Month: December 2010

Posted on

Shunting for the Treatment of Arachnoid Cysts in Children

Neurosurgery 67:1632–1636, 2010 DOI: 10.1227/NEU.0b013e3181f94476

The optimal treatment of symptomatic arachnoid cysts remains controversial.

OBJECTIVE: We present a single-institution experience on surgical treatment of arachnoid cysts.

METHODS: Between January 1983 and January 2008, 92 patients with symptomatic arachnoid cysts underwent surgery at our institute. All patients were evaluated with CT and/or MRI and were operated upon and had regular follow-up examinations.

RESULTS: There were 60 males and 32 females. The mean age was 3.6 years (range, 2 days to 14 years). Forty-eight cysts (52%) were within the sylvian fissure, 16 (17%) were in the cerebral convexity, 15 (16%) were infratentorial, 10 (11%) were in the interhemispheric fissure, and 3 (4%) were parasellar. Cystoperitoneal shunt was placed in 67 (73%) patients; ventricular drainage alone was performed in 14 (15%) patients; and combined drainage of the ventricular system and cyst, using a 3-way connector, was performed in 8 (9%) patients. Craniotomy and fenestration of the cyst was performed in 2 (2%) patients, whereas total excision of the cyst was performed in 1 patient. Shunt revision for various reasons was performed in 34 patients (39%), whereas 13 (14%) patients required more than one revision. Complete alleviation of symptoms was achieved in all patients after treatment, regardless of cyst reduction. After a mean follow-up of 8.5 years no further enlargement of the arachnoid cysts was noted.

CONCLUSION: Shunt placement is a safe and effective surgical treatment of symptomatic arachnoid cysts in children. Cyst reduction is greater in children younger than 2 years of age.

Posted on

Dynamic stabilization adjacent to single-level fusion: Part II. No clinical benefit for asymptomatic, initially degenerated adjacent segments after 6 years follow-up

Eur Spine J (2010) 19:2181–2189 DOI 10.1007/s00586-010-1517-4

Progression of degeneration is often described in patients with initially degenerated segment adjacent to fusion (iASD) at the time of surgery. The aim of the present study was to compare dynamic fixation of a clinically asymptomatic iASD, with circumferential lumbar fusion alone.

60 patients with symptomatic degeneration of L5/S1 or L4/L5 (Modic C 2) and asymptomatic iASD (Modic = 1, confirmed by discography) were divided into two groups. 30 patients were treated with circumferential single-level fusion (SLF). In dynamic fixation transition (DFT) patients, additional posterior dynamic fixation of iASD was performed. Preoperatively, at 12 months, and at a mean follow-up of 76.4 (60–91) months, radiological (MRI, X-ray) and clinical (ODI, VAS, satisfaction) evaluations assessed fusion, progression of adjacent segment degeneration (PASD), radiologically adverse events, functional outcome, and pain.

At final follow-up, two nonfusions were observed in both groups. 6 SLF patients and 1 DFT patient presented a PASD. In two DFT patients, a PASD occurred in the segment superior to the dynamic fixation, and in one DFT patient, a fusion of the dynamically fixated segment was observed. 4 DFT patients presented radiological implant failure. While no differences in clinical scores were observed between groups, improvement from pre-operative conditions was significant (all p<0.001). Clinical scores were equal in patients with PASD and/or radiologically adverse events. We do not recommend dynamically fixating the adjacent segment in patients with clinically asymptomatic iASD. The lower number of PASD with dynamic fixation was accompanied by a high number of implant failures and a shift of PASD to the superior segment.

Posted on

Posterior fossa ependymomas: new radiological classification with surgical correlation

Childs Nerv Syst (2010) 26:1765–1772. DOI 10.1007/s00381-010-1251-6

The key determinant of long-term outcome in infratentorial ependymomas remains the extent of surgical resection. We describe a new radiological classification system which is validated against surgical findings and correlated with risk of post-operative residual tumour.

Methods Twenty-five consecutive patients (12 females, mean age 4.9 years, range 0.5–17 years) with infratentorial ependymomas were studied. Lesions were classified on preoperative MRI according to the pattern of extension, brainstem displacement and involvement of the obex, as lateral-type or midfloor-type tumours. Twenty-one operative records were reviewed with respect to the microanatomical tumour origin by a paediatric neurosurgeon, blinded to MRI findings. Follow-up imaging studies were evaluated for residual tumour.

