Neurosurgery Blog

28/01/201527/01/2015

Reconstruction of the anterior skull base after major trauma or extensive tumour resection

Acta Neurochir (2015) 157:139–144

The authors describe their experience with the reconstruction of complex anterior skull base defects after trauma or tumour resection using a “sandwich” technique with pericranial flap, titanium mesh and TachoSil.

Methods Description of surgical anatomy, surgical technique, indications, limitations, complications, specific perioperative considerations and specific information to give to the patient about surgery and potential risks. A summary of ten key points is given.

Conclusions After a bifrontal craniotomy and a subfrontal approach, it is possible to achieve a reliable reconstruction of the anterior skull base in a watertight manner by fixing a pericranial flap or a fascia lata graft to the orbital roofs and planum sphenoidale with an individually tailored titanium mesh and closing the frontobasal dura lesion with TachoSil.

27/01/201524/01/2015

Gamma Knife radiosurgery for meningiomas arising from the tentorium

J Neurooncol (2015) 121:129–134

In order to evaluate long term clinical and imaging outcomes, the authors retrospectively reviewed our 22-year experience using stereotactic radiosurgery (SRS) for tentorial meningiomas.

Thirty-nine patients with tentorial meningiomas underwent SRS using various Gamma Knife technologies between 1988 and 2010. The most common presenting symptoms were headache, dizziness or disequilibrium, and ataxia. The median tumor volume was 4.6 cm3 (range 0.5–36.6 cm3) and the median radiation dose to the tumor margin was 14 Gy (range 8.9–18 Gy). The median follow-up period was 41 months (range 6–183 months).

At the last imaging follow-up, tumor volumes decreased in 22 patients (57 %), remained stable in 13 patients (33 %), and increased in 4 patients (10 %). The progression-free survival after SRS was 97 % at 1 year, and 92 % at 5 years. At the last clinical followup, 35 patients (90 %) showed no change in symptoms, 1 patient (2 %) showed improvement of their neurologic symptom, and 3 patients (8 %) demonstrated worsening symptoms. The rate of symptom worsening after SRS was 5 % at 1 year, and 10 % at 5 years. Asymptomatic peritumoral edema after SRS occurred in 2 patients (5 %). Symptomatic adverse radiation effect developed in 2 patients (5 %).

SRS for tentorial meningiomas provided long-term effective tumor control and a low risk of radiation related complications.

26/01/201524/01/2015

Syrinx resolution is correlated with the upward shifting of cerebellar tonsil following posterior fossa decompression in pediatric patients with Chiari malformation type I

Eur Spine J (2015) 24:155–161

Chiari malformation type I (CMI) is characterized by deformed hindbrain. This study aimed to quantitatively evaluate the alterations in position of hindbrain after Posterior fossa decompression (PFD), and to identify the factors associated with syrinx resolution in pediatric patients with CMI.

Methods Eighty-seven patients, aged from 5 to 18 years, who underwent PFD for CMI between September 2006 and September 2012 were retrospectively reviewed. On midsagittal MR images, the position of medulla oblongata and cerebellum was quantitatively evaluated preoperatively and at follow-up. The maximal syrinx/cord (S/C) ratio and syrinx length were also measured. Significant improvement of syrinx was defined as a more than 20 % decrease in maximal S/C ratio or length on follow-up MRI.

Results Neurological deficits were found in 51 of the 87 patients preoperatively and 37 (72.4 %) of them obtained improvement of their symptoms at the last visit. Overall, upward shifting of the tip of cerebellar tonsil was observed in 66 (75.9 %) patients at the last follow-up. Moreover, the mean longitudinal distance of the tip of cerebellar tonsil changed from 16.47 ± 5.00 to 13.89 ± 4.38 mm (P<0.001) at final follow-up. Significant syrinx resolution was noticed in 79 (90.8 %) cases. Pointed cerebellar tonsils were found in 85 (97.7 %) of our patients preoperatively and 78 (91.8 %) of them acquired round cerebellar tonsils after PFD. The improvement of maximal S/C ratio was significantly correlated with upward shifting of the tip of cerebellar tonsil (P = 0.023).

Conclusions Following PFD for CMI, position and morphology of the cerebellar tonsil could revert to normal in most of the pediatric patients, and the upward shifting of the tip of cerebellar tonsil is significantly correlated with syrinx improvement. From this study, PFD without shunting may be effective for syrinx secondary to CMI in pediatric population.

