Stereotactic diagnosis and treatment of pineal region tumours and vascular malformations

Summary Diagnosis and treatment of tumours and vascular malformations in the region of the pineal gland continue to challenge the neurosurgeon's skill. Due to vital vascular and brain structures in the region, microsurgical removal of such masses is often impossible.During the past nine years, we have managed 47 patients with pineal region mass lesions using stereotactic techniques for diagnosis and treatment. In order to determine further therapeutic options, 15 patients underwent stereotactic biopsy of pineal region tumours. In all patients, the histologic diagnosis obtained served to direct further therapy. Thirty-two patients were treated with stereotactic radiosurgery for pineal region tumours or vascular malformations. During the follow-up period, one patient underwent delayed microsurgical resection of a midbrain angiographically occult vascular malformation. No other patient required microsurgical intervention after a stereotactic procedure. In all 47 patients, no significant morbidity or mortality occurred after stereotactic biopsy or radiosurgery. Empiric treatment of pineal region tumours with fractionated radiation therapy is no longer warranted. Image-guided stereotactic technology provides a safe method to accurately diagnose and effectively treat selected pineal region masses. After definitive histologic diagnosis is established, proper treatment may be instituted. Options for treatment include stereotactic radiosurgery for selected tumours and vascular malformations, microsurgical resection of benign tumours or fractionated external beam radiation therapy for malignant germ cell and glial tumours. Stereotactic surgery should be the first option in the diagnosis and therapy of pineal region masses.Presented at the American Association of Neurological Surgeons Annual Meeting, New Orleans, LA, April 24th, 1991.     

Endoscopic treatment of intracranial lesions. Apropos of 8 cases

The authors describe their initial experience involving endoscopic techniques used in the treatment of eight patients with varied brain lesions. Two tumours and a colloid cyst of the third ventricle, two paraventricular symptomatic cysts, one arachnoid cyst, one chronic intracerebral hematoma and one case of free catheter extraction in the lateral ventricle. The common characteristics of all these lesions were their liquid character and/or intraventricular location. Rigid endoscopes were used, with 9 and 6 mm work channels and independent aspiration and irrigation systems. The optic elbow makes direct visualization and adaptation to the TV monitor possible. The endoscope was manually directed at the lesion through a 12 mm burr hole in five cases and by means of a stereotactic frame in three cases. Biopsies were obtained in six cases. In three cases a communication between the cyst and the ventricular system or adjacent cisterns was established and in two cases vaporization of the lesion using a CO2 laser was performed. Tolerance to the endoscopic procedures was good in all cases. In the authors' opinion, endoscopic techniques constitute a low risk method, midway between stereotactic techniques and the microsurgical approach, and are especially indicated in the treatment of cystic brain lesions or those situated in or near the ventricular system. Their most notable advantages are: providing direct visualization of the lesion without interference from the instruments in the operating field; non-repercussion of the spatial changes derived from the liquid outlet and possibility of lesion coagulation and manipulation. Their disadvantages, related to the use of very long instruments and from a reduced work channel, must be overcome by specialized training.     

Stereotactic craniotomy and intraoperative lesion localisation using the Brown-Robert-Wells frame

Summary A simple technique of stereotactic craniotomy and intraoperative lesion localisation that uses the Brown-Robert-Wells (BRW) stereotactic frame is presented. The method optimises craniotomy placement and facilitates localisation of small intracerebral lesions. Using the system, 16 patients have had resection of intracranial neoplasms from deep and/or eloquent areas of the brain with no neurological morbidity.     

New microsurgical technique for intraparenchymal lesions of the brain: transcylinder approach

Summary Background. Although various minimally invasive approaches, including endoscopic, stereotaxic, and ultrasound-guided surgery, have been introduced to minimize damage to healthy brain tissue, the microsurgical technique has retained a significant role in contemporary neurosurgery. A new microsurgical approach to intraparenchymal brain lesions, namely, the transcylinder approach, was developed to realize both minimal surgical access and sufficient microsurgical technique. Method. A 0.1-mm transparent polyester film was used to create a cylindrical surgical route. The film was rolled into a thin stick and used to penetrate the brain, and a computer-aided navigation system was used from inside the stick to access the lesion accurately. After the stick gained access to the lesion, it was dilated to 2 cm, and this diameter was maintained during surgery. Findings. The transcylinder approach was used in 11 cases, including intraparenchymal tumours and haematomas, and the usual microsurgical procedure was performed without difficulty. The film avoided unnecessary enlargement of the surgical field and minimized injury to the brain. Intra-operative ultrasonography also can be used to identify the lesion through the cylinder because the polyester film does not reflect the ultrasound beam. The surgical route was observed to recover to almost the same size as the initial cortical incision after removal of the cylinder. Conclusions. The transcylinder approach could be advantageous for removing tumours or haematomas in the intraventricular or intraparenchymal regions. By avoiding unnecessary retraction, it significantly reduces the risk of injury to surrounding brain tissue while facilitating precise microsurgical technique. The accuracy of this minimally invasive technique can be enhanced when used in conjunction with frameless stereotaxy and intra-operative ultrasound guidance.     