Results There were 15 cases of midfloor-type tumour (anterior displacement of brainstem, infiltration of obex) and 10 cases of lateral-type tumour (lateral displacement of brainstem, obex free of tumour). Extension into prepontine or cerebellopontine cisterns was more common in lateraltype tumours. Agreement between the radiological classification and tumour origin, as defined by operative records, was seen in 18 out of 20 cases. Risk of residual tumour in lateral-type tumours was more than twice that of midfloortype tumours (80% vs. 33%, p=0.04). Risk of tumour residual was also significantly higher when vessel encasement or prepontine extension was observed.

Conclusions Infratentorial ependymomas can be preoperatively classified as lateral-type or midfloor-type tumours. This correlates well with operative findings. Lateral-type tumours have significantly increased risk of residual tumour compared to midfloor- type tumours and this may influence intensity of imaging surveillance.

Posted on

Less Invasive Surgical Correction of Adult Degenerative Scoliosis. Part II: Complications and Clinical Outcome

Neurosurgery 67:1609–1621, 2010 DOI: 10.1227/NEU.0b013e3181f918cf

Surgical correction of adult degenerative scoliosis is a technically demanding procedure with a considerable complication rate. Extensive blood loss has been identified as a significant factor linked to unfavorable outcome.

OBJECTIVE: To report on the complication profile and clinical outcomes obtained with less invasive image-guided surgical correction of degenerative (de novo) scoliosis in a high-risk population.

METHODS: Thirty patients (age, 64-88 years) with progressive postural impairment, back pain, radiculopathy, and neurogenic claudication caused by degenerative scoliosis were treated by less invasive image-guided correction (3-8 segments) by multisegmental transforaminal lumbar interbody fusion and facet fusions. With a mean follow-up of 19.6 months, intraoperative blood loss, curve correction, fusion and complication rates, duration of hospitalization, incidence of hardware-related problems, and clinical outcome parameters were assessed using multivariate analysis.

RESULTS: Satisfactory multiplanar correction was obtained in all patients. Mean intraoperative blood loss was 771.7±231.9 mL, time to full ambulation was 0.8 ± 0.6 days, and length of stay was 8.2 ± 2.9 days. After 12 months, preoperative SF12v2 physical component summary scores (20.2 ± 2.6), visual analog scale scores (7.5 ± 0.8), and Oswestry disability index (57.2 ± 6.9) improved to 34.6 ± 3.9, 2.63 ± 0.6, and 24.8 ± 7.1, respectively. The rate of major and minor complications was 23.4% and 59.9%, respectively. Ninety percent of patients rated treatment success as excellent, good, or fair.

CONCLUSION: Less invasive image-guided correction of degenerative scoliosis in elderly patients with significant comorbidity yields a favorable complication profile. Significant improvements in spinal balance, pain, and functional scores mirrored expedited ambulation and early resumption of daily activities. Less invasive techniques appear suitable to reduce periprocedural morbidity, especially in elderly patients and individuals with significant medical risk factors.

Posted on

A Novel Aneurysm Clip Design for Atheromatous, Thrombotic, or Previously Coiled Lesions

Neurosurgery 67[ONS Suppl 2]:ons333–ons341, 2010 DOI: 10.1227/NEU.0b013e3181f7451b

Large and giant lesions often have thicker, atheromatous walls as well as intra-aneurysmal thrombus that combine to prevent traditional clips from closing properly in some cases.

OBJECTIVE: To report the development and use of a novel clip design specifically tailored to treat atheromatous, thrombotic, or previously coiled aneurysms.

METHODS: We retrospectively reviewed the records of 6 patients with complex aneurysms not amenable to simple neck clipping and not considered appropriate for endovascular therapy who were treated using a novel ‘‘compression’’ clip design. We describe the development and use of a novel aneurysm clip design with blades that are not opposed at rest to allow direct clipping of atheromatous, thrombotic, and previously coiled aneurysms.

RESULTS: Four patients had recurrent, previously coiled aneurysms; one of these also had a large thrombotic component. Two patients had complex lesions with heavy atheroma involving a portion of their aneurysms. There were no complications related to the use of the clip, and all patients did well without neurological complications. In every case, the clip allowed straightforward obliteration of the aneurysm without the need for temporary vascular occlusion, aneurysmorrhaphy, or removal of an intra-aneurysmal coil mass. All patients underwent intraoperative angiography to confirm obliteration of the aneurysm with preservation of the normal vasculature.

