The predictive value of preoperative paraspinal muscle morphometry on complications after lumbar surgery: a systematic review

Purpose The effect of paraspinal muscles atrophy and fat infiltration (FI) on the complications of spinal surgery has not been established. Methods A review of the literature was conducted from a search of the PubMed, EMBASE, and Web of Science databases from inception through January 2021. The literature was searched and assessed by independent reviewers based on criteria that included an assessment of preoperative paraspinal muscle morphology in addition to measuring its relationship to surgical complications. All relevant papers were assessed for risk of bias according to the modified Newcastle Ottawa Scale and the Joanna Briggs Institute Critical Appraisal Tools. A narrative synthesis was conducted. Results The initial search yielded 5632 studies, of which 16 studies were included in the analysis. All included studies were at a low risk of bias. There existed strong evidence that the atrophy and FI of paraspinal muscles had an association with the development of bone nonunion (two high quality studies), pedicle screw loosening (two high quality studies), adjacent segment degeneration (three high quality studies) and proximal junctional kyphosis (five high quality studies) after lumbar surgery. Besides, there is also limited evidence for association between atrophy and FI of paraspinal extensor muscles and less local and global curve improvement. Conclusions Strong evidence was found for an association between preoperative paraspinal muscle degeneration and multiple postoperative complications after lumbar surgery. However, the findings should be interpreted with caution due to the small quantity of the available literature and high heterogeneity among studies.

A New Test Method for in vitro Evaluation of Pedicle Screw Loosening Potential

This paper proposes a new testing method based on the toggle effect under transverse loads (cranial-caudal) to investigate the loosening potential of pedicular screw designs. A three-step in vitro testing procedure was developed to mimic the loosening mechanism of pedicular screws. Firstly, the pedicular screw of a certain design is inserted into a bone substitute model specifically designed for the test. Secondly, a controlled cyclic cranial-caudal loading is applied transversally to the longitudinal axis of the screw for three ascendent load levels (staircase) by a pre-determined number of load cycles. Lastly, each pedicular screw is adjusted and submitted to axial pull-out quasi-static testing. The results are used to calculate a loosening index that, together with statistical analysis, indicates the potential for loosening of the specific design evaluated. The proposed testing method effectively provides a simulated environment to evaluate the loosening potential of pedicular screw designs. The proposed loosening index calculation may be used to compare different pedicular screw designs. The proposed methodology was verified as a valuable tool to investigate the influence of the cranial-caudal loads on pedicular screw behavior. It offers a new alternative for use in pre-clinical studies on the loosening potential of pedicular screw designs.

Percutaneous pedicle screw fixation combined with percutaneous vertebroplasty for the treatment of thoracic and lumbar metastatic tumor

Background Evaluation of the clinical efficacy of percutaneous pedicle screw fixation (PPSF) combined with percutaneous vertebroplasty (PVP) in the treatment of thoracic and lumbar metastatic tumor.Methods 20 patients with thoracic and lumbar metastatic tumor were treated with PPSF combined with PVP and followed up 6–25 months. Using the visual analog scale (VAS) and the Barthel Index of Activities of Daily Living (BIADL) to evaluate pain intensity and quality of life before surgery and at 7 days, 3 months, 6 months after treatment.Results In this study, a total of 20 patients were followed up for 6–25 months (mean time was 14.10 months). The VAS scores of all patients were significantly decreased, while the BIADL scores were significantly increased. No patients suffered from complications such as infection, pedicle screw loosening or PMMA oozing. Spine stability was observed in all the surviving patients during the follow-up.Conclusions PPSF combined with PVP is a potentially viable treatment for thoracolumbar metastases in patients with poor systemic condition or patients who refuse to undergo a conventional open procedure such as en bloc corpectomy, and in the presence of vertebral instability or pathological fracture without significant spinal compression.

