Transient Ageusia and Dysgeusia Following Thalamic Cyst Drainage.

Taste consists of sensation and perception. Specific neural structures transmit a stimulus from the taste buds to the gustatory cortex to generate taste sensation. Any disruption of this pathway, whether it affects sensation or perception, can result in taste disorders. Stereotactic procedures involving the thalamus may result in gustatory complications. A 41-year-old female patient who underwent stereotactic drainage of a thalamic cyst suffered transient ageusia. Subsequently, she developed metallic taste perception. When her stereotactic plan was re-evaluated, it was noted that the posteromedial ventral thalamus nucleus was in the path of the needle tract and the needle had passed through it. Follow-up was recommended and her symptoms completely resolved within 2 months following surgery. Modern imaging techniques allow for the visualization of neural structures related to the sense of taste. Additionally, care must be taken when planning stereotactic procedures for such lesions.

Clinical efficacy and safety of neuroendoscopic surgery for severe thalamic hemorrhage with ventricle encroachment.

To summarize and analyze the clinical efficacy and safety of neuroendoscopic surgery (NES) in the treatment of patients for severe thalamic hemorrhage with ventricle encroachment (THVE). Eighty-three patients with severe THVE were treated in the Neurosurgery Department of Anqing Hospital Affiliated to Anhui Medical University from July 2019 to August 2021. Our study was approved by the ethics committee. The patients were randomly divided into NES group and extraventricular drainage (EVD) group. The hospital stay, Glasgow coma scale (GCS) scores on the 1st and 14th days postoperatively, the incidence of intracranial infections, and the clearance of postoperative hematomas were compared and analyzed between the two groups. The patients had follow-up evaluations 6 months postoperatively. The prognosis was evaluated based on the activity of daily living (ADL) score. A head CT or MRI was obtained to determine whether there was hydrocephalus, cerebral infarction, or other related complications. Eighty-three patients were randomly divided into 41 cases of NES group and 42 cases of EVD group. The length of postoperative hospital stay was 17.42 ± 1.53 days, the GCS scores were 6.56 ± 0.21, and 10.83 ± 0.36 on days 1 and 14, respectively; intracranial infections occurred in 3 patients (7.31%) and the hematoma clearance rate was 83.6 ± 5.18% in the NES group, all of which were significantly better than the EVD group (P < 0.05). After 6 months of follow-up, 28 patients (68.29%) had a good prognosis, 5 patients (12.19%) died, and 4 patients (9.75%) had hydrocephalus in the NES group. In the EVD group, the prognosis was good in 15 patients (35.71%), 12 patients (28.57%) died, and 17 patients (40.47%) had hydrocephalus. The prognosis, mortality rate, and incidence of hydrocephalus in the NES group were significantly better than the EVD group (P < 0.05). Compared to traditional EVD, NES for severe THVE had a higher hematoma clearance rate, and fewer intracranial infections and patients with hydrocephalus, which together improve the clinical prognosis and is thus recommended for clinical use.

Endoscopic-Assisted Translateral Ventricular Transchoroidal Fissure Approach for Evacuation of Medial-Type Thalamic Hemorrhage: Case Series.

BACKGROUND: Although surgeries for intracerebral hemorrhage remain controversial, endoscopic surgery is considered a promising surgical treatment. The most fatal type of thalamic hemorrhage is the medial type, which is always combined with expansion of the hematoma into the third ventricle. The current endoscopic approach to this lesion involves injury to the mediodorsal nucleus of the thalamus (MDT). CASE DESCRIPTION: We report 5 cases of medial thalamic hemorrhage with third intraventricular involvement treated by an endoscopic-assisted translateral ventricular transchoroidal fissure approach. The preoperative average volume of the parenchymal hematomas was 9.63 mL, while the preoperative average volume of the intraventricular hematomas was 23.35 mL. The average surgical duration was 80.6 minutes. No intraoperative MDT incision was needed in any patient. The evacuation rates of parenchymal and intraventricular hematomas were 74.21%-98.84% and 85.89%-99.51%, respectively. Three months after the surgery, the average Glasgow Coma Scale scores improved to 13.8 from 7.2 preoperatively. No ventriculoperitoneal shunt was needed in any patient. CONCLUSIONS: The endoscopic-assisted translateral ventricular transchoroidal fissure approach is a safe and effective approach for evacuation of a medial thalamic hemorrhage with third intraventricular involvement. This approach allows parenchymal hematoma evacuation through the rupture of the third ventricle without incising the MDT in the lateral ventricle.

