Tranexamic acid reduces perioperative blood loss of posterior lumbar surgery for stenosis or spondylolisthesis: A randomized trial

BACKGROUND

A prospective, randomized, double-blind, placebo-controlled study was performed. The routine usage of TA in spinal surgery is controversial. Only a few studies have focused on patients undergoing posterior lumbar surgery for stenosis or spondylolisthesis, although a large clinical cohort exists in the population. This study aimed to evaluate the effect and safety of TA in reducing perioperative blood loss in posterior lumbar surgery for stenosis or spondylolisthesis.

METHODS

100 eligible patients out of 126 were randomized to receive either a bolus dose of 30 mg/kg TA i.v, a maintenance dosage of 2 mg/kg/h TA, or an equivalent volume of normal saline. The pedicle screw system was used for fixing in all the patients, followed by decompression and posterior lumbar interbody fusion. The primary outcomes were intraoperative estimated blood loss and total blood loss. The secondary outcomes were receiving packed red blood cells and postoperative hemoglobin and hematocrit levels.

RESULTS

In total, 4 patients were excluded from the analyses, 50 patients were in the TA group, and 46 in the placebo group. The demographic and baseline data between the groups were not statistically different. The intraoperative estimated blood loss and the total blood loss were 33% and 41% lower in the TA group than the placebo group, respectively. The blood transfusion rate did not vary significantly (P = 0.191). Except a patient with a dural tear in the placebo group, no other complications were observed.

CONCLUSION

TA significantly reduced the perioperative blood loss in patients undergoing posterior lumbar surgery for stenosis or spondylolisthesis.

Development of an Enhanced Recovery After Surgery (ERAS) approach for lumbar spinal fusion

OBJECTIVE Over the past decade, Enhancing Recovery After Surgery (ERAS) programs have been implemented throughout the world across multiple surgical disciplines. However, to date no spinal surgery equivalent has been described. In this report the authors review the development and implementation of a "fast track" surgical approach for lumbar fusion. METHODS The first 42 consecutive cases in which patients were treated with the new surgical procedure were reviewed. A combination of endoscopic decompression, expandable cage deployment, and percutaneous screw placement were performed with liposomal bupivacaine anesthesia to allow the surgery to be performed without general endotracheal anesthesia. RESULTS In all cases the surgical procedure was performed successfully without conversion to an open operation. The patients' mean age (± SD) was 66.1 ± 11.7 years, the male/female ratio was 20:22, and a total of 47 levels were treated. The mean operative time was 94.6 ± 22.4 minutes, the mean intraoperative blood loss was 66 ± 30 ml, and the mean hospital length of stay was 1.29 ± 0.9 nights. Early follow-up showed a significant improvement in the mean Oswestry Disability Index score (from 40 ± 13 to 17 ± 11, p = 0.0001). Return to the operating room was required in 2 cases due to infection and in 1 case due to cage displacement. An iterative quality improvement program demonstrated areas of improvement, including steps to minimize infection, improve postoperative analgesia, and reduce cage osteolysis. CONCLUSIONS ERAS programs for improving spinal fusion surgery are possible and necessary. This report demonstrates a first foray to apply these principles through 1) a patient-focused approach, 2) reducing the stress of the operation, and 3) an iterative improvement process.

Endoscopic minimally invasive transforaminal interbody fusion without general anesthesia: initial clinical experience with 1-year follow-up

OBJECTIVE One of the principal goals of minimally invasive surgery has been to speed postoperative recovery. In this case series, the authors used an endoscopic technique for interbody fusion combined with percutaneous screw fixation to obviate the need for general anesthesia. METHODS The first 10 consecutive patients treated with a minimum of 1 year's follow-up were included in this series. The patients were all treated using endoscopic access through Kambin's triangle to allow for neural decompression, discectomy, endplate preparation, and interbody fusion. This was followed by percutaneous pedicle screw and connecting rod placement using liposomal bupivacaine for long-acting analgesia. No narcotics or regional anesthetics were used during surgery. RESULTS All patients underwent the procedure successfully without conversion to open surgery. The patients' average age was 62.2 ± 9.0 years (range 52-78 years). All patients had severe disc height collapse, and 60% had a Grade I spondylolisthesis. The mean operative time was 113.5 ± 6.3 minutes (range 105-120 minutes), and blood loss was 65 ± 38 ml (range 30-190 ml). The mean length of hospital stay was 1.4 ± 1.3 nights. There were no intraoperative or postoperative complications. Comparison of preoperative and final clinical metrics demonstrated that the Oswestry Disability Index improved from 42 ± 11.8 to 13.3 ± 15.1; the 36-Item Short Form Health Survey (SF-36) Physical Component Summary improved from 47.6 ± 3.8 to 49.7 ± 5.4; the SF-36 Mental Component Summary decreased from 47 ± 3.9 to 46.7 ± 3.4; and the EQ-5D improved from 10.7 ± 9.5 to 14.2 ± 1.6. There were no cases of nonunion identified radiographically on follow-up imaging. CONCLUSIONS Endoscopic fusion under conscious sedation may represent a feasible alternative to traditional lumbar spine fusion in select patients. Larger clinical series are necessary to validate that clinical improvements are sustained and that arthrodesis rates are successful when compared with open surgery. This initial experience demonstrates the possible utility of this procedure.

