Giuseppe Talamonti

Surgical treatment of intracranial dural arteriovenous fistulae : role of venous drainage

OBJECTIVE This report focuses on the surgical management of aggressive intracranial dural arteriovenous fistulae (d-AVFs), which are defined as fistulae with arterialized leptomeningeal veins (red veins). Particular attention is paid to the accurate identification of the venous drainage pattern and to the choice of the proper treatment strategy. METHODS Thirty-four consecutive patients with aggressive intracranial d-AVFs were treated between 1994 and 1998. Angiographic studies allowed the identification of two main types of aggressive lesions, i.e., d-AVFs with sinus drainage and reflow into leptomeningeal veins (12 patients), which we designated sinus fistulae, and d-AVFs drained exclusively by leptomeningeal veins without sinus interposition (22 patients), which we designated nonsinus fistulae. All patients underwent surgical treatment, which consisted of resection of the fistulous sinus tract in 12 cases of sinus fistulae and interruption of the draining veins at their dural origin in 22 cases of nonsinus fistulae. Surgical preparation via multistage transarterial embolization was required in all 12 cases of sinus fistulae and in 4 of 22 cases of nonsinus fistulae. RESULTS The mortality rate was 0%, and there were no instances of lasting morbidity. Radioanatomic cures were achieved in all cases. There was no case of venous hypertension or venous infarction after resection of the affected sinus or interruption of the draining veins. No arteriovenous shunts recurred during the follow-up period. CONCLUSION Careful preoperative identification of the venous drainage pattern seems critical for planning of the correct surgical strategy to treat aggressive intracranial d-AVFs. If the fistula exhibits sinus drainage with reflow into leptomeningeal veins, surgical excision of the fistulous sinus segment represents a safe and definitive treatment option. In these cases, the affected sinus may be safely removed, provided that preoperative angiograms demonstrate participation of the sinus in drainage of the lesion, indicating that the sinus is nonfunctional. Conversely, if the fistula exhibits pure leptomeningeal drainage, the sinus does not participate in drainage of the lesion and cannot be excised. In these cases, the best treatment involves interruption of the draining veins at the point at which they exit the dural wall of the sinus. This simple easy treatment has been proven to be safe and highly effective in permanently eliminating arteriovenous shunts.

The Craniovertebral Junction Area and the Role of the Ligaments and Membranes

Traumatic injuries of the craniovertebral junction (CVJ) area are common and frequently the outcome of motor vehicle accidents, falls, and diving accidents. To define and characterize CVJ traumatic injuries, some international classifications are currently in use, and they are thought and focused on junction bone fracture. However, recent data point out a major important role of the CVJ ligaments and membranes in traumatic injuries with a secondary function of the osseous structures. Emphasizing the correct role of the ligaments and membranes is extremely important for determining appropriate medical or surgical planning for patients and also to design new CVJ injury classifications. We reviewed every recent major publication on the ligaments and membranes of the CVJ area. We divided the information into sections concerning anatomy, embryology, biomechanics, trauma, and CVJ bone fractures. A role of the ligaments and membranes in the traumatic injuries of the CVJ area has often been recognized; but only recently, with the increase in the knowledge of the anatomic and biomechanical junction area, supported by neuroradiological tools (magnetic resonance imaging) and a more detailed traumatic injuries assessment, has the role of the ligaments and membranes been highlighted. Ligaments and membranes have a pivotal role in each junctional ability and are the key to orienting any medical or surgical indications in this unique area of the spine.

Anterior approach to thoracic and lumbar spine lesions: results in 145 consecutive cases

OBJECT The authors report on a series of 145 consecutive patients with different types of spine lesions surgically treated via an anterior approach (AA) at the thoracic and lumbar levels during the past 10 years. Indications, techniques, and surgical results are described. METHODS This series included 92 patients with fractures, 30 with neoplasms, 13 with thoracic disc hernias, and 10 with spinal infections. Based on the lesion to be addressed, the AA was used for lesion excision, corpectomy, vertebral body reconstruction with cages, realignment, and/or plating or screwing. The approach was extracavitary in 55 patients and intracavitary in 90. In 126 patients (86.8%), neural decompression and spine stabilization were achieved via a stand-alone AA (SA-AA), whereas 19 patients (13.1%) were treated using a 2-stage anteroposterior approach. This circumferential approach was reserved for select cases of severe traumatic dislocation, particular types of tumors, or specific anatomical locations. The authors developed a simple neuronavigation-based method of identifying the severely injured patients who were eligible for the SA-AA by evaluating the angle of lateral dislocation. RESULTS There were no deaths and no instances of major surgery-related morbidity. Minor morbidity was almost always transitory and was reported in 13 patients (8.9%). Neurological improvement was reported in 20% of injured patients with a preoperative incomplete lesion. Postoperatively, all patients were able to stand or at least sit without load pain. During the follow-up (mean +/- standard deviation 3.8 +/- 2.4 years), there were no cases of failure, fracture, dislocation, or bending of the anterior instrumentation, and the rate of pseudarthrosis was 0%. CONCLUSION The anterior route provides direct access to most spine diseases and allows optimal neural decompression and the possibility of adequate realignment and strong reconstruction/fixation. Stability of the vertebral column is achieved, resolution of clinical pain is rapid and almost complete, and the rate of surgical complications is very low. The authors assert that the SA-AA offers so many advantages and has such good results that the 2-stage anteroposterior approach can be reserved for a minority of select cases and that the time for using the posterior approach alone is over.

