Principles of Pituitary Surgery

Key Points 1. Understand the principles of pituitary surgery including the key-elements of surgical planning and decision-making 2. Identify the technical nuances distinguishing the endoscopic from the microscopic transsphenoidal approach 3. Understand the strategies utilized during the nasal, sphenoidal, and sellar stages of surgery that maximize tumor resection while minimizing complications and preserving sino- nasal anatomy/functio

Chevalier Jackson, M.D. (1865-1958): Il ne se repose jamais.

In the final year of the American Civil War, 1865, Chevalier Jackson was born on the 4th of November just outside Pittsburgh, Pennsylvania. The eldest of three sons of a poor, livestock-raising family, Jackson was raised in a period of social and political unrest. He was perhaps an even more unrestful boy. The description of his childhood days from his father’s father—Il ne se repose jamais, ‘‘He never rests’’—would ultimately reflect the man, doctor, and evangelist Jackson would later become.1 Indeed, he never did rest, Jackson would tirelessly pave the way for modern bronchoscopy and endoscopy as a whole; bringing international renown not only to himself, but also to his specialty

Fractionated Stereotactic Radiosurgery Alone for the Treatment of a Papillary Craniopharygioma

The use of radiation treatment (RT) is usually reserved for residual or recurrent craniopharyngiomas, and the role of RT alone and not as an adjunctive therapy to surgery has not been clearly defined. The authors describe a case of a 50-year-old man presenting with a large suprasellar craniopharyngioma with extension into the third ventricle, producing acute hydrocephalus. A ventriculoperitoneal shunt was performed concurrently with an endoscopic biopsy. Treatment with fractionated stereotactic radiosurgery (FSR) resulted in near resolution of the lesion with no evidence of recurrence over six years. A review of RT for the treatment of craniopharyngiomas without surgical resection is performed

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a chronic, progressive facial pain disorder characterized by severe paroxysmal episodes in the distribution of the trigeminal nerve. The most common cause of (TN) is compression of the trigeminal nerve by a vascular structure within the posterior fossa at the dorsal root entry zone (DREZ). Initially described by Dr. Peter Janetta, microvascular decompression has been clearly demonstrated to be a safe and effective treatment for TN with excellent immediate and long-term pain relief.1 Although neuroimaging has advanced significantly allowing for improved pre-operative visualization of the trigeminal nerve and determination of vascular conflict, most neurosurgeons continue to practice the MVD procedure in a very similar manner to Dr. Janetta’s 1967 description.2 While the retrosigmoid craniotomy and operative microscope allows for an excellent view of the posterior aspect of the trigeminal nerve within the cerebellopontine angle, visualization of the anterior aspect of the nerve is limited. Additionally, adequate visualization of the DREZ may be difficult and require additional retraction of the cerebellum, potentially resulting in complications such as hearing loss and cerebellar injury. As neurosurgical experience with the endoscope has grown, a variety of authors have described performing microvascular decompression with endoscopic assistance which involves using the endoscope to inspect the trigeminal nerve for sites of compression but performing the decompression under the microscope. While the main advantage of the endoscopic approach compared to the microscopic approach is improved visualization of the trigeminal nerve from the DREZ to Meckel’s cave including its inferior, anterior and superior surfaces, evolution of the procedure to a fully endoscopic approach has the additional benefits of being less invasive with minimal soft tissue dissection and cerebellar retraction allowing for reduced patient discomfort and accelerated recovery. In this technical review, we describe our approach to performing a fully endoscopic microvascular decompression including the surgical nuances that allow the procedure to be performed safely and efficiently. Pages 2-

Parallel simulation of character recognition problems using NEUCOMP2

NEUCOMP2 is a parallel Neural Network Compiler for a shared-memory parallel machine. It compiles a program written as a list of mathematical specifications of Neural Network (NN) models and then translates it into a chosen target program which contains parallel codes. Performance results for character recognition problems on popular NN models are presented. The models are the backpropagation, Kohonen, Counterpropagation and ART1 network models. NEUCOMP2 was developed and run on the SEQUENT Balance 8000 computer system at PARC

Is Reconstruction of the Sella Necessary to Prevent Optic Chiasm Prolapse and Cerebrospinal Fluid Leakage Following Endoscopic Resection of Pituitary Macroadenomas?

Visual compromise is a common presentation of pituitary macroadenomas and is related to direct optic nerve and chiasm compression. Although the extent of visual recovery following treatment depends on the duration and severity of the visual compromise, the majority of patients experience gradual improvement in their vision. Delayed visual deterioration following treatment is typically related to either tumor recurrence or radiation-induced optic neuropathy, although visual worsening due to prolapse of the optic apparatus into a secondary empty sella has rarely been reported. In 1968, Guiot reported the first a case of reversible visual deterioration associated with optic chiasm prolapse following resection of a large pituitary macroadenoma (Guiot). Based on their observations, Guiot and collaborators recommended that a “prop” be placed in the sella at the time of transsphenoidal pituitary adenoma resection to prevent progressive herniation of the optic structures. Similarly, Hardy coined the term “preventive chiasmopexy” to describe filling of the sella cavity with autologous tissue such as muscle or fat following resection of large tumors to prevent this herniation phenomenon. While optic chiasm prolapse with associated visual deterioration appears to represent a rare occurrence, its true incidence and pathophysiological basis remain uncertain. Reconstruction of the sella with autologous tissues is also widely employed as a means to prevent postoperative cerebrospinal fluid leakage with these tissues typically harvested from a secondary operative site such as the abdomen. Although not frequently reported in the pituitary literature, complications of abdominal fat graft harvest include hematoma and seroma formation as well as infection with an incidence ranging from 1-7%. At our institution, we do not routinely perform dural reconstruction following transsphenoidal resection of pituitary macroadenomas using adipose tissue to prevent cerebrospinal fluid leakage or optic chiasm prolapse. In this study, we sought to determine the incidence of optic chiasm prolapse into the sellar defect by determining the radiographic position of the optic chiasm following surgery and incidence of delayed visual deterioration. Pages: 13-1

