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Overdrainage shunt complications in idiopathic normal-pressure hydrocephalus and lumbar puncture opening pressure

Shunt complications of overdrainage

J Neurosurg 119:1498–1502, 2013

Management of idiopathic normal-pressure hydrocephalus (iNPH) is hard because the diagnosis is difficult and shunt surgery has high complication rates. An important complication is overdrainage, which often can be treated with adjustable–shunt valve manipulations but also may result in the need for subdural hematoma evacuation. The authors evaluated shunt surgery overdrainage complications in iNPH and their relationship to lumbar puncture opening pressure (LPOP).

Methods. The authors reviewed the charts of 164 consecutive patients with iNPH who underwent shunt surgery at their institution from 2005 to 2011. They noted age, sex, presenting symptoms, symptom duration, hypertension, body mass index (BMI), imaging findings of atrophy, white matter changes, entrapped sulci, LPOP, valve opening pressure (VOP) setting, number of valve adjustments, serious overdrainage (subdural hematoma requiring surgery), radiological overdrainage (subdural hematomas or hygroma seen on postoperative imaging), clinical overdrainage (sustained or postural headache), other complications, and improvements in gait, urine control, and memory.

Results. Eight patients (5%) developed subdural hematomas requiring surgery. All had an LPOP of greater than 160 mm H2O and an LPOP-VOP of greater than 40 mm H2O. Radiological overdrainage was more common in those with an LPOP of greater than 160 mm H2O than in those with an LPOP of less than 160 mm H2O (38% vs 21%, respectively; p = 0.024). The BMI was also significantly higher in those with an LPOP of greater than 160 mm H2O (median 30.2 vs 27.0, respectively; p = 0.005).

Conclusions. Serious overdrainage that caused subdural hematomas and also required surgery after shunting was related to LPOP and LPOP-VOP, which in turn were related to BMI. If this can be replicated, individuals with a high LPOP should have their VOP set close to the LPOP, or even higher. In doing this, perhaps overdrainage complications can be reduced.

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The silent phase of diffuse low-grade gliomas. Is it when we missed the action?

Diffuse low-grade glioma

Acta Neurochir (2013) 155:2237–2242

It is commonly believed that, before being diagnosed after onset of symptoms, diffuse low-grade glioma evolve silently for a long time. The present study aimed to estimate for the first time the exact duration of this silent phase, during which the glioma is radiologically visible but undiscovered.

Methods We retrospectively reviewed our French national database of diffuse low-grade glioma, searching for patients with an MRI-based assessment of their velocity of diameter growth at diagnosis and before any treatment (at least three MRIs over more than 6months). For each patient, the duration of the silent phase was estimated by the formula: duration = initial diameter / initial velocity of growth.

Results A total of 148 patients were included in the study. The mean lead-time duration (i.e., duration of the silent phase) was 14.0±7.8 years (median, 11.6 ; range, 1.6-39.4). The leadtime is statistically not correlated to the tumor volume. It is markedly decreasing with the velocity of diameter expansion.

Conclusions Diffuse low-grade glioma are radiologically detectable but clinically silent for more than a decade. Such a long period of silent evolution could explain our current failure to cure these tumors. It can also be viewed as a window of opportunity to detect these tumors earlier, suggesting the need to set up a screening program.

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Treatment of acromegaly by endoscopic transsphenoidal surgery

Treatment of acromegaly by endoscopic transsphenoidal surgery

J Neurosurg 119:1467–1477, 2013

Acromegaly is a disease that has significant morbidity and mortality related to high levels of growth hormone (GH) and insulin-like growth factor–I (IGF-I), and is usually caused by pituitary adenomas. The goal in this study was to investigate the role of endoscopic transsphenoidal surgery and surgical experience in the treatment of GH adenoma cases in relation to surgical results and hormonal cure rates, and to perform a review of the literature.

Methods. The authors present a retrospective analysis of 214 GH adenoma cases. Restoration of IGF-I levels to normal for age and sex, suppression of GH levels below 0.4 μg/L on the oral glucose tolerance test, and demonstration of the total removal of the tumor on MRI studies obtained after administration of contrast material at the 3-month postoperative follow-up visit were the criteria for cure.

