Neurosurgery Blog

Neurosurg Focus 31 (6):E4, 2011. DOI: 10.3171/2011.9.FOCUS11237

The management of incidental small unruptured intracranial aneurysms (UIAs) is controversial and many factors need to be considered in the decision-making process. The authors describe a large consecutive series of patients harboring small incidental intracranial aneurysms. Treatment strategy, natural history, complications, and short-term outcomes are presented.

Methods. Between January 2008 and May 2011, the authors prospectively evaluated 212 patients with 272 small (< 10-mm) incidental aneurysms. Treatment recommendations (observation, endovascular treatment, or surgery), complications of treatment, and short-term outcomes were assessed.

Results. Recommended treatment consisted of observation in 125 patients, endovascular embolization in 64, and surgery in 18. Six patients were excluded from further analysis because they underwent treatment elsewhere. In the observation group, at a mean follow-up of 16.7 months, only 1 patient was moved to the embolization group. Seven (6%) of the 125 patients in the observation group died of causes unrelated to aneurysm. Sixty-five patients underwent 69 embolization procedures. The periprocedural permanent morbidity and mortality rates in patients undergoing endovascular treatment were 1.5% and 1.5%, respectively (overall morbidity and mortality rate 3.0%). In the surgery group no periprocedural complications were observed, although 1 patient did not return to her previous occupation. No aneurysmal rupture was documented in any of the 3 treatment groups during the follow-up period.

Conclusions. A cautious and individualized approach to incidental UIAs is of utmost importance for formulation of a safe and effective treatment algorithm. Invasive treatment (either endovascular or surgery) can be considered in selected younger patients, certain “higher-risk” locations, expanding aneurysms, patients with a family history of aneurysmal hemorrhage, and in those who cannot live their lives knowing that they harbor the UIA. Although the complication rate of invasive treatment is very low, it is not negligible. The study confirms that small incidental UIAs deemed to be not in need of treatment have a very benign short-term natural history, which makes observation a reasonable approach in selected patients.

Neurosurgery 69[ONS Suppl 2]:ons121–ons140, 2011. DOI: 10.1227/NEU.0b013e31822a547b

Schwannomas originating from the hypoglossal nerve are extremely rare. Microsurgical resection with the goal for cure has traditionally been associated with a high risk of postoperative deficits.

OBJECTIVE: To summarize our clinical experience using tailored cranial base approaches for these formidable lesions.

METHODS: The clinical records of 13 patients were retrospectively reviewed. In addition, all reported patients in the literature were reviewed. The extreme lateral infrajugular transcondylar-transtubercular exposure approach was used in all of our patients. Based on our experience and literature analysis, we propose the following modified grading scale to facilitate surgical planning: type A, intradural tumors; type B, dumbbell-shaped tumors; type C, extracranial tumors; and type D, peripheral tumors.

RESULTS: All 13 patients underwent total, near-total, or subtotal tumor resection. Eight patients were men, 5 were women (mean age, 41.7 years). Sural nerve graft reconstruction for the hypoglossal nerve was performed in 4 patients. Three of the 4 patients in whom nerve reconstruction was performed regained satisfactory movement of their tongue. In the review of the literature, the mean patient age was 45.8 years. Patients presented with tongue atrophy (91.6%), headache (60.9%), and dysphagia (31.8%). The tumors were categorized as type A in 31.7% of these patients, type B in 38.6%, type C in 6.2%, and type D in 23.4%.

CONCLUSION: The extreme lateral infrajugular transcondylar-transtubercular exposure approach, which is a modification of the extreme lateral suboccipital approach, provides sufficient exposure for most intracranial dumbbell-shaped hypoglossal schwannomas. Hypoglossal nerve reconstruction using a sural nerve graft improves tongue atrophy and movement for patients with resected nerves.

