Quantitative evaluation of hippocampal gray-white matter boundary blurring in medial temporal lobe epilepsy with hippocampal sclerosis.

INTRODUCTION: The magnetic resonance imaging (MRI) findings of hippocampal sclerosis (HS) include decreased volume, increased signal intensity, and hippocampal gray-white matter boundary blurring (HGWBB). Given that the layered structure is obscure in HS, there have been no reports on the quantitative evaluation of HGWBB and its relationship with the clinical outcome. Thus, this study aims to correlate the extent of HGWBB to its clinical manifestation of HS. METHODS: Fifty-four patients with temporal lobe epilepsy who underwent hippocampal resection were enrolled. To evaluate HGWBB quantitatively, we defined an index by calculating the standard deviation of the intrahippocampal signal on short tau inversion recovery. In addition, we created a prognostic scoring system using four criteria, including hippocampal signal intensity, size of hippocampal cross-sectional area, presence of temporal lobe lesions, and the HGWBB index. RESULTS: The HGWBB index was significantly lower on the affected side than on the unaffected side (p < 0.001). This trend was more prominent in the poor prognosis group than that in the good prognosis group. The prognostic scoring system revealed that when three or more criteria were positive, the prognostic accuracy reached 87.5% sensitivity and 71.7% specificity. CONCLUSION: The HGWBB index is useful for the diagnosis of temporal lobe epilepsy with HS and for predicting seizure outcomes when used with another index of hippocampal volume loss and increased signal intensity.

Microsurgical techniques in temporal lobe epilepsy.

Temporal lobe resection is the most prevalent epilepsy surgery procedure. However, there is no consensus on the best surgical approach to treat temporal lobe epilepsy. Complication rates are low and efficacy is very high regarding seizures after such procedures. However, there is still ample controversy regarding the best surgical approach to warrant maximum seizure control with minimal functional deficits. We describe the most frequently used microsurgical techniques for removal of both the lateral and mesial temporal lobe structures in the treatment of medically intractable temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (corticoamygdalohippocampectomy and selective amygdalohippocampectomy). The choice of surgical technique appears to remain a surgeon's preference for the near future. Meticulous surgical technique and thorough three-dimensional microsurgical knowledge are essentials for obtaining the best results.

Multinodular and vacuolating neuronal tumor affecting amygdala and hippocampus: A quasi-tumor?

Multinodular and vacuolating neuronal tumors (MVNT) have been referred to as distinctive neuronal tumors whose characteristic features include multiple nodules localized in the subcortical white matter. MVNT are composed of vacuolating dysplastic neurons reactive to HuC/HuD. A significant overexpression of alpha-internexin (INA) limited to the stroma of nodules was reported in one tumor. Since genetic analyses have failed to demonstrate any consistent alterations, the nosological position as well as the nature of MVNT, namely, neoplastic or dysplastic, remains unclear. We herein present another example of MVNT involving the amygdala and anterior hippocampus in a 41-year-old man. In addition to the nodular lesions described earlier, we found INA-positive ribbon-like lesions that replaced neuropil and extended along the hippocampal gray matter. We also identified dysplastic neurons infiltrating into the CA4 hilus of the hippocampus. Intense INA expression was present in the stroma as well as the cytoplasmic membrane of dysplastic neurons and their processes. While the invasiveness suggested a neoplasm, a relatively restrictive, either nodular or ribbon-like growth pattern with INA-positive abnormal neuropil suggested a hamartoma. Such quasi-tumors should be accommodated in the World Health Organization classification of tumors of the central nervous system, as are dysembryoplastic neuroepithelial tumor and Lhermitte-Duclos disease.

Surgery for amygdala enlargement with mesial temporal lobe epilepsy: pathological findings and seizure outcome.

