Month: February 2019

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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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Degradation of Neuronal Encoding of Speech in the Subthalamic Nucleus in Parkinson’s Disease

Neurosurgery 84:378–387, 2019

Most of the patients with Parkinson’s disease suffer from speech disorders characterized mainly by dysarthria and hypophonia.

OBJECTIVE: To understand the deterioration of speech in the course of Parkinson’s disease.

METHODS: We intraoperatively recorded single neuron activity in the subthalamic nucleus of 18 neurosurgical patients with Parkinson’s disease undergoing implantation of deep brain stimulator while patients articulated 5 vowel sounds.

RESULTS: Here, we report that single subthalamic neurons encode individual vowel phonemes and employ 1 of 2 encoding schemes: broad or sharp tuning. Broadly tuned units respond to all examined phonemes, each with a different firing rate, whereas sharply tuned ones are specific to 1 to 2 phonemes. We then show that in comparison with patients without speech deficits, the spiking activity in patients with speech disorders was lower during speech production, overt or imagined, but not during perception. However, patients with speech disorders employed a larger percentage of the neurons for the aforementioned tasks. Whereas the lower firing rates affect mainly sharply tuned units, the extra units used a broad tuning encoding scheme.

CONCLUSION: Our findings suggest mechanisms of neuronal degradation due to Parkinsonian speech disorders and their possible compensation. As impairment in sharply tuned units may be compensated by broadly tuned ones, the proposed compensation model appears to be suboptimal, lending support to the persistence of speech disorders in the course of the disease.

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Endoscopic endonasal surgery for epidermoid and dermoid cysts

J Neurosurg 130:368–378, 2019

Epidermoid and dermoid cysts may be found along the cranial base and are commonly resected via open transcranial approaches. The use of endoscopic endonasal approaches for resection of these tumors has been rarely reported.

METHODS The authors retrospectively reviewed the medical records of 21 patients who underwent endoscopic endonasal surgery for epidermoid and dermoid cyst resection at the University of Pittsburgh Medical Center between January 2005 and June 2014. Surgical outcomes and variables that might affect the extent of resection and complications were analyzed.

RESULTS Total resection (total removal of cyst contents and capsule) was achieved in 8 patients (38.1%), near-total resection (total removal of cyst contents, incomplete removal of cyst capsule) in 9 patients (42.9%), and subtotal resection (incomplete removal of cyst contents and capsule) in 4 patients (19%). Larger cyst volume (≥ 3 cm3) and intradural location (15 cysts) were significantly associated with nontotal resection (p = 0.008 and 0.0005, respectively). In the whole series, surgical complications were seen in 6 patients (28.6%). No complications were observed in patients with extradural cysts. Among the 15 patients with intradural cysts, the most common surgical complication was postoperative CSF leak (5 patients, 33.3%), followed by postoperative intracranial infection (4 patients, 26.7%). Larger cysts and postoperative CSF leak were associated with intracranial infection (p = 0.012 and 0.028, respectively). Subtotal resection was marginally associated with intracranial infection when compared with total resection (p = 0.091). All patients with neurological symptoms improved postoperatively with the exception of 1 patient with unchanged abducens nerve palsy.

CONCLUSIONS Endoscopic endonasal approaches may be effectively used for resection of epidermoid and dermoid cysts in carefully selected cases. These approaches are recommended for cases in which a total or near-total resection is possible in addition to a multilayer cranial base reconstruction with vascularized tissue to minimize the risk of intracranial infection.

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Natural history of cavernous sinus meningiomas

J Neurosurg 130:435–442, 2019

Meningiomas confined to the cavernous sinus (MCSs) are benign tumors. Due to the high risk of severe complications, the intracavernous surgical procedure was abandoned in favor of radiotherapy. However, the choice of treatment remains complicated due to the fact that the natural history of this lesion has not yet been described.

METHODS The authors studied the natural history of this lesion using a prospective series of 53 consecutive patients suffering from MCSs. The median follow-up duration was 10.2 years (range 2–25 years), from 1990 to 2016.

RESULTS Patients ranged in age from 30 to 72 years (mean 53 years). The meningiomas were diagnosed by major symptoms (mainly oculomotor palsy and neuralgia experienced in 28 patients), minor symptoms (headache, intermittent diplopia in 15 patients), or incidental findings (10 patients). Simple symptomatic treatment (short courses of cortico- steroids and carbamazepine) allowed patients to become asymptomatic in 19 (67.9%) of 28 cases experiencing major symptoms, and for 12 (80%) of 15 patients with initial minor symptoms (p < 0.0001). All patients with incidental findings remained asymptomatic. Forty four (83%) of 53 MCSs did not show any significant growth and 42 (80%) of 53 patients were not symptomatic at the end of follow-up (p < 0.001). The radiographic progression-free survival rates (± SD) at 5, 10, and 20 years were 90% ± 4.2%, 82% ± 5.7%, and 70% ± 10.2%, respectively. Five patients (9.4%) with no evidence of any effect of the initial medical treatment desired additional conventional radiation therapy.

