AANS Neurosurgeon | Volume 28, Number 4, 2019

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Gray Matters: Bringing Polemic Issues with Inchoate Guidelines into Sharper Focus

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Approaches for Tuberculum Sella Meningioma

Case Description
This 56 year-old right-handed woman presented with a nine-month history of gradually progressive bilateral vision loss (left eye greater than the right) and daily frontal headaches. She has no significant medical or surgical co-morbidities. Her neurological examination did not reveal any deficits other than the visual field loss indicated below. A contrast-enhanced MRI study of the brain revealed a homogeneously enhancing dural-based mass arising from the region of the tuberculum sella with suprasellar extension and compression of the optic chiasm.

Gray Matters PreOP with hmphery

Figure 1. Pre-operative sagittal and coronal T1 weighted post-gadolinium enhanced MRI and Humphrey visual fields.

How would you approach this tumor?

View Results

Discussion
Planum sphenoidale and tuberculum sella meningiomas arise from the floor of the anterior cranial fossa near the midline and present with visual disturbances due to compromise of the optic nerves and chiasm necessitating surgical removal in most cases. The traditional craniotomy and open surgical removal with decompression of the optic apparatus has been effectively used for many years.

A minimally invasive cranial approach via a supraorbital incision and bone opening is also reportedly used quite effectively to remove these tumors. Another option is the endoscopic endonasal approach (EEA) that has been increasingly used for this purpose over the past decade, and in experienced hands, has proven to be a safe and effective option as well. To date, the literature is limited primarily to small single institution, retrospective studies and meta-analyses comparing outcomes between the EEA and transcranial approaches. Here are a few seminal reviews.

In 2012, Komotar et al., published a meta-analysis of 60 studies involving 1,426 patients with tuberculum sellae, planum sphenoidale or olfactory groove meningiomas, that were resected either via an EEA or transcranial approach. Gross total resection (GTR) for olfactory groove meningiomas was reported in 92.8 percent of patients in the open cohort, compared to 63.2 percent of the endoscopic cohort. For tuberculum sellae and planum meningomas, GTR was reported in 84.1 percent of patients in the open cohort, compared to 74.7 percent of the endoscopic cohort. With regard to postoperative outcomes, the rate of cerebrospinal fluid (CSF) leak was significantly higher in the endoscopic cohort at 21.3 percent while only 4.3 percent in the open cohort. Rate of CSF leak of olfactory groove meningiomas was reported as 6 percent in the open cohort compared to 31.6 percent in the endoscopic cohort. A vascularized nasoseptal flap was not consistently used in the endoscopic cohort, which may account for the higher rate of CSF leak. More recent reports of endoscopic skull base tumor resection, with the use of a vascularized nasoseptal flap, consistently report CSF leak rates that are < 10 percent. Postoperative anosmia, hemorrhage and mortality were similar between cohorts. Importantly, postoperative visual function recovery was similar in both groups.

In 2013, Clark et al., reported the results of their meta-analysis of 15 studies published in the last decade comparing outcomes of patients with tuberculum sella meningiomas who underwent EEA or transcranial approaches. There was no significant difference in age, sex, tumor diameter, volume or preoperative visual acuity or visual field deficit between the two groups. The authors found no significant difference in the rate of GTR between the two groups; 60-92 percent for EEA and 74-92 percent for transcranial approaches. There was also no significant difference in total perioperative complications between the two groups; the complication rate was approximately 20 percent for patients regardless of surgical approach.

However, a significant difference was reported in the rate of CSF leak: 0-62 percent for the EEA vs. 0-8 percent for transcranial. However, this meta-analysis did not examine any studies which utilized the vascularized nasoseptal flap which has been demonstrated to significantly reduce CSF leak rates to the 3-5 percent range similar to what is observed with the transcranial approach. However, what was important was the significantly better postoperative-vision improvement noted in the EEA group (87 percent) compared to the transcranial-approach group (59 percent). No significant difference in the rate of postoperative visual worsening was noted between each approach, and it was estimated at 6-12 percent.

