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Step-wise pterional combined epidural and subdural approach to clip large carotid-ophthalmic segment aneurysms

Acta Neurochirurgica (2019) 161:607–610

Microsurgical clipping of large ophthalmic-carotid artery (OA) aneurysms is technically challenging. Among the reported approaches, pterional combined epidural and subdural approach is one of the efficient choices.

Method We have applied this approach to treat a 33-year old female patient with a left large OA aneurysm. The step-wise technical details of this approach are reported.

Conclusion We show that it is a safe way to clip large OA aneurysms through a step-wise pterional combined epidural and subdural approach, which could make a clear anatomy and a confident manipulation.

 

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The transcortical equatorial approach for gliomas of the mesial temporal lobe

J Neurosurg 130:822–830, 2019

Many surgical approaches have been described for lesions within the mesial temporal lobe (MTL), but there are limited reports on the transcortical approach for the resection of tumors within this region. Here, the authors describe the technical considerations and functional outcomes in patients undergoing transcortical resection of gliomas of the MTL.

METHODS Patients with a glioma (WHO grades I–IV) located within the MTL who had undergone the transcortical approach in the period between 1998 and 2016 were identified through the University of California, San Francisco (UCSF) tumor registry and were classified according to tumor location: preuncus, uncus, hippocampus/parahippocampus, and various combinations of the former groups. Patient and tumor characteristics and outcomes were determined from operative, radiology, pathology, and other clinical reports that were available through the UCSF electronic medical record.

RESULTS Fifty patients with low- or high-grade glioma were identified. The mean patient age was 46.8 years, and the mean follow-up was 3 years. Seizures were the presenting symptom in 82% of cases. Schramm types A, C, and D represented 34%, 28%, and 38% of the tumors, and the majority of lesions were located at least in part within the hippocampus/ parahippocampus. For preuncus and preuncus/uncus tumors, a transcortical approach through the temporal pole allowed for resection. For most tumors of the uncus and those extending into the hippocampus/parahippocampus, a corticectomy was performed within the middle and/or inferior temporal gyri to approach the lesion. To locate the safest corridor for the corticectomy, language mapping was performed in 96.9% of the left-sided tumor cases, and subcortical motor mapping was performed in 52% of all cases. The mean volumetric extent of resection of low- and high-grade tumors was 89.5% and 96.0%, respectively, and did not differ by tumor location or Schramm type. By 3 months’ followup, 12 patients (24%) had residual deficits, most of which were visual field deficits. Three patients with left-sided tumors (9.4% of dominant-cortex lesions) experienced word-finding difficulty at 3 months after resection, but 2 of these patients demonstrated complete resolution of symptoms by 1 year.

CONCLUSIONS Mesial temporal lobe gliomas, including larger Schramm type C and D tumors, can be safely and aggressively resected via a transcortical equatorial approach when used in conjunction with cortical and subcortical mapping.

 

 

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Delayed hearing loss after microvascular decompression for hemifacial spasm

Acta Neurochirurgica (2019) 161:503–508

This study aimed to analyze cases of delayed hearing loss after microvascular decompression (MVD) for hemifacial spasm and identify the characteristic features of these patients.

Methods We retrospectively reviewed the medical records of 3462 patients who underwent MVD for hemifacial spasm between January 1998 and August 2017.

Results Among these, there were 5 cases in which hearing was normal immediately postoperatively but delayed hearing loss occurred. None of the 5 patients reported any hearing disturbance immediately after the operation. However, they developed hearing problems suddenly after some time (median, 22 days; range 10–45 days). On examination, sensorineural hearing loss was confirmed. High-dose corticosteroid treatment was prescribed. Preoperative hearing levels were restored after several months (median duration from the time of the operation, 45 days; range 22–118 days). Interestingly, the inter-peak latency of waves I–III in the brainstem auditory evoked potential (BAEP) was prolonged during the surgery, but recovered within a short time.

Conclusion Delayed hearing loss may occur after MVD for HFS. Prolongation of the inter-peak latency of waves I–III seems to be associated with the occurrence of delayed hearing loss. It is possible that BAEP changes may predict delayed hearing loss, but confirmatory evidence is not available as yet. Analysis of more cases is necessary to determine the utility of BAEP monitoring to predict delayed hearing loss after MVD and to identify its exact cause.

