Ultrasonic aspiration in neurosurgery: comparative analysis of complications and outcome for three commonly used models

Acta Neurochirurgica (2019) 161:2073–2082

Ultrasonic aspiration (UA) devices are commonly used for resecting intracranial tumors, as they allow for internal debulking of large tumors, hereby avoiding damage to adjacent brain tissue during the dissection. Little is known about their comparative safety profiles.

Methods and materials We analyzed data from a prospective patient registry. Procedures using one of the following UA models were included: Integra® CUSA, Söring®, and Stryker® Sonopet. The primary endpoint was morbidity at discharge, defined as significant worsening on the Karnofsky Performance Scale. Secondary endpoints included morbidity and mortality until 3 months postoperative (M3), occurrence, type, and etiology of complications.

Results Of n = 1028 procedures, the CUSA was used in n = 354 (34.4 %), the Söring in n = 461 (44.8 %), and the Sonopet in n = 213 (20.7 %). There was some heterogeneity of study groups. In multivariable analysis, patients in the Söring (adjusted odds ratio (aOR) 1.29; 95 % confidence interval (CI), 0.80–2.08; p = 0.299), and Sonopet group (aOR, 0.86; 95 % CI, 0.46–1.61; p = 0.645) were as likely as patients in the CUSA group to experience discharge morbidity. At M3, patients in the Söring (aOR, 1.20; 95 % CI, 0.78–1.86; p = 0.415) and Sonopet group (aOR, 0.53; 95 % CI, 0.26–1.08; p = 0.080) were as likely as patients in the CUSA group to experience morbidity. There were also no differences for M3 morbidity in subgroup analyses for gliomas, meningiomas, and metastases. The grade (p = 0.608) and etiology (p = 0.849) of postoperative complications were similar.

Conclusions Neurosurgeons select UA types with regard to certain case-specific characteristics. The safety profiles of three commonly used UA types appear mostly similar.

Short-term versus long-term outcomes of microvascular decompression for hemifacial spasm

Acta Neurochirurgica (2019) 161:2027–2033

Microvascular decompression (MVD) is a useful treatment for hemifacial spasm (HFS), but the postoperative course is extremely diverse. The purpose of this study was to compare short- and long-term outcomes, find the earliest optimal time for determining the long-term outcomes, and investigate the prognostic factors involved in the outcomes over time.

Methods From July 2004 to January 2015, 1341 patients who underwent MVD for HFS were enrolled. Information on clinical features, operative findings, and surgical outcomes over time were collected by performing a review of electronic medical records, and their relationships were analyzed. The outcomes of MVD at 1, 3, 6, and 9 months were individually compared against those at > 12 months after surgery.

Results The mean follow-up period after surgery was 44.9 months (median, 36.8 months; range, 12.0–156.6 months). The overall improvement rate for the 1341 patients was 89.0%. Individual postoperative outcomes at 6 and 9 months showed no differences with those at > 12 months after surgery. Furthermore, in the uni- and multi-variable analyses, patients in whom the offending vessels were intraoperatively determined to be veins showed bad outcomes at 6, 9, and > 12 months (p = 0.048, p = 0.004, and p = 0.003, respectively). Patients with intraoperative indentation on the facial nerve showed good outcomes at 6, 9, and > 12 months (p = 0.005, p = 0.039, and p = 0.020, respectively). Patients with delayed facial palsy after surgery showed better outcomes at 6, 9, and > 12 months (p = 0.002, p = 0.003, and p = 0.028, respectively).

Conclusions Short- and long-term outcomes of MVD in patients with HFS manifested differently, but the outcomes at 6 and 9 months showed similarities with those at > 12 months. In patients in whom the intraoperatively detected offending vessel was not a vein, and in patients with intraoperative indentation on the facial nerve and postoperative delayed facial palsy, good outcomes could be predicted after 6 months of surgery.

Does Drain Position and Duration Influence Outcomes in Patients Undergoing Burr-Hole Evacuation of Chronic Subdural Hematoma?

Neurosurgery, Volume 85, Issue 4, October 2019, Pages 486–493

Drain insertion following chronic subdural hematoma (CSDH) evacuation improves patient outcomes.

OBJECTIVE: To examine whether this is influenced by variation in drain location, positioning or duration of placement.

METHODS: We performed a subgroup analysis of a previously reported multicenter, prospective cohort study of CSDH patients performed between May 2013 and January 2014. Data were analyzed relating drain location (subdural or subgaleal), position (through a frontal or parietal burr hole), and duration of insertion, to outcomes in patients aged >16 yr undergoing burr-hole drainage of primary CSDH. Primary outcomes comprised modified Rankin scale (mRS) at discharge and symptomatic recurrence requiring redrainage within 60 d.

