Minimally invasive lumbar fusion

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.

Comparing miniopen and minimally invasive transforaminal interbody fusion in single-level lumbar degeneration

Degenerative diseases of the lumbar spine, which are common among elderly people, cause back pain and radicular symptoms and lead to a poor quality of life. Lumbar spinal fusion is a standardized and widely accepted surgical procedure used for treating degenerative lumbar diseases; however, the classical posterior approach used in this procedure is recognized to cause vascular and neurologic damage of the lumbar muscles. Various studies have suggested that using the minimally invasive transforaminal interbody fusion (TLIF) technique provides long-term clinical outcomes comparable to those of open TLIF approaches in selected patients. In this study, we compared the perioperative and short-term advantages of miniopen, MI, and open TLIF. Compared with open TLIF, MI-TLIF and miniopen TLIF were associated with less blood loss, shorter hospital stays, and longer operative times; however, following the use of these procedures, no difference in quality of life was measured at 6 months or 1 year. Whether miniopen TLIF or MI-TLIF can replace traditional TLIF as the surgery of choice for treating degenerative lumbar deformity remains unclear, and additional studies are required for validating the safety and efficiency of these procedures.

A meta-analysis of unilateral versus bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion

STUDY DESIGN

Meta-analysis.

BACKGROUND

Bilateral pedicle screw fixation (PS) after lumbar interbody fusion is a widely accepted method of managing various spinal diseases. Recently, unilateral PS fixation has been reported as effective as bilateral PS fixation. This meta-analysis aimed to comparatively assess the efficacy and safety of unilateral PS fixation and bilateral PS fixation in the minimally invasive (MIS) lumbar interbody fusion for one-level degenerative lumbar spine disease.

METHODS

MEDLINE/PubMed, EMBASE, BIOSIS Previews, and Cochrane Library were searched through March 30, 2014. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on unilateral versus bilateral PS fixation in MIS lumbar interbody fusion that met the inclusion criteria and the methodological quality standard were retrieved and reviewed. Data on participant characteristics, interventions, follow-up period, and outcomes were extracted from the included studies and analyzed by Review Manager 5.2.

RESULTS

Six studies (5 RCTs and 1 CCT) involving 298 patients were selected. There were no significant differences between unilateral and bilateral PS fixation procedures in fusion rate, complications, visual analogue score (VAS) for leg pain, VAS for back pain, Oswestry disability index (ODI). Both fixation procedures had similar length of hospital stay (MD = 0.38, 95% CI = -0.83 to 1.58; P = 0.54). In contrast, bilateral PS fixation was associated with significantly more intra-operative blood loss (P = 0.002) and significantly longer operation time (P = 0.02) as compared with unilateral PS fixation.

CONCLUSIONS

Unilateral PS fixation appears as effective and safe as bilateral PS fixation in MIS lumbar interbody fusion but requires less operative time and causes less blood loss, thus offering a simple alternative approach for one-level lumbar degenerative disease.

Good outcomes of percutaneous fixation of spinal fractures in ankylosing spinal disorders

INTRODUCTION

The ankylosed spine is prone to trauma even with after application of force at low energy levels. Multi-level vertebral bony fusions produce long lever arms, susceptible to fracture, with an increased risk of neurological injury. Additional problems result from delayed presentation and osteoporosis. These patients are also often at high risk of complications, making conventional open spinal surgery less appealing. We present the outcomes of percutaneous fixation and its advantages in this high risk group of patients.

METHODS

A retrospective review of a series of 10 patients with a diagnosis of either ankylosing spondylitis or diffuse idiopathic skeletal hyperostosis (DISH). All patients had sustained a spinal fracture between January 2009 and January 2013 and underwent percutaneous fixation using Medtronic longitude system (Minneapolis, USA) with Polyaxial screws. All were followed up with outcomes, complications and functional scores (Oswestry Disability Index (ODI) and Pain Visual Analogue scores (VAS).

RESULTS

The mean patient age was 68. There was a delayed presentation in seven patients, of which two presented with neurological compromise. The neurological deficit did not change with surgery and there were no neurological complications as a result of surgery. The mean length of stay was 24 days, with no direct surgical complications. The mean drop in haemoglobin level was 2.1, with three patients requiring a blood transfusion. The patients were followed up to a mean of 22 months, with a mean ODI of 16 and pain VAS of 1.1. At the time of follow up, two patients had died with no loss to follow up.

DISCUSSION

Even minor trauma can result in fracture in the ankylosed spine, requiring a high index of suspicion from the physician. The risks of missing such a fracture are significant neurological injury. The biomechanics of the spine are significantly altered, and treatment is demanding. We propose that minimally invasive spinal surgery can achieve good outcomes, low complication rates and high rates of satisfaction.

Systematic review and meta-analysis of minimally invasive transforaminal lumbar interbody fusion rates performed without posterolateral fusion

The need for posterolateral fusion (PLF) in addition to interbody fusion during minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) has yet to be established. Omitting a PLF significantly reduces overall surface area available for achieving a solid arthrodesis, however it decreases the soft tissue dissection and costs of additional bone graft. The authors sought to perform a meta-analysis to establish the fusion rate of MIS TLIF performed without attempting a PLF. We performed an extensive Medline and Ovid database search through December 2010 revealing 39 articles. Inclusion criteria necessitated that a one or two level TLIF procedure was performed through a paramedian MIS approach with bilateral posterior pedicle screw instrumentation and without posterolateral bone grafting. CT scan verified fusion rates were mandatory for inclusion. Seven studies (case series and case-controls) met inclusion criteria with a total of 408 patients who underwent MIS TLIF as described above. The mean age was 50.7 years and 56.6% of patients were female. A total of 78.9% of patients underwent single level TLIF. Average radiographic follow-up was 15.6 months. All patients had local autologous interbody bone grafting harvested from the pars interarticularis and facet joint of the approach side. Either polyetheretherketone (PEEK) or allograft interbody cages were used in all patients. Overall fusion rate, confirmed by bridging trabecular interbody bone on CT scan, was 94.7%. This meta-analysis suggests that MIS TLIF performed with interbody bone grafting alone has similar fusion rates to MIS or open TLIF performed with interbody supplemented with posterolateral bone grafting and fusion.

Minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis and degenerative spondylosis: 5-year results

BACKGROUND

Multiple studies have reported favorable short-term results after treatment of spondylolisthesis and other degenerative lumbar diseases with minimally invasive transforaminal lumbar interbody fusion. However, to our knowledge, results at a minimum of 5 years have not been reported.

QUESTIONS/PURPOSES

We determined (1) changes to the Oswestry Disability Index, (2) frequency of radiographic fusion, (3) complications and reoperations, and (4) the learning curve associated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup.

METHODS

We reviewed our first 124 patients who underwent minimally invasive transforaminal lumbar interbody fusion to treat low-grade spondylolisthesis and degenerative lumbar diseases and did not need a major deformity correction. This represented 63% (124 of 198) of the transforaminal lumbar interbody fusion procedures we performed for those indications during the study period (2003-2007). Eighty-three (67%) patients had complete 5-year followup. Plain radiographs and CT scans were evaluated by two reviewers. Trends of surgical time, blood loss, and hospital stay over time were examined by logarithmic curve fit-regression analysis to evaluate the learning curve.

RESULTS

At 5 years, mean Oswestry Disability Index improved from 60 points preoperatively to 24 points and 79 of 83 patients (95%) had improvement of greater than 10 points. At 5 years, 67 of 83 (81%) achieved radiographic fusion, including 64 of 72 patients (89%) who had single-level surgery. Perioperative complications occurred in 11 of 124 patients (9%), and another surgical procedure was performed in eight of 124 patients (6.5%) involving the index level and seven of 124 patients (5.6%) at adjacent levels. There were slowly decreasing trends of surgical time and hospital stay only in single-level surgery and almost no change in intraoperative blood loss over time, suggesting a challenging learning curve.

