Correlation of bone density to screw loosening in dynamic stabilization: an analysis of 176 patients

AbstractAlthough osteoporosis has negative impacts on lumbar fusion, its effects on screw loosening in dynamic stabilization remain elusive. We aimed to correlate bone mineral density (BMD) with screw loosening in Dynesys dynamic stabilization (DDS). Consecutive patients who underwent 2- or 3-level DDS for spondylosis, recurrent disc herniations, or low-grade spondylolisthesis at L3-5 were retrospectively reviewed. BMD was assessed by the Hounsfield Unit (HU) in vertebral bodies (VB) and pedicles with and without cortical bone (CB) on pre-operative computed tomography (CT). Screw loosening was assessed by radiographs and confirmed by CT. HU values were compared between the loosened and intact screws. 176 patients and 918 screws were analyzed with 78 loosened screws found in 36 patients (mean follow-up: 43.4 months). The HU values of VB were similar in loosened and intact screws (p = 0.14). The HU values of pedicles were insignificantly less in loosened than intact screws (including CB: 286.70 ± 118.97 vs. 297.31 ± 110.99, p = 0.45; excluding CB: 238.48 ± 114.90 vs. 240.51 ± 108.91, p = 0.88). All patients had clinical improvements. In conclusion, the HU values, as a surrogate for BMD, were unrelated to screw loosening in DDS. Therefore, patients with compromised BMD might be potential candidates for dynamic stabilization rather than fusion.

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The Effect of Lumbar Lordosis on Screw Loosening in Dynesys Dynamic Stabilization: Four-Year Follow-Up with Computed Tomography

BioMed Research International ◽

10.1155/2015/152435 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 7

Author(s):

Chao-Hung Kuo ◽

Peng-Yuan Chang ◽

Tsung-Hsi Tu ◽

Li-Yu Fay ◽

Hsuan-Kan Chang ◽

...

Keyword(s):

Computed Tomography ◽

Clinical Outcomes ◽

Lumbar Lordosis ◽

Degenerative Spondylolisthesis ◽

Dynamic Stabilization ◽

Leg Pain ◽

Screw Loosening ◽

Disc Disease ◽

Radiographic Outcomes

Introduction. This study aimed to evaluate the effects of Dynesys dynamic stabilization (DDS) on clinical and radiographic outcomes, including spinal pelvic alignment.Method. Consecutive patients who underwent 1- or 2-level DDS for lumbar spondylosis, mild degenerative spondylolisthesis, or degenerative disc disease were included. Clinical outcomes were evaluated by Visual Analogue Scale for back and leg pain, Oswestry Disability Index, and the Japanese Orthopedic Association scores. Radiographic outcomes were assessed by radiographs and computed tomography. Pelvic incidence and lumbar lordosis (LL) were also compared.Results. In 206 patients with an average follow-up of 51.1 ± 20.8 months, there were 87 screws (8.2%) in 42 patients (20.4%) that were loose. All clinical outcomes improved at each time point after operation. Patients with loosened screws were 45 years older. Furthermore, there was a higher risk of screw loosening in DDS involving S1, and these patients were more likely to have loosened screws if the LL failed to increase after the operation.Conclusions. The DDS screw loosening rate was overall 8.2% per screw and 20.4% per patient at more than 4 years of follow-up. Older patients, S1 involvement, and those patients who failed to gain LL postoperatively were at higher risk of screw loosening.

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Peculiarities of Treatment of Patients with Complicated Compression Fractures of Thoracic and Lumbar Spine Vertebral Bodies on the Background of Osteoporosis

N.N. Priorov Journal of Traumatology and Orthopedics ◽

10.17816/vto200916234-39 ◽

2009 ◽

Vol 16 (2) ◽

pp. 34-39

Author(s):

S T Vetrile ◽

Aleksandr Alekseevich Kuleshov ◽

L Yu Darchiya ◽

S T Vetrile ◽

A A Kuleshov ◽

...