RESULTS: A total of 577 patients were analyzed. The recurrence rate of 6.7% (12/160) in the frontal subdural drain group was comparable to 8.8% (30/343) in the parietal subdural drain group. Only 44/577 (7.6%) patients underwent subgaleal drain insertion. Recurrence rates were comparable between subdural (7.7%; 41/533) and subgaleal (9.1%; 4/44) groups (P = .95). We found no significant differences in discharge mRS between these groups. Recurrence rates were comparable between patients with postoperative drainage for 1 or 2 d, 6.4% and 8.4%, respectively (P = .44). There was no significant difference in mRS scores between these 2 groups (P = .56).

CONCLUSION: Drain insertion after CSDH drainage is important, but position (subgaleal or subdural) and duration did not appear to influence recurrence rate or clinical outcomes. Similarly, drain location did not influence recurrence rate nor outcomes where both parietal and frontal burr holes were made. Further prospective cohort studies or randomized controlled trials could provide further clarification.

Ultra-Early (<12 Hours) Surgery Correlates With Higher Rate of American Spinal Injury Association Impairment Scale Conversion After Cervical Spinal Cord Injury

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 199–203

Cervical spinal cord injury (SCI) is a devastating condition with very few treatment options. It remains unclear if early surgery correlated with conversion of American Spinal Injury Association Impairment Scale (AIS) grade A injuries to higher grades.

OBJECTIVE: To determine the optimal time to surgery after cervical SCI through retrospective analysis.

METHODS: We collected data from 48 patients with cervical SCI. Based on the time from Emergency Department (ED) presentation to surgical decompression, we grouped patients into ultra-early (decompression within 12 h of presentation), early (within 12- 24 h), and late groups (>24 h).We compared the improvement in AIS grade fromadmission to discharge, controlling for confounding factors such as AIS grade on admission, injury severity, and age. The mean time from injury to ED for this group of patients was 17 min.

RESULTS: Patients who received surgery within 12 h after presentation had a relative improvement in AIS grade from admission to discharge: the ultra-early group improved on average 1.3. AIS grades compared to 0.5 in the early group (P = .02). In addition, 88.8% of patients with an AIS grade A converted to a higher grade (AIS B or better) in the ultraearly group, compared to 38.4% in the early and late groups (P= .054).

CONCLUSION: These data suggest that surgical decompression after SCI that takes place within 12 hmay lead to a relative improved neurological recovery compared to surgery that takes place after 12 h.

 

Arachnoiditis as an outcome factor for microvascular decompression in classical trigeminal neuralgia

Acta Neurochirurgica (2019) 161:1589–1598

Neurovascular conflict is considered a key element of classical trigeminal neuralgia (TN) and consequently, mi- crovascular decompression (MVD) is an effective treatment. Nevertheless, failures of MVD are described by many authors. In some patients, the arachnoid membranes surrounding the trigeminal nerve and neighbouring vessels may be thickened and adhesive. Here we analyse the impact of such focal arachnoiditis on outcome after MVD for TN.

Methods A cohort of prospectively followed patients after their MVD was reviewed for intraoperative, imaging and clinical data if findings of arachnoiditis during MVD were described. Long-term outcome assessment was the main endpoint.

Results We reviewed data from 395 MVD procedures, performed for TN from 2001 to 2014. Intraoperative evidence of focal arachnoiditis, as described by the surgeon, has been noted in 51 patients (13%). In 35 (68.6%), neuralgia was typical and in the other 17 (31.4%) it was atypical.
As expected by definition, neurovascular conflict was found in 49 interventions (96%); it was predominantly arterial in 27 (52.9%). Accompanying arachnoiditis was encountered: mild in 20 interventions (39.2%), severe in 31 (60.8%).
A successful result (BNI I or II) was achieved in 29 patients (56.9%). The other 22 patients (43.1%) had persistence or recurrence of pain. Overall KM probability of being pain free at 15 years was 72%.

Conclusions Intraoperative finding of arachnoiditis during MVD for classical trigeminal neuralgia is associated with poorer outcome than that of classical trigeminal neuralgia in general. This is particularly true for low grades of conflict.