Minimally Invasive Surgery for Skull Base Tumors

The Jefferson Center for Minimally Invasive Cranial Base Surgery and Endoscopic Neurosurgery reflects three of the current evolutions in neurological surgery. The first of these is reflected in the name of the Center itself. Surgical Procedures, Minimally Invasive, a Medline Subject Heading since 1998, is defined as: Procedures that avoid use of open invasive surgery in favor of closed or local surgery. These generally involve use of laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device. With the reduced trauma associated with minimally invasive surgery, long hospital stays may be reduced with increased rates of short stay or day surgery. Traditionally, cranial base tumors have been removed by making craniotomies or cranial base ostomies, and possibly by removing facial bones. To access these areas, surgeons usually need to make potentially disfiguring incisions in the face and scalp. Sometimes the morbidity from the “open” cranial base approach alone could be significant, even with an uneventful removal of the tumor. At the Center, the endoscopic approaches are usually through the nose or nasal passages (Figure 1), however transoral endoscopic approaches to the cranial base and cervical spine are also performed. Because morbidity from the minimally invasive endoscopic approaches is so low, it becomes possible to treat patients with tumors that were previously considered non-resectable or as having too poor a prognosis for more invasive surgery. Even partial resection of such tumors can relieve pain, preserve function, and permit earlier adjuvant radiation and chemotherapy

NUT Midline Carcinoma in a Pregnant Woman

NUT midline carcinoma is a rare, highly aggressive tumor that involves midline structures, particularly in the head, neck and mediastinum. It is characterized by NUT gene translocations on chromosome 15. It typically impacts teenagers or young adults, and has a fulminant course leading to death in less than a year in most cases despite aggressive chemoradiotherapy. Due to its location, this tumor is frequently considered inoperable. We present a case of a sinonasal NUT midline carcinoma with orbital invasion discovered during the workup of sinusitis in a young, pregnant woman. The tumor was managed with definitive excision to negative margins followed by aggressive chemoradiation, with no evidence of recurrence for 12 months. We propose that diagnosis of NUT midline carcinoma should prompt recognition of the limitations of current medical therapy and rapid surgical intervention should be undertaken when possible

Phase I Study of Ipilimumab Combined with Whole Brain Radiation Therapy or Radiosurgery for Melanoma Patients with Brain Metastases

Purpose: We performed a phase I study to determine the maximum tolerable dose (MTD) and safety of ipilimumab with stereotactic radiosurgery (SRS) or whole brain radiotherapy (WBRT) in patients with brain metastases (BM) from melanoma. Methods: Based on intracranial (IC) disease burden, patients were treated with WBRT (Arm A) or SRS (Arm B). Ipilimumab starting dose was 3 mg/kg (every 3 weeks, starting on day 3 of WBRT or 2 days after SRS). Ipilimumab was escalated to 10 mg/kg using a two-stage, 3+3 design. The primary endpoint was to determine the MTD of ipilimumab combined with radiotherapy. Secondary endpoints were overall survival (OS), IC and extracranial (EC) control, progression free survival (PFS), and toxicity. This trial is regis- tered with ClinicalTrials.gov, number NCT01703507. Results: Characteristics of the 16 patients enrolled between 2011 and 2014 were: mean age, 60; median BM, 2 (1 to \u3e10); number with EC disease, 13 (81%). Treatment included WBRT (n=5), SRS (n=11), ipilimumab 3mg/kg (n=7), 10 mg/kg (n=9). Median follow-up was 8 months (Arm A) and 10.5 months (Arm B). There were 21 grade 1-2 neuro- toxic effects with no dose-limiting toxicities (DLTs). One patient experienced grade 3 neurotoxicity prior to ipilimumab administration. Ten additional grade 3 toxicities were reported with gastrointestinal (n=5, 31%) as the most common. There were no grade 4/5 toxicities. Median PFS and OS, respectively, in Arm A were 2.5 months and 8 months, and in Arm B were 2.1 months and not reached. Conclusion: Concurrent ipilimumab 10 mg/kg with SRS is safe. The WBRT arm was closed early due to slow accrual, but demonstrated safety with ipilimumab 3 mg/kg. No patient experienced DLT. Larger studies with ipilimumab 10 mg/kg and SRS are warranted

NEUCOMP2 - parallel neural network compiler

A parallel neural network compiler (NEUCOMP2) for a shared-memory parallel machine has been implemented by introducing parallelism in NEUCOMP. The parallel routine detects the program loops of the sequential version generated by NEUCOMP, undergoing analysis of the data dependences and transforms it into a parallel version. Experiments were carried out to study the performance of the NEUCOMP2 programs for the backpropagation network. NEUCOMP2 was developed and run on the Sequent Balance 8000 computer system at Parallel Algorithm Research Centre, U.K