Chiari I malformation: surgical technique, indications and limits

Acta Neurochir (2018) 160:213–217

Chiari malformation type I (CM-I) is a rare disease characterised by herniation of cerebellar tonsils below the foramen magnum with associated anomalies of posterior fossa. We describe here the surgical technique, indications and limits of surgical treatment.

Method The authors describe the surgical technique, including: posterior fossa decompression, opening of the foramen of Magendie and duraplasty in case of CM-I.

Conclusions Posterior fossa decompression plus duraplasty is a safe and effective procedure for patients with CM-I malformation.

Transdural Spinal Cord Herniation

World Neurosurg. (2018) 109:242-246.

Recognition of transdural spinal cord herniation has increased over the past decade. This condition remains little known, particularly outside the specialized fields of spinal surgery and neuroradiology, leading to a significant delay in clinical diagnosis and treatment. It should be considered among the differential diagnoses in patients with gradual-onset lower-limb weakness of presumed spinal origin. Reaching a diagnosis using magnetic resonance imaging is essential to refer patients for surgery before their myelopathy worsens.

We describe our surgical experience to untether the spinal cord by wrapping a dura graft around the spinal cord. Three case reports and a review of the literature are discussed.

The tethered effect of the arachnoid in vago-glossopharyngeal neuralgia: a real associated alternative mechanism?

Acta Neurochir (2018) 160:151–155

Vago-glossopharyngeal neuralgia (VGPN) is a rarely seen disease when compared to trigeminal neuralgia. When the pain is resistant to medical therapy, microvascular decompression can be performed if a vascular conflict is suspected on magnetic resonance imaging (MRI). In addition, arachnoid pathology may play a role in VGPN. We report two cases of VGPN caused by tethered arachnoid, associated with a vascular contact in which pain was reduced by freeing rootlets from arachnoid compression.

We report two cases relating to 50-year-old and 30-year-old men with a history of electric shooting pain triggered by swallowing in the right pharyngeal and auricular regions. Preoperative MRI documented a neurovascular conflict in the first case and an arachnoid cyst in the second. Surgery was performed via a retrosigmoid craniotomy. In both cases, the intraoperative findings documented a tethered arachnoid membrane compressive to cranial nerves IX and X. Untethering was performed by liberation of the rootlets from the arachnoid with microvascular decompression. No additional rhizotomy was performed. The postoperative course was uneventful and pain was relieved in the first case and decreased in the second.

In VGPN, a tethered arachnoid may play a role in causing the neuralgia, either alone or associated with a neuro-vascular conflict.

Developing an Algorithm for Optimizing Care of Elderly Patients With Glioblastoma

Neurosurgery 82:64–75, 2018

Elderly patients with glioblastoma have an especially poor prognosis; optimizing their medical and surgical care remains of paramount importance.

OBJECTIVE: To investigate patient and treatment characteristics of elderly vs nonelderly patients and develop an algorithm to predict elderly patients’ survival.

METHODS: Retrospective analysis of 554 patients (mean age=60.8; 42.0% female) undergoing first glioblastoma resection or biopsy at our institution (2005-2011).

RESULTS: Of the 554 patients, 218 (39%) were elderly (≥65 yr). Compared with nonelderly, elderly patients were more likely to receive biopsy only (26% vs 16%), have ≥1 medical comorbidity (40% vs 20%), and develop postresection morbidity (eg, seizure, delirium; 25% vs 14%), and were less likely to receive temozolomide (TMZ) (78% vs 90%) and gross total resection (31% vs 45%). To predict benefit of resection in elderly patients (n = 161), we identified 5 factors known in the preoperative period that predicted survival in a multivariate analysis. We then assigned points to each (1 point: Charlson comorbidity score >0, subtotal resection, tumor >3 cm; 2 points: preoperative weakness, Charlson comorbidity score >1, tumor >5 cm, age >75 yr; 4 points: age >85 yr). Having 3 to 5 points (n = 78, 56%) was associated with decreased survival compared to 0 to 2 points (n = 41, 29%, 8.5 vs 16.9 mo; P = .001) and increased survival compared to 6 to 9 points (n = 20, 14%, 8.5 vs 4.5 mo; P < .001). Patients with 6 to 9 points did not survive significantly longer than elderly patients receiving biopsy only (n = 57, 4.5 vs 2.7 mo; P = .58).

CONCLUSION: Further optimization of the medical and surgical care of elderly glioblastoma patients may be achieved by providing more beneficial therapies while avoiding unnecessary resection in those not likely to receive benefit from this intervention.