Twenty-Five Years of Intracranial Pressure Monitoring After Severe Traumatic Brain Injury: A Retrospective, Single-Center Analysis

Neurosurgery, Volume 85, Issue 1, July 2019, Pages E75–E82

Intracranial pressure (ICP) is a clinically important variable after severe traumatic brain injury (TBI) and has been monitored, along with clinical outcome, for over 25 yr in Addenbrooke’s hospital, Cambridge, United Kingdom. This time period has also seen changes in management strategies with the implementation of protocolled specialist neurocritical care, expansion of neuromonitoring techniques, and adjustments of clinical treatment targets.

OBJECTIVE: To describe the changes in intracranial monitoring variables over the past 25 yr.

METHODS: Data from 1146 TBI patients requiring ICP monitoring were analyzed. Monitored variables included ICP, cerebral perfusion pressure (CPP), and the cerebral pressure reactivity index (PRx). Data were stratified into 5-yr epochs spanning the 25 yr from 1992 to 2017.

RESULTS: CPP increased sharply with specialist neurocritical care management (P < 0.0001) (introduction of a specific TBI management algorithm) before stabilizing from 2000 onwards. ICP decreased significantly over the 25 yr of monitoring from an average of 19 to 12 mmHg (P < 0.0001) but PRx remained unchanged. The mean number of ICP plateau waves and the number of patients developing refractory intracranial hypertension both decreased significantly. Mortality did not significantly change in the cohort (22%).

CONCLUSION: We demonstrate the evolving trends in neurophysiological monitoring over the past 25 yr from a single, academic neurocritical care unit. ICP and CPP were responsive to the introduction of an ICP/CPP protocol while PRx has remained unchanged.

Prevalence of Schizophrenia in Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 84:883–889, 2019

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive and potentially treatable neurodegenerative disease affecting elderly people, characterized by gait impairment and ventricular enlargement in brain imaging. Similar findings are seen in some patients with schizophrenia (SCZ).

OBJECTIVE: To determine the prevalence of SCZ among patients suffering from probable or possible iNPH and the specific effects of comorbid SCZ on the outcome of the cerebrospinal fluid (CSF) shunting.

METHODS: All medical records of the 521 iNPH patients in the NPH registry were retrospectively analyzed from 1991 until 2017. The prevalence of comorbidity of SCZ was determined and compared to that of general aged (≥65 yr) population in Finland.

RESULTS: We identified a total of 16 (3.1%) iNPH patients suffering from comorbid SCZ. The prevalence of SCZ among the iNPH patients was significantly higher compared to the general population (3.1% vs 0.9%, P < .001). All iNPH patients with comorbid SCZ were CSF shunted and 12 (75%) had a clinically verified shunt response 3 to 12mo after the procedure. The CSF shunt response rate did not differ between patients with and without comorbid SCZ.

CONCLUSION: SCZ seems to occur 3 times more frequently among iNPH patients compared to the general aged population in Finland. The outcome of the treatment was not affected by comorbid SCZ and therefore iNPH patients suffering from comorbid SCZ should not be left untreated. These results merit validation in other populations. In addition, further research towards the potential connection between these chronic conditions is warranted.

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.

Surgical outcome in smaller symptomatic vestibular schwannomas. Is there a role for surgery?

Acta Neurochirurgica (2018) 160:2263–2275

Currently, there is no consensus in the initial management of small vestibular schwannomas (VSs). They are routinely watched and/or referred for radiosurgical treatment, although surgical removal is also an option. We hereby evaluate clinical outcomes of patients who have undergone surgical removal of smaller symptomatic VSs.

Methods Patients with vestibular schwannomas (grade T1–T3b according to Hannover classification) were reviewed. Patients with symptomatic tumors who underwent surgery were evaluated. Their preoperative hearing status was based on the guideline of the committee on hearing and equilibriumof the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) foundation. Their postoperative facial nerve function, hearing status, vestibular symptoms, and degree of tumor resection were assessed.

Results Thirty patients were selected for surgery via a retrosigmoid approach based on their age, symptoms, and their own decision-making after discussion of management options. Most patients presented with hearing loss. Seventeen patients had useful hearing preoperatively. Among them, 10 patients (59%) preserved useful hearing (class A or B) postoperatively. MRI at 1-year follow-up confirmed complete resection in 26/29 patients. Also, 29 patients (97%) had HB grade I–II, and 1 patient had HB III at 1-year follow-up. Except for 1 patient with CSF leak, 1 patient with delayed facial nerve palsy, and 2 patients with asymptomatic sigmoid sinus occlusion, there were no other new morbidities.

