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Fiber tracts of the dorsal language stream in the human brain

Fiber tracts of the dorsal language stream in the human brain

J Neurosurg 124:1396–1405, 2016

The aim of this study was to examine the arcuate (AF) and superior longitudinal fasciculi (SLF), which together form the dorsal language stream, using fiber dissection and diffusion imaging techniques in the human brain.

Methods Twenty-five formalin-fixed brains (50 hemispheres) and 3 adult cadaveric heads, prepared according to the Klingler method, were examined by the fiber dissection technique. The authors’ findings were supported with MR tractography provided by the Human Connectome Project, WU-Minn Consortium. The frequencies of gyral distributions were calculated in segments of the AF and SLF in the cadaveric specimens.

Results The AF has ventral and dorsal segments, and the SLF has 3 segments: SLF I (dorsal pathway), II (middle pathway), and III (ventral pathway). The AF ventral segment connects the middle (88%; all percentages represent the area of the named structure that is connected to the tract) and posterior (100%) parts of the superior temporal gyri and the middle part (92%) of the middle temporal gyrus to the posterior part of the inferior frontal gyrus (96% in pars opercularis, 40% in pars triangularis) and the ventral premotor cortex (84%) by passing deep to the lower part of the supramarginal gyrus (100%). The AF dorsal segment connects the posterior part of the middle (100%) and inferior temporal gyri (76%) to the posterior part of the inferior frontal gyrus (96% in pars opercularis), ventral premotor cortex (72%), and posterior part of the middle frontal gyrus (56%) by passing deep to the lower part of the angular gyrus (100%).

Conclusions This study depicts the distinct subdivision of the AF and SLF, based on cadaveric fiber dissection and diffusion imaging techniques, to clarify the complicated language processing pathways.

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Fiber tracking for temporal tumors

Distinct displacements of the optic radiation based on tumor location revealed using preoperative diffusion tensor imaging

J Neurosurg 124:1343–1352, 2016

Visual field defects (VFDs) due to optic radiation (OR) injury are a common complication of temporal lobe surgery. The authors analyzed whether preoperative visualization of the optic tract would reduce this complication by influencing the surgeon’s decisions about surgical approaches. The authors also determined whether white matter shifts caused by temporal lobe tumors would follow predetermined patterns based on the tumor’s topography.

Methods One hundred thirteen patients with intraaxial tumors of the temporal lobe underwent preoperative diffusion tensor imaging (DTI) fiber tracking. In 54 of those patients, both pre- and postoperative VFDs were documented using computerized perimetry. Brainlab’s iPlan 2.5 navigation software was used for tumor reconstruction and fiber visualization after the fusion of DTI studies with their respective magnetization-prepared rapid gradient-echo (MP-RAGE) images. The tracking algorithm was as follows: minimum fiber length 100 mm, fractional anisotropy threshold 0.1. The lateral geniculate body and the calcarine cortex were employed as tract seeding points. Shifts of the OR caused by tumor were visualized in comparison with the fiber tracking of the patient’s healthy hemisphere.

Results Temporal tumors produced a dislocation of the OR but no apparent fiber destruction. The shift of white matter tracts followed fixed patterns dependent on tumor location: Temporolateral tumors resulted in a medial fiber shift, and thus a lateral transcortical approach is recommended. Temporopolar tumors led to a posterior shift, always including Meyer’s loop; therefore, a pterional transcortical approach is recommended. Temporomesial tumors produced a lateral and superior shift; thus, a transsylvian-transcisternal approach will result in maximum sparing of the fibers. Temporocentric tumors also induced a lateral fiber shift. For those tumors, a transsylvian-transopercular approach is recommended. Tumors of the fusiform gyrus generated a superior (and lateral) shift; consequently, a subtemporal approach is recommended to avoid white matter injury. In applying the approaches recommended above, new or worsened VFDs occurred in 4% of the patient cohort. Total neurological and surgical morbidity were less than 10%. In 90% of patients, gross-total resection was accomplished.

Conclusions Preoperative visualization of the OR may help in avoiding postoperative VFDs.

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Early postoperative haematomas in neurosurgery

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Acta Neurochir (2016) 158:837–846

A postoperative haematoma can be a very serious complication following a neurosurgical procedure. Patients should be informed about the risks of such an event prior to surgery. From a practical point of view, it would be important to know when the patient is most likely to deteriorate and to require surgery because of a postoperative haematoma and when it might be safe to transfer the patient to the regular ward. The up-to-date studies regarding this topic are few.

