Is less always better? Keyhole and standard subtemporal approaches: evaluation of temporal lobe retraction and surgical volume with and without zygomatic osteotomy in a cadaveric model

Exposure region of the Kawase approach and its correlation with skull base anatomy: An evaluation with digital models

The Kawase approach is one of the most used trajectories in skull base surgery. The exposure range of the approach and its correlation with skull base anatomy still demand more exploration. With the help of digital rebuilding, analysis, and measurement, we evaluated the exposure range of the Kawase and extended Kawase approaches and analyzed the correlation between the exposure range and the variants of the petrosal and clival anatomy. The finding of the study demonstrated that compared to the sub-temporal approach, the Kawase approach and the extended Kawase approach significantly added the exposure range in the upper, middle, and partial inferior regions of the clivus. The gains in the exposure volume and area are more when the manipulation angle is less than 135°.

Scalp complications of craniofacial surgery: classification, prevention, and initial approach: an updated review

Background

Scalp complications in craniofacial surgeries can increase morbidity and mortality. Given the inelastic characteristics of the scalp, these surgeries can be challenging, and multiple complications can arise. The literature on craniofacial surgery is extensive. However, few articles address scalp complications, associated factors, and prevention. This study aims to identify and classify scalp complications in craniofacial surgery and describe associated risk factors, general preventive measures, and an initial therapeutic approach.

Methods

We conducted a literature search in PubMed, Scopus, Cochrane Library, and LILACS to review the scalp complications in craniofacial surgery. The studies selected included retrospective case series, narrative reviews, systematic reviews, and cadaveric anatomic studies. We completed the search with book chapters and specific topic reviews.

Results

We screened a total of 124 sources and selected 35 items for inclusion in this review. Based on the updated review, we categorized scalp complications into wound defects, soft tissue contour irregularities, neurovascular defects, and infection. We discuss the main characteristics, risk factors, preventive measures, and initial management of these complications.

Conclusions

For craniofacial surgery, understanding the surgical anatomy, identifying risk factors, adequate surgical planning, and interdisciplinary cooperation between neurosurgeons, plastic surgeons, and the interdisciplinary team are essential to prevent and treat scalp complications.

Level of evidence: Not ratable

Endoscopic transorbital approach to the cavernous sinus: Cadaveric anatomy study and clinical application (‡SevEN-009)

Objective

Cavernous sinus (CS) invasion is frequently encountered in the management of skull base tumors. Surgical treatment of tumors in the CS is technically demanding, and selection of an optimal surgical approach is critical for maximal tumor removal and patient safety. We aimed to evaluate the feasibility of an endoscopic transorbital approach (ETOA) to the CS based on a cadaveric study.

Methods

Five cadaveric heads were used for dissection under the ETOA in the comparison with the endoscopic endonasal approach (EEA) and the microscopic transcranial approach (TCA). The CS was exposed, accessed, and explored, first using the ETOA, followed by the EEA and TCA. A dedicated endoscopic system aided by neuronavigation guidance was used for the procedures. During the ETOA, neurovascular structures inside the CS were approached through different surgical triangles.

Results

After completing the ETOA with interdural dissection, the lateral wall of the CS was fully exposed. The lateral and posterior compartments of the CS, of which accessibility is greatly limited under the EEA, were effectively approached and explored under the ETOA. The anteromedial triangle was the largest window via which most of the lateral compartment was freely approached. The internal carotid artery and abducens nerve were also observed through the anteromedial triangle and just behind V1. During the ETOA, the approaching view through the supratrochlear and infratrochlear triangles was more directed towards the posterior compartment. After validation of the feasibility and safety based on the cadaveric study, ETOA was successfully performed in a patient with a pituitary adenoma with extensive CS invasion.

Conclusions

Based on the cadaveric study, we demonstrated that the lateral CS wall was reliably accessed under the ETOA. The lateral and posterior compartments of the CS were effectively explored via surgical triangles under the ETOA. ETOA provides a unique and valuable surgical route to the CS with a promising synergy when used with EEA and TCA. Our experience with a clinical case convinces us of the efficacy of the ETOA during surgical management of skull base tumors with CS-invasion.

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

A case of aphasia due to temporobasal edema: Contemporary models of language anatomy are clinically relevant

Background:

Understanding the anatomy of language in the human brain is crucial for neurosurgical decision making and complication avoidance. The traditional anatomical models of human language, relying on relatively simple and rigid concepts of brain connectivity, cannot explain all clinical observations. The clinical case reported here illustrates the relevance of more recent concepts of language networks involving white matter tracts and their connections.

Case Description:

Postoperative edema of the ventral occipitotemporal cortex, where modern network models locate a crucial language hub, resulted in transient severe aphasia after a subtemporal approach. Both verbal comprehension and expression were lost. The resolution of edema was associated with complete recovery from phonetic and semantic dysfunction.

Conclusion:

Complete aphasia due to a functional disturbance remote from the areas of Broca and Wernicke could be explained by contemporary neuroanatomical concepts of white matter connectivity. Knowledge of network-based models is relevant in brain surgery complication avoidance.

