Jan Regelsberger

Reduced Perception of Dyspnea and Pain after Right Insular Cortex Lesions

RATIONALE The perception of dyspnea and pain show many similarities. Initial imaging studies suggested an important role of the insular cortex for the perception of both sensations. However, little is known about the cortical processing of dyspnea. OBJECTIVES This study investigated the influence of lesions of the insular cortex on the perception of dyspnea and pain. METHODS Dyspnea was induced by resistive loaded breathing in four patients with right-hemispheric insular cortex lesions, as assessed with computer tomography or magnetic resonance imaging, and four matched healthy control subjects. Pain was induced by a cold-pressor test. Perceived intensity and unpleasantness of both sensations were rated on visual analog scales. MEASUREMENTS AND MAIN RESULTS In contrast to healthy control subjects, patients with lesions demonstrated reduced perceptual sensitivity for dyspnea, in particular for the unpleasantness of dyspnea (P < 0.05). This was paralleled by reduced sensitivity for pain in patients with lesions, as reflected by smaller ratings of intensity and unpleasantness, higher sensory pain-thresholds, and, in particular, higher affect-related pain tolerance times (P < 0.05). CONCLUSIONS The results suggest that lesions of the right insular cortex are associated with reduced sensitivity for the perception of dyspnea and pain, in particular for their perceived unpleasantness. This underlines the importance of the insular cortex for the perception of both sensations.

Territorial and Microvascular Perfusion Impairment in Brain Arteriovenous Malformations

BACKGROUND AND PURPOSE: Both the existence and clinical relevance of a steal phenomenon in brain arteriovenous malformations (AVMs) remains a matter of debate. This study aimed to assess perfusion in the brain adjacent to brain AVMs and to relate these to macrovascular blood flow in a single measurement. MATERIALS AND METHODS: Twenty consecutive patients with AVMs with a median age of 37 years were evaluated by 3T MR imaging by using 3D time-resolved MR angiography to determine blood flow and perfusion patterns. Cerebral perfusion was estimated by using an arterial spin-labeling technique in vascular territories around the nidus and in symmetric regions of interest in the ipsilateral and contralateral hemispheres. Mapping of concentric shells around the nidus was used to define the immediate and adjacent brain and relative perfusion reductions >20% of baseline, termed perinidal dip (PND). RESULTS: A significant reduction in perfusion ratios between ipsilateral and contralateral hemispheres remote to the AVMs was demonstrated in the middle and posterior cerebral artery territories. PND was detected in 5 patients, and 17 patients overall showed reduced perfusion in the perinidal region on visual inspection. There was a negative correlation of the hemispheric territorial perfusion with the affected/nonaffected inflow time ratio (R = −0.402, P = .015). CONCLUSIONS: The perfusion impairment in vascular territories adjacent to brain AVMs that we identified as PND may reflect the existence of 2 levels of perfusion impairment: a territorial and a microvascular perfusion disturbance. Although the hemispheric asymmetry in territorial perfusion seems the result of arterioarterial redistribution, the PND was inhomogeneously distributed within a single vascular territory and thus might result from low perfusion pressure in small arteries and arterioles.

Secretory meningiomas: a benign subgroup causing life-threatening complications.