Results. In total 214 patients with a mean age of 41.9 ± 12 years (range 17–75 years) and a male/female ratio of 106/108 were enrolled in the study. Cure was achieved in 134 (62.6%) of 214 patients. One hundred sixty-nine patients were primary cases, and of these 109 (64.5%) were cured, whereas 61 patients were previously operated cases and of these 25 (41%) were cured. With a 51.1% decrease in the 1st month postoperatively, IGF-I levels were found to be predictive of cure (74.4% sensitivity and 73.7% specificity). Cut-off values for GH levels in predicting cure for the 1st day, 1st week, and 1st month postoperatively were 2.33, 2.05, and 2.25 μg/L, respectively. The cut-off value for surgical experience was 57 for primary surgeries (58.5% cure rate before this cut-off value compared with 72.6% after it; p = 0.025) and 108 for all operations (45.8% vs 79.4%, p = 0.037). Although 28 patients were found to be in remission according to the criteria in 2000, they were not in remission according to the new consensus criteria. Nine of these cases (32.1%) had random GH levels < 1 μg/L at the 1-year follow-up. The 1-year IGF-I and GH levels in these 28 patients showed no significant difference when compared with the cases defined as cured according to the current criteria.

Conclusions. In acromegaly treatment, transsphenoidal endoscopic surgery performed by an expert senior surgeon and increased surgical experience are important for higher cure rates. Random GH levels < 2.33 μg/L after the 1st day postoperatively and a > 50% decrease in IGF-I levels after the 1st month postoperatively are predictive of cure. Moreover, there is no urgency for additional therapy in patients with GH levels of 0.4–1 μg/L and MRI sequences showing no tumor at the 3-month follow-up, because for these cases remission can be achieved at the 1-year follow-up.

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Surgical strategy in grade II astrocytoma

Surgical strategy in grade II astrocytoma

Acta Neurochir (2013) 155:2227–2235

We recently demonstrated a survival benefit of early resection in unselected diffuse low-grade gliomas (LGG). However, heterogeneity within the LGG entity warrants investigation in a homogenous subgroup. Astrocytoma represents the largest subgroup of LGG, and is characterized by diffuse growth and inferior prognosis. We aimed to study the effects of early resection compared to biopsy and watchful waiting in this subgroup.

Methods Patient data was retrospectively reviewed in two neurosurgical departments with regional referral practice. In one hospital, initial diagnostic biopsies and watchful waiting was favored, while early resections guided with three-dimensional (3D) ultrasound were advocated in the other hospital. This created a natural experiment with patient management heavy influenced by residential address. In the hospitals’ histopathology databases, all adult patients diagnosed with supratentorial LGG from 1998 through 2009 were screened (n =169) and underwent blinded histopathological review. Histopathological review concluded with 117 patients with grade II astrocytomas that were included in the present study. The primary end-point was overall survival assessed by a regional comparison.

Results Early resections were performed in 51 (82 %) versus 12 (22 %) patients in the respective hospitals (p <0.001). The two patient populations were otherwise similar. Median survival was 9.7 years (95 % CI 7.5–11.9) if treated in the hospital favoring early resections compared to 5.6 years (95 % CI 3.5– 7.6) if treated at the hospital favoring biopsy and watchful waiting (p =0.047). No difference in surgical-related neurological morbidity was seen (p =0.843).

Conclusions Early 3D ultrasound guided resections improve survival, apparently without increasedmorbidity, compared to biopsy and watchful waiting in patients with diffuse World Health Organization (WHO) grade II astrocytomas.

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Assessment of intracranial dynamics in hydrocephalus: effects of viscoelasticity on the outcome of infusion tests

Assessment of intracranial dynamics in hydrocephalus- effects of viscoelasticity on the outcome of infusion tests

J Neurosurg 119:1511–1519, 2013

The treatment of hydrocephalus requires insight into the intracranial dynamics in the patient. Resistance to CSF outflow (R0) is a clinically obtainable parameter of intracranial fluid dynamics that quantifies the apparent resistance to CSF absorption. It is used as a criterion for the selection of shunt candidates and serves as an indicator of shunt performance. The R0 is obtained clinically by performing 1 of 3 infusion tests: constant flow, constant pressure, or bolus infusion. Among these, the bolus infusion method has the shortest examination times and provides the shortest time of exposure of patients to artificially increased intracranial pressure (ICP) levels. However, for unknown reasons, the bolus infusion method systematically underestimates the R0. Here, the authors have tested and verified the hypothesis that this underestimation is due to lack of accounting for viscoelasticity of the craniospinal space in the calculation of the R0.

