Posts

Posted on

Endoscopic Treatment of Isolated Fourth Ventricle: Clinical and Radiological Outcome

Neurosurgery 70:847–859, 2012 DOI: 10.1227/NEU.0b013e318236717f

Treatment of an isolated fourth ventricle should be considered when clinical symptoms or a significant mass effect occur.

OBJECTIVE: To report clinical and radiographic outcomes after endoscopic transaqueductal or transcisternal stent placement into the fourth ventricle. METHODS: In 19 patients (age, 34th week of gestation-20 years; median age, 17.5 months), 22 endoscopic procedures were performed. Either an aqueductoplasty or, in cases with a supratentorially extended fourth ventricular component, an interventricular fenestration was performed. In all patients, a stent connected to the cerebrospinal fluid–diverting shunt was placed through the fenestration. Surgical complications and radiological and clinical outcomes are reported.

RESULTS: All 19 patients had a mean follow-up of 26.9 ± 18.2 months. No persisting neurological complications were observed; 27.3% of patients experienced complete resolution of presenting symptoms, whereas 68.3% demonstrated partial resolution. Symptoms with short duration (< 4 weeks) resolved completely, whereas long-standing symptoms partially improved. Short-term shunt complications (n = 2; insufficient catheter placement and subdural hygroma) and a need for long-term stent revisions (n = 3; stent retraction and shunt revision for other causes) were observed. The mean fourth ventricular volume was reduced after surgery (44.2 ± 25.8 to 23.1 ± 21.9 mL; P < .01). Pontine diameter increased from 0.9 ± 0.3 to 1.2 ± 0.3 cm (P < .01) after surgery. Both effects were still demonstrated on later radiological follow-up of 24.4 ± 14.2 months (fourth ventricular size, 24.7 ± 28.1 mL; P < .01; pontine diameter, 1.3 ± 0.3 cm; P < .01).

CONCLUSION: The clinical and radiological outcomes after endoscopic aqueductoplasty and interventriculostomy in children with an isolated fourth ventricle indicate that this procedure is feasible, effective, and safe.

Posted on

Intraoperative Visualization of Fiber Tracking Based Reconstruction of Language Pathways in Glioma Surgery

Neurosurgery 70:911–920, 2012 DOI: 10.1227/NEU.0b013e318237a807 

For neuroepithelial tumors, the surgical goal is maximum resection with preservation of neurological function. This is contributed to by intraoperative magnetic resonance imaging (iMRI) combined with multimodal navigation.

OBJECTIVE: We evaluated the contribution of diffusion tensor imaging (DTI)-based fiber tracking of language pathways with 2 different algorithms (tensor deflection, connectivity analysis [CA]) integrated in the navigation on the surgical outcome.

METHODS: We evaluated 32 patients with neuroepithelial tumors who underwent surgery with DTI-based fiber tracking of language pathways integrated in neuronavigation. The tensor deflection algorithm was routinely used and its results intraoperatively displayed in all cases. The CA algorithm was furthermore evaluated in 23 cases. Volumetric assessment was performed in pre- and intraoperative MR images. To evaluate the benefit of fiber tractography, language deficits were evaluated pre- and postoperatively and compared with the volumetric analysis.

RESULTS: Final gross-total resection was performed in 40.6% of patients. Absolute tumor volume was reduced from 55.33 ± 63.77 cm3 to 20.61 ± 21.67 cm3 in first iMRI resection control, to finally 11.56 ± 21.92 cm3 (P < .01). Fiber tracking of the 2 algorithms showed a deviation of the displayed 3D objects by <5 mm. In long-term followup only 1 patient (3.1%) had a persistent language deficit.

CONCLUSION: Intraoperative visualization of language-related cortical areas and the connecting pathways with DTI-based fiber tracking can be successfully performed and integrated in the navigation system. In a setting of intraoperative high-field MRI this contributes to maximum tumor resection with low postoperative morbidity.

Posted on

Can Elderly Patients Recover Adequately After Laminoplasty?

Spine 2012 ; 37 : 667 – 671 

This was a prospective clinical comparative study of surgical outcomes for patients with cervical spondylotic myelopathy (CSM).

Objective. The purpose of this study was to compare the surgical outcomes between nonelderly and elderly patients with CSM who underwent laminoplasty.

