Alexia without agraphia in a musician after transcallosal removal of a left intraventricular meningioma.

After a meningioma situated in the trigone of the left lateral ventricle was excised by the transcallosal approach of Kempe and Blaylock, a right-handed musician with a right hemianopsia developed alexia without agraphia. In contrast to previously reported cases of this syndrome arising from other etiologies, he was unable to read single letters or numbers. Neuropsychological studies at 42 and 126 days after operation also disclosed an inability to associate auditory or tactile stimuli with visually perceived material, whereas speech and verbal comprehension were intact. Although the alexia extended to musical notes, he could interpret other musical symbols (e.g., treble clef). Appreciation of rhythm and expressive musical ability were relatively preserved, although judgment of other musical features (including discrimination of pitch, duration, and loudness) was compromised. The findings suggest that alexia may occur as a consequence of the transcallosal procedure when a right hemianopsia is present. However, other linguistic abilities may be better preserved by the transcallosal approach to the ventricle than by a transcortical operation.     

Surgical approaches to tumours of the lateral ventricles in the dominant hemisphere

BACKGROUND: Intraventricular neoplasms are rare tumours (1% of the tumours of the central nervous system). The surgical approach sometimes is quite difficult, particularly in the dominant hemisphere. The best choice of surgical approach is discussed. METHODS: The authors describe a series of 25 patients who underwent surgical treatment for tumours situated in the lateral ventricles of the dominant hemisphere. They discuss the most influential factors in the choice of surgical approach, which must allow maximum exposure of the lesion and vascular feeding branches without damaging highly functional areas (motor, visual and language areas). In particular, they report their experience using a low transtemporal route, between the middle and inferior gyri, for removing tumours localized in the temporal horn and/or trigone which made it possible to keep postoperative visual and phasic deficits to a minimum. RESULTS: In 5 patients the approach was transfrontal, in 10 temporal, in 6 superior parieto-occipital and in 4 transcallosal. Three patients died. Only 5 patients presented permanent deficits (anomia, apraxia and visual fields alterations). CONCLUSIONS: The size, site, hemisphere and vascularization of intraventricular tumours influence the choice of surgical approach. The basal transtemporal approach is particularly indicated to remove tumours of the temporal horn and trigone and it seems to reduce the risk of speech disturbances and alterations of posture.     

Arteriovenous malformations of the lateral ventricle

Nine cases with arteriovenous malformations (AVM's) predominantly involving the lateral ventricle are presented. All the AVM's were small, but caused intraventricular hemorrhage in eight cases. Only two patients had an intracerebral hemorrhage large enough to warrant evacuation. Eight patients were under the age of 40 years at the onset of their disease. Computerized tomography demonstrated intraventricular hemorrhage in eight patients, and after intravenous administration of contrast medium a small area of enhancement with dilated subependymal draining veins was seen in seven. The lateral ventricles were of normal size in seven cases, and only two patients required a shunting procedure. Angiography demonstrated that the lesion was an AVM in eight patients, and did not visualize the lesion in the ninth. One patient suffered a recurrent intraventricular hemorrhage when the AVM was demonstrated, although repeated angiography had failed to disclose a vascular lesion at his first intraventricular hemorrhage 14 months before. All nine lesions were resected by microsurgical techniques, and the results were excellent in eight patients. Of four caudate lesions, three were resected through a frontal transcortical approach and the other was operated on through an anterior transcallosal approach; the results were excellent in three of these patients. Only one (Case 4) was left with neurological deficits; he had confusion and disorientation following a right frontal transcortical approach. Even in the dominant hemisphere, lesions in the head of the caudate nucleus could be safely resected by an anterior transcallosal approach. Two choroidal lesions located in the temporal horn and trigone on the dominant side were resected through a middle temporal gyrus approach, and three thalamic lesions through a posterior transcallosal approach, all with excellent results. In all cases the brain opening required was about the width of the retractor (maximum 2.0 cm, average 1.5 cm).     

Transcallosal, transventricular approach to a basilar apex aneurysm.

