encephaloceles, meningocele, cranial dermal sinus tracts Flashcards
genetics of cranial DSTs
Cranial DSTs are generally thought to occur sporadically; however, a literature review of 82 cases revealed a female predominance, which may indicate a genetic basis. Similarly, Klippel-Feil anomaly, which can have a genetic component,70 has been associated with at least six reported cases
How do you approach occipital DSTs?
The standard approach for removing occipital DSTs involves the patient in prone position, where an elliptical incision is carried around the ostium of the lesion and blunt dissection is used to follow the tract down to its depth. Preoperative MRI is used to identify surrounding structures, such as the venous sinuses. In some cases, these lesions can extend deeply, even to the level of brain stem and the vein of Galen. If necessary, the craniectomy should be large enough to provide surgical access and the ability to maintain control of the intracranial component, in particular, the venous sinuses.5 The operative microscope may be useful, especially in dealing with tracts of smaller diameters.
Dermoid58 and epidermoid61 cysts can be found at any depth along the tract in up to ? % of cranial dermal sinuses
50
What is the most common error with dealing with cranial dermal sinus tracts?
Whenever possible, the cranial DST and associated dermoid or epidermoid cysts should be removed en bloc to mitigate against the risk of recurrence.60 The most common surgical error is leaving some capsule remnants behind that later lead to regrowth of the lesion.
how do you approach deeper nasal dermal sinus tracts?
In the deeper lesion, a craniotomy of the frontal and nasal bones with resection of the lesion up to the foramen cecum and crista galli will be necessary.71The craniotomy flap is replaced following resection and the nasal cartilages should be spared to avoid the complication of decreased nasal growth.71 Even in cases of active infection, we have found that a thorough irrigation and debridement of the site before replacing the bone flap is acceptable and has not placed the flap at risk.
How do you manage asymptomatic cranial DSTs?
For asymptomatic cranial DSTs, most authors agree that prophylactic surgical removal of the tract and any associated dermoid or epidermoid cyst is warranted “as soon as the child can tolerate the operation,”60 yet the exact timing of surgery for these asymptomatic patients remains a matter of debate.
in an otherwise healthy child, we would typically schedule an elective surgical time at 5 to 8 months of age
Say you suspect a cranial dermal sinus tract but you don’t see anything on MRI, what do you do?
When a cranial DST is suspected but MRI fails to demonstrate a tract, surgical exploration of the dimple and surrounding tissues is still advised
when do you explore cranial dermal sinus tract on a faster time scale?
In the presence of:
CSF leak
infection
or raised intracranial pressure,
surgery should be performed emergently.
what percentage of nasal DSTs terminate in cribriform plate, the dura, and even extending into the brain?
Most nasal DSTs terminate in the deep structures of the nasal cavity with up to 45% involving the cribriform plate, the dura, and even extending into the brain
what is recurrence risk of dermoids? (cranial)
When completely resected, cranial DSTs rarely recur, and the prognosis is usually favorable; however, recurrence following partial removal has been documented as late as 20 years from the original operation.73 Moreover, there are reports of patients with hydrocephalus that did not abate after resection of the intracranial dermoid or abscess and that ultimately required permanent CSF shunting
what are complications of dermoid and epidermoid cysts?
These lesions can be sources of mass effect or can themselves become secondarily infected60 and lead to the formation of contiguous abscesses within the scalp, below the dura, or within brain.61,62,32 In addition, the cysts can rupture spontaneously and cause an aseptic (or Mollaret’s) meningitis,5,66 or they obstruct CSF pathways, leading to hydrocephalus requiring emergency ventriculostomy
