Spondylolisthesis

Approach-Related Complications of Anterior Lumbar Interbody Fusion: Results of a Combined Spine and Vascular Surgical Team

Study Design Retrospective analysis of prospectively collected cohort data. Objective Anterior lumbar interbody fusion (ALIF) is a commonly performed procedure for the treatment of degenerative diseases of the lumbar spine. Detailed and comprehensive descriptions of intra- and postoperative complications of ALIF are surprisingly limited in the literature. In this report, we describe our experience with a team model for ALIF and report all complications occurring in our patient series. Methods Patients were prospectively enrolled between January 2009 and January 2013 by a combined spine surgeon and vascular surgeon team. All patients underwent an open ALIF using an anterior approach to the lumbosacral spine. Results From the 227 ALIF cases, mean operative blood loss was 103 mL, ranging from 30 to 900 mL. Mean operative time was 78 minutes. The average length of stay was 5.2 days. Intraoperative vascular injury requiring primary repair with suturing occurred in 15 patients (6.6%). There were 2 cases of postoperative retroperitoneal hematoma. Three patients (1.3%) had incisional hernia requiring revision surgery; 7 (3.1%) patients had prolonged ileus (>7 days) managed conservatively. Four patients described retrograde ejaculation. Sympathetic dysfunction occurred in 15 (6.6%) patients. There were 5 (2.2%) cases of superficial wound infection treated with oral antibiotics, with no deep wound infections requiring reoperation or intravenous therapy. There were no mortalities in this series. Conclusions ALIF is a safe procedure when performed by a combined vascular surgeon and spine surgeon team with acceptably low complication rates. Our series confirms that the team approach results in short operative times and length of stay, with rapid control of intraoperative vessel injury and low overall blood loss.

Retroperitoneal oblique corridor to the L2-S1 intervertebral discs: an MRI study

OBJECT The purpose of this study was to analyze MR images of the lumbar spine and document: 1) the oblique corridor at each lumbar disc level between the psoas muscle and the great vessels, and 2) oblique access to the L5-S1 disc space. Access to the lumbar spine without disruption of the psoas muscle could translate into decreased frequency of postoperative neurological complications observed after a transpsoas approach. The authors investigated the retroperitoneal oblique corridor of L2-S1 as a means of surgical access to the intervertebral discs. This oblique approach avoids the psoas muscle and is a safe and potentially superior alternative to the lateral transpsoas approach used by many surgeons. METHODS One hundred thirty-three MRI studies performed between May 4, 2012, and February 27, 2013, were randomly selected from the authors' database. Thirty-three MR images were excluded due to technical issues or altered lumbar anatomy due to previous spine surgery. The oblique corridor was defined as the distance between the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5-S1 oblique corridor was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel (axial view) and vertically to the first vascular structure that crossed midline (sagittal view). RESULTS The oblique corridor measurements to the L2-5 discs have the following mean distances: L2-3 = 16.04 mm, L3-4 = 14.21 mm, and L4-5 = 10.28 mm. The L5-S1 corridor mean distance was 10 mm between midline and left common iliac vessel, and 10.13 mm from the first midline vessel to the inferior endplate of L-5. The bifurcation of the aorta and confluence of the vena cava were also analyzed in this study. The aortic bifurcation was found at the L-3 vertebral body in 2% of the MR images, at the L3-4 disc in 5%, at the L-4 vertebral body in 43%, at the L4-5 disc in 11%, and at the L-5 vertebral body in 9%. The confluence of the iliac veins was found at lower levels: 45% at the L-4 level, 19.39% at the L4-5 intervertebral disc, and 34% at the L-5 vertebral body. CONCLUSIONS An oblique corridor of access to the L2-5 discs was found in 90% of the MR images (99% access to L2-3, 100% access to L3-4, and 91% access to L4-5). Access to the L5-S1 disc was also established in 69% of the MR images analyzed. The lower the confluence of iliac veins, the less probable it was that access to the L5-S1 intervertebral disc space was observed. These findings support the use of lumbar MRI as a tool to predetermine the presence of an oblique corridor for access to the L2-S1 intervertebral disc spaces prior to lumbar spine surgery.

Anterior lumbar interbody fusion with integrated fixation and adjunctive posterior stabilization: A comparative biomechanical analysis

BACKGROUND

Interbody fusion cages with integrated fixation components have become of interest due to their ability to provide enhanced post-operative stability and mitigate device migration. A recently approved anterior lumbar interbody fusion cage with integrated fixation anchors has yet to be compared in vitro to a standard polyetheretherketone cage when used in combination with an interspinous process clamp.

METHODS

Twelve human cadaveric lumbar segments were implanted at L4-L5 with a Solus interbody cage (n=6) or standard polyetheretherketone cage (n=6) following Intact testing and discectomy. Each cage was subsequently evaluated in all primary modes of loading after supplementation with the following posterior constructs: interspinous process clamp, bilateral transfacet screws, unilateral transfacet screw with contralateral pedicle screws, and bilateral pedicle screws. Range of motion results were normalized to Intact, and a two-way mixed analysis of variance was utilized to detect statistical differences.

FINDINGS

The Solus cage in combination with all posterior constructs provided significant fixation compared to Intact in all loading conditions. The polyetheretherketone cage also provided significant fixation when combined with all screw based treatments, however when used with the interspinous process clamp a significant reduction was not observed in lateral bending or axial torsion.

INTERPRETATION

Interbody cages with integrated fixation components enhance post-operative stability within the intervertebral space, thus affording clinicians the potential to utilize less invasive methods of posterior stabilization when seeking circumferential fusion. Interspinous process clamps, in particular, may reduce peri-operative and post-operative comorbidities compared to screw based constructs. Further study is necessary to corroborate their effectiveness in vivo.

Walter Mercer's (1891-1971) contribution to the surgical treatment of low back pain

In 1936, Walter Mercer described a new method for the operative treatment of patients with spondylolisthesis. Using a transabdominal approach in two patients he inserted iliac crest bone graft into the intervertebral disc. His publication in the Edinburgh Medical Journal caused a furore as the levels operated on did not reflect the description and one of the two patients died post-operatively. However, Mercer continued to promote the operation in his textbooks. The anterior approach to the lumbar spine is now performed routinely. This paper explores Mercer's contribution to anterior spinal surgery.

Prospective evaluation of 1-year outcomes in single-level percutaneous lumbar transfacet screw fixation in the lateral decubitus position following lateral transpsoas interbody fusion

PURPOSE

Lateral transpsoas lumbar interbody fusion (LTIF) is an accepted treatment for degenerative lumbar disc disease. Bilateral percutaneous transfacet (TF) fixation is a promising option for stabilization following LTIF. Here, we describe our experience with this technique and assess the clinical outcomes and efficacy.