Neurosurgery 69:1116–1123, 2011 DOI: 10.1227/NEU.0b013e31822932fe
Traditional treatment options for optic nerve sheath meningiomas (ONSMs) include observation, surgery, and radiotherapy, but to date none of these has become the clear treatment of choice.
OBJECTIVE: To evaluate the effectiveness and safety of multisession radiosurgery for ONSMs.
METHODS: From May 2004 to June 2008, 21 patients with ONSMs were treated by radiosurgery using the frameless CyberKnife system. Patient age ranged from 36 to 73 years (mean, 54 years). All patients were treated using multisession radiosurgery, with 5 fractions of 5 Gy each to a total dose of 25 Gy prescribed to the 75% to 85% isodose line. Patients were evaluated for tumor growth control and visual function.
RESULTS: The median pretreatment tumor volume was 2.8 mL (range, 0.3-23 mL). The mean follow-up was 30 months (range, 11-68 months). All patients tolerated treatment well, with only 1 patient in whom a mild optic neuropathy developed (which remitted after systemic steroid therapy). No other acute or late radiation-induced toxicities were observed. No patients showed ONSM progression on follow-up magnetic resonance imaging. Two patients (10%) had a partial response. No patients had worsening of visual function; visual function was stable in 65% and improved in 35% of patients.
CONCLUSION: Multisession radiosurgery for ONSMs was found to be safe and effective. The preliminary results from this study, in terms of growth control, visual function improvement, and toxicity, are quite promising. Further investigations are warranted.

J Neurosurg 115:900–905, 2011. DOI: 10.3171/2011.7.JNS102092

Preservation of cochlear nerve function in vestibular schwannoma (VS) removal is usually dependent on tumor size and preoperative hearing status. Tumor origin as an independent factor has not been systematically investigated.

Methods. A series of 90 patients with VSs, who underwent surgery via a suboccipitolateral route, was evaluated with respect to cochlear nerve function, tumor size, radiological findings, and intraoperatively confirmed tumor origin. All patients were reevaluated 12 months after surgery.

Results. Despite comparable preoperative cochlear nerve status and larger tumor sizes, hearing preservation was achieved in 42% of patients with tumor originating from the superior vestibular nerve, compared with 16% of those with tumor originating from the inferior vestibular nerve.

Conclusions. Tumor origin is an important prognostic factor for cochlear nerve preservation in VS surgery.

Neurosurgery 69:1105–1115, 2011 DOI: 10.1227/NEU.0b013e318227e0e1

In patients with aneurysmal subarachnoid hemorrhage (SAH), preliminary results indicate that the amplitude of the single intracranial pressure (ICP) wave is a better predictor of the early clinical state and 6-month outcome than the mean ICP.

OBJECTIVE: To perform a randomized and blinded single-center trial comparing the effect of mean ICP vs mean ICP wave amplitude (MWA)-guided intensive care management on early clinical state and outcome in patients with aneurysmal SAH.

METHODS: Patients were randomized to 2 different types of ICP management: maintenance of mean ICP less than 20 mm Hg and MWA less than 5mm Hg. Early clinical state was assessed daily using the Glasgow Coma Scale. The primary efficacy variable was 12-month outcome in terms of the Rankin Stroke Score.

RESULTS: Ninety-seven patients were included in the study. There were no significant differences in treatment between the 2 groups apart from a larger volume of cerebrospinal fluid drained during week 1 in the MWA group. There was a tendency toward higher Glasgow Coma Scale scores in the MWA group during weeks 1 (P = .08) and 2 (P = .07). Outcome in terms of Rankin Stroke Score at 12 months was significantly better in the MWA group (P < .05).

CONCLUSION: This randomized and blinded trial disclosed a significant better primary efficacy variable (Rankin Stroke Score after 12 months) in the MWA patient group. We suggest that proactive intensive care management with MWA-tailored cerebrospinal fluid drainage during the first week improves aneurysmal SAH outcome.

Neurosurgery 69:1058–1069, 2011 DOI: 10.1227/NEU.0b013e318228bcea

Rathke cleft cysts (RCCs), benign remnants of the Rathke pouch typically arising in the sella, sometimes have suprasellar extension. Purely suprasellar RCCs are rarely reported.

OBJECTIVE: To compare the presentations, surgical outcomes, and pathology of purely suprasellar RCCs and sellar-based RCCs.

