Pituitary & Skull Base Surgery Program


The Skull Base and Pituitary Tumor Program aligns neurosurgeons, ENT surgeons, neurologists, neuro- opthalmologists, neuroradiologists, endocrinologists around the care of patients with pituitary tumors, and other neoplasms of the intricate skull base region. The latter includes meningiomas, chordomas, 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 its introduction in 2014, the Skull Base and Pituitary Program has seen dramatic growth under the program direction of Dr. Robert Louis. In the year prior to his arrival, only six pituitary and skull base cases were performed. This has risen dramatically to 51 cases in the first year and 112 cases in the second year (matching many academic medical centers).

This rapid growth in case volume speaks to the obvious need 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 Neurosciences Institute is establishing itself as the Center of Excellence for Skull Base and Pituitary Surgery in Orange County.

New Advances in 2016

In conjunction with Dr. Christopher Duma, Dr. Louis helped to develop and introduce 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 3D 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. Hoag Neurosciences Institute is one of only 11 sites in the country, and the only non-academic one to be using this technology.


The Pituitary Program is led by Dr. Rob Louis, an expert in endoscopic and minimally invasive treatment of benign and malignant brain tumors, sellar and parasellar tumors 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 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.


  • 112 total cases performed
  • 76 tumor resections
  • 58 gross total resection
  • 77 showed symptomatic improvement
  • 1.78% mortality rate at 90 days
  • 4.4% complication rate

Publications, Lectures, & Book Chapters

  1. Villanueva P, Louis RG, Cutler AR, Wei H, Sale D, Duong HT, Barkhoudarian G, Kelly DF. Endoscopic and Gravity-Assisted Resection of Medial Temporo-occipital Lesions Through a Supracerebellar Transtentorial Approach: Technical Notes With Case Illustrations. Neurosurgery. 2015 Aug 14.
  2. 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.
  3. 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.
  4. 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.


  1. Louis RG, Schmitt PJ, Payne S, Jane Jr JA. Transsphenoidal Surgery for Pituitary Tumors -How I Do It. In Becker and Castelnuevo (Eds) Atlas of surgery on the nose, paranasal sinuses and skull base. 2014.
  2. Schmitt PJ, Louis RG, Payne S, Jane Jr JA. Pediatric Craniopharyngiomas. In Becker and Castelnuevo (Eds) Atlas of surgery on the nose, paranasal sinuses and skull base. 2014.
  3. Payne S, Louis RG, Jane Jr JA. Sellar and Parasellar Approaches. In Singh, Payne and Wooworth (Eds) Surgical Techniques in Otolaryngology – Head and Neck Surgery. JP Medical Publishing 2014
  4. Louis RG, Barkhoudarian G, Kelly DF. Surgical Approaches - Complications of Surgical Management. In Kenning and Evans (Eds) Craniopharyngiomas: A Comprehensive Guide to Diagnosis, Treatment, and Outcome. 2014.


Featured in Orange County Register with the SNAP Technology

Physician Spotlight feature by the Pituitary Network Association, which is the largest pituitary patient support group in the country.