Giant Occipital Encephalocele - Challenges in Management.

INTRODUCTION: Giant occipital encephalocele (GOE) is a term used when the size of the OE is greater than or equal to the size of the head. It has been limited to case reports, with only sporadic exclusive series. This is a series of GOE managed at our center over time with emphasis on practical problems faced in management.
MATERIALS AND METHODS: This was a retrospective observational study. The patients were evaluated for the age of presentation, sex, and head size. Any associated neural tube defect was also looked for. Imaging was used for associated brain anomalies and to plan the surgical procedure. The requirement of ventriculoperitoneal (VP) shunt was also assessed.
RESULTS: During the study period of 7 years, 11 patients of GOE were admitted. Apart from one, all other patients were <1 year of age. Nine patients underwent surgical intervention, which included excision and repair of swelling with or without VP shunt placement. The content of the sac was only cerebrospinal fluid (CSF) in six patients and CSF and gliotic brain tissue in remaining patients. The attendants of two patients did not give consent for surgery and left against medical advice.
CONCLUSION: GOE is an uncommon entity with limited information about management. Careful evaluation, proper imaging of patient, and care during intraoperative and postoperative periods with emphasis of factors determining the prognosis may provide satisfactory results. Copyright:

INTRODUCTION

The encephalocele is a condition characterized by the protrusion of the intracranial contents through a bone defect of the skull.[1] The incidence of encephalocele is 1/5000 live birth.[2] The common presentation of encephalocele is an occipital encephalocele (OE). The size of encephalocele may vary from small to large masses. It may be occipital or frontal encephalocele. Nearly 15% to 20% of children have additional congenital anomalies, including neural tube defects.[234] Giant OE (GOE) is a term used when the size of the OE is greater than or equal to the size of the head.[5]

Although OE has been described adequately in the literature, GOE has been limited to case reports, with only sporadic exclusive series.[67] We are presenting our series of GOE managed at our center over time with an emphasis on practical problems faced in its management.

MATERIALS AND METHODS

This was a retrospective observational study conducted in the department of pediatric surgery of the medical university from January 2010 to December 2016. All patients of GOE were included in this study. The patients were evaluated for the age of presentation, sex, and head size. Any associated neural tube defect was also looked for. Patients were evaluated by a computed tomography (CT) scan or magnetic resonance imaging (MRI) or both for associated brain anomalies and to plan the surgical procedure [Figure 1].

Figure 1

Computed tomography scan showing giant encephalocele with brain matter as content

After evaluation, patients underwent excision of the encephalocele. The operative procedure included dissection of the pedicle, careful drainage of the cerebrospinal fluid (CSF), excision of the gliotic brain tissue, and closure of the defect. The management protocol of GOE is depicted in Figure 2. The requirement of a ventriculoperitoneal (VP) shunt was based on ventricular/biparietal ratio on CT/MRI basis.[8] On its basis, if there was severe hydrocephalus, VP shunting was performed before the excision of encephalocele. If it was mild or moderate hydrocephalus, excision was performed, followed by observation. Repeat scan in nonshunted group was performed at 1-, 3-, and 6-month follow-up. In case of progression to severe hydrocephalus, VP shunting was performed. In case of nonprogression, patients were followed up at 6 monthly period or if any problem was faced by the attendants. After shunting, patients were evaluated by CT/MRI scan at 3, 12, and 24 months. Clinical efficiency of the shunt system was checked at every visit by manual pumping of the chamber.

Figure 2

Management algorithm of patients of giant occipital encephalocele. CT – Computed tomography, MRI – Magnetic resonance imaging, VP shunt – Ventriculoperitoneal shunt, OPD – Outpatient department

In case of skin infection or ulceration of the encephalocele, patients were administered intravenous antibiotics covering both Gram-positive and Gram-negative organisms. Local cleaning and application of topical antibiotics cream were used for wound healing.

