**5. Failure rate and complications**

#### **5.1. Complications and their prevention**

Endoscopic ventriculostomy is considered less noninvasive and safe. The complications are rare and mostly related to the surgical procedure [85]. The average morbidity is 8.5% and mortality <1% [8, 11, 31, 85]. Permanent deficits are rare with an average value up to 2.38% [85], while the transient morbidity ranged up to 7.8% [8, 85].

**5.2. Failure rate and re-ETV**

is expressly recommended.

Joachim M.K. Oertel\* and Akos Csokonay

\*Address all correspondence to: joachim.oertel@uks.eu

Neurosurgical Department, University of Saarland, Homburg, Saar, Germany

**Author details**

Re-occlusion of the ventriculostoma is rare. Kulkarni et al. have reported that ETV has an initial higher failure rate in contrast to shunt placement, although it gets lower over time [5]. Most failures (58–97%) occur within the first 3 months [6, 7, 12, 62]. Within the first year, ETV failure reaches 16–20% [6, 62]. However, it might also develop after years; therefore, a longterm follow-up after the surgical procedure is required [12, 62, 89]. It remains controversial, whether re-ETV or shunt placement is the optimal choice of treatment for ETV failure. The decision depends on the age, etiology of hydrocephalus, imaging finding, and the duration between ventriculostomy and failure [63, 90]. In certain cases, repetition of ventriculostomy as the first choice is recommended, as a similar long-term success of 51–89% is expected [7, 16, 62, 63, 89, 91–94]. Some authors differentiate early failure from late failure, but the distinction between the two definitions is various (7 days—6 months) [4, 63, 89, 91, 93]. Multifactorial etiology including malabsorptive component, complications including hemorrhage and infection or technical failure as inadequate size of stoma with insufficient CSF flow through the stoma, and unperforated Liliequist membrane could be responsible for early failure [4, 63, 89, 93, 94]. The ideal size of stoma is not defined, and it seems to depend highly on the anatomy, while in case of a size between 4 and 7 mm, failures were also reported [89]. To avoid an intermitting CSF diversion through the shunt, ligature or removal of the shunt system is recommended, as mentioned above. Late failure could be caused by secondary closure as tumor progression, gliosis, and developing of membranes and adhesions in the subarachnoid space [4, 6, 11, 89, 91]. In children, the absorption of CSF at the Pacchionian granulations is immature [95], which may play a role in ETV failure. Further cause for failure might be the multifactorial etiology in certain cases [4]. The success of re-ETV is found higher in case of late-repeat-ETV than in early ones [63, 91, 96], although there are some controversial results [62]. As indicated above, the failure rate decreases during the follow-up [63]. Regarding the age, the results are controversial, but in most studies, higher failure rates are reported when less than 6–24 months of age [4, 63, 89]. Regarding the pathology, the failure rate amounts 10–20% in aqueduct stenosis, while in other indication cases, it amounts up to 50% [14]. If no obstructive cause for failure is seen on the MRI scan, a shunt placement is considered [63] taking a multifactorial etiology including malabsorptive mechanism as cause of failure. Re-ETV is also not recommended in case of tumor progression–related closure [89]. There are no exact criteria defined for repetition of ETV; an individual evaluation in all cases

Presentation of the Success Rate of ETV in Distinct Indication Cases of Hydrocephalus

http://dx.doi.org/10.5772/intechopen.72889

145

The most feared complication is the vessel injury. Minor hemorrhage can be caused by small vessel injuries, for example in the cortex, brain parenchyma, choroid plexus, or margin of ventriculostoma during inflation of the Fogarty catheter. Minor hemorrhage can be managed with irrigation to achieve a tamponade effect [8, 55, 85]. In case of insufficient irrigation, coagulation with bipolar diathermy should be performed [8]. Major hemorrhage caused by injury of basilar artery and basilar perforating vessels, thalamostriate vein, or anterior septal vein injury can lead to uncontrollable hemorrhage and life-tethering situation with fatal outcome. Minor hemorrhage occurs in up to 16.5%, whereas major ones occur only in 0.49% [85]. These may occur for example due to false placement of instruments [7]. Brain nerve injury may occur in the same way [7, 85]. In many diseases such as developmental anomalies and tumors, the anatomy is distorted making the surgical technique difficult [85]. By using a rigid endoscope and correct position of fenestration, these complications can be avoided. Thorough inspection of the anatomical relationships on the preoperative MRI scan is essential.