The comparison between anterior and posterior approaches for removal of infected lumbar interbody cages and a proposal regarding the use of endoscope-assisted technique

Background In cases of postoperative deep wound infection after interbody fusion with cages, it is often difficult to decide whether to preserve or remove the cages, and there is no consensus on the optimal approach for removing cages. The aim of this study was to investigate the surgical management of cage infection after lumbar interbody fusion. Methods A retrospective study was conducted between January 2012 and August 2018. Patients were included if they had postoperative deep wound infection and required cage removal. Clinical outcomes, including operative parameters, visual analog scale, neurologic status, and fusion status, were assessed and compared between anterior and posterior approaches for cage removal. Results Of 130 patients who developed postoperative infection and required surgical debridement, 25 (27 levels) were diagnosed with cage infection. Twelve underwent an anterior approach, while 13 underwent cage removal with a posterior approach. Significant differences were observed between the anterior and posterior approaches in elapsed time to the diagnosis of cage infection, operative time, and hospital stay. All patients had better or stationary American Spinal Injury Association impairment scale, but one case of recurrence in adjacent disc 3 months after the surgery. Conclusions Both anterior and posterior approaches for cage removal, followed by interbody debridement and fusion with bone grafts, were feasible methods and offered promising results. An anterior approach often requires an additional extension of posterior instrumentation due to the high incidence of concurrent pedicle screw loosening. The use of an endoscope-assisted technique is suggested to facilitate safe removal of cages.

Incidence, Risk, and Outcome of Pedicle Screw Loosening in Degenerative Lumbar Scoliosis Patients Undergoing Long-Segment Fusion

Study Design: Retrospective study. Objective: To investigate the incidence, risk factors, and outcomes of pedicle screw loosening in degenerative lumbar scoliosis (DLS) undergoing long-segment spinal fusion surgery. Methods: One hundred and thirty DLS patients who underwent long-segment fusion surgery with at least a 12-month follow-up were studied. The incidence and risk factors of screw loosening were investigated. VAS, SRS-22, and ODI scores were obtained preoperatively and at follow-up. Results: One hundred and sixty-eight of 1784 (9.4%) screws showed evidence of loosening in 71 (54.6%) patients. Three patients required revision surgery. Screw loosening rates according to vertebral insertion level were lowest instrumented vertebra (LIV): 45.4%; uppermost instrumented vertebra (UIV):17.7%; one vertebra above the LIV: 0.5%; 2 vertebrae above the LIV: 0.4%. Multiple logistic regression analysis of possible risk factors indicated that preoperative lateral subluxation ≥8 mm (odds ratio [OR]: 2.68, 95% confidence interval [CI]: 1.16-6.20), osteopenia (OR: 5.52, 95% CI: 1.64-18.56), osteoporosis (OR: 8.19, 95% CI: 2.40-27.97), fusion to sacrum (OR: 2.55, 95% CI: 1.12-5.83), postoperative TLK greater than 10° (OR: 2.63, 95% CI: 1.14-6.04) and SVA imbalance (OR: 3.44, 95% CI: 1.17-10.14) were statistically significant. No difference was noted in preoperative, follow-up, and change of VAS, ODI, and SRS-22 scores. Conclusions: Screw loosening in DLS underwent long-segment surgery is common and tends to occur in the LIV or UIV. Lateral subluxation ≥8 mm, osteopenia, osteoporosis, fusion to the sacrum, postoperative TLK greater than 10°, and SVA imbalance were the independent influencing factors. Screw loosening can be asymptomatic, while longer-term follow-up is required.

Minimally Invasive Transforaminal Lumbar Interbody Fusion for 2-Level Degenerative Lumbar Disease in Patients With Osteoporosis: Long-Term Clinical and Radiographic Outcomes

BACKGROUND Spine fusion surgery in osteoporosis remains controversial because it is related to a high incidence of osteoporosis-related complications, such as cage nonfusion, pedicle screw loosening, and new vertebral compression fractures (VCFs). OBJECTIVE To treat 2-level degenerative lumbar disease in osteoporosis patients as an effective and safe surgical treatment for long-term results using minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). METHODS We retrospectively assessed 12 patients with osteoporosis who underwent MIS-TLIF on L4 and L5 between 2011 and 2012 to assess the clinical and radiographic results for 2-level lumbar degenerative spine disease. All patients were followed-up for at least 2 yr after surgery and assessed by using X-ray. Basic patient data and clinical and radiological outcomes were collected and analyzed. RESULTS Of all 12 patients, 11/12 (91.6%) and 1/12 (8.3%) demonstrated cage fusion and cage subsidence, respectively. Pedicle screw loosening was found in 1/12 (8.3%) patients. The P-values calculated using the F-test for changes in the vertebral body height pre- and postoperation in L3, L4, and L5 were .69, .87, and .39, respectively. The data revealed no significant variants of new VCFs. CONCLUSION MIS-TLIF provided a high cage fusion rate and low pedicle screw loosening rate in patients with osteoporosis with 2-level degenerative spine disease. Furthermore, no new VCFs were found in long-term follow-up. The clinical outcomes also demonstrated no significant difference compared with traditional open spine fusion surgery. Therefore, MIS-TLIF could be considered an effective and safe surgical treatment modality for 2-level degenerative spine disease in osteoporosis.

