Month: October 2011

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Postoperative Infection May Influence Survival in Patients With Glioblastoma: Simply a Myth?

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.

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Cell Surface Receptors in Malignant Glioma

Neurosurgery 69:980–994, 2011 DOI: 10.1227/NEU.0b013e318220a672

Despite advances in surgery, radiation, and chemotherapy, malignant gliomas are still highly lethal tumors. Traditional treatments that rely on nonspecific, cytotoxic approaches have a marginal impact on patient survival.

However, recent advances in the molecular cancer biology underlying glioma pathogenesis have revealed that abnormalities in common cell surface receptors, including receptor tyrosine kinase and other cytokines, mediate the abnormal cellular signal pathways and aggressive biological behavior among the majority of these tumors.

Some cell surface receptors have been targeted by novel agents in preclinical and clinical development. Such cancer-specific targeted agents might offer the promise of improved cancer control without substantial toxicity.

Here, we review these common cell surface receptors with clinical significance for malignant glioma and discuss the molecular characteristics, pathological significance, and potential therapeutic application of these cell surface receptors.

We also summarize the clinical trials of drugs targeting these cell surface receptors in malignant glioma patients.

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Minimally invasive lateral lumbar interbody fusion and transpsoas approach–related morbidity

Neurosurgical Focus Oct 2011 / Vol. 31 / No. 4 / Page E4

Recently, the minimally invasive, lateral retroperitoneal, transpsoas approach to the thoracolumbar spinal column has been described by various authors. This is known as the minimally invasive lateral lumbar interbody fusion. The purpose of this study is to elucidate the approach-related morbidity associated with the minimally invasive transpsoas approach to the lumbar spine. To date, there have been only a couple of reports regarding the morbidity of the transpsoas muscle approach.

METHODS

A nonrandomized, prospective study utilizing a self-reported patient questionnaire was conducted between January 2006 and June 2008 at Northwestern University. Data were collected in 53 patients with a follow-up period ranging from 6 months to 3.5 years. Only 2 patients were lost to follow-up.

RESULTS

Thirty-six percent (19 of 53) of patients reported subjective hip flexor weakness, 25% (13 of 53) anterior thigh numbness, and 23% (12 of 53) anterior thigh pain. However, 84% of the 19 patients reported complete resolution of their subjective hip flexor weakness by 6 months, and most experienced improved strength by 8 weeks. Of those reporting anterior thigh numbness and pain, 69% and 75% improved to their baseline function by the 6-month follow-up evaluations, respectively. All patients with self-reported subjective hip flexor weakness underwent examinations during subsequent clinic visits after surgery; however, these examinations did not confirm a motor deficit less than Grade 5. Subset analysis showed that the L3–4 and L4–5 levels were most often affected.

CONCLUSIONS

The minimally invasive, transpsoas muscle approach to the lumbar spine has a number of advantages. The data show that a percentage of the patients undergoing the transpsoas approach will have temporary sensory and motor symptoms related to this approach. The majority of the symptoms are thought to be related to psoas muscle inflammation and/or stretch injury to the genitofemoral nerve due to the surgical corridor traversed during the operation. No major injuries to the lumbar plexus were encountered. It is important to educate patients prior to surgery of the possibility of these largely transient symptoms.

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Superciliary keyhole surgery for unruptured posterior communicating artery aneurysms with oculomotor nerve palsy: maximizing symptomatic resolution and minimizing surgical invasiveness

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.

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Surgical treatment of thoracic disc herniations via tailored posterior approaches

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.

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Dentatorubrothalamic tract in human brain: diffusion tensor tractography study

