A pitfall in the interhemispheric translamina terminalis approach for the removal of a craniopharyngioma. Significance of preserving draining veins. Part I. Clinical study

Craniopharyngioma in Pediatrics and Adults

Craniopharyngiomas are rare malignancies of dysembryogenic origin, involving the sellar and parasellar areas. These low-grade, epithelial tumors account for two main histological patterns (adamantinomatous craniopharyngioma and papillary craniopharyngioma), which differ in epidemiology, pathogenesis, and histomorphological appearance. Adamantinomatous craniopharyngiomas typically show a bimodal age distribution (5-15 years and 45-60 years), while papillary craniopharyngiomas are limited to adult patients, especially in the fifth and sixth decades of life. Recently, craniopharyngioma histological subtypes have been demonstrated to harbor distinct biomolecular signatures. Somatic mutations in CTNNB1 gene encoding β-catenin have been exclusively detected in adamantinomatous craniopharyngiomas, which predominantly manifest as cystic lesions, while papillary craniopharyngiomas are driven by BRAF V600E mutations in up to 95% of cases and are typically solid masses. Despite the benign histological nature (grade I according to the World Health Organization classification), craniopharyngiomas may heavily affect long-term survival and quality of life, due to their growth pattern in a critical region for the presence of eloquent neurovascular structures and possible neurological sequelae following their treatment. Clinical manifestations are mostly related to the involvement of hypothalamic-pituitary axis, optic pathways, ventricular system, and major blood vessels of the circle of Willis. Symptoms and signs referable to intracranial hypertension, visual disturbance, and endocrine deficiencies should promptly raise the clinical suspicion for sellar and suprasellar pathologies, advocating further neuroimaging investigations, especially brain MRI. The optimal therapeutic management of craniopharyngiomas is still a matter of debate. Over the last decades, the surgical strategy for craniopharyngiomas, especially in younger patients, has shifted from the aggressive attempt of radical resection to a more conservative and individualized approach via a planned subtotal resection followed by adjuvant radiotherapy, aimed at preserving functional outcomes and minimizing surgery-related morbidity. Whenever gross total removal is not safely feasible, adjuvant radiotherapy (RT) and stereotactic radiosurgery (SRS) have gained an increasingly important role to manage tumor residual or recurrence. The role of intracavitary therapies, including antineoplastic drugs or sealed radioactive sources, is predominantly limited to monocystic craniopharyngiomas as secondary therapeutic option. Novel findings in genetic profiling of craniopharyngiomas have unfold new scenarios in the development of targeted therapies based on brand-new biomolecular markers, advancing the hypothesis of introducing neoadjuvant chemotherapy regimens in order to reduce tumor burden prior to resection. Indeed, the rarity of these neoplasms requires a multispecialty approach involving an expert team of endocrinologists, neurosurgeons, neuro-ophthalmologists, neuroradiologists, radiotherapists, and neuro-oncologists, in order to pursue a significant impact on postoperative outcomes and long-term prognosis.

Case report and literature review: Resection of retroinfundibular craniopharyngioma via endoscopic far-lateral supracerebellar infratentorial approach

Introduction

The management of retroinfundibular craniopharyngioma (CP) remains the ultimate challenge for both transsphenoidal and open transcranial surgery because of their anatomical location and proximity to vital neurovascular structures. In this report, we aim to describe the technique and feasibility of a novel approach, the purely endoscopic far-lateral supracerebellar infratentorial approach (EF-SCITA), for resection of retroinfundibular CP.

Case description

A 63-year-old women presented with progressive visual disturbance, polyuria, and spiritlessness of a 3-month duration. Imaging studies revealed a typical retroinfundibular CP containing solid and cystic components with calcification, which extended inferiorly in front of the brainstem and upward into the third ventricle. The EF-SCITA approach was attempted for resection of the tumor. During surgery, lateral prone positioning with upper flexion of the head and early CSF release allowed for download retraction of the cerebellum. This, in combination with tentorium incision, created a working corridor toward retrosellar and suprasellar spaces. This approach required working between neurovascular structures in the crural cistern, with tumor removal permitted in supra-oculomotor and infra-oculomotor spaces. After aspiration of the fluid contents through the supra-oculomotor triangle, the solid lesion was found tightly adhering to the distal part of the pituitary stalk, and subtotal resection was achieved for maintaining the integrity of pituitary function. In the immediate postoperative period, the patients exhibited oculomotor paralysis and was discharged with hormonal replacement therapy three weeks after operation. At her three-month follow-up appointment, she reported obvious vision improvement. Physical examinations showed partial alleviation of oculomotor paralysis. Pathological analyses confirmed the diagnosis of papillary CP.