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Surgical management of spinal meningiomas

J Neurosurg Spine 30:308–313, 2019

Spinal meningiomas (sMNGs) are relatively rare in comparison to intracranial MNGs. sMNGs localized anterior to the denticulate ligament (aMNGs) represent a surgically challenging subgroup. A high perioperative complication rate due to the need for complex surgical approaches has been described. In the present study, the authors report on their surgical experience that involves two institutions in which 207 patients underwent surgery for sMNGs. Special focus was placed on patients with aMNGs that were treated via a unilateral posterior approach (ULPA).

METHODS Between 2005 and 2017, 207 patients underwent resection of sMNGs at one of two institutions. The following characteristics were assessed: tumor size and localization, surgical approach, duration of surgery, grade of resection, peri- and postoperative complication rates, and neurological outcome. Data were compared between the subgroups of patients according to the lesion’s relationship to the denticulate ligament and to surgical approach.

RESULTS The authors identified 48 patients with aMNGs, 86 patients with lateral MNGs, and 76 patients with posterior MNGs (pMNGs). Overall, 66.6% of aMNGs and 64% of pMNGs were reached via a ULPA. aMNGs that were approached via a ULPA showed reduced duration of surgery (131 vs 224 minutes, p < 0.0001) and had surgical complication rates and neurological outcomes comparable to those of lesions that were approached via a bilateral approach. No significant differences in complication rate, outcomes, and extent of resection were seen between aMNGs and pMNGs.

CONCLUSIONS The duration of surgery, extent of resection, and outcomes are comparable between aMNGs and pMNGs when removed via a ULPA. Thus, ULPA represents a safe route to achieve a gross-total resection, even in cases of aMNG.

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The role of diffusion tensor imaging in the diagnosis, prognosis, and assessment of recovery and treatment of spinal cord injury: a systematic review

Neurosurg Focus 46 (3):E7, 2019

Diffusion tensor imaging (DTI) is an MRI tool that provides an objective, noninvasive, in vivo assessment of spinal cord injury (SCI). DTI is significantly better at visualizing microstructures than standard MRI sequences. In this imaging modality, the direction and amplitude of the diffusion of water molecules inside tissues is measured, and this diffusion can be measured using a variety of parameters. As a result, the potential clinical application of DTI has been studied in several spinal cord pathologies, including SCI. The aim of this study was to describe the current state of the potential clinical utility of DTI in patients with SCI and the challenges to its use as a tool in clinical practice.

METHODS A search in the PubMed database was conducted for articles relating to the use of DTI in SCI. The citations of relevant articles were also searched for additional articles.

RESULTS Among the most common DTI metrics are fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. Changes in these metrics reflect changes in tissue integrity. Several DTI metrics and combinations thereof have demonstrated significant correlations with clinical function both in model species and in humans. Its applications encompass the full spectrum of the clinical assessment of SCI including diagnosis, prognosis, recovery, and efficacy of treatments in both the spinal cord and potentially the brain.

CONCLUSIONS DTI and its metrics have great potential to become a powerful clinical tool in SCI. However, the current limitations of DTI preclude its use beyond research and into clinical practice. Further studies are needed to significantly improve and resolve these limitations as well as to determine reliable time-specific changes in multiple DTI metrics for this tool to be used accurately and reliably in the clinical setting.

 

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The Patient-Reported Outcomes Measurement Information System in spine surgery: a systematic review

J Neurosurg Spine 30:405–413, 2019

The Patient-Reported Outcomes Measurement Information System (PROMIS) was developed to provide a standardized measure of clinical outcomes that is valid and reliable across a variety of patient populations. PROMIS has exhibited strong correlations with many legacy patient-reported outcome (PRO) measures. However, it is unclear to what extent PROMIS has been used within the spine literature. In this context, the purpose of this systematic review was to provide a comprehensive overview of the PROMIS literature for spine-specific populations that can be used to inform clinicians and guide future work. Specifically, the authors aimed to 1) evaluate publication trends of PROMIS in the spine literature, 2) assess how studies have used PROMIS, and 3) determine the correlations of PROMIS domains with legacy PROs as reported for spine populations.

METHODS Studies reporting PROMIS scores among spine populations were identified from PubMed/MEDLINE and a review of reference lists from obtained studies. Articles were excluded if they did not report original results, or if the study population was not evaluated or treated for spine-related complaints. Characteristics of each study and journal in which it was published were recorded. Correlation of PROMIS to legacy PROs was reported with 0.1 ≤ |r| < 0.3, 0.3 ≤ |r| < 0.5, and |r| ≥ 0.5 indicating weak, moderate, and strong correlations, respectively.

