Current Tendencies of Posterior Lumbar Interbody Fusion with a Pedicle Screw in the Osteoporotic Spine-Advances and Concerns

Review Article

Austin J Musculoskelet Disord. 2014;1(2): 1011.

Current Tendencies of Posterior Lumbar Interbody Fusion with a Pedicle Screw in the Osteoporotic Spine-Advances and Concerns

Okuyama K1*, Miyakoshi N2, Suzuki T3 and ShimadaY2

1Department of Orthopedic Surgery, Akita Rosai Hospital, Japan

2Department of Orthopedic Surgery, Akita University School of Medicine, Japan

3Department of Orthopedic Surgery, Akita Red Cross Hospital, Japan

*Corresponding author: Okuyama K, Department of Orthopedic Surgery, Akita Rosai Hospital, Karuizawa Aza Shimotai 30, Ohdate, ZIP 018-56, Japan

Received: October 29, 2014; Accepted: December 01, 2014; Published: December 02, 2014


PLIF with PS has brought a great evolution in spinal instrumentation surgery because it enables us to perform 3-D correction and solid stabilization of the affected segment immediately after surgery. But complications of PLIF with PS, such as screw loosening, non-union and PJF have not been completely solved, especially in elderly patients with osteoporosis. Herein, we review articles focusing on PLIF with PS and its complication in the osteoporotic spine. Moreover, the current tendencies are discussed with our personal experiences in clinical cases.

Keywords: Posterior Lumbar Interbody Fusion; Pedicle Screw; Osteoporosis; Complications; Current Tendencies; Aging Society


PLIF: Posterior Lumbar Interbody Fusion; PS: Pedicle Screw; 3-D: Three Dimensional; IBD: Interbody Device; BMD: Bone Mineral Density; QCT: Quantitative Computed Tomography; DEXA: Dual Energy X-ray Absorptiometry; PJF(K): Proximal Junctional Fracture(Kyphosis); PEEK: Polyetheretherketone; CFR/PEEK: Carbon Fiber-Reinforced Polyetheretherketone; Ti2448: Ti-24Nb-4Zr-7.9Sn; CPC: Calcium Phosphate Cement; PMMA: Polymethylmethacrylate; EPS: Expandable Pedicle Screw; CBT: Cortical Bone Trajectory; PTH: Parathyroid Hormone; PLF: Posterior Lumbar Fusion; LLIF: Lumbar Lateral Interbody fusion; XLIF®: Extreme Lumbar Lateral Interbody Fusion; DLIF: Direct Lateral Interbody Fusion


History and current Status of PLIF and PS

PLIF with PS is very useful and has become a standard procedure of lumbar fusion surgery nowadays. It has provided a great advantage in performing 3-D correction and solid stabilization of affected segments immediately after surgery. To my best knowledge, PLIF was theoretically proposed as one of the procedures for lumbar degenerative diseases by Capener in 1932 [1]. In 1944, Briggs et al, performed the primitive PLIF procedure as an intercorpus fusion with bone chips although the fusion failed [2]. In the 1940’s~50’s, conventional PLIF without instrumentation was pioneered by Cloward to treat painful intervertebral discs, but biomechanical stability of PLIF using the autologous bone without instrumentation was too fragile to allow an early rehabilitation program at that time [3]. As a result of this downside, PLIF without instrumentation had not been accepted as a standard surgical technique until the late 1980’s. Meanwhile, Judet and Roy-Camille proposed the original idea of PS in 1970 [4]. At first, it was described in French as a pedicle screw plate for traumatic disorders in the thoracolumbar and lumbar spine, and was later written in English in 1986 [5].

There is a cornerstone article that revived the PLIF procedure. Steffee and Sitkowski stated that PLIF, in conjunction with PS, was biomechanically ideal, and reported no dislocation, absorption and pseudoarthrosis of interbody grafts in 67 patients with degenerative disorders in 1988 [6]. After this statement, numerous studies demonstrated that PLIF with PS enhanced the osteosynthesis success rate of the spinal arthrodesis in lumbar degenerative diseases. But the problem of grafted bone collapse and/or non-union, especially in the osteoporotic spine, has not been completely resolved. Allograft bone was also proposed as a PLIF material in the same decade, but it did not gain instant stability of the fixed segment. Furthermore, it introduced a risk of blood-borne pathogen transmission and decreased bone healing. Because of the disadvantages and risks, PLIF using allograft bone, has not been accepted among orthopedic surgeons.

In the 1990’s and early 2000’s, variable kinds of IBDs, which provide solid anterior column support of the functional spinal unit, were introduced and used in vivo for lumbar arthrodesis. IBD has extremely improved the biomechanical stability of PLIF with PS. Lots of articles that describe excellent outcomes of PLIF with PS& IBD have also been published [7-9]. After the development of IBD, the tri-cortical or bi-cortical strut bone graft, which had been used in the original PLIF procedure, was considered non-essential. For instance, Kanayama et al. biomechanically proved that interbody fusion constructs with threaded or non-threaded interbody cages had more solid stiffness in comparison to a calf spine in intact condition [10].