METHODS

Thirty-eight consecutive patients were identified who underwent LTIF followed by bilateral percutaneous transfacet fixation in the lateral position. Preoperative and 1-year postoperative VAS scores, and operative data were prospectively recorded. One-year outcomes were also assessed according to the MacNab criteria. Fusion was assessed at 1 year via computed tomography and dynamic radiography. Two-tailed Student's t test was used to compare VAS scores.

RESULTS

Twenty-six patients underwent fusion at L4-5, 11 at L3-4, and one at L2-3; two patients were lost to follow-up. Mean operative time was 148.0 ± 47.9 min; mean blood loss was 33.0 ± 26.1 ml; mean hospital stay was 53.5 ± 51.2 h. Mean preoperative VAS scores for back and leg pain were 7.4 ± 3.0 and 7.0 ± 2.9, respectively; mean postoperative VAS scores for back and leg pain were 1.9 ± 2.4 (p < 0.0001) and 2.0 ± 3.0 (p < 0.0001), respectively. Most (89 %) patients had some relief, 72 % good to excellent and 17 % fair outcomes; eleven percent had little to no relief. There was one postoperative complication (pulmonary embolus). All patients had evidence of solid bony fusion.

CONCLUSIONS

Percutaneous transfacet fixation in the lateral position is a safe and effective alternative for fixation after LTIF and may be associated with shorter operative time and less blood loss than other posterior fixation techniques.

Clinical outcomes and fusion rates following anterior lumbar interbody fusion with bone graft substitute i-FACTOR, an anorganic bone matrix/P-15 composite

Object

Despite limited availability and the morbidity associated with autologous iliac crest bone graft (ICBG), its use in anterior lumbar interbody fusion (ALIF) procedures remains the gold standard to achieve arthrodesis. The search for alternative grafts yielding comparable or superior fusion outcomes with fewer complications continues. In particular, i-FACTOR, a novel bone graft substitute composed of anorganic bone matrix (ABM) with P-15 small peptide, is one example currently used widely in the dental community. Although preclinical studies have documented its usefulness, the role of i-FACTOR in ALIF procedures remains unknown.

The authors' goal was to determine the safety and efficacy of i-FACTOR bone graft composite used in patients who underwent ALIF by evaluating fusion rates and clinical outcomes.

Methods

A nonblinded cohort of patients who were all referred to a single surgeon's practice was prospectively studied. One hundred ten patients with degenerative spinal disease underwent single or multilevel ALIF using the ABM/P-15 bone graft composite with a mean of 24 months (minimum 15 months) of follow-up were enrolled in the study. Patient's clinical outcomes were assessed using the Oswestry Disability Index for low-back pain, the 12-Item Short Form Health Survey, Odom's criteria, and a visual analog scale for pain. Fine-cut CT scans were used to evaluate the progression to fusion.

Results

All patients who received i-FACTOR demonstrated radiographic evidence of bony induction and early incorporation of bone graft. At a mean of 24 months of follow-up (range 15–43 months), 97.5%, 81%, and 100% of patients, respectively, who had undergone single-, double-, and triple-level surgery exhibited fusion at all treated levels. The clinical outcomes demonstrated a statistically significant (p < 0.05) difference between preoperative and postoperative Oswestry Disability Index, 12-Item Short Form Health Survey, and visual analog scores.

Conclusions

The use of i-FACTOR bone graft substitute demonstrates promising results for facilitating successful fusion and improving clinical outcomes in patients who undergo ALIF surgery for degenerative spinal pathologies.

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.

Bone graft substitutes for anterior lumbar interbody fusion

The procedure of anterior lumbar interbody fusion (ALIF) is commonly performed on patients suffering from pain and/or neurological symptoms associated with disorders of the lumbar spine caused by disc degeneration and trauma. Surgery is indicated when prolonged conservative management proves ineffective. Because an important objective of the ALIF procedure is solid arthrodesis of the degenerative spinal segment, bone graft selection is critical. Iliac crest bone grafts (ICBG) remain the "gold standard" for achieving lumbar fusion. However, patient dissatisfaction stemming from donor site morbidity, lengthier operating times and finite supply of ICBG has prompted a search for better alternatives. Here presented is a literature review evaluating available bone graft options assessed within the clinical setting. These options include autografts, allograft-based, synthetic and cell-based technologies. The emphasis is on the contentious use of recombinant human bone morphogenetic proteins, which is in widespread use and has demonstrated both significant osteogenic potential and risk of complications.

Surgical management of minimally invasive anterior lumbar interbody fusion with stand-alone interbody cage for L4-5 degenerative disorders: clinical and radiographic findings

Surgical treatment for degenerative spinal disorders is controversial, although lumbar fusion is considered an acceptable option for disabling lower back pain. Patients underwent instrumented minimally invasive anterior lumbar interbody fusion (mini-ALIF) using a retroperitoneal approach except for requiring multilevel fusions, severe spinal canal stenosis, high-grade spondylolisthesis, and a adjacent segments disorders. We retrospectively reviewed the clinical records and radiographs of 142 patients who received mini-ALIF for L4-5 degenerative lumbar disorders between 1998 and 2010. We compared preoperative and postoperative clinical data and radiographic measurements, including the modified Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back and leg pain, disc height (DH), whole lumbar lordosis (WL), and vertebral wedge angle (WA). The mean follow-up period was 76 months. The solid fusion rate was 90.1% (128/142 patients). The average length of hospital stay was 6.9 days (range, 3–21 days). The mean blood loss was 63.7 ml (range, 10–456 ml). The mean operation time was 155.5 min (range, 96–280 min). The postoperative JOA and VAS scores for back and leg pain were improved compared with the preoperative scores. Radiological analysis showed significant postoperative improvements in DH, WL, and WA, and the functional and radiographical outcomes improved significantly after 2 years. The 2.8% complication rate included cases of wound infection, liquorrhea, vertebral body fractures, and a misplaced cage that required revision. Mini-ALIF was found to be associated with improved clinical results and radiographic findings for L4-5 disorders. A retroperitoneal approach might therefore be a valuable treatment option.

Indications for anterior lumbar interbody fusion

Anterior lumbar interbody fusion (ALIF) has become a widely recognized surgical technique for degenerative pathology of the lumbar spine. Spinal fusion has evolved dramatically ever since the first successful internal fixation by Hadra in 1891 who used a posterior approach to wire adjacent cervical vertebrae in the treatment of fracture-dislocation. Advancements were made to reduce morbidity including bone grafting substitutes, metallic hardware instrumentation and improved surgical technique. The controversy regarding which surgical approach is best for treating various pathologies of the lumbar spine still exists. Despite being an established treatment modality, current indications of ALIF are yet to be clearly defined in the literature. This article discusses the current literature on indications on ALIF surgery.