Image-guided endonasal transsphenoidal microsurgical treatment of recurrent microadenomas of the pituitary gland.

BACKGROUND: Neuronavigation is a commonly used technology that provides continuous, three-dimensional information for the precise localization of and surgical trajectory to brain lesions. This study was performed to evaluate the role that navigation can play in assisting microsurgical transsphenoidal surgery for precise localization and removal of recurrent pituitary tumours while simultaneously preserving pituitary gland function. METHOD: During a 6-month period -- July 2004 until December 2004 -- 9 patients with recurrent pituitary tumours (5 female and 4-male) were treated with navigation-guided transsphenoidal microsurgical resection. Surgery was performed via a paraseptal or endonasal transsphenoidal approach. The navigation system Vector Vision (Brain Lab, Heimstetten, Germany) allowed precise localization of the tumours (7 hormonal active and 2 inactive microadenomas) in respect to the pituitary gland, the carotid arteries and the cavernous sinus. RESULTS: Postoperative MRI investigations of the 9 patients treated with image-guided transsphenoidal microsurgery, showed total tumour removal in 7 (77 %) patients and subtotal removal in 2 patients (23 %). One patient (11 %) developed a cerebral spinal fluid (CSF) leak and was treated conservatively. One patient (11 %) had preoperative insufficiency of the corticotrope axis which remained unchanged postoperatively. Of the remaining 8 patients who did not have preoperative endocrinological disturbance, only one (12 %) developed postoperative insufficiency of the corticotrope axis. Out of the 7 patients with hormone active tumours, 5 (72 %) patients showed no more postoperative hormonal activity. CONCLUSION: Microneurosurgical transsphenoidal techniques combined with image-guided systems can precisely define the localization and removal of lesions in the sella region with respect to the margins of important anatomical structures in the neighbourhood and the endocrinological functionality of the pituitary gland.     

Transsulcal microsurgical approach for subcortical small brain lesions: technical note

We describe a transsulcal microsurgical approach for removal of small subcortical brain lesions, guided by frameless stereotaxy. This technique of simultaneous stereotactic localization of the subcortical lesion and its adjacent sulcus, before surgical approach, results in optimal surgical planning, leading to minimal brain tissue loss and excellent surgical outcome.     

Intraoperative low-field MR-guided frameless stereotactic biopsy for intracerebral lesions

Background

To present our intraoperative low-field magnetic resonance imaging (ioMRI) technique for stereotactic brain biopsy in various intracerebral lesions.

Method

Seventy-eight consecutive patients underwent stereotactic biopsies with the PoleStar N-20/N-30 ioMRI system and data were evaluated retrospectively. Biopsy technique included ioMRI before surgery, followed by insertion of the biopsy cannula in the lesion, and ioMRI before and after biopsy. Statistical analysis was performed to compare subgroups using Excel and SPSS statistic software.

Results

In all patients, stereotactic biopsy was possible, with a mean intraoperative surgery time of 86.2?±?28.6 min and a mean hospital stay of 11.6?±?4.6 days. In 97.4 % (n?=?76), histology was conclusive, representing 58 brain tumors and 18 other pathologies. Five patients were biopsied previously without conclusive diagnosis, and all biopsies were conclusive this time. Mean cross-sectional lesion size in MRI T1 with contrast (n?=?64) was 6.9?±?5.7 cm², and in lesions without T1 contrast enhancement (n?=?14), T2 mean cross-sectional lesion size was 5.5?±?3.9 cm². Mean distance from the cortex surface to the lesion was 3.4?±?1.2 cm. One patient suffered from a postoperative wound dehiscence; neither clinically or radiologically significant hemorrhage after surgery, nor intraoperative complications occurred.

Conclusions

Low-field ioMR-guided frameless stereotactic biopsy accurately diagnosed different intracerebral lesions without major complications for the patients, and within an acceptable surgery time and hospital stay. In repeated non-conclusive biopsies in particular, low-field ioMRI offers a technique for arriving at a diagnosis.     

