Vertebral osteolysis originating from subchondral cyst end plate defects in transforaminal lumbar interbody fusion using rhBMP-2. Report of two cases

Background ContextVertebral osteolysis has been reported as a complication of off-label recombinant human bone morphogenetic protein-2 (rhBMP-2) use in transforaminal lumbar interbody fusion (TLIF). It has been postulated that end plate violation during disc space preparation, rhBMP-2 overdosing, or a combination thereof can contribute to the development of vertebral osteolysis when rhBMP-2 is used in the lumbar interspace.PurposeTo present two cases of vertebral osteolysis that occurred after TLIF in which rhBMP-2 was used. In each case, the osteolysis originated from subchondral cysts that were present on preoperative computed tomographic (CT) scans.Study DesignCase report.MethodsTwo patients underwent instrumented TLIF using INFUSE (Medtronic, Inc., Littleton, MA, USA) on an absorbable collagen sponge carrier. In each patient, approximately 4 mg of rhBMP-2 was placed anteriorly in the disc space with 0.1 mg of rhBMP-2 being placed inside a polyetheretherketone interbody cage. Morcellized allograft bone mixed with demineralized bone matrix was also placed in the disc space and cage. The remaining rhBMP-2 was placed posterolaterally on the contralateral side. Each patient presented with worsening back pain approximately 3 to 4 months postoperatively and CT scans revealed osteolysis affecting the L4 and L5 vertebral bodies. The osteolysis appeared to originate from preoperative vertebral defects caused by subchondral cysts.ResultsOne patient underwent removal of the interbody cage at the L4–L5 level and revision of the fusion with iliac crest autograft. At 15-month follow-up, he had no complaints of back pain, and CT scanning revealed solid fusion across the L4–L5 disc space. The other patient was offered revision of his fusion but declined any further surgery. At 2-year follow-up, that patient had persistent back pain but still declined any further surgery. A CT scan revealed unchanged osteolysis at the L4 and L5 levels.ConclusionsIt has been proposed that rhBMP-2-induced vertebral osteolysis occurring in TLIF procedures may be secondary to end plate violation during disc preparation or overdosing of rhBMP-2. Although overdosing may have also contributed to vertebral osteolysis in our two cases, the end plate violation from subchondral cyst formation that was present on preoperative CT scans seemed to be the origin of the osteolysis suggesting that the presence of preoperative subchondral cysts may be an additional risk factor for development of osteolysis in these patients.     

Vertebral bone resorption after transforaminal lumbar interbody fusion with bone morphogenetic protein (rhBMP-2)

OBJECTIVE: Bone morphogenetic protein (rhBMP-2) has demonstrated an increased rate of interbody fusion when placed in the intervertebral space. Owing to this advantage, rhBMP-2 is being implanted with increasing frequency in the lumbar spine. The purpose was to quantify and describe the presence of bone resorption within the vertebral body after transforaminal lumbar interbody fusion with placement of rhBMP-2 within the disc space. METHODS: Twenty-six patients were selected from a clinical database. Patients included in the study had undergone a transforaminal lumbar interbody fusion with BMP. Interbody implants included allograft dowels or interbody cages augmented with autograft or allograft bone. A computed tomography study of the lumbar spine a minimum of 3-month postoperatively was another inclusion criterion. Osteolytic defects were grouped into 3 categories on the basis of the size and extent of involvement in the vertebral body. RESULTS: A total of 32 lumbar levels were reviewed. Fourteen males and 12 females with an average age of 46.0 years were included in the study. Bone resorption defects were noted in 22 of the 32 levels reviewed (69%). The defects were characterized as mild in 50% (11 of 22), moderate in 18% (4 of 22), and severe in 31% (7 of 22). CONCLUSIONS: The benefit of rhBMP-2 to promote interbody fusion in the lumbar spine has been well documented. BMP has demonstrated an increased fusion rate and the ability to produce a robust fusion mass. rh-BMP-2's osseous remodeling potential may lead to bone resorption within the vertebral body.     