RESULTS Twenty-one articles were included in this analysis. Twelve studies assessed the validity of PROMIS whereas 9 used PROMIS as an outcome measure. The first study discussing PROMIS in patients with spine disorders was published in 2012, whereas the majority were published in 2017. The most common PROMIS domain used was Pain Interference. Assessments of PROMIS validity were most frequently performed with the Neck Disability Index. PROMIS domains demonstrated moderate to strong correlations with the legacy PROs that were evaluated. Studies assessing the validity of PROMIS exhibited substantial variability in PROMIS domains and legacy PROs used for comparisons.

CONCLUSIONS There has been a recent increase in the use of PROMIS within the spine literature. However, only a minority of studies have incorporated PROMIS for its intended use as an outcomes measure. Overall, PROMIS has exhibited moderate to strong correlations with a majority of legacy PROs used in the spine literature. These results suggest that PROMIS can be effective in the assessment and tracking of PROs among spine populations.

 

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Defining the lateral limits of the endoscopic endonasal transtuberculum transplanum approach: anatomical study with pertinent quantitative analysis

Journal of Neurosurgery JNS, 130(3), 848-860

The extended endoscopic endonasal transtuberculum transplanum approach is currently used for the surgical treatment of selected midline anterior skull base lesions. Nevertheless, the possibility of accessing the lateral aspects of the planum sphenoidale could represent a limitation for such an approach. To the authors’ knowledge, a clear definition of the eventual anatomical boundaries has not been delineated. Hence, the present study aimed to detail and quantify the maximum amount of bone removal over the planum sphenoidale required via the endonasal pathway to achieve the most lateral extension of such a corridor and to evaluate the relative surgical freedom.

METHODS
Six human cadaveric heads were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The laboratory rehearsals were run as follows: 1) preliminary predissection CT scans, 2) the endoscopic endonasal transtuberculum transplanum approach (lateral limit: medial optocarotid recess) followed by postdissection CT scans, 3) maximum lateral extension of the transtuberculum transplanum approach followed by postdissection CT scans, and 4) bone removal and surgical freedom analysis (a nonpaired Student t-test). A conventional subfrontal bilateral approach was used to evaluate, from above, the bone removal from the planum sphenoidale and the lateral limit of the endonasal route.

RESULTS
The endoscopic endonasal transtuberculum transplanum approach was extended at its maximum lateral aspect in the lateral portion of the anterior skull base, removing the bone above the optic prominence, that is, the medial portion of the lesser sphenoid wing, including the anterior clinoid process. As expected, a greater bone removal volume was obtained compared with the approach when bone removal is limited to the medial optocarotid recess (average 533.45 vs 296.07 mm2; p < 0.01). The anteroposterior diameter was an average of 8.1 vs 15.78 mm, and the laterolateral diameter was an average of 18.77 vs 44.54 mm (p < 0.01). The neurovascular contents of this area were exposed up to the insular segment of the middle cerebral artery. The surgical freedom analysis revealed a possible increased lateral maneuverability of instruments inserted in the contralateral nostril compared with a midline target (average 384.11 vs 235.31 mm2; p < 0.05).

CONCLUSIONS
Bone removal from the medial aspect of the lesser sphenoid wing, including the anterior clinoid process, may increase the exposure and surgical freedom of the extended endoscopic endonasal transtuberculum transplanum approach over the lateral segment of the anterior skull base. Although this study represents a preliminary anatomical investigation, it could be useful to refine the indications and limitations of the endoscopic endonasal corridor for the surgical management of skull base lesions involving the lateral portion of the planum sphenoidale.

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Artificial disc replacement versus fusion in patients with cervical degenerative disc disease and radiculopathy: a randomized controlled trial with 5-year outcomes

J Neurosurg Spine 30:323–331, 2019

The method of artificial disc replacement (ADR) has been developed as an alternative treatment to fusion surgery after decompression for cervical degenerative disc disease (DDD) with radiculopathy. Preserving the motion of ADR devices aims to prevent immobilization side effects such as adjacent-segment pathology (ASP). However, longterm follow-up evaluations using MRI are needed to investigate if this intent is achieved.