OBJECTIVE: Amygdala enlargement (AE) has been suggested to be a subtype of mesial temporal lobe epilepsy (MTLE). However, most reports related to AE have referred to imaging studies, and there have been few reports regarding surgical and pathological findings. The present study was performed to clarify the surgical outcomes and pathology of AE. METHODS: Eighty patients with drug-resistant MTLE were treated surgically at the Tokyo Metropolitan Neurological Hospital between April 2010 and July 2013. Of these patients, 11 were diagnosed as AE based on presurgical MRI. Nine patients with AE underwent selective amygdalohippocampectomy, while the remaining two patients underwent selective amygdalotomy with hippocampal transection. Intraoperative EEG was routinely performed. The histopathology of the resected amygdala tissue was evaluated and compared with the amygdala tissue of patients with hippocampal sclerosis. RESULTS: Pathological findings indicated that 10 of 11 specimens had closely clustering hypertrophic neurons with vacuolisation of the background matrix. Slight gliosis was seen in nine specimens, while the remaining two showed no gliotic changes. Intraoperative EEG showed abnormal sharp waves that seemed to originate not from the amygdala but from the hippocampus in all cases. Ten patients became seizure-free during the postoperative follow-up period. CONCLUSIONS: Histopathologically, clustering hypertrophic neurons and vacuolation with slight gliosis or without gliosis were considered to be pathological characteristics of AE. Amygdalohippocampectomy or hippocampal transection with amygdalotomy is effective for seizure control in patients with AE.

Efficacy of hippocampal transection for left temporal lobe epilepsy without hippocampal atrophy.

We describe a case of left temporal lobe epilepsy without hippocampal atrophy. A 31-year-old woman presented with typical symptoms of complex partial seizures. Magnetic resonance imaging demonstrated slightly obscure internal structures in the left hippocampus. Scalp electroencephalography revealed interictal epileptiform discharges in the left temporal lobe. A Wada test with propofol determined the language-dominant hemisphere to be the left. Intraoperative electrocorticography revealed active epileptic discharges in the hippocampus and the anterior temporal basal area. The hippocampal epileptic area was treated with multiple transection, which led to the complete cessation of epileptic discharges. After surgery, the Rey Auditory Verbal Learning Test score decreased from 12 to 9. However, it returned to the preoperative level 6months after surgery. We describe this case as a typical example demonstrating the efficacy of hippocampal transection for seizure control and the preservation of verbal memory.

Surgical Technique and Outcome of Extensive Frontal Lobectomy for Treatment of Intracable Non-lesional Frontal Lobe Epilepsy.

Although extensive frontal lobectomy (eFL) is a common surgical procedure for intractable frontal lobe epilepsy (FLE), there have been very few reports regarding surgical techniques for eFL. This article provides step-by-step descriptions of our surgical technique for non-lesional FLE. Sixteen patients undergoing eFL were included in this study. The goals were to maximize gray matter removal, including the orbital gyrus and subcallosal area, and to spare the primary motor and premotor cortexes and anterior perforated substance. The eFL consists of three steps: (1) positioning, craniotomy, and exposure; (2) lateral frontal lobe resection; and (3), resection of the rectus gyrus and orbital gyrus. Resection ahead of bregma allows preservation of motor and premotor area function. To remove the orbital gyrus preserving anterior perforated substance, it is essential to visualize the olfactory trigone beneath the pia. It is important to observe the surface of the contralateral medial frontal lobe for complete removal of the subcallosal area of the frontal lobe. Thirteen patients (81.25%) became seizure-free and three patients (18.75%) continued to have seizures. None of the patients showed any complications. The eFL is a good surgical technique for the treatment of intractable non-lesional FLE. For treatment of epilepsy by eFL, it is important to resect the non-eloquent area of the frontal lobe as much as possible with preservation of the eloquent cortex.

IVIG in childhood primary angiitis of the central nervous system: A case report.

