Resection of lateral temporal lobe arteriovenous malformations

Background

Cerebral arteriovenous malformations (AVMs) can be formidable lesions to treat. There are four modalities available for treatment: expectant management, radiosurgery, embolization, and microsurgery. In order to make a decision about treatment, the surgeon must consider the natural history of the lesion versus the rate of treated morbidity and mortality. Characteristics of temporal lobe AVMs such as their location, the potential for deep-seated arterial feeders and deep venous drainage, increase the risk of early clinical onset, hemorrhage, and overall morbidity and mortality (Fleetwood and Steinberg; Lancet 359:863-873, 3) and provide an additional challenge to surgeons attempting to remove the lesion while preserving eloquent local structures.

Methods

In this paper, we demonstrate our technique for the microsurgical resection of lateral temporal lobe AVMs. In order to maximize access to the lesion for safe resection, a large craniotomy is utilized, with the malformation separated from the MCA feeding arteries and underlying cortex, with care taken not to compromise en passage vessels. The entire nidus is resected and intraoperative angiography confirms appropriate resection.

Conclusions

Microsurgical resection remains an important part of the treatment paradigm for temporal lobe AVMs. In appropriately selected patients, this can be done with minimal morbidity.     

White matter fiber dissection of the optic radiations of the temporal lobe and implications for surgical approaches to the temporal horn

OBJECT: The aim of this anatomical study was to define more fully the three-dimensional (3D) relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe by using the Klingler white matter fiber dissection technique. These findings were correlated with established surgical trajectories to the temporal horn. Such surgical trajectories have implications for amygdalohippocampectomy and other procedures that involve entering the temporal horn for the resection of tumors or vascular lesions. METHODS: Ten human cadaveric hemispheres were prepared with several cycles of freezing and thawing by using a modification of the method described by Klingler. Wooden spatulas were used to strip away the deeper layers of white matter progressively in a lateromedial direction, and various association, projection, and commissural fibers were demonstrated. As the dissection progressed, photographs of each progressive layer were obtained. Special attention was given to the optic radiation and to the sagittal stratum of which the optic radiation is a part. The trajectories of fibers in the optic radiation were specifically studied in relation to the lateral, medial, superior, and inferior walls of the temporal horn as well as to the superficial anatomy of the temporal lobe. In three of the hemispheres coronal sections were made so that the relationship between the optic radiation and the temporal horn could be studied more fully. In all 10 hemispheres that were dissected the following observations were made. 1) The optic radiation covered the entire lateral aspect of the temporal horn as it extends to the occipital horn. 2) The anterior tip of the temporal horn was covered by the anterior optic radiation along its lateral half. 3) The entire medial wall of the temporal horn was free from optic radiation fibers, except at the level at which these fibers arise from the lateral geniculate body to ascend over the roof of the temporal horn. 4) The superior wall of the temporal horn was covered by optic radiation fibers. 5) The entire inferior wall of the temporal horn was free from optic radiation fibers anterior to the level of the lateral geniculate body. CONCLUSIONS: Fiber dissections of the temporal lobe and horn demonstrated the complex 3D relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe. Based on the results of this study, the authors define two anatomical surgical trajectories to the temporal horn that would avoid the optic radiations. The first of these involves a transsylvian anterior medial approach and the second a pure inferior trajectory through a fusiform gyrus. Lateral approaches to the temporal horn through the superior and middle gyri, based on the authors' findings, would traverse the optic radiations.     

Neurosurgical topography of the optic radiation in the temporal lobe

Summary Damage to the optic radiation during surgery in the temporal lobe results in more or less severe visual field defects. In the present study, the optic radiation was represented by either Klingler's fibre dissection technique or by consecutive frontal sections respectively in 25 formalin-fixed human hemispheres. This enabled one to gain exact data on the three-dimensional course, the length and other measurements of this important fibre system. In addition, its relations to the temporal horn, the trigonum and the occipital horn of the lateral ventricle were determined. The results of these measurements are discussed with respect to various surgical interventions involving the temporal lobe.     

