Minimally-invasive technique for transforaminal lumbar interbody fusion (TLIF)

Biportal endoscopic transforaminal lumbar interbody fusion with large cage: a technique without additional spacer portal

BACKGROUND

Large spacers offer numerous advantages such as higher fusion rates and lower subsidence rates. However, due to the anatomical constraints of the approach, the use of large spacers in biportal endoscopic transforaminal lumbar interbody fusion(BE-TLIF) necessitates an additional incision and special instruments for spacer implantation leading to less frequent use.

METHODS

This study has refined several techniques within BE-TLIF. We insert the cage and impact the cage transverse with a special design instrument in the same working portal. This allows for the use of large spacers during BE-TLIF procedures without the need for an auxiliary cage-inserting incision.

CONCLUSION

The technique is a straightforward, safe, and minimally invasive method for inserting large cages in the treatment of lumbar instability.

Full-Endoscopic Posterior Lumbar Interbody Fusion: A Review and Technical Note

Remarkable innovations in spinal endoscopic surgery have broadened its applications over the past 20 years. Full-endoscopic fusions have been widely reported, and several full-endoscopic approaches for interbody fusion have been published. In general, full-endoscopic lumbar interbody fusion (LIF) is called Endo-LIF, and facet-preserving Endo-LIF through the transforaminal route is called trans-Kambin's triangle LIF, which has a relatively longer history than facet-sacrificing Endo-LIF via the posterolateral route. Both approaches can reduce intraoperative and postoperative bleeding. However, there is a higher risk of subsidence and exit nerve root injury. There is no direct decompression in either of the interbody fusions, and additional decompression is required if there is severe lumbar bony canal stenosis. However, the posterior interlaminar approach, which is a well-known standard in full-endoscopic spine surgery, has rarely been applied in the field of endoscopic lumbar fusion surgery. Full-endoscopic posterior LIF (FE-PLIF) via an interlaminar approach can accomplish direct decompression of bony canal stenosis and safe interbody fusion. FE-PLIF via an interlaminar approach demonstrated a longer operation time, less blood loss, and shorter hospitalization duration than minimally invasive transforaminal LIF. FE-PLIF, which can accomplish direct decompression for bony spinal canal stenosis, is superior to other Endo-LIFs. However, FE-PLIF requires technical dexterity to improve efficiency and reduce technical complexity.

Minimally Invasive Transforaminal Interbody Fusion Versus Microdiscectomy Without Fusion for Recurrent Lumbar Disk Herniation: A Prospective Comparative Study

OBJECTIVE

The objective of this study was to compare the clinical outcome of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) versus standard revision diskectomy for recurrent lumbar disk herniation (RLDH).

BACKGROUND

RLDH is the most common cause of redo surgery after a microdiscectomy. Commonly, in patients without evidence of spinal instability, many surgeons would simply redo microdiscectomy, while others proceed to a redo microdiscectomy with arthrodesis. According to the literature, there is no evidence of what the best management of an RLDH would be.

METHODS

This study involved 90 patients who underwent lumbar microdiscectomy in the past and were now experiencing a new lumbar disk herniation for the first time. The patients were divided into two groups, each with 45 patients: group A received standard revision microdiscectomy, whereas group B received revision microdiscectomy with MIS TLIF.The Japanese Orthopaedic Association score, operating time, blood loss, duration of hospital stay, costs, and complications were all prospectively recorded in a database and examined. Back and leg discomfort were measured using the visual analog scale.

RESULTS

The mean total postoperative Japanese Orthopaedic Association score across the groups exhibited no statistically significant difference, nor did the preoperative clinical and epidemiological data. Although postoperative leg pain was comparable in both groups, postoperative lower back pain in group A was much worse than that in group B. Additional revision surgery was necessary for six individuals in group A. Group A had higher rates of dural rupture and postoperative neurological impairment. Group A experienced much less intraoperative blood loss, longer operation times, and postoperative hospital stays.

CONCLUSION

In patients with RLDH, revision microdiscectomy is effective. In comparison with conventional microdiscectomy, MIS TLIF reduces intraoperative risk of dural rupture or neural injury, postoperative incidence of mechanical instability or recurrence, and postoperative lower back pain.

STUDY DESIGN

Prospective, randomized, multicenter, comparative study.

Unilateral biportal endoscopic extreme transforaminal lumbar interbody fusion with large cage combined with endoscopic unilateral pedicle screw fixation for lumbar degenerative diseases: a technical note and preliminary effects

OBJECTIVE

The purpose of the study was to investigate the feasibility and preliminary effects of unilateral biportal endoscopic extreme transforaminal lumbar interbody fusion(UBE-eXTLIF) with large cage combined with endoscopic unilateral pedicle screw fixation for lumbar degenerative diseases.

METHODS

Patients with lumbar degenerative diseases who received UBE-eXTLIF with large cage combined with endoscopic unilateral pedicle screw fixation from June 2022 to July 2022 were retrospectively analyzed, including 4 females and 1 males. The clinical symptoms and signs were consistent with the imaging changes. We recorded operation time, length of postoperative hospital stay, and complications. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and modified Macnab scale was used to evaluate the clinical efficacy at preoperative, postoperative 1 month, and the last follow-up.

RESULTS

The operation was successfully completed in all cases. The operation time was 150-180 min, with an average of 164.60 ± 12.03 min. No serious complications such as dural tears and vascular and nerve injuries occurred during operation. All the patients got out of bed 1-3 days after surgery and were hospitalized 4-5 days after surgery, with an average of 4.20 ± 0.45 days. Preoperative VAS scores of low back pain were 6.20 ± 0.84 and respectively decreased to 2.20 ± 0.45 and 1.40 ± 0.55 at postoperative 1 month and at the last follow-up, and the difference was statistically significant (P < 0.05). Preoperative VAS scores of lower limb pain were 4.60 ± 2.61 and respectively decreased to 1.00 ± 0.71 and 0.60 ± 0.55 at postoperative 1 month and at the last follow-up, and the difference was statistically significant (P < 0.05). Preoperative ODI scores were 62.00 ± 3.16 and respectively decreased to 38.00 ± 1.41 and 32.40 ± 3.29 at postoperative 1 month and at the last follow-up, and the difference was statistically significant (P < 0.05). According to the modified Macnab criteria, the final outcome was excellent in 4 cases and good in 1 case. Five patients could return to normal activities within 3 weeks.

CONCLUSIONS

UBE-eXTLIF with large cage combined with endoscopic unilateral pedicle screw fixation can achieve excellent clinical results and may become a new minimally invasive endoscopic fusion method for lumbar degenerative diseases.

Endoscopic Extreme Transforaminal Lumbar Interbody Fusion With Large Spacers: A Technical Note and Preliminary Report

This report describes a novel endoscopic fusion technique performed with unilateral biportal endoscopy (UBE) that is known as extreme transforaminal lumbar interbody fusion (eXTLIF) and is performed with a large spacer. We also present the short-term results of this procedure. Previous studies reported that minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) could achieve acceptable rates of fusion; therefore, it is often used for treating various degenerative lumbar diseases. Moreover, MIS-TLIF can be performed with a unilateral approach; hence, it is commonly performed with the UBE technique. The biportal endoscopic TLIF procedure is usually performed with a single spacer in the interbody space. It is important to insert the maximum amount of graft material into the preparation site via an autologous bone marrow transplant or any other suitable substance with spacer insertion. Because MIS-TLIF with UBE is performed in water, it might provide an inadequate environment for excellent fusion. Therefore, a modified method was used to increase the surface contact area and insert the maximum amount of bone material with a larger spacer. However, the use of a large spacer necessitates a larger spacer orifice. For this purpose, eXTLIF was performed, which inserts the spacer more laterally compared with the current TLIF position. We report the surgical method and short-term results, which have been satisfactory thus far. [Orthopedics. 2022;45(3):163-168.].