23/01/201522/01/2015

Endovascular Treatment of 346 Middle Cerebral Artery Aneurysms

Neurosurgery 76:54–61, 2015

The endovascular treatment of middle cerebral artery (MCA) aneurysms has been controversial because of the frequency of complex anatomy and the relative ease of surgical clipping in this location.

OBJECTIVE: To present a large single-center experience with the endovascular treatment of MCA aneurysms.

METHODS: The neurointerventional database at our institution was reviewed for all endovascular treatments of MCA aneurysms. Demographics, aneurysm characteristics, treatment modality, intraprocedural hemorrhagic and thromboembolic events, 30-day neurological events, and follow-up angiographic studies were recorded.

RESULTS: From December 1996 to April 2013, 292 patients underwent endovascular treatment of 346 MCA aneurysms. Of these, 341 (98.6%) were successfully completed. Balloon neck remodeling was used in 230 procedures (66.5%). Ninety-five procedures (27.4%) were for ruptured aneurysms. The rate of intraprocedural hemorrhage was 2.6% (9 of 346). The overall rate of intraprocedural thromboembolic events was 13.6% (47 of 346), significantly more common in patients with acute subarachnoid hemorrhage (27.4%; P, .001). The 30-day major (modified Rankin Scale score . 2) neurological event rate was 2.9% (10 of 346), significantly more common in patients with subarachnoid hemorrhage (8.4%) compared with those without (0.8%; P , .001). The rate of complete or near-complete aneurysm occlusion at was 90.6% $ 6 months and 91.8% at $ 2 years, with an average of 24 months of follow-up available for 247 procedures.

CONCLUSION: Endovascular treatment of MCA aneurysms can be safe and effective. However, it is associated with a high asymptomatic thromboembolic event rate that is more frequent in the setting of acute subarachnoid hemorrhage.

KEY WORDS:

22/01/201521/01/2015

Extended endoscopic transsphenoidal approach infrachiasmatic corridor

$EE transsphenoidal approach infrachiasmatic corridor$

Neurosurg Rev (2015) 38:137–147

An extended endoscopic transsphenoidal approach is required for skull base lesions extending to the suprasellar area. Inferior approach using the infrachiasmatic corridor allows access to the lesions through the tumor growth that is favorable for the extended transsphenoidal approaches. Infrachiasmatic corridor is a safer route for the inferior approaches that is made up by basal arachnoid membrane and Liliequist’s membrane with its leaves (diencephalic and mesencephalic leaf). This area extends from the optic canal and tuberculum sella to the corpus mamillare.

We performed extended endoscopic approach using the infrachiasmatic corridor in 52 cases, including tuberculum sella meningiomas (n:23), craniopharyngiomas (n:16), suprasellar Rathke’s cleft cyst (n:6), pituitary adenoma (n:2), fibrous dysplasia (n:1), infundibular granulosa cell tumor (n:2), and epidermoid tumor (n:2). Total resection was achieved in 17 of 23 (74 %) with tuberculum sellae meningioma using infrachiasmatic approach. Twenty patients presented with visual disorders and 14 of them improved. There were two postoperative cerebrospinal fluid (CSF) leakages and one transient diabetes insipidus and one permanent diabetes insipidus. Sixteen patients were operated on by the infrachiasmatic approach for craniopharyngiomas. Improvement was reached in seven of eight patients presented with visual disorders. Complete tumor resection was performed in 10 of 16 cases and cyst aspiration in 4 cases, and there were remnants in two cases. Postoperative CSF leakage was seen in two patients.

Infrachiasmatic corridor provides an easier and safer inferior route for the removal of middle midline skull base lesions in selected cases.

21/01/201519/01/2015

Effect of postural changes on ICP in healthy and ill subjects

Acta Neurochir (2015) 157:109–113

Reference values and physiological measurements of intracranial pressure (ICP) are primarily reported in the supine position, while reports of ICP in the vertical position are surprisingly rare considering that humans maintain the vertical position for the majority of the day. In order to distinguish normal human physiology from disease entities such as idiopathic intracranial hypertension and normal pressure hydrocephalus, we investigated ICP in different body postures in both normal and ill subjects.

Methods Thirty-one patients were included: four normal patients following complete removal of a solitary clearly demarcated small brain tumour and fitted with a telemetric ICP monitoring device for long-term ICP monitoring; 27 patients requiring invasive ICP monitoring as a part of their diagnostic work-up or monitoring of shunt treatment effect. ICP was recorded in the following body positions: upright standing, sitting in a chair, supine and right lateral lumbar puncture position.