Methods. The authors developed a phantom model of the human craniospinal space in order to reproduce in vivo pressure-volume (PV) relationships during infusion testing. The phantom model followed the Marmarou exponential PV equation and also included a viscoelastic response to volume changes. Parameters of intracranial fluid dynamics, such as the R0, could be controlled and set independently. In addition to the phantom model, the authors designed a computational framework for virtual infusion testing in which viscoelasticity can be turned on or off in a controlled manner. Constant flow, constant pressure, and bolus infusion tests were performed on the phantom model, as well as on the virtual computational platform, using standard clinical protocols. Values for the R0 were derived from each infusion test by using both a standard method based on the Marmarou PV equation and a novel method based on a system identification approach that takes into account viscoelastic behavior.

Results. Experiments with the phantom model confirmed clinical observations that both the constant flow and constant pressure infusion tests, but not the bolus infusion test, yield correct R0 values when they are determined with the standard method according to Marmarou. Equivalent results were obtained using the computational framework. When the novel system identification approach was used to determine the R0, all of the 3 infusion tests yielded correct values for the R0.

Conclusions. The authors’ investigations demonstrate that intracranial dynamics have a substantial viscoelastic component. When this viscoelastic component is taken into account in calculations, the R0, is no longer underestimated in the bolus infusion test.

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Surgical Treatment of 127 Anterior Choroidal Artery Aneurysms

Anterior Choroidal Artery Aneurysms

Neurosurgery 73:933–940, 2013

The anterior choroidal artery (AChA) supplies important areas of the nervous system, particularly the posterior limb of the internal capsule and optic radiation. Treatment of AChA aneurysms poses particular challenges because of the complex anatomy of the aneurysm associated with the relatively small diameter of AChAs, making preservation of the parent vessel during clip ligation or endosaccular coiling challenging.

OBJECTIVE: To investigate the incidence and features of ischemia in treatment of AChA aneurysms.

METHODS: A prospectively maintained database of patients who underwent treatment of aneurysms from 1985 to 2011 was queried to find patients with AChA aneurysms. Age, sex, Hunt and Hess grade, treatment modality, and complications were analyzed by use of the unpaired Student t test and Fisher exact test.

RESULTS: One hundred twenty-two patients harbored 127 AChA aneurysms, and 67% (82 of 122) had multiple aneurysms. Treatment included 112 microsurgical clip ligations, 8 endosaccular coil embolizations, 5 aneurysmal wrappings, and 2 surgical explorations. Complications developed in 53% (67 of 127) of AChA aneurysms. Postoperative ischemia occurred in 12% (15 of 127) of treated aneurysms. The number of temporary clip applications was most closely associated with postoperative ischemia. Glasgow Outcome Scale scores of 4 or 5 were obtained by 78% at discharge, 89% at 6 months, and 85% at 1 year.

CONCLUSION: The ischemic complication rate from surgical treatment of AChA aneurysms is most closely associated with higher frequency of temporary clip applications for proximal control and may be lower than previously reported. Supplementary intraoperative tools and limitation of vessel manipulation should be used to improve outcomes.

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Decompressive craniectomy for severe traumatic brain injury: is life worth living?

decompressive craniectomy

J Neurosurg 119:1566–1575, 2013

The object of this study was to assess the long-term outcome and quality of life of patients who have survived with severe disability following decompressive craniectomy for severe traumatic brain injury (TBI).

Methods. The authors assessed outcome beyond 3 years among a cohort of 39 patients who had been adjudged either severely disabled or in vegetative state 18 months after decompressive craniectomy for TBI. Assessments performed included the Extended Glasgow Outcome Scale, modified Barthel Index (mBI), Zarit Burden Interview, and 36-Item Short-Form Health Survey (SF-36). The issue of retrospective consent for surgery was also assessed.

Results. Of the 39 eligible patients, 7 died, 12 were lost to follow-up, and 20 patients or their next of kin consented to participate in the study. Among those 20 patients, 5 in a vegetative state at 18 months remained so beyond 3 years, and the other 15 patients remained severely disabled after a median follow-up of 5 years. The patients’ average daily activity per the mBI (Pearson correlation coefficient [r] = -0.661, p = 0.01) and SF-36 physical score (r = -0.543, p = 0.037) were inversely correlated with the severity of TBI. However, the SF-36 mental scores of the patients were reasonably high (median 46, interquartile range 37–52). The majority of patients and their next of kin believed that they would have provided consent for surgical decompression even if they had known the eventual outcome.