Summary of Background Data. Age at the time of surgery influences the surgical outcome. We designed a large-scale study of the surgical outcome for CSM from a single operative procedure used exclusively in elderly patients.

Methods. A total of 520 consecutive patients with CSM (331 men; 189 women) who underwent double-door laminoplasty were included. Mean age was 62 years (range, 23–93), and mean duration of disease was 20.1 ± 32.0 months. Average postoperative followup period was 33.3 ± 15.7 months. Patients were divided into 3 groups by age: nonelderly ( < 65 years), young-old (65–74 years), and old-old ( ≥ 75 years). The number of patients in each group was 287, 143, and 90. Pre- and postoperative neurological status was evaluated using the Japanese Orthopaedic Association scoring system for cervical myelopathy (JOA score).

Results. Mean pre- and postoperative JOA scores in nonelderly, young-old, and old-old groups were 11.0 and 14.4, 10.2 and 13.2, and 8.7 and 11.8 points, respectively. The elderly group showed significantly low recovery rates of JOA scores compared with the nonelderly group ( P < 0.0001). However, mean achieved JOA scores (postoperative JOA score − preoperative JOA score) were 3.4, 3.0, and 3.1 in nonelderly, young-old, and old-old groups, respectively, with no significant difference among these groups ( P = 0.17).

Conclusion. Pre- and postoperative JOA scores were low in elderly patients. However, the achieved JOA score was almost similar among the 3 groups. Thus, elderly patients could obtain reasonable recovery after cervical laminoplasty.

Posted on

Dichotomy between bifurcation and sidewall aneurysms

J Neurosurg 116:871–881, 2012. http://thejns.org/doi/abs/10.3171/2011.11.JNS11311

Prediction of aneurysm rupture likelihood is clinically valuable, given that more unruptured aneurysms are being discovered incidentally with the increased use of imaging. The authors set out to evaluate the relative performance of morphological features for rupture status discrimination in the context of the divergent geometrical and hemodynamic characteristics of sidewall- and bifurcation-type aneurysms.

Methods. Catheter 3D rotational angiographic images of 271 consecutive aneurysms (101 ruptured, 135 bifurcation type) were used to assess the following parameters in 3D: maximum diameter (Dmax), height, height/width ratio, aspect ratio, size ratio, nonsphericity index, and inflow angle. Univariate statistics applied to the bifurcation, sidewall, and combined (bifurcation + sidewall) sets identified significant features for inclusion in multivariate analysis yielding area under the curve (AUC) and optimal thresholds in the receiver-operating characteristic. Furthermore, a computational fluid dynamics analysis was performed to evaluate the flow and wall shear stress conditions inside sidewall and bifurcation aneurysms at different inflow angles.

Results. The mean Dmax, height, and inflow angle were significantly greater in ruptured sidewall aneurysms than in unruptured sidewall aneurysms, but showed no difference between ruptured and unruptured bifurcation lesions. There was a statistically significant difference between ruptured and unruptured aneurysms for all measured features in the combined set. Multivariate analysis identified the following: 1) nonsphericity index as the only rupture status discriminator in bifurcation lesions (AUC = 0.67); 2) height/width ratio, size ratio, and inflow angle as strong discriminators in sidewall lesions (AUC = 0.87); and 3) height/width ratio, inflow angle, and size ratio as intermediate discriminators in the combined group (AUC = 0.76). Computational fluid dynamics analysis showed that although increasing inflow angle in a sidewall model led to deeper penetration of flow, higher velocities, and higher wall shear stress inside the aneurysm dome, it produced the exact opposite results in a bifurcation model.

Conclusions. Retrospective morphological and hemodynamic analysis point to a dichotomy between sidewall and bifurcation aneurysms with respect to performance of shape and size parameters in identifying rupture status, suggesting the need for aneurysm type–based analyses in future studies. The current most commonly used clinical risk assessment metric, Dmax, was found to be of no value in differentiating between ruptured and unruptured bifurcation aneurysms.

Posted on

Extended transsphenoidal approach for tuberculum sellae meningioma

Acta Neurochir (2012) 154:621–626. DOI 10.1007/s00701-011-1266-0

Recent advances in minimally invasive surgery have allowed extended transsphenoidal approaches to treat large and complex lesions beyond the sella turcica including basal meningiomas, but the inclusion criteria and limitations of this approach remain unclear.