Neuroradiology (2011) 53:787–791.DOI 10.1007/s00234-011-0878-7
The dentatorubrothalamic tract (DRTT) originates from the dentate nucleus in the cerebellum and terminates in the contralateral ventrolateral nucleus (VL) of the thalamus after decussating to the contralateral red nucleus. Identification of the DRTT is difficult due to the fact that it is a long, multisynaptic, neural tract crossing to the opposite hemisphere. In the current study, we attempted to identify the DRTT in the human brain using a probabilistic tractography technique of diffusion tensor imaging.
Methods Diffusion tensor imaging was performed at 1.5-T using a synergy-L sensitivity encoding head coil. DRTTs were obtained by selection of fibers passing through three regions of interest (the dentate nucleus, the superior cerebellar peduncle, and the contralateral red nucleus) from 41 healthy volunteers. Probabilistic mapping was obtained from the highest probabilistic location at 2.3 mm above the anterior commissure–posterior commissure level.
Results DRTTs of all subjects, which originated from the dentate nucleus, ascended through the junction of the superior cerebellar peduncle and the contralateral red nucleus and then terminated at the VL nucleus of the thalamus. The highest probabilistic location for the DRTT at the thalamus was compatible with the location of the VL nucleus.
Conclusions We identified the DRTT in the human brain using probabilistic tractography. Our results could be useful in research on movement control.

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Accuracy of Image-Guided Pedicle Screw Placement Using Intraoperative Computed Tomography- Based Navigation With Automated Referencing, Part I: Cervicothoracic Spine

Neurosurgery 69:782–795, 2011 DOI: 10.1227/NEU.0b013e318222ae16

Image-guided spinal instrumentation reduces the incidence of implant misplacement.

OBJECTIVE: To assess the accuracy of intraoperative computed tomography (iCT)-based neuronavigation (iCT-N).

METHODS: In 35 patients (age range, 18-87 years), a total of 248 pedicle screws were placed in the cervical (C1-C7) and upper and midthoracic (T1-T8) spine. An automated iCT registration sequence was used for multisegmental instrumentation, with the reference frame fixed to either a Mayfield head clamp and/or the most distal spinous process within the instrumentation. Pediculation was performed with navigated drill guides or Jamshidi cannulas. The angular deviation between navigated tool trajectory and final implant positions (evaluated on postinstrumentation iCT or postoperative CT scans) was calculated to assess the accuracy of iCT-N. Final screw positions were also graded according to established classification systems. Mean follow-up was 16.7 months.

RESULTS: Clinically significant screw misplacement or iCT-N failure mandating conversion to conventional technique did not occur. A total of 71.4% of patients self-rated their outcome as excellent or good at 12 months; 99.3% of cervical screws were compliant with Neo classification grades 0 and 1 (grade 2, 0.7%), and neurovascular injury did not occur. In addition, 97.8% of thoracic pedicle screws were assigned grades I to III of the Heary classification, with 2.2% grade IV placement. Accuracy of iCT-N progressively deteriorated with increasing distance from the spinal reference clamp but allowed safe instrumentation of up to 10 segments.

CONCLUSION: Image-guided spinal instrumentation using iCT-N with automated referencing allows safe, highly accurate multilevel instrumentation of the cervical and upper and midthoracic spine. In addition, iCT-N significantly reduces the need for reregistration in multilevel surgery.

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Fiducial Registration With Spoiled Gradient-Echo Magnetic Resonance Imaging Enhances the Accuracy of Subthalamic Nucleus Targeting

Neurosurgery 69:870–875, 2011 DOI: 10.1227/NEU.0b013e318222ae33

A variety of imaging strategies may be used to derive reliable stereotactic coordinates when performing deep brain stimulation lead implants. No single technique has yet proved optimal.

OBJECTIVE: To compare the relative accuracy of stereotactic coordinates for the subthalamic nucleus (STN) derived either from fast spin echo/inversion recovery (FSE/IR) magnetic resonance imaging MRI alone (group 1) or FSE/IR in conjunction with T1- weighted spoiled gradient-echo MRI (group 2).

METHODS: A retrospective analysis of 145 consecutive STN deep brain stimulation lead placements (group 1, n = 72; group 2, n = 73) was performed in 81 Parkinson disease patients by 1 surgical team. From the operative reports, we recorded the number of microelectrode recording trajectories required to localize the desired STN target and the span of STN traversed along the implantation trajectory. In addition, we calculated the 3-dimensional vector difference between the initial MRI-derived coordinates and the final physiologically refined coordinates.

RESULTS: The proportion of implants completed with just 1 microelectrode recording trajectory was greater (81% vs 58%; P < .001) and the 3-dimensional vector difference between the anatomically selected target and the microelectrode recording–refined target was smaller (0.6 ± 1.2 vs 0.9 ± 1.3; P = .04) in group 2 than in group 1. At the same time, the mean expanse of STN recorded along the implantation trajectory was 8% greater in group 2 (4.8 ± 0.6 vs 5.2 ± 0.6 mm; P < .001).

