OBJECTIVE: The risk of musculoskeletal injuries (MSIs) increases over years of practice which may lead to career-ending among surgeons. Exoscopes represent a new generation of imaging systems that help surgeons operate in a more comfortable posture. This article aimed to assess advantages and limitations, especially ergonomics with a 3D exoscope in lumbar spine microsurgery versus an operating microscope (OM) to reduce MSIs.
METHODS: From March 2018 to May 2020, 90 patients with lumbar disc herniation undergoing a single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedure were included. Forty-seven patients were operated with the assistance of the exoscope and 43 patients were operated with the assistance of the OM. Clinical data, magnification, and illumination were evaluated. In particular, the ergonomics of surgeons was evaluated by a questionnaire (subjective) and a rapid entire body assessment (REBA; objective).
RESULTS: The postoperative outcomes were reasonably well balanced between the two groups. The handling of the exoscope was comparable to that of the OM. The depth perception, image quality, and illumination of the exoscope were inferior to those of the OM in MIS-TLIF with long and deep approaches. The educational and training function of the exoscope was superior to that of the OM. Importantly, surgeons rated the ergonomics of the exoscope as very high on the questionnaire and the REBA to the OM (P = 0.017).
CONCLUSIONS: This study showed that the exoscope was a safe and effective alternative to the OM for assisting the MIS-TLIF procedure with the unique advantage of ergonomics to reduce musculoskeletal injuries.

OBJECTIVE: The operative microscope (OM) has revolutionized the field of modern spine surgery, however, it remains limited by several drawbacks. Recently, the exoscope (EX) system has been designed to assistant spine surgery. It provides a three-dimensional (3D) high-definition (HD) operative experience and becomes an alternative to the OM. The aim of the study was to evaluate the clinical outcomes, advantages and limitations of EX-assisted minimally invasive transforaminal lumbar interbody fusion (EMIS-TLIF) and OM-assisted MIS-TLIF (OMIS-TLIF).
METHODS: The clinical outcomes were assessed in 47 patients with lumbar degenerative diseases (LDD) who underwent MIS-TLIF assisted with the OM or EX between January 2019 and September 2020. A total of 22 were treated with EMIS-TLIF, and 25 received OMIS-TLIF. Perioperative parameters (including sex, age, number of fusion levels and body mass index), perioperative parameters (operation time, intraoperative blood loss, postoperative drainage, postoperative hospitalization stay, and duration of follow-up), visual analogue scale (VAS) of back pain, VAS of leg pain, Oswestry disability index (ODI) scores and clinical outcomes were assessed and compared. Image quality, handling of equipment, ergonomics, 3D glasses and educational usefulness were scored according to a questionnaire.
RESULTS: Operation time in the OMIS-TLIF group (121.92 ± 16.92 min) was significantly increased compared with that in the EMIS-TLIF group (111.00 ± 19.87 min) (P < 0.05). The VAS of the back pain and ODI scores in the EMIS-TLIF group were significantly lower compared with the OMIS-TLIF group at 1 week postoperatively (P < 0.05). The good-excellent outcomes rate was 90.91% in the EMIS-TLIF group and 88.00% in the OMIS-TLIF group, and there was no significant difference. A total of 44 visits completed the questionnaire. The results of the questionnaire showed that the EX has exhibited advantages regarding handing of equipment, ergonomics and educational usefulness, and comparable image quality as compared with the OM, however, operating surgeons complained uncomfortable sensation when wearing 3D glasses.
CONCLUSIONS: The EMIS-TLIF was a safe and effective procedure in the management of LDD as compared with the OMIS-LIF. Meanwhile, EMIS-TLIF might resulted in a short operation time.

This article aims to introduce an endoscopic-exoscopic technique for the resection of epidermoid cysts.
We retrospectively analyzed the intracranial epidermoid cysts patients who received whole-course combined endoscopic and exoscopic resection between 2017 and 2020 at our institution, to explore the benefit of combined endoscopic and exoscopic resection of intracranial epidermoid cysts, and evaluated the clinical utility of the endoscopic-exoscopic technique.
A total of 17 patients were enrolled in the study. Of all patients, 6 patients (35.3%) underwent total resection, 10 patients (58.8%) underwent subtotal resection, and 1 patient (5.9%) underwent partial resection. Postoperative surgical complications were seen in 3 patients (17.6%), including intracranial infection in 2 patients (11.8%), and a delayed postoperative hematoma was observed in the seventh day after operation for 1 patient (5.9%), who was treated in a conservative manner and recovered smoothly from the hemorrhage. The median follow-up time was 33.3 months (range: 14.5-54.5 months). During the follow-up period, there was no recurrence of the tumors that received total resection. Two patients developed residual tumor regrowth but did not show any symptoms, therefore no further surgery was required.
Endoscopic-exoscopic technique is safe and efficient in the resection of intracranial epidermoid cysts with panoramic views and superior maneuverability. With further development and accumulation of practical experiences, the endoscopic-exoscopic technique can also be applied in the resection of other intracranial tumors.

