Early Experience with New High Definition Three-Dimensional (HD3D) Neuroendoscopy

Introduction: The endoscope has revolutionized anterior skull base surgery in the past 20+ years, allowing endonasal approaches to tackle increasingly complex lesions that previously would have required craniotomy. Increasingly, the endoscope is being used for minimally invasive approaches to other regions within the cranial vault, including the middle and posterior fossas, by allowing improved visualization and limited retraction while preserving use of traditional microdissection techniques. One major drawback of endoscopes compared with traditional operating microscopes is the lack of stereoscopic vision and the resulting difficulties in depth perception. Though three-dimensional (3D) endoscopes have been available for many years, existing 3D endoscopes had significantly reduced image quality compared with modern High Definition (HD2D) endoscopes. A new endoscope has recently received FDA approval that offers HD3D optics. We report on our initial surgical experience using this new endoscope.

Methods: We used the HD3D endoscope in 6 cases at the University of Pennsylvania from June to August 2013. All cases were performed with 4mm outer diameter VSiii3 HD3D endoscopes (Visionsense; New York, NY). Both wide and standard field of view models were used.

For posterior fossa surgeries the Point Setter pneumatic arm (Mitaka USA; Park City, UT) was used to hold the endoscope, which was periodically removed to clean the endoscope and release retraction on the cerebellum. For endonasal and intraventricular surgeries no scope holder was used.

A Storz HD endoscope (Karl Storz; Tuttlingen, Germany) was available as needed.

Results: The HD3D scope was used in 6 cases: (1) a pituitary macroadenoma resected via endonasal approach, (2) a supraorbital keyhole approach via eyebrow incision for resideual/recurrent suprasellar macroadenoma compressing the left optic nerve, (3) an endoscopic third ventriculostomy, (4–5) two microvascular decompressions for trigeminal neuralgia, and (6) a vestibular schwannoma via retrosigmoid approach.

The HD3D endoscope was used for the critical portion of the procedure in all cases, and in all cases the HD3D endoscope offered improved depth perception and ease of microdissection compared with standard 2D endoscopy. Color and clarity were excellent and side-by-side comparisons appeared comparable to standard HD2D optics.

Compared with the 2D endoscope, the HD3D endoscope was somewhat more technically challenging to use in the posterior fossa, as these approaches are performed through a 10mm diameter dural opening and the slightly larger outer diameter of the HD3D endoscope required slightly more cerebellar retraction in the initial arachnoid dissection. All surgeries were successful and there were no intraoperative complications.

Conclusion: The HD3D endoscope can be used for a variety of neurosurgical pathologies and improves depth perception and ease of microdissection compared with standard 2D endoscopy. The size of the endoscope (4mm outer diameter) is ideal for most neurosurgical applications, however may present some technical challenges when working in the posterior fossa compared with 2.7mm 2D endoscopes. Overall the HD3D endoscope allows comparable color and clarity to HD2D scopes and has very little associated learning curve for surgeons facile with endoscopic approaches.