CONCLUSION: A combination of stereotactic FSE/IR and spoiled gradient-echo MRI yields more accurate coordinates for the STN than FSE/IR MRI alone.

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Bilateral subfrontal approach for tuberculum sellae meningiomas in long-term postoperative visual outcome

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.

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Quantification of Glioma Removal by Intraoperative High-Field Magnetic Resonance Imaging: An Update

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.

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Intraoperative confocal microscopy in the visualization of 5-aminolevulinic acid fluorescence in low-grade gliomas

J Neurosurg 115:740–748, 2011. DOI: 10.3171/2011.6.JNS11252

Greater extent of resection (EOR) for patients with low-grade glioma (LGG) corresponds with improved clinical outcome, yet remains a central challenge to the neurosurgical oncologist. Although 5-aminolevulinic acid (5- ALA)–induced tumor fluorescence is a strategy that can improve EOR in gliomas, only glioblastomas routinely fluoresce following 5-ALA administration. Intraoperative confocal microscopy adapts conventional confocal technology to a handheld probe that provides real-time fluorescent imaging at up to 1000× magnification. The authors report a combined approach in which intraoperative confocal microscopy is used to visualize 5-ALA tumor fluorescence in LGGs during the course of microsurgical resection.

Methods. Following 5-ALA administration, patients with newly diagnosed LGG underwent microsurgical resection. Intraoperative confocal microscopy was conducted at the following points: 1) initial encounter with the tumor; 2) the midpoint of tumor resection; and 3) the presumed brain-tumor interface. Histopathological analysis of these sites correlated tumor infiltration with intraoperative cellular tumor fluorescence.

Results. Ten consecutive patients with WHO Grades I and II gliomas underwent microsurgical resection with 5-ALA and intraoperative confocal microscopy. Macroscopic tumor fluorescence was not evident in any patient. However, in each case, intraoperative confocal microscopy identified tumor fluorescence at a cellular level, a finding that corresponded to tumor infiltration on matched histological analyses.

Conclusions. Intraoperative confocal microscopy can visualize cellular 5-ALA–induced tumor fluorescence within LGGs and at the brain-tumor interface. To assess the clinical value of 5-ALA for high-grade gliomas in conjunction with neuronavigation, and for LGGs in combination with intraoperative confocal microscopy and neuronavigation, a Phase IIIa randomized placebo-controlled trial (BALANCE) is underway at the authors’ institution.

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Intraoperative magnetic resonance imaging findings during deep brain stimulation surgery

J Neurosurg 115:852–857, 2011.DOI: 10.3171/2011.5.JNS101457

Deep brain stimulation (DBS) is an established neurosurgical technique used to treat a variety of neurological disorders, including Parkinson disease, essential tremor, dystonia, epilepsy, depression, and obsessive-compulsive disorder. This study reports on the use of intraoperative MR imaging during DBS surgery to evaluate acute hemorrhage, intracranial air, brain shift, and accuracy of lead placement.

Methods. During a 46-month period, 143 patients underwent 152 DBS surgeries including 289 lead placements utilizing intraoperative 1.5-T MR imaging. Imaging was supervised by an MR imaging physicist to maintain the specific absorption rate below the required level of 0.1 W/kg and always included T1 magnetization-prepared rapid gradient echo and T2* gradient echo sequences with selected use of T2 fluid attenuated inversion recovery (FLAIR) and T2 fast spin echo (FSE). Retrospective review of the intraoperative MR imaging examinations was performed to quantify the amount of hemorrhage and the amount of air introduced during the DBS surgery.

Results. Intraoperative MR imaging revealed 5 subdural hematomas, 3 subarachnoid hemorrhages, and 1 intraparenchymal hemorrhage in 9 of the 143 patients. Only 1 patient experiencing a subarachnoid hemorrhage developed clinically apparent symptoms, which included transient severe headache and mild confusion. Brain shift due to intracranial air was identified in 144 separate instances.