Conclusion Although both observation and radiosurgery are valid options in the management of smaller size vestibular schwannomas, surgical treatment seems to offer a high rate of facial nerve preservation, a reasonable rate of hearing sparing, and a high total resection rate. Clinicians should consider surgical treatment as a valid option in the initial management of symptomatic small vestibular schwannomas in younger patients.

Long-Term Outcome Following Stereotactic Radiosurgery for Glomus Jugulare Tumors

Neurosurgery 83:1007–1014, 2018

Glomus jugulare tumors (GJTs) are rare benign tumors, which pose significant treatment challenges due to proximity to critical structures.

OBJECTIVE: To evaluate the long-term clinical and radiological outcomein patients undergoing stereotactic radiosurgery (SRS) for GJTs through retrospective study.

METHODS: Forty-two patientswith 43 GJTswere treated using Gamma Knife radiosurgery (GKRS; Elekta AB, Stockholm, Sweden) at our institute from 1997 to 2016. Clinical, imaging, and radiosurgery data were collected from an institutional review board approved database.

RESULTS: Most patients were females (n = 35, 83.3%) and median age was 61 yr (range 23- 88 yr).Median tumor volume and diameterwere 5 cc and 3 cm, respectively,with a median follow-up of 62.3 mo (3.4-218.6 mo). Overall, 20 patients (47.6%) improved clinically and 14 (33.3%) remained unchanged at last follow-up. New onset or worsening of hearing loss was noted in 6 patients (17.2%) after SRS. The median prescription dose to the tumor margin was 15 Gy (12-18 Gy). Median reduction in tumor volume and maximum tumor diameter at last follow-up was 33.3% and 11.54%, respectively. The 5-yr and 10-yr tumor control rates were 87%±6% and 69%±13%, respectively. There was no correlation between maximum or mean dose to the internal acoustic canal and post-GK hearing loss (P > .05).

CONCLUSION: SRS is safe and effective in patients with GJTs and results in durable, longterm control. SRS has lower morbidity than that associated with surgical resection, particularly lower cranial nerve dysfunction, and can be a first-line management option in these patients.

Favorable clinical outcome following surgical evacuation of deep-seated and lobar supratentorial intracerebral hemorrhage

Acta Neurochirurgica (2018) 160:1737–1747

In spontaneous supratentorial intracerebral hemorrhage (ICH), the role of surgical treatment remains controversial, particularly in deep-seated ICHs. We hypothesized that early mortality and long-term functional outcome differ between patients with surgically treated lobar and deep-seated ICH.

Method Patients who underwent craniotomy for ICH evacuation from 2009 to 2015 were retrospectively evaluated and categorized into two subgroups: lobar and deep-seated ICH. The modified Rankin Scale (mRS) was used to evaluate long-term functional outcome.

Result Of the 123 patients operated for ICH, 49.6%(n = 61) had lobar and 50.4%(n = 62) deep-seated ICH. At long-term followup (mean 4.2 years), 25 patients (20.3%) were dead, while 51.0% of survivors had a favorable outcome (mRS score ≤ 3). Overall mortality was 13.0% at 30 days and 17.9% at 6 months post-ictus, not influenced by ICH location. Mortality was higher in patients ≥ 65 years old (p = 0.020). The deep-seated group had higher incidence and extent of intraventricular extension, younger age (52.6 ± 9.0 years vs. 58.5 ± 9.8 years; p < 0.05), more frequently pupillary abnormalities, and longer neurocritical care stay (p < 0.05). The proportion of patients with good outcome was 48.0% in deep-seated vs. 54.1% in lobar ICH (p = 0.552). In lobar ICH, independent predictors of long-term outcome were age, hemorrhage volume, preoperative level of consciousness, and pupillary reaction. In deep-seated ICHs, only high age correlated significantly with poor outcome.

Conclusions At long-term follow-up, most ICH survivors had a favorable clinical outcome. Neither mortality nor long-term functional outcome differed between patients operated for lobar or deep-seated ICH. A combination of surgery and neurocritical care can result in favorable clinical outcome, regardless of ICH location.

 

Cranial Chordoma: A New Preoperative Grading System

Neurosurgery 83:403–415, 2018

Chordomas are rare but challenging neoplasms involving the skull base. A preoperative grading system will be useful to identify both areas for treatment and risk factors, and correlate to the degree of resection, complications, and recurrence.

OBJECTIVE: To propose a new grading system for cranial chordomas designed by the senior author. Its purpose is to enable comparison of different tumors with a similar pathology to clivus chordoma, and statistically correlate with postoperative outcomes.