Methods We therefore undertook the present retrospective study, including a cohort of all patients operated on at the Department of Neurosurgery in Lund during the years 2011– 2014, with the aim to define the time windows for clinical deterioration and reoperation, and whether risk factors such as anticoagulant agents/antiplatelet therapy, emergency versus elective surgery and abnormal coagulation blood values were present. We also defined the type of surgery resulting in postoperative haematoma and tried to find the clinical state of the patients when they deteriorated, as well as the outcome at 3 months postoperatively.

Results During the time period from June 2011 to November 2014, a total of 7,055 surgical procedures of all kinds were registered at our department. By the search for the diagnosis codes AWE00 and AWD00 (reoperation for deep haemorrhage and for superficial haemorrhage respectively), we identified 93 reoperations, meaning a percentage of 1.3 %. Thirtyfour of the reoperations were done within the first 24 h. Twenty-four patients were reoperated on >24 h but ≤72 h after the first operation. Only four patients who were initially doing well postoperatively showed a delayed clinical deterioration within the time frame from>6 h and ≤24 h postoperatively. This means that 0.06 % of the patients who were operated upon were doing well initially, being completely awake and with no new neurological deficit and no deterioration within the first 6 h postoperatively, and then deteriorated from a postoperative haematoma within the time frame of>6 h and ≤24 h postoperatively.

Conclusions We could conclude that no exact time window distinguished very early from somewhat later postoperative haematomas in our material. However, all but two patients deteriorating between 6 and 24 h after the operation had at least one of the following risk factors defined for postoperative haematoma: meningioma surgery, anticoagulant agents/antiplatelet therapy prior to surgery (including Dalteparin [Fragmin®], Enoxaparinnatrium [Klexane®], Warfarin [Waran®], ASA [Trombyl®] or ASA and caffeine [Treo®]), emergency operation, posterior fossa surgery or chronic subdural haematoma in a patient with a shunt. This material is too small to make any definitive conclusions, but a suggestion could be to include these factors when considering the transfer of a patient from the postoperative intensive care unit to the regular ward.

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New Posterior Atlantoaxial Restricted Non-Fusion Fixation for Atlantoaxial Instability

New Posterior Atlantoaxial Restricted Non-Fusion Fixation for Atlantoaxial Instability

Neurosurgery 78:735–741, 2016

Loss of axial rotation and lateral bending after atlantoaxial fusion reduces a patient’s quality of life. Therefore, effective, nonfusion fixation alternatives are needed for atlantoaxial instability.

OBJECTIVE: To evaluate the initial stability and function of posterior atlantoaxial restricted nonfusion fixation (PAARNF), a new protocol, using cadaveric cervical spines compared with the intact state, destabilization, and posterior C1-C2 rod fixation.

METHODS: Cervical areas C0 through C3 were used from 6 cadaveric spines to test flexion-extension, lateral bending, and axial rotation range of motion (ROM). With the use of a machine, 1.5-Nm torque at a rate of 0.1 Nm/s was used and held for 10 seconds. The specimens were loaded 3 times, and data were collected in the third cycle and tested in the following sequence: (1) intact, (2) destabilization (using a type II odontoid fracture model), (3) destabilization with PAARNF (PAARNF group), and (4) rod implantation (rod group). The order of tests for the PAARNF and rod groups was randomly assigned.

RESULTS: The average flexion-extension ROM in the PAARNF group was 7.44 6 2.05, which was significantly less than in the intact (P = .00) and destabilization (P = .00) groups but not significantly different from that of the rod group (P = .07). The average lateral bending ROM (10.59 6 2.33; P = .00) and axial rotation ROM (38.79 6 13.41; P = .00) of the PAARNF group were significantly greater than in the rod group. However, the values of the PAARNF group showed no significant differences compared with those of the intact group.

CONCLUSION: PAARNF restricted atlantoaxial flexion-extension but preserved axial rotation and lateral bending at the atlantoaxial joint in a type II odontoid fracture model. However, it should not be used clinically until further studies have been performed to test the long-term effects of this procedure.

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A prospective Phase II clinical trial of 5-aminolevulinic acid to assess the correlation of intraoperative fluorescence intensity and degree of histologic cellularity during resection of high-grade gliomas

Combining 5-Aminolevulinic Acid Fluorescence and Intraoperative Magnetic Resonance Imaging in Glioblastoma Surgery

J Neurosurg 124:1300–1309, 2016

There is evidence that 5-aminolevulinic acid (ALA) facilitates greater extent of resection and improves 6-month progression-free survival in patients with high-grade gliomas. But there remains a paucity of studies that have examined whether the intensity of ALA fluorescence correlates with tumor cellularity. Therefore, a Phase II clinical trial was undertaken to examine the correlation of intensity of ALA fluorescence with the degree of tumor cellularity.