Keyword(s):

Lumbar Spine ◽

Term Treatment ◽

Mineral Density ◽

Compression Fractures ◽

Long Term Treatment ◽

Thoracic And Lumbar Spine ◽

Vertebral Bodies ◽

Adequate Decompression

Experience in surgical treatment of 11 patients (1998-2008) with complicated compression fractures of the thoracic and lumbar spine vertebral bodies on the background of osteoporosis has been presented. Mean age of patients was 58 years (from 37 to 74 years). The treatment consisted of the adequate decompression of spinal canal followed by correction and multilevel fixation of the spine with CDI system. Decision on the fixation extent was made with regard for the degree of bone mineral density and vertebral body injury. Follow up period made up 1-10 years. Long term treatment results were assessed clinically and roentgenologically. Correction of kyphosis was noted in all cases. In the late period slight loss of the achieved correction (within 12°) was observed but the patients did not complained of spinal pains. In patients operated on in early terms (up to 2 months) after neurologic complications development the more rapid regress of neurologic symptoms was noted. It was shown that differentiated approach to the choice of surgical technique enabled to achieve favorable results.

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Revision by S2-alar-iliac instrumentation reduces caudal screw loosening while improving sacroiliac joint pain—a group comparison study

Neurosurgical Review ◽

10.1007/s10143-020-01377-1 ◽

2020 ◽

Author(s):

Sandro M. Krieg ◽

Nico Sollmann ◽

Sebastian Ille ◽

Lucia Albers ◽

Bernhard Meyer

Keyword(s):

Sacroiliac Joint ◽

Comparison Study ◽

Screw Loosening ◽

Mineral Density ◽

Biomechanical Force ◽

Iliac Screws ◽

The Mean ◽

Caudal Level ◽

Sacral Bone

Abstract Lumbosacral instrumentation continues to be challenging due to complex biomechanical force distributions and poor sacral bone quality. Various techniques have therefore been established. The aim of this study was to investigate the outcome of patients treated with S2-alar-iliac (S2AI), S2-alar (S2A), and iliac (I) instrumentation as the most caudal level. Sixty patients underwent one of the 3 techniques between January 2012 and June 2017 (S2AI 18 patients, S2A 20 patients, I 22 patients). Mean age was 70.4 ± 8.5 years. Screw loosening (SL) and sacroiliac joint (SIJ) pain were evaluated during the course at 3-month and maximum follow-up (FU). All patients completed 3-month FU, the mean FU period was 2.5 ± 1.5 years (p = 0.38), and a median of 5 segments was operated on (p = 0.26), respectively. Bone mineral density (BMD), derived opportunistically from computed tomography (CT), did not significantly differ between the groups (p = 0.66), but cages were more frequently implanted in patients of the S2A group (p = 0.04). SL of sacral or iliac screws was more common in patients of the S2A and I groups compared with the S2AI group (S2AI 16.7%, S2A 55.0%, I 27.3% of patients; p = 0.03). SIJ pain was more often improved in the S2AI group not only after 3 months but also at maximum FU (S2AI 61.1%, S2A 25.0%, I 22.7% of patients showing improvement; p = 0.02). Even in shorter or mid-length lumbar or thoracolumbar constructs, S2AI might be considered superior to S2A and I instrumentation due to showing lower incidences of caudal SL and SIJ pain.

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Pregnancy- and lactation-associated osteoporosis with vertebral fractures

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh210329038b ◽

2021 ◽

pp. 38-38

Author(s):

Aleksandar Bozovic ◽

Zlatan Elek ◽

Petar Jovanovic ◽

Dejan Tabakovic ◽

Nenad Milosevic ◽

...

