Use of a novel ultrasonic surgical system for decompression of the facial nerve

OBJECTIVE: The middle cranial fossa approach has been used to explore and decompress the facial nerve in patients with Bell's palsy and facial nerve tumors. Unfortunately, this approach is technically challenging and has a significant risk of injury to the facial nerve and to the cochleovestibular organs. One way to minimize the risk may be with the use of the Sonopet Omni ultrasonic aspirator (Synergetics Inc., St Charles, MO) instead of an otologic drill. METHODS: In this prospective study using cadaveric temporal bones, a total of 17 temporal bone specimens were used. Seven cadaveric temporal bones were used (4-left, 3-right) for the initial feasibility study. At a second session, an additional 10 temporal bones (5-left, 5-right) underwent decompression of the facial nerve from the fundus of the internal auditory canal (IAC) to the geniculate ganglion (ie, labyrinthine segment). The average time to decompress the labyrinthine segment was measured. The temporal bones were then examined for evidence of any injury. RESULTS: None of the 17 temporal bones showed any sign of injury to the superior semicircular canal or the cochlea. However, one specimen did have penetration of the IAC dura; another specimen did have penetration of the epineurium of the facial nerve. However, in neither case was there any evidence of injury to the facial nerve itself. At the first session, the average time for decompression of the labyrinthine segment was 10 minutes and 12 seconds. At the second session, the average time for decompression was 5 minutes and 0 seconds. CONCLUSION: The ultrasonic surgical system may be used as an alternative to the surgical drill for decompression of the facial nerve. Although a learning curve does exist, as with any new surgical tool or device, our results indicate that the device can be used safely and in a reasonable amount of time. However, before proceeding with intraoperative use of this device for otologic and neurotologic procedures, familiarization is first recommended on cadaveric temporal bone specimens.     

Gomez-Lopez-Hernandez syndrome

We describe a case of Gomez-Lopez-Hernandez syndrome in an 18-month-old boy. Imaging findings included rhombencephalosynapsis with a single dentate nucleus. In addition, MR angiography revealed an azygous anterior cerebral artery. The clinical presentation, MRI findings and pathogenesis are discussed.     

关节镜术诊断与治疗退行性股骨髁间窝前交叉韧带撞击症

目的:报道退行性股骨髁间窝前交叉韧带撞击症14膝.作者对关节镜在本病诊断中的优点、分型及治疗方法进行探讨.方法:所有病人均合并骨性关节炎,男5膝,女9膝;左侧8膝,右侧6膝.主要表现为膝关节前部或定位不确定的钝痛、渐进性关节伸屈障碍和反复关节积液.关节镜术野良好,可动态检查前交叉韧带在运动中所受阻碍的情况,提高本病诊断率并有助于分型,关节镜下可将本病分为三型:磨损型、挤夹型、混合型.治疗采用关节镜下股骨髁间窝扩大成形术加镜下关节清理术.结果:随访13例,平均18个月,术后关节功能均超过术前水平,尤其关节伸屈功能障碍改善明显,目前尚无复发需再次手术者.结论:关节镜术对本病的诊断与治疗益处颇多,关节镜下股骨髁间窝扩大成形术是治疗本病的良好方法.     

额颞耳前联合断颧弓颞下入路切除中颅窝底鞍旁肿瘤临床研究

目的　探讨额颞耳前联合断颧弓颞下入路切除中颅窝底鞍旁肿瘤的疗效和体会。方法　对术前确诊为中颅窝底鞍旁肿瘤的 5例病人 ,采用术中切断颧弓将颞肌瓣翻下 ,显露颞窝 ,使骨窗接近颅底 ,充分暴露肿瘤和鞍旁的相关解剖关系。结果　本组 3例全切除 ,2例近全切除 ,无并发症发生。结论　用此方法切除中颅窝底鞍旁肿瘤可达到最大范围的肿瘤切除 ,避免了周围神经、血管的损伤 ,保全了脑组织的正常生理功能。     

Cranial nerve lesions and abnormal visually evoked potentials associated with the M694V mutation in familial Mediterranean fever

A 52-year-old Turkish man with familial Mediterranean fever (FMF) due to the homozygous M694V mutation in the MEFV-gene on chromosome 16p13.3, newly developed hemicrania, blurred and double vision, ptosis, ophthalmoparesis and peripheral facial nerve palsy. Except for double vision, all the other abnormalities disappeared spontaneously within 10 days after onset. Markedly prolonged latencies of the visually evoked potentials were also found. At follow-up, 8 months after onset of the neurological abnormalities, right-sided bradydiadochokinesia, right-sided discrete weakness and right-sided hypaesthesia were found. After the exclusion of other hereditary fever syndromes, migraine, stroke, Molaret's meningitis, Beh?et's syndrome and mitochondriopathy by clinical, serological, CSF investigations, funduscopy, electroencephalography, and cerebral MRI and MRI angiography, the described neurological abnormalities were regarded as CNS and PNS manifestation of vasculitis or amyloidosis in FMF.     

