PMC10235621_01
Radiological evaluation of the multi-compartmental lesion preoperatively and postoperatively. (A-D) Preoperative axial (A), coronal (B, C), and sagittal (D) T1-weighted magnetic resonance images with gadolinium enhancement. (E-G) Preoperative tomography images of bone windows (E, F) and three-dimensional reconstruction (G) revealed no erosion of the middle cranial fossa base and truncation of the petrous apex on the left. (H-K) Postoperative axial (E), coronal (F, G), and sagittal (H) T1-weighted magnetic resonance images with gadolinium enhancement.
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Compression of the left temporal lobe and brainstem was present ( Figures 1A-D ). Computed tomographic scans revealed no erosion of the middle cranial fossa base and truncation of the petrous apex on the left ( Figures 1E-G ). Postoperatively, the patient had stable trigeminal neuropathy without any new neurological deficits, and imaging examinations indicated that gross total resection was achieved ( Figures 1H-K ).
Surgical setup for the hybrid operation. The painting shows the layout of our operating room and the lateral positioning of the patient. The inset figures indicate head positioning (left) and skin incisions (right).
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The endoscope monitor (Karl Storz) was placed in front of the patient, with the pneumatic arm holder placed on the contralateral bedside, while the microscope was placed at the head end ( Figure 2 ).
Surgical procedure of EF-SCITA approach for resection of posterior fossa tumor. (A) Skin incision for lateral suboccipital craniotomy (left) and subtemporal craniotomy (right). (B) Bone window for exposure of the transverse sinus and the inner edge of the sigmoid sinus. (C) Endoscopic explorations in the lateral supracerebellar-infratentorial space. (D) The exposure of posterior fossa tumor in the petroclincal region after tentorium incision. (E) Tumor resection in a piecemeal fashion. (F) The exposure of CN V and CN III after tumor resection. Cer., cerebellum; CN III, oculomotor nerve; CN IV, trochlear nerve; CN V, trigeminal nerve; SPV, superior petrosal vein; T, tumor; Temp., temporal lobe; Tent., tentorium cerebelli.
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A small straight retroauricular incision was first performed to obtain exposure of the lateral suboccipital region ( Figure 3A ). Then, the entire transverse sinus and the proximal part of the sigmoid sinus were revealed through suboccipital craniotomy ( Figure 3B ). The tentorium cerebelli was opened for better exposure of the tumor, with attention to CN IV protection ( Figures 3C, D ). The tumor was found to originate from the CN V and remain cephalad to the petrosal vein ( Figure 3D ). Then, the lesion was removed in a piecemeal fashion, with multiple adhesions involving the tentorial notch and cerebellum carefully dissected ( Figure 3E ). III residing in front of the lesion was identified. Importantly, the CN V that was displaced laterally and posteriorly into the plexiform layer was carefully separated from the tumor and preserved as intact as possible ( Figure 3F ).
Microsurgical subtemporal-interdural approach for exposure of middle fossa tumor and synchronous microsurgical and endoscopic resection of middle fossa tumor. (A) Middle fossa dural peeling toward the lateral edges of the oval and round foramina. (B) Detachment the periosteal dura from the meningeal dura of the temporal base for the exposure of Meckel cave. (C) Exposure of tumor within the Meckel cave beneath CN V fibers. (D) The separation of tumor from the wall of Meckel cave. (E) The microsurgical view showing tumor displacement into the porus trigeminus with the aid of cotton-pieces and curette (left) and synchronous endoscopic view indicating tumor extraction via the porus trigeminus in the supracerebellar space (right). (F) The microsurgical view (left) and synchronous endoscopic view (right) indicating explorations via a dissector for residual tumor toward Meckel cave through the porus trigeminus. CN V, trigeminal nerve; For., foramen; PT, porus trigeminus; T, tumor; V3, the mandibular nerve. The yellow circle indicates the boundary of the Meckel Cave. The asterisks indicate the dissector.
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Middle fossa dural peeling was performed epidurally to the lateral edges of the oval and round foramina ( Figure 4A ). Then, the periosteal dura was sharply detached from the meningeal dura of the temporal base to expose the MC ( Figure 4B ). The tumor covered with the plexiform portion of the CN V could be exposed by dissecting the fibers on the surface ( Figure 4C ). With gentle movements, the tumor margin was easily separated within the MC ( Figure 4D ). Figure 4E ). Finally, endoscopic explorations for residual tumor were permitted toward the MC through the PT under microscopic monitoring ( Figure 4F ).