A new approach to the basilar apex in a patient with a megadolichobasilar anomaly and an abnormally rostral basilar apex aneurysm is described. The details of the surgical approach and the advantages and limitations of this transcallosal, interseptal approach are described.     

Endoscopic approaches for third ventricular tumors

Endoscopic approaches for third ventricular tumors, both transcortical and transcallosal approaches, are described. A 4-mm diameter, 0-degree rod-lens endoscope is used in both procedures, and angled rod-lens endoscopes are used for angled views. The transcortical transventricular approach is made via a burr hole placed at the nondominant frontal area, 1-inch lateral to the midline along the coronal suture. A folded vinyl tube, which can be expandable to a 1-cm tube by unfolding, is placed into the lateral ventricle toward the tumor under an image-guidance system. The transcallosal approach is made via a burr hole placed along the lateral margin of the superior sagittal sinus at the nondominant frontal area. The surgical corridor is made along the interhemispheric fissure. A rolled, cigarette-shaped, cotton patty is placed anteriorly and posteriorly along the surgical trajectory to keep the corridor open. The corpus callosum is opened, and the tumor is removed with surgical instruments inserted through the supported corridor parallel with the endoscope, which is mounted to an endoscope holder. Endoscopic transcortical and transcallosal approaches for the removal of third ventricular tumors are described. Compared with endoscopy performed through fixed working-channels, these techniques increase flexibility for surgeons to maneuver surgical instruments for delicate microdissection and tumor removal.     

Anterior lateral ventricular subependymal giant cell astrocytomas

Summary The surgical managagement of two cases of lateral ventricular subependymal giant cell astrocytoma, arising in the head of the Caudate nucleus, and causing hydrocephalus due to obstruction of the foramen of Monro is described. One lesion, in a patient with tuberous sclerosis, was resected using a transcallosal approach and the other, in a patient with no stigmata of tuberous sclerosis, using a frontal, trans-cortical transcystoventricular approach. The microsurgical aspects of excision and pathological anatomy of both tumours were very similar. Following tumour excision and pellucidotomy both patients had partial resolution of their hydrocephalus with complete resolution of their preoperative symptoms. The merits of transcallosal and transcortical approaches to these lesions are discussed.     

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.     

The Transcallosal Anterior Interfoniceal Approach: A Microsurgical Anatomy Study

Objectives A plethora of surgical strategies have been described to reach deep-seated lesions situated within the third ventricle including the Rosenfeld, or transcallosal anterior interfoniceal (TAIF), approach. First introduced in 2001, it consists of a small callosotomy followed by the midline transseptal dissection of fornices to enter the roof of the third ventricle. The aim of this microsurgical anatomy study is to describe and show each stage of the surgical procedure, focusing on the possible trajectories to anatomical landmarks. Participants A total of 20 adult cadaveric specimens were used in this study. Using ×3 to ×40 magnifications, the surgical dissection was performed in a stepwise fashion, and the transcallosal anterior interforniceal approach was performed, analyzed, and described. Results In 5 specimens of 10, a cavum septum pellucidum was depicted. In 5 cases of 20 after the callosotomy ,the lateral ventricular cavities were reached. Different orientation of the microscope allowed us to define three surgical trajectories to visualize the region of interest without exposing important functional areas. Conclusion The TAIF represents a minimally invasive approach to the third ventricle; its tricky surgical steps make appropriate anatomical dissection training essential to become confident and skilled in performing this approach.     

Occipital inter-hemispheric approach for lateral ventricular trigone meningioma

Objective  

The optimal surgical approach for a trigone meningioma is still controversial. Here, we report two patients with trigone meningioma treated successfully via an occipital inter-hemispheric and trans-cortical approach in the lateral semi-prone position.     

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.     