Results Linear regression of median ICP based on patient posture, group, and purpose of monitoring presented a significant model (p<0.001), but could not distinguish between patient groups (p=0.88). Regression of differences in median ICP between body postures and supine ICP as the baseline, presented a highly significant model (p<0.001) and adjusted R2=0.86. Both body posture (p<0.001) and patient group (p<0.001) were highly significant factors.

Conclusions Differences in ICP between body postures enabled us to distinguish the normal group from patient groups. Normal patients appear able to more tightly regulate ICP when switching body postures.

20/01/201519/01/2015

Management of complex intracranial aneurysms with bypass surgery

Neurosurg Rev (2015) 38:109–120

Despite advances in microsurgery and the development of new endovascular techniques, the treatment of complex intracranial aneurysms remains a daunting challenge for neurosurgeons. In the present study, we retrospectively reviewed our experience of bypass surgery in the treatment of 93 cases of complex intracranial aneurysms.

A series of 93 consecutive cases of complex intracranial aneurysms were treated with bypass surgery between April 2004 and July 2013. Radial artery (RA) grafts were used in 58 cases, saphenous vein (SV) grafts in 16 cases, and occipital artery (OA) grafts in 6 cases, while the remaining 13 cases were managed with superficial temporal artery (STA) grafts. In this series, the aneurysms were excised after trapping in 32 cases with mass effect and neural compression. Proximal occlusion of the parent artery was performed in 22 cases of fusiform or giant dissecting aneurysms with subsequent retrograde flow to avoid compromise of the perforators nearby. Trapping was performed after bypass surgery in the remaining 39 cases. Postoperative angiographies were performed in 91 patients and patency of the bypass graft and obliteration of the aneurysms were confirmed in 89 patients. Patency of the bypass could not be confirmed in the remaining two patients, of which one presented with cerebral infarction due to graft occlusion, and the other remained asymptomatic. Within 1 month after surgery, 88 patients had good outcome, four patients needed assistance for daily living, and one death occurred due to brainstem infarction. In 77 patients with a mean follow-up of 3.0 years, 72 patients had good outcome, 4 patients needed assistance for daily living, and 1 death occurred unrelated to surgery.

Complex intracranial aneurysms present unique therapeutic challenges that require thorough surgical planning, individualized treatment strategies, and refined neurovascular techniques for successful outcome. Proper use of bypass surgery is imperative in preserving the parent artery and its major perforators. The internal maxillary artery, used as a donor in a bypass, is an effective method due to its shorter distance from the recipient vessels and relatively large diameter with resulting higher flow rate.

19/01/201518/01/2015

Anterior cervical discectomy versus corpectomy for multilevel cervical spondylotic myelopathy: a meta-analysis

Eur Spine J (2015) 24:31–39

This is a meta-analysis to compare the results between anterior cervical discectomy fusion (ACDF) and anterior cervical corpectomy fusion (ACCF) for the patients with multilevel cervical spondylotic myelopathy (MCSM).

Methods Systematic review and meta-analysis of cohort studies between ACDF with plate fixation and ACCF with plate fixation for the treatment of MCSM. An extensive search of literature was performed in PubMed, Mediline, Embase and the Cochrane library. The following outcome measures were extracted: JOA scores, fusion rate, cervical lordosis (C2–7), complications, blood loss and operation time. Data analysis was conducted with RevMan 5.0.

Results Four cohorts (six studies) involving 258 patients were included in this study. The pooled analysis showed that there was no significant difference in the postoperative JOA score [WMD = -0.14 (-1.37, 1.10), P = 0.83], fusion rate [OR = 0.84 (0.15, 4.86), P = 0.85] between two group. However, there was significant difference in the cervical lordosis [WMD = 3.38 (2.52, 4.23), P<0.00001], surgical complication rate and instrument related complication rate (P = 0.01, 0.005 respectively), blood loss [WMD = -52.53 (-73.53, -31.52), P<0.00001], and operation time [WMD = -14.10 (-20.27, -7.93), P<0.00001].

Conclusions As compared with ACCF with plate fixation, ACDF with plate fixation showed no significant differences in terms of postoperative JOA score, fusion rate, but better improved cervical lordosis, lower complication and smaller surgical trauma. As the limitations of small sample and short follow-up in this study, it still could not be identified whether ACDF with plate fixation is more effective and safer than ACCF with plate fixation.

