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Open access

Peyton L. Nisson, Robert T. Wicks, Xiaochun Zhao, Whitney S. James, David Xu, and Peter Nakaji

Cavernous malformations of the brain are low-flow vascular lesions that have a propensity to hemorrhage. Extensive surgical approaches are often required for operative cure of deep-seated lesions. A 23-year-old female presented with a cavernous malformation of the left posterior insula with surrounding hematoma measuring up to 3 cm. A minimally invasive (mini-)pterional craniotomy with a transsylvian approach was selected. Endoscopic assistance was utilized to confirm complete resection of the lesion. The minipterional craniotomy is a minimally invasive approach that provides optimal exposure for sylvian fissure dissection and resection of many temporal and insular lesions.

The video can be found here: https://youtu.be/9z6_EhU6lxs.

Restricted access

Ali Tayebi Meybodi, Michael T. Lawton, Leandro Borba Moreira, Xiaochun Zhao, Michael J. Lang, Peter Nakaji, and Mark C. Preul

OBJECTIVE

Harvesting the occipital artery (OA) is challenging. The subcutaneous OA is usually found near the superior nuchal line and followed proximally, requiring a large incision and risking damage to the superficially located OA. The authors assessed the anatomical feasibility and safety of exposing the OA through a retromastoid-transmuscular approach.

METHODS

Using 10 cadaveric heads, 20 OAs were harvested though a 5-cm retroauricular incision placed 5 cm posterior to the external auditory meatus. The underlying muscle layers were sequentially cut and recorded before exposing the OA. Changes in the orientation of muscle fibers were used as a roadmap to expose the OA without damaging it.

RESULTS

The suboccipital segment of the OA was exposed without damage after incising two consecutive layers of muscles and their investing fasciae. These muscles displayed different fiber directions: the superficially located sternocleidomastoid muscle with vertically oriented fibers, and the underlying splenius capitis with anteroposteriorly (and mediolaterally) oriented fibers. The OA could be harvested along the entire length of the skin incision in all specimens. If needed, the incision can be extended proximally and/or distally to follow the OA and harvest greater lengths.

CONCLUSIONS

This transmuscular technique for identification of the OA is a reliable method and may facilitate exposure and protection of the OA during a retrosigmoid approach. This technique may obviate the need for larger incisions when planning a bypass to nearby arteries in the posterior circulation via a retrosigmoid craniotomy. Additionally, the small skin incision can be enlarged when a different craniotomy and/or bypass is planned or when a greater length of the OA is needed to be harvested.

Free access

Robert T. Wicks, Xiaochun Zhao, Douglas A. Hardesty, Brandon D. Liebelt, and Peter Nakaji

Ethmoidal dural arteriovenous fistulas (DAVFs) have a near-universal association with cortical venous drainage and a malignant clinical course. Endovascular treatment options are often limited due to the high frequency of ophthalmic artery ethmoidal supply. A 64-year-old gentleman presented with syncope and was found to have a right ethmoidal DAVF. Rather than the traditional bicoronal craniotomy, an endoscope-assisted mini-pterional approach for clip ligation is demonstrated. The mini-pterional craniotomy allows a minimally invasive approach to ethmoidal DAVF via a lateral trajectory. The endoscope can help achieve full visualization in the narrow corridor.

The video can be found here: https://youtu.be/ZroXp-T35DI.

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Colin J. Przybylowski, Benjamin K. Hendricks, Fabio A. Frisoli, Xiaochun Zhao, Claudio Cavallo, Leandro Borba Moreira, Sirin Gandhi, Nader Sanai, Kaith K. Almefty, Michael T. Lawton, and Andrew S. Little

OBJECTIVE

Recently, the prognostic value of the Simpson resection grading scale has been called into question for modern meningioma surgery. In this study, the authors analyzed the relationship between Simpson resection grade and meningioma recurrence in their institutional experience.

METHODS

This study is a retrospective review of all patients who underwent resection of a WHO grade I intracranial meningioma at the authors’ institution from 2007 to 2017. Binary logistic regression analysis was used to assess for predictors of Simpson grade IV resection and postoperative neurological morbidity. Cox multivariate analysis was used to assess for predictors of tumor recurrence. Kaplan-Meier analysis and log-rank tests were used to assess and compare recurrence-free survival (RFS) of Simpson resection grades, respectively.

