8.1.1 Symptoms and Signs

• Incidental with symptoms (depending on size and location)

• Loss of smell and taste
• Blurred vision
• Memory loss
• Headaches
• Fatigue/nausea
• Vomiting
• Changes in personality
• Seizures
• Neurological deficits
• Vertigo
• Syncope/fainting
• Symptoms may not be present

8.1.2 Surgical Pathology

• Cranial benign/malignant tumor

8.1.3 Diagnostic Modalities

• Physical examination
• Neurological examination
• Cerebral angiography
• Diffusion tensor imaging (DTI)
• Single-photon emission computed tomography (SPECT) of brain
• MRI of brain (often required to find olfactory groove meningiomas since symptoms are not typically present)
• PET scan of brain
• Optical in vivo imaging (involving bioluminescence and fluorescence)
• Biopsy of tissue

8.1.4 Differential Diagnosis

• Metastatic tumor

  • Breast, colon, lung, melanoma, renal cell
• Primary tumor (may become metastatic)
  • Glioma
    • Astrocytoma (astrocytomas, anaplastic astrocytomas, glioblastomas)
    • Oligodendroglial
    • Mixed glioma (both astrocytic and oligodenrocytic)
  • Meningioma
    • Olfactory groove meningioma (typically benign) (see ▶Fig. 8.1)
      

      

    • Convexity meningioma (notably surgically accessible) (see ▶Fig. 8.2)
      

      

    • Grade I (slow growth, distinct borders)
    • Grade II (atypical)
    • Grade III (malignant/cancerous)
  • Schwannoma
  • Craniopharyngioma
  • Pituitary
  • Primary lymphoma
  • Choroid plexus papilloma/carcinoma
  • Dermoid tumor
  • Hemangioblastoma
  • Posterior fossa tumor
    • Medulloblastoma
    • Pineoblastoma
    • Ependymoma
    • Primitive neuroectodermal tumor (PNET)
    • Astrocytoma of cerebellum and brainstem

8.1.5 Treatment Options

• Acute pain control with medications and pain management
• If tumor is metastatic:
  • Tumor resection surgery (if located in a single area of the brain) followed by radiation therapy
  • Radiation therapy (i.e., whole-brain radiation therapy, WBRT)

  • Immunotherapy (i.e., Yervoy, Opdivo, Keytruda)

  • Intracranial chemotherapy or catheter-mediated chemotherapy (for leptomeningeal metastases); radiation therapy may also be used
  • Targeted therapy
    • Tagrisso for non-small cell lung cancer (NSCLC) with genetic alteration to EGFR gene
    • Alecensa for NSCLC with genetic alteration to ALK gene
    • Tykerb for HER2-positive breast cancer
    • Tafinlar and/or Mekinist and Zelboraf for melanoma
• If tumor is deemed low grade and can be fully removed in one step (tumor is focused in one area):
  • Tumor resection surgery
    • Radiation therapy may be required if tumor cannot be fully removed
    • Transnasal endoscopic surgery if small and easily reachable (typically for olfactory groove meningioma)
    • Craniotomy or minicraniotomy approaches (removing part of the skull to resect tumor)
    • Pterional approach (shortest route to suprasellar cisterns)
    • Embolization performed prior to surgery if meningioma is large and has rich vascular supply
• If tumor is deemed high grade and cannot be fully removed by surgery:
  • Tumor resection surgery if deemed suitable candidate for surgery; may be followed by radiation treatment and chemotherapy (may be supplemented by target therapy) after resection if considered necessary by the radiation oncologist
    • Oncologist will need to determine overall prognosis, Karnofsky performance score, and extent of visceral disease
    • If poor surgical candidate with poor life expectancy, medical management recommended
  • Radiation therapy
    • Conventional Radiation Therapy
    • Three-dimensional conformal radiation therapy (3D-CRT)
    • Intensity modulated radiation therapy (IMRT)
    • Proton therapy
    • Radiosurgery/CyberKnife treatment (primary treatment for metastases)

8.1.6 Indications for Surgical Intervention

• No improvement after nonoperative therapy (physical therapy, pain management, radiation treatment, and chemotherapy)
• Metastasis in single brain location

• Large tumor(s) causing significant mass effect or obstructive hydrocephalus

• Patient does not possess more than four brain lesions from multiple metastases
• Tumor(s) surgically accessible
• Tumor recurrence following other treatments
• Residual tumor(s) present after surgery