Current status of bone graft options for anterior interbody fusion of the cervical and lumbar spine

Anterior cervical discectomy and fusion (ACDF) and anterior lumbar interbody fusion (ALIF) are common surgical procedures for degenerative disc disease of the cervical and lumbar spine. Over the years, many bone graft options have been developed and investigated aimed at complimenting or substituting autograft bone, the traditional fusion substrate. Here, we summarise the historical context, biological basis and current best evidence for these bone graft options in ACDF and ALIF.

Current concepts on spinal arthrodesis in degenerative disorders of the lumbar spine

Back pain is a common chronic disorder that represents a large burden for the health care system. There is a broad spectrum of available treatment options for patients suffering from chronic lower back pain in the setting of degenerative disorders of the lumbar spine, including both conservative and operative approaches. Lumbar arthrodesis techniques can be divided into sub-categories based on the part of the vertebral column that is addressed (anterior vs posterior). Furthermore, one has to differentiate between approaches aiming at a solid fusion in contrast to motion-sparing techniques with the proposed advantage of a reduced risk of developing adjacent disc disease. However, the field of application and long-term outcomes of these novel motion-preserving surgical techniques, including facet arthroplasty, nucleus replacement, and lumbar disc arthroplasty, need to be more precisely evaluated in long-term prospective studies. Innovative surgical treatment strategies involving minimally invasive techniques, such as lateral lumbar interbody fusion or transforaminal lumbar interbody fusion, as well as percutaneous implantation of transpedicular or transfacet screws, have been established with the reported advantages of reduced tissue invasiveness, decreased collateral damage, reduced blood loss, and decreased risk of infection. The aim of this study was to review well-established procedures for lumbar spinal fusion with the main focus on current concepts on spinal arthrodesis and motion-sparing techniques in degenerative disorders of the lumbar spine.

L5 spondylolysis/spondylolisthesis: a comprehensive review with an anatomic focus

INTRODUCTION

Spondylolysis is most commonly observed in the lumbar spine, particularly L5, and is associated with spondylolisthesis, or anterior "slippage" of a vertebra in relation to an adjacent vertebra. Isthmic spondylolisthesis is the result of a pars interarticularis defect and will be the only type of spondylolisthesis addressed in this review.

CONCLUSIONS

Spondylolysis and spondylolisthesis represent a relatively common cause of low back pain, especially in young athletes, and a less common cause of neurologic compromise. When discovered in a symptomatic patient with corroborating imaging findings, early intervention provides an excellent prognosis. Herein, we review the anatomy and pathology of spondylosis and spondylolisthesis of the L5 vertebra.

Are stand-alone cages sufficient for anterior lumbar interbody fusion?

Anterior lumbar interbody fusion (ALIF) has increased in popularity because it has advantages over posterior fusion. Because there is disagreement about the stability of stand-alone cage ALIF, some surgeons use various types of supplementary fixation, including anterior plates, pedicle screw systems and translaminar screws, to increase segmental stability. Many factors associated with both the cages and endplates influence the time of onset and extent of subsidence after use of stand-alone cage ALIF. A large round cage with an adequate central opening is recommended to facilitate maximum contact with the periphery of the endplate. With regard to the relationship between radiographic fusion and recurrence of symptoms with the development of subsidence, most researchers have reported finding no correlation. Subsidence may be due to a process of bone incorporation between cages and endplates. Does subsidence or nonfusion really matter clinically? Further prospective, randomized controlled trials are very much needed to answer these questions.

Complications of anterior lumbar surgery

The incidence of anterior lumbar surgery is increasing. Although adverse events are uncommon, several have been described. Complications can be categorized based on the time of occurrence (ie, intraoperative, postoperative), patient positioning, surgical exposure, and spinal procedure. Notable approach-related complications involve vascular, visceral, and neural structures. Abdominal complications have been reported. Clinically significant complications related to spinal decompression and reconstruction consist primarily of neurologic injuries and graft- and device-related problems. The rate of complications is higher in the setting of revision anterior surgery than with initial anterior lumbar surgery. A thorough understanding of the complications associated with anterior lumbar surgery will aid in prevention, recognition, and management of these rare problems. The assistance of a vascular, neurologic, or general surgeon may be helpful in avoiding or effectively managing complications.

[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.

Changes in abdominal vascular tension associated with various leg positions in the anterior lumbar approach: cadaver study

STUDY DESIGN

A descriptive cadaveric study measuring arterial tension.

OBJECTIVE

Anterior lumbar surgery is technically challenging due to perioperative vascular complications. Many studies suggest approaches based on the anatomy of the abdominal vessel for safe vascular mobilization. However, the tension in the vascular structure is also important for adequate exposure of the target lesion. It has been established that the tension in the lumbar nerve at the root level can be changed by a straight leg raise test and that the structure of the vascular connection is similar to that of the neural connection. Consequently, a change in leg position could affect the tension of lumbosacral vessels. The purpose of this study was to evaluate the effect of leg position on the tension of lumbosacral vessels.

METHODS

We dissected 10 unembalmed cadavers using the method described by Gumbs et al, using the Synframe system to expose the abdominal artery and vein. The left iliac artery and the distal abdominal aorta were retracted to the right side at the L4-L5 disc level by a measuring retractor to which a strain gauge was attached. The tension was checked at various angles of the hip joint and the motions of the abdominal arteries were monitored in 4 unembalmed cadavers using a C-arm fluoroscope.

RESULTS

The tension in the abdominal aorta at L4-L5 level was decreased by 2.9% to 21.8% in the hip-flexion position, and the motion of the arteries showed proximal displacement of the external iliac artery and the common iliac artery during the hip-flexed position and veins also showed the same pattern of displacement as artery.

CONCLUSION

The results of this study would be useful for not only spinal surgery but also other vascular surgeries, particularly, in cases where patients with conditions such as atherosclerosis or stenosis.

An analysis of general surgery-related complications in a series of 412 minilaparotomic anterior lumbosacral procedures

OBJECT

Anterior lumbar surgery is associated with certain perioperative visceral and vascular complications. The aim of this study was to document all general surgery-related adverse events and complications following minilaparotomic retroperitoneal lumbar procedures and to discuss strategies for their management or prevention.

METHODS

The authors analyzed data obtained in 412 patients who underwent anterior lumbosacral surgery between 2003 and 2005. The series comprised 114 men and 298 women whose mean age was 56 years (range 34-79 years). Preoperative diagnoses were as follows: isthmic spondylolisthesis (32%), degenerative spondylolisthesis (24%), instability/stenosis (15%), degenerative disc disease (15%), failed-back surgery syndrome (7%), and lumbar degenerative kyphosis or scoliosis (7%). A single level was exposed in 264 patients (64%), 2 in 118 (29%), and 3 or 4 in 30 (7%). The average follow-up period was 16 months.