RESULTS

A total of 492 patients with evaluable data were included for analysis, including 394 women (80.1%) and 98 men (19.9%) with a mean (SD) age of 58.7 (12.8) years. The tumors were most commonly located at the skull base (n = 302; 61.4%) or the convexity/parasagittal region (n = 139; 28.3%). The median (IQR) tumor volume was 6.8 (14.3) cm3. Simpson grade I, II, III, or IV resection was achieved in 105 (21.3%), 155 (31.5%), 52 (10.6%), and 180 (36.6%) patients, respectively. Sixty-three of 180 patients (35.0%) with Simpson grade IV resection were treated with adjuvant radiosurgery. In the multivariate analysis, increasing largest tumor dimension (p < 0.01) and sinus invasion (p < 0.01) predicted Simpson grade IV resection, whereas skull base location predicted neurological morbidity (p = 0.02). Tumor recurrence occurred in 63 patients (12.8%) at a median (IQR) of 36 (40.3) months from surgery. Simpson grade I resection resulted in superior RFS compared with Simpson grade II resection (p = 0.02), Simpson grade III resection (p = 0.01), and Simpson grade IV resection with adjuvant radiosurgery (p = 0.01) or without adjuvant radiosurgery (p < 0.01). In the multivariate analysis, Simpson grade I resection was independently associated with no tumor recurrence (p = 0.04). Simpson grade II and III resections resulted in superior RFS compared with Simpson grade IV resection without adjuvant radiosurgery (p < 0.01) but similar RFS compared with Simpson grade IV resection with adjuvant radiosurgery (p = 0.82). Simpson grade IV resection with adjuvant radiosurgery resulted in superior RFS compared with Simpson grade IV resection without adjuvant radiosurgery (p < 0.01).

CONCLUSIONS

The Simpson resection grading scale continues to hold substantial prognostic value in the modern neurosurgical era. When feasible, Simpson grade I resection should remain the goal of intracranial meningioma surgery. Simpson grade IV resection with adjuvant radiosurgery resulted in similar RFS compared with Simpson grade II and III resections.

Open access

Xiaochun Zhao, Robert T. Wicks, Evgenii Belykh, Colin J. Przybylowski, Mohamed A. Labib, and Peter Nakaji

Neurocysticercosis is primarily managed with anthelminthic, antiepileptic, and corticosteroid therapies. Surgical removal of the larval cyst is indicated when associated mass effect causes neurological symptoms, as demonstrated in two cases. Cyst resection was achieved via the far lateral approach for a cervicomedullary cyst in one patient and via the subtemporal approach for a mesencephalic cyst in another. The cyst wall should be kept intact, when possible, to avoid dissemination of the inflammation-evoking contents. As the contents are usually semisolid and can be removed via suction, it is not necessary to remove the gliotic capsule or adherent portions of the cyst wall in highly eloquent locations.

The video can be found here: https://youtu.be/GqbaJu5sy1o.

Restricted access

Xiaochun Zhao, Ali Tayebi Meybodi, Mohamed A. Labib, Sirin Gandhi, Evgenii Belykh, Komal Naeem, Mark C. Preul, Peter Nakaji, and Michael T. Lawton

OBJECTIVE

Aneurysms that arise on the medial surface of the paraclinoid segment of the internal carotid artery (ICA) are surgically challenging. The contralateral interoptic trajectory, which uses the space between the optic nerves, can partially expose the medial surface of the paraclinoid ICA. In this study, the authors quantitatively measure the area of the medial ICA accessible through the interoptic triangle and propose a potential patient-selection algorithm that is based on preoperative measurements on angiographic imaging.

METHODS

The contralateral interoptic trajectory was studied on 10 sides of 5 cadaveric heads, through which the medial paraclinoid ICA was identified. The falciform ligament medial to the contralateral optic canal was incised, the contralateral optic nerve was gently elevated, and the medial surface of the paraclinoid ICA was inspected via different viewing angles to obtain maximal exposure. The accessible area on the carotid artery was outlined. The distance from the distal dural ring (DDR) to the proximal and distal borders of this accessible area was measured. The superior and inferior borders were measured using the clockface method relative to a vertical line on the coronal plane. To validate these parameters, preoperative measurements and intraoperative findings were reviewed in 8 clinical cases.

RESULTS

In the sagittal plane, the mean (SD) distances from the DDR to the proximal and distal ends of the accessible area on the paraclinoid ICA were 2.5 (1.52) mm and 8.4 (2.32) mm, respectively. In the coronal plane, the mean (SD) angles of the superior and inferior ends of the accessible area relative to a vertical line were 21.7° (14.84°) and 130.9° (12.75°), respectively. Six (75%) of 8 clinical cases were consistent with the proposed patient-selection algorithm.