 

Microvascular decompression for glossopharyngeal neuralgia: a retrospective analysis of 228 cases

Acta Neurochir (2018) 160:117–123

Glossopharyngeal neuralgia (GPN) is an uncommon craniofacial pain syndrome caused by neurovascular conflict. Compared to trigeminal neuralgia or hemifacial spasm, the incidence of GPN was very low. Until now, little is known about the long-term outcome following microvascular decompression (MVD) process.

Methods Between 2006 and 2016, 228 idiopathic GPN patients underwent MVD in our department. Those cases were retrospectively reviewed with emphasis on intraoperative findings and long-term postoperative outcomes. The average period of follow-up was 54.3 ± 6.2 months.

Results Intraoperatively, the culprit was identified as the posterior inferior cerebellar artery (PICA) in 165 cases (72.3%), the vertebral artery (VA) in 14 (6.1%), vein in 10 (4.4%), and a combination of multiple arteries or venous offending vessels in 39 (17.2%). The immediately postoperative outcome was excellent in 204 cases (89.5%), good in 12 (5.3%), fair in 6 (2.6%) and poor in 6 (2.6%). More than 5-year follow-up was obtained in 107 cases (46.9%), which presented as excellent in 93 (86.9%), good in 6 (5.6%), fair in 3 (2.8%) and poor in 5 (4.7%). Thirty-seven (16.2%) of the patients experienced some postoperative neurological deficits immediately, such as dysphagia, hoarseness and facial paralysis, which has been improved at the last follow-up in most cases, except 2.

Conclusions This investigation demonstrated that MVD is a safe and effective remedy for treatment of GPN.

Posterior Inferior Cerebellar Artery/Vertebral Artery Subarachnoid Hemorrhage: A Comparison of Saccular vs Dissecting Aneurysms

Neurosurgery 82:93–98, 2018

Two distinct categories of aneurysms are described in relation to the posterior inferior cerebellar artery (PICA) and vertebral artery (VA): saccular (SA) and dissecting (DA) types. This distinction is often unrecognized because abnormalities here are uncommon and most studies are small.

OBJECTIVE: To determine if there are any differences in the clinical presentation, inhospital course, or outcomes in patients with DA vs SA of the PICA or VA.

METHODS: Thirty-eight patients with a VA or PICA aneurysm were identified from a departmental subarachnoid hemorrhage database and categorized into DA or SA types. Prospectively collecteddemographic and outcomedata (length of stay, discharge Glasgow Outcome Score) were supplemented by abstracting records for procedural data (extraventricular drain [EVD], ventriculoperitoneal [VP] shunt, tracheostomy, and nasogastric feeding). Univariate, binary logistic regression, and Cox regression analysis was used to compare patients with SA vs DA.

RESULTS: Three aneurysms related to arteriovenous malformation were excluded. Five patients were conservatively managed. Of the 30 treated cases, more patients with a DA presented in poor grade (6/13 vs 2/17 SA; P = .035).More DA patients required an EVD (85% vs 29%; P = .003), VP shunt (54% vs 6%; P = .003), tracheostomy (46% vs 6%; P < .01), and nasogastric feeding (85% vs 35%; P = .007). The median length of stay (41 vs 17 d, P < .001) was longer, and the age and injury severity adjusted odds of discharge home were significantly lower in the DA group (P=.008). Thirty-daymortality was not significantly different (23% of DA vs 24% of SA; P = .2).

CONCLUSION: The presentation, clinical course, and outcomes differ in patients with DA vs SA of the PICA and VA.

Lumbar Disk Arthroplasty for Degenerative Disk Disease

World Neurosurg. (2018) 109:188-196.

Low back pain is the principal cause of long-term disability worldwide. We intend to address one of its main causes, degenerative disk disease, a spinal condition involving degradation of an intervertebral disk.

Following unsuccessful conservative treatment, patients may be recommended for surgery. The two main surgical treatments for lumbar degenerative disk disease are lumbar fusion: traditional standard surgical treatment and lumbar disk arthroplasty, also known as lumbar total disk replacement. Lumbar fusion aims to relieve pain by fusing vertebrae together to eliminate movement at the joint, but it has been criticized for problems involving insignificant pain relief, a reduced range of motion, and an increased risk of adjacent segment degeneration. This leads to development of the lumbar total disk replacement technique, which aims to relieve pain replacing a degenerated intervertebral disk with a moveable prosthesis, thus mimicking the functional anatomy and biomechanics of a native intervertebral disk. Over the years a large range of prosthetic disks has been developed.