Carbon-fiber reinforced PEEK instrumentation for spondylodiscitis: a single center experience on safety and efficacy

Radiolucent carbon-fiber-reinforced (CFR) polyethyl-ether-ether-ketone (PEEK) has been established in spinal instrumentation for oncological reasons. Laboratory data reported comparable bacterial adhesion as titanium. Thus, using of CFR-PEEK spinal instrumentation for spondylodiscitis bases on artifact-free imaging to evaluate therapeutic success. Studies comparing the rate of pedicle screw loosening and relapse of spondylodiscitis following titanium versus CFR-PEEK instrumentation do not exist so far. This study evaluates the rate of pedicle screw loosening and recurrence of spondylodiscitis after CFR-PEEK instrumentation for spondylodiscitis compared to titanium. We conducted a prospective single center study between June 2018 and March 2019 on consecutive 23 patients with thoracolumbar spondylodiscitis. Imaging data was evaluated for screw loosening at a minimum of three months after surgery. A matched-pair analysis was performed using spondylodiscitis cases between 2014 and 2016 using titanium instrumentation for equal localization, surgery, and microorganism class. Among 17 cases with follow-up imaging, six cases (35%) showed screw loosening while only 14% (two patients) with titanium instrumentation were loosened (p = 0.004). In both groups the most frequent bacterium was Staphylococcus aureus, followed by Staphylococcus epidermidis. From the S. aureus cases, one infection in both groups was caused by methicillin resistant species (MRSA). No difference was found in the rate of 360° fusion in either group due to matching criteria. As opposed to other indications CFR-PEEK screws show more loosening than titanium in this series with two potentially underlying reasons: a probably stronger bacterial adhesion on CFR-PEEK in vivo as shown by a statistical trend in vitro and instrumentation of spondylytic vertebrae. Until these factors are validated, we advise caution when implanting CFR-PEEK screws in infectious cases.

Incidence and Predictive Factors of Distal Pedicle Screw Loosening Followed Posterior Corrective Surgery for Degenerative Lumbar Scoliosis

BackgroundThe aim of this study was to identify the prevalence of distal pedicle screw loosening (DPSL) following posterior decompression and instrumented fusion for DLS, to search for predictable risk factors for DPSL, and hope to provide references in decision making and surgical planning for spine surgeons. MethodsOne hundred and fifty-three consecutive DLS patients surgically treated between January 2013 and July 2018 were retrospectively reviewed. The diagnostic criteria for DPSL developed by X-ray include the radiolucent area (thicker than 1 mm) around screw and the “double halo” sign defined as the presence of radiolucent area and radiopaque rim at the same X-ray. According to the occurrence of DPSL at two-year follow-up, patients were divided into two groups: study group (screw loosening) and control group (without screw loosening). To investigate predictive factors for distal pedicle screw loosening, three categorized factors were analyzed statistically.ResultsDPSL was detected in 72 of 153 patients (47.1%) at two-year follow up, and were enrolled as study group. Another 81 patients presented no screw loosening at two-year follow up, and were enrolled as control group. Hounsfield unit (HU) value was lower in study group than that in control group. Fusion level was longer in study group than that in control group. Lower instrumented vertebrae on L5 was less in study group than that in control group. Posterolateral fusion was less in study group than that in control group. Preoperative Cobb angle, postoperative Cobb angle, Cobb angle correction, preoperative lumbosacral coronal angle (LSCA), LSCA correction, preoperative thoracolumbar junction (TL), postoperative TL were larger in study group than those in control group. Logistic regression analysis revealed that low Bone mineral density (BMD) (<169 HU), posterolateral fusion, Cobb angle correction (>16 degrees), LSCA correction (>9 degrees) were independently associated with DPSL.ConclusionsThe incidence of DPSL following posterior decompression and instrumented fusion for DLS is 47.1%. Low BMD, large correction of both main curve and fractional curve are predictive factors for DPSL, while posterolateral fusion is a protective factor.