Methods A single-center, prospective, single-arm, open-label Phase II clinical trial of ALA fluorescence-guided resection of high-grade gliomas (Grade III and IV) was held over a 43-month period (August 2010 to February 2014). ALA was administered at a dose of 20 mg/kg body weight. Intraoperative biopsies from resection cavities were collected. The biopsies were graded on a 4-point scale (0 to 3) based on ALA fluorescence intensity by the surgeon and independently based on tumor cellularity by a neuropathologist. The primary outcome of interest was the correlation of ALA fluorescence intensity to tumor cellularity. The secondary outcome of interest was ALA adverse events. Sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Spearman correlation coefficients were calculated.

Results A total of 211 biopsies from 59 patients were included. Mean age was 53.3 years and 59.5% were male. The majority of biopsies were glioblastoma (GBM) (79.7%). Slightly more than half (52.5%) of all tumors were recurrent. ALA intensity of 3 correlated with presence of tumor 97.4% (PPV) of the time. However, absence of ALA fluorescence (intensity 0) correlated with the absence of tumor only 37.7% (NPV) of the time. For all tumor types, GBM, Grade III gliomas, and recurrent tumors, ALA intensity 3 correlated strongly with cellularity Grade 3; Spearman correlation coefficients (r) were 0.65, 0.66, 0.65, and 0.62, respectively. The specificity and PPV of ALA intensity 3 correlating with cellularity Grade 3 ranged from 95% to 100% and 86% to 100%, respectively. In biopsies without tumor (cellularity Grade 0), 35.4% still demonstrated ALA fluorescence. Of those biopsies, 90.9% contained abnormal brain tissue, characterized by reactive astrocytes, scattered atypical cells, or inflammation, and 8.1% had normal brain. In nonfluorescent (ALA intensity 0) biopsies, 62.3% had tumor cells present. The ALA-associated complication rate among the study cohort was 3.4%.

Conclusions The PPV of utilizing the most robust ALA fluorescence intensity (lava-like orange) as a predictor of tumor presence is high. However, the NPV of utilizing the absence of fluorescence as an indicator of no tumor is poor. ALA intensity is a strong predictor for degree of tumor cellularity for the most fluorescent areas but less so for lower ALA intensities. Even in the absence of tumor cells, reactive changes may lead to ALA fluorescence.

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Current practice of external ventricular drainage: a survey among neurosurgical departments in Germany

A_Simple_Protocol_to_Prevent_External_Ventricular

Acta Neurochir (2016) 158:847–853

There are various recommendations, but no generally accepted guidelines, to reduce the risk of external ventricular drainage (EVD)-associated infections. The primary objective of the present study was to evaluate the current practice of EVD in a European country and to set the results in perspective to published data.

Method A standardised questionnaire prepared by the Commission of Technical Standards and Norms of the German Society of Neurosurgery was sent to 127 neurosurgical units in Germany.

Results Data were analysed from 99 out of 127 neurosurgical units which had been contacted. Overall, more than 10,000 EVD procedures appear to be performed in Germany annually. There is disagreement about the location where the EVD is inserted, and most EVDs are still inserted in the operation theatre. Most units apply subcutaneous tunnelling. Impregnated EVD catheters are used regularly in only about 20 % of units. Single-shot antibiotic prophylaxis is given in more than half of the units, while continued antibiotic prophylaxis is installed in only 15/99 units at a regular basis. There are discrepancies in the management of prolonged EVD use with regard to replacement policies. Regular cerebrospinal fluid (CSF) sampling is still performed widely. There were no statistical differences in policies with regard to academic versus non-academic units.

Conclusions This survey clearly shows that some newer recommendations drawn from published studies penetrate much slower into clinical routine, such as the use of impregnated catheters, for example. It remains unclear how different policies actually impact quality and outcome in daily routine.

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fMRI activation in the middle frontal gyrus as an indicator of hemispheric dominance for language in brain tumor patients: a comparison with Broca’s area

Functional imaging

Neuroradiology (2016) 58:513–520

Functional MRI (fMRI) can assess language lateralization in brain tumor patients; however, this can be limited if the primary language area—Broca’s area (BA)—is affected by the tumor. We hypothesized that the middle frontal gyrus (MFG) can be used as a clinical indicator of hemispheric dominance for language during presurgical workup.

Methods: Fifty-two right-handed subjects with solitary left hemispheric primary brain tumors were retrospectively studied. Subjects performed a verbal fluency task during fMRI. The MFG was compared to BA for fMRI voxel activation, language laterality index (LI), and the effect of tumor grade on the LI.

Results: Language fMRI (verbal fluency) activated more voxels in MFG than in BA (MFG=315, BA=216, p<0.001). Voxel activations in the left-hemispheric MFG and BA were positively correlated (r = 0.69, p < 0.001). Mean LI in the MFG was comparable to that in BA (MFG = 0.48, BA = 0.39, p = 0.06). LIs in MFG and BA were positively correlated (r = 0.62, p < 0.001). Subjects with high- grade tumors demonstrate lower language lateralization than those with low-grade tumors in both BA and MFG (p = 0.02, p = 0.02, respectively).

