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Unilateral Extradural Motor Cortex Stimulation Is Safe and Improves Parkinson Disease at 1 Year

Neurosurgery 71:815–825, 2012

The primary motor cortex, which is part of the corticobasal ganglia loops, may be an alternative option for the surgical treatment of Parkinson disease.

OBJECTIVE: To report on the 1-year safety and efficacy of unilateral extradural motor cortex stimulation in Parkinson disease.

METHODS: A quadripolar electrode strip was extradurally implanted over the motor cortex. Stimulation was continuously delivered through the electrode paddle contralateral to the most affected clinical side. Subjects were prospectively evaluated by the Unified Parkinson’s Disease Rating Scale (UPDRS) and the Parkinson’s Disease Quality of Life Questionnaire. In addition, an extensive cognitive and behavioral assessment and electroencephalogram recording were performed.

RESULTS: Nine patients were included in this study. No surgical complications or adverse events occurred. Moreover, no cognitive or behavioral changes were observed. Under the off-medication condition, the UPDRS III at baseline was decreased by 14.1%, 23.3%, 19.9%, and 13.2%, at 1, 3, 6, and 12 months, respectively. The motor effects were bilateral, appeared after 3 to 4 weeks of stimulation, and outlasted the stimulation itself for 3 to 4 weeks in 1 case of stimulator accidental switching off. The UPDRS IV was decreased by 40.8%, 42.1%, and 35.5% at 1, 3, and 12 months, respectively. The scores on the Parkinson’s Disease Quality of Life Questionnaire were increased at months 3, 6, and 12.

CONCLUSION: Extradural motor cortex stimulation is a safe procedure. After 12 months, the patients demonstrated a moderate improvement of motor symptoms (particularly axial symptoms) and quality of life.

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Who Should Have Surgery for Spinal Stenosis?

Spine 2012 ; 37 : 1791 – 1802

Study Design. Combined prospective randomized controlled trial and observational cohort study of spinal stenosis (SpS) with an as-treated analysis.

Objective. To determine modifiers of the treatment effect (TE) of surgery (the difference between surgical and nonoperative outcomes) for SpS using subgroup analysis.

Summary of Background Data. The Spine Patient Outcomes Research Trial demonstrated a positive surgical TE for SpS at the group level. However, individual characteristics may affect TE. No previous studies have evaluated TE modifiers in SpS.

Methods. SpS patients were treated with either surgery (n = 419) or nonoperative care (n = 235) and were analyzed according to treatment received. Fifty-three baseline variables were used to define subgroups for calculating the time-weighted average TE for the Oswestry Disability Index (ODI) over 4 years (TE = ΔODI surgery – ΔODI nonoperative ). Variables with significant subgroup × treatment interactions ( P < 0.05) were simultaneously entered into a multivariate model to select independent TE predictors.

Results. Other than smokers, all analyzed subgroups including at least 50 patients improved signifi cantly more with surgery than with nonoperative treatment ( P < 0.05). Multivariate analysis demonstrated: baseline ODI ≤ 56 (TE –15.0 vs. –4.4, ODI > 56, P < 0.001), not smoking (TE –11.7 vs. –1.6 smokers, P < 0.001), neuroforaminal stenosis (TE –14.2 vs. –8.7 no neuroforaminal stenosis, P = 0.002), predominant leg pain (TE –11.5 vs. –7.3 predominant back pain, P = 0.035), not lifting at work (TE –12.5 vs . –0.5 lifting at work, P = 0.017), and the presence of a neurological deficit (TE –13.3 vs . –7.2 no neurological deficit, P < 0.001) were associated with greater TE.

Conclusion. With the exception of smokers, patients who met strict inclusion criteria improved more with surgery than with nonoperative treatment, regardless of other specific characteristics. However, TE varied significantly across certain subgroups, and these data can be used to individualize shared decision making discussions about likely outcomes. Smoking cessation should be considered before surgery for SpS.

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Microsurgical clipping of true posterior communicating artery aneurysms

Acta Neurochir (2012) 154:1707–1710

“True” posterior communicating artery (PCOM) aneurysms are rare variants in which the aneurysm arises solely from the PCOM rather than the junction of the internal carotid artery and the PCOM.

