Clinical Application of a High Definition Three-Dimensional Exoscope in Anterior Lumbar Interbody Fusion: Technical Note

Abstract

Objectives: Video-assisted telescope operating monitor (VITOM) or exoscope is currently applied in different surgical specialties with clear visualization advantages in terms of magnification, illumination, and wide field of view. The small and deep surgical field of anterior lumbar interbody fusion (ALIF) seemed to be an ideal setting to assess efficacy of exoscope, also considering limits related to microscopic and endoscopic visualization currently employed.

Methods: We reported our preliminary experience with exoscope in 9 cases of ALIF at L5-S1 level. These data were retrospectively compared with those obtained from an equal sample of ALIF procedures performed with endoscope as visualization instrument. The technical aspects taken into account were time for procedure and blood loss. Reports from the surgeon about ergonomics and confidence with both techniques were also evaluated.

Results: Exoscope proved, in our experience, good visualization and ergonomics and unobstructed access to a small and deep surgical field, allowing abundant space to insert and manipulate the instruments.

Conclusions: The instrument contained dimension and its long working distance, superior to endoscope and comparable with operating microscope, showed clear advantages of maneuverability. Moreover, the stereoscopic vision provided by 3-dimensional images proved to be crucial in hand-eye coordination.

Keywords: anterior lumbar interbody fusion; exoscopy; minimally invasive spine surgery; video-assisted telescope operating monitor.

Figure 1

Surgical exposure of anterior lumbosacral spine is obtained through a skin incision in lower abdominal quadrants. Our preliminary experience is based on a linear horizontal skin incision of 6 to 8 cm in length, 5 to 7 cm beneath the umbilicus.

Figure 2

Exoscope video-assisted telescope operating monitor (VITOM) 3D in the operating setting, kept in position by an articulated holding arm, provides an unobstructed working space. The surgical field is displayed on 2 movable 32” 3D monitors positioned on the opposite side of the surgical table respect to surgeon and assistant positions, which are counterposed and wear 3D glasses. Images displayed on the 2 screens are specular to each other to reproduce the intraoperative sight with the correct orientation for each surgeon and ease surgical maneuvers. It is possible to shift from microscopic to macroscopic vision without moving the scope or completely losing microscopic vision, if necessary.

Figure 3

After incision and lateral retraction of anterior longitudinal ligament (A), discectomy and curetting of upper (B1) and lower (B2) endplates is performed under exoscopic magnification. The intervertebral space (C) is then prepared for insertion of the cage.

Figure 4

L5-S1 anterior lumbar interbody fusion (ALIF): X-rays presurgery (A) and postsurgery (B). Anterior access to the intervertebral space allows an easier insertion of angulated cages, when compared with posterior approaches, thus generating a satisfactory restoration of lumbar lordosis and spino-pelvic balance. Moreover, the restoration of disc height obtains increase of neuroforaminal volume and consequent relief of radicular symptoms due to indirect decompression.