Different surgical interventions for patients with spontaneous supratentorial intracranial hemorrhage: A network meta-analysis.

OBJECTIVE: This study was performed to explore the efficacy and safety of different surgical interventions in patients with spontaneous supratentorial intracranial hemorrhage (SSICH) and determine which intervention is most suitable for such patients. PATIENTS AND METHODS: We searched the PubMed, Medline, OVID, Embase, and Cochrane Library databases. The quality of the included studies was assessed. Statistical analyses were performed using the software Stata 13.0 and RevMan 5.3. RESULTS: Endoscopic surgery (ES), minimally invasive surgery combined with urokinase (MIS + UK), minimally invasive surgery combined with recombinant tissue plasminogen activator (MIS + rt-PA), and craniotomy were associated with higher survival rates and a lower risk of intracranial rebleeding than standard medical care (SMC) in patients with SSICH, especially in younger patients with few comorbidities. The order from highest to lowest survival rate was ES, MIS + UK, MIS + rt-PA, craniotomy, and SMC. The order from lowest to highest intracranial rebleeding risk was ES, MIS + UK, craniotomy, MIS + rt-PA, and SMC. Additionally, compared with SMC, all four surgical interventions (ES, MIS + rt-PA, MIS + UK, and craniotomy) improved the prognosis and reduced the proportion of patients with serious disability. The order from most to least favorable prognosis was MIS + rt-PA, ES, MIS + UK, craniotomy, and SMC. The order from highest to lowest proportion of patients with serious disability was ES, MIS + rt-PA, MIS + UK, craniotomy, and SMC. CONCLUSIONS: This study revealed that the efficacy and safety of different surgical interventions (ES, MIS + UK, MIS + rt-PA, craniotomy) were superior to those of SMC in the patients with SSICH, especially in younger patients with few comorbidities. Among them, ES was the most reasonable and effective intervention. ES was found not only to improve the survival rate and prognosis but also to have the lowest risk of intracranial rebleeding and the lowest proportion of patients with serious disability.

Efficacy Analysis of Robot-Assisted Minimally Invasive Surgery for Small-Volume Spontaneous Thalamic Hemorrhage.

OBJECTIVE: To test whether robot-assisted surgery can improve prognosis of small-volume thalamic hemorrhage and to provide a surgical basis for treatment of small-volume thalamic hemorrhage. METHODS: This retrospective study included patients with thalamic hemorrhage and hematoma volume of 5-15 mL treated from December 2015 to December 2018. Patients were divided into an operation group and a nonoperation group. General data, types of hematoma, incidence of complications, Scandinavian Stroke Scale score, and modified Rankin Scale score were recorded and analyzed. RESULTS: Retrospectively, 84 cases met inclusion criteria: 35 cases in operation group and 49 cases in nonoperation group. At 90 days after onset, mortality was 11.4% in the operation group and 4.1% in the nonoperation group (P > 0.05). The Scandinavian Stroke Scale score in the operation group (43.3 ± 8.5) was higher than in the nonoperation group (36.1 ± 10.0) (P < 0.05). The modified Rankin Scale score in the operation group (2.9 ± 0.3) was lower than in the nonoperation group (3.7 ± 0.2) (P < 0.05). The incidence of pneumonia (8.6%) and renal dysfunction (14.3%) was lower in the operation group than in the nonoperation group (28.6% and 34.7%, respectively) (P < 0.05). There was no significant difference between the 2 groups in the incidence of central fever (5.7% vs. 12.2%), stress ulcer (11.4% vs. 16.3%), and ion balance disturbance (20.0% vs. 26.5%) (P > 0.05). CONCLUSIONS: Robot-assisted drainage of thalamic hemorrhage can improve prognosis and reduce the incidence of pneumonia and renal dysfunction.

