Complications in AVM Surgery.

In AVM surgery perioperative complications can arise and can have serious perioperative consequences. Surgically related complications in AVM treatment, in many cases, can be avoided by paying attention to details:1. Careful selection of the patient: - addressing a patient with eloquent AVM to Gamma Knife treatment - preoperative treatment with selective embolization of the accessible deep feeders - preoperative gamma knife or embolize those patient with an over-expressed venous pattern2. Meticulous coagulation of deep medullary feeders: - Using dirty coagulation - Using dry non-stick coagulation - Using micro clips - Using laser - Reaching the choroidal vessel in the ventricle when possible - Avoiding occlusive coagulation with hemostatic agents3. Check and avoiding any residual of the AVM4. Keep the patient under pressure control during postoperative periodFulfilling these steps contributes to reduce complications in this difficult surgery, leading to a safer treatment that compares favorably with natural history of brain arteriovenous malformations.

Traumatic injuries to the craniovertebral junction: a review of rare events.

The craniovertebral junction is a specific region of the spine with unique anatomical and biomechanical properties that yields a wide variety of injury patterns. Junctional traumatic fractures and/or dislocations are widely reported in clinical practice, but we could identify only a subgroup of upper cervical spine traumatic injuries with very few cases reported in the literature, and for this reason may be considered rare. In some of these cases, the absence of spinal biomechanical instability, in association with moderate clinical symptoms (neck stiffness and pain) and the difficulty in fracture identification through standard cervical radiographs, leads to a high percentage of missed injuries. In other cases, traumatic events have been commonly described only in autopsy series due to the high degree of spinal biomechanical instability. Herein, we have summarized all the relevant literature concerning this issue and also included our cases, with the aim of emphasizing prompt diagnosis and correct management. We provide a guide for correctly identifying "rare" craniovertebral junction traumatic injuries.

Single fracture in the atlas vertebral arch: analysis of an unusual event.

STUDY DESIGN: Retrospective study. OBJECTIVE: The aim of this study is to show that a single traumatic fracture of the atlas is unusual but not rare and requires specific management strategies, which can be highlighted by the study of the junctional ligaments and membranes. SUMMARY OF BACKGROUND DATA: A single traumatic fracture of the atlas arch is considered a rare event and has been analyzed in few case reports. Ligaments and membranes play a primary role in providing stability to the craniovertebral junction area. METHODS: Here, we report 10 cases of a single traumatic fracture of the atlas arch: 4 cases were part of our series of spine injuries and were studied by magnetic resonance imaging during the acute phase to assess the junctional ligaments. The remaining 6 cases were obtained from the Literature. RESULTS: Indirect signs of a traumatic ligamentous injury were found only in 1 patient. However, in all cases, these fractures were considered biomechanically stable and all patients were discharged with a rigid collar. During the follow-up, all patients reported an improvement in their neck pain and tenderness, with radiologic signs of bone healing. CONCLUSIONS: A single fracture of the atlas arch is an unusual traumatic event that results from slow-force impact. Medical experience in treating this specific fracture subtype is nowadays poor because of the paucity of the literature; thus, this unusual condition may either be underestimated or even overstudied and overtreated. Nowadays, it seems reasonable to assume that the management should be conservative in all cases and that magnetic resonance imaging often plays only a marginal role.

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.

Cerebellopontine Angle Surgery Assisted by Continuous Mapping of the Facial Nerve Via the Ultrasonic Aspirator.

BACKGROUND: Cerebellopontine angle (CPA) surgery carries the risk of lesioning the facial nerve. The goal of preserving the integrity of the facial nerve is usually pursued with intermittent electrical stimulation using a handheld probe that is alternated with the resection. We report our experience with continuous electrical stimulation delivered via the ultrasonic aspirator (UA) used for the resection of a series of vestibular schwannomas. METHODS: A total of 17 patients with vestibular schwannomas, operated on between 2010 and 2018, were included in this study. A constant-current stimulator was coupled to the UA used for the resection, delivering square-wave pulses throughout the resection. The muscle responses from upper and lower face muscles triggered by the electrical stimulation were displayed continuously on multichannel neurophysiologic equipment. The careful titration of the electrical stimulation delivered through the UA while tapering the current intensity with the progression of the resection was used as the main strategy. RESULTS: All operations were performed successfully, and facial nerve conduction was maintained in all patients except one, in whom a permanent lesion of the facial nerve followed a miscommunication to the neurosurgeon. CONCLUSION: The coupling of the electrical stimulation to the UA provided the neurosurgeon with an efficient and cost-effective tool and allowed a safe resection. Positive responses were obtained from the facial muscles with low current intensity (lowest intensity: 0.1 mA). The availability of a resection tool paired with a stimulator allowed the surgeon to improve the surgical workflow because fewer interruptions were necessary to stimulate the facial nerve via a handheld probe.