CONCLUSIONS

The contralateral interoptic approach is a feasible route to access aneurysms that arise from the medial paraclinoid ICA. An aneurysm can be safely clipped via the contralateral interoptic trajectory if 1) both proximal and distal borders of the aneurysm neck are 2.5–8.4 mm distal to the DDR, and 2) at least one border of the aneurysm neck on the coronal clockface is 21.7°–130.9° medial to the vertical line.

Open access

Jianping Song, Peiliang Li, Yanlong Tian, Xiaochun Zhao, Xiaowen Wang, and Wei Zhu

The large intracranial hemangioblastoma is a top surgical challenge due to its nature of invading brain parenchyma, tight adherence to the pia, and rich blood supply from numerous pial vasculatures and arteries in the proximity. If the brainstem is involved in the lesion, the surgery will be more dangerous because of potential brainstem impingement. In this illustrative video, we present a case of a 54-year-old male with a large hemangioblastoma at the mesencephalic-cerebellar region, which was successfully treated by hybrid endovascular embolization and microsurgery via an occipital interhemispheric transtentorial approach with minimal intraoperative blood loss and a favorable outcome.

The video can be found here: https://youtu.be/pJqFhY_Zhv0.

Restricted access

Mohamed A. Labib, Evgenii Belykh, Claudio Cavallo, Xiaochun Zhao, Daniel M. Prevedello, Ricardo L. Carrau, Andrew S. Little, Mauro A. T. Ferreira, Mark C. Preul, A. Samy Youssef, and Peter Nakaji

OBJECTIVE

The ventral jugular foramen and the infrapetrous region are difficult to access through conventional lateral and posterolateral approaches. Endoscopic endonasal approaches to this region are obstructed by the eustachian tube (ET). This study presents a novel strategy for mobilizing the ET while preserving its integrity. Qualitative and quantitative comparisons with previous ET management paradigms are also presented.

METHODS

Ten dry skulls were analyzed. Four ET management strategies were sequentially performed on a total of 6 sides of cadaveric head specimens. Four measurement groups were generated: in group A, the ET was intact and not mobilized; in group B, the ET was mobilized inferolaterally; in group C, the ET underwent anterolateral mobilization; and in group D, the ET was resected. ET range of mobilization, surgical exposure area, and surgical freedom were measured and compared among the groups.

RESULTS

Wide exposure of the infrapetrous region and jugular foramen was achieved by removing the pterygoid process, unroofing the cartilaginous ET up to the level of the posterior aspect of the foramen ovale, and detaching the ET from the skull base and soft palate. Anterolateral mobilization of the ET facilitated significantly more retraction (a 126% increase) of the ET than inferolateral mobilization (mean ± SD: 20.8 ± 11.2 mm vs 9.2 ± 3.6 mm [p = 0.02]). Compared with group A, groups C and D had enhanced surgical exposure (142.5% [1176.9 ± 935.7 mm2] and 155.9% [1242.0 ± 1096.2 mm2], respectively, vs 485.4 ± 377.6 mm2 for group A [both p = 0.02]). Furthermore, group C had a significantly larger surgical exposure area than group B (p = 0.02). No statistically significant difference was found between the area of exposure obtained by ET removal and anterolateral mobilization. Anterolateral mobilization of the ET resulted in a 39.5% increase in surgical freedom toward the exocranial jugular foramen compared with that obtained through inferolateral mobilization of the ET (67.2° ± 20.5° vs 48.1° ± 6.7° [p = 0.047]) and a 65.4% increase compared with that afforded by an intact ET position (67.2° ± 20.5° vs 40.6° ± 14.3° [p = 0.03]).

CONCLUSIONS

Anterolateral mobilization of the ET provides excellent access to the ventral jugular foramen and infrapetrous region. The surgical exposure obtained is superior to that achieved with other ET management strategies and is comparable to that obtained by ET resection.

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Colin J. Przybylowski, Xiaochun Zhao, Jacob F. Baranoski, Leandro Borba Moreira, Sirin Gandhi, Kristina M. Chapple, Kaith K. Almefty, Nader Sanai, Andrew F. Ducruet, Felipe C. Albuquerque, Andrew S. Little, and Peter Nakaji

OBJECTIVE

The controversy continues over the clinical utility of preoperative embolization for reducing tumor vascularity of intracranial meningiomas prior to resection. Previous studies comparing embolization and nonembolization patients have not controlled for detailed tumor parameters before assessing outcomes.