METHODS The authors performed a randomized controlled trial with 153 patients (mean age 47 years) undergoing surgery for cervical radiculopathy. Eighty-three patients received an ADR and 70 patients underwent fusion surgery. Outcomes after 5 years were assessed using patient-reported outcome measures using the Neck Disability Index (NDI) score as the primary outcome; motion preservation and heterotopic ossification by radiography; ASP by MRI; and secondary surgical procedures.

RESULTS Scores on the NDI were approximately halved in both groups: the mean score after 5 years was 36 (95% confidence interval [CI] 31–41) in the ADR group and 32 (95% CI 27–38) in the fusion group (p = 0.48). There were no other significant differences between the groups in six other patient-related outcome measures. Fifty-four percent of the patients in the ADR group preserved motion at the operated cervical level and 25% of the ADRs were spontaneously fused. Seventeen ADR patients (21%) and 7 fusion patients (10%) underwent secondary surgery (p = 0.11), with 5 patients in each group due to clinical ASP.

CONCLUSIONS In patients with cervical DDD and radiculopathy decompression as well as ADR, surgery did not result in better clinical or radiological outcomes after 5 years compared with decompression and fusion surgery.

Clinical trial registration no.: 44347115 (ISRCTN).

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Microsurgical anatomy of the subthalamic nucleus: correlating fiber dissection results with 3-T magnetic resonance imaging using neuronavigation

J Neurosurg 130 (3): 716-732

Despite the extensive use of the subthalamic nucleus (STN) as a deep brain stimulation (DBS) target, unveiling the extensive functional connectivity of the nucleus, relating its structural connectivity to the stimulation-induced adverse effects, and thus optimizing the STN targeting still remain challenging. Mastering the 3D anatomy of the STN region should be the fundamental goal to achieve ideal surgical results, due to the deep-seated and obscure position of the nucleus, variable shape and relatively small size, oblique orientation, and extensive structural connectivity. In the present study, the authors aimed to delineate the 3D anatomy of the STN and unveil the complex relationship between the anatomical structures within the STN region using fiber dissection technique, 3D reconstructions of high-resolution MRI, and fiber tracking using diffusion tractography utilizing a generalized q-sampling imaging (GQI) model.

METHODS
Fiber dissection was performed in 20 hemispheres and 3 cadaveric heads using the Klingler method. Fiber dissections of the brain were performed from all orientations in a stepwise manner to reveal the 3D anatomy of the STN. In addition, 3 brains were cut into 5-mm coronal, axial, and sagittal slices to show the sectional anatomy. GQI data were also used to elucidate the connections among hubs within the STN region.

RESULTS
The study correlated the results of STN fiber dissection with those of 3D MRI reconstruction and tractography using neuronavigation. A 3D terrain model of the subthalamic area encircling the STN was built to clarify its anatomical relations with the putamen, globus pallidus internus, globus pallidus externus, internal capsule, caudate nucleus laterally, substantia nigra inferiorly, zona incerta superiorly, and red nucleus medially. The authors also describe the relationship of the medial lemniscus, oculomotor nerve fibers, and the medial forebrain bundle with the STN using tractography with a 3D STN model.

CONCLUSIONS
This study examines the complex 3D anatomy of the STN and peri-subthalamic area. In comparison with previous clinical data on STN targeting, the results of this study promise further understanding of the structural connections of the STN, the exact location of the fiber compositions within the region, and clinical applications such as stimulation-induced adverse effects during DBS targeting.

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Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for the Treatment of Adults With Metastatic Brain Tumors: Executive Summary

Neurosurgery 84:550–552, 2019

The Congress of Neurological Surgeons systematic review and evidencebased clinical practice parameter guidelines for the treatment of adults with metastatic brain tumorswas first published in 2010. Because of the time elapsed since that publication, an update of this set of guidelines based on literature published since is now indicated.

OBJECTIVE: To establish the best evidence-based management of metastatic brain tumors over all commonly used diagnostic and treatment modalities in regularly encountered clinical situations.

METHODS: Literature searches regarding management of metastatic brain tumors with whole brain radiation therapy, surgery, stereotactic radiosurgery, chemotherapy, prophylactic anticonvulsants, steroids, instances of multiple brain metastases, and emerging and investigational therapies were carried out to answer questions designed by consensus of a multidisciplinary writing group.

RESULTS: Recommendations were created and their strength linked to the quality of the literature data available thus creating an evidence-based guideline. Importantly, shortcomings and biases to the literature data are brought out so as to provide guidance for future investigation and improvements in the management of patients with metastatic brain tumors.