Dorsal anterior cingulate cortex (ACC) deep brain stimulation (DBS): a promising surgical option for the treatment of refractory thalamic pain syndrome (TPS).

BACKGROUND: Neuroimaging evidences and previous successful case series of cingulotomy for cancer pain have disclosed the key-role of the dorsal anterior cingulate cortex (ACC) in the generation of the empathic and affective dimension of pain. The aim of this study is to assess the effectiveness and safety of ACC neuromodulation for the treatment of the thalamic pain syndrome (TPS), a chronic neuropathic disease often complicated by severe affective and emotional distress in the long term. METHOD: From January 2015 to April 2017, 5 patients with pure drug-refractory TPS underwent ACC deep brain stimulation (DBS) at our institution. Quantitative assessment of pain and health-related quality of life were performed 1 day before surgery and postoperatively at 6 and 18 months by using the numeric rating scale (NRS), the 36-item short-form health survey (SF-36), and the McGill pain and the EuroQol5-domain questionnaires. RESULTS: Mean age at surgery was 56.2 years (range, 47-66). NRS score improved by 37.9% at 6 months (range, - 22.2 to - 80%) and by 35% at 18 months (range, - 11.1 to - 80%). At the last follow-up, one patient reported a relevant pain reduction (NRS 2), only complaining of mild pain poorly interfering with activities of daily living. Concomitant improvements in the McGill and EuroQol5-domain pain questionnaires, SF-36 total and sub-item scores were also noticed at each follow-up. No surgical or stimulation-related complications occurred during the study period. CONCLUSIONS: ACC DBS may be a safe and promising surgical option to alleviate discomfort and improve the overall quality of life in a patient affected by drug-resistant TPS. Further prospective, larger, and randomized studies are needed to validate these findings.

Recurring Thalamic Symptoms Due to Intracranial Dural Arteriovenous Fistula: Report of Unusual Case and Treatment Outcome.

BACKGROUND: Initial clinical presentation of dural arteriovenous fistula (DAVF) with predominantly thalamic symptoms is rare and has not been reported until now. CASE DESCRIPTION: A young child presenting with complaints of tinnitus and mild right hemiparesis was evaluated with an initial magnetic resonance imaging, which revealed a Borden type 2 DAVF in the right transverse sinus with retrograde venous drainage and cortical venous reflux. Flow-related small aneurysms were also noted in the left basal vein of Rosenthal (BVR). Two days later, his motor power deteriorated and he developed right hemisensory loss and severe thalamic pain. Aphasia was atypical and mimicked the transcortical type. Repeat imaging revealed expanding thrombosed aneurysm of BVR with mass effect and edema on thalamocapsular region. Initial antiedema measures reversed the neurologic deficits; however, they recurred, necessitating an urgent endovascular intervention. Angiogram revealed an extensive high-flow DAVF in the right transverse-sigmoid sinus and torcula with preferential retrograde venous drainage into deep veins and left BVR. He underwent staged embolization of DAVF, resulting in significant obliteration of shunt. Neurologic deficits improved in the postoperative period, and the patient remained clinically asymptomatic at 6 months of follow-up. CONCLUSIONS: DAVF presenting with recurrent predominantly thalamic symptoms is rare. Atypical transcortical aphasia rather than fluent aphasia is an unusual clinical manifestation of thalamic pathology and could result from the involvement of specific thalamic nuclei. Preferential high flow into BVR in the presence of venous anomalies could potentially induce architectural weakness of the venous wall and precipitate aneurysm formation. Embolization of the DAVF can potentially reverse this unusual neurologic condition.

Tractography guides the approach for resection of thalamopeduncular tumors.