Discussion

The purely EF-SCITA approach combines the advantages of both the posterolateral approach and endoscopic technique, which offers access to retrosellar and suprasellar spaces with seemingly low risks of postoperative morbidity. It would be a safe and effective alternative for the treatment of retroinfundibular CP, especially those with lateral extension to the temporal lobe or posterolateral extension to the petroclival region. Further observational studies in a larger cohort are urgently needed to assess the long-term efficacy of this minimal access approach.

The interhemispheric approach in children: our experience and review of the literature

OBJECTIVE

The interhemispheric approach (IA) has been extensively described for treating pathologies located at the lateral or third ventricle, pineal region, and periventricular locations. While these anatomical locations are the target of many pediatric pathologies, very few series have analyzed the morbidity and outcome of the IA in children. The aim of this study is to describe our experience using the IA in children, emphasizing the approach-related morbidity.

METHODS

Twenty-six patients underwent 28 procedures using the IA between the years 2012 and 2016. Data for these patients was retrospectively analyzed. Surgical and approach-related morbidity were collected and analyzed.

RESULTS

The mean age of the cohort was 10.1 ± 4.2 years and included 15 females (57.7%). Approach-related morbidity occurred following eight surgeries (28.6%; seven with anterior IA and one with posterior IA), including two pseudomeningoceles (7.1%), three persistent subdural effusions (10.7%), of which two were locally drained and one required subduro-peritoneal shunting, one epidural bleed (3.6%) which resolved spontaneously, and two infections (3.6%) treated with antibiotics. Cerebrospinal fluid leaks, supplementary motor area syndrome, seizures, and subdural hematomas did not occur in any of the patients. None of the approach-related complications led to permanent morbidity or to mortality.

CONCLUSION

The IA for lesions in and around the ventricular system is feasible and associated with a low permanent complication rate. When choosing this approach, the morbidity, although rarely permanent, should be considered.

Technique for rerouting a bridging vein that hinders the anterior interhemispheric approach: a technical note

BACKGROUND

The frontal bridging vein, which is the venous drainage route of the frontal cortex into the superior sagittal sinus (SSS), sometimes poses an obstacle in the anterior interhemispheric approach during surgery for anterior cerebral artery aneurysms. Although severe complications including venous infarction or edema due to damage to the bridging vein are well known, only a few reports have discussed how to avoid venous injury when we must sacrifice the bridging vein to obtain an appropriate surgical field. This report describes a microvascular technique performed in two patients who underwent rerouting of the bridging vein to obtain an appropriate anterior interhemispheric surgical corridor to treat a ruptured anterior cerebral artery aneurysm. The hindering bridging vein was resected from the entrance to the SSS and anastomosed toward the adjacent cortical vein.

METHODS

A 65-year-old male and a 43-year-old male were admitted to our hospital for sudden headache. Computed tomography, magnetic resonance angiogram, or digital subtraction angiography demonstrated a subarachnoid hemorrhage and an anterior cerebral artery aneurysm in both patients. In both cases, a relatively robust bridging vein, which appeared problematic to sacrifice, was draining into the SSS, resulting in a limited surgical corridor. Thus, we performed cortical vein reconstruction, and the aneurysms were successfully clipped under a wider surgical view.

RESULTS

We confirmed completed clipping without postoperative venous complications. One patient demonstrated patency of reconstructed venous flow by digital subtraction angiography. No apparent cognitive impairment was seen in either patient.

CONCLUSIONS

This technique may be useful for obtaining an appropriate surgical corridor when the frontal bridging vein may be damaged.