CONCLUSION: This series of guidelines was constructed to assess the most current and clinically relevant evidence for management of metastatic brain tumors. They set a benchmark regarding the current evidence base for this management while also highlighting important key areas for future basic and clinical research, particularly on those topics for which no recommendations could be formulated.

The full guideline can be found here.

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Anterior Reduction and Fusion of Cervical Facet Dislocations

Neurosurgery 84:388–395, 2019

Cervical facet dislocations are among the most common traumatic spinal injuries. Posterior, anterior, and combined surgical approaches have been described and are widely debated.

OBJECTIVE: To demonstrate efficacy in anterior-only surgical management for subaxial cervical facet dislocations.

METHODS: A consistent surgical algorithm for cervical facet dislocation was applied over a 19-yr period and analyzed retrospectively in adults with acute unilateral or bilateral facet dislocation of the subaxial cervical spine. The primary endpoint was maintenance of early cervical alignment. The need for additional posterior instrumented fusion was determined.

RESULTS: A database search identified 96 patients (mean age = 37.9, range = 14-74 yr, 68 (70%) male. The most common affected levels were C4-C5 (30), C5-C6 (29), and C6-C7 (30). Bilateral dislocation occurred in 51 patients (53%). Seventy-eight (81%) patients had neurological deficits, 31 (32%) being complete (Abbreviated Injury Score A) spinal cord injuries. Preoperative closed reductionwas attempted in 60 (63%) patients, with 33 (55%) achieving satisfactory alignment. After anterior cervical discectomy, reduction, allograft placement, and instrumentation, a total of 92 (96%) patients had achieved satisfactory realignment. Median time to surgery was 13.27 h. Eight (8%) patients required posterior fixation due to intraoperative determination of incomplete realignment (4; 4%) and development of early progressive deformity (4; 4%). Mean follow-up was 4.5 mo (range 0.5-24 mo) with 33 (34%) patients lost to follow-up.

CONCLUSION: Anterior approaches are viable for reduction and stabilization of cervical facet dislocations. Further prospective studies are required to evaluate clinical and longterm success.

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Robot-assisted intravertebral augmentation corrects local kyphosis more effectively than a conventional fluoroscopy-guided technique

J Neurosurg Spine 30:289–295, 2019

Intravertebral augmentation (IVA) is a reliable minimally invasive technique for treating Magerl type A vertebral body fractures. However, poor correction of kyphotic angulation, the risk of cement leakage, and significant exposure to radiation (for the surgeon, the operating room staff, and the patient) remain significant issues. The authors conducted a study to assess the value of robot-assisted IVA (RA-IVA) for thoracolumbar vertebral body fractures.

METHODS The authors performed a retrospective, single-center study of patients who had undergone RA-IVA or conventional fluoroscopy-guided IVA (F-IVA) for thoracolumbar vertebral body fractures. Installation and operating times, guidance accuracy, residual local kyphosis, degree of restoration of vertebral body height, incidence of cement leakage, rate of morbidity, length of hospital stay, and radiation-related data were recorded.

RESULTS Data obtained in 30 patients who underwent RA-IVA were compared with those obtained in 30 patients who underwent F-IVA during the same period (the surgical indications were identical, but the surgeons were different). The mean ± SD installation time in the RA-IVA group (24 ± 7.5 minutes) was significantly shorter (p = 0.005) than that in the F-IVA group (26 ± 8 minutes). The mean operating time for the RA-IVA group (52 ± 11 minutes) was significantly longer (p = 0.026) than that for the F-IVA group (30 ± 11 minutes). All RA-IVAs and F-IVAs were Ravi’s scale grade A (no pedicle breach). The mean degree of residual local kyphosis (4.7° ± 3.15°) and the percentage of vertebral body height restoration (63.6% ± 21.4%) were significantly better after RA-IVA than after F-IVA (8.4° ± 5.4° and 30% ± 34%, respectively). The incidence of cement leakage was significantly lower in the RA-IVA group (p < 0.05). The mean length of hospital stay after surgery was 3.2 days for both groups. No surgery-related complications occurred in either group. With RA-IVA, the mean radiation exposure was 438 ± 147 mGy × cm for the patient and 30 ± 17 mGy for the surgeon.

CONCLUSIONS RA-IVA provided better vertebral body fracture correction than the conventional F-IVA. However, RAIVA requires more time than F-IVA.