Microdialysis of the lateral and medial temporal lobe during temporal lobe epilepsy surgery

BACKGROUND: This study was undertaken to establish whether, in temporal lobe epilepsy (TLE), there are relative differences between the lateral and ipsilateral medial temporal lobe in the extracellular levels of 3 of the human brain's major neuroactive amino acids. METHODS: Seven generally anesthetized patients with TLE undergoing anatomically standardized resective surgery had at operation microdialysis catheters inserted within the middle temporal gyrus (ie, lateral temporal lobe) and anterior hippocampus (ie, medial temporal lobe). Surface electrocorticography (ECoG) recordings were also obtained. Samples of 10-minute dialysate were quantified for glutamate, aspartate, and gamma-aminobutyric acid (GABA) using high-performance liquid chromatography; corresponding ECoG data were assessed for epileptiform activity. Where available, resection tissue was subjected to histopathological analysis. RESULTS: The ratio of mean "sample 3" dialysate levels of glutamate, aspartate, and GABA was approximately 20:2:1, respectively, in both the minimally epileptiform lateral (n = 7) and medial (n = 5) temporal lobe; between the 2 sets of samples, these levels were not significantly different (P > 0.05 for each amino acid studied). From the vigorously epileptiform medial temporal lobe of 2 patients, sample 3 dialysate levels of the excitatory amino acids glutamate and aspartate were found in considerably greater concentrations (between 15- and 37-fold) with correspondingly less dramatic increases of the inhibitory amino acid GABA (more than 11- and 13-fold). Laterally resected tissue (obtained in 3 cases) did not demonstrate significant cortical or subcortical abnormalities; medial resection tissue from all patients demonstrated, in varying degrees, hippocampal sclerosis. CONCLUSIONS: In the absence of significant tissue hyperexcitability, despite known differences in local cellular and/or histopathological architecture, the extracellular relationship among glutamate, aspartate, and GABA is not dissimilar in both the lateral and ipsilateral medial temporal lobe of TLE patients. Considerable disparity in dialysate levels recovered (eg, from the vigorously epileptiform medial temporal lobe) may be related to the functional (ie, hyperexcitable) status of the sampled tissue.     

Modifications of temporal lobectomy according to the extent of epileptic foci and speech-related areas

The authors applied combined depth and subdural electrodes in patients with intractable complex partial seizures to detect the precise extent of epileptic foci and functionally map speech-related areas. The medial temporal structures were explored with depth electrodes and the lateral temporal cortex with subdural electrodes. On the speech-dominant side, electrical stimulation was given to demarcate the speech-related areas in the lateral temporal cortex. Based on these data, the extent of surgical resections was tailored to include as much of the epileptogenic areas as possible while preserving the functionally essential zones of the lateral cortex. According to the range of resection, three different approaches were employed for en bloc ablation of the lateral cortex and opening of the inferior ventricle. The results thus acquired have been satisfactory in terms of seizure control and the preservation of speech function.     

Use of an anteromedial subdural strip electrode in the evaluation of medial temporal lobe epilepsy. Technical note

The temporal lobe is the most common site of partial epilepsy that is amenable to surgical therapy, and therefore ictal localization in this region is important. The authors describe the application of an anteromedial subdural strip electrode for the evaluation of epilepsy originating from the medial temporal lobe. This strip is advanced around the temporal pole and underneath the lesser wing of the sphenoid bone as it follows the medial temporal lobe contour. The advantages of this method of placement are the consistent path and reliable final position of the strip along the medial basal temporal lobe surface. This method allows adequate coverage of the parahippocampal gyrus along its long axis extending posterior to the level of the collicular plate. This technique has been used with no complications during intracranial monitoring of more than 100 patients with presumed temporal lobe epilepsy.     

"Tangential" resection of medial temporal lobe arteriovenous malformations with the orbitozygomatic approach

OBJECTIVE: Arteriovenous malformations (AVMs) of the medial temporal lobe are usually resected through subtemporal-transcortical approaches that provide a trajectory that is perpendicular to the plane of the AVM. The pterional approach is sometimes used for AVMs in the uncus and amygdala, but it is not recommended for AVMs in the hippocampal region because it provides a "tangential" approach with limited access to posterior feeding arteries and draining veins. The orbitozygomatic approach enhances exposure along this tangential trajectory and was used in a consecutive series of 10 patients to determine its advantages. METHODS: During a 5.7-year period, 43 patients underwent resection of temporal lobe AVMs, 10 of which were located in the medial temporal lobe (amygdala and uncus [Region A] or hippocampus, parahippocampus, and fusiform gyrus [Region B]). AVMs were evenly distributed by region and by hemispheric dominance and included two Spetzler-Martin Grade IV lesions. An orbitozygomatic approach was used in all cases. RESULTS: Complete resection was accomplished in nine patients, and one patient underwent multimodality management with postoperative stereotactic radiosurgery. Good outcomes (Rankin outcome score 相似文献   

A combined subtemporal and transventricular/transchoroidal fissure approach to medial temporal lesions