Conclusion: MFG is comparable to BA in its ability to indicate hemispheric dominance for language using a measure of verbal fluency and may be an adjunct measure in the clinical determination of language laterality for presurgical planning.

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Predictive factors for decompressive hemicraniectomy in malignant middle cerebral artery infarction

Predictive factors for decompressive hemicraniectomy in malignant middle cerebral artery infarction

Acta Neurochir (2016) 158:865–873

The mortality rate of patients with brain oedema after malignant middle cerebral artery (MCA) infarction approaches 80 % without surgical intervention. Surgical treatment with ipsilateral decompressive hemicraniectomy (DHC) has been shown to dramatically improve survival rates. DHC currently lacks established inclusion criteria and additional research is needed to assess the impact of prognostic factors on functional outcome. The aim of this study was to assess the impact of prognostic factors on functional outcome.

Method A retrospective cohort study was carried out including 46 patients who underwent DHC at the Karolinska University Hospital between 2004 and 2014. The maximum time to surgery was 5 days after symptom debut. The primary endpoint was a dichotomised score on the modified Rankin Scale (mRS) 3 months after surgery, with favourable outcome defined as mRS ≤ 4.

Results When the study population was dichotomised according to the primary endpoint, a significant difference between the groups was seen in preoperative Glasgow Coma Score (GCS), blood glucose levels and the infarction’s involvement of the basal ganglia (p <0.05). In a logistic regression model, preoperative GCS contributed significantly with a 59.6 % increase in the probability of favourable outcome for each point gained in preoperative GCS (p=0.035).

Conclusions The results indicate that preoperative GCS, blood glucose and the infarction’s involvement of the basal ganglia are strong predictors of clinical outcome. These factors should be considered when assessing the probable outcome of DHC, and additional research based on these factors may contribute to improved inclusion criteria for DHC.

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Posterior Cervical Fusion Using Cervical Interfacet Spacers in Patients With Symptomatic Cervical Pseudarthrosis

Posterior Cervical Fusion Using Cervical Interfacet Spacers in Patients With Symptomatic Cervical Pseudarthrosis

Neurosurgery 78:661–668, 2016

Posterior cervical fusion with cervical interfacet spacer (CIS) is a novel allograft technology offering the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion by placing the allograft in compression.

OBJECTIVE: To analyze the clinical and radiological outcomes after posterior cervical fusion with CIS in patients with symptomatic anterior cervical pseudarthroses.

METHODS: Medical records of patients who underwent posterior cervical fusion with CIS for symptomatic pseudarthrosis after anterior cervical diskectomy and fusion were reviewed. Standardized outcome measures such as visual analog scale (VAS) score for neck and arm pain, Neck Disability Index (NDI), and upright lateral cervical radiographs were reviewed.

RESULTS: There were 19 patients with symptomatic cervical pseudarthrosis. Preoperative symptoms included refractory neck or arm pain. The average follow-up was 20 months (range, 12-56 months). There was improvement in VAS score for neck pain (P < .004), radicular arm pain (P < .007), and NDI score (P < .06) after surgery, with 83%, 72%, and 67% of patients showing improvement in their VAS neck pain, VAS arm pain, and NDI scores, respectively. Fusion rate was high, with fusion occurring at all levels treated for pseudarthrosis. There was a small improvement in cervical lordosis (mean difference, 2 6 5.17; P = .09) and slight worsening of C2-7 sagittal vertical axis after surgery (mean difference, 1.89 6 7.87 mm; P = .43).

CONCLUSION: CIS provides an important fusion technique, allowing placement of an allograft in compression for posterior cervical fusion in patients with anterior cervical pseudarthroses. Although there was improvement in clinical outcome measures after surgery, placement of CIS had no clinically significant impact on cervical lordosis and C2-7 sagittal vertical axis.

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Cost analysis of awake versus asleep deep brain stimulation

iCT-DBS

J Neurosurg 124:1517–1523, 2016

The objective of this study was to compare the cost of deep brain stimulation (DBS) performed awake versus asleep at a single US academic health center and to compare costs across the University HealthSystem Consortium (UHC) Clinical Database.

Methods Inpatient and outpatient demographic and hospital financial data for patients receiving a neurostimulator lead implant (from the first quarter of 2009 to the second quarter of 2014) were collected and analyzed. Inpatient charges included those associated with International Classification of Diseases, Ninth Revision (ICD-9) procedure code 0293 (implantation or replacement of intracranial neurostimulator lead). Outpatient charges included all preoperative charges ≤ 30 days prior to implant and all postoperative charges ≤ 30 days after implant. The cost of care based on reported charges and a cost-to-charge ratio was estimated. The UHC database was queried (January 2011 to March 2014) with the same ICD-9 code. Procedure cost data across like hospitals (27 UHC hospitals) conducting similar DBS procedures were compared.

