Neurosurgery Blog

J Neurosurg 113:486–492, 2010.DOI: 10.3171/2010.1.JNS091106

The aim of this study was to compare percutaneous balloon compression (PBC) and percutaneous retrogasserian glycerol rhizotomy (PRGR) in terms of effectiveness, complications, and technical aspects.

Methods. Sixty-six consecutive PBC procedures were performed in 45 patients between January 2004 and December 2008, and 120 PRGR attempts were performed in 101 patients between January 2006 and December 2008. The PRGR procedures were not completed due to technical reasons in 19 cases. Five patients in the Balloon Compression Group and 9 patients in the Glycerol Group were lost to follow-up and were excluded from the study. The medical records and the intraoperative fluoroscopic images from the remaining cases were retrospectively examined, and the follow-up was completed with telephone contact, when necessary. The 2 groups were compared in terms of initial effect, duration of effect, and rates of complications as well as severity and type of complications.

Results. The rates for immediate pain relief were 87% for patients treated with glycerol injection and 85% for patients treated with balloon compression. The Kaplan-Meier plots for the 2 treatment modalities were similar. The 50% recurrence time was 21 months for the balloon procedure and 16 months for the glycerol procedure. When the groups were broken down by the “previous operations” criterion, the 50% recurrence time was 24 months for the Glycerol First Procedure Group, 6 months for the Balloon First Procedure Group, 8 months for the Glycerol Previous Procedures Group, and 21 months for the Balloon Previous Procedures Group. The rates of complications (excluding numbness) were 11% for PRGR and 23% for PBC, and this difference was statistically significant (chi-square test, p = 0.04).

Conclusions. Both PRGR and PBC are effective techniques for the treatment of trigeminal neuralgia, with PRGR presenting some advantages in terms of milder and fewer complications and allowing lighter anesthesia without compromise of analgesia. For these reasons the authors consider PRGR as the first option for the treatment of trigeminal neuralgia in patients who are not suitable candidates or are not willing to undergo microvascular decompression, while PBC is reserved for patients in whom the effect of PRGR has proven to be short or difficult to repeat due to cisternal fibrosis.

Neurosurg Focus 29 (2):E13, 2010. DOI: 10.3171/2010.5.FOCUS1094

The aim of this study was to review the indications for and results of deep brain stimulation (DBS) of the posterior hypothalamus (pHyp) in the treatment of drug-refractory and severe painful syndromes of the face, disruptive and aggressive behavior associated with epilepsy, and below-average intelligence. The preoperative clinical picture, functional imaging studies, and overall clinical results in the literature are discussed.

Methods. All patients underwent stereotactic implantation of deep-brain electrodes within the pHyp. Data from several authors have been collected and reported for each clinical entity, as have clinical results, adverse events, and neurophysiological characteristics of the pHyp.

Results. The percentage of patients with chronic cluster headache who responded to DBS was 50% in the overall reported series. The response rate was 100% for short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and for chronic paroxysmal hemicrania, although only 2 patients and 1 patient, respectively, have been described as having these conditions. None of the 4 patients suffering from refractory neuropathic trigeminal pain benefited from the procedure (0% response rate), whereas all 5 patients (100%) affected with refractory trigeminal neuralgia (TN) due to multiple sclerosis (MS) and undergoing pHyp DBS experienced a significant decrease in pain attacks within the first branch of cranial nerve V. Six (75%) of 8 patients presenting with aggressive behavior and mental retardation benefited from pHyp stimulation; 6 patients were part of the authors’ series and 2 were reported in the literature.

Conclusions. In carefully selected patients, DBS of the pHyp can be considered an effective procedure for the treatment of refractory trigeminal autonomic cephalalgias, aggressive behavior, and MS-related TN in the first trigeminal branch. Only larger and prospective studies along with multidisciplinary approaches (including, by necessity, neuroimaging studies) can lead us to better patient selection that would reduce the rate of nonresponders.