Minimally Invasive Direct Thoracic Interbody Fusion (MIS-DTIF): Technical Notes of a Single Surgeon Study

Background

Minimally invasive direct thoracic interbody fusion (MIS-DTIF) is a new single surgeon procedure for fusion of the thoracic vertebrae below the scapula (T6/7) to the thoracolumbar junction. In this proof of concept study, we describe the surgical technique for MIS-DTIF and report our experience and the perioperative outcomes of the first four patients who underwent this procedure.

Study design/setting

In this study we attempt to establish the safety and efficacy of MIS-DTIF. We have performed MIS-DTIF on six spinal levels in four patients with degenerative disk disease or disk herniation. We recorded surgery time, blood loss, fluoroscopy time, complications, and patient-reported pain.

Methods

Throughout the MIS-DTIF procedure, the surgeon is aided by biplanar fluoroscopic imaging and electrophysiological monitoring. The surgeon approaches the spine with a series of gentle tissue dilations and inserts a working tube that establishes a direct connection from the outside of the skin to the disk space. Through this working tube, the surgeon performs a discectomy and inserts an interbody graft or cage. The procedure is completed with minimally invasive (MI) posterior pedicle screw fixation.

Results

For the single level patients the mean blood loss was 90 ml, surgery time 43 minutes, fluoroscopy time 293 seconds, and hospital stay two days. For the two-level surgeries, the mean blood loss was 27 ml, surgery time 61 minutes, fluoroscopy time 321 seconds, and hospital stay three days. We did not encounter any clinically significant complications. Thirty days post-surgery, the patients reported a statistically significant reduction of 5.3 points on a 10-point sliding pain scale.

Conclusions

MIS-DTIF with pedicle screw fixation is a safe and clinically effective procedure for fusions of the thoracic spine. The procedure is technically straightforward and overcomes many of the limitations of the current minimally invasive (MI) approaches to the thoracic spine. MIS-DTIF has the potential to improve patient outcomes and reduce costs relative to the current standard of care. We are currently expanding this study to a larger cohort and recording long term outcomes and costs.

Focal Correction of Severe Fixed Kyphosis with Single Level Posterior Ponte Osteotomy and Interbody Fusion

Objective: To report the successful correction of a severe, fixed kyphotic deformity utilizing a combination posterior lumbar interbody fusion (PLIF) and Ponte osteotomy at the site of acute kyphosis.

Summary of Background Data: There have been no reports on the experience and surgical strategy of combined one-level focal PLIF and Ponte osteotomy for fixed severe kyphotic deformity. Typically, these corrections would need a pedicle subtraction osteotomy or a vertebrectomy.

Methods: A 24-year-old man presented with progressive back pain and a fixed severe thoracolumbar kyphosis centered at the L2-L3 disc space seven years after removal of instrumentation for intractable infection following correction of Scheuermann's Kyphosis. The patient also demonstrated pseudoarthrosis of the posterior thoracolumbar fusion bed. The original operative plan was to perform a vertebral column resection (VCR) of L2 to correct his severe kyphosis.  During preparation for the VCR, the patient’s deformity corrected completely after insertion of blunt distraction paddles for the interbody fusion after the Ponte osteotomy at L2-L3. A VCR was avoided, and the construct was able to be completed with simple rod insertion and posterolateral fusion.

Results: The described technique achieved 69 degrees of correction at the L2-L3 disc space without any remodeling of the surrounding vertebrae. The C7 plumb line was normalized, and the patient was able to stand upright with horizontal gaze and without pre-existing discomfort. At the six-month follow-up, the patient reported a significant improvement in pain and was able to resume normal activities.

Treatment of Recurrent Disc Herniation: A Systematic Review

Intervertebral disc herniation is one of the most common causes of back and extremity pain. The most commonly used surgical treatment is lumbar discectomy. About 0.5-25% go on to develop recurrent disc herniation (rDH) after a successful first discectomy. Currently, there aren't any guidelines to assist surgeons in determining which approach is most appropriate to treat rDH. A recent survey showed significant heterogeneity among surgeons regarding treatment options for rDH. It remains unclear which methods lead to better outcomes, as there are no comparative studies with a sufficient level of evidence. In this study, we aimed to perform a systematic review to compare treatment options for rDH and determine if one intervention provides better outcomes than the other; more specifically, whether outcome differences exist between discectomy alone and discectomy with fusion. We applied the PICOS (participants, intervention, comparison, outcome, study design) format to develop this systematic review through PubMed. Twenty-seven papers from 1978-2014 met our inclusion criteria and were included in the analysis. Nine papers reported outcomes after discectomy and seven of them showed good or excellent outcomes (70.60%-89%). Ten papers reported on minimally invasive discectomy. The percent change in visual analog scale (VAS) ranged from -50.77% to -86.57%, indicating an overall pain reduction. Four studies out of the ten reported good or excellent outcomes (81% to 90.2%). Three studies looked at posterolateral fusion. Three studies analyzed posterior lumbar interbody fusion. For one study, we found the VAS percentage change to be -46.02%. All reported good to excellent outcomes. Six studies evaluated the transforaminal lumbar interbody fusion. All reported improvement in pain. Four used VAS, and we found the percent change to be -54% to -86.5%. The other two used the Japanese Orthopedic Association (JOA) score, and we found the percent change to be 68.3% to 93.3%. We did not find enough evidence to support any significant difference in outcomes between discectomy alone and discectomy with fusion. The limitation of our study includes the lack of standardized outcomes reporting in the literature. However, reviewing the selected articles shows that fusion may have a greater improvement in pain compared to reoperation without fusion. Nonetheless, our study shows that further and more in-depth investigation is needed on the of treatment of rDH.