OBJECTIVE: To minimize therapeutic morbidity such as cognitive function disturbance and vascular injury to perforating arteries, preoperative functional mapping of the basal temporal lobe functions was performed and the medial temporal lesions were resected via a combined subtemporal and transventricular/transchoroidal fissure approach. METHODS: Twenty-one patients with medial temporal lesions including tumors, arteriovenous malformations, and medial temporal lobe epilepsy underwent operation. The neurovascular structures in the ambient cistern were first dissected free from the medial temporal lobe with a conventional subtemporal approach. Then, the temporal horn was opened through the basal surface of the temporal lobe. Finally, the ambient cistern was accessed from the temporal horn through the choroidal fissure. In five patients whose lesions were revealed to be located on the dominant side by preoperative intracarotid amytal administration test (Wada test), functional mapping of the basal temporal lobe language cortex was monitored for 1 week by use of a subdural electrocorticogram grid before the extirpation surgery. The entrance point from the temporal base to the temporal horn was determined by the result of the functional mapping. RESULTS: The lesions were resected safely and completely in all cases. Language and cognitive functions were preserved even in patients with the basal language area on the dominant side. CONCLUSION: Surgeons can confirm the important neurovascular structures from the subtemporal route and from the transtemporal horn route by a combined subtemporal and transventricular/transchoroidal fissure approach. This approach is especially effective for avoiding ischemic complications by allowing direct confirmation of the anterior choroidal and thalamoperforating arteries.     

Language function following anterior temporal lobectomy

The authors report the results of a prospective investigation that evaluated postoperative changes in language function after dominant (29 cases) or nondominant (35 cases) anterior temporal lobectomy for treatment of complex partial seizures. These patients received conservative resection of lateral temporal cortex but aggressive resection of medial temporal cortex. None of the patients underwent functional mapping of cortical language ability. All patients were assessed with a standardized aphasia battery (Multilingual Aphasia Examination) before and 6 months after surgery. Postoperatively, the dominant anterior temporal lobectomy group did not show any significant losses in language function compared to patients who underwent nondominant anterior temporal lobectomy. In addition, the dominant temporal lobectomy group showed significant postoperative improvement in complex receptive language comprehension compared to the nondominant group. These results suggest that patients with complex partial seizures of medial temporal lobe onset can undergo a conservative resection of lateral temporal cortex without language mapping. Such surgery carries little risk to language function and provides an excellent postoperative surgical outcome.     

Using the zygomatic root as a reference point in temporal lobe surgery

Background

The zygomatic root (ZR) is an anatomic landmark routinely identified during cranial procedures. Traditionally, it has been used for identification of structures other than temporal lobe anatomy. The aim of this study was to define the structural relationship between the ZR and temporal lobe anatomy and provide a consistent landmark to guide surgical dissection. To our knowledge, there have been no studies demonstrating this relationship.

Methods

Eighteen DICOM series were analyzed. 2 mm axial MRI slices were reconstructed with the x-axis centered along the zygoma. The posterior point of the ZR that marks the beginning of the groove between the zygoma and temporal bone was identified on all images. Several measures were taken to quantify the relationship of the zygomatic root to surgical landmarks used during temporal lobe surgery.

Results

The inferior temporal gyrus was always found just medial to the ZR. The mean distance between the ZR and temporal pole was 2.75 cm on the right and 2.78 cm on the left. The tip of the temporal horn was located on average 2.4 cm (left) and 2.31 cm (right) medial to the ZR. The tip of the temporal horn was found to be an average distance of 1 mm (left and right) posterior and 1.34 cm (left and right) superior to the ZR. All distances were measured orthogonally for each of the x, y, and z axes.

Conclusion

The zygomatic root is an easily identifiable and consistent bony landmark that can serve as an adjuvant to neuronavigation for identification of temporal lobe surgical anatomy.     

Modified extended pancreatoduodenectomy: en bloc resection of the peripancreatic retroperitoneal tissue and the head of pancreas

Malignant periampullary tumours often invade into retroperitoneal peripancreatic tissues and a positive resection margin following pancreatoduodenectomy is associated with a poor survival. For complete extirpation of the tumour, en bloc resection of the pancreatic head with all retroperitoneal peripancreatic tissue is essential to achieve negative resection margin. A modified radical pancreatoduodenectomy technique that aims to resect all peripancreatic retroperitoneal tissue en bloc with the head of the pancreas is described. We have used this new technique in the last 30 consecutive cases of pancreatoduodenectomy with excellent results as presented in this paper. This technique allows complete en bloc resection of retroperitoneal peripancreatic tissues while preserving normal functional tissue. This technique's advantage is that the resection can be carried out without breaching the retroperitoneal tumour extension plane, thereby minimizing tumour cell spillage.     