A clear, stable, suitably located vision field is essential for port surgery. A scope is usually held by hand or a fixing device. The former yields fatigue and requires lengthy training, while the latter increases inconvenience because of needing to adjust the scope. Thus, the authors innovated a novel robotic system that can recognize the port and automatically place the scope in an optimized position. In this study, the authors executed a preliminary experiment to test this system\'s technical feasibility and accuracy in vitro.
A collaborative robotic (CoBot) system consisting of a mechatronic arm and a 3D camera was developed. With the 3D camera and programmed machine vision, CoBot can search a marker attached to the opening of the surgical port, followed by automatic alignment of the scope\'s axis with the port\'s longitudinal axis so that optimal illumination and visual observation can be achieved. Three tests were conducted. In test 1, the robot positioned a laser range finder attached to the robot\'s arm to align the sheath\'s center axis. The laser successfully passing through two holes in the port sheath\'s central axis defined successful positioning. Researchers recorded the finder\'s readings, demonstrating the actual distance between the finder and the sheath. In test 2, the robot held a high-definition exoscope and relocated it to the setting position. Test 3 was similar to test 2, but a metal holder substituted the robot. Trained neurosurgeons manually adjusted the holder. The manipulation time was recorded. Additionally, a grading system was designed to score each image captured by the exoscope at the setting position, and the scores in the two tests were compared using the rank-sum test.
The CoBot system positioned the finder successfully in all rounds in test 1; the mean height errors ± SD were 1.14 mm ± 0.38 mm (downward) and 1.60 mm ± 0.89 mm (upward). The grading scores of images in tests 2 and 3 were significantly different. Regarding the total score and four subgroups, test 2 showed a more precise, better-positioned, and more stable vision field. The total manipulation time in test 2 was 20 minutes, and for test 3 it was 52 minutes.
The CoBot system successfully acted as a robust scope holding system to provide a stable and optimized surgical view during simulated port surgery, providing further evidence for the substitution of human hands, and leading to a more efficient, user-friendly, and precise operation.

Operative microscope (OM) has greatly advanced modern spine surgery, but remains limited by several drawbacks. Therefore, a three-dimensional (3D) high-definition (HD) exoscope (EX) (Kestrel View II, Mataka Kohli, Japan) system has been developed and used as an alternative to the OM. The aim of this study was to assess and compare the perioperative data and clinical outcomes of anterior cervical discectomy and fusion (ACDF) procedure with either an EX or OM.
Forty-eight patients with cervical spondylotic myelopathy (CSM) underwent ACDF assisted by the EX or OM between January 2019 and December 2019. We collected and compared data on operative time, intraoperative bleeding, postoperative hospitalization stay, complications, and clinical outcomes between the two groups. The clinical outcomes were evaluated by using visual analogue scale (VAS) scores, Japanese Orthopedic Association (JOA) scores, the recovery rate of JOA scores, and Odom criteria.
The operative time in the EX group was significantly shorter than that in the OM group (P < 0.05). The VAS and JOA scores were significantly improved in both groups after surgery (P < 0.05). In addition, the VAS scores in the EX group were significantly lower than those in the OM group at 1 week postoperatively (P < 0.05). The good-to-excellent outcome rates were 90.48 and 88.89% in the EX group and OM group, respectively, whereas the complication occurrence rates of the EX group and OM group were 4.76 and 11.11%, respectively.
EX-assisted and OM-assisted ACDF resulted in similar clinical outcomes for CSM, while EX-assisted surgery may be related to a short operative time and fewer complications.

OBJECTIVE: The aim of this study was to evaluate our experience with a high-definition three-dimensional (3D) exoscope (EX) for cervical spine surgery versus a binocular operating microscope (OM).
METHODS: A retrospective review of patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) procedure for the treatment of cervical myelopathy from March 2019 to May 2020 was performed. Demographic, perioperative, and clinical outcomes of 50 patients were included, 23 of whom received assistance from the 3D exoscope (EX group) and 27 of whom received assistance from the OM (OM group). Operative baseline and postoperative outcome parameters were evaluated. Periprocedural handling, visualization, and illumination by the EX, as well as surgeons\' ergonomics, were scored using a questionnaire and rapid upper limb assessment (RULA).
RESULTS: Baseline characteristics were similar between the two groups. There were no significant differences between groups in mean operative time, blood loss, duration of admission, or postoperative improvement of symptoms. Both groups showed similar clinical improvements after surgery. There were no intraoperative complications in either group. According to the attending surgeons, the intraoperative handling of instruments for the EX was rated to be comparable to that of the OM. Surgeons rated the comfort level of the intraoperative posture for the EX as very high on the subjective questionnaire and equal to the OM on the objective RULA. When compared with the OM, depth perception, image quality, and illumination for the EX were rated as inferior in ACDF procedures with long approaches. The operative education and training function of the EX was rated to be superior to that of the OM.
CONCLUSIONS: Overall, our study showed that the EX appears to be a safe alternative for common ACDF with the unique advantage of excellent comfort and also serves a useful educational tool for the surgical team. However, our investigation revealed several important limitations of this system, including slightly inferior visualization and illumination quality compared with the OM.