 

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The diagnostic accuracy of detecting malignant transformation of low-grade glioma using O-(2-[18F]fluoroethyl)-l-tyrosine positron emission tomography

J Neurosurg 130:451–464, 2019

The diagnostic accuracy of O-(2-[18F]fluoroethyl)-l-tyrosine (FET) PET scanning in detecting the malignant transformation of low-grade gliomas (LGGs) is controversial. In this study, the authors retrospectively assessed the diagnostic potential of FET PET in patients with MRI-suspected malignant progression of LGGs that had previously been treated and the relationship between FET uptake and MRI and molecular biomarkers.

METHODS Forty-two patients who had previously undergone surgical or multimodal treatment for a histologically verified LGG were referred for FET PET assessment because of clinical signs and/or MRI findings suggestive of tumor progression. Maximal and mean tumor-to-brain ratios (TBRmax and TBRmean, respectively) on FET PET as well as kinetic FET PET parameters (time to peak [TTP] and time-activity curve [TAC]) were determined. Final diagnoses were confirmed histologically. The diagnostic accuracy of FET parameters, separately and combined, for the detection of malignant progression was evaluated using receiver operating characteristic (ROC) curve analysis. Possible predictors that might influence the diagnostic accuracy of FET PET were assessed using multiple linear regression analysis. Spearman’s rank correlation r method was applied to determine the correlation between TBRmax and TAC, and molecular biomarkers from tumor tissues.

RESULTS A total of 47 FET PET scans were obtained and showed no significant association between FET parameters and contrast enhancement on MRI. ROC curve analyses overall were unable to demonstrate any significant differentiation between nontransformed LGGs and LGGs that had transformed to high-grade gliomas when evaluating FET parameters separately or combined. After excluding the oligodendroglial subgroup, a significant difference was observed between nontransformed and transformed LGGs when combining FET parameters (i.e., TBRmax > 1.6, TAC describing a plateau or decreasing pattern, and TTP < 25 minutes), with the best result yielded by a combined analysis of TBRmax > 1.6 and TAC with a plateau or decreasing pattern (sensitivity 75% and specificity 83%, p = 0.003). The difference was even greater when patients who had previously undergone oncological treatment were also excluded (sensitivity 93% and specificity 100%, p = 0.001). Multiple linear regression analysis revealed that the presence of an oligodendroglial component (p = 0.029), previous oncological treatment (p = 0.039), and the combined FET parameters (p = 0.027) were significant confounding factors in the detection of malignant progression. TBRmax was positively correlated with increasing cell density (p = 0.040) and inversely correlated with IDH1 mutation (p = 0.006).

CONCLUSIONS A single FET PET scan obtained at the time of radiological and/or clinical progression seems to be of limited value in distinguishing transformed from nontransformed LGGs, especially if knowledge of the primary tumor histopathology is not known. Therefore, FET PET imaging alone is not adequate to replace histological confirmation, but it may provide valuable information on the location and delineation of active tumor tissue, as well as an assessment of tumor biology in a subgroup of LGGs.

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The modified retrosigmoid approach

Acta Neurochirurgica (2019) 161:417–423

The traditional retrosigmoid (RS) approach provides limited exposure of the inferior compartment of the CPA, while radical skull base approaches are demanding and associated with significant morbidity.

Methods This study outlines the relevant surgical anatomy and the different surgical steps of a modified retrosigmoid (MRS) approach. Results The MRS provides enhanced exposure of the CPA and deep vascular structures resulting from a modified RS craniotomy and limited exposure of the sigmoid sinus.

Conclusion In selected posterior fossa lesions, this cisternal approach is a straightforward corridor that can be routinely performed as a safe alternative to radical cranial base approaches.

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Effects of smoking on cervical disc arthroplasty

J Neurosurg Spine 30:168–174, 2019

Cigarette smoking can adversely affect bone fusion in patients who undergo anterior cervical discectomy and fusion. However, there is a paucity of data on smoking among patients who have undergone cervical disc arthroplasty (CDA). The present study aimed to compare the clinical and radiological outcomes of smokers to those of nonsmokers following CDA.

METHODS The authors retrospectively reviewed the records of consecutive patients who had undergone 1- or 2-level CDA for cervical disc herniation or spondylosis and had a minimum 2-year follow-up. All patients were grouped into a smoking group, which consisted of those who had consumed cigarettes within 6 months prior to the CDA surgery, or a nonsmoking group, which consisted of those who had not consumed cigarettes at all or within 6 months of the CDA. Clinical outcomes were evaluated according to the visual analog scale for neck and arm pain, Neck Disability Index, Japanese Orthopaedic Association Scale, and Nurick Scale at each time point of evaluation. Radiological outcomes were assessed using radiographs and CT for multiple parameters, including segmental range of motion (ROM), neutral lordotic curve, and presence of heterotopic ossification (HO).