CONCLUSIONS Because of the capricious, unpredictable, and slow growth of MCSs, together with high growth variability from one patient to the next, the symptomatic medical treatment of these tumors is a highly effective method. This series shows that these lesions are naturally, clinically, and radiologically indolent.

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Stereotactic Radiosurgery for Trigeminal Neuralgia in Patients With Multiple Sclerosis: A Multicenter Study

Neurosurgery 84:499–505, 2019

Facial pain response (PR) to various surgical interventions in patients with multiple sclerosis (MS)-related trigeminal neuralgia (TN) is much less optimal. No large patient series regarding stereotactic radiosurgery (SRS) has been published.

OBJECTIVE: To evaluate the clinical outcomes of MS-related TN treated with SRS.

METHODS: This is a retrospective cohort study. A total of 263 patients contributed by 9 member tertiary referral Gamma Knife centers (2 in Canada and 7 in USA) of the Interna- tional Gamma Knife Research Consortium (IGKRF) constituted this study.

RESULTS: The median latency period of PR after SRS was 1 mo. Reasonable pain control (Barrow Neurological Institute [BNI] Pain Scores I-IIIb) was achieved in 232 patients (88.2%). The median maintenance period from SRS was 14.1 months (range, 10 days to 10 years). The actuarial reasonable pain control maintenance rates at 1 yr, 2 yr, and 4 yr were 54%, 35%, and 24%, respectively. There was a correlation between the status of achieving BNI-I and the maintenance of facial pain recurrence-free rate. The median recurrence-free rate was 36 mo and 12.2 mo in patients achieving BNI-I and BNI > I, respectively (P = .046). Among 210 patients with known status of post-SRS complications, the new-onset of facial numbness (BNI-I or II) after SRS occurred in 21 patients (10%).

CONCLUSION: In this largest series SRS offers a reasonable benefit to risk profile for patients who have exhausted medical management. More favorable initial response to SRS may predict a long-lasting pain control.

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Origin of Syrinx Fluid in Syringomyelia: A Physiological Study

Neurosurgery 84:457–468, 2019

The origin of syrinx fluid is controversial.

OBJECTIVE: To elucidate themechanisms of syringomyelia associated with cerebrospinal fluid pathway obstruction and with intramedullary tumors, contrast transport from the spinal subarachnoid space (SAS) to syrinx was evaluated in syringomyelia patients.

METHODS: We prospectively studied patients with syringomyelia: 22 with Chiari I malformation and 16 with SAS obstruction-related syringomyelia before and 1 wk after surgery, and 9 with tumor-related syringomyelia before surgery only. Computed tomographymyelography quantified dye transport into the syrinx before and 0.5, 2, 4, 6, 8, 10, and 22 h after contrast injection by measuring contrast density in Hounsfield units (HU).

RESULTS: Before surgery, more contrast passed into the syrinx in Chiari I malformation related syringomyelia and spinal obstruction-related syringomyelia than in tumor-related syringomyelia, as measured by (1) maximum syrinx HU, (2) area under the syrinx concentration-time curve (HU AUC), (3) ratio of syrinx HU to subarachnoid cerebrospinal fluid (CSF; SAS) HU, and (4) AUC syrinx/AUC SAS. More contrast (AUC) accumulated in the syrinx and subarachnoid space before than after surgery.

CONCLUSION: Transparenchymal bulk flow of CSF from the subarachnoid space to syrinx occurs in Chiari I malformation-related syringomyelia and spinal obstruction-related syringomyelia. Before surgery, more subarachnoid contrast entered syringes associated with CSF pathway obstruction than with tumor, consistent with syrinx fluid originating from the subarachnoid space in Chiari I malformation and spinal obstruction-related syringomyelia and not from the subarachnoid space in tumor-related syringomyelia. Decompressive surgery opened subarachnoid CSF pathways and reduced contrast entry into syringes associated with CSF pathway obstruction.

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Artificial disc replacement versus fusion in patients with cervical degenerative disc disease with radiculopathy: 5-year outcomes from the National Swedish Spine Register

J Neurosurg Spine 30:159–167, 2019

The long-term efficacy of artificial disc replacement (ADR) surgery compared with fusion after decompression for the treatment of cervical degenerative disc disease and radiculopathy has not previously been investigated in a population-based setting.