Methods It is critical to note that for true PCOM aneurysms, the neck arises distal to the origin of the PCOM and therefore lies in what is traditionally an intra-operative blind spot. The PCOM must be followed posteriorly to visualise the aneurysm neck for microsurgical clipping.

Conclusions A thorough pre-operative understanding of this unique anatomy is essential in minimising morbidity associated with microsurgical clipping of this aneurysm configuration.

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Intraoperative subcortical electrical mapping of optic radiations in awake surgery for glioma involving visual pathways

J Neurosurg 117:466–473, 2012

Preservation of the visual field in glioma surgery, especially avoidance of hemianopia, is crucial for patients’ quality of life, particularly for driving. Recent studies used tractography or cortical occipital stimulation to try to avoid visual deficit. However, optic radiations have not been directly mapped intraoperatively. The authors present, for the first time to their knowledge, a consecutive series of awake surgeries for cerebral glioma with intrasurgical identification and preservation of visual pathways using subcortical electrical mapping.

Methods. Fourteen patients underwent awake resection of a glioma (1 WHO Grade I, 11 WHO Grade II, 2 WHO Grade III) involving the optic radiations. The patients had no presurgical visual field deficit. Intraoperatively, a picture-naming task was used, with presentation of 2 objects situated diagonally on a screen divided into 4 quadrants. An image was presented in the quadrant to be saved and another image was presented in the opposite quadrant. Direct subcortical electrostimulation was repeatedly performed without the patient’s knowledge, until optic radiations were identified (transient visual disturbances). All patients underwent an objective visual field assessment 3 months after surgery.

Results. All patients experienced visual symptoms during stimulation. These disturbances led the authors to stop the tumor resection at that level. Postoperatively, only 1 patient had a permanent hemianopia, despite an expected quadrantanopia in 12 cases. The mean extent of resection was 93.6% (range 85%–100%).

Conclusions. Online identification of optic radiations by direct subcortical electrostimulation is a reliable and effective method to avoid permanent hemianopia in surgery for gliomas involving visual pathways.

 

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Endoscopic Endonasal Transclival Approach to the Jugular Tubercle

Neurosurgery 71[ONS Suppl 1]:ons146–ons159, 2012

The jugular tubercle is a rounded bony prominence that arises from the inferolateral margin of the clivus. In a previous publication, we described the surgical anatomy of the expanded endonasal approach to the jugular tubercle.

OBJECTIVE: To illustrate the translation of laboratory work to the operating room describing the anatomic and technical nuances of the endonasal approach to the jugular tubercle.

METHODS: We review the relevant surgical anatomy needed to perform an endonasal approach to the jugular tubercle, and we select 4 different lesions to illustrate the application of our laboratory findings.

RESULTS: In the first case, exposure and partial drilling of the jugular tubercle was critical to gain an adequate corridor to the meningioma, particularly to its inferolateral margin. This allowed for early devascularization, safe extracapsular dissection, and preservation of surrounding neurovascular structures. In addition, the jugular tubercle was hyperostotic and its resection, along with generous dural removal, provided a grade I Simpson tumor resection. In the second (chondrosarcoma) and third (chordoma) cases, the jugular tubercle was infiltrated by tumor, and consequently its complete resection was essential to achieve total tumor removal. In the last case, an unusual adrenocorticotropic hormone-secreting adenoma recurrence at the jugular tubercle region, the technical modification of the transclival approach presented here was successfully applied to achieve complete resection and Cushing disease remission.

CONCLUSION: The transjugular tubercle variant of the expanded endonasal transclival approach allows for direct access to ventrolateral lesions in the inferior clival/petroclival region with no cerebral or cerebellar retraction, or cranial nerve manipulation during the approach.

 

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Independent predictors for recurrence of chronic subdural hematoma

Acta Neurochir (2012) 154:1541–1548 DOI 10.1007/s00701-012-1399-9

Chronic subdural hematoma is characterized by blood in the subdural space that evokes an inflammatory reaction. Numerous factors potentially associated with recurrence of chronic subdural hematoma have been reported, but these factors have not been sufficiently investigated. In this study, we evaluated the independent risk factors of recurrence.