Novel spinal instrumentation to enhance osteogenesis and fusion: a preliminary study

OBJECTIVE Instrumented spinal fusion continues to exhibit high failure rates in patients undergoing multilevel lumbar fusion or pseudarthrosis revision; with Grade II or higher spondylolisthesis; or in those possessing risk factors such as obesity, tobacco use, or metabolic disorders. Direct current (DC) electrical stimulation of bone growth represents a unique surgical adjunct in vertebral fusion procedures, yet existing spinal fusion stimulators are not optimized to enhance interbody fusion. To develop an advanced method of applying DC electrical stimulation to promote interbody fusion, a novel osteogenic spinal system capable of routing DC through rigid instrumentation and into the vertebral bodies was fabricated. A pilot study was designed to assess the feasibility of osteogenic instrumentation and compare the ability of osteogenic instrumentation to promote successful interbody fusion in vivo to standard spinal instrumentation with autograft. METHODS Instrumented, single-level, posterior lumbar interbody fusion (PLIF) with autologous graft was performed at L4-5 in adult Toggenburg/Alpine goats, using both osteogenic spinal instrumentation (plus electrical stimulation) and standard spinal instrumentation (no electrical stimulation). At terminal time points (3 months, 6 months), animals were killed and lumbar spines were explanted for radiographic analysis using a SOMATOM Dual Source Definition CT Scanner and high-resolution Microcat II CT Scanner. Trabecular continuity, radiodensity within the fusion mass, and regional bone formation were examined to determine successful spinal fusion. RESULTS Quantitative analysis of average bone density in pedicle screw beds confirmed that electroactive pedicle screws used in the osteogenic spinal system focally enhanced bone density in instrumented vertebral bodies. Qualitative and quantitative analysis of high-resolution CT scans of explanted lumbar spines further demonstrated that the osteogenic spinal system induced solid bony fusion across the L4-5 disc space as early as 6 weeks postoperatively. In comparison, inactive spinal instrumentation with autograft was unable to promote successful interbody fusion by 6 months postoperatively. CONCLUSIONS Results of this study demonstrate that novel osteogenic spinal instrumentation supports interbody fusion through the focal delivery of DC electrical stimulation. With further technical development and scientific/clinical validation, osteogenic spinal instrumentation may offer a unique alternative to biological scaffolds and pharmaceutical adjuncts used in spinal fusion procedures.

Posterior convex release and interbody fusion for thoracic scoliosis: technical note

Anterior release and fusion is sometimes required in pediatric patients with thoracic scoliosis. Typically, a formal anterior approach is performed through open thoracotomy or video-assisted thoracoscopic surgery. The authors recently developed a technique for anterior release and fusion in thoracic scoliosis referred to as "posterior convex release and interbody fusion" (PCRIF). This technique is performed via the posterior-only approach typically used for posterior instrumentation and fusion and thus avoids a formal anterior approach. In this article the authors describe the technique and its use in 9 patients-to prevent a crankshaft phenomenon in 3 patients and to optimize the correction in 6 patients with a severe thoracic curve showing poor reducibility. After Ponte osteotomies at the levels requiring anterior release and fusion, intervertebral discs are approached from the convex side of the scoliosis. The annulus on the convex side of the scoliosis is incised from the lateral border of the pedicle to the lateral annulus while visualizing and protecting the pleura and spinal cord. The annulus in contact with the pleura and the anterior longitudinal ligament are removed before completing the discectomies and preparing the endplates. The PCRIF was performed at 3 levels in 4 patients and at 4 levels in 5 patients. Mean correction of the main thoracic curve, blood loss, and length of stay were 74.9%, 1290 ml, and 7.6 days, respectively. No neurological deficit, implant failure, or pseudarthrosis was observed at the last follow-up. Two patients had pleural effusion postoperatively, with 1 of them requiring placement of a chest tube. One patient had pulmonary edema secondary to fluid overload, while another patient underwent reoperation for a deep wound infection 3 weeks after the initial surgery. The technique is primarily indicated in skeletally immature patients with open triradiate cartilage and/or severe scoliosis. It can be particularly useful if there is significant vertebral rotation because access to the disc and anterior longitudinal ligament from the convex side will become safer. The PCRIF is an alternative to the formal anterior approach and does not require repositioning between the anterior and posterior stages, which prolongs the surgery and can be associated with an increased complication rate. The procedure can be done in the presence of preexisting pulmonary morbidity such as pleural adhesions and decreased pulmonary function because it does not require mobilization of the lung or single-lung ventilation. However, PCRIF can still be associated with pulmonary complications such as a pleural effusion, and care should be taken to avoid iatrogenic injury to the pleura. Placement of a deep wound drain at the level of the PCRIF is strongly recommended if postoperative bleeding is anticipated, to decrease the risk of pleural effusion.