RESULTS A total of 109 patients completed at least 2 years of follow-up and were analyzed (mean follow-up 42.3 months). There were 89 patients in the nonsmoking group and 20 in the smoking group. The latter group was younger and predominantly male (both p < 0.05) compared to the nonsmoking group. The two groups had similar improvements in all clinical outcomes after CDA compared to preoperatively. Radiological evaluations were also very similar between the two groups, except for two factors. The smoking group had well-preserved segmental ROM after CDA at an average of 8.1° (both pre- and postoperation). However, while the nonsmoking group remained mobile, segmental ROM decreased significantly (8.2° to 6.9°, p < 0.05) after CDA. There was a trend toward more HO development in the nonsmoking group than in the smoking group, but the difference was without significance (59.6% vs 50.0%, p = 0.43).

CONCLUSIONS During an average 3.5 years of follow-up after 1- and 2-level CDA, cigarette smokers and nonsmokers had similar improvements in clinical outcomes. Moreover, segmental mobility was slightly better preserved in smokers. Since smoking status did not negatively impact outcomes, CDA may be a reasonable option for selected patients who have smoked.

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Association between payer status and patient-reported outcomes in adult patients with lumbar spinal stenosis treated with decompression surgery

J Neurosurg Spine 30:198–210, 2019

Insurance disparities can have relevant effects on outcomes after elective lumbar spinal surgery. The aim of this study was to evaluate the association between private/public payer status and patient-reported outcomes in adult patients who underwent decompression surgery for lumbar spinal stenosis.

METHODS A sample of 100 patients who underwent surgery for lumbar spinal stenosis from 2012 to 2014 was evaluated as part of the prospectively collected Quality Outcomes Database at a single institution. Outcome measures were evaluated at 3 months and 12 months, analyzed in regard to payer status (private insurance vs Medicare/Veterans Affairs insurance), and adjusted for potential confounders.

RESULTS At baseline, patients had similar visual analog scale back and leg pain, Oswestry Disability Index, and EQ- 5D scores. At 3 months postintervention, patients with government-funded insurance reported significantly worse quality of life (mean difference 0.11, p < 0.001) and more leg pain (mean difference 1.26, p = 0.05). At 12 months, patients with government-funded insurance reported significantly worse quality of life (mean difference 0.14, p < 0.001). There were no significant differences at 3 months or 12 months between groups for back pain (p = 0.14 and 0.43) or disability (p = 0.19 and 0.15). Across time points, patients in both groups showed improvement at 3 months and 12 months in all 4 functional outcomes compared with baseline (p < 0.001).

CONCLUSIONS Both private and public insurance patients had significant improvement after elective lumbar spinal surgery. Patients with public insurance had slightly less improvement in quality of life after surgery than those with private insurance but still benefited greatly from surgical intervention, particularly with respect to functional status.

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Modified unilateral approach for mid-third giant bifalcine meningiomas: resection using an oblique surgical trajectory and falx window

Acta Neurochirurgica (2019) 161:327–332

Utilizing the shortest available trajectory is the norm for excision of meningiomas. However, such an approach for the mid-third/central falcine meningiomas risks the adjoining draining veins and eloquent cortex. A larger size and bilaterality of such tumors adds to the surgical challenge. Herein, we report the surgical nuances of a modified unilateral approach in patients operated for giant bilateral symmetrical mid-third falcine meningiomas.

Methods Five such patients were operated. The clinico-radiologic data was studied at presentation and at the follow-up. The meningiomas were subclassified into those that were located in the anterior and posterior half of the central falx, and their surgical trajectory was chosen accordingly. The tumor was excised through an oblique anterior or a posterior trajectory instead of directly working over the major draining veins and eloquent brain. The falx was incised to create a surgical window and access the tumor on the contralateral side.

Results Four patients had meningiomas in the anterior half and one in the posterior half of central falx. Simpson excision was grade II in four patients. One patient showed small residual tumor and underwent stereotactic radiosurgery. The overall mean follow-up of the patients was 9.2 months. All the patients had good clinical outcome.