CONCLUSION: Atheromatous, thrombotic, and previously coiled aneurysms may not be treatable with simple neck clipping and may not be curable with endovascular therapy. For such cases, we designed a novel ‘‘compression’’ clip that has been used safely and successfully in our experience with good short-term follow-up.

Posted on

Re-operation for persistent hemifacial spasm after microvascular decompression with the aid of intraoperative monitoring of abnormal muscle response

Acta Neurochir (2010) 152:2113–2118. DOI 10.1007/s00701-010-0837-9

Microvascular decompression (MVD) is the only solution that can effectively control hemifacial spasm (HFS). Regarding treatment of the patients who failed the first operation, it is still controversial. We tried to evaluate the safety and efficiency of the early re-exploration for such kinds of patients.

Methods Thirteen patients failed the first MVD and received a second MVD procedure. The spasm was not resolved at all or became even more severe after the first MVD. Abnormal muscle response (AMR) persisted during the first MVD operation or disappeared once but emerged again. The patient had a strong will to do the re-operation and was aware of the high risks of operative complications.

Results All the 13 patients got good or excellent spasm resolution immediately after the re-operation, which involved whole-range exploration and intraoperative AMR monitoring; however, there were two cases (15.4%) of permanent facial weakness and three cases (23.0%) of transient facial weakness.

Conclusions Our experience on early repeat MVD is whole-range exploration and intraoperative AMR monitoring; in other words, re-operation cannot rely too much on experience

Posted on

The influence of approach side on facet preservation in microscopic bilateral decompression via a unilateral approach for degenerative lumbar scoliosis

J Neurosurg Spine 13:000–000, 2010. (DOI: 10.3171/2010.5.SPINE091001)

The authors compared the clinical outcomes of microscopic bilateral decompression via a unilateral approach (MBDU) for the treatment of degenerative lumbar scoliosis (DLS) and for lumbar canal stenosis (LCS) without instability. The authors also compared postoperative spinal instability in terms of different approach sides (concave or convex) following the procedure.

Methods. The authors retrospectively reviewed data obtained in 50 consecutive patients (25 in the DLS group and 25 in the LCS group) who underwent MBDU; the minimum follow-up period was 2 years. Patients with DLS were divided into 2 subgroups according to the surgical approach side: a concave group (23 segment) and a convex group (17 segments). The Japanese Orthopaedic Association Scale scores for the assessment of low-back pain were evaluated before surgery and at final follow-up. The Japanese Orthopaedic Association Scale scores and recovery rates were compared between the DLS and LCS groups, and between the convex and concave groups. Cobb angle and scoliotic wedging angle (SWA) were evaluated on standing radiographs before surgery and at final follow-up. Facet joint preservation (the percentage of preservation) was assessed on pre- and postoperative CT scans, compared between the LCS and DLS groups, and compared between the concave and convex groups. The influence of approach side on postoperative progression of segmental instability was also examined in the DLS group.

Results. The mean recovery rate was 58.7% in the DLS and 62.0% in the LCS group. The mean recovery rate was 58.6% in the convex group and 60.6% in the concave group. There were no significant differences in recovery rates between the LCS and DLS groups, or between the DLS subgroups. The mean Cobb angles in the DLS group were significantly increased from 12.7° preoperatively to 14.1° postoperatively (p < 0.05), and mean preoperative SWAs increased significantly from 6.2° at L3–4 and 4.1° at L4–5 preoperatively to 7.4° and 4.9°, respectively, at final follow-up (p < 0.05). There was no significant difference in percentage of preservation between the DLS and LCS groups. The mean percentages of preservation on the approach side in the DLS group at L3–4 and L4–5 were 89.0% and 83.1% in the convex group, and those in the concave group were 67.3% and 77.6%, respectively. The percentage of preservation at L3–4 was significantly higher in the convex than the concave group. The mean SWA had increased in the concave group (p = 0.01) but not the convex group (p = 0.15) at final follow-up.

Conclusions. The MBDU can reduce postoperative segmental spinal instability and achieve good postoperative clinical outcomes in patients with DLS. The convex approach provides surgeons with good visibility and improves preservation of facet joints.

Posted on

Cavernous Malformations of the Brainstem Presenting in Childhood: Surgical Experience in 40 Patients

Neurosurgery 67:1589–1599, 2010 DOI: 10.1227/NEU.0b013e3181f8d1b2

Brainstem cavernous malformations (BSCMs) are believed to compose 9% to 35% of all cerebral cavernous malformations, but these lesions have been reported in children in very limited numbers.