METHODS: The numerical grading system included tumor size, site of the tumor, vascular encasement, intradural extension, brainstem invasion, and recurrence of the tumor either after surgery or radiotherapy with a range of 2 to 25 points; it was used in 42 patients with cranial chordoma. The grading system was correlated with number of operations for resection, degree of resection, number and type of complications, recurrence, and survival.

RESULTS: We found 3 groups: low-risk 0 to 7 points, intermediate-risk 8 to 12 points, and high-risk≥13 points in the grading system. The 3 groupswere correlated with the following: extent of resection (partial, subtotal, or complete; P < .002); number of operative stages to achieve removal (P < .014); tumor recurrence (P = .03); postoperative Karnofsky Performance Status (P < .001); and with successful outcome (P = .005). The grading system itself correlated with the outcome (P = .005).

CONCLUSION: The proposed chordoma grading system can help surgeons to predict the difficulty of the case and know which areas of the skull base will need attention to plan further therapy.

Simple Preoperative Patient-Reported Factors Predict Adverse Outcome After Elective Cranial Neurosurgery

Neurosurgery, 83, 2: 197–202

Patient-reported preoperative factors hold promise in improving the prediction of postoperative adverse events, but they have been poorly studied.
OBJECTIVE
To study the role of patient-reported factors in the preoperative risk stratification of elective craniotomy patients.
METHODS
A prospective, unselected cohort of 322 adult patients underwent elective craniotomy in Helsinki, Finland. We preoperatively recorded the American Society of Anesthesiologists (ASA) score, Helsinki ASA score, and 3 questionnaire-based patient-reported factors including overall health status, ability to climb 2 flights of stairs, and cognitive function (Test Your Memory test). Outcome measures comprised in-hospital major and overall morbidity. Receiver-operating characteristic curves served to calculate area under the curve (AUC) values for a composite score of patient-reported factors and both ASA scores with regard to outcomes.
RESULTS
In-hospital major and overall morbidity rate was 15.2%. Only preoperatively diminished cognitive function remained a significant predictor of major morbidity after multivariable logistic regression analysis (P < .001, odds ratio 1.1, confidence interval 1.0-1.1). A composite score of our 3 patient-reported factors had a higher AUC (0.675) for major morbidity than original ASA score (0.543) or Helsinki ASA score (0.572). In elderly patients, the composite score had an AUC of 0.726 for major morbidity.
CONCLUSION
Preoperative patient-reported factors had higher sensitivity for detecting major morbidity compared to the ASA scores in this study. Particularly, the simple composite score seems to predict adverse outcomes in elective cranial surgery surprisingly well, especially in the elderly. These results are interesting and worth confirming in other centers.

Prognostic Factors for Satisfaction After Decompression Surgery for Lumbar Spinal Stenosis

Neurosurgery 82:645–651, 2018

Surgical treatment for lumbar spinal stenosis is associated with both short- and long-term benefits with improvements in patient function and pain. Even though most patients are satisfied postoperatively, some studies report that up to onethird of patients are dissatisfied.

OBJECTIVE: To present clinical outcome data and identify prognostic factors related to patient satisfaction 1 yr after posterior decompression surgery for lumbar spinal stenosis.

METHODS: This multicenter register study included 2562 patients. Patients were treated with various types of posterior decompression. Patients with previous spine surgery or concomitant fusion were excluded. Patient satisfaction was analyzed for associations with age, sex, body mass index, smoking status, duration of pain, number of decompressed vertebral levels, comorbidities, and patient-reported outcome measures,which were used to quantify the effect of the surgical intervention.

RESULTS: At 1-yr follow-up, 62.4% of patients were satisfied but 15.1% reported dissatisfaction. The satisfied patients showed significantly greater improvement in all outcome measures compared to the dissatisfied patients. The outcome scores for the dissatisfied patients were relatively unchanged or worse compared to baseline. Association was seen between dissatisfaction, duration of leg pain, smoking status, and patient comorbidities. Patients with good walking capacity at baseline were less prone to be dissatisfied compared to patients with poor walking capacity.

CONCLUSION: This study found smoking, long duration of leg pain, and cancerous and neurological disease to be associated with patient dissatisfaction, whereas good walking capacity at baseline was positively associated with satisfaction after 1 yr.

Endplate changes after lumbar discectomy with and without implantation of an annular closure device

Acta Neurochirurgica (2018) 160:855–862

The implantation of a bone-anchored annular closure device (ACD) might be associated with the developed new endplate changes (EPC) after surgery.