Longitudinal Trends of Patient Demographics and Morbidity of Different Approaches in Lumbar Interbody Fusion: An Analysis Using the American College of Surgeons National Surgical Quality Improvement Program Database

OBJECTIVE

The aims of this study were to determine the time trend of demographics, complications, and outcomes for patients undergoing posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF) or anterior lumbar interbody fusion/lateral lumbar interbody fusion (ALIF/LLIF) and to compare the differences in the time trends between both procedures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients undergoing PLIF/TLIF and ALIF/LLIF procedures. Outcomes were analyzed for differences between 2 time periods in the PLIF/TLIF and ALIF/LLIF cohorts separately (2009-2013 and 2015-2019). Longitudinal time trends of the 2 procedures were determined by difference-in-differences (DID) analysis. Statistical significance was defined as P < 0.05.

RESULTS

For both approaches, there was an increase in age and American Society of Anesthesiologists class over time, accompanied by a significant decrease in blood transfusions and morbidity. The DID analysis showed a greater change in age (DID:-1.8%; P < 0.001), and more patients were rated American Society of Anesthesiologists class 3 (DID: -2.4%; P = 0.033) in the ALIF/LLIF cohort than in the PLIF/TLIF cohort. Length of stay declined significantly over time in both cohorts, with a greater reduction observed for patients who underwent ALIF/LLIF than for patients who underwent PLIF/TLIF (DID: 0.2%; P = 0.014). There were no changes in readmission rates over time in either cohort (PLIF/TLIF DID: 0.6%; P = 0.080; ALIF/LLIF DID: -0.2%; P = 0.696).

CONCLUSIONS

Time trends for PLIF/TLIF and ALIF/LIIF showed a significant increase in the number of older patients with complex medical status undergoing surgery. Despite these trends, there were decreases in overall postoperative morbidity, incidence of blood transfusion, and length of stay, without increasing readmission. These results suggest general improvement in surgical and perioperative management of lumbar fusion over time with greater gains found in ALIF/LLIF-specific care than in PLIF/TLIF.

Ligamentum-preserved/Temporary Preserved Minimally Invasive Transforaminal Lumbar Interbody Fusion for Lumbar Spondylolisthesis: Technical Note and 2-year Follow-up

STUDY DESIGN

Prospective study.

OBJECTIVE

The aim of this study was to prospectively assess the clinical outcomes of modified minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of singlesegment lumbar spondylolisthesis.

SUMMARY OF BACKGROUND DATA

MIS-TLIF is a safe and effective procedure in the treatment of lumbar degenerative disease. To avoid durotomy and nerve root injury, we modified the surgical order of MIS-TLIF such that the interbody fusion procedure was performed before the decompression procedure.

METHODS

One hundred thirty-nine patients with single-segment lumbar spondylolisthesis were separated into two groups. Sixty-seven patients underwent modified MIS-TLIF (group A). In group B, 72 patients underwent routine MIS-TLIF. The Japanese Orthopedic Association (JOA) score and the visual analogue scale (VAS) scores for lower back pain (LBP) and leg pain were assessed during the postoperative follow-up, and the lumbar interbody fusion rate was evaluated by CT scanning.

RESULTS

The mean operative time, incision length, average blood loss, and incision pain level were not significantly different (P  > 0.05) between the two groups. No nerve root or dural injuries were observed in group A. In group B, there were two cases of dural injury and three cases of nerve root injury. One patient experienced temporary numbness and weakness on dorsiflexion of the foot, which recovered in 3 months. No differences were identified between the two groups when postoperative JOA scores, back pain, leg pain VAS scores, or the lumbar interbody fusion rate.

CONCLUSION

Both methods are effective in the treatment of lumbar degenerative disease. Modified MIS-TLIF is a safe and effective procedure that can significantly reduce the occurrence of injury to the dura and nerve root during decompression and the interbody fusion procedure.Level of Evidence: 3.

Perioperative Complications of Minimally Invasive Transforaminal Lumbar Interbody Fusion (MI-TLIF): 10 Years of Experience With MI-TLIF

STUDY DESIGN

A prospective study.

OBJECTIVES

We present a largest study until date performed over a period of 10 years assessing the perioperative complications. The primary aim of this study was to review the incidence of perioperative complications of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in single-level lumbar degenerative diseases.

METHODS

A prospective study performed over a period of 10 years involving 560 patients who underwent single-level lumbar MI-TLIF. Perioperative clinical and radiological parameters, postoperative complications, and satisfactory outcomes in the form of Wang's criteria were evaluated. All patients were scrutinized into 5 different categories based on the descriptive classification for perioperative complications suggested by the authors.

RESULTS

The mean age was 61.8 ± 12.7 years and male to female ratio was 0.8:1. The overall incidence of the perioperative complication was 25.5%. In all, 19.64% patients developed single complication, 4.64% patients were with 2 complications, and 1.25% patients developed 3 complications from the described categories. A total of 16.78% patients developed early (<6 months postsurgery) and 8.75% patients developed late (>6 months postsurgery) complications.

CONCLUSION

This study showed 25.5% incidence of perioperative complications in MI-TLIF for degenerative lumbar disease over a period of 10 years with a higher incidence rate during the initial 3 years of practice. The described classification for perioperative complications is helpful to record, to evaluate and to understand the etiology based on its duration of occurrence in the perioperative period. MI-TLIF is an effective procedure with substantial clinical benefits in the form of excellent to good clinical-radiological outcomes.

Physiologic Decompression of Lumbar Spinal Stenosis Through Anatomic Restoration Using Trans-Kambin Oblique Lateral Posterior Lumbar Interbody Fusion (OLLIF): A Retrospective Analysis

Introduction Lumbar spinal stenosis (LSS) is one of the most common indications for spinal surgery. Traditionally, decompression is achieved by removing bony and ligamentous structures through open surgery. However, recent studies have shown that symptomatic relief can be accomplished in many patients by increasing intervertebral and interpedicular height using fusion alone. In this study, we evaluate whether trans-Kambin oblique lateral lumbar interbody fusion (OLLIF) can effectively and safely relieve symptoms of LSS when an indication for fusion is present. Methods This is a retrospective single surgeon cohort study of 187 patients with LSS who underwent 189 OLLIF procedures between 2012 and August 2, 2019. Inclusion criteria for this study were age >18 years with symptoms of LSS, including pain, sensory, and motor deficits, and an additional indication for fusion, which included spondylolisthesis, degenerative disk disease, disk herniation, or scoliosis. Exclusion criteria were the bony obstruction of the approach, osteogenic spinal canal stenosis, large facet hypertrophy, and listhesis grade II or greater. The primary outcome was a change in the Oswestry Disability Index (ODI) one year after surgery. Secondary outcomes were the resolution of radiculopathy at the first follow-up visit and one year after surgery, complication rates, surgery time, blood loss, and hospital stay. Results ODI improved from 52% pre-op to 37% at the one-year follow-up. At the first follow-up, radiculopathy had resolved in 39% of patients, and 72% of patients experienced improvement of 50% or greater. One year after surgery, radiculopathy had resolved in 52% of patients and 74% experienced improvement of 50% or greater. Single-level surgeries required 56.4±21.5 minutes, with a mean hospital stay of 1.6‑±2.4 days. Nerve irritation occurred in 12% of patients at the first postoperative follow-up and persisted in 6.8% of patients one year after surgery. There was one case each of persistent weakness at one year, infection, and cage subsidence. Conclusion Trans-Kambin OLLIF delivers anatomic restoration of intradiscal and interpedicular distance, which results in physiologic decompression of lumbar spinal stenosis in patients undergoing lumbar fusion for degenerative or herniated disk disease, spondylolisthesis, or scoliosis. Amongst patients with LSS, OLLIF results in significant improvement of radiculopathy and patient-reported disability in the majority of patients with low rates of long-term complications. Unlike other minimally invasive surgery (MIS) fusions, OLLIF can be safely used from T12-S1.