METHODS: We retrospectively reviewed records, magnetic resonance images, laboratory results, and pathology of 151 RCC patients surgically managed at our institution from 1989 to 2009. The RCCs were classified as purely sellar (type I, n = 76), sellar with suprasellar extension (type II, n = 56), or purely suprasellar (type III, n = 19).

RESULTS: The RCCs with a suprasellar component (types II and III) more commonly presented with visual dysfunction (P < .001). Complete cyst drainage occurred in 89%, 55%, and 38% of type I, II, and III RCCs, respectively (P < .001). Vision improved in 100%, 55%, and 33% and headache improved in 74%, 64%, and 29% of type I, II, and III patients, respectively (P = .02). Temporary or permanent postoperative diabetes insipidus occurred in 5%, 16%, and 21% of type I, II, and III patients, respectively. (P < .001). In a multivariate analysis, RCC type was the only factor predicting recurrence. Kaplan-Meier 3-year recurrence/progression rates were 0%, 16%, and 29% for type I, II, and III RCCs, respectively (P , .001, type I vs II, type I vs III; P = .5 type II vs III).

CONCLUSION: The RCCs with a suprasellar component are neurosurgically challenging because of their proximity to the optic chiasm and infundibulum. Compared with sellar-based RCCs, RCCs with a suprasellar component more frequently present with visual dysfunction, are more difficult to completely eliminate, recur more frequently, and are associated with higher postoperative endocrine morbidity, and their preoperative visual dysfunction and headache less frequently improve with surgery. These factors must be considered during the treatment of RCCs with a suprasellar component.

J Neurosurg 115:875–884, 2011. DOI: 10.3171/2011.6.JNS101958

In large vestibular schwannoma (VS), microsurgery is the main treatment option, and complete resection is considered the primary goal. However, previous studies have documented suboptimal facial nerve outcomes in patients who undergo complete resection of large VSs. Subtotal resection is likely to reduce the risk of facial nerve injury but increases the risk of lesion regrowth. Gamma Knife surgery (GKS) can be performed to achieve long-term growth control of residual VS after incomplete resection. In this study the authors report on the results in patients treated using planned subtotal resection followed by GKS with special attention to volumetric growth, control rate, and symptoms.

Methods. Fifty consecutive patients who underwent the combined treatment strategy of subtotal microsurgical removal and GKS for large VSs between 2002 and 2009 were retrospectively analyzed. Patients with neurofibromatosis Type 2 were excluded. Patient charts were reviewed for clinical symptoms. Audiograms were evaluated to classify hearing pre- and postoperatively. Preoperative and follow-up contrast-enhanced T1-weighted MR images were analyzed using volume-measuring software.

Results. Surgery was performed via a translabyrinthine (25 patients) or retrosigmoid (25 patients) approach. The median follow-up was 33.8 months. Clinical control was achieved in 92% of the cases and radiological control in 90%. One year after radiosurgery, facial nerve function was good (House-Brackmann Grade I or II) in 94% of the patients. One of the two patients who underwent surgery to preserve hearing maintained serviceable hearing after resection followed by GKS.

Conclusions. Considering the good tumor growth control and facial nerve function preservation as well as the possibility of preserving serviceable hearing and the low number of complications, subtotal resection followed by GKS can be the treatment option of choice for large VSs.

Neurosurgery 69:864–869, 2011 DOI: 10.1227/NEU.0b013e318222adfa

It is a prevalent myth that a postoperative infection may actually confer a survival advantage in patients with malignant glioma. This contention is based largely on anecdotal reports. Recently, a single-center study showed there was no survival advantage in those patients who had glioblastoma with postoperative infection.

OBJECTIVE: To examine the impact of postoperative infections on outcome in patients with glioblastoma treated at our center.

METHODS: This study included 197 patients with newly diagnosed primary glioblastoma treated from January 2001 to January 2008. Of the 197 patients, 10 (5.08%) had postoperative bacterial infection. The Kaplan-Meier method, log-rank test, and Breslow test were used in the univariate approach; Cox regression was used in the multivariable approach.