CONCLUSIONS

Oswestry Disability Index scores improved for patients with spondylolisthesis and degenerative lumbar diseases treated with minimally invasive transforaminal lumbar interbody fusion at minimum 5-year followup. We suggest this procedure is reasonable for properly selected patients with these indications; however, traditional approaches should still be performed for patients with high-grade spondylolisthesis, patients with a severely collapsed disc space and no motion seen on the dynamic radiographs, patients who need multilevel decompression and arthrodesis, and patients with kyphoscoliosis needing correction.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Clinical and radiographic outcomes of minimally invasive percutaneous pedicle screw placement with intraoperative CT (O-arm) image guidance navigation

Object

Intraoperative CT image–guided navigation (IGN) has been increasingly incorporated into minimally invasive spine surgery (MIS). The vast improvement in image resolution and virtual real-time images with CT-IGN has proven superiority over traditional fluoroscopic techniques. The authors describe their perioperative MIS technique using the O-arm with navigation, and they report their postoperative experience, accuracy results, and technical aspects.

Methods

A retrospective review of 48 consecutive adult patients undergoing minimally invasive percutaneous posterior spinal fusion with intraoperative CT-IGN between July 2010 and August 2013 at Cedars-Sinai Medical Center was performed. Two surgeons assessed 290 screws in a blinded fashion on intraoperative O-arm images and postoperative CT scans for bony pedicle wall breach. Grade 1 breach was defined to be < 2 mm, Grade 2 breach to be between 2 and 4 mm, and a Grade 3 breach to be > 4 mm. Additionally, anterior vertebral body breach was recorded.

Results

Of 290 pedicle screws placed, 280 (96.6%) were in an acceptable position without cortical wall or anterior breach. Of the 10 breaches (3.4%) 5 were lateral (50%), 4 were medial, and 1 was anterior; 90% of breaches were Grade 1–2 and all medial breaches were Grade 1. The one Grade 3 breach was lateral. No vascular or neurological complications were observed intraoperatively, and no significant postoperative complications were noted. The mean clinical follow-up period was 18 months (range 3–39 months). The overall clinical outcomes, measured using the visual analog scale (back pain scores), were improved significantly postoperatively at 3 months compared with preoperatively (visual analog score 6.35 vs 3.57; p < 0.0001). No revision surgery was performed for screw misplacement or neurological deterioration.

Conclusions

New CT-IGN with the mobile O-arm scanner has increased the accuracy of pedicle screw/instrumentation placement using MIS techniques. The authors' high (96.6%) accuracy rate in MIS compares favorably with historical published accuracy rates for fluoroscopy-based techniques. Additional advantages of CT-IGN over fluoroscopic imaging methods are lower occupational radiation exposure for the surgical team, reduced need for postoperative imaging, and decreased rates of revision surgery. For now, the authors simply conclude that use of intraoperative CT-IGN is safe and accurate.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF): surgical technique, long-term 4-year prospective outcomes, and complications compared with an open TLIF cohort

Transforaminal lumbar interbody fusion (TLIF) is an important surgical option for the treatment of back pain and radiculopathy. The minimally invasive TLIF (MI-TLIF) technique is increasingly used to achieve neural element decompression, restoration of segmental alignment and lordosis, and bony fusion. This article reviews the surgical technique, outcomes, and complications in a series of 144 consecutive 1- and 2-level MI-TLIFs in comparison with an institutional control group of 54 open traditional TLIF procedures with a mean of 46 months' follow-up. The evidence base suggests that MI-TLIF can be performed safely with excellent long-term outcomes.

Percutaneous pedicle screw placement in the thoracic spine: A cadaveric study

STUDY DESIGN

A cadaveric study to determine the accuracy of percutaneous screw placement in the thoracic spine using standard fluoroscopic guidance.

SUMMARY OF BACKGROUND DATA

While use of percutaneous pedicle screws in the lumbar spine has increased rapidly, its acceptance in the thoracic spine has been slower. As indications for pedicle screw fixation increase in the thoracic spine so will the need to perform accurate and safe placement of percutaneous screws with or without image navigation. To date, no study has determined the accuracy of percutaneous thoracic pedicle screw placement without use of stereotactic imaging guidance.

MATERIALS AND METHODS

Eighty-six thoracic pedicle screw placements were performed in four cadaveric thoracic spines from T1 to T12. At each level, Ferguson anterior-posterior fluoroscopy was used to localize the pedicle and define the entry point. Screw placement was attempted unless the borders of the pedicle could not be delineated solely using intraoperative fluoroscopic guidance. The cadavers were assessed using pre- and postprocedural computed tomography (CT) scans as well as dissected and visually inspected in order to determine the medial breach rate.

RESULTS

Ninety pedicles were attempted and 86 screws were placed. CT analysis of screw placement accuracy revealed that only one screw (1.2%) breached the medial aspect of the pedicle by more than 2 mm. A total of four screws (4.7%) were found to have breached medially by visual inspection (three Grade 1 and one Grade 2). One (1.2%) lateral breach was greater than 2 mm and no screw violated the neural foramen. The correlation coefficient of pedicle screw violations and pedicle diameter was found to be 0.96.

CONCLUSIONS

This cadaveric study shows that percutaneous pedicle screw placement can be performed in the thoracic spine without a significant increase in the pedicle breach rate as compared with standard open techniques. A small percentage (4.4%) of pedicles, especially high in the thoracic spine, may not be safely visualized.

Comparison of the results of MIS-TLIF and open TLIF techniques in laborers

Objective: To compare clinical outcomes in laborers who have undergone open transforaminal interbody fusion (TLIF) and minimally invasive transforaminal interbody fusion (MIS TLIF). Methods: 78 patients were submitted to lumbar arthrodesis by the same two spine surgeons partners from January 2008 to December 2012. Forty-one were submitted to traditional open arthrodesis and 37 to the minimally invasive procedure. Three patients were not included because they had already retired from work. The analyzed variables were length of hospitalization, length of follow-up, type of access (TILF or MIS TLIF), need for blood transfusion, percentage of improvement or worsening after surgery, pre- and postoperative VAS scale, time off work, pre-and postoperative Oswestry disability index, and general aspects of the laborers such as age, education, profession, working time, amount of daily weight carried at work, and use or not of personal protective equipment. Results: Time off work was longer in the TLIF group (average of 9.84 months) compared with the MIS TLIF group (average of 3.20 months). Significant improvement in postoperative VAS and Oswestry was achieved in both groups. Average length of hospitalization was 5.73 days for the TLIF group and 2.76 days for the MIS TLIF group. Conclusions: Minimally invasive transforaminal lumbar interbody fusion presents similar results when compared to open TLIF, but has the benefits of less postoperative morbidity, shorter hospitalization times, and faster rehabilitation in laborer patients.

Hybrid technique for posterior lumbar interbody fusion: a combination of open decompression and percutaneous pedicle screw fixation

The authors describe a hybrid technique that involves a combination of open decompression and posterior lumbar interbody fusion (PLIF) and percutaneously inserted pedicle screws. This technique allows performance of PLIF and decompression via a midline incision and approach without compromising operative time and visualization. Furthermore, compared to standard open decompression, this approach reduces post-operative wound pain because the small midline incision significantly reduces muscle trauma by obviating the need to dissect the paraspinal muscles off the facet joint complex and by avoiding posterolateral fusion, thus requiring limited lateral muscle dissection off the transverse processes. A series of patients with Grade I-II spondylolisthesis at L4-5 and moderate-severe canal/foraminal stenosis underwent midline PLIF at L4-5, with closure of the midline incision. Percutaneous pedicle screws were inserted, thereby minimizing local muscle trauma, reduction of the spondylolisthesis being performed by using a pedicle screw construct. Rods were inserted percutaneously to link the L4 and L5 pedicle screws. Image intensification was used to confirmed satisfactory screw placement and reduction of spondylolisthesis. The results of a prospective study comparing a standard open decompression and fusion technique for spondylolisthesis versus the minimally invasive hybrid technique are discussed. The minimally invasive technique resulted in shorter hospital stay, earlier mobilization and reduced postoperative narcotic usage. The long-term clinical outcomes were equivalent in the two groups.

