Modified far lateral endoscopic transforaminal lumbar interbody fusion using a biportal endoscopic approach: technical report and preliminary results.

BACKGROUND: Endoscopic transforaminal lumbar interbody fusion (TLIF) has the disadvantage of the small cage size and by consequence risk for cage subsidence. We succeeded to insert a large oblique lumbar interbody fusion (OLIF) cage during biportal endoscopic TLIF. METHODS: Unilateral total facetectomy was performed to expose the exiting and traversing nerve roots. The distance between the exiting and traversing nerve roots was measured before OLIF cage insertion. We inserted an OLIF cage instead of a TLIF cage. CONCLUSION: We successfully performed modified far lateral biportal endoscopic TLIF using large OLIF cages. Modified far lateral biportal endoscopic TLIF is usually suitable for the L4-5 and L5-S1 levels.

Can unilateral-approach minimally invasive transforaminal lumbar interbody fusion attain indirect contralateral decompression? A preliminary report of 66 MRI analysis.

PURPOSE: Few studies have measured the amount of indirect decompression at the contralateral neural foramen after unilateral-approach minimally invasive transforaminal lumbar interbody fusion (MITLIF). This study examined the amount of intraoperative indirect decompression at the contralateral neural foramen after a unilateral-approach MITLIF in patients with bilateral foraminal stenosis. METHODS: From February 2009 to October 2012, 66 consecutive patients with bilateral foraminal stenosis underwent unilateral-approach MITLIF and postoperative magnetic resonance imaging (MRI). Direct decompression was performed at the central canal and approach-side neural foramen, while indirect decompression using cage distraction was pursued at the contralateral neural foramen. Qualitative parameters of the central canal (dural sac morphology) and neural foramen (foramen morphology) were analyzed using pre- and post-operative MRI. Quantitative measurement on the central canal (dural sac cross-sectional area) and neural foramen (foramen height and width) were also measured. RESULTS: A total of 69 intervertebral levels in the 66 patients were analyzed. Qualitative parameters of the central canal and contralateral neural foramen improved significantly after unilateral-approach MITLIF (both P < 0.001). The mean dural sac cross-sectional area increased from 51.1 ± 28.8 to 84.8 ± 30.2 mm(2) (P < 0.001). The mean preoperative contralateral foramen height, maximum foramen width, and minimum foramen width were 11.8 ± 2.0, 4.9 ± 1.5, and 1.5 ± 0.7 mm, respectively, and these values increased postoperatively to 14.7 ± 2.5, 6.5 ± 1.8, and 2.4 ± 1.0 mm, respectively (all P < 0.001). CONCLUSION: Quantitative and qualitative parameters of the central canal and contralateral neural foramen increased significantly after unilateral-approach MITLIF.

Subsidence of polyetheretherketone cage after minimally invasive transforaminal lumbar interbody fusion.

STUDY DESIGN: A retrospective case series. OBJECTIVE: The aim of this study was to determine the rate of cage subsidence after minimally invasive transforaminal lumbar interbody fusion (MITLIF) conducted using a polyetheretherketone (PEEK) cage, and to identify associated risk factors. SUMMARY OF BACKGROUND DATA: Although various rates of cage subsidence after lumbar interbody fusion have been reported, few studies have addressed subsidence rate after MITLIF using PEEK cage. METHODS: A total of 104 consecutive patients who had undergone MITLIF using a PEEK cage with a minimum follow-up of 2 years were included in this study. Cage subsidence was defined to have occurred when a cage was observed to sink into an adjacent vertebral body by ≥2 mm on the postoperative or serial follow-up lateral radiographs. The demographic variables considered to affect cage subsidence were the following: age, sex, body mass index, bone mineral density, diagnosis, number of fusion segment, and the quality/quantity of back muscle, and the cage-related variables considered were: level of fusion, intervertebral angle, cage size, cage position, and postoperative distraction of disc height. Logistic regression analysis was conducted to explore relations between these variables and cage subsidence. RESULTS: : For the 122 cages inserted, the rate of cage subsidence was 14.8% (18 cages), and cage subsidence occurred within 7.2±8.5 (1-25) months of surgery. The odds ratios for factors found to significantly increase the risk of cage subsidence were; 1.950 (95% confidence interval, 1.002-4.224) for L5-S1 level, and 1.018 (95% confidence interval, 1.000-1.066) for anterior cage position. CONCLUSIONS: The rate of PEEK cage subsidence after MITLIF was relatively low. End-plate manipulation and cage insertion during MITLIF were not influenced by a small operation window.

The Future of Minimally Invasive Spine Surgery.