J Neurosurg 113:53–58, 2010. (DOI: 10.3171/2009.9.JNS09196)

Trigeminal neuralgia is believed to be related to vascular compression of the affected nerve. Radiosurgery has been shown to be reasonably effective for treatment of medically refractory trigeminal neuralgia. This study explores the rate of occurrence of MR imaging–demonstrated vascular impingement of the affected nerve and the extent to which vascular impingement affects pain relief in a population of trigeminal neuralgia patients undergoing Gamma Knife radiosurgery (GKRS).

Methods. The authors performed a retrospective analysis of 106 cases involving patients treated for typical trigeminal neuralgia using GKRS. Patients with or without single-vessel impingement on CISS MR imaging sequences and with no previous surgery were included in the study. Pain relief was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at the last follow-up. Degree of impingement, nerve diameter preand post-impingement, isocenter placement, and dose to the point of maximum impingement were evaluated in relation to the improvement of BNI score.

Results. The overall median follow-up period was 31 months. Overall, a BNI pain score of 1 was achieved in 59.4% of patients at last follow-up. Vessel impingement was seen in 63 patients (59%). There was no significant difference in pain relief between those with and without vascular impingement following GKRS (p > 0.05). In those with vascular impingement on MR imaging, the median fraction of vessel impingement was 0.3 (range 0.04–0.59). The median dose to the site of maximum impingement was 42 Gy (range 2.9–79 Gy). Increased dose (p = 0.019) and closer proximity of the isocenter to the site of maximum vessel impingement (p = 0.012) correlated in a statistically significant fashion with improved BNI scores in those demonstrating vascular impingement on the GKRS planning MR imaging

Conclusions. Vascular impingement of the affected nerve was seen in the majority of patients with trigeminal neuralgia. Overall pain relief following GKRS was comparable in those with and without evidence of vascular compression on MR imaging. In subgroup analysis of those with MR imaging evidence of vessel impingement of the affected trigeminal nerve, pain relief correlated with a higher dose to the point of contact between the impinging vessel and the trigeminal nerve. Such a finding may point to vascular changes affording at least some degree of relief following GKRS for trigeminal neuralgia.

Acta Neurochir (2010) 152:1043–1053. DOI 10.1007/s00701-010-0604-y

Meckel’s Cave may be accessed percutaneously through the foramen ovale (FO). Detailed knowledge of the region’s anatomical surroundings is invaluable in improving target accuracy and preventing complications with this approach. The approach has been used in the treatment of trigeminal neuralgia as well as in performing biopsies of lesions located in the parasellar region, described formerly by the senior author (M.S.). A comprehensive cadaveric study of the region traversed by needle is thus presented.

Materials and methods Three cadaveric heads (six sides) were fixed in formaldehyde and injected with latex. A detailed description of the regional anatomical needle trajectories was performed.

Results An “inverted pyramid” subdivided into three segments is described. The inferior third begins at cutaneous penetration and ends at the parotid duct (PD). The middle third extends from the PD to the lateral pterygoid muscle (LPM). The superior third starts from the LPM and ends at the FO. The main vascular anatomical variation was with regard to the maxillary artery (MA). In half of the cases, the MA traveled though the middle of the pyramid and in the other half through the upper third.

Conclusions Although widely used, the FO approach carries risks. Special attention is warranted when the needle traverses the upper third of the pyramid to avoid the variant course of the MA. Image-guided techniques and detailed anatomical knowledge are necessary to expand the use of this route not just for approach to lesions within the parasellar and upper third of the petroclival region but also to lesions invading the infratemporal fossa.

Acta Neurochir (2010) 152:817–825. DOI 10.1007/s00701-009-0588-7

Surgical outcome after microvascular decompression (MVD) for primary trigeminal neuralgia (TN) has been demonstrated as being related to the characteristics of the neurovascular compression (NVC), especially to the degree of compression exerted on the root. Therefore, preoperative determination of the NVC features could be of great value to the neurosurgeon, for evaluation of conflicting nature, exact localization, direction and degree of compression. This study deals with the predictive value of MRI in detecting and assessing features of vascular compression in 100 consecutive patients who underwent MVD for TN.