While meningiomas are known as slow-growing extracerebral neoplasms, the subgroup of secretory meningiomas with histologically benign characteristics tend to cause disproportional peritumoral edema, frequently leading to severe medical and neurological complications in postoperative management. Among 1,484 meningiomas that were resected at our institution between 1990 and 2007, 44 (3%) patients were found to have the histological diagnosis of a secretory meningioma. The clinical course, radiological appearance, and histopathological features were retrospectively analyzed to examine the specifics of these benign lesions. Meningiomas were located at the convexity (n = 14), the cranial base (18), and the sphenoid ridge (12). A severe, nearly hemispheric perifocal edema disproportional to tumor size was seen on preoperative MR imaging in 18 (41%) patients. Following surgical resection, the postoperative course was uneventful in 29 patients. In 15 patients, severe peritumoral edema continued or even increased on postoperative CT imaging. Six patients showed midline shift and clinical worsening necessitating respirator-assisted ventilation and intracranial pressure monitoring. An association between the extent of brain edema and number of periodic acid Schiff-positive pseudopsammomas was found (p < 0.02). Further, the size of the edema correlated with the number of immunohistochemically detected cells expressing carcinoembryonic antigen (CEA) and cytokeratin (CK) (p < 0.01). Mean MIB-1 (Ki-67 antigen) proliferation index was 3.0% (range, 0%-17%) and did not correlate with edema or tumor recurrence. Secretory meningiomas are frequently associated with severe peritumoral edema. The extent of edema correlates with immunohistochemically detected expression of CEA and CK. Extended perifocal edema in meningiomas is an unusual finding and should alert the neurosurgeon that surgery may aggravate edema excessively, leading to a life-threatening postoperative situation.

Blister-like aneurysms--a diagnostic and therapeutic challenge.

Blister-like internal carotid artery (ICA) aneurysms are known for their fragile and thin-walled morphology associated with a high risk of intraprocedural rupture. Neurosurgical and endovascular options are illustrated on three exemplary cases reviewing the diagnostic and therapeutic implications of these special aneurysms. A 49-year-old woman was admitted with subarachnoid hemorrhage (SAH) in which angiography showed a broad-based, small bulging ectasy of the terminal ICA segment. On the attempt of surgical clipping, the aneurysm ruptured leaving a tear in the ICA. After temporary clipping, the rims of the tear were approximated by sutures. Sufficient closure of the remaining leakage was achieved by circumferential wrapping which was secured by two clips. Postoperative angiography confirmed stenosis of the tightened ICA and patient recovered without neurological deficit. Surgical attempt on a second case with bulging of the C4-segment topped by a small aneurysm was fatal due to extensive laceration of the basal ICA intraoperatively. Endovascular stenting was the choice of treatment in a third SAH patient in which angiography was suspicious of a blister-like ICA aneurysm. Six-month follow-up was uneventful; the patient recovered well and further growth of bulging was not seen. Reviewing the literature, blister-like aneurysms tend to arise at uncommon sites not located at the arterial branches. Small and broad-based bulges with or without true saccular aneurysms have to be assessed as characteristic features of blister-like aneurysms. Rupture of the aneurysm involving the carrying artery has to be considered during therapeutic attempts, in which urgent strategies have to be kept in reserve preventing fatal outcome. Blister-like aneurysms is a hazardous affair for neurosurgeons and neuroradiologists as their fragile structure most likely will lead to intraoperative rupture. If endovascular treatment is not promising, wrapping and revascularization techniques come true to still be an important part of the neurosurgeons toolbox for reconstructing a vessel lumen and preserving a sufficient cerebral blood flow.

Persistent Hemodynamic Changes in Ruptured Brain Arteriovenous Malformations

Background and Purpose— Hemodynamic properties of brain arteriovenous malformations (AVMs) with risk factors for a future hemorrhage are essentially unknown. We hypothesized that AVMs with anatomic properties, which are associated with an increased rupture risk, exhibit different hemodynamic characteristics than those without these properties. Methods— Seventy-two consecutive patients with AVMs diagnosed by conventional angiography underwent MRI examination, including time-resolved 3-dimensional MR angiography. Signal-intensity curves derived from the time-resolved 3-dimensional MR angiography datasets were used to calculate relative blood flow transit times through the AVM nidus based on the time-to-peak parameter. For identification of characteristics associated with altered transit times, a multiple normal regression model was fitted with stepwise selection of the following regressors: intracranial hemorrhage, deep nidus location, infratentorial location, deep drainage, associated aneurysm, nidus size, draining venous stenosis, and number of draining veins. Results— A previous intracranial hemorrhage is the only characteristic that was associated with a significant alteration of the relative transit time, leading to an increase of 2.4 seconds (95% CI, 1.2–3.6 seconds;, P<0.001) without adjustment and 2.1 seconds (95% CI, 0.6–3.6 seconds; P=0.007) with adjustment for all other regressors considered. The association was independent of the bleeding age. Conclusion— Hemodynamic parameters do not seem useful for risk assessment of an AVM-related hemorrhage because only a previous AVM rupture leads to a significant and permanent alteration of the hemodynamic situation.

