Treatment of chronic pain by epidural spinal cord stimulation: a 10-year experience

Epidural spinal cord stimulation by means of chronically implanted electrodes was carried out on 121 patients with pain of varied benign organic etiology. In 116 patients, the pain was confined to the back and lower extremities and, of these, 56 exhibited the failed-back syndrome. Most patients were referred by a pain management service because of failure of conventional pain treatment modalities. Electrodes were implanted at varying sites, dictated by the location of pain. A total of 140 epidural implants were used: 76 unipolar, 46 Resume electrodes, 12 bipolar, and six quadripolar. Patients were followed for periods ranging from 6 months to 10 years, with a mean follow-up period of 40 months. Forty-eight patients (40%) were able to control their pain by neurostimulation alone. A further 14 patients (12%), in addition to following a regular stimulation program, needed occasional analgesic supplements to achieve 50% or more relief of the prestimulation pain. Pain secondary to arachnoiditis or perineural fibrosis following multiple intervertebral disc operations, when predominantly confined to one lower extremity, seemed to respond favorably to this treatment. Uniformly good results were also obtained in lower-extremity pain secondary to multiple sclerosis. Pain due to advanced peripheral vascular disease of the lower limbs was well controlled, and amputation below the knee was delayed for up to 2 years in some patients. Pain due to cauda equina injury, paraplegic pain, phantom-limb pain, pure midline back pain without radiculopathy, or pain due to primary bone or joint disease seemed to respond less well. Patients who responded to preliminary transcutaneous electrical nerve stimulation generally did well with electrode implants. Notable complications included wound infection, electrode displacement or fracturing, and fibrosis at the stimulating tip of the electrode. Three patients in this series died due to unrelated causes. Epidural spinal cord stimulation has proven to be an effective and safe means of controlling pain on a long-term basis in selected groups of patients. The mechanism of action of stimulation-produced analgesia remains unclear; further studies to elucidate it might allow spinal cord stimulation to be exploited more effectively in disorders that are currently refractory to this treatment modality.     

The effect of mannitol on cerebral white matter water content

The authors have studied the effect of a low-dose (0.28 gm/kg) bolus infusion of mannitol on brain water in man. In eight patients with severe head injury, small pieces of subcortical white matter were taken at craniotomy both before and after infusion of mannitol. The tissue specific gravity was measured using a graduated specific-gravity column, and from it the brain water content was calculated. White matter specific gravity rose from a mean (+/- standard error of the mean) of 1.0325 +/- 0.0012 before mannitol infusion to 1.0352 +/- 0.0011 after mannitol administration, and the brain water content fell from a mean of 80.94% +/- 2.5% to 75.28% +/- 2.3%. The differences were significant (p less than 0.01). This study shows that, after head injury in man, mannitol increases the white matter specific gravity and probably does so by reducing brain water.     

Desmoplastic infantile ganglioglioma with calcification

Desmoplastic infantile gangliogliomas (DIGs) are rare intracranial, cystic tumors, usually detected within the first 2 years of life. Histologically, these tumors are characterized by intense desmoplasia and a divergent astrocytic and neuronal differentiation. Less than 60 well‐documented cases of this extremely rare tumor are reported in the literature. We present the case of a 10‐month‐old male child presenting with a large, cystic, intracranial lesion and having the characteristic histological features of a DIG. In addition, the lesion also showed focal areas of calcification within the tumor, not usually considered a feature of this entity. The present case extends the reported spectrum of this rare entity and describes the unusual occurrence of calcification within the lesion.