✓ A method is described for determining stereotaxic coordinates using computerized tomographic scanning and intraoperative ventriculography of the third ventricle.
Kim J. Burchiel, George A. Ojemann and Nicole Bolender
Case report and review of the literature
Konstantin V. Slavin, Thomas K. Baumann and Kim J. Burchiel
Hemiballismus is a relatively rare movement disorder that is characterized by uncontrolled, random, large-amplitude movements of the limbs. It is usually caused by a vascular lesion that involves the contralateral subthalamic nucleus (STN) (also known as the nucleus hypothalamicus or corpus luysi) and its afferent and efferent pathways.
The authors present a case of medically intractable hemiballismus in a 70-year-old woman who was successfully treated with stereotactic posteroventral pallidotomy. In agreement with the data reported earlier by other groups, the microrecording performed during the pallidotomy showed a decreased rate of firing of the pallidal neurons, supporting the theory of impaired excitatory input from the STN to the internal part of the globus pallidus.
Stereotactic pallidotomy may be the procedure of choice in the treatment of medically intractable hemiballismus. Intraoperative microrecording significantly improves the precision of the stereotactic targeting and should be considered a standard part of the pallidotomy protocol.
Daniel C. Rohrer, Kim J. Burchiel and David P. Gruber
✓ A diverse collection of unverified theories as to the etiology of extradural meningeal cysts have been previously proposed. One case of intraspinal extradural meningeal cyst of the thoracolumbar region is presented in which a ball-valve mechanism involving an idiopathic dural rent and a herniated segment of an underlying dorsal rootlet was suggested by the operative findings. Closure of the dural rent with marsupialization of the meningeal cyst obliterated this extradural lesion. The ball-valve mechanism of formation and other previously proposed theories are discussed.
Andrew L. Ko, Alp Ozpinar, Albert Lee, Ahmed M. Raslan, Shirley McCartney and Kim J. Burchiel
Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). While microvascular decompression (MVD) is the most effective treatment for TN, it is not possible when NVC is not present. Therefore, the authors sought to evaluate the safety, efficacy, and durability of internal neurolysis (IN), or “nerve combing,” as a treatment for TN without NVC.
This was a retrospective review of all cases of Type 1 TN involving all patients 18 years of age or older who underwent evaluation (and surgery when appropriate) at Oregon Health & Science University between July 2006 and February 2013. Chart reviews and telephone interviews were conducted to assess patient outcomes. Pain intensity was evaluated with the Barrow Neurological Institute (BNI) Pain Intensity scale, and the Brief Pain Inventory–Facial (BPI-Facial) was used to assess general and face-specific activity. Pain-free survival and durability of successful pain relief (BNI pain scores of 1 or 2) were statistically evaluated with Kaplan-Meier analysis. Prognostic factors were identified and analyzed using Cox proportional hazards regression.
A total of 177 patients with Type 1 TN were identified. A subgroup of 27 was found to have no NVC on high-resolution MRI/MR angiography or at surgery. These patients were significantly younger than patients with classic Type 1 TN. Long-term follow-up was available for 26 of 27 patients, and 23 responded to the telephone survey. The median follow-up duration was 43.4 months. Immediate postoperative results were comparable to MVD, with 85% of patients pain free and 96% of patients with successful pain relief. At 1 year and 5 years, the rate of pain-free survival was 58% and 47%, respectively. Successful pain relief at those intervals was maintained in 77% and 72% of patients. Almost all patients experienced some degree of numbness or hypesthesia (96%), but in patients with successful pain relief, this numbness did not significantly impact their quality of life. There was 1 patient with a CSF leak and 1 patient with anesthesia dolorosa. Previous treatment for TN was identified as a poor prognostic factor for successful outcome.
This is the first report of IN with meaningful outcomes data. This study demonstrated that IN is a safe, effective, and durable treatment for TN in the absence of NVC. Pain-free outcomes with IN appeared to be more durable than radiofrequency gangliolysis, and IN appears to be more effective than stereotactic radiosurgery, 2 alternatives to posterior fossa exploration in cases of TN without NVC. Given the younger age distribution of patients in this group, consideration should be given to performing IN as an initial treatment. Accrual of further outcomes data is warranted.
Andrew L. Ko, Albert Lee, Ahmed M. Raslan, Alp Ozpinar, Shirley McCartney and Kim J. Burchiel
Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). To characterize what may be distinct patient populations, the authors examined age at onset in patients with TN with and without NVC.
A retrospective review of patients undergoing posterior fossa surgery for Type I TN at Oregon Health & Science University from 2009 to 2013 was undertaken. Charts were reviewed, and imaging and operative data were collected for patients with and without NVC. Mean, median, and the empirical cumulative distribution of onset age were determined. Statistical analysis was performed using Student t-test, Wilcoxon and Kolmogorov-Smirnoff tests, and Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model.