METHODS All patients with cervical degenerative disc disease and radiculopathy who were in the national Swedish Spine Registry (Swespine) beginning in January 1, 2006, were eligible for the study. Follow-up information was obtained up to November 15, 2017. The authors compared, using propensity score matching, patients treated with anterior decompression and insertion of an ADR with patients who underwent anterior decompression combined with fusion surgery.
The primary outcome was the Neck Disability Index (NDI), a patient-reported function score ranging from 0% to 100%, with higher scores indicating greater disability and a minimum clinically important difference of > 15%.

RESULTS A total of 3998 patients (2018:1980 women/men) met the inclusion criteria, of whom 204 had undergone arthroplasty and 3794 had undergone fusion. After propensity score matching, 185 patients with a mean age of 49.7 years remained in each group. Scores on the NDI were approximately halved in both groups after 5 years, but without a significant mean difference in NDI (3.0%; 95% CI -8.4 to 2.4; p = 0.28) between the groups. There were no differences between the groups in EuroQol–5 Dimensions or in pain scores for the neck and arm.

CONCLUSIONS In patients with cervical degenerative disc disease and radiculopathy, decompression plus ADR surgery did not result in a clinically important difference in outcomes after 5 years, compared with decompression and fusion surgery.

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Detection rates and sites of unruptured intracranial aneurysms according to sex and age: an analysis of MR angiography–based brain examinations of 4070 healthy Japanese adults

J Neurosurg 130:573–578, 2019

The purpose of this study was to evaluate the detection rate and occurrence site according to patient sex and age of unruptured intracranial aneurysms detected through MRI and MR angiography (MRA).

METHODS A total of 4070 healthy adults 22 years or older (mean age [± SD] 50.6 ± 11.0 years; 41.9% women) who underwent a brain examination known as “Brain Dock” in the central Tokyo area between April 2014 and March 2015 were checked for unruptured saccular aneurysm using 3-T MRI/MRA. The following types of cases were excluded: 1) protrusions with a maximum diameter < 2 mm at locations other than arterial bifurcations, 2) conical protrusions at arterial bifurcations with a diameter < 3 mm, and 3) cases of suspected aneurysms with unclear imaging of the involved artery. When an aneurysm was definitively diagnosed, the case was included in the aneurysm group. The authors also investigated the relationship between aneurysm occurrence and risk factors (age, sex, smoking history, hypertension, diabetes, and hyperlipidemia).

RESULTS One hundred eighty-eight aneurysms were identified in 176 individuals (detection rate 4.32%), with the detection rate for women being significantly higher (6.2% vs 3.0%, p < 0.001). The average age in the aneurysm group was significantly higher than in the patients in whom aneurysms were not detected (53.0 ± 11.1 vs 50.5 ± 11.0 years). The detection rate tended to increase with age. The detection rates were 3.6% for people in their 30s, 3.5% for those in their 40s, 4.1% for those in their 50s, 6.9% for those in their 60s, and 6.8% for those in their 70s. Excluding persons in their 20s and 80s—age groups in which no aneurysms were discovered—the detection rate in women was higher in all age ranges. Of the individuals with aneurysms, 12 (6.81%) had multiple cerebral aneurysms; no sex difference was observed with respect to the prevalence of multiple aneurysms. Regarding aneurysm size, 2.0–2.9 mm was the most common size range, with 87 occurrences (46.3%), followed by 3.0–3.9 mm (67 [35.6%]) and 4.0–4.9 mm (20 [10.6%]). The largest aneurysm was 13 mm. Regarding location, the internal carotid artery (ICA) was the most common aneurysm site, with 148 (78.7%) occurrences. Within the ICA, C1 was the site of 46 aneurysms (24.5%); C2, 57 (30.3%); and C3, 29 (15.4%). The aneurysm detection rates for C2, C3, and C4 were 2.23%, 1.23%, and 0.64%, respectively, for women and 0.68%, 0.34%, and 0.21%, respectively, for men; ICA aneurysms were significantly more common in women than in men (5.27% vs 2.20%, p < 0.001). Multivariate logistic regression analysis revealed that age (p < 0.001, OR 1.03, 95% CI 1.01–1.04), female sex (p < 0.001, OR 2.28, 95% CI 1.64–3.16), and smoking history (p = 0.011, OR 1.52, 95% CI 1.10–2.11) were significant risk factors for aneurysm occurrence

CONCLUSIONS In this study, both female sex and older age were independently associated with an increased aneurysm detection rate. Aneurysms were most common in the ICA, and the frequency of aneurysms in ICA sites was markedly higher in women.

