Study design: Prospective matched-control comparison study.

Objective: To prospectively compare deformity correction and measures of perioperative morbidity between minimally invasive posterior spinal fusion and conventional open posterior procedures in age- and curve classificationmatched individuals.

Summary of background data: Minimally invasive surgery (MIS) has evolved in an effort to decrease the rate of approach-related morbidity associated with conventional open procedures for spinal disorders. Its widespread use in spinal trauma and degenerative disorders has yielded similar clinical results to open techniques with the added benefit of optimizing peri-operative morbidity. No report has been made comparing the clinical results of MIS to conventional open procedures in the setting of adolescent idiopathic scoliosis (AIS).

Methods: Patients enrolled in a multi-center, longitudinal, prospective AIS study were included in this analysis. Pre-op, peri-op and first erect post-op data was evaluated. 16 MIS patients were matched for age, sex, Lenke classification, and curve size with 16 conventional open posterior procedures. All cases were also matched to a single surgeon to reduce potential surgeon-induced variability. Statistical analysis was done using SPSS v.18.

Results: Age, gender, Lenke classification and curve magnitude were not statistically different between individuals treated with MIS or open surgery (Table 1). Post-op major Cobb was 20 degrees (curve correction 63%) in those treated with MIS and 18 degrees (curve correction 68%) in those treated with open surgery. Both estimated blood loss and length of stay (LOS) were significantly less in the MIS group (277 mL, 4.63 days) compared to the open group (388 mL, 6.19 days); however OR time was significantly longer in the MIS group (444 min) compared to the open group (350 min).

Conclusions: MIS for AIS has similar results to standard open posterior techniques, specifically for curve correction. Although increase in operative time was noted in the MIS group, advantages of MIS over standard open procedures seem to include decreased LOS and blood loss. Further follow-up will be critical to evaluating the longerterm outcomes of the MIS approach to AIS treatment.

Objectives: The purpose of the current case presentation was to indicate the usefulness of long thoracic and lumbar (TL) spinal stabilization by percutaneous minimally invasive instrumentation.

Materials and Methods: From August 2012 to May 2013, we performed long TL spinal stabilization with VIPER 2 system (Depuy Spine, Inc., MA, US) by using a minimally invasive surgery (MIS) posterior approach in 4 patients. The first case was a 54 year old male who suffered from burst fracture of T12 (Frankel A) with brain contusion by a fall. The second case was a 68 year old male who developed incomplete paraplegia by metastatic renal cell carcinoma of T11 (Frankel C). The third case was a 79 year old male who affected Chance fracture of T12 (Frankel E) with an ankylosing spinal hyperostosis. And the fourth case was a 75 year old male who sustained pathological fracture of T8 (Frankel A) due to metastasis of prostatic carcinoma accompanied by an ankylosing spinal hyperostosis. The assessment included the clinical outcome of the patients and implant imaging evaluation.

Results: Physical function was improved in all cases with quick pain relief. Mean operative time was 204 minutes. Mean estimated blood loss was 62.5 ml. In radiographic evaluation, spinal alignment was successfully maintained. One pedicle screw in case 3 cut out laterally in a pedicle-rib unit, but other pedicle screws in all cases were correctly inserted. No implant related complication was observed. And there were no conversions to open surgery.

Discussion: In comparison with conventional open surgery, intraoperative blood loss, operative time, and postoperative pain were remarkably decreased in a MIS technique. Long TL spinal stabilization with a MIS technique is useful method for the patients who are desirable to avoid major surgical procedure.

Minimally invasive approaches are becoming increasingly widespread due to numerous potential advantages (smaller scars, diminished local pain, reduced blood loss, reduced postoperative wound pain, shorter hospital stays) in spinal surgery. Nowadays, minimally invasive stabilization is more frequently used to treat some thoracolumbar fractures. The aim of this study is to explore the feasibility and effect of minimally invasive stabilization for the treatment of unstable thoracolumbar fractures without neurological impairment. From October 2011 to February 2012, 20 patients with thoracolumbar fracture who were treated with minimally invasive stabilization were included in this study. Charts and operative notes were analyzed for epidemiological data, injured segments, operative time, bleeding volume, mobilization interval, complications and lengths of stay. All patients were successfully managed with minimally invasive stabilization. There were 14 males and 6 females with a mean age of 33.75 years ranging from 18 to 59 years. The L1 vertebra was the most injured vertebral level (35%), followed by T12 and L2. Mechanisms of injury included falling from a height (12 patients) and traffic accidents (8 patients). The average operative time was 72 minutes (range 60 to 122 min). The average intraoperative blood loss was 80 ml (range 50 to 270 ml). Minimally invasive instrumentation of the spine reduces intraoperative blood loss, soft tissue trauma, operative time, infection rates and hospital stay. Future developments in minimally invasive technology will lead to improved results with increased indications and applications.