The efficacy and current evidence for these prostheses are discussed in this review. The results of this study are intended to guide clinical practice and future lumbar total disk replacement device choice and design.

Analysis of saccular aneurysms in the Barrow Ruptured Aneurysm Trial

J Neurosurg 128:120–125, 2018

The Barrow Ruptured Aneurysm Trial (BRAT) is a prospective, randomized trial in which treatment with clipping was compared to treatment with coil embolization. Patients were randomized to treatment on presentation with any nontraumatic subarachnoid hemorrhage (SAH). Because all other randomized trials comparing these 2 types of treatments have been limited to saccular aneurysms, the authors analyzed the current BRAT data for this subgroup of lesions.

METHODS The primary BRAT analysis included all sources of SAH: nonaneurysmal lesions; saccular, blister, fusiform, and dissecting aneurysms; and SAHs from an aneurysm associated with either an arteriovenous malformation or a fistula. In this post hoc review, the outcomes for the subgroup of patients with saccular aneurysms were further analyzed by type of treatment. The extent of aneurysm obliteration was adjudicated by an independent neuroradiologist not involved in treatment.

RESULTS Of the 471 patients enrolled in the BRAT, 362 (77%) had an SAH from a saccular aneurysm. Patients with saccular aneurysms were assigned equally to the clipping and the coiling cohorts (181 each). In each cohort, 3 patients died before treatment and 178 were treated. Of the 178 clip-assigned patients with saccular aneurysms, 1 (1%) was crossed over to coiling, and 64 (36%) of the 178 coil-assigned patients were crossed over to clipping. There was no statistically significant difference in poor outcome (modified Rankin Scale score > 2) between these 2 treatment arms at any recorded time point during 6 years of follow-up. After the initial hospitalization, 1 of 241 (0.4%) clipped saccular aneurysms and 21 of 115 (18%) coiled saccular aneurysms required retreatment (p < 0.001). At the 6-year follow-up, 95% (95/100) of the clipped aneurysms were completely obliterated, compared with 40% (16/40) of the coiled aneurysms (p < 0.001). There was no difference in morbidity between the 2 treatment groups (p = 0.10).

CONCLUSIONS In the subgroup of patients with saccular aneurysms enrolled in the BRAT, there was no significant difference between modified Rankin Scale outcomes at any follow-up time in patients with saccular aneurysms assigned to clipping compared with those assigned to coiling (intent-to-treat analysis). At the 6-year follow-up evaluation, rates of retreatment and complete aneurysm obliteration significantly favored patients who underwent clipping compared with those who underwent coiling. Clinical trial registration no.: NCT01593267 (clinicaltrials.gov)

 

Early Postoperative Complications for Elderly Patients Undergoing Single-Level Decompression for Lumbar Disc Herniation, Ligamentous Hypertrophy, or Neuroforaminal Stenosis

Neurosurgery 81:1005–1010, 2017

Lumbar decompression for disc herniation is frequently performed on elderly patients, and this trend will continue as the population ages. Clinical reports on the complications of lumbar discectomy show good results and cost effectiveness in young or middle-aged patients.

OBJECTIVE: To assess and compare the morbidity of single-level lumbar disc surgery for radicular pain in a cohort of patients greater than 80 yr of age to that of a middle-aged cohort.

METHODS: A total of 9451 patients who received a single-level lumbar decompression procedure for disc displacement without myelopathy were retrospectively selected from a multicenter validated surgical database from the American College of Surgeons National Surgical Quality Improvement Program. A cohort with 485 patients greater than 80 yr of age (80+) was compared with a middle-aged cohort with 8966 patients between 45 and 65 yr. Preoperative comorbidity and postoperative outcome variables observed included mortality, myocardial infarction, return to the operating room, sepsis, deep vein thrombosis, transfusions, cardiac arrest necessitating cardiopulmonary resuscitation, coma greater than 24 h, urinary tract infection, acute renal failure, use of ventilator greater than 24 h, pulmonary embolism, pneumonia, wound dehiscence, and postoperative infection.

RESULTS: The preoperative comorbidities and characteristics were significantly different between the middle-aged and the 80+ cohorts, with the older cohort having many more preoperative comorbidities. There was statistically significantly greater postoperative morbidity among the 80+ cohort regarding pulmonary embolism (0.8% vs 0.2%, P = .037), intra/postoperative transfusion requirement (1.9% vs 0.7%, P = .01), urinary tract infection (1.2% vs 0.3%, P = .011), and 30-d mortality (0.4% vs 0.1%, P = .046).

