21. Cut and coagulate the appropriate vessels
22. Separate AVM from the spinal cord using surgical scissors, bipolar, and suction
23. Several nerve rootlets will be tangled with the AVM (they may be tangled with dorsal nerve roots) and must be removed by necessity; others may be left unaltered
24. Cut the dentate ligament where it is attached to the AVM
25. The spinal canal is further exposed, revealing the feeders of the AVM
26. Use video-angiography to confirm no further shunting of the arterial venous blood
27. Close the dura as well as the subcutaneous tissues after the laminoplasty is successfully performed
28. Close the skin with suture, skin-glue, steri-strips, or surgical staples
29. Postoperative injection of the vertebral artery and the thyrocervical trunk demonstrate that the AVM has been treated
Surgical Procedure for Cervical Spine (Laminectomy)
1. Follow AVM laminoplasty procedure above until initial hemostasis is completed and self-retaining retractors are placed, keeping the musculature set aside
2. Use Leksell rongeurs and high-speed burr drill to remove the posterior spinous processes and bilateral lamina
3. Remove the free ligamentum flavum using Kerrison rongeurs to decompress the nerve roots
4. Open the lamina via “green-stick” fracture technique
5. Utilizing Adson Periosteal Elevator, elevate lamina from the side (do not slide underneath it)
6. Fasten plates and screws at the lateral borders of each lamina and the facet joint, decompressing the spinal cord (if needed, often fusion is not necessary)
7. Wash out the wound with antibiotic saline solution and reachieve hemostasis via Bovie electrocautery and bipolar, applying local anesthetic to the wound to reduce bleeding
8. Place a postoperative drain (can be removed after 2–3 days)
9. Close the fascia and subcutaneous tissue with Vicryl
10. Close the skin with suture, skin-glue, steri-strips, or surgical staples
Embolization Procedure (Onyx)
1. Shake Onyx vial on mixer for 20 minutes. Onyx-18 is common, Onyx-34 is suitable for very high flow AVMs, and Onyx-500 is incorporated in aneurysm embolization treatments
2. Wedge microcatheter tip into arterial branch supplying the AVM, preferably very close to the AVM nidus
3. Perform angiography through the microcatheter to confirm that the arterial branch exclusively supplies the AVM
4. Prime the dimethyl sulfoxide (DMSO)-compatible microcatheter (marathon, echelon, rebar, ultraflow) with 0.3 to 0.8 mL DMSO so that Onyx does not solidify in the microcatheter
5. Slowly inject Onyx solution, allowing no more than 1 cm of reflux. If reflux occurs, continue after a 1 to 2 minutes waiting period
6. Halt injection when Onyx no longer flows into the nidus, but refluxes instead
Pitfalls
• Stroke
• Intraoperative and postoperative bleeding
• Failure to remove the entire AVM
• Future recurrence of AVM
• Recompression of cervical spinal cord
• Postlaminoplasty kyphosis
• Nerve root palsies
• Damage to spinal nerves and/or cord
• Postoperative weakness or numbness or continued pain
• Postoperative wound infection
• Prolonged hospitalization due to invasiveness of surgery and other comorbidities/iatrogenic infection
• Temporary postoperative paresthesia
• Iatrogenic vertebral artery injury during embolization process
Prognosis (AVM Laminectomy)
• Hospitalization rates depend on the type of procedure performed, preoperative examination status, and patient’s age/comorbidities
• PT and OT will be needed postoperatively, immediately and as outpatient to regain strength
• Brace/Collar is used for 8 weeks after discharge to immobilize to increase rate of healing
1.3.3 Cervical Anterior and Posterior Techniques for Tumor Resection (Spinal Canal Pathology)
Symptoms and Signs
• Incidental with symptoms (depending on size and location)
• Moderate/Severe numbness to pain, cold, and heat in upper extremities
• Paresthesia in upper body extremities
• Neck pain and loss of mobility due to neck pain
• Radiating pain down the arms
• Pain in moving shoulders
• Muscle weakness in arms (potentially paralysis)
• Inability to conduct fine motor skills with hands
• Scoliosis
Surgical Pathology
• Cervical spine benign/malignant tumor
Diagnostic Modalities
• CT of cervical spine with and without contrast to assess whether there is bony involvement of tumor
• MRI of cervical spine with and without contrast to assess if there is spinal cord, epidural space, or nerve root involvement of tumor
• PET scan of body to look for other foci of tumor
• CT of chest/abdomen/pelvis to rule out metastatic disease
• X-ray (not as reliable for tumor diagnosis)
• Biopsy to examine tissue sample to determine whether tumor is benign or malignant, and what cancer type resulted in the tumor if malignancy is determined
Differential Diagnosis
• Metastatic tumor
– Breast, prostate, lung, renal cell
• Primary tumor
– Schwannoma, neurofibroma, myeloma, plasmacytoma, meningioma, ependymoma, astrocytoma, hemangioblastoma, lipoma, dermoid, epidermoid, teratoma, neuroblastoma, oligodendroglioma, cholesteatoma, subependymoma, osteosarcoma, chondrosarcoma, Ewing’s sarcoma, chordoma, lymphoma, osteoid osteoma, aneurysmal bone cyst, eosinophilic granuloma, angiolipoma (see ▶Fig. 1.22 and ▶Fig. 1.23)
Treatment Options
• Acute pain control with medications and pain management