Comparison of minimally invasive versus open transforaminal lumbar interbody fusion in two-level degenerative lumbar disease

PURPOSE

The purpose of this study was to compare the clinical and radiological outcomes of minimally invasive versus open transforaminal lumbar interbody fusion in two-level degenerative lumbar disease.

METHODS

We conducted a prospective cohort study of 82 patients, who underwent two-level minimally invasive or open transforaminal lumbar interbody fusion (TLIF) from March 2010 to December 2011. Forty-four patients underwent minimally invasive transforaminal lumbar interbody fusion (MITLIF) (group A) and 38 patients underwent the traditional open TLIF (group B). Demographic data and clinical characteristics were comparable between the two groups before surgery (p > 0.05). Peri-operative data, clinical and radiological outcomes between the two groups were compared.

RESULTS

The mean follow-up period was 20.6 ± 4.5 months for group A and 20.0 ± 3.3 months for group B (p > 0.05). No significant difference existed in operating time between the two group (p > 0.05). X-ray exposure time was significantly longer for MITLIF compared to open cases. Intra-operative blood loss and duration of postoperatively hospital stay of group A were significantly superior to those of group B (p < 0.05). On postoperative day three, MITLIF patients had significantly less pain compared to patients with the open procedure. No statistical difference existed in pre-operative and latest VAS value of back pain (VAS-BP) and leg pain (VAS-LP), pre-operative and latest ODI between the two groups. The fusion rate of the two groups was similar (p < 0.05). Complications included small dural tear, superficial wound infection and overlong screws. When comparing the total complications, no significant difference existed between the groups (p > 0.05).

CONCLUSIONS

MITLIF offers several potential advantages including postoperative back pain and leg pain, intra-operative blood loss, transfusion and duration of hospital stay postoperatively in treating two-level lumbar degenerative disease. However, it required much more radiation exposure.

Evaluation of hip flexion strength following lateral lumbar interbody fusion

BACKGROUND CONTEXT

Lateral interbody fusion (LIF) is a minimally invasive procedure that is designed to achieve a solid interbody fusion while minimizing the damage to the surrounding soft tissue. Although short-term results have been promising, few data have been published to date regarding its risks and complication rate.

PURPOSE

The aim was to evaluate the extent of injury to the psoas muscle after the LIF procedure by measuring hip flexion strength.

STUDY DESIGN

A prospective case series was used in the study.

METHOD

Hip flexion strength was measured using a handheld digital dynamometer while the patient was seated on a chair; the examiner held the device against the patient's attempt to flex the hip. Both sides were measured to compare the operated and nonoperated psoas muscles. Each side was measured three times and the average amount (in pounds) was recorded. Measurements were done before and after surgery on Day 2-3, at 2 weeks, 6 weeks, and at 3 and 6 months.

RESULTS

Thirty-three patients were recruited for this study. Mean preoperative hip flexion strength values were 20.7±3.47 lb and 21.3±4.31 lb for operated and nonoperated legs, respectively, with no significant difference (p=.85). With a mean of 11.2±2.24 lb postoperative measurements on Day 2, the operated side showed statistically significant reduction of strength (p=.0001). The nonoperated side was also weaker postoperatively, but not significantly (mean=19.12±1.74 lb; p=.097). From the first follow-up visit at 2 weeks, the values on the operated leg had returned to baseline values (20.6, p=.97) and were not significantly different from preoperative values on either side.

DISCUSSION

Hip flexion was weakened immediately after the LIF procedure, which may be attributed to psoas muscle injury during the procedure. However, this damage was temporary, with almost complete return to baseline values by 2 weeks.

Anterior dislodgement of a fusion cage after transforaminal lumbar interbody fusion for the treatment of isthmic spondylolisthesis

Transforaminal lumbar interbody fusion (TLIF) is commonly used procedure for spinal fusion. However, there are no reports describing anterior cage dislodgement after surgery. This report is a rare case of anterior dislodgement of fusion cage after TLIF for the treatment of isthmic spondylolisthesis with lumbosacral transitional vertebra (LSTV). A 51-year-old man underwent TLIF at L4-5 with posterior instrumentation for the treatment of grade 1 isthmic spondylolisthesis with LSTV. At 7 weeks postoperatively, imaging studies demonstrated that banana-shaped cage migrated anteriorly and anterolisthesis recurred at the index level with pseudoarthrosis. The cage was removed and exchanged by new cage through anterior approach, and screws were replaced with larger size ones and cement augmentation was added. At postoperative 2 days of revision surgery, computed tomography (CT) showed fracture on lateral pedicle and body wall of L5 vertebra. He underwent surgery again for paraspinal decompression at L4-5 and extension of instrumentation to S1 vertebra. His back and leg pains improved significantly after final revision surgery and symptom relief was maintained during follow-up period. At 6 months follow-up, CT images showed solid fusion at L4-5 level. Careful cage selection for TLIF must be done for treatment of spondylolisthesis accompanied with deformed LSTV, especially when reduction will be attempted. Banana-shaped cage should be positioned anteriorly, but anterior dislodgement of cage and reduction failure may occur in case of a highly unstable spine. Revision surgery for the treatment of an anteriorly dislodged cage may be effectively performed using an anterior approach.

Learning curve and complications of minimally invasive transforaminal lumbar interbody fusion

Object

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has the potential advantage of minimizing soft-tissue damage and reducing recovery time compared to open procedures. A steep learning curve has been described for the technique. The aim of the present study was to define the learning curve that describes the progress of a single surgeon performing the MI-TLIF.

Methods

One hundred fifty consecutive patients with degenerative lumbar disease who underwent 1- or 2-level MI-TLIF were included in the study. Operative time, corrected operative time per level, and complications were analyzed. The learning curve was assessed using a negative exponential curve-fit regression analysis.

Results

One hundred ten patients underwent 1-level and 18 patients underwent 2-level MI-TLIF; the remaining 22 underwent a single-level procedure plus an ancillary procedure (decompression at adjacent level, vertebral augmentation through fenestrated pedicle screws, interspinous device at adjacent level). Negative exponential curves appropriately described the relationship between operative time and experience for 1-level surgery and after correction of operative time per level (R2 = 0.65 and 0.57). The median operative time was 140 minutes (interquartile range 120–173 minutes), and a 50% learning milestone was achieved at Case 12; a 90% learning milestone was achieved at Case 39. No patient required transfusion in the perioperative period. The overall complication rate was 12.67% and the most frequent complication was a dural tear (5.32%). Before the 50% and 90% learning milestones, the complication rates were 33% and 20.51%, respectively.

Conclusions

The MI-TLIF is a reliable and effective option for lumbar arthrodesis. According to the present study, 90% of the learning curve can be achieved at around the 40th case.

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.

Minimally invasive versus open transforaminal lumbar interbody fusion: a meta-analysis based on the current evidence

PURPOSE

This is a meta-analysis of randomized and non-randomized studies comparing the clinical and radiological efficacy of minimally invasive (MI) and conventional open transforaminal lumbar interbody fusion (open-TLIF) for degenerative lumbar diseases.