OBJECTIVE: To review surgical outcomes of pediatric patients with BSCMs treated at 1 institution.

METHODS: We retrospectively analyzed the course of 40 pediatric patients (19 males, 21 females; age range, 10 months to 18.9 years; mean, 12.3 years) who underwent surgery between 1984 and 2009. Age, sex, presenting symptoms, location of lesion, surgical approach, new postoperative deficits, Glasgow Outcome Scale score, recurrences, and resolution of baseline symptoms were recorded.

RESULTS: Thirty-nine patients experienced hemorrhage before surgery. Lesion locations included the pons (n = 22), midbrain (n = 4), midbrain and thalamus (n = 4), pontomesencephalic junction (n = 3), medulla (n = 3), pontomedullary junction (n = 3), and cervicomedullary junction (n = 1). Mean lesion size was 2.3 cm. Mean length of hospital stay was 10.7 days. The average clinical follow-up was 31.9 months in 36 patients with follow-up after discharge. At last follow-up, 5 patients had experienced symptoms and/ or imaging consistent with rehemorrhage, either from a residual that enlarged or true recurrence (5.25% annual rebleed risk per patient after surgery); 2 required reoperation for further resection of cavernoma. Mean Glasgow Outcome Scale score was 4.2 on admission, 4.05 at discharge, and 4.5 at latest follow-up. Preoperative symptoms and deficits improved in 16 patients (40%). New neurological deficits developed in 19 patients (48%) and resolved in 9, leaving 10 patients (25%) with new permanent deficit.

CONCLUSION: Compared with adults, pediatric patients with BCSMs tend to have larger lesions and higher rates of recurrence (regrowth of residual lesion). Given the greater life expectancy of children, surgical treatment seems warranted in those with surgically accessible lesions that have bled. Outcomes were similar to those in our adult series of patients with BSCMs.

Posted on

Long-term Outcome After Resection of Intraspinal Ependymomas: Report of 86 Consecutive Cases

Neurosurgery 67:1622–1631, 2010 DOI: 10.1227/NEU.0b013e3181f96d41

Objective: To evaluate progression-free survival, overall survival (OS) and long-term clinical outcome in a consecutive series of 86 patients with intraspinal ependymomas.

METHODS: Medical charts were retrospectively reviewed. Surviving patients voluntarily participated in a clinical history and physical examination that focused on neurological function and current tumor status.

RESULTS: Follow-up data are nearly 100% complete; mean follow-up time was 82 months. Eighty-five patients (99%) had surgery as a first-line treatment; 14 (17%) of these patients received adjuvant radiotherapy. Of the 85 patients who underwent primary surgery, gross total resection was performed in 60 patients (71%) and subtotal resection in 25 patients (29%). Ten-year progression-free survival rate was 75%; 5-year OS, 97%; and 10-year OS, 91%. Reduced preoperative neurological function and older age at diagnosis were significantly associated with increased risk of death. At follow-up, spontaneous regression of residual tumor after primary surgery may have occurred in 7 of 19 patients (37%). More than 75% of patients had neurological function compatible with an independent life at follow-up. Good preoperative neurological function was significantly associated with favorable outcome. It was not possible to evaluate the effect of radiotherapy on progression-free survival and OS.

CONCLUSION: Gross total resection remains the optimal treatment for patients with spinal ependymoma. Patients should be monitored with a clinical examination and magnetic resonance imaging at regular intervals up to 10 years after surgery.

Posted on

Intraventricular migration of the bone dust. Is a second operation for removal necessary?

Childs Nerv Syst. DOI 10.1007/s00381-010-1339-z

As the number of endoscopic third ventriculostomy (E3V) operations increase, new rare complications are encountered. In this article, a complication caused by bone particles that migrated into the third ventricle will be described. Additionally, the methods of avoidance as well as the necessity of a new approach will be discussed.

Methods After the video images of the first and second operations of a patient who was subjected to E3V twice were compared, it was discovered that one of the bone particles within the ventricle had occluded the ostium after the second operation. Most of the bones were removed and their pathological investigations were performed.

Results Video images of the patient, surgical observations of the second operation, emergence of the time of dysfunction, and other similar cases in the literature were assessed, and it was concluded that the bones that localized intraventricularly were living tissues.