Object: Minimally invasive spine (MIS) procedures are increasingly being recognized as equivalent to open procedures with regard to clinical and radiographic outcomes. These techniques are also believed to result in less pain and disability in the immediate postoperative period. There are, however, little data to assess whether these procedures in combination with minimally invasive transforaminal interbody fusion (MI-TLIF) and percutaneous pedicle screw insertion are effective in complex cases of stenotic degenerative spondylolisthesis with severe facet joint osteoarthritis (FJO).

Methods: This study retrospectively reviewed all patients who underwent lumbar instrumentation, fusion and decompression for degenerative spondylolisthesis with severe stenosis and facet joint osteoarthritis (FJO) between June 2010 and June 2011. Blood loss, operative time and intraoperative complications were assessed in all surgically treated patients who were treated with MIS decompression, MI-TLIF and percutaneous transpedicular instrumentation. Clinical outcome was measured using the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for back pain, leg pain, and activity level. Satisfaction was assessed with VAS for satisfaction. Radiological follow-up includes x-ray films, computed tomography and in some cases magnetic tomography scan.

Results: Twenty four cases with severe stenotic changes accompanied by severe FJO were treated with minimally invasive procedure. The minimum follow-up was 6 months with a mean of 8 months. The mean preoperative ODI score was 46.8, decreasing to a mean of 23 postoperatively. The mean VAS leg and back pain scores were 67.5 improving to means of 25.8. Twenty one out of 24 cases experienced a clinical benefit according to VAS for satisfaction and ODI. Complications included wound healing disturbance (4%), CSF fistula (4%) and contralateral radiculopathy due to articular bone spurs (8%). The accuracy of pedicle screws was high and only one revision surgery was performed.

Conclusion: MIS for severe stenotic spondylolisthesis leads to adequate and safe decompression of lumbar stenosis and results in a highly significant reduction of symptoms and disability. MIS-TLIF and percutaneous pedicle screw insertion constitute a promising treatment alternative for patients with severe stenosis and facet joint osteoarthritis.

Objective: In minimally invasive techniques for transforaminal lumbar interbody fusion (MIS TLIF) access to the disc and by consequence, the extension of the discectomy can be reduced. Insufficient disc removal and endplate violation can lead to non-unions, subsidence and pseudoarthroses. In this study, we compare the quality of disc preparation, volume of bone graft and clinical results in a group of patients who underwent MIS TLIF with discectomy and endplate preparation aided by an automated discectomy device, the enSpireTM Flex MIS Surgical Discectomy System (study group) to a control group with classical, manual instrumentation for disc preparation.

Materials and methods: Twenty-seven consecutive patients were enrolled in the study group and 33 patients in the control group. All patients received similar mixture of autologous bone and cadaver allograft. Disc volume and the quantity of graft placed in the disc space was measured on the discharge CT scan and compared in a blinded, independent radiology review. Clinical outcomes assessed using the Visual Analog Scale (VAS) for leg and low back pain and the Oswestry Disability Index (ODI) were compared at 12 months postoperative.

Results: The mean volume of bone graft placed and the ratio bone graft/nucleus was higher in the study group (6.21 cm3 vs. 4.39 cm3 ; p<0001 and 76.8% vs. 57.8%; p<0.0001). The mean Patient Satisfaction Index (PSI) of the EnSpire group was statistically higher than the control group (4.6 ± 0.6 vs. 3.9 ± 0.7).

Conclusion: In the challenging MIS TLIF approach, we demonstrate that by using the enSpire™ Flex MIS Surgical Discectomy System, we can optimize the extension and quality of the discectomy, increase the volume of bone graft, and achieve better clinical outcomes.

Study design: Retrospective review of multiple cases.

Objectives: To understand the effectiveness of Percutaneous Endoscopic Discectomy (PED) for athletes. Summary of background data: PED was first performed in 2002 and showed good clinical outcome for normal subjects. However, there are few reports for athletes.