Experimental studies on spinal cord injuries in the last fifteen years

Experimental studies on spinal cord (SC) injuries published from 1975 to 1989 in some of the most widely circulating neurosurgical journals were reviewed. The relatively large number of animal species utilized as well as the intensely variable dynamic or static methods employed to induce SC injury represent elements of confusion more than objective necessities in this field of research. In fact, the objective of SC injury research should be to solve the problem of severe SC injuries by either preventing and/or repairing SC damage, rather than looking for modalities to provoke a large spectrum of SC injuries with the result of establishing a correlation between for example, the clinical picture and trauma magnitude. It should be time to study all variables and treatments mainly in only one experimental model. The rat with a permanent paraplegia should represent such a model; the abdominal aorta occlusion for 45 minutes, distal to the renal arteries in rabbits should be the experimental model of choice for ischaemia. If a significant result, such as reversing permanent paraplegia, were obtained in rats, it would be logical to repeat the study in higher mammals and if successful, in humans. For the last decade of this century it is necessary to further study all the mechanisms implied in secondary SC damage as well as to attempt to repair definitive SC damage by using grafts and enhancing the potential regenerative ability of the SC with known and new growth factors. Presently, methylprednisolone, dexametasone, thiopental, naloxone, and hypothermia seem to have some clinical potentials that require studies in humans.

Spinal dural arteriovenous fistulas: outcome and prognostic factors.

The aim of this study is to review the clinical outcome of patients treated for spinal dural arteriovenous malformations and investigate the presence of pretreatment indicators of outcome after short- and midterm follow-up. The authors retrospectively reviewed the records of 65 consecutive patients treated either surgically or endovascularly in 3 neurosurgery departments between 1989 and 2009. After treatment, 80% of patients reported improvement of at least 1 symptom. Motor symptoms improved more than sensory disorders, pain, or sphincter impairment. Spinal dural arteriovenous fistulas at the thoracic level, and in particular at the lower level, responded better than those in other spinal areas. Spinal dural arteriovenous fistula is a rare pathology with a malignant course that should be treated aggressively. This study appears to confirm that neurological status before treatment, anatomical location of the fistula, and symptoms at presentation are all factors that can predict outcome. Early diagnosis of spinal dural arteriovenous malformations in the lower thoracic area in patients with an Aminoff scale score < 3 was associated with the most favorable outcome.

Intracranial Cysts Containing Cerebrospinal Fluid-Like Fluid: Results of Endoscopic Neurosurgery in a Series of 64 Consecutive Cases

BACKGROUND:Intracranial cysts containing cerebrospinal fluid (CSF) may be developmental or acquired. OBJECTIVE:To analyze the results of endoscopic neurosurgery in the management of intracranial CSF cysts. METHODS:In a 7-year period, 64 consecutive patients underwent endoscopic neurosurgery for CSF cysts. Group 1 consisted of 13 patients with acquired cysts; group 2 included 51 patients with developmental cysts. In all cases, the cyst walls were fenestrated through small burr holes with frameless guided operative endoscopes. Follow-up ranged from 1 to 6 years (mean, 3.4 years). RESULTS:There were no mortality and no permanent morbidity, apart from a patient (1.6%) who remained neurologically intact but required ventriculoperitoneal shunting because of intraoperative hemorrhage. The planned fenestrations could be performed in all patients except 2, owing to thick, opaque cyst walls. In group 1, 6 patients fully recovered and remained intact throughout the follow-up, whereas 7 improved but had various degrees of neurological disabilities that were related to their initial diseases. Radiological results were excellent in all cases. In group 2, there were 7 asymptomatic patients who remained unchanged and 44 “symptomatic” patients: 40 (91%) clinically improved, 4 (9%) remained unchanged, and none worsened. Cyst size decreased in 37 patients (74%) and remained unchanged in 13 (26%). CONCLUSION:In this series, patients of different ages, harboring cysts of various sizes and locations, could be satisfactorily treated with endoscopic neurosurgery.

