Tejas Sankar and Andres M. Lozano
Favorable results with syringoperitoneal shunting
Nicholas M. Barbaro, Charles B. Wilson, Philip H. Gutin and Michael S. B. Edwards
✓ The authors reviewed the clinical findings, radiological evaluation, and operative therapy of 39 patients with syringomyelia. Syringoperitoneal (SP) shunting was used in 15 patients and other procedures were used in 24 patients. Follow-up periods ranged from 1½ to 12 years. During the period of this study, metrizamide myelography in conjunction with early and delayed computerized tomography scanning replaced all other diagnostic procedures in patients with syringomyelia. Preoperative accuracy for the two procedures was 87%.
The most common symptoms were weakness (79%), sensory loss (67%), pain (38%), and leg stiffness (28%). Surgery was most effective in stabilizing or alleviating pain (100%), sensory loss (81%), and weakness (74%); spasticity, headache, and bowel or bladder dysfunction were less likely to be reversed. Approximately 80% of patients with idiopathic and posttraumatic syringomyelia and 70% of those with arachnoiditis improved or stabilized. Better results were obtained in patients with less severe neurological deficits, suggesting the need for early operative intervention. A higher percentage of patients had neurological improvement with SP shunting than with any other procedure, especially when SP shunting was the first operation performed. Patients treated with SP shunts also had the highest complication rate, most often shunt malfunction. These results indicate that SP shunting is effective in reversing or arresting neurological deterioration in patients with syringomyelia.
Devin K. Binder, Paul A. Garcia, Ganesh K. Elangovan and Nicholas M. Barbaro
Prior studies suggest that aura semiology may have localizing value. However, temporal lobe aura characteristics and response to surgery have not been studied in large patient series.
The authors retrospectively analyzed the case records of 182 patients undergoing temporal lobectomy for medically intractable epilepsy at a single institution. They analyzed the frequency and type of auras and seizures preoperatively, and at 3 months and 1 year after temporal lobectomy. Auras were divided into medial semiology (rising epigastric, olfactory/gustatory, experiential, and fear) and lateral semiology (auditory, somatosensory, and visual), or other.
Of 182 patients, 150 were included in this study. The preoperative prevalence of auras was 77%. Multiple types of auras were present in 20% of patients. The most common aura was rising epigastric (26% of all auras). Postoperatively, auras were eliminated in 63% of patients at 3 months and in 64% at 1 year. Seventy-seven patients (51%) were seizure-free and aura-free, 22 (15%) were seizure-free with auras, 26 (17%) had seizures but no auras, and 25 (17%) had seizures with auras. Despite having their auras eliminated, 6.7% of patients continued to have complex partial seizures. Lateral temporal auras were more than twice as likely as medial temporal auras to persist after surgery (p < 0.002).
While the majority of patients in the authors' series became seizure- and aura-free, a significant minority still had persistent auras. Patients with lateral temporal auras appear to be at increased risk for having persistent postoperative auras. The discrepancy between aura and seizure outcomes results in a small group of patients having persistent seizures but losing their auras postoperatively.
Philip A. Starr, Nicholas M. Barbaro, Neil H. Raskin and Jill L. Ostrem
Cluster headache (CH) is the most severe of the primary headache disorders. Based on the finding that regional cerebral blood flow is increased in the ipsilateral posterior hypothalamic region during a CH attack, a novel neurosurgical procedure for CH was recently introduced: hypothalamic deep brain stimulation (DBS). Two small case series have been described. Here, the authors report their technical approach, intraoperative physiological observations, and 1-year outcomes after hypothalamic DBS in four patients with medically intractable CHs.
Patients underwent unilateral magnetic resonance (MR) imaging–guided stereotactic implantation of a Medtronic DBS (model 3387) lead and Soletra pulse generator system. Intended tip coordinates were 3 mm posterior, 5 mm inferior, and 2 mm lateral to the midcommissural point. Microelectrode recording and intraoperative test stimulation were performed. Lead locations were measured on postoperative MR images. The intensity, frequency, and severity of headaches throughout a 1-week period were tracked in patient diaries immediately prior to surgery and after 1 year of continuous stimulation.
At the 1-year follow-up examination, DBS had produced a greater than 50% reduction in headache intensity or frequency in two of four cases. Active contacts were located 3 to 6 mm posterior to the mammillothalamic tract. Neurons in the target region showed low-frequency tonic discharge.
In two previously published case series, headache relief was obtained in many but not all patients. The results of these open-label studies justify a larger, prospective trial but do not yet justify widespread clinical application of this technique.
Jason S. Cheng, Rene O. Sanchez-Mejia, Mary Limbo, Mariann M. Ward and Nicholas M. Barbaro
Trigeminal neuralgia (TN) is a painful disorder that frequently causes lancinating, electrical shock–like pain in the trigeminal distribution. Common surgical treatments include microvascular decompression (MVD), radio-surgery, and radiofrequency ablation, and complete pain relief is generally achieved with a single treatment in 70 to 85% of cases for all modalities. In a subset of patients with multiple sclerosis (MS), however, the rates of surgical treatment failure and the need for additional procedures are significantly increased compared with those in patients without MS. In this study the authors report their experience with a cohort of 11 patients with TN who also had MS, and assess the efficacy of MVD, gamma knife surgery (GKS), and radiofrequency ablation in achieving complete or partial long-term pain relief.