METHODS

A literature search of the MEDLINE database identified 11 studies that met our inclusion criteria. A total of 785 patients were examined. Pooled estimates of clinical and radiological outcomes, and corresponding 95% confidence intervals were calculated.

RESULTS

The pooled data revealed that MI-TLIF was associated with less blood loss, shorter hospital stay, and a trend of better functional outcomes when compared with open-TLIF. However, MI-TLIF significantly increased the intraoperative X-ray exposure. Both techniques had similar operative time, complication rate, and re-operation rate.

CONCLUSIONS

Based on the available evidence, MI-TLIF for degenerative lumbar diseases might lead to better patient-based outcomes. MI-TLIF would be a promising procedure, but extra efforts are needed to reduce its intraoperative radiation exposure. More randomized controlled trials are needed to compare these two surgical options.

Back muscle changes after pedicle based dynamic stabilization

OBJECTIVE

Many studies have investigated paraspinal muscle changes after posterior lumbar surgery, including lumbar fusion. However, no study has been performed to investigate back muscle changes after pedicle based dynamic stabilization in patients with degenerative lumbar spinal diseases. In this study, the authors compared back muscle cross sectional area (MCSA) changes after non-fusion pedicle based dynamic stabilization.

METHODS

Thirty-two consecutive patients who underwent non-fusion pedicle based dynamic stabilization (PDS) at the L4-L5 level between February 2005 and January 2008 were included in this retrospective study. In addition, 11 patients who underwent traditional lumbar fusion (LF) during the same period were enrolled for comparative purposes. Preoperative and postoperative MCSAs of the paraspinal (multifidus+longissimus), psoas, and multifidus muscles were measured using computed tomographic axial sections taken at the L4 lower vertebral body level, which best visualize the paraspinal and psoas muscles. Measurements were made preoperatively and at more than 6 months after surgery.

RESULTS

Overall, back muscles showed decreases in MCSAs in the PDS and LF groups, and the multifidus was most affected in both groups, but more so in the LF group. The PDS group showed better back muscle preservation than the LF group for all measured muscles. The multifidus MCSA was significantly more preserved when the PDS-paraspinal-Wiltse approach was used.

CONCLUSION

Pedicle based dynamic stabilization shows better preservation of paraspinal muscles than posterior lumbar fusion. Furthermore, the minimally invasive paraspinal Wiltse approach was found to preserve multifidus muscles better than the conventional posterior midline approach in PDS group.

Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations, preventable root causes, and surgical tips and tricks

The approach-related morbidity resulting from iatrogenic erector spinae injury in posterior lumbar surgery has become an increasing concern for spine surgeons. Many studies have explained the injury mechanisms and reported new surgical approaches to prevent this iatrogenic injury from their own point of views, but there is still no systemic information for a thorough understanding of this iatrogenic erector spinae injury that may give spine surgeons practical advices in their individual operations. We consequently reviewed the literature on the anatomy of erector spinae, causes of injury, and relative minimally invasive approaches. We found that the local anatomic structures make the erector spinae vulnerable to injury during posterior lumbar surgery, especially the medial multifidus which is innervated only by the medial branch of the dorsal ramus, with no intersegmental nerve supply as in the other paraspinal muscles, and the injury factors mainly include dissection, retraction, denervation, and immobility. Studies suggest that the goal of prevention is to preserve the physiological structure of erector spinae and to avoid or limit the injury causes: approaches through spatium intermusculare and approaches with endoscope and tubular retractor system can prevent the erector spinae from injury by less dissection and retraction; non-fusion techniques may prevent the erector spinae from disuse atrophy by preserving the segmental motion and the adjacent erector spinae activity.

Perioperative Outcomes and Complications of Pedicle Subtraction Osteotomy in Cases With Single Versus Two Attending Surgeons

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To assess the perioperative morbidity of pedicle subtraction osteotomy (PSO) based on the presence of 1 versus 2 attending surgeons.

BACKGROUND SUMMARY

Pedicle subtraction osteotomies are challenging cases with high complication rates and substantial physiological burden on patients. The literature supports the benefits of 2-surgeon strategies in complex cases in other specialties.

METHODS

We reviewed a single institution database of all pedicle subtraction osteotomies (78 cases) from 2005-2010 and divided the cohort into single versus 2-surgeon groups (42 vs. 36 cases, respectively). We performed subset analysis after excluding cases before 2007 and excluding patients with staged anterior and posterior procedures. We analyzed cases for estimated blood loss, length of surgery, length of stay, radiographic analysis, rate of return to the operating room within 30 days, and medical and neurological complications.

RESULTS

The groups were similar when comparing mean number of posterior levels fused, levels decompressed and revision rates, however, the average age of the single surgeon and 2 surgeon groups was 57.6 and 64.3 years, respectively (p = .02). The 2 groups had comparable correction of radiographic parameters. Mean percent estimated blood loss for single versus 2 surgeons was 109% versus 35% (p < .001) and estimated blood loss was 5,278 versus 2,003 mL (p < .001). Average surgical time for single versus 2 surgeons was 7.6 versus 5.0 hours (p < .001). A total of 45% of single-surgeon patients compared with 25% of 2-surgeon patients experienced at least 1 major complication within 30 days. In the single-surgeon group, 19% had unplanned surgery within 30 days, versus 8% in the 2-surgeon group.

CONCLUSIONS

The use of 2 surgeons at an experienced spine deformity center decreases the operative time and estimated blood loss, and may be a key factor in witnessed decreased major complication prevalence. This approach also may decrease the rate of premature case termination and return to operating room in 30 days.

Long-term Follow-up of Minimal-Access and Open Posterior Lumbar Interbody Fusion for Spondylolisthesis

BACKGROUND:

Although posterior lumbar interbody fusion (PLIF) is regarded as an effective treatment for spondylolisthesis, few studies have reported comprehensive, long-term outcome data, and none has investigated the incidence of deterioration of outcomes.

OBJECTIVE:

To determine and compare the success rates and long-term stability of outcomes of open PLIF and minimal-access PLIF in the treatment of radicular pain and back pain in patients with spondylolisthesis.

METHODS:

Forty-three patients were followed for a minimum of 3 years. They completed a Short-Form Health Survey and visual analog scores for back pain and leg pain and underwent lumbar spine radiography. Outcomes were compared with baseline data and 12-month data.

RESULTS:

Surgery succeeded in reducing listhesis and increasing disc height, but had little effect on lumbar lordosis or the angulation of the segment treated. At 12 months after surgery, listhesis was reduced, disc height was increased, leg pain was reduced or eliminated, and physical functioning restored. Back pain was less often relieved. These outcomes were largely maintained over the ensuing 2 years. Only 5% to 10% of patients reported deterioration in their relief of pain. Depending on the definition adopted for success, the long-term success rate of PLIF may be as high as 70%.

CONCLUSION:

For the relief of leg pain, the success rates of open PLIF (70%) and minimal-access PLIF (67%) for spondylolisthesis are high and durable in the long-term. PLIF is less often successful in relieving back pain, but the outcomes are maintained. The outcomes of open PLIF and minimal-access PLIF were statistically indistinguishable.

Minimally invasive management of thoraco-lumbar fractures: combined percutaneous fixation and balloon kyphoplasty

STUDY DESIGN

Retrospective review of prospectively collected data.

BACKGROUND

There is no consensus regarding the ideal treatment of thoraco-lumbar spine fractures without neurological compromise. Many surgical techniques have been described but none has proved its definite superiority. The main drawback of these procedures is directly related to the morbidity of the approach. As minimally invasive fixation combined with balloon kyphoplasty for treatment of thoraco-lumbar fractures is gaining popularity, its efficacy has yet to be established.

PURPOSE

The purpose of this study is to report operative data, clinical and radiological outcomes of patients undergoing minimally invasive management of thoraco-lumbar fracture at our institutions.