Pre-coronal, paramedian minicraniotomy: a minimal access approach for microsurgical, transcallosal, transforaminal removal of colloid cysts of the third ventricle

OBJECTIVE: Microsurgical excision of colloid cysts of the third ventricle is accomplished along the transcallosal or the transfrontal routes. In the transcallosal approach, venous tributaries of the superior sagittal sinus can often act as an impediment to entry into the interhemispheric fissure for accessing the corpus callosum. We propose a paramedian minicraniotomy anterior to the coronal suture for removing colloid cysts via the transcallosal approach as veins are relatively rare in this area. METHODS: A triangular minicraniotomy was designed with each side measuring 3 cm based on the midline in the pre-coronal area of the frontal bone on the right side. Nineteen cases of symptomatic colloid cysts of the third ventricle whose diagnoses were proven by CT and/or MRI were subjected to microsurgery in the period from June 2004 to May 2007. Following the minicraniotomy the cysts were removed utilizing the transcallosal transforaminal route. RESULTS: Venous tributaries crossing the interhemispheric fissure were seen in 2 patients and these could be avoided to access the corpus callosum. Complete excision could be achieved in all cases. All patients had a good outcome although one patient had transient left lower limb weakness. The mean operating time was 163 minutes, while the mean duration of stay in the intensive care unit and hospitalization were 1.35 days and 3.73 days, respectively. CONCLUSION: The pre-coronal, paramedian minicraniotomy is safe and effective for the total excision of colloid cysts of the third ventricle. As a minimal access approach, it needs only a short duration of postoperative hospitalized care.     

Anterior trans-frontal endoscopic management of colloid cyst: an effective,safe, and elegant way of treatment. Case series and technical note from a multicenter prospective study

Different management options are available for the treatment of colloid cysts. Goals of those procedures are to achieve a complete resection avoiding potential long-term recurrence along with CSF pathways restoration with minimal morbidity and mortality. The two main surgical options are endoscopic resection or direct removal by either transfrontal or transcallosal approach. The efficacy of endoscopic technique to achieve gross total colloid cyst excision has been well documented. In the present study, authors describe a series of 29 patients who underwent surgery by a variation of the standard worldwide implemented endoscopic technique. Using a more anterior approach, it is easier to reach the roof of the cyst, its possible adherences with the tela choroidea, plexus, and the internal cerebral veins. The described approach has shown to be safe, quick, and very effective with a total cyst removal rate of 86.2 %.     

Long-term effects of partial callosal lesions

Summary Ten patients with partial callosal lesions were investigated with a broad scale neuropsychological assessment. Nine patients with a variety of lesions affecting midline structures have been operated using a direct transcallosal approach, one patient with a callosal lipoma remained unoperated. Sophisticated studies of the interhemispheric transfer of somaesthetic and perceptual motor tasks, as well as psychometric testing related to parameters of memory and attention performance were applied. The results indicate that there is no clear correlation between the site of callosal lesion and clinical symptoms. Although special disconnecting symptoms due to callosal dissection could be found, they didn't reach clinical significance. The most severe symptoms of impairment were caused by the extracallosal pathology. The results indicate that the transcallosal approach is a safe and feasible alternative in the management of pathological lesions in the midline region.     

Giant meningioma of the third ventricle

Summary The authors report a rare case of a giant meningioma in the third ventricle operated on by the transcallosal approach following bifrontal craniotomy. The CT findings and the operative procedures are discussed.     

Surgical anatomy and surgical approaches of the third ventricle

Careful analysis of MRI images is mandatory before any surgical procedure in the third ventricle. This analysis should take in account the relationship of the tumor itself, but also the grade of hydrocephalus and the main anatomical landmarks along the surgical approach. The first step is the access to the lateral ventricle, which may be achieved via transcortical or anterior transcallosal routes : these two operative procedures are detailed. The transforaminal entry to the third ventricle may be easy if hydrocephalus has widened the foramen of Monro. In other cases, a subchoroidal (or interthalamo-trigonal) approach is necessary, and the division of the thalamostriate vein is sometimes required. In this series, the transcortical route has been favoured by neurosurgeons. The advantages and drawbacks of both transcortical and anterior transcallosal routes are discussed. The anterior interhemispheric and pterional approaches are briefly evoked, as they were used in very few cases of this series. The management of hydrocephalus is discussed.     