Further complications may be epidural or subdural hematoma [8, 86–88], fornix contusion [8, 31], traumatic damage of thalamus and hypothalamus with endocrine and electrolyte disturbances [31, 85], hemodynamic alterations [6, 85], cerebral herniation syndrome in case of obstructed outflow channel or excessive irrigation [8, 85], CSF leakage [8, 85], abandoned procedure, or ETV failure (see below) [6, 12, 62, 63, 89]. The incidence of abandoned procedure ranges from 0 to 26% [8]. The most frequent causes are hemorrhage, complex anatomical circumstances, or inability to fenestrate the ventricle floor [8]. Postoperative infection may lead to meningitis, ventriculitis, brain abscess, or sepsis. Further nonspecific complication as thrombophlebitis, pneumonia, or wound infection may occur.

Summarizing, to prevent the complications, individual anatomical variations should be evaluated in the preoperative imaging. The relationship between the third ventricle floor and basilar artery should be thoroughly considered. The adequate technique with rigid instrument should be used and one has to consider the correct energy intensity and sources. As mentioned above, it is recommended to use low energy (maximum 10 W) and to avoid laser and monopolar diathermy. The correct placement of fenestration is essential; ideally, it is placed halfway between the mammillary bodies and infundibular recess in the midline. However, individual variations should be considered. After the perforation, the interpeduncular and prepontine cistern should be inspected and adhesions or the Liliequist membrane should be perforated.

#### **5.2. Failure rate and re-ETV**

**5. Failure rate and complications**

144 Hydrocephalus: Water on the Brain

**5.1. Complications and their prevention**

MRI scan is essential.

should be perforated.

while the transient morbidity ranged up to 7.8% [8, 85].

thrombophlebitis, pneumonia, or wound infection may occur.

Endoscopic ventriculostomy is considered less noninvasive and safe. The complications are rare and mostly related to the surgical procedure [85]. The average morbidity is 8.5% and mortality <1% [8, 11, 31, 85]. Permanent deficits are rare with an average value up to 2.38% [85],

The most feared complication is the vessel injury. Minor hemorrhage can be caused by small vessel injuries, for example in the cortex, brain parenchyma, choroid plexus, or margin of ventriculostoma during inflation of the Fogarty catheter. Minor hemorrhage can be managed with irrigation to achieve a tamponade effect [8, 55, 85]. In case of insufficient irrigation, coagulation with bipolar diathermy should be performed [8]. Major hemorrhage caused by injury of basilar artery and basilar perforating vessels, thalamostriate vein, or anterior septal vein injury can lead to uncontrollable hemorrhage and life-tethering situation with fatal outcome. Minor hemorrhage occurs in up to 16.5%, whereas major ones occur only in 0.49% [85]. These may occur for example due to false placement of instruments [7]. Brain nerve injury may occur in the same way [7, 85]. In many diseases such as developmental anomalies and tumors, the anatomy is distorted making the surgical technique difficult [85]. By using a rigid endoscope and correct position of fenestration, these complications can be avoided. Thorough inspection of the anatomical relationships on the preoperative