Uniportal Endoscopic Lumbar Interbody Fusion

The cause of radiculopathy is the compression of the nerve root which can be secondary to sliding of the vertebra and reduced disc height. In some patients, decompression alone does not resolve this problem. We describe the uniportal endoscopic transforaminal lumbar interbody fusion technique. Full-endocopic foraminotomy and discectomy are followed by cage implementation and percutaneous instrumentation. The goal of this surgical method is decompression of nerve roots, segment stabilization, disc height, and sagittal alignment restoration. Uniportal endoscopic facet sparing transforaminal transkambin lumbar interbody fusion is a good surgical option to treat degenerative disc disease, mechanical instability, and spondylolisthesis. This method shows favourable clinical outcomes in selected patients.

Using Porcine Cadavers as an Alternative to Human Cadavers for Teaching Minimally Invasive Spinal Fusion: Proof of Concept and Anatomical Comparison

Training surgeons to perform minimally invasive spinal (MIS) surgery is difficult because there are few realistic alternatives to human cadavers which are expensive and require special handling. In this study we report a protocol for performing an MIS training course on a fresh porcine cadaver. We find that the porcine lumbar spine closely resembles the human spine in terms of the vertebral and discal anatomy. Notable differences include a lower disc height and shallower diameter. We obtained fresh porcine cadavers weighing 40-70 kg from local farmers that had been gutted and bled. We position the cadaver prone on a backboard and set up the operating room with biplanar fluoroscopy. During approach and cage insertion, we found that the tactile feedback obtained is realistic and allows surgeons to familiarize themselves with the procedure. Porcine cadavers were also an excellent tool for practicing pedicle screw fixation due to the larger pedicles. Five training courses involving eight surgeons noted that except for anatomical differences the training course was equivalent to training on human cadavers and unanimously preferred training on porcine cadavers to synthetic foam models. We conclude that porcine cadavers are a useful model for training surgeons in MIS surgery. Routine use of porcine cadavers may increase the availability of MIS surgery training.

Endoscopic transforaminal lumbar interbody fusion: a comprehensive review

INTRODUCTION

Endoscopic spine surgery has been developed as a minimally invasive technique for decompression in patients with lumbar disc herniation or lumbar stenosis. Recent reports have described the use of endoscopic technology in lumbar fusion surgeries, especially for transforaminal lumbar interbody fusion (TLIF). This review aimed to summarize the current techniques of endoscopic TLIF and to discuss the benefits, limitations, and future perspectives of endoscopic lumbar fusion surgery.

AREAS COVERED

This review covered the English-language medical literature published in Medline and focused specifically on endoscopic technologies incorporated into minimally invasive TLIF. The endoscopic TLIF techniques are categorized here according to the properties of the endoscope: percutaneous endoscopic TLIF, biportal endoscopic TLIF, and microendoscopic TLIF. Even though most authors have reported favorable clinical and radiological outcomes of endoscopic TLIF, such evidence originates mainly from case series.

EXPERT OPINION

Although the current level of evidence is low and the technical relevance of the technique is controversial, the key concept and early results of endoscopic TLIF are promising. Technical advancements to improve safety and reduce technical complexity, as well as comparative cohort studies and randomized clinical trials with long-term follow-up are required to promote the adoption of endoscopic TLIF in clinical practice.

Clinical and Radiological Outcomes of Modified Mini-Open and Open Transforaminal Lumbar Interbody Fusion: A Comparative Study

Study Design

Retrospective cohort study.

Purpose

To compare the clinical and radiological outcomes of modified mini-open transforaminal lumbar interbody fusion (modMOTLIF) and open TLIF (OTLIF).

Overview of Literature

Minimally invasive transforaminal lumbar interbody fusion (MTLIF) is associated with less blood loss, shorter hospital stay, and less pain. However, it has concerns like increased radiation exposure, steep learning curve, and instrumentation cost. We modified the MTLIF technique by direct freehand insertion of pedicle screws using stab incisions without tubular retractors.

Methods

The study included 24 patients in the modMOTLIF group and 27 patients in the OTLIF group. The average follow-up period was 25.6 months. Clinical outcomes were measured using Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores. Serial X-rays were acquired at 1, 3, 6, 12, and 24 months to assess the union and presence of instability. We also compared blood loss and length of hospital stay in both groups.

Results

All patients showed progressive improvement in VAS and ODI scores. No differences were observed in the preoperative and postoperative ODI and VAS leg scores between the groups. The immediate postoperative VAS back score was significantly higher in the OTLIF group than in the modMOTLIF group; however, no difference was observed at 1 and 2 years. Radiological analysis showed nonunion in one and two patients in the OTLIF and modMOTLIF groups, respectively. The average blood loss was 63 mL in the mod-MOTLIF group and 254 mL in the OTLIF group. The mean hospital stay was 3 days for the modMOTLIF group and 5 days for the OTLIF group.

Conclusions

modMOTLIF was associated with reduced blood loss and shorter hospital stay compared with OTLIF. No significant differences were observed in the clinical and radiological outcomes between the groups after 2 years despite reduced back pain in the immediate postoperative period in patients who underwent modMOTLIF.

Effect of Body Mass Index on Perioperative Outcomes in Minimally Invasive Oblique Lateral Lumbar Interbody Fusion versus Open Fusions: A Multivariant Analysis

Background

Obesity is an increasing public health concern associated with increased perioperative complications and expense in lumbar spine fusions. While open and mini-open fusions such as transforaminal lumbar interbody fusion (TLIF) and minimally invasive TLIF (MIS-TLIF) are more challenging in obese patients, new MIS procedures like oblique lateral lumbar interbody fusion (OLLIF) may improve perioperative outcomes in obese patients relative to TLIF and MIS-TLIF.

Purpose

The purpose of this study is to determine the effects of obesity on perioperative outcomes in OLLIF, MIS-TLIF, and TLIF.

Study design

This is a retrospective cohort study.

Patient sample

We included patients who underwent OLLIF, MIS-TLIF, or TLIF on three or fewer spinal levels at a single Minnesota hospital after conservative therapy had failed. Indications included in this study were degenerative disc disease, spondylolisthesis, spondylosis, herniation, stenosis, and scoliosis.

Outcome measures

We measured demographic information, body mass index (BMI), surgery time, blood loss, and hospital stay.

Methods

We performed summary statistics to compare perioperative outcomes in MIS-TLIF, OLLIF, and TLIF. We performed multivariate regression to determine the effects of BMI on perioperative outcomes controlling for demographics and number of levels on which surgeries were operated.