Comparison of posterior and transforaminal approaches to lumbar interbody fusion

STUDY DESIGN: A study of the transforaminal lumbar interbody fusion and the posterior lumbar interbody fusion techniques was performed. OBJECTIVES: To describe the transforaminal lumbar interbody fusion technique, and to compare operative data, including blood loss and operative time, with data from posterior lumbar interbody fusion technique. SUMMARY OF BACKGROUND DATA: The evolution of posterior lumbar fusion combined with anterior interbody fusion has resulted in increased fusion rates as well as improved reductions and stability. The transforaminal lumbar interbody fusion technique pioneered by Harms and Jeszensky offers potential advantages and provides a surgical alternative to more traditional methods. METHODS: In 13 consecutive months, two spinal surgeons performed 40 transforaminal lumbar interbody fusions and 34 posterior lumbar interbody fusion procedures. Data regarding blood loss, operative times, and length of hospital stay were recorded. These data were analyzed using analysis of variance to show any significant differences between the two techniques. To determine whether differences in measured variables were dependent on patient gender or number of levels fused, epsilon(chi2) analysis was used. RESULTS: No significant differences were found between transforaminal and posterior lumbar interbody fusions in terms of blood loss, operative time, or duration of hospital stay when a single-level fusion was performed. Significantly less blood loss occurred when a two-level fusion was performed using the transforaminal approach instead of the posterior approach (P < 0.01). Differences in measured variables for the two procedures were independent of patient age, gender, and the number of levels fused. There were no complications with the transforaminal approach, but the posterior approach resulted in multiple complications. CONCLUSIONS: In this comparison of patients receiving transforaminal lumbar interbody fusion versus posterior lumbar interbody fusion, no complications occurred with the transforaminal approach, whereas multiple complications were associated with the posterior approach. Similar operative times, blood loss, and duration of hospital stay were obtained in single-level fusions, but significantly less blood loss occurred with the transforaminal lumbar interbody approach in two-level fusions. The transforaminal procedure preserves the interspinous ligaments of the lumbar spine and preserves the contralateral laminar surface as an additional surface for bone graft. It may be performed at all lumbar levels because it avoids significant retraction of the dura and conus medullaris.     

微创经椎间孔腰椎间融合术治疗高位腰椎间盘突出症

目的评价微创经椎间孔入路腰椎间融合术（MIS-TLIF）治疗高位腰椎间盘突出症的中短期临床疗效。方法对自2009-01—2012—12收治的高位腰椎间盘突出症22例行MIS—TLIF术,根据患者症状、体征及影像学资料,切除单侧减压、对侧潜行减压或两侧开窗减压,并行自体及同种异体骨椎间植骨、椎间融合器融合、经皮椎弓根钉内固定。结果所有患者获平均（12±3）个月的随访,出现椎间植骨不融合1例,椎间植骨融合时间为（7．2±1．3）个月。术后下肢放射痛VAS评分及腰背痛ODI评分与术前比较,差异有统计学意义（P〈0．05）。改良MacNab标准评价优良率为86．4％。结论MIS-TLIF治疗高位腰椎间盘突出症是安全、有效的方法。     

Osteolysis in transforaminal lumbar interbody fusion with bone morphogenetic protein-2

STUDY DESIGN.: Retrospective radiographic review. OBJECTIVE.: To determine the incidence of osteolysis, graft subsidence, and cage migration after recombinant human bone morphogenetic protein-2 (rhBMP-2) use with transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA.: Osteolysis after TLIF is a recently described phenomenon associated with rhBMP-2 use. Although this is typically a self-limiting condition, complications such as graft subsidence and cage migration have been described. The incidence of this is not well defined and most studies use plain radiographs for diagnosis rather than more advanced imaging. This study serves to quantify the risk of osteolysis and its associated graft complications with routine use of computed tomography. METHODS.: A total of 58 patients who underwent primary TLIF from a single surgeon between 2004 and 2007 underwent routine postoperative computed tomographic scan. Seventy-seven levels of fusion were evaluated for osteolysis. All patients received the same dose of rhBMP-2 of 5 mg per level. Imaging was performed immediately postoperative and again at an average of 4.3 months postoperative (range = 2.4-9.0 months). These images were evaluated for the presence of osteolysis, graft subsidence, and cage migration. These changes were then graded according to their severity. RESULTS.: Osteolysis was found in 16 of the 58 (27.6%) patients and 19 of the 77 (24.7%) levels treated. No significant difference was found between single and two-level fusions. The degree of osteolysis ranged from 3 to 20 mm with an average of 12.5 mm. The osteolysis was characterized as severe (>1 cm) in 12 of the 19 levels. Of the patients with osteolysis, 31.6% demonstrated graft subsidence all of which occurred with severe osteolytic defects. Migration of the intervertebral cage was found in 8.8% of patients. CONCLUSION.: rhBMP-2 use with TLIF is associated with a significant risk of postoperative osteolysis. Patients who demonstrated postoperative osteolysis were associated with significant risk of subsidence or migration of the intervertebral cage. The clinical implications of these changes are not currently known.     