Biomechanical evaluation of CIBOR spine interbody fusion device

BACKGROUND

The CIBOR PEEK spinal interbody fusion device is an anterior lumbar interbody fusion construct with a hollow center designed to accommodate an osteoinductive carbon foam insert to promote bony ingrowth to induce fusion where rigid stabilization is needed.

METHODS

Three different sizes of the device were investigated. Part-I: implants were tested under axial compression and rotation using polyurethane foam blocks. Part-II: simulated 2-legged stance using cadaveric specimen using the L5-S1 lumbar spine segment. Part-III: a survey feedback form was used to investigate two orthopedic surgeons concern regarding the implant.

RESULTS

In Part-I, the subsidence hysteresis under axial compression loading was found to be statistical significant difference between these three implant sizes. It was noted that the implants had migration as rotation applied, and the amount of subsidence was a factor of the axial compression loads applied. In Part-II, a minor subsidence and carbon foam debris were observed when compared to each implant size. Poor contact surface of the implant with the end plates of the L5 or S1 vertebrae from the anterior view under maximum loads was observed; however, the implant seemed to be stable. Each surgeon has their own subjective opinion about the CIBOR implant.

DISCUSSION

Two out of the three different sizes of the device (medium and large sizes) provided appropriate rigid stabilization at the physiological loads. Neither orthopedic surgeon was 100% satisfied with overall performance of the implant, but felt potential improvement could be made.

CLINICAL RELEVANCE

This study indicates an option for operative treatment of spine interbody fusion, as the CIBOR spine interbody fusion device has a hollow center. This hollow center is designed to accommodate a carbon foam insert to promote bony ingrowth. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1157-1168, 2017.

Mini-open pedicle subtraction osteotomy as a treatment for severe adult spinal deformities: case series with initial clinical and radiographic outcomes

OBJECTIVE Pedicle subtraction osteotomy (PSO) is a powerful but high-risk surgical technique for destabilizing the spine for deformity correction in both the sagittal and coronal planes. Numerous reports have demonstrated the benefits of this technique for realigning the spine in a physiological posture; however, the open surgical technique is associated with a high complication rate. In this report the authors review data obtained in a series of patients who underwent PSO through a less invasive approach. METHODS Sixteen patients with severe coronal- and/or sagittal-plane deformities were treated in this series. Conservative measures had failed in all cases and patients had undergone a single-level PSO or extended PSO at L-2 or L-3. Fixation was accomplished using percutaneous instrumentation and interbody or facet joint fusions were used at the remaining levels. None of the procedures were aborted or converted to a traditional open procedure. Standard clinical and radiographic measures were used to assess patient outcomes. RESULTS Mean age was 68.8 years and mean follow-up duration was 17.7 months. An average of 7.6 levels were fused, and 50% of the patients had bilateral iliac screw fixation, with all constructs crossing both the thoracolumbar and lumbosacral junctions. Operative time averaged 356 ± 50 minutes and there was a mean blood loss of 843 ± 339 ml. The leg visual analog scale score improved from a mean of 5.7 ± 2.7 to one of 1.3 ± 1.6, and the back visual analog scale score improved from a mean of 8.6 ± 1.3 to one of 2.4 ± 2.1. The Oswestry Disability Index score improved from a mean of 50.1 ± 14.4 to 16.4 ± 12.7, representing a mean reduction of 36.0 ± 16.9 points. The SF-36 physical component summary score changed from a mean of 43.4 ± 2.6 to one of 47.0 ± 4.3, and the SF-36 mental component summary score changed from a mean of 46.7 ± 3.6 to 46.30 ± 3.0. Coronal alignment improved from a mean of 27.9 ± 43.6 mm to 16.0 ± 17.2 mm. The lumbar Cobb angle improved from a mean of 41.2° ± 18.4° to 15.4° ± 9.6°, and lumbar lordosis improved from 23.1° ± 15.9° to 48.6° ± 11.7°. Pelvic tilt improved from a mean of 33.7° ± 8.6° to 24.4° ± 6.5°, and the sagittal vertical axis improved from 102.4 ± 73.4 mm to 42.2 ± 39.9 mm. The final lumbar lordosis-pelvic incidence difference averaged 8.4° ± 12.1°. There were 4 patients who failed to achieve less than or equal to a 10° mismatch on this parameter. Ten of the 16 patients underwent delayed postoperative CT, and 8 of these had developed a solid arthrodesis at all levels treated. A total of 6 complications occurred in this series. There were no cases of symptomatic proximal junction kyphosis. CONCLUSIONS Advancements in minimally invasive technique have resulted in the ability to manage increasingly complex deformities with hybrid approaches. In this limited series, the authors describe the results of utilizing a tissue-sparing mini-open PSO to correct severe spinal deformities. This method was technically feasible in all cases with acceptable radiographic outcomes similar to open surgery. However, high complication rates associated with these deformity corrections remain problematic.