The charts of 219 patients with TN were reviewed. There were 156 patients who underwent posterior fossa exploration and microvascular decompression or internal neurolysis: 129 patients with NVC and 27 without NVC. Mean age at symptoms onset for patients with and without NVC was 51.1 and 42.6 years, respectively. This difference (8.4 years) was significant (t-test: p = 0.007), with sufficient power to detect an effect size of 8.2 years. Median age between groups with and without NVC was 53.25 and 41.2 years, respectively (p = 0.003). Histogram analysis revealed a bimodal age at onset in patients without NVC, and cumulative distribution of age at onset revealed an earlier presentation of symptoms (p = 0.003) in patients without NVC. Chi-square analysis revealed a trend toward female predominance in patients without NVC, which was not significant (p = 0.08). Multivariate analysis revealed that age at onset was related to NVC but not sex, symptom side or distribution, or patient response to medical treatment.
NVC is neither sufficient nor necessary for the development of TN. Patients with TN without NVC may represent a distinct population of younger, predominantly female patients. Further research into the pathophysiology underlying this debilitating disease is needed.
Katherine G. Holste, Frances A. Hardaway, Ahmed M. Raslan and Kim J. Burchiel
Nervus intermedius neuralgia (NIN) or geniculate neuralgia is a rare facial pain condition consisting of sharp, lancinating pain deep in the ear and can occur alongside trigeminal neuralgia (TN). Studies on the clinical presentation, intraoperative findings, and ultimately postoperative outcomes are extremely limited. The aim of this study was to examine the clinical presentation and surgical findings, and determine pain-free survival after sectioning of the nervus intermedius (NI).
The authors conducted a retrospective chart review and survey of patients who were diagnosed with NIN at one institution and who underwent neurosurgical interventions. Pain-free survival was determined through chart review and phone interviews using a modified facial pain and quality of life questionnaire and represented as Kaplan-Meier curves.
The authors found 15 patients with NIN who underwent microsurgical intervention performed by two surgeons from 2002 to 2016 at a single institution. Fourteen of these patients underwent sectioning of the NI, and 8 of 14 had concomitant TN. Five patients had visible neurovascular compression (NVC) of the NI by the anterior inferior cerebellar artery in most cases where NVC was found. The most common postoperative complaints were dizziness and vertigo, diplopia, ear fullness, tinnitus, and temporary facial nerve palsy. Thirteen of the 14 patients reportedly experienced pain relief immediately after surgery. The mean length of follow-up was 6.41 years (range 8 months to 14.5 years). Overall recurrence of any pain was 42% (6 of 14), and 4 patients (isolated NIN that received NI sectioning alone) reported their pain was the same or worse than before surgery at longest follow-up. The median pain-free survival was 4.82 years ± 14.85 months. The median pain-controlled survival was 6.22 years ± 15.78 months.
In this retrospective review, sectioning of the NI produced no major complications, such as permanent facial weakness or deafness, and was effective for patients when performed in addition to other procedures. After sectioning of the NI, patients experienced 4.8 years pain free and experienced 6.2 years of less pain than before surgery. Alone, sectioning of the NI was not effective. The pathophysiology of NIN is not entirely understood. It appears that neurovascular compression plays only a minor role in the syndrome and there is a high degree of overlap with TN.
Andrew C. Zacest, Stephen T. Magill, Jonathan Miller and Kim J. Burchiel
Trigeminal neuralgia (TN) is a neuropathic pain syndrome that is often associated with neurovascular compression of the trigeminal nerve and may be effectively treated with microvascular decompression (MVD). The authors used high-resolution MR imaging with 3D reconstruction in patients with constant facial pain (Type 2 TN) to determine the presence/absence of neurovascular compression and thus a potential MVD benefit. They retrospectively contacted patients to evaluate outcome.
All patients who reported spontaneous onset of constant facial pain (Type 2 TN), which occurred at least 50% of the time, who had undergone high-resolution 3-T MR imaging with 3D reconstruction were retrospectively selected for this study. Clinical history, facial pain questionnaire data, physical examination findings, and results from 3-T 3D MR imaging reconstruction were recorded for all patients. Intraoperative findings and clinical pain outcome were recorded for all patients who underwent MVD.