Results

OLLIF significantly reduces surgery time, blood loss, and hospital stay compared to MIS-TLIF, and TLIF for all levels. MIS-TLIF and TLIF do not differ significantly except for a slight reduction in hospital stay for two-level procedures. On multivariate analysis, a one-point increase in BMI increased surgery time by 0.56 ± 0.47 minutes (p = 0.24) in the OLLIF group, by 2.8 ± 1.43 minutes (p = 0.06) in the MIS-TLIF group, and by 1.7 ± 0.43 minutes (p < 0.001) in the TLIF group. BMI has positive effects on blood loss for TLIF (p < 0.001) but not for OLLIF (p = 0.68) or MIS-TLIF (p = 0.67). BMI does not have significant effects on length of hospital stay for any procedure.

Conclusions

Obesity is associated with increased surgery time and blood loss in TLIF and with increased surgery time in MIS-TLIF. Increased surgery time may be associated with increased perioperative complications and cost. In OLLIF, BMI does not affect perioperative outcomes. Therefore, OLLIF may reduce the disparity in outcomes and cost between obese and non-obese patients.

POSTEROLATERAL, POSTERIOR AND MI-TRANSFORAMINAL LUMBAR INTERBODY FUSION: A STUDY OF 212 CASES

ABSTRACT Objective: Degenerative disc disease is a common problem that could require surgical treatment. The aim of this study was to compare clinical outcomes, complications and benefits associated with intersomatic fusions by the MI-TLIF, PLIF and PLF techniques. Methods: A total of 212 patients were retrospectively reviewed. All patients underwent the same pre- and postoperative clinical evaluations using the Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and SF-36. Follow-ups were performed for at least one year. Inpatient days, complications, blood loss and operative times were equally quantified. Results: Estimated blood loss for MI-TLIF was statistically lower compared to the amount of blood recovered by Cell Saver device on PLIF and PLF groups. Mean surgical time for MI-TLIF were not significantly different compared to PLIF and PLF groups. Inpatient days were significantly lower in the MI-TLIF group, with an average decrease of one day. Four complications were recorded in the PLIF group, 2 in the PLF group, and one in the MI-TLIF group. Analysis of the clinical parameters revealed post-operative improvements at all time points, with the most statistically significant differences occurring at the first six months. Better results were achieved with the MI-TLIF technique. Conclusions: Compared to more invasive techniques, MI-TLIF showed fewer complications, less blood loss and shorter hospitalization times. Longer operative times in this group can be explained by the greater technical complexity and incipient learning curves. Interbody fusion by PLIF, PLF and MI-TLIF provided good clinical outcomes, but faster recovery was obtained with less invasive techniques. Level of evidence: III; Type of study: Retrospective comparative case study.

A Comparison of Anterior and Posterior Lumbar Interbody Fusions: Complications, Readmissions, Discharge Dispositions, and Costs

STUDY DESIGN

Retrospective database review.

OBJECTIVE

To understand medical complication rates, readmission rates, costs, and discharge dispositions in anterior lumbar interbody fusion (ALIFs) versus transforaminal lumbar interbody fusions (TLIFs)/posterior lumbar interbody fusions (PLIFs) for lumbar degenerative disease.

SUMMARY OF BACKGROUND DATA

Indications for ALIFs versus PLIFs can vary, though benefits of anterior approach surgery include full access to the anterior column and ability to place fusion devices.

METHODS

The PearlDiver Database of Medicare records was utilized for this retrospective database review. A study group consisting solely of ALIF procedure patients was selected for. Similarly, a TLIF/PLIF group was selected for. Both groups were queried for comorbidities, 30 and 90-day complication and readmission rates. Additionally, discharge dispositions, and in-hospital/30-day/90-day Medicare reimbursements were determined.

RESULTS

At both 30 and 90 days postoperatively odds of ileus, wound infection, and lower extremity deep venous thrombosis were significantly increased in the ALIF. However, unadjusted rates and adjusted odds of transfusion or dural tear were significantly decreased in the ALIF patients. Odds of 30-day readmission were 4 times higher in ALIF patients. Additionally, 30 and 90-day total costs of care in ALIF patients were significantly increased by approximately $4800 and $5800 respectively, as compared with patients undergoing TLIF/PLIF.

CONCLUSION

Despite higher initial routine discharge rates, readmissions and costs of postoperative care were significantly increased in ALIF procedures. It is necessary to evaluate etiology of degenerative pathology as ALIFs are successful solutions to anterior translational instability and anterior disc slippage, but may not have the best long-term outcomes and may not be cost-effective compared with a TLIF/PLIF. In light of our data, it is important to assess the risks and benefits of the varying approaches, and the necessity to access the anterior column, when deciding on surgical technique to treat lumbar degenerative pathology.

LEVEL OF EVIDENCE

4.

Minimally invasive transforaminal lumbar interbody fusion versus open transforaminal lumbar interbody fusion: a technical description and review of the literature

BACKGROUND

Minimally invasive spine surgery (MISS) has been increasingly advocated during the last decade with new studies being reported every year. Minimally invasive spine procedures, such as minimally invasive transforaminal interbody fusion (MI-TLIF), have been introduced to reduce approach-related muscle trauma, to minimise blood loss, and to achieve faster wound healing, quicker ambulation and earlier patient discharge.

METHODS

The aim of this article was to give a comprehensive review of the available English literature comparing open TLIF with MI-TLIF techniques published or available online between 1990 and 2014 as identified by an electronic database search on http://www.ncbi.nlm.nih.gov/pubmed . Fourteen relevant studies comparing MI-TLIF and open TLIF cohorts could be identified.

RESULTS AND CONCLUSION

MI-TLIF seems to be a valid alternative to open TLIF. Both methods yield good clinical results with similar improvements of Oswestry Disability Index (ODI) and visual analogue scale (VAS) on follow-up. There seems to be no significant differences in clinical outcome and fusion rates on comparison. These results are consistent throughout all reported studies in this review. The most pronounced benefits of MI-TLIF are a significant reduction of blood loss, shorter lengths of hospital stay (LOHS) and lower surgical site infection rates. On the downside, MI-TLIF seems to be associated with significantly higher intraoperative radiation doses, a shallow learning curve, at least in the beginning, longer operating times and potentially more frequent implant failures/cage displacements and revision surgeries.

Minimally Invasive Direct Lateral Interbody Fusion (MIS-DLIF): Proof of Concept and Perioperative Results

BACKGROUND

Minimally invasive direct lateral interbody fusion (MIS-DLIF) is a novel approach for fusions of the lumbar spine. In this proof of concept study, we describe the surgical technique and report our experience and the perioperative outcomes of the first nine patients who underwent this procedure.

STUDY DESIGN/SETTING

In this study we establish the safety and efficacy of this approach. MIS-DLIF was performed on 15 spinal levels in nine patients who failed to respond to conservative therapy for the treatment of a re-herniated disk, spondylolisthesis, or other severe disk disease of the lumbar spine. We recorded surgery time, blood loss, fluoroscopy time, patient-reported pain, and complications.

METHODS

Throughout the MIS-DLIF procedure, the surgeon is aided by biplanar fluoroscopic imaging to place an interbody graft or cage into the disc space through the interpleural space. A discectomy is performed in the same minimally invasive fashion. The procedure is usually completed with posterior pedicle screw fixation.

RESULTS

MIS-DLIF took 44/85 minutes, on average, for 1/2 levels, with 54/112 ml of blood loss, and 0.3/1.7 days of hospital stay. Four of nine patients did not require overnight hospitalization and were discharged two to four hours after surgery. We did not encounter any clinically significant complications. At more than ninety days post surgery, the patients reported a statistically significant reduction of 4.5 points on a 10-point sliding pain scale.