Results Two hundred eleven DBS procedures (53 awake and 158 asleep) were performed at a single US academic health center during the study period. The average patient age (± SD) was 65 ± 9 years old and 39% of patients were female. The most common primary diagnosis was Parkinson’s disease (61.1%) followed by essential and other forms of tremor (36%). Overall average DBS procedure cost was $39,152 ± $5340. Asleep DBS cost $38,850 ± $4830, which was not significantly different than the awake DBS cost of $40,052 ± $6604. The standard deviation for asleep DBS was significantly lower (p ≤ 0.05). In 2013, the median cost for a neurostimulator implant lead was $34,052 at UHC-affiliated hospitals that performed at least 5 procedures a year. At Oregon Health & Science University, the median cost was $17,150 and the observed single academic health center cost for a neurostimulator lead implant was less than the expected cost (ratio 0.97).

Conclusions In this single academic medical center cost analysis, DBS performed asleep was associated with a lower cost variation relative to the awake procedure. Furthermore, costs compared favorably to UHC-affiliated hospitals. While asleep DBS is not yet standard practice, this center exclusively performs asleep DBS at a lower cost than comparable institutions.

 

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Microendoscopic discectomy versus open discectomy for lumbar disc herniation: a meta-analysis

Complications of endoscopic microdiscectomy using the EASYGO! system

Eur Spine J (2016) 25:1373–1381

Purpose: To compare the outcomes of microendoscopic discectomy and open discectomy for patients with lumbar disc herniation.

Methods: An extensive search of studies was performed in PubMed, Medline, Embase, Cochrane library and Google Scholar. The following outcome measures were extracted: visual analogue scale (VAS), Oswestry disability index (ODI), complication, operation time, blood loss and length of hospital stay. Data analysis was conducted with RevMan 5.0.

Results: Five randomized controlled trials involving 501 patients were included in this meta-analysis. The pooled analysis showed that there was no significant difference in the VAS, ODI or complication between the two groups. However, compared with the open discectomy, the microendoscopic discectomy was associated with less blood loss [WMD = -151.01 (-288.22, -13.80), P = 0.03], shorter length of hospital stay [WMD = -69.33 (-110.39, -28.28), P = 0.0009], and longer operation time [WMD = 18.80 (7.83, 29.76), P = 0.0008].

Conclusions: Microendoscopic discectomy, which requires a demanding learning curve, may be a safe and effective alternative to conventional open discectomy for patients with lumbar disc herniation.

 

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Clinical experience with navigated 3D ultrasound angiography (power Doppler) in microsurgical treatment of brain arteriovenous malformations

Clinical experience with navigated 3D ultrasound angiography (power Doppler) in microsurgical treatment of brain arteriovenous malformations

Acta Neurochir (2016) 158:875–883

We have previously described a method that has the potential to improve surgery of arteriovenous malformations (AVMs). In the present paper, we present our clinical results.

Materials and methods Of 78 patients referred for AVMs to our University Hospital from our geographical catchment region from 2005 through 2013, 31 patients were operated on with microsurgical technique. 3D MR angiography (MRA) with neuronavigation was used for planning. Navigated 3D ultrasound angiography (USA) was used to identify and clip feeders in the initial phase of the operation. None of our patients was embolized preoperatively as part of the surgical procedure. The niduses were extirpated based on the 3D USA. After extirpation, controls were done with 3D USA to verify that the AVMs were completely removed. The Spetzler three-tier classification of the patients was: A: 21, B: 6, C: 4.

Results Sixty-eight feeders were identified on preoperative MRA and DSA and 67 feeders were identified and clipped by guidance of intraoperative 3D USA. Six feeders identified preoperatively were missed by 3D USA, while five preoperatively unknown feeders were found and clipped. The overall average bleeding was 440 ml. There was a significant reduction in average bleeding in the last 15 operations compared to the first 16 (340 vs. 559 ml, p = 0.019). We had no serious morbidity (GOS 3 or less). New deficits due to surgery were two patients with quadrantanopia (one class B and one class C), the latter (C) also acquired epilepsy. One patient (class A) acquired a hardly noticeable paresis in two fingers. One hundred percent angiographic cure was achieved in all patients, as evaluated by postoperative DSA.

Conclusions Navigated intraoperative 3D USA is a useful tool to identify and clip AVM feeders. Microsurgical extirpation assisted by navigated 3D USA is an effective and safe method for removing AVMs.

