A Novel Inextensible Endoscopic Tube Versus Traditional Extensible Retractor System in Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Prospective Observation Study.

BACKGROUND: Currently, various retractor systems are widely used for access to the lumbar spine in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Nevertheless, studies concerning the comparison of extensible retractor and inextensible tube systems are quite rare. OBJECTIVES: This article was to compare perioperative characteristics, clinical outcomes, and multifidus muscle injury of obconic inextensible tube versus extensible retractor system for single-level MIS-TLIF. STUDY DESIGN: A prospective observational study on 91 patients with a mean follow-up of 20.0 ± 4.1 months. SETTING: This study was conducted by a university-affiliated hospital in a major Chinese city. METHODS: From April 2015 to May 2016, 91 consecutive patients who underwent MIS-TLIF procedure using an obconic inextensible endoscopic tube or extensible retractor system were enrolled in this study. Operation parameters such as incision length, blood loss, postoperative drainage volume, surgical time, analgesic use rate, time to ambulation, and postoperative hospitalization days were evaluated. The concentration of white blood cells, interleukin-6, interleukin-8, tumor necrosis factor alpha, and creatine phosphokinase (CPK)-MM of the enrolled patients were measured for postoperative traumatic stress and muscle injury. Multifidus muscle edema and atrophy were evaluated by T2-weighted magnetic resonance imaging (MRI) at 3 different time points (preoperative, postoperative, and 1-year follow-up). Clinical outcomes such as Visual Analog Scale (VAS) score, Japanese Orthopedic Association (JOA) score, Oswestry Disability Index (ODI) score, fusion rates, and MacNab criteria were assessed for patients' symptoms. RESULTS: In terms of baseline characteristics, the 2 groups were similar regarding sample size, gender, age, symptoms duration, operation level, body mass index, physical examination, and all the clinical outcomes measures (P > 0.05). Perioperative analysis showed that the inextensible group had comparative incision length, blood loss, operation time, time to ambulation, and postoperative hospitalization (P > 0.05). The inextensible tubular group had less postoperative drainage volume and analgesic use rate (P < 0.05). The concentration level of CPK-MM and c-reactive protein (CRP) was lower in the inextensible tubular group compared with the extensible retractor group.No significant difference was found between the 2 groups regarding MRI T2 signal intensity ratio of multifidus muscle at the immediate postoperative period. The MRI T2 signal intensity ratio of multifidus muscle was lower in the inextensible tubular group than the extensible retractor group at the 1-year follow-up period. The VAS scores for low back pain and leg pain improved significantly in both groups after surgery, as did the JOA and ODI scores. However, there were no significant differences between the 2 groups regarding the preoperative and final follow-up VAS, JOA, and ODI scores, fusion rates, and the distribution of the MacNab criteria. LIMITATIONS: This was not a randomized controlled trail, which could provide more evidence-based medicine conclusions. CONCLUSIONS: The obconic inextensible endoscopic tube system via the transforaminal approach for lumbar interbody fusion is a safe and sufficient technique. When compared with the extensible retractor system, it has comparable clinical outcomes, with additional significant benefits of less postoperative drainage volume and analgesic use rate, less multifidus muscle injury in terms of lower CPK-MM levels at immediate postoperative period, less change in CRP, and less change in MRI T2 signal intensity ratio of multifidus muscles at 1-year follow-up. KEY WORDS: Minimally invasive, endoscopic, lumbar interbody fusion, tubular, multifidus muscle.

A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes.

OBJECTIVE Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments-a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)-is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy. METHODS A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig. RESULTS Testing in porcine brains confirmed the multiport endoscope's ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device's utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°. CONCLUSIONS The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy.

Post-purchase reassessment and improvement of neuroendoscope holder: importance of physician-manufacturer communication.