RESULTS

Overall, 52 instances of complications and adverse events occurred in 50 patients (12.1%), including sympathetic dysfunction in 25 (6.06%), vascular injury repaired with/without direct suture in 12 (2.9%), ileus lasting > 3 days in 5 (1.2%), pleural effusion in 4 (0.97%), wound dehiscence in 2 (0.49%), symptomatic retroperitoneal hematoma in 2 (0.49%), angina in 1 (0.24%), and bowel laceration in 1 patient (0.24%). There was no instance of retrograde ejaculation in male patients, and most complications had no long-term sequelae.

CONCLUSIONS

This report presents a detailed analysis of complications related to anterior lumbar surgery. Although the incidence of complications appears low considering the magnitude of the procedure, surgeons should be aware of these potential complications and their management.

Prospective evaluation of transabdominal percutaneous lumbar discectomy for L5–S1 disc herniation: initial clinical experience

Object

Anterior approaches to the lumbosacral spine have become an increasingly common procedure in spine surgery, but transabdominal percutaneous lumbar discectomy (TPLD) performed anteriorly under fluoroscopic guidance is challenging. In this study the authors describe the TPLD and evaluate its safety and early clinical results in the management of L5–S1 disc herniation.

Methods

Between January 2005 and June 2007, 30 consecutive patients with L5–S1 disc herniation were treated with L5–S1 TPLD. All procedures were performed with the patient in a state of local anesthesia. After bowel preparation, the hypogastrium was compressed to move the intestinal canal away from the puncture site. The TPLD was then performed with fluoroscopic guidance to remove herniated disc material. Patients were evaluated prospectively using the visual analog scale (VAS) and the Oswestry Disability Index (ODI) during ≤ 30 months of follow-up.

Results

The mean hospital stay was 6.7 days. Scores on the VAS for leg pain (preoperative mean score 7.10, postoperative mean score 0.93) and the ODI (preoperative mean index 62.03, postoperative mean index 10.33) were statistically significantly (p = 0.00) improved at the last follow-up examination compared with preoperative scores. All members of the study group showed favorable results. On the day after the procedure pancreatitis developed in 1 patient but was cured by fasting and intravenous nutrition with antibiotics for 7 days. No other complications occurred during the follow-up.

Conclusions

Transabdominal percutaneous lumbar discectomy is a safe, effective, and minimally invasive procedure for the treatment of disc herniations at the L5–S1 level.

Mini-open anterior spine surgery for anterior lumbar diseases

Minimally invasive surgeries including endoscopic surgery and mini-open surgery are current trend of spine surgery, and its main advantages are shorter recovery time and cosmetic benefits, etc. However, mini-open surgery is easier and less technique demanding than endoscopic surgery. Besides, anterior spinal fusion is better than posterior spinal fusion while considering the physiological loading, back muscle function, etc. Therefore, we aimed to introduce the modified “mini-open anterior spine surgery” (MOASS) and to evaluate the feasibility, effectiveness and safety in the treatment of various anterior lumbar diseases with this technique. A total of 61 consecutive patients (46 female, 15 male; mean age 58.2 years) from 1997 to 2004 were included in this study, with an average follow-up of 24–52 (mean 43) months. The disease entities included vertebral fracture (20), failed back surgery (13), segmental instability or spondylolisthesis (10), infection (8), herniated disc (5), undetermined lesion for biopsy (4), and hemivertebra (1). Lesions involved 13 cases at T12–L1, 18 at L1–L2, 18 at L2–L3, 22 at L3–L4 and 11 at L4–L5 levels. All patients received a single stage anterior-only procedure for their anterior lumbar disease. We used the subjective clinical results, Oswestry disability index, fusion rate, and complications to evaluate our clinical outcome. Most patients (91.8%) were subjectively satisfied with the surgery and had good-to-excellent outcomes. Mean operation time was 85 (62–124) minutes, and mean blood loss was 136 (minimal-250) ml in the past 6 years. Hospital stay ranged from 4–26 (mean 10.6) days. Nearly all cases had improved back pain (87%), physical function (90%) and life quality (85%). Most cases (95%) achieved solid or probable solid bony fusion. There were no major complications. Therefore, MOASS is feasible, effective and safe for patients with various anterior lumbar diseases.

Transabdominal Percutaneous L5–S1 Lumbar Discectomy: Interventional Technique, Early Results, and Complications

PURPOSE

Anterior approaches to the lumbosacral spine have become increasingly common in spine surgery, but transabdominal percutaneous lumbar discectomy (TPLD) is challenging. This study describes TPLD and evaluates safety and early clinical results in the management of L5-S1 disc herniation.

MATERIALS AND METHODS

Between October 2001 and October 2006, 58 consecutive patients with L5-S1 disc herniations were treated with TPLD of the L5-S1 discs, and nine of the patients with L4-L5 disc herniations were treated with posterolateral percutaneous lumbar discectomy (PPLD) soon after TPLD. The patients were divided into two groups according the operator who performed the procedures. The patients were evaluated with a visual analog scale (VAS) and the Oswestry Disability Index (ODI) at 5 years of follow-up. Logistic regression was used to analyze significant risk factors for complications.

RESULTS

Mean hospital stay was 6.38 days +/- 8.48. VAS scores for leg pain and ODI scores showed significant improvement at last follow-up. All patients showed favorable results with no recurrent herniations. Major and minor complications occurred in eight (13.79%) and seven cases (12.06%), respectively, during and after the procedure. Major complications occurred in seven patients treated by operator A and one treated by operator B, a significant difference between operators (P = .044). Multivariate analysis revealed that only bowel preparation remained a significant predictor of complications (P = .040).

CONCLUSION

TPLD was a safe and effective procedure for the removal of disc herniations at the L5-S1 level when total bowel preparation was performed.

Minimally invasive techniques for lumbar interbody fusions

Lumbar spinal fusions have been performed for nearly a century for a variety of spinal conditions and include posterior/posterolateral and anterior lumbar interbody fusions. Traditionally, the ability to achieve adequate exposure to perform these procedures required an open surgical approach; however, the advent of newer techniques and technology, combined with an improved understanding of surgical anatomy, has resulted in newer minimally invasive techniques. Posterior approaches include posterior and transforaminal lumbar interbody fusions, whereas anterior techniques include retroperitoneal and transperitoneal anterior lumbar interbody fusion approaches. More recently, the extreme lateral interbody fusion and axial lumbar interbody fusion have been described. This article provides a general review of the history, indications, brief overview, and description of the more common minimally invasive spine surgery techniques used for achieving a lumbar interbody fusion.

