The meningeal membrane covering the giant encephalocele is either covered by a normal, dysplastic or a thin membrane. Clinically, the presentation of giant occipital encephaloceles is evident due to their characteristic swelling.[2] The contents of occipital encephalocele mainly include meninges and occipital lobes. It may also comprise of ventricles, cerebellum, and brain stem. The factors influencing the outcome in the occipital encephalocele patients are site, size and herniation of the brain into the sac. Site, size, and the amount of brain herniated inside the sac determines the prognosis. The presence of brainstem or occipital lobe with or without the dural sinuses in the sac along with hydrocephalus also influence the outcome of the case.[4]
The large-sized swellings may possibly have a remarkable brain herniation, an abnormality of the underlying brain and microcephaly. The clinical examination comprises the examination of its size, extent, amount of protrusion and its location along with the size of bony defect.[2] The size of the head holds a significance importance for clinical suspicion of microcephaly or hydrocephalus and extracranial anomalies.[2] MRI brain is the usual investigation of choice along with the three dimensional Computed Tomography (CT) that further helps in evaluating the deformity and hence the surgical procedure can take place as soon as possible to avoid further neurological deficits.[5]
Giant encephaloceles are rare; surgical procedures are a challenging task for the anesthesiologists, as well as the neurosurgeons. The challenges present are mainly due to its complicated site, enormous size, associated bulging contents resulting in intracranial anomalies, intraoperative blood loss, and prolonged anesthesia.[6] The major aim of the anesthesiologist is to avoid the premature rupture of the encephalocele intraoperatively. The occipital site of the encephalocele causes a hindrance with the intubation as due to a difficult airway caused by the restriction of the neck movement. This further leads to an inability of having an optimal tracheal intubation position.[3]
The operative procedure also includes the management of possible loss of large quantities of CSF causing superimposed electrolyte imbalance. Infants with encephalocele can develop sudden hypothermia due to dysfunction of autonomic control below the present defect.[3] Thus immediate consideration and management has to be given to hypothermia, blood loss, and its associated complications. The surgery is advised to be done as soon as possible to avoid life threatening complications such as Central Nervous System (CNS) infections, respiratory distress, aspiration pneumonia, irreversible impairment of vagus nerve and hypothermia.[5]
The table below, comprises all the reported cases to the author's knowledge. (Table 1)[3, 4, 9–21] The main aim is to portray the different and most commonly used surgical procedures in the management of giant occipital encephaloceles. The most frequently used method is simple resection and dural repair. Expansion Cranioplasty is one of the surgical procedures that consists of a mesh to provide room for the protruded sac. Another technique used is done through ventricular volume reduction. It is a two-step technique; for start it increases the ventricular pressure inducing hydrocephalus followed by a ventriculoperitoneal shunt. The ventricles then contract and the protruded tissue repositions itself inside the cranium. For the herniated cerebellar and occipital parenchyma, an incision is made in the tentorium to create an infratentorial area for the herniated tissue to retract.[7]
Table 1
CaseNo.
|
Year
|
Age
|
Site
|
Associated Findings
|
Surgery
|
1[18]
|
2002
|
26 days
|
Occipital
|
No brain tissue in the sac, hydrocephalus
|
Excision; 2nd surgery; VP shunt
|
2[18]
|
2002
|
3 months
|
Occipital
|
Hydrocephalus
|
VP shunt; Surgical excision and repair.
|
3[18]
|
2003
|
10 days
|
Occipital
|
No associated findings
|
Surgical excision and repair.
|
4[18]
|
2003
|
9 months
|
Occipital
|
Polygyria; microgyria; craniostenosis
|
Surgical excision and repair; craniotomy; cranioplasty by autologous bone.
|
5[18]
|
2004
|
2 ½ months
|
Occipital
|
Hydrocephalus
|
VP shunt; Surgical excision and repair.
|
6[18]
|
2005
|
4 months
|
Occipital
|
Hydrocephalus; craniostenosis
|
Surgical excision and repair; craniectomy
|
7[18]
|
2005
|
5 months
|
Occipital
|
Hydrocephalus; craniostenosis
|
Surgical excision and repair; craniectomy and cranioplasty
|
8[18]
|
2006
|
3 months
|
Occipital
|
No hydrocephalus; craniostenosis
|
Craniectomy; excision; cranioplasty by methyl methacrylate
|
9[18]
|
2007
|
1 month
|
Occipital
|
Hydrocephalus
|
VP shunt; Surgical excision and repair.
