Comparison of the early results of transforaminal lumbar interbody fusion and posterior lumbar interbody fusion in symptomatic lumbar instability

Background:

Transforaminal lumbar interbody fusion (TLIF) has been preferred to posterior lumbar interbody fusion (PLIF) for different spinal disorders but there had been no study comparing their outcome in lumbar instability. A comparative retrospective analysis of the early results of TLIF and PLIF in symptomatic lumbar instability was conducted between 2005 and 2011.

Materials and Methods:

Review of the records of 102 operated cases of lumbar instability with minimum 1 year followup was done. A total of 52 cases (11 men and 41 women, mean age 46 years SD 05.88, range 40-59 years) underwent PLIF and 50 cases (14 men and 36 women, mean age 49 years SD 06.88, range 40-59 years) underwent TLIF. The surgical time, duration of hospital stay, intraoperative blood loss were compared. Self-evaluated low back pain and leg pain status (using Visual Analog Score), disability outcome (using Oswestry disability questionnaire) was analyzed. Radiological structural restoration (e.g., disc height, foraminal height, lordotic angle, and slip reduction), stability (using Posner criteria), fusion (using Hackenberg criteria), and overall functional outcome (using MacNab''s criteria) were compared.

Results:

Pain, disability, neurology, and overall functional status were significantly improved in both groups but PLIF required more operative time and caused more blood loss. Postoperative hospital stay, structural restoration, stability, and fusion had no significant difference but neural complications were relatively more with PLIF.

Conclusions:

Both methods were effective in relieving symptoms, achieving structural restoration, stability, and fusion, but TLIF had been associated with shorter operative time, less blood loss, and lesser complication rates for which it can be preferred for symptomatic lumbar instability.     

A comparative study between local bone graft with a cage and with no cage in single posterior lumbar interbody fusion (PLIF): a multicenter study

Objective

A retrospective study was performed to compare the clinical and radiological results between local bone graft with a cage and without using a cage in patients treated with posterior lumbar interbody fusion surgery.

Methods

A total of 115 consecutive patients who underwent PLIF in three institutions were evaluated from December 2005 to December 2010. 53 patients received PLIF with local bone graft combined with using one PEEK cage, and 62 patients received the PLIF with local bone graft without using a cage. The clinical data and perioperative complications of the patients in the two groups were recorded. Preoperative and postoperative radiographs were taken to calculate the disc height and the interbody bony fusion rate. Functional outcome was assessed using the Kirkaldy-Willis criteria at the follow-up time. The results between the cage group and no cage group were compared.

Results

The mean follow-up time was 19 months in no cage group and 18.5 months in cage group (P = 0.716). 20.9 % of patients (13 cases) in no cage group and 20.7 % of patients (11 cases) in cage group developed surgical complications perioperatively (P = 0.978). 51.6 % patients in no cage group got excellent functional outcome at the final follow-up while 54.7 % patients in cage group (P = 0.944). The mean interbody bony fusion time was 7.5 ± 4.5 months in no cage group and 8 ± 3.5 months in cage group (P = 0.841). According to the radiographs measurement, no significant difference was found for the disc height at each level between the two groups at the final follow-up.

Conclusion

Local bone graft without a cage is as beneficial as that with a cage for PLIF. Comparing with local bone graft using a single cage, we believe that the purely local bone graft is a more ideal way in single PLIF.     

Outcome of single level anterior cervical discectomy and fusion using nano-hydroxyapatite/polyamide-66 cage

Background:

Cages have been widely used for the anterior reconstruction and fusion of cervical spine. Nonmetal cages have become popular due to prominent stress shielding and high rate of subsidence of metallic cages. This study aims to assess fusion with n-HA/PA66 cage following one level anterior cervical discectomy.

Materials and Methods:

Forty seven consecutive patients with radiculopathy or myelopathy underwent single level ACDF using n-HA/PA66 cage. We measured the segmental lordosis and intervertebral disc height on preoperative radiographs and then calculated the loss of segmental lordosis correction and cage subsidence over followup. Fusion status was evaluated on CT scans. Odom criteria, Japanese Orthopedic Association (JOA) and Visual Analog Pain Scales (VAS) scores were used to assess the clinical results. Statistically quantitative data were analyzed while Categorical data by χ² test.