The Subtemporal Approach to the Lateral Midbrain with and without Zygomatic Osteotomy: An Anatomical Study

The subtemporal approach provides a narrow operative corridor to the crus cerebrum and adjacent structures of the crural, interpeduncular, and ambient cistern. Addition of a zygomatic osteotomy widens this narrow corridor and spares retraction of the temporal lobe. We investigate and compare the morphometric parameters of the subtemporal approach with versus without zygomatic osteotomy. On each side of four cadaveric heads, a temporal craniotomy was performed to gain access to the crus cerebrum and adjacent subarachnoid cisterns using a subtemporal approach. Operative corridor width and corridor working angle were measured with and without brain retraction on each specimen side. Next, a zygomatic osteotomy was performed followed by full downward reflection of the temporalis muscle and further drilling of the squamous part of the temporal bone. Lastly, operative corridor width and corridor working angle were measured again for comparison. The subtemporal operating corridor was (mean/SD): 5.8/2.6 mm without retraction, 11.4/4.3 mm with retraction, and 13.5/6.5° working angle. After addition of a zygomatic osteotomy, the operative corridor was 8/9.2/4.3 mm without retraction, 14.7/4.5 mm with retraction, 31.8/3.1° working angle. Zygomatic osteotomy significantly increased the operative corridor working angle of the subtemporal approach. Furthermore, we demonstrate a direct approach into the interpeduncular fossa. Clin. Anat. 32:710-714, 2019. © 2019 Wiley Periodicals, Inc.

Indications and Safety of the Zygomatic Osteotomy in Middle Cranial Fossa Surgery: A Retrospective Cohort Review

Background  Zygomatic osteotomy, an adjunct to middle cranial fossa (MCF) surgical approaches, improves the superior-inferior angle of approach and minimizes temporal lobe retraction. However, a decision-making algorithm for selective use of the zygomatic osteotomy and the impact of the zygomatic osteotomy on surgical complications have not been well documented. Objective  We described an algorithm for deciding whether to use a zygomatic osteotomy in MCF surgery and evaluated complications associated with a zygomatic osteotomy. Methods  A retrospective review of MCF cases over 11 years at our academic tertiary referral center was conducted. Demographic variables, tumor characteristics, surgical details, and postoperative complications were extracted. Results  Of the 87 patients included, 15 (17%) received a zygomatic osteotomy. Surgical trajectory oriented from anterior to posterior (A-P) was significantly correlated with the use of the zygomatic osteotomy. Among the cases approached from A-P, we found (receiver-operating characteristic curve) that the cut-off tumor size that predicted a zygomatic osteotomy was 30 mm. Of the 87 cases included, 15 patients had a complication. The multivariate logistic regression model failed to reveal any significant correlation between complications and zygomatic osteotomies. Conclusions  We found that the most important factor determining the use of a zygomatic osteotomy was anticipated trajectory. A-P approaches were most highly correlated with zygomatic osteotomy. Within those cases, a lesion size cut-off of 30 mm was the secondary predicting factor of zygomatic osteotomy use. The odds of suffering a surgical complication were not significantly increased by use of zygomatic osteotomy.

Less is more: Parahippocampal resection or endoscopic assistance in ambient cistern surgery? Qualitative and quantitative assessment of subtemporal approach

The ambient cistern is an arachnoid complex that extends from the crural cistern to lateral border of cerebral colliculi. The subtemporal approach has been recognized as the best access to reach pathologies in the ambient cistern, however many disadvantages exist. The present work aims to analyze quantitatively the area of exposure provided by the subtemporal access. The objective is to evaluate if there are advantages of using the neuroendoscope in conventional subtemporal access when compared to the subtemporal access with resection of the parahippocampal gyrus. A subtemporal approach was performed in six brain hemispheres. Qualitative and quantitative analyses were made. The linear exposition of the vascular structures and the surgical exposure area were evaluated. The linear exposure to the posterior cerebral artery was 5.95 for subtemporal access (ST) and 13.6 for subtemporal access with resection of the parahippocampal gyrus (STh) (p = 0.019). The total exposure area was 104.8 mm² for ST and 210.5 for STh (p = 0.0001). Regarding endoscope assistance the medial area, ST was 81.0 mm², and STend was 176.2 mm² (p = 0.038). For the total area of exposure, we obtained a value of 210.5 mm² for ST and a value of 391.3 mm² for STend (p = 0.041). In conventional subtemporal access, the use of the neuroendoscopes avoids the need for resection of the parahippocampal gyrus for better visualization of the ambient cistern structures.

Modified Orbitozygomatic Approach without Orbital Roof Removal for Middle Fossa Lesions

Objective

The purpose of the present study was to describe an OrBitoZygomatic (OBZ) surgical variant that implies the drilling of the orbital roof and lateral wall of the orbit without orbitotomy.

Methods

Design : cross-sectional study. Between January 2010 and December 2014, 18 patients with middle fossa lesions underwent the previously mentioned OBZ surgical variant. Gender, age, histopathological diagnosis, complications, and percentage of resection were registered. The detailed surgical technique is described.

Results

Of the 18 cases listed in the study, nine were males and nine females. Seventeen cases (94.5%) were diagnosed as primary tumoral lesions, one case (5.5%) presented with metastasis of a carcinoma, and an additional one had a fibrous dysplasia. Age ranged between 27 and 73 years. Early complications were developed in four cases, but all of these were completely resolved. None developed enophthalmos.

Conclusion

The present study illustrates a novel surgical OBZ approach that allows for the performance of a simpler and faster procedure with fewer complications, and without increasing surgical time or cerebral manipulation, for reaching lesions of the middle fossa. Thorough knowledge of the anatomy and surgical technique is essential for successful completion of the procedure.