Keyword(s):

Vitamin D ◽

Back Pain ◽

Vertebral Fractures ◽

Pathophysiological Mechanism ◽

Mineral Density ◽

Pregnancy And Lactation ◽

Vertebral Bodies ◽

Magnetic Resonance Imaging Mri ◽

The Stability

Introduction. Pregnancy- and lactation- associated osteoporosis (PLO) is a rare disease for which the pathophysiological mechanism is as yet incompletely known. The incidence of PLO is 0.4 in 100,000 women. It is considered that the number of undiagnosed patients is even higher. PLO can lead to multiple fragility compression fractures in the spinal vertebrae. Case outline. We present the case of a 30 years old woman (first-born, breastfeeding child) who comes for examination due to lower back pain that occurs after childbirth without any apparent cause. The patient was found to have low levels of vitamin D and low bone mineral density on osteodensitometry (established osteoporosis). Magnetic resonance imaging (MRI) examination showed vertebral bodies fractures Th11, Th12 and L4. In therapy we used Vitamin D (800 iu/24 h), Alendronate (70 mg once weekly), calcium 1000 mg/24h and Thoracic Lumbar Sacral Orthosis (TLSO) as support to spine. After 12 months of treatment osteodensitometry findings were close to normal, control MRI showed no further collapse of vertebral bodies and clinical examination of spine was orderly. Conclusion. PLO is a rare clinical condition and it must be kept in mind in the differential diagnosis in patients having low back pain during or after pregnancy. Early diagnosis and treatment of PLO and regular follow-up of these cases are particularly important. The stability of the spine in patients with vertebral fractures must be carefully monitored as well as using the TLSO as a support for the spine.

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Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients

Neurosurgical FOCUS ◽

10.3171/2011.7.focus11125 ◽

2011 ◽

Vol 31 (4) ◽

pp. E9 ◽

Cited By ~ 61

Author(s):

Jau-Ching Wu ◽

Wen-Cheng Huang ◽

Hsiao-Wen Tsai ◽

Chin-Chu Ko ◽

Ching-Lan Wu ◽

...

Keyword(s):

Clinical Outcomes ◽

Serum Glucose ◽

Dynamic Stabilization ◽

Diabetic Patients ◽

Screw Loosening ◽

Osseous Integration ◽

Incidence Risk ◽

The Mean ◽

Lumbar Dynamic Stabilization

Object The long-term outcome of lumbar dynamic stabilization is uncertain. This study aimed to investigate the incidence, risk factors, and outcomes associated with screw loosening in a dynamic stabilization system. Methods The authors conducted a retrospective review of medical records, radiological studies, and clinical evaluations obtained in consecutive patients who underwent 1- or 2-level lumbar dynamic stabilization and were followed up for more than 24 months. Loosening of screws was determined on radiography and CT scanning. Radiographic and standardized clinical outcomes, including the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores, were analyzed with a focus on cases in which screw loosening occurred. Results The authors analyzed 658 screws in 126 patients, including 54 women (42.9%) and 72 men (57.1%) (mean age 60.4 ± 11.8 years). During the mean clinical follow-up period of 37.0 ± 7.1 months, 31 screws (4.7%) in 25 patients (19.8%) were shown to have loosened. The mean age of patients with screw loosening was significantly higher than those without loosening (64.8 ± 8.8 vs 59.3 ± 12.2, respectively; p = 0.036). Patients with diabetes mellitus had a significantly higher rate of screw loosening compared with those without diabetes (36.0% vs 15.8%, respectively; p = 0.024). Diabetic patients with well-controlled serum glucose (HbA1c ≤ 8.0%) had a significantly lower chance of screw loosening than those without well-controlled serum glucose (28.6% vs 71.4%, respectively; p = 0.021). Of the 25 patients with screw loosening, 22 cases (88%) were identified within 6.6 months of surgery; 18 patients (72%) had the loosened screws in the inferior portion of the spinal construct, whereas 7 (28%) had screw loosening in the superior portion of the construct. The overall clinical outcomes at 3, 12, and 24 months, measured by VAS for back pain, VAS for leg pain, and ODI scores, were significantly improved after surgery compared with before surgery (all p < 0.05). There were no significant differences between the patients with and without screw loosening at all evaluation time points (all p > 0.05). All 25 patients with screw loosening were asymptomatic, and in 6 (24%) osseous integration was demonstrated on later follow-up. Also, there were 3 broken screws (2.38% in 126 patients or 0.46% in 658 screws). To date, none of these loosened or broken screws have required revision surgery. Conclusions Screw loosening in dynamic stabilization systems is not uncommon (4.7% screws in 19.8% patients). Patients of older age or those with diabetes have higher rates of screw loosening. Screw loosening can be asymptomatic and presents opportunity for osseous integration on later follow-up. Although adverse effects on clinical outcomes are rare, longer-term follow-up is required in cases in which screws become loose.