Conclusions Giant bifalcine meningiomas can be safely resected through a unilateral approach. Falx opening serves as a window to remove the tumor from the contralateral side. An oblique trajectory rather than an end-on access to these tumors minimizes the risk of venous and cortical injury.

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The Application of the Novel Grading Scale (Lawton-Young Grading System) to Predict the Outcome of Brain Arteriovenous Malformation

Neurosurgery 84:529–536, 2019

A supplementary grading scale (Supplemented Spetzler-Martin grade, Supp-SM) was introduced in 2010 as a refinement of the SM system to improve preoperative risk prediction of brain arteriovenous malformations (AVMs).

OBJECTIVE: To determine the ability to predict surgical outcomes using the Supp-SM grading scale.

METHODS: This retrospective study was conducted on 200 patients admitted to the Helsinki University Hospital between 2000 and 2014. The validity of the Supp-SM and SM grading systems was compared using the area under the receiver operating characteristic (AUROC) curves, with respect to the change between preoperative and early (3-4 mo) as well as final postoperative modified Rankin Scale (mRS) scores.

RESULTS: The performance of the Supp-SM was superior to that of the SM grading scale in the early follow-up (3-4 mo): AUROC = 0.57 (95% confidence interval [CI]: 0.49-0.65) for SM and AUROC = 0.67 (95% CI: 0.60-0.75) for Supp-SM. The Supp-SM performance continued improving over SM at the late follow-up: AUROC=0.63 (95% CI: 0.55-0.71) for SM and AUROC = 0.70 (95% CI: 0.62-0.77) for Supp-SM. The perforating artery supply, which is not part of either grading system, plays an important role in the early follow-up outcome (P = .008; odds ratio: 2.95; 95% CI: 1.32-6.55) and in the late follow-up outcome (P < .001; odds ratio: 5.89; 95% CI: 2.49-13.91).

CONCLUSION: The Supp-SM grading system improves the outcome prediction accuracy and is a feasible alternative to the SMS, even for series with higher proportion of high-grade AVMs. However, perforators play important role on the outcome.

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The impact of adding posterior instrumentation to transpsoas lateral fusion

J Neurosurg Spine 30:211–221, 2019

Transpsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors’ knowledge, the literature on comparison of the two approaches is sparse.

METHODS The authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).

RESULTS A total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04–0.11) compared to TPP (0.03, 95% CI 0.01–0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10–0.26) compared to TPP (0.03, 95% CI 0.00–0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.

CONCLUSIONS These results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.

 

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Awake craniotomy versus craniotomy under general anesthesia without surgery adjuncts for supratentorial glioblastoma in eloquent areas

Acta Neurochirurgica (2019) 161:307–315

Awake craniotomy with electrocortical and subcortical mapping (AC) has become the mainstay of surgical treat- ment of supratentorial low-grade gliomas in eloquent areas, but not as much for glioblastomas.

Objective This retrospective controlled-matched study aims to determine whether AC increases gross total resections (GTR) and decreases neurological morbidity in glioblastoma patients as compared to resection under general anesthesia (GA, conventional). Methods Thirty-seven patients with glioblastoma undergoing AC were 1:3 controlled-matched with 111 patients undergoing GA for glioblastoma resection. The two groups were matched for age, gender, preoperative Karnofsky Performance Score (KPS), preoperative tumor volume, tumor location, and type of adjuvant treatment. Primary outcomes were extent of resection and the rate of postoperative complications. The secondary outcome was overall postoperative survival.

Results After matching, there were no significant differences in clinical variables between groups. Extent of resection was significantly higher in the AC group: mean extent of resection in the AC group was 94.89% (SD = 10.57) as compared to 70.30% (SD = 28.37) in the GA group (p = 0.0001). Furthermore, the mean rate of late minor postoperative complications in the AC group (0.03; SD = − 0.16) was significantly lower than in the GA group (0.15; SD = 0.39) (p = 0.05). No significant differences between groups were found for the other subgroups of postoperative complications. Moreover, overall postoperative survival did not differ between groups (p = 0.297).

Conclusion These findings suggest that resection of glioblastoma using AC is associated with significantly greater extent of resection and less late minor postoperative complications as compared with craniotomy under GA without the use of surgery adjuncts. However, due to certain limitations inherent to our study design (selection bias) and the absence of the use of surgery adjuncts in the GA group, we advocate for a prospective study to further build upon this evidence and study the use of AC in glioblastoma patients.

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