In 2014, Koutourousiou et al., published results of the EEA in 75 patients with meningiomas originating from the tuberculum sellae and/or planum sphenoidale. Approximately 85 percent of patients experienced either improvement in visual function or complete return to baseline.  Simpson grade 1 resection was achieved in 81.4 percent of patients in whom GTR was the goal. Factors that correlated with reduced rates of GTR included tumor size, vascular encasement and multilobular tumor shape. Tumors greater than three centimeters in diameter had a GTR rate of 20 percent, compared to 84.6 percent for tumors less than three centimeters in diameter. Vascular encasement of tumor reduced the GTR rate from 91.1 percent to 31.6 percent.

Lastly, multilobular tumors had a GTR rate of 43.5 percent, compared to 90.4 percent for uniform round tumors. The postoperative CSF leak rate during the entire study period was 25.3 percent; however, during the last two years when use of the vascularized nasoseptal flap became routine, the CSF leak rate was reduced to 11.7 percent. Postoperative visual deterioration was reported in 3.6 percent.

The information in these studies can be distilled into practical surgical experience and the relative merits of each approach become evident. The cranial approaches (subfrontal, pterional or supraorbital) allow direct visualization of the tumor, optic nerves, supraclinoid carotid arteries and the ACA complex.

Modern techniques and anesthesia have minimized the morbidity associated with a craniotomy, and most neurosurgeons are comfortable with the anatomy. There is also direct control of the tumor and associated vasculature, and the ability to manage bleeding may be superior given the magnification and clarity provided by the operating microscope. On the other hand, the EEA allows direct access to the tumor base and vasculature that can be coagulated to minimize bleeding, and there may be less manipulation of the optic nerves and intracranial vasculature. It also avoids brain retraction and manipulation of important and sensitive anatomical structures.

But, there are limitations to the EEA. It is difficult to access and resect larger tumors with lateral extension, especially lobulated tumors and those with vascular encasement or cavernous sinus invasion. In addition, large tumors may lack an arachnoid plane, increasing the risk for vascular injury, postoperative visual decline, and the ability to control vascular structures and bleeding encountered during surgery is very limited. The available tools (pistol grip or other bipolar cautery) are ungainly and cumbersome to use, and the ergonomics of dealing with a bleeding vessel at a fair distance through the nasal route is poor. Another drawback is the risk of postoperative CSF leakage and concomitant risk of meningitis.

Our approach is to carefully consider the morphology and location of the tumor and its relationship to major vascular structures, such as the internal carotid and anterior cerebral artery, and its branches (the pericallosal arteries) and the optic nerve and chiasm. Encasement of an extension lateral to the internal carotid artery, or invasion of the cavernous sinus, make it challenging from an EEA perspective and almost impossible to achieve a complete resection without significant morbidity.

Our practice is to consider the EEA for tuberculum sella and planum sphenoidale meningiomas that are medial to the ICA and in patients who have a well pneumatized sphenoid sinus. Size is a relative factor, and each case is carefully individualized, based on the extent of suprasellar extension and involvement of structures, such as the third ventricle. Intracapsular debulking is a reasonable maneuver, but in some instances with a small tumor, an extracapsular arachnoidal plane dissection can also allow a clean removal of the tumor with preservation of the adjacent critical neurovascular structures. Visual outcomes with the EEA approach appear to be equivalent or superior to the transcranial approach for carefully selected planum sphenoidale and tuberculum sella meningiomas. Decompression of the optic nerve and chiasm from below is easily accomplished and can be done without significant manipulation of the blood supply to the optic apparatus. The risk of a CSF leak with the EEA is significantly minimized with the use of a vascularized nasoseptal flap.

The transcranial approaches may be better suited for a planum sphenoidale or tuberculum sella meningioma that is large, lobulated and with significant lateral extension or with vascular encasement; they accord better control of the vasculature and betters tools to deal with vascular complications. Utilizing a pterional or bifrontal craniotomy does not add significant morbidity over the supraorbital approach, which may be an option for smaller tumors. The transcranial approaches may be ideally suited for olfactory groove meningiomas that are in a different category from those arising from the planum sphenoidale and tuberculum sella. They tend to be eccentric towards one side and extend above the chiasm lending to better access via one of the cranial approaches. Ultimately, the optimal approach is predicated on the judgement and experience of the surgeon, and the individual patient characteristics and should be carefully determined on an individual case-by-case basis. Having both these surgical options in a surgeon’s armamentarium provides the ideal situation.