Conclusions. Substantial physical recovery beyond 18 months after decompressive craniectomy for severe TBI was not observed; however, many patients appeared to have recalibrated their expectations regarding what they believed to be an acceptable quality of life.

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The Recesses of the Sellar Wall of the Sphenoid Sinus and Their Intracranial Relationships

The_Recesses_of_the_Sellar_Wall_of_the_Sphenoid

Neurosurgery 73[ONS Suppl 2]:ons117–ons131, 2013

The sellar wall of the sphenoid sinus and its recesses have been previously studied, but their intracranial relationships to the diaphragma sellae, tuberculum, clinoid segment of the internal carotid artery, chiasmatic sulcus, and middle clinoid process need further definition.

OBJECTIVE: To describe these intra- and extracranial relationships of the recesses in the anterior sellar wall.

METHODS: The middle clinoid was studied in 132 parasellar areas of dry crania. Thirtyeight parasellar areas of formalin-fixed/silicone-colored specimens were dissected. After transsphenoidal endoscopic exposure, the optic, carotid, and sellar prominences; lateral opticocarotid and tuberculum recesses; and caroticosellar and medial opticocarotid points were identified. High-speed drills opened 1-mm perforations at these points to allow study of intracranial relationships.

RESULTS: Two recesses and 2 junction points can be recognized in the sphenoid sinus: lateral opticocarotid and tuberculum recesses and medial opticocarotid and caroticosellar points. The lateral opticocarotid recess corresponds to the optic strut base, and the clinoid segment of the internal carotid artery is located medially. The diaphragma sellae attachment is at the level of the tuberculum recess, which in 50% of cases corresponds to the tuberculum. A middle clinoid in base or height greater than 1.5 mm is present in 21.1% and a caroticoclinoid ring in 3%. The middle clinoid is 1 mm inferior and lateral to the caroticosellar point and 4.7 mm inferior to the medial opticocarotid point.

CONCLUSION: An understanding of the intra- and extracranial relationships of the recesses of the sphenoid sinus will aid in accurately directing transsphenoidal approaches.

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Very Late Complications of Cervical Arthroplasty

Very Late Complications of Cervical Arthroplasty

Spine 2013;38:2223––2226

Prospective, single-site, randomized, Food and Drug Administration––approved investigational device exemption clinical trials of 2 cervical arthroplasty (CA) devices.

Objective. To evaluate complications with CA occurring more than 4 years after the surgical procedure in Food and Drug Administration clinical trials of the Bryan and Prestige LP arthroplasty devices. Summary of Background Data. Reports of several randomized clinical studies have shown CA to be a safe and effective alternative to anterior cervical fusion in the treatment of degenerative cervical disc disorders. A majority include follow-up intervals of 4 years or less.

Methods. Between 2002 and 2006, 94 patients were enrolled in Food and Drug Administration studies of the Bryan and Prestige LP cervical disc devices. Charts, imaging studies, and hospital records were reviewed for those who underwent arthroplasty and returned more than 4 years after their surgical procedure with neck-related pain or dysfunction. Results. Excluding adjacent segment disease that occurred with a similar rate for patients who underwent fusion and arthroplasty, 5 patients, all treated with arthroplasty, returned for evaluation of neck and arm symptoms between 48 and 72 months after surgery. Four patients had peridevice vertebral body bone loss. One patient had posterior device migration and presented with myelopathy. Three required revision surgery and 2 were observed. Four patients maintained follow-up and reported stabilization or improvement in symptoms.

Conclusion. Despite their similarities, CA and fusion are not equivalent procedures in this study in regard to very late complications. Similar to large joint arthroplasty, delayed devicerelated complications may occur with CA. These complications commenced well beyond the time frame for complications associated with more traditional cervical spine procedures. Both patients and surgeons should be aware of the potential for very late device-related complications occurring with CA and the need for revision surgery.

Level of Evidence: 1

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Keyhole Supracerebellar Transtentorial Transcollateral Sulcus Approach to the Lateral Ventricle

Keyhole Supracerebellar Transtentorial Transcollateral Sulcus Approach to the Lateral Ventricle

Neurosurgery 73[ONS Suppl 2]:onsE295–onsE301, 2013

Meningiomas of the lateral ventricles are commonly located in the atria. Surgical access to such tumors is challenging because of their deep location and proximity to critical neurovascular structures, particularly if situated on the dominant side. Although a number of approaches have been described in the literature, most carry the risk of postoperative neuropsychological, visual, or speech deficits, especially when operating on the dominant hemisphere. The supracerebellar transtentorial transcollateral sulcus (STTCS) approach offers the potential to circumvent functionally important structures, reducing the risk of these approach-related neurological deficits.