Results:

Mean correction of segmental lordosis from surgery was 6.9 ± 3.0° with a mean loss of correction of 1.7 ± 1.9°. Mean cage subsidence was 1.2 ± 0.6 mm and the rate of cage subsidence (>2 mm) was 2%. The rate of fusion success was 100%. No significant difference was found on clinical or radiographic outcomes between the patients (n=27) who were fused by n-HA/PA66 cage with pure local bone and the ones (n=20) with hybrid bone (local bone associating with bone from iliac crest).

Conclusions:

The n-HA/PA66 cage is a satisfactory reconstructing implant after anterior cervical discectomy, which can effectively promote bone graft fusion and prevent cage subsidence.     

Comparison of instrumented anterior interbody fusion with instrumented circumferential lumbar fusion

Posterior lumbar interbody fusion (PLIF) restores disc height, the load bearing ability of anterior ligaments and muscles, root canal dimensions, and spinal balance. It immobilizes the painful degenerate spinal segment and decompresses the nerve roots. Anterior lumbar interbody fusion (ALIF) does the same, but could have complications of graft extrusion, compression and instability contributing to pseudarthrosis in the absence of instrumentation. The purpose of this study was to assess and compare the outcome of instrumented circumferential fusion through a posterior approach [PLIF and posterolateral fusion (PLF)] with instrumented ALIF using the Hartshill horseshoe cage, for comparable degrees of internal disc disruption and clinical disability. It was designed as a prospective study, comparing the outcome of two methods of instrumented interbody fusion for internal disc disruption. Between April 1994 and June 1998, the senior author (N.R.B.) performed 39 instrumented ALIF procedures and 35 instrumented circumferential fusion with PLIF procedures. The second author, an independent assessor (S.M.), performed the entire review. Preoperative radiographic assessment included plain radiographs, magnetic resonance imaging (MRI) and provocative discography in all the patients. The outcome in the two groups was compared in terms of radiological improvement and clinical improvement, measured on the basis of improvement of back pain and work capacity. Preoperatively, patients were asked to fill out a questionnaire giving their demographic details, maximum walking distance and current employment status in order to establish the comparability of the two groups. Patient assessment was with the Oswestry Disability Index, quality of life questionnaire (subjective), pain drawing, visual analogue scale, disability benefit, compensation status, and psychological profile. The results of the study showed a satisfactory outcome (score30) on the subjective (quality of life questionnaire) score of 71.8% (28 patients) in the ALIF group and 74.3% (26 patients) in the PLIF group (P>0.05). On categorising Oswestry Index scores into "excellent", "better", "same", and "worse", we found no difference in outcome between the two groups: 79.5% (n=31) had satisfactory outcome with ALIF and 80% (n=28) had satisfactory outcome with PLIF. The rate of return to work was no different in the two groups. On radiological assessment, we found two nonunions in the circumferential fusion (PLIF) group (94.3% fusion rate) and indirect evidence of no nonunions in the ALIF group. There was no significant difference between the compensation rate and disability benefit rate between the two groups. There were three complications in ALIF group and four in the PLIF (circumferential) group. On the basis of these results, we conclude that it is possible to treat discogenic back pain by anterior interbody fusion with Hartshill horseshoe cage or with circumferential fusion using instrumented PLIF.     

Bone union rate with autologous iliac bone versus local bone graft in posterior lumbar interbody fusion (PLIF): a multicenter study

Purpose

The purpose of this study is to compare bone union rate between autologous iliac bone and local bone graft in patients treated by posterior lumbar interbody fusion (PLIF) using carbon cage for single level interbody fusion.

Methods

The subjects were 106 patients whose course could be observed for at least 2 years. The diagnosis was lumbar spinal canal stenosis in 46 patients, herniated lumbar disk in 12 patients and degenerative spondylolisthesis in 51 patients. Single interbody PLIF was done using iliac bone graft in 53 patients and local bone graft in 56 patients. Existence of pseudo-arthrosis on X-P (AP and lateral view) was investigated during the same follow up period.