Dynamics of neurological deficit after surgical decompression of symptomatic vertebral metastases.

Study Design. We conducted a retrospective study to examination the influence of preoperative duration of symptoms on the clinical outcome of patients that underwent surgical decompression because of neurologic deficit in metastatic disease of the spine. Objectives. Our aim was to investigate possible correlations between the duration of neurologic deficit before surgery and postoperative outcome with respect to neural recovery in patients with spinal metastases, and second, based on those results, propose criteria for the timing of surgery in these patients. Summary of Background Data. It has not yet been determined whether the duration of preoperative symptoms has an influence on the postoperative outcome of patients with vertebral metastases. A standardized treatment or protocol defining a strategy of surgical treatment has yet to be designed. Methods. This study includes 194 patients. The duration of symptoms before surgical treatment and the neurologic status before and after operation were determined and classified according to the Frankel score. Results. Of 401 patients, who underwent surgery due to metastases to the spine, 194 suffered from neurologic deficit. Analyzing the postoperative neurostatus in these patients revealed an improvement in 78 patients (40%), impairment in 13 patients (7%), and in 103 patients it did not change. The relation of duration of neurologic symptoms before surgery, and the outcome after an operation was highly significant (P < 0.001). In patients with less than 3 days of neurologic deficit, the probability of improvement in neurostatus was highly significantly higher (P < 0.001) than in patients with neurologic deficit existing for more than 15 days. Conclusion. Patients with neurologic deficit because of spinal bone metastases benefit from early operative intervention. Urgent surgery is indicated in patients with less than 3 days of neurologic deficit.

Classification of Cerebral Arteriovenous Malformations and Intranidal Flow Patterns by Color-Encoded 4D-Hybrid-MRA

BACKGROUND AND PURPOSE: 4D MRA has been evolving as a noninvasive supplement for DSA. The purpose of this study was to evaluate the feasibility of a newly developed blood flow visualization technique for the classification of cerebral AVMs. We hypothesized that 4D-hMRA allows detection of different flow patterns within the nidus as well as differentiation of feeders and draining veins and has very good agreement with DSA regarding the Spetzler-Martin grade. MATERIALS AND METHODS: Thirty-one consecutive patients with AVMs were evaluated by using 4D-hMRA and DSA by 2 blinded raters. Rating criteria included Spetzler-Martin score and other morphologic variables together with a new scale for 3 intranidal flow patterns (homogeneous = 1, unidirectional = 2, heterogeneous = 3). RESULTS: The Spetzler-Martin grades were rated different from DSA in 5 cases by rater 1 and in 3 cases by rater 2 with an excellent interrater reliability of κ = 0.96 (4/31, 1 by size and 3 by drainage). Each reader missed 5 feeders on 4D-hMRA. Draining veins were distinguished in the temporal course in 7 on DSA but in 8 and 12 on 4D-hybrid-MRA (raters 1 and 2 respectively), with κ = 0.79. A type 1 intranidal flow pattern was recognizable in 9 (30%) patients; type 2, in 19 (60%); and type 3, in 3 (10%). CONCLUSIONS: 4D-hMRA allows reliable Spetzler-Martin grading and detection of brain arteriovenous malformation feeding arteries and draining veins, with the drawback that for small vessels DSA is still needed. Draining veins might even be detected with higher sensitivity than on DSA. Discrimination of different intranidal flow patterns is possible, but their relevance for hemorrhage risk assessment and therapy planning requires further study.

Patient satisfaction after anterior cervical discectomy and fusion is primarily driven by relieving pain.