16/01/201514/01/2015

Long-term Results of Endonasal Endoscopic Transsphenoidal Resection of Nonfunctioning Pituitary Macroadenomas

Neurosurgery 76:42–53, 2015

Several studies report early results of endoscopic endonasal transsphenoidal surgery; however, none discuss long-term outcome measures such as tumor recurrence rates and the need for additional surgical procedures.

OBJECTIVE: To discuss the long-term outcomes after endoscopic endonasal transsphenoidal surgery for nonfunctioning pituitary macroadenomas.

METHODS: This is a retrospective study. Patients were included only if they had at least 5 years of clinical and imaging follow-up after surgery.

RESULTS: Eighty patients met the study criteria. Grossly complete resection was achieved in 71% of patients. Knosp grade 0 to 2 tumors and tumor with volumes ,10 cm3 were significantly more likely to have received a grossly complete resection. There were 7 recurrences (12%) in patients who had received grossly complete resections, with a mean time to recurrence of 53 months. Among the 23 patients who had subtotal resections, 11 (61%) progressed radiographically, and 3 (17%) had symptomatic progression. Knosp score, surgical and radiographic evidence of invasion, and preoperative visual deficits were predictive of recurrence in a univariate analysis, but Knosp grade was the only independent predictor in a multivariate analysis. Kaplan-Meier analysis projected a 10-year progression-free survival rate of 80% and 21% for patients with gross total resections and subtotal resections, respectively.

CONCLUSION: At the long-term follow-up, 12% of patients had recurrent tumors after grossly complete resection. Recurrent or residual tumors were treated with either repeat surgery or Gamma Knife radiosurgery. Rates of complete resection, postoperative surgical and endocrinological complications, and additional surgical procedures are similar to previously published reports after microscopic transsphenoidal surgery.

15/01/201514/01/2015

The immediately failed lumbar disc surgery

Neurosurg Rev (2015) 38:191–195

Studies on immediate failed back surgery syndrome (iFBSS) following lumbar microdiscectomy are rare. Our aim is to describe the incidence and the causes of these immediate failures to define the value of radiological imaging for identification of the underlying pathology and to propose a management algorithm.

We defined iFBSS as persistence, deterioration or recurrence (during hospital stay) of radicular pain and/or sensorimotor deficits and/or sphincter dysfunction after microdiscectomy, which was uneventful from the surgeon’s perspective.

The medical records of 1546 patients undergoing discectomy for mediolateral lumbar disc herniations were screened for iFBSS. The pre- and postoperative imaging, surgical records, therapy and outcome of patients with iFBSS were reviewed. Forty-four of 1546 patients (2.8 %) with iFBSS were identified. All patients underwent reoperation. Overseen disc material/re-herniation (n=22), epidural hematoma (n=6), inadequate decompression of accompanying recessal stenosis (n=2) and dural tear with fascicle herniation (n=1) were found to be causative. In 13 patients, who revealed no clear pathology intraoperatively, we diagnosed a battered root syndrome (nerve root swelling due to excessive surgical manipulation). The correct diagnosis could be established by neuroradiological imaging in 25 of 43 radiologically investigated patients (57 %). In our study, the radiological workup was of limited value for the correct differentiation of the various aetiologies of iFBSS.

Therefore, the authors believe that the treatment strategy should strongly rely on the clinical presentation. To avoid unnecessary surgery in cases of battered root syndrome, we propose to proceed to reoperation only in patients with new or persistent radiculopathy despite adequate antiedematous medical therapy.

14/01/201514/01/2015

Delayed relief of hemifacial spasm after microvascular decompression

Acta Neurochir (2015) 157:93–99

Although microvascular decompression (MVD) surgery has been widely accepted as an effective treatment for hemifacial spasm (HFS), delayed relief cases have been frequently reported. Therefore, the value of an immediate redo MVD should be discussed.

Methods This study included 1,435 HFS patients who underwent MVD with intraoperative abnormal muscle response (AMR) monitoring from 2011 through 2013 at XinHua Hospital. These cases were analyzed retrospectively with emphasis on the postoperative outcomes and introaperative findings.