Results

No significant differences were found in operation time and blood loss. Significant differences were also not observed in fusion grade at any follow up period or in fusion progression between the two groups. Donor site pain continued for more than 3 months in five cases (9 %). The final fusion rate was 96.3 versus 98.3 %.

Conclusions

Almost the same results in fusion were obtained from both the local bone group and the autologous iliac bone group. Fusion progression was almost the same. Complications at donor sites were seen in 19 % of the cases. From the above results, it was concluded that local bone graft is as beneficial as autologous iliac bone graft for PLIF at a single level.     

Clinical and radiographic outcomes of bilateral decompression via a unilateral approach with transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis with stenosis

Background Context

Laminectomy with posterior lumbar interbody fusion (PLIF) has been shown to achieve satisfactory clinical outcomes, but it leads to potential adverse consequences associated with extensive disruption of posterior bony and soft tissue structures.

Posterolateral versus circumferential instrumented fusion for monosegmental lumbar degenerative disc disease using an expandable cage

Background

Theoretically, 360° instrumented fusion has been considered to offer better radiological correction than PLF. Despite numerous publications, this correlation is still weak with several controversies in the relative literature.

Purpose

This prospective randomized study was designed to compare the radiological segmental results, complications and outcome of 360° instrumented fusion with the use of a single diagonal expandable PLIF device versus posterolateral pedicle screw fixation in monosegmental lumbar DDD and to show that the use of an novel expandable cage is associated with low PLIF-related complication rate compared to conventional cages reported previously.

Study design

Prospective randomized controlled clinical and radiological study.

Patient sample

Adults who suffered from monosegmental DDD were eligible for enrolment in this trial. We randomly assigned 150 patients to receive either 360° instrumented fusion (group A) with expandable cage or PLF (group B).

Outcome measures

Differences between the two groups regarding clinical parameters and radiographic sagittal measurements after 36?months of follow-up.

Methods

The record included global [T12-S1 lordosis, sagittal global spinal balance (SB) (C7-mid-femoral axis)] and segmental [segmental disc wedging (SDW), anterior (ADHr) and posterior (PDHr) disc height ratio] radiological measurements at the instrumented segment. Additionally, clinical outcome was evaluated with VAS, SF-36 (Physical function and Bodily Pain) and ODI questionnaires. Fusion was evaluated with the use of Christiansen method.

Results

In 73 and 72 participants of group A and B, respectively, who completed follow-up to 36?months, there were no differences with respect to the rate of improvement in SF-36, ODI and VAS scores. However, in the spines of group A, there was a significant increase in anterior disc height ratio (P?=?0.0057), posterior disc height (P?=?0.016) and segmental disc wedging (P?=?0.00021) without subsequent loss of correction. Fusion rate was radiologically shown in 94.5% and 87% spines of group A and B, respectively (P?>?0.2). Four and 9 spines in group A and B, respectively, showed non-union at the final observation.

Conclusions

Our findings suggest that 360° fusion offers better sagittal radiological restoration associated with circumferential fusion. However, this difference seemed not to have any medium-term clinical impact. The use of expandable cage was associated with low PLIF-related complications compared to conventional cages.     

The effect of interbody fusion cage design on the stability of the instrumented spine in response to cyclic loading: an experimental study

Background Context

In the lumbar spine, end plate preparation for the interbody fusion cages may critically affect the cage's long-term performance. This study investigated the effect of the interbody cage design on the compliance and cage subsidence of instrumented spines under cyclic compression.

Single level cervical disc herniation: A questionnaire based study on current surgical practices

Background:

Operative procedures like simple discectomy, with or without fusion and with or without instrumentation, for single level cervical disc herniation causing neck pain or neurological compromise have been described and are largely successful. However, there is a debate on definitive criteria to perform fusion (with or without instrumentation) for single level cervical disc herniation. Hence, we conducted a questionnaire based study to elicit the opinions of practicing neurosurgeons.