Methods A post hoc analysis has been done in patients from a prospective randomized multicenter study. All patients underwent limited lumbar discectomy with intraoperative randomization into the groups limited lumbar discectomy alone or additional ACD implantation. Low-dose lumbar computed tomography (CT) and clinical investigations were performed preoperatively and 12 months after the operation.

Results A total of 554 patients were randomized. After exclusion of dropouts, the per-protocol population included 493 patients (251 in the control group and 242 in the ACD group); the follow-up rate was ≥ 90%. The number of patients showing EPC at baseline was similar in both groups. The number of patients showing EPC and the total EPC lesion area significantly increased in both groups over time, but significantly increased more in the EPC group for the superior and inferior endplate (all P < 0.0001). There was no association of pre-existing number and size of EPC with sex, age, or smoking habits. Correlation of clinical variables showed no relation with number, size, and increase of EPC area after surgery.

Conclusions Patients with primary lumbar disc herniation show EPC in the corresponding segments. There is a significant increase of lesion number and size within 12 months after discectomy. This increase is significantly more pronounced in the ACD group. Presence and growth of EPC is not correlated with low-back pain or ODI.

Brainstem arteriovenous malformations: lesion characteristics and treatment outcomes

J Neurosurg 128:126–136, 2018

Brainstem arteriovenous malformations (AVMs) are rare lesions that are difficult to diagnose and treat. They are often more aggressive in their behavior when compared with their supratentorial counterparts. The consequence of a brainstem hemorrhage is often devastating, and many patients are in poor neurological status at presentation. The authors examine the factors associated with angiographically confirmed cure and those affecting management outcomes for these complex lesions.

METHODS This was a retrospective analysis of data gathered from the prospectively maintained Stanford AVM database. Lesions were grouped based on their location in the brainstem (medulla, pons, or midbrain) and the quadrant they occupied. Angiographic cure was dichotomized as completely obliterated or not, and functional outcome was dichotomized as either independent or not independent at last follow-up.

RESULTS Over a 23-year period, 39 lesions were treated. Of these, 3 were located in the medulla, 14 in the pons, and 22 in the midbrain. At presentation, 92% of the patients had hemorrhage, and only 43.6% were functionally independent. Surgery resulted in the best radiographic cure rates, with a morbidity rate of 12.5%. In all, 53% of patients either improved or remained stable after surgery. Absence of residual nidus and female sex correlated with better outcomes.

CONCLUSIONS Brainstem AVMs usually present with hemorrhage. Surgery offers the best chance of cure, either in isolation or in combination with other modalities as appropriate.

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

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.

Stereotactic Radiosurgery for Brainstem Arteriovenous Malformations

Neurosurgery 81:910–920, 2017

The management of brainstem arteriovenous malformations (bAVMs) is a formidable challenge. bAVMs harbor higher morbidity and mortality compared to other locations.

OBJECTIVE: To review the outcomes following stereotactic radiosurgery (SRS) of bAVMs in a multicenter study.

METHODS: Six medical centers contributed data from 205 patients through the International Gamma Knife Research Foundation. Median age was 32 yr (6-81). Median nidus volume was 1.4 mL (0.1-69 mL). Favorable outcome (FO) was defined as AVM obliteration and no post-treatment hemorrhage or permanent symptomatic radiation-induced complications.

RESULTS: Overall obliteration was reported in 65.4% (n = 134) at a mean follow-up of 69 mo. Obliteration was angiographically proven in 53.2% (n = 109) and on MRA in 12.2% (n=25). Actuarial rate of obliteration at 2, 3, 5, 7, and 10 yr after SRS was 24.5%, 43.3%, 62.3%, 73%, and 81.8% respectively. Patients treated with a margin dose >20 Gy were more likely to achieve obliteration (P = .001). Obliteration occurred earlier in patients who received a higher prescribed margin dose (P = .05) and maximum dose (P = .041). Post-SRS hemorrhage occurred in 8.8% (n = 18). Annual post gamma knife latency period hemorrhage was 1.5%. Radiation-induced complications were radiologically evident in 35.6% (n = 73), symptomatic in 14.6% (n=30), and permanent in 14.6% (n=30, which included long-tract signs and new cranial nerve deficits). FO was achieved in 64.4% (n = 132). Predictors of an FO were a higher Virginia radiosurgery AVM scale score (P = .003), prior hemorrhage (P = .045), and a lower prescribed maximum dose (P = .006).

CONCLUSION: SRS for bAVMs results in obliteration and avoids permanent complications in the majority of patients.