Methods Retrospective review of 19 consecutive patients (5 males and 14 females aged from 43 to 79 years) with tuberculum sellae meningioma with a maximum diameter of less than 30 mm surgically treated between December 2006 and August 2011 by a single surgeon. Operative outcomes and limitation-based indications were investigated. Findings Total removal was achieved in 15 cases including Simpson’s grade 1 in 2 cases (78.9%). All tumor remnants were located in the lateral portion of the internal carotid artery (ICA), as indicated by preoperative magnetic resonance (MR) imaging. Additional oblique imaging along the longitudinal axis of the C1-2 portion of the ICA revealed a paradoxical presence of tumor in between both sides of the ICA in some patients, even in the case with lateral extension over the ICA on coronal MR imaging. Total removal could be achieved in these patients, and after the introduction of additional preoperative oblique MR imaging, total removal was achieved in all patients. Visual outcomes of eyes showed improvement in 23, remained steady in 11, and showed deterioration in 4, and 89.5% eyes recovered to a good state. Deterioration was caused by injury of a small vein in one patient and previous disruption of the arachnoidal sheath in the remaining three. One patient suffered cerebrospinal fluid leakage and required re-operation. None of the patients developed endocrinological deficits or required prolonged hormonal supplementation.

Conclusions The extended transsphenoidal approach has equivalent potential to transcranial surgery for tuberculum sellae meningiomas with a maximum diameter of less than 30 mm. The tumors with lateral extension over the ICA have fewer chances of total removal. ICA-oriented simulation and surgical planning are important.

Posted on

Incremental Contribution of Size Ratio as a Discriminant for Rupture Status in Cerebral Aneurysms: Comparison With Size, Height, and Vessel Diameter

Neurosurgery 70:944–952, 2012 DOI: 10.1227/NEU.0b013e31823bcda7

Aneurysm size ratio (SR), variably defined as the ratio of dome height (H) or maximal dimension (Dmax) over average parent vessel diameter (PV) diameter, has been proposed as a promising aneurysm rupture status predictor.

OBJECTIVE: To evaluate the incremental contribution of SR to retrospective rupture status determination in a large high-resolution aneurysm database.

METHODS: Measurements were performed on catheter 3D-rotational angiographic volumetric datasets for 267 aneurysms (98 ruptured). SR was computed both as H/PV (SR1) and as Dmax/PV (SR2), and its discriminant performance was evaluated on the whole dataset, on aneurysm-type subsets (bifurcation [BIF] vs sidewall [SW]), and at specific aneurysm locations. Univariate and multivariate statistical analyses were performed by the use of area under the curve (AUC) of the receiver-operating characteristics.

RESULTS: Neither SR1 nor SR2 were statistically correlated to rupture status in the BIF group, where only PV (AUC = 0.61) achieved significance. All parameters were statistically significant in the combined group, but with modest performance (AUC range, 0.62- 0.74). SR1 (AUC = 0.84) and SR2 (AUC = 0.78) were strong predictors in the SW group, similar to H (AUC = 0.83) and Dmax (AUC = 0.77). Multivariate statistics failed to support SR as an incremental independent parameter from PV, Dmax, and H.

CONCLUSION: SR provides an uneven performance that depends strongly on the BIF/ SW distribution of the data and is not useful for bifurcation lesions. In the SW subset, the incremental contribution of the SR over its H or Dmax individual component measurements could not be validated, suggesting prior findings of its utility to be the result of aneurysm-type selection bias.

Posted on

Clinical Assessment of Percutaneous Lumbar Pedicle Screw Placement Using the O-Arm Multidimensional Surgical Imaging System

Neurosurgery 70:990–995, 2012 DOI: 10.1227/NEU.0b013e318237a829

Increasing popularity of minimally invasive surgery for lumbar fusion has led to dependence upon intraoperative fluoroscopy for pedicle screw placement, because limited muscle dissection does not expose the bony anatomy necessary for traditional, freehand techniques nor for registration steps in image-guidance techniques. This has raised concerns about cumulative radiation exposure for both surgeon and operating room staff. The recent introduction of the O-arm Multidimensional Surgical Imaging System allows for percutaneous placement of pedicle screws, but there is limited clinical experience with the technique and data examining its accuracy.