Results After MVD, 1,384 HFS patients obtained relief immediately. The 51 unrelieved patients underwent AMR monitoring again the next day; this was positive in 48 and negative in 3 patients. These three patients with negative AMR obtained relief spontaneously within a week. Among the 48 positive patients, 31 and 11 were underwent redoMVD within a week and 5–22 months, respectively, and all achieved relief after the second operation. Of the six remainig patients, two obtained relief within 2months and 4 remained unchanged in the up-to- 3-year’s follow-up period. In redoMVDs, insufficient decompression of the facial nerve accounted for the failure. Finally, in this database, the immediate postoperative cure rate was 96.4 %; with earlier redo MVD, the final cure rate could be increased to 99.9 %.

Conclusions Despite being a reasonable remedy for HFS in the hands of an experienced neurosurgeon, sometimes small vessels can be missed while managing the main offending arteries during MVDs, which might account for the delayed relief. Therefore, reexamination of the AMR is necessary for unimproved patients; if a positive result is recorded, an immediate redo MVD is suggested.

13/01/201520/04/2020

New insights in the limbic modulation of visual inputs: The role of the inferior longitudinal fasciculus and the Li-Am bundle

Neurosurg Rev (2015) 38:179–190

Recent anatomical and DTI data demonstrated new aspects in the subcortical occipito-temporal connections. Although a direct (inferior longitudinal fasciculus, ILF) pathway has been previously described, its fine description is still matter of debate. Moreover, a fast and direct subcortical connection between the limbic system and the occipital lobe has been previously recognized in many functional studies but it still remains poorly documented by anatomical images. We provided for the first time an extensive and detailed anatomical description of the ILF subcortical segmentation.

We dissected four human hemispheres with modified Klingler’s technique, from the basal to the lateral occipito-temporal surface in the two steps, tracking the ILF fibers until their cortical termination. Pictures of this direct temporo-occipital pathway are discussed in the light of recent literature regarding anatomy and functions of occipito-temporal areas.

The dissection confirmed the classical originating branches of ILF and allowed a fine description of two main subcomponent of this bundle, both characterized by separate hierarchical distribution: a dorsal ILF and a ventral ILF. Moreover, a direct pathway between lingual cortex and amygdala, not previously demonstrated, is here described with anatomical images. Even if preliminary in results, this is the first fine description of ILF’s subcomponents.

The complex but clearly segregated organization of the fibers of this bundle (dILF and vILF) supports different level of functions mediated by visual recognition. Moreover, the newly described direct pathway from lingual to amygdala (Li-Am), seems involved in the limbic modulation of visual processing, so it may support physiological conditions the crucial role of this connection in human social cognition. In pathological conditions, on the other hand, this may be one of the hyperactivated pathways in temporooccipital epileptic and nonepileptic syndromes.

12/01/201511/01/2015

Validation of the Supplemented Spetzler-Martin Grading System for Brain Arteriovenous Malformations in a Multicenter Cohort of 1009 Surgical Patients

Neurosurgery 76:25–33, 2015

The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients.

OBJECTIVE: To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone.

METHODS: Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers.

RESULTS: In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P , .001). Stratified analysis fitting models within 3 different follow-up groupings (,6 months, 6 months-2 years, and .2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SMSupp grades #6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades .6 (39%-63%).

CONCLUSION: This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of 6 is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

09/01/201508/01/2015

Indocyanine green videoangiography methodological variations: review

Neurosurg Rev (2015) 38:49–57

Indocyanine green videoangiography (ICGVA) procedures have become widespread within the spectrum of microsurgical techniques for neurovascular pathologies.

We have conducted a review to identify and assess the impact of all of the methodological variations of conventional ICGVA applied in the field of neurovascular pathology that have been published to date in the English literature.

A total of 18 studies were included in this review, identifying four primary methodological variants compared to conventional ICGVA: techniques based on the transient occlusion, intra-arterial ICG administration via catheters, use of endoscope system with a filter to collect fluorescence of ICG, and quantitative fluorescence analysis. These variants offer some possibilities for resolving the limitations of the conventional technique (first, the vascular structure to be analyzed must be exposed and second, vascular filling with ICG follows an additive pattern) and allow qualitatively superior information to be obtained during surgery. Advantages and disadvantages of each procedure are discussed.

More case studies with a greater number of patients are needed to compare the different procedures with their gold standard, in order to establish these results consistently.