Asymptomatic lipomas of the medullary conus: surgical treatment versus conservative management

OBJECT The goal of this study was to compare long-term results of surgery with the outcomes of conservative treatment in patients with asymptomatic lipomas of the conus medullaris. METHODS The parents of 56 consecutive children with a diagnosis of asymptomatic lipoma of the conus medullaris underwent detailed neurosurgical consultation. The pros and cons of both prophylactic surgery and conservative treatment were carefully presented. Both options were offered, and the parents were free to choose the preferred management. A total of 32 children underwent surgical treatment, and 24 were conservatively treated. Afterward, all patients entered the same protocol of serial neurological and urological follow-up at the Centro Spina Bifida. The mean follow-up periods were 9.7 years in the surgical treatment group and 10.4 years in the conservative treatment group. RESULTS Permanent surgical morbidity was 3.1% (1 patient). During follow-up, tethered cord syndrome occurred in 9.7% of the surgically treated patients (3 of 32 patients) and in 29.1% of the conservatively managed children (7 of 24 patients). This difference did not result in statistical significance, but a clear trend in favor of surgery emerged. Young age at surgery and a cord/sac ratio < 50% appeared to be determining factors in the prevention of subsequent tethered cord syndrome. CONCLUSIONS The small size of this series does not provide enough statistical evidence that surgical treatment can really improve the natural history of asymptomatic lipomas of the conus medullaris. Nevertheless, surgery appears at least advisable since it reduces by 75% the odds of TCS (p = 0.067), which is quite close to statistical significance.

Arterial and venous aneurysms associated with arteriovenous malformations.

OBJECTIVE To identify prioritization based on hemorrhagic risk and indications for treatment of arterial and venous aneurysms associated with arteriovenous malformation (AVM). METHODS From a global series of 400 consecutively treated AVMs, 34 patients (8.5%) with 45 arterial or venous aneurysms were extrapolated. These 45 lesions were classified as unrelated aneurysms (n = 5 cases; 11.%), flow-related aneurysms (n = 18 cases; 40%), and intranidal and postnidal venous aneurysms (n = 22; 49.%). The 18 flow-related aneurysms were further divided into remote (n = 6 cases) and adjacent (n = 12 cases) types. Of 45 aneurysms associated with AVMs, 15 were unruptured with a 5-year mean follow-up. Various possible risk indicators were considered and measured by univariate and multivariate analyses. RESULTS During the follow-up period, 1 of 15 unruptured aneurysms bled, and the patient died. A significantly different bleeding incidence was found between unrelated aneurysm and flow-related aneurysm types (P = 0.002). Bleeding was significantly less probable in flow-related remote aneurysm type than in venous and flow-related adjacent aneurysm types (P = 0.007). The location of the aneurysm was the only true risk factor for bleeding; the other parameters had no influence on bleeding. CONCLUSIONS In this series, different subtypes of aneurysms associated with AVMs had different clinical behaviors. The bleeding risk of the unrelated aneurysm and the flow-related remote aneurysm types should be considered almost the same as any other unruptured aneurysm. In other words, bleeding risk should be considered taking into account the parameters established by the International Study of Unruptured Intracranial Aneurysms (location, size, and morphology). Conversely, flow-related adjacent aneurysm and venous aneurysm types have significantly higher bleeding potentials.

The third nerve transection and regeneration in rats with preliminary results on the sixth nerve transection and regeneration in guinea pigs.

The relationship between the phenomenon of the nonselective reinnervation and the functional recovery after section and repair of the highly organized third cranial nerve motor system in rats was studied. The same relationship after section and repair of the more simply organized sixth cranial nerve motor system in guinea pigs is presented as preliminary results. Anatomical demonstration of nonselective reinnervation was obtained by injecting horseradish peroxidase (HRP) into the extraocular muscles. A bilateral reinnervation of previously ipsilateral innervated muscles both in the third and the sixth nerve was interpreted as a plastic response of the brain stem neurons to the nerve injury. Functional recovery, evaluated by measuring with an infrared light technique the horizontal and vertical vestibulo-ocular reflexes, was excellent for the rectus lateralis muscle while it was relatively poor i.e. partial for the muscles depending on the third nerve. These data suggest that one of the most important factors influencing the functional recovery after section and repair of a peripheral nerve is the complexity of the nerve motor system organization.

Traumatic (Type II) Odontoid Fracture with Transverse Atlantal Ligament Injury: A Controversial Event

OBJECTIVE Traumatic (Type II) odontoid fractures are very common injuries. Nevertheless, their connection with transverse atlantal ligament injury is controversial and poorly defined. The aim of this study is to report a single case of traumatic (type II) odontoid fracture with transverse atlantal ligament injury and to critically analyze the role of ligaments and membranes together with neuroradiological tools in the management of craniovertebral junction-traumatized patients. METHODS We report 27 consecutive cases of traumatic (type II) odontoid fractures who underwent magnetic resonance imaging (MRI) in the acute phase injury (<72 hours), focusing our attention on the transverse atlantal ligament. RESULTS One patient (3.7%) demonstrated a transverse atlantal ligament injury on MRI. The patient underwent surgery. CONCLUSIONS Traumatic (type II) odontoid fracture with transverse atlantal ligament avulsion can be considered an unusual event. It is our opinion that the routine use of MRI for all patients with type II odontoid fracture could be unjustified in clinical practice. Strict clinical surveillance of all patients managed conservatively and the use of MRI in selected cases could be a reasonable management option.