Indications and Techniques for Cranial Decompression after Traumatic Brain Injury

Youmans Chapter 338Sharon Webb

Shelly D. Timmons

Outline

• Background• Indications• Technique• Complication

Background• Neolithic time• 1880 Bergman• 18xx Cushing : subtemporal decompressive craniectomy for control ICP• Decompressive craniotomy or craniectomy(DC)

improved result• Nontrauma

– Uncontrolled ICP after aneurysm subarachnoid hemorrhage– Signs of cerebral edema during aneurysm clipping– increased ICP and epidural, subdural, or intracerebral

hematoma after aneurysm surgery– cerebral edema and elevated ICP without radiologic evidence of

cerebral infarction after aneurysm surgery

Background• Nontrauma

– Cerebral edema after cerebral infarction : compromise of CPP, oxygenation , metabolism, transtentorial herniation

• Clinical trials of drugs and other treatment modalities : DC has advantages over other neuroprotective therapies in that it has a global action, fewer systemic side effects• Therapeutic approaches for decreasing ICP

• reduction of the volume of intracranial contents (blood, brain, or CSF)

• reduction of cerebral metabolic demands• increase in cranial volume via DC

Indication• Poor candidate for DC

– Glasgow Coma Scale (GCS) score of 3– brainstem injury– central herniation

• Motor score is the most important factor to consider in patient selection

• The presence of midline shift on computed tomography (CT) of the brain is highly predictive prognostically : The degree of shift is inversely related to outcome, and elevated ICP is presumed.

Indication• Absent or compressed cisterns are also predictive of

elevated ICP and a poor outcome• Timing of surgery

– Early decompression (within 4 hours of injury) results in profound decreases in mortality and improvement in functional outcome at 6 months

Indication• Decompressive surgery should be considered very shortly

after failure of maximal medical therapy to control ICP– head to 30 degrees– use of sedation with or without paralytics– maintain Paco2 at 30 to 35 mm Hg– maintenance of normothermia– maintenance of hyperosmolar euvolemia (with the administration

of mannitol and hypertonic saline)– avoidance of hyperglycemia– support of CPP with volume or pressors– drainage of CSF

Technique• Conjunction with evacuation of an extra-axial mass• Conjunction with removal of an intraparenchymal

hemorrhage• Conjunction with lobectomy• Diffuse brain edema• For penetrating trauma with debridement of bone

fragment• Open depress comminuted skull fracture with underlying

brain injury

Technique• Bifrontal or unilateral hemicraniectomy ?• diffuse brain edema with no mass lesion or midline shift,

nondominant hemisphere unilateral or bifrontal DC• the side with the greater lesion volume or cerebral

edema is chosen for unilateral decompression

Technique• Comatose status precludes clearance of c-spine injury

--> neutral position• Reverse trendelenburg position for head elevation• Sandbag or shoulder roll ipsilateral shoulder• Doughnut rather than Mayfield headrest• Hair clipping just across midline and far as posterior as

possible• Hemicranium was prepared, marked, and injected with

1% lidocaine for hemostasis

Technique• Standard large question

mark flap or reverse question mark incision

• Tragus – above auricle – parieto-occipital – frontal

• Raney clip for scalp bleed• Bovie cautery for temporalris

fascia and muscle• Secure flap with fish hooks • Epinephrine soaked

laparotomy sponge is used on galeal surface

Unilateral DC • Lateral : superior saggital sinus• Frontal : mid pupillary line• Inferior : floor of the temporal• Posterior : parieto – occipital

area

Bifrontal DC• Anterior cranial fossa floor to

coronal suture posterior• Temporal fossa floor bilaterally

Technique• avoid aggressive débridement of contusions to preserve

potentially viable tissue, particularly in the posterior temporal lobe

• Duraplasty over such contusions allows preservation of cerebral tissue and edema without compression

• Epidural hematoma requires leaving the bone flap out much less often than subdural hematoma does because of the relative lack of underlying brain injury with the former.

