Novel MIS 3D NAV Single Step Pedicle Screw System (SSPSS): Workflow, Accuracy and Initial Clinical Experience

STUDY DESIGN

Prospective case series.

OBJECTIVE

SSPSS (single step pedicle screw system) was developed for minimally invasive spine surgery. We performed this study to report on safety, workflow, and our initial clinical experience with this novel technique.

METHODS

The prospective study was conducted on patients who underwent pedicle screw fixation between October 2017 and April 2018 using a novel single step 3D navigated pedicle screw system for MIS. Outcome measurements were obtained from intraoperative computerized tomography. The images were evaluated to determine pedicle wall penetration. We used a grading system to assess the severity of the pedicle wall penetration. Breaches were classified as grade 1 (<2 mm), grade 2 (2-4 mm), or grade 3 (<4 mm),¹ and as cranial, caudal, medial, and lateral.

RESULTS

Our study includes 135 screws in 24 patients. SSPSS eliminated K-wires and multiple steps traditionally necessary for MIS pedicle screw insertion. The median time per screw was 2.45 minutes. 3 screws were corrected intraoperatively. Pedicle wall penetration occurred in 14 screws (10%). Grade 1 breaches occurred in 4 screws (3%) and grade 2 breaches occurred in 10 screws (7%). Lateral breaches were observed more often than medial breaches. The accuracy rate in our study was 90% (Grade 0 breach). No revision surgeries were needed and no complications occurred.

CONCLUSIONS

Our study suggests that SSPSS could be a safe, accurate, and efficient tool. Our accuracy rate is comparable to that found in the literature.

Ten-Step Minimally Invasive Cervical Decompression via Unilateral Tubular Laminotomy: Technical Note and Early Clinical Experience

BACKGROUND

Minimally invasive techniques utilizing tubular retractors have become an increasingly popular approach to the spinal column. The concept of a unilateral laminotomy for bilateral decompression (ULBD), first applied in the lumbar spine, has recently been applied to the cervical spine for the treatment of cervical spondylotic myelopathy (CSM). A better understanding of the indications and surgical techniques is required to effectively educate surgeons on how to appropriately and safely perform tubular cervical laminotomy via ULBD.

OBJECTIVE

To describe a 10-step technique for minimally invasive cervical laminotomy and report our early clinical experience.

METHODS

A retrospective review identified 15 patients with CSM who were treated with this procedure. Visual analogue scale (VAS), neck disability index (NDI), and modified Japanese Orthopaedic Association (mJOA) scores were obtained pre- and postoperatively.

RESULTS

The mean age of the 15 patients was 73.1 ± 6.8 yr. The median number of levels treated was 1 (range 1-3). Mean operative time was 125.3 ± 30.8 or 81.7 ± 19.2 min per level. Mean estimated blood loss was 57.3 ± 24.6 cc. Median postoperative hospital length of stay was 36 h. No complications were encountered. Median follow-up was 18 mo. Mean pre- and postoperative VAS were 6.4 ± 2.4 and 1.0 ± 0.8, respectively (P < .001). Mean pre- and postoperative NDI were 46.4 ± 19.2 and 7.0 ± 6.9, respectively (P < .001). Mean pre- and postoperative Mjoa were 11.3 ± 2.5 and 14.5 ± 0.5, respectively (P < .001).

CONCLUSION

In our early clinical experience, minimally invasive cervical ULBD is safe and effective. Adherence to the presented 10-step technique will allow surgeons to safely address bilateral cervical pathology while avoiding complications.

Indirect Decompression Failure After Lateral Lumbar Interbody Fusion-Reported Failures and Predictive Factors: Systematic Review

BACKGROUND

In patients with symptomatic lumbar stenosis undergoing lateral transpsoas approach for lumbar interbody fusion (LLIF) surgery, it is not always clear when indirect decompression is sufficient in order to achieve symptom resolution. Indirect decompression failure (IDF), defined as "postoperative persistent symptoms of nerve compression with or without a second direct decompression surgery to reach adequate symptom resolution," is not widely reported. This information, however, is critical to better understand the indications, the potential, and the limitations of indirect decompression.

OBJECTIVE

The purpose of this study was to systematically review the current literature on IDF after LLIF.

METHODS

A literature search was performed on PubMed. We included randomized controlled trials and prospective, retrospective, case-control studies, and case reports. Information on sample size, demographics, procedure, number and location of involved levels, follow-up time, and complications were extracted.

RESULTS

After applying the exclusion criteria, we included 9 of the 268 screened articles that reported failure. A total of 632 patients were screened in these articles and detailed information was provided. Average follow-up time was 21 months. Overall reported incidence of IDF was 9%.

CONCLUSION

Failures of decompression via LLIF are inconsistently reported and the incidence is approximately 9%. IDF failure in LLIF may be underreported or misinterpreted as a complication. We propose to include the term "IDF" as described in this article to differentiate them from complications for future studies. A better understanding of why IDF occurs will allow surgeons to better plan surgical intervention and will avoid revision surgery.