OBJECTIVE: We present the first large clinical series of percutaneous screw placement using navigation of O-arm imaging and compare the results with the fluoroscopyguided method.

METHODS: A retrospective review of a 24-month period identified patients undergoing minimally invasive lumbar interbody fusion. The O-arm was introduced in the middle of this period and was used for all subsequent patients. Accuracy of screw placement was assessed by examination of axial computed tomography or O-arm scans.

RESULTS: The fluoroscopy group included 141 screws in 42 patients, and the O-arm group included 205 screws in 52 patients. The perforation rate was 12.8% in the fluoroscopy group and 3% in the O-arm group (P < .001). Single-level O-arm procedures took a mean 200 (153-241) minutes, whereas fluoroscopy took 221 (178-302) minutes (P < .03).

CONCLUSION: Percutaneous pedicle screw placement with the O-arm Multidimensional Intraoperative Imaging System is a safe and effective technique and provided improved overall accuracy and reduced operative time compared with conventional fluoroscopic techniques.

Posted on

Complications of endoscopic microdiscectomy using the EASYGO! system

Acta Neurochir DOI 10.1007/s00701-012-1321-5.

Microendoscopic discectomy (MED) is emerging as a minimally invasive alternative to conventional microsurgical discectomy (MSD). EASYGO! is a new system for spinal endoscopy that claims smooth transition from MSD to MED, with a reduced learning curve period. The aims of this study were to describe the complications that appeared during the learning curve period of MED and to compare their incidence with the rate and type of complications that occurred during a simultaneous non-randomised series of standard MSDs.

Methods Between July 2009 and December 2010, 138 patients underwent scheduled first-time discectomy in our institution, 37 using an MED approach and 101 by a conventional MSD. A MED learning curve was obtained by plotting every case with its respective operative time. Complications, length of hospital stay, need of further surgery and outcome were prospectively recorded in both groups.

Results The mean operative time was 66 min for the MSD group and 100 min for the MED group, although for the last 14 cases of the latter group the time was reduced. Curvefitting techniques showed that the inverse equation, ƒ(x)= 122.12/x+73.05, had the best correlation between case number and operative time. The learning curve was overcome after the 30th case. Complications occurred in 9.8 % of the MSD group and 8.1 % of the MED group (P=0.49). Average length of hospital stay was 2.36 days for the MED group and 3.36 days for the MSD group (P=0.01). The procedure successfully relieved patient symptoms in 68.63 % of the MSD group and 89.92 % of the MED group. No revision surgery was required in the MED group, but it was necessary in ten patients of the MSD group.

Conclusions Between 25 and 30 cases are needed to reach the learning curve’s asymptote of MED. Even during this initial learning period MED is a safe procedure, with comparable results to those obtained with conventional MSD and with a similar complication rate. The key points for reducing intraoperative complications are an adequate expertise in MSD, a precise selection of initial cases, a proper surgical planning and a careful technique, which are mandatory to avoid unnecessary neurological injury in an otherwise secure surgical approach.

Posted on

Thalamic and Subthalamic Deep Brain Stimulation for Essential Tremor: Where Is the Optimal Target?

Neurosurgery 70:840–846, 2012 DOI: 10.1227/NEU.0b013e318236a809

The ventrolateral thalamus (ventral intermediate nucleus [Vim]) is the traditional target for neurosurgical treatment of essential tremor. The target, however, has varied substantially among different neurosurgeons.

OBJECTIVE: To evaluate the effect of deep brain stimulation in the thalamus and posterior subthalamic area (PSA) in relation to electrode location.

METHODS: Thirty-six (17 Vim/19 PSA) patients with 44 deep brain stimulation electrodes were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the Essential Tremor Rating Scale.

RESULTS: When each contact was evaluated in terms of the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was located in the zona incerta or radiation prelemniscalis in 54% and the Vim in 12%. Forty contacts provided a tremor reduction of . 90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrand atlas. Of these 40 contacts, 37 were found in the PSA group.