CONCLUSION: In this large sample of patients who received a single-level lumbar decompression procedure for disc displacement without myelopathy, elderly patients, particularly with American Society of Anesthesiologists class 3 and 4, had a statistically significant increase in morbidity and mortality, but the overall risk of complications remains low.

 

Clinical and radiological results of posterior cervical foraminotomy at two or three levels: a 3-year follow-up

Acta Neurochir (2017) 159:2369–2377

Single-level unilateral posterior cervical foraminotomy is regarded as a safe method. However, the outcomes of posterior cervical foraminotomy performed on two or three levels are uncertain and debated. We aimed to analyze the long-term clinical and radiological outcomes of posterior cervical foraminotomy at two or three levels.

Methods From September 2008 to December 2011, a total of 42 patients who underwent a posterior cervical foraminotomy at two or three levels and were followed for at least 3 years were analyzed with retrospective cohort study. Clinical assessments were performed using the visual analog scale (VAS), neck disability index (NDI) and modified MacNab criteria. Radiological evaluation included the assessment of static and dynamic lateral radiographs to identify instability, postlaminectomy kyphotic deformity, adjacent segmental degeneration (ASD), and focal degeneration.

Results The mean VAS improved from preoperative score 8.5 ± 0.3 to postoperative score 1.8 ± 0.5 significantly. The mean presenting NDI score was 32.9 ± 2.0 and the mean postoperative NDI score was 14.2 ± 1.3. Improvement of radiculopathy was displayed in 39 patients (92.9%). During radiological evaluation, no significant change in disc height related to ASD and focal degeneration was noted. However, we confirmed one patient with radiological instability and one patient with radiological postlaminectomy kyphotic deformity.

Conclusions Posterior cervical foraminotomy at two or three levels is fairly effective for treating patients with cervical radiculopathy, and results in long-lasting pain relief and improved quality of life in nearly all patients. However, further studies of three levels that include more patients are needed.

Symmetry of the arcuate fasciculus and its impact on language performance of patients with brain tumors in the language-dominant hemisphere

J Neurosurg 127:1407–1416, 2017

Cerebral damage in frontal, parietal, and temporal brain areas and, probably more importantly, their interconnections can lead to deficits in language. However, neural plasticity and repair allow the brain to partly compensate for neural injury, mediated by both functional and structural changes. In this study, the authors sought to systematically investigate the relationship between language performance in brain tumor patients and structural perisylvian pathways (i.e., the arcuate fasciculus [AF]) using probabilistic fiber tracking on diffusion tensor imaging. The authors used a previously proposed model in which the AF is divided into anterior, long, and posterior segments. The authors hypothesized that right-handed patients with gliomas in the language-dominant (left) hemisphere would benefit from a more symmetrical or right-lateralized language pathway in terms of better preservation of language abilities. Furthermore, they investigated to what extent specific tumor characteristics, including proximity to the AF, affect language outcome in such patients.

METHODS Twenty-seven right-handed patients (12 males and 15 females; mean age 52 ± 16 years) with 11 low-grade and 16 high-grade gliomas of the left hemisphere underwent 3-T diffusion-weighted MRI (30 directions) and language assessment as part of presurgical planning. For a systematic quantitative evaluation of the AF, probabilistic fiber tracking with a 2 regions of interest approach was carried out. Volumes of the 3 segments of both hemispheric AFs were evaluated by quantifying normalized and thresholded pathways. Resulting values served to generate the laterality index of the AFs.

RESULTS Patients without language deficits tended to have an AF that was symmetric or lateralized to the right, whereas patients with deficits in language significantly more often demonstrated a left-lateralized posterior segment of the AF. Patients with high-grade gliomas had more severe language deficits than those with low-grade gliomas. Backward logistic regression revealed the laterality index of the posterior AF segment and tumor grade as the only independent statistically significant predictors for language deficits in this cohort.

CONCLUSIONS In addition to the well-known fact that tumor entity influences behavioral outcome, the authors’ findings suggest that the right homologs of structural language-associated pathways could be supportive for language function and facilitate compensation mechanisms after brain damage in functionally eloquent areas. This further indicates that knowledge about preoperative functional redistribution (identified by neurofunctional imaging) increases the chance for total or near-total resections of tumors in eloquent areas. In the future, longitudinal studies with larger groups are mandatory to overcome the methodological limitations of this cross-sectional study and to map neuroplastic changes associated with language performance and rehabilitation in brain tumor patients.