Oblique Lateral Lumbar Interbody Fusion (OLLIF): Technical Notes and Early Results of a Single Surgeon Comparative Study

BACKGROUND CONTEXT

 Lower back pain is one of the most prevalent and expensive health conditions in the Western world. The standard treatment, interbody fusion, is an invasive procedure that requires the stripping of muscles and soft tissue, leading to surgical morbidity. Current minimally invasive (MI) spinal fusions are technically demanding and suffer from technical limitations.

PURPOSE

Oblique lumbar lateral interbody fusion (OLLIF) is a new technique for fusion of the lumbar spine that overcomes these complications. Outcome measures include patient demographics, reported outcomes, and surgical outcomes.

STUDY DESIGN/SETTING

 Kambin's Triangle can easily be located as a silent window with an electrophysiological probe. Discectomy is performed through a single access portal with a 10 mm diameter. After a discectomy, the disc space is packed with beta-tricalcium phosphate soaked in autologous bone marrow, aspirated, and the cage is inserted. Finally, a minimally invasive posterior fixation is performed.

METHODS

OLLIF's major innovation is to approach the disc through Kambin's Triangle, aided by bilateral fluoroscopy.

RESULTS

 We present data from 69 consecutive OLLIF surgeries on 128 levels with a control group of 55 consecutive open transformational lumbar interbody fusions (TLIFs) on 125 levels. For a single level OLLIF, the mean surgery time is 69 minutes (min) and blood loss is 29 ml. Surgery time was approximately twice as fast as open TLIF (mean: 135 min) and blood loss is reduced by over 80% compared to TLIF (mean: 355 ml).

CONCLUSIONS

 OLLIF is a minimally invasive fusion that significantly reduces surgery times compared to open surgery. OLLIF overcomes the difficulties of traditional open fusions, making it a safe and technically less demanding surgery than open or minimally invasive TLIF.

Expandable Polyaryl-Ether-Ether-Ketone Spacers for Interbody Distraction in the Lumbar Spine

Study Design Retrospective case series. Objective StaXx XD (Spine Wave, Inc., Shelton, CT, United States) is an expandable polyaryl-ether-ether-ketone (PEEK) wafer implant utilized in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. Few studies have focused on expandable PEEK devices. The aim of the current study is to determine the radiographic and clinical outcome of expandable PEEK cages utilized for transforaminal lumbar interbody fusion in patients with lumbar degenerative diseases. Methods Forty-nine patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages and posterior instrumentation were included. The clinical outcome was evaluated using the visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiographic parameters including disk height, foraminal height, listhesis, local disk angle of the index level/levels, regional lumbar lordosis, and graft subsidence were measured preoperatively, postoperatively, and at latest follow-up. Results At an average follow-up of 19.3 months, the minimum clinically important difference for the ODI and VAS back, buttock, and leg were achieved in 64, 52, 58, and 52% of the patients, respectively. There was statistically significant improvement in VAS back (6.42 versus 3.11, p < 0.001), VAS buttock (4.66 versus 1.97, p = 0.002), VAS leg (4.55 versus 1.96, p < 0.001), and ODI (21.7 versus 12.1, p < 0.001) scores. There was a significant increase in the average disk height (6.49 versus 8.18 mm, p = 0.037) and foraminal height (15.6 versus 18.53 mm, p = 0.0001), and a significant reduction in the listhesis (5.13 versus 3.15 mm, p = 0.005). The subsidence of 0.66 mm (7.4%) observed at the latest follow-up was not significant (p = 0.35). Conclusions Midterm results indicate that expandable PEEK spacers can effectively and durably restore disk and foraminal height and improve the outcome without significant subsidence.

Mast Quadrant-assisted minimally invasive modified transforaminal lumbar interbody fusion: single incision versus double incision

BACKGROUND

The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion (TLIF) with a small single posterior median incision.

METHODS

During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision (single incision group). The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index (ODI) scores, Visual Analog Scale (VAS) scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared.

RESULTS

A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group (P < 0.01). The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups (P ≥ 0.05).

CONCLUSIONS

Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

Long-term clinical outcomes of selective segmental transforaminal lumbar interbody fusion combined with posterior spinal fusion for degenerative lumbar scoliosis

BACKGROUND

The purpose of the current study was to investigate the long-term clinical outcomes of this technique for degenerative scoliosis (DS).

METHODS

The records of 95 consecutive patients with DS who underwent selective segmental transforaminal interbody fusion combined with posterior-instrumented spinal fusion in our department from January 1999 to December 2007 were analysed retrospectively. Average follow-up was 7.8 years. Recorded clinical outcomes included Oswestry Disability Index (ODI), visual analogue scale (VAS) pain scores and overall patient satisfaction. Radiographic measurements included coronal Cobb angle, apical vertebra translation, Nash-Moe grade, lumbar lordosis (LL) and thoracolumbar kyphosis. Comparison of the clinical and radiographic parameters before surgery and at final follow-up was studied. Linear correlation analysis was applied to analyse the relationship between the clinical and radiological results.