CONCLUSION: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated on in the Vim got the best effect from a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

Posted on

Supracerebellar transtentorial approach—resection of the tentorium instead of an opening—to provide broad exposure of the mediobasal temporal lobe: anatomical aspects and surgical applications

J Neurosurg 116:764–772, 2012.  http://thejns.org/doi/abs/10.3171/2011.12.JNS111256

The aim of this study was to describe the surgical anatomy of the mediobasal aspect of the temporal lobe and the supracerebellar transtentorial (SCTT) approach performed not with an opening, but with the resection of the tentorium, as an alternative route for the neurosurgical management of vascular and tumoral lesions arising from this region.

Methods. Cadaveric specimens were used to illustrate the surgical anatomy of the mediobasal region of the temporal lobe. Demographic aspects, characteristics of lesions, clinical presentation, surgical results, follow-up findings, and outcomes were retrospectively reviewed for patients referred to receive the SCTT approach with tentorial resection.

Results. Ten patients (83%) were female and 2 (17%) were male. Their ages ranged from 6 to 59 years (mean 34.5 ± 15.8 years). All lesions (3 posterior cerebral artery aneurysms, 3 arteriovenous malformations, 3 cavernous malformations, and 3 tumors) were completely excluded or resected. After a mean follow-up period of 143 months (range 10–240 months), the mean postoperative Glasgow Outcome Scale score was 4.9.

Conclusions. Knowledge of the surgical anatomy provides improvement for microsurgical approaches. The evolution from a small opening to a resection of the tentorium absolutely changed the exposure of the mediobasal aspect of the temporal lobe. The SCTT approach with tentorial resection is an excellent alternative route to the posterior part of mediobasal aspect of the temporal lobe, and it was enough to achieve the best neurosurgical management of tumoral and vascular lesions located in this area.

Posted on

Oxiplex Reduces Leg Pain, Back Pain, and Associated Symptoms After Lumbar Discectomy

SPINE Volume 37, Number 8, pp 631–641

Study Design. Prospective, randomized, blinded clinical trial.

Objective. To evaluate effectiveness of Oxiplex gel for reduction of pain and associated symptoms after lumbar discectomy.

Summary of Background Data. Oxiplex gel (carboxymethylcellulose, polyethylene oxide, and calcium) is used during discectomy to coat the surgical site for reduction of pain and symptoms after lumbar discectomy.

Methods. Patients undergoing single-level lumbar discectomy performed by laminectomy or laminotomy and randomized to receive either surgery plus Oxiplex gel (treatment group) or surgery alone (control group) were assessed 6 months after surgery using (1) a quality of life questionnaire (Lumbar Spine Outcomes Questionnaire [LSOQ]) and (2) clinical evaluations.

Results. There were no statistically significant differences in baseline demographics, surgical procedures, LSOQ scores, and clinical evaluations between treatment (N = 177) and control (N = 175) groups. More gel-treated patients were satisfied with outcome of their surgical treatment than control patients ( P = 0.05). The geltreated group showed greater reductions in pain and symptoms from baseline compared with surgery-only controls. Additional benefits of gel were consistently shown in reduction of leg and back pain at 6 months in the patient population having substantial back  pain at baseline (greater than or equal to the median LSOQ pain score of 63). In that population, there was a statistically signifi cant reduction of leg pain and back pain ( P < 0.01) in the treatment group compared with controls. Fewer patients in the treatment group had abnormal musculoskeletal physical examinations at 6 months compared with controls. There were no cases of cerebrospinal fluid leaks and no differences in laboratory values or vital signs. Patients in the treatment group had less hypoesthesia, paraesthesia, sensory loss, and fewer reoperations during the 6-month follow-up than controls (1 vs . 6).

Conclusion. These data demonstrate improvements in clinical  outcomes resulting from the use of Oxiplex gel in discectomy procedures for treatment of lumbar disc herniation.

Posted on

Jugular foramen paragangliomas: management, outcome and avoidance of complications in a series of 75 cases