 

Magnetic resonance imaging characteristics and the prediction of outcome of vestibular schwannomas following Gamma Knife radiosurgery

J Neurosurg 127:1384–1391, 2017

Gamma Knife surgery (GKS) is a promising treatment modality for patients with vestibular schwannomas (VSs), but a small percentage of patients have persistent postradiosurgical tumor growth. The aim of this study was to determine the clinical and quantitative MRI features of VS as predictors of long-term tumor control after GKS.

METHODS The authors performed a retrospective study of all patients with VS treated with GKS using the Leksell Gamma Knife Unit between 2005 and 2013 at their institution. A total of 187 patients who had a minimum of 24 months of clinical and radiological assessment after radiosurgery were included in this study. Those who underwent a craniotomy with tumor removal before and after GKS were excluded. Study patients comprised 85 (45.5%) males and 102 (54.5%) females, with a median age of 52.2 years (range 20.4–82.3 years). Tumor volumes, enhancing patterns, and apparent diffusion coefficient (ADC) values were measured by region of interest (ROI) analysis of the whole tumor by serial MRI before and after GKS.

RESULTS The median follow-up period was 60.8 months (range 24–128.9 months), and the median treated tumor volume was 3.54 cm3 (0.1–16.2 cm3). At last follow-up, imaging studies indicated that 150 tumors (80.2%) showed decreased tumor volume, 20 (10.7%) had stabilized, and 17 (9.1%) continued to grow following radiosurgery. The postradiosurgical outcome was not significantly correlated with pretreatment volumes or postradiosurgical enhancing patterns. Tumors that showed regression within the initial 12 months following radiosurgery were more likely to have a larger volume reduction ratio at last follow-up than those that did not (volume reduction ratio 55% vs 23.6%, respectively; p < 0.001). Compared with solid VSs, cystic VSs were more likely to regress or stabilize in the initial postradiosurgical 6–12-month period and during extended follow-up. Cystic VSs exhibited a greater volume reduction ratio at last follow-up (cystic vs solid: 67.6% ± 24.1% vs 31.8% ± 51.9%; p < 0.001). The mean preradiosurgical maximum ADC (ADCmax) values of all VSs were significantly higher for those with tumor regression or stabilization at last follow-up compared with those with progression (2.391 vs 1.826 × 10-3 mm2/sec; p = 0.010).

CONCLUSIONS Loss of central enhancement after radiosurgery was a common phenomenon, but it did not correlate with tumor volume outcome. Preradiosurgical MRI features including cystic components and ADCmax values can be helpful as predictors of treatment outcome.

Intrawound Vancomycin Decreases the Risk of Surgical Site Infection After Posterior Spine Surgery: A Multicenter Analysis

Spine 2018;43:65–71

Study Design. Secondary analysis of data from a prospective multicenter observational study.

Objective. The aim of this study was to evaluate the occurrence of surgical site infection (SSI) in patients with and without intrawound vancomycin application controlling for confounding factors associated with higher SSI after elective spine surgery.

Summary of Background Data. SSI is a morbid and expensive complication associated with spine surgery. The application of intrawound vancomycin is rapidly emerging as a solution to reduce SSI following spine surgery. The impact of intrawound vancomycin has not been systematically studied in a welldesigned multicenter study.

Methods. Patients undergoing elective spine surgery over a period of 4 years at seven spine surgery centers across the United States were included in the study. Patients were dichotomized on the basis of whether intrawound vancomycin was applied. Outcomes were occurrence of SSI within postoperative 30 days and SSI that required return to the operating room (OR). Multivariable random-effect log-binomial regression analyses were conducted to determine the relative risk of having an SSI and an SSI with return to OR.

Results. A total of 2056 patients were included in the analysis. Intrawound vancomycin was utilized in 47% (n=966) of patients. The prevalence of SSI was higher in patients with no vancomycin use (5.1%) than those with use of intrawound vancomycin (2.2%). The risk of SSI was higher in patients in whom intrawound vancomycin was not used (relative risk (RR) – 2.5, P<0.001), increased number of levels exposed (RR -1.1, P=0.01), and those admitted postoperatively to intensive care unit (ICU) (RR -2.1, P=0.005). Patients in whom intrawound vancomycin was not used (RR -5.9, P<0.001), increased number of levels were exposed (RR-1.1, P=0.001), and postoperative ICU admission (RR -3.3, P<0.001) were significant risk factors for SSI requiring a return to the OR.

Conclusion. The intrawound application of vancomycin after posterior approach spine surgery was associated with a reduced risk of SSI and return to OR associated with SSI.