Methods We analyzed data for 420 patients with chronic subdural hematoma treated by the standard surgical procedure for hematoma evacuation at our institution.

Results Ninety-two (21.9 %) patients experienced at least one recurrence of chronic subdural hematoma during the study period. We did not identify any significant differences between chronic subdural hematoma recurrence and current antiplatelet therapy. The recurrence rate was 7 % for the homogeneous type, 21 % for the laminar type, 38 % for the separated type, and 0 % for the trabecular type. The rate of recurrence was significantly lower in the homogeneous and trabecular type than in the laminar and separated type. We performed a multivariate logistic regression analysis and found that postoperative midline shifting (OR, 3.6; 95 % CI, 1.618-7.885; p00.001), diabetes mellitus (OR, 2.2; 95 % CI, 1.196-3.856; p=0.010), history of seizure (OR, 2.6; 95 % CI, 1.210-5.430; p=0.014), width of hematoma (OR, 2.1; 95 % CI, 1.287-3.538; p=0.003), and anticoagulant therapy (OR, 2.7; 95 % CI, 1.424-6.960; p=0.005) were independent risk factors for the recurrence of chronic subdural hematoma.

Conclusions We have shown that postoperative midline shifting (≥5 mm), diabetes mellitus, preoperative seizure, preoperative width of hematoma (≥20 mm), and anticoagulant therapy were independent predictors of the recurrence of chronic subdural hematoma. According to internal architecture of hematoma, the rate of recurrence was significantly lower in the homogeneous and the trabecular type than the laminar and separated type.

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Visual Outcomes After Surgical Treatment of Adult Craniopharyngiomas

Neurosurgery 71:715–721, 2012 DOI: 10.1227/NEU.0b013e318262146b

Craniopharyngiomas (CRPs) often cause visual deterioration (VD) due to the close vicinity of the optic apparatus.

OBJECTIVE: To evaluate longitudinal visual outcomes after surgery of CRP and determine the prognostic factors thereof.

METHODS: One hundred forty-six adult patients who underwent surgery for newly diagnosed CRP were retrospectively reviewed. There were 87 male patients (60%), and the median age was 41 years (range, 18-75). The mean follow-up duration was 88.7 months (range, 24-307). A visual impairment score was used to assess the short-term (,1 month) and long-term (.2 years) visual outcomes.

RESULTS: Gross total removal was performed in 53 patients (36%), and tumor recurrence occurred in 40 patients (27%). The average preoperative, short- and longterm visual impairment scores were 44.4, 38.5, and 38.1, respectively, on a 0- to 100-point scale (with 100 indicating the worst vision). Short- and long-term VD occurred in 28 (19%) and 39 patients (27%), respectively. Subtotal removal (STR) alone (P = .010; OR = 4.8), short-termVD (P<.001; OR = 39.7), and tumor recurrence (P<.001; OR = 28.2) were significant risk factors for long-term VD in the multivariate analysis. Patients undergoing STR alone had higher tumor recurrence rates in comparison with those who underwent gross total removal or STR with adjuvant therapy (P < .001).

CONCLUSION: Short-term VD secondary to the surgical insult and the recurrence of the tumor were strong predictors of long-term visual outcomes after surgical treatment for CRP. STR alone may be an ineffective strategy for achieving tumor control and optimal visual outcomes in patients with CRP.

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Surgery for vestibular schwannomas: a systematic review of complications by approach

Neurosurg Focus 33 (3):E14, 2012

Various studies report outcomes of vestibular schwannoma (VS) surgery, but few studies have compared outcomes across the various approaches. The authors conducted a systematic review of the available data on VS surgery, comparing the different approaches and their associated complications.

Methods. MEDLINE searches were conducted to collect studies that reported information on patients undergoing VS surgery. The authors set inclusion criteria for such studies, including the availability of follow-up data for at least 3 months, inclusion of preoperative and postoperative audiometric data, intraoperative monitoring, and reporting of results using established and standardized metrics. Data were collected on hearing loss, facial nerve dysfunction, persistent postoperative headache, CSF leak, operative mortality, residual tumor, tumor recurrence, cranial nerve (CN) dysfunction involving nerves other than CN VII or VIII, and other neurological complications. The authors reviewed data from 35 studies pertaining to 5064 patients who had undergone VS surgery.