CLINICAL PRESENTATION: Two patients with dominant hemisphere trigonal meningiomas underwent surgical resection with the use of the STTCS approach. Neuronavigation was used to carefully plan the incision, craniotomy, and exposure, and also intraoperatively to orientate the operating surgeon at key steps, particularly when raising the tentorial flap in line with the tumor. Endoscopy was used to provide increased light intensity, an extended viewing angle, and higher magnification in comparison with a microscope. Specially designed tube-shaft instruments were also used to assist with manipulation through the narrow surgical corridor. In both cases, the tumors were fully resected without approach-related morbidity.

CONCLUSION: The STTCS approach provides good access to tumors located in the trigonal region, reducing the risk of iatrogenic language or visual field deficits. In dominant hemisphere lesions, in the hands of an experienced neurosurgeon, the STTCS approach is an effective alternative to existing techniques.

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Management and outcome of high-grade multicentric gliomas

Management and outcome of high-grade multicentric gliomas

Acta Neurochir (2013) 155:2245–2251

Multicentric malignant gliomas are wellseparated tumours in different lobes or hemispheres, without anatomical continuity between lesions. The purpose of this study was to explore the clinical features, the pathology and the outcome according to the management strategies in a consecutive series of patients treated at a single institution. In addition, an analysis of the existing literature is presented.

Methods For the institutional analysis, a retrospective review of all patients who underwent treatment for multicentric gliomas in the last 7 years was performed. For the analysis of the literature, a MEDLINE search with no date limitations was accomplished for surgical treatment of multicentric malignant gliomas.

Results Two hundred and thirty-nine patients with glioma were treated in our department. Eighteen patients (7.5%) with a mean age of 64 years (age range, 37–78 years) presented multicentric malignant gliomas. Thirteen patients (72 %) underwent surgical resection of at least one lesion that was followed by adjuvant treatment in all but one case. Five patients (28 %) underwent stereotactic biopsy and thereafter received chemotherapy. A survival advantage was associated with resection of at least one lesion followed by adjuvant treatment (median overall survival 12 months) compared with 4 months for stereotactic biopsy followed by chemotherapy. Similar results were obtained from the review of the literature.

Conclusions Resection of at least one lesion seems to play a significant role in the management of selected patients with multicentric malignant gliomas. Multi-institutional studies on larger series are warranted to define how aggressively the patients with malignant multicentric gliomas should be treated.

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Role of intraoperative neurophysiological monitoring during fluorescence-guided resection surgery

Role of intraoperative neurophysiological monitoring during fluorescence-guided resection surgery

Acta Neurochir (2013) 155:2201–2213

Fluorescence-guided resection (FGR) using 5- aminolevulinic acid (5-ALA) exhibits a potential risk of permanent neurological deficits that can be minimized using intraoperative neurophysiological monitoring (IONM). We assessed the role of IONM in FGR surgery in patients harboring tumors in or near eloquent areas.

Methods IONM and FGR surgeries were performed on 34 patients (49.8±2.4 years) harbored malignant primary gliomas near eloquent cortical areas or semioval center. Different combinations of neurophysiological techniques were used depending on each patient.

Results Gross total resection (GTR) was achieved in 66.7 % of the patients, mean 90.4±3.7 % without neurological deficits. Resection in four patients was stopped by the occurrence of severe warning criteria despite the presence of fluorescence. Hemispheric transcranial electrical stimulation was safe and confident even in cortical surgery. Notably, a significant percentage of patients exhibited clinical improvement after the surgery. One week after surgery, only one patient worsened, and seven patients improved. At 3 months, 27.8 % of the patients improved, and the other patients maintained a similar status to their pre-surgery condition.Warning common criteria (amplitude reduction and/or latency increase) appeared in 68.2 and 50.0 % of patients during cortical or semioval surgery, respectively, with neither a false-negative nor a false-positive clinical outcome. Although 5-ALA exhibits phototoxicity, VEP did not induce any secondary effects in the visual system, including eyelids.

Conclusions IONM can be helpful during surgery to maximize the tumor resection, meanwhile help to avoid neurological deficits and, therefore, to improve the quality of life of these patients.