|
10[18]
|
2008
|
1 year
|
Occipital
|
Hydrocephalus
|
Surgical excision and repair. VP shunt 4th day
|
11[18]
|
2008
|
4 years
|
Occipital
|
No associated findings
|
Repair of encephalocele
|
12[18]
|
2009
|
4 months
|
Occipital
|
Microcephaly; craniostenosis; small bony defect
|
Surgical excision and repair; craniectomy
|
13[18]
|
2009
|
20 days
|
Occipital
|
Microcephaly
|
Surgical excision and repair; patient had intraoperative hypothermia
|
14[12]
|
2010
|
4 months
|
Occipital
|
No associated findings
|
Sac was opened. The herniated brain tissue looked redundant. The sac was reduced in size, sufficient enough to accommodate the healthy-looking brain tissue. The skin was closed with interrupted sutures.
|
15[4]
|
2014
|
14 days
|
Occipital
|
History of limb weakness. There was no bladder and bowel dysfunction.
|
Under general anesthesia with prone position excision and repair of sac was done.
|
16[3]
|
2014
|
1 month
|
Occipital
|
No associated findings
|
The dysplastic portion of the occipital lobe was removed, and tight dural closure was achieved in two layers.
|
17[11]
|
2014
|
6 day
|
Occipital
|
Delayed cry at birth, hypotonic with decreased spontaneous movements and had respiratory distress.
|
Dysplastic cerebellar tissue with a herniated sac was excised, and the primary closure of the defect was performed.
|
18[17]
|
2016
|
7 months
|
Occipital
|
Craniosynostosis
|
Excision and repair of sac with strip craniectomy of sagittal and lambdoid suture.
|
19[15]
|
2016
|
40 days
|
Occipital
|
Persistent elevation of serum potassium levels
|
The child underwent complete surgical excision and repair of the meningoencephalocele.
|
20[20]
|
2016
|
<1 month
|
Occipital
|
Posterior cerebellar artery and basilar artery into the defect
|
Excision and Repair
|
21-22 [20]
|
2016
|
<1 month
|
Occipital
|
No associated findings
|
Excision and Repair
|
23[20]
|
2016
|
<1 month
|
Occipital
|
No brain tissue inside the sac, hydrocephalus
|
Excision and Repair
|
24[13]
|
2017
|
2 months
|
Occipital
|
No associated findings
|
A circumferential incision was given on the swelling with meticulous dissection. The protruded portion of cerebellum was excised, and the dural closure was done.
|
25[16]
|
2017
|
1 day
|
Occipital
|
No associated findings
|
The sac with dysplastic brain tissue was excised and closed in a single layer using continuous suture.
|
26[16]
|
2017
|
1 month
|
Occipital
|
No associated findings
|
The sac was dissected out and the dysplastic brain tissue was excised. The sac was closed in a single layer using continuous suture, skin and subcutaneous tissue was closed.
|
27-55 [19]
|
2017
|
5 months (average)
|
Occipital
|
Hydrocephalus (19 cases) and delayed milestones (17 cases)
|
Excision and Repair
|
56[21]
|
2018
|
1 day
|
Occipital
|
No associated findings
|
No associated findings.
|
57[14]
|
2019
|
4 months
|
Occipital
|
No associated findings
|
The encephalocele was excised and the dura was identified, and a watertight closure was carried out.
|
58[9]
|
2019
|
6 months
|
Occipital
|
Delayed motor milestones in the form of inability to hold her head
|
Excision of the redundant neural tissue, and closure of the dura done and skin was reconstructed.
|
59[10]
|
2019
|
10th day
|
Occipital
|
No associated findings
|
A transverse incision was given
over the parietal mass followed by surgical excision and repair.
|
60[6]
|
2019
|
3 months
|
Occipital
|
The child had a delayed milestone with poor feeding and absent neck holding. ECHO showed presence of a small 5 mm ASD with L→R shunt
|
Posterior paramedian incision was given, encephalocele sac along with some brain tissue was excised followed by primary duraplasty.
|
Modern day neurosurgical techniques along with neuroimaging and neonatal intensive care with neurological facilities have greatly improved morbidity and mortality rate in the management of encephaloceles.[8] Postoperatively, complications such as hypothermia, raised intracranial pressure (ICP), apnea, cardiac arrest, CSF leak, and infection can arise and hence need to be managed effectively. However, in our case no complications were present. Alongside all present difficulties, intubation and anaesthetic management in our patient were successfully achieved.