The peritoneal cavity is widely used as the destination of choice for cerebrospinal
fluid (CSF) shunts. Various alternative distal sites have been used, particularly
in the presence of certain contraindications, which include the cardiac atria, for
ventriculoatrial (VA) shunt, or the pleural cavity for ventriculopleural (VPL) shunt.[1] Each procedure is associated with its own set of complications and the choice of
selection of the distal site of CSF drainage is often based on surgeon's preference
along with patient's factors.[2] While the historical literature describes pleural effusion and pneumothorax as complications
of a VPL shunt, there is paucity of data justifying the application of one technique
over the other. We report a rare case of postoperative pneumothorax in a case of VPL
shunt being further complicated by pneumocephalus.
A 41-year-old gentleman, who is a known case of operated grade II tectal plate glioma
with hydrocephalus for which resection of glioma and ventriculoperitoneal (VP) shunt
placement was done 25 years ago, presented with complaints of persistent watery discharge
from abdominal site scar with abdominal distension and memory disturbances. Patient
also had history of VP shunt revision done 20 years ago. After further workup, the
diagnosis of Koch's abdomen with tubercular ascites with VP shunt malfunction was
made. Since the patient had no neurological complaints, the shunt assembly was removed
and antitubercular therapy was started.
The patient was readmitted with complaints of headache after 2 weeks. Non Contrast
CT (NCCT) brain was done that was suggestive of hydrocephalus. In view of abdomen
being unfavorable due to tubercular ascites, right-sided programmable VPL shunt with
antisiphon device was done. On the first postoperative day, patient was clinically
normal. The postoperative computed tomographic (CT) scan brain revealed pneumocephalus
and pneumoventricle involving both the lateral and third ventricles. The next day
patient had deterioration in the neurological status. On examination, the Glasgow
Coma Scale was E2V2M5 with development of subcutaneous emphysema over the thorax.
However, there was no respiratory distress. Patient was intubated and put on mechanical
ventilation. Fresh CT scan brain revealed increase in the ventricular dilatation and
pneumoventricles ([Fig. 1]). CT thorax was also done simultaneously, which revealed right hydropneumothorax,
pneumomediastinum, and subcutaneous emphysema on the right side ([Fig. 1]). Cardiothoracic surgery consult for CT thorax findings was done and right-sided
intercostal drainage (ICD) tube was inserted. The patient was then taken up for surgery
and right frontal external ventricular drainage (EVD) with Ommaya insertion was performed.
Taking care to remove any air column in the distal shunt tube and after confirmation
of adequate distal flow, the ligation of pleural end of VPL shunt was done. CSF examination
was normal and the cultures were sterile. There was improvement in the neurological
status the next postoperative day and patient was extubated. The patient was conscious,
oriented with no focal neurological deficits. Postoperative CT scan brain showed decrease
in the air column in ventricles with subsequent resolution of pneumoventricles in
the follow-up repeat scans ([Fig. 2]). The repeat CT thorax on 3rd postoperative day revealed resolution of pneumothorax
following which the ICD was removed ([Fig. 2]). On 6th postoperative day, the EVD was removed and the ligated pleural end of shunt
tube was reopened. The patient was discharged in a stable condition and is now under
follow-up.
Fig. 1 Computed tomographic (CT) scan brain showing pneumocephalus (thin arrow) and pneumoventricle
(thick arrow). Shunt tube is seen in situ. CT thorax showing right pneumothorax (thick
arrow) with subcutaneous emphysematous changes (thin arrow). Pleural end of shunt
tube can be seen at 10'o clock position in right hemithorax.
Fig. 2 Postexternal ventricular drainage insertion computed tomographic (CT) scan showing
complete resolution of pneumocephalus and postintercostal drainage insertion CT thorax
showing complete resolution of pneumothorax.
VPL and VA shunts are an alternative option to the VP shunt, when the peritoneum is
unsuitable due to abdominal pathology, abdominal adhesions, or recurrent complications
with abdominal distal tubing. The VPL shunts serve as safe and feasible second-line
option of utility for CSF diversion.[2]
[3] While they are associated with the complications like pleural effusions, over drainage,
and pneumothorax, there is, theoretically, greater potential for severe complication
following VA shunt placement, including shunt nephritis (3.5–11%), injury to major
vessels, cardiac thrombi, and endocarditis. Moreover, since the surgeon's preference
is a taken into account in selecting a particular approach, the decision for a VPL
shunt was taken in this case.[2] Since the patient had memory impairment, endoscopic third ventriculostomy (ETV)
was not done in this case owing to few reports of post-ETV persistent cognitive inefficiencies
in some cases.[4] The incidence of distal complications in VPL shunts is 10 to 20%, most common being
pleural effusion and pneumothorax.[1] The probable reason for the development of pneumothorax in the present case was
inadvertent injury to the visceral pleura at time of insertion of distal end of shunt
tube. Haret et al have reported development of pneumothorax and subcutaneous emphysema
in two cases of VPL shunts.[5] The occurrence of subcutaneous emphysema in our case could be due to air migration
via the surgical approach into the subcutaneous tissue, easier subcutaneous plane
dissection by air due to recent shunt removal surgery, and non-re-establishment of
normal negative intrapleural pressure relationship. The problem of overdrainage can
be addressed with the use of shunt catheters with antisiphon valve mechanism as done
in this case.[2]
[5] The pneumothorax usually resolves and responds well to insertion of an ICD tube
that was performed in our case.
Tension pneumocephalus is defined as the presence of air in the intracranial space
that can be due to neurosurgical procedures, skull base fractures, sinus fractures,
and congenital skull defects. However, symptomatic tension intraventricular pneumocephalus
complicating pneumothorax post-shunt surgery is of rare occurrence; and the studies
in literature regarding this are sparse. Sharifabad et al reported a case of pneumocephalus
post-pneumothorax in a patient with VPL shunt surgery that was managed by a shunt
revision.[6] The probable mechanism of development of concomitant subcutaneous emphysema and
pneumoventricle in our case could be intracranial air migration through shunt catheter
along with peri catheter subcutaneous dissection by air column. However, the exact
cause could not be identified in the present case.
The possible steps to avoid such complications at time of distal catheter insertion
are taking a “figure of 8” suture in the intercostals muscle to allow careful sealing,
deflation of the ipsilateral lung by the anesthetist, and avoidance of nitrous oxide
during the procedure.[1]
[7] In our case, the tension pneumocephalus was managed by EVD that was kept patent
along with temporary ligation of distal shunt tube until the resolution of pneumothorax;
and the patient responded well to the given management.
Conclusion
Tension pneumocephalus complicating pneumothorax is a rare but not an unreported complication
of VPL shunt surgery. However, a careful and meticulous surgical technique particularly
at distal shunt catheter end, anticipation of such complications with timely diagnosis,
and management are imperative for a better patient outcome.