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Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson Grade IV resection

Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson Grade IV resection

J Neurosurg 119:1373–1379, 2013

Meningiomas treated by subtotal or partial resection are associated with significantly shorter recurrencefree survival than those treated by gross-total resection. The Simpson grading system classifies incomplete resections into a single category, namely Simpson Grade IV, with wide variations in the volume and location of residual tumors, making it complicated to evaluate the achievement of surgical goals and predict the prognosis of these tumors. Authors of the present study investigated the factors related to necessity of retreatment and tried to identify any surgical nuances achievable with the aid of modern neurosurgical techniques for meningiomas treated using Simpson Grade IV resection.

Methods. This retrospective analysis included patients with WHO Grade I meningiomas treated using Simpson Grade IV resection as the initial therapy at the University of Tokyo Hospital between January 1995 and April 2010. Retreatment was defined as reresection or stereotactic radiosurgery due to postoperative tumor growth.

Results. A total of 38 patients were included in this study. Regrowth of residual tumor was observed in 22 patients with a mean follow-up period of 6.1 years. Retreatment was performed for 20 of these 22 tumors with regrowth. Risk factors related to significantly shorter retreatment-free survival were age younger than 50 years (p = 0.006), postresection tumor volume of 4 cm3 or more (p = 0.016), no dural detachment (p = 0.001), and skull base location (p = 0.016). Multivariate analysis revealed that no dural detachment (hazard ratio [HR] 6.42, 95% CI 1.41–45.0; p = 0.02) and skull base location (HR 11.6, 95% CI 2.18–218; p = 0.002) were independent risk factors for the necessity of early retreatment, whereas postresection tumor volume of 4 cm3 or more was not a statistically significant risk factor.

Conclusions. Compared with Simpson Grade I, II, and III resections, Simpson Grade IV resection includes highly heterogeneous tumors in terms of resection rate and location of the residual mass. Despite the difficulty in analyzing such diverse data, these results draw attention to the favorable effect of dural detachment (instead of maximizing the resection rate) on long-term tumor control. Surgical strategy with an emphasis on detaching the tumor from the affected dura might be another important option in resection of high-risk meningiomas not amenable to gross-total resection.

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Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery: Incidence and Outcomes

Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery- Incidence and Outcomes

Neurosurgery 73[ONS Suppl 2]:ons261–ons270, 2013

Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery is a feared complication that is not well studied or reported.

OBJECTIVE: To evaluate the incidence, to identify potential risk factors, and to present management strategies and outcomes of ICA injury during endonasal skull base surgery at our institution. METHODS: We performed a retrospective review of all endoscopic endonasal operations performed at our institution between 1998 and 2011 to examine potential factors predisposing to ICA injury. We also documented the perioperative management and outcomes after injury.

RESULTS: There were 7 ICA injuries encountered in 2015 endonasal skull base surgeries, giving an incidence of 0.3%. Most injuries (5 of 7) involved the left ICA, and the most common diagnosis was chondroid neoplasm (chordoma, chondrosarcoma; 3 of 7 [2% of 142 cases]). Two injuries occurred during 660 pituitary adenoma resections (0.3%). The paraclival ICA segment was the most commonly injured site (5 of 7), and transclival and transpterygoid approaches had a higher incidence of injury, although neither factor reached statistical significance. Four of 7 injured ICAs were sacrificed either intraoperatively or postoperatively. No patient suffered a stroke or neurological deficit. There were no intraoperative mortalities; 1 patient died postoperatively of cardiac ischemia. One of the 3 preserved ICAs developed a pseudoaneurysm over a mean follow-up period of 5 months that was treated endovascularly.

CONCLUSION: ICA injury during endonasal skull base surgery is an infrequent and manageable complication. Preservation of the vessel remains difficult. Chondroid tumors represent a higher risk and should be resected by surgical teams with significant experience.

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Three dimensional anatomy of the human nucleus accumbens

Three dimensional anatomy of the human nucleus accumbens

Acta Neurochir (2013) 155:2389–2398

The Nucleus accumbens (Acc) is the main structure of the ventral striatum. It acts as a motor-limbic interface, being involved in emotional and psychomotor functions, frequently disturbed in neuropsychiatric disorders such as obsessive compulsive disorder and addiction. Most of the studies concerning the Acc were made in animals and those performed in humans are contradictory. Nevertheless, it has become a target for stereotactic deep brain stimulation for some of those diseases, when refractory to medical treatment. Previous studies performed by our group have established the localization, limits and dimensions of the human Acc and its stereotactic coordinates. Now it is our purpose to perform the Acc anatomical three-dimensional (3D) reconstruction in order to clarify its shape and topography and to render this nucleus a safer target for stereotactic procedures.

