En-bloc Resection of A Giant Solid Hemangioblastoma of The Vermis
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.329537
Source of Support: None, Conflict of Interest: None
Keywords: En-bloc excision, giant hemangioblastoma, solid hemangioblastoma, suboccipital craniotomy
Surgical management of giant hemangioblastomas (HMB) is technically challenging. Most HMB have cystic or solid-cystic forms (70%–75%), which predominantly occur in the cerebellar hemispheres. In contrast, the solid variants are frequently present in the brainstem, cerebellar vermis, and spinal cord. The characteristics of solid tumors are similar to intracranial arteriovenous malformations., The piecemeal resection and internal decompression of the giant tumors are shown to have devastating intraoperative complications. Thus, the surgical principle of giant solid tumors requires proper planning, preoperative embolization, generous exposure, circumferential dissection, and en-bloc resection following microneurosurgical principles. The following article demonstrates the surgical technique of en-bloc resection of a giant solid variant of HMB from the cerebellar vermis.
[Figure 1], [Figure 2], [Figure 3]
The video in this article demonstrates the en-bloc excision of a solid variant of giant HMB by using a midline suboccipital craniotomy along with C1 laminectomy.
A 38-year-old male patient with no comorbidities presented with complaints of headache and vomiting for one year, imbalance during walking for 6 months, and dysphagia and hoarseness of voice for 2 months. He underwent a CSF diversion procedure in another hospital in view of obstructive hydrocephalus and was referred to our center for definitive surgery. Examination revealed left-sided cerebellar dysfunction, impaired cough and gag on both sides, tongue atrophy on the left side, without sensory-motor deficits. He was evaluated with a contrast-enhanced MRI, which showed a large heterogeneously enhancing solid lesion of size 46 × 33 × 40 mm3 with a central necrotic area in the posterior fossa with perilesional edema and multiple flow voids on T2-MR sequence. The patient also underwent contrast-enhanced computed tomography of chest and abdomen to rule out the presence of intraabdominal malignancy.
In view of the solid variant of giant HMB with extensive vascularity, preoperative embolization was performed; however, there was no significant reduction in the vascularity of the lesion. The patient underwent en-bloc resection within 24 h of embolization. The histopathology confirmed the radiological diagnosis. Postoperative MRI performed at three weeks after surgery showed no residual lesion with a small resolving hematoma.
With a radiological diagnosis of solid HMB probably arising from the vermis, the patient was counseled and planned for midline suboccipital craniotomy and excision of the tumor.
The patient was under general anesthesia, and appropriate neuroprotective measures were taken. A central venous access, an arterial line, and two large-bore peripheral venous lines were secured. Intraoperative neuromonitoring was set up to use motor evoked potentials, somatosensory evoked potentials, and lower cranial nerve monitoring. A cell saver kit was also set up during surgery for autologous transfusion.
The patient was positioned prone, with the neck slightly flexed and head fixed with a Mayfield clamp. A broad, generous midline suboccipital craniotomy was performed, extending superiorly to the transverse sinus and inferiorly to the foramen magnum. The posterior arch of C1 was also removed to tackle the inferior meningeal feeders arising from the vertebral artery. On craniotomy, dura was full and tense. Dura was opened in a Y-shaped manner; the inferior limb extended inferiorly till the lower end of the C1 arch. The two oblique limbs were extended superiorly till the inferior end of the transverse sinus. There were numerous dilated draining venous channels during the dural opening, and the bleeding from these veins was controlled using Liga clips. After durotomy, the brain was full and pulsatile. There was evidence of a large solid mass in the midline splaying the two cerebellar hemispheres with numerous dilated veins over the tumor. The arachnoid membrane over the tumor was dissected and the circumferential dissection around the tumor was done in all directions. There were multiple feeders from bilateral PICA, AICA, and SCA, which were identified and coagulated, and large dilated arterialized veins were coagulated and divided at the end of dissection. After dissection, the tumor was removed en-bloc and hemostasis was achieved. Lax duroplasty was performed with pericranium.
Video link: https://youtu.be/xTt9u17PcR8
Video timeline with audio transcript
0.06–1.26 min: A 38-year-old male patient presented with headache and vomiting for one year, imbalance during walking for six months, and hoarseness of voice for two months. He underwent a left-sided VPS in view of obstructive HCP at another hospital and was referred to our center for definitive surgery. Contrast-enhanced MRI showed a large heterogeneously enhancing solid lesion of size 4.6cms with central necrotic area in the vermis with perilesional edema and multiple large flow voids on T2-WI sequence. Arterial spin labelling (ASL) revealed a large area of hyper-perfusion suggestive of a highly vascular lesion. Angiogram revealed a highly vascular tumor with arterial feeders from left vertebral, anterior inferior cerebellar, right vertebral. Preoperative embolization performed could only partially reduce the vascularity.