Aggressive immunosuppressive therapies have been proposed to treat primary angiitis of the central nervous system (PACNS). Here, we report the first successfully stabilized case of childhood, small-vessel PACNS with intravenous immunoglobulin (IVIG) therapy. A 12-year-old boy was admitted to our hospital complaining of recurrent headaches and upper-left homonymous quadrantanopia, since the age of 11 years. Brain computed tomography scans revealed fine calcification in the right temporal and occipital lobes. Brain magnetic resonance imaging scans revealed white matter lesions, with gadolinium enhancement, which waxed, waned, and migrated for 1 year, without immunomodulatory therapies. A cerebrospinal fluid study showed pleocytosis (12 cells per µl). No clinical or serological findings suggested systemic inflammation or vasculitis. Brain angiography was unremarkable. Brain biopsy revealed thickened and hyalinized small vessels, with intramural infiltration of inflammatory cells, which confirmed the diagnosis of small-vessel PACNS. Because the patient developed surgical site infection following biopsy, the administration of monthly IVIG (2 g/kg) was prescribed, instead of immunosuppressive agents. After IVIG therapy, the patient remained stable, except for a single episode of mild radiological exacerbation at 16 months, which occurred when the IVIG interval was expanded. Oral prednisone was added and gradually tapered. At 50 months, his intellectual abilities and motor functions were normal, although he showed residual upper-left homonymous quadrantanopia and post-exercise headache. A temporary headache, associated with the immunoglobulin infusion, was resolved by slowing the infusion rate. PACNS should be treated aggressively to improve prognosis. However, when immunosuppressants are contraindicated, IVIG may be an alternative therapeutic option.

Memory outcome following transsylvian selective amygdalohippocampectomy in 62 patients with hippocampal sclerosis.

OBJECT: It remains unclear whether selective amygdalohippocampectomy, an operative technique developed for use in epilepsy surgery to spare unaffected brain tissue and thus minimize the cognitive consequences of temporal lobe surgery, actually leads to a better memory outcome. The present study was performed to determine the effects of selective surgery on memory outcome in patients with intractable mesial temporal lobe epilepsy due to hippocampal sclerosis treated using transsylvian selective amygdalohippocampectomy (TSA). METHODS: The study population consisted of 62 patients with left hemisphere language dominance who underwent left-(31 patients) or right-sided (31 patients) TSA. All patients underwent comprehensive neuropsychological testing before and 1 month and 1 year after unilateral TSA. Verbal Memory I, Nonverbal Memory I, Total Memory, Attention, and Delayed Recall were assessed using the Wechsler Memory Scale-Revised, whereas Verbal Memory II was assessed using the Miyake Verbal Retention Test (MVRT), and Nonverbal Memory II was assessed using the Benton Visual Retention Test. Separate repeated-measures multivariate analysis of variance (MANOVA) were performed for these intervals with memory scores. RESULTS: The results of MANOVA indicated that patients who underwent right-sided TSA showed significant improvements in Verbal Memory I (preoperatively vs 1 month postoperatively, p < 0.0001; and preoperatively vs 1 year postoperatively, p = 0.0002), Nonverbal Memory I (preoperatively vs 1 month postoperatively, p = 0.0003; and preoperatively vs 1 year postoperatively, p = 0.006), and Delayed Recall (preoperatively vs 1 month postoperatively, p = 0.028) at both 1-month and 1-year follow-ups. In addition, Verbal Memory II (MVRT) was also significantly improved 1 year after surgery (p = 0.001). In the group of patients who underwent left-sided TSA, both Verbal Memory I and II were maintained at the same level 1 month after surgery, whereas the Verbal Memory I score 1 year after surgery increased with marginal significance (p = 0.074). In addition, Verbal Memory II showed significant improvement 1 year after surgery (p = 0.049). There were no significant changes in Nonverbal Memory I and II, Attention, or Delayed Recall at either the 1-month or 1-year follow-up. CONCLUSIONS: Results of the present study indicated that left-sided TSA for hippocampal sclerosis tends to improve verbal memory function with the preservation of other types of memory function. Moreover, right-sided TSA for hippocampal sclerosis can lead to significant improvement in memory function, with memory improvement observed 1 month after right-sided TSA and persisting 1 year after surgery.

Prediction of seizure outcome following epilepsy surgery: asymmetry of thalamic glucose metabolism and cerebral neural activity in temporal lobe epilepsy.