METHODS

Forty-one patients underwent percutaneous kyphoplasty and stabilization for treatment of single-level fracture of the thoracic or lumbar spine. All patients were neurologically intact. There were 20 males and 21 females with an average age of 50 years.

RESULTS

The mean follow-up was 15 months (3-90 months). The mean operative time was 102 minutes (range 35-240 minutes) and the mean blood loss was <100mL. VAS was significantly improved from 6.7 to 0.7 at last follow-up. Vertebral kyphosis decreased by 16° to 7.8° postoperatively (P<0.001). Local kyphosis and percentage of collapse were also significantly improved from 8° to 5.6° and from 35% to 16% at last follow-up. Fifteen leaks have been identified, three of which were posterior; all remained asymptomatic. No patient worsened his or her neurological condition postoperatively.

CONCLUSION

Percutaneous stabilization plus balloon kyphoplasty seems to be a safe and effective technique to manage thoraco-lumbar fractures without neurological impairment.

Minimally invasive transforaminal lumbar interbody fusion: a perspective on current evidence and clinical knowledge

This paper reviews the current published data regarding open transforaminal lumbar interbody fusion (TLIF) in relation to minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). Introduction. MI-TLIF, a modern method for lumbar interbody arthrodesis, has allowed for a minimally invasive method to treat degenerative spinal pathologies. Currently, there is limited literature that compares TLIF directly to MI-TLIF. Thus, we seek to discuss the current literature on these techniques. Methods. Using a PubMed search, we reviewed recent publications of open and MI-TLIF, dating from 2002 to 2012. We discussed these studies and their findings in this paper, focusing on patient-reported outcomes as well as complications. Results. Data found in 14 articles of the literature was analyzed. Using these reports, we found mean follow-up was 20 months. The mean patient study size was 52. Seven of the articles directly compared outcomes of open TLIF with MI-TLIF, such as mean duration of surgery, length of post-operative stay, blood loss, and complications. Conclusion. Although high-class data comparing these two techniques is lacking, the current evidence supports MI-TLIF with outcomes comparable to that of the traditional, open technique. Further prospective, randomized studies will help to further our understanding of this minimally invasive technique.

The microendoscopic decompression of lumbar stenosis: a review of the current literature and clinical results

Lumbar stenosis is a well-defined pathologic condition with excellent surgical outcomes. Empiric evidence as well as randomized, prospective trials has demonstrated the superior efficacy of surgery compared to medical management for lumbar stenosis. Traditionally, lumbar stenosis is decompressed with open laminectomies. This involves removal of the spinous process, lamina, and the posterior musculoligamentous complex (posterior tension band). This approach provides excellent improvement in symptoms, but is also associated with potential postoperative spinal instability. This may result in subsequent need for spinal fusion. Advances in technology have enabled the application of minimally invasive spine surgery (MISS) as an acceptable alternative to open lumbar decompression. Recent studies have shown similar to improved perioperative outcomes when comparing MISS to open decompression for lumbar stenosis. A literature review of MISS for decompression of lumbar stenosis with tubular retractors was performed to evaluate the outcomes of this modern surgical technique. In addition, a discussion of the advantages and limitations of this technique is provided.

Paradigm changes in spine surgery: evolution of minimally invasive techniques

Minimally invasive spine surgery (MISS) techniques were developed to address morbidities associated with open spinal surgery approaches. MISS was initially applied for indications such as the microendoscopic decompression of stenosis (MEDS)-an operation that has become widely implemented in modern spine surgery practice. Minimally invasive surgery for MEDS is an excellent example of how an MISS technique has improved outcomes compared with the use of traditional open surgical procedures. In parallel with reports of surgeon experience, accumulating clinical evidence suggests that MISS is favoured over open surgery, and one could argue that the role of MISS techniques will continue to expand. As the field of minimally invasive surgery has developed, MISS has been implemented for the treatment of increasingly difficult and complex pathologies, including trauma, spinal malignancies and spinal deformity in adults. In this Review, we present the accumulating evidence in support of minimally invasive techniques for established MISS indications, such as lumbar stenosis, and discuss the need for additional level I and level II data to demonstrate the benefit of MISS over traditional open surgery. The expanding utility of MISS techniques to address an increasingly broad range of spinal pathologies is also highlighted.

A prospective randomized controlled study comparing transforaminal lumbar interbody fusion techniques for degenerative spondylolisthesis: unilateral pedicle screw and 1 cage versus bilateral pedicle screws and 2 cages

OBJECT

Many surgeons currently prefer to use transforaminal lumbar interbody fusion (TLIF), placing 1 unilateral pedicle screw (PS) and 1 cage. However, no study has examined whether unilateral fixation improves surgical outcome. The authors conducted a prospective randomized controlled trial with a minimum 2-year follow-up to analyze TLIF outcomes for 2 techniques: placement of a unilateral PS and a cage compared with placement of bilateral PSs and 2 cages.

METHODS

Fifty patients with degenerative spondylolisthesis undergoing single-level TLIF were randomly assigned to receive either unilateral or bilateral fixation. Parameters compared between the groups were surgical invasiveness, severity of intermittent claudication, pre- and postoperative visual analog scale (VAS) scores (from 0 to 10 for back pain, lower-extremity pain, and lower-extremity numbness), postoperative disability scores for lumbar spinal disorders (Japanese Orthopaedic Association Back Pain Evaluation Questionnaire [JOABPEQ]), and fusion rates.

RESULTS

The mean operative time for TLIF was significantly (p = 0.05) shorter and mean estimated blood loss was significantly lower in the unilateral than in the bilateral group. Intermittent claudication improved in response to each technique, but there was no significant intergroup difference. The unilateral group had a nonsignificant tendency toward less improvement in VAS score for back pain (1.5 vs 3.7 for the bilateral group) and exhibited significantly less improvement in VAS score for lower-extremity pain (2.1 vs 5.1, respectively) and numbness (1.7 vs 4.4). There were no significant differences between the groups in postsurgical scores for all 5 items of the JOABPEQ. The fusion rates were 87.5% (21 of 24 patients) in the unilateral group and 95.7% (22 of 23) in the bilateral group.

CONCLUSIONS

Transforaminal lumbar interbody fusion involving unilateral PS fixation and a single-cage technique is less invasive than a 2-cage technique and bilateral fixation, and it improved patients' symptoms. However, it resulted in less improvement in back pain, lower-extremity pain, and lower-extremity numbness. When considering unilateral PS fixation and a single cage, the surgeon should be aware of the potential limitations of this technique. Clinical trial registration no.: UMIN000007833 (UMIN).

Minimally invasive surgery compared to open spinal fusion for the treatment of degenerative lumbar spine pathologies

This clinical study prospectively compares the results of open surgery to minimally invasive fusion for degenerative lumbar spine pathologies. Eighty-two patients were studied (41 minimally invasive surgery [MIS] spinal fusion, 41 open surgical equivalent) under a single surgeon (R. J. Mobbs). The two groups were compared using the Oswestry Disability Index, the Short Form-12 version 1, the Visual Analogue Scale score, the Patient Satisfaction Index, length of hospital stay, time to mobilise, postoperative medication and complications. The MIS cohort was found to have significantly less postoperative pain, and to have met the expectations of a significantly greater proportion of patients than conventional open surgery. The patients who underwent the MIS approach also had significantly shorter length of stay, time to mobilisation, lower opioid use and total complication rates. In our study MIS provided similar efficacy to the conventional open technique, and proved to be superior with regard to patient satisfaction, length of hospital stay, time to mobilise and complication rates.