Methods Anatomical coronal slicing of ten Acc from human brains was performed, perpendicular to the anterior commissure-posterior commissure line and to the midline; then the Acc contours were traced and its dimensions and 3D stereotactic coordinates measured, on each slice. Finally a 3D computerized model was created.

Results The human Acc was identified as a distinct brain structure, with clear-cut limits on its posterior half. It lies parallel to the midline, descends caudally, and progresses from a globose to a flattened and dorsolateral concave shape. Its main expression is subcomissural.

Conclusion This study defined more accurately the 3D anatomy of the human Acc, providing new tools for stereotactic procedures.

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Long-term Follow-up of Blister Aneurysms of the Internal Carotid Artery

Blister ICA aneurysm

Neurosurgery 73:1026–1033, 2013

Blister aneurysms of the internal carotid artery (ICA) are uncommon. There is a paucity of data on the long-term outcomes of patients.

OBJECTIVE: To review our experience with the treatment of these lesions.

METHODS: We retrospectively reviewed all aneurysms treated at our institution between 1994 and 2005. Relevant operative notes, radiology reports, and inpatient/ outpatient records were reviewed.

RESULTS: Seventeen patients (3 male, 14 female) with 18 blister aneurysms of the ICA were identified. The mean age was 44.6 years (range, 17-72; median, 42 years). Twelve patients (70.6%) presented with aneurysmal subarachnoid hemorrhage. The mean admission Glasgow Outcome Scale score was 4.3 (range, 2-5; median, 5). All patients were initially treated using microsurgical technique with direct clipping (n = 15; 83.3%) or clip-wrapping with Gore-Tex (n = 3, 16.7%). There were 4 cases of intraoperative rupture, all associated with attempted direct clipping; all 4 cases were successfully clipped. Two cases rebled post-treatment. Both rebleeding episodes were managed with endovascular stenting. Follow-up angiography was available for 14 patients and revealed a new aneurysm adjacent to the site of clipping in 1 patient and in-stent stenosis in 2. At the mean follow-up of 74.5 months (median, 73; range, 7-165), the mean Glasgow Outcome Scale score was 4.6 (range, 2-5; median, 5).

CONCLUSION: Microsurgical treatment of blister aneurysms of the ICA results in excellent outcome. In the evolution of treating these friable aneurysms, we have modified our clip-wrapping technique and use this technique when direct clipping is not feasible.

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Long-term follow-up of standard microdiscectomy versus minimal access surgery for lumbar disc herniations

Long-term follow-up of standard microdiscectomy versus minimal access surgery for lumbar disc herniations

Acta Neurochir (2013) 155:2333–2338

Surgery of lumbar disc herniations is one of the most common neurosurgical procedures. New surgical approaches and techniques are constantly evolving. We present our long-term follow-up results comparing standard open microdiscectomy (SOMD) andminimal access microdiscectomy (MAMD) for single-level lumbar disc herniations.

Methods Patients were randomized in two groups receiving eitherMAMDor SOMD. Physical and mental health and pain relief were assessed (ODI, SF-36 questionnaire, VAS leg and back pain). In addition, all patients received MR imaging for morphological evaluation of postoperative peridural scar tissue formation.

Results Of the 60 initial patients (SOMD: 30 pts, MAMD: 30 pts), 38 were available for long-term follow-up. Mean follow-up time was 33 months. Long-term follow-up revealed significant postoperative pain relief in both groups. Good to excellent results concerning physical and mental health and pain relief were achieved in both groups. Significantly less peridural scar tissue formation was observed in the MAMD patients, but without clinical impact.

Conclusion MAMD is a feasible alternative to the standard open approach. Both groups show significant and long-lasting pain relief and good to excellent results regarding healthrelated quality of life. Congruent to our short-term results, we observed slightly but not statistically significant better clinical results in the MAMD group when compared to the SOMD group.

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The Aqueduct of Sylvius: Applied 3-T Magnetic Resonance Imaging Anatomy and Morphometry With Neuroendoscopic Relevance

Aqueduct of Sylvius MRI morphometry

Neurosurgery 73[ONS Suppl 2]:ons132–ons140, 2013

The aqueduct of Sylvius (AqSylv) is a structure of increasing importance in neuroendoscopic procedures. However, there is currently no clear and adequate description of the normal anatomy of the AqSylv.