Objectives:A prospective follow-up study of patients with anterior cervical discectomy and fusion (ACDF) for single-level cervical disc disease was conducted to determine the extent of impact of pain, sensory function, motor function, and range of motion (ROM) of the neck on patient satisfaction after ACDF. Methods:A total of 67 ACDF patients were monitored by clinical examination (pain, motor function, sensory function, and ROM in the neck) preoperatively and at follow-up (mean, 217 d after surgery; range, 198 to 232 d) and by a satisfactory questionnaire (SQ) at follow-up only. According to the SQs, 4 patient groups were characterized. Inside each patient group for each examination parameter, the percentage of patients who showed improved, unchanged, or worsened clinical results was analyzed. Results:Patient satisfaction was found to depend primarily on the improvement in pain (P=0.001). The development of motor function (P=0.056), sensory function (P=0.225), and ROM of the neck (P=0.565) did not demonstrate significant correlation with patient satisfaction. The Numerical Rating Scale score decreased from 6.2 before surgery to 2.1 on follow-up, whereas the level of analgesic use (World Health Organization scheme) decreased from 1.9 to 0.3. Discussion:Improvement in pain seemed to be most important aspect in ACDF patients regarding the subjective SQ. Therefore, we strongly recommend focusing on pain-reducing therapies when choosing treatment for these patients during the postoperative period.

Therapeutic Clues In Spinal Dural Arteriovenous Fistulas - A 30 Year Experience Of 156 Cases

BACKGROUND Spinal dural arteriovenous fistulae (SDAVF) are rare but remain the most common type of spinal vascular malformations. Treatment options for SDAVF include endovascular embolization, microsurgical dissection or a combination of both. But the optimal treatment paradigm has yet to be defined and may well be an individualized interdisciplinary combinatorial approach. MATERIAL AND METHODS From 1980 to 2008, 156 patients with the diagnosis of SDAVF were treated by neuroradiological and neurosurgical means. Based on the procedure-related complications we retrospectively analyzed our data to elucidate the reasons for endovascular failure and the evolution of the surgical technique. RESULTS 156 patients were included in this study. There were 31 (19.9%) female and 125 (80.1%) male patients. Average age at the time of diagnosis was 60.8 years. 102 out of 156 (65.4%) underwent endovascular obliteration, 54 (34.6%) patients were treated primarily by surgery. 134 (85.9%) underwent follow-up examination. A total of 29 (18.6%) out of 156 patients could not be treated successfully by endovascular (9.4%) or surgical (4.1%) means. CONCLUSION Microsurgery can be recommended as the first choice treatment when the fistulas point is unmistakably identified intradurally. Endovascular obliteration may be justifiable in cases with an easy access to a monoradicular feeding artery during diagnostic angiography. Surgery is a definitive treatment with stable long-term results in which procedure-related morbidity is low. During evolution of the combined approach, endovascular coil placement for correct localization of the fistula and the use of intraoperative micro-Doppler was found to be very helpful in increasing the safety of the surgical procedure and minimizing surgical exposure.

Management of Cerebral Arteriovenous Malformations Associated with Symptomatic Congestive Intracranial Hypertension

We report on management strategies and clinical outcomes in 4 cases of acute symptomatic congestive intracranial hypertension associated with cerebral arteriovenous malformations (AVMs). Congestion resulted from high-volume shunts exhausting the drainage capacity of the cerebral venous system in 3 patients, and from sudden venous outflow obstruction in 1 patient. Two AVMs were suggested to be surgically accessible, whereas two AVMs were deemed to be inoperable. Surgically accessible AVMs were treated with embolization followed by complete surgical resection. Inoperable AVMs were treated with partial embolization. Both AVM embolization followed by surgical resection and partial AVM embolization effectively reduced intracranial pressure and achieved sustained patient recovery. Hence, an endovascular approach may be considered to manage AVM-related congestive intracranial hypertension either in combination with surgical AVM removal, or as a palliative approach in inoperable AVMs.