and Complications

Neurosurgery 92:876–883, 2023

Surgical management of skull base chordomas has changed significantly in the past 2 decades, most notably with use of the endoscopic endonasal approach (EEA), although high quality outcome data using these modern approaches remain scarce.

OBJECTIVE: To evaluate outcomes in a large series of patients treated by a single surgeon, using primarily the EEA.

METHODS: Between 2006 and 2020, 68 patients with skull base chordoma underwent resection using mostly the EEA. Complications, outcomes, and potential contributing factors were evaluated using Kaplan-Meier survival analysis and univariable and multivariable Cox proportional hazards models.

RESULTS: Overall 5-year survival was 76.3% (95%CI 61.5%-86.0%), and 5-year progressionfree survival was 55.9%(95% CI 40.0%-69.0%). Inmultivariable analysis, radical resection was associated with significant reduction in risk of death (hazard ratio [HR] 0.04, 95% CI 0.005- 0.33, P = .003) and disease progression (HR 0.05, 95% CI 0.01-0.18, P < .001). Better preoperative function status reduced risk of death (HR 0.42 per 10-point increase in Karnofsky Performance Scale, 95% CI 0.28-0.63, P < .001) and progression (HR 0.60 per 10-point increase in Karnofsky Performance Scale, 95% CI 0.45-0.78, P < .001). Localization at the clivus reduced risk of death (HR 0.02, 95% CI 0.002-0.15, P < .001) and progression (HR 0.24, 95% CI 0.09-0.68, P = .007) compared with tumors at the craniovertebral junction.

CONCLUSION: In multivariable analysis, overall survival and progression-free survival of chordoma resection was most positively affected by radical resection, better preoperative functional status, and tumor location at the clivus rather than craniovertebral junction.

The endonasal midline inferior intercavernous approach to the cavernous sinus

Acta Neurochirurgica

https://doi.org/10.1007/s00701-022-05284-w

Traditional endoscopic endonasal approaches to the cavernous sinus (CS) open the anterior CS wall just medial to the internal carotid artery (ICA), posing risk of vascular injury. This work describes a potentially safer midline sellar entry point for accessing the CS utilizing its connection with the inferior intercavernous sinus (IICS) when anatomically present.

Methods The technique for the midline intercavernous dural access is described and depicted with cadaveric dissections and a clinical case.

Results An endoscopic endonasal approach exposed the periosteal dural layer of anterior sella and CS. The IICS was opened sharply in midline through its periosteal layer. The feather knife was inserted and advanced laterally within the IICS toward the anterior CS wall, thereby gradually incising the periosteal layer of the IICS. The knife was turned superiorly then inferiorly in a vertical direction to open the anterior CS wall. This provided excellent access to the CS compartments, maintained the meningeal layer of the IICS and the medial CS wall, and avoided an initial dural incision immediately adjacent to the ICA.

Conclusion The midline intercavernous dural access to the CS assisted by a 90° dissector-blade is an effective modification to previously described techniques, with potentially lower risk to the ICA.

Endoscopic Endonasal Transrotundum Middle Fossa Exposure: Technique of Transpterygoid Maxillary Nerve Transposition

World Neurosurg. (2018) 112:131-137

Middle fossa floor access can be challenging. Open skull base approaches have associated morbidity and yield suboptimal working angles around the temporal lobe. Endoscopic endonasal approaches to the middle fossa are poorly described, but provide an improved angle. I hypothesized that the length of the maxillary nerve can be transposed out of the foramen rotundum to provide a path to expose the full width of the middle fossa floor through the anterolateral and anteromedial triangle.

METHODS: Endoscopic endonasal transpterygoid dissections to expose the middle fossa were performed bilaterally on 2 silicone-injected cadaveric heads (4 sides). Transposition of V2 was then performed on all sides, and additional middle fossa exposure was achieved. Highresolution computed tomography imaging was obtained to quantify the extent of exposure. A transzygomatic approach was also performed for comparison.

RESULTS: The maxillary nerve was successfully transposed in each dissection. A periosteal fold was identified to assist in the mobilization of the infraorbital nerve. The average middle fossa exposure achieved without transposition was 50% (of the medial to lateral width). Transposition increased that to 95%. Comparison with the open transzygomatic approach demonstrated superior surgical trajectory (inferior to superior) with the endonasal route.

CONCLUSIONS: Endoscopic endonasal transpterygoid approaches with or without transposition of the maxillary nerve provide a reasonable option for sequentially exposing the entire medial to lateral extent of the anterolateral triangle. It provides an advantageous inferior to superior surgical angle and can be considered for treatment of select middle fossa floor pathology

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

J Neurosurg 128:1066–1071, 2018

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.

Endoscopic endonasal resection of the odontoid process

J Neurosurg 128:923–931, 2018

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.

Endoscopic endonasal transcavernous posterior clinoidectomy

Interdural pituitary transposition

J Neurosurg 121:91–99, 2014

The object of this paper was to describe the surgical anatomy and technical nuances of the endonasal transcavernous posterior clinoidectomy approach with interdural pituitary transposition and to report the clinical outcome of this technical modification.