RESULTS: The median survival was 16 months (95% confidence interval [CI], 14-18 mo). The infection group had a significant advantage in the median survival: 30 months (95% CI, 21-39) vs 15 months (95% CI, 13-17) for patients without postoperative infection. This advantage was also confirmed by Cox regression; in fact, patients not developing a postoperative infection showed an adjusted hazard ratio for death of 2.3 (95% CI, 1-5.3).

CONCLUSION: The association between infection and prolonged survival is not definitive; we acknowledge the considerable difficulties in undertaking this type of study in a retrospective manner. Our results can instead stimulate further multicentric studies (to increase the number of patients) or experimental studies using genetically modified bacteria for treatment of glioblastoma.

Journal of Neurosurgery Oct 2011 / Vol. 115 / No. 4 / Pages 700-706

For oculomotor nerve palsy (ONP) induced by unruptured posterior communicating artery (PCoA) aneurysms, the authors performed surgical clipping via a superciliary keyhole approach as an optimal treatment modality with high efficiency and low invasiveness. In this study, they then evaluated the technical feasibility, safety, clinical outcomes, including recovery from ONP as well as cosmetic results, and durability of the procedure.

METHODS Thirteen patients presenting with complete (7 patients) or incomplete (6 patients) ONP underwent surgery via a superciliary approach. The operative video record was used to evaluate the technical feasibility, neurological examinations and CT were performed to analyze the safety of the treatment, and neuroophthalmological examinations and 3D CT angiography were undertaken to determine the effectiveness and durability of the treatment.

RESULTS In all cases, the aneurysms were successfully clipped using a 3.5-cm eyebrow incision and supraorbital minicraniotomy. The mean operative time was 108 ± 24 minutes. Twelve (92.3%) of the 13 patients showed complete resolution of the ONP. All 6 patients (100%) with incomplete ONP recovered completely within 1–2 months after surgery, whereas 6 (85.7%) of the 7 patients with complete ONP recovered completely within 1–6 months after surgery. Cosmetic results for the operative wounds were excellent without frontalis palsy. The durability of the treatment was ascertained based on 3D CT angiograms obtained 1 year after surgery.

CONCLUSIONS Surgical clipping via a superciliary keyhole approach can be an optimal treatment modality for PCoA aneurysms inducing ONP because it is effective, safe, and durable.

Eur Spine J (2011) 20:1684–1690. DOI 10.1007/s00586-011-1821-7
We present clinical findings, radiological characteristics and surgical modalities of various posterior approaches to thoracic disc herniations and report the clinical results in 27 consecutive patients. Within an 8-year period 27 consecutive patients (17 female, 10 male) aged 30–83 years (mean 53 years.) were surgically treated for 28 symptomatic herniated thoracic discs in our department. Six of these lesions (21%) were calcified. In all cases surgery was performed via individually tailored posterior approaches. We evaluated the pre- and postoperative clinical status and the complication rate in a retrospective study.
Nearly one half of the lesions (46.4%) were located at the three lowest thoracic segments. Clinical symptoms included back pain or radicular pain (77.8%), altered sensitivity (77.8%), weakness (40.7%), impaired gait (51.9%) or bladder dysfunction (22%). Costotransversectomy was performed in 8 patients, 1 lateral extracavitary approach, 2 foraminotomies, 15 transfacet and/or transpedicular approaches and 2 interlaminar approaches were used for removing the pathologies. After a mean follow-up of 38.6 months (3–100 months), complete normalization or reduction of local pain was recorded in 87%of the patients and of radicular pain in 70%of the cases, increased motor strength could be achieved in 55%, sensitivity improved in 76.2% and improvement of myelopathy was noted in 71.4%. Two patients suffered from postoperative impairment of sensory deficits, which in one case was discrete. The overall recovery rate within the modified JOA score was 39.5%. In 1 patient, two revisions were required because of instability and a persisting osteophyte, respectively. The rate of major complications was 7.1% (2/28).
Surgical treatment of thoracic disc herniations via posterior approaches tailored to the individual patient produces satisfying results referring to clinical outcome. Posterior approaches remain a viable alternative for a large proportion of patients with symptomatic thoracic disc herniations.

