The endonasal patient reference tracker: a novel solution for accurate noninvasive electromagnetic neuronavigation.

OBJECTIVE: Electromagnetic (EM) navigation provides the advantages of continuous guidance and tip-tracking of instruments. The current solutions for patient reference trackers are suboptimal, as they are either invasively screwed to the bone or less accurate if attached to the skin. The authors present a novel EM reference method with the tracker rigidly but not invasively positioned inside the nasal cavity. METHODS: The nasal tracker (NT) consists of the EM coil array of the AxiEM tracker plugged into a nasal tamponade, which is then inserted into the inferior nasal meatus. Initially, a proof-of-concept study was performed on two cadaveric skull bases. The stability of the NT was assessed in simulated surgical situations, for example, prone, supine, and lateral patient positioning and skin traction. A deviation ≤ 2 mm was judged sufficiently accurate for clinical trial. Thus, a feasibility study was performed in the clinical setting. Positional changes of the NT and a standard skin-adhesive tracker (ST) relative to a ground-truth reference tracker were recorded throughout routine surgical procedures. The accuracy of the NT and ST was compared at different stages of surgery. RESULTS: Ex vivo, the NT proved to be highly stable in all simulated surgical situations (median deviation 0.4 mm, range 0.0-2.0 mm). In 13 routine clinical cases, the NT was significantly more stable than the ST (median deviation at procedure end 1.3 mm, range 0.5-3.0 mm vs 4.0 mm, range 1.2-11.2 mm, p = 0.002). The loss of accuracy of the ST was highest during draping and flap fixation. CONCLUSIONS: Application of the EM endonasal patient tracker was found to be feasible with high procedural stability ex vivo as well as in the clinical setting. This innovation combines the advantages of high precision and noninvasiveness and may, in the future, enhance EM navigation for neurosurgery.

Surgical Management of Familial Trigeminal Neuralgia With Different Inheritance Patterns: A Case Report.

INTRODUCTION: Trigeminal neuralgia is a disorder characterized by unilateral electric shock-like pain, distributed in one or more trigeminal nerve branches and triggered by usually innocuous stimuli. Among the few case reports and literature reviews on familial trigeminal neuralgia (FTN), the results of several suggest the involvement of genes associated with biochemical alterations or atherosclerotic vascular malformations. BACKGROUND: We present four cases of FTN within two families (family A: two brothers; family B: two sisters). All patients were submitted to surgical treatment by the same surgeon. DISCUSSION: Cases 1 and 2 (family A) exhibited FTN with an uncommon autosomal recessive pattern and clinical features consistent with previous literature reviews and case reports. However, in cases 3 and 4 (family B), we found FTN with a dominant autosomal pattern and an unusual physiopathology characterized by arachnoid adhesions. CONCLUSION: We conclude, in this case report, that there are several inheritance patterns as well as physiopathology that may be involved in FTN, and that both patterns described in our reported cases were successfully managed with surgery.

[The woman in neurosurgery at the national institute of neurology and neurosurgery]. / La mujer en neurocirugía en el Instituto Nacional de Neurología y Neurocirugía (INNN).

Women have always had a hard time in the history of medicine; Dr. Isabel Blackwell was the first woman in history to practice medicine. Dr. Diana Beck became the world´s first female neurosurgeon. The first Latin American female neurosurgeon was Dr. María Cristina García Sancho y Álvarez-Tostado. All of these women had to face a large number of social, cultural, and economic obstacles in their path; however, this situation has changed gradually. Dr. Ana Lilia Siordia Karam was the first neurosurgeon to graduate from INNN. Nineteen years later the second female neurosurgeon at this institute was Dr. María Petra Herrera Guerrero. During their time at this institute they endured a lot of difficulties, especially with most of their coworkers; however, some coworkers treated them with respect and no gender distinction. Nowadays, four of the 25 total neurosurgery residents at INNN are women, and even though some of them have had to endure acts of gender discrimination, the general situation has changed. With work and respect, women have managed to have a larger role in the surgical field. We hope that in the near future a gender discrimination-free environment will be achieved in medicine and its specialties.