Transperitoneal laparoscopic exposure for lumbar interbody fusion

Endoscopic Anterior Lumbar Interbody Fusion: Systematic Review and Meta-Analysis

Laparoscopic anterior lumbar interbody fusion (L-ALIF), which employs laparoscopic cameras to facilitate a less invasive approach, originally gained traction during the 1990s but has subsequently fallen out of favor. As the envelope for endoscopic approaches continues to be pushed, a recurrence of interest in laparoscopic and/or endoscopic anterior approaches seems possible. Therefore, evaluating the current evidence base in regard to this approach is of much clinical relevance. To this end, a systematic literature search was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using the following keywords: "(laparoscopic OR endoscopic) AND (anterior AND lumbar)." Out of the 441 articles retrieved, 22 were selected for quantitative analysis. The primary outcome of interest was the radiographic fusion rate. The secondary outcome was the incidence of perioperative complications. Meta-analysis was performed using RStudio's "metafor" package. Of the 1,079 included patients (mean age, 41.8±2.9 years), 481 were males (44.6%). The most common indication for L-ALIF surgery was degenerative disk disease (reported by 18 studies, 81.8%). The mean follow-up duration was 18.8±11.2 months (range, 6-43 months). The pooled fusion rate was 78.9% (95% confidence interval [CI], 68.9-90.4). Complications occurred in 19.2% (95% CI, 13.4-27.4) of L-ALIF cases. Additionally, 7.2% (95% CI, 4.6-11.4) of patients required conversion from L-ALIF to open surgery. Although L-ALIF does not appear to be supported by studies available in the literature, it is important to consider the context from which these results have been obtained. Even if these results are taken at face value, the failure of endoscopy to have a role in the ALIF approach does not mean that it should not be incorporated in posterior approaches.

Clinical presentation and surgical anatomy of sympathetic nerve injury during lumbar spine surgery: a narrative review

BACKGROUND AND OBJECTIVE

To highlight the surgical anatomy, procedural variations, presentation, and management of sympathetic nerve injury after surgery of the lumbar spine.

METHODS

PubMed and Google Scholar were searched for publications that were completed between 1951 and 2021. Relevant full-text articles published in the English language were selected and critically reviewed.

KEY CONTENT AND FINDINGS

Sympathetic injury is a highly variable postsurgical complication with a greater incidence after an anterior or oblique approach to the lumbar spine compared to posterior and lateral approaches. The direct and extreme lateral approaches reduce the need to disturb sympathetic nerves thus reducing the risk of complications. It can present in multiple manners, including complex regional pain syndrome (CRPS) and retrograde ejaculation. These complications can be transient and resolve spontaneously or be treated with medications, physical therapy, and spinal blocks. The severity of the conditions and extent of recovery can vary drastically, with some patients never fully recovering.

CONCLUSIONS

To access the lumbar spine, there are operational approaches and techniques that should be used to decrease the risk of intraoperative injury. It is crucial to understand the advantages and risks to different approaches and take the necessary steps to minimize complications. Early identification of dysfunction and adequate management of symptoms are imperative to effectively manage patients with lumbar sympathetic trunk and sympathetic nerve fiber injuries.

Sexual activity after spine surgery: a systematic review

INTRODUCTION

Sexual function is an important determinant of quality of life, and factors such as surgical approach, performance of fusion, neurological function and residual pain can affect it after spine surgery. Our aim was to perform a systematic review to collate evidence regarding the impact of spine surgery on sexual function.

METHODS

A systematic review of studies reporting measures of sexual function, and incidence of adverse sexual outcomes (retrograde ejaculation) after major spine surgery was done, regardless of spinal location. Pubmed (MEDLINE) and Google Scholar databases were queried using the following search words "Sex", "Sex life", "Sexual function", "Sexual activity", "retrograde ejaculation", "Spine", "Spine surgery", "Lumbar surgery", "Lumbar fusion", "cervical spine", "cervical fusion", "Spinal deformity", "scoliosis" and "Decompression". All articles published between 1997 and 2017 were retrieved from the database. A total of 81 studies were included in the final review.

RESULTS

Majority of the studies were retrospective case series and were low quality (Level IV) in evidence. Anterior lumbar approaches were associated with a higher incidence of retrograde ejaculation, especially with the utilization of transperitoneal laparoscopic approach. There is inconclusive evidence on the preferred sexual position following fusion, and also on the impact of BMP-2 usage on retrograde ejaculation/sexual dysfunction.

CONCLUSION

Despite limited evidence from high-quality articles, there is a general trend towards improvement of sexual activity and function after spine surgery. Future studies incorporating specific assessments of sexual activity will be required to address this important determinant of quality of life so that appropriate pre-operative counselling can be done by providers. These slides can be retrieved under Electronic Supplementary Material.