Minimally invasive lumbar spinal fusion

Minimally invasive techniques for lumbar spine fusion have been developed in an attempt to decrease the complications related to traditional open exposures (eg, infection, wound healing problems). Anterior minimally invasive procedures include laparoscopic and mini-open anterior lumbar interbody fusion as well as the lateral transpsoas and percutaneous presacral approaches. Posterior techniques typically use a tubular retractor system that avoids the muscle stripping associated with open procedures. These techniques can be applied to both posterior and transforaminal lumbar interbody fusion procedures. Many initial reports have shown similar clinical results in terms of spinal fusion rates for both traditional open and minimally invasive posterior approaches. However, the anterior minimally invasive procedures are often associated with significantly greater incidence of complications and technical difficulty than their associated open approaches. There is a steep learning curve associated with minimally invasive techniques, and surgeons should not expect to master them in the first several cases.

PLIF With a Titanium Cage and Excised Facet Joint Bone for Degenerative Spondylolisthesis—In Augmentation With a Pedicle Screw

OBJECTIVES

To determine the validity of posterior lumbar interbody fusion (PLIF) using a titanium cage filled with excised facet joint bone and a pedicle screw for degenerative spondylolisthesis.

METHODS

PLIF using a titanium cage filled with excised facet joint bone and a pedicle screw was performed in 28 consecutive patients (men 10, women 18). The mean age of the patients was 60 years (range, 52 to 75 y) at the time of surgery. The mean follow-up period was 2.3 years (range, 2.0 to 4.5 y). The operation was done at L3/4 in 5, L4/5 in 20, and L3/4/5 in 3 patients. The mean operative bleeding was 318+/-151 g (mean+/-standard deviation), and the mean operative time was 3.34+/-0.57 hours per fixed segment. Clinical outcome was assessed by Denis' Pain and Work scale. Radiologic assessment was done using Boxell's method. Fusion outcome was assessed using an established criteria.

RESULTS

On Pain scale, 20 and 8 patients were rated P4 and P5 before surgery, and 11, 12, 2, 2, and 1 patients were rated P1, P2, P3, P4, and P5 at final follow-up, respectively. On Work scale (for only physical labors), 12 and 9 patients were rated W4 and W5, before surgery, and 12, 5, 1, and 3 patients were rated W1, W2, W3 and W5 at final follow-up, respectively. There was significant difference in clinical outcome (P<0.01, Wilcoxon singled-rank test) The mean %Slip and Slip Angle was 17.9+/-8.1% and 3.9+/-5.8 degrees before surgery. The mean % Slip and Slip Angle was 5.4+/-4.4% and -2.0+/-4.8 degrees at final follow-up. There was a significant difference between the values (P<0.01, paired t test). "Union" and "probable union" was determined in 29 (93.5%) and 2 (6.5%) of 31 operated segments at 2.3 years (range, 2.0 to 4.5 y), postoperatively.

CONCLUSIONS

PLIF using a titanium cage filled with excised facet joint bone and a pedicle screw provided a satisfactory clinical outcome and an excellent union rate without harvesting and grafting the autologous iliac bone.

Application of polylactides in spinal cages: studies in a goat model

Spinal cages are currently made of non-resorbable materials, but they only have a temporary function: after fusion, resorption is desirable both from a biological and mechanical point of view. We studied different polylactides in stand-alone condition in a goat model. Cages were made of 100% poly(L-lactic acid) (PLLA) or 70/30 poly(L/DL-Lactic acid) (PLDLLA); titanium served as control. After six months, all titanium cages showed non-unions comparable to that observed in a clinical retrieval, thus showing validity of the goat model. PLLA cages maintained their mechanical integrity for six months, enough to allow fusion. After that, the material resorbed within 48 months without adverse tissue reactions. Bone formation was faster in PLDLLA cages, but these already failed within three months, thus losing their stabilising function: 50% ended in pseudo-arthrosis. Additional internal fixation provided enough stability for fusion (83%). Biocompatibility of both PLLA and PLDLLA was excellent. The long-term results show that PLLA cages can be used for stand-alone interbody fusion, and that PLLA is an improvement over titanium in terms of fusion rate. PLDLLA showed enhanced bone formation, but also earlier failure of the implant. Chances for spinal fusion were better with additional internal fixation.

An evaluation of vascular anatomy for minilaparotomic anterior L4–5 procedures

Object

The complexity of the vascular anatomy pertinent to the L4–5 intervertebral disc space has led to difficulties when performing the anterior approach to the lumbar spine. The purpose of the present study was to evaluate the variations of the great vessels to match the imaging-documented axial anatomy with the surgical exposure.

Methods

The authors analyzed data obtained in 223 patients who had undergone mini–open anterior lumbar surgery involving the L4–5 disc. The preoperative magnetic resonance images or computed tomography scans were evaluated by examiners blinded to the surgical approach to determine the vascular configuration. All complications of the procedures were described.

Two major variations of the vascular configuration were delineated according to the location of the bifurcation of the inferior vena cava. On images showing the lower margin of the L-4 vertebra, the anatomy in 182 patients (81%) was classified as Type A because the inferior vena cava (IVC) was not bifurcated; in 38 patients (17%) it was classified as Type B because the IVC was bifurcated. Type A could be subdivided into Types A1 and A2 according to whether the aorta was bifurcated (A2) or not (A1) on the same image. The surgical exposure used was above the bifurcations (in Type A) and below the bifurcations (in Type B). The major complications were three venous injuries, and the leading complication was sympathetic dysfunction in 14 patients, which in most cases resolved spontaneously.

Conclusions

Careful preoperative evaluation of the vascular anatomy is essential to conducting successful anterior lumbar surgery. The determination of an appropriate approach can contribute to a reduction of unnecessary vascular retraction and a consequent decrease in vascular complications.

Supplementary stabilization with anterior lumbar intervertebral fusion--a radiologic review

STUDY DESIGN

A radiologic assessment of the success of anterior lumbar interbody fusion (ALIF) using thin-section computerized tomography (CT) was performed.

OBJECTIVE

To assess the effect of different types of posterior stabilization on the fusion rate of ALIF.

SUMMARY OF BACKGROUND DATA

Thin-section CT has shown a higher rate of pseudarthrosis with ALIF than previously reported with standard radiologic methods. Cadaveric studies have shown that posterior stabilization would increase stiffness of the motion segment and is likely to enhance the rate of fusion with ALIF. To our knowledge, the results of thin-section CT of ALIF, with and without posterior stabilization, has not been reported previously.