Results. The analyses for hearing loss and facial nerve dysfunction were stratified into the following tumor categories: intracanalicular (IC), size (extrameatal diameter) < 1.5 cm, size 1.5–3.0 cm, and size > 3.0 cm. The middle cranial fossa approach was found to be superior to the retrosigmoid approach for hearing preservation in patients with tumors < 1.5 cm (hearing loss in 43.6% vs 64.3%, p < 0.001). All other size categories showed no significant difference between middle cranial fossa and retrosigmoid approaches with respect to hearing loss. The retrosigmoid approach was associated with significantly less facial nerve dysfunction in patients with IC tumors than the middle cranial fossa method was; however, neither differed significantly from the translabyrinthine corridor (4%, 16.7%, 0%, respectively, p < 0.001). The middle cranial fossa approach differed significantly from the translabyrinthine approach for patients with tumors < 1.5 cm, whereas neither differed from the retrosigmoid approach (3.3%, 11.5%, and 7.2%, respectively, p = 0.001). The retrosigmoid approach involved less facial nerve dysfunction than the middle cranial fossa or translabyrinthine approaches for tumors 1.5–3.0 cm (6.1%, 17.3%, and 15.8%, respectively; p < 0.001). The retrosigmoid approach was also superior to the translabyrinthine approach for tumors > 3.0 cm (30.2% vs 42.5%, respectively, p < 0.001). Postoperative headache was significantly more likely after the retrosigmoid approach than after the translabyrinthine approach, but neither differed significantly from the middle cranial fossa approach (17.3%, 0%, and 8%, respectively; p < 0.001). The incidence of CSF leak was significantly greater after the retrosigmoid approach than after either the middle cranial fossa or translabyrinthine approaches (10.3%, 5.3%, 7.1%; p = 0.001). The incidences of residual tumor, mortality, major non-CN complications, residual tumor, tumor recurrence, and dysfunction of other cranial nerves were not significantly different across the approaches.

Conclusions. The middle cranial fossa approach seems safest for hearing preservation in patients with smaller tumors. Based on the data, the retrosigmoid approach seems to be the most versatile corridor for facial nerve preservation for most tumor sizes, but it is associated with a higher risk of postoperative pain and CSF fistula. The translabyrinthine approach is associated with complete hearing loss but may be useful for patients with large tumors and poor preoperative hearing.

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C1-C2 Posterior Fixation: Are 4 Screws Better Than 2?

Neurosurgery 71[ONS Suppl 1]:ons86–ons95, 2012 

Several types of C1-C2 fixation techniques have been described over the years in order to treat atlantoaxial instability.

OBJECTIVE: To compare the pros and cons of the most popular C1-C2 posterior fixation used today: C1 lateral mass-C2 pedicle screw and rods (Harms) and transarticular screw (Magerl) fixations.

METHODS: Retrospective review of 122 patients who underwent Harms or Magerl fixation for atlantoaxial instability. Surgical, clinical, and radiological outcomes were compared in the 2 groups.

RESULTS: 123 operations were performed, of which 47 were by the Harms technique (group H) and 76 by the Magerl technique (group M). No significant differences were found in duration of surgery, blood loss, postoperative pain, and length of hospitalization. Postoperatively, neck pain, C2-radiculopathy, and hand function improved in both groups, with better, but not statistically significant, results for group H. The intraoperative complication rate was 2.1% in group H and 21% in group M (P < .05); postoperative complication rate was 10.6% in group H and 21%in groupM(P>.05). The major complications were vertebral artery injury (2.1% in group H, 13.1% in group M, P = .05) and screw fracture (2.1% in group H, 9.2% in group M, P > .05). Fusion rate at the end of follow-up was not significantly higher in group H. C1-C2 range of movements in flexion/extension at the end of follow-up was lower in group H (P = .017).

CONCLUSION: Magerl with posterior wiring and Harms techniques are both effective options for stabilizing the atlantoaxial complex. However, the Harms technique appears to be safer, to have fewer complications, and to demonstrate a more robust long-term fixation.