Massive open wound to the cranium

• Incorporate laceration or entrance wound• Preserve vascular supply• Extensive debridement of necrotic tissue• If multiple bone fragment small one discard

Durotomy

• Akin to fasciotomy• Unilateral operation C-shaped c dural base along frontal

fossa floor• Bifrontal operation ligation and division of the anterior

saggital sinus• Whatever the dural opening technique, it is imperative that the

temporal dura be opened to decompress the temporal lobe or lobes.

Duraplasty• Autograft or allograft• fascia lata, pericranium, bovine pericardium, collagen

matrix products, and synthetic dural substitutes• Restore more normal CSF circulation• Prevent hygroma or CSF leak form the wound

Vascular tunneling technique• alleviate venous congestion (and therefore evolution of

brain edema)• small supporting pillars made of hemostatic sponge are

placed around the superficial vessels supplying the protruding portion of the brain

• preventing them from being compressed by the pressure between the dural edge and the brain tissue

Partial or anatomic lobectomies• in conjunction with DC for intractable intracranial

hypertension• Less significant when DC performed early after meical

management failure• limited to the frontal and anterior temporal lobes• Reserve for

– “pulped” or necrotic lobe with malignant cerebral edema at surgery(increase cerebral blood volume from loss of cerebral vascular autoregulation)

– pulselessness of the hemisphere– vessel occlusion or infarction – profound coagulopathy in the face of multiple intracranial

hemorrhages

Bone flap• Store in abdominal subcutaneous or tissue bank• Resorption,rhabdomyolysis, infection• Clear of hematoma, irrigate with antibiotics• Synthetic implant in case of bone flap infection or

resorption• PEEK(polyetheretherketone), porous polyethylene,

acrylic or titanium

Bone flap replacement• 4 wks up to 12 Months. About 3 month• Helmet for patient,removed when the patient go to bed• Longer interval

– scalp contraction wound dehiscence– temporalis atrophy temporomandibular joint complaints and

cosmetic asymmetry– development of the syndrome of the trephine (which can cause

severe headache• CT brain before replacement : identification of

hydrocephalus or subdural or subgaleal fluid collections, delinate degree of temporalis muscle atrophy

Reimplantation surgery• Meticulous wide sterile preparation on the scalp incision• Perioperative antibiotic• Previous incision• Avoid heat to the underlying brain fron monopolar

cautery• Avoid pressure on the brain from digital dissection or

traction on the cutaneous flap• Replace bone flap with standard cranium miniplating

system

Complication• Hygroma(26%)

– Ipsilateral side– Resolve spontaneously without intervention : observation alone– isolated or serial lumbar puncture, temporary continuous lumbar

drainage, lumboperitoneal shunting, or ventriculoperitoneal shunting

– Frequently, replacement of the bone flap will lead to resolution of the hygromas.

Complication• Hydrocephalus(14-29%)

– Fide hydrocephalus must be distinguished from hydrocephalus ex vacuo• Elevated pressure on 1 or more LPs• Papilledema on fundoscopic exam• Symptom of headache/pressure• Finding of transependymal absorption on CT or T2WI MRI• +- patient’s neurologic recovery seem worse than expected

– Tunnel ventriculostomy with external drainage– Lumbar drainage if the cistern are open– Bone flap replacement and shunting

Complication• Wound infection

– extensive scalp incisions– subgaleal fluid accumulations– lengthy hospitalizations– colonization with nosocomial and resistant bacteria– invasive supportive procedures such as tracheostomies, central

lines, and bladder catheterizations– frequent comorbid conditions of lung injury and pneumonia,

intra-abdominal injuries, and orthopedic injuries– Fever evalutation with CSF, CBC , CRP

Complication• Wound dehiscence without infection

– thin areas of scalp, such as women, the malnourished, those with lacerations or abrasions, and those with chronic wounds with retracted skin and sunken flaps

• Bone flap resorption– Contaminated bone– Abdominal bone flap storage

• Seizure– Acute and chronic phase– Medical treatment for 7 days

Complication• Syndrome of the trephine

– Headache, dizziness, mood change, seizure– Cerebral edema resolve sunken flap– Recumbency or replace bone flap

• hydrocephalus