Methods. The surgical anatomy of the proposed approach was studied in 10 colored silicon-injected anatomical specimens. The medical records of 12 patients that underwent removal of the posterior clinoid(s) with this technique were reviewed.

Results. The natural anatomical corridor provided by the cavernous sinus is used to get access to the posterior clinoid by mobilizing the pituitary gland in an interdural fashion. The medial wall of the cavernous sinus is preserved intact and attached to the gland during its medial and superior mobilization. This provides protection to the gland, allowing for preservation of its venous drainage pathways. The inferior hypophyseal artery is transected to facilitate the manipulation of the medial wall of the cavernous sinus and pituitary gland. This approach was successfully performed in all patients, including 6 with chordomas, 5 with petroclival meningiomas, and 1 with an epidermoid tumor. No patient in this series had neurovascular injury related to the posterior clinoidectomy. There were no instances of permanent hypopituitarism or diabetes insipidus.

Conclusions. The authors introduce a surgical variant of the endoscopic endonasal posterior clinoidectomy approach that does not require intradural pituitary transposition and is more effective than the purely extradural approach. The endoscopic endonasal transcavernous approach facilitates the removal of prominent posterior clinoids increasing the working space at the lateral recess of the interpeduncular cistern, while preserving the pituitary function.

The value of immediate postoperative MR imaging following endoscopic endonasal pituitary surgery

The value of immediate postoperative MR imaging following endoscopic endonasal pituitary surgery

Acta Neurochir (2014) 156:133–140

Although the value of early MR imaging has been justified for microscopic transphenoidal surgery, there is no literature evaluating immediate postoperative MR imaging following endoscopic endonasal resection of pituitary adenomas. We hypothesized that MRI of the pituitary gland performed on the first postoperative day is just as effective at detecting residual disease and/or reconstruction materials as the MRI at 3 months following surgery.

Methods We retrospectively evaluated 102 consecutive patients who underwent endoscopic endonasal surgery for presumed pituitary adenomas. Sixty-four patients met the inclusion criteria with immediate and 3 months MR imaging. Imaging was evaluated by two sets of observers. The following parameters were assessed: enhancement pattern of the pituitary gland, pituitary stalk, nodular enhancement (residual tumor) or linear enhancement (non-tumoral) and residual reconstruction/packing materials.

Results Gross total resection of the tumors with no cavernous sinus involvement was achieved in 49 out of 52 (94 %) patients. Eleven out of 12 remaining patients with cavernous sinus invasion had residual cavernous sinus component visible on both immediate and 3 month MR imaging. The pituitary gland, position of stalk, and nasoseptal flap could be identified on both post-operative MRIs in all patients. The sensitivity and specificity for residual tumor detection on immediate MRI was 100 % and 97.9 %, respectively. The kappa index evaluating interobserver agreement for identification of residual tumor and packing/reconstruction material on immediate MR was 0.83 and 0.72 indicating near perfect and substantial agreement, respectively.

Conclusion Immediate MR imaging performed following endoscopic endonasal resection of pituitary lesions provides accurate and reliable information regarding the presence of residual tumor compared to reconstruction and packing materials.

The Recesses of the Sellar Wall of the Sphenoid Sinus and Their Intracranial Relationships

The_Recesses_of_the_Sellar_Wall_of_the_Sphenoid

Neurosurgery 73[ONS Suppl 2]:ons117–ons131, 2013

The sellar wall of the sphenoid sinus and its recesses have been previously studied, but their intracranial relationships to the diaphragma sellae, tuberculum, clinoid segment of the internal carotid artery, chiasmatic sulcus, and middle clinoid process need further definition.

OBJECTIVE: To describe these intra- and extracranial relationships of the recesses in the anterior sellar wall.

METHODS: The middle clinoid was studied in 132 parasellar areas of dry crania. Thirtyeight parasellar areas of formalin-fixed/silicone-colored specimens were dissected. After transsphenoidal endoscopic exposure, the optic, carotid, and sellar prominences; lateral opticocarotid and tuberculum recesses; and caroticosellar and medial opticocarotid points were identified. High-speed drills opened 1-mm perforations at these points to allow study of intracranial relationships.

RESULTS: Two recesses and 2 junction points can be recognized in the sphenoid sinus: lateral opticocarotid and tuberculum recesses and medial opticocarotid and caroticosellar points. The lateral opticocarotid recess corresponds to the optic strut base, and the clinoid segment of the internal carotid artery is located medially. The diaphragma sellae attachment is at the level of the tuberculum recess, which in 50% of cases corresponds to the tuberculum. A middle clinoid in base or height greater than 1.5 mm is present in 21.1% and a caroticoclinoid ring in 3%. The middle clinoid is 1 mm inferior and lateral to the caroticosellar point and 4.7 mm inferior to the medial opticocarotid point.

CONCLUSION: An understanding of the intra- and extracranial relationships of the recesses of the sphenoid sinus will aid in accurately directing transsphenoidal approaches.