J Neurosurg 115:802–810, 2011.DOI: 10.3171/2011.5.JNS101812

Various surgical approaches, such as uni- and bifrontal, frontolateral, and pterional approaches, havebeen advocated for tuberculum sellae meningiomas. The authors retrospectively reviewed the effectiveness of a bilateralsubfrontal approach for tuberculum sellae meningiomas with special attention to ophthalmological outcomesand complications.

Methods. Between 1993 and 2009, 34 patients underwent surgery for removal of tuberculum sellae meningiomasat Osaka City University. Tumor size ranged from 14 to 45 mm. Thirty-two of 34 patients presented with visualdisturbances before the surgery. The visual functions in all patients were assessed using a visual impairment score(VIS) before and after surgery. Postoperative visual examination was performed 2 weeks after surgery. Long-termfollow-up examinations were conducted 1 year after surgery.

Results. Radical resection (Simpson Grades I and II) was accomplished in 27 patients, and subtotal or partialresection (Simpson Grades III and IV) was achieved in 7. There was no deterioration in postoperative visual outcome.Twenty-nine (90.6%) of 32 patients showed improved VIS compared with preoperative VIS. The average VIS was38.1 preoperatively, 23.5 in the short-term postoperative period, and 21.8 in the long-term postoperative period. Inthe short-term postoperative period, the visual function in 6 patients normalized, and visual problems persisted in theremaining 26. Six (23%) of 26 patients showed further improvement in VIS during the long-term follow-up period,and no patient exhibited a worsened VIS during this time. One patient complained of hyposmia after surgery, butthere was no indication of related complications such as CSF leakage or frontal brain contusion.

Conclusions. The bilateral subfrontal approach was previously avoided because of the relatively high rate ofcomplications in earlier surgical series of tuberculum sellae meningiomas. However, after developments in microsurgicaltechniques in recent years, the bilateral subfrontal approach can now provide satisfactory visual outcomes withminimal postoperative complications. Careful preservation of the blood supply to optic apparatus and early unroofingof the optic canal using a bilateral subfrontal approach led to further improvement in long-term postoperative visual outcome.

Neurosurgery 69:852–863, 2011 DOI: 10.1227/NEU.0b013e318225ea6b

The beneficial role of the extent of resection (EOR) in glioma surgery in correlation to increased survival remains controversial. However, common literature favors maximum EOR with preservation of neurological function, which is shown to be associated with a significantly improved outcome.

OBJECTIVE: In order to obtain a maximum EOR, it was examined whether high-field intraoperative magnetic resonance imaging (iMRI) combined with multimodal navigation contributes to a significantly improved EOR in glioma surgery.

METHODS: Two hundred ninety-three glioma patients underwent craniotomy and tumor resection with the aid of intraoperative 1.5 T MRI and integrated multimodal navigation. In cases of remnant tumor, an update of navigation was performed with intraoperative images. Tumor volume was quantified pre- and intraoperatively by segmentation of T2 abnormality in low-grade and contrast enhancement in high-grade gliomas.

RESULTS: In 25.9% of all cases examined, additional tumor mass was removed as a result of iMRI. This led to complete tumor resection in 20 cases, increasing the rate of grosstotal removal from 31.7% to 38.6%. In 56 patients, additional but incomplete resection was performed because of the close location to eloquent brain areas. Volumetric analysis showed a significantly (P , .01) reduced mean percentage of tumor volume following additional further resection after iMRI from 33.5% 6 25.1% to 14.7% 6 23.3% (World Health Organization [WHO] grade I, 32.8% 6 21.9% to 6.1% 6 18.8%; WHO grade II, 24.4% 6 25.1% to 10.8% 6 11.0%; WHO grade III, 35.1% 6 27.3% to 24.8% 6 26.3%; WHO grade IV, 34.2% 6 23.7% to 1.2% 6 16.2%).