Mid-term clinical results of minimally invasive decompression and posterolateral fusion with percutaneous pedicle screws versus conventional approach for degenerative spondylolisthesis with spinal stenosis

INTRODUCTION

In order to minimize perioperative invasiveness and improve the patients' functional capacity of daily living, we have performed minimally invasive lumbar decompression and posterolateral fusion (MIS-PLF) with percutaneous pedicle screw fixation for degenerative spondylolisthesis with spinal stenosis. Although several minimally invasive fusion procedures have been reported, no study has yet demonstrated the efficacy of MIS-PLF in degenerative spondylolisthesis of the lumbar spine. This study prospectively compared the mid-term clinical outcome of MIS-PLF with those of conventional PLF (open-PLF) focusing on perioperative invasiveness and patients' functional capacity of daily living.

MATERIALS AND METHODS

A total of 80 patients received single-level PLF for lumbar degenerative spondylolisthesis with spinal stenosis. There were 43 cases of MIS-PLF and 37 cases of open-PLF. The surgical technique of MIS-PLF included making a main incision (4 cm), and neural decompression followed by percutaneous pedicle screwing and rod insertion. The posterolateral gutter including the medial transverse process was decorticated and iliac bone graft was performed. The parameters analyzed up to a 2-year period included the operation time, intra and postoperative blood loss, Oswestry-Disability Index (ODI), Roland-Morris Questionnaire (RMQ), the Japanese Orthopaedic Association score, and the visual analogue scale of low back pain. The fusion rate and complications were also reviewed.

RESULTS

The average operation time was statistically equivalent between the two groups. The intraoperative blood loss was significantly less in the MIS-PLF group (181 ml) when compared to the open-PLF group (453 ml). The postoperative bleeding on day 1 was also less in the MIS-PLF group (210 ml) when compared to the open-PLF group (406 ml). The ODI and RMQ scores rapidly decreased during the initial postoperative 2 weeks in the MIS-PLF group, and consistently maintained lower values than those in the open-PLF group at 3, 6, 12, and 24 months postoperatively. The fusion rate was statistically equivalent between the two groups (98 vs. 100%), and no major complications occurred.

CONCLUSION

The MIS-PLF utilizing a percutaneous pedicle screw system is less invasive compared to conventional open-PLF. The reduction in postoperative pain led to an increase in activity of daily living (ADL), demonstrating rapid improvement of several functional parameters. This superiority in the MIS-PLF group was maintained until 2 years postoperatively, suggesting that less invasive PLF offers better mid-term results in terms of reducing low back pain and improving patients' functional capacity of daily living. The MIS-PLF utilizing percutaneous pedicle screw fixation serves as an alternative technique, eliminating the need for conventional open approach.

Surgical outcomes of minimally invasive transforaminal lumbar interbody fusion for the treatment of spondylolisthesis and degenerative segmental instability

Study Design

This is a retrospective case study.

Purpose

This study was designed to analyze the surgical outcomes of patients who underwent minimally invasive transforaminal lumbar interbody fusion (TLIF) for the treatment of spondylolisthesis and degenerative segmental instability.

Overview of Literature

If the surgical outcomes of a procedure are evaluated together with multiple indications, it is not clear how the procedure helped each subgroup of patients. For the reason that some indications achieve better outcomes than the others, we performed a subgroup analysis using validated outcome measures to demonstrate the optimal indications and the treatment results of TLIF.

Methods

We conducted subgroup analyses by comparing the prospectively collecting data from the consecutive patients who underwent single-level minimally invasive TLIF for the treatment of the following 3 subgroups of indications: 23 cases of low-grade spondylolytic spondylolisthesis, 24 cases of degenerative spondylolisthesis, and 19 cases of degenerative segmental instability.

Results

The average duration of follow up was 36.1 ± 9.9 months (range, 24 to 63 months). The preoperative pain and disability scores were significantly improved at final postoperative follow-up in all the subgroups (all measurements: p < 0.0001). The 3 subgroups exhibited an equivalent improvement of the pain and disability scores at the final follow-up. The rates of radiographic solid fusion and complications were also similar among the 3 groups.

Conclusions

Our data suggests that minimally invasive TLIF optimally and equivalently alleviates all of the associated symptoms and disabilities from low-grade spondylolisthesis and degenerative segmental instability. Furthermore, these patients seem to have optimal surgical indications for minimally invasive TLIF, while maintaining favorable surgical outcomes.

Percutaneous placement of pedicle screws in overweight and obese patients

BACKGROUND CONTEXT

In obese patients, placing pedicle screws percutaneously is a particular challenge. As the bulky and thick configuration of obese patients may produce fuzzier fluoroscopic view and longer passage of surgical instruments, the chances of misplacement might increase.

PURPOSE

This study was designed to evaluate the effect of patient's body habitus on the incidence of percutaneous pedicle screw misplacements.

STUDY DESIGN/SETTING

A retrospective study with prospectively collecting data.

PATIENT SAMPLE

Three hundred seventy percutaneous pedicle screws for minimally invasive lumbar spinal fusion surgery were noted in 89 consecutive patients.

OUTCOME MEASURES

The position and direction of screws to pedicle were evaluated using the findings in computed tomography (CT) scan with the following grading method: Grade A, completely in the range without pedicle cortex violation; Grade B, pedicle wall violation <2 mm; Grade C, pedicle wall violation 2 to 4 mm; and Grade D, pedicle wall violation >4 mm. The direction of violation was grouped as medial, lateral, cranial, and caudal.

METHODS

Two independent observers retrospectively examined all of the postoperative CT images. All screws were assigned into one of the following three groups along with patient's body mass index (BMI): 157 screws (38 patients) in normal weight (BMI<25) group; 124 (29) in overweight (25≤BMI<30) group; and 89 (22) in obese (BMI≥30) group. A pedicle screw was considered misplaced if the grade was defined as B, C, and D. Multivariate logistic regression analyses were performed to evaluate the association between screw misplacements and BMI.

RESULTS

Sixty-two screws (16.8%) were misplaced with the majority of Grade B (72.6%, 45/62) and lateral direction (72.6%, 45/62). Twenty-eight screws (22.6%, 28/124) were misplaced in overweight group, 12 (13.5%, 12/89) in obese group, and 22 (14.0%, 22/157) in normal weight group. Two symptomatic pedicle violations were noted with Grade D: a caudal violation was found in overweight group, which happened in the third case of surgeon's series; a medial misplacement, which was occurred in the 29th case, was noticed in obese group. There was no statistically significant association of pedicle violations along with patient's BMI (odds ratio [OR]=1.00, 95% confidence interval [CI]=0.94-1.07, p=.99). Moreover, no other factors, such as patient's age, gender, preoperative diagnosis, number of the fused segments, and year of the surgery, had a statistically significant relationship with pedicle violations. On the contrary, pedicle violations observed approximately five times more frequently at the level of L3 (47.1%, 8/17) and L4 (28.8%, 36/125) rather than L5 (10.1%, 16/158) and S1 (2.9%, 2/70) (OR=4.95, 95% CI=2.62-9.33, p<.0001).

CONCLUSIONS

Although symptomatic pedicle violations were noted in the earlier period of surgeon's learning curve and in overweight and obese patients, no statistical evidence could be found between patient's body habitus and percutaneous pedicle screw misplacement. Our data also suggest that greater caution should be exercised to avoid pedicle violations especially at L3 and L4.

Anterior discectomy and total disc replacement for three patients with multiple recurrent lumbar disc herniations

BACKGROUND CONTEXT

Although results of primary discectomy are generally excellent with relief of leg pain, recurrent lumbar disc herniation is relatively common ranging from 5% to 25%. Patients with recurrent herniation may undergo revision surgery; however, this carries with it increased risks and lower success rates. Many surgeons will advocate a fusion in addition to repeat discectomy after the third recurrent herniated disc. With the approval of lumbar total disc arthroplasty, there now exists another option for the patient with three or more recurrent disc herniations to preserve motion, theoretically decrease the rate of adjacent-level disease, and ameliorate the patient's symptoms.

