Cavernoma

Introduction

Cavernous malformations, also known as cavernomas and cavernous angiomas, account for approximately 5% to 15% of all central nervous system vascular abnormalities. They have an incidence that ranges from 0.2 to 0.6 per 100,000 persons per year, with an annual hemorrhage rate that ranges from 0.5% to 11% per patient-year, but they most often present with seizures (50%) as opposed to acute hemorrhage (25%). They are most common among Hispanic Americans, and most are supratentorial but 10% to 25% occur in the posterior fossa. Most advocate for surgical treatment after one hemorrhage for those lesions that are accessible, whereas inaccessible lesions often must have a few symptomatic hemorrhages before treatment is pursued because of the morbidity associated with treatment. In this chapter, we present a case of a patient with a cavernous malformation involving the right middle cerebellar peduncle (MCP).

Example case

Chief complaint: headaches, nausea, vomiting

History of present illness

A 49-year-old, right-handed woman with a history of hypertension presented with recurrent episodes of headaches, nausea, and vomiting. Over the past 6 months, she had recurrent episodes of severe headaches, nausea, and vomiting. After the first episode, she underwent imaging and was diagnosed with a hemorrhagic right MCP cavernoma. She then had a second episode 3 months later and was diagnosed with a rebleed ( Fig. 71.1 ).

Medications : Lisinopril.
Allergies : No known drug allergies.
Past medical and surgical history : Hypertension, hysterectomy.
Family history : No history of intracranial malignancies.
Social history : Store owner, no smoking, occasional alcohol.
Physical examination : Awake, alert, oriented to person, place, time; Cranial nerves II to XII, except slight right facial droop; No drift, moves all extremities with good strength; Right greater than left finger-to-nose dysmetria.