CONCLUSION: MRI in conjunction with multimodal navigation and an intraoperative updating procedure enlarges tumor-volume reduction in glioma surgery significantly without higher postoperative morbidity.

Acta Neurochir (2011) 153:1907–1917. DOI 10.1007/s00701-011-1125-z

Diffuse WHO grade II glioma (GIIG) involving the occipital lobe is a rare entity. Its surgical resection remains controversial as it implies inducing a permanent visual deficit. For the first time to our knowledge, we report a consecutive surgical series of patients who underwent an occipital lobectomy for an LGG invading visual structures.

Method Six right-handed patients harboring a GIIG revealed by seizures (normal examination except a quadrantanopsia in one case) and located within the occipital lobe (4 left and 2 right tumors) were submitted to surgery. Before making this decision, the benefit-to-risk ratio of the resection was extensively discussed with the patient and his/her family, especially concerning the price to pay to remove the tumor, that is, to voluntarily generate a permanent hemianopsia. All the procedures were performed under awake condition using intraoperative electrostimulation, in order to pursue the resection until sensory-motor and/or language structures were encountered.

Findings An extensive occipital lobectomy was achieved in the six patients, with identification and preservation of sensory-motor pathways in the two cases with a right tumor and detection of language pathways in the four cases with a left tumor. The mean extent of resection was 93% (range: 91–100%). All patients experienced an expected postoperative deficit of the visual field (homonymous hemianopsia). Nonetheless, the six patients resumed a normal social and professional life (KPS at 90 in the 6 cases) with a mean follow-up of 58 months (range: 3–147 months)—with adjuvant treatment in three cases (in addition to a reoperation in two of them).

Conclusions Our findings suggest that, despite a definitive hemianopsia, an extensive surgical resection can be considered in the rare cases of occipital GIIG involving the primary visual structures, with patients able to maintain a normal life—except regarding the medico-legal problem of driving.

Neurosurg Rev DOI 10.1007/s10143-011-0334-5

Previous studies of chordoma have focused on either surgery, radiotherapy, or particular tumor locations. This paper reviewed the outcomes of surgery and proton radiotherapy with various tumor locations.

Between 2001 and 2008, 40 patients with chordomas of the skull base and cervical spine had surgery at our hospital. Most patients received proton therapy. Their clinical course was reviewed. Age, sex, tumor location, timing of surgery, extent of resection, and chondroid appearance were evaluated in regard to the progression-free survival (PFS) and overall survival (OS). The primary surgery (PS) group was analyzed independently. The extensive resection rate was 42.5%. Permanent neurological morbidity was seen in 3.8%. Radiotherapy was performed in 75% and the mean dose was 68.9 cobalt gray equivalents. The median followup was 56.5 months. The 5-year PFS and OS rates were 70% and 83.4%, respectively. Metastasis was seen in 12.5%. The tumor location at the cranio-cervical junction (CCJ) was associated with a lower PFS (P=0.007). In the PS group, a younger age and the CCJ location were related to a lower PFS (P=0.008 and P<0.001, respectively). The CCJ location was also related to a lower OS (P=0.043) and it was more common in young patients (P=0.002). Among the survivors, the median of the last Karnofsky Performance Scale score was 80 with 25.7% of patients experiencing an increase and 11.4% experiencing a decrease.

Multimodal surgery and proton therapy thus improved the chordoma treatment. The CCJ location and a younger age are risks for disease progression.

Neurosurgery 69:630–643, 2011 DOI: 10.1227/NEU.0b013e31821a872d

Controversy persists regarding the optimal treatment of pediatric craniopharyngiomas.

OBJECTIVE: We performed a meta-analysis of reported series of transcranial (TC) and transsphenoidal (TS) surgery for pediatric craniopharyngiomas to determine whether comparisons between the outcomes in TS and TC approaches are valid.

METHODS: Online databases were searched for English-language articles reporting quantifiable outcome data published between 1990 and 2010 pertaining to the surgical treatment of pediatric craniopharyngiomas. Forty-eight studies describing 2955 patients having TC surgery and 13 studies describing 373 patients having TS surgery met inclusion criteria.