PURPOSE

The purpose of this case report is to describe our experience using total disc replacement (TDR) in three patients after prior partial hemilaminectomy and discectomy for the treatment of a third and fourth recurrent lumbar disc herniation.

STUDY DESIGN

This article is a report of three cases from a spine specialty center describing an alternative surgical technique for patients with multiple recurrent lumbar disc herniation.

METHODS

Comprehensive chart review of three patients with recurrent lumbar herniation who underwent TDR.

RESULTS

Anterior discectomy and TDR were undertaken, and at most recent follow-up (8-12 months), all patients had improvement of their visual analog scale and Oswestry Disability Index. No patient had postoperative complications or reoperation.

CONCLUSIONS

Recurrent disc herniation is a relatively common problem that may be difficult to treat. Traditionally, a patient presenting with three or more recurrent disc herniation may likely have undergone revision discectomy with fusion. The current case report suggests that TDR may be an alternative option in select patients.

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

Study Design

This is a retrospective study that was done according to clinical and radiological evaluation.

Purpose

We analyzed the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody single level fusion.

Overview of Literature

Minimally invasive transforaminal lumbar interbody fusion is effective surgical method for treating degenerative lumbar disease.

Methods

The study was conducted on 56 patients who were available for longer than 2 years (range, 24 to 45 months) follow-up after undergoing minimally invasive transforminal lumbar interbody single level fusion. Clinical evaluation was performed by the analysis of the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) and the Kirkaldy-Willis score. For the radiological evaluation, the disc space height, the segmental lumbar lordotic angle and the whole lumbar lordotic angle were analyzed. At the final follow-up after operation, the fusion rate was analyzed according to Bridwell's anterior fusion grade.

Results

For the evaluation of clinical outcomes, the VAS score was reduced from an average of 6.7 prior to surgery to an average of 1.8 at the final follow-up. The ODI was decreased from an average of 36.5 prior to surgery to an average of 12.8 at the final follow-up. In regard to the clinical outcomes evaluated by the Kirkaldy-Willis score, better than good results were obtained in 52 cases (92.9%). For the radiological evaluation, the disc space height (p = 0.002), and the whole lumbar lordotic angle (p = 0.001) were increased at the final follow-up. At the final follow-up, regarding the interbody fusion, radiological union was obtained in 54 cases (95.4%).

Conclusions

We think that if surgeons become familiar with the surgical techniques, this is a useful method for minimally invasive spinal surgery.

A minimally invasive posterior lumbar interbody fusion for degenerative lumbar spine instabilities

Percutaneous techniques may be helpful to reduce approach-related morbidity of conventional open surgery. The aim of the study was to evaluate the feasibility and safety of mini-open posterior lumbar interbody fusion for instabilities and degenerative disc diseases. From May 2005 until October 2008, 20 patients affected by monosegmental instability and disc herniation underwent mini-open lumbar interbody fusion combined with percutaneous pedicle screw fixation of the lumbar spine. Clinical outcome was assessed using the Visual Analog Scale, Oswestry Disability Index, and Short Form Health Survey-36. The mean follow-up was 24 months. The mean estimated blood loss was 126 ml; the mean length of stay was 5.3 days; the mean operative time was 171 min. At 24-month follow-up, the mean VAS score was 2.1, mean ODI was 27.1%, and mean SF-36 was 85.2%. 80 screws were implanted in 20 patients. 74 screws showed very good position, 5 screws acceptable, and 1 screw unacceptable. A solid fusion was achieved in 17 patients (85%). In our opinion, mini-open TLIF is a valid and safe treatment of lumbar instability and degenerative disc diseases in order to obtain faster return to daily activities.

Technique, challenges and indications for percutaneous pedicle screw fixation

Minimally invasive techniques in spinal surgery are increasing in popularity due to numerous potential advantages, including reduced length of stay, blood loss and requirements for post-operative analgesia as well as earlier return to work. This review discusses guidelines for safe implantation of percutaneous pedicle screws using an image intensifier technique. As indications for percutaneous pedicle screw techniques expand, the nuances of the minimally invasive surgery technique will also expand. It is paramount that experienced surgeons share their collective knowledge to assist surgeons at their early attempts of these complex, and potentially dangerous, procedures. Technical challenges of percutaneous pedicle screw fixation techniques are also discussed including: small pedicle cannulation, percutaneous rod insertion for multilevel constructs, incision selection for multilevel constructs, changing direction with percutaneous pedicle screw placement, L5/S1 screw head proximity and sclerotic pedicles with difficult Jamshidi placement. We discuss potential indications for minimally invasive fusion techniques for complex spinal surgery and support these with descriptions of illustrative patients.

[Minimally invasive anterior approaches to the lumbosacral junction]

OBJECTIVE

Minimally invasive anterior preparation of the lumbosacral junction L5/S1 via a retro- or transperitoneal approach, possibility of intervertebral mono- or bisegmental rigid (cage, bone graft) or dynamic (disc arthroplasty) segmental stabilization.

INDICATIONS

Degenerative disc disease (DDD) with or without disc herniation. DDD with translatoric or frontal instability. Degenerative or isthmic spondylolisthesis. Adjacent segment degeneration post fusionem. Failed back surgery syndrome (post discectomy, non-union). Spinal stenosis with dynamic segmental instability. Spondylitis/spondylodiscitis.

CONTRAINDICATIONS

Previous transperitoneal lumbar fusion surgery. Adipositas permagna. Relative: Previous abdominal or gynaecological surgery. Aorta bifurcation and/or venous confluens directly in front of the lumbosacral disc space. Inflammation with large prevertebral granulation tissue formation or psoas abscess. Diseases of the gastrointestinal tract.

SURGICAL TECHNIQUE

Anterior horizontal or vertical midline incision over L5/S1. Retroperitoneal or transperitoneal approach via the left or right lower abdomen. Retroperitoneal technique: medialization of the peritoneal sack towards the contralateral side. Transperitoneal technique: mini laparatomy, dissection of the visceral and parietal peritoneum and mobilization of the bowels laterally. Preparation of the anterolateral circumference of the L5/S1 disc space and mobilization of the vessels laterally. Discectomy and preparation of graft bed.

POSTOPERATIVE MANAGEMENT

Functional postoperative care with mobilisation without external support following total lumbar disc replacement; stable trunk brace for 12 weeks in the case of fusion surgeries; no restrictions for standing, walking or sitting.

RESULTS

Between January 2002 and December 2007, 454 patients (248 female, 206 male, average age 47.3 years, range between 15.4 years and 80.0 years,) underwent anterior surgery in the lumbosacral segment using a minimally invasive anterior approach. The spectrum of indications included monosegmental disc degeneration, spinal stenosis with segmental instability, isthmic oder degenerative spondylolisthesis, spondylodiscitis and others. Dynamic segmental support using total lumbar disc replacement was performed in 251 cases. Rigid stabilization with combined posterior internal fixation and anterior interbody fusion was performed in 203 cases (alternatively cage, tricortical iliac crest bone graft, bone substitutes such as hydroxyapatite or bone morphogenetic protein [BMP]). Approach-related, vascular complications occurred in 0.5 % (mainly left common iliac vein). Injuries of the gastrointestinal tract or urogenital tract (kidney, ureter, bladder) did not occur and there were no infections.

Cranial facet joint violations by percutaneously placed pedicle screws adjacent to a minimally invasive lumbar spinal fusion

BACKGROUND CONTEXT

Protecting cranial facet joint is a modifiable risk factor that may decrease the incidence of adjacent segment disease after lumbar spinal fusion. Percutaneously instrumented screws may more frequently violate cranial facet joints because of the potential limitation of screw entry site selection. To our knowledge, however, there is no study that has evaluated the cranial facet joint violations adjacent to minimally invasive lumbar fusion related to percutaneously placed pedicle screws.