Materials and Methods:

About 148 neurosurgeons with atleast 12 years of operative experience on single level cervical disc herniation, utilizing the anterior approach, were enrolled in our study. All participating neurosurgeons were asked to complete a practice based questionnaire. The responses of 120 neurosurgeons were analysed.

Results:

The mean age of enrolled surgeons was 51 yrs (range 45-73) with mean surgical experience of 16.9 yrs (range 12-40 yrs) on single level cervical disc herniation. Out of 120 surgeons 10(8%) had 15-25 years experience and always preferred fusion with or without instrumentation and six (five per cent with 17-27 yrs experience had never used fusion techniques. However, 104 (87%) surgeons with 12-40 yrs experience had their own criteria based on their experiences for performing fusion with graft and instrumentation (FGI), while. 85 (75%) preferred auto graft with cage.

Conclusions:

Most of surgeons performed FGI before the age of 40, but for others, patient criteria such as job (heavier job), physical examination (especially myelopathy) and imaging findings (mild degenerative changes on X-ray and signal change in the spinal cord on MRI) were considered significant for performing FGI.     

Fusion Rates of Instrumented Lumbar Spinal Arthrodesis according to Surgical Approach: A Systematic Review of Randomized Trials

Background

Lumbar spine fusion rates can vary according to the surgical technique. Although many studies on spinal fusion have been conducted and reported, the heterogeneity of the study designs and data handling make it difficult to identify which approach yields the highest fusion rate. This paper reviews studies that compared the lumbosacral fusion rates achieved with different surgical techniques.

Methods

Relevant randomized trials comparing the fusion rates of different surgical approaches for instrumented lumbosacral spinal fusion surgery were identified through highly sensitive and targeted keyword search strategies. A methodological quality assessment was performed according to the checklist suggested by the Cochrane Collaboration Back Review Group. Qualitative analysis was performed.

Results

A literature search identified six randomized controlled trials (RCTs) comparing the fusion rates of different surgical approaches. One trial compared anterior lumbar interbody fusion (ALIF) plus adjunctive posterior transpedicular instrumentation with circumferential fusion and posterolateral fusion (PLF) with posterior lumbar interbody fusion (PLIF). Three studies compared PLF with circumferential fusion. One study compared three fusion approaches: PLF, PLIF and circumferential fusion.

Conclusions

One low quality RCT reported no difference in fusion rate between ALIF with posterior transpedicular instrumentation and circumferential fusion, and PLIF and circumferential fusion. There is moderate evidence suggesting no difference in fusion rate between PLF and PLIF. The evidence on the fusion rate of circumferential fusion compared to PLF from qualitative analysis was conflicting. However, no general conclusion could be made due to the scarcity of data, heterogeneity of the trials included, and some methodological defects of the six studies reviewed.     

Are 2 cages needed with instrumented PLIF? A comparison of 1 versus 2 interbody cages in a military population

Bovine biomechanical data have demonstrated adequate stability of a single threaded interbody cage when combined with a unilateral facet screw during posterior lumbar disc excision and interbody fusion (PLIF). Instrumented PLIF surgery using 1 versus 2 interbody cages was studied in 35 military men with disc disease and chronic low back pain. All patients underwent instrumented PLIF with bilateral diskectomy and partial facetectomy, pedicle screws, autogenous iliac crest bone graft, 1 or 2 interbody cages, and posterior lateral fusion. After an average of 15 months' follow-up, the 2-cage group had a higher rate of dural tear, but rates of other complications, hospital stay, fusion rates, pain levels, functional outcomes, and patient satisfaction were good and did not differ between groups. Costs were higher for the 2-cage group by 1728 dollars per patient.     

Spinaplasty following lumbar laminectomy for multilevel lumbar spinal stenosis to prevent iatrogenic instability

Background:

Iatrogenic instability following laminectomy occurs in patients with degenerative lumbar canal stenosis. Long segment fusions to obviate postoperative instability result in loss of motion of lumbar spine and predisposes to adjacent level degeneration. The best alternative would be an adequate decompressive laminectomy with a nonfusion technique of preserving the posterior ligament complex integrity. We report a retrospective analysis of multilevel lumbar canal stenosis that were operated for posterior decompression and underwent spinaplasty to preserve posterior ligament complex integrity for outcome of decompression and iatrogenic instability.