The stereotactic volumetric information: its role in two-step resection of brainstem and thalamic giant tumor. Report of three cases and technical note

BACKGROUND: A compact intracerebral tumoral lesion is usually considered to be completely resectable. Nevertheless, radical resection of a huge lesion located in a critical area may damage the surrounding compressed brain tissue. In cases with a good prognosis, a two-step removal appears to be a safer strategy. METHODS: In three cases, two with huge brain stem lesions and one with a thalamic lesion, a two-step volumetric stereotactic resection was planned. This strategy allowed us to evaluate the amount of tumor to be removed during the first procedure and to have, during the second operation, an exact definition of the reduced mass with regard to the scar tissue and postoperative adhesions. Furthermore, we avoided significant shifting of the cerebral structures during both procedures. RESULTS: There was a very good final recovery in the cases with brain stem lesions and a minimal deficit in the patient with the thalamic lesion. The patient with a mesencephalic lesion remained comatose for almost 2 days after the first procedure, confirming our fears about too radical a one-step resection. CONCLUSIONS: We think that by using current techniques, it is possible to remove a well circumscribed lesion regardless of its position. This is probably easier with giant lesions where a safe trajectory can be planned. In these cases, with lesions located in very critical areas but with a good prognosis, a two-step resection appears to be a good option.     

Treatment of deep brain abscesses by stereotactic implantation of an intracavitary device for evacuation and local application of antibiotics

Summary Complete recovery from deep brain abscesses was achieved in four patients treated by a specialized stereotactic method. In one patient the lesion was in the right thalamus, in two patients within the brain stem and in one case in the right rolandic cortex. The technique consists in the stereotactic implantation of a chronic intracavitary catheter connected to a subcutaneous reservoir to allow postoperative multiple evacuations and local antibiotic irrigations. Serial CT scan examinations guided the timing of intracavitary treatment and the removal of the catheter. No recurrence developed. The diagnostic and therapeutic advantages of this stereotactic technique are emphasized.     

Minimally invasive craniotomy using the Steiner-Lindquist stereotaxic guide.

Thirty-three obscure intracranial lesions were located using the Steiner-Lindquist microsurgical stereotaxic guide and then surgically resected. Seventeen of the lesions were located in the parietal region, six in the frontal region, three in the parietooccipital region, three in the temporoparietal region, one in the thalamic region, one in the centrum semiovale, one in the brainstem, and one in the third ventricle. Twenty-three lesions were in subcortical or cortical locations. In 28 cases, the lesion was totally removed, while in 5 the lesion was subtotally resected. Pathological examinations confirmed glial tumor in eight patients, metastasis in seven, meningioma in two, cavernous angioma in eight, arteriovenous malformation (AVM) in four, hematoma in two, dysembryoblastic neuroepithelial tumor in one, and septum pellucidum cyst in one. Two patients developed transient complications postsurgery. Mean lesion size was 23 +/- 0.97 mm. The hospitalization period ranged from 1 to 6 days (mean 3.4 +/- 1.3 days). Surgeries were performed under general anesthesia, or under local anesthesia with the patient awake. The Steiner-Lindquist microsurgical stereotaxic guide is useful for pinpointing small lesions, especially those in the subcortical and deep areas. Knowing the precise location of the lesion facilitates removal through a small craniotomy incision. This minimally invasive procedure reduces the number of postoperative neurological complications, and also cuts costs by shortening the hospital stay.     

Laser microsurgery for superficial lesions of the penis

A carbon dioxide laser microsurgical technique for partial or complete resection of superficial lesions of the penis is described. This technique was used in 47 patients from January 1982 to May 1985. Of the 47 patients 32 (68 per cent) were treated on an outpatient basis. Histological study of the lesions showed microscopically invasive cancer in 8 patients, carcinoma in situ in 4, grades II and III dysplasia in 5, hyperkeratosis or parakeratosis in 10, pigmented lesions in 2, papilloma in 1 and no residual disease after systemic chemotherapy for exophytic carcinoma in 3. Laser surgery was performed in 1 stage under constant microscopic visual control. The depth of the resection ranged from 0.5 to 2.6 mm. (mean depth 1.5 mm.). Surgical specimens were fit for a correct pathological examination when they were thicker than 0.5 mm. (95.7 per cent of the cases). Microscopically, the margins of the resection resulted in healthy tissue in 41 of the 45 evaluable specimens (87.2 per cent). The mean distance between the lesion and incision borders was 0.6 mm. (range 0.4 to 1 mm.). Of the 4 patients with microscopic evidence of disease at the resected margins 3 underwent another laser microsurgical procedure and 1 received external beam radiation. Healing by secondary intention had an average duration of 6 weeks. Cosmetic results were satisfactory in every patient. Only 1 patient (2 per cent) suffered complications (arterial hemorrhage). In conclusion, the short-term results of this surgical technique for penile lesions are satisfactory. Further followup is needed to evaluate the curative potential of this method.     