Methods. The study included 100 consecutive patients with primary TN who were submitted to a preoperative 3D MRI 1.5 T with T2 high-resolution, TOF-MRA, and T1-Gadolinium. Image analysis was performed by an independent observer blinded to the operative findings and compared with surgical data.

Findings. In 88 cases, image analysis showed NVC features that coincided with surgical findings. There were no false-positive results. Among 12 patients that did not show NVC at image analysis, nine did not have NVC at intraoperative observation, resulting in three false-negative cases. MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9). Image analysis correctly identified compressible vessel in 80 of the 91 cases and degree of compression in 77 of the 91 cases. Kappa-coefficient predicting degree of root compression was 0.746, 0.767, and 0.86, respectively, for Grades I (simple contact), II (distortion), and III (marked indentation; p<0.01).

Conclusion. 3D T2 high-resolution in combination with 3D TOF-MRA and 3D T1-Gadolinium proved to be reliable in detecting NVC and in predicting the degree of the root compression

Eur Spine J (2009) 18:1836–1842DOI 10.1007/s00586-009-1019-4

Tizanidine and aceclofenac individually have shown efficacy in the treatment of low back pain. The efficacy and tolerability of the combination have not yet been established.

The objective of the study was to evaluate the efficacy and safety of aceclofenac-tizanidine fixed dose combination against aceclofenac alone in patients with acute low back pain.

This double-blind, double-dummy, randomized, comparative, multicentric, parallel group study enrolled 197 patients of either sex in the age range of 18–70 years with acute low back pain. The patients were randomized to receive either aceclofenac (100 mg)–tizanidine (2 mg) b.i.d or aceclofenac (100 mg) alone b.i.d for 7 days. The primary efficacy outcomes were pain intensity (on movement, at rest and at night; on VAS scale) and pain relief (on a 5-point verbal rating scale). The secondary efficacy outcomes measures included functional impairment (modified Schober’s test and lateral body bending test) and patient’s and investigator’s global efficacy assessment.

Aceclofenac–tizanidine was significantly superior to aceclofenac for pain intensity (on movement, at rest and at night; P < 0.05) and pain relief (P = 0.00) on days 3 and 7. There was significant increase in spinal flexion in both the groups from baseline on days 3 and 7 with significant difference in favour of the combination group (P < 0.05). There were significantly more number of patients with excellent to good response for the aceclofenac–tizanidine treatment as compared to aceclofenac alone (P = 0.00). Both the treatments were well tolerated.

In this study, aceclofenac–tizanidine combination was more effective than aceclofenac alone and had a favourable safety profile in the treatment of acute low back pain.

REV NEUROL 2009; 49: 630-2

Introduction. The vascular compression of a nerve is known to be the most important cause of idiopathic trigeminal neuralgia (ITN) by most authors. However, several cases of skull base deformities in patients with ITN have been reported in our bibliographic review. Aim. To compare the existence of platybasia between a group of patients with ITN and a randomized control group.

Subjects and methods. Twenty-five patients with ITN and twenty-five control subjects were X-rayed and their basal angles were measured and compared.

Results. The basal angle measured to investigate the existence of platybasia is significantly greater in the ITN group than in the control group. Platybasia was found in 10 patients with ITN. However, only two cases of platybasia were reported in the control group. Therefore in our study we have found that the incidence of platybasia in patients with ITN is significantly increased.

