Case of penetrating brain injury caused by a ventriculoperitoneal shunting procedure

Discussion

To the best of our knowledge, there are no reports describing penetrating brain injury caused by shunt tunnellers in the literature. One reason for this could be that the surgeons involved in such accidents may have chosen to not report it because of the negative implications. We considered that it is necessary to describe the cause of this event as one of the complications of VP shunting. Treatment for penetrating brain injury includes evacuation of haematoma, antiseizure prophylaxis and surgical correction for cerebrospinal fluid leak.2 Based on the guideline for the management of penetrating brain injury,3 the patient in this case needed no further treatment.

The primary cause of this rare complication was the need to perform VP shunting on the same side as the biopsy of the brainstem tumour. For the biopsy, the left side was selected since, in order to perform a minimally invasive biopsy would necessitate tumour removal from the left side, where the tumour was exophytic. She had a pacemaker embedded under the chest subcutaneously on the right side, making it impossible to place the shunting system on her right side. Thus, we had to select the same side with craniotomy.

The bone defects after lateral suboccipital craniotomy at the time of biopsy were fixed with titanium plates and autologous bone. The bone gap after cranioplasty was approximately 1 cm. The CT images obtained during and after VP shunting did not show any changes in the cranioplasty, so we believe that the shunt tunnellers may have accidentally passed through this gap. MRI showed contusion of the cerebellar hemisphere just inside the bone gap. We concluded that this finding supported our hypothesis of the invasion route into the skull with a shunt tunneller. Considering these facts, it is difficult to avoid this penetrating trauma with the minimised bone gap by cranioplasty. We concluded that the creation of subcutaneous tunnels should be performed in a route that greatly bypasses craniotomy. Alternative method to avoid penetrating brain injury is making tunnel from cranial to caudal. There is no evidence that the direction of tunnelling affects complication. Tunneller direction should be carefully considered in the patient who had craniotomy.

Although the procedure of making subcutaneous tunnels with a shunt tunneller is quite old, it is regarded as a simple and safe technique. However, some reports have described lung injuries caused by the migration of the shunt tunneller. Hattammaru et al reported pneumothorax due to shunt tunneller injury during VP shunt placement. The pneumothorax was detected before extubation because of an increase in airway pressure and a reduction in oxygen saturation to 70%, after which a chest drainage tube was inserted.4 Kono et al reviewed the literature on pneumothorax after VP shunt placement and noted that all five cases involved female patients. They suggested that female sex or obesity may be associated with complications.5 Our patient had a thin body type but was a woman. In addition, she showed no variations in vital signs during the surgery, and her complications were identified the day after the surgery. Since the existing literature does not indicate the possibility of such complications in situations like ours, we insist that the potential for this technique to cause organ damage should be more widely known. Thus, we report a case of penetrating brain injury caused by a shunt tunneller, a very rare complication of VP shunting.