Grade II Spondylolisthesis: Reverse Bohlman Procedure with Transdiscal S1-L5 and S2 Alar Iliac Screws Placed with Robotic Guidance

Sacrolumbar Interbody Fusion (SLIF): Feasibility, Technical Nuances, Biomechanical Assessment, and Clinical Outcomes

Introduction

S1-L5 transdiscal screw fixation is a direct stabilization technique used for surgical treatment of high-grade (III-IV) L5-S1 spondylolisthesis. It has not been used for nonspondylolisthetic cases or in combination with an interbody cage (IC). This study aimed to develop a novel, direct S1-L5 sacrolumbar interbody fusion (SLIF) technique, a combination of IC and sacrolumbar transdiscal screw.

Methods

SLIF was tested in cadaveric, clinical, and finite element analysis settings. Three cadaveric lumbar spines were used to test the SLIF procedure before clinical application. Eight patients underwent the SLIF procedure. Clinical outcomes were evaluated by visual analog score for leg and back pain, short form 36, Oswestry disability index, and neurological examination. CT scans of the lumbar spine were used to assess the hardware placement and subsequent fusion. Finite element analysis was performed on a healthy human CT-based L5-S1 model. Intact segment, unilateral facetectomy and discectomy, SLIF, and transforaminal lumbar interbody fusion (TLIF) procedures were compared in terms of the range of motion (ROM), von Mises stress on hardware, and shear-induced directional deformity. Additionally, the same set of tests were conducted in an osteoporotic model.

Results

Excellent hardware placement was feasible in three cadavers and eight patients. Preoperative neurological deficits improved in all patients. Statistically significant improvements were obtained on all self-reported questionnaire scores. All patients developed solid, Bridwell grade I fusions. Biomechanical testing revealed similar outcomes for TLIF and SLIF regarding the ROM. However, the screw's von Mises stress and shear-induced directional deformity were low for SLIF of healthy and osteoporotic bone.

Conclusions

SLIF is a feasible, safe, and effective L5-S1 fusion option suitable for all clinical scenarios. It provides several biomechanical advantages, yielding excellent clinical outcomes.

Transdiscal Screw Fixation in L5-S1 Adult Spondylolisthesis: Technical Note and Midterm Outcomes of a Case Series

BACKGROUND

Spondylolisthesis changes the pelvic morphology and sagittal spinopelvic alignment with abnormality compared to individuals with similar pelvic morphology. There are many treatment options including a combination of decompression and fusion. In spondylolisthesis patients with high-grade spondylolisthesis, bone to bone contact (closed intradiscal space), and high-grade disc degeneration with disc collapse, fusion is challenging.

METHODS

From 2011 through 2020, an analysis of L5-S1 spondylolisthesis patients who had L5-S1 transdiscal screw fixation with a minimum follow-up of 2 years was performed. Radiological evaluation and clinical measures were compared preoperatively and postoperatively. Postoperative complications were analyzed. Also, L5-S1 degree fusion was analyzed using a computed tomography scan.

RESULTS

Eight patients of L5-S1 spondylolisthesis with a mean follow-up of 69 (25-122) months. All patients were female; the average age was 58 (43-78) years. 4 patients presented with high-grade spondylolisthesis (Meyerding grade III). Among the patients, 3 patients were undergoing revision surgery. Only 5 patients had interbody fusion for their adjacent levels. In the postoperative follow-up, none of the patients had neurological deficits. Radiological evaluations of L5-S1 level showed fusion in all patients. Only 1 patient had rod failure and was advised for revision surgery.

CONCLUSIONS

L5-S1 transdiscal screw fixation may provide a satisfactory rigid fixation and fusion at the L5-S1 level in cases of spondylolisthesis. This technique requires a surgeon's experience. Despite the challenge of this technique, it can provide a safe option for acquiring rigid stabilization.

Efficacy of Reverse and Modified Bohlman Technique for Lumbar Spondylolisthesis: A Systematic Review of the Literature

OBJECTIVE

High grade lumbar spondylolisthesis (HGLS) remains a challenging surgical entity, and there is no current consensus regarding optimal surgical approach. The purpose of this study was to systematically review the literature for studies utilizing the Reverse or Modified Bohlman technique for the treatment of HGLS to assess its safety and efficacy.