OBJECTIVE: The objective of this retrospective study is to analyze whether preoperative functional imaging studies using FDG-PET and MEG enable prediction of postoperative seizure outcomes. METHODS: Thirty-six patients with intractable temporal lobe epilepsy were studied. Asymmetry index of tCMRgluc (PET-AI) and the equivalent current dipole intensity of first response of SEF (SEF-AI) were determined preoperatively using (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and magnetoencephalography (MEG), respectively. Seizure outcomes were evaluated according to the classification proposed by the International League Against Epilepsy (ILAE) at least 24 months after resection of epileptic focuses. Twelve healthy volunteers were included in this study to determine the normal value. RESULTS: Quantitative analysis revealed mean PET-AI in the patients was 5.4+/-5.2% (significantly different from normal controls); mean SEF-AI was 25.2+/-20.6% (not significantly different). PET-AI was positive (indicative of epileptic focus) in 29 of 36 patients (80.6%), while SEF-AI was positive in 17 of 36 patients (47.2%). Although no significant correlation between PET-AI and SEF-AI was noted (r=0.43), concordant asymmetry in both PET-AI and SEF-AI was significantly associated with better seizure outcome than discordant or paradoxical asymmetry of both factors (p<0.01). CONCLUSIONS: The results suggest that quantitative analysis of tCMRgluc with SEF may be helpful in characterizing the preoperative epileptogenic condition and predicting postoperative seizure outcome in patients with temporal lobe epilepsy, although a constellation of developmental brain abnormalities and environmental factors that together produce epilepsy need to be further explored.

Hippocampal Transection Plus Tumor Resection as a Novel Surgical Treatment for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations.

OBJECTIVE: The optimal surgical treatment for cavernous malformation-related temporal lobe epilepsy (CRTLE) is still controversial because it frequently involves the hippocampus as an epileptogenic zone. Here we describe our unique surgical strategy of performing hippocampal transection (HT) plus tumor resection for CRTLE to solve the question of how to balance postoperative seizure outcomes and neuropsychologic outcomes. METHODS: From 2005 to 2016, 7 cases of HT (3 on dominant side) plus tumor resection were performed for patients with CRTLE. We routinely perform intraoperative electrocorticography just before and after the resection of the tumor with hemosiderin rim. In cases with residual spikes from the hippocampus after the resection, we add HT, considering laterality of the lesion, preoperative memory functions, and magnetic resonance imaging abnormalities in hippocampi. Patient information, including seizure outcomes and preoperative and postoperative (24 months) Wechsler Memory Scale-Revised (WMS-R), were collected. RESULTS: In the mean follow-up of 62.7 months (range 20-119), the postoperative seizure outcome was as follows: Engel class I in 6 cases (85.7%) and II in 1 case (14.3%). Perioperative changes in WMS-R score were as follows: 93.5 preoperatively versus 99.5 postoperatively (P = 0.408) in verbal memory and 90.7 versus 98.0 (P = 0.351) in delayed recall. Overall, no patient presented with more than 25% decline in any of the WMS-R indices postoperatively. CONCLUSIONS: Despite the small sample size and noncontrolled study design, postoperative seizure outcomes were deemed acceptable with favorable memory outcomes, which rather improved postoperatively with marginal statistical significance. In patients with CRTLE, additional HT is a reasonable treatment option.

The effect of dexmedetomidine on electrocorticography in patients with temporal lobe epilepsy under sevoflurane anesthesia.

