Microsurgical and Endovascular Treatments for Ruptured Paraclinoid Aneurysms.

BACKGROUND: The treatment of paraclinoid aneurysms can be challenging due to their relationship to the cavernous sinus, carotid siphon, and optic nerve. The goal of this retrospective analysis is to compare the efficacy and safety of microsurgical versus endovascular treatments for ruptured paraclinoid aneurysms. METHODS: Medical records were reviewed to collect information about patient demographics, risk factors, diagnosis (the position and size of aneurysms), Hunt and Hess grade, and surgical method and outcomes, including modified Rankin Scale (mRS) at the time of discharge and 6 months later, complications, and death. RESULTS: In total, 15 and 6 patients were recruited into the microsurgery and endovascular groups, respectively. No difference was detected regarding age, sex, risk factors, and Hunt and Hess grade. Most patients had ophthalmic segment aneurysms (87% versus 83%; p = 1.000) and small aneurysms (< 10 mm, 67% versus 100%; p = 0.102). In the microsurgical group, five patients (33%) had large aneurysms (10-25 mm); three patients (20%) had multiple aneurysms (all p > 0.05 compared with the endovascular group). The occlusion rate at 6 months was 93% in the microsurgical group and 100% in the endovascular group (p > 0.05). No difference was found regarding mRS or the complication and mortality rates between the two groups (all p > 0.05). The occurrence of complications was not related to the location and size of aneurysms (all p > 0.05). CONCLUSIONS: Our retrospective analysis indicates that good clinical outcomes can be achieved with both microsurgical and endovascular approaches. But further prospective randomized multicenter studies are needed to provide more evidence for clinical practice.

Investigation of the mechanism of dural arteriovenous fistula formation induced by high intracranial venous pressure in a rabbit model.

BACKGROUND: The causes of dural arteriovenous fistula have not been clearly defined. The aim of this study was to investigate the mechanism of dural arteriovenous fistula formation induced by high intracranial venous pressure using a rabbit model. RESULTS: By using rabbit model, dural arteriovenous fistula formation induced by high intracranial venous pressure could be produced by end-to-end and end-to-side anastomosis of the right side common carotid artery with the posterior facial vein plus ligation of the contralateral external jugular vein. As compared the post arteriovenous fistula formation among 1 week, 2 weeks, 3 weeks, and 90 days, the expression level of vascular endothelial growth factor in the 1- and 2-weeks groups was significantly higher compared with the control group, 3 weeks and 90 days groups (p ≤ 0.002). There was significantly higher hypoxia inducible factor-1α expression in the one week group compared with the control, 2 weeks, 3 weeks, and 90 days groups (p ≤ 0.002). The results of Western blotting showed that vascular endothelial growth factor expression level was highest in the 1 week group. The expression level of vascular endothelial growth factor was significantly different between all groups. CONCLUSIONS: The results of the experiments in our rabbit model indicate that high intracranial venous pressure is a key for dural arteriovenous fistula formation. Cerebral ischemia caused by lack of cerebral perfusion pressure plays a key role in the process that leads from high intracranial venous pressure to increased hypoxia inducible factor-1α expression and then increased vascular endothelial growth factor expression.

Surgical therapy for craniocerebral firearm injury.

AIM: The current study aims to explore the clinical characteristics of craniocerebral firearm injury and to improve the diagnosis and treatment of this condition. MATERIAL AND METHODS: Data from 56 patients with craniocerebral firearm injury were analyzed retrospectively for projectile types, traumatic conditions, and treatment approaches. RESULTS: 43 patients exhibited intracranial foreign body residence. Of them, 40 were subjected to complete foreign body removal and 2 to partial removal, leaving 1 without receiving removal treatment. 54 patients (96.4%) survived and 2 (3.6%) died. Of the survivors, 36 (64.3%) recovered well, 15 (26.8%) were moderately disabled, 2 (3.6%) were severely disabled, and 1 (1.8%) lapsed into vegetative state. Patients receiving debridement within 8 h after injury had a significantly higher recovery rate than those receiving such treatment after 8 h (82.1% vs. 26.7%; P < 0.001). CONCLUSION: Craniocerebral firearm injury is characterized by rapid traumatic condition development as well as serious trauma and contamination. Accurately judging the traumatic condition and the ballistic tract, performing complete debridement as early as possible, reasonably deciding on the operative mode and approach for intracranial residing foreign body removal, and increasing vigilance regarding concomitant injuries are the keys to the improvement of the overall treatment of craniocerebral firearm injury.