8.1.7 Surgical Procedure for Bifrontal Craniotomy (Pre-op Embolization Can Be Done Prior to Surgery)

1. Informed consent signed, preoperative labs normal, patient ceases intaking of NSAIDs (Naprosyn, Advil, Nuprin, Motrin, Aleve) and blood thinners (Coumadin, Plavix, Aspirin) 1 week prior to treatment
2. Maintain patients with preoperative seizures on antiepileptic for 1 year
3. Patient’s head is shaved and skin overlaying surgical site is cleansed with antiseptic solution
4. Appropriate intubation and sedation and lines (if necessary) as per the anesthetist
5. Intravenously administer 1 g third-generation cephalosporin antibiotic, 10 mg dexamethasone, 1 g phenytoin
6. Place patient in supine position on operating table, with Mayfield Pin fixation and minor head extension, and all pressure points padded
7. Neuromonitoring not needed
8. Time out is performed with agreement from everyone in the room for correct patient and correct surgery with consent signed
9. Incise skin from zygoma to zygoma, within 1 cm of tragus (avoiding injury to superficial temporal artery)
10. Turn skin flap and administer 200 mL mannitol
11. Open the dura and raise pericranium and its pedicle of blood vessels, to be used in reconstruction of anterior skull base
12. Place two burr holes bilaterally at keyholes on frontosphenoid suture, 6 mm posterior to frontozygomatic suture
13. Place one burr hole on each side of sagittal sinus in midline (to straddle sinus)
14. Release sinus dura from undersurface of bone using blunt Penfield dissector
15. Complete craniotomy using craniotome, incorporating frontal sinus flushed with anterior cranial base
16. Cranialize frontal sinuses by removing its mucosa and posterior wall

17. Remove crista galli

18. Perform dural coagulation on dural vessels
19. Bring microscope into operating field for use in remaining steps
20. Elevate dura from anterior cranial base and devascularize extradural tumor
21. Coagulate anterior and posterior ethmoidal arteries
22. Open dura in straight line along frontal poles
23. Suture sagittal sinus and cut along falx, just above the crista galli
24. Retract frontal lobes to approach tumor (facilitated by draining cerebrospinal fluid [CSF] from nearby cisterns), using suction tip
25. Perform extracapsular coagulation and internal debulking
26. Move capsule toward center and develop a plane between capsule and surrounding brain
27. Meningiomas are situated in subdural space outside the arachnoid
28. Remove tumor from anterior to posterior until optic apparatus and anterior cerebral arteries and branches are visible
29. Carefully separate tumor capsule from this structure
30. If tumor invades into optic canal, remove it by sectioning falciform ligament and decompressing optic nerve
31. If tumor invades into upper half of ethmoid sinuses, remove it by entering ethmoid sinuses from above, angling microscope into the sinus, releasing slightly more CSF from lumbar drain with minimal retraction applied to frontal lobe
32. Reconstruct anterior cranial base
    1. Vascularized pericranium previously raised as a separate layer during procedure is reflected inferiorly in wet gauze
    2. After tumor removal and drilling the hyperostotic bone, lay vascularized pericranium over base of anterior cranial base
    3. Apply two stitches on each side of base of anterior fossa
    4. Place subgaleal drain if deemed necessary
    5. Close dura in standard fashion
    6. Close galea and skin in standard fashion

8.1.8 Pitfalls

• Neurologic deficits
• Vascular injury during tumor resection
• Frontal lobe retraction-related injury
• Olfactory loss
• Postoperative seizure
• Reduction in visual acuity

8.1.9 Prognosis

• Patient will be taken to a recovery room and ultimately to the intensive care unit (ICU). Hospitalization rates depend on the type of procedure performed, preoperative examination status, and patient’s age/comorbidities (discharge after 2–7 days typical).

• Patient will have to enroll in rehabilitation unit for several days after hospital stay
• Patient will have sequential compression devices (SCDs) placed on legs while in bed to reduce chance of blood clot formation
• Headache, nausea, or vomiting, if present following the procedure, will warrant relevant medications
• Abstain from heavy lifting for 2 weeks
• Patients without preoperative seizures are placed on antiepileptic for 1 week postoperatively

8.2.1 Symptoms and Signs (Broad)

• Incidental with symptoms (depending on size and location)
• Headaches progressively increasing in frequency and severity
• Nausea and/or vomiting
• Blurred vision, double vision, or loss of peripheral vision
• Difficulty maintaining balance
• Reduction in sensation or motor control of certain extremities
• Difficulty producing speech
• Changes in behavior/reduction in awareness
• Seizures
• Reduction in hearing capabilities

8.2.2 Surgical Pathology

• Cranial benign/malignant tumor

8.2.3 Diagnostic Modalities

• Physical examination
• Neurological examination
• Cerebral angiography DTI
• SPECT of brain
• MRI of brain (see ▶Fig. 8.3 and ▶Fig. 8.4)
  

  

  

• PET scan of brain
• Optical in vivo imaging (involving bioluminescence and fluorescence)
• Biopsy of tissue

8.2.4 Differential Diagnosis

• Metastatic tumor
  • Breast, colon, lung, melanoma, renal cell
• Primary tumor (may become metastatic)
  • Glioma
    • Astrocytoma (astrocytomas, anaplastic astrocytomas, glioblastomas)
    • Oligodendroglial

      Mixed glioma (both astrocytic and oligodenrocytic)