CONCLUSIONS

MIS-DLIF with pedicle screw fixation is a safe and clinically effective procedure for fusions of the lumbar spine. The procedure overcomes many of the limitations of the current minimally invasive approaches to the lumbar spine and is technically straightforward. MIS-DLIF has the potential to improve patient outcomes and reduce costs relative to the current standard of care and therefore warrants further investigation. We are currently expanding this study to a larger cohort and documenting long-term outcome data.

Modified Mini-open Transforaminal Lumbar Interbody Fusion: Description of Surgical Technique and Assessment of Free-hand Pedicle Screw Insertion

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To describe a modified technique for mini-open transforaminal lumbar interbody fusion (TLIF) that improves visualization for decompression, fusion, and freehand pedicle screw insertion. Accuracy of freehand pedicle screw placement with this technique was assessed.

SUMMARY OF BACKGROUND DATA

Mini-open TLIF is a minimally invasive technique that allows limited visualization of the bone and neural anatomy via an expandable tubular retractor inserted through the Wiltse plane. No significant modification that of this technique has been described in detail.

METHODS

In this study, 92 consecutive patients underwent one-level modified mini-open TLIF (MOTLIF). MOTLIF modifications consisted of (i) transmuscular dissection through the multifidus muscle rather than intermuscular dissection in the Wiltse plane; (ii) microsurgical detachment of multifidus from the facet rather than muscle dilation; (iii) en bloc total facetectomy (unilateral or bilateral, as needed for decompression); (iv) facet autograft used for interbody fusion; and (v) solid pedicle screws placed bilaterally by a freehand technique under direct vision.

RESULTS

The mean age was 53 years. Mean follow-up was 35 months (minimum 2 yrs). By 6 months, mean Visual Analog Scale for back and leg pain had improved from 51 to 19 and from 58 to 17, respectively, and mean Oswestry Disability Index (ODI) improved from 53 to 16. These improvements persisted at 2 years. Solid fusion, defined by computed tomography at 1 year, was achieved in 88.1%, whereas satisfactory fusion was achieved in 95.2% of patients. Pedicle screws were accurately placed in 335 of 336 imaged pedicles (pedicle breach grades: 91.1% grade 1; 8.6% grade 2; and 0.3% grade 3). Mean fluoroscopy time was 29.3 seconds.

CONCLUSION

MOTLIF is a safe and effective minimally invasive technique with a high fusion rate. It allows accurate pedicle screw placement by a freehand technique. By eliminating bi-planar fluoroscopy, it helps reduce radiation exposure. This is the largest published report of mini-open TLIF to date.

LEVEL OF EVIDENCE

4.

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.

Transforaminal Lumbar Interbody Fusion in Degenerative Disk Disease and Spondylolisthesis Grade I: Minimally Invasive Versus Open Surgery

BACKGROUND

Interbody fusion represents an efficient surgical treatment in degenerative lumbar disease, achieving satisfying outcome in >90% of cases. Various studies have affirmed the advantages of percutaneous and minimally invasive techniques with regard to minimized damage on soft tissues during surgical procedure, but their efficacy in comparison with the classic open surgical procedures has not yet been demonstrated.

MATERIALS AND METHODS

This is a retrospective study. We compared 30 consecutive patients affected by disk degenerative disease or grade I degenerative spondylolisthesis that were treated with minimally invasive transforaminal lumbar interbody fusion (mini-TLIF) to a group of 34 consecutive patients presenting similar pathologic findings and demographic characteristics that underwent interbody fusion by traditional open approach (open-TLIF). All patients were treated between 2006 and 2010. Patients' mean age was 46 years (min 28-max 56) and 51 years (min 32-max 58), respectively. Mean follow-up was 23 months (min 12-max 38) and 25 months (min 12-max 40), respectively. Clinical evaluation was performed by using Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) questionnaires. Radiographic evaluation was performed on standing and dynamic x-rays before operation and at final follow-up.

RESULTS

There was a statistically significant improvement in clinical scores (VAS and ODI) in both groups. Early postoperative VAS score was significantly lower in the mini-TLIF group. Mean hospital stay and mean blood loss were significantly higher in the open-TLIF group than in the mini-TLIF group (7.4 vs. 4.1 d and 620 vs. 230 mL, respectively). Surgical time length of the procedure was higher in the mini-TLIF group. There were no major neurological complications in any of the patients. At final follow-up, radiographic evaluation showed good implant stability in both groups.

CONCLUSIONS

Mini-TLIF is a safe and efficient procedure and, when correctly and carefully performed, can reach good results, similar to those obtained with traditional open surgical techniques, even though it may require a longer surgical time at least during the first stages of the learning curve. Reduced surgical invasiveness, short hospital stay, and limited blood loss represent the major advantages of minimally invasive technique.

MICROSURGICAL LANDMARKS IN MINIMALLY INVASIVE TRANSFORAMINAL LUMBAR INTERBODY FUSION

Microsurgical landmarks of the facet joint complex were defined to provide guidance and security within the tubular retractor during transforaminal surgery. A retrospective observational study was performed in segments L4-L5 by the left side approach. Microsurgical relevant photos, anatomical models and drawing were used to expose the suggested landmarks. The MI-TLIF technique has advantages compared with conventional open TLIF technique, however minimally invasive technique implies lack of security for the surgeon due to the lack of defined microanatomical landmarks compared to open spine surgery, and disorientation within the tubular retractor, the reason why to have precise microsurgical references and its recognition within the surgical field provide speed and safety when performing minimally invasive technique.

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.

Economic Performance of Oblique Lateral Lumbar Interbody Fusion (OLLIF) with a Focus on Hospital Throughput Efficiency

Oblique lateral lumbar interbody fusion (OLLIF) is a minimally invasive lumbar surgery. Differences in resource consumption between open spinal surgeries, transformational lumbar interbody fusions (TLIF) and OLLIF, are not documented. We monetize quantifiable differences in resource utilization between the two procedures. A retrospective review of 124 surgeries was performed (OLLIF=69, TLIF=55). Standard conversion factors were used and values reported based on the levels (1-4) addressed at surgery. One level surgery time (OLLIF 62.9 vs. TLIF 134.9 minutes) and surgical expense (OLLIF $5,253 vs. TLIF $11,264) were reduced in the OLLIF population. Inpatient costs (OLLIF $5,712 vs. TLIF $9,271) and length of stay (LOS) were also reduced (OLLIF 2.6 vs. TLIF 4.2 days). Per case, reduced resource consumption suggests lower total hospital costs. Reduced surgical time and LOS can result in greater patient throughput per operating room and patient bed for OLLIF patients in hospitals that have resourced constrained environments.

Minimally invasive unilateral versus bilateral technique in performing single-segment pedicle screw fixation and lumbar interbody fusion

Purpose

The minimally invasive transforaminal lumbar interbody fusion procedure with percutaneous pedicle screws was adopted in clinical practice, but the choice between a unilateral pedicle screw (UPS) or bilateral pedicle screw (BPS) fixation after lumbar fusion remains controversial. The purpose of the present retrospective study was to compare the clinical outcomes and radiological results of unilateral and bilateral pedicle screw fixations.

