Pituitary & Skull Base Surgery Program


The Skull Base and Pituitary Tumor Program of the Pickup Family Neurosciences Institute aligns neurosurgeons, ENT surgeons, neurologists, neuro- opthalmologists, neuroradiologists and endocrinologists around the care of patients with pituitary tumors and other neoplasms of the intricate skull base region. The latter includes meningiomas, schwannomas, epidermoid tumors, and other invasive tumors that affect this portion of the anatomy.

The program focuses on combining the latest advanced and emerging technology with minimally invasive techniques in order to offer the best possible outcomes to patients with these rare and complex tumors. The majority of these surgeries are done through tiny incisions or using naturally occurring orifices such as the nostrils.

Since 2014, the Skull Base and Pituitary Program has seen dramatic growth under the program direction of Dr. Robert Louis. In the three years since the program’s inception, a total of 208 minimally invasive surgeries for tumor removal have been completed at Hoag.

This rapid growth in case volume speaks to the obvious demand for this subspecialty of neurosurgery in Orange County. While case volumes by themselves are a great measure of growth, what counts is the effect on patient outcomes. Numerous studies have demonstrated that surgeons and centers with more experience and which perform higher numbers of these complex cases have higher success rates and lower rates of complications. Indeed, a significant minority of the cases treated in our program are repeat surgeries for inadequate treatment from other facilities. As a result, Hoag’s Pickup Family Neurosciences Institute is establishing itself as the only Center of Excellence for Pituitary Surgery in Orange County. The three years of surgical outcome data, including remission and complication rates, are meeting or exceeding nationally established standards for pituitary surgery.

Technological Advances - Precision Neurosurgery

Since 2015, minimally invasive neurosurgery has been guided using the Surgical Navigation Advanced Platform (SNAP), by Surgical Theater. This giant leap forward for planning and performing brain surgery is a system developed and based on flight simulator technology for F-16 fighter jets. It allows for Virtual Reality 360 degree reconstruction, planning, rehearsal and navigation for complex neurosurgical procedures. By performing a Virtual Reality “fly-through” on each case, our surgeons are literally able to practice an operation in 3-D before ever picking up the scalpel. The tool optimizes minimally invasive approaches, smaller incisions, fewer complications, and better overall outcomes. In the two years since Surgical Theater was introduced at Hoag more than 700 surgical cases have been performed using this innovative technology.

Building upon the same platform, in 2017, EndoSNAP was introduced at Hoag. This provides the additional capabilities of Augmented Reality for endoscopic cases. The split screen view provided by the EndoSNAP gives the surgeon a “heads-up display” and allows for pinpoint accuracy and improved visualization of critical structures. Hoag remains the only center in California and ranks as the second highest volume center in the nation to use Augmented Reality in Neurosurgery.

The Skull Base and Pituitary Tumor Program’s technology enhanced clinical practice approach via implementation of a cutting-edge VR visualization platform was validated as shown by the following success measures:

  • 32% improvement in patient retention and outmigration rates resulting from consultations with patient-specific 360°VR models.
  • Higher rates of positive surgical outcomes and lower rates of complications compared to rates found in the literature (e.g., 71.4% visual improvement1, 74% gross total resection2, 8.5% readmission rate3, 2.3% post-op CSF leak3) for a wide range of complex procedures.
  • 42% and 50% YOY growth rates post-VR implementation with non-patient specific and patient-specific 360°VR models, respectively.


The Pituitary Program is led by Dr. Robert Louis, Board Certified Neurosurgeon and an expert in endoscopic and minimally invasive treatment of benign and malignant brain tumors, sellar, parasellar and skull base tumors. Dr. Louis’ unique background includes two fellowships in Complex Cranial Surgery and Minimally Invasive Skull Base and Pituitary Surgery. Dr. Timothy Kelley is the ENT surgeon and partners with Dr. Louis for many of these complex cases. His particular expertise lies in endoscopic sinus and skull base surgery.

Dr. Chris Duma is the director of the Brain Tumor Program but also serves a pivotal role in the Skull Base and Pituitary Program. Drs. Louis, Duma, and Kelley often work together, combining their skills and expertise to ensure the best possible outcome for patients.

