Prem K. Pillay

Symptomatic Chiari malformation in adults: a new classification based on magnetic resonance imaging with clinical and prognostic significance.

Thirty-five consecutive adults with Chiari malformation and progressive symptoms underwent surgical treatment at a single institution over a 3-year period. All patients underwent magnetic resonance imaging scan before and after surgery. Images of the craniovertebral junction confirmed tonsillar herniation in all cases and allowed the definition of two anatomically distinct categories of the Chiari malformation in this age group. Twenty of the 35 patients had concomitant syringomyelia and were classified as Type A. The remaining 15 patients had evidence of frank herniation of the brain stem below the foramen magnum without evidence of syringomyelia and were labeled Type B. Type A patients had a predominant central cord symptomatology; Type B patients exhibited signs and symptoms of brain stem or cerebellar compression. The principal surgical procedure consisted of decompression of the foramen magnum, opening of the fourth ventricular outlet, and plugging of the obex. Significant improvement in preoperative symptoms and signs was observed in 9 of the 20 patients (45%) with syringomyelia (Type A), as compared to 13 of the 15 patients (87%) without syringomyelia (Type B). Postoperative reduction in syrinx volume was observed in 11 of the 20 patients with syringomyelia, including all 9 patients with excellent results. Magnetic resonance imaging has allowed a classification of the adult Chiari malformation in adults based on objective anatomic criteria, with clinical and prognostic relevance. The presence of syringomyelia implies a less favorable response to surgical intervention.

Radiofrequency Cingulotomy for Intractable Cancer Pain Using Stereotaxis Guided by Magnetic Resonance Imaging

This study presents a new and simplified method of creating cingulate gyrus lesions by using stereotaxis guided by magnetic resonance imaging (MRI). Previous methods have utilized ventriculogram-guided stereotaxis requiring indirect cingulate gyrus localization and general anesthesia. With the present technique a BRW stereotactic frame was applied with the patient under local anesthesia. An MRI scan was performed using a T1 signal (TR, 600 ms; TE, 30 ms) in the coronal plane with 5-mm thick sections spaced every 6 mm. The coronal slice 24 mm posterior to the anterior tip of lateral ventricle was identified. The center of each (right and left) cingulate gyrus was identified as a target area, and appropriate coordinates were determined. Approach parameters were calculated for the right and left gyri using an azimuth of 45 degrees and 315 degrees, respectively, and a declination of 45 degrees. A radiofrequency electrode was stereotactically placed so that the electrode tip was at a target point which was the center of the cingulate gyrus. A radiofrequency lesion (75 degrees, 60 seconds) was made in each hemispheres cingulate gyrus. Four patients with intractable terminal cancer pain have been initially treated in this manner. The lesions were well-localized on postoperative MRI scans. There have been no complications except for perilesional edema for 10 days in 1 patient (treated with longer radiofrequency settings that have subsequently been modified).(ABSTRACT TRUNCATED AT 250 WORDS)

Current Management of Choroid Plexus Carcinoma in Children

Eleven children with choroid plexus carcinoma are reviewed with respect to presentation, radiographic diagnosis, treatment and pathologic histology. These cases accumulated over a 33-year period and represent 39% of all of our choroid plexus tumors (n = 28). Characteristically, choroid plexus carcinomas are associated with a poor prognosis for long-term survival. Unfortunately, efforts at total resection are hindered in part by the extreme vascularity of the tumor which itself may be of considerable volume. We have recently treated four children who had biopsy or minimal resection of their tumor after which adjuvant chemotherapy was given. Chemotherapy is not curative but it does cause a reduction in tumor volume and, more importantly, has tended to reduce the tumor vascularity. This allows for a second stage operation which is more safely performed and typically allows for more complete tumor removal. At this point, our length of follow-up is insufficient to conclude if total removal in this manner significantly increases survival but it would seem that consistent gross total removal may be an initial step toward better overall management and prognosis in this tumor type.