In terms of bone harvesting, the morbidity of harvesting a tri-cortical autologous graft bone from the ilium is also very significant, including a persistent donor site pain [11,12]. If PLIF could be carried out without harvesting autograft bone from the iliac crest, it could be a great benefit for both patients and orthopedic surgeons. Several authors reported clinical efficacy of PLIF using local bone with IBD instead of autologous iliac bone graft. Hashimoto et al. performed a clinical study of 25 single-level PLIF cases using carbon cages with a mixture of the local morselized bone and bioactive ceramic granules, and their result demonstrated a 100% bone union rate including 2 cases of collapsed union [13]. In 2003, Miura et al. reported a 100% bone union rate in 32 patients who underwent PLIF using carbon cages filled with only the local bone and PS [14]. In 2007, we also reported an excellent bone union in PLIF for degenerative spondylolisthesis using 2 titanium cages filled with the excised local bone. Our fusion rate was 93.5% at an averaged 2.3 (2.0 - 4.5) years after follow-up [15].

Several disadvantages of PLIF with PS & IBD are the risks of perioperative complications, including surgical invasion and an overall high technical demand. Especially, it has a high risk of neurological complication because the affected lumbar canal is not wide enough to permit safe passage of materials into the interbody space [16,17]. In our institute, to avoid neurological complications, the inferior one-half of the lamina, and the inferior articular process are en-block excised in the cephalad vertebra. The superior articular process is partially excised at the margin of the pedicle in the caudad vertebra in the non-isthmic cases. The spinous processus, supraspinous and interspinous ligaments to the adjacent vertebra are preserved. This surgical step permits safe passage of IBDs and the local resected bone into the interbody space while the caudad and cephlad nerve roots are directly retracted. Two spacers or cages could be easily placed at the lateral portion of the interbody space [15]. In our initial series of this PLIF procedure, transient nerve root palsy and dural damage without neural deficit were recorded in 12 and 6 of 148 patients, respectively [18]. PLIF with PS & IBD can correct and stabilize the three columns of the affected spinal segment, while also allowing direct observation of the neural tissues in the posterior approach, especially when the facet joints are entirely resected. Nowadays, there is no doubt that PLIF with PS& IBD is accepted as a golden standard procedure for treatment of both degenerative and traumatic disorders. In the latest decade, minimally invasive PLIF, and transforaminal interbody fusion with PS & IBD have also been introduced and are gaining popularity as new alternatives to the conventional PLIF with PS & IBD.

Problems of PLIF with PS in the osteoporotic spine

One of the common problems of PS is screw loosening (radiolucency in the bone-screw interface on X-ray) which may lead to a backout of PS, loss of correction and final non-union of PLIF (Figures 1 and 2). PS loosening was mainly caused by cyclic caudo-cephalad toggling at the bone-screw interface when an axial compression load was transmitted through the plate or rod to the screw [19]. Loosening of PS can easily occur if PS is anchored into the osteoporotic vertebral body through the pedicle. In a selected survey of the American Back Society, the rate of screw loosening was observed in 0.81% of 617 cases, and was ranging from 0.6 to 11 % in the literatures reviewed by Esses et al. [20]. It has been analyzed that several factors affecting the stability of PS, such as its length, outer diameter, design, fitness in the pedicle, BMD of the vertebra and elasticity of cancellous bone in 1980’s ~90’s [21,22]. In particular, BMD is supposed to be a very important parameter influencing the stability of PS [23-27]. A very high correlation between BMD and the stability of PS was studied and confirmed. Some thresholds for the implant failure in PS have also been proposed from the view point of BMD. Wittenberg has concluded that early loosening of PS may be expected at BMD less than 90mg/cc measured by QCT [24]. We also confirmed that the vertebrae with an average BMD of 95±33.3 (mean±SD) mg/ml by QCT could not be anatomically stabilized by PS alone in cadaveric specimens [27]. In general, PLIF with PS& IBD is indicative for patients with degenerative spondylolisthesis, kyphoscoliosis, and vertebral fracture and so forth to correct and stabilize the unstable deformities. But most of the patients are ironically associated with osteoporosis more or less. In 2001, we have proposed that BMD value of 0.674 ± 0.104 g/cm2 and 0.720 ± 0.078g/ cm2 by DEXA in the lumbar spine is a specific threshold below which non-union and screw loosening develops, respectively when PLIF with PS & IBD is carried out in patients with lumbar degenerative disorders [28]. Improving clinical results in the current situation is a major hurdle, and unfortunately, loosing of PS is still unsolved, and is the top priority that orthopedic surgeons face.