METHODS

The authors reviewed the cases of all patients who underwent resection of a WHO grade I intracranial meningioma at their institution from 2008 to 2016. Propensity score matching was used to generate embolization and nonembolization cohorts of 52 patients each, and a retrospective review of clinical and radiological outcomes was performed.

RESULTS

In total, 52 consecutive patients who underwent embolization (mean follow-up 34.8 ± 31.5 months) were compared to 52 patients who did not undergo embolization (mean follow-up 32.8 ± 28.7 months; p = 0.63). Variables controlled for included patient age (p = 0.82), tumor laterality (p > 0.99), tumor location (p > 0.99), tumor diameter (p = 0.07), tumor invasion into a major dural sinus (p > 0.99), and tumor encasement around the internal carotid artery or middle cerebral artery (p > 0.99). The embolization and nonembolization cohorts did not differ in terms of estimated blood loss during surgery (660.4 ± 637.1 ml vs 509.2 ± 422.0 ml; p = 0.17), Simpson grade IV resection (32.7% vs 25.0%; p = 0.39), perioperative procedural complications (26.9% vs 19.2%; p = 0.35), development of permanent new neurological deficits (5.8% vs 7.7%; p = 0.70), or favorable modified Rankin Scale (mRS) score (a score of 0–2) at last follow-up (96.0% vs 92.3%; p = 0.43), respectively. When comparing the final mRS score to the preoperative mRS score, patients in the embolization group were more likely than patients in the nonembolization group to have an improvement in mRS score (50.0% vs 28.8%; p = 0.03).

CONCLUSIONS

After controlling for patient age, tumor size, tumor laterality, tumor location, tumor invasion into a major dural sinus, and tumor encasement of the internal carotid artery or middle cerebral artery, preoperative meningioma embolization intended to decrease tumor vascularity did not improve the surgical outcomes of patients with WHO grade I intracranial meningiomas, but it did lead to a greater chance of clinical improvement compared to patients not treated with embolization.

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Qing Sun, Xiaochun Zhao, Sirin Gandhi, Ali Tayebi Meybodi, Evgenii Belykh, Daniel Valli, Claudio Cavallo, Leandro Borba Moreira, Peter Nakaji, Michael T. Lawton, and Mark C. Preul

OBJECTIVE

The cisternal pulvinar is a challenging location for neurosurgery. Four approaches for reaching the pulvinar without cortical transgression are the ipsilateral supracerebellar infratentorial (iSCIT), contralateral supracerebellar infratentorial (cSCIT), ipsilateral occipital transtentorial (iOCTT), and contralateral occipital transtentorial/falcine (cOCTF) approaches. This study quantitatively compared these approaches in terms of surgical exposure and maneuverability.

METHODS

Each of the 4 approaches was performed in 4 cadaveric heads (8 specimens in total). A 6-sided anatomical polygonal region was configured over the cisternal pulvinar, defined by 6 reachable anatomical points in different vectors. Multiple polygons were subsequently formed to calculate the areas of exposure. The surgical freedom of each approach was calculated as the maximum allowable working area at the proximal end of a probe, with the distal end fixed at the posterior pole of the pulvinar. Areas of exposure, surgical freedom, and the working distance (surgical depth) of all approaches were compared.

RESULTS

No significant difference was found among the 4 different approaches with regard to the surgical depth, surgical freedom, or medial exposure area of the pulvinar. In the pairwise comparison, the cSCIT approach provided a significantly larger lateral exposure (39 ± 9.8 mm2) than iSCIT (19 ± 10.3 mm2, p < 0.01), iOCTT (19 ± 8.2 mm2, p < 0.01), and cOCTF (28 ± 7.3 mm2, p = 0.02) approaches. The total exposure area with a cSCIT approach (75 ± 23.1 mm2) was significantly larger than with iOCTT (43 ± 16.4 mm2, p < 0.01) and iSCIT (40 ± 20.2 mm2, p = 0.01) approaches (pairwise, p ≤ 0.01).

CONCLUSIONS

The cSCIT approach is preferable among the 4 compared approaches, demonstrating better exposure to the cisternal pulvinar than ipsilateral approaches and a larger lateral exposure than the cOCTF approach. Both contralateral approaches described (cSCIT and cOCTF) provided enhanced lateral exposure to the pulvinar, while the cOCTF provided a larger exposure to the lateral portion of the pulvinar than the iOCTT. Medial exposure and maneuverability did not differ among the approaches. A short tentorium may negatively impact an ipsilateral approach because the cingulate isthmus and parahippocampal gyrus tend to protrude, in which case they can obstruct access to the cisternal pulvinar ipsilaterally.