Resection of tumors of the third ventricle involving the hypothalamus: effects on body mass index using a dedicated surgical approach

Resection of large lesions growing into the third ventricle is considered nowadays still a demanding surgery, due to the high risk of severe endocrine and neurological complications. Some neurosurgical approaches were considered in the past the procedures of choice to access the third ventricle, however they were burden by endocrine and neurological consequences, like memory loss and epilepsy. We report here the endocrine and functional results in a series of patients operated with a recently developed approach specifically tailored for the resection of large lesions growing into the third ventricle. Authors conducted a retrospective analysis on 10 patients, operated between 2011 and 2012, for the resection of large tumors growing into the third ventricle. Total resection was achieved in all patients. No perioperative deaths were recorded and all patients were alive after the follow-up. One year after surgery 8/10 patients had an excellent outcome with a Karnofsky Performance Status of 100 and a Glasgow Outcome score of 5, with 8 patients experiencing an improvement of the Body Mass Index. Modern neurosurgery allows a safe and effective treatment of large lesions growing into the third ventricle with a postoperative good functional status.

Absence of the superior petrosal veins and sinus: Surgical considerations

Background:

The superior petrosal vein, one of the most constant and largest drainage pathways in the posterior fossa, may result in complications if occluded. This study calls attention to a unique variant in which the superior petrosal veins and sinus were absent unilaterally, and the venous drainage was through the galenic and tentorial drainage groups.

Methods:

This study examines one venogram and another anatomic specimen in which the superior petrosal vein and sinus were absent.

Results:

The superior petrosal veins, described as 1–3 bridging veins, emptying into the superior petrosal sinus, are the major drainage pathways of the petrosal group of posterior fossa veins. In the cases presented, the superior petrosal vein and sinus were absent and venous drainage was through the galenic and tentorial groups, including the lateral mesencephalic or bridging vein on the tentorial cerebellar surface.

Conclusions:

In cases in which the superior petrosal sinus and veins are absent, care should be directed to preserving the collateral drainage through the galenic and tentorial tributaries. Although surgical strategies for intraoperative management and preservation of venous structures are still controversial, knowledge of the possible anatomical variations is considered to be essential to improve surgical outcomes.

Anatomic study of the lamina terminalis: neurosurgical relevance in approaching lesions within and around the third ventricle

BACKGROUND

The lamina terminalis (LT) represents an important neurosurgical corridor by which to fenestrate the third ventricle into the subarachnoid space or to approach lesions of the third ventricle. However, a comprehensive review of its anatomy and approaches to it for various pathologies is lacking in the literature. We studied the anatomy of the LT in 21 cadavers and described the LT as observed in cadaveric dissections. We also reviewed the literature regarding the detailed anatomy and pathology of the LT. In addition, a case illustration that demonstrates the use of this structure as a corridor to third ventricular tumors is presented. Our aim was to explore the anatomy of the LT through cadaveric dissection, a review of the literature, and a case study.

METHODS

Twenty-one adult cadaver heads underwent microdissection of the LT with a focus on the working distance available to enter the third ventricle and related vascular structures.

RESULTS

Inferior to the anterior communicating artery was the safer region to open due to the lack of perforating arteries. A working distance of approximately 1 cm can be expected through the LT.

CONCLUSIONS

This information may aid neurosurgeons during approaches through and around the LT.

Safety of ablation of the sigmoid and transverse sinuses: an experimental study

If the sigmoid and transverse sinuses could be divided safely, surgeons could broaden their access during skull base surgery without retracting the brain extensively. We undertook this study in monkeys to assess the risk of sacrificing these sinuses. We learned that when bilateral transverse sinuses were occluded, the sinus pressure measured in the superior sagittal sinus increased significantly as blood was purged from sinus venules. Unilateral sacrifice of sigmoid and transverse sinuses, however, did not change proximal sinus pressure in any ipsilateral or contralateral sinus. Furthermore, no change in regional cerebral blood flow or motor evoked potentials was seen in the parietal lobe nor did auditory brainstem response change significantly with sinus ablation. We conclude that, unilaterally, sigmoid and transverse sinuses may be ablated safely because collateral circulation via the vein of Labbé, superior petrosal sinus, petrosal vein, and backflow from the transverse sinus to the contralateral sinus may be established.