Conclusions. Intraoperative MR imaging can be safely performed and may assist in demonstrating acute changes involving intracranial hemorrhage and air during DBS surgery. These findings are rarely clinically significant and typically resolve prior to follow-up imaging. Selective use of T2 FLAIR and T2 FSE imaging can confirm the presence of hemorrhage or air and preclude the need for CT examinations

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Occipital WHO grade II gliomas: oncological, surgical and functional considerations

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.

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Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis

Eur Spine J (2011) 20:1596–1606.DOI 10.1007/s00586-011-1873-8
Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a meta-analysis of all systematic reviews, randomized clinical trials and prospective cohort series to quantify the effectiveness of IPDs and to evaluate the potential sideeffects.
Methods  Data from all studies prospectively describing clinical results based on validated outcome scales and reporting complications of treatment of patients with INC with IPD placement. We searched MEDLINE, EMBASE, Web of Science, Cochrane (CENTRAL), CINAHL, Academic Search Premier, Science Direct up to July 2010. Studies describing patients with INC caused by lumbar stenosis, reporting complication rate and reporting based on validated outcome scores, were eligible. Studies with only instrumented IPD results were excluded.
Results  Eleven studies eligible studies were identified. Two independently RCTs and eight prospective cohorts were available. In total 563 patients were treated with IPDs. All studies showed improvement in validated outcome scores after 6 weeks and 1 year. Pooled data based on the Zurich Claudication Questionnaire of the RCTs were more in favor of IPD treatment compared with conservative treatment (pooled estimate 23.2, SD 18.5–27.8). Statistical heterogeneity after pooled data was low (I-squared 0.0, p =  0.930). Overall complication rate was 7%.
Conclusion  As the evidence is relatively low and the costs are high, more thorough (cost-) effectiveness studies should be performed before worldwide implementation is introduced.

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Dentatorubrothalamic tract in human brain: diffusion tensor tractography study

Neuroradiology(2011)53:787–791.DOI 10.1007/s00234-011-0878-7
The dentatorubrothalamic tract (DRTT) originates  from the dentate nucleus in the cerebellum and terminates in the contralateral ventrolateral nucleus (VL) of the thalamus after decussating to the contralateral red nucleus. Identification of the DRTT is difficult due to the fact that it is a long, multisynaptic, neural tract crossing to the opposite hemisphere.
In the current study, we attempted to identify the DRTT in the human brain using a probabilistic tractography technique of diffusion tensor imaging.
Methods Diffusion tensor imaging was performed at 1.5-T using a synergy-L sensitivity encoding head coil. DRTTs were obtained by selection of fibers passing through three regions of interest (the dentate nucleus, the superior cerebellar peduncle, and the contralateral red nucleus) from 41 healthy volunteers. Probabilistic mapping was obtained from the highest probabilistic location at 2.3 mm above the anterior commissure–posterior commissure level.
Results DRTTs of all subjects, which originated from the dentate nucleus, ascended through the junction of the superior cerebellar peduncle and the contralateral red nucleus and then terminated at the VL nucleus of the thalamus. The highest probabilistic location for the DRTT at the thalamus was compatible with the location of the VL nucleus.
Conclusions We identified the DRTT in the human brain using probabilistic tractography. Our results could be useful in research on movement control.

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Tubular Diskectomy vs Conventional Microdiskectomy for the Treatment of Lumbar Disk-Related Sciatica: Cost Utility Analysis Alongside a Double-Blind Randomized Controlled Trial

Neurosurgery 69:829–836, 2011 DOI: 10.1227/NEU.0b013e31822578f6

Conventional microdiskectomy is the most frequently performed surgery for patients with sciatica caused by lumbar disk herniation. Transmuscular tubular diskectomy has been introduced to increase the rate of recovery, although evidence of its efficacy is lacking.

OBJECTIVE: To determine whether a favorable cost-effectiveness for tubular diskectomy compared with conventional microdiskectomy is attained.

METHODS: Cost utility analysis was performed alongside a double-blind randomized controlled trial conducted among 325 patients with lumbar disk related sciatica lasting .6 to 8 weeks at 7 Dutch hospitals comparing tubular diskectomy with conventional microdiskectomy. Main outcome measures were quality-adjusted life-years at 1 year and societal costs, estimated from patient reported utilities (US and Netherlands EuroQol, Short Form Health Survey-6D, and Visual Analog Scale) and diaries on costs (health care, patient costs, and productivity).