RESULTS

Average ODI and VAS pain scores were significantly improved at final follow-up compared with baseline (P=0.038; P=0.005). Specifically, the average ODI score was 32.2±8.6 before surgery and 11.1±6.8 at final follow-up; the average VAS score was 8.9±2.0 before surgery and 2.0±1.2 at final follow-up; patient satisfaction was 88.2% (84/95) at final follow-up. In addition, Cobb angle, apical vertebra translation and Nash-Moe grade were all statistically significantly decreased compared with preoperative values (P=0.019; P=0.035; P=0.001). Although LL had significantly increased (P=0.022), thoracolumbar kyphosis did not exhibit a significant change (P=0.64). There was significant correlation between LL and decreased ODI scores (r=0.62, P=0.01). Eleven patients (11.6%) underwent reoperation during the study period.

CONCLUSION

Selective segmental transforaminal interbody fusion combined with posterior-instrumented spinal fusion appears to have reasonable long-term clinical and radiographic outcomes for the treatment of DS.

Alternative Surgical Strategy for AxiaLIF Pseudarthrosis: A Series of Three Case Reports

Study Design Retrospective case series.

Objective The objective of this study is to describe an alternative technique to attain interbody lumbar fusion in the event of pseudarthrosis after axial lumbar interbody fusion (AxiaLIF) and to assess its safety.

Methods Three patients who suffered from pseudarthrosis after AxiaLIF underwent revision surgery with a DEVEX cage (DePuy Synthes, Raynham, MA, United States) through an anterior approach. We report technical details as well as clinical and radiological results at 12 months follow-up.

Results Preoperative symptoms resolved in all cases. There were no perioperative complications. One patient had a deep venous thrombosis at postoperative day 9. A decrease in visual analog scale score for pain was observed, from 8.67 preoperatively to 2 postoperatively at final follow-up. Radiographic workup after 12 months showed no sign of implant failure or loosening, and fusion was obtained in all cases.

Conclusion Anterior fusion with a DEVEX cage in front of a TranS1 screw (TranS1 screw, Inc., Wilmington, North Carolina, United States) for AxiaLIF pseudarthrosis is safe and effective.

Porous biodegradable lumbar interbody fusion cage design and fabrication using integrated global-local topology optimization with laser sintering

Biodegradable cages have received increasing attention for their use in spinal procedures involving interbody fusion to resolve complications associated with the use of nondegradable cages, such as stress shielding and long-term foreign body reaction. However, the relatively weak initial material strength compared to permanent materials and subsequent reduction due to degradation may be problematic. To design a porous biodegradable interbody fusion cage for a preclinical large animal study that can withstand physiological loads while possessing sufficient interconnected porosity for bony bridging and fusion, we developed a multiscale topology optimization technique. Topology optimization at the macroscopic scale provides optimal structural layout that ensures mechanical strength, while optimally designed microstructures, which replace the macroscopic material layout, ensure maximum permeability. Optimally designed cages were fabricated using solid, freeform fabrication of poly(ε-caprolactone) mixed with hydroxyapatite. Compression tests revealed that the yield strength of optimized fusion cages was two times that of typical human lumbar spine loads. Computational analysis further confirmed the mechanical integrity within the human lumbar spine, although the pore structure locally underwent higher stress than yield stress. This optimization technique may be utilized to balance the complex requirements of load-bearing, stress shielding, and interconnected porosity when using biodegradable materials for fusion cages.

Clinical study of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability

The aim of this study was to observe the clinical effects of bilateral decompression via vertebral lamina fenestration for lumbar interbody fusion in the treatment of lower lumbar instability. The 48 patients comprised 27 males and 21 females, aged 47–72 years. Three cases had first and second degree lumbar spondylolisthesis and all received bilateral vertebral lamina fenestration for posterior lumbar interbody fusion (PLIF) using a threaded fusion cage (TFC), which maintains the three-column spinal stability. Attention was given to ensure the correct pre-operative fenestration, complete decompression and the prevention of adhesions. After an average follow-up of 26.4 months, the one year post-operative X-ray radiographs suggested that the successful fusion rate was 88.1%, and this was 100% in the two-year post-operative radiographs. Moreover, the functional recovery rate was 97.9%. Bilateral vertebral lamina fenestration for lumbar interbody fusion is an ideal surgical method for the treatment of lower lumbar instability. The surgical method retains the spinal posterior column and middle column and results in full decompression and reliable fusion by a limited yet effective surgical approach.

Assessment of BioPlex interbody fusion device in a sheep lumbar fusion model

OBJECTIVE

The purpose of this study was to evaluate the bioPlex bioresorbable interbody device in a sheep lumbar fusion model and compare it to the concorde, a standard carbon fiber interbody cage.