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Surgical Decompression of Arachnoid Cysts Leads to Improved Quality of Life

Suprasellar Arachnoid Cysts- Toward a New Simple Classification Based on Prognosis and Treatment Modality

Neurosurgery 78:613–625, 2016

There is no previous prospective study on the outcome of surgical decompression of intracranial arachnoid cysts (AC).

OBJECTIVE: To investigate if surgical fenestration for AC leads to change in patients’ health-related quality of life.

METHODS: Prospective study including 76 adult patients operated for AC. Patients responded to Short Form-36 and Glasgow Benefit Inventory quality of life questionnaires, and to visual analogue scales, assessing headache and dizziness pre- and postoperatively. Patient scores were compared with those of a large sample of healthy individuals.

RESULTS: Preoperatively, 84.2% of the patients experienced headache and 70.1% dizziness. Mean pre- versus postoperative Visual Analogue Scale scores for headache and dizziness dropped from 45.6 to 25.7 and from 35.2 to 12.2, respectively. Preoperative Short Form-36 scores were significantly below age norms in all subscales, but improved after surgery into normal range in 7 out of 8 subscales for middle-aged and older patients. Younger patients’ scores remained lower than age norm in 6 out of 8 subscales. A significant postoperative improvement was seen in 3 out of 4 Glasgow Benefit Inventory subscales. Improvement in headache and/or dizziness, but not preoperative cyst size or reduction in cyst volume, correlated with improvement in 6 out of 8 Short Form-36 subscales and 3 out of 4 Glasgow Benefit Inventory subscales. Only 1 patient experienced a severe complication causing permanent invalidity.

CONCLUSION: Surgery for AC can be performed with a fairly low risk of complications and yields significant improvement in quality of life correlated to postoperative improvement in headache and dizziness. These findings may justify a more liberal approach to surgical treatment for AC.

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ALIF and total disc replacement versus 2-level circumferential fusion with TLIF: a prospective, randomized, clinical and radiological trial

ALIF-TDR vs TLIF

Eur Spine J (2016) 25:1558–1566

Study design: Prospective, randomized trial.

Purpose: The treatment of degenerative disc disease (DDD) with two-level fusion has been associated with a reasonable rate of complications. The aim of the present study was to compare (Hybrid) stand-alone anterior lumbar interbody fusion (ALIF) at L5/S1 with total disc replacement at L4/5 (TDR) as an alternative surgical strategy to (Fusion) 2-level circumferential fusion employing trans- foraminal lumbar interbody fusion (TLIF) with transpedicular stabilization at L4–S1.

Methods: A total of 62 patients with symptomatic DDD of segments L5/S1 (Modic ≥2°) and L4/5 (Modic ≤2°; positive discography) were enrolled; 31 were treated with Hybrid and 31 with Fusion. Preoperatively, at 0, 12, and a mean follow-up of 37 months, clinical (ODI, VAS) and radiological evaluations (plain/extension-flexion radiographs evaluated for implant failure, fusion, global and segmental lordosis, and ROM) were performed.

Results: In 26 of 31 Hybrid and 24 of 31 Fusion patients available at the final follow-up, we found a significant clinical improvement compared to preoperatively. Hybrid patients had significantly lower VAS scores immediately postoperatively and at follow-up compared to Fusion patients. The complication rates were low and similar between the groups. Lumbar lordosis increased in both groups. The increase was mainly located at L4–S1 in the Hybrid group and at L1–L4 in the Fusion group. Hybrid patients presented with increased ROM at L4/5 and L3/4, and Fusion patients presented with increased ROM at L3/4, with significantly greater ROM at L3/4 compared to Hybrid patients at follow-up.

Conclusions Hybrid surgery is a viable surgical alternative for the presented indication. Approach-related inferior trauma and the balanced restoration of lumbar lordosis resulted in superior clinical outcomes compared to two-level circumferential fusion with TLIF.

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Effect of weekend admission on in-hospital mortality and functional outcomes for patients with acute subarachnoid haemorrhage (SAH)

A Simple and Quantitative Method to Predict Symptomatic Vasospasm After Subarachnoid Hemorrhage Based on Computed Tomography- Beyond the Fisher Scale

Acta Neurochir (2016) 158:829–835

Aneurysmal subarachnoid haemorrhage (aSAH) is an acute cerebrovascular event with high socioeconomic impact as it tends to affect younger patients. The recent NCEPOD study looking into management of aSAH has recommended that neurovascular units in the United Kingdom should aim to secure cerebral aneurysms within 48 h and that delays because of weekend admissions can increase the mortality and morbidity attributed to aSAH.