BACKGROUND: Although dexmedetomidine is often used in neuroanesthesia and neuronal critical care practice, its effect on cerebral electrical activity in those with an abnormal electroencephalogram is not known. The electrocorticogram (ECoG), a sensitive method for examining the effect of drugs on cerebral electrical activity and surgical treatment for epilepsy, is usually guided by monitoring of the ECoG. We investigated the effect of dexmedetomidine on ECoG in patients with epilepsy undergoing surgery with sevoflurane. METHODS: Patients with medically intractable temporal lobe epilepsy undergoing resection of the epileptic foci (n = 11) were enrolled. Under general anesthesia with 2.5% sevoflurane and end-tidal carbon dioxide tension at 30 mm Hg, ECoG was recorded by strip electrodes with eight contacts placed on the mesial temporal lobe ipsilateral to the epilepsy foci. Dexmedetomidine was given as a computer-controlled infusion to achieve target plasma concentrations of 0.5 and 1.5 ng/mL. Each concentration was maintained for 20 min and ECoG was recorded before infusion of dexmedetomidine and between the 10th and 20th min after starting infusion. The median frequency of ECoG, spectral power density of each spectral band, and number of spikes at each concentration of dexmedetomidine were compared by Kruskal-Wallis test, followed by Student-Newman-Keuls test. RESULTS: The median frequency of ECoG in 88 leads from all leads from all patients was significantly decreased by 1.5 ng/mL of dexmedetomidine compared with those at baseline and 0.5 ng/mL (P = 0.003 and 0.03, respectively); however, spectral power densities in the frequency bands: delta (<4 Hz), theta (> or =4 and <8 Hz), alpha (> or =8 and <13 Hz), and beta (> or =13 Hz), were not changed. Neither the number of leads with spikes nor the number of spikes in all leads and in the lead with highest number of spikes at baseline was affected by dexmedetomidine. CONCLUSIONS: Dexmedetomidine at plasma concentrations of 0.48 and 1.60 ng/mL decreased the median frequency of ECoG, but did not affect spike activity in patients with temporal lobe epilepsy anesthetized with 2.5% sevoflurane.

Transventricular hemispherotomy for surgical treatment of intractable epilepsy.

Surgical procedures for cerebral hemispherotomy may be broadly divided into those using a lateral and those using a vertical approach. However, careful study of surgical procedures using the lateral approach described in the literature shows differences in the approach to the ventricles. We discuss the application of transventricular hemispherotomy as a technique which provides relatively easy ventricular access for cerebral hemispherotomy. Transventricular hemispherotomy was successfully performed in a 36-year-old woman who was diagnosed with intractable epilepsy due to Sturge-Weber disease, and in a 25-year-old man who had developed intractable post-traumatic seizures after suffering cerebral contusion in a traffic accident as a child. These patients had no seizures or complications after surgery, and both patients have been weaned from antiepileptic drugs. The transventricular approach, as compared with other lateral approaches described in the literature, provides easy access to the ventricular cavity. Transventricular hemispherotomy proved to be a useful approach that allowed the following four common steps in cerebral hemispherotomy to be performed safely: (i) interruption of the internal capsule and corona radiata; (ii) resection of the medial temporal structures; (iii) transventricular corpus callosotomy; and (iv) disruption of the frontal horizontal fibers.

Falcotentorial meningioma: surgical outcome in 14 patients.

OBJECT: The authors evaluated their surgical experience over 20 years with 14 treated falcotentorial meningiomas. METHODS: In the past 20 years, 14 patients with falcotentorial junction meningiomas were surgically treated. There were seven men and seven women, whose ages ranged from 34 to 79 years. On the basis of neuroimaging studies, the authors analyzed the influence of the anatomical relationship of the tumor to the vein of Galen, patency of the vein of Galen, tumor size, and the signal intensities on the magnetic resonance images to determine possible difficulties that might be encountered during surgery and to prognosticate the outcome of surgery. Depending on the relationship with the vein of Galen, tumors were labeled as either a superior or an inferior type. All tumors were resected via an occipital transtentorial approach. The surgical outcome in eight patients was excellent; in the remaining six patients, it was fair. Of the prognostic factors, tumor location especially seemed to be the most important (p < 0.01, Fisher exact test). The outcome associated with the inferior type of tumor was significantly less optimal probably due to the relationship to the deep veins and the brainstem. In this series, the occlusion of deep veins did not significantly influence outcome. CONCLUSIONS: . Classification of the tumor location by preoperative neuroimaging studies can be helpful in estimating the surgical difficulty that might be encountered in treating the falcotentorial junction meningioma.