Methods

The retrospective study recruited seventy-eight patients with a single-level pedicle screw fixation and lumbar interbody fusion at L4–L5 or L5–S1 from January 2010 to January 2013. The patients were treated with MIS TLIF with BPS fixation, and since May 2012, all patients were treated with UPS fixation. The perioperative outcomes including operative time, blood loss, hospital-stay length, and complication rates were accessed. Radiological outcomes regarding fusion were determined with the Bridwell grading system. Clinical outcomes were evaluated with the Oswestry Disability Index (ODI) and visual analog scale (VAS) during the mean follow-up of 2 years.

Results

According to perioperative assessments, the operative time was significantly shorter for group UPS (84.7 ± 6.4 min) than for group BPS (103.6 ± 10.6 min; p < 0.0001), and similar results were found with regard to the mean blood loss (UPS, 96.3 ± 17.5; BPS, 137.4 ± 32.9, p < 0.0001). With regard to the hospital-stay period, though the UPS group seems shorter, there is no statistical significance (UPS, 10.0 ± 2.1; BPS, 10.4 ± 2.4, p = 0.428). There were four in the BPS group and six in the UPS group defined as unfused at 6 months pest-operative, but at 12 months post-surgery, all patients achieved solid fusion. Regarding clinical outcomes, the VAS and ODI scores were significantly lower in the UPS group than the BPS group at 7 days post-surgery, but there was no difference at 1 month post-surgery and during the later follow-up.

Conclusion

There was no difference between the UPS and BPS flexion techniques about the clinical outcomes at 24 months post-surgery. However, because the UPS involves a shorter surgical time, less blood loss, faster pain relief, and faster functional recovery, UPS might be more suitable in performing single-segment pedicle screw fixation and lumbar interbody fusion.

Stability of transforaminal lumbar interbody fusion in the setting of retained facets and posterior fixation using transfacet or standard pedicle screws

BACKGROUND CONTEXT

The transforaminal lumbar interbody fusion (TLIF) technique supplements posterior instrumented lumbar spine fusion and has been tested with different types of screw fixation for stabilization. Transforaminal lumbar interbody fusion is usually placed through a unilateral foraminal approach after unilateral facetectomy, although extraforaminal entry allows the facet to be spared.

PURPOSE

To characterize the biomechanics of L4-L5 lumbar motion segments instrumented with bilateral transfacet pedicle screw (TFPS) fixation versus bilateral pedicle screw-rod (PSR) fixation in the setting of intact facets and native disc or after discectomy and extraforaminal placement of a TLIF technology graft.

STUDY DESIGN

Human cadaveric lumbar spine segments were biomechanically tested in vitro to provide a nonpaired comparison of four configurations of posterior and interbody instrumentation.

METHODS

Fourteen human cadaveric spine specimens (T12-S1) underwent standard pure moment flexibility tests with intact L4-L5 disc and facets. Seven were studied with intact discs, after TFPS fixation, and then with TLIF and TFPS fixation. The others were studied with intact discs, after PSR fixation, and then combined with extraforaminally placed TLIF. Loads were applied about anatomic axes to induce flexion-extension, lateral bending, and axial rotation. Three-dimensional specimen motion in response to applied loads during flexibility tests was determined. A nonpaired comparison of the four configurations of posterior and interbody instrumentation was made.

RESULTS

Transfacet pedicle screw and PSR, with or without TLIF, significantly reduced range of motion during all directions of loading. Transfacet pedicle screw provided greater stability than PSR in all directions of motion except lateral bending. In flexion, TFPS was more stable than PSR (p=.042). A TLIF device provided less stability than the intact disc in constructs with TFPS and PSR.

CONCLUSIONS

These results suggest that fixation at L4-L5 with TFPS is a promising alternative to PSR, with or without TLIF. A TLIF device was less stable than the native disc with both methods of instrumentation presumably because of a fulcrum effect from a relatively small footplate. Additional interbody support may be considered for improved biomechanics with TLIF.

Minimally invasive procedures on the lumbar spine

Degenerative disease of the lumbar spine is a common and increasingly prevalent condition that is often implicated as the primary reason for chronic low back pain and the leading cause of disability in the western world. Surgical management of lumbar degenerative disease has historically been approached by way of open surgical procedures aimed at decompressing and/or stabilizing the lumbar spine. Advances in technology and surgical instrumentation have led to minimally invasive surgical techniques being developed and increasingly used in the treatment of lumbar degenerative disease. Compared to the traditional open spine surgery, minimally invasive techniques require smaller incisions and decrease approach-related morbidity by avoiding muscle crush injury by self-retaining retractors, preventing the disruption of tendon attachment sites of important muscles at the spinous processes, using known anatomic neurovascular and muscle planes, and minimizing collateral soft-tissue injury by limiting the width of the surgical corridor. The theoretical benefits of minimally invasive surgery over traditional open surgery include reduced blood loss, decreased postoperative pain and narcotics use, shorter hospital length of stay, faster recover and quicker return to work and normal activity. This paper describes the different minimally invasive techniques that are currently available for the treatment of degenerative disease of the lumbar spine.

Perioperative complications related to minimally invasive transforaminal lumbar fusion: evaluation of 204 operations on lumbar instability at single center

BACKGROUND CONTEXT

Minimally invasive transforaminal lumbar fusion (MIS-TLIF) has demonstrated efficacy in the treatment of lumbar degenerative diseases. The reported incidence of perioperative complications associated with MIS-TLIF surgery is highly variable. Studies concerning perioperative complications in broad patient populations are quite rare. This study analyzes a retrospectively collected database of patients who underwent an MIS-TLIF surgery at a single center.

PURPOSE

To determine the incidence of perioperaive complications with MIS-TLIF procedure based on our definition of Type I and II perioperative complications.

STUDY DESIGN

Retrospective cohort study; a review of complications.

PATIENT SAMPLE

The sample comprises 204 patients who underwent MIS-TLIF for the treatment of lumbar degenerative diseases.

OUTCOME MEASURES

Type I complication including all medical adverse events without direct connection to the specific surgical procedure performed. Type II complication including adverse events with direct connection to the surgical procedure performed.

METHODS

A total of 204 MIS-TLIF surgeries on lumbar instability or spondylolisthesis, performed between June 2007 and July 2012, were examined in a retrospective study. A complication classification based on the relation to the surgical procedure and the effect duration was used. Perioperative complications until 1 month postoperatively were reviewed for the patients.

RESULTS

The study group comprised 204 patients (106 women, 98 men; mean age at surgery, 52.4 years; age range, 39-84 years). Overall, there were 75 perioperative complications in 204 patients (36.76%). Only one complication occurred in 54 patients. Nine patients had two complications. One patient had three complications. The incidence of perioperative complication was 31.37% (64/204 patients) in the MIS-TLIF operations. Of all complications, seven (9.33%) were classified as persistent complications and 68 (90.67%) were classified as transient complications. The incidence of Type I and II complications were 13.73% and 23.04%, respectively.

CONCLUSIONS

Minimally invasive transforaminal lumbar fusion has gained popularity as a procedure for the treatment of lumbar instability or spondylolisthesis, with similar complications as in the open surgery. Transient sensory disturbance was the most common complication in this series.

Disc space preparation in transforaminal lumbar interbody fusion: a comparison of minimally invasive and open approaches

BACKGROUND

Minimally invasive surgical (MIS) approaches to transforaminal lumbar interbody fusion (TLIF) have been developed as an alternative to the open approach. However, concerns remain regarding the adequacy of disc space preparation that can be achieved through a minimally invasive approach to TLIF.

QUESTIONS/PURPOSES

The purpose of this cadaver study is to compare the adequacy of disc space preparation through MIS and open approaches to TLIF. Specifically we sought to compare the two approaches with respect to (1) the time required to perform a discectomy and the number of endplate violations; (2) the percentage of disc removed; and (3) the anatomic location where residual disc would remain after discectomy.