Adult Degenerative Lumbar Scoliosis

Adult degenerative lumbar scoliosis is a 3-dimensional deformity defined as a coronal deviation of greater than 10°. It causes significant pain and disability in the elderly. With the aging of the population, the incidence of adult degenerative lumbar scoliosis will continue to increase. During the past decade, advancements in surgical techniques and instrumentation have changed the management of adult spinal deformity and led to improved long-term outcomes. In this article, the authors provide a comprehensive review of the pathophysiology, diagnosis, and management of adult degenerative lumbar scoliosis. [Orthopedics. 2017; 40(6):e930-e939.].

Anterior lumbar spine surgery: a systematic review and meta-analysis of associated complications

BACKGROUND CONTEXT

The anterior approach to the lumbar spine is increasingly used to accomplish various surgical procedures. However, the incidence and risk factors for complications associated with anterior lumbar spine surgery (ALS) have not been fully elucidated.

PURPOSE

To identify and document types of complications and complication rates associated with ALS, determine risk factors for these events, and evaluate the effect of measures used to decrease complication rates.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic review of the English-language literature was conducted for articles published between January 1992 and December 2013. A MEDLINE search was conducted to identify articles reporting complications associated with ALS. For each complication, the data were combined using a generalized linear mixed model with a binomial probability distribution and a random effect based on the study. Predictors used were the type of procedure (open, minimally invasive, or laparoscopic), the approach used (transperitoneal vs. retroperitoneal), use of recombinant bone morphogenetic protein-2, use of preoperative computed tomography angiography (CTA), and the utilization of an access surgeon. Open surgery was used as a reference category.

RESULTS

Seventy-six articles met final inclusion criteria and reported complication rates in 11,410 patients who underwent arthrodesis and/or arthroplasty via laparoscopic, mini-open, and open techniques. The overall complication rate was 14.1%, with intraoperative and postoperative complication rates of 9.1% and 5.2%, respectively. Only 3% of patients required reoperation or revision procedures. The most common complications reported were venous injury (3.2%), retrograde ejaculation (2.7%), neurologic injury (2%), prosthesis related (2%), postoperative ileus (1.4%), superficial infection (1%), and others (1.3%). Laparoscopic and transperitoneal procedures were associated with higher complication rates, whereas lower complication rates were observed in patients receiving mini-open techniques. Our analysis indicated that the use of recombinant bone morphogenetic protein-2 was associated with increased rates of retrograde ejaculation; however, there may be limitations in interpreting these data. Data regarding the use of preoperative CTA and an access surgeon were limited and demonstrated mixed benefit.

CONCLUSIONS

Overall complication rates with ALS are relatively low, with the most common complications occurring at a rate of 1% to 3%. Complication rates are related to surgical technique, approach, and implant characteristics. Further randomized controlled trials are needed to validate the use of preventative measures including CTA and the use of an access surgeon.

Subphrenic hematoma after thoracoscopic discectomy: description of a very rare adverse event and review of the literature on complications

The authors describe a very rare and previously unreported complication of thoracoscopic discectomy. Endoscopic spine surgery has evolved as a safe and effective treatment, and thoracoscopic discectomy, in particular, provides several advantages over open approaches, although it can be associated with intraoperative or postoperative complications. The most frequently observed adverse events are intercostal neuralgia, retained disc fragments, durotomies, atelectasis, extensive bleeding, and emergency conversion to open thoracotomy for vascular injuries. Even rare complications, such as chylorrhea or brain hemorrhagic infarction, have been reported. Nonetheless, a literature review did not reveal any case of postoperative intraabdominal hematoma following thoracoscopic discectomy. A 43-year-old woman, with no history of hematological or vascular disorders or thoracic surgery, underwent a right-sided thoracoscopic discectomy for T11–12 disc herniation. No apparent surgical technique–related complications were encountered, but intermittently repeated difficulties with single-lung ventilation occurred. The resultant dysventilation allowed partial right lung reexpansion, along with increased abdominal pressure. The latter induced an upward ballooning of the right diaphragm with consequent obstruction of the surgical field of view, requiring constant and continuous pressure applied to the thoracic surface of the diaphragm via a metal fan retractor and thus counteracting the increased abdominal pressure. Postoperatively, a large subdiaphragmatic hematoma originating from a bleeding right inferior phrenic artery was diagnosed and required urgent endovascular occlusion. The patient made an uneventful recovery with conservative treatment. A very rare and previously unreported complication—that is, early subdiaphragmatic hematoma after thoracoscopic discectomy—is described here. The authors submit that conversion to an open approach is safer when persistent anesthesia-related complications are encountered in thoracoscopic discectomy.

Retrograde ejaculation following single-level anterior lumbar surgery with or without recombinant human bone morphogenetic protein-2 in 5 randomized controlled trials: clinical article

OBJECT

The aim of this study was to determine the incidence and assess specific risk factors in the postoperative development of retrograde ejaculation (RE) in men treated for degenerative lumbar disc disease at the L4-5 or L5-S1 level with stand-alone anterior interbody implants with or without recombinant human bone morphogenetic protein-2 (rhBMP-2).

