Andrew J. Fabiano

Laser-Interstitial Thermal Therapy for Refractory Cerebral Edema from Post-Radiosurgery Metastasis

BACKGROUND Stereotactic radiosurgery is often an effective tool for the treatment of brain metastases. A complication of radiosurgical treatment for brain metastasis can be persistent cerebral edema. Treatments of this refractory cerebral edema include observation, corticosteroids, and surgical resection of the edema-inducing mass. Laser-interstitial thermal therapy is a minimally invasive technique for ablating intracranial lesions. It may provide a treatment option for metastases after radiosurgery causing refractory cerebral edema. CASE DESCRIPTION We report the case of a 64-year-old man with lung adenocarcinoma presenting to our department with left hemiparesis. Brain magnetic resonance imaging showed an 18-mm enhancing lesion in the right external capsule with significant surrounding edema. The lesion was treated by radiosurgery. There was persistent edema after radiosurgery. The patient required continued corticosteroid therapy to maintain his ability to ambulate. He developed refractory hyperglycemia, weight gain, and bilateral proximal muscle weakness secondary to this therapy. Fourteen weeks after radiosurgery, he underwent laser-interstitial thermal therapy for lesion ablation. He was weaned off corticosteroids during 2 weeks and maintained his strength during the following month. CONCLUSIONS Laser-interstitial thermal therapy may be a treatment option for refractory cerebral edema after stereotactic radiosurgery to a metastasis. This therapy may be of particular use in deep-seated lesions refractory to corticosteroid therapy.

Delayed stoma failure in adult communicating hydrocephalus after initial successful treatment by endoscopic third ventriculostomy: case report.

OBJECTIVETo describe 2 cases of delayed endoscopic third ventriculostomy (ETV) failure in 2 adult patients initially successfully treated for normal pressure hydrocephalus by ETV. The cause of ETV failure was stoma closure, and this was documented in both instances by direct endoscopic inspection. CLINICAL PRESENTATIONIn the first case, a 67-year-old woman presented with progressive gait disturbance, incontinence, and memory problems. Brain magnetic resonance imaging exhibited ventricular dilation, including the fourth ventricle, disproportionate to cortical atrophy. In the second case, a 55-year-old man presented with progressive gait disturbance, urinary incontinence, memory problems, and headaches. Brain magnetic resonance imaging exhibited communicating hydrocephalus. INTERVENTIONThe first patient underwent an ETV with subsequent improvement in all symptom areas. Three years and 2 months later, she experienced a return of original symptoms and ventricular dilation on brain computed tomography, compared with previous postoperative scans. Direct endoscopic inspection of the third ventricular floor revealed stoma closure secondary to fibrotic scar. The patient subsequently underwent ventriculoperitoneal shunt placement that resulted in symptom improvement. The patient in the second case underwent an ETV that resulted in marked symptom improvement in all areas. Four years and 3 months later, he experienced a return of gait difficulties and headaches. Direct endoscopic inspection showed a lack of cerebrospinal fluid pulsations through the third ventricular stoma and dense arachnoid adhesions around the basilar artery. A repeat ETV was unsuccessful. Subsequent ventriculoperitoneal shunt placement resulted in symptom improvement. CONCLUSIONETV may provide an effective treatment for patients with normal pressure hydrocephalus, a form of communicating hydrocephalus. Stoma closure can be a mechanism of delayed ETV failure in normal pressure hydrocephalus, consistent with reports of ETV failure in pediatric obstructive hydrocephalus.

Posterior cerebral artery P1 segment at the stoma during endoscopic third ventriculostomy in adults