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Dynamic stabilization for degenerative diseases in the lumbar spine: 2 years results

Orthopedic Reviews ◽

10.4081/or.2018.7534 ◽

2018 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Ahmed Hosny Khalifa ◽

Timo Stübig ◽

Oliver Meier ◽

Christian Walter Müller

Keyword(s):

Lumbar Fusion ◽

Adjacent Segment Degeneration ◽

Dynamic Stabilization ◽

Leg Pain ◽

Adjacent Segment ◽

Degenerative Lumbar Disease ◽

Vas Scores ◽

Posterior Dynamic Stabilization ◽

The Mean

Following lumbar fusion, adjacent segment degeneration has been frequently reported. Dynamic systems are believed to reduce main fusion drawbacks. We conducted a retrospective study on patients with degenerative lumbar disease treated with posterior dynamic stabilization with monoaxial hinged pedicular screws and lumbar decompression. VAS and ODI were used to compare clinical outcomes. As radiological outcomes, LL and SVA were used. 51 patients were included with an average follow-up of 24 months. 13 patients were revised because of postoperative radiculopathy (n=4), subcutaneous hematoma(n=2), L5 screw malposition (n=1) and adjacent segment disease (n=6). The mean ODI score 41 preoperatively compared to 36 postoperatively. The mean VAS scores for back and leg pain were 5.3 and 4.2, respectively compared to 4.5 and 4.0 post-operatively. The mean SVA was 5.3 cm pre-operatively, and 5.7 cm postoperatively. The mean LL was 47.5° preoperatively and 45.5° postoperatively. From our data, whichfail to show significant improvements andreflect a high revision rate, we cannot generally recommend dynamic stabilization as an alternative to fusion. Comparative trials with longer follow-ups are required.

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Posterior lumbar dynamic stabilization instead of arthrodesis for symptomatic adjacent-segment degenerative stenosis: description of a novel technique

Neurosurgical FOCUS ◽

10.3171/2015.10.focus15413 ◽

2016 ◽

Vol 40 (1) ◽

pp. E5 ◽

Cited By ~ 2

Author(s):

Hazem Mashaly ◽

Erin E. Paschel ◽

Nicolas K. Khattar ◽

Ezequiel Goldschmidt ◽

Peter C. Gerszten

Keyword(s):