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Intracranial hypotension producing reversible coma

J Neurosurg 117:615–628, 2012

Intracranial hypotension is a disorder of CSF hypovolemia due to iatrogenic or spontaneous spinal CSF leakage. Rarely, positional headaches may progress to coma, with frequent misdiagnosis. The authors review reported cases of verified intracranial hypotension–associated coma, including 3 previously unpublished cases, totaling 29. Most patients presented with headache prior to neurological deterioration, with positional symptoms elicited in almost half. Eight patients had recently undergone a spinal procedure such as lumbar drainage. Diagnostic workup almost always began with a head CT scan. Subdural collections were present in 86%; however, intracranial hypotension was frequently unrecognized as the underlying cause. Twelve patients underwent one or more procedures to evacuate the collections, sometimes with transiently improved mental status. However, no patient experienced lasting neurological improvement after subdural fluid evacuation alone, and some deteriorated further. Intracranial hypotension was diagnosed in most patients via MRI studies, which were often obtained due to failure to improve after subdural hematoma (SDH) evacuation. Once the diagnosis of intracranial hypotension was made, placement of epidural blood patches was curative in 85% of patients. Twenty-seven patients (93%) experienced favorable outcomes after diagnosis and treatment; 1 patient died, and 1 patient had a morbid outcome secondary to duret hemorrhages. The literature review revealed that numerous additional patients with clinical histories consistent with intracranial hypotension but no radiological confirmation developed SDH following a spinal procedure. Several such patients experienced poor outcomes, and there were multiple deaths. To facilitate recognition of this treatable but potentially life-threatening condition, the authors propose criteria that should prompt intracranial hypotension workup in the comatose patient and present a stepwise management algorithm to guide the appropriate diagnosis and treatment of these patients.

 

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Frameless image-guided stereotaxy with real-time visual feedback for brain biopsy

Acta Neurochir (2012) 154:1663–1667 DOI 10.1007/s00701-012-1425-y

Frame-based stereotaxy remains the “gold standard” for cerebral biopsies and functional neurosurgery though new frameless stereotactic systems are evolving continually. As the technique of frameless stereotaxy gains increasing acceptance among neurosurgeons, this study assesses the feasibility of a system for frameless imageguided stereotaxy.

Methods All patients biopsied for intracranial lesions between February 2007 and August 2010 using the BrainLAB VarioGuide frameless stereotactic system were evaluated prospectively. Prior to surgery, patients underwent magnetic resonance (MR) imaging; additionally, fluoroethyl-tyrosine (FET)-positron emission tomography (PET) images were acquired and fused to MR images in selected cases. Biopsy trajectory length, lesion volume, procedure duration, and diagnostic yield were assessed.

Results Ninety-six diagnostic biopsies in 91 patients were evaluated. Lesion volume ranged from 0.17 to 121.8 cm3; trajectory length from 25.3 to 101.9 mm. Diagnostic yield was 93.8%. Mean operation time from skin incision to wound closure was 42 min; in the operating room, it was 99 min.

Conclusions Clinical experience indicates VarioGuide to be safe and accurate. Reachable range of lesion localisation appears to be comparable to a frame-based stereotaxy system. Operation times are brief. The unique design of this frameless stereotactic system allows real-time visual feedback of needle positioning.

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Long-term Outcomes After Staged-Volume Stereotactic Radiosurgery for Large Arteriovenous Malformations

Neurosurgery 71:632–644, 2012 DOI: 10.1227/NEU.0b013e31825fd247

Stereotactic radiosurgery is an effective treatment modality for small arteriovenous malformations (AVMs) of the brain. For larger AVMs, the treatment dose is often lowered to reduce potential complications, but this decreases the likelihood of cure. One strategy is to divide large AVMs into smaller anatomic volumes and treat each volume separately.

OBJECTIVE: To prospectively assess the long-term efficacy and complications associated with staged-volume radiosurgical treatment of large, symptomatic AVMs.

METHODS: Eighteen patients with AVMs larger than 15 mL underwent prospective staged-volume radiosurgery over a 13-year period. The median AVM volume was 22.9 mL (range, 15.7-50 mL). Separate anatomic volumes were irradiated at 3- to 9-month intervals (median volume, 10.9 mL; range, 5.3-13.4 mL; median marginal dose, 15 Gy; range, 15-17 Gy). The AVM was divided into 2 volumes in 10 patients, 3 volumes in 5 patients, and 4 volumes in 3 patients. Seven patients underwent retreatment for residual disease.