METHODS

Patients enrolled in 5 prospective, randomized, multicenter FDA-approved investigational device exemption studies were observed for a minimum of 2 years to assess the rate of RE. Five hundred eight men with symptomatic single-level lumbar degenerative disc disease with up to Grade 1 spondylolisthesis underwent anterior lumbar interbody surgery with stand-alone anterior implants at either L4-5 or L5-S1. All patient self-reported and physician-documented adverse events were recorded over the entire course of follow-up. In the investigational groups, 207 patients were treated with an open surgical procedure using dual paired constructs and rhBMP-2 on an absorbable collagen sponge. The control groups (n = 301) were treated with lumbar fusion cage implants and iliac crest autograft or a metal-on-metal disc arthroplasty device. Multivariate analyses of RE were performed to assess the influence of treatment (rhBMP-2), surgical approach, and treated level. Data were analyzed for each trial individually and for the data pooled from the 5 trials.

RESULTS

Retrograde ejaculation occurred at the highest rates in the earliest clinical trial. Of the 146 men, 6 (4.1%) developed RE postoperatively. In subsequent studies, the rates of RE ranged from 0% to 2.1%. Combining the data from the 5 trials, RE was reported in 7 (3.4%) of the 207 patients who received the rhBMP-2 treatment compared with 5 (1.7%) of the 301 patients who received the autograft or lumbar disc treatment (p = 0.242, Fisher exact test). Cases of RE were reported in 7 (1.6%) of 445 patients who underwent a retroperitoneal spinal exposure; 5 RE cases were reported in 58 patients (8.6%) who underwent a transperitoneal approach. The difference in surgical approaches was significant (p = 0.007, Fisher exact test). There was no difference in the rate of RE based on the lumbar level exposed (p = 0.739). Multivariate analyses were consistent with the conclusions from Fisher exact tests. In the initial rhBMP-2 trial, after adjusting for effects of surgical approach and treated level, the difference in RE between the treatment groups (rhBMP-2 vs autograft or disc arthroplasty) was not significant (p = 0.177); however, the difference in RE between the retroperitoneal and transperitoneal approaches was significant (p = 0.029).

CONCLUSIONS

In these 5 prospective randomized trials involving anterior lumbar interbody surgery, the use of rhBMP-2 was associated with a higher incidence of RE (3.4% vs 1.7%) but did not reach statistical significance. Based on surgical approach, the difference in rates of RE was statistically significant. This study reports on the outcomes of 5 prospective randomized FDA-approved investigational device exemption trials. Registration for studies became law in 2007. Four of these trials were completed before the law went into effect. The registration number for the lumbar disc arthroplasty trial is NCT00635843.

An MRI study of psoas major and abdominal large vessels with respect to the X/DLIF approach

Extreme/direct lateral interbody fusion (X/DLIF) has been used to treat various lumbar diseases. However, it involves risks to injure the lumbar plexus and abdominal large vessels when it gains access to the lumbar spine via lateral approach that passes through the retroperitoneal fat and psoas major muscle. This study was aimed to determine the distribution of psoas major and abdominal large vessels at lumbar intervertebral spaces in order to select an appropriate X/DLIF approach to avoid nerve and large vessels injury. Magnetic resonance imaging scanning on lumbar intervertebral spaces was performed in 48 patients (24 males, 24 females, 54.2 years on average). According to Moro's method, lumbar intervertebral space was divided into six zones A, I, II, III, IV and P. Thickness of psoas major was measured and distribution of abdominal large vessels was surveyed at each zone. The results show vena cava migrate from the right of zone A to the right of zone I at L1/2-L4/5; abdominal aorta was located mostly to the left of zone A at L1/2-L3/4 and divided into bilateral iliac arteries at L4/5; Psoas major was tenuous and dorsal at L1/2 and L2/3, large and ventral at L3/4 and L4/5. Combined with the distribution of nerve roots reported by Moro, X/DLIF approach is safe via zones II-III at L1/2 and L2/3, and via zone II at L3/4. At L4/5, it is safe via zones I-II in left and via zone II in right side, respectively.

Two-year clinical and radiographic success of minimally invasive lateral transpsoas approach for the treatment of degenerative lumbar conditions

Background

The lateral transpsoas approach to interbody fusion is a less disruptive but direct-visualization approach for anterior/anterolateral fusion of the thoracolumbar spine. Several reports have detailed the technique, the safety of the approach, and the short term clinical benefits. However, no published studies to date have reported the long term clinical and radiographic success of the procedure.

Materials and methods

The current study is a retrospective chart review of prospectively collected clinical and radiographic outcomes in 62 patients having undergone the Anterolateral transpsoas procedure at a single institution for anterior column stabilization as treatment for degenerative conditions, including degenerative disk disease, spondylolisthesis, scoliosis, and stenosis. Only patients who were a minimum of 2 years postoperative were included in this evaluation. Clinical outcomes measured included visual analog pain scales (VAS) and Oswestry disability index (ODI). Radiographic outcomes included identification of successful arthrodesis.