Method We used data from a prospective audit of aSAH patients admitted between January 2009 and December 2011. The baseline demographic and clinical features of the weekend and weekday groups were compared using the chisquared test and T-test. Cox proportional hazards models (Proc Phreg in SAS) were used to calculate the adjusted overall hazard of in-hospital death associated with admission on weekend, adjusting for age, sex, baseline WFNS grade, type of treatment received and time from scan to treatment. Sliding dichotomy analysis was used to estimate the difference in outcomes after SAH at 3 months in weekend and weekday admissions.

Results Those admitted on weekends had a significantly higher scan to treatment time (83.05 ± 83.4 h vs 40.4 ± 53.4 h, P < 0.0001) and admission to treatment (71.59 ± 79.8 h vs 27.5 ± 44.3 h, P<0.0001) time. After adjustments for adjusted for relevant covariates weekend admission was statistically significantly associated with excess in-hospital mortality (HR= 2.1, CL [1.13–4.0], P=0.01). After adjustments for all the baseline covariates, the sliding dichotomy analysis did not show effects of weekend admission on long-term outcomes on the good, intermediate and worst prognostic bands.

Conclusions: This study provides important data showing excess in-hospital mortality of patients with SAH on weekend admissions served by the United Kingdom’s National Health Service. However, there were no effects of weekend admission on long-term outcomes.

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Complication-Effectiveness Analysis for Unruptured Intracranial Aneurysm Surgery

Aneurysm surgery

Neurosurgery 78:648–659, 2016

The aim of intervention for unruptured intracranial aneurysms (UIAs) is safe, effective treatment.

OBJECTIVE: To analyze a prospective database for variables influencing the risk of surgery to produce a risk model adjusting this risk for effectively treated aneurysms.

METHODS: First, we identified variables to create a model from multiple logistic regression for complications of surgery leading to a 12-month modified Rankin Scale score .1. Second, we established the long-term cumulative incidence of freedom from retreatment or rupture (treated aneurysm) from Kaplan-Meier analysis. Third, we combined these analyses to establish a model of risk of surgery per effective treatment.

RESULTS: One thousand twelve patients with 1440 UIA underwent 1080 craniotomies. We found that 10.1% (95% confidence interval [CI], 8.4-12.0) of craniotomies resulted in a complication leading to a modified Rankin Scale score .1 at 12 months. Logistic regression found age (odds ratio, 1.04; 95% CI, 1.02-1.06), size (odds ratio, 1.12; 95% CI, 1.09-1.15), and posterior circulation location (odds ratio, 2.95; 95% CI, 1.82-4.78) to be significant. Cumulative 10-year risk of retreatment or rupture was 3.0% (95% CI, 1.3-7.0). The complication-effectiveness model was derived by dividing the complication risk by the 10-year cumulative freedom from retreatment or rupture proportion. Risk per effective treatment ranged from 1% for a 5-mm anterior circulation UIA in a 20-year-old patient to 70% for a giant posterior circulation UIA in a 70-year-old patient.

CONCLUSION: Complication-effectiveness analyses increase the information available with regard to outcome for the management of UIAs.

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Clinical management of pineal cysts: a worldwide online survey

Prevalence and natural history of pineal cysts in adults

Acta Neurochir (2016) 158:663–669

A pineal cyst is a benign affection of a pineal gland on the borderline between a pathological lesion and a variant of normality. Clinical management of patients with a pineal cyst remains controversial, especially when patients present with non-specific symptoms.

Methods An online questionnaire consisting of 13 questions was completed by 110 neurosurgeons worldwide. Responses were entered into a database and subsequently analysed.

Results Based on data from the questionnaire, the main indication criteria for pineal cyst resection are hydrocephalus (90 % of the respondents), Parinaud’s syndrome (80 %) and growth of the cyst (68 %). Only 15 % of the respondents occasionally operate on patients with non-specific symptoms. If surgery is indicated, improvement is expected in 88 % of the patients. The vast majority of the respondents favour a supracerebellar infratentorial approach to the pineal region. Most (78 %) of the respondents regarded the patient registry as a potentially useful instrument.

Conclusions This survey sheds light on the current practice of pineal cyst management across the world. Most of the respondents perform surgery on pineal cysts only if patients are presenting with symptoms attributable to a mass effect. Surgery for patients with non-specific complaints (headache, vertigo) is not widely accepted, although it may prove effective. A prospective patient registry might be useful in the decisionmaking process in the clinical management of pineal cysts.

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Neurosurgical treatment of glossopharyngeal neuralgia: analysis of 103 cases

GP neuralgia

J Neurosurg 124:1088–1092, 2016

The object of this study was to investigate the immediate and long-term follow-up results of glossopharyngeal nerve rhizotomy (GPNR) with or without partial vagus nerve rhizotomy (VNR) for treating glossopharyngeal neuralgia (GPN).