Surgical approaches to tumors of the anterior gyrus cinguli

BACKGROUND

Tumors of the gyrus cinguli are deep-seated, and may require a variety of surgical options. We focused on anterior tumors, which have specific anatomic and surgical features.

OBJECTIVE

To evaluate different approaches and indications through detailed description and a review of our experience.

METHODS

These approaches include unilateral interhemispheric or combined: bilateral interhemispheric, unilateral plus superior frontal gyrectomy, or unilateral plus frontal polectomy. The relevance of this retrospective analysis is stressed by the extremely limited literature in this regard.

RESULTS

In the past 5 years we operated on 38 patients with gliomas. We compared the following variables: location (perigenual, prerolandic), pathology (glioblastoma, other gliomas), size (<4 cm, > or =4 cm), extension (unilateral, bilateral), and approach (unilateral interhemispheric, combined). The only significant association we found was between tumor location (perigenual) and bilateral extension (P < .01). However, combined approaches were adopted only slightly more frequently in this region than in the prerolandic area, and this resulted in a lower rate of total removal (33% vs 76%, P < .01). Gross total removal was achieved in 28 cases (66%) and was significantly associated with combined approaches (77% vs 50%, P < .05).

CONCLUSIONS

The choice of a combined approach to anterior gyrus cinguli tumors is critical to improving the quality of resection in selected cases. We recommend a combined approach in the surgical treatment of large tumors of the perigenual area.

The petrosal approach for the total removal of giant retrochiasmatic craniopharyngiomas in children

OBJECT

The surgical removal of retrochiasmatic craniopharyngiomas, particularly those of giant size, remains a formidable challenge. The posterior petrosal (or presigmoid transtentorial) approach provides wide, direct exposure of these tumors, which allows safe neurovascular dissection and facilitates their total removal.

METHODS

Two patients, one 7-year-old girl and one 4-year-old girl, harboring giant retrochiasmatic craniopharyngiomas underwent total resection via the posterior petrosal approach. Both patients had good outcomes, and no evidence of recurrence was noted in either patient after 3 years of follow up. The surgical technique used in these patients is described. The trajectory of the petrosal approach is posterior-to-anterior and inferior upward. This is particularly valuable for dissecting the upper portion of the tumor, which projects high into the third ventricle. Using this approach, the surgeon can achieve direct visualization for dissection of the hypothalamus and pituitary stalk, while maintaining the blood supply to these structures and preserving their functional integrity. The small and poorly aerated mastoid sinus in children does not contraindicate the use or diminish the advantages of the petrosal approach.

CONCLUSIONS

The authors recommend this approach for patients with large or giant retrochiasmatic craniopharyngiomas.

Neurosurgery and the intracranial venous system

1) Numerous of the so-called "unpredictable" post-operative complications are likely to be related to the lack of prevention or non-recognition of venous problems, especially damages to the dangerous venous structures, namely: the major dural sinuses, the deep cerebral veins and some of the dominant superficial veins like the vein of Labbé. 2) Tumors invading the major dural sinuses (superior sagittal sinus, torcular, transverse sinus)--especially meningiomas--leave the surgeon confronted with a dilemma: leave the fragment invading the sinus and have a higher risk of recurrence, or attempt at total removal with or without venous reconstruction and expose the patient to a potentially greater operative danger. Such situations have been encountered in 106 patients over the last 25 years. For decision-making, meningiomas were classified into six types according to the degree of sinus invasion. Type 1: meningioma attached to outer surface of the sinus wall; Type II: one lateral recess invaded; Type III: one lateral wall invaded; Type IV: one lateral wall and the roof of the sinus both invaded; Types V and VI: sinus totally occluded, one wall being free of tumor in type V. In brief, our surgical policy was the following: Type I: excision of outer layer and coagulation of dural attachment; Type II: removal of intraluminal fragment through the recess, then repair of the dural defect by resuturing recess. Type III: resection of sinus wall and repair with patch (fascia temporalis). Type IV: resection of both invaded walls and reconstruction of the two resected walls with patch. Type V: this type can be recognized from type VI only by direct surgical exploration of the sinus lumen. Opposite wall to the tumor side is free of tumor, it is possible to reconstruct the two resected walls with patch. Type VI: removal of involved portion of sinus and restoration with venous bypass. 3) As 20% of the patients presenting with manifestations of intracranial hypertension due to occlusion of posterior third of the superior sagittal sinus, torcular, predominant lateral sinus or internal jugular vein(s) develop severe intracranial hypertension, venous revascularisation by sino-jugular bypass--implanted proximally to the occlusion and directed to the jugular venous system (external or internal jugular vein)--can be a solution.