Discussion Abandoning usage of bone dust for sealing burr holes is a solution to avoid this complication. In addition, it should be kept in mind that intraventricular bone particles might grow and lead to obstructions. If such particles are detected, removal of the bones in certain locations before formation of neovascularization can be an option.

Posted on

An Assessment of Current Brain Targets for Deep Brain Stimulation Surgery With Susceptibility- Weighted Imaging at 7 Tesla

Neurosurgery 67:1745–1756, 2010 DOI: 10.1227/NEU.0b013e3181f74105

Deep brain stimulation (DBS) surgery is used for treating movement disorders, including Parkinson disease, essential tremor, and dystonia. Successful DBS surgery is critically dependent on precise placement of DBS electrodes into target structures. Frequently, DBS surgery relies on normalized atlas-derived diagrams that are superimposed on patient brain magnetic resonance imaging (MRI) scans, followed by microelectrode recording and macrostimulation to refine the ultimate electrode position. Microelectrode recording carries a risk of hemorrhage and requires active patient participation during surgery.

OBJECTIVE: To enhance anatomic imaging for DBS surgery using high-field MRI with the ultimate goal of improving the accuracy of anatomic target selection.

METHODS: Using a 7-T MRI scanner combined with an array of acquisition schemes using multiple image contrasts, we obtained high-resolution images of human deep nuclei in healthy subjects.

RESULTS: Superior image resolution and contrast obtained at 7 T in vivo using susceptibility-weighted imaging dramatically improved anatomic delineation of DBS targets and allowed the identification of internal architecture within these targets. A patient-specific, 3-dimensional model of each target area was generated on the basis of the acquired images.

CONCLUSION: Technical developments in MRI at 7 T have yielded improved anatomic resolution of deep brain structures, thereby holding the promise of improving anatomicbased targeting for DBS surgery. Future study is needed to validate this technique in improving the accuracy of targeting in DBS surgery.

Posted on

Partially thrombosed intracranial aneurysms: symptoms, evolution, and therapeutic management

Acta Neurochir (2010) 152:2133–2142. DOI 10.1007/s00701-010-0772-9

Partially thrombosed intracranial aneurysms (PTIAs) are different from saccular or nonthrombosed giant or large aneurysms, as they are characterized by multiple intramural thrombotic phenomena related to recurrent vessel wall dissections.

Methods We retrospectively reviewed clinical and radiological files of 23 consecutive patients with PTIAs (mean age 49.3 years). Twenty-two lesions were studied by magnetic resonance imaging (MRI). Patients were managed by endovascular treatments, medically with steroids, or conservatively.

Results Thirteen patients presented with progressive neurological symptoms. Subarachnoid hemorrhage was suspected but not proven in three. At MRI, 90.9% of PTIAs caused mass effect; perilesional T2 hypersignal compatible with edema was evident in 13.6%. Aneurysmal wall enhancement was detectable in 63.2% of the PTIAs and considered a marker of inflammatory processes. Parent artery occlusion was performed in seven patients with clinical improvement in six. Selective coiling was proposed in three patients (one improved, one remained stable, and one experienced symptoms progression). Three patients were treated with steroids and improved. Ten patients were managed conservatively: eight because spontaneous thrombosis of the lesion had been diagnosed and two because of clinical and radiological stability.

Conclusions The natural history of PTIAs is different from other aneurysms. They most commonly present with progressive neurological symptoms due to mass effect. MRI properly diagnoses PTIAs and allows precise followup, more accurately than angiography because it detects prominent “abluminal” features indicating inflammation and neovascularization. Spontaneous thrombosis is part of the natural history of PTIAs and it should be taken in consideration when discussing the therapeutic management.

Posted on

Vascular Endothelial Growth Factor: The Major Factor for Tumor Neovascularization and Edema Formation in Meningioma Patients

Neurosurgery 67:1703–1708, 2010 DOI: 10.1227/NEU.0b013e3181fb801b

Peritumoral brain edema (PTBE) may be crucial in the clinical outcome of meningioma patients. The underlying pathogenetic key mechanism has so far not been determined. Sex, age, tumor size, location, involvement of other structures, or the histological appearance was not found to sufficiently explain PTBE formation in meningiomas.

OBJECTIVE: As PTBE formation is widely accepted to be vasogenic, we investigated the role of vascular endothelial growth factor (VEGF) and pial supplying vessels in a series of World Health Organization (WHO) grade I meningiomas.