References

1. Komotar, R. J., Starke, R. M., Raper, D. M., Anand, V. K. & Schwartz, T. H. 2012. Endoscopic endonasal versus open transcranial resection of anterior midline skull base meningiomas. World Neurosurg, 77, 713-24.

2. Clark, A. J., Jahangiri, A., Garcia, R. M., George, J. R., Sughrue, M. E., McDermott, M. W., El-Sayed, I. H. & Aghi, M. K. 2013. Endoscopic surgery for tuberculum sellae meningiomas: a systematic review and meta-analysis. Neurosurg Rev, 36, 349-59.

3. Koutourousiou, M., Fernandez-Miranda, J. C., Stefko, S. T., Wang, E. W., Snyderman, C. H. & Gardner, P. A. 2014. Endoscopic endonasal surgery for suprasellar meningiomas: experience with 75 patients. J Neurosurg, 120, 1326-39.

 

The Experts Weigh In

 

The Case for Endonasal Endoscopic Approach for Tuberculum and Planum Meningiomas

Theodore H. Schwartz MD, FAANS; New York
Click here to read this expert's comments.
Theodore H. Schwartz MD, FAANS; New York
Insights from the experts:

Schwartz

Drs. Driver, Johans, Welch and Prabhu present a case of a small tuberculum sella meningioma resected using an endonasal endoscopic approach (EEA). Their surgical results are outstanding, as demonstrated in the accompanying surgical video, and their logic for choosing this approach is supported by a discussion of the some of the relevant literature. At Weill Cornell Medical College, we have been using the EEA for planum and tuberculum meningiomas since 2004 and have removed 41 tumors to date. EEA is considered first as the optimal approach for reasons to be discussed later; however, during this same time period, we have opted to use a craniotomy in a handful of cases. The indications and contraindications we employ, as well as our surgical technique, differ slightly from those presented by the group from Loyola which will form the basis of our discussion.

The literature review presented by Driver et al., point out that visual outcome for the endonasal approach appears to be superior to the transcranial approach with similar rates of extent of resection and higher rates of CSF leak. However, these results were obtained using data from the beginning of the learning curve at most high volume EEA centers, whereas results for transcranial approach are at the plateau of the learning curve for most academic centers.

We recently published a series of 12 consecutive cases operated on between 2008 and 2012, after an initial learning curve of eight cases. In this series, we achieved a GTR rate of 91.7 percent, a visual improvement rate of 88.9 percent and a CSF leak rate of zero percent (1).  These results, from a mature experienced group, albeit in a limited number of patients, indicates that the EEA can achieve results superior to transcranial surgery for well-selected cases. In our hands, the low CSF leak rate is not just attributable to the use of a nasoseptal flap but also the “gasket-seal” closure which involves buttressing an overlay of fascia lata with a Medpore (Porex) graft (2, 3, 4, 5). Moreover, the EEA permits improved visualization and removal of tumor from the medial optic canals, as well resection of the diaphragma sella, assuming an adequately large bone opening is created (6, 7, 8, 9). Finally, the rates of seizure and wound infection are higher for craniotomy than for EEA (10).

The contraindications and indications we use, as well as our surgical technique, differ slightly from those presented by Driver et al. Although we agree that the tumor must be medial to the carotids, we use the ICA bifurcation as the lateral limit. The anterior clinoid is also a good lateral limit with respect to the base of the tumor. Vascular encasement and the presence of a “cortical cuff” between the tumor and the neighboring vessels are only a relative contraindication. In a recent paper, we have shown that the presence of a cortical cuff and brain edema does not impact outcome as much as surgeon experience, with respect to both technical expertise and case selection (11).

Encasement must be confirmed on all three planes as 360-degree encasement. In some cases, “pseudo-encasement” in one plane is really a 180- or 270-degree encasement in a different plane, and in this circumstance, there is often an arachnoid plane between the tumor and the vessel. If the tumor cannot be dissected off a small perforator, then the tumor is left behind as it would be following a craniotomy. However, encasement of the optic nerves, or tumor lateral to the optic nerves, has been a contraindication we have used to favor a transcranial approach. Invasion of the cavernous sinus limits EEA, as it limits a transcranial approach, but in some circumstances, the EEA can be useful to interpose a fat graft between the normal pituitary gland and optic apparatus and the residual cavernous sinus tumor in preparation for stereotactic radiosurgery, the so-called “hypophysopexy” (12).