Minimally invasive spine surgery (MISS) is an important option for spinal operations, with advantages including rapid recovery and preservation of normal structures. As the number of geriatric patients is increasing, the role of MISS might expand in the future. MISS techniques and approaches continue to be developed, and recent trends in MISS development include the refinement of surgical approaches and techniques, as well as systems related to newly developed techniques, rather than spinal implants. Among the various techniques for MISS, endoscopic spine surgery, including uniportal and biportal endoscopic approaches, is the focus of vigorous research efforts that may lead to further expansion of the indications of endoscopic spine surgery. Endoscopic spine surgery will be an important part of spine surgery. Lateral lumbar interbody fusion and endoscopic lumbar interbody fusion may play meaningful roles in the MISS fusion area. Robotics and augmented reality are also likely to be important technological modalities in spine surgery in the future.

Surgical Removal of Cervical Extradural Cysts Using the Biportal Endoscopic Approach.

BACKGROUND: Symptomatic intraspinal extradural cysts of the cervical spine are uncommon; however, they are usually treated using conventional posterior decompression. Biportal endoscopic surgery is widely used to treat degenerative cervical pathological conditions. This study presented an optimized surgical technique for a biportal endoscopic posterior approach for removal of cervical intraspinal extradural cysts that caused cervical radiculomyelopathy. METHODS: A broad laminotomy was performed, which was wider than the outer contour of the cysts. The ligamentum flavum was detached from the bony margin and removed after an epidural dissection, and a dense adhesive tissue entrapped the extradural cysts. A spinal endoscope was placed close to the dissection plane and offered a high-resolution magnified view. The cyst capsule was safely dissected from the dura and removed en bloc without dural injury. RESULTS: Postoperatively, neurological deficits, including cervical myelopathy, radiating arm pain, and upper back pain improved in both patients. CONCLUSIONS: We successfully removed an extradural cervical cystic mass lesion by using a biportal endoscopic posterior cervical approach without complications. The biportal endoscopic approach may have advantages, such as minimizing trauma to the normal structures of the posterior cervical region, magnified endoscopic view, and early recovery after the surgery. Biportal endoscopy may be used as an alternative surgical treatment for symptomatic cervical intraspinal extradural cystic lesions.

Indications, Contraindications, and Complications of Biportal Endoscopic Decompressive Surgery for the Treatment of Lumbar Stenosis: A Systematic Review.

BACKGROUND: Biportal endoscopic spine surgery is gaining popularity in managing degenerative lumbar diseases and has optimal indications and contraindications. The perioperative complications related to the biportal endoscopic approach affect the postoperative outcomes. Therefore, this study aimed to review the indications, contraindications, and complications of biportal endoscopic decompression for lumbar stenosis. METHODS: For this systematic review, articles on biportal endoscopic decompressive surgery for lumbar stenosis, including central, lateral recess and foraminal stenoses, were searched for and reviewed. Additionally, the complications, indications, and contraindications of biportal endoscopic surgery for lumbar stenosis were reviewed. RESULTS: Forty-one articles were included in this study. The indications for biportal endoscopic decompression are central lumbar stenosis, central stenosis with lipomatosis, lateral recess stenosis, foraminal stenosis, and the far-out syndrome. The contraindications include trauma, infection, tumor, instability, high-grade spondylolisthesis, isthmic spondylolisthesis, and severe scoliosis. Perioperative complications are typically minor; major complications include durotomy, epidural hematoma, incomplete decompression, infection, facet joint injury, neural injury, increased epidural pressure, and postoperative instability. CONCLUSIONS: Favorable indications for a biportal endoscopic approach are central lumbar, lateral recess, foraminal, extraforaminal stenoses, and the Bertolotti syndrome. Incidental durotomy and postoperative epidural hematomas are common complications of biportal endoscopic decompression.

Clinical Experiences of 3-Dimensional Biportal Endoscopic Spine Surgery for Lumbar Degenerative Disease.

BACKGROUND: The lack of stereoscopic vision in endoscopic spine surgery may lead to a risk of neural or vascular injury during endoscopic surgery. Three-dimensional (3D) endoscopy has not yet been attempted in the field of spinal endoscopic surgery. OBJECTIVE: To present the technique, clinical efficacy, and safety of the 3D biportal endoscopic approach for the treatment of lumbar degenerative disease. METHODS: We attempted 3D biportal endoscopic surgery for lumbar degenerative disease in a series of patients. Clinical outcomes and complications were evaluated postoperatively using a short questionnaire about 3D biportal endoscopic spine surgery that solicited respondents' opinions on the advantages and disadvantages of 3D biportal endoscopic surgery compared to the conventional 2D biportal endoscopic approach. RESULTS: We performed 3D biportal endoscopic spine surgery in 38 patients with lumbar degenerative disease. Optimal neural decompression was revealed by postoperative magnetic resonance imaging in all enrolled patients. The 3D endoscopic vision clearly demonstrated the surgical anatomy starting with the exposure of ligamentum flavum, dura, and nerve root, and 3D endoscopy precisely depicted pathologic lesions such as bony osteophytes and ruptured disc herniation. There were no major complications including neural injury or durotomy. CONCLUSION: The 3D endoscope may be able to distinguish between normal structures and lesions. The stereognosis and depth sensation of 3D biportal endoscopic spinal surgery might have a favorable impact on the safety of patients during endoscopic spine surgery.