METHODS: A total of 79 patients with WHO grade I meningiomas were immunohistochemically studied for VEGF and MIB-1. Pre- and postoperative magnetic resonance imaging including 3-dimensional reconstruction of 1.3-mm thick layers, with calculation of tumor and edema volume, was performed. Intraoperatively, the vascular supply and arachnoidal state were noted by the neurosurgeon.

RESULTS: VEGF was found to be exclusively confined to meningioma tumor cells. We identified 4 different patterns. VEGF and supplying pial vessels were found in 14 meningioma patients, pial vascular supply only in 3, VEGF expression only in 46, and neither VEGF expression nor supplying pial vessels in 16. Only the occurrence of both pial vascular supply and tumor VEGF expression was found to be correlated with PTBE formation (P , .002).

CONCLUSION: Our data suggest that VEGF may be crucial in angiogenesis and therefore indirectly in PTBE formation in World Health Organization grade I meningiomas

Posted on

Investigating shunt function using continuous intracranial pressure monitoring in adults: single center experience

J Neurosurg 113:1326–1330, 2010. (DOI: 10.3171/2010.8.JNS1067)

Managing symptomatic ventriculoperitoneal shunts with no clear evidence of shunt malfunction either clinically or radiologically can be a difficult task. The aim of this study was to assess intracranial pressure (ICP) monitoring as a method of investigating shunt function.

Methods. The authors performed a retrospective analysis of 38 continuous ICP monitoring procedures done in patients with ventriculoperitoneal shunts and suspected shunt malfunction.

Results. Thirty-eight procedures were performed in 31 patients between January 2005 and October 2008. Sixteen recordings were normal, 6 revealed overdrainage or low pressure, 11 indicated underdrainage or high pressure, and 5 showed variable shunt function. Based on the findings after 20 procedures (53%), patients were treated conservatively: 4 by readjusting the valve setting and 16 by referral to the headache neurologist for medical treatment. Forty-five percent of the conservatively treated patients improved. Surgical exploration was undertaken following 18 procedures (47%); 72% of the surgically treated patients improved.

Conclusions. Continuous ICP monitoring using an intraparenchymal probe is a safe and effective method of investigating adult hydrocephalus.

Posted on

Surgical treatment of trigeminal neuralgia. Results from the use of glycerol injection, microvascular decompression, and rhizotomia

Acta Neurochir (2010) 152:2125–2132. DOI 10.1007/s00701-010-0840-1

The study aims to assess the efficacy and safety of surgical treatment of trigeminal neuralgia (TN) in our department and to identify prognostic factors.

Methods Seventy patients receiving surgical treatment for TN during the period 2003–2004 were included in this retrospective study. The surgical procedures used were glycerol injection (GI), microvascular decompression (MVD), or rhizotomia (RIZ). All patients were divided into spontaneous onset TN type1 (brief lancinating pain) or TN type 2 (continuous pain component). Two patients had bilateral TN; each side was regarded as a separate case. These 70 patients had a total of 160 interventions (110 GI, 40 MVD, and ten RIZ) performed in the period 1998–2007. Data were obtained by chart review and telephone interview. Patients provided information about pre- and postoperative pain characteristics including subtype, duration, intensity, and the use of antiepileptic drugs. Outcome was evaluated using a pain vector diagram.

Results To quantify self-reported pain, we developed a new vector-based pain diagram. The subtype of TN was shown to be a very important prognostic factor. One year after MVD, 90% of patients with type 1 TN still had positive effect, whereas this was only true in 73% of patients with type 2 TN. After RIZ, the results were 71% and 33% for types 1 and 2, respectively. For comparison, GI had a significant lower effect but if the treatment led to hypoesthesia, 41% continued to have a positive effect 1 year after surgery, compared to only 24% if postoperative sensation was normal. Type 2 TN was found to be dominated by women with left-sided TN outside the V2 dermatome and with a lower probability of a neurovascular conflict. As expected, 1/5 of the cases developed postoperative hypoesthesia in the face following a nerve destructive procedure (RIZ and GI). Using MVD, the risk of serious side effects was about 4%. Complementary and alternative treatment had no general or permanent effect in the investigated population—quite the contrary.

Conclusions Regarding prognosis and outcome, we find that it is very important to classify TN in subgroups (types 1 and 2). Dealing with medically treatment-resistant type 1 TN, MVD and RIZ are reasonably safe and effective interventions. The surgical results dealing with type 2 TN are still very poor. All patients with medically treatmentresistant TN should be offered referral to a neurosurgical unit with experience in treating this painful disease. We recommend using a vector-based pain diagram when evaluating the outcome of multiple interventions.

