Baohui Feng

Clear cell meningioma: clinical features, CT, and MR imaging findings in 23 patients.

Background Clear cell meningioma (CCM) is a rare meningioma, with radiologic features not well characterized in literature. The purpose of this study was to describe and characterize the clinical features and imaging findings of CCM. Materials and Methods The computed tomography (n = 16) and magnetic resonance (n = 23) images of 23 patients (12 men and 11 women; mean age, 34.6 years) were retrospectively reviewed. All of the patients underwent surgical resection. Follow-up was performed through clinical observations. Results Cerebellopontine angle was the most frequently presenting location (n = 10). The tumors were isointense (n = 12) or hypointense but associated with isointense (n = 7) appearance to gray matter on T1-weighted images. However, the tumors seemed to be isointense (n = 6) or isointense and hyperintense (n = 13) on T2-weighted images. On gadolinium-enhanced T1-weighted images, heterogeneous enhancement was seen in 14 lesions. Four lesions had amorphous calcifications, 18 showed peritumoral edema, 14 had cystic areas, 2 had bone hyperostosis, and 8 manifested bone destruction. On initial surgery, 17 patients underwent complete resection, whereas 5 patients underwent subtotal resection of their tumors. The operative result for the remaining patient was unknown. Follow-up was possible in 22 patients. Eleven patients had recurrence and 2 had died. Conclusions Clear cell meningioma is a rare subtype of meningioma that occurs in younger patients and often recurs. Cerebellopontine angle is the most affected area in this series. The extent of initial surgical resection is the most important prognostic factor. In radiological studies, CCM tends to have marked heterogeneous enhancement, prominent peritumoral edema, intratumoral cystic components, and involvement of the adjacent bone.

Hemifacial spasm caused by cross type vascular compression

Abstract Objectives: The meatal segment of anterior inferior cerebellar artery usually crosses over the gap between cranial nerves VII and VIII, and may compress the cisternal portion (CP) of the facial nerve. This is defined as cross type compression, which is easy to be neglected and thus leads to poor outcome. Here our experience in treating patients of cross type hemifacial spasm (HFS) is reported. Methods: Twenty-one patients of HFS due to cross type compression were treated with microvascular decompression (MVD) surgery with the aid of abnormal muscle response monitoring. Results: In addition to cross type compression at CP, there were typical vascular compressions on the root exit zone and attached segment in 20 cases. After MVD surgery, 17 patients were cured, 3 patients achieved good resolution of spasm, and the other 1 patient got delayed resolution. Three patients had postoperative transient hearing loss and/or tinnitus. Discussion: Even there are apparently typical vascular compressions at proximal portion of the facial nerve, the surgeon should be aware that cross type compression at the CP may co-exist. With the aid of abnormal muscle response (AMR) monitoring, MVD is efficient for patients due to cross type compression.

Management of different kinds of veins during microvascular decompression for trigeminal neuralgia: technique notes

Objective: During microvascular decompression surgery for trigeminal neuralgia, surgeons will encounter various kinds of veins that block the approach to or compress the trigeminal nerve. The aim of this study was to present our experience in managing different kinds of veins. Methods: This was a retrospective study of 21 patients with trigeminal neuralgia, in whom one or more veins were encountered during surgery. The techniques used in treating 4 types of veins during microvascular decompression were assessed, and the surgical outcomes and operative complications were analysed. Results: For the first type, large veins blocking the approach towards the root entry zone (REZ) of the trigeminal nerve were bypassed via cerebellar fissure approach. Second, veins lying on the brainstem surface and compressing the REZ were detached using a gelatin-assisted dissecting technique and then interposed. Third, veins rising from the surface of the brainstem and crossing the cisternal portion of the trigeminal nerve were interposed. Fourth, intraneural veins, which were generally small, were coagulated and cut. In this series, there was no intentional sacrifice or unintentional rupture of large veins, and the sacrifice rate of medium and small veins was only 19.0%. Thirteen patients (61.9%) gained complete pain relief immediately after surgery (i.e. “excellent” result), while the remaining eight patients (38.1%) achieved “good” pain relief. Conclusion: Different surgical techniques were used based on the different kinds of veins encountered. This allowed preservation of almost all the large veins. There were no serious complications postoperatively.

Experimental Study on the Effect of Electrostimulation on Neural Regeneration After Oculomotor Nerve Injury

The oculomotor nerve can regenerate anatomically and histologically after injury; however, the degree of functional recovery of extraocular muscles and the pupil sphincter muscle was not satisfactory. Electrostimulation was one potential intervention that was increasingly being studied for use in nerve injury settings. However, the effect of electrostimulation on regeneration of the injured oculomotor nerve was still obscure. In this study, we studied the effects of electrostimulation on neural regeneration in terms of neurofunction, myoelectrophysiology, neuroanatomy, and neurohistology after oculomotor nerve injury and found that electrostimulation on the injured oculomotor nerve enhanced the speed and final level of its functional and electrophysiological recovery, promoted neural regeneration, and enhanced the selectivity and specificity of reinnervation of the regenerated neuron, the conformity among the electrophysiological and functional recovery of extraocular muscles, and neural regeneration, and that the function of extraocular muscles recovered slower than electrophysiology. Thus, we speculated that electrostimulation on the injured oculomotor nerve produced a marked effect on all phases of neural regeneration including neuronal survival, sprout formation, axonal elongation, target reconnection, and synaptogenesis. We think that neural electrostimulation can be used in oculomotor nerve injury.