BACKGROUND

Lumbar interbody fusion devices are made from a variety of materials, including titanium alloys, carbon-fiber, and PEEK. The BioPlex Continuous Phase Composite (CPC) is a unique bioresorbable material comprised of Pro Osteon 500R and 70:30 Poly (L/D, L-lactic acid). The BioPlex device is radiolucent, resorbable and due to its bulk nanoporosity of 8%, has a more consistent degradation profile as compared to a polymer alone.

METHODS

A total of twenty five male Suffolk sheep were used in this study; nineteen of which were implanted with a bioPlex or concorde device at the L3-L4 and L5-L6 levels using a modified transforaminal/lateral approach. A discectomy was performed and each implant (filled with autologous bone) was placed within the disc space. The sheep were sacrificed at 6, 12, 24 months postimplantation. Fusion was assessed via motion, radiographic and histological data.

RESULTS

The BioPlex and Concorde implanted levels had significantly less motion (p<0.05) than the normal controls in flexion/extension and lateral bending at 6, 12, and 24 months. No significant difference in motion was detected between the bioPlex and concorde implants. CT fusion scores correlated with the motion analysis in all the three cases.

CONCLUSION

In comparison to the concorde device, the bioPlex implant appears to have equivalent radiographic and biomechanical fusion success.

Significant relationship between local angle at fused segments and C2-7 angle: Average duration of longer than 20 years after anterior cervical discectomy and fusion

Background:

The authors have focused their attention to the radiological durability of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF) using autologous bone grafting.

Materials and Methods:

Among the patients who underwent ACDF with trans-unco-discal (TUD) approach between 1976 and 1997, 22 patients (16 males and 6 females) made return visits for a clinical evaluation. Patients with trauma or previously treated by anterior cervical fusion or by posterior decompression were excluded from the present study. Clinical evaluation included adjacent segment degeneration (ASD), osseous fusion, local angle at the fused segments and C2-7 angle of cervical spine.

Results:

The duration after ACDF ranged from 13 to 34 years with an average of 21.3 ± 7.0 years. A single level fusion was done on 8 patients, 2 levels on 11 patients, 3 levels on 2 patients, and 4 levels on 1 patient. Imaging studies indicated that 12 of the 22 patients (54.5%) were graded as having symptomatic ASD. Osseous bony fusion at ACDF was recognized in all cases. None of the patients demonstrated kyphotic malalignment of the cervical spine. Average degrees of local angle at the fused segments and the C2-7 angle were 7.06 and 17.6, respectively. Statistical analysis indicated a significant relationship between the local at the fused segments and C2-7 angles.

Conclusions:

Sagittal alignment of the cervical spine was durable long after ACDF when the local angle at the fused segments was well stabilized.

Anterior elongation as a minimally invasive alternative for sagittal imbalance-a case series

BACKGROUND

Degenerative and iatrogenic conditions may lead to flat back or even to kyphotic deformity, and sagittal imbalance can cause significant clinical impairment. Minor imbalance cases are usually treated with conservative care. Among currently popular surgical techniques for the correction of sagittal imbalance are posterior-based procedures, which are associated with access-related risks (mostly neurological) and postoperative morbidity risks.

PURPOSE

This study aims to report a minimally invasive lateral approach using hyperlordotic cages in the treatment of mild sagittal imbalance. Radiological correction, clinical improvement, and safety will be analyzed.

METHODS

Eight patients (mean age 71.8 years, SD 7.8; mean BMI 27.5, SD 2.3) with symptomatic sagittal imbalance were retrospectively reviewed. Eight cases were treated by anterior interbody fusion with lordotic cages. A minimally invasive lateral retroperitoneal approach was used in the surgical procedures, with or without percutaneous pedicle screw supplementation.

RESULTS

No major complications occurred and just one case needed revision for direct decompression. Clinical outcomes Visual Analog Scale score changed from 88 at preoperative visit to 51 at 1-week visit, and Oswestry Disability Index score decreased from 82 at preoperative visit to 44 at 6-week visit. The 6-month radiological assessment revealed improvement in spinopelvic parameters: Focal lordosis improved from 2.3° ± 7.7 to 27.1° ± 6.7. Sagittal vertical alignment improved from 11.7 ± 5.3 to 6.2 ± 4.0 cm. Preoperative sacral slope improved from 20.1° ± 5.8 to 29.4° ± 10.3 and preoperative pelvic tilt improved from 35.2° ± 5.2 to 23.8° ± 4.3. Short-term results indicate that the minimally invasive lateral approach can be applied to the treatment of mild sagittal imbalance, with special advantage in elderly patients or those in which posterior approaches are relatively contraindicated.