Neurosurg Rev (2012) 35:185–194. DOI 10.1007/s10143-011-0346-1

Jugular foramen paragangliomas are rare skull base tumours posing multiple complex diagnostic and management problems. We did a study to evaluate surgical technique, outcome and complications in 75 cases of tumours treated by multidisciplinary approach (i.e. combined neurosurgery, neuroradiology, ear, nose and throat surgery and intensive care unit team).
Methods: Retrospective study on 75 consecutive patients with jugular foramen paragangliomas treated surgically from 1989 to 2005. Preoperative balloon occlusion test was performed in all patients as well as embolization (100%). A combined limited infratemporal and juxtacondylar approach was used in all patients.
Results: Gross total resection was achieved in 59 patients (78.7%). The most common complication was represented by lower cranial nerve deficits in five patients (6.6%), which was only temporary in three. Postoperative facial nerve weakness occurred in five cases (6.6%) and resolved in three of them. The remaining two patients underwent facial nerve reconstruction by hypoglossal/facial nerve anastomosis. Four patients (5.3%) had a postoperative cerebrospinal fluid leak, which was successfully treated by lumbar drainage. Two patients (2.7%) died because of complications related to surgical injury of lower cranial nerves: one patient developed aspiration pneumonia and septicemia and the second one developed a large cervicobulbar hematoma that led to severe respiratory distress and ultimately global cerebral hypoxia.
Conclusion: Paragangliomas are rare and complex skull base lesions that may be managed with low morbidity and mortality if a multidisciplinary approach is considered. Facial and lower cranial nerve postoperative deficits can be limited.

Posted on

Awake surgery for incidental WHO grade II gliomas involving eloquent areas

Acta Neurochir (2012) 154:575–584.DOI 10.1007/s00701-011-1216-x
WHO grade II glioma (G2G) is a premalignant tumor, usually revealed by seizures in young patients living normal lives. G2G grows constantly and will inevitably become anaplastic. Surgical resection significantly increases the overall survival by delaying malignant transformation. Recently, a similar natural history was demonstrated in a patient with incidental G2G, with continuous growth and risk of anaplasia. Here, the aim was to study for the first time the functional results and extent of resection in a prospective series of patients who underwent resection for incidental G2G within eloquent areas.
Method G2G involving functional regions in the left dominant hemisphere was incidentally diagnosed in 11 asymptomatic patients. Resection was achieved in all cases after demonstration of a volumetric increase on serial MRIs. Intraoperative awake mapping was performed in the 11 patients.
Findings There were no cases of mortality or permanent postoperative deficit. A subtotal, total or even “supratotal” resection was achieved in the 11 cases, with no partial resections. All patients resumed normal social and professional lives, with no seizures (KPS 100). Due to slow tumor re-growth in three patients with subtotal resection, adjuvant chemotherapy was administrated in two cases and radiotherapy in one. With a mean follow-up of 40 months since surgery, there was no anaplastic transformation.
Conclusion These results show that surgery can be considered in incidental G2G, even in critical areas, with a minimal risk and optimal resection, thanks to intraoperative mapping. Such findings raise the question of an early detection.

Posted on

Minimally invasive treatment for intracerebral hemorrhage

Neurosurg Focus 32 (4):E3, 2012. http://thejns.org/doi/abs/10.3171/2012.1.FOCUS11362

Spontaneous intracerebral hemorrhage is a serious public health problem and is fatal in 30%–50% of all occurrences. The role of open surgical management of supratentorial intracerebral hemorrhage is still unresolved. A recent consensus conference sponsored by the National Institutes of Health suggests that minimally invasive techniques to evacuate clots appear to be a promising area and warrant further investigation. In this paper the authors review past, current, and potential future methods of treating intraparenchymal hemorrhages with minimally invasive techniques and review new data regarding the role of stereotactically placed catheters and thrombolytics.

A minimally invasive approach to evacuate ICH has been well documented to be a safe practice. Thus far, the CLEAR and MISTIE studies have supported this assertion. An increased rate of clot lysis could potentially be achieved with a combination of mechanical and pharmaceutical approaches. However, more extensive studies need to be conducted to determine whether the additional mechanical effects via ultrasound further yield beneficial long-term outcome versus pharmacological lysis alone. Currently, catheters are being redesigned for this purpose and will be evaluated in additional future clinical trials.

Posted on

Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging


 

J Neurosurg 116:697–702, 2012. http://thejns.org/doi/abs/10.3171/2011.12.JNS111404

Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings.

Methods. The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings.

Results. Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients.

Conclusions. The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

Posted on

Cervical Laminectomy vs Laminoplasty: Is There a Difference in Outcome and Postoperative Pain?

Neurosurgery 70:965–970, 2012 DOI: 10.1227/NEU.0b013e31823cf16b 

Cervical laminoplasty is often used for the decompression of multilevel cervical spondylotic myelopathy without creating spinal instability and kyphosis.