Bilateral MRI-Guided Stereotactic Cingulotomy for Intr actable Pain

As a treatment of patients with intractable cancer and noncancer pain, bilateral radiofrequency cingulotomy was performed in 10 patients. The technique involved stereotaxis using magnetic resonance guidance and local anesthesia, with the placement of a radiofrequency lesion (75 degrees, 60s). Of the 10 patients, 8 had metastatic lesions with musculoskeletal (6) or neurogenic (2) pain. Pain relief was judged excellent (4 patients), fair (1), poor (2) and excellent for 6 months poor in the last patient. The two benign lesions were neurofibromatosis with neurogenic pain and thalamic pain from an old stroke. Pain relief (with 1 year follow-up) in this group was judged excellent in one and poor in the other (thalamic pain).

Surgical Management Of Syringomyelia: A Five Year Experience In The Era Of Magnetic Resonance Imaging*

We summarize our experience with 59 consecutive surgically managed cases of syringomyelia (SM) over a 5 year period. All cases had magnetic resonance imaging (MRI) preoperatively and postoperatively. Twenty-eight patients presented with SM and the adult Chiari (Chiari I) malformation (SM-ACM), 6 patients had post traumatic syrinxes, 14 patients had syrinxes associated with an intramedullary neoplasm, 3 patients had syringomyelia associated with spinal arachnoiditis and 8 patients had idiopathic syringomyelia. Holocord syrinxes were more often associated with SM-ACM, while focal syrinxes were associated with posttraumatic, spinal arachnoiditis and neoplastic conditions. In all cases with neoplasms the MRI revealed parenchymal intramedullary signal abnormalities in addition to the syrinx cavity. Posterior fossa decompression with obex plugging (the Gardner operation) was the procedure of choice for SM-ACM and for idiopathic holocord syringomyelia. Exploration and drainage of the syrinx with or without shunting was carried out mainly for focal syrinxes associated with trauma and neoplasm. Patients with SM-ACM responded well to posterior fossa decompression with satisfactory results in 24/28 patients. Idiopathic SM is probably a forme fruste of SM-ACM and when treated with the Gardner procedure showed good results in all 8 patients. Posttraumatic and neoplastic SM had the least predictable results with surgery. The disappearance of the syrinx on postoperative MRI correlated well with a good surgical outcome.

Trigeminal cisternal injection of glycerol for treatment of chronic intractable cluster headaches.

Medical treatment of chronic cluster headaches (cluster headaches that occur frequently without remission) can be very difficult. In many patients, the pain remains severe despite all medication trials. For these patients, previous reports recommend radiofrequency trigeminal rhizotomy, which risks corneal anesthesia and subsequent corneal decompensation. As a safer, yet effective, treatment, retro-Gasserian injections of glycerol were given to eight patients having intractable chronic cluster headaches. Needle penetration into the trigeminal cistern, glycerol amount (0.55 ml), and length of patient elevation after the procedure (80-90 degrees upright for 10 h) were modified for maximal exposure of the V1 division. Three patients required one additional injection, and one patient required two additional injections. Verbal pain scales (means +/- 1 standard error of the mean) were: 9.1 +/- 0.30 (preoperative), 2.6 +/- 1.10 (1 mo postoperative), and 2.1 +/- 0.64 (1 yr postoperative). Daily headache frequency decreased from 6.0 +/- 2.0 (preoperative) to 0.2 +/- 0.09 (i.e., one headache every 5 days) (1 yr postoperative). Three of the eight patients had no headaches after 1 year. There were no instances of corneal or facial anesthesia. One year postoperatively, five patients required no medication, and three remained on low doses of medication for headache treatment. In contrast to previous limited reports of glycerol injections for cluster headaches, results with these patients having chronic cluster headaches support the use of glycerol injections as a viable treatment alternative, with significant pain relief and corneal safety.