Postoperative cortical venous infarction in tumours firmly adherent to the cortex

It is sometimes difficult to separate extra-axial tumours from the cortical veins in case of tumours attaching tightly to the cortex and the cortical veins. We present two patients having a postoperative cortical venous infarction. A 59 year old female had convexity meningioma above the motor cortex where abnormal cortical anastomotic veins developed. Transient hemiparesis occurred after total removal of the tumour because of venous infarction and cyst formation resulting from sacrifice of these veins which were tightly adherent to the tumour surface. A 15 year old boy with immature teratoma of the pineal region, showing several draining veins around the vascular-rich tumour, presented transient drowsiness, diplopia and partial impairment of bilateral visual acuity postoperatively because of localised cortical brain and venous damage. It is important to make an effort to preserve main cortical veins during operation as much as possible, even if the tumour adheres to the cortical surface.

Venous saving in olfactory meningioma's surgery

Bifrontal craniotomy and interhemispherical approach, usually used to remove olfactory groove meningioma, does not allow a view of posterior pole, which is very important in the surgical management of this neoplasm, and, provides for an anatomical sacrifice of frontal bridging veins, not without complications as a result of venous infarction. From 1975 the pterional approach was performed on 20 patients with olfactory meningioma, with good results in 90% of cases. This approach presents several advantages over bifrontal craniotomy and, in order to minimise surgical damage, it avoids planned sacrifice of venous vessels.

Correlation between venous stump pressure and brain damage after cortical vein occlusion: an experimental study

A canine model of cortical vein occlusion was used to evaluate whether data obtained from monitoring venous stump pressure could help predict cerebral infarction after venous obstruction. Following bilateral parasagittal craniotomy, the cortical vein in each hemisphere was temporarily occluded and the increase in pressure was directly measured. Permanent venous obstruction was subsequently produced, and parenchymal brain damage 24 hours later was classified as: Stage 0, no parenchymal damage; Stage I, mild edema; Stage II, moderate parenchymal edema and/or ischemic changes in neurons; and Stage III, moderate-to-severe hemorrhage. The histological stages correlated closely with the rise in venous pressure: mean pressure increases (+/- standard deviation) were 5.5 +/- 2.9 mm Hg in hemispheres graded as Stage 0 (12 hemispheres), 7.7 +/- 3.2 mm Hg in those graded as Stage I (five), 11.2 +/- 4.1 mm Hg in those classed as Stage II (five), and 16.4 +/- 5 in those categorized as Stage III (seven). There were significant differences between Stages 0 and II (p < 0.01) and between Stages 0 and III (p < 0.001). Disruption of the blood-brain barrier as indicated by extravasation of Evans blue dye correlated well with the pressure increment. These results may indicate the threshold for injury after cortical venous occlusion. Venous stump pressure measurements obtained during a test occlusion may be a useful adjunct in predicting brain damage and may be helpful for intraoperative vessel selection for venous resection.

Bifrontal basal interhemispheric approach to craniopharyngioma resection with or without division of the anterior communicating artery

The authors describe the use of a bifrontal basal interhemispheric approach with or without division of the anterior communicating artery (ACoA) for removal of large craniopharyngiomas. This approach is a more basal modification of the anterior interhemispheric approach; allowing preservation of most bridging veins. Since 1988, 22 patients underwent operations using this approach to achieve total or near-total excision of large craniopharyngiomas. Division of the ACoA was performed in 11 of 17 patients with retrochiasmatic tumors with no early or late complications related to division of the artery. There were no operative mortalities. Visual improvement (59%) and preservation of the pituitary stalk (64%) were achieved in a high percentage of patients. Preservation of the pituitary stalk correlated well with postoperative pituitary function. The bifrontal basal interhemispheric approach allowed a bilateral, wider operative field with better orientation and views of important neural structures and perforating arteries without requiring combination with other approaches. When the ACoA limited operative exposure, the artery could be divided safely. The authors discuss indications for, and advantages of, the bifrontal basal interhemispheric approach with or without division of the ACoA in the removal of large craniopharyngiomas.