Results

Sixty-two patients were treated with lateral interbody fusion between 2003 and December 2006. Twenty-six patients (42%) were single-level, 13 (21%) 2-level, and 23 (37%) 3- or more levels. Forty-five (73%) included supplemental posterior pedicle fixation, 4 (6%) lateral fixation, and 13 (21%) were stand-alone. Pain scores (VAS) decreased significantly from preoperative to 2 years follow-up by 37% (P < .0001). Functional scores (ODI) decreased significantly by 39% from preoperative to 2 years follow-up (P < .0001). Clinical success by ODI-change definition was achieved in 71% of patients. Radiographic success was achieved in 91% of patients, with 1 patient with pseudarthrosis requiring posterior revision.

Conclusion

The lateral transpsoas approach is similar to a traditional anterior lumbar interbody fusion, in that access is obtained through a retroperitoneal, direct-visualization exposure, and a large implant can be placed in the interspace to achieve disk height and alignment correction. The 2 years plus clinical and radiographic success rates are similar to or better than those reported for traditional anterior and posterior approach procedures, which, coupled with significant short-term benefits of minimal morbidity, make the lateral approach a safe and effective treatment option for anterior/anterolateral lumbar fusions.

Design and finite-element evaluation of a versatile assembled lumbar interbody fusion cage

INTRODUCTION

When an interbody cage is inserted into a human being's lumbar spine, not only the design, but also the material used is considerably crucial, particularly when minimally invasive lumbar fusion (MILIF) approaches are considered. The purpose of this study was to design a multi-function cage (either for MILIF or open lumbar interbody fusion) and also to evaluate the strength of the design based on a finite-element model analysis.

METHOD

Three-dimensional finite-element models that were instrumental in the reproduction of post-operative conditions under which different cages, such as assembled lumbar interbody fusion cages (ALIFC) and the separated ones, could be examined and traced after implantation were developed. Simulations were run to realize various loading conditions including axial compression, flexion, extension, lateral bending and rotation under a constant compressive preload. Meanwhile, the evaluation results derived from FEMs data focused on endplate stress distribution, peak stress of von Mises and stress of cage. Stress distributions on the bone surface were evaluated and discussed as well.

RESULTS

The consequences of cage insertion, high strains and stresses, were concentrated in the areas where the cage and endplate were in contact with each other. Simultaneously, contact stresses around the implants seemed to be concentrated around the periphery of the device. After implantation of ALIFC, the stiffness of the new cages was similar to that of traditional cages in an assemble condition, according to the biomechanical data dealing with FEM. Once a separated cage was in the place of an assembled cage, the stresses would get symmetrically distributed in the lateral areas of the endplate and decrease significantly at the center where the separated cage was not in contact with the endplate. The stress of the cage was going to be high once being rotating; most significant difference of stresses distribution due to the alternative choice has been found in the state of rotation. On comparison of peak von Mises stresses on the endplates in the new cage, the stresses were symmetrically distributed in the lateral areas of the endplate when a separated cage was used in place of an assembled cage.

CONCLUSION

The new cage was more advantages with regard to endplate stress distribution, peak stress of von Mises and stress of cage than the assembled state. ALIFC can provide sufficient primary stability for lumbar intervertebral fusion and the new cage may be regarded as a suitable device for load-bearing implantation.

Variation in reported safety of lumbar interbody fusion: influence of industrial sponsorship and other study characteristics

STUDY DESIGN

Systematic review.

OBJECTIVE

To quantify variability in undesirable outcomes among studies of lumbar interbody fusion using stand-alone cage devices, and to determine whether author conflicts of interest contribute to variability.

SUMMARY OF BACKGROUND DATA

Promising early studies of lumbar fusion with stand-alone cage devices led to rapid uptake of the technique, but some surgeons later expressed reservations regarding efficacy and safety.

METHODS

We systematically identified studies of lumbar interbody fusion with stand-alone cage devices that reported at least one undesirable outcome among 10 or more adult subjects. We performed meta-analyses of rates of 7 prespecified outcomes (nonunion, reoperation, major vessel injury, retrograde ejaculation, neurologic injury, dural injury, and infection). Heterogeneity in outcome rates was quantified as I2 (the proportion of variance due to differences among studies rather than random variation). Random-effects meta-regression identified sources of observed heterogeneity, including potential conflicts of interest.

RESULTS

We identified 30 eligible studies, including a total of 3228 subjects. A potential conflict of interest was identified in 18 (60%). We observed marked heterogeneity in rates of nonunion, reoperation, and neurologic injury (I2 > 85%; P < 0.001), and substantial heterogeneity in rates of dural injury (I2 = 63%; P < 0.01) and major vessel injury (I2 = 38%; P = 0.09). Among 24 studies reporting fusion status after 6 months of follow-up, nonunion rates ranged from 2.3% to 83.3% (median, 8.3%) and exceeded 45% in 4 studies. Potential author conflict of interest was associated with significantly lower rates of nonunion (P = 0.001). Heterogeneity in rates of other undesirable outcomes was not significantly associated with author conflicts of interest or other study characteristics.

CONCLUSION

We quantified substantial unexplained variation in reported complication rates of undesirable outcomes of lumbar interbody fusion with stand-alone cage devices. Authors with potential conflicts of interest, however, reported significantly lower rates of nonunion.

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.