RESULTS: Before surgery, patients who had TC surgery had less visual loss, more frequent hydrocephalus and increased intracranial pressure, larger tumors, and more suprasellar disease. After surgery, patients in the TC group had lower rates of gross total resection (GTR), more frequent recurrence after GTR, higher neurological morbidity, more frequent diabetes insipidus, less improvement, and greater deterioration in vision. There was no difference in operative mortality, obesity/hyperphagia, or overall survival percentages.

CONCLUSION: Directly comparing outcomes after TC and TS surgery for pediatric craniopharyngiomas does not appear to be valid. Baseline differences in patients who underwent each approach create selection bias that may explain the improved rates of disease control and lower morbidity of TS resection. Although TS approaches are becoming increasingly used for smaller tumors and those primarily intrasellar, tumors more amenable to TC surgery include large tumors with significant lateral extension, those that engulf vascular structures, and those with significant peripheral calcification.

J Neurosurg 115:647–658, 2011.DOI: 10.3171/2010.11.JNS102148

The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a givensized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions.

Methods. Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome.

Results. All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months. The mean relative increase in PFV accounted for 10% (range 1.5%–19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = -0.52, p = 0.09) and the basiocciput was short (r = -0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%.

Conclusions. The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.

Acta Neurochir. DOI 10.1007/s00701-011-1139-6

In recent years the endovascular treatment of intracranial aneurysms (coiling) has progressively gained recognition, particularly after the publication of the International Subarachnoid Aneurysm Trial (ISAT) in 2002. Despite the fact that in ISAT middle cerebral artery (MCA) aneurysms were clearly underrepresented, the study is often used as an argument to favor coiling above surgery in MCA aneurysms. Taken into account that MCA aneurysms are very well accessible for surgery, a contemporary assessment of the benefits of a preferred surgical strategy for MCA aneurysms was performed in a tertiary neurovascular referral center.

Methods A prospectively kept single-center database of 151 consecutive patients with an MCA aneurysm was reviewed over a 6-year period (2001–2006). Long-term follow-up after surgical treatment of a ruptured MCA aneurysm was obtained in 74 out of 77 (96%) patients. The outcome was compared with relevant series in the literature.

Results After a mean follow-up of 4.7 years, 59 out of 74 surgically treated patients (80%) with a ruptured MCA aneurysm had a good outcome (mRankin 0–2). All patients with an unruptured MCA aneurysm also had a good outcome after clipping. This is well-matched with the findings of the literature search, and competitive with the endovascular results.

Conclusion Surgical clipping is recommended as the principal treatment strategy for MCA aneurysms. This is not only ethically defendable in view of the surgical results but also in line with a strategy to maintain surgical experience within centralized neurovascular centers.

J Neurosurg 115:491–498, 2011. DOI: 10.3171/2011.4.JNS101922

Convexity meningiomas are expected to have a low recurrence rate given their classically “easy resectability.” Nonetheless, recurrence can occur. Factors playing a role in their recurrence are analyzed here, including the extent of resection and tumor histological type, among others, with a special emphasis on the cleavage plane.

Methods. The authors reviewed 100 cases of convexity meningiomas surgically treated between 1987 and 2001 with a median follow-up of 86 months (range 2–16 years). Preoperative and postoperative functional status, Simpson resection grade, histological type, and intraoperative surgical plane with pial vessel invasion were studied and cor- related with the recurrence rate.