BACKGROUND: Thalamopeduncular tumors arise at the junction of the inferior thalamus and cerebral peduncle, and present with a common clinical syndrome of progressive spastic hemiparesis. METHOD: Formal preoperative magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were performed. Postoperative MRI was obtained to evaluate the extent of tumor resection. A prospective analysis of clinical outcomes was then conducted by the senior author. CONCLUSIONS: Preoperative tractography is a useful adjunct to surgical planning in tumors that displace motor pathways. Gross total resection of pilocytic astrocytomas usually results in cure, and therefore should be entertained when developing treatment strategies for thalamopeduncular tumors of childhood.

Third Ventricular Cerebrospinal Fluid Cysts of Thalamic Origin: Review of Embryologic Origin, Presentation, and Management Strategies with a Case Series.

OBJECTIVE: Third ventricular cerebrospinal fluid (CSF) cysts of thalamic origin are rare. The objective of this study is to review their possible pathogenesis, clinical presentation, and management strategies with a case series describing management via an endoscopic approach with fenestration using a single burr-hole technique. METHODS: A systematic literature review of reported cases of thalamic cysts was conducted with further meta-analysis of CSF cysts that involve the third ventricle. The mode of presentation, pathologic analysis, surgical management, and outcomes were analyzed. RESULTS: Twenty-two studies reported between 1990 and 2013 described 42 cases of thalamic cyst. Of those cases, 13 were consistent with CSF cyst that originated in the thalamus and involved the third ventricle. Eight cases (61.5%) were treated via endoscopic fenestration, 2 cases (15.4%) were surgically drained, 2 cases (15.4%) were stereotactically aspirated, and 1 case (7.69%) was observed. The most common presenting symptoms were gait disturbance (26.3%) and headaches (26.3%) followed by tremors (15.8%) and weakness (15.8%). In our series, a single burr-hole technique was a successful definitive treatment, with an average period of 23 months. CONCLUSIONS: Third ventricular CSF cysts of thalamic origin most commonly present with hydrocephalus. They can be safely definitively treated via endoscopic fenestration to the CSF circulation using a single burr-hole technique. Long-term follow-up shows lasting improvement in symptoms without reaccumulation of the cyst.

Distant recurrences limit the survival of patients with thalamic high-grade gliomas after successful resection.

The indications of surgery for thalamic high-grade gliomas are not well established. The present study investigated the outcome of 21 patients treated by surgery and reports the high incidence of distant recurrences including disseminations after successful removal. Twenty-one patients with thalamic high-grade gliomas not invading the pyramidal tract or midbrain underwent cytoreductive surgery at our institute from June 1997 to August 2015. Surgery was performed with the aid of a neuronavigation system, electrophysiological monitoring, and fluorescence navigation. Tumor histology included 12 cases of the World Health Organization grade III and nine cases of grade IV. Gross total resection was achieved in six cases, subtotal in 13, and partial in two. Motor weakness accompanied by sensory disturbance deteriorated immediately after surgery in 13 patients. However, five patients were determined to show deterioration at 2 months after surgery. Postoperative radiation and chemotherapy were given to every patient, and median progression-free survival of patients with grade III and IV tumors was 12.1 and 7.0 months, respectively. Median overall survival of patients with grade III and IV tumors was 25.6 and 12.6 months, respectively. High incidence of distant recurrences was found, with distant lesions at recurrence in 13 of 19 patients with recurrence, suggesting the life-restricting factor in these patients. Thalamic high-grade glioma without invasion into the pyramidal tract and brainstem can be considered as a candidate for surgical resection. Distant lesion limits the survival of patients after successful resection.

Occipital transtentorial/falcine approach, a "cross-court" trajectory to accessing contralateral posterior thalamic lesions: case report.