Posted on

Minimally invasive endoscopic transventricular hemispherotomy for medically intractable epilepsy: a new approach and cadaveric demonstration

J Neurosurg Pediatrics 6:000–000, 2010. (DOI: 10.3171/2010.9.PEDS10267)

Surgery for medically intractable epilepsy secondary to unihemispheric pathology has evolved from more aggressive hemispherectomy to less aggressive variations of hemispherotomy. The authors propose a novel minimally invasive endoscopic hemispherotomy that should give results comparable to conventional open craniotomy and microsurgery.

Methods. Endoscopic transventricular hemispherotomy was performed in 5 silicon-injected cadaveric heads in the authors’ minimally invasive neurosurgery laboratory. The lateral ventricle was accessed endoscopically through a frontal and occipital bur hole. White matter disconnections were performed to unroof the temporal horn and to disconnect the frontobasal region, corpus callosum, and fornix.

Results. Using an endoscopic transventricular approach, all white matter disconnections were successfully performed in all 5 cadavers.

Conclusions. The authors have demonstrated the feasibility of endoscopic transventricular hemispherotomy in a cadaveric model. The technique is simple and could be useful in a subgroup of patients with parenchymal volume loss and ventriculomegaly.

Posted on

Is MRI a reliable tool to locate the electrode after deep brain stimulation surgery? Comparison study of CT and MRI for the localization of electrodes after DBS

Acta Neurochir (2010) 152:2029–2036. DOI 10.1007/s00701-010-0779-2

MRI has been utilized to localize the electrode after deep brain stimulation, but its accuracy has been questioned due to image distortion. Under the hypothesis that MRI is not adequate for evaluation of electrode position after deep brain stimulation, this study is aimed at validating the accuracy of MRI in electrode localization in comparison with CT scan. Methods Sixty one patients who had undergone STN DBS were enrolled for the analysis. Using mutual information technique, CT and MRI taken at 6 months after the operation were fused. The x and y coordinates of the centers of electrodes shown of CT and MRI were compared in the fused images to calculate average difference at five different levels. The difference of the tips of the electrodes, designated as the z coordinate, was also calculated. Results The average of the distance between the centers of the electrodes in the five levels estimated in the fused image of brain CT and MRI taken at least 6 months after STN DBS was 1.33 mm (0.1–5.8 mm). The average discrepancy of x coordinates for all five levels between MRI and CT was 0.56±0.54 mm (0–5.7 mm), the discrepancy of y coordinates was 1.06±0.59 mm (0–3.5 mm), and for the z coordinate, it was 0.98±0.52 mm (0–3.1 mm) (all p values <0.001). Notably, the average discrepancy of x coordinates at 3.5 mm below AC–PC level, i.e., at the STN level between MRI and CT, was 0.59±0.42 mm (0–2.4 mm); the discrepancy of y coordinates was 0.81±0.47 mm (0–2.9 mm) (p values<0.001). Conclusions The results suggest that there was significant discrepancy between the centers of electrodes estimated by CT and MRI after STN DBS surgery.

Posted on

A Critical Evaluation of Vestibular Schwannoma Surgery for Patients Younger Than 40 Years of Age

Neurosurgery 67:1646–1654, 2010 DOI: 10.1227/NEU.0b013e3181f8d3d3

There are few published prospective data sets specifically focusing on patients younger than 40 years old undergoing microsurgery for vestibular schwannoma.

OBJECTIVE: We describe functional outcomes and long-term tumor control after surgery in patients younger than 40 years old enrolled in a prospectively collected database over a 25-year period.

METHODS: We selected all vestibular schwannoma patients from a prospectively collected database who were younger than 40 years old at the time of surgical resection for a vestibular schwannoma. Rates of tumor control and hearing preservation were analyzed using Kaplan-Meier analysis, and risk factors for facial nerve palsy, hearing loss, and trigeminal neuropathy were analyzed using multivariate logistic regression.

RESULTS: A total of 204 patients younger than 40 years of age met our inclusion criteria and were included in the analysis. Our data indicate that surgical resection leads to durable long-term freedom from tumor recurrence or progression in 89% of young patients at 15 years of follow-up. Consistent with other published series, hearing was preserved in 68% of patients with smaller tumors (,3 cm). Facial nerve function was preserved in 76% of patients with smaller tumors and 52% of patients with larger tumors (P , .001). On multivariate logistic regression, tumor size was a significant predictor of hearing loss, whereas gross total resection was nearly a significant predictor of hearing loss controlling for other variables (P = .06).