Changes in the cerebrocortical capillary network following venous sinus occlusion in cats

BACKGROUND

Although the important protective effect of venous collateral pathways in sinus occlusion on parenchymal injury has been demonstrated in previous works, the vascular response in the capillary microcirculation itself after cerebral venous occlusion has not been fully elucidated. We examined the morphology of the capillary network after venous occlusion by relating stereologic morphometric parameters to changes in local cerebral blood flow and the development of brain edema.

METHODS

Experimental venous sinus occlusion was induced by injection of 0.5 mL of cyanoacrylate into the superior sagittal sinus and by immediate ligation of both external jugular veins in chloralose-urethane anesthetized cats (n = 24). Capillaries in the adjacent cortex (marginal and suprasylvian cortex) and remote cortex (piriform cortex) were injected with Evans blue dye 2 minutes before sacrifice at 15-minute and 120-minute postsinus occlusion. The stereologic morphometric parameters including volume density, minimum intercapillary distance, capillary diameter, and number of perfused capillaries were computed on a fluorescence microscopic photograph using an image analysis system. Cerebral blood flow (CBF) was measured by hydrogen clearance method, and brain tissue water content was measured using the dry-wet method.

RESULTS

In the cortex adjacent to the superior sagittal sinus, the volume density and the number of perfused capillaries were increased significantly (p < 0.02, and p < 0.05, respectively) and the minimum intercapillary distance was decreased significantly (p < 0.02) at 15 minutes after venous occlusion (n = 10). Cerebral blood flow (CBF) was also decreased to 53% of that in the control group (p < 0.01). Although the morphologic parameters returned to the control level by 120 minutes after venous occlusion, the CBF remained decreased after venous occlusion. No change was observed in the water content of the adjacent gray matter at 15 minutes after venous occlusion; however, it was increased (p < 0.05) at 120 minutes.

CONCLUSION

These results indicate that the recruitment of reserve capillaries occurs during the early phase of venous occlusion. While CBF decreased to half of the control after venous occlusion, capillary perfusion remained above or near the control level until 120 minutes postocclusion, suggesting that venous recruitment would be potentially beneficial in clinical patients in the early stage of venous occlusion.

Basal interfalcine approach through a frontal sinusotomy with vein and nerve preservation. Technical note

The authors describe a new method for a frontal interhemispheric approach when treating craniopharyngiomas of the third ventricle or anterior communicating artery aneurysms. This technique ensures preservation of the bridging veins and the olfactory nerves. This "basal interfalcine approach" involves a craniotomy in the centrobasal portion of the frontal bone (the frontal sinus), removal of the inner tables and the crista galli, and splitting the basal portion of the falx into two leaves, through which the basal interhemispheric fissure is opened. The olfactory nerves are protected by the leaves of the falx, and the bridging veins are preserved because the approach is low enough to spare them. The surgical techniques are described together with a unilateral variation of this approach. The significance of preserving the bridging veins is discussed in connection with avoidance of postoperative contusional hemorrhage.

A pitfall in the interhemispheric translamina terminalis approach for the removal of a craniopharyngioma. Significance of preserving draining veins. Part II. Experimental study

The authors have reported a case of a craniopharyngioma removed by the interhemispheric translamina terminalis approach, and the postoperative development of a subcortical hematoma. We suspected that the cause of the subcortical hematoma was dividing the bridging veins and applying a retractor over them. In this paper, we report our experimental study, using dogs and monkeys, to evaluate the effect of cutting the vein and applying a retractor over it. The incidence of a subcortical hematoma was highest (60%) when the veins were cut and the retraction was applied. Vein occlusion only did not cause hematoma to develop, and the retraction alone caused 13% of the hematomas. This clearly indicated that the clinical case reported in Part I developed the subcortical hematoma postoperatively because the frontal bridging vein was cut and a retractor was applied for 60 minutes over the cut vein.