Effectiveness of cerebral hemispherotomy for improving behavioral disorders associated with intractable post-traumatic seizures.

A 25-year-old man presented with intractable post-traumatic seizures after suffering cerebral contusion in a traffic accident at age 5 years. Cerebral hemispherotomy was performed to transect the neuronal fibers to interrupt connections between seizure foci in wide areas of the brain, and to minimize the resected brain parenchyma. His seizures resolved and behavioral disorders improved, which had been impaired since age 8 years. Increased glucose metabolism in the normal frontal lobe detected by interictal fluorodeoxyglucose-positron emission tomography was correlated with the improvements in behavioral disorders. These findings suggest that the effects of seizures may be reversible in brain areas connected with, but remote from, the epileptogenic cortex.

Posterior callosotomy using a parietooccipital interhemispheric approach in the semi-prone park-bench position.

A 2-stage corpus callosotomy is accepted as a palliative procedure for patients older than 16 years with, in particular, medically intractable generalized epilepsy and drop attack seizures and is preferable for a lower risk of disconnection syndrome. Although the methods by which a previously performed craniotomy can be reopened for posterior callosotomy have already been reported, posterior corpus callosotomy using a parietooccipital interhemispheric approach with the patient in a semi-prone park-bench position has not been described in the literature. Here, the authors present a surgical technique for posterior callosotomy using a parietooccipital interhemispheric approach with a semi-prone park-bench position as a second surgery. Although this procedure requires an additional skin incision in the parietooccipital region, it makes the 2-stage callosotomy safer and easier to perform because of reduced intracranial adhesion, less bleeding, and an easier approach to the splenium of the corpus callosum.

Abnormal discharges from the temporal neocortex after selective amygdalohippocampectomy and seizure outcomes.

The present study examined the relationship between residual discharges from the temporal neocortex postoperatively and seizure outcomes, in mesial temporal lobe epilepsy (MTLE) patients with hippocampal sclerosis (HS) who were treated with selective amygdalohippocampectomy (SelAH). Abnormal discharges from the temporal neocortex are often observed and remain postoperatively. However, no recommendations have been made regarding whether additional procedures to eliminate these discharges should be performed for seizure relief. We retrospectively analyzed 28 patients with unilateral MTLE and HS, who underwent transsylvian SelAH. The mean follow-up period was 29 months (range: 16-49). In the pre- and postresection states, electrocorticography (ECoG) was recorded for the temporal base and lateral temporal cortex. The extent of resection was not influenced by the results of the preresection ECoG. Even if residual abnormal discharges were identified on the temporal neocortex, no additional procedures were undertaken to eliminate these abnormalities. The postresection spike counts were examined to determine the postresective alterations in spike count, and the frequency of residual spike count. The seizure outcomes were evaluated in all patients using the Engel classification. The postoperative seizure-free rate was 92.9%. No significant correlations were seen between a decreasing spike count and seizure outcomes (p=0.9259), or between the absence of residual spikes and seizure outcomes (p=1.000). Residual spikes at the temporal neocortex do not appear to influence seizure outcomes. Only mesial temporal structures should be removed, and additional procedures to eliminate residual spikes are not required.

Anatomical analysis of different hemispherotomy procedures based on dissection of cadaveric brains.