Ureteral severance during retropubic prostatectomy Rare complication of bladder herniation

A case is described of a seventy-three-year-old man undergoing retropubic prostatectomy when the right ureter was severed. This rare complication was apparently due to the anterior rotation of the trigone, caused by a huge contralateral inguinal scrotal hernia which included the bladder.     

Intraventricular hemorrhage in a term neonate secondary to a third ventricular AVM. Case report

An initially healthy infant born of an uncomplicated full-term gestation was brought for evaluation of the acute onset of vomiting, irritability, lethargy, and opisthotonus at 14 days of age. Computerized tomography demonstrated an intraventricular hemorrhage. Arteriography defined an angioma on the roof of the third ventricle which was successfully removed via the transcallosal interfornicial approach on the 34th day of life. Other than an easily controlled seizure disorder, the postoperative course was uneventful. At 8 months of age the child is developing normally. Arteriovenous malformations should be considered in the differential diagnosis of intraventricular hemorrhage in full-term neonates without predisposing trauma or bleeding diathesis. High-speed digital subtraction arteriography may be used to screen for this diagnosis. The transcallosal interfornicial exposure offers a satisfactory approach for excising third ventricular angiomas in young infants.     

Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle

OBJECT: Endoscopic surgery has been reported to be more cost-effective and safer than open craniotomy for resection of colloid cysts, despite a 5-10% conversion rate to craniotomy, a 5% recurrence rate, a 5-10% ventricular shunting rate, a 5-10% epilepsy rate, and a 3-4 day hospital stay. In 1985, the authors developed a interhemispheric, transcallosal, subchoroidal, fornix-sparing approach that allowed safe total resection of the colloid cyst and that appeared to be superior to the endoscopic approach. The long-term results are analyzed and compared with findings in the literature. METHODS: Fifty-seven consecutive colloid cysts were totally removed via a 3 x3-in paramedian craniotomy flap and a microscopic interhemispheric, transcallosal, subchoroidal approach sparing the ipsilateral fornix. The length of the callosotomy was 1.5-2 cm in all patients. The mean follow-up duration was 12 years (range 2-22 years). A retrospective analysis comparing the authors' results with those reported in the endoscopic literature was performed. RESULTS: All patients had 1-year postoperative imaging studies (CT or MR imaging) documenting gross-total resection with no deaths, infection, hemiparesis, seizures, or disconnection syndrome. One surgery was complicated by bilateral subdural hematomas, which were successfully treated. There has been a zero recurrence rate. Three patients required a permanent ventriculoperitoneal shunt (including 2 who required emergency ventriculostomy before surgery). The mean hospital stay was 4.8 days (range 2-24 days). There was 1 patient with permanent short-term memory loss who presented with a herniation syndrome requiring emergency ventriculostomy. CONCLUSIONS: The interhemispheric, transcallosal, subchoroidal, fornix-sparing approach to gross-total resection of colloid cysts is safe and led to a zero recurrence rate with no permanent neurological sequelae including epilepsy, and these results are superior to any reported results with endoscopy.     

Trigone sensitivity testing is a measure of exteroceptive function

The trigone sensitivity test, a complementary test to cystometry, has been proposed as a method for distinguishing certain clinical disorders. Pressure is applied to the trigone region of the bladder by pulling upon a Foley catheter with the balloon inflated and the amount of force needed to induce an urge to void is recorded. Although the trigone sensitivity test has been proposed as a test of exteroceptive function, it is possible that deeper receptors, perhaps proprioceptors, are actually responsible for the awareness of the urge to void during the study. The present investigation compared the trigone sensitivity test with provoked detrusor contraction in 107 patients. The findings indicate that variations in the two responses occur independently of each other. It is concluded that different neural pathways are responsible for the two functions. The hypothesis that exteroceptive and not proprioceptive nerves are being measured during trigone sensitivity testing is supported by these findings.