Intracranial nerve repair: a review of experimental and clinical studies

Trochlear Nerve Repair during Retrosigmoid Suprameatal Approach for Petrotentorial Meningioma: Operative Video

When operating on difficult skull base lesions, it is essential to be able to handle unexpected intraoperative findings or troubles, while achieving maximal lesion removal and minimal functional deficit. This video demonstrates a case of trochlear nerve repair that was performed during the retrosigmoid suprameatal approach for treatment of a petrotentorial meningioma, extending into the Meckel's cave. The patient is a 47-year-old woman with a right petrotentorial meningioma, extending into the Meckel's cave. The retrosigmoid suprameatal approach was performed with preservation of the superior petrosal vein. However, a divided trochlear nerve was incidentally found during tumor resection. We hence carefully dissected both nerve ends from the tumor without shortening their lengths, and repaired them by end-to-end anastomosis, using fibrin glue without any graft materials. The tumor was removed completely and the patient's preoperative facial sensory impairment disappeared after the surgery. The patient's facial sensory impairment disappeared completely, but she had transient diplopia after the surgery. However, the newly developed diplopia resolved completely, and she had no neurological deficits or tumor recurrence during the follow-up period of 1-year. The link to the video can be found at: https://youtu.be/g-B-w_zDudg .

Bilateral traumatic abducens nerve avulsion: A case series and literature review

Although abducens nerve palsy is an established sequela of head trauma - given the prolonged intracranial course of the nerve - bilateral injury is rare. Here, we present two cases of bilateral traumatic abducens nerve avulsion, in the absence of regional fractures, one of which presented two months following the initial trauma. Additionally, we review the current literature on bilateral abducens nerve palsy secondary to trauma, discussing the anatomy of the nerve's course and potential mechanisms of injury.

Sound-induced facial synkinesis following facial nerve paralysis

Facial synkinesis (or synkinesia) (FS) occurs frequently after paresis or paralysis of the facial nerve and is in most cases due to aberrant regeneration of (branches of) the facial nerve. Patients suffer from inappropriate and involuntary synchronous facial muscle contractions. Here we describe two cases of sound-induced facial synkinesis (SFS) after facial nerve injury. As far as we know, this phenomenon has not been described in the English literature before. Patient A presented with right hemifacial palsy after lesion of the facial nerve due to skull base fracture. He reported involuntary muscle activity at the right corner of the mouth, specifically on hearing ringing keys. Patient B suffered from left hemifacial palsy following otitis media and developed involuntary muscle contraction in the facial musculature specifically on hearing clapping hands or a trumpet sound. Both patients were evaluated by means of video, audio and EMG analysis. Possible mechanisms in the pathophysiology of SFS are postulated and therapeutic options are discussed.

Intracranial repair of a divided trochlear nerve. Case report

The authors report the case of a 37-year-old woman in whom the trochlear nerve was transected during removal of a meningioma in the cavernous sinus and subsequently repaired by using microsurgical techniques. This patient presented with a tumor in the posterior part of the right cavernous sinus with expansion over the tentorium. Preoperatively, she suffered from partial deficit of the right trochlear nerve. Intraoperatively, the trochlear nerve was noted to be completely encased by the tumor and was totally divided during removal of the lesion. After tumor resection, the trochlear nerve was repaired by using a sural nerve fascicle secured with sutures and fibrin glue. Six months after the operation, trochlear nerve regeneration became evident as the patient's binocular vision gradually improved. The patient regained normal functioning of the superior oblique muscle 3.5 years after surgery. It is concluded that repair of a divided trochlear nerve is worthwhile and can be followed by successful regeneration and an excellent functional recovery of the superior oblique muscle.