METHODS

Forty lumbar levels (ie, L1-2 to L5-S1 in eight fresh cadaver specimens) were randomly assigned to open and MIS groups. Both surgeons were fellowship-trained spine surgeons proficient in the assigned approach used. Time required for discectomy, endplate violations, and percentage of disc removed by volume and mass were recorded for each level. A digital imaging software program (ImageJ; US National Institutes of Health, Bethesda, MD, USA) was used to measure the percent disc removed by area for the total disc and for each quadrant of the endplate.

RESULTS

The open approach was associated with a shorter discectomy time (9 versus 12 minutes, p = 0.01) and fewer endplate violations (one versus three, p = 0.04) when compared with an MIS approach, percent disc removed by volume (80% versus 77%, p = 0.41), percent disc removed by mass (77% versus 75%, p = 0.55), and percent total disc removed by area (73% versus 71%, p = 0.63) between the open and MIS approaches, respectively. The posterior contralateral quadrant was associated with the lowest percent of disc removed compared with the other three quadrants in both open and MIS groups (50% and 60%, respectively).

CONCLUSIONS

When performed by a surgeon experienced with MIS TLIF, MIS and open approaches are similar in regard to the adequacy of disc space preparation. The least amount of disc by percentage is removed from the posterior contralateral quadrant regardless of the approach; surgeons should pay particular attention to this anatomic location during the discectomy portion of the procedure to minimize the likelihood of pseudarthrosis.

Surgeons' exposure to radiation in single- and multi-level minimally invasive transforaminal lumbar interbody fusion; a prospective study

Although minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has widely been developed in patients with lumbar diseases, surgeons risk exposure to fluoroscopic radiation. However, to date, there is no studies quantifying the effective dose during MIS-TLIF procedure, and the radiation dose distribution is still unclear. In this study, the surgeons' radiation doses at 5 places on the bodies were measured and the effective doses were assessed during 31 consecutive 1- to 3-level MIS-TLIF surgeries. The operating surgeon, assisting surgeon, and radiological technologist wore thermoluminescent dosimeter on the unshielded thyroid, chest, genitals, right middle finger, and on the chest beneath a lead apron. The doses at the lens and the effective doses were also calculated. Mean fluoroscopy times were 38.7, 53.1, and 58.5 seconds for 1, 2, or 3 fusion levels, respectively. The operating surgeon's mean exposures at the lens, thyroid, chest, genitals, finger, and the chest beneath the shield, respectively, were 0.07, 0.07, 0.09, 0.14, 0.32, and 0.05 mSv in 1-level MIS-TLIF; 0.07, 0.08, 0.09, 0.18, 0.34, and 0.05 mSv in 2-level; 0.08, 0.09, 0.14, 0.15, 0.36, and 0.06 mSv in 3-level; and 0.07, 0.08, 0.10, 0.15, 0.33, and 0.05 mSv in all cases. Mean dose at the operating surgeon's right finger was significantly higher than other measurements parts (P<0.001). The operating surgeon's effective doses (0.06, 0.06, and 0.07 mSv for 1, 2, and 3 fusion levels) were low, and didn't differ significantly from those of the assisting surgeon or radiological technologist. Revision MIS-TLIF was not associated with higher surgeons' radiation doses compared to primary MIS-TLIF. There were significantly higher surgeons' radiation doses in over-weight than in normal-weight patients. The surgeons' radiation exposure during MIS-TLIF was within the safe level by the International Commission on Radiological Protection's guidelines. The accumulated radiation exposure, especially to surgeon's hands, should be carefully monitored.

Endoscopy-assisted posterior lumbar interbody fusion in a single segment

Posterior lumbar interbody fusion (PLIF) has been routinely performed for the treatment of lumbar segmental lesions. However, traditional PLIF procedures can result in a variety of approach-related morbidities. The purpose of this study was to determine the efficacy of endoscopy-assisted PLIF in lumbar arthrodesis. From July 2005 to May 2007, a total of 56 patients underwent PLIF, including 24 endoscopy-assisted operations (endoscopic group) and 32 traditional open operations (open group). The perioperative data, clinical outcomes and radiographic results were compared. The intraoperative bleeding volume, postoperative drainage volume, intraoperative and postoperative allogeneic blood transfusion volumes, values for C-reactive protein and erythrocyte sedimentation rate on postoperative day 3 and postoperative hospitalization days were decreased in the endoscopic group (p<0.05), while the operative time was longer than that of the open group (p=0.026). According to the Visual Analog Scale for pain, the postoperative low back pain score in the endoscopic group was lower than that observed in the open group (p<0.05). In the endoscopic group, the excellent and good outcome rate was 87.5%, the incidence of complications was 8.3%, and the intervertebral fusion rate was 100%. There were no significant differences for these outcomes when compared with the open group (p>0.05). Endoscopy-assisted PLIF can achieve a clinical efficacy similar to that of traditional open operations while minimizing destruction to adjacent tissues. This technique is safe and is characterized by less bleeding, less tissue trauma, decreased postoperative pain, rapid recovery, and a shorter postoperative hospital stay.

The effect of surgical level on self-reported clinical outcomes after minimally invasive transforaminal lumbar interbody fusion: L4-L5 versus L5-S1

OBJECTIVE

The anatomic and biomechanical aspects of the L5-S1 level present unique operative challenges compared with the L4-L5 level. However, it has not been determined if self-reported outcomes and complications are different between patients treated with a minimally invasive transforaminal lumbar interbody fusion at these specific levels.

METHODS

There were 36 consecutive patients identified who were treated with a minimally invasive transforaminal lumbar interbody fusion procedure. Surgical indications included spondylolisthesis (grade 1 or 2) and degenerative disk disease with associated clinical symptoms. Patients completed a visual analog scale (VAS) for their back and leg and Oswestry Disability Index preoperatively and postoperatively. Outcomes were compared between patients with L4-L5 involvement and patients with L5-S1 involvement. In all patients, fusion was evaluated by dynamic view flexion and extension views at 1 year. In all patients with indeterminate results or incomplete imaging, computed tomography was performed to evaluate for bridging bone and stable hardware positioning.

RESULTS

The surgical indications between the 2 groups were similar (χ(2) = 0.089, df = 2, P = 0.956). There was no significant difference in mean operating time, intraoperative blood loss, and hospital stay (P = 0.937, 0.627, and 0.587). There was no significant difference in the long-term postoperative questionnaire results (P = 0.819 for VAS [back], 0.626 for VAS [leg], and 0.962 for Oswestry Disability Index) or the mean preoperative to postoperative change in Cobb angle (P = 0.626) between the 2 groups. Two complications, one in each group, were a rash from an antibiotic and postoperative nausea.

CONCLUSIONS

Despite differences in biomechanics and unique anatomic challenges at the L5-S1 interspace, there is no difference in self-reported outcomes for patients treated with minimally invasive transforaminal lumbar interbody fusion at the L4-L5 level compared with the L5-S1 level.

Clinical outcomes of minimally invasive versus open approach for one-level transforaminal lumbar interbody fusion at the 3- to 4-year follow-up

PURPOSE

Supporters of minimally invasive approaches for transforaminal lumbar interbody fusion (TLIF) have reported short-term advantages associated with a reduced soft tissue trauma. Nevertheless, mid- and long-term outcomes and specifically those involving physical activities have not been adequately studied. The aim of this study was to compare the clinical outcomes of mini-open versus classic open surgery for one-level TLIF, with an individualized evaluation of the variables used for the clinical assessment.