Objectives A serious catastrophic complication of endoscopic third ventriculostomy (ETV) is basilar artery (BA) damage. Although the BA has been discussed as the cause of haemorrhage and even pseudoaneurysm, variations of the posterior cerebral artery proximal segment (P1) and its protrusion into the third ventricle floor have not been emphasised. A series of cases are reported in which the P1 segment was located at the stoma during an ETV and was at risk of perforation. Precautionary techniques for complication avoidance are described. Methods A retrospective review was performed of all ETVs performed in adults at our institution between 2004 and 2008. Cases were identified in which the P1 segment was noted to herniate into the stoma at the time of third ventricular floor fenestration. Results Among 65 cases reviewed, six were identified in which the P1 segment significantly herniated into an area of the stoma at the time of third ventricular floor fenestration. In no case was the P1 segment injured by the ETV procedure. Each of the six patients had opaque third ventricle floors. A ‘cookie cut’ technique was used in which the opaque third ventricle floor was abraded to reveal the underlying translucent membrane, offering an improved view of arteries in the basilar cisterns. In four of six patients, ETV resulted in clinical improvement. Conclusions The posterior cerebral artery P1 segment is potentially at risk during ETV in adults as well as in children. Awareness and proper precautions may help reduce injuries to either the P1 or the basilar apex during an ETV.

Tumoral Bing-Neel Syndrome presenting as a cerebellar mass

Waldenstrom’s macroglobulinemia (WM) is a low-grade alignant monoclonal proliferation of immunoglobulin M (IgM)roducing lymphocytes capable of exhibiting plasmacytoid or lasma cell differentiation [1]. According to the World Health Orgaization’s classification of neoplastic diseases of hematopoietic and ymphoid tissues, WM is classified as lymphoplasmacytic lymhoma. Clinical features of WM may include cytopenia, bleeding, ymphadenopathy, splenomegaly, and, most commonly, a hyperiscosity syndrome related to high serum levels of monoclonal IgM. entral nervous system (CNS) complications arise in approximately 5% of WM cases, usually as a result of the hyperviscosity syndrome r an immune-related neuropathy [1,2]. Rare cases of WM involvng direct CNS infiltration by malignant cells have been referred to s Bing-Neel Syndrome (BNS). To date, limited data exist regardng BNS. The authors describe a rare case of BNS presenting as a erebellar mass with associated brainstem infiltration and subacute eurologic deterioration.

Intracranial meningiomas in patients with uterine sarcoma treated with long-term megestrol acetate therapy.

OBJECTIVE To report a series of four patients with uterine sarcoma, including one with müllerian adenosarcoma (MA) and three with low-grade endometrial stromal sarcoma (LGESS), who developed intracranial meningiomas while receiving the progesterone agonist megestrol acetate. METHODS The hospital records, imaging studies, and pathology slides of four patients who were treated for uterine sarcomas and subsequently developed intracranial meningiomas were reviewed. RESULTS All patients underwent surgery for their gynecologic cancers and received maintenance therapy with long-term hormonal suppression with megestrol acetate. Each of the four patients later developed neurologic symptoms secondary to intracranial meningiomas. Three patients had more than one meningioma. Histopathologic examination of all excised tumors showed strong immunoreactivity for progesterone receptors (PRs). CONCLUSIONS Patients with uterine sarcoma subtypes LGESS and MA may be predisposed to develop meningiomas, particularly in the setting of long-term treatment with megestrol acetate. Alternatively, preexisting, clinically silent meningiomas in these patients may have progressed to the point of clinical symptoms in the presence of the progesterone agonist megestrol acetate. Without previous imaging studies showing the presence or absence of meningioma before initiation of megestrol acetate treatment, there is no way to draw definitive conclusions regarding this possibility. Clinical and neuroradiologic surveillance for meningiomas should be strongly considered in patients with these uterine sarcoma subtypes, particularly in patients undergoing long-term suppressive therapy with megestrol acetate.

Distal Baclofen Pump Catheter Migration Associated with Far‐Lateral Paraspinal Surgical Placement

Objectives.  The increased rigidity and spasms implicit to patients being treated with baclofen provide a potential source of drug delivery system–related complications. Placement of the intrathecal catheter from the far‐lateral paraspinal approach has been advocated to avoid catheter fracture as previously reported with a midline approach. A thin fascial layer and increased muscle bulk laterally could increase motion of catheters placed in this position. The authors report on a series of patients found to have spinal catheter migration out from the thecal sac following a far‐lateral paraspinal surgical approach.