Finally, the technique demonstrated in the accompanying video, which clearly obtained outstanding results, differs from our own in a few respects. First, the authors removed the planum spenoidale anteriorly beyond the limits of the dural attachment and thus, created a larger opening than was required, which renders closure more difficult. In addition, we do not remove meningiomas en bloc, but rather perform an internal decompression followed by careful sharp extracapsular dissection under direct vision. If the tumor is soft, then suction is generally all that is required. If the tumor is firm, we prefer to use the Elliquence (Elliquence), since the tip can be bent to maximize visualization.

In some situations, the superior hypophyseal arteries or the anterior communicating complex, and its perforators, can be stuck to the back of the tumor, and blind sweeping of instruments or pulling of the tumor can result in vascular injury. In addition, we always cauterize the superior intercavernous sinus and resect the diaphragma sella, which often contains tumor cells.  

In conclusion, our experience has shown that for the majority of planum and tuberculum sella meningiomas, the EEA is preferred over the craniotomy approach. However, proper technical experience, appropriate equipment and mature case selection criteria are necessary to achieve optimal results.

Theodore H. Schwartz MD, FAANS, is professor of neurosurgery, otolaryngology and neuroscience and is the David and Ursel Barnes Professor of minimally invasive neurosurgery at Weill Cornell Medical College, New York Presbyterian Hospital in New York.

References
1. Ottenhausen M, Banu M, Placantonakis DG, Tsiouris AJ, Khan OH, Anand VK, Sschwartz TH. 2014. Endoscopic endonasal resection of suprasellar meningiomas: the importance of case selection and experience in determining extent of resection, visual improvement and complications World Neurosurgery 83;3/4:442-449.

2. Leng L, Brown S, Anand, VK, Schwartz TH. 2008. “Gasket-seal” watertight closure in endoscopic cranial base surgery. Neurosurgery 62;ONS Suppl 2:ONSE342-343.

3. Garcia-Navarro V, Anand VK, Schwartz TH. 2013. The “Gasket-Seal” closure for extended endonasal endoscopic skull base surgery. Long-term efficacy in a large case series. World Neurosurgery 80;5:563-8.

4. Mascarenhas L, Moshel YA, Bayad F, Szentermai O, Salek AA, Leng LZ, Hofstetter CP, Placantonakis DG, Tsouris AJ, Anand VK, Schwartz TH. 2014. The transplanum transtuberculum approaches for supr asellar and sellar-suprasellar lesions. Avoidance of CSF leak and lessons learned. World Neurosurgery 82 (1/2): 186-95.

5. Patel KS, Komotar R, Szentirmai O, Moussazadeh N, Raper DM, Starke RM, Anand VK, Schwartz TH. 2013. Case-specific protocol to reduce CSF leakage after endonasal endoscopic surgery. J. Neurosurgery 119;3:661-8.

6. Woodworth GF, McCoul ED, Greenfield JG, Anand VK, Schwartz TH. 2011. Endoscopic management of anterior cranial fossa meningiomas Op. Tech.Otol-Head Neck Surg. 22;4:254-263.

7. Komotar RJ, Starke RM, Raper DMS, Anand VK, Schwartz TH. 2012. Endoscopic endonasal versus open repair of anterior skull base meningiomas: a systematic meta-analysis of outcomes. World Neurosurgery 77;5/6:713-724.

8. Kulwin C, Schwartz TH, Cohen-Gadol AA. 2013. Endoscopic extended transsphenoidal resection of tuberculum sella meningiomas: nuances of neurosurgical technique . Neurosurgery Focus 35;6:E6.

9. Attia M, Kandasamy J, Jakimovsky D, Bedrosian J, Alimi M, Anand VK, Schwartz TH. 2012. The importance and timing of optic canal exploration and decompression during endonasal resection of tuberculum sella and planum sphenoidale meningiomas. Operative Neurosurgery 71(1 Suppl Operative):58-67.

10. Komotar, RJ, Starke, RM, Raper, DM, Anand, VK & Schwartz, T. H. 2012. Endoscopic endonasal versus open transcranial resection of anterior midline skull base meningiomas. World Neurosurg, 77, 713-24.