Early retropulsion of titanium-threaded cages after posterior lumbar interbody fusion: a report of two cases

STUDY DESIGN: Two patients had postoperative posterior migration of titanium fusion cages after posterior lumbar interbody fusion. They underwent a repeat posterior procedure and posterior fusion with pedicle screws. OBJECTIVE: To suggest a treatment for posterior migration of titanium-threaded cages causing spinal stenosis after posterior lumbar interbody fusion. SUMMARY OF BACKGROUND DATA: The use of titanium fusion cages in posterior lumbar interbody fusion is gaining popularity as a technique for arthrodesis. The literature contains only a few reports concerning complications associated with their use. METHODS: Two patients had retropulsion of titanium threaded cages, ten days and 2 months after posterior lumbar interbody fusion. The retropulsed cages compressing the dura, caused sudden onset of back pain and radiating pain to the lower extremities. Both patients underwent repeat posterior procedure that included repositioning of the cages and posterior fusion with pedicle screws. RESULTS: Symptoms of back and leg pain subsided after repositioning of the cages and application of the pedicle screws. CONCLUSIONS: A repeat posterior approach and repositioning of the retropulsed titanium fusion cages in addition to posterior fusion with pedicle screws successfully managed this complication.     

后路椎间植骨椎弓根螺钉固定治疗椎间盘源性腰痛

目的研究后路椎体间融合加椎弓根固定治疗腰椎间盘源性腰痛的手术疗效。方法 35例腰椎间盘源性下腰痛,选择后路椎体间植骨融合（posterior lumbar interbody fusion,PLIF）加椎弓根螺钉系统内固定术。分别于术前、术后对患者的腰痛情况进行JOA评分,同时评估术后腰椎融合率。结果术后随访时间8～24个月,平均18个月。术后腰部疼痛症状缓解明显,优21例,良8例,一般4例,差2例,有效率95%。术后椎间植骨临床愈合35例,植骨愈合有效率100%。结论后路椎间植骨椎弓根螺钉固定术对椎间盘源性腰痛是一种有效的治疗方法。     

椎弓根固定结合经椎间孔椎间融合治疗复发性腰椎间盘突出症伴腰椎不稳

目的：探讨经肌间隙入路椎弓根固定结合经椎间孔椎间融合（transforaminal lumbar interbody fusion,TLIF）治疗复发性腰椎间盘突出症伴腰椎不稳的临床疗效。方法：2008年3月至2010年5月收治35例复发性腰椎间盘突出症,其中15例行经肌间隙入路单边椎弓根固定结合TLIF术式（单边固定组）,20例行后正中入路双边椎弓根固定结合后路椎间植骨融合（posterior lumbar interbody fusion,PLIF）术式（双边固定组）.观察手术时间、术中出血量,并比较手术前后两组患者JOA评分、腰痛及腿痛VAS评分及融合情况。结果：所有患者获得随访,时间6～30个月,平均16.8个月。两组患者腰腿痛等临床症状较术前明显缓解,X线片显示植骨融合良好（双边固定组中1例未融合）,无融合器移位、下沉及内固定器械松动或断裂。两组患者手术时间、术中出血量比较差异有统计学意义（P<0.05）.术后JOA评分均较术前降低（P<0.05）.术后1周,两组患者腰痛VAS评分比较差异有统计学意义（P<0.05）,腿痛VAS评分比较差异无统计学意义（P>0.05）;末次随访,腰痛及腿痛VAS评分两组比较差异无统计学意义（P>0.05）.结论：两种术式在治疗复发性腰椎间盘突出症伴腰椎不稳均可达到满意的疗效,经肌间隙入路单边椎弓根固定结合TLIF术式切口较小,手术时间较短,术中出血量较少,术后腰痛缓解较快。     