Materials and Methods:

610 patients of degenerative lumbar canal stenosis (n=520) and development spinal canal stenosis (n=90), with a mean age 58 years (33–85 years), underwent multilevel laminectomies and spinaplasty procedure. At followup, changes in the posture while walking, increase in the walking distance, improvement in the dysesthesia in lower limb, the motor power, capability to negotiate stairs and sphincter function were assessed. Forward excursion of vertebrae more than 4 mm in flexion–extension lateral X-ray of the spine as compared to the preoperative movements was considered as the iatrogenic instability. Clinical assessment was done in standing posture regarding active flexion–extension movement, lateral bending and rotations

Results:

All patients were followed up from 3 to 10 years. None of the patients had neurological deterioration or pain or catch while movement. Walking distance improved by 5–10 times, with marked relief (70–90%) in neurogenic claudication and preoperative stooping posture, with improvement in sensation and motor power. There was no significant difference in the sagittal alignment as well as anterior translation. Two patients with concomitant scoliosis and one with cauda equine syndrome had incomplete recovery. Two patients who developed disc protrusion, underwent a second operation for a symptomatic disc prolapse.

Conclusion:

Spinaplasty following posterior decompression for multilevel lumbar canal stenosis is a simple operation, without any serious complications, retaining median structures, maintaining the tension band and the strength with least disturbance of kinematics, mobility, stability and lordosis of the lumbar spine.     

两种后路椎间植骨方法治疗腰椎滑脱的疗效比较研究

目的探讨后路椎间融合(pasterior lumber interbody fusion,PLIF)应用Cage及椎弓根钉技术后,有无必要加用椎间自体植骨治疗腰椎滑脱. 方法 2003年3月～2004年3月,对27例腰椎滑脱症患者行后路椎间植骨融合术.采用Cage及椎弓根钉技术治疗15例(A组),其中男4例,女11例;年龄53～68岁.病变部位位于L4节段9例,L5节段6例;术前平均椎间隙高度为5.4±2.3 mm,平均滑脱率为36.8%±7.2%.采用Cage及椎弓根钉技术加用椎间自体植骨治疗12例(B组),其中男3例,女9例;年龄53～65岁.病变部位位于L4节段8例, L5节段4例;术前平均椎间隙高度为5.7±2.5 mm,平均滑脱率为37.8%±6.2%.对两组患者进行失血量、住院日、疼痛度和缓解程度、融合率及并发症,以及术后椎间隙高度、滑脱率及融合率进行分析比较. 结果术后患者均获随访24～38个月,A组随访时间24～36个月,B组随访时间24～38个月.两组患者随访时间,性别,病变部位,术前椎间隙高度,平均滑脱率,失血量,住院日,融合时间均无统计学差异(P>0.05);但疼痛度及缓解程度、融合率,B组均好于A组,差异有统计学意义(P<0.05).A组最后随访平均椎间隙高度5.8±2.2 mm,平均滑脱率为25.6%±7.2%,B组为6.2±2.5 mm和24.1%±7.4%,两组比较差异有统计学意义(P<0.05). 结论 PLIE手术应用Cage及椎弓根钉技术加用椎间自体植骨,有助于恢复和保持腰骶椎生理曲度,防止后期的椎间隙高度丢失及滑脱率的增加,可能利于手术后长期疗效的保持.     

The efficacy of porous hydroxyapatite bone chip as an extender of local bone graft in posterior lumbar interbody fusion

Objective

To evaluate whether a synthetic bone chip made of porous hydroxyapatite can effectively extend local decompressed bone graft in instrumented posterior lumbar interbody fusion (PLIF).

Methods

130 patients, 165 segments, who had undergone PLIF with cages and instrumentation for single or double level due to degenerative conditions, were investigated retrospectively by independent blinded observer. According to the material of graft, patients were divided into three groups. HA group (19 patients, 25 segments): with hydroxyapatite bone chip in addition to autologous local decompressed bone, IBG group (25 patients, 28 segments): with autologous iliac crest bone graft in addition to local decompressed bone and LB group (86 patients, 112 segments): with local decompressed bone only. Radiologic and clinical outcome were compared among groups and postoperative complications, transfusion, time and cost of operation and duration of hospitalization were also investigated.