Multiple target aspiration technique for subacute stereotactic aspiration of hematomas within the basal ganglia

BACKGROUND: Stereotactic surgery for deep-seated intracerebral hematomas as a minimally invasive procedure has gained wide acceptance, but debate continues to be controversial concerning the issue of how to aspirate a sufficient proportion of the hematoma with minimized risk for the patient. The objective of this paper is to present a modified stereotactic aspiration technique which complies saliently with both demands. METHODS: The multiple target aspiration technique was used in a series of 64 consecutive patients with spontaneous hematomas within the basal ganglia. The results obtained with this technique were evaluated with particular regard to degree of aspiration and rate of recurrent hemorrhage and were compared with results achieved with stereotactic techniques utilizing physical fragmentation or chemical lysis of the clots. RESULTS: Using this technique, it was feasible in one single surgical procedure to aspirate more than 80% of the hematoma volume in 73.4% of the patients. Mean degree of aspiration was 88.8%, and rebleeding occurred only once (1.6%). These results compare favorably with those achieved with application of intricate stereotactic techniques. CONCLUSION: The multiple target aspiration technique performed in the subacute stage is a rapid and simple method for stereotactic removal of deep-seated hematomas and combines a high success rate with very low risk of recurrent hemorrhage.     

Stereotactic resection of occult vascular malformations

Angiographically occult vascular malformations can be identified on computerized tomography and magnetic resonance imaging. Surgical excision, when possible, is the treatment of choice in symptomatic lesions. Because these malformations are usually small and can be located in surgically treacherous areas of the brain, stereotactic resection should be considered. Stereotactic resection of a pathologically verified occult vascular malformation was performed in 26 patients in this series (13 females and 13 males, mean age 30 years). Seventeen patients presented with a seizure disorder, four with an intracerebral hemorrhage, and four with a progressive neurological deficit; one patient was asymptomatic. Sixteen patients had normal neurological examinations, nine had neurological signs referable to their lesion, and one had a visual field deficit related to a previous temporal lobectomy. In six patients evidence of acute hemorrhage was found on imaging studies or at surgery, and 11 patients had evidence of previous hemorrhage on imaging studies, determined at surgery or by histological examination. Three patients had evidence of both acute and previous hemorrhage and six patients had no evidence of hemorrhage. Lesions were located in cortical or subcortical areas in 21 patients, in the thalamus or basal ganglia in three, and in the posterior fossa in two. Following stereotactic resection, 24 patients were improved, one patient was unchanged, and one patient was worse. Without stereotaxis or intraoperative ultrasound studies, localization of these lesions at conventional craniotomy can be difficult. A stereotactic craniotomy is ideally suited to the treatment of these benign circumscribed, but potentially devastating lesions.     

Aggressive course of multiple de novo cavernous malformations

The risk of hemorrhage from an intracerebral cavernous malformation has been estimated at 2%-4% per year. In patients with multiple cavernous malformations, typically there are 1 or 2 dominant lesions that result in symptoms. This report highlights an unusual case of recurrent hemorrhage from de novo cavernous malformations. This 35-year-old man had a generalized seizure in 2007. Magnetic resonance imaging performed at the time showed multiple hemorrhagic lesions suggestive of cavernous malformations. Two years later, the patient had clinical symptoms referable to a midbrain hemorrhage. This lesion was not present on 2007 standard and gradient echo images. One year later, the patient had another clinical hemorrhage at the cervical medullary junction. This lesion was also not present on earlier imaging. Genetic testing was negative for the known familial types of cavernous malformation. A lesion was biopsied to ensure correct diagnosis, and the results were pathologically consistent with a cavernous malformation. The patient had a fourth clinical hemorrhage in 2011 from a separate lesion. All hemorrhage symptoms were mild, and he returned to normal functioning and work after each hemorrhage. This case highlights several unusual features of the known natural history of intracerebral cavernous malformations. In this case, resection of the hemorrhagic lesion would not have altered future hemorrhage risk since each new hemorrhage was from a de novo lesion.     

