Massimiliano Visocchi

Craniocervical junction instability: instrumentation and fusion with titanium rods and sublaminar wires. Effectiveness and failures in personal experience.

Summary. Background: The aim of the study was to evaluate the effectiveness, pitfalls and failures of instrumentation and fusion with titanium wires and rods in 12 h patients with craniovertebral junction instability. Methods: Among nine adult patients (mean age 48.11 years) with craniovertebral junction instability, four had basilar impression, three metastatic disease, one rheumatoid arthritis and one Downs syndrome. Three children (mean age 7.33 years) with genetic (Downs syndrome, 2 cases) and metabolic (mucopolisaccarydoses type IV, i.e. Morquio Syndrome, 1 case) disease were studied as well. Each patient underwent preoperative radiological evaluation by means of X-Ray, CT scan and MRI of the craniocervical region. Occipitocervical instrumentation with a titanium U-shaped wired rod was performed in each patient. Autologous bone fusion was performed in all but the two cancer patients, in whom polymethylmetacrylate was used. Postoperatively, all the patients used an external orthosis for 3–6 months. Post-operative X-Ray, CT and MRI were performed on each patient. The Frankel clinical scale was used to asses the outcome at follow-up which ranged from 1 to 10 years. At maximum follow up, there was either clinical improvement or stabilization recorded in all but one patient. This patient with basilar impression transiently worsened from grade D to C and a spinal cord lesion was already evident before the operation on MRI examination. Interpretation: The effectiveness of surgical management of craniovertebral junction instability by instrumentation and fusion was demonstratedly in our experience. Nevertheless, the choice of the surgical technique should be made with caution when a spinal cord lesion is revealed by preoperative neuroimaging studies.

Effectiveness and safety of microvascular decompression surgery for treatment of trigeminal neuralgia: a systematic review.

Abstract Microvascular decompression has been now accepted worldwide as a reasonable treatment for trigeminal neuralgia, yet, as a functional operation in the cerebellopontine angle, this process may be risky and the postoperative outcomes might not be good enough sometimes. To assess the effectiveness and safety of microvascular decompression for treatment of trigeminal neuralgia, we conducted a systematic review. Using the keywords “trigeminal neuralgia”, “microvascular decompression”, or “neurovascular conflict”, manuscripts published in English-language journals and indexed in PubMed between January 1, 2000 and June 1, 2013 on the treatment of trigeminal neuralgia (TN) with microvascular decompression were considered for this study. The success and complications were analyzed. The success in this investigation was defined as complete pain free. Continuous outcomes were summarized using means or medians, and dichotomous outcomes were presented as percentage associated with 95% confidence interval. Twenty-six papers with 6,847 patients were finally enrolled in this review. Among them, the male-to-female ratio was 1:1.4, the left-to-right ratio was 1:1.6, and the pain was located in the innervation of V3 and/or V2 in most of the cases with only 2.3% (0.1–4.7) of V1 exclusively. The average age at surgery was 60.9 years (52.5–64.1) with TN symptoms duration of 24.7 months (6.1–42.1) before microvascular decompression (MVD). Operative findings confirmed the superior cerebellar artery, anterior inferior cerebellar artery, posterior inferior cerebellar artery, and multiple vascular contacts (including veins) as the most common sources of nerve compression. The average follow-up duration was 35.8 months (26.2–56.6). The success rate was 83.5% (79.6–89.1). Complications included incisional infection in 1.3% (0.1–2.5), facial palsy 2.9% (0.5–6.2), facial numbness 9.1% (1.3–19.6), cerebrospinal fluid leak 1.6% (0.7–2.5), and hearing deficit 1.9% (0.2–3.9). The postoperative mortality was 0.1% (0.02–0.2). Accordingly, MVD is the most effective treatment for patients with trigeminal neuralgia. An immediate pain free can be achieved by an experienced neurosurgeon with good knowledge of the regional anatomy. To avoid complications, each single step of the process cannot be overemphasized.