Surgical treatment of lesions in the posterior thalamus, especially those extending laterally, is technically challenging because of a deep surgical field, narrow operative corridor, and the surrounding critical neurovascular structures. The authors describe an occipital transtentorial/falcine approach (OTFA) that was successfully used in the treatment of a cavernous malformation (CM) extending laterally from thalamus to midbrain. A 40-year-old man complained of progressive right hemiparesis and numbness. Radiological evaluation revealed a large CM in the left thalamus, surfacing on the pulvinar thalami, and extending 4 cm laterally from the midline. In addition to the usual procedures of a right-sided occipital transtentorial approach, the authors incised the falx cerebri to expand the operative corridor to the left thalamus. They achieved generous exposure of the left thalamus through a "cross-court" oblique trajectory while avoiding excessive retraction on the occipital lobe. The CM was completely removed, and no newly developed or worsening deficits were detected postoperatively. To better understand the OTFA and its application, the authors performed a cadaveric dissection. The OTFA provides increased exposure of the posterior thalamus without cortical incision and facilitates lateral access to this area through the "cross-court" operative corridor. This approach adds to the armamentarium for neurosurgeons treating thalamic lesions.

High-Definition Fiber Tractography in Evaluation and Surgical Planning of Thalamopeduncular Pilocytic Astrocytomas in Pediatric Population: Case Series and Review of Literature.

OBJECTIVE: Thalamopeduncular tumors (TPTs) of childhood present a challenge for neurosurgeons due to their eloquent location. Preoperative fiber tracking provides total or near-total resection, without additional neurologic deficit. High-definition fiber tractography (HDFT) is an advanced white matter imaging technique derived from magnetic resonance imaging diffusion data, shown to overcome the limitations of diffusion tensor imaging. We aimed to investigate alterations of corticospinal tract (CST) and medial lemniscus (ML) caused by TPTs and to demonstrate the application of HDFT in preoperative planning. METHODS: Three pediatric patients with TPTs were enrolled. CSTs and MLs were evaluated for displacement, infiltration, and disruption. The relationship of these tracts to tumors was identified and guided surgical planning. Literature was reviewed for publications on pediatric thalamic and TPTs that used diffusion imaging. RESULTS: Two patients had histologic diagnosis of pilocytic astrocytoma. One patient whose imaging suggested a low-grade glioma was managed conservatively. All tracts were displaced (1 CST anteriorly, 2 CSTs, 1 ML anteromedially, 1 ML medially, and 1 ML posteromedially). Literature review revealed 2 publications with 15 pilocytic astrocytoma cases, which investigated CST only. The condition of sensory pathway or anteromedial displacement of the CST in these tumors was not reported previously. CONCLUSIONS: Displacement patterns of the perilesional fiber bundles by TPTs are not predictable. Fiber tracking, preferably HDFT, should be part of preoperative planning to achieve maximal extent of resection for longer survival rates in this young group of patients, while preserving white matter tracts and thus quality of life.

Acute bithalamic infarct manifesting as sleep-like coma: A diagnostic challenge.

Bilateral thalamic infarction (BTI) typically presents as a sleep-like coma (SLC) without localizing signs, posing a diagnostic challenge that may lead the treating physician to search for toxic or metabolic causes and delay treatment. We review our experience with BTI of different etiologies, and emphasize the critical role of timely imaging, diagnosis, and management in a series of 12 patients with a presentation of SLC and acute BTI who were managed in our Medical Centers from 2006-2015. In 11/12, urgent head CT scans showed normal brain tissue, while diffusion-weighted (DWI) MRI revealed symmetric bilateral thalamic hyperintense lesions with variable degrees of brainstem involvement. In 1/12, CT scans revealed a contralateral subacute stroke from a thalamic infarct 1month earlier with a unilateral hyperintense lesion on DWI-MRI. From clinical and imaging findings (DWI-MRI, CT angiography and venography), etiology was attributed to embolic causes (cardio-embolism, artery-to-artery mechanism), small vessel disease, or deep sinus vein thrombosis secondary to dural arteriovenous (AV) fistula. Three patients had good outcomes after prompt diagnosis and optimal treatment in <3hours (intravenous tissue plasminogen activator in two patients cardio-embolic etiology and neuro-endovascular repair in one patient with venous infarction due to a dural AV fistula). The diagnosis was made beyond the therapeutic window in seven patients, who were left with significant neurological sequelae. Higher awareness of BTI presenting as SLC is warranted. Optimal patient management includes urgent DWI-MRI. In cases of BTI, further imaging workup is indicated to provide a comprehensive assessment for etiology. Early diagnosis and prompt, targeted intervention are crucial.