The follow-up was made on outpatient basis. Telephonic conversation with parents was used in case of delayed visit to the outpatient department Patients were called at 1 month interval for the first 6 months or early if there was evidence of any problem by attendants.

RESULTS

During the study period of 7 years, 11 patients of GOE were admitted in our department [Table 1]. Apart from one patient of 4 years of age, all other patients were <1 year of age. Among them, eight patients were male and the remaining three were female. Of nine patients who underwent surgery, excision and repair of GOE were performed as primary surgery in seven patients. Of those seven patients, two patients underwent VP shunt placement after excision due to raised intra-cranial pressure (ICP). VP shunt was placed as initial surgery in two patients, which was followed by excision and repair after about 2 months. Those patients who underwent VP shunt placement as primary surgery showed a decrease in the size of the encephalocele. The content of the sac was only CSF in six patients and CSF and gliotic brain tissue in remaining patients. The attendants of two patients did not give consent for surgery and left against medical advice.

Table 1

Patients of giant occipital encephalocele

n	Age/sex	CT/MRI	Surgery	Outcome	Associated findings	Long-term follow- up
1.	4 months/male	CT	VP shunt. Excision after 2 months. VH ratio 0.41	Uneventful	Chiari malformation, corpus callosal agenesis, cyanotic heart disease	Expired after 4 months due to pneumonitis
2.	5 months/male	CT	Excision	Developed meningitis in postoperative period, managed with IV antibiotics	No hydrocephalus	Delayed milestones, mental retardation
3.	4 years/female	CT	Excision	Uneventful	Delayed milestones, Anemia	6-month follow-up, doing well
4.	1 month/male	CT	Excision. VP shunt after 5 days. VH ratio 0.38	Postoperative ventilator after VP Shunt	Chiari malformation	Delayed milestones, mental retardation
5.	1 month/female	CT	Excision. VP shunt after 7 days. VH ratio 0.38	Expired after 15 days due to severe pneumonitis	Microcephaly, hydrocephalus, congenital heart disease	Expired after 15 days due to pneumonitis
6.	3 months/male	CT	Excision	Uneventful	CM, skin necrosis between GE and skull	Follow-up of 2 years
7.	5 months/female	MRI	VP Shunt. Excision after 2 months. VH ratio 0.4	Uneventful	Chiari malformation	Follow-up of 4 years
8.	8 months/male	CT	Excision	Postoperative ventilator due to hypothermia and dyselectrolytemia, extubated after 3 days	Hydrocephalus and skin necrosis	2-year follow-up doing well
9.	1 month/male	CT	Excision	Postoperative ventilator extubated after 2 days	Microcephaly, hydrocephalus, congenital heart disease	Expired after 2 months cause?
10.	1 month/female	MRI	-	-	Microcephaly, skin necrosis at pressure points	LAMA
11.	1 day/female	-	-	-	Ruptured sac with CSF leak	LAMA

CT: Computerized tomography, MRI: Magnetic resonance imaging, VP shunt: Ventriculoperitoneal shunt, LAMA: Left against medical advice, CSF: Cerebrospinal fluid, IV: Intravenous, VH ratio: Ventricular/hemispheric ratio. Delayed milestones and mental retardation were evaluated in pediatrics department. It included standard clinical features such as neck holding, ability to sit with and without support, delayed walking with and without support.

Associated cranial malformations included microcephaly, Chiari malformation, corpus callosal agenesis, and hydrocephalus [Table 1]. Hydrocephalus was symmetrical in all of them. Skin necrosis at pressure points and rupture of the sac with leaking CSF was also noticed in this series [Figure 3a and b]. Three patients expired in the follow-up. The exact cause of mortality could not be ascertained in one patient, while the remaining two developed pneumonitis. The probable reason may be the associated congenital heart disease.

Figure 3

(a) Pressure changes in a giant occipital encephalocele. (b) Ruptured encephalocele

Of four patients, who underwent VP shunt placement, two expired within 4 months due to other problems [Table 1]. The remaining two patients did not have any specific shunt-related complications.