OBJECTIVE: To study in detail hitherto unavailable normal magnetic resonance imaging morphometry and anatomic variants of the AqSylv.

METHODS: We retrospectively studied normal midsagittal T1-weighted 3-T magnetic resonance images in 100 patients. We measured widths of the AqSylv pars anterior, ampulla, and pars posterior; its narrowest point; and its length. We recorded angulation of the AqSylv relative to the third ventricle as multiple deviations of the long axis of the AqSylv from the Talairach bicommissural line. We statistically determined age- and sexrelated changes in AqSylv morphometry using the Pearson correlation coefficient. We measured angulation of the AqSylv relative to the fourth ventricle and correlated this to the cervicomedullary angle (a surrogate for head position).

RESULTS: Patients were 13 to 83 years of age (45% male, 55% female). Mean morphometrics were as follows: pars anterior width, 1.1 mm; ampulla width, 1.2 mm; pars posterior width, 1.4 mm; length, 14.1 mm; narrowest point, 0.9 mm; and angulation in relation to the third and fourth ventricles, 26 and 18, respectively. Age correlated positively with width and negatively with length of the AqSylv. There was no correlation between AqSylv alignment relative to the foramen magnum and the cervicomedullary angle.

CONCLUSION: Normative dimensions of the AqSylv in vivo are at variance with published cadaveric morphometrics. The AqSylv widens and shortens with cerebral involution. Awareness of these normal morphometrics is highly useful when stent placement is an option during aqueductoplasty. Reported data are valuable in guiding neuroendoscopic management of hydrocephalus and aqueductal stenosis.

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Hypertensive slit ventricle syndrome: pseudotumor cerebri with a malfunctioning shunt?

slit ventricles

J Neurosurg 119:1503–1510, 2013

Symptomatic shunt malfunction without ventricular enlargement is known as slit ventricle syndrome (SVS). Patients presenting with this syndrome are not a homogeneous group. Of the 5 different types classified by Rekate, Type 1 is caused by CSF overdrainage and is associated with low pressures; Types 2 and 3 are associated with shunt blockage and elevated CSF pressures; Type 4 is cephalocranial disproportion that increases brain parenchymal pressure but not CSF pressure; and Type 5 is headache unrelated to shunt function. The low and normal CSF pressure types are relatively well understood, but the high-pressure forms are more problematic. In the high-pressure forms of SVS it is said that the lack of ventricular dilation is related to a reduction in brain compliance analogous to idiopathic intracranial hypertension or pseudotumor cerebri. Despite this, there is little evidence in the literature to support this conjecture.

With this in mind, 3 cases of SVS associated with elevated CSF pressure are presented. The MR venogram findings and hemodynamics of these 3 cases are shown to be identical to those of pseudotumor cerebri. A literature review indicates that an underlying venous impairment may be functioning in the patients who re-present with small ventricles following shunt malfunction.

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Bilateral stereotactic anterior capsulotomy for obsessive-compulsive disorder: long-term follow-up

DBS-OCD

J Neurol Neurosurg Psychiatry 2013;84:1208–1213

Psychosurgery, such as anterior capsulotomy, is a therapeutic option for treatment-resistant obsessive-compulsive disorder (OCD). In this paper, we present a prospective, long-term follow-up study aimed at evaluating both the efficacy and the safety of anterior capsulotomy for the treatment of severe, refractory OCD.

Methods Twenty-four patients were surgically treated in our centre between 1997 and 2009, 19 of whom were included in this study. Patients were assessed at 3, 6, 12, and 24 months and last follow-up (mean of 7 years) was carried out by phone. OCD symptom severity was evaluated using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). A patient with an improvement rate of over 35% in the Y-BOCS score was considered a responder, while a patient with a 25% improvement was considered a partial responder.

Results With a mean improvement of 31% in the Y-BOCS score at long-term follow-up, 36.8% of the patients responded fully to the procedure and 10.5% were considered partial responders, for an overall response rate of 47.3% of patients. At the end of the study, 3/19 patients had recovered (Y-BOCS score <8) and 3/19 were in remission (Y-BOCS score <16). No cases of mortality were reported and the overall adverse event rate was 57.9%. Only 2 patients had permanent surgical complications.

Conclusions Anterior capsulotomy is an effective and safe technique for the treatment of severe refractory OCD in patients who have no other alternative to improve their symptoms.

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