Further complications may be epidural or subdural hematoma [8, 86–88], fornix contusion [8, 31], traumatic damage of thalamus and hypothalamus with endocrine and electrolyte disturbances [31, 85], hemodynamic alterations [6, 85], cerebral herniation syndrome in case of obstructed outflow channel or excessive irrigation [8, 85], CSF leakage [8, 85], abandoned procedure, or ETV failure (see below) [6, 12, 62, 63, 89]. The incidence of abandoned procedure ranges from 0 to 26% [8]. The most frequent causes are hemorrhage, complex anatomical circumstances, or inability to fenestrate the ventricle floor [8]. Postoperative infection may lead to meningitis, ventriculitis, brain abscess, or sepsis. Further nonspecific complication as

Summarizing, to prevent the complications, individual anatomical variations should be evaluated in the preoperative imaging. The relationship between the third ventricle floor and basilar artery should be thoroughly considered. The adequate technique with rigid instrument should be used and one has to consider the correct energy intensity and sources. As mentioned above, it is recommended to use low energy (maximum 10 W) and to avoid laser and monopolar diathermy. The correct placement of fenestration is essential; ideally, it is placed halfway between the mammillary bodies and infundibular recess in the midline. However, individual variations should be considered. After the perforation, the interpeduncular and prepontine cistern should be inspected and adhesions or the Liliequist membrane Re-occlusion of the ventriculostoma is rare. Kulkarni et al. have reported that ETV has an initial higher failure rate in contrast to shunt placement, although it gets lower over time [5]. Most failures (58–97%) occur within the first 3 months [6, 7, 12, 62]. Within the first year, ETV failure reaches 16–20% [6, 62]. However, it might also develop after years; therefore, a longterm follow-up after the surgical procedure is required [12, 62, 89]. It remains controversial, whether re-ETV or shunt placement is the optimal choice of treatment for ETV failure. The decision depends on the age, etiology of hydrocephalus, imaging finding, and the duration between ventriculostomy and failure [63, 90]. In certain cases, repetition of ventriculostomy as the first choice is recommended, as a similar long-term success of 51–89% is expected [7, 16, 62, 63, 89, 91–94]. Some authors differentiate early failure from late failure, but the distinction between the two definitions is various (7 days—6 months) [4, 63, 89, 91, 93]. Multifactorial etiology including malabsorptive component, complications including hemorrhage and infection or technical failure as inadequate size of stoma with insufficient CSF flow through the stoma, and unperforated Liliequist membrane could be responsible for early failure [4, 63, 89, 93, 94]. The ideal size of stoma is not defined, and it seems to depend highly on the anatomy, while in case of a size between 4 and 7 mm, failures were also reported [89]. To avoid an intermitting CSF diversion through the shunt, ligature or removal of the shunt system is recommended, as mentioned above. Late failure could be caused by secondary closure as tumor progression, gliosis, and developing of membranes and adhesions in the subarachnoid space [4, 6, 11, 89, 91]. In children, the absorption of CSF at the Pacchionian granulations is immature [95], which may play a role in ETV failure. Further cause for failure might be the multifactorial etiology in certain cases [4]. The success of re-ETV is found higher in case of late-repeat-ETV than in early ones [63, 91, 96], although there are some controversial results [62]. As indicated above, the failure rate decreases during the follow-up [63]. Regarding the age, the results are controversial, but in most studies, higher failure rates are reported when less than 6–24 months of age [4, 63, 89]. Regarding the pathology, the failure rate amounts 10–20% in aqueduct stenosis, while in other indication cases, it amounts up to 50% [14]. If no obstructive cause for failure is seen on the MRI scan, a shunt placement is considered [63] taking a multifactorial etiology including malabsorptive mechanism as cause of failure. Re-ETV is also not recommended in case of tumor progression–related closure [89]. There are no exact criteria defined for repetition of ETV; an individual evaluation in all cases is expressly recommended.

#### **Author details**

Joachim M.K. Oertel\* and Akos Csokonay \*Address all correspondence to: joachim.oertel@uks.eu Neurosurgical Department, University of Saarland, Homburg, Saar, Germany