Laparoscopic approach for lumbar spinal fusion

Several recent articles suggest that utilization of the laparoscopic anterior lumbar interbody fusion (ALIF) is decreasing in this country. After reviewing the published evidence in support and in opposition to this approach, we felt that the topic warranted additional study. We began a prospective study utilizing the known techniques to help reduce serious complications. These techniques were previously reported but not widely utilized according to the available literature. We report our early results of eleven patients along with a detailed description of the approach itself with the emphasis aimed at the laparoscopic approach surgeon. One patient was converted to open, with adequate exposure achieved in all. No bleeding complications were seen. Early postoperative results are encouraging. Our conclusions are that the laparoscopic anterior approach to the lumbar spine can be safely performed by approach-surgeons skilled in advanced laparoscopic techniques and those who have also received additional training in laparoscopic anterior lumbar exposures. We feel that improvement over the open approach may be achievable with increased experience.

Extreme Lateral Interbody Fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion

BACKGROUND

Minimally disruptive approaches to the anterior lumbar spine continue to evolve in a quest to reduce approach-related morbidity. A lateral retroperitoneal, trans-psoas approach to the anterior disc space allows for complete discectomy, distraction, and interbody fusion without the need for an approach surgeon.

PURPOSE

To demonstrate the feasibility of a minimally disruptive lateral retroperitoneal approach and the advantages to patient recovery.

METHODS/RESULTS

The extreme lateral approach (Extreme Lateral Interbody Fusion [XLIF]) is described in a step-wise manner. There have been no complications thus far in the author's first 13 patients.

CONCLUSIONS

The XLIF approach allows for anterior access to the disc space without an approach surgeon or the complications of an anterior intra-abdominal procedure. Longer-term follow-up and data analysis are under way, but initial findings are encouraging.

Minimally disruptive decompression and transforaminal lumbar interbody fusion

BACKGROUND

Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF).

PURPOSE

To evaluate the advantages to patient recovery and surgical efficacy of this technique.

METHODS/RESULTS

Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF).

CONCLUSIONS

Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery.

Neuroendoscopy for spinal disorders: a brief review

Neuroendoscopy has grown rapidly in the last 20 years as a therapeutic modality for treating a variety of spinal disorders. Spinal endoscopy has been widely used to treat patients with cervical, thoracic, and lumbosacral disorders safely and effectively. Although it is most commonly used with minimally invasive lumbar spine surgery, endoscopy has gained widespread acceptance for the treatment of thoracic disc herniations and for anterior release and rod implantation in the correction of thoracic spinal deformity. The authors review the use of endoscopy in spine surgery and in the treatment of spinal disorders as well as in the treatment of intrathoracic nonspinal lesions. Endoscopy has some significant advantages over open or other minimally invasive techniques in that it can allow for better visualization of the lesion, smaller incision sizes with reduced morbidity and mortality, reduced hospital stays, and ultimately lower cost. In addition, spinal endoscopy allows observers and operating room staff to be more involved in each case and fosters education. Spinal endoscopy, like any novel modality, carries with it additional risks and the surgeon must always be prepared to convert to an open procedure. The learning curve for spinal endoscopy is steep and the procedure should not be attempted alone by a novice surgeon. Nevertheless, with training and experience, the spine surgeon can achieve better outcomes, reduced morbidity, and better cosmesis with spinal endoscopy, and the operating times are comparable to open procedures. As technology evolves and more experience is obtained, neuroendoscopy will likely achieve further roles as a mainstay in spine surgery.

Interkorporelle Metallimplantate („Cages“) bei lumbalen Spondylodesen

Over the last 15 years, interbody metal implants have become commonly used worldwide for lumbar interbody fusion. The so called "cages" are made of metal or absorbable materials. By using different surgical techniques, they can be implanted either regularly or via endoscopy. The published results on surgical techniques using cages for the lumbar spine show, in most cases and with or without additional instrumentation, rates of fusion of more than 90%. It seems that the use of osteoinductive substances (especially BMP) leads to even better results. Dorsoventral fusion with internal fixation and bone show the same rate of consolidation, but the advantages of cages are primarily in the maintenance of the distraction and the possibility of a single surgical procedure without additional instrumentation (including endoscopy), and in a lower donor side morbidity.

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

Minimal access surgical techniques have been described for diskectomy and laminectomy procedures performed through tubular exposures. Tubular exposures, however, restrain visibility to a fixed diameter and require co-axial instrument manipulation. An independent blade retractor system has been developed to overcome the obstacles of working through a tube. Decompression and circumferential fusion can be accomplished through this minimal access exposure via a combination of laminectomy and transforaminal lumbar interbody fusion (TLIF) coupled with minimally invasive pedicle screw fixation. Herein, we describe a minimally-invasive technique for TLIF exposure. Illustrations, intraoperative photographs, and fluoroscopic images supplement this technique. We found that the described minimally-invasive system provides comparable exposure to the traditional-open techniques with the benefits of minimally-invasive techniques. Additionally, it does not have the added constraints of a tubular system. We were able to perform TLIFs without any additional complications. Minimal access decompression and TLIF can be performed safely and effectively using this minimally-invasive system. Besides the retractor system, no additional specialized instruments are required. An operative microscope is not required, in fact, all our cases were performed using operative loupes. The light attachment provides superb visbility without the discomfort of having to wear a headlight. Thus far we have found no added risks or complications using this system. We are currently working on long-term analysis and follow-up to further evaluate this system's efficacy.