Clinical application of anatomy landmarks for microscopic endonasal transsphenoidal surgery for pituitary adenomas.

It is important to identify relevant anatomical landmarks on the route of endonasal transsphenoidal surgery (TSS) for pituitary adenomas to improve the gross total resection and the remission of disease. We therefore retrospectively studied the clinical outcomes of 148 patients who underwent single nostril endonasal TSS for pituitary adenomas. The anatomic basis of these procedures was evaluated. The important landmarks included the mucosal sphenoid ostia, the sphenoid keel, the osseous ostia and the nutrient arteries nearby, the sellar bulge, and the carotid protuberance, which outlined a clear route to the sella turcica with the best view and less tissue damage. Based on these landmarks, 148 cases of endonasal TSS were successfully performed to achieve 70.3% of gross total resection and remission, respectively. The complications were controlled to the least. Therefore, the application of these landmarks will help to prevent complications and improve the long-term outcomes.

Diagnostic Significance of Intracystic Nodules on MRI in Rathke's Cleft Cyst.

Background and Purpose. To explore strategies for the diagnosis and treatment of Rathke's cleft cyst (RCC). Methods. The medical records of 24 patients with sellar RCC were retrospectively reviewed. Two patients had concomitant pituitary adenoma, 2 underwent transcranial surgery, and 22 underwent transsphenoidal surgery. The clinical features, especially the findings of intracystic nodules on MRI, were evaluated and compared with the pathological findings. Results. Preoperatively, only 2 patients were diagnosed with RCC or suspected RCC. Pre- and postoperative MRI images revealed 10 intracystic nodules in 9 (37.5%) patients. Two nodules had bull's eyelike changes. The signal intensity of the intracystic nodules varied on T1- and T2-weighted images. Not all nodules on T2-weighted images were visualized. Postoperative MRI revealed recurrence or residual lesion in 5 patients; none had new symptoms and a second surgery was not required. Conclusions. Identifying intracystic nodules is important in patients with sellar cystic lesions. Bull's eyelike change in an intracystic nodule on MRI, which is reported here for the first time, potentially might have value for confirming the diagnosis.

Virtual reality surgical anatomy of the sphenoid sinus and adjacent structures by the transnasal approach.

OBJECTIVE: To examine the three-dimensional virtual anatomical features of the sphenoid sinus and adjacent structures during virtual surgery and explore their relevance to actual transsphenoidal surgery. METHODS: CT images of the sphenoid sinus and surrounding structures from 28 Chinese adult patients were measured using a 16-slice helical CT scanner. Image analysis was performed using the volume-rendering method. Two experienced neurosurgeons wearing stereoscopic glasses performed virtual transsphenoidal surgery by the transnasal approach. RESULTS: The virtual anatomical features of the sphenoid sinus and the adjacent structures during virtual surgery were described. The distance from the sphenopalatine foramen to the left and right sphenoid ostium was 10.1 ± 2.7 mm and 10.5 ± 3.2 mm, respectively, to the left and right sphenoidal crest 12.9 ± 2.0 mm and 12.8 ± 2.2 mm, respectively, and to the left and right uncinate process 24.0 ± 1.9 mm and 23.9 ± 2.0 mm, respectively. The distance from the uncinate process to the medial and lateral edge of the most prominent part of the anterior bend of the cavernous internal carotid artery (ICA) was 33.7 ± 3.7 mm and 34.8 ± 3.7 mm, respectively, and the angle between the two lines was 9.7 ± 1.9°. CONCLUSION: The study provides virtual anatomical information about the sphenoid sinus and important surrounding structures that is essential for successful real life transsphenoidal surgery.

The microanatomical structure of the cistern of the lamina terminalis.