Lumbar Fusion ◽

Dynamic Stabilization ◽

Neurogenic Claudication ◽

Adjacent Segment ◽

Fusion Surgery ◽

Instrumented Fusion ◽

Novel Technique ◽

The Mean ◽

Lumbar Dynamic Stabilization

OBJECTIVE The development of symptomatic adjacent-segment disease (ASD) is a well-recognized consequence of lumbar fusion surgery. Extension of a fusion to a diseased segment may only lead to subsequent adjacent-segment degeneration. The authors report the use of a novel technique that uses dynamic stabilization instead of arthrodesis for the surgical treatment of symptomatic ASD following a prior lumbar instrumented fusion. METHODS A cohort of 28 consecutive patients was evaluated who developed symptomatic stenosis immediately adjacent to a previous lumbar instrumented fusion. All patients had symptoms of neurogenic claudication refractory to nonsurgical treatment and were surgically treated with decompression and dynamic stabilization instead of extending the fusion construct using a posterior lumbar dynamic stabilization system. Preoperative symptoms, visual analog scale (VAS) pain scores, and perioperative complications were recorded. Clinical outcome was gauged by comparing VAS scores prior to surgery and at the time of last follow-up. RESULTS The mean follow-up duration was 52 months (range 17–94 months). The mean interval from the time of primary fusion surgery to the dynamic stabilization surgery was 40 months (range 10–96 months). The mean patient age was 51 years (range 29–76 years). There were 19 (68%) men and 9 (32%) women. Twenty-three patients (82%) presented with low-back pain at time of surgery, whereas 24 patients (86%) presented with lower-extremity symptoms only. Twenty-four patients (86%) underwent operations that were performed using single-level dynamic stabilization, 3 patients (11%) were treated at 2 levels, and 1 patient underwent 3-level decompression and dynamic stabilization. The most commonly affected and treated level (46%) was L3–4. The mean preoperative VAS pain score was 8, whereas the mean postoperative score was 3. No patient required surgery for symptomatic degeneration rostral to the level of dynamic stabilization during the follow-up period. CONCLUSIONS The use of posterior lumbar dynamic stabilization may offer a valid and safe option for the management of patients who develop ASD rostral to a previously instrumented arthrodesis. The technique may serve as an alternative to multilevel arthrodesis in this patient population. By implanting a dynamic stabilization device instead of an extension of a rigid construct, this might translate into a reduction in the development of yet another level of ASD.

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The Role of Hounsfield Unit in Intraoperative Endplate Violation and Delayed Cage Subsidence with Oblique Lateral Interbody Fusion

Global Spine Journal ◽

10.1177/21925682211052515 ◽

2021 ◽

pp. 219256822110525

Author(s):

Hao Wu ◽

Jason Pui Yin Cheung ◽

Teng Zhang ◽

Zhi Shan ◽

Xuyang Zhang ◽

...

Keyword(s):

Interbody Fusion ◽

Posterior Instrumentation ◽

Case Series ◽

Hounsfield Unit ◽

Mineral Density ◽

Lateral Interbody Fusion ◽

Cage Subsidence ◽

Oblique Lateral Interbody Fusion ◽

Lateral Interbody

Study Design Retrospective clinical case series. Objectives To investigate the risk factors for intraoperative endplate violations and delayed cage subsidence after oblique lateral interbody fusion (OLIF) surgery. Secondly, to examine whether low Hounsfield unit (HU) values at different regions of the endplate are associated with intraoperative endplate violation or delayed cage subsidence. Methods 61 patients (aged 65.1 ± 9.5 years; 107 segments) who underwent OLIF with or without posterior instrumentation from May 2015 to April 2019 were retrospectively studied. Intraoperative endplate violation was measured on sagittal reconstructed computerized tomography (CT) images immediate postoperatively, while delayed cage subsidence was evaluated using lateral radiographs and defined at 1-month follow-up or later. Demographic information and clinical parameters such as age, body mass index, bone mineral density, number of surgical levels, cage dimension, disc height restoration, visual analogue scale (VAS), and HU at different regions of the endplate were obtained. Results Total postoperative cage subsidence was identified in 45 surgical levels (42.0%) in 26 patients (42.6%) up till postoperative 1-year follow-up. Low HU value at the ipsilateral epiphyseal ring was an independent risk factor for intraoperative endplate violation ( P = .008) with a cut-off value of 326.21 HUs. Low HU values at the central endplate had a significant correlation with delayed cage subsidence in stand-alone cases ( P = .013) with a cut-off value of 296.42 HUs. VAS scores were not different at 1 week postoperatively in cases with or without intraoperative endplate violation (3.12 ± .73 vs 2.89 ± .72, P = .166) and showed no difference at 1 year with or without delayed cage subsidence (1.95 ± .60 vs 2.26 ± .85, P = .173). Conclusions Intraoperative endplate violation and delayed cage subsidence are not uncommon with OLIF surgery. HUs of the endplate are good predictors for intraoperative endplate violation and cage subsidence since they can represent the regional bone quality of the endplate in contact with the implant. VAS improvements were not affected by intraoperative endplate violation or delayed cage subsidence at 1-year follow-up. Level of Evidence Level III.

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