Methods: Ten male athletes with herniated nucleus pulposus underwent PED surgery under local anesthesia. Operation time, blood loss, and surgery-related complications were recorded. Changes in Visual Analog Scale (VAS) scores for low back pain and leg pain before and after surgery were reviewed. Time to return to play (RTP), RTP rate, and recurrence were also evaluated.

Results: Herniated fragments were successfully removed endoscopically. Mean operation time was 53.5 min, blood loss during operation was negligible, and no surgery-related complications such as dural tear, nerve root injury, hematoma, or surgical site infection were observed. Subjects returned to their sport 6 to 8 weeks after surgery. The mean VAS score (out of 10) for low back and leg pain was 0.5 and 0, respectively at the final follow-up, compared with 6.5 and 4.5 before surgery. Of the patients, 9 (90%) had complete RTP, and one (10%) showed recurrence.

Conclusions: The minimal invasiveness and good clinical outcome of PED favor it as a gold standard for disc surgery in athletes.

Study background: The application of MIS techniques to address complications of previous midline surgery has not been fully explored.

Methods: Three patients with previous midline lumbar surgery underwent revision surgery with minimally invasive approaches for management of either: infection, recurrent radiculopathyor symptomatic heterotopic bone formation.

Results: Patient 1 was found to have a persistent discitis 10 months after a lumbar fusion that was complicated by a pseudoarthrosis and infection requiring a second surgery for additional stabilization and third surgery for an incision and drainage. To avoid reopening the incision for a fourth time, a minimally invasive retractor was used to access the disc space and remove the interbody spacer. Patient 2 experienced a recurrent radiculopathy three months after an L5-S1 transforaminal lumbar interbody fusion. CT scan demonstrated heterotopic bone formation into the S1 neural foramen. A minimally invasive retractor was used through a paramedian incision to explant the pedicle screw rod construct on the symptomatic side, remove the heterotopic bone formation and decompress the neural foramen. Patient 3 experienced onset of an S1 radiculopathy 11 years after an L4 to S1 fusion. A fixed tubular minimally invasive retractor was used to access the S1 neural foramen and decompress the symptomatic root.

Conclusions: Minimally invasive spinal surgical techniques have the capacity to adequately address focal complications that have occurred with midline surgery. These techniques preclude the need to reopen a previous incision, which is especially valuable in those patients with delayed healing capacity, extensive previous surgery or previous infection.

Design: Retrospective linear radiological analysis study. Objective: To investigate the effects of AxiaLIF® on anterior disc height (ADH), posterior disc height (PDH), foraminal height (FH) and foraminal width (FW) and demonstrate that AxiaLIF® is an effective minimally-invasive surgery technique for indirect decompression and restoration of disc height. Background: Degenerative changes of the lumbar motion segment often lead to stenosis of the spinal canal or neuroforamen. AxiaLIF® is intended to indirectly increase and stabilize foraminal dimensions by restoring disc height in patients with degenerative disc disease, thereby relieving the axial and radicular pain. Method: Retrospective study of patients who underwent a 360Ë� lumbar interbody fusion at L4-5 and L5-S1 with AxiaLIF® between November 2008 and May 2010. Digital radiographs were analyzed on Kodak® computer software. ADH, PDH, FH, and FW, were measured. The anterior vertebral height of L5 vertebra was used to calibrate distance and eliminate potential magnification error for each radiograph. Results: Our study exhibited a mean increase in PDH and ADH at L4-5 and L5-S1 with 2-level AxiaLIF®. Similarly, a mean increase was observed in FH at L5-S1 and FW at L4-5 and L5-S1 with 2-level AxiaLIF®. All changes were statistically significant. The change in FW and FH were even more pronounced with 1-level AxiaLIF®, with a comparable change in posterior and anterior disc height (DH). Conclusion: AxiaLIF® acts to reduce instability by decreasing motion and fusing segments, thus reducing the dynamic compression of nerve roots and cauda equina. We conclude that AxiaLIF® is comparable to anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) in terms of indirect decompression and increased DH, with the added benefit of preserving the annulus, anterior longitudinal ligament, and posterior longitudinal ligament. Further observations are required to accurately assess whether AxiaLIF® maintains fusion and preserves disc and foraminal area long term.