◦ Perimedullary AVF (Type IV)
– Intradural-intramedullary
– Extradural
• Vertebral sarcoidosis
• Dissection syndromes:
– Cervical internal carotid artery
– Extracranial vertebral artery
Treatment Options
• Conservative observation
• Radiation treatment:
– Conventional radiation: not very effective therapy
Fig. 1.17 (a–g) Radiology revealed an upper cervical intradural arteriovenous fistula (AVF) with an aneurysm in a teenage girl. Several feeding vessels were identified at the fistula. The fistula was surgically treated after reducing its blood flow by placing a coil in the main feeding artery. (Source: Operative procedure. In: Macdonald R, ed. Neurosurgical Operative Atlas: Vascular Neurosurgery. 3rd ed. Thieme; 2018).
Fig. 1.18 (a–e) Radiology revealed a cervical diffuse intramedullary arteriovenous malformation (AVM) in a teenage boy. Feeding vessels were identified to be from the anterior spinal artery and muscular branches. (Source: Relevant anatomy and classification. In: Spetzler R, Kalani M, Nakaji P, eds. Neurovascular Surgery. 2nd ed. Thieme; 2015).
Fig. 1.19 (a, b) Preoperative angiography revealed an unresectable type 2 cervical arteriovenous malformation (AVM). Postoperative angiography (24 months) demonstrates successful treatment of nidus via stereotactic radiosurgery. (Source: Stereotactic radiosurgery of spinal arteriovenous malformations. In: Nader R, Berta S, Gragnanielllo C, et al, eds. Neurosurgery Tricks of the Trade: Spine and Peripheral Nerves. 1st ed. Thieme; 2014).
Fig. 1.20 (a, b) Preoperative angiography and magnetic resonance imaging (MRI) revealed cervical intramedullary arteriovenous malformation (AVM), commonly referred to as glomus AVMs. Postoperative angiography demonstrates successful treatment of AVM. (Source: Spinal intramedullary arteriovenous malformations. In: Albright A, Pollack I, Adelson P, eds. Principles and Practice of Pediatric Neurosurgery. 3rd ed. Thieme; 2014).
– Stereotactic radiosurgery and radiotherapy (nidus must not be greater than 3 cm in diameter)
• Surgery:
– Microsurgical resection
– Preferred option if bleeding or seizures result from lesion
• Endovascular embolization using the following embolic agents (initial procedure to facilitate surgery):
– Coils: close down vessel supplying AVM (cannot independently treat AVM nidus)
– Onyx: solidifies, forming a cast, in vessel supplying AVM (best penetration of AVM nidus)
– NBCA: solidifies as a glue in vessel supplying AVM (greater risks and worse outcomes than with Onyx)
Fig. 1.21 (a–f) Magnetic resonance imaging (MRI) revealed an arteriovenous malformation (AVM) at C2–C3 in a middle-aged woman. Cyberknife treatment was performed, reducing the AVM’s total volume by 75%. Residual AVM was treated with radiation (15 Gy in two fractions). (Source: Conclusion. In: Dickman C, Fehlings M, Gokaslan Z, eds. Spinal Cord and Spinal Column Tumors. 1st ed. Thieme; 2006).
– PVA: used prior to craniotomy or surgical resection of AVM (cannot independently treat AVM pathology)
• Combination techniques:
– Embolization followed by stereotactic radiosurgery
• Venous angiomas should not be treated unless certainly contributing to intractable seizures and bleeding
Indications for Endovascular Intervention
• Preoperative embolization (for surgical AVM resection)
• Presence of associated lesions (aneurysms/pseudoaneurysms on feeding pedicle or nidus, venous thrombosis, venous outflow restriction, venous pouches, dilatations)
• Small surgically inaccessible AVM treated by curative AVM embolization or radiosurgery
• Palliative treatment when symptomatic AVM not entirely treatable by the other approaches
Surgical Procedure for Cervical Spine (Laminoplasty)
1. Administer propranolol 20 mg orally four times a day for 3 days to patient preoperation
2. Informed consent signed, preoperative labs normal, no Aspirin/Plavix/Coumadin/NSAIDs/Celebrex/Naprosyn/other anticoagulants and anti-inflammatory drugs for at least 2 weeks
3. Administer preoperative prophylactic intravenous (IV) antibiotics
4. Appropriate intubation and sedation and lines (if necessary, as per the anesthetist)
5. Patient placed prone on gel rolls, with head clamped via Mayfield pins, pressure points padded, and any hair clipped over upper cervical region
6. Neuromonitoring may be required to monitor nerves (if necessary and indicated)
7. Eyes taped closed and Bair Hugger covers upper body
8. Time out is performed with agreement from everyone in the room for correct patient and correct surgery with consent signed
9. C-arm fluoroscopy equipment set up in operation zone
10. Make an incision over the vertebrae where laminoplasty is to be performed:
a. Prepare to utilize one level above and below the AVM nidus or AVF shunt
b. Extension to ipsilateral pedicle performed if deemed necessary to enhance lateral of the AVM nidus or AVF shunt
11. Perform subperiosteal dissection of muscles bilaterally to expose the vertebra
12. Once the bone is exposed, it is best to localize and verify the correct vertebra via X-ray or fluoroscopic imaging and confirming with at least two people in the room
13. Bovie electrocautery is used to progress dissection toward the spine and to attain hemostasis, with the help of bipolar forceps
14. Move musculature around vertebra laterally and downward to expose the dura
15. Utilize self-retaining retractors to keep everything in place
16. Open the dura, followed by the arachnoid
17. Clip the arachnoid to the dural edges using self-retaining retractors to reveal the AVM
18. Video-angiography (typically with ICG) is used to visualize the blood flow through the AVM
19. If the AVM nidus is intraparenchymal in its entirety, prepare to perform a myelotomy (midline dorsal, dorsal root entry zone, lateral, and anterior midline types). Otherwise,