Data obtained in 27 patients were assessed. On the basis of history and 3D MR imaging reconstruction findings, 13 patients were selected for MVD (Group A) and 14 underwent conservative treatment (Group B). Typical or suspected artery- or vein-induced neurovascular compression was predicted preoperatively in 100% of Group A patients and in 0% of Group B patients. At the time of MVD, definitive neurovascular compression was confirmed in 11 (84.6%) of 13 Group A patients. Following MVD, facial pain was completely relieved in 3 (23%), improved in 7 (53.8%), and no better in 3 (23%) of 13 Group A patients. A history of episodic (Type 1 TN) pain at any time was reported in 100 and 50% of Group A and Group B patients, respectively. A Type 1 TN pain component was reportedly improved/relieved in all Group A patients, but the Type 2 TN pain component was improved in only 7 (53.8%) of 13 patients. The mean postoperative follow-up duration was 13 months.
High-resolution 3D MR imaging reconstruction in patients with constant facial pain (Type 2 TN) can help determine the presence/absence of neurovascular compression. Surgical selection based on both clinical and radiological criteria has the potential to improve surgical outcome in patients with Type 2 TN who may potentially benefit from MVD. However, even in such selected patients, pain relief is likely to be incomplete.
Diaa Bahgat, Dibyendu K. Ray, Ahmed M. Raslan, Shirley McCartney and Kim J. Burchiel
Trigeminal neuralgia (TN) is a form of facial pain that can be debilitating if left untreated. It typically affects elderly adults and is thought to be related to neurovascular compression. It is uncommon in people younger than 30 years of age, with only 1% of cases reportedly occurring in those younger than 20 years of age. The most common cause of compression in young adults is thought to be venous nerve compression either alone or in association with arterial nerve compression. The objective of this study was to review data in cases of TN in which patients were 25 years of age or younger and to identify TN disease characteristics, demographics, clinical features, operative findings, and outcome.
The authors retrospectively reviewed the clinical records, surgical treatment, and long-term outcome in patients 25 years of age or younger with TN who underwent surgery performed by the senior author (K.J.B.) at Oregon Health & Science University between 1995 and 2008.
Seven patients (2 males and 5 females) met the inclusion criteria. The average age at symptom onset was 19.6 ± 3.4 years (± SD) and the average age at surgery was 22.9 ± 1.7 years. Six patients had right-sided symptoms and 1 had left-sided symptoms. Pain distribution was the V2 in 3 cases, V2–3 in 3 cases, and V3 in 1 case, with no cases of V1 affliction. A total of 11 procedures were performed in 7 patients, and 4 patients underwent a second procedure. Surgery and imaging revealed venous compression in all cases. The average follow-up period was 35.5 ± 39.9 months (median 12 months). Three patients reported a good outcome (no pain with or without medications) and 4 reported a poor outcome (either no pain relief or mild pain relief after surgery).
Trigeminal neuralgia is uncommon in young adults. Patients tend to present with symptoms similar to those in adults: long periods of pain and venous compression, but outcome unfortunately is not as good as that reported in the older population.
Roberto C. Heros
Ahmed M. Raslan, Justin S. Cetas, Shirley McCartney and Kim J. Burchiel
Historically, destructive procedures for cancer pain were the main line of treatment therapy. However, the use of high-dose opioids has essentially replaced such procedures. Recognition of the limits of medical therapy to treat cancer pain effectively is growing, while conversely, in regions with limited access to pain medications, the importance of destructive surgical techniques is increasing. A critical evaluation of the evidence for destructive techniques is warranted, and the authors review current evidence underlying these procedures.
A US National Library of Medicine PubMed search for “ablation,” “DREZ,” “dorsal root entry zone,” “cingulotomy,” “cordotomy,” “ganglionectomy,” “mesencephalotomy,” “myelotomy,” “neurotomy,” “neurectomy,” “rhizotomy,” “sympathectomy,” “thalamotomy,” “tractotomy,” and “pain” was undertaken. The search was then limited to human studies, English-language literature, cancer pain, and reports with more than 1 patient.
One hundred twenty papers were identified and reviewed based on the selection criteria described. According to the Canadian and US task forces, classification of clinical research literature only “sympathectomy” was supported by Class I or II studies, with 2 Class I papers and 1 Class II paper identified for cancer pain. All other procedures were supported by Class III studies of variable quality. Cordotomy in particular was the most extensively studied and reviewed procedure. Given the large number of patients studied, consistent results, multiplicity of reports and, even though evidence quality for individual studies was relatively low, cumulative evidence suggests that cordotomy may play an important role in the treatment of cancer pain.
Destructive procedures for cancer pain may play more than a historic role in the management of cancer pain. Cumulative evidence from even the poorest quality studies suggests that some procedures, such as cordotomy, should be included in the armamentarium available to the neurosurgeon today. To renew appropriate interest in these procedures, evidence and studies that meets today's evidence-based research criteria are warranted.