Results

Radiologic fusion rate and clinical outcome were not different. Economic cost, transfusion and hospital stay were also similar. But operation time was significantly longer in IBG group than in other groups. There were no lasting complications associated with HA and LB group with contrast to five cases with persisting donor site pain in IBG group.

Conclusion

Porous hydroxyapatite bone chip is a useful bone graft extender in PLIF when used in conjunction with local decompressed bone.     

Extension CT scan: its suitability for assessing fusion after posterior lumbar interbody fusion

Posterior lumbar interbody fusion (PLIF) is a popular procedure for treating lumbar canal stenosis with spinal instability, and several reports concerning fusion assessment methods exist. However, there are currently no definitive criteria for diagnosing a successful interbody fusion in the lumbar spine. We suggested evaluating fusion status using computed tomography (CT) in extension position to detect pseudoarthrosis more precisely. The purpose of this study was to evaluate its usefulness for determining bone union quality after PLIF. Eighty-one patients who underwent PLIF at 97 levels were retrospectively enrolled. The study population included 48 men and 33 women (mean age 58.9 years, range 21–85 years). Patients were followed up for more than 12 months after surgery. The mean follow-up period was 27.6 months (range 14–49 months). Fusion status was evaluated using three ways: flexion–extension radiographs, CT images in flexion and extension position. In the flexion–extension radiographs, mobility of more than 3°, a remaining clear zone, or an uncertain bone connection constituted an incomplete union. For CT images, a remaining clear zone, a gas pattern, or an uncertain bone connection constituted an incomplete union. Flexion–extension radiographs demonstrated a solid fusion in 90.7% of the 97 levels at 10.7 months postoperatively. When fusion was demonstrated on flexion–extension radiographs, the rate of fusion affirmed by flexion CT and extension CT was 87.6 and 69.1% of the levels assessed, respectively. The rate of pseudoarthrosis detected on extension CT images was significantly higher than that on flexion–extension radiographs (P < 0.001) and flexion CT (P < 0.01). The rate of fusion achieved on extension CT was 85.6% at 15.1 months postoperatively. Extension CT could detect pseudoarthrosis more clearly than flexion–extension radiography and flexion CT. The CT images are influenced by body position and dilating anterior disc space in extension CT contributes to detect pseudoarthrodesis. Thus, extension CT was a useful method for assessing fusion status after PLIF.     

Posterior lumbar interbody fusion (PLIF) with cages and local bone graft in the treatment of spinal stenosis

Posterior lumbar interbody fusion (PLIF) implants are increasingly being used for 360 degrees fusion after decompression of lumbar spinal stenosis combined with degenerative instability. Both titanium and PEEK (PolyEtherEtherKetone) implants are commonly used. Assessing the clinical and radiological results as well as typical complications, such as migration of the cages, is important. In addition, questions such as which radiological parameters can be used to assess successful fusion, and whether the exclusive use of local bone graft is sufficient, are frequently debated. We prospectively evaluated 30 patients after PLIF instrumentation for degenerative lumbar spinal canal stenosis, over a course of 42 months. In all cases, titanium cages and local bone graft were used for spondylodesis. The follow-up protocol of these 30 cases included standardised clinical and radiological evaluation at 3, 6, 12 and 42 months after surgery. Overall satisfactory results were achieved. With one exception, a stable result was achieved with restoration of the intervertebral space in the anterior column. After 42 months of follow-up in most cases, a radiologically visible loss of disc space height can be demonstrated. Clinically relevant migration of the cage in the dorsal direction was detected in one case. Based on our experience, posterior lumbar interbody fusion (PLIF) can be recommended for the treatment of monosegmental and bisegmental spinal stenosis, with or without segmental instability. Postoperative evaluation is mainly based on clinical parameters since the titanium implant affects the diagnostic value of imaging studies and is responsible for artefacts. The results observed in our group of patients suggest that local autologous bone graft procured from the posterior elements after decompression is an adequate material for bone grafting in this procedure.     