METHODS

Patients with discogenic back pain confirmed by diskography underwent ALIF surgery, either as a stand-alone procedure or with posterior stabilization, using translaminar, unilateral pedicle, or bilateral pedicle screws. The 4 cohorts were followed up prospectively, and thin-section CT was used to assess interbody fusion.

RESULTS

The fusion rate for stand-alone ALIF was 51%, for patients with supplementary stabilization with translaminar screws 58%, with unilateral pedicle screws 89%, and with bilateral pedicle screws 88%. A significant difference in the fusion rate was found when ALIF was combined with pedicle screw stabilization (P < 0.01).

CONCLUSION

The addition of pedicle screw fixation at ALIF produces a significant increase in the rate of interbody fusion.

[Degenerative disorders of the lumbar spine Total disc replacement as an alternative to lumbar fusion?]

Spinal fusion is accepted worldwide as a therapeutic option for the treatment of degenerative disorders of the lumbar spine. Because there are only few evidence-based data available supporting the usefulness of lumbar spinal fusion, its questionable benefit as well as the potential for complications are the reasons for an ongoing discussion. In recent years, total disc replacement with implants has emerged as an alternative treatment. Although early results are promising, there is still a lack of evidence-based data as well as of long-term results for this technology. This article gives a critical update on the implant systems currently in use (SB Charité, Prodisc II L, Maverick, Flexicore, Mobidisc), which all have to be considered as "first-generation" implants. Morphological and clinical sequelae of the different biomechanical properties, designs, and materials have not yet been sufficiently investigated. There is no international consensus on the indication spectrum and on the preoperative diagnosis of discogenic low back pain. The same is true for the (minimally invasive) surgical access strategies. Complication rates seem to be somewhat lower compared to spinal fusion techniques. There are no standardized revision concepts in cases of implant failure. Lumbar disc replacement has opened a new era in spinal surgery with a still unproven benefit for the patient. It is strongly recommended that these techniques should only be applied by experienced and well-trained spine surgeons. Until evidence-based data are available, all patients should be treated under scientific study conditions with close postoperative follow-up.

Advances in spinal fusion

Since its initial description about a century ago, spinal fusion has become a common surgical intervention in the treatment of various debilitating spinal disorders. However, given the complexities and demands of the procedure, patient selection remains a key component in the success of the operation. In this article, we will review the various indications for spinal fusion, the current advances in fusion techniques, as well as the potential complications associated with the procedure.

Epidural abscess and discitis complicating instrumented posterior lumbar interbody fusion: a case report

STUDY DESIGN

A case of epidural abscess and discitis following instrumented PLIF using a single carbon fiber interbody cage is presented.

OBJECTIVE

To describe a previously unreported complication of epidural abscess and discitis following posterior lumbar interbody fusion using a single carbon fiber cage.

SUMMARY OF BACKGROUND DATA

Various complications have been reported with PLIF. These include graft migration, pseudarthrosis, implant subsidence, epidural hemorrhage, incidental durotomy, arachnoiditis, transient or permanent neurologic deficits, persistence of pain, and wound infections. There are no reported cases of epidural abscess or refractory discitis associated with PLIF.

METHODS

A 35-year-old infantryman on active duty with chronic low back pain and single-level lumbar disc degeneration underwent instrumented PLIF after reporting no improvement with 3 years of extension-based physical therapy and nonsteroidal pain medications. His back pain was reported improved at 6 weeks after surgery. At 12 weeks after surgery, he presented to the emergency department with intense back pain and fevers. Laboratory data were remarkable for elevated erythrocyte sedimentation rate (118) and C-reactive protein (38). Initial imaging studies, including a lumbar MRI, did not demonstrate any abnormalities. The patient continued to spike fevers, and a repeat lumbar MRI 1 week later clearly demonstrated the presence of an epidural abscess at the level of the PLIF surgery. The patient was treated with surgical debridement and epidural abscess drainage. The interbody cage was left in place. Surgical cultures identified Staphylococcus aureus as the pathogen, and the patient was placed on intravenous vancomycin. During the ensuing 3 weeks, his clinical symptoms worsened and his radiographs demonstrated lucency in the region of his interbody cage. Repeat debridement was performed, and his interbody cage and pedicle screw instrumentation were removed 4 months after initial surgery.

RESULTS

The disc space infection resolved following removal of the implants. Radiographs at 6 months after instrumentation removal demonstrated solid bilateral posterolateral arthrodesis. The patient returned to active duty 1 year after his initial surgery, reporting that his back pain was reduced compared with his preoperative level.

CONCLUSIONS

There is a paucity of literature on epidural abscess and discitis as complications associated with PLIF. In this case, the infection persisted despite surgical debridement and intravenous antibiotics. The patient ultimately required removal of the interbody implant and posterior instrumentation. The patient developed solid posterolateral arthrodesis despite the presence of deep infection, which led to early implant removal 4 months after the initial surgery. This case underscores the potential importance of concomitant posterolateral fusion, particularly following wide laminectomy and facetectomy required for PLIF.

Anterior Lumbar Interbody Fusion for Treatment of Failed Back Surgery Syndrome: An Outcome Analysis

OBJECTIVE

Anterior lumbar interbody fusion (ALIF) has gained popularity for the treatment of degenerative disease of the lumbar spine. In this report, we present our experience with the ALIF procedure for treatment of failed back surgery syndrome (FBSS) in a noncontrolled prospective cohort.

METHODS

In a 2-year period, we treated patients diagnosed with FBSS with ALIF. Clinical and radiological outcomes were recorded in a prospective, nonrandomized, longitudinal manner. Neurological, pain, and functional outcomes were measured preoperatively and 12 months after surgery. Operative data, perioperative complications, and radiological and clinical outcomes were recorded.

RESULTS

Thirty-three patients with a preoperative diagnosis of FBSS, with degenerative disc disease (n = 17), postsurgical spondylolisthesis (n = 13), or pseudarthrosis (n = 3), underwent ALIF. Back pain, leg pain, and functional status improved significantly, by 76% (P &lt; 0.01), 80% (P &lt; 0.01), and 67% (P &lt; 0.01), respectively.

CONCLUSION

On the basis of our results, we found ALIF to be a safe and effective procedure for the treatment of FBSS for selected patients.

Minimally invasive lumbar fusion

STUDY DESIGN

Review article.

OBJECTIVES

To provide an overview of current techniques for minimally invasive lumbar fusion.

SUMMARY OF BACKGROUND DATA

Minimally invasive techniques have revolutionized the management of pathologic conditions in various surgical disciplines. Although these same principles have been used in the treatment of lumbar disc disease for many years, minimally invasive lumbar fusion procedures have only recently been developed. The goals of these procedures are to reduce the approach-related morbidity associated with traditional lumbar fusion, yet allow the surgery to be performed in an effective and safe manner.