Level of Evidence: 2

Relative lumbar lordosis and lordosis distribution index

Neurosurg Focus 43 (6):E5, 2017

The subtraction of lumbar lordosis (LL) from the pelvic incidence (PI) offers an estimate of the LL required for a given PI value. Relative LL (RLL) and the lordosis distribution index (LDI) are PI-based individualized measures. RLL quantifies the magnitude of lordosis relative to the ideal lordosis as defined by the magnitude of PI. LDI defines the magnitude of lower arc lordosis in proportion to total lordosis. The aim of this study was to compare RLL and PI – LL for their ability to predict postoperative complications and their correlations with health-related quality of life (HRQOL) scores.
METHODS Inclusion criteria were ≥ 4 levels of fusion and ≥ 2 years of follow-up. Mechanical complications were proximal junctional kyphosis/proximal junctional failure, distal junctional kyphosis/distal junctional failure, rod breakage, and implant-related complications. Correlations between PI – LL, RLL, PI, and HRQOL were analyzed using the Pearson correlation coefficient. Mechanical complication rates in PI – LL, RLL, LDI, RLL, and LDI interpreted together, and RLL subgroups for each PI – LL category were compared using chi-square tests and the exact test. Predictive models for mechanical complications with RLL and PI – LL were analyzed using binomial logistic regressions.
RESULTS Two hundred twenty-two patients (168 women, 54 men) were included. The mean age was 52.2 ± 19.3 years (range 18–84 years). The mean follow-up was 28.8 ± 8.2 months (range 24–62 months). There was a significant correlation between PI – LL and PI (r = 0.441, p < 0.001), threatening the use of PI – LL to quantify spinopelvic mismatch for different PI values. RLL was not correlated with PI (r = -0.093, p > 0.05); therefore, it was able to quantify divergence from ideal lordosis for all PI values. Compared with PI – LL, RLL had stronger correlations with HRQOL scores (p < 0.05). Discrimination performance was better for the model with RLL than for PI – LL. The agreement between RLL and PI – LL was high (k = 0.943, p < 0.001), moderate (k = 0.455, p < 0.001), and poor (k = -0.154, p = 0.343), respectively, for large, average, and small PI sizes. When analyzed by RLL, each PI – LL category was further divided into distinct groups of patients who had different mechanical complication rates (p < 0.001).
CONCLUSIONS Using the formula of PI – LL may be insufficient to quantify normolordosis for the whole spectrum of PI values when applied as an absolute numeric value in conjunction with previously reported population-based average thresholds of 10° and 20°. Schwab PI – LL groups were found to constitute an inhomogeneous group of patients. RLL offers an individualized quantification of LL for all PI sizes. Compared with PI – LL, RLL showed a greater association with both mechanical complications and HRQOL. The use of RLL and LDI together, instead of PI – LL, for surgical planning may result in lower mechanical complication rates and better long-term HRQOL.

Differentiating brain radionecrosis from tumour recurrence: a role for contrast-enhanced ultrasound?

Acta Neurochir (2017) 159:2405–2408

Differentiating radionecrosis from tumour recurrence is a major issue in neuro-oncology. Conventional imaging is far from being validated as an alternative to histologicalassessment.

We report the case of a patient operated on for suspected recurrence of brain metastasis 9 months after cyberknife radiosurgery. While magnetic resonance imaging showed strong enhancement of the lesion, intraoperative contrast-enhanced ultrasonography (CEUS) surprisingly did
not—different from what is expected for brain metastases.

Histopathological examination documented radionecrosis. For the first time, we describe radionecrosis with CEUS; further investigation is needed; however, the lack of enhancement could represent an important hallmark in differential diagnosis with neoplastic tissue.

What Is the Fate of Pseudarthrosis Detected 1 Year After Anterior Cervical Discectomy and Fusion?

Spine 2018;43:E23–E28

Objective. To investigate the consequences and appropriate management of pseudarthrosis after anterior cervical discectomy and fusion (ACDF).

Summary of Background Data. Pseudarthrosis is a frequent complication of ACDF and causes unsatisfactory results. Little is known about long-term prognosis of detecting pseudarthrosis 1 year after ACDF.

Methods. Eighty-nine patients with a minimum 2-year followup were included. ACDF surgery using allograft and plating was performed: single-level in 51 patients, two-level in 26 patients, and three-level in 12 patients. Presence of pseudarthrosis was evaluated 1 year postoperatively and then the nonunion segments were re-evaluated 2 years postoperatively. Demographic data were assessed to identify the risk factors associated with pseudarthrosis. A visual analogue scale for neck/arm pain and the Neck Disability Index were analyzed preoperatively and at 1 and 2 years postoperatively.