Role of Intraoperative Neurophysiologic Monitoring in the Resection of Thalamic Astrocytomas.

BACKGROUND: The thalamus is a deep-seated and crucial structure for the sensorimotor system. It has been long considered a surgically inaccessible area because of the morbidity associated with surgical resections. Astrocytomas of the thalamus are usually treated with bioptic procedures followed by adjuvant treatments. Intraoperative neurophysiologic monitoring (IONM) allows safe and satisfactory resections of lobar gliomas, but few data are available for thalamic lesions. The aim of this study was to review the outcome of a small series of patients with thalamic astrocytomas that were treated with surgical resection with the aid of IONM. METHODS: Surgical resection with IONM was performed in 5 patients with thalamic astrocytomas (1 grade I, 1 grade II, 2 grade III, 1 grade IV). Two astrocytomas were in the dominant hemisphere. Preoperative and postoperative neuropsychological assessments were performed in 3 patients. IONM was tailored to the individual patient and consisted of transcranial motor evoked potential monitoring, cortical motor evoked potential monitoring, somatosensory evoked potential monitoring, direct electrical stimulation, electroencephalography, and electrocorticography. RESULTS: None of the patients experienced permanent motor deficits; 2 patients had a transient hemiparesis requiring rehabilitation; 1 patient had a transient aphasia, and 1 patient had permanent aphasia. None of the patients had intraoperative seizures, but 1 patient experienced postoperative transient status epilepticus. The extent of resection on postoperative volumetric magnetic resonance imaging was >70% in all cases. CONCLUSIONS: Surgical resection of thalamic astrocytomas appeared to be effective and relatively safe when guided by IONM. Larger series of patients are required to confirm these preliminary data.

Improved outcome of patients with severe thalamic hemorrhage treated with cerebrospinal fluid drainage and neurocritical care during 1990-1994 and 2005-2009.

INTRODUCTION: Patients with thalamic hemorrhage, depressed level of consciousness and/or signs of elevated intracranial pressure may be treated with neurocritical care (NCC) and external ventricular drainage (EVD) for release of cerebrospinal fluid. METHODS: Forty-three patients with thalamic hemorrhage treated with NCC from 1990 to 1994 (n = 21) and from 2005-2009 (n = 22) were evaluated. Outcome was assessed using the Glasgow Coma Scale (GCS) score at discharge from our unit and the modified Rankin Scale (mRS) for long-term outcome. RESULTS: Patients' age was 59.5 ± 7 years in 1990-1994, and 58.2 ± 9 years in 2005-2009. The median (25th and 75th percentile) GCS score on admission for the two time periods was 9 (6-12) and 9 (4-14), respectively. Long-term follow-up was assessed at a mean of 37.1 (range 19-65) months after disease onset for the 1990-1994 cohort and at 37.4 (range 14-58) months for the 2005-2009 cohort. Compared to patients from 1990 to 1994, patients from 2005 to 2009 had a significantly better outcome (median mRS [25th and 75th percentile]: 5 [4-6] vs. 4 [2-4.5]; p < 0.01). Most patients (13/21, 62 %) treated from 1990 to 1994 had unchanged or lower GCS scores during their NCC stay in contrast to 7/22 (32 %) from 2005 to 2009. At the last follow-up, 13/21 (62 %) patients from 1990 to 1994 were dead in comparison to 4/21 (19 %) from 2005 to 2009 (p < 0.05). Negative prognostic factors were the 120 h post-admission GCS score in the 1990-1994 patient cohort (p = 0.07) and high age in the recent cohort (p = 0.04). CONCLUSIONS: Patients with thalamic hemorrhage and depressed level of consciousness on admission had a worse outcome in the early 1990s compared with the late 2000s, which may at least be partially attributed to refined neurocritical care.

Spontaneous thalamic hemorrhage from a lateral posterior choroidal artery aneurysm.