METHODS

The authors perform a literature search of PubMed/MEDLINE electronic databases from their inception according to the PRISMA guidelines.

RESULTS

A total of 8 studies were included. The studies comprised a total of 43 patients, with mean age of 41.4 ± 19.8 (9-83) years. The mean follow-up was 38.2 ± 41.7 (3-137) months. Most patients (81.4%) were classified as having grade III or higher spondylolisthesis. The most common presenting symptom was back pain (93%), followed by radiculopathy in roughly half of patients (41.9%). Majority of patients (93%) experienced complete resolution of symptoms as well as successful fusion (90.7%) on follow-up. Complications included cage/graft failure (7%), nerve injury (7%), wound infection (7%), pseudoarthrosis (2.3%), epidural hematoma (2.3%), and deep vein thrombosis (2.3%). Revision surgery was required in 4 (9.3%) patients. Slip percentage (60.2% versus 43.2%, p<0.0001) and slip angle (17.1° versus 6.4°, p<0.001) both decreased significantly following surgery.

CONCLUSIONS

Our data demonstrate Reverse and Modified Bohlman techniques appear to be effective in both improving slip angle/percentage and relieving symptoms with low risk of complications. These findings are limited by the small sample size of patients. The authors recommend larger series before formal recommendations can be made.

Use of L5-S1 transdiscal screws in the treatment of isthmic spondylolisthesis: a technical note

Surgical treatment of L5-S1 isthmic spondylolisthesis consists of a combination of decompression and fusion. One previously discussed mode of fusion is via transdiscal screws. Biomechanical studies of transdiscal screws have demonstrated greater rigidity than traditional pedicle screw fixation, which theoretically translates to a higher fusion rate. Furthermore, when compared to pedicle screw fixation, transdiscal screw fixation also demonstrates improved functional and radiographic outcomes. However, transdiscal screw placement can be technically difficult. At this time, a detailed surgical technique has yet to be reported in the literature. Our surgical technique for transdiscal screw placement using intraoperative C-arm at L5-S1 is described. We include considerations for preoperative planning including necessary imaging and appropriate patient selection. We also discuss intraoperative concerns such as setup, surgical approach, proper screw trajectory, and our method for achieving indirect decompression. The results of thirteen consecutive patients treated with transdiscal screw fixation are described. One patient had subcutaneous seroma requiring reoperation (7.7%), three patients had implant failure (23.1%), and one patient had nonunion (7.7%). Our results suggest that transdiscal screw fixation is a safe and acceptable alternative for stabilization and indirect decompression of L5-S1 isthmic spondylolisthesis. Recent innovation in intraoperative navigation and robotic surgery may lessen the technical difficulty of transdiscal screw placement and make it even more effective.

Long term outcome and fusion rate of transdiscal fixation for L5-S1 high grade spondylolisthesis

OBJECTIVE

High grade spondylolisthesis (HGS) is a quite rare entity and many techniques are available to address this condition. In 1994 Abdu et al. proposed a transdiscal fixation approach that achieved a good clinical outcome. We analyse outcome and fusion achieved in patients treated by transdiscal fixation after 1-year follow-up.

METHODS

We reviewed patients operated through transdiscal fixation since 2014 with a follow-up of at least 1 year, and compared preoperative and postoperative clinical measures (ODI, VAS and EQ-5D) and postoperative complications. Also, we analyzed the degree of fusion on CT scan with Lenke and Birdwell criteria.

RESULTS

Twelve patients were included in the study with a mean follow-up of 49.4 months (range 12.8-84.1 months). Three cases presented a Meyerding grade IV spondylolisthesis and 9 cases grade III. At 1-year follow-up mean postoperative ODI, VAS and EQ5D scores improved (ODI 13.2 (range 0-30) vs 49.83 (range 15-71.1); p = .005). Equally this improvement was seen in the last follow-up (ODI 9.28 (range 0-35) vs 49.83 (range 15-71.1); p = .005). CT scan showed fusion grade A in 5 patients (41.6%), another 5 as grade B (41.6%) in Lenke classification. According to the Birdwell criteria 4 patients were classified as grade I (33.3%), 7 patients grade II (58.3%). None showed complications postoperatively or radiolucency in follow-up.

CONCLUSIONS

Transdiscal fixation shows a good clinical outcome that is maintained throughout a long time period and provides a reliable and suitable fusion.