Colloid cysts — a review including 19 own cases

Between 1974 and 1987 19 patients harbouring colloid cysts of the third ventricle have been treated in our department. There were 12 male and 7 female patients with an average age of 34 years (ranging from 17 to 58). Eighteen of the 19 patients underwent direct microsurgical removal of the space occupying lesion using the transcortical-transventricular approach. One patient had placement of a ventriculoperitoneal shunt and declined further treatment. There were no deaths in the entire series and no permanent neurological deficits were observed postoperatively. Surgery was successful in unblocking CSF pathways in 12 patients; six patients required permanent CSF diversion. Considering the advantages and disadvantages of various surgical modalities for the treatment of the lesions we recommend the microsurgical removal of the colloid cyst using the transcortical-transventricular approach.     

Magnetic source imaging and brain surgery: presurgical and intraoperative planning in 26 patients

OBJECT: The availability of large-array biomagnetometers has led to advances in magnetoencephalography that permit scientists and clinicians to map selected brain functions onto magnetic resonance images. This merging of technologies is termed magnetic source (MS) imaging. The present study was undertaken to assess the role of MS imaging for the guidance of presurgical planning and intraoperative neurosurgical technique used in patients with intracranial mass lesions. METHODS: Twenty-six patients with intracranial mass lesions underwent a medical evaluation consisting of MS imaging, a clinical history, a neurological examination, and assessment with the Karnofsky Performance Scale. Magnetic source imaging was used to locate the somatosensory cortex in 25 patients, the visual cortex in six, and the auditory cortex in four. The distance between the lesion and the functional cortex was determined for each patient. Twenty-one patients underwent a neurosurgical procedure. As a surgical adjunct, a frameless stereotactic navigational system was used in 17 cases and a standard stereotactic apparatus in four cases. Because of the results of their MS imaging examination, two patients were not offered surgery, four underwent a stereotactic biopsy procedure, 10 were treated with a subtotal surgical resection, and seven were treated with complete surgical resection. One patient deteriorated before a procedure could be scheduled and, therefore, was not offered surgery, and two patients were offered surgery but declined. Three patients experienced surgery-related complications. CONCLUSIONS: Magnetic source imaging is an important noninvasive neurodiagnostic tool that provides critical information regarding the spatial relationship of a brain lesion to functional cortex. By providing this information, MS imaging facilitates a minimum-risk management strategy and helps guide operative neurosurgical technique in patients with intracranial mass lesions.     

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).     

Open stereotactic selective amygdalo-hippocampectomy for drug resistant epilepsy

Summary Selective removal of the medio-basal temporal structures has been introduced as an alternative to standard temporal lobectomy in the treatment of intractable temporal lobe epilepsy not related to gross structural lesions. Various approaches have been described for the surgical excision of the amygdalo-hippocampal complex, each of them presenting advantages and limitations.The recently introduced computer-assisted technique of volumetric stereotactic excision of deep-seated intracerebral lesions combines precision of targeting with elimination of unnecessary cortical trauma and may potentially provide an alternative method in the treatment of temporal lobe epilepsy.We present our experience of stereotactic volumetric selective amygdalo-hippocampectomy in six patients with medically intractable temporal lobe epilepsy. The criteria for selection, the pre-operative evaluation and the operative technique are discussed. All patients had a cessation or considerable reduction in seizure frequency while the morbidity was minimal.Invited Lecture presented at the European Congress of Neurosurgery, Moscow, June 23–29, 1991.     

Interventional MRI-guided stereotactic aspiration of acute/subacute intracerebral hematomas

Surgical interventions for hypertensive intracerebral hematomas are still controversial. Many believe only hyperacute intervention is of any real utility. The majority of present interventions require a formal craniotomy with standard neurosurgical techniques. There are, however, a few reports on CT-guided stereotactic aspiration of these hematomas with favorable results. We report 10 patients treated with frameless fiduciless stereotactic means using an intraoperative MRI scanner (GE 0.5 T Signa SP). These patients were initially diagnosed as having hypertensive intracerebral hematoma and operated on within 1-34 days after hemorrhage. The actual operating time averaged less than 120 min, including intraoperative imaging. Clot volumes ranged from 2.5 to 75 cm(3) with a mean of 31 cm(3). There were 2 thalamic hematomas and 8 basal gangliar hematomas. Three patients had intraventricular hematoma extension and all 3, as well as an additional patient, required extraventricular drainage. However, no patients required permanent posthemorrhage ventriculoperitoneal shunting. Aspiration was successful in all cases to 70-90% of clot removal. Two cases utilized intrahematoma t-PA infusion with subsequent 80-90% clot removal. There were no complications or rehemorrhages. All patients showed some form of improvement that included either improved blood pressure control, speech or cognitive abilities. We conclude that using an intraoperative MRI scanner to perform frameless, fiduciless stereotactic aspiration of acute/subacute intracerebral hematoma is a safe and potentially effective means of treating intracerebral hematomas.