Spinal Cord Stimulation and Cerebral Blood Flow: An Experimental Study

Spinal cord stimulation (SCS) affects peripheral, coronary and cerebral blood flow (CBF) in humans. In 1986 Meglio et al. [Appl Neurophysiol 1986;49:139-146] advocated a functional reversible sympathectomy as one of the mechanisms of SCS in man. An experimental animal model was developed to study SCS effects on CBF and to investigate the possible mechanisms. Twenty-one white New Zealand rabbits were anesthetized with Fluothane; spontaneous ventilation was permitted. A steady hemodynamic and metabolic state was maintained. A small cervical laminectomy was performed and an electrode (Medtronic Sigma 3483) was placed in the epidural space over the posterior spinal cord. Both common carotid arteries were exposed and external carotid arteries were ligated. In 3 animals, the cervical symapthetic trunk (CST) was exposed and wrapped with bipolar hook-stimulating electrodes. SCS was performed for 20 min with electrical square waves of 210 microseconds duration, 80 cycles/s, at 2/3 motor threshold intensity. CST stimulation was delivered for 1 min with the following parameters: 10 V, 10 cycles/s, 0.5 ms duration. CBF velocities of both internal carotid arteries were measured by using a CW Doppler (in all the animals) and electromagnetic flowmeter (in 2 animals), at rest, during sympathetic trunk stimulation, during SCS, during simultaneous SCS and CST stimulation. During SCS, an increase of CBF was detected in 11 rabbits (52.4%); a decrease was observed in two cases (9.5%). No change was detected in the remaining 8 animals (38%). CST stimulation induced a decrease of CBF in all animals. Electromagnetic flowmetry confirmed velocitometric findings in the 2 cases studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal Cord Stimulation in Low Back and Leg Pain

We have reviewed our experience with spinal cord stimulation (SCS) in patients with low back and leg pain. 33 patients complaining of leg and low back pain underwent percutaneous tests of SCS. 28 patients had failed back surgery syndromes, 1 patient had pain related to an L1 vertebral body fracture, another from Tarlow cysts and the remaining 3 patients had lumbosacral spondyloarthrosis and osteoporosis without radiological signs of root compression. 28 patients showed mono- or pluriradicular deficits. At the end of the test period (5-65 days), 21 patients (63.6%) reported more than 50% of pain relief (mean analgesia 75%) and were submitted to chronic stimulation. The mean follow-up was 45.5 months. At maximum available follow-up, 40% of the patients (13 out of the 33 initial patients) were successfully using the stimulator (mean analgesia 66.6%).

Spinal Cord Stimulation and Early Experimental Cerebral Spasm: The “Functional Monitoring” and the “Preventing Effect”

Summary Background. Clinical and experimental data on cerebral blood flow (CBF) changes during spinal cord stimulation (SCS) were published since 1986. The aims of the present work are: 1. To find an experimental model of reliable, simple and in vivo monitoring of “early” basilar artery spasm after subarachnoid haemorrhage (SAH) and 2. To investigate the effects of cervical spinal cord stimulation (CSCS) on it. Vasospasm due to SAH is both “acute” and “recurrent”. Early spasm occurs within minutes of the SAH, its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. To overcome intracranial surgical manipulations and biological effects of contrast and fixation media we designed a model that allows “ in vivo” functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interference. Subsequently we investigated the effects of CSCS on the new model of “functional monitoring” of the “early” cerebral vasospasm. Method. 29 adult Burgundy rabbits were studied. Group 1: under homeostatic monitoring, “on-line” carotid blood flow (carotid BF) changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH and up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. Carotid BF increase during basilar vasospasm was defined “functional monitoring” of early spasm. Group 2: Twelve animals wearing a cervical epidural electrode underwent carotid BF “functional monitoring” of early basilar spasm before and during CSCS. Findings. Carotid BF changes during CSCS occurred in 10 animals. No carotid BF changes (i.e. no basilar vasospasm) occurred after SAH up to the end of the experiments in all the stimulated animals. Interpretation. CSCS is able to prevent “early spasm” due to SAH in all the animals studied with the new model of “functional monitoring” described, independently from the occurrence and the sign for stimulation-induced carotid BF variations. The role and the limits of reversible functional sympathectomy in mediating the effect of CSCS on early vasospam are discussed.

Cerebral Blood Flow Velocities and Trigeminal Ganglion Stimulation

Transcranial Doppler sonography (TCD) patterns of middle cerebral arteries (MCA) were recorded in 10 patients before and during unilateral trigeminal ganglion stimulation (TGS). During TGS, TCD flow velocity significantly decreases in all patients: on both sides in 2 patients, only ipsilaterally to the TGS in 7 patients, and only on the opposite side in the remaining patient. In 2 patients, a controlled progressive hypercapnia test was performed before and during TGS. An enhanced vascular response to increased CO2 concentrations was observed during TGS.