Good Surgical Outcomes of Hemifacial Spasm Patients with Obvious Facial Nerve Indentation and Color Change

OBJECTIVES Hemifacial spasm results from vascular compression of the facial nerve. It remains controversial whether severe compression and subsequent nerve indentation predict a good or a poor surgical outcome. Here, to illustrate the relationship between the degree of neurovascular compression and surgical outcome, we conducted a retrospective case-cohort study focused on patients whose facial nerve was seriously compressed. METHODS This study included 2 groups. The nerve-indentation group included 48 patients with hemifacial spasm whose facial nerves had obvious indentation and color change at the site of neurovascular conflict. The control group included 48 randomly selected patients with hemifacial spasm without facial nerve indentation or color change who were surgically treated by the same team during the same period. The surgical findings, intraoperative lateral spread response results, and clinical outcomes were compared. RESULTS Single-vessel compression was found more frequently in the nerve-indentation group (87.5%) than in the control group (60.4%, P < 0.05). The lateral spread response (LSR) resolution rate of the nerve-indentation group was 91.7%, and that of the control group was 87.5% (P > 0.05). The rates at which the microvascular decompression procedure was successful were equal in the nerve-indentation and the control groups (93.8% vs. 91.7%, P > 0.05). CONCLUSIONS Severe vascular compression and subsequent nerve indentation were correlated with a greater possibility of single compression and a lower incidence of multiple neurovascular conflicts in patients with hemifacial spasm, making the microvascular decompression procedure more accurate and easier. Therefore nerve indentation might predict good surgical outcomes.

Balloon-Assisted Fistula Sealing Procedure for Symptomatic Tarlov Cysts

OBJECTIVE Tarlov cyst is an abnormal expansion of the spinal nerve sleeve, and it communicates with the subarachnoid cavity via a perineural fistula. This study presents our experience of a balloon-assisted fistula sealing procedure in treating Tarlov cyst. METHODS Twenty-two patients with symptomatic Tarlov cysts were surgically treated. An emulsion balloon was placed into the lumbar subarachnoid cistern through a trocar, so as to temporarily block cerebrospinal fluid flow, then the thecal sac was opened and the inlet of the fistula was sealed by suture of a muscular patch and reinforced by fibrin glue. Finally, the cyst wall was imbricated and the bony cavity was filled with pedicled muscle flaps. RESULTS Comparing the preoperative and postoperative pain scores according to visual analog scale, 2 patients were slightly improved and 18 patients were substantially improved, including 3 completely pain-free cases. Only 2 patients were unchanged in pain, and both of them had multiple cysts. As a whole, the postoperative pain score was much better than the preoperative score (2.4 vs. 7.5; P < 0.01). Bladder weakness was slightly improved, and bowel dysfunction was almost unchanged after operation. During follow-up, cyst recurrence was found in 1 patient. CONCLUSIONS The balloon-assisted fistula sealing procedure is safe and effective for Tarlov cyst, especially for the single cyst. It is a good complement to the cyst wall imbricating procedure.

Microvascular Decompression for Trigeminal Neuralgia: Zone Exploration and Decompression Techniques.

Objective:The aim of this study is to introduce zone exploration of the trigeminal nerve and decompression techniques for different types of vasculars. Methods:The trigeminal nerve was sectioned into 5 zones. Zone 1, 2, 3, 4 was located at the rostral, caudal, ventral, and dorsal part of the nerve root entry zone (REZ) respectively, and zone 5 was located at the distal of the nerve root. This study contained 86 patients with trigeminal neuralgia underwent microvascular decompression. Every zone was exposed through preoperative imaging. During the operation, offending vessels were explored from zone 1 to zone 5, and different decompression techniques were used for different types of vessels. Results:Through zone exploration, the sensitivity of preoperative imaging was 96.5% and specificity was 100%. Location of the neurovascular conflict was in the zone 1 in 53.5% of the patients, zone 2 in 32.6%, zone 3 in 45.3%, zone 4 in 29.1%, and zone 5 in 34.9%. In total, 2 zones were both involved in 59.3%, and 3 zones were involved in 18.6%. All offending arteries were moved away and interposed with Teflon sponge. Offending veins of 11 patients were too small to interpose, and coagulated and cut was adopted. The other offending veins were interposed with wet gelatin and Teflon sponge, respectively. Conclusions:Zone exploration is helpful in finding offending vessels and adequate decompression can be achieved by choosing different methods according to different types of offending vessels.

A standardized method to create peripheral nerve injury in dogs using an automatic non-serrated forceps

This study describes a method that not only generates an automatic and standardized crush injury in the skull base, but also provides investigators with the option to choose from a range of varying pressure levels. We designed an automatic, non-serrated forceps that exerts a varying force of 0 to 100 g and lasts for a defined period of 0 to 60 seconds. This device was then used to generate a crush injury to the right oculomotor nerve of dogs with a force of 10 g for 15 seconds, resulting in a deficit in the pupil-light reflex and ptosis. Further testing of our model with Toluidine-blue staining demonstrated that, at 2 weeks post-surgery disordered oculomotor nerve fibers, axonal loss, and a thinner than normal myelin sheath were visible. Electrophysiological examination showed occasional spontaneous potentials. Together, these data verified that the model for oculomotor nerve injury was successful, and that the forceps we designed can be used to establish standard mechanical injury models of peripheral nerves.