Charles E. Poletti

Treatment of trigeminal neuralgia and other facial pains by retrogasserian injection of glycerol.

Håkansons treatment of trigeminal neuralgia by injecting 0.2 to 0.4 ml of glycerol into the cerebrospinal fluid in Meckels cave was carried out in 27 patients with trigeminal neuralgia, 3 with atypical facial neuralgia, and 1 with post-traumatic facial neuralgia. Minor modifications of his technique are described based on our finding of a greater pain and sensory loss upon injection than he noted. We present evidence that glycerol is more toxic than its cryoprotectant effect would intimate and that it selectively eliminates those components of the compound action potential in the trigeminal rootlets customarily associated with pain. We conclude that the method is probably going to be an improvement over radiofrequency heating for the treatment of trigeminal neuralgia in many situations.

Edinger-Westphal nucleus: cholecystokinin immunocytochemistry and projections to spinal cord and trigeminal nucleus in the cat

Immunocytochemical methods were used to determine the distribution of cells with cholecystokinin-like immunoreactivity (CCK-LI) in the cat Edinger-Westphal complex (EW). Numerous cells with CCK-LI are found throughout the length of EW. The distribution and frequency of such cells are similar to the pattern of EW neurons that show substance P-like immunoreactivity (SP-LI). Companion retrograde transport experiments reveal that EW neurons which project to spinal cord or the region of the caudal trigeminal nucleus are found throughout the length of EW, and that some EW neurons which project to spinal cord also show CCK-LI.

Symptomatic Spinal Epidural Lipomatosis Associated with Cushing's Syndrome

In cases of Cushings syndrome, unusual amounts of fat may accumulate in the spinal epidural space, similar to centripetal fat deposits elsewhere in the body. The mass of excessive epidural fat may be responsible for neurological symptoms referable to compression of the spinal cord or cauda equina. We report three cases illustrating this unusual phenomenon and call attention to three cases reported previously. Although it is an unusual complication of Cushings syndrome, epidural lipomatosis should be considered in the differential diagnosis of any such case with neurological symptoms referable to the spinal cord or cauda equina. The diagnosis may be confirmed by computed tomographic scanning in conjunction with myelography. Therapeutic considerations are discussed.

Entrapment of the C2 root and ganglion by the atlanto-epistrophic ligament: clinical syndrome and surgical anatomy.

Two cases of progressive, occipital lancinating pain and dysesthesias associated with a sensory deficit of the C2 dermatome are presented. Symptoms were relieved, and C2 sensory function restored by releasing a hypertrophied atlanto-epistrophic ligament entrapping the C2 root and ganglion. The normal anatomy and abnormal surgical findings are described. C2 entrapment by the atlanto-epistrophic ligament is discussed in reference to other C2 lesions causing occipital pain. We conclude that some patients whose progressive occipital pain is accompanied by a C2 sensory deficit are suffering from entrapment of the C2 root and ganglion amenable to surgical decompression.

Proposed operation for occipital neuralgia: C-2 and C-3 root decompression. Case report.

The common association of occipital neuralgia with post-traumatic cervical arthritis raises the question of whether some cases of occipital neuralgia are due to delayed C-2 or C-3 root entrapment. This hypothesis led to surgical exploration of the C-3 and C-2 roots in a young patient with post-traumatic arthritic occipital neuralgia. The abnormal operative findings and resolution of the neuralgia after C-3 foraminal and C-2 fascial root decompression lead to the tentative proposal that some cases of occipital neuralgia represent a root entrapment syndrome amenable to neurosurgical decompression.

Edinger-Westphal neurons that project to spinal cord contain substance P

Combined retrograde transport and immunocytochemical methods were used to determine whether Edinger-Westphal neurons projecting to spinal cord also demonstrate substance P-like immunoreactivity (SPLI). Large injections of horseradish peroxidase (HRP) into cervical and lumbar enlargements retrogradely labeled cells throughout the length of the Edinger-Westphal complex (EW). Nearly all HRP-labeled EW neurons also stained for SPLI, evidence that EW is the origin of a direct substance P pathway linking rostral mesencephalon with spinal cord.

C2 and C3 pain dermatomes in man.

This report defines the C2 and C3 pain dermatomes by the distribution of: the hypalgesia clearing after surgical root decompression; the dysaesthesias produced by electrical root stimulation; and the hypalgesia produced by anaesthetic root block. The C2 pain dermatome, so defined, consists of an occipital parietal area 6–8 cm wide, ascending paramedially from the subocciput to the vertex. The C3 pain dermatome is a craniofacial area including the scalp around the ear, the pinna, the lateral cheek over the angle of the jaw, the submental region and the lateral and anterior aspects of the upper neck. These C2 and C3 pain dermatomes do not overlap and are smaller than the C2 and C3 tactile dermatomes described in the literature.

Amygdalospinal projections in the cat

Spinal cord injections of rhodamine-labeled fluorescent latex microspheres in the cat resulted in retrograde labeling of a dense, well-defined group of neurons within the central nucleus of the amygdala and a modest number of neurons in the medial nucleus. Amygdalospinal neurons were found to be large cells of variable shape and orientation that were distributed bilaterally with an ipsilateral predominence.

Dangerous Rises in Blood Pressure upon Heating of Trigeminal Rootlets; Increased Bleeding Times in Patients with Trigeminal Neuralgia

During radiofrequency (RF) heating of trigeminal rootlets, we regularly measured blood pressure rises to 250 to 300 mm Hg, confirming two previous reports. We also found abnormally increased bleeding times in 12% of 127 patients awaiting operation for trigeminal neuralgia. These two facts probably explain 6 fatalities and 2 lasting hemiplegias from intracranial bleeding unrelated to vascular puncture by the needle electrode during RF procedures for trigeminal neuralgia. We recommend correction of the abnormal bleeding time and control of the blood pressure rises by i.v. sodium nitroprusside.

Hippocampal influence on amygdala unit activity in awake squirrel monkeys

The influence of hippocampal electrical stimulation on amygdala extracellular unit activity was studied in the awake squirrel monkey. Hippocampal influence was topographically organized. Stimulation elicited responses in 20% of 476 units tested. Ipsilateral anterior stimulation was more effective than posterior or contralateral stimulation. In the 6 areas with more than 25 tested units, the basomedial nucleus had the highest percentage of responsive units (39%), followed by the accessory basolateral (33%), central (22%y, basolateral (21%), and lateral (5%) nuclei, and the anterior amygdala area (4%). Initial excitation (E) was more prevalent than initial inhibition (I) in the central (90% E vs 10% I) and basomedial (82% E vs 18% I) nuclei; but initial inhibition was more common in basolateral (37% E vs 63% I) and accessory basolateral (33% E vs 67% I) nuclei. The mean response latency was 30.8 msec, ranging from 12 to 130 msec. The basomedial nucleus appears to receive the most potent hippocampal influence. Response characteristics are consistent with a hypothesized relay of nonfornix hippocampal influences on basal forebrain and hypothalamus via the basomedial nucleus. Possible pathways of hippocampal influence and the implications of our results for concepts of hippocampal and amygdala function are discussed.