RESULTS: Actuarial rates of complete angiographic occlusion were 29% and 89% at 5 and 10 years. Five patients (27.8%) had a hemorrhage after radiosurgery. Kaplan-Meier analysis of cumulative hemorrhage rates after treatment were 12%, 18%, 31%, and 31% at 2, 3, 5, and 10 years, respectively. One patient died after a hemorrhage (5.6%).

CONCLUSION: Staged-volume radiosurgery for AVMs larger than 15 mL is a viable treatment strategy. The long-term occlusion rate is high, whereas the radiation-related complication rate is low. Hemorrhage during the lag period remains the greatest source of morbidity and mortality.

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Diffusion tensor imaging in hydrocephalus—findings before and after shunt surgery

Acta Neurochir (2012) 154:1699–1706

To evaluate changes in diffusion tensor imaging (DTI)-derived parameters in patients with hydrocephalus (HC) before and several weeks after shunt surgery.

Methods Thirteen HC patients were examined with DTI before and after shunt surgery. In a combined region of interest and whole brain voxel-based analysis, different DTI parameters were compared with an age-matched control group.

Results Alteration of DTI parameters in HC patients and changes after shunt surgery are regionally different. HC patients show an increase in fractional anisotropy values based on increases in parallel diffusivity in the corticospinal tract. On the other hand, reduced fractional anisotropy values are found in the corpus callosum of HC patients. Following shunt surgery, all DTI parameters showed a trend towards normalization, yet differences to healthy control subjects remained.

Conclusion Our results show that DTI parameter changes are regionally dependent and need a careful interpretation of the underlying diffusivities to serve as a diagnostic or follow-up measure in patients with hydrocephalus.

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Technical nuances of resection of giant (> 5 cm) vestibular schwannomas: pearls for success

Neurosurg Focus 33 (3):E15, 2012

Removal of vestibular schwannomas (VSs, or acoustic neuromas) remains one of the most challenging operations in neurosurgery. Giant or huge tumors (> 5 cm) heighten these challenges, and technical nuances play a special role in maximizing tumor resection while minimizing complications.

In this article, the senior author describes his technical experience with microsurgical excision of giant VSs. The accompanying video further illustrates these details.

 

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The Contralateral Transcingulate Approach

Neurosurgery 71[ONS Suppl 1]:ons4–ons14, 2012

The contralateral transcingulate approach is a variation of the contralateral transcallosal approach for lesions located in the cingulate gyrus and deep white matter of the medial frontal lobe.

OBJECTIVE: To more thoroughly describe the contralateral transcingulate approach by reporting our operative technique and results.

METHODS: This approach positions the head with the midline horizontally, lesion on the upside, allowing gravity retraction of the dependent frontal lobe. Bifrontal craniotomy and splitting of the interhemispheric fissure create a crossing trajectory from the contralateral fissure to the ipsilateral cingulate gyrus that maximizes lateral exposure.

RESULTS: Eleven patients with vascular lesions were treated with the contralateral transcingulate approach (9 patients with cavernous malformations and 2 patients with arteriovenous malformations). Eight lesions were located on the left side, 5 in the cingulate gyrus, and 6 in the deep frontal lobe. The falx was cut in 5 patients to extend the crossing trajectory. All lesions were removed completely, with neurological morbidity in 1 patient caused by venous infarction.

CONCLUSION: Although similar to the contralateral transcallosal approach, the contralateral transcingulate approach accesses lesions outside the ventricle and has a steeper crossing trajectory. This approach requires no disruption of brain tissue with lesions on the cingulate surface and only a small incision in cingulate gyrus with lesions in the deep frontal lobe. The ipsilateral pericallosal and callosomarginal arteries provide dependable landmarks for transcingulate dissection. The contralateral transcingulate approach offers an alternative medial approach to lesions near language and motor areas and avoids lateral transcortical approaches, awake speech mapping, and risk to eloquent cortex in the dominant hemisphere.