Results. The average tumor size was 3.6 ± 0.4 cm. The pre- and postoperative Karnofsky Performance Scale scores were 92.6 ± 4.6 and 97.9 ± 2.2, respectively. Ninety-five lesions were benign (WHO Grade I) and 5 were atypical (WHO Grade II). Ninety-one and 9 tumors were subjected to Simpson Grade 1 and 3 resections (three Grade 3a and six Grade 3b), respectively. Surgical deaths did not occur. After a mean follow-up of 7.2 years, 4 meningiomas recurred; 2 (2.2%) after Simpson Grade 1 resections and 2 after Simpson Grade 3 (3a and 3b) resections (22.2%; p = 0.0034). When just the subgroup of Simpson Grade 1/WHO Grade I was studied, the recurrence rate decreased to 1.2% (1 of 86 cases). The recurrence of WHO Grade I tumors was higher in the subpial group than in the extrapial group (p = 0.025). No difference in recurrence according to the cleavage plane was seen in the WHO Grade II sub- group (p = 0.361). As for the subpial group, no difference in recurrence was noted between the WHO Grade I and II subgroups (p = 0.608). Importantly, however, the extrapial subgroup of WHO Grade II lesions had a higher recurrence rate compared with its counterpart in the WHO Grade I subgroup (p = 0.005).

Conclusions. Pial and vascular invasion affect the recurrence rate in convexity meningioma surgery. The recurrence rate of WHO Grade I tumors was higher among those with a subpial plane of dissection than among those with an extrapial one. Histological type did not determine the degree of pial invasion in WHO Grade I and II lesions.

Neurosurg Rev. DOI 10.1007/s10143-011-0340-7

The paper describes a retrospective study of a consecutive series of 20 midline anterior cranial fossa meningiomas (five of the olfactory groove, 14 of the tuberculum sellae, and one clinoidal), which were operated on via a supraorbital keyhole approach between 2002 and 2008.

The series includes three males and 17 females (mean age 57 years, mean size of the tumors 3.5×3 cm, and mean follow-up 48 months). Gross total excision was achieved in 18 cases and subtotal resection in two. Out of 14 patients with visual deficits, nine patients improved, one remained stable, and three deteriorated. Two patients presented a recurrence 3 years after surgery. One peri-operative death was recorded.

The subgroup of patients with tuberculum sellae meningiomas was analyzed in details. A meta-analysis of the major series of such meningiomas in the last 20 years has been performed in order to compare results of different surgical techniques. With regard to primary outcomes of these tumors, gross total removal, restoration of visual function, morbidity, mortality, and recurrence rates, the supraorbital approach, for selected cases, seems to offer valuable results, comparable with those reported in conventional and endoscopic approaches and with very low surgical aggressiveness. However, statistical data available from the literature, particularly on visual function, are still too limited to draw definitive conclusions.

The best surgical option for the individual patient cannot yet be standardized and should be chosen on the basis of tumor anatomy, pre-operative clinical symptoms, and surgeon’s experience.

Neuro-Oncology 13(9):943–949, 2011. doi:10.1093/neuonc/nor074

There is a lack of studies reporting on outcomes of control and treatment toxicities for neurocytomas.

A 25-year retrospective review of a tertiary center’s experience with neurocytomas was completed to report on these outcomes. All cerebral neurocytoma cases (19 patients; median age, 31 years; range, 18–62 years; 18 intraventricular and 1 extraventricular) treated between 1984 and 2009 were analyzed, including central pathology and radiology reviews.

Median follow-up was 104.5 months (range, 0.75–261.7 months). Primary treatment was surgery alone (n = 18 patients), followed by surgery and adjuvant radiotherapy (n = 1). The crude local control rate after surgery was 68% for all cases (cerebral neurocytomas) and 74% for central neurocytomas. Salvage therapies included further surgery (n = 4), radiation (n = 3), and chemotherapy (n = 1). Ten-year Kaplan-Meier overall and relapse-free survival rates were 82% and 62% and 81% and 57%, respectively, for all cases and for central neurocytomas only. The median overall survival and relapse-free survival were 104.5 and 79.3 months, respectively, for all cases and for central neurocytomas. Ten patients had grade 3/4 toxicity, and 1 patient had a grade 5 perioperative hemorrhage that resulted in death 23 days after surgery. Late grade 3/4 toxicities occurred in 9 patients. Three patients had permanent grade 2 motor or cognitive deficits.

We provide the first report outlining toxicities and survival outcomes in a series of 19 patients. Our experience suggests that initial surgery provides durable local control rates in two-thirds of patients, with low risk for significant permanent deficits. Salvage therapy with surgery and/or radiation provides durable local control in tumors that recur after surgery.