Transforaminal lumbar interbody fusion: technique, complications, and early results

OBJECTIVE: To demonstrate the safety, surgical efficacy, and advantages of the transforaminal approach for lumbar interbody fusion when combined with pedicle screw fixation. METHODS: We retrospectively reviewed the records of 22 patients (age range, 34-63 yr; mean, 49 yr) with Grade I or II spondylolisthesis who underwent transforaminal lumbar interbody fusion. Nineteen patients presented with low back pain and associated radiculopathy, and three presented with low back pain only. Transforaminal lumbar interbody fusion was performed at L4-L5 in 8 patients, L5-S1 in 11 patients, L3-L4 and L4-L5 in 2 patients, and L4-L5 and L5-S1 in 1 patient. Periodic follow-up took place 1 to 12 months after surgery (mean, 5.3 mo). Decompression is performed according to clinical circumstances. Pedicle screws are placed, and a discectomy is carried out. The cartilaginous endplates are removed. The interspace is gradually distracted, resulting in lost disc height being regained, and interbody fusion cages are positioned. The pedicle screw-and-rod construct is then compressed, restoring lumbar lordosis. RESULTS: Low back pain completely resolved in 16 patients, moderate relief from pain was achieved in 5 patients, and the pain was unchanged in one patient. Nonneurological complications included intraoperative durotomy in one patient and postoperative wound infection in two. In one patient, postoperative mild L5 motor paresis resolved. One patient had a temporary brachial plexopathy due to intraoperative positioning, and one patient had peripheral polyneuropathy secondary to prolonged intraoperative blood pressure cuff inflation. CONCLUSION: Transforaminal lumbar interbody fusion is a safe and effective method for achieving circumferential spinal fusion via a single-stage procedure. This procedure is particularly useful in restoring disc space height and lumbar lordosis.     

椎问隙狭窄型峡部裂性腰椎滑脱的手术治疗

目的探讨椎间隙狭窄型峡部裂性腰椎滑脱的手术方法及临床疗效。方法对30例椎间隙狭窄型峡部裂性腰椎滑脱患者采用钉棒系统内固定加经椎间孔椎体间融合器结合打压植骨融合（TLIF）术进行治疗。结果随访12—18个月,所有患者腰腿痛症状均消失,植骨融合率100％,4例患者残留部分下肢麻木症状。结论钉棒系统内固定加经椎间孔椎体间融合器结合打压植骨融合（TLIF）术可达到恢复椎间隙高度、神经根孔间接减压、椎管减压、重建脊柱的生理曲度和脊柱的稳定性的效果,是一种可靠、有效的方法。     

Transforaminal lumbar interbody fusion: a retrospective study of long-term pain relief and fusion outcomes

No long-term studies exist on the effectiveness of transforaminal lumbar interbody fusion. This study sought to determine postoperative pain, disability, and fusion status of transforaminal lumbar interbody fusion patients after > or = 4 years to establish long-term outcomes. A retrospective analysis of 42 patients with minimum 4-year follow-up was conducted. Patients completed visual analog pain scale (VAS) and Oswestry functional capacity evaluation pre- and postoperatively. Statistically significant improvement was noted in VAS and Oswestry functional capacity evaluation scores. Transforaminal lumbar interbody fusion is effective in alleviating intractable back pain over an extended time period. Solid radiographic fusion is unnecessary for clinically successful outcomes.     