METHODS

The authors' clinical experience with minimally invasive lumbar fusion was reviewed, and the pertinent literature was surveyed.

RESULTS

Minimally invasive approaches have been developed for common lumbar procedures such as anterior and posterior interbody fusion, posterolateral onlay fusion, and internal fixation. As with all new surgical techniques, minimally invasive lumbar fusion has a learning curve. As well, there are benefits and disadvantages associated with each technique. However, because these techniques are new and evolving, evidence to support their potential benefits is largely anecdotal. Additionally, there are few long-term studies to document clinical outcomes.

CONCLUSIONS

Preliminary clinical results suggest that minimally invasive lumbar fusion will have a beneficial impact on the care of patients with spinal disorders. Outcome studies with long-term follow-up will be necessary to validate its success and allow minimally invasive lumbar fusion to become more widely accepted.

A surgical revisitation of Pott distemper of the spine

BACKGROUND CONTEXT

Pott disease and tuberculosis have been with humans for countless millennia. Before the mid-twentieth century, the treatment of tuberculous spondylitis was primarily supportive and typically resulted in dismal neurological, functional and cosmetic outcomes. The contemporary development of effective antituberculous medications, imaging modalities, anesthesia, operative techniques and spinal instrumentation resulted in quantum improvements in the diagnosis, management and outcome of spinal tuberculosis. With the successful treatment of tuberculosis worldwide, interest in Pott disease has faded from the surgical forefront over the last 20 years. With the recent unchecked global pandemic of human immunodeficiency virus, the number of tuberculosis and secondary spondylitis cases is again increasing at an alarming rate. A surgical revisitation of Pott disease is thus essential to prepare spinal surgeons for this impending resurgence of tuberculosis.

PURPOSE

To revisit the numerous treatment modalities for Pott disease and their outcomes. From this information, a critical reappraisal of surgical nuances with regard to decision making, timing, operative approach, graft types and the use of instrumentation were conducted.

STUDY DESIGN

A concise review of the diagnosis, management and surgical treatment of Pott disease.

METHODS

A broad review of the literature was conducted with a particular focus on the different surgical treatment modalities for Pott disease and their outcomes regarding neurological deficit, kyphosis and spinal stability.

RESULTS

Whereas a variety of management schemes have been used for the debridement and reconstruction of tuberculous spondylitis, there has also been a spectrum of outcomes regarding neurological function and deformity. Medical treatment alone remains the cornerstone of therapy for the majority of Pott disease cases. Surgical intervention should be limited primarily to cases of severe or progressive deformity and/or neurological deficit. Based on the available evidence, radical ventral debridement and grafting appears to provide reproducibly good long-term neurological outcomes. Furthermore, recurrence of infection is lowest with such techniques. Posterior operative techniques are most effective in the reduction and prevention of spinal deformity.

CONCLUSIONS

Unlike historical times, effective medical and surgical management of tuberculous spondyitis is now possible. Proper selection of drug therapy and operative modalities, however, is needed to optimize functional outcomes for each individual case of Pott disease.

Microsurgical Anterior Approaches to the Lumbar Spine for Interbody Fusion and Total Disc Replacement

OBJECTIVE

Anterior approaches to the lumbar spine for the treatment of various degenerative or postoperative abnormalities associated with low back pain have always been a matter of debate. They are known to be associated with considerable surgical trauma, high postoperative morbidity, and, occasionally, unacceptably high complication rates. In 1997, we inaugurated two new microsurgical modifications of conventional anterior approach techniques, which have been applied in anterior lumbar interbody fusion and more recently in total disc replacement. This article describes the results of microsurgical anterior interbody fusion in a consecutive series of 171 patients as well as preliminary results of these techniques for total disc replacement in 26 patients.

METHODS

The approaches are performed with the use of a surgical microscope. Lumbar segments L2–L5 are exposed through a lateral retroperitoneal approach. L5–S1 can be reached through a midline retroperitoneal or transperitoneal approach. Both approaches can be performed through a limited skin incision of 4 cm.

RESULTS

An independent observer evaluated results of anterior lumbar interbody fusion in 171 patients during a 2-year follow-up period. The clinical follow-up demonstrated low perioperative and postoperative morbidity with an average blood loss of less than 100 ml at the fusion site. Pseudoarthrosis rates were less than 5%, and clinical results, as evaluated in accordance with the scoring system developed by Prolo et al., did not differ significantly from conventional open techniques. Total disc replacement through a microsurgical anterior approach seems to be a promising alternative to fusion procedures with even less intraoperative and perioperative morbidity.

CONCLUSION

Microsurgical anterior approaches to the lumbar spine provide a reasonable surgical alternative to conventional approaches for anterior interbody fusion and total disc replacement.

Laparoscopic lateral L4-L5 disc exposure

BACKGROUND

The anterior laparoscopic approach requires precarious dissection around the iliac vessels to expose the L4-L5 level. Furthermore, a retroperitoneal endoscopic approach to the L4-L5 level requires a technically demanding dissection to access the L5-S1 disc space. A unique lateral laparoscopic approach to the L4-L5 disc space allows concurrent access to the L5-S1 space while avoiding major dissection around the iliac vessels. This article describes this novel lateral approach and reviews the initial clinical outcomes.

METHODS

Between January 1999 and April 2000, five patients underwent laparoscopic lateral L4-L5 disc exposure at the Cleveland Clinic Foundation. All charts were reviewed retrospectively. Mean values +/- standard deviation were determined for patient demographics and operative characteristics. A standard five-port laparoscopic technique was used. The sigmoid colon was retracted medially with an endoloop. The retroperitoneum was entered and the ureter and left iliac artery were retracted medially, whereas the psoas was retracted laterally. Fluoroscopy delineated the L4-L5 disc space allowing discectomy and cage insertion. Postoperatively, subjective patient satisfaction was obtained and radiologic evidence of fusion was assessed.

RESULTS

All five patients were males, with a mean age of 47.4 +/- 7 years and a body mass index of 30 +/- 6 kg/m2. Four patients had an L4-L5 and L5-S1 fusion and one patient had an L4-L5 and L3-L4 fusion. Mean operative time was 349 +/- 32 min, with a mean blood loss of 210 +/- 74 cc. There were no intraoperative complications and no conversions, and postoperatively all patients were started on a clear liquid diet on postoperative day 1. The mean length of stay was 3.4 +/- 0.9 days. Patients returned to work in a mean of 12 +/- 7 weeks. All patients had evidence of fusion on their radiologic follow-up. Four patients were pain free, whereas one patient required intermittent narcotics at 1-year follow-up.