Comparative study of laparoscopic L5-S1 fusion versus open mini-ALIF, with a minimum 2-year follow-up

Anterior lumbar interbody fusion (ALIF) is a widely accepted tool for management of painful degenerative disc disease. Recently, the modern laparoscopic surgical technique has been combined with ALIF procedure, with good early postoperative results being reported. However, the benefit of laparoscopic fusion is poorly defined compared with its open counterpart. This study aimed to compare perioperative parameters and minimum 2-year follow-up outcome for laparoscopic and open anterior surgical approach for L5-S1 fusion. The data of 54 consecutive patients who underwent anterior lumbar interbody fusion (ALIF) of L5-S1 from 1997 to 1999 were collected prospectively. More than 2-years' follow-up data were available for 47 of these patients. In all cases, carbon cage and autologous bone graft were used for fusion. Twenty-five patients underwent a laparoscopic procedure and 22 an open mini-ALIF. Three laparoscopic procedures were converted to open ones. For perioperative parameters only, the operative time was statistically different (P=0.001), while length of postoperative hospital stay and blood loss were not. The incidence of operative complications was three in the laparoscopic group and two in the open mini-ALIF group. After a follow-up period of at least 2 years, the two groups showed no statistical difference in pain, measured by visual analog scale, in the Oswestry Disability Index or in the Patient Satisfaction Index. The fusion rate was 91% in both groups. The laparoscopic ALIF for L5-S1 showed similar clinical and radiological outcome when compared with open mini-ALIF, but significant advantages were not identified, despite its technical difficulty.

Adapting innovative motion-preserving technology to spinal surgical practice: what should we expect to happen?

STUDY DESIGN

A literature-based review of approach-related morbidity and a conjectural analysis of potential complications of disc arthroplasty based on experience with total joint arthroplasty.

OBJECTIVE

To describe predictable complications of disc arthroplasty and possible strategies for minimizing or treating these complications.

SUMMARY OF BACKGROUND DATA

There is a significant experience with anterior approach-related morbidity in spinal surgery. There is also extensive experience with extremity total joint arthroplasty. The combination of these experiences should predict certain occurrences that will occur with the advent of disc arthroplasty in the spine.

METHODS

Review of the medical literature associated with anterior approach to the lumbar spine for spinal fusion was done. Sequential steps for performance of disc arthroplasty and possible problems with each step were evaluated and possible complications identified. Parallel experience in total joint arthroplasty was reviewed for possible predictive experience.

RESULTS

There are definable approach-related morbidities that will occur, regardless of prosthesis design and implantation technique. Prosthesis design involves a series of tradeoffs for risks and benefits. Revisions are inevitable; rate of revision and time to revision remain to be determined.

CONCLUSIONS

Disc arthroplasty will offer benefits over current fusion techniques. It will come at a cost and certain complications are entirely predictable. There will be deaths from the procedure, due to thromboembolic phenomenon or due to uncontrollable hemorrhage from irreparable vascular injury, especially on repeat operations. There will be prostheses that dislodge. There will be infections that require device removal, a very high-risk procedure. There will be a deterioration of results in the hands of the general medical community as opposed to the hands of the initial investigators, a learning curve if you will. The access surgeon will be critical to minimizing morbidity. Design considerations compete with anatomic constraints. Material choices all have pros and cons. Spine surgeons as a whole are excited about this opportunity, but we must be diligent to minimize these predictable adverse events to make the risk benefit profile the best that it can be for our patients.

Interbody cage devices

STUDY DESIGN

A literature review was conducted of basic science research and clinical experiences describing the use of interbody cage devices for the management of degenerative spinal abnormalities.

OBJECTIVES

To summarize current knowledge regarding the use of interbody fusion cages.

SUMMARY OF BACKGROUND DATA

Degenerative conditions of the lumbar and cervical spine are a major societal expense and a leading cause of disability. Fusion surgery may be used to treat patients with some of these conditions. During the past decade, interbody cages have been popularized as a useful fusion technique with high rates of clinical and radiographic success reported. Cages may be implanted using a variety of surgical approaches to the disc space and can be used alone or with supplemental posterior fixation.

METHODS

A literature review of biomechanical, biologic, and clinical studies of threaded interbody cages was performed.

RESULTS

Interbody cages have been shown to successfully promote fusion in a variety of animal models. In biomechanical studies, anteriorly placed threaded cages significantly stabilize the motion segment in all directions except extension. Posteriorly placed cages provide less stability as a result of the facetectomy required for placement of an appropriately sized device. Successful clinical and radiographic results have been reported with the use of interbody cages. Most reported cage failures are the result of technical difficulties with implantation or poor patient selection. Accurate radiographic assessment of fusion in the presence of a metal interbody cage remains challenging, and studies evaluating alternate biomaterial cages are underway.