The use of RhBMP-2 in single-level transforaminal lumbar interbody fusion: a clinical and radiographic analysis

The “off label” use of rhBMP-2 in the transforaminal lumbar interbody fusion (TLIF) procedure has become increasingly popular. Although several studies have demonstrated the successful use of rhBMP-2 for this indication, uncertainties remain regarding its safety and efficacy. The purpose of this study is to evaluate the clinical and radiographic outcomes of the single-level TLIF procedure using rhBMP-2. Patients who underwent a single-level TLIF between January 2004 and May 2006 with rhBMP-2 were identified. A retrospective evaluation of these patients included operative report(s), pre- and postoperative medical records, and dynamic and static lumbar radiographs. Patient-reported clinical outcome measures were obtained from a telephone questionnaire and included a modification of the Odom’s criteria, a patient satisfaction score, and back and leg pain numeric rating scale scores. Forty-eight patients met the study criteria and were available for follow-up (avg. radiographic and clinical follow-up of 19.4 and 27.4 months, respectively). Radiographic fusion was achieved in 95.8% of patients. Good to excellent results were achieved in 71% of patients. On most recent clinical follow-up, 83% of patients reported improvement in their symptoms and 84% reported satisfaction with their surgery. Twenty-nine patients (60.4%) reported that they still had some back pain, with an average back pain numeric rating score of 2.8. Twenty patients (41.7%) reported that they still had some leg pain, with an average leg pain numeric rating score was 2.4. Thirteen patients (27.1%) had one or more complications, including transient postoperative radiculitis (8/48), vertebral osteolysis (3/48), nonunion (2/48), and symptomatic ectopic bone formation (1/48). The use of rhBMP-2 in the TLIF procedure produces a high rate of fusion, symptomatic improvement and patient satisfaction. Although its use eliminates the risk of harvesting autograft, rhBMP-2 is associated with other complications that raise concern, including a high rate of postoperative radiculitis.     

微创单侧椎弓根螺钉固定、椎体间融合治疗腰椎疾患所致腰痛的临床观察

目的:评价微创单侧椎弓根螺钉固定、椎间融合治疗腰椎疾患所致腰痛的临床疗效。方法:2003年12月～2006年8月,共收治不同原因所致腰痛患者29例,其中腰椎间盘突出症13例,腰椎不稳8例,椎间盘源性腰痛5例,MED术后复发3例,均采用可扩张管道系统经椎间孔行椎体间植骨融合、单侧椎弓根螺钉固定术治疗。应用视觉模拟评分系统(VAS)评估患者术前、术后疼痛情况,应用Kim方法评价临床效果,应用Schulte方法观察植骨融合情况。结果:1例患者术后出现对侧下肢放射性疼痛,保守治疗无效,再次手术行神经根管减压和内固定后症状缓解。随访21～36个月,平均31.5个月,术前VAS评分为7.7±0.6分,术后3个月时为1.9±0.9分,两者比较有显著性差异(P0.001),术后3个月时Kim优良率为89.7%,末次随访时Kim优良率为96.6%,满意率为96.6%。末次随访时椎间融合率为93.1%,1例可能融合和1例假关节形成。结论:微创单侧椎弓根螺钉固定是治疗腰痛的一种有效方法,但需要严格把握手术适应证。     

经神经根孔入路腰椎融合加椎弓根固定治疗腰椎间盘源性下腰痛

目的研究经神经根孔入路腰椎融合(transforaminal lumbar interbody fusion,TLIF)加椎弓根固定治疗腰椎间盘源性下腰痛的手术疗效。方法26例腰椎间盘源性下腰痛,选择行后路TLIF手术加椎弓根固定治疗。分别于术前、术后对患者的腰痛情况进行VAS评分,同时评估术后腰椎融合率。结果术后随访时间8~24个月,平均16个月。25例术后腰腿痛症状基本消失,1例仍有轻度腰痛,融合率为100%。结论严格掌握手术适应证,后路腰椎椎体间融合术是治疗腰椎间盘源性下腰痛的有效方法。     

扩张式椎间融合器在腰椎融合术中的应用

目的探讨扩张式椎间融合器（expanding cage,EC）在腰椎融合术中应用的适应性、技术要点和疗效。方法本组47例患者,均行后路扩张式椎间融合术（PELIC）。术前分别诊断为腰椎管狭窄、腰椎间盘突出、腰椎滑脱和退变性腰椎不稳,经非手术治疗无效后,以手术对椎管及神经根管减压,用EC融合固定并植骨。术前、术后对患者的腰疼情况进行视觉痛觉自我评定尺（VAS）评分。结果所有患者术前症状消失,术中未发生神经损伤,随访最长时间为61个月,最短53个月,平均57．3个月,无假关节形成,无明显椎体塌陷。结论EC在腰椎融合术应用中具有融合可靠、症状改善明显等优点。     