RESULTS: Quality-adjusted life-years during all 4 quarters and according to all utility measures were not statistically different between tubular diskectomy and conventional microdiskectomy (difference for US EuroQol, 20.012; 95% confidence interval, 20.046 to 0.021). From the healthcare perspective, tubular diskectomy resulted in nonsignificantly higher costs (difference US $460; 95% confidence interval, 2243 to 1163). From the societal perspective, a nonsignificant difference of US $1491 (95% confidence interval, 21335 to 4318) in favor of conventional microdiskectomy was found. The nonsignificant differences in costs and quality-adjusted life-years in favor of conventional microdiskectomy result in a low probability that tubular diskectomy is more cost-effective than conventional microdiskectomy.

CONCLUSION: Tubular diskectomy is unlikely to be cost-effective compared with conventional microdiskectomy.

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Neurosurgery and shaving: what’s the evidence?. A review

Journal of Neurosurgery Oct 2011 / Vol. 115 / No. 4 / Pages 670-678. DOI: 10.3171/2011.5.JNS102003.

Many neurosurgeons remove their patients’ hair before surgery. They claim that this practice reduces the chance of postoperative surgical site infections, and facilitates planning, attachment of the drapes, and closure. However, most patients dread this procedure.

The authors performed the first systematic review on shaving before neurosurgical procedures to investigate whether this commonly performed procedure is based on evidence. They systematically reviewed the literature on wound infections following different shaving strategies. Data on the type of surgery, surgery-related infections, preoperative shaving policy, decontamination protocols, and perioperative antibiotics protocols were collected.

The search detected 165 articles, of which 21 studies—involving 11,071 patients—were suitable for inclusion. Two of these studies were randomized controlled trials. The authors reviewed 13 studies that reported on the role of preoperative hair removal in craniotomies, 14 on implantation surgery, 5 on bur hole procedures, and 3 on spine surgery. Nine studies described shaving policies in pediatric patients.

None of these papers provided evidence that preoperative shaving decreases the occurrence of postoperative wound infections. The authors conclude that there is no evidence to support the routine performance of preoperative hair removal in neurosurgery. Therefore, properly designed studies are needed to provide evidence for preoperative shaving recommendations.

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Prospective, randomized, multicenter study of cervical arthroplasty: 269 patients from the Kineflex|C artificial disc investigational device exemption study with a minimum 2-year follow-up

Journal of Neurosurgery: Spine Oct 2011 / Vol. 15 / No. 4 / Pages 348-358. DOI: 10.3171/2011.5.SPINE10769.

Cervical total disc replacement (CTDR) represents a relatively novel procedure intended to address some of the shortcomings associated with anterior cervical discectomy and fusion (ACDF) by preserving motion at the treated level. This prospective, randomized, multicenter study evaluates the safety and efficacy of a new metal-on-metal CTDR implant (Kineflex|C) by comparing it with ACDF in the treatment of single-level spondylosis with radiculopathy.

METHODS

The study was a prospective, randomized US FDA Investigational Device Exemption (IDE) pivotal trial conducted at 21 centers across the US. The primary clinical outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS) scores, and a composite measure of clinical success. Patients were randomized to CTDR using the Kineflex|C (SpinalMotion, Inc.) cervical artificial disc or ACDF using structural allograft and an anterior plate.

RESULTS

A total of 269 patients were enrolled and randomly assigned to either CTDR (136 patients) or to ACDF (133 patients). There were no significant differences between the CTDR and ACDF groups when comparing operative time, blood loss, length of hospital stay, or the reoperation rate at the index level. The overall success rate was significantly greater in the CTDR group (85%) compared with the ACDF group (71%) (p = 0.05). In both groups, the mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the 24-month follow-up (p < 0.0001). Similarly, the VAS pain scores improved significantly by 6 weeks and remained significantly improved through the 24-month follow-up (p < 0.0001). The range of motion (ROM) in the CTDR group decreased at 3 months but was significantly greater than the preoperative mean at 12- and 24-month follow-up. The ROM in the ACDF group was significantly reduced by 3 months and remained so throughout the follow-up. Adjacent-level degeneration was also evaluated in both groups from preoperatively to 2-year follow-up and was classified as none, mild, moderate, or severe. Preoperatively, there were no significant differences between groups when evaluating the different levels of adjacent-level degeneration. At the 2-year follow-up, there were significantly more patients in the ACDF group with severe adjacent-level radiographic changes (p < 0.0001). However, there were no significant differences between groups in adjacent-level reoperation rate (7.6% for the Kineflex|C group and 6.1% for the ACDF group).