Results. Pseudarthrosis was detected in 29 patients (32.6%) 1 year postoperatively: 15of 51 patients after single-level surgery, 9 of 26 patients after two-level surgery, and 5 of 12 patients after three-level surgery. Only eight patients showed persistent nonunion at 2 years: 3 of 15 patients after single-level surgery, 3 of 9 after two-level surgery, and 2 of 5 after three-level surgery. The remaining 21 patients (72.4%) achieved bony fusion 2 years postoperatively without any intervention. Patients who underwent two-level or three-level ACDF had a significantly higher pseudarthrosis rate than those who underwent single-level ACDF, with odds ratios of 1.844 and 3.147, respectively. The improvements in visual analogue scale for neck pain and Neck Disability Index scores in the persistent nonunion group were significantly lower than those in the final union group at 2 years.

Conclusion. Patients with pseudarthrosis detected 1 year postoperatively may be observed without any intervention because approximately 70% of them will eventually fuse by the 2-year point. Early revision could, however, be considered if the pseudarthrosis is associated with considerable neck pain after multilevel ACDF.

Level of Evidence: 3

Comparison of endovascular and microsurgical management of 208 basilar apex aneurysms

J Neurosurg 127:1342–1352, 2017

The deep and difficult-to-reach location of basilar apex aneurysms, along with their location near critical adjacent perforating arteries, has rendered the perception that microsurgical treatment of these aneurysms is risky. As a result, these aneurysms are considered more suitable for treatment by endovascular intervention. The authors attempt to compare the immediate and long-term outcomes of microsurgery versus endovascular therapy for this aneurysm subtype.

METHODS A prospectively maintained database of 208 consecutive patients treated for basilar apex aneurysms between 2000 and 2012 was reviewed. In this group, 161 patients underwent endovascular treatment and 47 were managed microsurgically. The corresponding records were analyzed for presenting characteristics, postoperative complications, discharge status, and Glasgow Outcome Scale (GOS) scores up to 1 year after treatment and compared using chi-square and Student t-tests.

RESULTS Among these 208 aneurysms, 116 (56%) were ruptured, including 92 (57%) and 24 (51%) of the endovascularly and microsurgically managed aneurysms, respectively. The average Hunt and Hess grade was 2.4 (2.4 in the endovascular group and 2.2 in the microsurgical group; p = 0.472). Postoperative complications of cranial nerve deficits and hemiparesis were more common in patients treated microsurgically than endovascularly (55.3% vs 16.2%, p < 0.05; and 27.7% vs 10.6%, p < 0.05, respectively). However, aneurysm remnants and need for retreatment were more common in the endovascular than the microsurgical group (41.3% vs 2.3%, p < 0.05; and 10.6% vs 0.0%, p < 0.05, respectively). Stent placement significantly reduced the need for retreatment. Rehemorrhage rates and average GOS score at discharge and 1 year after treatment were not statistically different between the two treatment groups.

CONCLUSIONS Patients with basilar apex aneurysms were significantly more likely to be treated via endovascular management, but compared with those treated microsurgically, they had higher rates of recurrence and need for retreatment. The current study did not detect an overall difference in outcomes at discharge and 1 year after either treatment modality. Therefore, in a select group of patients, microsurgical treatment continues to play an important role.

Minimally Invasive Transforaminal Lumbar Interbody Fusion: Meta-analysis of the Fusion Rates. What is the Optimal Graft Material?

Neurosurgery 81:958–971, 2017

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is an increasingly popular procedure with several potential advantages over traditional open TLIF.

OBJECTIVE: The current study aimed to compare fusion rates of different graft materials used in MIS-TLIF, via meta-analysis of the published literature.

METHODS: A Medline search was performed and a database was created including patient’s type of graft, clinical outcome, fusion rate, fusion assessment modality, and duration of follow-up. Meta-analysis of the fusion rate was performed using StatsDirect software (StatsDirect Ltd, Cheshire, United Kingdom).

RESULTS: A total of 1533 patients from 40 series were included. Fusion rates were high, ranging from 91.8% to 99%. The imaging modalities used to assess fusion were computed tomography scans (30%) and X-rays (70%). Comparison of all recombinant human bone morphogenetic protein (rhBMP) series with all non-rhBMP series showed fusion rates of 96.6% and 92.5%, respectively. The lowest fusion rate was seen with isolated use of autologous local bone (91.8%). The highest fusion ratewas observed with combination of autologous local bone with bone extender and rhBMP (99.1%). The highest fusion rate without the use ofBMPwas seen with autologous local bone+bone extender (93.1%). The reported complication rate ranged from 0% to 35.71%. Clinical improvement was observed in all studies.