Unruptured Versus Ruptured AVMs: Outcome Analysis from a Multicentric Consecutive Series of 545 Surgically Treated Cases.

BACKGROUND: Recent literature strongly challenged indications to perform preventive surgery in unruptured arteriovenous malformation (AVM) claiming that invasive AVM treatment is associated with a significant risk of complications and thus conservative management may be a preferable alternative in many patients. On the other hand, the recent improvement of surgical instrumentation and treatment strategies (both surgical and interventional) yielded better outcomes than those achieved only a decade ago. Therefore, even among specialists, a wide variety of opinions, concerning the treatment of unruptured AVM, can be found. METHODS: This multicenter retrospective study analyzes a consecutive series of 545 surgically treated AVMs in 10 different hospitals in Italy. RESULTS: Patients with AVMs treated after hemorrhage had an unfavorable (modified Rankin Scale score >1) outcome in more than one third (37.69%) of the cases. Conversely, with proper indications, unruptured AVMs treated preventively have a good outcome in 93.8% of cases, increasing to 95.7%, with no death, if only Spetzler-Martin grades 1-3 are considered (P < 0.05). Outcomes on discharge significantly (P < 0.05) improve at 6 months with the disappearance of many of the initial neurologic deficits that turn out to be transient. CONCLUSIONS: In unruptured low-risk AVMs (Spetzler-Martin grades 1-3), over time, the risk of surgery-associated neurologic deficits becomes lower than that linked to spontaneous hemorrhage, with a crossover point at 6.5 years. Because the average bleeding age is less than 45 years, preventive surgery can be advocated to safeguard the patient and overcome the risks associated with the natural history of AVMs.

Use of Laser in Arteriovenous Malformation Surgery.

BACKGROUND: Arteriovenous malformation surgery is particularly demanding owing to the need to control bleeding of small, deep white matter vessels during and after removal of the nidus; this is probably one of the most critical moments of arteriovenous malformation surgery. The aim of this article is to describe a useful technique based on the use of tweezers to temporarily stop the blood flow followed by coagulation with the thulium laser. METHODS: Surgery was performed in 20 patients with unruptured cerebral arteriovenous malformations. In each case, the superficial feeder vessels were easily coagulated with nonstick bipolar tips. The finer and deeper feeder vessels were coagulated with use of tweezers and thulium laser. RESULTS: All patients were treated successfully. Optimal intraoperative hemostasis was achieved. CONCLUSIONS: Results were good with no postoperative complications. Our results could encourage a more standardized use of the described technique.

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.

Venous flow rearrangement after treatment of cerebral arteriovenous malformations: a novel approach to evaluate the risks of treatment.

OBJECTIVE: This study aims to identify the angiographic parameters that could help predict the risks of hyperemic complications (HCs) in the treatment of cerebral arteriovenous malformations (AVMs). METHODS: The charts and the pre- and post-treatment angiographies of 400 consecutively treated patients with cerebral AVMs were retrospectively reviewed. Several parameters were analyzed: grade, size, drainage depth, number of the "recruited veins" (veins coming from the brain and joining the main AVM drainage), and "venous times" (the times of visualization of the nidus and the main drainage, of the "recruited veins," and finally of the normal cerebral veins). On this basis, two groups were identified: group 1, consisting of 309 patients (77.3%) with normal/subnormal venous times, and group 2, consisting of 91 patients (22.7%) with altered venous times and venous engorgement. Finally, the weight of the various parameters was measured by univariate and multivariate analyses. RESULTS: An overall number of 245 patients (61.2%) achieved favorable outcomes. HCs occurred in a total of 28 patients (7%): No patient belonged to group 1, so that these adverse effects were reported in 30.7% of group 2 patients. The presence of deep drainage and the number of recruited veins resulted in statistically significantly different impacts on the risk of the different grades. CONCLUSIONS: The statistical analysis allowed the identification of three different risk scores, which were named Nig-scores (Niguarda scores). Nig-score 0 means no risk of HCs and concerns patients without altered venous times; Nig-score 1 represents patients with intermediate risk, that is, with moderately altered venous times and few recruited veins; Nig-score 2 indicates high risk of HCs and refers to patients with markedly altered venous times.

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.

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.