CONCLUSIONS

Cervical total disc replacement allows for neural decompression and clinical results comparable to ACDF. Kineflex|C was associated with a significantly greater overall success rate than fusion while maintaining motion at the index level. Furthermore, there were significantly fewer Kineflex|C patients showing severe adjacent-level radiographic changes at the 2-year follow-up. These results from a prospective, randomized study support that Kineflex|C CTDR is a viable alternative to ACDF in select patients with cervical radiculopathy

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Management of Adult Hydrocephalus With Ventriculoperitoneal Shunts: Long-term Single- Institution Experience

Neurosurgery 69:774–781, 2011 DOI: 10.1227/NEU.0b013e31821ffa9e

Ventriculoperitoneal shunting is the most widely used neurosurgical procedure for the management of hydrocephalus.

OBJECTIVE: To evaluate our long-term single-institution experience in the management of adult hydrocephalus patients with ventriculoperitoneal shunts.

METHODS: Adult patients who underwent ventriculoperitoneal shunt placement for hydrocephalus from October 1990 to October 2009 were included. Medical charts, operative reports, imaging studies, and clinical follow-up evaluations were reviewed and analyzed retrospectively for clinical outcome in adult hydrocephalus patients.

RESULTS: A total of 683 adult patients were included in the study. The most common etiologies of hydrocephalus include idiopathic (29%), tumors and cysts (20%), postcraniotomy (13%), and subarachnoid hemorrhage (13%). The overall shunt failure rate was 32%, and the majority (74%) of shunt revisions occurred within the first 6 months. The median time to first shunt revision was 9.31 months. Etiology of hydrocephalus showed a significant impact on the incidence of shunt revision/failure and on the median time to shunt revision. Similarly, the type of hydrocephalus had a significant effect on the incidence of shunt failure and the median time to shunt revision.

CONCLUSION: A large proportion of patients (32%) experience shunt failure after shunt placement for hydrocephalus. Although the overall incidence of shunt revision was comparable to previously reported studies, the fact that a large proportion of adult populations with shunt placement experience shunt failure is a concern.

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A Proposed Grading System of Brain and Spinal Cavernomas

Neurosurgery 69:807–814, 2011 DOI: 10.1227/NEU.0b013e31821ffbb5
Most cavernomas in the central nervous system are characterized by a benign natural course. Progressive symptoms warrant surgical removal. In the literature, the factors affecting long-term postoperative outcome are not statistically well confirmed.
OBJECTIVE: To perform a multifactorial analysis of risk factors on a large patient series and to use the results to propose a simple grading scale to predict outcome.
METHODS: We studied 303 consecutive patients with cavernomas treated surgically at our department from 1980 to 2009. Follow-up assessment was performed on average 5.7 years postoperatively (range, 0.2-36 years). The main outcome measure was the patients’ condition at the last follow-up on Glasgow Outcome Scale. For statistical analysis, the outcome measure was dichotomized to favorable (Glasgow Outcome Scale 5) and unfavorable (Glasgow Outcome Scale 1-4). Binary logistic regression analysis was used to estimate the effect of age, sex, seizures, preexisting neurological deficits, hemorrhage, and size and location of cavernoma on long-term outcome.
RESULTS: Infratentorial, basal ganglia, or spinal location and preexisting neurological deficit were the only independent risk factors for unfavorable outcome, with relative risks of 2.7 (P = .008) and 3.2 (P = .002), respectively. We formulated a grading system based on a score of 1 to 3. When applied to our series, the proposed grading system strongly correlated with outcome (P < .001, Pearson x2 test). The risk for long-term unfavorable outcome was 13%, 22%, and 55% for grades 1 through 3, respectively.
CONCLUSION: The proposed grading system showed a convincing correlation with postoperative outcome in surgically treated cavernoma patients.
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