Factors affecting the accurate placement of percutaneous pedicle screws during minimally invasive transforaminal lumbar interbody fusion.

We retrospectively evaluated 488 percutaneous pedicle screws in 110 consecutive patients that had undergone minimally invasive transforaminal lumbar interbody fusion (MITLIF) to determine the incidence of pedicle screw misplacement and its relevant risk factors. Screw placements were classified based on postoperative computed tomographic findings as "correct", "cortical encroachment" or as "frank penetration". Age, gender, body mass index, bone mineral density, diagnosis, operation time, estimated blood loss (EBL), level of fusion, surgeon's position, spinal alignment, quality/quantity of multifidus muscle, and depth to screw entry point were considered to be demographic and anatomical variables capable of affecting pedicle screw placement. Pedicle dimensions, facet joint arthritis, screw location (ipsilateral or contralateral), screw length, screw diameter, and screw trajectory angle were regarded as screw-related variables. Logistic regression analysis was conducted to examine relations between these variables and the correctness of screw placement. The incidence of cortical encroachment was 12.5% (61 screws), and frank penetration was found for 54 (11.1%) screws. Two patients (0.4%) with medial penetration underwent revision for unbearable radicular pain and foot drop, respectively. The odds ratios of significant risk factors for pedicle screw misplacement were 3.373 (95% CI 1.095-10.391) for obesity, 1.141 (95% CI 1.024-1.271) for pedicle convergent angle, 1.013 (95% CI 1.006-1.065) for EBL >400 cc, and 1.003 (95% CI 1.000-1.006) for cross-sectional area of multifidus muscle. Although percutaneous insertion of pedicle screws was performed safely during MITLIF, several risk factors should be considered to improve placement accuracy.

Clinical Results and Complications of Endoscopic Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Meta-Analysis.

BACKGROUND: Although endoscopic transforaminal lumbar interbody fusion (TLIF) may combine the advantages of minimally invasive fusion and endoscopic spine surgery, little evidence exists on endoscopic TLIF. This meta-analysis investigated the clinical results of endoscopic TLIF. METHODS: We performed a systematic search of Web-based electronic databases to identify articles on endoscopic lumbar interbody fusion. Only studies of water-based endoscopic TLIF with pedicle screw fixation were included. We analyzed preoperative and postoperative scores for the Oswestry Disability Index (ODI) and visual analog scales (VASs) for back and leg pain to evaluate clinical efficacy. The minimal clinically important difference (MCID) of VAS and ODI was analyzed. We calculated differences in means and 95% confidence intervals and investigated indications for endoscopic TLIF, surgical approaches for endoscopic TLIF, the endoscopic systems that were used, and procedure-related complications. RESULTS: Thirteen articles were included in this meta-analysis. Uniportal and biportal endoscopic systems were used. Six articles used the posterolateral approach and 7 used the trans-Kambin approach. Preoperative ODI and VAS scores for leg and back pain significantly improved after endoscopic TLIF with percutaneous pedicle screw fixation (P = 0.00). The ODI significantly improved by twice as much as the MCID. The mean change in the VAS for back and leg pain showed significant improvements over the MCID. The perioperative complications were usually minor. CONCLUSIONS: The early clinical results of endoscopic TLIF with percutaneous pedicle screw fixation are favorable. However, long-term outcomes should be investigated and randomized controlled trials should be conducted.

The clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody single level fusion.

STUDY DESIGN: This is a retrospective study that was done according to clinical and radiological evaluation. PURPOSE: We analyzed the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody single level fusion. OVERVIEW OF LITERATURE: Minimally invasive transforaminal lumbar interbody fusion is effective surgical method for treating degenerative lumbar disease. METHODS: The study was conducted on 56 patients who were available for longer than 2 years (range, 24 to 45 months) follow-up after undergoing minimally invasive transforminal lumbar interbody single level fusion. Clinical evaluation was performed by the analysis of the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) and the Kirkaldy-Willis score. For the radiological evaluation, the disc space height, the segmental lumbar lordotic angle and the whole lumbar lordotic angle were analyzed. At the final follow-up after operation, the fusion rate was analyzed according to Bridwell's anterior fusion grade. RESULTS: For the evaluation of clinical outcomes, the VAS score was reduced from an average of 6.7 prior to surgery to an average of 1.8 at the final follow-up. The ODI was decreased from an average of 36.5 prior to surgery to an average of 12.8 at the final follow-up. In regard to the clinical outcomes evaluated by the Kirkaldy-Willis score, better than good results were obtained in 52 cases (92.9%). For the radiological evaluation, the disc space height (p = 0.002), and the whole lumbar lordotic angle (p = 0.001) were increased at the final follow-up. At the final follow-up, regarding the interbody fusion, radiological union was obtained in 54 cases (95.4%). CONCLUSIONS: We think that if surgeons become familiar with the surgical techniques, this is a useful method for minimally invasive spinal surgery.