CONCLUSION

Interbody cages are a useful technique for achieving spinal fusion and have been shown to have an acceptable clinical success rate in appropriately selected patients.

Video-assisted versus open anterior lumbar spine fusion surgery: a comparison of four techniques and complications in 135 patients

STUDY DESIGN

A retrospective review involved 135 patients undergoing anterior interbody fusion using four different approaches: transperitoneal video-assisted surgery with insufflation, retroperitoneal endoscopic video-assisted surgery, minilaparotomy retroperitoneal surgery, and traditional oblique muscle-splinting retroperitoneal surgery.

OBJECTIVE

To describe and compare the operative procedure and perioperative complications of four different interbody fusion techniques.

SUMMARY OF BACKGROUND DATA

Although anterior lumbar interbody fusion surgery has a long history, several new and innovative approaches have been introduced recently. In contrast to the traditional oblique muscle-splitting retroperitoneal flank incision, the following have been used: a "minilaparotomy" open extraperitoneal approach through a small midline incision, a transperitoneal video-assisted insufflation technique, and a video-assisted gasless retroperitoneal endoscopic technique.

METHODS

A retrospective review was performed using the hospital records, operating room records, and clinic charts of 135 consecutive patients (50 men and 85 women) who underwent surgery between December 1993 and February 1998. Cases were included if either bone grafts alone or cylindrical cages with bone graft inside were used. Cases with anterior instrumentation using plates or rods were excluded. Diagnoses included degenerative disc disease, spondylolisthesis, or pseudarthrosis of a previous lumbosacral fusion. Patients with tumors or infection were excluded. The patients all were adults ranging in age from 17 to 83 years. Among the 135 patients, 12 had undergone previous anterior spine fusion surgery and 64 had undergone prior abdominal surgery.

RESULTS

The onset of new radicular pain or numbness, not experienced by the patient before surgery, occurred in six patients (18%; all with transperitoneal video-assisted surgery using insufflation). Vascular problems occurred in five patients (3.7% overall): two in the transperitoneal video-assisted group (5.9% of the group) and three in the minilaparotomy group (8.7% of the group). Retrograde ejaculation occurred in 4 of the 50 male patients (8% of the group): three in the transperitoneal video-assisted group (25% of the group) and one in the minilaparotomy group (2% of the group). Two patients had ureteral injuries (1.5% overall): one each in the retroperitoneal endoscopic and minilaparotomy groups. Conversion to open procedures was performed in seven patients (11% of the video-assisted procedures). The reasons for conversion included two major vessel lacerations and five peritoneal tears in the retroperitoneal video-assisted group.

CONCLUSIONS

A comparative analysis of four techniques for approaching the lower lumbar spine to perform arthrodesis in 135 patients showed an incidence of complications consistent with the literature for video-assisted techniques, but higher than for open techniques. For these and other reasons, the video-assisted approaches have been abandoned by the surgeons of this report.

Is Laparoscopic Anterior Lumbar Interbody Fusion a Useful Minimally Invasive Procedure?

OBJECTIVE

Laparoscopic anterior lumbar interbody fusion (LALIF) has been demonstrated to be safe and effective. Its use as a standard surgical technique has been recommended for arthrodesis in the lumbosacral region. We reviewed our experience with LALIF for safety, effectiveness, and usefulness.

METHODS

Retrospective review of 14 patients who underwent LALIF was performed. All patients had a diagnosis of degenerative disc disease with medically retractable mechanical back pain.

RESULTS

No intraoperative vascular or neurological injury was encountered. An average operating time of 300 minutes with blood loss of 60 ml was found. The average hospital stay was 3.4 days. At 3 to 6 months after surgery, 80% fusion rates were achieved.

CONCLUSION

Although LALIF is a safe and effective procedure, it has many disadvantages, which make it a less than optimal procedure for routine use. Other minimally invasive approaches to the anterior lumbar spine result in similar beneficial results without the drawbacks associated with LALIF.

Review: Complications of Minimally Invasive Spinal Surgery

COMPLICATIONS OF MINIMALLY invasive spinal surgery can be related to anesthesia, patient positioning, and surgical technique. The performance of successful minimally invasive spinal surgery is beset with several technical challenges, including the limited tactile feedback, two-dimensional video image quality of three-dimensional anatomy, and the manual dexterity needed to manipulate instruments through small working channels, which all account for a very steep learning curve. Knowledge of possible complications associated with particular minimally invasive spinal procedures can aid in their avoidance. This article reviews complications associated with minimally invasive spinal surgery in the cervical, thoracic, and lumbar spine by reviewing reported data of sufficient detail or with sufficient numbers of patients. In addition, possible complications associated with anesthesia use, patient positioning, and surgical techniques during thoracoscopic and laparoscopic spinal procedures are reviewed.