11. Khan OH, Anand VK, Schwartz TH. 2014. Endoscopic endonasal resection of skull base meningiomas: the significance of a “cortical cuff” and brain edema compared with surgical experience and case selection in predicting morbidity and extent of resection. Neurosurgical Focus 37;4:E7.

12. Couldwell WT, Rosenow JM, Rovit RL, Benzil DL. 2002. Hypophysopexy technique for radiosurgical treatment of cavernous sinus pituitary adenoma. Pituitary 5:169–173.

The Case for Supraorbital “Eyebrow” Craniotomy for Tuberculum Sella Meningiomas

Garni Barkhoudarian MD; New York; Daniel F. Kelly MD, FAANS; Santa Monica, Calif
Click here to read this expert's comments.
Garni Barkhoudarian MD; New York; Daniel F. Kelly MD, FAANS; Santa Monica, Calif
Insights from the experts:
Kelly Barkhoudarian

Daniel F. Kelly, MD, FAANS; Garni Barkhoudarian, MD.

Dr. Driver and his colleagues demonstrate the successful use of the extended endonasal transplanar approach for resection of a small tuberculum sella meningioma causing vision loss. The accompanying video demonstrates excellent, en-bloc resection of this tumor which was reflected by the post-operative imaging. The dural defect was repaired with a multi-layered closure including a pedicled nasoseptal vascular flap. They discussed three recent studies reviewing the extended endonasal approach for anterior fossa meningiomas, including two meta-analyses. Though there is a significantly increased rate of cerebrospinal fluid (CSF) rhinorrhea with the endonasal techniques, the adoption of the pedicled nasoseptal vascular flap (2) has decreased this rate in more recent publications (5-16 percent) (3, 4). The authors advocate the extended endonasal approach for such tumors, taking into account specific tumor characteristics and surgeon experience.

At our institution, the Brain Tumor Center and Pituitary Disorders Program at Saint John’s Health Center, the extended endonasal approaches are a component of our keyhole approach armamentarium, which includes the supraorbital “eyebrow” craniotomy to complement the endonasal transplanar approach (6). Both approaches have specific advantages and disadvantages to take into consideration when choosing the best option for a frontal fossa and parasellar tumors.

As the authors delineate, certain characteristics of this particular meningioma afford a favorable outcome with the endonasal approach. These included the presence of an arachnoid plane, the lack of vascular encasement, the location medial to the supraclinoid carotid arteries and the extent into the sella. Though a clear CSF cleft was not visible on the T2 weighted MRI images provided, the lack of visible vasogenic cerebral edema suggests no significant pial vascular parasitization. The midline nature of this tumor decreases the challenges of endonasal visualization of lesions lateral to the carotid artery. Certainly, angled endoscopes and instruments can reach a degree of lateral extension, but with some compromise of vascular control and potential for residual tumor.

Conversely, many of the aspects of the presented tumor could easily support a supraorbital “eyebrow” craniotomy. The frontal sinuses are quite small, diminishing the chance of their exposure and potential of CSF rhinorrhea with the eyebrow craniotomy. Nevertheless, we typically prepare for an abdominal fat graft to help seal the sinus in such a scenario. The long axis of the tumor is relatively parallel with a supraorbital approach, requiring no significant frontal lobe retraction or displacement. For tumors with more significant superior extension, as is more commonly seen with suprasellar craniopharyngiomas, the endonasal approach would benefit from improved “line-of-sight”. Though there is no obvious vascular encasement, MRI imaging cannot reliably predict a clean arachnoid plane separating the tumor from the anterior cerebral arteries, optic apparatus or the superior hypophyseal arteries (7). 

Hence, there is some degree of improved vascular control with the supraorbital approach. As is frequently seen with tuberculum sella meningiomas, the optic chiasm is displaced superiorly and posteriorly. This allows for a en-bloc resection as was depicted in the video, but also confers an unobstructed avenue to the entire tumor with the supraorbital approach. While the sella is somewhat deepened by the meningioma and there is some extension of the tumor below the level of the planum, this degree of sellar extension is typically readily accessible with the supraorbital approach, especially with the use of a 30-degree endoscope  and angled ring curettes. In our practice, whether craniotomy or endonasal, we typically debulk the tumor prior to its dissection off surrounding structures, hence en-bloc resection is not a pivotal factor.