Eleven patients with TN and MS who were treated by the senior author (N.B.) at the University of California, San Francisco were included in this study. All patients underwent GKS and/or radiofrequency ablation, and four received MVD. A detailed clinical history and intraoperative findings were recorded for each patient and frequent follow-up evaluations were performed, with a mean follow-up duration of 40.6 months (range 1–96 months). Pain was assessed for each patient by using the Barrow Neurological Institute scale (Scores I–V).
Achieving complete pain relief in patients with TN and MS required significantly more treatments compared with all other patients with TN who did not have MS (p = 0.004). Even when compared with a group of 32 patients who had highly refractory TN, the cohort with MS required significantly more treatments (p = 0.05). Radiosurgery proved to be an effective procedure and resulted in fewer retreatments and longer pain-free intervals compared with MVD or radiofrequency ablation.
Dario J. Englot, Mitchel S. Berger, Nicholas M. Barbaro and Edward F. Chang
Seizures are the most frequent presenting symptom in patients with low-grade gliomas (LGGs), and significantly influence quality of life if they are uncontrolled. Achieving freedom from seizures is of utmost importance in surgical planning, but the factors associated with seizure control remain incompletely understood.
The authors performed a systematic literature review of seizure outcomes after resection of LGGs causing seizures, examining 773 patients across 20 published series. Rates of seizure freedom were stratified across 7 variables: patient age, tumor location, preoperative seizure control with medication, seizure semiology, epilepsy duration, extent of resection, and the use of intraoperative electrocorticography (ECoG).
Gross-total resection was most predictive of complete seizure freedom, when compared with subtotal resection (OR 3.41, 95% CI 2.36–4.93). Other predictors of seizure freedom included preoperative seizure control on antiepileptic medication (OR 2.12, 95% CI 1.33–3.38) and duration of seizures of ≤ 1 year (OR 1.85, 95% CI 1.22–2.79). Patients with simple partial seizure semiology achieved seizure freedom less often than those with complex partial, generalized, or mixed seizure types (OR 0.46, 95% CI 0.26–0.80). No significant differences in seizure outcome were observed between adults versus children, patients with temporal lobe versus extratemporal tumors, or with the use of intraoperative ECoG.
Seizure control is one of the most important considerations in planning surgery for low-grade brain tumors. Gross-total resection is a critical factor in achieving seizure freedom.
Edward F. Chang, Doris D. Wang, David W. Perry, Nicholas M. Barbaro and Mitchel S. Berger
Language dominance in the right hemisphere is rare. Therefore, the organization of essential language sites in the dominant right hemisphere is unclear, especially compared with cases involving the more prevalent left dominant hemisphere.
The authors reviewed the medical records of 15 patients who underwent awake craniotomy for tumor or epilepsy surgery and speech mapping of right hemisphere perisylvian language areas at the University of California, San Francisco. All patients were determined to have either complete right-sided or bilateral language dominance by preoperative Wada testing.
All patients but one were left-handed. Of more than 331 total stimulation sites, 27 total sites were identified as essential for language function (14 sites for speech arrest/anarthria; 12 for anomia; and 1 for alexia). While significant interindividual variability was observed, the general pattern of language organization was similar to classic descriptions of frontal language production and posterior temporal language integration for the left hemisphere. Speech arrest sites were clustered in the ventral precentral gyrus and pars opercularis. Anomia sites were more widely distributed, but were focused in the posterior superior and middle temporal gyri as well as the inferior parietal gyrus. One alexia site was found over the superior temporal gyrus. Face sensory and motor cortical sites were also identified along the ventral sensorimotor strip. The prevalence and specificity of essential language sites were greater in unilateral right hemisphere–dominant patients, compared with those with bilateral dominance by Wada testing.
The authors' results suggest that the organization of language in right hemisphere dominance mirrors that of left hemisphere dominance. Awake speech mapping is a safe and reliable surgical adjunct in these rare clinical cases and should be done in the setting of right hemisphere dominance to avoid preventable postoperative aphasia.
R. Mark Richardson, Nicholas M. Barbaro, Arturo Alvarez-Buylla and Scott C. Baraban
✓ Mesial temporal lobe epilepsy (MTLE) is presumed to develop progressively as a consequence of synaptic reorganization and neuronal loss, although the exact etiology of seizure development is unknown. Nearly 30% of patients with MTLE have disabling seizures despite pharmacological treatment, and the majority of these patients are recommended for resection. The authors review cell transplantation as an alternative approach to the treatment of epilepsy. Recent work in animal models shows that grafted neuronal precursors that differentiate into inhibitory interneurons can increase the level of local inhibition. Grafts of these inhibitory neurons could help restore equilibrium in MTLE. Developing a sound transplantation strategy involves careful consideration of the etiology of MTLE and the expected functional role of transplanted cells. These issues are reviewed, with a focus on those factors most likely to influence clinically applicable results.