08/01/201506/01/2015

Traumatic Brain Injuries: The Influence of the Direction of Impact

Neurosurgery 76:81–91, 2015

Head impact direction has been identified as an influential risk factor in the risk of traumatic brain injury (TBI) from animal and anatomic research; however, to date, there has been little investigation into this relationship in human subjects. If a susceptibility to certain types of TBI based on impact direction was found to exist in humans, it would aid in clinical diagnoses as well as prevention methods for these types of injuries.

OBJECTIVE: To examine the influence of impact direction on the presence of TBI lesions, specifically, subdural hematomas, subarachnoid hemorrhage, and parenchymal contusions.

METHODS: Twenty reconstructions of falls that resulted in a TBI were conducted in a laboratory based on eyewitness, interview, and medical reports. The reconstructions involved impacts to a Hybrid III anthropometric dummy and finite element modeling of the human head to evaluate the brain stresses and strains for each TBI event.

RESULTS: The results showed that it is likely that increased risk of incurring a subdural hematoma exists from impacts to the frontal or occipital regions, and parenchymal contusions from impacts to the side of the head. There was no definitive link between impact direction and subarachnoid hemorrhage. In addition, the results indicate that there is a continuum of stresses and strain magnitudes between lesion types when impact location is isolated, with subdural hematoma occurring at lower magnitudes for frontal and occipital region impacts, and contusions lower for impacts to the side.

CONCLUSION: This hospital data set suggests that there is an effect that impact direction has on TBI depending on the anatomy involved for each particular lesion.

07/01/201506/01/2015

Influence of cumulative surgical experience on the outcome of poor-grade patients with ruptured intracranial aneurysm

Acta Neurochir (2015) 157:1–7

The expansion of endovascular techniques for intracranial aneurysms has led to a global decrease in vascular neurosurgery activity. This situation might impact neurosurgeons’ level of expertise, even though they all might have to deal with this surgically challenging pathology. In that context, we wanted to assess the impact of cumulative surgical experience on the outcome of patients with poor-grade subarachnoid haemorrhage (SAH) and intracerebral haemorrhage (ICH) treated by microsurgery.

Methods Sixty-seven patients who underwent surgery for a ruptured aneurysm with SAH and ICH, and a WFNS scale of IV/V, were included. Surgeries were performed by five surgeons, whose experience was judged by the total number of aneurysm surgeries performed. The outcome was assessed by three indicators: intraoperative rupture (IOR), early mortality, and the modified Rankin Scale at last follow-up. The time of IOR was reported on an IOR score. The correlation between surgical experience and outcome was assessed by linear regression. Nonlinear regression was used to assess the correlation of the data with a learning curve model.

Results The analysis showed an influence of surgical experience on intraoperative rupture, with no effect on long-term outcome. No influence was found on early mortality. Increased surgical experience seems to reduce IOR during aneurysm dissection and clip repositioning. Intraoperative rupture data fit Wright’s learning curve model.

Conclusion This study suggests a direct impact of cumulative experience on the course of ruptured aneurysm surgery and pleads for the use of training and simulation programmes dedicated to neurovascular surgery.

06/01/201504/01/2015

Outcomes of Anterior Lumbar Interbody Fusion Surgery Based on Indication: A Prospective Study

Neurosurgery 76:7–24, 2015

There is limited information on clinical outcomes after anterior lumbar interbody fusion (ALIF) based on the indications for surgery.

OBJECTIVE: To compare the clinical and radiological outcomes of ALIF for each surgical indication.

METHODS: This prospective clinical study included 125 patients who underwent ALIF over a 2-year period. The patients were evaluated preoperatively and postoperatively. Outcome measures included the Short Form-12, Oswestry Disability Index, Visual Analog Scale, and Patient Satisfaction Index.

RESULTS: After a mean follow-up of 20 months, the clinical condition of the patients was significantly better than their preoperative status across all indications. A total of 108 patients had a Patient Satisfaction Index score of 1 or 2, indicating a successful clinical outcome in 86%. Patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and scoliosis had the best clinical response to ALIF, with statistically significant improvement in the Short Form-12, Oswestry Disability Index, and Visual Analog Scale. Failed posterior fusion and adjacent segment disease showed statistically significant improvement in all of these clinical outcome scores, although the mean changes in the Short Form-12 Mental Component Summary, Oswestry Disability Index, and Visual Analog Scale (back pain) were lower. The overall radiological fusion rate was 94.4%. Superior radiological outcomes (fusion .90%) were observed in patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and failed posterior fusion, whereas in adjacent segment disease, it was 80%.