CONCLUSION: Fusion rates are generally high with MIS-TLIF regardless of the graft material used. Given the potential complications of iliac bone harvesting and rhBMP, use of other bone graft options for MIS-TLIF is reasonable. The highest fusion rate without the use of rhBMP was seen with autologous local bone plus bone extender (93.1%).

 

Clinical features and surgical outcomes of patients with skull base chordoma

J Neurosurg 127:1257–1267, 2017

Skull base chordoma is relatively rare, and a limited number of reports have been published regarding its clinical features. Moreover, the factors associated with extent of resection, as well as the value of marginal resection for long-term survival, are still in question for this disease. The objective of this study was to investigate these factors by evaluating their clinical features and surgical outcomes.

METHODS A retrospective analysis of 238 patients with skull base chordomas, who met the inclusion criteria, was performed. This study summarized the clinical features, selection of approaches, degree of resection, and postoperative complications by statistical description analyses; proposed modified classifications of tumor location and bone invasion; studied the contributions of the clinical and radiological factors to the extent of resection by Pearson c2, ANOVA, rank test, and binary logistic regression analysis; and estimated the differences in overall survival and progression-free survival rates with respect to therapeutic history, classification of tumor location, extent of bone invasion, and extent of tumor resection by the Kaplan-Meier method. A p value < 0.05 was considered statistically significant.

RESULTS The study included 140 male and 98 female patients with a mean age of 38.1 years. Headache and neck pain (33.2%) and diplopia (29%) were the most common initial symptoms. Sphenoclival type accounted for the largest proportion of tumor location (59.2%); endophytic chordoma was the more common type of bone invasion (81.5%). Lateral open approaches were performed in two-thirds of the study population (78.6%). The rate of marginal resection was 66%, composed of gross-total resection (11.8%) and near-total resection (54.2%). Meningitis (8%) and CSF leakage (3.8%) were the most frequent complications. The mean follow-up period was 43.7 months. The overall survival and progression-free survival rates at 5 years were 76% and 45%, respectively. Recurrent tumor and larger tumor volume (≥ 40 cm3) were identified as risk factors of marginal resection. Patients who presented with recurrent tumor and underwent intralesional resection had a worse long-term outcome.

CONCLUSIONS The classifications of both tumor location and bone invasion demonstrated clinical value. Marginal resection was more likely to be achieved for primary lesions with smaller volumes (< 40 cm3). The rate of CSF leakage declined due to improved dura mater repair with free fat grafts. Marginal resection, or gross-total resection when possible, should be performed in patients with primary chordomas to achieve better long-term survival.

Surgical Treatment of Mesiotemporal Lobe Epilepsy: Which Approach is Favorable?

Neurosurgery 81:992–1004, 2017

Mesiotemporal lobe epilepsy is one of the most frequent causes for pharmacoresistant epilepsy. Different surgical approaches to the mesiotemporal area are used.

OBJECTIVE: To analyze epileptological and neuropsychological results as well as complications of different surgical strategies.

METHODS: This retrospective study is based on a consecutive series of 458 patients all harboring pharmacoresistant mesiotemporal lobe epilepsy. Following procedures were performed: standard anterior temporal lobectomy, anterior temporal or key-hole resection, extended lesionectomy, and transsylvian and subtemporal selective amygdalohippocampectomy. Postoperative outcome was evaluated according to different surgical procedures.

RESULTS: Overall, 1 yr after surgery 315 of 432 patients (72.9%) were classified Engel I; in particular, 72.8% were seizure-free after anterior temporal lobectomy, 76.9% after key-hole resection, 84.4% after extended lesionectomy, 70.3% after transylvian selective amygdalohippocampectomy, and 59.1% after subtemporal selective amygdalohippocampectomy. No significant differences in seizure outcome were found between different resective procedures, neither in short-term nor long-term follow-up. There was no perioperative mortality. Permanent morbidity was encountered in 4.4%. There were no significant differences in complications between different resection types. In the majority of patients, selective attention improved following surgery. Patients after left-sided operations performed significantly worse regarding verbal memory as compared to right-sided procedures. However, surgical approach had no significant effect on memory outcome.

CONCLUSION: Different surgical approaches for mesiotemporal epilepsy analyzed resulted in similar epileptological, neuropsychological results, and complication rates. Therefore, the approach for the individual patient does not only depend on the specific localization of the epileptogenic area, but also on the experience of the surgeon.