Transforaminal lumbar interbody fusion using unilateral pedicle screws and a translaminar screw

Lumbar spinal fusion is advancing with minimally invasive techniques, bone graft alternatives, and new implants. This has resulted in significant reductions of operative time, duration of hospitalization, and higher success in fusion rates. However, costs have increased as many new technologies are expensive. This study was carried out to investigate the clinical outcomes and fusion rates of a low implant load construct of unilateral pedicle screws and a translaminar screw in transforaminal lumbar interbody fusion (TLIF) which reduced the cost of the posterior implants by almost 50%. Nineteen consecutive patients who underwent single level TLIF with this construct were included in the study. Sixteen patients had a TLIF allograft interbody spacer placed, while in three a polyetheretherketone (PEEK) cage was used. Follow-up ranged from 15 to 54 months with a mean of 32 months. A clinical and radiographic evaluation was carried out preoperatively and at multiple time points following surgery. An overall improvement in Oswestry scores and visual analogue scales for leg and back pain (VAS) was observed. Three patients underwent revision surgery due to recurrence of back pain. All patients showed radiographic evidence of fusion from 9 to 26 months (mean 19) following surgery. This study suggests that unilateral pedicle screws and a contralateral translaminar screw are a cheaper and viable option for single level lumbar fusion.     

后路减压联合经腰椎间孔椎体间融合术60例临床分析

目的探讨后路减压联合经椎间孔腰椎体间融合术（TLIF）治疗腰椎退行性疾病的疗效。方法采用椎管扩大减压后行TLIF手术,使用单枚融合器加椎弓根钉治疗腰椎退行性疾病60例。结果 60例均获随访,时间8～30个月。无椎弓根钉失败及Cage前、后侧移位。3例术后出现无症状侧下肢麻木、酸痛感,于1～3个月症状消除。疗效：优38例,良19例,可3例,优良率为95%。结论采用单枚融合器及扩大减压可增加TLIF手术适应证且临床疗效满意,但术中应注意无症状侧的选择性减压及融合器型号的选择。     

经椎间孔入路腰椎体间融合内固定术的临床研究

目的：探讨经椎间孔入路腰椎体间融合内固定术的疗效。方法：回顾经椎间孔入路腰椎体间融合内固定术40例,共融合49个节段。分析比较术前及术后1年患者椎体间高度、角度、ODI、VAS评价、融合情况和并发症。结果：所有病例获随访,平均18个月,无严重并发症发生。手术时间平均160min,失血量平均510ml。依据ODI评分标准：优28例,良7例,可5例,椎间融合率100％。术后1年ODI和VAS均较术前明显减少（P〈0．01）,椎间高度、角度均明显增加（P〈0．05）。15例末次随访时仍后遗一定程度的腰痛。结论：经椎间孔入路腰椎体间融合内固定术可达到满意的椎间融合率和临床效果,特别适用于再次手术病例。     

后路椎体间微粒骨打压植骨融合

目的探讨后路椎体间微粒骨打压植骨的手术技术和临床可行性。方法对28例60岁以上腰椎退变性疾病患者、2例L1骨折脱位患者和1例T12硬脊膜瘤患者行后路椎体间微粒骨打压植骨融合。观察手术前后症状、体征、X线片腰椎前凸角、椎间隙高度指数的变化,以及手术后CT检查椎体间植骨面积。结果随访6~26个月。术前症状及体征均缓解,腰椎前凸角、椎间隙高度指数均有明显恢复,脊柱融合率达96.1%。未发生植入骨的吸收、移位和沉陷。主要有手术中硬脊膜撕裂、神经根牵拉以及手术出血等并发症。结论后路椎体间微粒骨打压植骨融合是一种可行的椎体间融合方法。     

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.