Posterolateral fusion using laminectomy bone chips in the treatment of lumbar spondylolisthesis

We retrospectively reviewed the outcome of posterolateral fusion (PLF) in 136 patients with lumbar spondylolisthesis (LS), who had undergone posterior decompression laminectomy with foraminotomy and PLF using laminectomy bone chips as bone graft, with reduction of the slipped vertebra with transpedicle screws, between 1993 and 2003. Diagnosis of LS was confirmed by plain lumbar radiography, with computed tomography (CT) scan or magnetic resonance imaging (MRI) studies performed to confirm an associated condition, such as ruptured disc and spinal stenosis. The outcome of spinal fusion was good with 129 (94.85%) patients attaining solid fusion, while failed fusion was noted in seven (5.15%) patients. None of our patients complained of excessive postoperative wound pain. Additionally, no complications, such as wound infection, were encountered. Proper decortication of the posterior paravertebral gutters with an osteotome and removal of all soft tissues from the laminectomy bone chips are significant factors contributing to the successful outcome of the laminectomy bone chips in PLF. The fusion rate obtained with this type of autogenous bone graft is comparable to that of the iliac bone crest autogenous graft; hence, it is a good substitute for the iliac crest bone autogenous graft in performing PLF in treating lumbar spondylolisthesis.     

The use of beta-tricalcium phosphate and bone marrow aspirate as a bone graft substitute in posterior lumbar interbody fusion

Purpose

Due to the disadvantages of iliac crest bone and the poor bone quality of autograft gained from decompression surgery, alternative filling materials for posterior lumbar interbody fusion cages have been developed. β-Tricalcium phosphate is widely used in cages. However, data regarding the fusion rate of β-TCP assessed by computer tomography are currently not available.

Materials

A prospective clinical trial involving 34 patients (56.7 years) was performed: 26 patients were treated with single-level, five patients double-level and three patients triple-level PLIF filled with β-TCP and bone marrow aspirate perfusion, and additional posterior pedicle screw fixation. Fusion was assessed by CT and X-rays 1 year after surgery using a validated fusion scale published previously. Functional status was evaluated with the visual analogue scale and the Oswestry Disability Index before and 1 year after surgery.

Results

Forty-five levels in 34 patients were evaluated by CT and X-ray with a follow-up period of at least 1 year. Clinically, the average ODI and VAS for leg and back scores improved significantly (P < 0.001). CT assessment revealed solid fusion in 12 levels (26.67 %) and indeterminate fusion in 15 levels (34.09 %). Inadequate fusion (non-union) was detected in 17 levels (38.63 %).

Conclusion

The technique of PLIF using β-TCP yielded a good clinical outcome 1 year after surgery, however, a high rate of pseudoarthrosis was found in this series therefore, we do not recommend β-TCP as a bone graft substitute using the PLIF technique.     

Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis

Background:

Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD) after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters.

Materials and Methods:

98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI), medical comorbidities and bone mineral density (BMD). The radiological parameters taken into consideration were Cobb''s angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI) and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level) and posterolateral lumbar interbody fusion (PLIF). Clinical outcomes were assessed with the Visual Analogue Score (VAS) and Oswestry Disability Index (ODI).

Results:

ASD was present in 44 (44.9%) patients at an average period of 48.0 months (range 6-98 months). Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI) and age at operation (P = 0.0001, 0.0364). There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531).

Conclusions:

Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI) were at a higher risk of developing ASD.     

Prophylactic perioperative dexamethasone decreases the incidence of postoperative C5 palsies after a posterior cervical laminectomy and fusion

Background Context

Postoperative C5 palsy is a well-known complication of cervical decompression procedures. Studies have shown that posterior laminectomy and fusions confer the greatest risk of C5 palsy. Despite this, pharmacologic preventive measures remain unknown. We hypothesize that prophylactic perioperative dexamethasone (DEX) will decrease the rate of postoperative C5 palsy in patients undergoing a multilevel posterior cervical laminectomy and fusion.