CONCLUSION: We present the largest prospectively studied cohort of young patients undergoing microsurgical resection of vestibular schwannoma. These data suggest that surgical resection provides excellent long-term tumor control in these patients

Posted on

Prediction of neurological deficits and recovery after surgery in the supplementary motor area: a prospective study in 26 patients

J Neurosurg 113:1152–1163, 2010.(DOI: 10.3171/2010.6.JNS1090)

Resection of lesions involving the supplementary motor area (SMA) may result in immediate postoperative motor and speech deficits that are reversible in most cases. In the present study the authors aimed to determine the critical involvement of SMA in the lesioned and healthy hemispheres in this functional recovery. They hypothesized that compensatory mechanisms take place following surgery in the SMA, and that these mechanisms can involve either the lesioned or the non-lesioned hemisphere. In addition, they hypothesized that a correlation will be present between the functional MR imaging (fMR) imaging–related activation in the SMA and the occurrence of a functional deficit during intraoperative cortical stimulation.

Methods. Twenty-six patients scheduled for resection of space-occupying lesions involving, or in the vicinity of, the SMA were recruited. Patients underwent an fMR imaging examination that included finger-tapping and verbgeneration tests to assess for motor and language functions. Intraoperatively direct cortical stimulation (DCS) of the SMA region was performed while patients were monitored for language and motor functions using tests similar to those used for the fMR imaging. Task dysfunction during DCS assessed the critical involvement of the SMA in the tested functions. Neurological evaluations were performed prior to surgery and at 3 time points within a month following surgery. A region of interest–based approach was used to evaluate fMR imaging blood oxygen level–dependent activation level and asymmetry in the SMA. These measurements were later compared with the intraoperative DCS and neurological findings.

Results. Functional MR imaging showed greater activation and dominance of the SMA in the lesioned hemisphere in patients who exhibited no motor or language dysfunction during DCS. In addition, patients with the highest activation of the SMA in the lesioned hemisphere for language and motor tests showed stronger coupling of this region with ipsilateral motor and language networks. In contrast, activation in the nonlesioned hemisphere did not correspond with DCS results.

Conclusions. The authors’ findings demonstrate the necessity of activation in the vicinity of the lesioned SMA for functional compensation in motor and language tasks. It is possible that more effective functional coupling of the SMA with motor and language areas in the same hemisphere prevents dysfunctions following surgical intervention. Importantly, fMR imaging activation in the unaffected SMA was not sufficient for development of functional compensation and, if anything, indicated decompensation.

Posted on

Visualization of the Anterior Cerebral Artery Complex With a Continuously Variable-View Rigid Endoscope: New Options in Aneurysm Surgery

Neurosurgery 67[ONS Suppl 2]:ons321–ons324, 2010 DOI: 10.1227/NEU.0b013e3181f74548.

Neuroendoscopy is increasingly used as an adjunctive tool in intracranial aneurysm surgery.

OBJECTIVE: To assess the versatility of a prototype continuously variable-view rigid endoscope in visualizing the anterior cerebral artery complex.

METHODS: In 5 formaldehyde-fixed, arterially injected specimens, a standard frontolateral approach was used on both sides. After meticulous microsurgical dissection using this approach, the prototype of a multivariable rigid endoscope (EndoCAMeleon; Karl Storz GmbH & Co, Tuttlingen, Germany) was inserted. It is a rigid endoscope that is capable of changing its angle of view while remaining stationary and shape invariant. We inspected the anterior cerebral artery complex, using and testing the capabilities of the device.

RESULTS: The continuously variable viewing mechanism enables the surgeon to adjust the field of view continuously and to optimize the visualization of the neurovascular structures. Because of the rigid tip combined with the continuously variable viewing mechanism, the need to move the endoscope within the surgical field was minimal. The field of view changes, but the tip itself hardly moves. The EndoCAMeleon was able to enhance both the visibility of the anterior cerebral artery complex and the accessibility of the A1 and A2 arterial walls to a range of approximately 270 degrees.

CONCLUSION: The EndoCAMeleon enhances the visibility of the anterior cerebral artery complex and facilitates endoscope-assisted inspection, planning of clip application, and clip control.

Proudly powered by WordPress