OBJECT: Functional hemispherectomy, itself a modification of anatomical hemispherectomy, has been further modified to a less invasive method (hemispherotomy), in which cortical resection is minimized and the rest of the affected hemisphere is functionally isolated by transecting its projection and commissural fibers. Although descriptions of three different types of hemispherotomy procedures have been published, the authors believe that it is important to develop a common and universally acceptable method based on a systematic analysis of topographic anatomy and neuronal connections. To this end, they have analyzed the three aforementioned procedures on the basis of meticulous fiber dissections in previously frozen formalin-fixed human brains. METHODS: The brain anatomy pertinent to surgical hemispherotomy is described in conjunction with dissection studies in 14 previously frozen, formalin-fixed human brains. The anatomical landmarks necessary for performing particular neuronal fiber resections are identified, and their relationships with operative methods are discussed, with an emphasis on commonalities among the three hemispherotomy procedures. CONCLUSIONS: In this analysis the authors confirmed that hemispherotomy typically consists of four common procedures: 1) interruption of the internal capsule and corona radiata; 2) resection of the medial temporal structures; 3) transventricular corpus callosotomy; and 4) disruption of the frontal horizontal fibers. After meticulous dissection of cadavers, the authors have designated a reliable method for performing these four operations that may be applicable as a commonly used procedure.

Prevention of postoperative posterior tethering of spinal cord after resection of ependymoma.

OBJECT: The authors evaluated an alternative method to avoid postoperative posterior tethering of the spinal cord following resection of spinal ependymomas. METHODS: Twenty-five patients with spinal ependymoma underwent surgery between 1978 and 2002. There were 16 male and nine female patients whose ages at the time of surgery ranged from 14 to 64 years (mean 41.8 years). The follow-up period ranged from 6 to 279 months (mean 112.4 months). In the initial 17 patients (Group A), the procedure to prevent arachnoidal adhesion consisted of the layer-to-layer closure of three meninges and laminoplasty. In the subsequently treated eight patients (Group B), the authors performed an alternative technique that included pial suturing, dural closure with Gore-Tex membrane-assisted patch grafting, and expansive laminoplasty. In Group A, postoperative adhesion was radiologically detected in eight cases (47%), and delayed neurological deterioration secondary to posterior tethering of the cord was found in five cases. In Group B, there was no evidence of adhesive posterior tethering or delayed neurological deterioration. A significant intergroup statistical difference was demonstrated for radiologically documented posterior tethering (p < 0.05, Fisher exact test). Moreover, patients with radiologically demonstrated posterior tethering suffered a significant delayed neurological functional deterioration (p < 0.01, Fisher exact test). CONCLUSIONS: This new technique for closure of the surgical wound is effective in preventing of postoperative posterior spinal cord tethering after excision of spinal ependymoma.

Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty.

OBJECTIVE: The authors describe a new surgical technique for cervical laminoplasty that was performed in 25 patients. The posterior elements along with the various ligaments are removed en bloc and are stabilized in a lift-up position by placing hydroxyapatite (HA) laminar spacers and titanium miniplates and screws. The procedure and clinical results are discussed. METHODS: The posterior spinal elements, including the lamina(e), spinous process(es), and various attached ligaments, are removed en bloc by incising the lamina in its lateral aspect. Trapezoid-shaped HA spacers are placed between the cut ends of the laminae or between the laminae and lateral masses bilaterally at each level. Malleable titanium miniplates and screws are used for fixation of the spacers. The fixation of transected laminae was judged to be successful. Postoperative care included application of a soft neck collar for 1 week but no further restriction of activity. Surgery-related outcome was assessed in the 21 patients who attended more than 6 months of follow up after laminoplasty. There were 18 men and three women who ranged in age from 27 to 81 years. Cervical stenotic myelopathy was demonstrated in 15 patients who underwent decompressive and expansive laminoplasty, and spinal tumors were documented in six patients who underwent a nonexpansive laminoplasty. Postoperative and follow-up computerized tomography scans demonstrated no hardware failure. Bone formation around the spacers was observed either at 6- or at 9-month follow-up examination in all 21 patients. Fusion of the reconstructed laminae was found to be completed at 12 months in all 18 patients able to attend follow up for this duration. Spinal alignment and the range of motion of the cervical spine were well preserved. In patients with stenotic cervical myelopathy, neurological and anatomical outcome of canal expansion were satisfactory. CONCLUSIONS: This technique enables rigid laminoplasty while maintaining anatomical and biomechanical integrity of posterior elements of cervical spine. Expansive and nonexpansive laminoplasty procedures are possible.