Intrathecal Medications in Post‐Herpetic Neuralgia

Dear Editor: We write to report on a series of patients with medication-refractory post-herpetic neuralgia (PHN) treated by continuous intrathecal opioid administration. PHN is the persistence of pain for more than 1 month following the onset of a herpes zoster rash (1). This condition occurs in 15% of patients with shingles and may last for years (2). It is a notoriously difficult to treat, and multiple medications from a variety of medication classes have been used. Oral and transdermal opioids are used for treatment but are often overly sedating, particularly in the geriatric population. Intrathecal opioid administration has successfully treated certain chronic pain conditions (3). Drug delivery directly to the central nervous system allows for smaller opioid doses and less systemic side effects and may provide a useful therapy for PHN. A retrospective review was performed of the clinical records of five consecutive patients treated at Buffalo General Hospital for medication-refractory PHN by surgical implantation of a pump–catheter drug-delivery system (SynchroMed I, Medtronic, Inc., Minneapolis, MN, USA) for intrathecal opioid administration. The initial opioid agent administered was morphine, with sufentanyl used for those patients experiencing a morphine side-effect. Doses of the primary opioid were escalated; and, if the patient’s pain was still not controlled, a second agent was added. Medication selection and management were performed in accordance with current consensus guidelines (4). All patients were treated for PHN by intrathecal opioid administration over an 11-year period between May 1997 and August 2008. Each patient had clinically diagnosed herpes zoster. Average patient age at the time of pump placement was 73 years; two patients were women. The average duration of clinical follow-up was 5.8 years (range 2.0–8.3 years). Conventional medical therapy was a failure in all patients due to inadequate pain control or intolerable medication side-effects. Failed conventional therapies included oral morphine, hydrocodone, and tramadol, transdermal fentanyl, epidural steroid injections, and transcutaneous electrical nerve stimulation. Four patients had pain rated 10/10 on a 10-point pain scale (0=no pain; 10=excruciating pain) while taking conventional oral and transdermal pain medications. The fifth patient’s pain was controlled with oral morphine and hydrocodone and transdermal fentanyl, but this patient slept for 18 hours each day while on this pain management regimen. Before pump implantation, two patients underwent an intrathecal morphine trial, two patients underwent an epidural morphine trial, and one patient (with a history of morphine intolerance) underwent an epidural sufentanyl trial. In each case, the patient’s pain improved significantly during the trial. Trials were considered successful if patients had more than 50% reduction in pain score on the visual analog scale and an improved ability to sleep and/or perform activities as a result of pain reduction. This method of trial and the use of both intrathecal and epidural injections is in concordance with the methods described in the prospective, randomized trial by Anderson et al. (5) for the selection of patients for continuous intrathecal opioid infusion. Following pump implantation and intrathecal drug delivery, all patients had more than 50% improvement in the pain score as measured by the Visual Analog Scale (6). Patient pain improved by an average of 6.8 points on the 10-point pain scale. There were no complications related to the pump or catheter drug-delivery systems. Patients were assessed by a neurosurgeon (RJP) regularly, and the time between appointments ranged from 1 to 12 weeks. Each patient’s pain remained controlled by intrathecal medications, without intolerable side effects for the entire follow-up period. Medication tolerance occurred; however, 4 of 5 patients required escalating medication doses and/or additional medications to achieve long-term pain control. The medications used were morphine alone; sufentanyl alone; morphine and bupivacaine; sufentanyl and bupivacaine; and sufentanyl, bupivacaine, and clonidine (Table 1). Table 1 Demographics for Consecutive Series of Patients Receiving Intrathecal Opioids for Post-herpetic Neuralgia Neuropathic pain is difficult to treat, and its response to oral or transdermal opioids is variable. Large opioid doses are often required to control neuropathic pain. In the present study, even on large doses of oral and/or transdermal opioids, four of five patients still reported 10/10 pain, with the fifth patient over-sedated by the amount of opioid medication required to control his symptoms. Intrathecal opioid administration allows for direct drug delivery to the central nervous system, with minimal systemic side effects. In all five patients in the study, the neuropathic pain was well-controlled, without any significant systemic side effects. The difficulty in controlling the pain of PHN has previously led to the treatment of this condition with invasive methods. Spinal alcohol neurolysis and sympathetic blocks have been performed with some success (7). PHN has been treated previously by intrathecal medication administration. Intrathecal methylprednisolone has been given in bolus form and resulted in an improvement in neuropathic pain (8). However, the utility of this treatment has been questioned because of the associated complications, including meningitis, arachnoiditis, and cauda equine syndrome (9). A case has been reported in which baclofen was delivered continuously to the intrathecal space and was successful at controlling PHN (10). Continuous drug administration was accomplished by a pump–catheter system, as was used in the present study. This method of drug delivery has a relatively low complication rate when used for other chronic pain conditions (3). Herpes zoster and PHN are relatively common conditions. As the population ages and patients with acquired immunodeficiency syndrome live longer with their disease, the prevalence of PHN in the United States likely will increase. Even with more aggressive use of antiviral therapy, there is still likely to be a large group of patients with PHN (11). The Varicella zoster virus vaccine is a live attenuated vaccine and, although it may reduce the risk of PHN, it is not protective against this condition, particularly in the immunocompromised (12). The symptoms of PHN can be debilitating, severe, and chronic. Continuous intrathecal opioid administration may provide a treatment alternative in a select group of patients with refractory PHN. We recommend an intrathecal or epidural opioid trial prior to pump implantation, as was performed during this case series. PHN is a chronic pain condition that can be difficult to treat. Patients with PHN refractory to medical management may benefit from intrathecal opioid administration. Further study is warranted, including a blinded, randomized-controlled trial, in order to make more definitive conclusions.