Anterior Access to the Lumbar Spine: Laparoscopic versus Open

The purpose of this study is to investigate the potential advantages and complications of a minimally invasive laparoscopic approach for anterior spinal exposure as compared with the open technique and to quantify differences in operative time, blood loss, transfusion requirements, analgesia, and morbidity. A retrospective review was performed on all patients undergoing access for anterior spinal procedures. Demographics, operation-related variables, complications, and estimated cost were analyzed. Categorical data were analyzed using the Fisher's exact test and continuous variables were analyzed with the Mann-Whitney U test. We performed a total of 65 anterior spinal access procedures between February 1997 and April 2001 at our institution. Forty-five operations were performed at the L5-S1 level: 31 using transperitoneal laparoscopic techniques and 14 using an open minilaparotomy. Mean follow-up was 12 months (range 1–50). No significant differences between the groups were found when comparing analgesia requirements, time to resumption of oral intake, length of hospitalization, and complication rates. Statistical analysis showed that laparoscopic procedures were associated with shorter operating room times ( P = 0.08) and less intraoperative blood loss ( P = 0.029). The laparoscopic approach was estimated to cost $1,374 more than the open technique. Transperitoneal laparoscopic techniques for anterior spinal exposure are comparable to the standard open approach and offer no substantive advantages. The overall cost of laparoscopic spinal surgery is higher compared with conventional open procedures.

Laparoscopic anterior lumbar interbody fusion at L4-L5: an anatomic evaluation and approach classification

STUDY DESIGN

An anatomic classification system was devised on the basis of operative reports and preoperative magnetic resonance imaging or computerized tomography from 139 patients who underwent laparoscopic anterior lumbar interbody fusion involving L4-L5.

OBJECTIVE

To devise a classification system for laparoscopic exposure of the L4-L5 disc space that would allow prediction of the safest approach for any given vascular configuration.

SUMMARY OF BACKGROUND DATA

The laparoscopic technique has gained acceptance at L5-S1 but has been less successful at L4-L5. The vascular bifurcation and the variability of the anatomy have led to difficulties with exposure.

METHODS

Data were collected on 139 patients undergoing laparoscopic anterior lumbar interbody fusion involving the L4-L5 disc space. Operative notes and preoperative magnetic resonance imaging and computed tomography scans were reviewed, and a classification system was devised based on the aortic bifurcation and confluence of the left iliac vein with the vena cava. Three variations were identified. Complications, particularly ejaculatory dysfunction, were described.

RESULTS

Three classification categories were described. Twenty-five patients (18%) were classified as category A (above the bifurcation of both vessels), 52 patients (37%) were classified as category B (below the bifurcation of both vessels), and 51 patients (37%) were classified as category C (between the left iliac artery and vein). There were 8 (5.8%) intraoperative and 17 (12.2%) postoperative complications. Ejaculatory dysfunction constituted the majority of the postoperative complications, representing 16% of the male population. The incidence of ejaculatory dysfunction correlated with exposure from the left side of the aorta or the left iliac artery. For two-level fusions from L4 to S1, the incidence of ejaculatory dysfunction was 63% for category A but 0% for categories B and C. An alternative approach was suggested for category A: exposing the disc space between the aorta and vena cava.

CONCLUSION

The laparoscopic approach to L4-L5 is complicated by the variability of the vascular anatomy encountered during the exposure. Routine magnetic resonance imaging or computed tomography can be used to classify the vascular anatomy and plan the optimal approach. Avoiding the left side of the aorta or the left iliac artery may minimize the risk of ejaculatory dysfunction.

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.

Laparoscopic anterior lumbar interbody fusion with rhBMP-2: a prospective study of clinical and radiographic outcomes

STUDY DESIGN

To prospectively evaluate the clinical and radiographic outcome of laparoscopic anterior lumbar interbody fusion with rhBMP-2.

OBJECTIVES

It was hypothesized that discogenic pain could be treated successfully with an anterior lumbar interbody fusion performed laparoscopically using rhBMP-2 as a replacement for autogenous bone.

SUMMARY OF BACKGROUND DATA

The traditional surgical treatment of discogenic pain involves painful incisions of muscles, with potential loss of integrity and strength. Harvesting of bone graft is associated with significant complications including persistent pain at the donor site.

METHODS

Twenty-two consecutive patients were studied prospectively with the surgery performed by one surgeon. Patients were evaluated clinically and radiographically at 6 and 12 months after surgery. An unbiased radiologist read postoperative computed tomography scans for evidence of fusion.

RESULTS

There were 8 male (36%) and 14 female (64%) patients. The average age was 38 years (range, 21-56 years). At 6 and 12 months after surgery 95% (21 of 22) were available for follow-up; 100% were satisfied with treatment at 12 months. Concerning their symptoms, 100% reported relief of back pain, 100% had improvement of leg pain, and 100% described significant functional improvement. Improvements were seen at 6 and 12 months on Oswestry (P < 0.001), functional testing (P < 0.001), and pain analog scale (P < 0.001). Radiographic analysis showed that all of the patients had evidence of a solid fusion at 6 months after operation.

CONCLUSION

Discogenic low back pain can be effectively treated surgically with a laparoscopic anterior lumbar interbody fusion using rhBMP-2 in place of autogenous bone. The fusion occurs quickly and predictably with no adverse effects identified.