Microanatomical dissection was performed on 14 formalin-fixed human cadaveric head specimens to provide information relevant for surgical procedures involving the cistern of the lamina terminalis (LT). The cistern of the LT was located in the midline of the telencephalon and was tent-shaped. The superior wall was located between the septal areas bilaterally, the lateral walls leaned laterally downwards, the anterior wall was the integrated line of the bilateral leptomeninges, the posterior and the inferoposterior walls were composed of the LT, the inferior margin was the arachnoid membrane between the optic nerves, and the inferoanterior wall usually formed a recess in front of the optic chiasm. In summary, the shape of the cistern of the LT is relatively constant, which is helpful for predicting the direction of hemorrhage of an aneurysm of the anterior communicating artery; in distinguishing its neural, vascular, and fibrous contents; and guiding surgical procedures.

Microsurgical anatomy of Liliequist's membrane demonstrating three-dimensional configuration.

OBJECT: Liliequist's membrane (LM) is an important arachnoid structure in the basal cisterns. The relevant anatomic descriptions of this membrane and how many leaves it has are still controversial. The existing anatomical theories do not satisfy the needs of minimally invasive neurosurgery. We aimed to establish the three-dimensional configuration of LM. METHODS: Fifteen adult formalin-fixed cadaver heads were dissected under a surgical microscope to carefully observe the arachnoid mater in the suprasellar and post-sellar areas and to investigate the arachnoid structure and its surrounding attachments. RESULTS: It was found that the LM actually consists of three types of membranes. The diencephalic membrane (DM) was usually attached by the mesencephalic membrane (MM) from underneath, and above DM it was usually a pair of hypothalamic membranes (HMs) extending superomedially. The pair of HMs was stretched between the DM (or MM) and the hypothalamus and were seldom attached to the carotid-chiasmatic walls between the carotid cistern and the chiasmatic cistern. These three types of membranes (DM, MM, and HM) comprised the main arachnoid structure in the anterior incisural space and often presented as four connected leaves. However, only two thirds of the specimens had all three types of membranes, and there was considerable variation in the characteristics and shapes of the membranes among the specimens. CONCLUSION: All three types of membranes comprising LM serve as important anatomical landmarks and interfaces for surgical procedures in this area.

Microanatomy and surgical relevance of the olfactory cistern.

All surgical approaches to the anterior skull base involve the olfactory cistern and have the risk of damaging the olfactory nerve. The purpose of this study was to describe the microanatomical features of the olfactory cistern and discuss its surgical relevance. In this study, the olfactory cisterns of 15 formalin-fixed adult cadaveric heads were dissected using a surgical microscope. The results showed that the olfactory cistern was situated in the superficial part of the olfactory sulcus, which separated the gyrus retus from the orbital gyrus. In coronal section, the cistern was triangular in shape; its anterior part enveloped the olfactory bulbs and was high and broad; its posterior part was medial-superior to internal carotid artery and was also much broader. There were one or several openings in the inferior wall of the posterior part in 53.4% of the cisterns. The olfactory cistern communicated with the surrounding subarachnoind cisterns through these openings. The middle part of the olfactory cistern gradually narrowed down posteriorly. Most cisterns were spacious with a few fibrous trabeculas and bands between the olfactory nerves and cistern walls. However 23% of the cisterns were narrow with the cistern walls tightly encasing the olfactory nerve. There were two or three of arterial loops in each olfactory sulcus, from which long, fine olfactory arteries originated. The olfactory arteries coursed along the olfactory nerve and gave off many terminal branches to provide the main blood supply to the olfactory nerve in most cisterns, but the blood supply was in segmental style in a few cisterns. Moreover, the veins of the cistern appeared to be more segmental than the olfactory arteries in most cisterns. These results suggested that most olfactory cisterns are spacious with relatively independent blood supply, and it is reasonable to separate the olfactory tract with its independent blood supply from the frontal lobe by 1-2 cm in the subfrontal approach, the pterional approach, or anterior interhemispheric approach. However, in the minority of cases, separation of the olfactory tract is not safe because of the anterior origin of the olfactory arteries or segmental blood supply. It is difficult to separate the olfactory nerve without any damage to the olfactory nerve, even with very skilled hands.