In our experience, tumors that confer favorability for the endonasal approach include retro-chiasmal lesions (commonly retrochiasmal craniopharyngiomas), tumors with significant suprasellar and even third ventricular extension and lesions with very deep (inferior) sellar/sphenoidal extension (1). 

Meningiomas that are better treated with the supraorbital approach include larger lesions (> 30-35 millimeters), lateral extension beyond the supraclinoidal carotid arteries, vascular encasement and significant cortical invasion. For lesions like the tumor presented, certainly either approach can confer similar tumor resection potential, as well as low complication rates. 

A higher rate of CSF rhinorrhea has been reported with the endonasal approaches. However, with the nasoseptal flap, most contemporary, high-volume series report less than five percent leak rates, more recently approaching zero percent — particularly with the gasket-seal augmentation (5). Nevertheless, one should take into account other risk factors for post-operative CSF leak, such as obesity, sleep apnea — especially requiring CPAP therapy — as well as other causes of elevated intracranial pressure.  A thorough sinonasal evaluation should also be performed to assess for viable nasoseptal flap options.

When either approach is equally viable, a thorough discussion should be held with the patient including anticipatory guidance for post-operative recovery. Most patients undergoing extended endonasal approaches have six to 12 weeks of sinonasal dysfunction associated with dysosmia, dysgeusia, nasal crusting and frequent endoscopic cleanings by the sinonasal surgeon. 

On the other hand, patients undergoing an eyebrow approach have the potential of a visible facial incision (especially in those with thin or absent eyebrows), and typically experience two to three months of unilateral frontalis paresis and supraorbital hypesthesia. Minor complications, such as sinusitis or pressure urticaria (due to a tight head-wrap) can also affect overall outcomes and patient satisfaction. These factors, in conjunction with the surgeons’ experience and preference, should guide the decision as to the optimal approach for each patient.

Garni Barkhoudarian, MD, is assistant professor of neuroscience/neurosurgery at the Brain Tumor Center & Pituitary Disorders Program at the John Wayne Cancer Institute at Saint John’s Health Center in Santa Monica, Calif. Daniel F. Kelly, MD, FAANS, is the director of the Brain Tumor Center at the John Wayne Cancer Institute at Saint John’s Health Center.

References
1. Fatemi N, Dusick JR, de Paiva Neto MA, Malkasian D, Kelly DF: Endonasal versus supraorbital keyhole removal of craniopharyngiomas and tuberculum sellae meningiomas. Neurosurgery 64:269-284; discussion 284-266, 2009

2. Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, et al: A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope 116(10):1882-1886, 2006

3. Koutourousiou M, Fernandez-Miranda J, Stefko S, Wang E, Snyderman C, Gardner P: Endoscopic endonasal surgery for suprasellar meningiomas: experience with 75 patients. Journal of neurosurgery 120:1326, 2014

4. Leng LZ, Brown S, Anand VK, Schwartz TH: ” Gasket-seal” watertight closure in minimal-access endoscopic cranial base surgery. Neurosurgery 62:ONSE342, 2008

5. Mascarenhas L, Moshel YA, Bayad F, Szentirmai O, Salek AA, Leng LZ, et al: The Transplanum Transtuberculum Approaches for Suprasellar and Sellar-Suprasellar Lesions: Avoidance of Cerebrospinal Fluid Leak and Lessons Learned. World neurosurgery 82:186, 2014

6. Reisch R, Perneczky A: Ten-year experience with the supraorbital subfrontal approach through an eyebrow skin incision. Neurosurgery 57:242, 2005

7. Zada G, Du R, Laws ER Jr: Defining the” edge of the envelope”: patient selection in treating complex sellar-based neoplasms via transsphenoidal versus open craniotomy. Journal of neurosurgery 114:286, 2011

 

Gray Matters PosOP

Figure 2. Post-operative sagittal and coronal T1 post-gadolinium enhanced MRI showing tumor resection.

Patient history and intra-operative video.

 

Results from previous Gray Matters Survey

Topic: Normal Pressure Hydrocephalus

What option would you select:
  • Continued observation
    21%, 21 Votes
  • Lumboperitoneal shunt
    6%, 6 Votes
  • Ventriculoperitoneal shunt
    62%, 60 Votes
  • Endoscopic third ventriculostomy
    9%, 9 Votes
  • Total Votes: 96

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