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Natural history of DAVFs without cortical venous drainage

J Neurosurg 117:539–545, 2012

The goal of this study was to determine the clinical course of Borden-Shucart Type I cranial dural arteriovenous fistulas (DAVFs) and to calculate the annual rate of conversion of these lesions to more aggressive fistulas that have cortical venous drainage (CVD).

Methods. A retrospective chart review was conducted of all patients harboring DAVFs who were seen at the authors’ institution between 1997 and 2009. Twenty-three patients with Type I DAVFs who had available clinical follow-up were identified. Angiographic and clinical data from these patients were reviewed. Neurological outcome and status of presenting symptoms were assessed during long-term follow-up.

Results. Of the 23 patients, 13 underwent endovascular treatment for intolerable tinnitus or ophthalmological symptoms, and 10 did not undergo treatment. Three untreated patients died of unrelated causes. In those who were treated, complete DAVF obliteration was achieved in 4 patients, and palliative reduction in DAVF flow was achieved in 9 patients. Of the 19 patients without radiographic cure, no patient developed intracranial hemorrhage or nonhemorrhagic neurological deficits (NHNDs), and no patient died of DAVF-related causes over a mean follow-up of 5.6 years. One patient experienced a spontaneous, asymptomatic obliteration of a partially treated DAVF in late follow-up, and 2 patients experienced a symptomatic conversion of their DAVF to a higher-grade fistula with CVD in late follow-up. The annual rate of conversion to a higher-grade DAVF based on Kaplan-Meier cumulative event-free survival analysis was 1.0%. The annual rate of intracranial hemorrhage, NHND, and DAVF-related death was 0.0%.

Conclusions. A small number of Type I DAVFs will convert to more aggressive DAVFs with CVD over time. This conversion to a higher-grade DAVF is typically heralded by a change in patient symptoms. Follow-up vascular imaging is important, particularly in the setting of recurrent or new symptoms.

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Assessment of a Quick Reference Table Algorithm for Determining Initial Postoperative Pressure Settings of Programmable Pressure Valves in Patients With Idiopathic Normal Pressure Hydrocephalus: SINPHONI Subanalysis

Neurosurgery 71:722–728, 2012 

Management of overdrainage complications in shunted patients with idiopathic normal pressure hydrocephalus (INPH) remains a difficult task despite the use of programmable pressure valves.

OBJECTIVE: To assess the usefulness of a quick reference table (QRT) algorithm for achieving a suitable initial programmable pressure valve setting in INPH patients who participated in the Study for INPH on Neurological Improvement (SINPHONI).

METHODS: One hundred registered patients diagnosed with probable INPH were treated with ventriculoperitoneal shunts using Codman-Hakim programmable valves (CHPVs). In this series, the initial CHPV setting was decided prospectively according to the QRT algorithm. Shunt effectiveness, complications, and the number of CHPV readjustments during follow-up periods were investigated.

RESULTS: Eighty patients were considered better than shunt responders (more than 1 point improvement in modified Rankin Scale at any follow-up period). Readjustments of CHPVs within 3 months after treatment with ventriculoperitoneal shunt were performed 56 times in 44 cases (44%, 0.56 times/patient). Low-pressure headache occurred in 9 patients, all of whom improved by readjustment alone. Nontraumatic subdural fluid collections and chronic subdural hematomas occurred in 15 cases (15%); however, most of the cases were subclinical and improved after CHPV readjustments alone. Burr hole irrigation was necessary in only 1 case.

CONCLUSION: Use of the QRT algorithm was associated with a decrease in postoperative CHPV readjustments and serious overdrainage complications during the followup period. The QRT algorithm is an easy, safe, and effective method for determining the initial CHPV pressure setting in INPH patients.

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Patients with idiopathic trigeminal neuralgia have a sharper-than-normal trigeminal-pontine angle and trigeminal nerve atrophy

Acta Neurochir (2012) 154:1627–1633

Trigeminal neuralgia (TN) is primarily diagnosed by symptoms and patient history. Magnetic resonance (MR) imaging can be helpful in visualizing the neurovascular compression of the trigeminal nerve in TN patients, but the current parameters used as diagnostic markers for TN are less than optimal. The aim of this study is to assess whether the angle between the trigeminal nerve and the pons (the trigeminal-pontine angle) on the affected side of patients with idiopathic TN differs from that of the unaffected side and that found in controls without TN.