Diagnosis of facial nerve schwannoma by magnetic resonance imaging enhancement of the geniculate ganglion.

diagnosis of facial nerve schwannoma was based on this enhancement pattern. The patient had a retromastoid craniotomy and intentional subtotal tumor resection. Intraoperatively, the normal-appearing portion of the right facial nerve was identified and noted to be contiguous with the tumor. The pathologicdiagnosiswasschwannoma.No operative complications occurred. Ten months postoperatively, the patient had radiosurgery of the residual tumor. One year after radiosurgery, the patient had full facial sensation, no eye dryness, and mild facial asymmetry. Follow-up imaging showed that the residual tumor had decreased in size (Figure 2), and the patient has returned to work. COMMENT

Bevacizumab for the treatment of post-stereotactic radiosurgery adverse radiation effect.

Background: Adverse radiation effect (ARE) is one of the complications of stereotactic radiosurgery. Its treatment with conventional medications, such as corticosteroids, vitamin E, and pentoxifylline carries a high risk of failure, with up to 20% of lesions refractory to such medications. In addition, deep lesions and those occurring in patients with significant medical comorbidities may not be suitable for surgical resection. Bevacizumab is an antiangiogenic monoclonal antibody against vascular endothelial growth factor, a known mediator of cerebral edema. It can be used to successfully treat ARE. Case Description: An 85-year-old man with a history of small-cell lung cancer presented with metastatic disease to the brain. He underwent stereotactic radiosurgery to a brain metastasis involving the right external capsule. Three months later, the lesion had increased in size, with significant surrounding edema. The patient developed an adverse reaction to steroid treatment and had a poor response to treatment with pentoxifylline and vitamin E. He was deemed a poor surgical candidate because of his medical comorbidities. He was eventually treated with 3 doses of bevacizumab, and the treatment resulted in significant clinical improvement. Magnetic resonance imaging showed some decrease in the size of the lesion and significant decrease in the surrounding edema. Conclusions: Bevacizumab can be successfully used to treat ARE induced by stereotactic radiosurgery in patients with cerebral metastases. It is of particular benefit in patients considered unsuitable for surgical decompression. It is also beneficial in patients with poor tolerance to corticosteroids and in patients who do not respond to other medications.

Approach for tunneling the lead in deep brain stimulation

The implantation of a deep brain stimulator (DBS) is often a staged procedure that involves stereotactic placement of the neurostimulator electrode, followed by connection of the electrode to a pulse generator during a separate operation. The authors describe a practical technique for the retrograde tunneling of the stimulator lead during the initial electrode implantation procedure. After DBS electrode placement and securing of the lead, the lead is covered with a protective cap and boot, which are then folded back to tunnel a redundant loop of the lead in a retrograde fashion into a subgaleal pocket. This technique facilitates connection of the lead to the pulse generator connecting wire at the subsequent operation and may reduce lead damage.