Localization of the Internal Maxillary Artery for Extracranial-to-Intracranial Bypass through the Middle Cranial Fossa: A Cadaveric Study

The internal maxillary artery (IMAX) is a promising arterial pedicle to function as a donor vessel for extracranial-to-intracranial (EC-IC) bypass procedures. The access to the IMAX through the anterior portion of the middle cranial fossa floor allows a much shorter interposition graft to be used to create a bypass to the ipsilateral middle cerebral artery and prevents a second incision in the neck. One of the challenges of this technique, however, is the difficulty to find the IMAX through an intracranial approach. The purpose of this cadaveric study is to establish a reliable method to localize the IMAX through a middle fossa floor approach based on skull base bone landmarks. In this study 5 latex-injected fixated cadaveric specimens were dissected bilaterally (providing a total of 10 IMAX dissections) to determine the precise location of the IMAX in the pterygopalatine fossa in relationship to bone landmarks of the middle fossa floor as seen through an intracranial approach. Drilling of the middle fossa floor was undertaken through both the originally described “anteromedial” approach, and a new “anterolateral” approach. Measurements were taken correlating the position of the IMAX to ipsilateral foramen rotundum, ipsilateral foramen ovale, posterior wall of the maxillary sinus, and distal V2 branches. Median and standard deviation were calculated for each dataset. The IMAX was found, within the pterygopalatine fossa, by drilling the greater wing of the sphenoid bone on average 10 mm anteriorly and 5 mm laterally to foramen rotundum, at an average depth of 8 mm. The IMAX was also found inferiorly to the maxillary nerve and laterally to the pterygoid head of the lateral pterygoid muscle. A more laterally oriented approach, consisting of drilling the greater wing of the sphenoid bone from a point perpendicular to foramen rotundum posteriorly to the sphenotemporal suture anteriorly, allowed for a longer segment of the IMAX to be easily identified and exposed facilitating its use as a donor vessel in bypass procedures. This cadaveric study provides a reliable and reproducible set of measurements to localize the IMAX within the pterygopalatine fossa through an intracranial middle fossa approach. The ability to find the IMAX consistently is an important step in exploring the possibility of using the IMAX as a routine donor vessel for EC-IC bypass procedures.     

Improving intraoperative evoked potentials at short latency by a novel neuro-stimulation technology with delayed return discharge

ObjectiveThe intraoperative monitoring of cranial nerve function records evoked responses at latencies of a few milliseconds. Unfortunately, these responses may be masked by the electrical artifact of the stimulation pulse. In electrical stimulation, the return discharge of the stimulation pulse significantly contributes to the width of the electrical artifact.MethodsWe have generated stimulation pulses with an ISIS Neurostimulator (inomed Medizintechnik GmbH) providing a novel stimulation artifact reduction technique. It delays the return discharge of the stimulating pulse beyond the latency of the expected physiological response. This delayed return discharge is controlled such that no unintended physiological response is evoked.ResultsIn 21 neurosurgical interventions with motor evoked potentials of the facial nerve (FNMEP), the stimulation method generated a stimulation pulse artifact with reduced tail duration. Compared to conventional stimulation with immediate return discharge, the signal-to-noise ratio of the physiological response may improve with the novel stimulation method. In some surgeries, only the novel stimulation method generated clearly identifiable response signals.ConclusionsThe reduced width of the stimulation artifact extends the toolbox of intraoperative monitoring modalities by rendering the interpretation of cranial nerve evoked potentials more reliable.SignificanceThe novel technique enhances the number of patients for whom intraoperative monitoring may aid in cranial neurosurgery.     

Development of the Micro Architecture and Mineralization of the Basilar Part of the Pig Occipital Bone

In this study, the development of the architecture and the degree and distribution of mineralization in the basilar part of the pig occipital bone, one of the contact points between the spine and skull base, was investigated. Multiple regions of the basiocciput of pig specimens of different gestational ages were examined with three-dimensional microcomputed tomography (microCT). The cortex of the basilar part developed from a structure with a large intertrabecular separation into a more compact one, whereas its center maintained a trabecular structure. The cortex displayed a significant increase in bone volume fraction with age, together with an increase in trabecular thickness. In the center no change in bone volume fraction was observed, because of a combined decrease in trabecular number and increase in trabecular separation. During development the degree of mineralization was almost identical in both the center and the cortex and it tended to increase with age. This chance was, however, insignificant. The distribution of mineralization within the trabecular elements of both regions demonstrated that the cores of the elements were more highly mineralized than their surfaces. This difference in mineralization confirms the preexisting notion that trabecular elements grow in size due to surface apposition of new bone that initially is less mineralized.