  • Meningioma
    • Grade I (slow growth, distinct borders)
    • Grade II (atypical)
    • Grade III (malignant/cancerous)
  • Schwannoma
  • Craniopharyngioma
  • Pituitary
  • Primary lymphoma
  • Choroid plexus papilloma/carcinoma
  • Dermoid tumor
  • Hemangioblastoma
  • Posterior fossa tumor (see ▶Fig. 8.5 and ▶Fig. 8.6)
    

    

    

    • Medulloblastoma
    • Pineoblastoma
    • Ependymoma
    • PNET
    • Astrocytoma of cerebellum and brainstem

8.2.5 Treatment Options

• Acute pain control with medications and pain management
• If tumor is metastatic:
  • Tumor resection surgery (if located in a single area of the brain) followed by radiation therapy
  • Radiation therapy (i.e., WBRT)
  • Immunotherapy (i.e., Yervoy, Opdivo, Keytruda)
  • Intracranial chemotherapy or catheter-mediated chemotherapy (for leptomeningeal metastases); radiation therapy may also be used
  • Targeted therapy
    • Tagrisso for NSCLC with genetic alteration to EGFR gene
    • Alecensa for NSCLC with genetic alteration to ALK gene
    • Tykerb for HER2-positive breast cancer
    • Tafinlar and/or Mekinist and Zelboraf for melanoma
• If tumor is deemed low grade and can be fully removed in one step (tumor is focused in one area):
  • Tumor resection surgery
    • Radiation therapy may be required if tumor cannot be fully removed
    • Transnasal endoscopic surgery if small and easily reachable (typically for olfactory groove meningioma)
    • Craniotomy or minicraniotomy approaches (removing part of the skull to resect tumor)
    • Pterional approach (shortest route to suprasellar cisterns)
    • Embolization performed prior to surgery if meningioma is large and has rich vascular supply
• If tumor is deemed high grade and cannot be fully removed by surgery:
  • Tumor resection surgery if deemed suitable candidate for surgery; may be followed by radiation treatment and chemotherapy (may be supplemented by target therapy) after resection if considered necessary by the radiation oncologist

    • Oncologist will need to determine overall prognosis, Karnofsky performance score, and extent of visceral disease

    • If poor surgical candidate with poor life expectancy, medical management recommended
  • Radiation therapy
    • Conventional radiation therapy
    • 3D-CRT
    • IMRT
    • Proton therapy
    • Radiosurgery/CyberKnife treatment (primary treatment for metastases)

8.2.6 Indications for Surgical Intervention

• No improvement after nonoperative therapy (physical therapy, pain management, radiation treatment, and chemotherapy)
• Metastasis in single brain location
• Large tumor(s) of over 3 cm causing significant mass effect or obstructive hydrocephalus
• Patient does not possess more than four brain lesions from multiple metastases
• Tumor(s) surgically accessible
• Tumor recurrence following other treatments
• Residual tumor(s) present after surgery

8.2.7 Surgical Procedure for Craniotomy

1. Informed consent signed, preoperative labs normal, patient ceases intaking of NSAIDs (Naprosyn, Advil, Nuprin, Motrin, Aleve) and blood thinners (Coumadin, Plavix, Aspirin) 1 week prior to treatment
2. Appropriate intubation and sedation and lines (if necessary) as per the anesthetist
3. Intravenously administer 1 g third-generation cephalosporin antibiotic, 10 mg dexamethasone
4. Patient’s head is shaved and skin overlaying surgical site is cleansed with antiseptic solution
5. Place patient in a position appropriate for reaching the tumor location on operating table, with Mayfield Pin fixation, and all pressure points padded
6. Neuromonitoring not needed
7. Time out is performed with agreement from everyone in the room for correct patient and correct surgery with consent signed
8. Incise skin in location appropriate for reaching the location of tumor

9. Pull the scalp up and clip it to control bleeding, allowing access to brain

10. Make burr holes in the skull using a medical drill and carefully cut the bone using a saw, if necessary
11. Remove the bone flap, saving it for future steps
12. Separate the dura mater from the bone and cut it, exposing the brain
13. Microsurgical instruments may be utilized to better distinguish abnormal and healthy tissues in relevant brain structures
14. Ensure that all surgically accessible tumor components have been resected and that hemostasis has been achieved
15. Suture the dura mater
16. Reattach the bone flap using plates, sutures, or wires
    1. If a tumor or infection is present in the bone, do not reattach it
    2. If decompression is required, do not reattach the bone flap
17. Close skin incision with sutures or surgical staples
18. Apply sterile bandage or dressing over incision

8.2.8 Pitfalls

• Recurrence of tumor(s) after surgery
• Neurologic deficits
• Vascular injury during tumor resection
• Blood clots
• Pneumonia
• Seizures
• Brain swelling
• CSF leakage
• Paralysis, memory deficits, difficulty producing speech, diminished balance, and/or coma (rare)