Clinical Anatomy And Electrophysiological Study Of Trigeminal Nerve Root

Part Ⅰ The microscopic anatomic observation of trigeminal nerveroot by Sigmoid sinusPurposeObserving the trigeminal nerve root and its surrounding structures under a microscopeby sigmoid sinus, to identify the sensory root,motor rootlets,then guiding themicrovascular decompression surgery.Materials and MethodsPatients collected Guangdong NO.2Provincial People’s Hospital of Neurosurgerymicrovascular decompression from March2012to December2013admitted to theline of220cases, including120cases of trigeminal neuralgia (TN) as theexperimental group and100cases of primary idiopathic hemifacial spasm (HFS) asthe control group. Sigmoid sinus surgery through the posterior approach, in thesurgery, observing the relationship between the vessels and the trigeminal nervepoints clear of oppression, oppression and non-contact three categories.The obviousoppression type and contact type are belong to vascular compression group.surgeryunder a microscope to trigeminal sensory root into eight areas: I was outside of thearea, II as outside the region, III as the area within the zone IV, V as the medialarea, the lower zone VI, VII as the lower zone, VIII as the outside the lower area.Exploration and recording the relationships and types of vessels and the trigeminalnerve root, there isn’t any difference between the two sets of comparative analysis ofpatients with vascular compression of the trigeminal nerve statistical responsibilitiesdirection. Then, from each of two groups of patients were randomly selected20casesof trigeminal nerve stem angle, the sensory root and motor root of trigeminaldetailed observations and measurements, compared two groups of patients there is nodifference in the trigeminal nerve stem angle, while results feeling taproot length,width, thickness, etc. detailed data, and records the positional relationship betweenmovement and sensory root of the root. The last recorded surgical field exposureaffect the structure of the bridge before the pool, rock bone, rock vein. All patients underwent magnetic resonance angiography of the magnetic resonance angiography(MRA) examination of head to exclude cerebellopontine angle secondary lesions,while excluding past had undergone gamma knife,operation on trigeminal nerve root,such as selective rhizotomy surgery patients.Result1.Intraoperative vascular compression of the trigeminal nerve, trigeminal vascularcompression rate group (81.7%) was significantly higher than the group hemifacialspasm vascular compression rate (8%).2.The group had98cases of trigeminal vascular compression of (81.7%), including5cases of two arteries oppression, one case of three arteries oppression, three cases ofarteriovenous joint oppression, pure cava two cases, Total recorded offending vessels108. Responsibility vessels, the superior cerebellar artery is the primaryresponsibility of the blood vessels, there are82cases (75.9%), and more commonside oppression; followed by the anterior inferior cerebellar artery,13cases(12.0%), mainly from the oppression of the bottom of the trigeminal nerve;vertebrobasilar artery in7cases (6.5%), and more from the inside trigeminal nerveroot; rock cava four cases (3.7%), and more from the outside of the trigeminalnerve root compression of the trigeminal nerve. Other responsibilities Bridge arterialblood vessels and other small branch artery in2patients (1.9%).3.No two patients trigeminal brainstem angle difference angle ranges are10-80°, andthe majority of30-50°.4.Two groups of patients with trigeminal sensory root length, width, thicknessundifferentiated, its length is12.8±1.5mm, width of3.5±0.6mm, thickness2.7±0.3mm;5.The surgery can be recorded to a separate motor root of the trigeminal nerve (ordifferent line of sensory root) the number of filaments is3-14bar diameter of0.3-1mm, issued separately from the pons, issuing point is located inside the mainroot feeling inside and below the top, accompanied with the feeling taproot intoMeckel’s pouch. The root of the root of the existence of consistent movement, thereare also consistent movement between the root and the sensory root. 6.By the anatomy and medical ethics restrictions, feeling unable to separate the1,2,3branched taproot, can not distinguish different line of sensory root and rootmovement.Conclusion1.Vascular compression is one of the causes of trigeminal neuralgia; bridge beforethe pool is small, rock uplift constraints observed for bone trigeminal nerve root andMeckel’s pouch.2.According to the form roots movement, the point of origin, distribution andrelationship with the feeling taproot that can accurately identify microscopic motorroot of the trigeminal nerve, and protected.Part Ⅱ The physiological study of trigeminal nerve rootPurposeBy electrophysiological monitoring, to identify trigeminal sensory fibers, motorfibers, aberrant rootlet.Then researching the distribution of the trigeminal nerve rootconduction fibers.Materials and MethodsAfter collecting31cases of sigmoid sinus approach in patients with microvasculardecompression surgery,18cases of trigeminal neuralgia patients (experimentalgroup),13patients with primary hemifacial spasm patients (control group).Anatomic feeling isolated intracranial trigeminal nerve root, motor branch (differentline of fiber fineness); surgery will feel taproot is divided into eight regions eachgiven0.2mA current stimulation. Wherein I, II, VIII sensory area of the outer root, III,VII of the central region, IV, V, VI to the inside. The peripheral supraorbital foramen,infraorbital foramen, mental foramen record V1, V2, V3compound nerve actionpotential (CNAP), recorded in the masseter and temporalis muscles of the compoundmuscle action potential (CMAP); to stimulate the emergence of complex nerve actionwhen regional potential (CNAP) for sensory nerve fibers to stimulate the emergenceof regional when compound muscle action potential (CMAP) for motor nerve fibers; compare two groups of patients, there is no difference in the distribution of nervefibers; Finally, according to the composite and compound muscle action potential ofnerve determine the frequency of action potentials arise trigeminal nerve rootfunctional fibers (sensoryfibers, motor fibers) of distribution space.Result1. Stimulation of the trigeminal nerve root, all cases can the peripheral supraorbitalforamen, infraorbital foramen, mental foramen recorded at a stable complex nerveaction potentials recorded from a stable compound muscle action potential in themasseter and temporalis muscles Department;2. When stimulated sensory root, mainly recorded for compound nerve actionpotential;3.Stimulation or sensory root root movement inside, you can record the masseter and(or) temporal muscle compound muscle action potential, accompanied by V1, V2, V3in one or more of the compound nerve action potential; but stimulate movement rootresulting compound muscle action potential amplitude (60-90uV) higher than theinner root sensory stimulation produced compound muscle action potential amplitude(30-60uV);4.Stimulate different line when sensory root, peripheral nerve action potentialsrecorded less complex and compound muscle action potential, but not all cases can befound in the presence of accessory sensory fibersConclusion1.The use of composite nerve action potentials and compound muscle action potentialcan help identify the feeling of the trigeminal nerve root,motor rootlets and accessorysensory fibers, to avoid damage the motor rootlets.2.Motor root stimulation, electrical signals in the trigeminal ganglia can begeneralized to the peripheral sensory nerve roots, combined with clinical casesobserved speculated trigeminal motor fibers involved in the occurrence anddevelopment of trigeminal neuralgia.