Methods A case-control study of 30 clinically diagnosed idiopathic TN patients aged 30 to 79 years and 30 age- and sexmatched controls was conducted.We compared the trigeminalpontine angle and trigeminal nerve atrophy via fast-imaging employing steady-state acquisition (FIESTA) MR imaging.

Results A sharp trigeminal-pontine angle was observed in 25 patients (25/30) on the affected side. As such, the mean angle of the trigeminal nerve on the affected side (40.17) was significantly smaller than that on the unaffected side (48.91, p=0.001) and that in the control group (52.02, p<0.001).

Conclusions A sharp trigeminal-pontine angle on the affected side was found in idiopathic TN patients by FIESTA imaging. This suggests that a sharp trigeminal-pontine angle increases the chance of neurovascular compression on the medial side of the trigeminal nerve.

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The Impact of Standing Regional Cervical Sagittal Alignment on Outcomes in Posterior Cervical Fusion Surgery

Neurosurgery 71:662–669, 2012

Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.

OBJECTIVE: To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.

METHODS: From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-oflife scores.

RESULTS: Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r = -0.43, P <.001 and r = -0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.

CONCLUSION: Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.

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A randomized study of urgent computed tomography–based hematoma puncture and aspiration in the emergency department and subsequent evacuation using craniectomy versus craniectomy only

J Neurosurg 117:566–573, 2012

When treating patients with a spontaneous supratentorial massive (≥ 70 ml) intracerebral hemorrhage (ICH), the results of surgery are gloomy. A worsening pupil response has been observed in patients preoperatively, despite blood pressure control and diuretic administration. Because open surgery needs time for decompression to occur, the authors conducted a prospective randomized study to determine whether patients who have suffered a massive ICH can benefit from a more urgently performed decompressive procedure.

Methods. Overall, 36 eligible patients admitted 6 or fewer hours post-ictus were enrolled in the study. In Group A, 12 patients underwent CT-based hematoma puncture and partial aspiration in the emergency department (ED) and subsequent evacuation via a craniectomy; in Group B, 24 patients underwent hematoma evacuation via a craniectomy only. Pupil responses were categorized into 5 grades (Grade 0, bilaterally fixed; Grade 1, unilaterally fixed with the fixed pupil > 7 mm; Grade 2, unilaterally fixed with the fixed pupil ≤ 7 mm; Grade 3, a unilaterally sluggish response; and Grade 4, a bilaterally brisk response). Grades were obtained on admission, at surgical decompression (defined as the point at which liquid hematoma began to flow out in Group A and at dural opening in Group B), and at completion of craniectomy. The Barthel Scale was used to assess survivors’ functional outcome at 12 months. Comparisons were made between Groups A and B. Logistic regression analysis was used to evaluate the positive likelihood ratio of all variables for survival and function (Barthel Scale score of ≥ 35 at 12 months).

Results. Decompressive surgery was undertaken approximately 60 minutes earlier in Group A than B. A worsening pupil reflex before decompression was observed in no Group A patient and in 9 Group B patients. At the time of decompression pupil response was better in Group A than B (p < 0.05). Although only approximately one-third of the hematoma volume documented on initial CT scanning had been drained before the craniectomy in Group A, when partial aspiration was followed by craniectomy, better pupil-response results were obtained in Group A at the completion of craniectomy, and survival rate and 12-month Barthel Scale score were better as well (p < 0.05). Logistic regression analysis revealed that one variable, a minimum pupil grade of 3 at the time of decompression, had the highest predictive value for survival at 12 months (8.0, 95% CI 2.0–32.0), and a pupil grade of 4 at the same time was the most valuable predictor of a Barthel Scale score of 35 or greater at 12 months (15.0, 95% CI 1.9–120.9).

Conclusions. Patients with massive spontaneous supratentorial ICHs may benefit from more urgent surgical decompression. The results of logistic regression analysis implied that, to improve long-term functional outcome, decompression should be performed in patients before herniation occurs. Due to the fact that most of these patients have signs of herniation when presenting to the ED and because conventional surgical decompression requires time to take effect, this combination of surgical treatment provides a feasible and effective surgical option.

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