OBJECTIVE: To assess the axial pain, quality of life, sagittal alignment, and extent of decompression after standard cervical laminectomy or laminoplasty. We further evaluate whether the sagittal alignment changes over time after both procedures and whether axial pain depends on sagittal alignment.

METHODS: We reviewed 268 patients with cervical radiculopathy or myelopathy who had undergone standard cervical laminectomy or laminoplasty between January 1999 and January 2009. The clinical outcome was analyzed by visual analog scale for neck pain. The quality of life was analyzed by EQ-5D questionnaire. The degree of deformity and extent of decompression were assessed using the Ishihara index and Pavlov’s ratio, respectively.

RESULTS: Laminoplasty was associated with more neck pain and worse quality of life when 4 or more levels were decompressed compared with the laminectomy group. For operations of 3 or fewer levels, there was no difference. Interestingly, the radiological effectiveness of decompression was greater in the laminoplasty group.

CONCLUSION: Laminoplasty for 4 or more cervical levels was associated with more axial pain and consequently poorer quality of life than laminectomy. There was a similar loss of sagittal alignment in both the laminectomy and laminoplasty groups over time. Our results suggest there is no clear benefit of laminoplasty over laminectomy in patients who do not have spinal instability.

Posted on

5-Aminolevulinic acid-induced protoporphyrin IX fluorescence as immediate intraoperative indicator to improve the safety of malignant or high-grade brain tumor diagnosis in frameless stereotactic biopsies

Acta Neurochir (2012) 154:585–588. DOI 10.1007/s00701-012-1290-8

Frameless stereotactic biopsies are replacing frame-based stereotaxy as a diagnostic approach to brain lesions. In order to avoid a sampling bias or negative histology, multiple specimens are often taken. This in turn increases the risk of hemorrhagic complications.

Objective We present the use of 5-aminolevulinic acid (5- ALA)-induced protoporphyrin IX fluorescence in frameless stereotaxy to improve the procedure duration and yield, and thereby reduce the risk of complications.

Methods Patients with suspected high-grade brain tumors are given 5-ALA 4 h prior to stereotactic biopsy. The biopsy needle is guided to the target using frameless stereotaxy based either on preoperative images or combined with intraoperative MRI sequences. The specimen is illuminated with blue light to look for fluorescence. In case of a positive fluorescence within the tissue sample, no frozen sections are obtained, and no further specimens are taken.

Results The samples of 13 patients revealed a positive fluorescence and were histologically confirmed as malignant or high-grade brain neoplasms. four cases were fluorescence-negative, requiring frozen section confirmation and/or multiple samples. In theses cases histology was either nonspecific gliotic changes or low-grade tumors. There were no complications related to the additional use of 5-ALA.

Conclusion 5-ALA fluorescence in stereotactic biopsies can increase the safety and accuracy of these procedures by reducing sampling errors and eliminating the need for multiple samples and/or frozen section verification, creating a more accurate, faster and safer procedure for cases of suspected malignant or high-grade brain tumors situated in deep or eloquent areas.

Posted on

Analysis of the uncinate processes of the cervical spine

J Neurosurg Spine 16:402–407, 2012. http://thejns.org/doi/abs/10.3171/2011.12.SPINE11541

Although the uncovertebral region is neurosurgically relevant, relatively little is reported in the literature, specifically the neurosurgical literature, regarding its anatomy. Therefore, the present study aimed at further elucidation of this region’s morphological features.

Methods. Morphometry was performed on the uncinate processes of 40 adult human skeletons. Additionally, range of motion testing was performed, with special attention given to the uncinate processes. Finally, these excrescences were classified based on their encroachment on the adjacent intervertebral foramen.

Results. The height of these processes was on average 4.8 mm, and there was an inverse relationship between height of the uncinate process and the size of the intervertebral foramen. Degeneration of the vertebral body (VB) did not correlate with whether the uncinate process effaced the intervertebral foramen. The taller uncinate processes tended to be located below C-3 vertebral levels, and their average anteroposterior length was 8 mm. The average thickness was found to be 4.9 mm for the base and 1.8 mm for the apex. There were no significant differences found between vertebral level and thickness of the uncinate process. Arthritic changes of the cervical VBs did not necessarily deform the uncinate processes. With axial rotation, the intervertebral discs were noted to be driven into the ipsilateral uncinate process. With lateral flexion, the ipsilateral uncinate processes aided the ipsilateral facet joints in maintaining the integrity of the ipsilateral intervertebral foramen.