1.26–1.50 min: The patient was positioned prone with the head fixed on a Mayfield head holder with neck flexion. A wide midline suboccipital craniotomy and C1 laminectomy was fashioned.
1.50–2.21 min: Dura was opened in a Y-shaped manner, with the vertical limb inferiorly extending till the superior border of the C2 vertebra and both the oblique limbs extending superiorly and laterally till the inferior border of transverse sinus. During the durotomy, there were multiple dilated draining venous channels, and the bleeding from these veins was controlled using Liga clips. After durotomy, tonsillar herniation was noted inferiorly below the C1 arch.
2.22–2.38 min: There was a large yellowish solid vascular mass present in the midline splaying both the cerebellar hemispheres. The arachnoid dissection was commenced on the superior aspect of the tumor and a small arterial feeder was identified, which was coagulated and cut.
2.38–3.00 min: The circumferential tumor dissection was performed beginning on the left side of the tumor. The tumor surface was coagulated to shrink and facilitate circumferential dissection around the tumor. The large veins were preserved during the initial stage of dissection.
3.03-3.14 min: An arterial feeder from the left PICA was identified, coagulated, and divided on the tumor surface.
3.15-3.35 min: The dissection was further performed around the tumor continuing superiorly on the left side. As seen, the tumor has lost its turgidity and has become supple and pale as a result of circumferential dissection and coagulation of the arterial feeders.
3.35–3.50 min: An arterial feeder from left SCA was identified and coagulated on the tumor surface, and the dissection was continued further toward the superior aspect.
3.50–4.20 min: Similarly, the tumor dissection was performed along the inferior part of the tumor.
4.21–4.32 min: This was followed by dissection along the inferolateral aspect on the right side.
4.32–4.58 min: A large dilated arterialized draining vein was identified on the tumor surface on the right lateral aspect, which was coagulated and divided.
4.58–5.09 min: After performing the circumferential dissection, ventral dissection from the vermis was performed and the arterial feeders on the tumor capsule were coagulated and cut.
5.09–5.41 min: The tumor was delivered en-bloc following complete dissection. In this step, it is not uncommon to encounter bleeding from the remaining tumor remanent, which can be controlled with coagulation and tumor removal.
5.41–6.14 min: The small residual component of the tumor in the inferior aspect of the tumor was removed.
6.14–6.21 min: Following complete resection of the tumor, meticulous hemostasis was achieved with coagulation and layering of FloSeal (a combination of gelatin and human thrombin). Watertight dural closure was achieved using a pericranial patch.
6.21–6.27 min: Bone flap was replaced and fixed using miniplate screws.
6.27–6.33 min: Postoperative CT showed a good operative cavity with minor bleed in the cavity.
6.33–6.45 min: The patient was electively ventilated for 48 h after surgery and was tracheostomized in view of impaired gag and cough reflex in the preoperative period. The patient was decannulated and discharged after 3 weeks.
Following surgery, the patient was tracheostomized in view of impaired gag due to lower cranial nerve paresis and hence was started on Ryles tube feeding. Postoperative CT showed a good cavity with small tumor bed hematoma, which did not require any intervention. The patient was decannulated after three weeks once the cough and gag reflex improved gradually. Contrast-enhanced MRI performed after one month of surgery showed no residual tumor with resolving hematoma.
Pearls and pitfalls
HMBs are benign neoplasms that are predominantly noted in adults, and the complete surgical removal is the goal of surgery. Approximately two-thirds of these tumors are cystic with hypervascular mural nodules. A solid variant of HMB is rare and is associated with an increased risk of massive intraoperative bleeding and postoperative complications. Owing to their AVM-like characteristics, giant solid subtypes are more technically challenging.
In our case, selective preoperative embolization of the feeding arteries was done to reduce vascularity, but there was no significant reduction of vascularity of the lesion. The role of embolization remains controversial owing to its associated risks, including bleeding, ischemia, and increased intracranial pressure., The indications of embolization should be decided on an individual basis and should be performed within one day or immediately before surgery by neuro-endovascular experts.
Owing to the improvements in the microsurgical techniques and a proper understanding of the tumor vascular pattern, en-bloc tumor resection can be safely achieved with minimal intraoperative bleeding and postoperative complications., The tumor-feeding arteries are often situated deep anteriorly on both sides of the tumor, whereas the draining veins are observed on the posterior surface of the tumor.
Solid giant-sized HMBs require preoperative embolization whenever feasible. However, when embolization is least effective, as in the case described here, en-bloc excision using standard microsurgical technique (without violating the tumor capsule) aids in safe removal of these difficult lesions.
Declaration of patient consent
Full and detailed consent from the patient/guardian has been taken. The patient's identity has been adequately anonymized. If anything related to the patient's identity is shown, adequate consent has been taken from the patient/relative/guardian. The journal will not be responsible for any medico-legal issues arising out of issues related to the patient's identity or any other matters arising from the public display of the video.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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