Multifidus muscle changes and clinical effects of one-level posterior lumbar interbody fusion: minimally invasive procedure versus conventional open approach

We set out to determine whether a minimally invasive approach for one-level instrumented posterior lumbar interbody fusion reduced undesirable changes in the multifidus muscle, compared to a conventional open approach. We also investigated associations between muscle injury during surgery (creatinine kinase levels), clinical outcome and changes in the multifidus at follow-up. We studied 59 patients treated by one team of surgeons at a single institution (minimally invasive approach in 28 and conventional open approach in 31, voluntarily chosen by patients). More than 1 year postoperatively, all the patients were followed up with the visual analogue scale (VAS) and Oswestry disability index (ODI), and 16 patients from each group were evaluated using MRI. This enabled the cross-sectional area (CSA) of lean multifidus muscle, and the T2 signal intensity ratio of multifidus to psoas muscle, to be compared at the operative and adjacent levels. The minimally invasive group had less postoperative back pain (P < 0.001) and lower postoperative ODI scores (P = 0.001). Multifidus atrophy was less in the minimally invasive group (P < 0.001), with mean reductions in CSA of 12.2% at the operative and 8.5% at the adjacent levels, compared to 36.8% and 29.3% in the conventional open group. The increase in the multifidus:psoas T2 signal intensity ratio was similarly less marked in the minimally invasive group where values increased by 10.6% at the operative and 8.3% at the adjacent levels, compared to 34.4 and 22.7% in the conventional open group (P < 0.001). These changes in multifidus CSA and T2 signal intensity ratio were significantly correlated with postoperative creatinine kinase levels, VAS scores and ODI scores (P < 0.01). The minimally invasive approach caused less change in multifidus, less postoperative back pain and functional disability than conventional open approach. Muscle damage during surgery was significantly correlated with long-term multifidus muscle atrophy and fatty infiltration. Furthermore these degenerative changes of multifidus were also significantly correlated with long-term clinical outcome.

Predictors of outcomes after posterior decompression and fusion in degenerative spondylolisthesis

No consensus has been reached regarding surgical management of degenerative spondylolisthesis. The optimal type of surgical procedure and surgical indications have not been precisely defined. In order to screen for predictors of outcome, we retrospectively studied patient outcomes after posterior decompression and fusion for isolated lumbar degenerative spondylolisthesis. Twenty-four consecutive patients (age range 50-78 years) underwent primary surgery for isolated lumbar degenerative spondylolisthesis. The surgical procedure consisted of posterior decompression and pedicle screw instrumented fusion using autogeneous bone graft, with or without interbody fusion. Clinical and radiologic status were assessed using the Beaujon functional score and plain AP and lateral radiographs. A multivariate analysis was used to correlate the functional score increase with surgical procedure modifications and preoperative clinical and radiologic features in order to determine which of them led to better results. Eighteen patients completed the evaluation. Six others were lost to follow-up after a minimum of 0.87 years. Combining all the results, the mean follow-up was 2.87 years. The Beaujon score was improved in the 24 patients (P<0.001), and fusion was successful in all cases. Additional interbody fusion and preoperative leg pain were significantly correlated with larger score increase (P=0.016 and P=0.003). Posterior decompression and fusion is successful in treating lumbar degenerative spondylolisthesis. From this study, circumferential fusion improves the outcomes and leg pain is a fair indication for surgery.

Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion

Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (score< or =30) on the subjective (quality of life questionnaire) score of 71.8% (28 patients) in the ALIF group and 74.3% (26 patients) in the PLIF group (P>0.05). On categorising Oswestry Index scores into "excellent", "better", "same", and "worse", we found no difference in outcome between the two groups: 79.5% (n=31) had satisfactory outcome with ALIF and 80% (n=28) had satisfactory outcome with PLIF. The rate of return to work was no different in the two groups. On radiological assessment, we found two nonunions in the circumferential fusion (PLIF) group (94.3% fusion rate) and indirect evidence of no nonunions in the ALIF group. There was no significant difference between the compensation rate and disability benefit rate between the two groups. There were three complications in ALIF group and four in the PLIF (circumferential) group. On the basis of these results, we conclude that it is possible to treat discogenic back pain by anterior interbody fusion with Hartshill horseshoe cage or with circumferential fusion using instrumented PLIF.

Subsidence of stand-alone cervical cages in anterior interbody fusion: warning

Anterior cervical decompression and fusion with anterior plating of the cervical spine is a well-accepted treatment for cervical radiculopathy. Recently, to minimise the extent of surgery, anterior interbody fusion with cages has become more common. While there are numerous reports on the primary stabilising effects of the different cervical cages, little is known about the subsidence behaviour of such cages in vivo. We retrospectively reviewed eight patients with cervical radiculopathy operated upon with anterior discectomy and fusion with a stand-alone titanium cervical cage. During surgery, only the cartilage portion of the end plate was removed and the cages were filled with autologous cancellous bone graft from the iliac crest. To assess possible subsidence or migration, three different radiographic measurements in the sagittal plane were taken for each case, postoperatively and at the latest follow-up. Subsidence was defined as any change in at least one of our parameters of at least 3 mm. Follow-up time was 12-18 months (average 15 months). Five of the nine fused levels had radiological signs of cage subsidence. No posterior or anterior migration was observed. However, subsidence did not correlate with clinical symptoms in four of the five patients. The remaining patient with signs of subsidence, whose neck pain and neurologic symptoms had regressed in the early postoperative course, suffered recurrence of radiculopathy 6 months after the surgery. Her symptoms were explained by the subsidence of the cage and the subsequent foraminal stenosis observed on the magnetic resonance imaging (MRI) scan. At 15 months' follow-up, her cage was broken. Our preliminary results, so far limited in number, represent a serious warning to the proponents of stand-alone cervical cages