PURPOSE

We investigated the incidence and relating factors of cranial facet joint violations by percutaneous pedicle screws.

STUDY DESIGN/SETTING

A retrospective study of prospectively collecting data.

PATIENT SAMPLE

The sample comprises 184 pedicle screws percutaneously placed at the cranial fusion segments in 92 patients who underwent minimally invasive lumbar spinal fusion.

OUTCOME MEASURES

The facet joint violations adjacent to a cranial fusion segment were examined on the postoperative computed tomography (CT) scans.

METHODS

Two independent observers retrospectively examined all the postoperative CT images. A facet joint was considered violated if any of the following situations were encountered: pedicle screw clearly within the facet joint; pedicle screw head clearly within the facet joint; and pedicle screw and/or screw head within 1 mm from or abutting the facet joint, without clear joint involvement.

RESULTS

The incidence of the violations was 50% (46/92) of all patients and 31.5% (58/184) of all screws, which were significantly higher than the previously reported rates with the traditional open procedure (50% vs. 23.5% of all patients, p<.001; 31.5% vs. 15.2% of all screws, p<.001). The violations occurred approximately 3.3 times more frequently at the most cranial pedicle screws of L5 pedicle than at the other pedicles (70.8% vs. 42.6%, odds ratio [OR]=3.3, p=.021). Logistic regression analysis revealed a significant trend toward reducing the incidence of the violations as increasing the year of surgery (OR=0.7, p=.008). The incidence showed no significant relationships with patients' age, gender, body mass index, preoperative diagnosis, the number of fused segments, or the side of screw placement.

CONCLUSIONS

Our data raise a concern about the higher incidence of cranial facet joint violations by percutaneously placed pedicle screws than that previously reported rates by traditionally instrumented screws. Furthermore, more care should be taken to avoid cranial facet joint violations when the surgeon is a novice to percutaneous pedicle screw placement and/or minimally invasive fusion surgery is considered at the L5-S1 segment.

Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system

Background

Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement.

Methods

Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group.

Results

Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques.

Conclusions

Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

Perioperative morbidity and complications in minimal access surgery techniques in obese patients with degenerative lumbar disease

The medical profession is increasingly confronted with the epidemic phenomenon of obesity. Its impact on spine surgery is not quite clear. Published data concerning the use of minimally invasive surgery (MIS) in the spine among obese patients is scarce. The purpose of the present retrospective study was to evaluate perioperative as well as postoperative complication rates in MIS fusion of the lumbar spine in obese, overweight and normal patients classified according to their body mass index. Lumbar MIS fusion was performed by means of TLIF procedures and/or posterolateral fusion alone. A laminotomy was performed in patients with spinal stenosis. Of 72 patients, 39 underwent additional laminotomy for spinal stenosis. No differences were registered in respect of the numbers of fused segments or cages. Any harmful event occurring peri- or postoperatively was noted and included in the statistical analysis. No infection at the site of surgery or severe wound healing disorder was encountered. We registered no difference in blood loss, drainage, or the length of the hospital stay between the three BMI groups. We also observed no difference in complication rates between the three groups. This study confirms the low soft tissue damage of minimal access surgery techniques, which is an important type of surgery in obese patients. The smaller approach helps to minimize infections and wound healing disorders. Moreover, deeper regions of wounds are clearly visualized with the aid of tubular retractors.

Posterior interbody fusion using a diagonal cage with unilateral transpedicular screw fixation for lumbar stenosis

Few reports have described the combined use of unilateral pedicle screw fixation and interbody fusion for lumbar stenosis. We retrospectively reviewed 79 patients with lumbar stenosis. The rationale and effectiveness of unilateral pedicle screw fixation were studied from biomechanical and clinical perspectives, aiming to reduce stiffness of the implant. All patients were operated with posterior interbody fusion using a diagonal cage in combination with unilateral transpedicular screw fixation and had reached the 3-year follow-up interval after operation. The mean operating time was 115 minutes (range=95-150 min) and the mean estimated blood loss was 150 mL (range=100-200 mL). The mean duration of hospital stay was 10 days (range=7-15 days). Clinical outcomes were assessed prior to surgery and reassessed at intervals using Denis' pain and work scales. Fusion status was determined from X-rays and CT scans. At the final follow-up, the clinical results were satisfactory and patients showed significantly improved scores (p<0.01) either on the pain or the work scale. Successful fusion was achieved in all patients. There were no new postoperative radiculopathies, or instances of malpositioned or fractured hardware. Posterior interbody fusion using a diagonal cage with unilateral transpedicular fixation is an effective treatment for decompressive surgery for lumbar stenosis.

Artrodese lombar minimamente invasiva com acesso intermuscular sem material cirúrgico especial: estudo de série de casos

OBJETIVOS: Analisar os resultados clínicos de uma série de pacientes com doença degenerativa da coluna lombar tratados com artrodese circunferencial com acesso minimamente invasivo intermuscular sem material cirúrgico especial. MÉTODOS: Análise de uma série prospectiva de 12 pacientes consecutivos não-randomizados submetidos à fusão lombossacra de 1 nível para doença degenerativa. Avaliados os Índices de Oswestry 2.0 e a escala visual analógica de dor (VAS) no pré-operatório e seis meses após a cirurgia. A artrodese foi realizada por acesso paramediano bilateral entre os músculos multifidus e longissimus com o uso de afastador cervical simples com lâminas cambiáveis e implantes convencionais. RESULTADOS: Houve uma melhora média de 3,6 pontos na VAS e 27,5 pontos percentuais no Índice de Oswestry quando comparadas as avaliações pré-operatórias e após seis meses de follow-up. As melhoras mais marcadas foram nos pacientes que apresentavam ciatalgia por hérnia discal associada à discopatia. Os quesitos do Índice de Oswestry que apresentaram melhor resultado foram a intensidade da dor e a qualidade do sono. Os que apresentaram pior resultado foram a capacidade de levantamento de pesos e a dor ao sentar. Não houve dificuldade adicional devido à técnica e ao material utilizado. CONCLUSÕES: A artrodese da coluna lombossacra por abordagem minimamente invasiva transmuscular pode ser realizada com afastadores cirúrgicos normais e implantes semelhantes ao da técnica tradicional sem prejuízo técnico ou no resultado clínico.

Anatomia do plano intermuscular lombar entre os músculos multífidus e longuíssimo e planejamento pré-operatório com imagens de ressonância nuclear magnética para artrodeses lombares minimamente invasivas

OBJETIVO: Revisar a anatomia da musculatura lombar posterior, demonstrá-la no plano axial da ressonância magnética e medir a distância da linha média até o plano intermuscular entre os músculos multífidus e longuíssimo nos níveis L3/L4, L4/L5 e L5/S1. MÉTODOS: Através do programa OSIRIX para Mac foram realizadas medidas em 50 pacientes adultos, 25 homens e 25 mulheres. Mensuramos a distância bilateralmente nos níveis lombares inferiores. RESULTADOS: A distância média foi de 2,42 cm em L3/L4, de 3,13 cm em L4/L5 e de 3,77 cm em L5/S1, quando não separamos os sexos. Houve um aumento da distância média no sentido craniocaudal nos níveis lombares inferiores e quando comparamos os sexos não houve diferença estatisticamente significativa nos níveis L4/L5 e L5/S1. CONCLUSÃO: Concluímos que o exame de ressonância magnética permite mensurar a distância da linha média até o plano intermuscular entre o multífidus e o longuíssimo e consideramos importante para o planejamento pré-operatório dos procedimentos minimamente invasivos.