METHODS

A prospective cohort study was conducted of 41 individuals with degenerative disc disease who underwent a one-level TLIF from January 2007 to June 2008. Patients were randomized into two groups depending on the type of surgery performed: classic open (CL-TLIF) group and mini-open approach (MO-TLIF) group. The visual analog scale (VAS), North American Spine Society (NASS) Low Back Pain Outcome instrument, Oswestry Disability Index (ODI) and the Short Form 36 Health Survey (SF-36) were used for clinical assessment in a minimum 3-year follow-up (36-54 months).

RESULTS

Patients of the MO-TLIF group presented lower rates of lumbar (p = 0.194) and sciatic pain (p = 0.427) and performed better in daily life activities, especially in those requiring mild efforts: lifting slight weights (p = 0.081), standing (p = 0.097), carrying groceries (p = 0.033), walking (p = 0.069) and dressing (p = 0.074). Nevertheless, the global scores of the clinical questionnaires showed no statistical differences between the CL-TLIF and the MO-TLIF groups.

CONCLUSIONS

Despite an improved functional status of MO-TLIF patients in the short term, the clinical outcomes of mini-open TLIF at the 3- to 4-year follow-up showed no clinically relevant differences to those obtained with open TLIF.

Radiographic Results of Minimally Invasive (MIS) Lumbar Interbody Fusion (LIF) Compared with Conventional Lumbar Interbody Fusion

OBJECTIVE

To evaluate the radiographic results of minimally invasive (MIS) anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF).

METHODS

Twelve and nineteen patients who underwent MIS-ALIF, MIS-TLIF, respectively, from 2006 to 2008 were analyzed with a minimum 24-months' follow-up. Additionally, 18 patients treated with single level open TLIF surgery in 2007 were evaluated as a comparative group. X-rays and CT images were evaluated preoperatively, postoperatively, and at the final follow-up. Fusion and subsidence rates were determined, and radiographic parameters, including lumbar lordosis angle (LLA), fused segment angle (FSA), sacral slope angle (SSA), disc height (DH), and foraminal height (FH), were analyzed. These parameters were also compared between the open and MIS-TLIF groups.

RESULTS

In the MIS interbody fusion group, statistically significant increases were observed in LLA, FSA, and DH and FH between preoperative and final values. The changes in LLA, FSA, and DH were significantly increased in the MIS-ALIF group compared with the MIS-TLIF group, but SSA and FH were not significantly different. No significant differences were seen between open and MIS-TLIF except for DH. The interbody subsidence and fusion rates of the MIS groups were 12.0±4% and 96%, respectively.

CONCLUSION

Radiographic results of MIS interbody fusion surgery are as favorable as those with conventional surgery regarding fusion, restoration of disc height, foraminal height, and lumbar lordosis. MIS-ALIF is more effective than MIS-TLIF for intervertebral disc height restoration and lumbar lordosis.

The future of spine surgery: New horizons in the treatment of spinal disorders

Background and Methods:

As with any evolving surgical discipline, it is difficult to predict the future of the practice and science of spine surgery. In the last decade, there have been dramatic developments in both the techniques as well as the tools employed in the delivery of better outcomes to patients undergoing such surgery. In this article, we explore four specific areas in spine surgery: namely the role of minimally invasive spine surgery; motion preservation; robotic-aided surgery and neuro-navigation; and the use of biological substances to reduce the number of traditional and revision spine surgeries.

Results:

Minimally invasive spine surgery has flourished in the last decade with an increasing amount of surgeries being performed for a wide variety of degenerative, traumatic, and neoplastic processes. Particular progress in the development of a direct lateral approach as well as improvement of tubular retractors has been achieved. Improvements in motion preservation techniques have led to a significant number of patients achieving arthroplasty where fusion was the only option previously. Important caveats to the indications for arthroplasty are discussed. Both robotics and neuro-navigation have become further refined as tools to assist in spine surgery and have been demonstrated to increase accuracy in spinal instrumentation placement. There has much debate and refinement in the use of biologically active agents to aid and augment function in spine surgery. Biological agents targeted to the intervertebral disc space could increase function and halt degeneration in this anatomical region.

Conclusions:

Great improvements have been achieved in developing better techniques and tools in spine surgery. It is envisaged that progress in the four focus areas discussed will lead to better outcomes and reduced burdens on the future of both our patients and the health care system.

Influence of surgical experience on the efficiency of discectomy in TLIF: a cadaveric testing in 40 levels

STUDY DESIGN

Cadaveric study.

OBJECTIVE

The purpose of this study was to assess the influence of surgical experience on the efficiency of lumbar discectomy in open transforaminal lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

There is limited knowledge about the efficiency of discectomy among surgeons. As a first study, we are evaluating the effect of surgical experience on it.

METHODS

Manual and powered discectomies were randomized and performed by 3 attending spine surgeons and 2 clinical spine fellows. Each discectomy procedure was analyzed for the area of complete endplate preparation, total elapsed time, and number of instrument passes. The surface area of discectomy at each endplate was measured utilizing digital imaging and the appropriate software. For the purpose of the analysis, the superior and the inferior endplates were divided into ipsilateral and contralateral halves, and each half was further divided into ventral and dorsal quadrants. Each quadrant was analyzed in a blinded manner by 2 observers.

RESULTS

A total of 40 discectomies were performed on 9 fresh-frozen cadaveric torsos between the levels T12 and S1. A powered discectomy device was used in levels 9 and 11 by the attendings. Manual discectomy was performed in 11 levels by the spine fellows and 9 by the spine attendings. No significant difference was observed between the spine fellows and spine attendings when the manual instruments were used (P = 0.924). However, the spine attending surgeon group had a significantly increased total area of discectomy compared with the fellows (P = 0.003). No significant difference was observed between the groups when instrument passes or the total elapsed time were compared either utilizing the manual or the powered technique.

CONCLUSIONS

Our results demonstrate that a satisfactory discectomy may be performed by surgeons with relatively less surgical experience in the transforaminal approach using a powered discectomy device.

Treatment of multilevel degenerative lumbar spinal stenosis with spondylolisthesis using a combination of microendoscopic discectomy and minimally invasive transforaminal lumbar interbody fusion

Degenerative lumbar spinal stenosis (DLSS) has become increasingly common and is characterized by multilevel disc herniation and lumbar spondylolisthesis, which are difficult to treat. The current study aimed to evaluate the short-term clinical outcomes and value of the combined use of microendoscopic discectomy (MED) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for the treatment of multilevel DLSS with spondylolisthesis, and to compare the combination with traditional posterior lumbar interbody fusion (PLIF). A total of 26 patients with multilevel DLSS and spondylolisthesis underwent combined MED and MI-TLIF surgery using a single cage and pedicle rod-screw system. These cases were compared with 27 patients who underwent traditional PLIF surgery during the same period. Data concerning incision length, surgery time, blood loss, time of bed rest and Oswestry Disability Index (ODI) score prior to and following surgery were analyzed statistically. Statistical significance was reached in terms of incision length, blood loss and the time of bed rest following surgery (P<0.05), but there was no significant difference between the surgery time and ODI scores of the two groups. The combined use of MED and MI-TLIF has the advantages of reduced blood loss, less damage to the paraspinal soft tissue, shorter length of incision, shorter bed rest time, improved outcomes and shorter recovery times and has similar short-term clinical outcomes to traditional PLIF.