Temporal lobe epilepsy: a clinicopathological study with special reference to temporal neocortical changes

The number of patients undergoing surgical treatment for pharmacoresistant temporal lobe epilepsy is rapidly increasing. While there have been many clinicopathological studies concerning the medial structures of the temporal lobe in temporal lobe epilepsy, its lateral structures have received little attention. To examine the nature and frequency of lateral temporal lobe abnormalities that occur in temporal lobe epilepsy, 22 patients who underwent standard anterior temporal lobectomy with hippocampectomy for intractable temporal lobe epilepsy were studied. The mean ages at the onset of seizure and at surgery were 15.9 years and 27.7 years, respectively. The electroclinically determined epileptogenic zones were the medial structures of the temporal lobe in 16 patients and the lateral in six. There was histologic evidence of hippocampal sclerosis in 12 of the 16 patients with medial onset seizures and in three of the six patients with lateral onset seizures. The lateral structures of the temporal lobe showed variable degrees of histological abnormalities in 21 patients. Among these abnormalities, heterotopic white matter neurons were observed in six of the 16 medial patients and in all the lateral patients. Glial changes were also common abnormalities, and often glial fibrillary acidic protein (GFAP)-positive astrocytes were present over the entire temporal lobe. In addition to hippocampal sclerosis, cerebral microdysgenesis and gliosis in the lateral structures of the temporal lobe may have a significant role in epileptogenesis of temporal lobe epilepsy.     

Positive and negative network correlations in temporal lobe epilepsy

Temporal lobe seizures are accompanied by complex behavioral phenomena including loss of consciousness, dystonic movements and neuroendocrine changes. These phenomena may arise from extended neural networks beyond the temporal lobe. To investigate this, we imaged cerebral blood flow (CBF) changes during human temporal lobe seizures with single photon emission computed tomography (SPECT) while performing continuous video/EEG monitoring. We found that temporal lobe seizures associated with loss of consciousness produced CBF increases in the temporal lobe, followed by increases in bilateral midline subcortical structures. These changes were accompanied by marked bilateral CBF decreases in the frontal and parietal association cortex. In contrast, temporal lobe seizures in which consciousness was spared were not accompanied by these widespread CBF changes. The CBF decreases in frontal and parietal association cortex were strongly correlated with increases in midline structures such as the mediodorsal thalamus. These results suggest that impaired consciousness in temporal lobe seizures may result from focal abnormal activity in temporal and subcortical networks linked to widespread impaired function of the association cortex.     

Surgical treatment for intractable epilepsy caused by cavernous angioma in the temporal lobe of the dominant hemisphere--three case reports

The surgical treatment modality for intractable epilepsy with cavernous angioma in the dominant hemisphere is still unclear. Three patients with medically intractable seizures associated with cavernous angioma in the dominant hemispheric temporal lobe underwent tailored resection based on magnetic resonance (MR) imaging, single photon emission computed tomography (SPECT), electroencephalography monitoring (from scalp and sphenoidal electrodes), and neuropsychologic assessment. Epileptogenic zones were located in the area surrounding the angioma in all patients and mesial temporal dysfunction in two patients. The adjacent cortex and gliotic tissues containing hemosiderin were resected, in conjunction with either total or partial resection of the nidus. Intraoperative electrocorticography (ECoG) was then performed. Additional resection of the mesial temporal structures or multiple subpial transection was performed as indicated by the ECoG findings. All three patients have been seizure free and showed no language or cognitive deterioration for 30, 18, and 14 postoperative months, respectively, while receiving tapered antiepileptic medication. Tailored resection based on electrophysiological data, MR imaging, SPECT, and intraoperative ECoG is effective for the treatment of medically intractable seizure associated with cavernous angioma in the temporal lobe of the dominant hemisphere.     

Total temporal bone resection for squamous cell carcinoma

Because of unsatisfactory results in treatment of malignant conditions of the temporal bone, a technique for total en bloc resection of the temporal bone and carotid artery was reported by Graham et al. in 1984. The procedure involves resection of the internal carotid artery, cranial nerves VI through XII, and structures adjacent to the temporal bone. Experience with two additional cases led to numerous modifications in the recommended procedure, as reported by Sataloff and Myers. Additional clinical experience with this technique and its complications has resulted in further modification. Additional pitfalls and specific changes in technique from previous reports are discussed in detail, including a new procedure to assure the adequacy of contralateral venous outflow.     