	Evandro de Oliveira, MD, PhD, Joao Paulo Almeida, MD, Mateus Reghin Neto, MD, Institute of Neurological Sciences, São Paulo, SP, Brazil	Nasser M. F. El-Ghandour, MD, Cairo University, Cairo, Egypt	Michael T. Lawton, MD, Barrow Neurological Institute, Phoenix, AZ, United States	Isaac Yang, MD, University of California at Los Angeles, Los Angeles, CA, United States
Preoperative
Additional tests requested	Transesophageal echocardiogram Anesthesia evaluation	CTA DTI CISS MRI	DTI	Cerebral angiogram MRI with gradient echo Audiogram/VEMP
Surgical approach selected	Midline suboccipital craniotomy	Right retrosigmoid craniotomy	Right retrosigmoid craniotomy for trans-MCP vs. telovelar	Right retrosigmoid craniotomy
Anatomic corridor	Right telovelar	Lateral trans-MCP	Trans-MCP vs. telovelar	Lateral trans-MCP
Goal of surgery	Gross total resection, preservation of neurologic tissue	Gross total resection, prevent future bleeding, diagnosis	Gross total resection	Minimize risk of future bleeding
Perioperative
Positioning	Semi-sitting	Right park bench	Right lateral	Right supine
Surgical equipment	Surgical table to semi-sitting position Precordial Doppler IOM (BAERs, EMG cranial nerves) Surgical navigation Surgical microscope Brain retractors Nerve stimulator	Surgical navigation Surgical microscope IOM (BAERs, EMG cranial nerves) Nerve stimulator	Surgical navigation Surgical microscope IOM (BAERs, EMG cranial nerves) Nerve stimulator	Surgical navigation Surgical microscope IOM (MEP/SSEP/BAERs/facial EMG) Nerve stimulator
Medications	Steroids	Steroids	Steroids	Steroids
Anatomic considerations	Squamous part of occipital bone, foramen magnum, posterior arch of C1, transverse and sigmoid sinuses, cerebellum, tonsil, biventral lobule, PICA and branches, floor of fourth ventricle, lateral recess, MCP, cranial nerves VII and VIII	Cranial nerves IV–XI, AICA, SCA, vein of superior cerebellopontine fissure	Cranial nerves V–VIII	Cranial nerves VII–VIII, AICA
Complications feared with approach chosen	Injury to pyramidal tract, lateral/medial lemniscus, cranial nerves V/VII/VIII, vascular injury to PICA/AICA/branches, hydrocephalus	Cranial neuropathy, brainstem, or cerebellar injury	Cranial neuropathy, motor deficit	Facial weakness, hearing loss
Intraoperative
Anesthesia	General	General	General	General
Skin incision	Midline suboccipital from 2 cm above inion to C4	Linear from tip of mastoid to above line connecting zygoma	Linear	Curvilinear C
Bone opening	Bilateral suboccipital including foramen magnum, posterior arch of C1	Right suboccipital	Right suboccipital	Right suboccipital
Brain exposure	Bilateral cerebellar hemispheres/tonsils	Right lateral cerebellar, CPA	Right lateral cerebellar, CPA	Right lateral cerebellar, CPA
Method of resection	Semi-sitting position with precordial Doppler, midline incision, expose fascia, create Y-shaped muscle cuff based at superior nuchal line, midline incision through avascular plane, muscle retraction, suboccipital craniotomy including posterior lip of foramen magnum and C1 lamina, Y-shaped dural opening and retraction with sutures, drain CSF from cisterna magna, dissect tonsils, identify PICA and cerebellomedullary fissure, right tonsil peduncle identified and resected, open tela choroidea and inferior medullary velum to expose ventricular floor, partial resection of biventral lobule to expose lateral recess, incise MCP at superior and lateral portion of lateral recess above seventh/eighth nerve nuclei with stimulating, carful dissection of cavernoma with minimal mobilization of parenchyma and coagulation, spare DVA	Exposure of digastric groove/posterior mastoid/asterion; craniectomy up to transverse and sigmoid sinuses; curvilinear dural opening; arachnoid open for CSF relaxation; identification of cranial nerves starting with XI, then IX and X, and then VII and VIII, followed by V and then IV; exposure of lateral MCP surface, identify and open superior limb of cerebellopontine fissure with vein preservation, identify bulge on MCP and enter sharply, remove lesion with preservation of DVA, watertight dural closure	Right suboccipital craniotomy, exposure of CPA, dissection into CPA, identification of lateral MCP, corticectomy and resection if tracks are medial on DTI, telovelar if tracks are lateral to lesion.	Burr hole over asterion, craniotomy down to mastoid, drill some of mastoid, identify transverse and sigmoid sinus, open dura toward sigmoid sinus, release CSF from cisterna magna, identify cranial nerves VII–VIII and AICA, use surgical navigation and make corticectomy lateral to seventh/eighth nerve complex and AICA and remove lesion
Complication avoidance	Semi-sitting position, protect PICA, resect tonsil and biventral lobule to increase exposure, nerve stimulation to identify corridor, minimize parenchyma manipulation and bipolar cautery	DTI, sharp dissection, identification of anatomic landmarks	DTI, approach dictated by location of tracks	Identify cranial nerves VII and VIII and AICA, corticectomy lateral and away from complex
Postoperative
Admission	ICU	ICU	ICU	ICU
Postoperative complications feared	Cranial nerves V/VII/VIII deficit, motor/sensory deficit, CSF leak, hydrocephalus	Cranial neuropathies, CSF leak, hydrocephalus	Facial nerve dysfunction, motor deficit	Hearing loss, facial weakness, cerebellar dysfunction
Follow-up testing	MRI within 24 hours after surgery	MRI within 24 hours after surgery	MRI within 24 hours after surgery	MRI within 48 hours after surgery Audiogram 12 weeks after surgery
Follow-up visits	15 days after surgery 6 months after surgery	14 days after surgery 6 weeks after surgery	14 days after surgery 6 weeks after surgery	4–6 weeks after surgery