DISCUSSION

Encephalocele, a form of neural tube defect, accounts for 10%–20% of all dysraphism.[9] Giant encephalocele poses a challenge due to the amount of neural tissue which is content of sac, size of the sac, blood loss, and hypothermia. OEs are common in the Western Hemisphere, whereas the frontoethmoidal varieties are frequently seen in South and Southeast Asia.[9] It has been observed that frontal encephaloceles are more common in males, while 70% of posterior or OEs occur in females.[10] However, in our series, 70% of patients were male. There may be other anomalies associated with GOE such as hydrocephalus, Dandy–Walker cyst, Chiari malformation, craniosynostosis, and microcephaly.[67911]

It is obvious from Table 1 that many patients presented after the neonatal period. When enquired for this late presentation, the reasons cited were poor referral and cost factors, which prevented early referral. Cost factor becomes an important concern in the catchment area of our center. Clinically, there is a huge cystic swelling on the back of the head, which acts as a serious health concern to the attendants. Because of the large occipital swelling, neonatal transportation is a difficult task. We have seen some intelligent attendants who had brought the neonate in a large tray so as to avoiding the possibility of rupture of sac [Figure 4]. Larger size is a risk factor for sac rupture, which was noticed in two patients of this series. Rupture may predispose the patient to meningitis; hence, prophylactic antibiotics become important life-saving measure. Besides, pressure ulcers may also occur. The same was noted in two patients. These pressure ulcers may need some early treatment for preventing the skin infection. However, in case of GOE excision, extensive treatment may not be needed. The idea is to decrease the possibility of postoperative infection of the incision site or brain. An uncommon but important cause of skin necrosis can be torsion of the pedicle of encephalocele.[12] The torsion of the pedicle is not commonly mentioned; however, the first-hand knowledge of this entity may help to avoid its occurrence.

Figure 4

Transportation of neonate in a tray

CT scan of the head is useful as it is quick to perform, less costly, and easily available. Besides, it may be able to delineate the size of the bony defect.[6] However, MRI is an optimal investigation to visualize the contents of the sac and its relationship to the venous sinuses.[1013] Sometimes, the sagittal sinus, torcular, and the transverse sinus are in the vicinity of the sac. These can be evaluated before surgical intervention with the help of imaging modalities.[14]

Endotracheal intubation is an important concern in these patients. Special precaution is needed to prevent any compression and rupture of the sac; hence, the child cannot be positioned supine and needs lateral position for intubation. As described in a few series, a position by placing the baby at the end of the table with hyperextended neck may be useful for intubation. Preoperative aspiration of CSF from the encephalocele sac for easy intubation has been suggested.[714] Other perioperative problems are serum electrolyte imbalance which may occur during draining of CSF, hypothermia, and blood loss.[1013] Besides this, there may be cardiovascular problems such as cardiac arrest, tachycardia or bradycardia, and hypotension. Respiratory complications such as hypoxia, hypercarbia, or endobronchial intubation have also been reported.[7] Inhalational anesthesia has been suggested as a preferred mode as it can be washed off quickly. Our anesthetists were able to intubate patients in lateral position.

The strategy of surgical intervention in GOE depends on various factors such as the amount of neural tissue in the sac, state of CSF pathway, neurological status of the patient, and the presence or absence of associated congenital anomalies elsewhere in the body.[1114] Fortunately for us, most of our patients had only CSF as a content of the GOE. Besides this, there may be gliotic brain tissue, which may be excised without any specific neurological deficit.[10] Factors well known to determine the prognosis of patients diagnosed with OEs include the size of the sac, neural tissue content, hydrocephaly, infection, and pathologies that accompany this condition.[10]

CONCLUSION

GOE is an uncommon entity with limited information about management. Careful evaluation, proper imaging of patient, and care during intraoperative and postoperative periods with the emphasis of factors determining the prognosis may provide satisfactory results.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.