Spinal cord stimulation and cerebral blood flow in stroke: personal experience.

Spinal cord stimulation (SCS) can increase cerebral blood flow (CBF) and improve stroke patients. In order to better understand the haemodynamic changes underlining the clinical improvement, we have studied with transcranial Doppler (TCD), SPECT and NIRS 18 patients harbouring a stroke. SPECT Group: An increase of regional CBF during SCS was measured far from the stroke areas in 9 patients, further decrease in CBF was found in 2, no changes in 1. TCD Group: An increase of CBF velocities during SCS was found in 4 patients, no changes in 6, a decrease in 1. NIRS Group: Data consistent with and increase in CBF were obtained during SCS in the only patient undergone such a study. In 6 patients studied with different techniques, data obtained fitted only in 2 patients. In 3 patients no changes in TCD faced with changes in SPECT. In one case an improvement in TCD was evident in the left while an improvement of SPECT was shown in the right site. SCS is a valid therapeutic tool in stroke patient even if, as matter of fact, parallelism between clinical and haemodynamic changes during SCS is not demonstrated in our patients, rising the question on the role of ischemic penumbra in mediating clinical improvement.

Cerebral Hemodynamics During Spinal Cord Stimulation

An increase of cerebral blood flow (CBF) during spinal cord stimulation (SCS) has been shown in man using the 133Xenon inhalation technique. We report the effects of SCS on cerebral hemodynamics studied with transcranial Doppler sonography (TCD). Twenty‐six patients with epidural electrodes implanted at the cervical level (11 patients) and at the thoracic level (15 patients) were investigated with recordings of CBF velocity in the middle cerebral arteries before and during SCS, Sixty‐three and two‐thirds percent of patients with cervical stimulation and 29.4% of patients with thoracic stimulation showed a decrease afcerebral vas‐cularresistance simultaneously with an increase of the velocity of CBF.

Videoassisted anterior surgical approaches to the craniocervical junction: rationale and clinical results

PurposeIn this narrative review, we aim to give an update on the anatomic fundamentals of endoscopic assisted surgery to the craniocervical junction (transnasal, transoral and transcervical), and to report on the available clinical results.MethodsA non-systematic review and reporting on the anatomical and clinical results of endoscopic assisted approaches to the craniocervical junction (CVJ) is performed.ResultsPure endonasal and cervical endoscopic approaches still have some disadvantages, including the learning curve and the lack of 3-dimensional perception of the surgical field. Endoscopically assisted transoral surgery with 30° endoscopes represents an emerging alternative to standard microsurgical techniques for transoral approaches to the anterior CVJ. Used in conjunction with traditional microsurgery and intraoperative fluoroscopy, it provides a safe and improved method for anterior decompression with or without a reduced need for extensive soft palate splitting, hard palate resection, or extended maxillotomy.ConclusionsTransoral (microsurgical or video-assisted) approach with sparing of the soft palate still remains the gold standard compared to the “pure” transnasal and transcervical approaches due to the wider working channel provided by the former technique. Transnasal endoscopic approach alone appears to be superior when the CVJ lesion exceeds the upper limit of the inferior third of the clivus. Combined transnasal and transoral procedures can be tailored according to the specific pathological and radiological findings.

Spinal cord stimulation and cerebral hemodynamics: updated mechanism and therapeutic implications

The effects of spinal cord stimulation (SCS) on cerebral blood flow (CBF) are well known based on experimental investigations, and its vasodilator effect on peripheral arteries is widely used in clinical settings in the treatment of peripheral vascular disease. Since Hosobuchi’s [Appl Neurophysiol 1985;48:372–376] first observations on the effects of SCS on CBF were published 22 years ago, many advances have been made in understanding SCS-mediated effects on CBF. This paper reviews the main laboratory observations and analyzes the most significant neurophysiological theories on the SCS-mediated effect on CBF. Most significant experimental data have been discussed, with specific reference to possible mechanisms such as ‘functional reversible sympathectomy’, cerebral infarction and related ischemic edema, hemodynamic deterioration in experimental combined ischemic-traumatic brain injury and cerebral vasospasm. The authors revised the published experiences in humans with hypoperfusion syndromes and ‘adjuvant’ locoregional CBF increase in chemotherapy of brain tumors. SCS represents a new perspective in challenging neurosurgical clinical fields such as cerebral ischemia and vasospasm, and seems promising as a new trend of functional neurosurgery in cerebrovascular diseases.