Conclusions. A good appreciation for the anatomy of the uncinate processes is important to the neurosurgeon who operates on the spine. It is hoped that the data presented herein will decrease complications during surgical approaches to the cervical spine.

Posted on

Injuries of the Cingulum and Fornix After Rupture of an Anterior Communicating Artery Aneurysm

Neurosurgery 70:819–823, 2012 DOI: 10.1227/NEU.0b013e3182367124 

After rupture of an anterior communicating artery (ACoA) aneurysm, the anterior cingulum and the fornix can be vulnerable to injury. However, very little is known about this topic.

OBJECTIVE: To investigate injuries of the cingulum and fornix in patients with an ACoA aneurysm rupture with diffusion tensor tractography.

METHODS: Eleven consecutive patients with an ACoA aneurysm rupture and 11 ageand sex-matched normal control subjects were recruited. Diffusion tensor imaging was scanned at an average of 54.1 days (range, 29-97 days) after onset of ACoA aneurysm rupture.

RESULTS: We found that 6 (54.5%) and 7 (63.6%) of 11 patients revealed no trajectory of the anterior cingulum and the fornical body on diffusion tensor tractography, respectively. In terms of diffusion tensor imaging parameters, we found that the fractional anisotropy value and tract volume of the cingulum and fornix were decreased (P , .05) and that mean diffusivity values were increased (P , .05), except for those of the left fornix, which showed no difference (P . .05).

CONCLUSION: We found injuries of the cingulum and fornix in patients with an ACoA aneurysm rupture. It is our belief that sustained memory impairment of patients with an ACoA aneurysm rupture might be related to injury of the cingulum and fornix. Therefore, we recommend evaluation of the cingulum and fornix with diffusion tensor tractography for patients with an ACoA aneurysm rupture.

Posted on

The paramedian supracerebellar-transtentorial approach to the entire length of the mediobasal temporal region

J Neurosurg 116:773–791, 2012. http://thejns.org/doi/abs/10.3171/2011.12.JNS11791

The exploration of lesions in the mediobasal temporal region (MTR) has challenged generations of neurosurgeons to achieve an appropriate approach. To address this challenge, the extensive use of the paramedian supracerebellar-transtentorial (PST) approach to expose the entire length of the MTR, as well as the fusiform gyrus, was investigated.

Methods. The authors studied the microsurgical aspects of the PST approach in 20 cadaver brains and 5 cadaver heads under the operating microscope. They evaluated the features, advantages, difficulties, and limitations of the PST approach and refined the surgical technique. They then used the PST approach in 15 patients with large intrinsic MTR tumors (6 patients), tumor in the posterior fusiform gyrus with mediobasal temporal epilepsy (MTE) (1 patient), cavernous malformations in the posterior MTR including the fusiform gyrus (2 patients), or intractable MTE with hippocampal sclerosis (6 patients) from December 2007 to May 2010. Patients ranged in age from 11 to 63 years (mean 35.2 years), and in 9 patients (60%) the lesion was located on the left side.

Results. In all patients with neuroepithelial tumors or cavernous malformations, the lesions were completely and safely resected. In all patients with intractable MTE with hippocampal sclerosis, the anterior two-thirds of the parahippocampal gyrus and hippocampus, as well as the amygdala, were removed selectively through the PST approach. There was no surgical morbidity or mortality in this series. Three patients (20%) with high-grade neuroepithelial tumors underwent postoperative radiotherapy and chemotherapy but needed a second surgery for recurrence during the follow-up period. In all patients with MTE, antiepileptic medication could be decreased to a single drug at lower doses, and no seizure activity has occurred until this point.

Conclusions. The PST approach provides the surgeon precise anatomical orientation when exposing the entire length of the MTR, as well as the fusiform gyrus, for removing any lesion. This is a novel technique especially for removing tumors involving the entire MTR in a single session without damaging neighboring neural or vascular structures. This approach can also be a viable alternative for selective removal of the parahippocampal gyrus, hippocampus, and amygdala in patients with MTE due to hippocampal sclerosis.

Proudly powered by WordPress