CONCLUSIONS

For multilevel fusions including the L4-L5 disc space, the lateral laparoscopic exposure is a safe and efficacious procedure allowing simultaneous access to multiple disc spaces while avoiding the sympathetic chain, ureter, and major vascular structures. The lateral approach affords excellent exposure for accurate deployment of the appropriate orthopedic hardware.

Salvage reconstruction with vascularized fibular strut graft fusion using posterior approach in the treatment of severe spondylolisthesis

STUDY DESIGN

One case is reported in which a failed anterior fusion for Grade 4 spondylolisthesis was treated with a vascularized fibular strut graft using a posterior approach.

OBJECTIVES

To demonstrate the applicability of this technique for salvage cases or patients with systemic conditions that may decrease the success of more standard techniques.

SUMMARY OF BACKGROUND DATA

Surgical stabilization of spondylolisthesis through posterior approach with a fibular strut graft has been previously described. A vascularized strut graft can be used in the treatment of spondylolisthesis and may have applicability in those patients with underlying disease that may impair the use of more standard techniques or in salvage reconstruction.

METHODS

With the patient under general anesthesia, through a posterior approach S1 and L4 were decompressed. The fibula with its vascularity intact was harvested and anastomosed with the superior gluteal artery and vein. The fibular strut was placed into the space formed by reaming between L5 and S1. Ilial autograft was used to augment the posterior fusion. After the procedure the patient was placed in a hip spica cast.

RESULTS

At the 2-year follow-up the patient has incorporation of the graft, with no evidence of fracture and no significant progression of anterior slip.

CONCLUSION

A vascularized fibular strut graft is a feasible alternative in the treatment of severe spondylolisthesis. No complications were encountered in the involved patient. Future application may include salvage reconstruction of failed arthrodesis or in individuals with systemic conditions that may impair graft incorporation using more standard techniques.

The axial cage. a pilot study for interbody fusion in higher-grade spondylolisthesis

BACKGROUND CONTEXT

The surgical treatment of high-grade spondylolisthesis is challenging. Posterolateral fusion alone has a high rate of pseudarthrosis. Surgical stabilization of higher-grade lumbar spondylolisthesis with a fibula strut graft is an effective technique but is associated with harvest site morbidity and graft fractures.

PURPOSE

We hypothesized that a lumbar interbody fusion with a long, threaded titanium cage, packed with cancellous bone, inserted across the center of the spondylolisthesis, would provide the rigid immobilization necessary for successful arthrodesis. This would, therefore, eliminate the need for fibula harvest and possibly reduce the need for posterior instrumentation.

STUDY DESIGN/SETTING

Prospective, study cohort of 11 consecutive patients with a minimum follow-up of 1 year.

PATIENT SAMPLE

Patients with higher-grade spondylolisthesis (grade II-IV) were considered eligible.

OUTCOME MEASURES

Pain was measured with a 10-point Numerical Rating Score (NRS). The Oswestry Disability Index (OSI) was used to assess patient function. Patients also responded to a satisfaction scale to evaluate satisfaction with their outcome. Radiographs were reviewed 1, 3, 6, 12, and, when available, 24 months after surgery.

METHODS

We reviewed our clinical results and technical outcomes in 11 consecutive patients who underwent this unique form of anterior lumbar interbody fusion with a custom axial cage.

RESULTS

There were no surgical or postoperative complications. Serial x-rays revealed no implant subsidence or loosening. There have been no implant fractures or reoperation. Clinical results have been excellent with significant pain reduction and improved function. At 1 year after surgery the mean NRS was 3.5 (range, 0-7), a significant average reduction of 5.0 points. (p<.001) All patients have been satisfied with their results.

CONCLUSIONS

The axial cage technique appears to be a significant improvement over the fibular strut graft for the treatment of higher-grade spondylolisthesis. It provides significant reduction in pain, significant improvement in function, high patient satisfaction, and avoids the morbidity and fracture risks associated with fibular strut grafting.

Experimental anterior spine fusion using bovine bone morphogenetic protein: a study in rabbits

We developed an experimental model to study the merit of bovine bone morphogenic protein (bBMP) injection into the intervertebral disc to induce anterior interbody fusion. A total of 24 rabbits, divided into three groups of 8 animals each, were used. One hundred and fifty microg of partially purified bBMP was employed in the first group and 10 microg bBMP in the second group. In the control group, a sham operation was performed. The animals were followed radiographically at weekly intervals and animals were killed 3, 6, and 12 weeks postoperatively. After sacrifice, a mechanical and histologic evaluation of fusion was performed. Results of radiographic and histologic evaluation showed bone formation, which had resulted in the bridging of adjacent endplates, in the 150-microg group. In the 10-microg group, new bone formation was less extensive. In the control group, intradiscal bone formation was seen in only 1 animal. Range of motion measurements on flexion/extension films showed significantly decreased motion in segments that were fused with 150-microg of BMP. This study demonstrated the utility of an experimental model which allowed investigation of how anterior spine fusion may be further studied. Intradiscal injection of BMP could ultimately play a role in the development of minimally invasive techniques for anterior spinal fusion.

Laparoscopic lumbar interbody spinal fusion

Laparoscopic ALIF is an evolving technique requiring the participation of a laparoscopic surgeon experienced in advanced laparoscopic techniques and knowledgeable in anterior lumbar spinal exposures. Initial enthusiasm for this technique was fostered by the development of interbody fusion devices and a method of exposing the anterior lumbar spine, which takes advantage of the ability of minimally invasive surgeries to improve exposure and visualization while minimizing collateral tissue damage and injury to healthy tissue. Preliminary studies have demonstrated laparoscopic ALIF feasibility. These same studies have been able to prove only minor advantages with the laparoscopic versus open technique using the current implants and bone grafting techniques for single-level disc disease. General acceptance of laparoscopic ALIF awaits further investigation. Reasons for a lack of general acceptance include the expense of the interbody fusion devices and laparoscopic equipment, the unfamiliarity of this advanced laparoscopic technique to spine and general surgeons, and the steep learning curve of the procedure. Intraoperative complications that arise are often severe, such as vascular injuries. Many skeptics appropriately believe that initial enthusiasm and zealousness must be tempered with scientific effort that provides data from long-term follow-up. For laparoscopic ALIF to gain general acceptance, randomized comparisons of laparoscopic ALIF to open ALIF and posterior lumbar spinal fusion and controlled studies with long-term follow-up documenting symptomatic outcome variables and spinal fusion rates must be completed. As new modalities are developed, minimally invasive techniques may facilitate their utility. The indications, procedures, and surgical principles of ALIF are unchanged, and physicians must not invent indications to justify the technique; however, eventually we may be able to redefine the indications to take full advantage of the endoscopic techniques and biological advances.