CONCLUSION: ALIF is an effective treatment for degenerative disk disease (with and without radiculopathy) and spondylolisthesis. Although results were promising for scoliosis, failed posterior fusion, and adjacent segment disease, further studies are necessary to establish the effectiveness of ALIF in these conditions.

05/01/201504/01/2015

Long-term outcome and prognostic factors after C2 ganglion decompression in 68 consecutive patients with intractable occipital neuralgia

Acta Neurochir (2015) 157:85–92

Occipital neuralgia is a rare cause of severe headache characterized by paroxysmal shooting or stabbing pain in the distribution of the greater occipital or lesser occipital nerve. In cases of intractable occipital neuralgia, a definite cause has not been uncovered, so various types of treatment have been applied. The aim of this study is to evaluate the prognostic factors, safety, and long-term clinical efficacy of second cervical (C2) ganglion decompression for intractable occipital neuralgia.

Methods Retrospective analysis was performed in 68 patients with medically refractory occipital neuralgia who underwent C2 ganglion decompression. Factors based on patients’ demography, pre- and postoperative headache severity/characteristics, medication use, and postoperative complications were investigated. Therapeutic success was defined as pain relief by at least 50 % without ongoing medication.

Results The visual analog scale (VAS) score was significantly reduced between the preoperative and most recent follow-up period. One year later, excellent or good results were achieved in 57 patients (83.9 %), but poor in 11 patients (16.1 %). The long-term outcome after 5 years was only slightly less than the 1-year outcome; 47 of the 68 patients (69.1 %) obtained therapeutic success. Longer duration of headache (over 13 years; p=0.029) and presence of retro-orbital/frontal radiation (p=0.040) were significantly associated with poor prognosis.

Conclusions In the current study, C2 ganglion decompression provided durable, adequate pain relief with minimal complications in patients suffering from intractable occipital neuralgia. Due to the minimally invasive and nondestructive nature of this surgical procedure, C2 ganglion decompression is recommended as an initial surgical treatment option for intractable occipital neuralgia before attempting occipital nerve stimulation. However, further study is required to manage the pain recurrence associated with longstanding nerve injury.

02/01/201501/01/2015

Effect of Vascular Anatomy on the Formation of Basilar Tip Aneurysms

Neurosurgery 76:62–66, 2015

The pathogenesis of intracranial aneurysms is multifactorial and includes genetic, environmental, and anatomic influences. Hemodynamic stress plays a particular role in the formation of intracranial aneurysms, which is conditioned by the geometry and morphology of the vessel trees.

OBJECTIVE: To identify image-based morphological parameters that correlated with the formation of basilar artery tip aneurysms (BTAs) in a location-specific manner.

METHODS: Morphological parameters obtained from computed tomographic angiographies of 33 patients with BTAs and 33 patients with aneurysms at other locations were evaluated with Slicer, an open-source image analysis software, to generate 3-dimensional models of the aneurysms and surrounding vascular architecture. We examined the diameters and vessel-to-vessel angles of the main vessels at the basilar bifurcation in patients with and without BTAs. To control for genetic and other risk factors, only patients with at least 1 aneurysm were included. Univariate and multivariate analyses were performed to determine statistical significance.

RESULTS: Sixty-six patients (33 with BTAs, 33 with other aneurysms) who were evaluated from 2008 to 2013 were analyzed. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (odds ratio, 1.04; P = 1.42 · 1023) and a smaller basilar artery diameter (odds ratio, 0.23; P = .02) were most strongly associated with BTA formation after adjustment for other morphological and clinical variables.

CONCLUSION: Larger posterior cerebral artery angles and smaller basilar artery diameters are associated with the formation of basilar tip aneurysms. These parameters are easily measurable by the clinician and will aid in screening strategies in high-risk patients.

31/12/201430/12/2014

Instrumentation of the Posterior Thoracolumbar Spine: From Wires to Pedicle Screws

Operative Neurosurgery 10:497–505, 2014

Over the past 120 years, spinal stabilization has advanced immensely. An updated review highlighting these advancements has not been performed in the past 20 years.

The objective of this report is to provide a historical assessment of the decades outlining various key innovators, their techniques, and instrumentation.

It is important to provide new generations of surgeons and students with historical evidence of the value of developing new techniques and instrumentation to improve patient care and outcomes.

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