BACKGROUND: The authors report a case of lateral posterior choroidal artery pseudoaneurysm that caused a spontaneous thalamic hemorrhage. The case supports obtaining computed tomographic angiography (CTA) even in seemingly routine cases of hypertensive hemorrhage and demonstrates a possibly unreported type of aneurysm causing thalamic hemorrhage. CASE DESCRIPTION: A 60-year-old man with a history of hypertension presented with a spontaneous right thalamic hemorrhage, and CTA showed a focus of contrast inside the hematoma. One month later, the patient was well but a CTA showed that the hematoma had resolved but that there was enlargement of the contrast-enhancing lesion in the thalamus. Catheter angiography showed an aneurysm of the lateral posterior choroidal artery. This was excised via an occipital interhemispheric supratentorial subcallosal approach. The patient recovered fully and returned to work 3 months later. CONCLUSION: The case shows the need to carefully review CTA after ICH, even in cases of seemingly typical hypertensive ICH.

Surgical management of thalamic gliomas: case selection, technical considerations, and review of literature.

This study aimed to identify (1) the thalamic gliomas suitable for surgical resection and (2) the appropriate surgical approach based on their location and the displacement of the posterior limb of the internal capsule (PLIC). A retrospective study over a 5-year period (from 2006 to 2010) was performed in 41 patients with thalamic gliomas. The mean age of these patients was 20.4 years (range, 2-65 years). Twenty (49 %) tumors were thalamic, 19 (46 %) were thalamopeduncular, and 2 (5 %) were bilateral. The PLIC, based on T2-weighted magnetic resonance axial sections, was displaced anterolaterally in 23 (56 %) cases and laterally in 6 (14 %) cases. It was involved by lesion in eight (20 %) cases and could not be identified in four (10 %) cases. Resection, favored in patients with well-defined, contrast-enhancing lesions, was performed in 34 (83 %) cases, while a biopsy was resorted to in 7 (17 %) cases. A gross total resection or near total resection (>90 %) could be achieved in 26 (63 %) cases. The middle temporal gyrus approach, used when the PLIC was displaced anterolaterally, was the commonly used approach (63.5 %). Common pathologies were pilocytic astrocytoma (58 %) in children and grade III/IV astrocytomas (86 %) in adults. Preoperative motor deficits improved in 64 % of the patients with pilocytic lesions as compared to 0 % in patients with grade III/IV lesions (P value, 0.001). Postoperatively, two patients (5 %) had marginal worsening of motor power, two patients developed visual field defects, and one patient developed a third nerve paresis. Radical resection of thalamic gliomas is a useful treatment modality in a select subset of patients and is the treatment of choice for pilocytic astrocytomas. Tailoring the surgical approach, depending on the relative position of the PLIC, has an important bearing on outcome.

Utility of the CO2 laser in the microsurgical resection of cavernous malformations.

OBJECTIVE: The CO2 laser has a long record of use in neurosurgery. However, its utility has been limited by its bulky design and the challenge of using it with the operating microscope. With the development of the OmniGuide fiber, a technology that delivers the beam through flexible hollow-core photonic bandgap mirrors, the laser can now be held and used with greater ease and accuracy. METHODS: We retrospectively analyzed a prospectively maintained database to assess the utility of the laser in 23 consecutive patients (10 male, 13 female; mean age, 40.8 years; range, 9-64 years) with a cavernous malformation treated by the senior author (R.F.S.). RESULTS: Four lesions were located in noneloquent areas, 13 were in the brain stem, four were in the spinal cord, and two were in the thalamus. The usefulness of the laser was rated on a scale of 1 to 5, with 5 defined as "extremely helpful." The mean utility score was 3.5 ± 0.94 (range, 2-5). The laser was judged most useful in creating cortisectomies in eloquent areas and in "shrinking" cavernous malformations away from adjacent hemosiderin-stained tissue. The laser was ineffective against calcification and in obtaining hemostasis. CONCLUSIONS: The CO2 laser is a useful addition to the neurosurgical armamentarium for treating lesions in the brainstem, thalamus, and spinal cord. Its primary utility lies in its ability to create focused cortisectomies safely and to shrink cavernous malformations away from eloquent hemosiderin-stained brain.