Extent of mesiobasal resection determines outcome after temporal lobectomy for intractable complex partial seizures.

The extent of resection was assessed in 94 patients who underwent temporal lobectomy for medically intractable complex partial seizures originating from a unilateral seizure focus in the anteromesial temporal lobe. Postoperative magnetic resonance imaging in the coronal plane was used to quantify the extent of resection of lateral and mesiobasal structures according to a 20-compartment model of the temporal lobe. Successful seizure outcome (greater than or equal to 90% reduction in seizure frequency) was accomplished in 83% of the patients (all followed up for more than 1 year; mean duration of follow-up, 25.2 months) and correlated significantly (P less than 0.05) with the extent of mesiobasal resection, regardless of the extent of resection of lateral structures. Successful seizure outcome was accomplished in 81% of the patients with no structural lesions, and also correlated significantly (P less than 0.05) with the extent of mesiobasal resection regardless of the extent of lateral resection. A successful seizure outcome was accomplished in 90% of the 21 patients with structural lesions documented by neuroimaging studies. Two patients who underwent extensive lobectomy without resection of the structural lesion had no reduction in seizure frequency postoperatively. We conclude that the most important factor in determining the outcome of temporal lobectomy in patients with unilateral anteromesial temporal lobe epileptogenicity is the extent of resection of structures in the mesiobasal temporal lobe. In patients with structural lesions, lesion resection may be an added contributor to successful seizure outcome.     

Correction of Thoracic Aortic Aneurysm-Bronchial Fistula

The descending thoracic aorta is the most common site for thoracic aneurysms to occur and may present asymptomatically or manifest itself with an array of symptoms depending on the involvement of adjacent structures. Hemoptysis may occur due to erosion of the aneurysm into a bronchus or the pulmonary parenchyma. This report describes the technique in a patient with a descending thoracic aneurysm who underwent emergent resection of the aneurysm with en bloc removal of the involved left lower lobe of the lung.     

Long-term outcome following radical temporal bone resection for lateral skull base malignancies: a neurosurgical perspective

OBJECT: Primary temporal bone malignancy is a rare form of tumor for which the therapeutic strategy remains controversial. In this study, the authors reviewed their experience with radical temporal bone resection (TBR) of such lesions and analyzed the long-term results to provide treatment recommendations. METHODS: Between 1994 and 2006, 17 patients (10 men and 7 women) underwent total or subtotal TBR for primary temporal bone malignancies. Tumors were graded according to the University of Pittsburgh system. The effects of surgical margins and tumor extensions on patient survival were analyzed using the Kaplan-Meier method. RESULTS: All tumors, except 1, were graded T4 (most advanced). Subtotal TBR was performed in 14 patients, and total TBR was performed in 3. The surgical margin was tumor negative in 10 patients and tumor positive in 7. For large tumors extending into the infratemporal fossa or encroaching on the jugular foramen, orbitozygomatic (3 patients) and posterior transjugular (4 patients) approaches were combined with the standard approach, and en bloc resection with a negative margin was achieved in all cases but 1. The follow-up time ranged from 0.3-11.6 years (mean 3.3 years). The 5-year recurrence-free and disease-specific survival rates were 67.5 and 60.1%, respectively. When a negative surgical margin was achieved, the survival rates improved to 100 and 89%, respectively. CONCLUSIONS: The neurosurgical skull base technique could improve the probability of en bloc resection with a tumor-free margin for extensive temporal bone malignancies, which would cure a subset of patients. The active participation of neurosurgeons would improve patient care in this field.     

A cholangiocellular carcinoma radically resected by central hepatic bisegmentectomy with en bloc resection of the caudate lobe and extrahepatic bile duct

A case of cholangiocellular carcinoma, involving the hepatic hilus, radically resected by central hepatic bisegmentectomy with en bloc resection of the caudate lobe and extrahepatic bile duct is presented. Preoperative surgical planning was carried out on the basis of an evaluation of the findings of ultrasonography, computed tomography, angiography, percutaneous transhepatic portography, and tube cholangiography. The operation lasted for 16 h and 15 min, with 5700 g blood loss. Postoperative recovery was very good and the patient has now been well for 26 months after surgery. Although the surgical technique of central hepatic bisegmentectomy with en bloc resection of the caudate lobe and extrahepatic bile duct is very difficult, this procedure should be indicated for selected cases of cholangiocellular carcinoma involving the hepatic hilus.