The multidisciplinary team also includes endocrinologists, neuro-radiologists, ophthalmologists, neurologists, pathologists and neuro-oncologists

The nurse navigator for the program is Lori Berberet, R.N., who helps coordinate the complex and often confusing journey from diagnosis to cure.

Surgical Outcomes

  • 208 Surgical Cases - Tumor Resections designated as Skull Base/Pituitary/Minimally Invasive

    2014-2015 – 51

    2015-2016 – 76

    2016-2017 – 81

    Composed of pituitary adenoma, craniopharyngioma, Rathke’s Cleft Cysts, meningioma, schwannoma, metastases, epidermoid, dermoid, hemangioma, hemangioblastoma, SNUC, Olfactory Neuroblastoma

    Visual Improvement – 91%

    Gross total resection – 82%

    Biochemical Remission for functional tumors – 86%

    Readmission Rate – 3.6%

    Infection/Meningitis – 0.7%

    Post-op CSF leak – 2%

    Diabetes Insipidus – transient 38%, permanent 4%

Patient retention rate with surgical theater

  • Prior to ST- Jan-Sept 2015 – 64%
  • Using ST indexed “library” case videos as example – 82%

  • Using individualized ST custom built cases on office SNAP – 96%

Publications, Lectures, & Book Chapters

Click below to read more

Louis RG Jr, Whitesides JD, Kollias TF, Iwanaga J, Tubbs RS, Loukas M. Intercostal Nerve to Long Thoracic Nerve Transfer for the Treatment of Winged Scapula: A Cadaveric Feasibility Study. Cureus. 2017 Nov 30;9(11):e1898. doi: 10.7759/cureus.1898. PubMed PMID: 29399426; PubMed Central PMCID: PMC5790210.

Barkhoudarian G, Farahmand D, Louis RG, Oksuz E, Sale D, Villanueva P, Kelly DF. Microsurgical Endoscope-Assisted Gravity-Aided Transfalcine Approach for Contralateral Metastatic Deep Medial Cortical Tumors. Oper Neurosurg (Hagerstown). 2017 Dec 1;13(6):724-731. doi: 10.1093/ons/opx067. PubMed PMID: 29186601.

Loukas M, Du Plessis M, Louis RG Jr, Tubbs RS, Wartmann CT, Apaydin N. The subdiaphragmatic part of the phrenic nerve - morphometry and connections to autonomic ganglia. Clin Anat. 2016 Jan;29(1):120-8. doi: 10.1002/ca.22652. Epub 2015 Oct 30. PubMed PMID: 26457392.

Oldfield EH, Vance ML, Louis RG, Pledger CL, Jane JA Jr, Lopes MB. Crooke's Changes In Cushing's Syndrome Depends on Degree of Hypercortisolism and Individual Susceptibility. J Clin Endocrinol Metab. 2015 Aug;100(8):3165-71. doi: 10.1210/JC.2015-2493. Epub 2015 Jul 6. PubMed PMID: 26147609.

Louis RG, Eisenberg A, Barkhoudarian G, Griffiths C, Kelly DF. Evolution of minimally invasive approaches to the sella and parasellar region. Int Arch Otorhinolaryngol. 2014 Oct;18(Suppl 2):S136-48. doi: 10.1055/s-0034-1395265. Review. PubMed PMID: 25992138; PubMed Central PMCID: PMC4399582

Loukas M, Shane Tubbs R, Louis RG Jr, Apaydin N, Bartczak A, Vefali H, Alsaiegh N, Fudalej M. Erratum to: An endoscopic and anatomical approach to the septal papillary muscle of the conus. Surg Radiol Anat. 2015 Jul;37(5):569. doi: 10.1007/s00276-015-1422-y. PubMed PMID: 25601580.

Dallapiazza R, Bond AE, Grober Y, Louis RG, Payne SC, Oldfield EH, Jane JA Jr. Retrospective analysis of a concurrent series of microscopic versus endoscopic transsphenoidal surgeries for Knosp Grades 0-2 nonfunctioning pituitary macroadenomas at a single institution. J Neurosurg. 2014 Sep;121(3):511-7. doi: 0.3171/2014.6.JNS131321. Epub 2014 Jul 4. PubMed PMID: 24995783.

To learn more, visit the Pituitary & Skull Base Surgery section or call 949-764-6066.