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Internal maxillary artery bypass for the treatment of complex middle cerebral artery aneurysms

Neurosurg Focus 46 (2):E10, 2019

The rapid innovation of the endovascular armamentarium results in a decreased number of indications for a classic surgical approach. However, a middle cerebral artery (MCA) aneurysm remains the best example of one for which results have favored microsurgery over endovascular intervention. In this study, the authors aimed to evaluate the experience and efficacy regarding surgical outcomes after applying internal maxillary artery (IMA) bypass for complex MCA aneurysms (CMCAAs).
METHODS All IMA bypasses performed between January 2010 and July 2018 in a single-center, single-surgeon practice were screened.
RESULTS In total, 12 patients (9 males, 3 females) with CMCAAs managed by high-flow IMA bypass were identified. The mean size of CMCAAs was 23.7 mm (range 10–37 mm), and the patients had a mean age of 31.7 years (range 14–56 years). The aneurysms were proximally occluded in 8 cases, completely trapped in 3 cases, and completely resected in 1 case. The radial artery was used as the graft vessel in all cases. At discharge, the graft patency rate was 83.3% (n = 10), and all aneurysms were completely eliminated (83.3%, n = 10) or greatly diminished (16.7%, n = 2) from the circulation. Postoperative ischemia was detected in 2 patients as a result of graft occlusion, and 1 patient presenting with subarachnoid hemorrhage achieved improved modified Rankin Scale scores compared to the preoperative status but retained some neurological deficits. Therefore, neurological assessment at discharge showed that 9 of the 12 patients experienced unremarkable outcomes. The mean interval time from bypass to angiographic and clinical follow-up was 28.7 months (range 2–74 months) and 53.1 months (range 19–82 months), respectively. Although 2 grafts remained occluded, all aneurysms were isolated from the circulation, and no patient had an unfavorable outcome.
CONCLUSIONS The satisfactory result in the present study demonstrated that IMA bypass is a promising method for the treatment of CMCAAs and should be maintained in the neurosurgical armamentarium. However, cases with intraoperative radical resection or inappropriate bypass recipient selection such as aneurysmal wall should be meticulously chosen with respect to the subtype of MCA aneurysm.

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Neck Remnants and the Risk of Aneurysm Rupture After Endovascular TreatmentWith Coiling or Stent-Assisted Coiling

Neurosurgery 84:421–427, 2019

Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies.

OBJECTIVE: To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms.

METHODS: We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond–Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture.

RESULTS: A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture.

CONCLUSION: We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.

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Symptomatic Adjacent Level Disease Requiring Surgery: Analysis of 10-Year Results From a Prospective, Randomized, Clinical Trial Comparing Cervical Disc Arthroplasty to Anterior Cervical Fusion

Neurosurgery 84:347–354, 2019

Ten-year follow-up data from the US Food and Drug Administration investigational device exemption trial comparing BRYAN  Cervical Disc (Medtronic, Dublin, Ireland) arthroplasty to anterior cervical discectomy and fusion (ACDF) demonstrated that disc arthroplasty maintained range of motion and improvements in overall success and neck disability.

OBJECTIVE: To compare the 10-yr rates of symptomatic adjacent level disease requiring surgery (SALDRS).

METHODS: Prospective randomized trial data were analyzed comparing BRYANR  Cervical Disc arthroplasty to ACDF for single-level cervical disc disease with concordant radiculopathy or myelopathy with clinicoradiographic analysis at 10 yr. Secondarily, 84-mo data were pooled with PRESTIGE   Cervical Disc arthroplasty (Medtronic) study data to provide overall rates of SALDRS.

RESULTS: Significantly greater overall success was maintained at every postoperative interval with an overall success rate of 81.3% with BRYAN  disc and 66.3% with ACDF (P = .005) without loss of motion preservation (8.69◦ vs 0.60◦). Reoperation at adjacent levels up to the 120-mo visit was 9.7% in the arthroplasty group and 15.8% in the ACDF group (P = .146). The combined data from BRYAN and Prestige ST demonstrate that BRYAN  and Prestige disc groups had a lower rate of second surgeries at the adjacent levels, up to the 84-mo visit, compared to the combined ACDF groups (6.9% vs 11.7%; P = .023).

CONCLUSION: Compared with ACDF, fewer patients with the BRYAN  disc required surgery for symptomatic adjacent level degeneration, but this did not achieve statistical significance. Analysis of combined study data using Bryan and Prestige discs shows significant differences in SADLRS as early as 7 yr.

 

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