BACKGROUND: Modern medical management requires constant quality improvement of the various instruments used for surgical procedures. Higher quality, less complicated handling, and reduced maintenance are all desirable qualities. However, any improvements in instrumentation require that surgeons must clearly understand the application of the device by adherence to the manufacturer's instructions. The weakness of this one-way information flow depends on the low interest among medical personnel for post-purchase reassessment. OBJECTIVE: Service industries have research departments to investigate the post-purchase behavior of customers, and service recovery is considered essential to retain customers after service failure. All service providers can suffer service failures, and even the best providers may make errors in delivering service. Such an approach has been increasingly adopted in the risk management at medical institutions. METHODS: We report our clinical trials of the post-purchase reassessment and product improvement of surgical instrumentation. Medical personnel reassessed the use of a newly developed endoscope holder based on the manufacturer's manual and made recommendations for possible improvements, which were examined by the manufacturer. RESULTS: Simple but important improvement was achieved for reducing the instability and uncertainty of instrument fixation. CONCLUSION: This bi-directional post-purchase communication between medical personnel and manufacturers can improve risk management in medical institutions.

Transventricular fenestration of the lamina terminalis: the value of a flexible endoscope: technical note.

BACKGROUND: Recently, the authors demonstrated the technical feasibility of a transventricular translaminar terminalis ventriculostomy with a rigid endoscope. A major problem with this technique remains the contusion of the fornix at the foramen of Monro. Here, the authors evaluated alternative approaches and techniques, including the use of a flexible endoscope. MATERIAL AND METHODS: Feasibility of two approaches-anterior and posterior of the coronal suture-was evaluated on magnetic resonance images and in cadaveric brains. Two different trajectories were selected. Lamina terminalis (LT) fenestration was performed with a rigid and a flexible endoscope using two approaches in 10 fixed cadaver brains. RESULTS: Using the posterior approach 2 cm behind the coronal suture with the two endoscopes caused moderate to severe damage to foramen and fornix. Using the standard approach (Kocher point) with the flexible endoscope avoided damage of these structures. After completion of the anatomical investigation, the authors successfully performed a transventricular fenestration of the LT with the flexible endoscope in one clinical case. CONCLUSION: Rigid scopes provide brilliant optics and safe manipulation with the instruments. However, with the rigid scope, a transventricular opening of the LT is only possible with acceptance of structural damage to the foramen of Monro and the fornix. In contrast, opening of the LT via a transventricular route with preservation of the anatomical structures can be achieved with a flexible steerable endoscope even via a standard burr hole. Thus, if a standard third ventriculostomy is not feasible, endoscopic opening of the LT might represent an alternative, particularly with a flexible scope in experienced hands.

Newly developed electromagnetic tracked flexible neuroendoscope.

Flexible endoscopes can be used in areas that are difficult to approach using rigid endoscopes. No current real-time navigation systems identify the tip of the flexible neuroendoscope. We have developed a flexible neuroendoscope mounted with a magnetic field sensor tip position-tracking system and evaluated the accuracy of this magnetic field neuronavigation system. Based on an existing flexible neuroendoscope, we created a prototype with a built-in magnetic field sensor in the tip. A magnetic field measurement device provides a magnetic field with a working volume of 500 × 500 × 500 mm in front of the device. The device consists of a flat field generator that creates a pulsed magnetic field, connected to a system control unit that interfaces with a computer. The magnetic field sensor (1.8 × 9 mm) was sealed in a site 0.9 mm from the endoscope tip. Accuracy of neuroendoscope tracking was measured using a three-dimensional coordinate-measuring machine that measures the position of objects along 3 axes, with an error of about 3 µm. The accuracy for this neuroendoscope with built-in magnetic field sensor was root mean square error of 1.2 mm and standard deviation of 0.5 mm. This magnetic field neuronavigation system enables real-time tracking of the tip of the flexible neuroendoscope. Application of this flexible neuroendoscope to intraoperative navigation appears promising, and may provide new advantages for minimally invasive endoscopic surgery.