Conclusion. Our data demonstrated that platybasia has an important role in the pathogenesis of the ITN by altering the normal anatomy of the nerves and vessels within the posterior fossa

Journal of Neurosurgery, Dec 2009, Vol. 111, No. 6, Pages 1231-1234. DOI: 10.3171/2008.6.17604
Trigeminal neuralgia (TN) presents a diagnostic challenge because of the variety of symptoms, findings during microvascular decompression (MVD), and postsurgical outcomes observed among patients who suffer from this disorder. Recently, a new paradigm for classification of TN was proposed, based on the quality of pain. This study represents the first clinical analysis of this paradigm.
Methods
The authors analyzed 144 consecutive cases involving patients who underwent MVD for TN. Preoperative symptoms were classified into 1 of 2 categories based on the preponderance of shocklike (Type 1 TN) or constant (Type 2 TN) pain. Analysis of clinical characteristics, neurovascular pathology, and postoperative outcome was performed.
Results
Compared with Type 2 TN, Type 1 TN patients were older, were more likely to have right-sided symptoms, and reported a shorter duration of symptoms prior to evaluation. Previous treatment by percutaneous or radiosurgical procedures was not a predictor of symptoms, surgical findings, or outcome (p = 0.48). Type 1 TN was significantly more likely to be associated with arterial compression. Venous or no compression was more common among Type 2 TN patients (p < 0.01). Type 1 TN patients were also more likely to be pain-free immediately after surgery, and less likely to have a recurrence of pain within 2 years (p < 0.05). Although a subset of patients progressed from Type 1 to Type 2 TN over time, their pathological and prognostic profiles nevertheless resembled those of Type 1 TN.
Conclusions
Type 1 and Type 2 TN represent distinct clinical, pathological, and prognostic entities. Classification of patients according to this paradigm should be helpful to determine how best to treat patients with this disorder.

J Neurosurg 111:359–364, 2009

Trigeminal neuralgia (TN) is a disorder of the trigeminal nerve that results in intense episodic pain. Primary treatment with Gamma Knife surgery (GKS) is well established; however, a significant number of patients experience recurrence of TN over time. Repeat GKS can be performed, but the retreatment dose has not been well established. In this study, the authors present their institutional retreatment results and compare them with other series.

Methods
Between December 2003 and January 2006, 28 patients were treated at Tufts Medical Center with repeat GKS for recurrence of TN. All patients had been initially treated with GKS at this institution, and only those with significant pain improvement were offered retreatment. The maximum dose was prescribed using a single isocenter; the 4-mm collimator was used. The initial median GKS dose was 80 Gy, the median retreatment dose was 45 Gy, and the median cumulative dose was 125 Gy. The median time between GKS procedures was 18.1 months. Facial pain outcomes were defined using the Marseille scale. Excellent outcome was defined as no pain (with or without medications), and good outcome was defined as > 50% pain relief. Toxicity was categorized as none, mild, or bothersome. The median clinical follow-up after the second GKS was 19.7 months. Our clinical outcomes were compared with 8 previously reported retreatment series (including 1 abstract), both for rate of pain control and for rate of complications.

Results
Outcomes after the second GKS were excellent in 29% (8 patients), good in 32% (9), and poor in 39% (11). Four patients (14%) experienced no improvement after repeat GKS. Eight patients (29%) experienced new trigeminal nerve dysfunction, including numbness (11%), paresthesia (14%), dysesthesia (4%), taste alteration (11%), and bite weakness (4%). None of these were bothersome. No patient developed corneal numbness. Univariate analysis failed to reveal any significant predictors of pain control or complications.

Seven published peer-reviewed retreatment series and the authors’ data (total 215 patients) were analyzed. There was a cumulative dose-response relationship for both pain control (p = 0.04) and new trigeminal dysfunction (p = 0.08). Successful pain control was strongly correlated with development of new dysfunction (p = 0.02). A cumulative dose > 130 Gy was more likely to result in successful (> 50%) pain control, but was also more likely (> 20%) to result in development of new dysfunction.

Conclusions
Successful retreatment of patients in whom the initial GKS treatment fails is feasible. Patients who respond initially may be at a higher risk of retreatment-related complications. There appears to be a dose-response relationship for both pain control and development of new side effects. It is important to counsel and treat patients individually based on this dose-response relationship.

Neuroradiology (2009) 51:563-566