Methods A retrospective review of the case notes of patients who had undergone surgery for GPN in the authors’ department between 2008 and 2013 was performed to investigate baseline characteristics and immediate outcomes during the hospitalization. For the long-term results, a telephone survey was performed, and information on pain recurrence and permanent complications was collected. Pain relief meant no pain or medication, any pain persisting after surgery was considered to be treatment failure, and any pain returning during the follow-up period was considered to be pain recurrence. For comparative study, the patients were divided into 2 cohorts, that is, patients treated with GPNR alone and those treated with GPNR+VNR.

Results One hundred three procedures, consisting of GPNR alone in 38 cases and GPNR+VNR in 65 cases, were performed in 103 consecutive patients with GPN. Seventy-nine of the 103 patients could be contacted for the follow-up study, with a mean follow-up duration of 2.73 years (range 1 month–5.75 years). While there were similar results (GPNR vs GPNR+VNR) in immediate pain relief rates (94.7% vs 93.8%), immediate complication rates (7.9% vs 4.6%), and longterm pain relief rates (92.3% vs 94.3%) between the 2 cohorts, a great difference was seen in long-term complications (3.8% vs 35.8%). The long-term complication rate for the combined GPNR+VNR cohort was 9.4 times higher than that in the GPNR cohort. There was no operative or perioperative mortality. Immediate complications occurred in 6 cases, consisting of poor wound healing in 3 cases, and CSF leakage, hoarseness, and dystaxia in 1 case each. Permanent complications occurred in 20 patients (25.3%) and included cough while drinking in 10 patients, pharyngeal discomfort in 8 patients, and hoarseness and dysphagia in 1 case each.

Conclusions In general, this study indicates that GPNR alone or in combination with VNR is a safe, simple, and effective treatment option for GPN. It may be especially valuable for patients who are not suitable for the microvascular decompression (MVD) procedure and for surgeons who have little experience with MVD. Of note, this study renews the significance of GPNR alone, which, the authors believe, is at least valuable for a subgroup of GPN patients, with significantly fewer long-term complications than those for rhizotomy for both glossopharyngeal nerve and rootlets of the vagus nerve.

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Analysis of superiorly projecting anterior communicating artery aneurysms

Analysis of superiorly projecting anterior communicating artery aneurysms

Neurosurg Rev (2016) 39:225–235

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics.

We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome.

This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005–2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types.

There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83 %. Type 1 presented more often with SAH (95.5 %, p=0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5 % p=0.0016), and there was higher rate of intraoperative rupture (37.5 %). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50 %).

The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.

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Cerebellar and hindbrain motion in Chiari malformation with and without syringomyelia

Cerebellar and hindbrain motion in Chiari malformation with and without syringomyelia

J Neurosurg Spine 24:546–555, 2016

The pathogenesis of syringomyelia associated with Chiari malformation type I (CM-I) is unclear. Theories of pathogenesis suggest the cerebellar tonsils may obstruct CSF flow or alter pressure gradients, or their motion might act as a piston to increase CSF pressure in the spinal subarachnoid space. This study was performed to measure cerebellar tonsillar and hindbrain motion in CM-I and assess the potential contributions to syrinx formation.

Methods Sixty-four CM-I patients and 25 controls were retrospectively selected from a clinical database, and all subjects had undergone cardiac-gated cine balanced fast-field echo MRI. There were a total of 36 preoperative CM-I scans, which consisted of 15 patients with and 21 patients without syringomyelia. Nineteen patients underwent paired pre- and postoperative imaging. Anteroposterior (AP) and superoinferior (SI) movements of the tip of the cerebellar tonsils, obex, fastigium of the fourth ventricle, pontomedullary junction, and cervicomedullary junction were measured. The distance between the fastigium and tip of the tonsils was used to calculate tonsillar tissue strain.

Results CM-I patients had significantly greater cerebellar tonsillar motion in both the AP and SI directions than controls (AP +0.34 mm [+136%], p < 0.001; SI +0.49 mm [+163%], p < 0.001). This motion decreased after posterior fossa decompression (AP -0.20 mm [-33%], p = 0.001; SI -0.29 mm [-36%]; p < 0.001), but remained elevated above control levels (AP +56%, p = 0.021; SI +67%, p = 0.015). Similar trends were seen for all other tracked landmarks. There were no significant differences in the magnitude or timing of motion throughout the hindbrain between CM-I patients with and without syringomyelia. Increased tonsillar tissue strain correlated with Valsalva headaches (p = 0.03).

Conclusions Cerebellar tonsillar motion may be a potential marker of CM-I and may have use in tailoring surgical procedures. The lack of association with syringomyelia suggests that tonsillar motion alone is not the driver of syrinx formation. Tonsillar tissue strain may play a part in the pathophysiology of Valsalva headaches.

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